Streaks of fire lit the sky as ejecta continued to fall to the Earth.
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Ejecta is material forced or thrown out from an eruption or some sort of impact.
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Every streaking flare of ejecta in the sky just drove home how helpless we were.
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Vectors illustrating the observed proper motions of 792 features in the ejecta of Eta Carinae.
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Some of the ejecta escaped Earth's gravitational pull and went into irregular orbits around the sun.
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But the Cow had very little ejecta mass, which allowed us to view the central engine's radiation directly.
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Where the new ejecta meets the older debris, it piles up into a shock, inside which magnetic fields soar.
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Ejecta The process of cratering is likely to throw up a huge amount of rocks and debris into the air.
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Astronauts Alan Shepard and Edgar Mitchell collected samples from the ejecta of the crater and brought them back to Earth.
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In the beginning we built a studio in Pat's apartment and I was there every day working on that first Ejecta record.
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Tiny course correction ejecta refined the descent vector, steering it at Tierra del Fuego, which was still thirty minutes from greeting the dawn.
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Some ejecta from volcanoes even fall back on the surfaces of other moons like Europa, a prime candidate in the search for life.
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Nicolle Zellner, professor at Albion College in Michigan, told Gizmodo that she was excited for samples that didn't contain ejecta from the Imbrium event.
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Fra Mauro is composed of ejecta from a celestial collision between an asteroid and the Moon, which excavated the biggest lunar impact basin, Mare Imbrium.
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However, both ejecta and cratering are considered to be low risk because humans would have already been killed by the other effects of an asteroid impact.
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The devastation caused by the impact included massive tsunami-like surges and "ejecta" -- torrents of rocks, like fine sand and small glass beads -- the report said.
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That streak of light had been a chunk of ejecta slamming into the nose of the plane, and it had taken part of my propeller with it.
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However, he added that if the ejecta came from a different, or perhaps much smaller, impact at a different time and place, or the ejecta did come from Chicxulub but stayed in the water system for a long time afterward, "then it is possible that the fish etc died for some other reason -- something less spectacular and more local -- and had little to do with the Chicxulub impact."
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Within days, he said, supernova ejecta traveling at the incredible velocity of 10,000 kilometers per second engulf the regions surrounding exploding stars, destroying evidence of the initial collapse.
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For sorting through the ejecta from the collisions gives physicists fleeting glimpses of the fundamental building blocks of the universe and the forces that bind or repel them.
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By modeling the evolution of ejecta fragments from the collision, researchers of a 2015 study on lunar formation estimated the moon formed around 4.47 billion years ago. 8.
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Given its large size and hints of ancient ejecta, Ismenia Patera is clearly the result of some spectacularly catastrophic event, but scientists aren't exactly sure what that blast might have been.
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So much ejecta would have darkened skies worldwide, causing scientists to speculate that it might have plunged the Earth into a volcanic winter whose chill could be felt far from Indonesia.
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The sandstone outcrop contained fractured quartz grains, which the geologists think were proximal ejecta from the meteorite — the term for material that gets pushed out from an impact site into nearby rocks.
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Nobody brought a thermometer, either, but ejecta of that sort can easily start its skyward journey at about 1,800 degrees Fahrenheit, which would have burned a pretty good hole through my shirt — and right down to bone.
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When a volcano erupts, it might take out some neighboring towns and mess with air traffic, but a supervolcano—a volcano that ejects material (ejecta) on the order of quadrillions of kilograms—can be expected to spread pyroclastic flows for hundreds of miles and dump ash even further out than that.
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In their storied careers, Farmer and/or Ward have been harrassed by authorities in Argentina; nearly abducted by FARC gunmen outside Kali, Colombia; and robbed in Kenya, where Farmer, in search of a new ejecta field, was captured, hooded, and later told by his driver that his Swahili-speaking robbers were deliberating whether they should kill him.
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Ejecta blankets settle asymmetrically around their craters, but fast-moving ejecta that escapes from the asteroid is permanently lost.
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Ejecta blanket is a common feature to seen on the martian impact craters specifically around fresh impact crater. One-third of the martian impact craters with ≥ 5 km diameter have discernible impact ejecta around. Layered ejecta blanket are plentiful on the surface of Mars as around 90% of ejecta are characterized as layered materials. Though impact cratering and resulted ejecta blanket are ubiquitous features in the solid bodies of the solar system, the Earth rarely preserve the signature of impact ejecta blanket due to erosion.
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Over 90% of the debris falls within approximately 5 radii of the center of the crater. Ejecta which falls within that area is considered proximal ejecta. Beyond 5 radii, the discontinuous debris is considered distal ejecta.
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Ejecta mobility of layered ejecta craters on Mars: Assessing the influence of snow and ice deposits. Icarus: 233, 131–146.
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The martian ejecta blankets are categorized broadly into three groups based on the observed morphology identified by spacecraft data: a. Layer ejecta pattern: the ejecta blanket seems have formed by fluidization process and composed of single or multiple partial or complete layers of sheet of materials surrounding the crater. Sometime eolian modification are also common. b. Radial ejecta blanket: the ejecta materials are emplaced by the secondary materials ejected along a balletic trajectory.
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There are also areas in the lowlands that are outside any of the impact basins, these areas must be overlain by multiple ejecta blankets and should stand at elevations similar to the original planetary surface. That clearly is not the case either. One approach explaining the absence of ejecta blankets infers that no ejecta was ever present. Absence of ejecta could be caused by a large impactor scattering the ejecta into outer space.
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Single-layer ejecta craters only penetrate into the icy upper layer, as shown on the left. Multiple-layer ejecta craters go all the way through the icy layer and somewhat into the lower, ice-free layer (right). Another type of rampart crater is called a double-layered ejecta (DLE) crater. It displays two lobes of ejecta.
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Copernicus (upper center, yellow), ejecta blanketed the surrounding area. Blue denotes the outline of the ejecta deposit; secondary craters and crater chains are orange.
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In contrast, the ejecta blankets and proximal ejecta deposits of Moon and Mercury (or on airless bodies) are attributed to ballistic sedimentation. Lunar fresh impact craters preserve continuous ejecta blanket that are characterized by blocky and high albedo materials. Similar to the fresh lunar craters, the Mercurian impact craters also form continuous ejecta deposits of blocky and high albedo materials. Radial structure of ejecta deposits are seen around the lunar impact crater and generally thins out as increase distance form the center of the crater.
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The unusual rectilinear map pattern of the ejecta suggests: (1) control of the ejecta pattern by prebasin structures, (2) preferential burial along structural trends of an originally symmetrical ejecta blanket by the intercrater plains material, or (3) formation of Tolstoj by an oblique impact from the northwest that produced an ejecta blanket with bilateral symmetry and little or no deposition uprange. Analysis of stereo- photography of Tolstoj ejecta northeast of the crater suggests that this deposit has been upwarped to a higher elevation relative to the surrounding plains.
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Immediately after an impact event, the falling debris forms an ejecta blanket surrounding the crater. An ejecta blanket is deposited in the interior regions of the crater rim to the final crater rim and beyond the crater rim. Approximately half the volume of ejecta falls within 1 crater radius of the rim, or 2 radii from the center of the crater. The ejecta blanket becomes thinner with distance and increasingly discontinuous.
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Yuty and its ejecta. This is classified as a multiple-layer ejecta crater. Rampart craters are a specific type of impact crater which are accompanied by distinctive fluidized ejecta features found mainly on Mars. There is one example known on Earth, the Nördlinger Ries impact structure in Germany.
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The earliest known eruption occurred about 1.5 million years ago. Although it is difficult to estimate ejecta volume due to erosion and more recent activity covering this eruptions ejecta, an estimate of ejecta volume has been produced by the discoverers, i.e. ~ 825 cubic km. After this eruption, an uplifted block formed.
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Radial lineations with a slight swirly pattern are best seen on the southwest side of Tolstoj. The unusual rectilinear map pattern of the ejecta suggests: (1) control of the ejecta pattern by prebasin structures, (2) preferential burial along structural trends of an originally symmetrical ejecta blanket by the intercrater plains material, or (3) formation of Tolstoj by an oblique impact from the northwest that produced an ejecta blanket with bilateral symmetry and little or no deposition uprange. Analysis of stereophotography of Tolstoj ejecta northeast of the crater suggests that this deposit has been upwarped to a higher elevation relative to the surrounding plains.
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Studying impact ejecta is an excellent sampling environment for the future in-situ lunar exploration. Ejecta blanket may not always evenly distributed around an impact crater. Based on the structure, ejecta blanket are described as rampart, lobate, butterfly, splosh, sinuous, etc. Many factors determine the extent of ejecta blanket that ranging from size and mass of impactor (meteorite, asteroid, or comet), surface temperature, gravity and atmospheric pressure of target body, the physical characteristics of target rock.
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Related to these are (MLE) craters that have more than 2 or more layers of ejecta. They are larger than single layered ejecta craters, having an average diameter of 22 km. Their ejecta are about 2.2 radii from the crater rim. They are more concentrated near the equator (mostly between 40 degrees from the equator).
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Ejecta blankets are found on the terrestrial planets (e.g., Earth, Mars, and Mercury) and satellites (e.g., Moon). Many of the ejecta blankets of Mars are characterized by fluidized flowing across the surface.
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The Caloris Basin is especially significant from a stratigraphic standpoint. Like the Imbrium and Orientale Basins on the Moon, it is surrounded by an extensive and well-preserved ejecta blanket. As on the Moon, where ejecta from the better preserved basins was used to construct a stratigraphy, the ejecta from the Caloris Basin also can be used as a marker horizon. This ejecta is recognizable to a distance of about one basin diameter in the Tolstoj quadrangle and the adjacent Shakespeare quadrangle to the north.
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Schaber G.G. et al. (1977) PEPI 15, 189. It has a well-preserved ejecta blanket extending outward as much as from its rim. The basin interior is flooded with plains that clearly postdate the ejecta deposits.
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Aurelia is a crater on Venus. It has a large dark surface up range from the crater; lobate flows emanating from crater ejecta, and very radar-bright ejecta and floor. The crater takes its name from Aurelia.
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Presence of boulder materials are also seen in the lunar ejecta deposits. However, the diameter of boulder found in ejecta deposits are directly correlated with the size of impact crater diameter. The low gravity and lack of atmosphere (air less bodies) favors the formation of the impact cratering and associated ejecta black on the surface of moon and Mercury. Although a thick atmosphere and relatively higher gravity of Venus reduce the likelihood impact cratering, the higher surface temperature augments the efficiency of the impact melting and associated ejecta deposits.
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As on the Moon, where ejecta from the better preserved basins was used to construct a stratigraphy, the ejecta from the Caloris Basin also can be used as a marker horizon. This ejecta is recognizable to a distance of about one basin diameter in the Tolstoj quadrangle and the adjacent Shakespeare quadrangle to the north. Undoubtedly, the ejecta also influences a large part of the terrain to the west that was recently photographed by MESSENGER. A stratigraphic and structural comparison between the Orientale and Caloris Basins has been made by McCauley.
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Young Ejecta (formerly known as simply Ejecta) is an American synthpop duo, consisting of Neon Indian's Leanne Macomber and producer Joel Ford of Ford & Lopatin. The band name was changed to Young Ejecta in 2014 due to the group getting a copyright notice from the closely named DJ Ejeca. Macomber appears nude on all official album covers and promotional material, and in most of their music videos.
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Some of this ejecta may have been deposited within the interior of Hohmann.
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The surviving rim and the remaining interior floor are relatively indistinct, possibly due to deposits of ejecta from the Mare Orientale impact basin to the northeast. Radial streaks of ejecta and secondary craters cover the terrain that surrounds Stetson and Blackett.
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The calculation of depth of secondary crater can be formulated based on the target body's density. Studies of the Nördlinger Ries in Germany and of ejecta blocks circling lunar and martian crater rims suggest that ejecta fragments having a similar density would likely express the same depth of penetration, as opposed to ejecta of differing densities creating impacts of varying depths, such as primary impactors, i.e. comets and asteroids.
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These may be ejecta from it. The canyons have been collectively named Samhain Catena.
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This rough debris blanket of ejecta is referred to as the "Fra Mauro Formation".
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Based on images from the Viking program in the 1970s, it is generally accepted that rampart craters are evidence of ice or liquid water beneath the surface of Mars. The impact melts or boils the water in the subsurface producing a distinctive pattern of material surrounding the crater. Ryan Schwegman described double layered ejecta (DLE) craters as showing two distinct layers of ejecta that appear to have been put in place as a mobile, ground-hugging flow. His measurements suggest that ejecta mobility (the distance ejecta travels from the crater rim) typically goes up with increasing latitude and may reflect ice concentration.
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Barlow, N., J. Boyce, C. Cornwalc. Martian Low-Aspect-Ratio Layered Ejecta (LARLE) craters: Distribution, characteristics, and relationship to pedestal craters. Icarus:239, 186-200. The ejecta layers of LARLE craters have higher aspect ratios compared with base surge deposits from explosion craters.
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Achelous is a relatively fresh crater on Ganymede adjacent to the similarly sized Gula. It has an outer lobate ejecta deposit extending about a crater radius from the rim. A characteristic feature of both craters, almost identical in size, is the "pedestal" - an outward-facing, relatively gently sloped scarp that terminates the continuous ejecta blanket. Similar features may be seen in ejecta blankets of Martian craters, suggesting impacts into a volatile (ice)-rich target material.
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That is the higher the latitude, the greater the ice content. The lobateness (curved shape of the perimeter of ejecta) usually goes down with increasing latitude. Furthermore, DLEs on sedimentary ground seem to display higher ejecta mobility than those on volcanic surfaces.Schwegman, R. 2015.
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In November 2013, Ejecta released their debut album, Dominae. In 2015 issued their mini-album and second studio LP The Planet. The album received an indifferent review from PopMatters"Young Ejecta The Planet". PopMatters, Colin Fitzgerald, 2 February 2015 and a fairly positive one from Paste magazine.
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Beethoven has only one, subdued massif-like rim in diameter, but displays an impressive, well lineated ejecta blanket that extends as far as . As at Tolstoj, Beethoven ejecta is asymmetric. The Caloris basin is defined by a ring of mountains in diameter.McCauley J.F. (1977) PEPI 15, 220.
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This alder ejecta area is on spectrographic evidence instead principally anorthosite rock, typical of the lunar highlands.
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The impact nature is documented by abundant polymictic and monomictic breccias, breccia dikes, extensive megabreccias and impact ejecta, dislocated megablocks, geophysical anomalies and shock metamorphism. Shock effects like melt glass, diaplectic glass, planar deformation features (PDFs) are found in breccias and breccia dikes, and PDFs are abundant also in quartzite clasts contributing to the ejecta (Pelarda Formation).Ernstson K. and Claudin F. (1990) Pelarda Formation (Eastern Iberian Chains, NE Spain): Ejecta of the Azuara impact structure. N. Jb. Geol. Paläont. Mh.:581-599.
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However, ejecta appear to be almost absent on the west side of the basin. The reason for this asymmetry is unclear; possibly Beethoven is the result of an oblique impact that produced an asymmetric ejecta distribution (Gault and Wedekind, 1978), or possibly basin radial texture in the western rim area has been obliterated by ejecta from Valmiki. The other basins in the quadrangle are Michelangelo, Valmiki, and Bach. All contain two rings and appear to be transitional between large craters and multiring basins.
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The same forces that cause the ejecta of a firearm (the projectile(s), propellant gas, wad, sabot, etc.) to move down the barrel also cause all or a portion of the firearm to move in the opposite direction. The result is required by the conservation of momentum such that the ejecta momentum and recoiling momentum are equal. These momenta are calculated by: : Ejecta mass × ejecta velocity = recoiling mass × recoil velocity In non-recoil-operated firearms, it is generally the entire firearm that recoils. However, in recoil-operated firearms, only a portion of the firearm recoils while inertia holds another portion motionless relative to a mass such as the ground, a ship's gun mount, or a human holding the firearm.
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A widespread layer of ejecta, believed to be from the Acraman crater, is found within Ediacaran rocks of the Flinders Ranges at least east of the crater, and in drill holes from the Officer Basin to the north. At the time these areas were shallow sea, and the ejecta settled into mud on the sea floor. The ejecta, containing shocked minerals and small shatter cones, is composed of rock similar in age and composition to that at the crater, and is associated with an iridium anomaly suggesting contamination with extraterrestrial material. An evolutionary radiation within marine microorganisms (acritarchs) occurs just above the level as the ejecta layer, and some authors believe there may be a connection.
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These narrow lines indicate the presence of a dense circumstellar medium (CSM) in the vicinity of the supernova. The high luminosity of SN1998S is due to the interaction of fast material (ejecta) with previously-expelled slowly- expanding material (CSM), which can more effectively convert kinetic energy of ejecta into radiation energy.
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Magnetic clouds represent about one third of ejecta observed by satellites at Earth. Other types of ejecta are multiple- magnetic cloud events (a single structure with multiple subclouds distinguishable)Wang, Y. M., et al., Multiple magnetic clouds in interplanetary space, Solar Physics, 211, 333-344, 2002.Wang, Y. M., et al.
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Published by The Defense Mapping Agency, November 1974. Available from Lunar and Planetary Institute. with a bright system of rays of ejecta. The astronauts observed that the ejecta of South Ray was very bouldery, and reported that it would have been difficult or impossible to drive there on their rover.
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In 1991, NASA and The Planetary Society Pasadena sponsored an expedition led by Ocampo and Pope. During this expedition, Ocampo and her colleges discovered two new sites containing two layers consisting of particles that had been ejected upon impact of the asteroid and then flowed away, generating ejecta lobes. The ejecta lobes at Chicxulub are key to understanding Mars better, since most of that planet is covered by ejecta. Ocampo was awarded her master thesis on the Chicxulub impact crater at California State University.
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A blanket of ejecta is formed during the formation of meteor impact cratering and is composed usually of the materials of that are ejected from the cratering process. Ejecta materials are deposited on the preexisting layer of target materials and therefore it form an inverted stratigraphy than the underlying bedrock. In some cases, the excavated fragment of ejects materials can form secondary craters. The materials of ejecta blanket come from rock fragments of crater excavation, materials due to impact melting, and outside the crater.
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Its appearance changes over time through a process called space weathering. Because of this process, older regolith appears more red in color compared to freshly exposed material. 216x216px About 20 large (40–150 m across) ejecta blocks have been identified, embedded in Ida's regolith. Ejecta blocks constitute the largest pieces of the regolith.
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This radial patterns are also found around the lunar and Mercurian craters. c. Combination of layered and radial ejecta pattern.
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The crater features have a softened appearance, possibly due to overlying ejecta from the much larger Schwarzschild and Compton impacts.
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Ejecta blankets have a diverse morphology. Variations in ejecta blanket indicates different geological characteristics involved with the impact cratering process such as nature of target materials and kinetic energy involved with the impact process. These information also give an idea about the planetary environment e.g., gravity and atmospheric effects associated with the impact cratering.
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A thick lateral layer between the metasedimentary Gunflint Iron Formation and overlying Rove Formation, and between the Biwabik Iron Formation and overlying Virginia Formation has evidence that the layer contains hypervelocity impact ejecta. Radiometric dating reveals that this layer was deposited between 1,878 and 1,836 million years ago. The Sudbury Impact event - which occurred to the east 1,850 ± 1 million years ago - is the likely ejecta source, making these the oldest ejecta linked to a specific impact. Additional evidence indicates a diameter meteorite collided with earth in the current-day vicinity of Sudbury, Ontario, Canada.
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The impact ejecta from Lofn partially buried nearby Adlinda multi-ring structure, which is situated at the distance of about 500 km to the north-west from it. To the south-east from Lofn there is another multi-ring structure--Heimdall, which geology, however, is poorly known due to the lack of images with the sufficient spatial resolution. The ejecta from Lofn partially covers the eastern part of it. The central zone of Lofn, its rim and the ring of bright ejecta are water rich as was determined by the infrared spectroscopic observations by Galileo.
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The crater lacks bright ejecta deposits and was imaged for the first time by the Voyager 2 spacecraft in January 1986.
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MORPHOLOGY AND MORPHOMETRY OF DOUBLE LAYERED EJECTA CRATERS ON MARS. The School of Graduate and Postdoctoral Studies The University of Western Ontario London, Ontario, Canada. A detailed discussion of various kinds of Martian craters, including double-layer ejecta craters (rampart craters) can be found in a 2014 paper by David Weiss and James Head.Weiss, D., J. Head. 2014.
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There, Apollo 14 had the objective of sampling ejecta from the Imbrium impact to gain insight into the Moon's geologic history. Mission planners chose a landing site near the relatively freshly formed Cone crater, as this crater served as a 'natural drill hole' to allow the astronauts to obtain Imbrium ejecta, a primary objective of the mission.
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Mechanical properties of a target's regolith (existing loose rocks) will influence the angle and velocity of ejecta from primary impacts. Research using simulations has been conducted that suggest that a target body's regolith decreases the velocity of ejecta. Secondary crater sizes and morphology also are affected by the distribution of rock sizes in the regolith of the target body.
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There are a number of different types of craters that have been observed and studied on Mars. Many of the them are shaped by the effects of impacts into ice-rich ground.Weiss, D., J. Head. 2014. Ejecta mobility of layered ejecta craters on Mars: Assessing the influence of snow and ice deposits. Icarus: 233, 131-146.
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Most likely this is ejecta deposited during Tsiolkovskiy's formation. It is named after cosmonaut Viktor Patsayev who died in Soyuz 11 mission.
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Dating of ice cores and Australasian tektites has shown long time span differences between the proposed impact times and the impact ejecta products.
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At the base of the Rove Formation, between the Rove and the underlying Gunflint Iron Formation, there is a lateral layer of shocked quartz and feldspar grains found within accretionary lapilli, accreted grain clusters and spherule masses. These pieces of debris indicate that the layer contains hypervelocity impact ejecta. Zircon geochronologic data shows that this layer formed 1878 to 1836 million years ago; the Sudbury Impact event occurred . Because of the closeness in dating and the nearness of the crater, the Sudbury Impact event is the likely source for the ejecta; these are the oldest ejecta linked to a specific event on Earth.
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Riccioli is older than the Orientale basin to the southwest because the ejecta from the impact that created the Orientale basin overlies the crater. This debris lies in ridges that regionally trend northeast-southwest, but trend in a direction parallel to Riccioli's northeast wall in that part of the crater. A system of rilles named the Rimae Riccioli lies across the interior, and crosscut the ejecta ridges. In the northern half of the interior, the dark covering of lava that resurfaced the floor is visible, and apparently covers some of the ejecta ridges and floods some of the rilles.
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Although rectilinear mountain massifs and the radially lineated facies of basin ejecta of the Caloris Group surround the Caloris Basin, similar units cannot be unambiguously recognized around the Goethe Basin (FDS 164). However, hilly and hummocky remnants resembling basin deposits and ejecta protrude above the gently sloping basin wall. They extend southwest and north of the basin beyond a much subdued, low, barely perceptible rim crest for a distance of one-half to one-third of the basin radius. Goethe is older than the smooth plains material by which its wall, rim crest, and most of its ejecta were partly buried.
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A rampart crater displays an ejecta with a low ridge along its edge. Usually, rampart craters show a lobate outer margin, as if material moved along the surface, rather than flying up and down in a ballistic trajectory. The flows sometimes are diverted around small obstacles, instead of falling on them. The ejecta look as if they move as a mudflow.
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Impact craters generally have a rim with ejecta around them, in contrast volcanic craters usually do not have a rim or ejecta deposits. As craters get larger (greater than 10 km in diameter) they usually have a central peak. The peak is caused by a rebound of the crater floor following the impact. Its rim has probably been eroded away.
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This simple approach to recoil is incomplete since the properties of the bullet alone do not determine the felt recoil, but also the rocket-like blast of propellant gases coming out of the barrel after the bullet leaves the muzzle. A more accurate view on recoil is that it is proportional to the mass of all ejecta × velocity of ejecta.
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The result is that both the crater and its ejecta blanket stand above the surroundings. Pedestal craters were first observed during the Mariner missions.
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On September 12, 2014, Ejecta performed "Afraid of the Dark" at the fourth annual Gorilla vs. Bear festival at the Granada Theater in Dallas, Texas.
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Falling debris litters the ground and drive animals from the valley. Several Triceratops and Ankylosaurus are engulfed by a 300° ejecta cloud and burnt to death. Fifteen minutes after impact, the ejecta cloud has spread to the Pacific Northwest and threatens to in-circulate the entire planet in ash. A pair of Quetzalcoatlus tries to fly away, but pieces of flaming debris shower the valley.
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It was formed during the Copernican period of the moon extending from 1.1 billion years ago to the present. Its young age is indicated by the bright rays of ejecta surrounding the crater, its sharp features, and the relative lack of later impacts in its interior.Li et al., Geological Mapping of Lunar Crater Lalande: Topographic Configuration, Morphology and Cratering Process The rays of ejecta from Lalande overlay the ejecta rays from Copernicus Crater, meaning it is younger than Copernicus, and thus no more than 800 million years old.Apollo 14 Preliminary Science Report In 2002, a meteorite was discovered in the Oman desert by Edwin Gnos of the University of Berne.
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Linus may have formed out of impact ejecta from a collision with Kalliope, or a fragment captured after disruption of a parent asteroid (a proto-Kalliope).
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The eruption initially produced a caldera deep. However, much of the ejecta went straight up, fell down, and filled the initial caldera about two-thirds full.
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Nergal crater is a crater on Jupiter's moon Ganymede. It has a distinctive ejecta blanket surrounding it that's darker nearer the craters and brighter further away. The inner region of the ejecta is characterized by a lobate appearance indicative of the flow of a liquid (or slushy) substance over the surface. The flow was probably icy surface material melted by the energy released during the impact that formed the crater.
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Fresh impact crater on Mars showing a prominent ray system of ejecta. This diameter crater formed between July 2010 and May 2012 (19 November 2013; ).Spectacular new Martian impact crater spotted from orbit, Ars Technica, Feb 6 2014. A ray system comprises radial streaks of fine ejecta thrown out during the formation of an impact crater, looking somewhat like many thin spokes coming from the hub of a wheel.
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61, pp.187–190. 1937 It was the second impact crater to be described in Australia, after Henbury.Haines P.W. (2005). Impact cratering and distal ejecta: the Australian record.
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The energetic neutrons and soft X-rays released by the detonation, which do not appreciably penetrate matter, are converted into thermal heat upon encountering the object's surface matter, ablatively vaporizing all line of sight exposed surface areas of the object to a shallow depth, turning the surface material it heats up into ejecta, and, analogous to the ejecta from a chemical rocket engine exhaust, changing the velocity, or "nudging", the object off course by the reaction, following Newton's third law, with ejecta going one way and the object being propelled in the other. Depending on the energy of the explosive device, the resulting rocket exhaust effect, created by the high velocity of the asteroid's vaporized mass ejecta, coupled with the object's small reduction in mass, would produce enough of a change in the object's orbit to make it miss the Earth. A Hypervelocity Asteroid Mitigation Mission for Emergency Response (HAMMER) has been proposed.
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Superposition relations among craters and basins, and their ejecta, provide the best means of establishing the relative time-stratigraphic order of crater and basin materials. Relative to the Moon, stratigraphic relations among mercurian craters are more clearly discerned because Mercury has a lower density of large craters, and its enhanced gravitational acceleration has restricted the distribution of ejecta. These attributes of the mercurian crater population allow stratigraphic sequences to be constructed over large regions. The degree of crater degradation is determined by qualitative assessment of their landforms such as rim crests, interior wall terraces and slumps, central peaks, continuous ejecta deposits, and secondary crater fields (see Malin and Dzurisin, 1977; McCauley and others, 1981).
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It has been inferred that the original meteorite was in the size range of , probably closer to the latter, now dispersed as fragments within the crater breccia and ejecta.
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Steinheim crater which shows more than one layer of ejecta. These are called double- layered ejecta craters. Evidence leads researchers to believe that they result from an impact that goes through an icy layer and into a rocky layer. There may be more of them closer to the equator because the icy layer is not as thick there; hence more impacts will penetrate all the way through the icy layer and into the rocky layer.
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The Ries impact crater was a rampart crater, thus far a unique finding on Earth. Rampart craters are almost exclusively found on Mars. Rampart craters exhibit a fluidized ejecta flow after impact of the meteorite, most simply compared to a bullet fired into mud, with the ejecta resembling a mudflow. Another impact crater, the much smaller (3.8-km-diameter) Steinheim crater,Johannes Baier & Armin Scherzinger: Der neue Geologische Lehrpfad im Steinheimer Impakt-Krater.
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It is the thickest on the south-east side of Lofn, where it is found at the distance up to 300 km from the center of the crater. The outermost ring of ejecta is made predominantly of dark material. It is especially prominent on the north-west side of Lofn. The patches of ejecta associated with the crater can be found as far as 490 km from its center in the cratered plains.
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The multiple impact hypothesis is supported by correlation of segments of the dichotomy with the rims of several large impact basins. But there are large parts of the Borealis Basin outside the rims of those impact basins. If the Martian lowlands were formed by the multiple basins then their inner ejecta and rims should stand above upland elevations. The rims and ejecta blankets of the lowland impact craters are still much below the upland areas.
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There is a long, narrow valley leading directly away from Schrödinger to the northwest, designated Vallis Schrödinger. This formation begins some distance from the outer rim of the crater, at the edge of the ejecta that surrounds the perimeter. It extends to the rim of the crater Moulton. Another similar valley designated Vallis Planck radiates to the north, beginning near the crater Grotrian at the periphery of the Schrödinger ejecta, and extending past Fechner.
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Surrounding Jenner is a rampart of ejecta that extends for over a half crater diameter in some directions. Mare Australe, with the circular basalt-flooded Jenner prominent in the middle.
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To the east of Nervo are linear ridges trending radially from the Caloris basin, believed to be ejecta from the Caloris impact event, similar to Imbrium sculpture on the Moon.
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Origin of the outer layer of martian low-aspect ratio layered ejecta craters. Icarus:245, 263-272. LARLE craters may be useful as a marker of ice under the surface.
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Possible ash fallout from Eyjafjallajökull on a car, Manchester, England, 21 April 2010 At the mouth of the crater, the gases, ejecta, and volcanic plume have created a rare weather phenomenon known as volcanic lightning (or a "dirty thunderstorm"). When rocks and other ejecta collide with one another, they create static electricity. This, with the abundant water-ice at the summit, aids in making lightning. High-fluoride Hekla eruptions pose a threat to foraging livestock, especially sheep.
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The Exobiology Program of NASA's Office of Space Science and The Planetary Society of Pasadena sponsored an expedition to the second ejecta site in Belize. Ocampo led expeditions there in January 1995, 1996, and 1998. Small particles resembling green glass, and later identified as tektites, were found at the site. These particles, formed from exposure to high temperatures like the ones generated during the impact, linked this site to other ejecta sites in the Caribbean and Mexico.
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Remnant ejecta blankets around parts of the Beethoven are subdued in appearance and their margins poorly defined in places. The crater wall (rim) of Beethoven is buried by its ejecta blanket and by plains materials and is barely visible. The floor of the basin is covered with intermediate smooth plains material, which has the same reflectance as the exterior intermediate terrain. However, there are no wrinkle ridges or graben inside the basin like those in Caloris.
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Some of the smaller craters are secondary craters formed from larger chunks of ejecta from Tycho. It is one of the Moon's brightest craters, with a diameter of and a depth of .
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NASA expects the impact velocity will be over 9,000 km/h (5,600 mph). The ejecta plume will be in the order of 350 tons (317 metric tons) and rise from the surface.
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Australian Journal of Earth Sciences, Volume 52, pp. 481–507. Abstract Henbury was the earliest documented example of impact cratering in Australia. Haines P.W. (2005). Impact cratering and distal ejecta: the Australian record.
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The GRIS detection of a broadened and redshift 847 keV line was some of the first strong evidence for mixing and asymmetries in the ejecta, now recognized as signature characteristics of supernova explosions.
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All supernovae associated with GRBs have shown the high-energy ejecta that characterises them as hypernovae. Unusually bright radio supernovae have been observed as counterparts to hypernovae, and have been termed radio hypernovae.
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Secondary craters are formed around primary craters. When a primary crater forms following a surface impact, the shock waves from the impact will cause the surface area around the impact circle to stress, forming a circular outer ridge around the impact circle. Ejecta from this initial impact is thrust upward out of the impact circle at an angle toward the surrounding area of the impact ridge. This ejecta blanket, or broad area of impacts from the ejected material, surrounds the crater.
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In northeastern Minnesota these banded-iron formations lie immediately under the ejecta layer. Minnesota's Iron Range is composed of this layer of banded-iron formation. Most of the impact layer in the Rove area consists of beccia, a mixture of rock fragments which ripped loose from the sea floor during the earthquakes. The tsunamis jumbled the loosened bedrock and ejecta together; over time this layer was buried by younger sediments, cemented together and fused by molten rock to form a solid layer.
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This soft material may be warm ice or even a subsurface ocean. The impact initially caused the formation of a transient crater with the diameter of about 150 km and depth of about 50 km, which then relaxed forming the present crater with the final diameter of about 300 km. The impact probably penetrated through the dark water poor ejecta of Adlinda and Heimdell, then entered a water ice rich layer beneath it. This explains the distribution of the Lofn's ejecta.
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The ejecta from the volcano devastated the towns around the lake covering them with layers of deposits. The townspeople of Taal, together with their parish priest, fled from their capital and sought refuge at the Church of Our Lady of Caysasay. Layers of ejecta and deposits blocked the entrance of Pansipit River, which eventually raised the water of the lake, permanently flooding parts of Tanauan, Lipa, Sala, Bauan and Taal. All five towns relocated to higher ground, away from the volcano and lake.
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Boltysh crater is located in central Ukraine, in the basin of the Tiasmyn River, a tributary of the Dnieper River. It is in diameter, and is surrounded by an ejecta blanket of breccia preserved over an area of . It is estimated that immediately after the impact, ejecta covered an area of to a depth of or greater, and was some deep at the crater rim. The crater contains a central uplift about in diameter, rising about above the base level of the crater.
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The estimated age of this copernican crater is only a few tens of millions of years. It was earlier believed to have a bowl shape, but data "Linne: Simple Lunar Mare crater geometry from LRO observations", 42nd Lunar and Planetary Science Conference (2011) from the LRO showed that it has a shape of a flattened, inverted cone. The crater is surrounded by a blanket of ejecta formed during the original impact. This ejecta has a relatively high albedo, making the feature appear bright.
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Rock units associated with the Caloris Basin are particularly important for the stratigraphy of Mercury. It has been demonstrated that the history of the Moon was punctuated by a series of major impacts that have emplaced ejecta over widespread areas; the rock units associated with these impact basins were used to divide the lunar stratigraphic column into a series of well-defined time units (Shoemaker and Hackman, 1962; McCauley, 1967; Wilhelms, 1972). These relations are particularly clear for the Imbrium Basin (Wilhelms and McCauley, 1971) and Orientale Basin (Scott and others, 1977). Recognizable ejecta units extend outward from the Caloris Basin as far as one basin diameter; these units can be used to divide the mercurian stratigraphic column in much the same way as basin ejecta were used on the Moon.
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The southwest part of the floor is more irregular than the remainder of the interior, and may have been overlain by ejecta from D'Alembert or elsewhere. The northeastern floor is relatively level and featureless.
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Helicon (left) and Le Verrier (right). While Helicon's ejecta is buried by the mare lava, Le Verrier's is not. (The mountain on the horizon at left is Promontorium Laplace. Image taken by Apollo 15).
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These flow-like features may have formed by fine-grained ejecta transported by a hot, turbulent flow created by the arrival of the impacting object. Alternatively, they may have formed by flow of impact melt.
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It is thought by some to have been created as seismic waves from the impact converged on the opposite side of the planet. Alternatively, it has been suggested that this terrain formed as a result of the convergence of ejecta at this basin's antipode. This hypothetical impact is also believed to have triggered volcanic activity on Mercury, resulting in the formation of smooth plains. Surrounding Caloris is a series of geologic formations thought to have been produced by the basin's ejecta, collectively called the Caloris Group.
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Hilly and hummocky remnants resembling basin deposits and ejecta protrude above the gently sloping basin wall. They extend southwest and north of the basin beyond a much subdued, low, barely perceptible rim crest for a distance of one-half to one-third of the basin radius. Goethe is older than the smooth plains material by which its wall, rim crest, and most of its ejecta were partly buried. The Goethe impact basin may be older than some intercrater plains material and large craters nearby.
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Fridman is the remains of a lunar impact crater on the far side of the Moon. It lies due south of the huge walled plain Hertzsprung, and is attached to the northeastern rim of the crater Ioffe. This crater lies in the southern part of the ejecta blanket that encircles Hertzsprung, and in the west-northwestern part of the huge ejecta blanket surrounding the Mare Orientale impact basin. The outer rim of this crater is heavily damaged, with a number of smaller craters lying across the sides.
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A small unnamed basin at –48°, 136° may also have formed in this time interval, but its age is uncertain due to its partial burial by ejecta from crater Delacroix (–44°, 129°). The effects of the Caloris impact on the map area are not immediately apparent. No Caloris ejecta are evident, and most structural trends appear to be unrelated to this impact. However, near the west border of the map are two groups of large, overlapping craters centered at –31°, 183° and –49°, 182°.
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Smithtown, N.Y. The Argyre quadrangle covers the area from 0° to 60° west longitude and from 30° to 65° south latitude on Mars. It contains Galle crater, which resembles a smiley face and the Argyre basin, a giant impact crater. Research published in the journal Icarus has found pits in Hale Crater that are caused by hot ejecta falling on ground containing ice. The pits are formed by heat forming steam that rushes out from groups of pits simultaneously, thereby blowing away from the pit ejecta.
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These minerals were formed in the ejecta when supernovae exploded or low- to intermediate- sized stars expelled their outer envelopes late in their lives. Graphite may be the second or third oldest mineral in the Universe.
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Much of the southern section of the floor has been covered by ejecta from nearby impacts. The northern half of the floor, however, is much more smooth and nearly featureless except for a few minor impacts.
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Le Verrier (right). The mountain on the horizon at left is Promontorium Laplace, about 180 km beyond Helicon. Note that Helicon's ejecta is buried by the mare lava, but Le Verrier's is not. From Apollo 15.
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Coarsely lineated ejecta blankets from Beethoven and Raphael basins dominate the southern part of the map area. The crater wall of Beethoven is buried by its ejecta blanket and by plains materials. Although the ejecta blankets from both basins are extensive, they are highly asymmetrical and deeply embayed in places by intercrater plains and younger plains units. These embayment relations, together with the discontinuous and subdued appearance of the rim crests and interior walls of the basins, suggest that they are relatively old impact structures. Morphologic appearances may be misleading on Mercury, however, because of the planet’s high temperature and gravity field compared with, for example, those of the Moon. Both of these conditions may promote, particularly on large structures, more rapid isostatic adjustments that would be expressed by subdued topography and the premature “aging” of once-large topographic features.
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It is mostly dependent upon the type of propellant used, but may depend slightly on other things such as the ratio of the length of the barrel to its radius. Muzzle devices can reduce the recoil impulse by altering the pattern of gas expansion. For instance, muzzle brakes primarily works by diverting some of the gas ejecta towards the sides, increasing the lateral blast intensity (hence louder to the sides) but reducing the thrust from the forward-projection (thus less recoil). Similarly, recoil compensators divert the gas ejecta mostly upwards to counteract the muzzle rise.
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These formed about a billion secondary craters 10 m in size up to 3500 km away from the primary impact. It is possible that some of these fragments from the impact made it to Earth to become shergottites, a form of Martian meteorite. Research published in the journal Icarus has found pits in Zunil Crater that are caused by hot ejecta falling on ground containing ice. The pits are formed by heat forming steam that rushes out from groups of pits simultaneously, thereby blowing away from the pit ejecta.
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"Afraid of the Dark" is a song released by American synthpop duo Young Ejecta, consisting of Leanne Macomber and Joel Ford, under the name Ejecta. Written by Macomber and produced by Ford, the song was released in September 2013 as the second single from the duo's debut studio album Dominae (2013). The four- minute track lyrically addresses "someone, broken by love, who is building up strength to protect themselves in future", as stated by Polari Magazine. It earned positive reviews from music critics upon release and was played on the show The Vampire Diaries.
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Alternatively, they may be associated with crater Verdi ejecta or with lineated and secondary-crater ejecta that flare southeastward from an unnamed crater north of and adjacent to the crater Nizami. Another morphologic feature that may be related to the Caloris Basin event consists of grooves on intercrater plains material and on the southwest- facing walls of craters such as Mansart. These grooves are as much as several kilometers long and several hundred meters wide. The direction of elongation of many small secondary craters also suggests an origin related to the Caloris event.
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Hapke and others have suggested that the dark-albedo materials associated with the Tolstoj Basin margins are distinctly bluer than the surrounding terrain, whereas the plains filling the interior are distinctly redder. Despite Tolstoj’s great age and its embayment by the ancient inter- crater plains, it retains an extensive and remarkably well preserved, radially lineated ejecta blanket around two-thirds of its circumference. The ejecta tends to be blocky and only weakly lineated between the inner and outer rings. Radial lineations with a slight swirly pattern are best seen on the southwest side of Tolstoj.
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Many of these lineaments may be faint secondary-crater chains or gouges; others may represent traces of an ancestral structural pattern that partly controlled the excavation of the craters and basin. The lineaments may have been enhanced or preserved by the gentle upwarping of this region of Tolstoj ejecta discussed above. The largest lineament, which marks the northwest limit of recognizable Tolstoj ejecta, is a subdued scarp some 450 km long. Rejuvenation of earlier faults or fractures by subsequent impacts probably occurred throughout the history of the planet.
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The Tolstoj basin is used to define a time-stratigraphic system, the Tosltojan system, with the age of around 4.0–3.9 billion years. The older system (< 4.0 billion years) is called pre-Tosltojan, while the younger is called Calorian (3.9–3.5 billion years). Despite Tolstoj’s great age and its embayment by the ancient inter-crater plains, it retains an extensive and remarkably well preserved, radially lineated ejecta blanket around two-thirds of its circumference. The ejecta tends to be blocky and only weakly lineated between the inner and outer rings.
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As first noted by Gault and others, the continuous ejecta blankets and secondary crater fields surrounding mercurian craters are smaller than their lunar counterparts, and the boundary between the two features is much less distinct. As a consequence, continuous and discontinuous ejecta are mapped together in the Bach region as “radial facies.” With this exception, the morphological elements of mercurian craters are virtually identical with those on the Moon. Therefore, all of the craters within the Bach region are probably the result of impact by meteorites, small planetesimals, and possibly comets.
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By comparing the reflectance spectra of the angrites to that of several main belt asteroids, two potential parent bodies have been identified: 289 Nenetta and 3819 Robinson. Other scientists have suggested that angrites could represent ejecta from Mercury.
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It had long been estimated that the top centimeter of the lunar surface is overturned every 10 million years. However a 2016 analysis by the LRO satellite of impact ejecta coverage puts the figure closer to 80,000 years.
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Most fire or volcanic eruption induced whirlwinds are not tornadic vortices, however, on rare occasion circulations with large wildfires, conflagrations, or ejecta do reach an ambient cloud base, and in extremely rare cases pyrocumulonimbus with tornadic mesocyclones have been observed.
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Many mercurian secondaries are well preserved and have sharp, unrounded rims. This morphology is probably a consequence of the stronger mercurian gravity, relative to the Moon, that produces higher impact velocities for crater ejecta on the mercurian surface (Scott, 1977).
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The southern end of the rim has been covered by the ejecta from Aristillus. Along the eastern inner wall and rim is an unusual narrow ribbon of dark material. Detail map of Mare Imbrium's features. Aristillus is the feature marked "E".
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Apollo 13 was originally scheduled to land in the Fra Mauro highlands, but was unable due to an in-flight technical failure. Fra Mauro is thought to have been formed from ejecta, or debris, from the impact which formed Mare Imbrium. During Apollo 14, the crew members sampled ejecta from Cone crater, a feature close in proximity to the immediate landing site of the mission, which provided insight into the composition of material deep inside the formation. Data from the mission has helped to determine the approximate age of Mare Imbrium, suggesting that it is no more than about 4.25 billion years old.
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Fra Mauro is a widespread hilly geological area covering large portions of the lunar surface around Mare Imbrium, and is thought to be composed of ejecta from the impact which formed Imbrium. The area is primarily composed of relatively low ridges and hills, between which exist undulating valleys. Much of the ejecta blanket from the Imbrium impact is covered with debris from younger impacts and material churned up by possible moonquakes. Debris found in the formation may have originated from deep beneath the original crust, and samples collected there could give insight into the geologic history of the Moon.
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The crater was formed about 32,000 years ago when groundwater seeping down into the earth came into contact with magma rising from beneath the crust. The hot magma instantly turned the water to steam, and the sudden high pressure triggered a phreato-magmatic explosion, blowing a huge hole in the ground, and blasting out rocks, magmatic material and ash, forming the crater. Ejecta was spread out to a distance of about from the crater over what is now the desert floor. The crater rim is higher than the surrounding desert and shows layers of rock built up from the ejecta.
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A well- known example of a key bed is the global layer of iridium-rich impact ejecta that marks the Cretaceous–Paleogene boundary (K–T boundary). Palynology, the study of fossil pollens and spores, routinely works out the stratigraphy of rocks by comparing pollen and spore assemblages with those of well-known layers—a tool frequently used by petroleum exploration companies in the search for new fields. The fossilised teeth or elements of conodonts are an equally useful tool. The ejecta from volcanoes and bolide impacts create useful markers, as different volcanic eruptions and impacts produce beds with distinctive compositions.
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Also if the proposed Borealis basin is a depression created by an impact, it would be the largest impact crater known in the Solar System. An object that large could have hit Mars sometime during the process of the Solar System accretion. It is expected that an impact of such magnitude would have produced an ejecta blanket that should be found in areas around the lowland and generate enough heat to form volcanoes. However, if the impact occurred around 4.5 Ga (billion years ago), erosion could explain the absence of the ejecta blanket but could not explain the absence of volcanoes.
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The unit appears to be gradational laterally eastward with plains and terra material, undivided, and vertically with intermediate plains material. The intercrater plains material is probably about the same age as the ejecta blanket around Beethoven basin: both units have a high crater density. That the plains unit is younger than Beethoven may be indicated in some areas where the basin’s ejecta blanket appears to be partly obscured by the overlap or embayment of plains material. Spudis and Prosser (1984) have suggested that Beethoven may possibly be late c3 in age or as old as early c2.
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Earlier flows extend to the north and west. The coarse ejecta exposed around the summit includes red and green olivine and megacrysts of high-temperature (some of the largest known Victorian examples) and orthoclase (to 7 cm long) and augite (over 9 cm long). Lumps of Ordovician sedimentary and granitic bedrock also occur in the ejecta and small basalt blocks contain cores of crazed quartz. On the western slope is the parasitic scoria mound known as "Lady Franklin". The volcanic eruptions may have been witnessed by members of the Dja Dja Wurrung native Aboriginal tribe who called this country the ‘smoking grounds’.
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The plains also embay the Caloris Formation and account in particular for the skeletal map pattern of the Van Eyck Formation. The ubiquitous distribution of smooth plains in topographically low regions supports the hypothesis that these materials were deposited in a fluid or semifluid state as basin ejecta or volcanic flows. The plains are thought to be slightly younger but dose to the same age as the Caloris Basin materials; thus parts of the plains are probably Caloris ejecta, either impact melt or very fluid debris flows. No obvious secondary craters from Caloris have been recognized on the smooth plains.
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The thrust block partly overrides a tilted rim graben that has down-dropped about and moved toward the crater. Overlying this graben is a layer of breccia which is apparently the remains of an ejecta blanket that once surrounded the crater. Post-crater erosion removed the ejecta, except for that overlying the graben, and lowered the regional ground surface less than 30 m. Within a few million years of the cratering event the entire structure was covered with shale deposits from the early Late Devonian Chattanooga Sea, creating one of the best-preserved ancient impact structures presently known.
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Dominae is the debut studio album of American electronic duo Ejecta (now Young Ejecta), consisting of Neon Indian singer Leanne Macomber and producer Joel Ford of Ford & Lopatin. The record consists of ten retro 1980s-style synthpop songs dealing with love, death and early adulthood struggles. Taking seven years to write, it was recorded in New York and Texas, beginning in the summer of 2012 and lasting 14 months, and released on November 4, 2013 by Driftless Recordings, Happy Death and Copyright Control. All the tracks were written by Macomber and produced by Ford, who also did co-writing.
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It occurs as small patches within the smooth plains unit that fills the crater Pushkin. Smooth plains material embays the ejecta blanket of a c3 crater on Pushkin's rim at lat 66° S, long 28° (FDS 27402) and fills the interior and part of the outer- ring area of Bach. The distribution of these two youngest plains units may indicate that the smooth plains material as mapped is nothing more than a thin, discontinuous layer of very smooth plains material that mantles the older units. In this respect, it is similar to the lunar Cayley Formation, which is probably basin ejecta.
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In kimberlite pipes, the eruption ejects a column of overlying material directly over the magma column, and does not form a large above-ground elevation as typical volcanoes do; instead, a low ring of ejecta known as a tuff ring forms around a bowl-shaped depression over the subterranean column of magma. Over time, the tuff ring may erode back into the bowl, leveling out the depression by filling it with washed-back ejecta. Kimberlite pipes are the source of most of the world's commercial diamond production, and also contain other precious gemstones and semi-precious stones, such as garnets, spinels, and peridot.
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A new class of Martian impact craters have been discovered by Northern Arizona University scientist Prof Nadine Barlow and Dr Joseph Boyce from the University of Hawaii in Oct 2013. They have termed it as ‘low-aspect-ratio layered ejecta (LARLE) craters’. Prof Nadine Barlow, a scientist Northern Arizona University described this class of craters with “thin-layered outer deposit” surpassing “the typical range of ejecta”. “The combination helps vaporize the materials and create a base flow surge. The low aspect ratio refers to how thin the deposits are relative to the area they cover,” Prof Barlow said.
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The ejecta is flat along its whole area, like a pancake. Under higher resolutions it resembles a double-layer crater that has degraded. These craters are found in the same latitudes as double-layer craters (40–65 degrees).Mouginis-Mark, P. 1979.
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The heavy rainfall also accompanying a violent typhoon carried down disintegrated fragmental ejecta, burying plantations and whole villages. In 1825, the event was repeated in Cagsawa killing 1,500 people.Maso, Saderra (1902). "Seismic and Volcanic Centers of the Philippine Archipelago", pp. 13–14.
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It is surrounded by streaks of ejecta that have a higher albedo than the nearby maria. This nebulous skirt of light-hued material makes this feature very prominent under a high Sun, and it is one of the brightest sites on the Moon.
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Estimates of the total mass of the nebula are important for estimating the mass of the supernova's progenitor star. The amount of matter contained in the Crab Nebula's filaments (ejecta mass of ionized and neutral gas; mostly helium) is estimated to be .
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A small crater with a relatively high albedo lies along the inner wall to the northeast, and is surrounded by a small, bright skirt of ejecta. The interior floor is nearly featureless, with only a few indistinct small crater rims marking the surface.
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Particularly notable events that are preserved in the rock record of the Adelaide Superbasin are the two Neoproterozoic Snowball Earth events (the Sturtian and Marinoan Glaciations), the Neoproterozoic Oxygenation Event, the Ediacaran Acraman bollide ejecta layer and the rise of Ediacaran Fauna.
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Much of the eastern rim of the crater is overlaid by this ejecta, and only a portion of the western rim near Schluter remains well-formed. The interior floor has likewise been modified. There is a small crater on the floor near the northeastern rim.
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The inner wall slopes down without terraces to the ejecta along the base. The interior floor is relatively featureless and is free of notable impacts or ridges. This crater was previously designated Hercules A, a satellite crater of Hercules, before being renamed by the IAU.
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Physical and chemical characteristics of volcanic ash are primarily controlled by the style of volcanic eruption. Volcanoes display a range of eruption styles which are controlled by magma chemistry, crystal content, temperature and dissolved gases of the erupting magma and can be classified using the volcanic explosivity index (VEI). Effusive eruptions (VEI 1) of basaltic composition produce <105 m3 of ejecta, whereas extremely explosive eruptions (VEI 5+) of rhyolitic and dacitic composition can inject large quantities (>109 m3) of ejecta into the atmosphere. Another parameter controlling the amount of ash produced is the duration of the eruption: the longer the eruption is sustained, the more ash will be produced.
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The low density of small craters in the oldest class, c1, results from their destruction by impacts and obscuration by ejecta and volcanic material over a long period of mercurian history. The intercrater plains and younger plains materials probably have mixed origins, and they consist of both volcanic and impact ejecta-related deposits. The plains materials accumulated mostly in low-lying areas and have buried or partly buried older craters and surfaces. Their relative ages and thicknesses are reflected by the number of craters visible on their surfaces: where crater densities are high, the plains material is relatively old or thin; low crater densities indicate relatively thick, young deposits.
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Ballistic pendulum (1911) The ballistic pendulum was invented in 1742 by English mathematician Benjamin Robins (1707–1751), and published in his book New Principles of Gunnery, which revolutionized the science of ballistics, as it provided the first way to accurately measure the velocity of a bullet. Robins used the ballistic pendulum to measure projectile velocity in two ways. The first was to attach the gun to the pendulum, and measure the recoil. Since the momentum of the gun is equal to the momentum of the ejecta, and since the projectile was (in those experiments) the large majority of the mass of the ejecta, the velocity of the bullet could be approximated.
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About 60 percent of the mapped area consists of tracts of planar surfaces having a variety of small-scale textures. These tracts range in size from a few square kilometers within craters to areas larger than 10,000 km2 that surround and separate large craters: the so-called “intercrater plains”. The origin of the plains material is uncertain. Strom and others, Trask and Strom, Strom (1977), and Leake (1982) presented arguments in favor of volcanism, whereas Wilhelms and Oberbeck and others (1977) argued for an impact-related origin through processes similar to those responsible for the lunar Cayley Plains (fluidized ejecta sheets or ballistically deposited secondary-crater ejecta).
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The two proposed origins for this plains unit, as volcanic or basin-ejecta material, cannot be unambiguously resolved by geologic relations in the Bach region. However, a volcanic origin is favored because of (1) the widespread distribution of the plains material throughout the imaged regions of Mercury, (2) the apparent lack of source basins large enough to supply such great amounts of impact melt, and (3) the restricted ballistic range of ejecta on Mercury. The intermediate plains material is concentrated mostly in the northeastern part of the Bach region. It is similar in morphology to intercrater plains material but has a lower density of small craters.
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Lightcurve analysis gave a rotation period of 10 hours with a brightness amplitude of 0.15 magnitude (). The team of astronomers also ruled out that Christophedumas might be an Escaping Ejecta Binary (EEB), that are thought to be created by fragments ejected from a disruptive impact event.
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Kimberlitic rocks from the Buffalo Head Hills. Display by Alberta Geological Survey.The BHH kimberlite pipes cover areas ranging from one to . They represent maar-style volcanoes which have a vertical-walled volcanic crater of explosive origin, surrounded by a low rim of ejecta and filled with water.
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MESSENGER image of secondary craters surrounding a primary impact site. Secondary craters are impact craters formed by the ejecta that was thrown out of a larger crater. They sometimes form radial crater chains. In addition, secondary craters are often seen as clusters or rays surrounding primary craters.
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The outer rim of Pikel'ner is well-defined with little erosion, giving it the appearance of a relatively young feature. The interior floor is somewhat uneven, possibly due to deposits of ejecta or fall- back material. It is free of impacts of note within the interior.
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Bridge crater is located within Hadley Rille, also known as the Hadley-Apennine region, and its ejecta indeed forms a bridge of sorts across the rille. It lies at the base of Mons Hadley Delta and is approximately 4 km southwest of the Apollo 15 landing point.
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Viking Orbiter 1 mosaic of northern Calahorra crater and its ejecta Calahorra is an impact crater on Mars. The crater was named after the town of Calahorra, Spain, by IAU in 1997. Calahorra is an example of a rampart crater. Craters of this type are unique to Mars.
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Close-up photographs of this crater by Lunar Orbiter 5 show many large blocks lying along the sloping outer rampart. The surface near the crater is hummocky from the deposited ejecta. The crater is otherwise undistinguished. The vicinity of Censorinus was once considered for an early Apollo landing site.
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Image covers an area 32 km across.Rays appear at visible, and in some cases infrared wavelengths, when ejecta are made of material with different reflectivity (i.e., albedo) or thermal properties from the surface on which they are deposited. Typically, visible rays have a higher albedo than the surrounding surface.
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Sterling Publishing Co.. . The inner walls of the crater slope down to a relatively level interior floor. This bottom floor is nearly featureless except for a few tiny craterlets scattered across the surface. In the southeast, the ejecta from Nearch A has produced a slightly more irregular region.
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The tiny craterlet Encke N lies across the western rim. The floor is somewhat uneven, and is covered in ray material from the nearby Kepler. The high albedo of this ejecta makes Encke a bright feature when the Sun is at a high elevation over the lunar surface.
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The remaining rim is worn and eroded, with a number of small craterlets along the edge and inner wall. The western interior floor is relatively level, but is marked by ejecta and secondary cratering from Antoniadi. If the crater ever possessed a central ridge, it may now be buried.
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The outer rings of impact deposits around Lofn are made from the dark material, which was excavated first and accelerated to a high speed. After that the light water rich material was excavated from the depth, but with a lower speed forming the bright inner ring of ejecta.
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It usually takes days for the solar plasma ejecta to reach Earth.Menzel, Whipple, and de Vaucouleurs, "Survey of the Universe", 1970 Flares also occur on other stars, where the term stellar flare applies. High-energy particles, which may be relativistic, can arrive almost simultaneously with the electromagnetic radiations.
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Rocks at the summit have ages of between 260,000 and 10,000 years. Individual eruptions have been dated to 10,000±20,000, 80,000±15,000, 260,000±60,000 and 15,000±35,000 years ago. Highly inprecise ages of late Pleistocene to Holocene age have been obtained from the ejecta layer on the summit.
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O'Keefe later suggested that the meteors, which he referred to as the "Cyrillids", could have in fact represented the last remnant of a circumterrestrial ring, formed from the ejecta of a postulated lunar volcano. This theory was a development of O'Keefe's unusual hypothesis on the origin of tektites.
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This rock, identified as Sayh al Uhaymir 169, is believed to have originated from the Moon. It was ejected from the surface during an impact that occurred less than 340,000 years in the past. Scientists now think that the rock originated from the crater ejecta blanket surrounding Lalande.
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The impact of a large meteoroid can lead to the loss of atmosphere. If a collision is sufficiently energetic, it is possible for ejecta, including atmospheric molecules, to reach escape velocity. In order to have a significant effect on atmospheric escape, the radius of the impacting body must be larger than the scale height. The projectile can impart momentum, and thereby facilitate escape of the atmosphere, in three main ways: (a) the meteoroid heats and accelerates the gas it encounters as it travels through the atmosphere, (b) solid ejecta from the impact crater heat atmospheric particles through drag as they are ejected, and (c) the impact creates vapor which expands away from the surface.
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Most material ejected from the crater is deposited within a few crater radii, but a small fraction may travel large distances at high velocity, and in large impacts it may exceed escape velocity and leave the impacted planet or moon entirely. The majority of the fastest material is ejected from close to the center of impact, and the slowest material is ejected close to the rim at low velocities to form an overturned coherent flap of ejecta immediately outside the rim. As ejecta escapes from the growing crater, it forms an expanding curtain in the shape of an inverted cone. The trajectory of individual particles within the curtain is thought to be largely ballistic.
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Continuous areas and narrow filaments of light-gray ejecta extend from the crater across the dark mare surface through 270°, but are entirely absent in the southern 90° sector. Within the crater, dark material occurs on the southern crater wall while the remaining walls are bright. This crater probably resulted from the impact of a projectile traveling from south to north along an oblique trajectory. Its pattern of ejecta distribution is similar to that of small craters produced by the impact of missiles along oblique trajectories at the White Sands Missile Range, NM. Some observers postulate that the dark material is a talus deposit of mare material that has fallen into the crater.
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Oblique Lunar Orbiter 5 image Another view of Wan-Hoo also from Lunar Orbiter 5 Wan-Hoo is a lunar impact crater that is located on the Moon's far side, and it cannot be seen directly from the Earth. It lies to the southwest of the huge walled plain Hertzsprung, within the outer skirt of ejecta. Just to the south-southwest of Wan-Hoo is the larger crater Paschen, and a little over two crater diameters to the northwest is Sechenov. Like much of the surrounding terrain, this crater has been modified by the ejecta from Hertzsprung, and material from that impact encroaches along the inner walls and interior of Wan-Hoo.
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The northern half of the interior floor is level and marked only by a few very tiny craterlets. The southern floor is more irregular due to the overlaying ejecta from Neumayer and Boussingault, and is marked by a pair of tiny craters in the southeast. There is no central peak.
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Researchers have suggested that the rain may have been initiated by impacts. Some parts of the crater display a high concentration of closely spaced pits. Pits show little or no evidence of rims or ejecta. The pits are so close to each other that adjacent pits often share the same wall.
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From left to right, shows the timeline of a mass impacting a body, ejecta propagating from the initial impact, shock wave motion and the resulting cratered surface. The right most rectangle features arrows, which express the location at which secondary craters will form outside of or away from the impact center.
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Oblique view from Apollo 15 Lohse is a lunar impact crater on the eastern edge of Mare Fecunditatis. It is attached to the north rim of the larger crater Vendelinus. To the north is the prominent Langrenus. The interior of Lohse is rough, being partially covered by ejecta from Langrenus.
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The third stays behind. Soon the ejecta cloud causes a sandstorm, suffocating the two Charonosaurus alive. The pair of Saurornithoides survive by hiding behind their prey, while the third Charonosaurus remains in the cave. A day passes, and the Saurornithoides return to the watering hole, where the last Charonosaurus is drinking.
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MESSENGER NAC mosaic of Murasaki crater. Much of Murasaki is overlain by ejecta, impact melt, and secondary craters from the Kuiper impact. Murasaki is a crater on Mercury located at 12 S, 31 W. It is 132 km in diameter. It was named after 10th-11th century Japanese writer Murasaki Shikibu.
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If the crater once possessed a central peak, it is now buried by the ejecta from Drygalski. Only a section of the interior floor near the southwest rim is flat, being marked only by tiny craterlets. This crater was previously designated Drygalski Q before being assigned a name by the IAU.
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The Catena Leuschner is a crater chain formation that begins at the northern outer rim of Leuschner and runs to the northwest towards the crater Kolhörster. This feature is radial to the Mare Orientale impact, and was likely caused by larger chunks of ejecta during the formation of that feature.
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Tacquet is a small, bowl-shaped crater that lies near the southern edge of Mare Serenitatis, in the northeast part of the Moon. The surface near the crater is marked by high-albedo ejecta. To the west is a system of rilles designated the Rimae Menelaus. Its diameter is 6.4 km.
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The emission or ejecta hypothesis is considered less likely because if it were the case all the peaks should share equal separation, which they do not.Li et al., 2003 p. 19 SN 2002cx has absorption and emission lines between 6400 Å and 7000 Å that are unique among previously discovered type Ia supernovae.
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It has not had a recorded eruption, though numerous deposits of lava flows and other ejecta on the southern and eastern flanks and a submarine deposit to the north of the summit which extends for have very little erosion, making it likely that Segula has erupted in the last few hundred years.
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Color image of Abedin Abedin is a crater on Mercury. It is named after the Bangladeshi painter Zainul Abedin. It exhibits a complex crater structure with a smooth floor, wall terraces, and a central peak complex. The chains of smaller craters surrounding Abedin are secondary craters formed by ejecta from the initial impact.
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Other surface features include landslides, gravitational taluses and ejecta blocks up to 300 m in size. The landslides and corresponding rock outcrops are correlated with variations of albedo, being generally brighter. The two oldest regions are Achaia and Noricum. The former is a remarkably flat area with a lot of impact craters.
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Lithogenic silica (LSi) is silica (SiO2) derived from terrigenous rock (Igneous, metamorphic, and sedimentary), lithogenic sediments composed of the detritus of pre-existing rock, volcanic ejecta, extraterrestrial material, and minerals such silicate. Silica is the most abundant compound in the earth's crust (59%) and the main component of almost every rock (>95%).
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AGU, 85(47), Fall Meet. Suppl., Abstract B33C-0269. Abstract # A crater of the purported size would have produced a widespread layer of ejecta, but no such eject is evident at the nearest Permian-Triassic boundary sites in Australia.Wignall P., Thomas B., Willink R., Watling J., Becker L., Poreda R.J. & Pope K.O. 2004.
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The plan was to visit both Phobos and Deimos, and launch projectiles at the satellites. The probe would collect the ejecta as it performed a slow flyby. These samples would be returned to Earth for study three years later. Ultimately, NASA rejected this proposal in favor of MESSENGER, a probe to Mercury.
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Craters are ubiquitous features of the mercurian surface. For the purpose of mapping, a fivefold morphologic classification of craters (fig. 10 in McCauley et al., 1981) is the basis for determining their relative ages. The youngest craters (c5) have sharp rim crests, textured ejecta blankets, and a well-defined field of secondary craters.
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For primary impacts, based on geometry, the most probable impact angle is 45° between two objects, and the distribution falls off rapidly outside of the range 30° - 60°. It is observed that impact angle has little effect on the shape of primary craters, except in the case of low angle impacts, where the resulting crater shape becomes less circular and more elliptical. The primary impact angle is much more influential on the morphology (shape) of secondary impacts. Experiments conducted from lunar craters suggests that the ejection angle is at its highest for the early-stage ejecta, that which is ejected from the primary impact at its earliest moments, and that the ejection angle decreases with time for the late-stage ejecta.
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These craters have been included in a separate facies of the Van Eyck Formation because of their regional stratigraphic significance. It is noteworthy that this lineated terrain occurs near the foot of the Caloris Montes, whereas similar units of the Imbrium Basin on the Moon occur farther from the basin rim. Such a difference in extent is to be expected because mercurian gravity is two and a half times greater than lunar gravity, and ejecta would fall closer to its source than ejecta from a similar-size basin on the Moon.Gault, D. E., Guest, J. E., Murray, J. B., Dzurisin, Daniel, and Malin, M. C., 1975, Some comparisons of impact craters on Mercury and the Moon: Journal of Geophysical Research, v.
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They are thought to be either volcanic or a facies of ballistic ejecta (Oberbeck and others, 1977). The interpretation favored here is that large parts of these smooth plains are of volcanic origin, because (1) they are distributed regionally and have no obvious source for ballistic deposition; (2) large tracts are confined within basin depositional environments, analogous to the lunar maria; (3) indirect evidence elsewhere on Mercury exists for volcanic modification of impact craters (Schultz, 1977); and (4) possible volcanic collapse craters are associated with plains-filled craters (–61°, 161° and –57°, 102°). Parts of smooth plains deposits may be a complex mix of overlapping crater ejecta. A very smooth plains unit occurs only as floor material in younger c4 and c5 craters.
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"Young Ejecta: Your Planet EP Review". Paste, Adrian Spinelli, January 27, 2015 Heather Phares of Allmusic describes the band's synthpop sound as "gauzy". In August 2019, their song “Welcome to Love” was chosen as the outro audio of Netflix’s “Orange is the New Black” on the 10th episode of the 7th and final season.
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22, 2013 The research postulated the crater was formed by the volcano's caldera collapsing, rather than from an impact. Some of reasons for suspecting that Eden Patera is a collapsed caldera not an impact crater are its irregular shape, an apparent lack of a raised rim or central peak, and lack of impact ejecta.
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The ejecta are mainly observed to the north and northeast from the basin. The interior of Rembrandt includes two terrain types: hummocky terrain and smooth plains. The former occupies a part of the basin's floor near its northern margin forming an incomplete ring about wide. The latter fill much of the interior of Rembrandt.
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The probe's spectrometer instrument detected dust particles finer than human hair, and discovered the presence of silicates, carbonates, smectite, metal sulfides (such as fool's gold), amorphous carbon and polycyclic aromatic hydrocarbons. Water ice was detected in the ejecta. The water ice came from 1 meter below the surface crust (the devolatized layer around the nucleus).
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The rim edge is worn and irregular, and ejecta material has been carried into the northern interior floor. There are a pair of lower albedo patches in the southern interior, which are typically characteristic of basaltic-lava deposits. A few low ridges lie about the center and also to the east of the midpoint.
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Pasadena, CA: NASA Jet Propulsion Laboratory. NASA-CR-194340 JPL Publication 93-24: 57–73. 1993.; cited in This process is manifest in the ejecta of impact craters expelled onto the surface of Venus. The material ejected during a meteorite impact is lifted to the atmosphere, where winds transport the material toward the west.
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The remainder of the rim is irregular and less distinct. This condition may have been created by the ejecta from the Mare Orientale impact to the south. A pair of small craters lies along the northwestern rim. Less than two crater diameters to the south of Elvey is the impact site of a small crater.
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The remnant is evolving rapidly. By 2009 its temperature had increased a bit (since 2005) to 3,270 K and its luminosity was 15,000 times solar (), but its radius had decreased to 380 times that of the Sun () although the ejecta continues to expand. The opaque ejected dust cloud has completely engulfed a B-type companion.
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In February 2020, Chinese astronomers reported, for the first time, a high- resolution image of a lunar ejecta sequence, and, as well, direct analysis of its internal architecture. These were based on observations made by the Lunar Penetrating Radar (LPR) on board the Yutu-2 rover while studying the far side of the Moon.
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The planet Mars LARLE crater, as seen by CTX LARLE layer that is composed of fine-grained material is labeled. It may be eroded away and a pedestal crater will remain.Barlow, N., J. Boyce, C. Cornwall. Martian Low-Aspect-Ratio Layered Ejecta (LARLE) craters: Distribution, characteristics, and relationship to pedestal craters. Icarus:239, 186-200.
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To the east is the rounded Sosigenes. The interior floor of Julius Caesar is relatively level, especially in the southwest half. The northern half of the interior has a lower albedo (darker) than the south. Most likely the floor has been covered or modified by ejecta from the impact that created the Imbrium basin.
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Kepler is most notable for the prominent ray system that covers the surrounding mare. The rays extend for well over 300 kilometers, overlapping the rays from other craters. Kepler has a small rampart of ejecta surrounding the exterior of its high rim. The outer wall is not quite circular, and possesses a slightly polygonal form.
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Just to the northwest of this grouping is a bright patch of high-albedo material. Sections of the floor along the north- northwestern side have a lower albedo than elsewhere, usually an indication of basaltic-lava flows similar to what fills the lunar maria. The extent of this patch may actually be larger, but covered with higher-albedo ejecta.
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SN 2016aps (also known as PS16aqy and AT2016aps) is the brightest (as of April 2020) supernova explosion ever recorded. In addition to the sheer amount of energy released, an unusually large amount of the energy was released in the form of radiation, probably due to the interaction of the supernova ejecta and a previously lost gas shell.
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These impacts have distorted the shape of the crater, and have nearly obliterated the southern rim. Ejecta from Longomontanus overlies part of the southern floor. The satellite crater Montanari D lies across the western rim, and covers part of the interior floor. The northern part of the floor is more regular and featureless than the south.
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Hecataeus is a worn and eroded walled plain with wide inner walls. Its northern part overlies half of Hecataeus K, a fairly substantial crater. Along the southern rim, the outer rampart of ejecta from Humboldt forms a rugged interior surface across the southern floor. Several small, bowl-shaped craters lay across the eastern rim and inner wall.
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Melosh, H.J., 1989, Impact cratering: A geologic process: New York, Oxford University Press, 245 p. This describes impacts on solid surfaces. Impacts on porous surfaces, such as that of Hyperion, may produce internal compression without ejecta, punching a hole in the surface without filling in nearby craters. This may explain the 'sponge-like' appearance of that moon.
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The crater has a dark floor and is surrounded by a system of bright rays, which are ice ejecta deposited during the impact event. The nature of the dark material on the floor is unknown, but it may have erupted from the depth through cryovolcanism. The crater was first imaged by the Voyager 2 spacecraft in January 1986.
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This material appears to consist primarily of material that is ejected from the surfaces of Jupiter's four small inner satellites by meteorite impacts. It is easy for the impact ejecta to be lost from the satellites into space because the satellites' surfaces lie fairly close to the edge of their Roche spheres due to their low density.
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The outer ramparts display a generally radial structure of hillocks through the extensive blanket of ejecta. The crater floor is uneven and covered in hilly ripples. Aristoteles does possess small central peaks but they are somewhat offset to the south. The interior floor appears to have been filled with a layer of material partially burying these projections.
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Map of the Henbury craters in Australia. The dashed line indicates the limit of ejecta from the larger craters. The Henbury crater field lies at the crossroads of several Aboriginal language groups, including Arrernte, Luritja, Pitjantjatjarra, and Yankunytjatjara. It is considered a sacred site to the Arrernte people and would have formed during human habitation of the area.
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It has not been significantly eroded, and is generally unremarkable. The nearest craters of note are Graff to the south-southeast and Focas to the north-northwest. The surrounding area is of note for the tumultuous terrain created by the ejecta from Mare Imbrium. The satellite crater formerly known as Drude S was renamed Heyrovský by the IAU.
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Ronald Greeley, Planetary Landscapes, 1985, Boston, Allen & Unwin He coined the term sculpture for a pattern of radial ridges surrounding Mare Imbrium on the moon, and correctly interpreted them in 1893 as ejecta from a giant impact.Gilbert, Grove Karl. The moon's face, a study of the origin of its features. Washington, Philosophical Society of Washington, 1893.
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The Nervo Formation was originally designated the intermontane plains by Trask and Guest and has been interpreted by them as fallback ejecta, an interpretation that seems to explain its distribution pattern and relative roughness as well as the fact that it is generally perched above the smooth plains that encompass Caloris. The Nervo formation is named after Nervo crater.
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262, p.36. Remnant ejecta blankets around parts of the Beethoven and Raphael basins are subdued in appearance and their margins poorly defined in places. However, where they can be recognized, these extensive aprons allow a generalized regional stratigraphic sequence to be determined. A third basin, extremely subdued but probable, is centered at latitude 0°, longitude 130°.
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325, 331–336, 355–362. Also called Phaethontias. It contains the southern part of Caloris Planitia, which is the largest and best preserved basin seen by Mariner 10. This basin, about 1550 km in diameter, is surrounded by a discontinuous annulus of ejecta deposits of the Caloris Group that are embayed and covered by broad expanses of smooth plains.
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Gula is a crater on Ganymede. It is a fresh crater with a distinctive central peak. It is about 40 km (25 miles) in diameter. A characteristic feature of both Gula and its southern neighbor Achelous, almost identical in size, is the "pedestal" − an outward-facing, relatively gently sloped scarp that terminates the continuous ejecta blanket.
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Ganymede's carbon dioxide gas was probably depleted in the past. A sharp boundary divides the ancient dark terrain of Nicholson Regio from the younger, finely striated bright terrain of Harpagia Sulcus. Enhanced-color Galileo spacecraft image of Ganymede's trailing hemisphere. The crater Tashmetum's prominent rays are at lower right, and the large ejecta field of Hershef at upper right.
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Dickinson crater is located at 74.6 degrees north latitude and 177.2 east longitude, in the northeastern Atalanta Region of Venus. It is in diameter. The crater is complex, characterized by a partial central ring and a floor flooded by radar-dark and radar-bright materials. Hummocky, rough-textured ejecta extend all around the crater, except to the west.
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The Caloris impact occurred during the time of formation of the intermediate plains material. In the map area, Caloris ejecta may be present at depth or may have been reworked locally by adjacent impacts. Two groups of Caloris secondary craters are evident. Shortly after the Caloris impact, extensive smooth plains material, probably of volcanic origin, was deposited.
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To the northwest is Bečvář. This is an eroded crater formation with several smaller craters along the rim. A chain of three small craters lies across the western rim and inner wall, and a crater cuts across the eastern rim. The inner walls have been worn and their features softened by impacts and possibly ejecta from other craters.
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Magellan mission to Venus in 1994, controversies about the origin of Cleopatra patera existed due to the asymmetric shape of the floor of the crater, which appeared smooth. This image is modified from David Kring, NASA University of Arizona Space Imagery Center, 2006. Most large impact craters do not have a central peak, yet have sharp rims bordered by asymmetrical radar bright ejecta blankets, have multiple rims, are surrounded and partially filled by subsequent lava which creates a reduced apparent depth, have dark crater floors, and buries some ejecta. By analyzing Magellan images, Cleopatra patera's was found to be distorted in shape in that its noncircular inner ring is off center, but also that the outflow channel of lava moves from within the crater and reaches the top of the crater rim.
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The location also provided a relatively smooth Mare surface and a proximity to the lunar equator, thus ensuring relative ease of access from the standpoint of fuel consumption. Geologically, the astronauts noted the amount of glass contained in the regolith and present at the bottoms of shallow craters at the site, as well as lighter-colored regolith material that geologists later determined to be ejecta from Copernicus crater. The Copernicus ejecta sampled suggested that the Copernicus impact occurred about 800 million years ago, but geologists believe the results of this analysis are inconclusive. The Apollo 12 astronauts also noted the existence of small, shallow elongated depressions ("trenches" or "grooves") similar to those the Apollo 11 astronauts observed at Tranquility Base in the Sea of Tranquility; Shoemaker et al.
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From their trace element contents and stable isotopic compositions it is inferred that the mud water is a mixture of sediment pore water (ancient seawater) and water released from dehydration of clay minerals. The 87Sr/86Sr of mud water (~0.7071) confirms the above inference and points out that altered oceanic crust plays a significant role in controlling the chemistry of water. The formation temperatures of mud ejecta, derived from mineralogical (smectite/illite), chemical (K+/Na+) and isotopic (δD/δ18O) geothermometers, lie in the range of 50 °C to 120 °C — which corresponds to a depth zone of 2 to 6 km within the Andaman forearc. It is believed that the mud volcano ejecta originate at the plate-boundary décollement zone, from the sediments and altered oceanic crust of the subducting Indian plate.
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This weathering takes place as "the cold, magnetized relativistic wind launched by the star hits the non- relativistically expanding ejecta, a shock wave system forms in the impact: the outer one propagates in the ejecta, while a reverse shock propagates back towards the star." The former ejection of matter in the outer shock wave and the latter production of antimatter in the reverse shock wave are steps in a space weather cycle. Preliminary results from the presently operating Alpha Magnetic Spectrometer (AMS-02) on board the International Space Station show that positrons in the cosmic rays arrive with no directionality, and with energies that range from 10 GeV to 250 GeV. In September, 2014, new results with almost twice as much data were presented in a talk at CERN and published in Physical Review Letters.
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Trask and Guest concluded that the surface of these plains represents a primordial surface of Mercury on which craters have been superposed. The large extent of this surface compared to its counterpart on the Moon was thought to reflect the restricted distribution of ejecta around each individual crater caused by the relatively high gravity on Mercury. Because of this high gravity, considerable areas were unaffected by crater and basin ejecta. However, Malin and Guest and O’Donnell (1977) have shown that in some areas the intercrater plains overlie highly degraded craters, a relation suggesting either that the intercrater plains were formed during a specific time in Mercury’s history and that cratering occurred both before and after their emplacement, or, alternatively, that the intercrater plains were formed by a continuous process throughout cratering history.
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This pulverized rock can also produce "volcanic winter" effects, if sulfate-bearing rock is hit in the impact and lofted high into the air, and "nuclear winter" effects, with the heat of the heavier rock ejecta igniting regional and possibly even global forest firestorms. This global "impact firestorms" hypothesis, initially supported by Wolbach, H. Jay Melosh and Owen Toon, suggests that as a result of massive impact events, the small sand- grain-sized ejecta fragments created can meteorically re-enter the atmosphere forming a hot blanket of global debris high in the air, potentially turning the entire sky red-hot for minutes to hours, and with that, burning the complete global inventory of above-ground carbonaceous material, including rain forests.Reigniting the Cretaceous-Palaeogene Firestorm Debate Claire M. Belcher, Journal of Geology, . vol. 37, no.
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To the southeast is the somewhat larger Krieger. There are several small rilles to the southwest of Wollaston, forming part of the Rimae Prinz. This is a circular, cup-shaped crater with a higher albedo than the surrounding mare. It has a raised rim that is free from impact erosion, and is surrounded by a small radial skirt of ejecta.
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The landing site area is believed to be blanketed by ejecta excavated by the impact that created Heimdal, approximately 600 million years ago. The spacecraft was photographed during landing by the Mars Reconnaissance Orbiter, and was captured parachuting in the line of sight to the crater. While appearing to be over the crater, the craft was actually 20 km in front of it.
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Khensu crater is a crater on Jupiter's moon Ganymede. It is a dark-floored crater with a bright ejecta blanket located in the grooved terrain region Uruk Sulcus. The dark component may be residual material from the impactor that formed the crater. Another possibility is that the impactor may have punched through the bright surface to reveal a dark layer beneath.
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Alloriite is a relatively rare mineral that only appears in Italy. Originally it was found in Mt. Cavalluccio, Italy. It was recorded with its volcanic ejecta, which is the result of an explosive volcanic eruption. It was found on the south eastern slope, in the northern part of the caldera, the result of a large volcanic explosion, which in turn created a crater.
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Mayon Volcano in the Philippines has a symmetrical volcanic cone. Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fragments ejected during the eruption.
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The reserve is located south west of Alice Springs and contains over a dozen craters, which were formed when a fragmented meteorite hit the Earth’s surface. Henbury is one of five meteorite impact sites in Australia with remaining meteorite fragments and one of the world's best preserved examples of a small crater field.Haines P.W. (2005). Impact cratering and distal ejecta: the Australian record.
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Dactyl may have originated at the same time as Ida, from the disruption of the Koronis parent body. However, it may have formed more recently, perhaps as ejecta from a large impact on Ida. It is extremely unlikely that it was captured by Ida. Dactyl may have suffered a major impact around 100 million years ago, which reduced its size.
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The surrounding terrain shows a radial pattern of grooves and braids running from north to south. Only a ring of material protrudes upward from this bed of ejecta, displaying the location of the original rim. There is a small craterlet along the northeast inner wall. This crater lies within the Mendel- Rydberg Basin, a 630 km wide impact basin of Nectarian age.
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An arc of craterous depressions from the south rim of Alphonsus curves to the west, dividing Alpetragius from Arzachel crater. To the west-northwest is the crater-like outline of Alpetragius X, now flooded by the mare and overlain across the east by ejecta from Alpetragius. Alpetragius is similar in appearance to Behaim crater on the far side, although Behaim is larger.
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Oblique Lunar Orbiter 5 image Minnaert is a large lunar impact crater that is located on the far side of the Moon, deep in the southern hemisphere. It is partly overlain along the southeastern side by the larger and younger crater Antoniadi. To the west-northwest lies Lyman. Nearly half the crater is overlain by the rim, outer rampart, and ejecta from Antoniadi.
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Lofn is one of the youngest impact craters on Callisto. All its geological units contain much less small impact craters than the surrounding crater plains. The age of Lofn is estimated at 1.39-3.88 billion years depending on the assumed cratering rate in the past. The significant asymmetry in distribution of the impact ejecta indicates that Lofn was formed by an oblique impact.
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Smooth plains are most strikingly exposed in a broad annulus around the Caloris basin. No unequivocal volcanic features, such as flow lobes, leveed channels, domes, or cones are visible. Crater densities indicate that the smooth plains are significantly younger than ejecta from the Caloris basin. In addition, distinct color units, some of lobate shape, are observed in newly processed color data.
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Suffering from burnt wings, the male pterosaur falls from the sky to his death. After trying to save her mate, the also wounded female is forced to land in the valley. The effects of the ejecta also caused lightning storms to strike the valley. The soaring temperatures create high humidity in the valley and force the Triceratops to keep moving.
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The outer rampart of ejecta spills over slightly into the Apollo basin floor, but the remainder of the rim lies in rugged irregular ground. At the midpoint is a central peak formation with a pair of tiny craters to either side: east and southwest. The remaining floor is relatively flat to the north and somewhat more irregular to the south.
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The name fiamme comes from the Italian word for flames, describing their shape. The term is descriptive and non- genetic. Fiamme are most typical of welded lapilli-tuffs and are commonly found in association with eutaxitic textures, best seen under the microscope. Some fiamme represent fragments of volcanic ejecta, often pumice lapilli that have been flattened by compaction and/or shear.
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They are a regolith breccia consisting mostly of eucrite and diogenite fragments, although carbonaceous chondrules and impact melt can also occur. The rock formed from impact ejecta which was later buried by newer impacts and lithified due to the pressure from overlying layers. Regolith breccias are not found on Earth due to a lack of regolith on bodies which have an atmosphere.
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These unusual streaks, seen only on Venus, are believed to result from the interaction of crater materials (the meteoroid, ejecta, or both) and high-speed winds in the upper atmosphere. The precise mechanism that produces the streaks is poorly understood, but it is clear that the dense atmosphere of Venus plays an important role in the distribution of the ejected material.
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Fuel is mined from Phobos with the help of a nuclear reactor. (P. Rawlings, 1986) In 1997 and 1998, the Aladdin mission was selected as a finalist in the NASA Discovery Program. The plan was to visit both Phobos and Deimos, and launch projectiles at the satellites. The probe would collect the ejecta as it performed a slow flyby (~1 km/s).
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The ray material extends for over and has not been significantly darkened by space erosion. Some of the ejecta appear to extend as far as the crater Boss, over to the northwest. The outer rim of the crater is especially bright compared to its surroundings. To all appearances, this is a young formation that was created in the relatively recent past, geologically speaking.
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Moreover, Berkel is surrounded by a blanket of bright ejecta and a system of bright rays. Other craters on Mercury’s surface, such as Bashō, also exhibit both bright rays and dark halos. In contrast, two neighboring craters have bright rays but lack dark halos. Berkel lies within the much larger and older crater Ellington, which is to the southeast of Derain.
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It is viewed nearly edge-on, making observation of the interior difficult from the Earth. The rim of Olbers is somewhat worn, with notches to the north, east, and south. The interior floor is relatively flat, especially toward the eastern rim, and is not marked by notable craterlets. The floor is covered by ray material and ejecta from the adjacent Glushko.
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Elvey is a lunar impact crater that is located on the far side of the Moon. It is located near the northern edge of the blanket of ejecta that surrounds the Mare Orientale impact basin. To the north of Elvey is the smaller crater Nobel. This is a damaged crater with a rim that is only partly intact along the eastern side.
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The smooth plains unit probably includes materials of a wide range in age, but the exposed areas are too small to test this possibility quantitatively. Although a volcanic origin cannot be ruled out for all or part of the smooth plains material, it is more probably a mixture of ejecta from very small craters and colluvium mass wasted from crater walls.
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The surface of Alphonsus is broken and irregular along its boundary with Ptolemaeus. The outer walls are slightly distorted and possess a somewhat hexagonal form. A low ridge system of deposited ejecta bisects the crater floor, and includes the steep central peak designated Alphonsus Alpha (α). This pyramid-shaped formation rises to a height of 1.5 km above the interior surface.
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The Dostoevskij impact probably occurred in cl time. The Tolstoj Basin is centered in the Tolstoj quadrangle at –16°, 165° (Schaber and McCauley, 1980). It consists of three discontinuous rings; ejecta may be mapped as far as 350 km from the outermost ring. The density of superposed craters suggests an age older than the Caloris Basin, either late c1 or early c2.
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Oblique view facing east with a high sun angle, from Apollo 8, showing the dark-halo crater within. High resolution view of the unnamed dark-halo crater. The halo of dark ejecta itself is visible but not prominent in this photo due to a low sun angle. Lunar Orbiter 3 image Neujmin is a lunar impact crater on the Moon's far side.
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LRO image at a much lower sun angle than above Pierazzo is a small lunar impact crater on the far side of the Moon. It is located within the north- northwestern section of the immense skirt of ejecta that surrounds the Mare Orientale impact basin. To the south is the Montes Cordillera mountain ring. To the west is the crater Lents.
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The Rove Formation, is a sedimentary rock formation of Middle Precambrian age underlying the upper northeastern part of Cook County, Minnesota, United States, and extending into Ontario, Canada. It is the youngest of the many layers of sedimentary rocks which constitute the Animikie Group. Before the Rove sediments were laid down, during the Archean Eon, the Algoman orogeny added landmass along a border from South Dakota to the Lake Huron region; this boundary is the Great Lakes tectonic zone. Several million years later a thin layer of hypervelocity impact ejecta from the Sudbury impact event was deposited on the older, underlying, Gunflint Iron Formation, and the Rove was then deposited on top of the ejecta; it is estimated that at ground zero the earthquake generated by the meteor impact would have registered 10.2 on the Richter scale.
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One hypothesis for its origin is that shock waves generated during the Caloris impact traveled around Mercury, converging at the basin's antipode (180 degrees away). The resulting high stresses fractured the surface. Alternatively, it has been suggested that this terrain formed as a result of the convergence of ejecta at this basin's antipode. Overall, about 15 impact basins have been identified on the imaged part of Mercury.
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This video shows the particle flow around Earth as solar ejecta associated with a coronal mass ejection strike. A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the solar corona. They often follow solar flares and are normally present during a solar prominence eruption. The plasma is released into the solar wind, and can be observed in coronagraph imagery.
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The western peak is designated Psi (ψ), the eastern Phi (φ), and the northern peak is Alpha (α) Theophilus. The western slopes of this ridge are wider and more irregular, whereas the peaks descend more sharply to the floor on the northern and western faces. The Apollo 16 mission collected several pieces of basalt that are believed to be ejecta from the formation of Theophilus.
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This definition, however, has recently been subjected to some criticism as some crater rays are bright for compositional reasons that are unrelated to the amount of space weathering they have incurred. In particular, if the ejecta from a crater formed in the highlands (which is composed of bright anorthositic materials) is deposited on the low albedo mare, it will remain bright even after being space weathered.
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Abstract @1255. Mojave is a rayed crater, another indication of its youth, and is the largest such crater on Mars. Based on crater counts of its ejecta blanket, it is thought to be about 3 million years old. It is believed to be the most recent crater of its size on Mars, and has been identified as the probable source of the shergottite meteorites collected on Earth.
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Kleymenov is a crater on the far side of the Moon. It is located near the east-northeastern outer wall of the huge walled plain Apollo, and to the west- northwest of the large crater Chebyshev. To the north is Mariotte. This is an older, worn feature, particularly along the western edge where ejecta material covers the rim and part of the inner walls and floor.
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The 2005 Deep Impact collision with the comet Tempel 1.Chapter 10 – Comets Astronomy 9601 The impact flash and resulting ejecta are clearly visible. The impactor delivered 19 gigajoules (the equivalent of 4.8 tons of TNT) upon impact.NASA deep impact impactor Deep Impact: Excavating Comet Tempel 1 It generated a predicted velocity change in the comet's orbital motion and decreased its perihelion distance by .
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When adjoining walls between pits in a pit crater chain collapse, they become troughs. In these cases, the craters may merge into a linear alignment and are commonly found along extensional structures such as fractures, fissures and graben. Pit craters usually lack an elevated rim as well as the ejecta deposits and lava flows that are associated with impact craters.Okubo, Chris, and Stephen Martel.
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Geologically, the falls are located on a cliff created by a volcanic ejecta some 15 million years ago. During winter the falls may freeze. The closest train station is Fukuroda Station on the JR East Suigun Line located 3 kilometers away. By car, the falls can be reached from the Naka Interchange on the Jōban Expressway to Japan National Route 118 in the direction of Ōmiya.
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The surface has one artificial crater, which was intentionally formed by the Small Carry-on Impactor (SCI), which was deployed by Hayabusa 2. SCI fired a 2 kg copper mass onto the surface of Ryugu on 2019-04-05. The artificial crater showed a darker sub-surface material. It created an ejecta of 1 cm thickness and excavated material from up to 1 meter depth.
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However, until the impact's age is determined, the connection between the Hiawatha impact and the younger Dryas event remains a suggestion. However, if correct, its associated ejecta would have dispersed as far as Pilauco Bajo in southern Chile. Dating the Hiawatha crater requires drilling almost through the ice sheet above the crater to obtain a sample of dateable, solidified impact melt from the crater.
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This research contributed significantly to the understanding of this impact crater. Ocampo has subsequently led at least seven research expeditions to the Chicxulub site. Ocampo also led the expedition to Belize ejecta site, another crater impact site linked to the Caribbean and Mexico. She continues to search for new impact craters, and with her team, in 2017, reported on a possible crater near Cali, Colombia.
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It reached maximum light on May 21, then steadily declined in magnitude thereafter. Observations of the ejecta a year later showed that the explosion created 0.4 times the mass of the Sun worth of iron. The spectrum of the supernova remnant confirmed the presence of radioactive 56Co, which decays into 56Fe. Messier 96 is about the same mass and size as the Milky Way.
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To the south is the huge walled plain Hertzsprung. This is a worn crater with a low, outer rim. The southeast rim and the eastern interior floor are marked by ejecta deposits that trend from southeast to northwest. There is also a nearly linear series of small craters that begin to the southeast of the crater, and continue about 100 km to the northwest of the crater.
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Pictet is a lunar impact crater located just to the east of the larger and more prominent impact crater Tycho. The high-albedo rays and ejecta from Tycho lie across Pictet and spread far to the east and in other directions. Pictet is older than Tycho and is somewhat worn by past impacts. The slightly smaller crater Pictet A intrudes slightly into the southwest rim.
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The ejecta on the exterior forms an irregular outer rampart that extends for up to 100 kilometers. The Schrödinger impact basin is one of a few locations on the Moon that show evidence of geologically recent volcanic activity. A geological study of the basin shows evidence of lava flows and eruptions from vents. There is also older volcanic material and material scattered because of impacts.
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Suisei Planitia is a large basin on Mercury. Ghost craters are unusual forms that occur in the Suisei Planitia. They are buried and rounded in profile, with only their rim crests rising above the surrounding smooth plains. It has been suggested that the smooth plains that Suisei Planitia is part of (Caloris Planitia) might be ejecta from Caloris that were melted by the impact.
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Adrastea is the largest contributor to material in Jupiter's rings. This appears to consist primarily of material that is ejected from the surfaces of Jupiter's four small inner satellites by meteorite impacts. It is easy for the impact ejecta to be lost from these satellites into space. This is due to the satellites' low density and their surfaces lying close to the edge of their Roche spheres.
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The dark ejecta and floors plains of these craters are distinctly redder than the surrounding plains, whereas their anomalously bright floor patches, central peaks, and wall areas are distinctly bluer. None of these dark- halo craters has associated bright rays, although secondary craters are well preserved. Compositional implications of contrasting color differences for mercurian crater and plains materials have been discussed by Hapke and others.
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On Sarigan, the species has been recorded most frequently in high-elevation native forests on the trunks of large Erythrina variegata specimens, often resting at the base of branches. On 19 May 2015 specimens were found consuming the Pandanus-fruit ejecta of the Mariana Fruit Bat on the leaves of a Pandanus tectorius tree. Mariana partulids have been noted to consume plant material, both living and decaying.
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Jeanne is an impact crater on Venus. The distinctive triangular shape of the ejecta indicates that the impacting body probably hit obliquely, traveling from southwest to northeast. The crater is surrounded by dark material of two types. The dark area on the southwest side of the crater is covered by smooth (radar-dark) lava flows which have a strongly digitate contact with surrounding brighter flows.
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The very dark area on the northeast side of the crater is probably covered by smooth material such as fine-grained sediment. This dark halo is asymmetric, mimicking the asymmetric shape of the ejecta blanket. The dark halo may have been caused by an atmospheric shock or pressure wave produced by the incoming body. Jeanne crater also displays several outflow lobes on the northwest side.
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One rock, “Bounce Rock,” found sitting on the sandy plains was found to be ejecta from an impact crater. Its chemistry was different than the bedrocks. Containing mostly pyroxene and plagioclase and no olivine, it closely resembled a part, Lithology B, of the shergottite meteorite EETA 79001, a meteorite known to have come from Mars. Bounce rock received its name by being near an airbag bounce mark.
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Tektites (from Greek tektos, molten) are not themselves meteorites, but are rather natural glass objects up to a few centimeters in size that were formed—according to most scientists—by the impacts of large meteorites on Earth's surface. A few researchers have favored tektites originating from the Moon as volcanic ejecta, but this theory has lost much of its support over the last few decades.
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They are best developed along the inner edge of the basin where steep inward-facing scarps are common, grading outward into smaller massifs and blocks. The range marks the crest of most prominent ring structure around Caloris. The type area is the region near 18°, 184.5° (FDS 229). It is thought to be composed of uplifted prebasin bedrock covered by deep-seated late ejecta from Caloris.
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The inner wall is slightly wider along the eastern side, perhaps from deposits of ejecta from nearby impacts. The interior floor of Sommerfeld is a nearly level plain that has most likely smoothed out through deposits of materials. There are some small craters on the eastern edge of the interior. There is no central peak complex, and only a small hill lies at the midpoint.
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"Lunokhod 1: 1st Successful Lunar Rover", Space.com. Retrieved May 31, 2018. In February 2020, Chinese astronomers reported, for the first time, a high-resolution image of a lunar ejecta sequence, and, as well, direct analysis of its internal architecture. These were based on observations made by the Lunar Penetrating Radar (LPR) on board the Yutu-2 rover while studying the far side of the Moon.
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One rock, "Bounce Rock", found sitting on the sandy plains was found to be ejecta from an impact crater. Its chemistry was different than the bedrocks. Containing mostly pyroxene and plagioclase and no olivine, it closely resembled a part, Lithology B, of the shergottite meteorite EETA 79001, a meteorite known to have come from Mars. Bounce rock received its name by being near an airbag bounce mark.
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This animation illustrates the generation of the debris and ejecta clouds after a spherical aluminum projectile impacts a thin aluminum plate at approximately 7 km/s. The frame interval is about 1 microsecond. A microsecond is an SI unit of time equal to one millionth (0.000001 or 10−6 or ) of a second. Its symbol is μs, sometimes simplified to us when Unicode is not available.
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Little of the outer rim of this crater remains intact, and what survives is worn and eroded. The outer rim now forms an irregular ring of peaks, broken in several locations by small craters. The most intact portion of the rim is a small arc along the eastern side. Likewise much of the interior floor is irregular due to overlying impacts or their ejecta.
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Oblique view of Schiaparelli from Apollo 15 just after sunrise, facing south. Oblique view of Schiaparelli under a low sun angle later in the Apollo 15 mission. It is clear in this view that the mare material has covered the ejecta of the crater. Schiaparelli is a lunar impact crater located on the western part of the Oceanus Procellarum, to the west of the crater Herodotus.
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The interior wall displays some slumping, and the floor is uneven with a few small rises from slump blocks. The crater has a notable ray system that extends for a distance of over 600 kilometers. The rays display an asymmetry of form, with the most prominent being rays to the northwest, north-northeast, and northeast. There is an arc with no ejecta to the southwest.
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One rock, "Bounce Rock," found sitting on the sandy plains was found to be ejecta from an impact crater. Its chemistry was different from the bedrocks. Containing mostly pyroxene and plagioclase and no olivine, it closely resembled a part, Lithology B, of the shergottite meteorite EETA 79001, a meteorite known to have come from Mars. Bounce rock received its name by being near an airbag bounce mark.
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To the northeast of the range here is the crater pair of Schlüter and Hartwig. The latter crater has been significantly modified by ejecta from Mare Orientale, while the former is a younger feature formed after this supposed impact. The southeastern portion of the range contains the craters Krasnov and Shaler. To the southeast of the latter formation is a radial valley formation named the Vallis Bouvard.
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In some parts along the rim, inward-facing scarps may be seen. The rim is not circular but appears to be petal-shaped. Outside the rim, a continuous ejecta blanket may be discerned. The morphology of impact features such as Neith results either from the response of a relatively weak target material to a high-energy impact or from long-term viscous relaxation of the surface subsequent to impact.
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Additional surfaces were covered by ash cloud surges, reaching thicknesses of no more than on the sides of the pyroclastic flows. In some parts of the edifice, ejecta formed layers thick enough to undergo landsliding. The deposits and small structures, such as levees and lobes, were conserved by the dry climate in the region. The ash from the volcano was carried by western wind towards Argentina and the Atlantic Ocean.
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Lunar Orbiter 5 image Houzeau is a lunar impact crater on the far side of the Moon. It is located to the northwest of the Mare Orientale impact basin, and ejecta from that event has fallen across this crater rim and its interior. To the south of Houzeau lies the crater Gerasimovich, and one crater diameter to the west is Belopol'skiy. To the northwest lies Fridman, with Ioffe to its southwest.
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In 2003 Hoffman was appointed a National Science Foundation Astronomy and Astrophysics Postdoctoral Fellow at University of California, Berkeley. Here she compiled the Women in Astronomy Resource Page. She became more involved in activities to promote diversity in physics and astronomy, working with Meg Urry on the American Astronomical Society Committee on the Status of Women in Astronomy. She worked with the Lawrence Berkeley National Laboratory on modelling supernova ejecta.
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Pluto's smaller moons, including Nix, were thought to have formed from debris ejected from a massive collision between Pluto and another Kuiper belt object, similarly to how the Moon is believed to have formed from debris ejected by a large collision of Earth. The ejecta from the collision would then coalesce into the moons of Pluto. However, the collisional hypothesis cannot explain how Nix maintained its highly reflective surface.
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The purpose of this experiment was to obtain information on the characteristics of the lunar surface. These characteristics included the amount of cratering, structure and size of craters, the amount, distribution, and sizes of ejecta, mechanical properties of the surface such as bearing strength, cohesiveness, compaction, etc. Determination and recognition of processes operating to produce the lunar surface features also were among the objectives of this photographic experiment.
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A reddish, asymmetric ejecta pattern Several models were devised to compute the density and size of Shoemaker–Levy 9. Its average density was calculated to be about ; the breakup of a much less dense comet would not have resembled the observed string of objects. The size of the parent comet was calculated to be about in diameter. These predictions were among the few that were actually confirmed by subsequent observation.
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One of the many nebular components (or anomalies) of the Crab Nebula is a helium-rich torus which is visible as an east–west band crossing the pulsar region. The torus composes about 25% of the visible ejecta. However, it is suggested by calculation that about 95% of the torus is helium. As yet, there has been no plausible explanation put forth for the structure of the torus.
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Thereafter, during the third phase, the outpouring of lava and ejecta deposits increased from Tarso Yega, Tarso Toon, Tarso Tieroko and Ehi Yéy; the collapse of these structures formed the first calderas. This phase also saw the formation of the Bounaï lava dome and Tarso Voon. To the east, the lava flows formed the large plateaus of Tarso Emi Chi, Tarso Ahon and Tarso Toon. Emi Koussi increased in height.
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Large impacts would have profoundly affected the climate by releasing huge quantities of hot ejecta that heated the atmosphere and surface to high temperatures. High impact rates probably played a role in removing much of Mars’ early atmosphere through impact erosion. Branched valley network of Warrego Valles (Thaumasia quadrangle), as seen by Viking Orbiter. Valley networks like this provide some of the strongest evidence that surface runoff occurred on early Mars.
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Ursula has a central pit with diameter of about 20 km. It is probably one of the youngest large impact craters on Titania. The crater is surrounded by smooth plains, which have the lowest impact crater density of all geological units on the moon, although they are cut by Belmont Chasma. The plains may be impact deposits (ejecta) associated with Ursula or they may be cryovolcanic in origin.
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The rim has been eroded to the point where it is not sharply defined, and both the edge and inner wall are rounded and relatively featureless. There is a small crater along the eastern rim. The interior floor is relatively featureless, except for the ejecta on the western edge. The west rim of the crater rises to a peak whose summit is over 6 km above the crater floor.
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Fumarole activity near Jigokunuma. The Hakkōda Mountains are two clusters of stratovolcanoes in the Northeastern Japan Arc that consists of lava flows, debris flows, and pyroclastic ejecta and flows arranged into southern and northern groups. The volcanic peaks are made of non-alkali mafic rock; mostly andesite, dacite, and basalt. Although both groups of mountains formed in the Pleistocene, the southern group is older than the northern group.
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Presolar grains ("stardust") from the Murchison meteorite provide information on the first minerals. In the early Universe, there were no minerals because the only elements available were hydrogen, helium and trace amounts of lithium. Mineral formation became possible after heavier elements, including carbon, oxygen, silicon and nitrogen, were synthesized in stars. In the expanding atmospheres of red giants and the ejecta from supernovae, microscopic minerals formed at temperatures above .
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The remainder of the rim is not in much better condition. It is worn and eroded, with multiple small craterlets along the edge and inner wall. Most of the rim structure has been worn away by subsequent impacts and deposits of ejecta, and now forms a rounded dip into the curving interior. A small chain of craters cuts across the rim and inner wall to the west-northwest.
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The relative age of any surface feature can be determined from the density of impact crater on it. The density of craters on the floor of Raditladi is about 10% of that on the plains west of Caloris. The crater density is same on the ejecta covered plains outside the basin. The smooths plains and hummocky plains also have the same crater density and therefore the same apparent age.
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One rock, "Bounce Rock", found sitting on the sandy plains was found to be ejecta from an impact crater, known as tektites. Its chemistry was different from the bedrock's. Containing mostly pyroxene and plagioclase and no olivine, it closely resembled a part, Lithology B, of the shergottite meteorite EETA 79001, a meteorite known to have come from Mars. Bounce rock received its name by being near an airbag bounce mark.
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The interior floor of Vlacq has been resurfaced by lava, leaving a nearly level base. The southwest half of the floor, however, is overlaid by ejecta from nearby impacts. In the midpoint of the floor is a rounded massif that is about 15 kilometers in length, being long along the northwest direction. The floor contains a number of tiny craterlets as well as several ghostly crater remnants in the western half.
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The satellite crater Biela B is attached to the southwestern outer rim, and ejecta from Biela covers the northwestern part of the interior. Despite a certain degree of wear, the rim of Biela remains relatively well-defined, especially in the southeast. The interior floor is flat and not marked by any craterlets of note. There is a central peak formation of three ridges located just to the northeast of the midpoint.
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Grachev is a lunar impact crater on the far side of the Moon. It lies to the northwest of the Mare Orientale impact basin, in the outer skirt of ejecta surrounding the Montes Cordillera mountain ring. Passing along the southwestern edge of Grachev is the Catena Michelson, a valley-like formation composed of a linear chain of small craters. This feature is radial to the Mare Orientale basin.
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Another Oblique view from Apollo 16 The relatively isolated location of this crater serves to highlight its well-formed shape. Bullialdus has a high outer rim that is circular but observers have noted a slightly polygonal appearance. The inner walls are terraced and contain many signs of landslips. The outer ramparts are covered in a wide ejecta blanket that highlights a radial pattern of low ridges and valleys.
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The perimeter of this crater is generally circular, with a few slight outward notches particularly to the southeast. It displays very little appearance of wear, and neither the interior nor the outer rampart are marked by any craters of note. The inner wall has slumped somewhat, and has formed a few terrace-like structures. The interior ejecta spreads a good way across the inner floor, covering nearly half the diameter.
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Another significant crater is Afon, which marks Ida's prime meridian. The craters are simple in structure: bowl-shaped with no flat bottoms and no central peaks. They are distributed evenly around Ida, except for a protrusion north of crater Choukoutien which is smoother and less cratered. The ejecta excavated by impacts is deposited differently on Ida than on planets because of its rapid rotation, low gravity and irregular shape.
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The outer glacis of Ganswindt covers nearly half the interior floor of Idel'son, reaching to the midpoint. The remainder of the interior and rim of the crater has been partly overlain by ejecta, producing a rounded, lumpy surface. Still the surviving outer rim remains distinct, and is not overlain by any other impacts of note. The largest impact within the interior is a tiny crater next to the southeastern inner wall.
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Fényi is a small lunar crater on the far side of the Moon. It lies near the southern edge of the huge, braided skirt of ejecta that surrounds the Orientale impact Basin to the north. Less than two crater diameters to the southwest is the much larger crater Mendel. Much of the rim and nearly all of this crater have been buried under material from the Orientale Basin impact.
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Brashear is a lunar impact crater on the far side of the Moon, in the southern hemisphere in the vicinity of the south pole. The crater is named after the American astronomer John A. Brashear. It lies just to the south of the walled plain Antoniadi, within the larger crater's outer rampart of ejecta. To the northeast besides Antoniadi is the crater Numerov, and southeast lies the younger De Forest.
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A pair of small craters also cross the western rim. Parts of the inner wall of Mendel display worn, terrace-like features that have become rounded. The interior floor of Mendel displays deposits and depressions that may have been formed by ejecta from the Mare Orientale formation. This crater lies on the western margin of the Mendel-Rydberg Basin, a 630 km wide impact basin of Nectarian age.
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In vaporization cutting the focused beam heats the surface of the material to boiling point and generates a keyhole. The keyhole leads to a sudden increase in absorptivity quickly deepening the hole. As the hole deepens and the material boils, vapor generated erodes the molten walls blowing ejecta out and further enlarging the hole. Non melting material such as wood, carbon and thermoset plastics are usually cut by this method.
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Xiao Zhao crater is small in comparison with many other craters on Mercury. However, Xiao Zhao's long bright rays make it a readily visible feature. The fresh, bright rays, which were created by material ejected outward during the impact event that formed the crater, indicate that Xiao Zhao is a relatively young crater on Mercury's surface. Hollows are present within Xiao Zhao and on the ejecta blanket near the rim.
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The higher albedo ejecta is continuous out to a distance of nearly two crater diameters, then forms wispy rays particularly to the northwest. These rays may overlap a second system to the east-southeast. Due to its prominent rays, Das is mapped as part of the Copernican System.The geologic history of the Moon, 1987, Wilhelms, Don E.; with sections by McCauley, John F.; Trask, Newell J. USGS Professional Paper: 1348.
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The crater Verdi, in diameter, is the largest of the younger craters. Its extensive ejecta blanket and secondary crater field are superposed on plains materials and older craters. The east half of the mapped area (between long 0° and 100° W.) is characterized by smooth plains material (Murray and others, 1974). This unit covers vast expanses of Borealis Planitia, a depression about in diameter that has an irregular arcuate west boundary.
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Esclangona has a small moon, provisionally named , which measures 4 kilometers in diameter, and orbits 140 kilometers from its parent. This wide separation relative to the pair's size is rather unusual and it is believed that both Esclangona and its moon are ejecta from an asteroidal collision in the past that left the scene as a co- orbiting pair; a similar pairing is 3749 Balam and its moon.
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Oblique Lunar Orbiter 5 view of Gerasimovich, facing west Gerasimovich is a lunar impact crater on the far side of the Moon. It lies beyond the western limb, to the west-northwest of the immense Mare Orientale impact basin. The outer blanket of ejecta from this impact reaches nearly to the rim of Gerasimovich. Nearby craters of note include Houzeau to the north and the smaller Ellerman to the southeast.
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Ganymede may have experienced a period of heavy cratering 3.5 to 4 billion years ago similar to that of the Moon. If true, the vast majority of impacts happened in that epoch, whereas the cratering rate has been much smaller since. Craters both overlay and are crosscut by the groove systems, indicating that some of the grooves are quite ancient. Relatively young craters with rays of ejecta are also visible.
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The strata into which Bonneville formed is thought to be loose debris, although some of the ejecta may have originated from more competent rocks. No underlying bedrock was exposed in the crater or the numerous craterlets in Bonneville's walls. The crater is relatively pristine and in particular has not been affected by water based erosion. It is likely that Bonneville is a secondary crater, given its low depth to diameter ratio.
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Asymmetries in the crater structure and the ejecta blanket imply that the projectile impacted at low angle from the south-southeast. The age is not accurately constrained but must be young because it is so well preserved for its small size, and the meteorite fragments have not weathered away; some authors suggest an age of as young as 3000 years.Shoemaker E.M. & Shoemaker C.S. 1988. Impact structures of Australia (1987).
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Acraman crater is a deeply eroded impact crater in the Gawler Ranges of South Australia. Its location is marked by Lake Acraman, a circular ephemeral playa lake about in diameter. The discovery of the crater and independent discovery of its ejecta were first reported in the journal Science in 1986. The evidence for impact includes the presence of shatter cones and shocked quartz in shattered bedrock on islands within Lake Acraman.
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Graff is a small lunar impact crater that lies along the southwestern limb of the Moon. It is located to the west of the Vallis Bouvard depression in the southern part of the ejecta blanket that surrounds the Mare Orientale impact basin. To the south-southwest is the smaller crater Catalán. The outer rim of this crater is roughly circular, with a slight outward protrusion along the southern side.
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A value of 0 is given for non-explosive eruptions, defined as less than of tephra ejected; and 8 representing a mega-colossal explosive eruption that can eject (240 cubic miles) of tephra and have a cloud column height of over . The scale is logarithmic, with each interval on the scale representing a tenfold increase in observed ejecta criteria, with the exception of between VEI-0, VEI-1 and VEI-2.
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Pontypool has been made into live stage productions in the United States and the United Kingdom. Originally, the film Pontypool was to be a radio play for CBC Radio. Burgess wrote out a script for Pontypool in 48 hours, his approach inspired by Orson Welles' radio broadcast of War of the Worlds. He also played in the film adaption of Pontypool and in the science fiction film Ejecta.
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The other hypothesis says that the hills are lava flows, inflated during growth under some dense coating. All these versions have flaws. In particular, Ina does not seem to have a ring of volcanic ejecta, and the volcanic activity on the Moon seems to have ceased a long time ago. According to one another version, Ina appeared (and continues to form) due to collapse of the regolith into some underground cavities.
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Steklov is a lunar impact crater on the far side of the Moon, past the southwestern limb. It lies in the outer skirt of ejecta from the Mare Orientale impact basin, just to the southwest of the Montes Cordillera ring of mountains. About four crater diameters to the southwest is the slightly smaller crater Chant. The rim of this crater has a sharp edge that has not been eroded by impacts.
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This is a worn and eroded crater formation, with features that have become poorly defined and softened due to subsequent impacts and possibly some overlap of ejecta from Tsiolkovskiy and other sources. The inner rim is wider and has a gentler slope along the eastern side. The interior floor is relatively level, but contains some low rises. Only a few tiny craterlets dot the rim and interior of this formation.
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This crater lies in the midst of the skirt of ejecta that surrounds the Mare Orientale impact basin. Both the crater and its surroundings have been modified by this enormous amount of material, and the surface displays an uneven pattern that is generally radial to the basin, which is located to the north. The crater forms a shallow depression in the surface, with small craters along the southeastern and southwestern rim.
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The inner floor of Schwarzschild is relatively level by comparison with the rugged terrain outside, and is particularly flat in the north-northeastern half. There is a region of low, irregular ridges to the west of the midpoint. Lying in the southeastern part of the floor is the satellite crater Schwarzschild L, and surrounding this interior crater is an outer rampart formed from the ejecta material during its formation.
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There are no bright or dark crater rays, with the crater rim itself being higher in altitude than the surrounding cratered plains. The crater walls are degraded by slumping, forming distinct blocks of material. The crater floor consists of complex structures, including ejecta deposits, impact melts and possibly units placed by effusive volcanism. The bright bluish central peaks within the crater are arranged in a circular pattern forming a peak ring.
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The rim of Aristillus has a wide, irregular outer rampart of ejecta that is relatively easy to discern against the smooth surface of the surrounding mare. The crater impact created a ray system that extends for a distance of over 600 kilometers. Due to its rays, Aristillus is mapped as part of the Copernican System. The rim is generally circular in form, but possesses a slight hexagonal shape.
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Notably, they fill a wide ring surrounding the Caloris Basin. Unlike lunar maria, the smooth plains of Mercury have the same albedo as the older inter-crater plains. Despite a lack of unequivocally volcanic characteristics, the localisation and rounded, lobate shape of these plains strongly support volcanic origins. All the smooth plains of Mercury formed significantly later than the Caloris basin, as evidenced by appreciably smaller crater densities than on the Caloris ejecta blanket.
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There is a significant outward bulge along the rim edge to the south-southwest. A smaller crater lies across the rim to the west- northwest. The interior floor has low ridges and uneven areas most likely as the result of large deposits of ejecta. There is a cluster of small craters near the midpoint of the interior, and the worn remains of a pair of older impacts in the north and west.
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The age of the Orientale basin has not been directly determined, though it must be older than 3.72 Ga (based on Upper Imbrian ages of mare basalts) and could be as old as 3.84 Ga based on the size-frequency distributions of craters superposed on Orientale ejecta. About two-thirds of the Moon's mare basalts erupted within the Upper Imbrian Series, with many of these lavas filling the depressions associated with older impact basins.
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Nobel while at the lunar terminator Nobel is a crater that lies on the far side of the Moon. It is located in the northern edge of the vast skirt of ejecta surrounding the Mare Orientale impact basin. Less than three crater diameters to the south of Nobel is the larger crater Elvey, and to the west- southwest is the smaller Pease. This is a circular, bowl-shaped crater with a worn outer rim.
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It is generally thought that the presence of carbonates in rock is strong evidence for the presence of liquid water. Recent observations of the planetary nebula NGC 6302 show evidence for carbonates in space,Kemper, F., Molster, F.J., Jager, C. and Waters, L.B.F.M. (2001) The mineral composition and spatial distribution of the dust ejecta of NGC 6302. Astronomy & Astrophysics 394, 679–690. where aqueous alteration similar to that on Earth is unlikely.
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LRO Hawke is a lunar impact crater that is located on the southern hemisphere on the far side of the Moon. It lies within the larger Grotrian, located to the north of the huge walled plain Schrödinger, within the radius of that formation's outer blanket of ejecta. The crater's name was approved by the IAU on 16 March 2018. It is named after the American lunar scientist Bernard Ray Hawke (1946-2015).
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Noachian terrains consist of overlapping and interbedded ejecta blankets of many old craters. Mountainous rim materials and uplifted basement rock from large impact basins are also common. (See Anseris Mons, for example.) The number-density of large impact craters is very high, with about 400 craters greater than 8 km in diameter per million km2.Strom, R.G.; Croft, S.K.; Barlow, N.G. (1992) The Martian Impact Cratering Record in Mars, H.H. Kieffer et al.
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The lunar cratering record suggests that the rate of impacts in the Inner Solar System 4000 million years ago was 500 times higher than today.Carr, 2006, p. 23. During the Noachian, about one 100-km diameter crater formed on Mars every million years, with the rate of smaller impacts exponentially higher. Such high impact rates would have fractured the crust to depths of several kilometers and left thick ejecta deposits across the planet's surface.
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Stadius is a ghostly remnant of an ancient lunar impact crater that has been nearly obliterated by basaltic lava flows. It was named after Flemish astronomer Johannes Stadius. It lies to the southwest of the much younger crater Eratosthenes, at the north edge of Mare Insularum where the mare joins Sinus Aestuum. To the west is the prominent ray crater Copernicus, and multiple secondary craters from the Copernican ejecta cover this area.
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Hovnatanian is a crater on Mercury. Its “butterfly” pattern of ejecta rays were created by an impact at an even lower angle than that which formed neighboring Qi Baishi crater. From the "butterfly" pattern of rays (similar to Messier crater on the moon), the Hovnatanian impactor was travelling either north-to-south or south-to-north prior to hitting Mercury's surface. The crater was named for Hakob Hovnatanyan, a 19th century Armenian artist.
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The mass of the nebula cannot be determined directly. However, the amount of dust can be measured fairly accurately and estimates of the gas to dust ratio used to calculate the total mass. The total dust mass is calculated at , leading to estimates that up to of gas are contained in the Homunculus itself. Nearly as much material is detected within outer ejecta, which formed earlier, but within the last thousand years.
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Research by a team of international scientists in 2006 revealed that the Santorini event was much larger than the original estimate of of dense-rock equivalent (DRE) that was published in 1991. With an estimated DRE in excess of , the volume of ejecta was approximately . If so, the eruption's Volcanic Explosivity Index was 7. The volcano ejected up to four times as much as the well-recorded eruption by Krakatoa in 1883.
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The former partially embay the hummocky plains and are probably volcanic in origin. The latter are present mainly on a part of the floor between the peak ring and crater rim; they interpreted to be the original crater floor material not covered by the light colored lavas of smooth plains. The hummocky plains are slightly bluer than smooth plains. The areas outside Raditladi are covered by the dark relatively blue impact ejecta.
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The largest crater on Hyperion is approximately in diameter and deep. A possible explanation for the irregular shape is that Hyperion is a fragment of a larger body that was broken up by a large impact in the distant past. A proto- Hyperion could have been in diameter. Over about 1,000 years, ejecta from a presumed Hyperion breakup would have impacted Titan at low speeds, building up volatiles in the atmosphere of Titan.
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DN160822 03 is one of several quasi-satellites or temporary natural satellites of Earth. Two of them were destroyed as noted in the 9 February 1913 Great Meteor Procession. These could be the last remnants of a ring around the Earth composed of ejecta of a lunar volcano. The near-Earth asteroid 3753 Cruithne is a co-orbital object in a Horseshoe orbit, as are a number of other quasi- satellites of Earth.
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This is a worn crater formation with rim features that have been softened and rounded by subsequent deposits of ejecta. Attached to the eastern rim is the satellite crater Niepce F, and the inner wall of Niepce is wider along this edge. The remaining interior floor is relatively level, and offset toward the western side. There are several small impacts on the floor, the largest being a small craterlet along the north-northeastern edge.
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To the south-southwest of Lyapunov is the crater Hubble. The shape of this crater's rim has been modified due to the large adjacent formations, so that it is somewhat polygonal rather than circular. The rim along the western side is less affected by reshaping, although it too is worn by impact erosion. The ejecta from nearby impacts partly covers the northern and some of the southeastern parts of the interior floor.
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The visibility of this crater is also affected by libration of the Moon. As the eastern rim of Regnault lies across the rim of Volta, that eastern rim is somewhat less prominent than the western half. The rim has not been heavily eroded, although a small craterlet lies across the northern rim. Where it joins Stokes to the south, the rim has been straightened slightly, and ejecta lies across part of the interior floor.
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It is surrounded by an outer rampart of ejecta, most notably towards the north, and is at the center of a small ray system. Due to its rays, Harpalus is mapped as part of the Copernican System.The geologic history of the Moon, 1987, Wilhelms, Don E.; with sections by McCauley, John F.; Trask, Newell J. USGS Professional Paper: 1348. Plate 11: Copernican System (online) The inner surface is terraced, and flows down to the floor.
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Street is a lunar impact crater located just to the south of the prominent ray crater Tycho. Street lies within the skirt of high-albedo ejecta from Tycho, and it is more heavily worn than its younger and larger neighbor. There are several smaller craters joined to the western rim, as well as two craters along the eastern rim. The floor is relatively smooth and flat, except for a small craterlet in the western half.
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This is a relatively fresh crater formation that has not been degraded through impact erosion. The rim edge is well-defined except along the southwestern edge. Along that side skirt of ejecta from Karpinsky overlies the edge and the inner wall, reaching to the edge of the interior floor. The remainder of the inner wall has a slumped in places, forming a steep top section and shelves or terraces of slumped material.
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Beyond the crater rim there are two concentric outer rings made of bright and dark impact ejecta deposits. The central zone of Lofn (100-120 km in diameter) corresponds to the crater floor, which lies about 0.6 km below the surrounding cratered plains. Lofn is a shallow crater as compared to other craters of similar size. This is the main reason why it is called a flat-floored or anomalous dome crater.
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Near midnight on May 17, 1990, a meteorite fell into a field 20 km west of Sterlitamak and made a crater about 10 m in size and 5 m in depth with surrounding ejecta. Several fragments up to 6 kg were found in and near the crater. One year later the thumbprinted main mass of 315 kg was found when digging out the crater. The meteorite is made of iron of the octahedrite (IIIAB) type.
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The rim of this crater is circular and only marginally worn, with a pair of tiny impacts overlaying the southern edge. An outer rampart slopes down to the surrounding surface, and the interior wall slopes down more sharply to the crater floor. There is a terrace along the southeastern interior wall. Portions of the surroundings show evidence of ejecta deposits from Maunder to the north (as shown by a number of secondary impacts).
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They are Baetica (Bt), Achaia (AC), Etruria (Et), Narbonensis (Nb), Noricum (Nr), Pannonia (Pa), and Raetia (Ra). The Baetica region is situated around the north pole (in the center of the image) and includes a cluster of impact craters 21 km in diameter as well as their impact deposits. It is the youngest surface unit on Lutetia. Baetica is covered by a smooth ejecta blanket approximately 600 m thick that has partially buried older craters.
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As on the Moon, impact craters on Mercury are progressively degraded by subsequent impacts. The freshest craters have ray systems and a crisp morphology. With further degradation, the craters lose their crisp morphology and rays and features on the continuous ejecta become more blurred until only the raised rim near the crater remains recognizable. Because craters become progressively degraded with time, the degree of degradation gives a rough indication of the crater's relative age.
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Sulfur has been found encased in ejecta, which are often covered in volcanic glass from the interaction between seawater and lava. Volcanic rocks are porphyritic and contain many vesicles. The magma erupted at NW Rota-1 is among the most water rich of the entire Mariana Arc. The formation of NW Rota-1 magmas appears to involve the melting of subducted, water-bearing sediments and the interaction of the resulting melts with the mantle wedge.
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The very smooth plains unit, which is featureless and has no resolvable superposed craters, is possibly ejecta fallback on the floors of craters. However not all craters contain this material; some are floored by material with a rugged surface mapped as crater floor material, because it is analogous to the floor material in younger lunar craters such as Copernicus or Aristarchus. One other possibility is that the very smooth plains are volcanic.
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No terra material similar to that in the Kuiper quadrangle (De Hon and others, 1981) was recognized in the Beethoven quadrangle. Its absence may be due, in part, to fewer clusters of large young craters whose coalesced ejecta blankets could have yielded the coarsely textured, rough surfaces that characterize the unit in the Kuiper area. Also, the visible effect of roughness is diminished by the higher sun angle at which the Beethoven images were acquired.
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Mead is an impact crater on Venus named in honor of the cultural anthropologist Margaret Mead. Mead crater is the largest impact crater on Venus, with a diameter of 280 km (174miles). The crater has an inner and an outer ring and a small ejecta blanket surrounding the outer ring. Mead crater is relatively shallow (likely due to viscous relaxation and infilling) and crater floor looks very similar in morphology to the surrounding plain.
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Mars has a minimum distance from Earth of 54.6 million km that the ejecta would then have to travel with the perfect trajectory (dashed line) to impact on Earth. This is, in part, why Martian meteorites are rare on Earth. The meteorite is classified as a shergottite and is primarily basaltic in composition. EETA 79001 is the second largest Martian meteorite found on Earth, at approximately 7900 grams; only the Zagami meteorite is larger.
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Fissure in Flourmill lava flow The Flourmill Centre lies at the headwaters of Flourmill Creek and is the most southerly of the two Flourmill Volcanoes. It has an elevation of and rises above its base. Three overlapping cinder cones of slightly differing ages comprise the Flourmill Centre. The oldest cone lies on the northeastern side and is only partially preserved, with the southeastern side having been destroyed or buried by ejecta from subsequent eruptions.
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The crater is breached on the southwest side and contains the remnants of a lava lake. Late stage activity in the crater formed a small ring of extensively weathered scoriaceous ejecta on the northwest inner wall of the main crater. Like the Spanish Lake Centre to the north, lava from the Flourmill Centre flowed into the valley of Spanish Creek. Three lava flows have been identified, each having a thickness of along Spanish Creek.
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The crater floor is faintly marked by lighter-hued ejecta from the crater Giordano Bruno to the north. A linear formation of craters designated Catena Artamonov lies alongside the northeast rim of Artamov, following a course to the southeast. Nearby craters of note include Maxwell and Lomonosov to the northwest, and Edison to the west. To the east-northeast is the smaller crater Espin, while the small Malyy formation is located to the south-southeast.
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The structure is covered by a thin veneer of permanently frozen Pliocene and Pleistocene rock. This means that the age of the impact took place anywhere between 95 million and 3 million years ago. Palynological data on its ejecta suggest Middle–Late Turonian age of the impact (about 90 million years ago). The Avak structure provides the structural trap for the natural gas in the adjacent South Barrow and East Barrow gas fields.
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Harrison's observational research showed that the afterglows of gamma-ray bursts exhibit breaks in their decay rate due to collimation of the ejecta. Scientific highlights from the NuSTAR mission include mapping the radioactive debris in the Cassieopeia A supernova remnant to constrain the core collapse explosion mechanism, measurement of the spin of supermassive and stellar mass black holes, the discovery of a magnetar in the Galactic Center, and the discovery of an ultra luminous pulsar.
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These relations are similar to those associated with highly degraded, ancient basins on Mars (Chicarro and others, 1983). The smooth plains material displays numerous ridges that generally resemble lunar mare ridges and also are considered to be of tectonic origin. The mercurian ridges are probably related to minor compressive stresses that postdate smooth plains emplacement. Numerous lineaments are associated with basin rim material, but most of these lineaments are probably related to ejecta deposition.
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Bondarenko is a lunar impact crater on the far side of the Moon. It is located to the northeast of the large, dark-floored crater Tsiolkovskiy, and south of the crater Chauvenet. This is a worn crater formation with an irregular floor, similar to other craters in the area, which are covered by ejecta from Tsiolkovskiy. The crater was known as Patsaev G until 1991, when it was renamed by the IAU.
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In addition, they were more adaptable to airblast phenomena and produced a well defined blast wave without perturbation or ejecta; they also produced no crater. However, it was found that they lacked the high pressure associated with high explosives, and difficulties were encountered as the 20-ton gas balloon ruptured and another detonated unexpectedly during inflation. Ultimately ANFO was elected as a lower cost alternative to TNT for non-nuclear explosives tests.
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An SNR passes through the following stages as it expands: # Free expansion of the ejecta, until they sweep up their own weight in circumstellar or interstellar medium. This can last tens to a few hundred years depending on the density of the surrounding gas. # Sweeping up of a shell of shocked circumstellar and interstellar gas. This begins the Sedov-Taylor phase, which can be well modeled by a self- similar analytic solution (see blast wave).
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Poncelet is the remains of a lunar impact crater that is located near the northern limb of the Moon. It lies to the east-northeast of the crater Pascal and northwest of Anaximenes. Like the latter formation, Poncelet is a worn, eroded formation with an interior that has been flooded, either with lava or possibly ejecta. The outer rim is a low, circular ridge with a narrow break to the south and a wider breach to the northeast.
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The depth of a crater has been found to be about one tenth of its diameter. So by measuring the diameter, the depth can be easily found. They mapped the position and size of all of these craters and then determined the maximum size of single-layered craters and the smallest size for multiple- layered craters for each latitude. Remember the single-layered ejecta crater does not penetrate the icy layer, but the multiple-layered does.
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A major Plinian eruption occurred 26,450 ± 500 years ago, releasing of ejecta, both volcanic ash and pyroclastic flows. The deposits left contain both andesite and dacite, with phenocrysts consisting of apatite, augite, biotite, iron-titanium oxides, orthopyroxene and plagioclase in a rhyolite matrix. The Plinian deposit has a colour ranging from white to creamy. Like the Piedras Grandes rocks, they tend towards high potassium quantities, and resemble other volcanic rocks of Lascar and the Central Andes in composition.
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A fairly rare form of clastic rock may form during meteorite impact. This is composed primarily of ejecta; clasts of country rock, melted rock fragments, tektites (glass ejected from the impact crater) and exotic fragments, including fragments derived from the impactor itself. Identifying a clastic rock as an impact breccia requires recognising shatter cones, tektites, spherulites, and the morphology of an impact crater, as well as potentially recognizing particular chemical and trace element signatures, especially osmiridium.
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Oblique Lunar Orbiter 2 view, facing south Seidel is a worn lunar impact crater that lies to the east-northeast of the much larger crater Jules Verne. Farther to the east of Seidel is the western edge of Mare Ingenii, and to the northeast lies the crater O'Day. This is an eroded crater with a small crater overlying the south-southeastern outer rim. The southern rim is overlain by material deposits, most likely ejecta from another impact.
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Oblique Lunar Orbiter 5 image, facing west Pease is a lunar impact crater that lies in the north-northwestern edge of the huge skirt of ejecta that surrounds the Mare Orientale impact basin. It lies just over one crater diameter to the east of the smaller crater Butlerov. To the east-northeast of Pease is the somewhat larger Nobel. This is a roughly circular, bowl-shaped formation with an outer rim that is only moderately eroded.
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The meteorite vaporized and created a wide crater. Earthquakes shattered the ground hundreds of kilometers away and within seconds ejecta (cloud of ash, rock fragments, gases and droplets of molten rock) began to spread around the globe. It is estimated that at ground zero the earthquake would have registered 10.2 on the Richter magnitude scale. To put the Sudbury meteorite impact in perspective, the Chicxulub impact on the Yucatán Peninsula occurred with the impact of a diameter comet.
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It is not currently known whether it played a role in the fossae's formation or if its location is merely a coincidence, although no graben appears to cut the crater rim, and the dark impact ejecta partially covers grabens, suggesting that Apollodorus postdates Pantheon Fossae. In addition, the crater is slightly (by about 40 km) offset from the exact center of the Pantheon Fossae. Apollodorus of Damascus is credited as the architect of the Pantheon in Rome.
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Lagrange is a lunar impact crater that is attached to the northwestern rim of the crater Piazzi. It lies near the southwestern limb of the Moon, and the appearance is oblong due to foreshortening. To the northwest of this feature is the Montes Cordillera, a ring-shaped mountain range that surrounds the immense Mare Orientale impact basin. The southwestern half of this walled plain has been heavily damaged by the mass of ejecta from Mare Orientale.
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This minor planet was named by the discoverers after Australian geologist Victor Gostin (born 1940) of the University of Adelaide, who in the 1980s discovered the ejecta layer from the Acraman bolide impact at a distance of 300 kilometers from the impact site, within Ediacaran sedimentary rocks of the Flinders Ranges, South Australia, which enabled the impact to be dated at ~580 Ma. The official naming citation was published by the Minor Planet Center on 2 February 1988 ().
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Oblique Lunar Orbiter 5 image Kekulé is a lunar impact crater on the far side of the Moon. It lies just to the west-southwest of the larger crater Poynting, on the edge of the ejecta skirt surrounding the walled plain Hertzsprung to the southeast. The outer rim of Kekulé displays some degradation due to impact erosion, but is for the most part intact. The rim is roughly circular, with the greatest wear along the northeast rim.
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" The results from the Chandrayaan mission are also "offering a wide array of watery signals." On November 13, 2009, NASA announced that the LCROSS mission had discovered large quantities of water ice on the Moon around the LCROSS impact site at Cabeus. Robert Zubrin, president of the Mars Society, relativized the term 'large': "The 30 m crater ejected by the probe contained 10 million kilograms of regolith. Within this ejecta, an estimated 100 kg of water was detected.
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The crater was also imaged in great detail by Lunar Orbiter 5. From the 1950s through the 1990s, NASA aerodynamicist Dean Chapman and others advanced the lunar origin theory of tektites. Chapman used complex orbital computer models and extensive wind tunnel tests to support the theory that the so-called Australasian tektites originated from the Rosse ejecta ray of Tycho. Until the Rosse ray is sampled, a lunar origin for these tektites cannot be ruled out.
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Hartwig is a lunar impact crater that is located near the western limb of the Moon. It is attached to the eastern rim of the prominent crater Schlüter, to the northeast of the Montes Cordillera mountain range that surrounds the Mare Orientale. To the east-northeast of Hartwig is the larger crater Riccioli. This crater lies within the outer blanket of ejecta that surrounds the Mare Orientale impact basin, and its form has been modified by this material.
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However, recent analyses have shown that isolated particles of non- biogenic origin make up the majority of the magnetic particles in the thick clay unit. A 2016 report in Science describes the discovery of impact ejecta from three marine P-E boundary sections from the Atlantic margin of the eastern U.S., indicating that an extraterrestrial impact occurred during the carbon isotope excursion at the P-E boundary. The silicate glass spherules found were identified as microtektites and microkrystites.
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The Luna 2 landed in the gap between the craters Archimedes and Autolycus on September 14, 1959. The selenographic coordinates of Sinus Lunicus are 32.4° N and 1.9° W. Its diameter is 120 kilometers. The most distinctive features on the bay are the complex outer ramparts of ejecta from the craters Aristillus and Autolycus, and the small satellite craters Archimedes C and Archimedes D. The albedo of the surface is brightened by overlapping ray material from Autolycus and Aristillus.
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Inghirami is located near the southeastern edge of the immense skirt of ejecta that surrounds the Mare Orientale. This material has formed linear ridges and valleys that continue across most of the crater rim and interior from the northwestern face. Much of the outer rim has been modified by this impact material, and the most intact part of the rim lies along the southeast edge. The partly buried rim of this crater is roughly circular and somewhat irregular.
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Oblique Lunar Orbiter 5 image, facing west Chalonge is a lunar impact crater that is located on the far side of the Moon. It lies to the southwest of the larger crater Lewis, in the outer skirt of ejecta that surrounds the Mare Orientale impact basin. To the southeast are the Montes Cordillera, a ring of mountains that encircle the Mare Orientale formation. This is a circular crater with a sharp-edged, outer rim that is not appreciably eroded.
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It lies just to the south of the prominent crater Neper, and was designated Neper K before being given its current name by the IAU. To the west-southwest of Tacchini is the crater pair of Schubert and Back. This crater is roughly circular in form, with a rim that is better defined along the eastern side. The northwestern half of the floor is elevated, along the side where ejecta from the younger Neper intrudes into the interior.
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Mosaic of images recorded by Galileo 3.5 minutes before its closest approach Ida's surface appears heavily cratered and mostly gray, although minor color variations mark newly formed or uncovered areas. Besides craters, other features are evident, such as grooves, ridges, and protrusions. Ida is covered by a thick layer of regolith, loose debris that obscures the solid rock beneath. The largest, boulder-sized, debris fragments are called ejecta blocks, several of which have been observed on the surface.
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Because ejecta blocks are expected to break down quickly by impact events, those present on the surface must have been either formed recently or uncovered by an impact event. Most of them are located within the craters Lascaux and Mammoth, but they may not have been produced there. This area attracts debris due to Ida's irregular gravitational field. Some blocks may have been ejected from the young crater Azzurra on the opposite side of the asteroid.
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MER-B has had such new discoveries at the crater, that the rover team compared Endeavour to the equivalent of a second landing site for Opportunity. For example, On sol (August 22, 2011) the rover began examining Tisdale 2, a large ejecta block. "This is different from any rock ever seen on Mars," said Steve Squyres, principal investigator for Opportunity at Cornell University in Ithaca, New York. Opportunitys traverse up to March 2015 from its landing site to Endeavour.
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The crater ejecta is still visible in the rough surroundings beyond the rim, but any rays deposited during the impact have long since been worn away by space weathering. The inner wall is wide and extensively terraced, although these features are now somewhat muted due to impact erosion. There are no notable impacts on the interior floor, but there is a long, slender central ridge located at the midpoint and a pair of readily observed clefts.
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There are lower crater densities in areas of equatorial dunes and in the north polar region (where hydrocarbon lakes and seas are most common). Pre-Cassini models of impact trajectories and angles suggest that where the impactor strikes the water ice crust, a small amount of ejecta remains as liquid water within the crater. It may persist as liquid for centuries or longer, sufficient for "the synthesis of simple precursor molecules to the origin of life".
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A number of small craters lie along the rim and the inner wall. An impact along the northeast rim, just north of Von Zeipel, has a relatively high albedo and is surrounded by a skirt of bright material. This is indicative of a relatively recent impact that has not had time to darken due to space weathering. The eastern part of the interior floor is partly overlaid by the outer rampart and ejecta from Von Zeipel.
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A geological specialty of the park is the Rochechouart crater, the remnants of a meteorite impact at the end of the Upper Triassic (roughly 200 million years ago). The impact created a crater with a diameter of 21 kilometers and destroyed every form of life within a radius of several hundred kilometers. There is no trace of the original crater left, the only indicators for its existence are ejecta blankets (breccias and suevites), shatter cones and thrust faults.
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Other examples of such craters are Doh and Bran. The hummocky terrain (rim) surrounding the floor consists of randomly distributed massifs as large as 50 km and has mottled appearance at some places. The width of the rim unit varies from about 18 km on the north-west side to more than 130 km on the south-east side. The crater rim is encircled by a discontinuous ring of bright ejecta, which is asymmetric much like the rim itself.
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About one and a half crater diameters to the north is the large crater Clavius. This crater has undergone steady erosion from minor impacts, so that the features along the rim and inner wall have become softened and rounded. Significant impacts nearby have covered the floor and sides with ejecta, and there are a multitude of tiny craterlets along the inner wall. The satellite crater Gruemberger A lies within the interior, along the inner wall to the west- southwest.
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Very few of these secondary craters lie within 80 km of Zunil. Around 80% of the craters in Athabasca Valles are Zunil secondaries. If similar impacts also produced comparable amounts of secondaries, this calls into question the accuracy of crater counting as a dating technique for geologically young Martian surface features. A simulation of the Zunil impact ejected on the order of ten billion rock fragments greater than 10 centimeters in diameter, the total ejecta comprising 30 km3.
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Fresh craters of all sizes have dark or bright halos and well-developed ray systems. Although mercurian and lunar craters are superficially similar, they show subtle differences, especially in deposit extent. The continuous ejecta and fields of secondary craters on Mercury are far less extensive (by a factor of about 0.65) for a given rim diameter than those of comparable lunar craters. This difference results from the 2.5 times higher gravitational field on Mercury compared with the Moon.
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The data available on the crater indicate that Rembrandt is one of the youngest giant impact features on Mercury. Its age is roughly the same as that of Caloris. The basin probably formed near the end of the Late Heavy Bombardment of the inner Solar System about 3.9 billion year ago. The impact had excavated material from the lower part of the crust leading to the formation of the dark and relatively blue impact ejecta, which surrounds Rembrandt.
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Apollo 16 image Glauber is a small lunar impact crater that is located just to the north of the large walled plain Mendeleev, on the Moon's far side. This crater lies just outside the irregular rim of Mendeleev, but well within the outer skirt of ejecta. It is a circular crater with a rim that has not been significantly eroded. The simple inner walls slope down to a small floor at the midpoint with a peak at the center.
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Oblique Lunar Orbiter 5 image, facing west Ellerman is a lunar impact crater on the far side of the Moon. It lies within the outer blanket of ejecta that surrounds the Mare Orientale impact basin, and is located to the west of the Montes Cordillera mountain range. To the northwest of Ellerman is the larger crater Gerasimovich. Probably due to its location amidst rugged surroundings, the otherwise circular rim of this crater is somewhat irregular and polygonal in shape.
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Oblique Lunar Orbiter 5 image, facing west Lewis is a crater on the far side of the Moon. It lies along the western edge of the Montes Cordillera mountains that surround the Mare Orientale impact basin. This crater has been heavily disrupted by the formation of the basin, and it is covered by ejecta from the impact leaving only an uneven depression in the surface. The outer rim is roughly circular, and the interior is uneven.
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A hypermassive neutron star was believed to have formed initially, as evidenced by the large amount of ejecta (much of which would have been swallowed by an immediately forming black hole). The lack of evidence for emissions being powered by neutron star spin-down, which would occur for longer-surviving neutron stars, suggest it collapsed into a black hole within milliseconds. Later searches did find evidence of spin-down in the gravitational signal, suggesting a longer-lived neutron star.
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A view of Lucretius from Lunar Orbiter 5, facing west Lucretius is an impact crater on the far side of the Moon. It is located to the southeast of the huge walled plain Hertzsprung, within the outer skirt of ejecta that surrounds that impact feature. To the southwest of Lucretius lies Fridman. This crater is a relatively fresh impact, as the formation is well-defined and the rim and interior remain nearly unscathed from impact erosion.
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The rim edge is ill-defined in the western half where the inner wall is unusually wide. This edge may have become overlain by ejecta from other impacts to the west. Along the eastern face the crater has apparently merged with one or two other impacts, producing an outward double-bulge. There are several smaller impacts along the eastern rim, and a gouge in the surface forms a trough leading away to the northeast for nearly a crater diameter.
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Piazzi is an impact crater that is located near the southwestern limb of the Moon, and is attached to the southeastern rim of the walled plain Lagrange. About three crater diameters to the south is the crater Inghirami. Piazzi is seen at an oblique angle from the Earth, and it appears oblong due to foreshortening. As with Lagrange, this formation has been heavily modified by the ejecta from the formation of the Mare Orientale impact basin to the northwest.
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Leanne Macomber was a singer for the Texas electronic music band Neon Indian, and was also in duo called Fight Bite. Joel Ford was in an electronic music duo with Daniel Lopatin, named Ford & Lopatin. The two first met in 2009 when they were touring, and decide to start working on music together, thus forming Ejecta. Macomber wrote all the songs of Dominae, with Joel Ford handling production and co-writing on "It's Only Love" and "Jeremiah".
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Therefore, we can build up many local stratigraphic columns involving both crater or basin materials and nearby plains materials. Over all of Mercury, the crispness of crater rims and the morphology of their walls, central peaks, ejecta deposits, and secondary-crater fields have undergone systematic changes with time. The youngest craters or basins in a local stratigraphic sequence have the sharpest, crispest appearance. The oldest craters consist only of shallow depressions with slightly raised, rounded rims, some incomplete.
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Comparing these salt flats to ones observed on Earth, such as those in the Atacama Desert further supports the hypothesis of a formation due to evaporation. Using CRISM data, this study also observed phyllosilicates in the rims of craters and the surrounding ejecta to occur near the chlorides. Another study also observed phyllosilicates to be closely located to chlorides with CRISM, as well as THEMIS. Phyllosilicates also provide evidence for aqueous processes occurring during the Noachian period.
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The highest point of the volcano lies east-northeast of the caldera and reaches elevation. The caldera has an incomplete rim and is filled with snow, leaving a depression. The rim of the caldera is covered by volcanic ejecta including lapilli and lava bombs, probably the products of the most recent eruption of Mount Melbourne, which overlie a layer of pumice lapilli. Three small, nested craters formed by phreatomagmatic eruptions occur on the southern rim of the summit caldera.
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Chadwick is a lunar impact crater that lies on the far side of the Moon's surface, just beyond the southwestern limb. It is located to the northwest of the crater De Roy, and was previously designated De Roy X before being given its current name by the IAU. This region of the lunar surface lies at the southern end of the ejecta blanket that surrounds the Mare Orientale impact basin. Chadwick is roughly circular with a sharp-edged rim.
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Mount Rainier Hazard map Mount Rainier is a stratovolcano in the Cascade Volcanic Arc that consists of lava flows, debris flows, and pyroclastic ejecta and flows. Its early volcanic deposits are estimated at more than 840,000 years old and are part of the Lily Formation (about 2.9 million to 840,000 years ago). The early deposits formed a "proto-Rainier" or an ancestral cone prior to the present-day cone. The present cone is more than 500,000 years old.
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Diagram of WISPR The Wide-Field Imager for Solar Probe (WISPR) is an imaging instrument of the Parker Solar Probe mission to the Sun, launched in August 2018. Imaging targets include visible light images of the corona, solar wind, shocks, solar ejecta, etc. Development of WISPR was led by the U.S. Naval Research Laboratory. The Parker Solar Probe with WISPR on board was launched by a Delta IV Heavy on 12 August 2018 from Cape Canaveral, Florida.
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It can be located to the south- southeast of the prominent ray crater Copernicus. In the past, the floor of Gambart has been flooded with lava, leaving a relatively flat surface surrounded by a smooth but somewhat polygon-shaped outer rim. To the southwest of Gambart is an area of hilly terrain deposited from ejecta during the Mare Imbrium impact, known as the Fra Mauro Formation. The smaller Gambart C crater is located to the northeast of Gambart itself.
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Further to the south is Epigenes. The heavily eroded outer rim of Goldschmidt is rugged and irregular, with an inner wall that is incised in several locations by small impacts. Much of the western rim no longer exists, due to the overlapping Anaxagoras and the smaller Anaxagoras A, and the ejecta from these formations covers the western third of the interior floor. The remaining floor is nearly level and flat, most likely having been resurfaced by lava flows.
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Müller is a 120.5 kilometer crater in the Martian southern hemisphere, at 25.74°S, 127.89°E, located in the Terra Cimmeria region of the Mare Tyrrhenum quadrangle of Mars. According to the International Astronomical Union's Working Group for Planetary System Nomenclature, Müller is jointly named for Hermann Joseph Muller, an American geneticist and anti-nuclear weapons activist, and Carl H. Müller, a German astronomer. Ejecta from the Müller crater divides two Noachian era drainage basins. Muller Crater has a central peak.
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Parts of the interior floor of Darwin have been resurfaced. The southern floor of Darwin is only roughly level, with irregular surface features and several small craters. There is a dune-like set of hills in the northeast part of the floor, which is "decelerated surface-flow ejecta" from the Orientale basin impact that struck the eastern rim.The geologic history of the Moon, 1987, Wilhelms, Don E.; with sections by McCauley, John F.; Trask, Newell J. USGS Professional Paper: 1348.
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Heyrovsky is a small lunar impact crater on the far side of the Moon. This crater lies just beyond the southwestern limb, in an area of the surface that is sometimes brought into view of the Earth during periods of favorable libration and illumination by sunlight. It lies within the southern part of the wide skirt of ejecta that surrounds the Mare Imbrium impact basin. This is a circular crater formation with an interior that is shaped like a bowl.
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Oblique view from Apollo 10 Oblique view of small, unnamed crater with dune- like ejecta, near the northwest rim of Papaleksi, from Apollo 16 Papaleksi is an impact crater on the far side of the Moon. It lies along the northeastern outskirts of the large crater Mandel'shtam. About 20 km to the north-northeast of Papaleksi is the similar crater Spencer Jones. This is a roughly circular crater with an eroded outer rim that has lost much of its original sharp definition.
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Bingham is a small lunar impact crater that is located on the far side of the Moon, relative to the Earth. It is named after the American academic, explorer and politician Hiram Bingham III. It lies just to the southeast of the much larger crater Lobachevskiy, and the northwestern part of the rim of Bingham is partly overlaid by ejecta from Lobachevsky. To the northeast of Bingham is the crater Guyot, and about a crater diameter to the south-southeast is Katchalsky.
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Oblique view at low sun angle showing detail of the crater's interior Qi Baishi is a crater on Mercury. The crater was named after famed Chinese painter Qi Baishi. The crater has an asymmetric pattern of ejecta rays, which formed by an object traveling to the east or to the west and impacting Mercury's surface at a very low incidence angle. However, Qi Baishi crater is still roughly circular, which is in contrast to the elongated shape of neighboring Hovnatanian crater.
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This ejecta forms a nearly continuous blanket out to at least one crater diameter before forming extended rays and a multitude of wispy markings across the surface. The ray system continues for several hundred kilometers, including extending across a substantial portion of the Korolev basin. Due to these prominent rays, Crookes is mapped as part of the Copernican System. As would be expected for a relatively young crater, Crookes has a sharp-edged rim that has not been significantly eroded.
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Oblique view Mariner 10 image with Verdi crater near center Verdi is a relatively young impact crater on the planet Mercury. It was named after Italian Romantic composer Giuseppe Verdi (1813–1901) in 1979, as recognized by the International Astronomical Union. The crater's extensive ejecta blanket and secondary crater field are superposed on plains materials and older craters. Verdi lies in the northern section of the Shakespeare quadrangle and is relatively large for a Mercurian crater, with a low rim and shallow floor.
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Ejecta from the Sudbury Impact was found in May 2007 on the Gunflint Trail in Cook County, Minnesota. Geologists Mark Jirsa and Paul Weiblen from the University of Minnesota took advantage of the burnt-over landscape resulting from the intense, hot Ham Lake fire to explore the newly exposed geology along the Gunflint Trail. Jirsa picked up some rocks which turned out to be ash and debris from the distant impact site; this is the farthest distance that Sudbury detrita has been found.
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Lunar Orbiter 4 image Mees is a crater on the far side of the Moon. It is located in a part of the lunar surface that is sometimes brought into view of the Earth under conditions of favorable libration and illumination. Even at such a time, however, this feature is seen from a very low angle and little detail can be perceived. This crater lies in the northern edge of the huge skirt of ejecta that surrounds the Mare Orientale impact basin.
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It is considered the deepest crater on the near side of the Moon. The interior of Newton is a picture in contrasts. The southern end has been covered, possibly by lava flows or ejecta, leaving a relatively flat surface that is marked only by tiny craters and a slight wrinkle ridge down the middle. The northern half is rugged and irregular, with the satellite crater Newton D overlying the north- northeastern rim and extending across nearly half the crater diameter.
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It is believed that only shock metamorphism caused by a hypervelocity impact can transform plagioclase into maskelynite, or create planar deformation features. The presence of impact deformation of basalt layers comprising the rim, of shocked breccia inside the crater, of shatter cones, and of the non-volcanic ejecta blanket surrounding the crater all support the impact origin of Lonar Lake. The crater has an oval shape. The meteorite impact came from the east, at an angle of 35 to 40 degrees.
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The crater has a well-defined circular rim, terraced inner wall, central mountain peaks, an irregular floor, and an outer rampart of ejecta. It lacks a ray system of its own, but is overlain by rays from the prominent crater Copernicus to the south-west. The Eratosthenian period in the lunar geological timescale is named after this crater, though it does not define the start of this time period. The crater is believed to have been formed about 3.2 billion years ago.
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The crater Azzurra, for example, is named after a submerged cave on the island of Capri, also known as the Blue Grotto. Azzurra seems to be the most recent major impact on Ida. The ejecta from this collision is distributed discontinuously over Ida and is responsible for the large-scale color and albedo variations across its surface. An exception to the crater morphology is the fresh, asymmetric Fingal, which has a sharp boundary between the floor and wall on one side.
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These moonlets may be anywhere in size from gravel to stadium-sized. Their origins are unknown, but they may be gravitationally captured into current orbit or they may be ejecta from meteor impacts on Amalthea. On the next and final orbit (just an hour before destruction), Galileo detected one more such moonlet. However, this time Amalthea was on the other side of the planet, so it is probable that the particles form a ring around the planet near Amalthea's orbit.
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Fe II still dominates the spectrum. The Ca II infrared triplet is weak in SN 2002cx as compared to other type Ia supernovae, as expected since the Ca II H & K line is also weak in SN 2002cx. Unlike other type Ia supernova, SN 2002cx has double-peaked emission lines which may be due to jet- like emissions or rotating ejecta, or may simply only be seen in SN 2002cx because its low expansion velocity does not wash them out.
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Bárcena crater Barcena's only historic eruption began around 8:30 AM on August 1, 1952, from the El Boquerón vent. In a severe Vulcanian eruption of magnitude 3 on the Volcanic Explosivity Index scale, pyroclastic flows rolled over the island. Soon the entire island was covered in ash and pumice up to 3 m (10 ft ) high. Ejecta filled the valley between Herrera crater and Montículo Cinerítico, and by August 14 had formed a cone some 300 m (over 1000 ft) high.
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Location of the lunar crater Mitchell Mitchell is a lunar impact crater, which is attached to the eastern rim of the larger and more prominent crater Aristoteles. It was named after American astronomer Maria Mitchell. The floor of Mitchell is rough and irregular, with a low central rise, being partially filled with the ejecta of the younger Aristoteles. There is a slight notch in the southern rim, and the western wall has been completely absorbed by the rim of Aristoteles.
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There is a small, very eroded crater attached to the exterior to the southeast, and Numerov Z is nearly connected to the northern rim. The interior floor of Numerov is relatively level, but with a central peak formation at the midpoint and some low ridges just to the south. There are a few gouge-like grooves in the surface in the northeastern floor. The western half of the floor and inner walls have been partly overlain by ejecta from Antoniadi.
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Nearly all the rock east of the Sierra Nevada in the Mono Basin area is volcanic in origin. Volcanoes erupted from 3.6 to 2.3 million years ago near what is now Long Valley. Rhyolitic eruptions occurred in and around Glass Mountain in the same area from 2.1 to 0.8 million years ago. Volcanic ash from the massive ( of ejecta) eruption of Long Valley Caldera some 760,000 years ago is preserved in the thick Bishop Tuff that covers much of the region.
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TV camera still of Big Muley prior to collection. Big Muley was discovered on the eastern rim of Plum crater (Station 1) in the Descartes highlands of the Moon. The rock's cosmic ray exposure age was discovered to be about 1.8 million years, linking it to ejecta, or debris, from the impact that formed South Ray crater, to the south of the Apollo 16 landing site. The rock's age has been estimated since 1980 to be approximately 3.97 ± 0.25 billion years.
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Their origin may be genetically related to the inner rings of larger craters and basins. Crater floors are underlain by a zone of shattered and brecciated material formed by the shock wave resulting from impact. Crater-rim material consists of decompressed ejecta from the impact, whereas central peaks were probably formed by the converging flow of slump material from the crater walls (Shoemaker, 1981). If a crater was sufficiently large, the converging flow resulted in an inner ring rather than a central peak.
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Goethe was not listed as an impact basin by Wood and Head because they considered the Mariner 10 photography too poor to confirm basin structures. However, most workers, beginning with Murray and others, have identified it as a basin. Goethe is bounded on its north and east sides by a gently sloping wall and discontinuous, low, hummocky rim material that may consist of ejecta deposits. These materials are similar to those occurring around the Caloris Basin in the Tolstoj quadrangle.
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Harden is a small lunar impact crater that lies in the eastern part of the interior floor of the walled plain Mendeleev. It is located on the far side of the Moon, and cannot been seen from the Earth. The crater is a circular, bowl-shaped feature with a slightly higher albedo than the surrounding terrain, but lacks the skirt of bright ejecta that many young impacts possess. The edge and interior are not notably eroded, and no significant craters overlie this feature.
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In planetary geology, a pedestal crater is a crater with its ejecta sitting above the surrounding terrain and thereby forming a raised platform (like a pedestal). They form when an impact crater ejects material which forms an erosion-resistant layer, thus causing the immediate area to erode more slowly than the rest of the region. Some pedestals have been accurately measured to be hundreds of meters above the surrounding area. This means that hundreds of meters of material were eroded away.
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High-resolution images obtained by the Japanese satellite SELENE in 2008 were used to date the crater by counting the smaller craters within it and its ejecta deposits. This gave an age of million years, much too old for the hypothesis. This raises the question of what the monks saw. An alternative theory holds that the monks just happened to be in the right place at the right time to see an exploding meteor coming at them and aligned with the Moon.
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An example Mini-RF total radar backscatter image taken in the 12.6 cm band. It shows a fresh lunar impact crater with an ejecta blanket surrounding it. The Miniature Radio-Frequency instrument (Mini-RF) is a synthetic aperture radar (SAR) instrument on the Lunar Reconnaissance Orbiter (LRO), which is currently in orbit around the Moon. It has a resolution of 30 m/pixel and two wavelength bands, a primary band at 12.6 cm and a secondary band at 4.2 cm.
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VEI and ejecta volume correlation The Volcanic Explosivity Index (VEI) is a relative measure of the explosiveness of volcanic eruptions. It was devised by Chris Newhall of the United States Geological Survey and Stephen Self at the University of Hawaii in 1982. Volume of products, eruption cloud height, and qualitative observations (using terms ranging from "gentle" to "mega- colossal") are used to determine the explosivity value. The scale is open- ended with the largest volcanoes in history given magnitude 8.
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This proposed impact structure is listed as just a Class 3 Suspected in David Rajmon's Impact Database from the Impact Field Studies Group. Rajmon specifically noted that this proposed impact structure is highly speculative and based upon numerous unfounded interpretations, including the impact origin of the pseudotachylites and alleged ejecta deposits. It is not listed as a confirmed impact structure in the Planetary and Space Science Centre's Earth Impact Database, as only Class 0 confirmed impacts are listed on the site.
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All of the NAKP rocks are pyroclastic, and most represent maar-style diatremes that have a vertical- walled volcanic crater of explosive origin, surrounded by a low rim of ejecta. Pyroclastic fall and surge are the two volcanic mechanisms of deposition. There are also deposits formed by hydraulic reworking and resedimentation of material from tephra cones and/or extra-crater fall and surge deposits. The NAKP volcanics, including the ML pipes, contain abundant lapilli and olivine supported in a fine-grained groundmass.
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The youngest rock units consist of rough terra and smooth plains materials. Rough terra occurs as overlapping and intermixed ejecta blankets around dusters of large young craters in the eastern part of the quadrangle. The relief here appears to be higher than elsewhere in the map area, and the occurrence of dense arrays of fresh secondary craters produces a coarsely textured, hummocky surface at a scale of about 10–20 km. The effect of roughness is highlighted by the low sun illumination angle.
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All known eruptions at the volcano have had a Volcanic Explosivity Index (VEI) of 3. Despite its activity, Sangay is located in a remote, uninhabited region; only a large Plinian eruption could threaten occupied areas to its west. Nonetheless, a flank collapse on its eastern side, possible given the volcano's construction and history, could displace nearby forest and possibly affect settlements. Access to the volcano is difficult, as its current eruptive state constantly peppers the massif with molten rock and other ejecta.
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This unit has a complex history of deposition; it was reworked in place and probably includes brecciated plutonic rocks and possibly ancient volcanic flows. Deposition of the intercrater plains material was waning as the next oldest basins (Dostoevskij, Tolstoj) were formed. Partly overlapping their formation was the deposition of the intermediate plains material, probably emplaced partly as distal basin ejecta and partly as volcanic flows. Regional deformation of these plains units by compressive tectonics, forming scarps, was contemporaneous with their deposition.
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Unlike impact craters, pit craters are rimless, often irregularly shaped, steep-sided, and often display no associated ejecta or lava flows. These pit craters are thought to be evidence of shallow volcanic activity and may have formed when retreating magma caused an unsupported area of the surface to collapse, creating a pit. They are analogs of Earth's volcanic calderas. Pit-floor craters may provide an indication of internal igneous processes where other evidence of volcanic processes is absent or ambiguous.
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"Ice rafts" in Conamara Chaos Enhanced-color regional view of Conamara Chaos, showing its location south of the intersection of two large "tripleband" lineae. White areas are ejecta rays from the large (26-km diameter) crater Pwyll 1000 km to the south Conamara Chaos is a region of chaotic terrain on Jupiter's moon Europa. It is named after Connemara () in Ireland due to its similarly rugged landscape. Conamara Chaos is a landscape produced by the disruption of the icy crust of Europa.
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Tephra layers crop out in ice cliffs and seracs and testify to recent eruptions, including the one that deposited the ejecta and lapilli pumice units on the summit. Tephra bands are also found in other glaciers of the region. They form when snow accumulates on top of tephra that fell onto ice and in the case of Mount Melbourne they indicate eruptions during the last few thousand years. Volcanic sediments from Mount Melbourne are also found in Terra Nova Bay.
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This crater produced a broad, wispy ray system that extends for more than 100 km in all directions. The ejecta blanket contains multiple lobate impact melt flows, that extend to over 40 km from the centre of the 9.3 km diameter crater, and that appear dark in contrast to the surrounding material. The crater was named by the IAU in 2015, after Italian planetary scientist Elisabetta Pierazzo. Pierazzo was herself a specialist in impact cratering and the associated production of impact melt.
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USGS Hawaiian Volcano Observatory Deaths attributed to volcanoes frequently have a different cause, for example volcanic ejecta, pyroclastic flow from a collapsing lava dome, lahars, poisonous gases that travel ahead of lava, or explosions caused when the flow comes into contact with water. A particularly dangerous area is called a lava bench. This very young ground will typically break-off and fall into the sea. Areas of recent lava flows continue to represent a hazard long after the lava has cooled.
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The inner wall is noticeably wider in the east, and shallow and worn to the north. The crater floor has been resurfaced, either by ejecta from the Mare Imbrium or by basaltic lava, and is relatively smooth and featureless. The crater lacks a central rise at the midpoint, which may have been buried. The inner sides appear to have been somewhat smoothed down, most likely as a result of minor bombardment and seismic shaking from other impacts in the vicinity.
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Perspective view of Caloris Basin – high (red); low (blue). Enhanced- color image of Munch, Sander and Poe craters amid volcanic plains (orange) near Caloris Basin Craters on Mercury range in diameter from small bowl-shaped cavities to multi-ringed impact basins hundreds of kilometers across. They appear in all states of degradation, from relatively fresh rayed craters to highly degraded crater remnants. Mercurian craters differ subtly from lunar craters in that the area blanketed by their ejecta is much smaller, a consequence of Mercury's stronger surface gravity.
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Bureau of Printing, Manila. A narrower Pansipit River eventually formed from the layer of ejecta from the volcano and a new course was created. The present source of the river on the lake is perhaps north of the old entrance with the new channel joining the old channel about down the river valley. The change in the elevation of the lake also prevented sea water from flowing into the lake thus turning it to freshwater, its marine life evolved and adapted to freshwater living.
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They are larger at all latitudes than single layer ejecta craters. The icy layer has been called by different names: cryosphere, permafrost, and ice-cemented cryosphere. View underneath Phoenix lander towards south foot pad, showing patchy exposures of a bright surface that was later confirmed to be water ice, as predicted by theory and detected by Mars Odyssey. Researchers have analyzed the distribution of both of these craters to determine the thickness of an icy layer that may surround the total surface of Mars.
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The Apollo 14 crew members sampled boulders in the ejecta of Cone crater. These boulders appeared to be layered and fractured breccias, contrasting from the appearance of the surrounding area because of their older age. As these boulders increase in size and number closer to Cone crater, it is believed that they originate from the greatest depth of excavation of Cone crater. These boulders show what is believed to be general characteristics of the Fra Mauro formation: clastic texture, stratification, and jointing or fracturing.
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The ejecta pattern, oblong shape, and location of the central peak indicate the original impact may have been at a low angle from the southeast. Due to its rays, Rutherfurd is mapped as part of the Copernican System.The geologic history of the Moon, 1987, Wilhelms, Don E.; with sections by McCauley, John F.; Trask, Newell J. USGS Professional Paper: 1348. Plate 11: Copernican System (online) The crater was named by and for astrophotographer Lewis Morris Rutherfurd who took the first telescopic photographs of the moon.
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In northeastern Minnesota these iron-banded formations lie immediately under the ejecta layer. One use of the impact layer is as a precise timeline that ties together well- known stratigraphic sequences of the various geographically separated iron ranges. The Sudbury Impact layer lies at a horizon that records a significant change in the character of sediments across the region. The layer marks the end of a major period of banded-iron formation deposition that was succeeded by deposition of fine clastic rocks - commonly black shales.
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Both probes launched successfully in July 1988. The first was lost en route to Mars, whereas the second returned some data and images but failed shortly before beginning its detailed examination of Phobos's surface, including a lander. In 1997 and 1998, the proposed Aladdin mission was selected as a finalist in the NASA Discovery Program. The plan was to visit both Phobos and Deimos, and launch projectiles at the satellites. The probe would collect the ejecta as it performed a slow flyby (~1 km/s).
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The ionisation emission is similar to a planetary nebula but at lower levels of ionisation due to the lower temperatures of the central stars. The strongest lines are [Fe ] and [N ], similar to those from the stellar winds of the stars themselves, but with narrower profiles. Shock waves at the outer edge of the ejecta are heated to millions of kelvin and emit x-ray radiation. The lobes of the Homunculus emit copious radio waves, including emission in the 21 cm line of hydrogen.
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Profile view of the crater Until 1983 there was no evidence of a large impact crater buried beneath the lower part of the Chesapeake Bay and its surrounding peninsulas. The first hint was a layer of ejecta found in a drilling core taken off Atlantic City, New Jersey, about 170 miles to the north. The layer contained the fused glass beads called tektites and shocked quartz grains that are unmistakable signs of a bolide impact. In 1993, data from oil exploration revealed the extent of the crater.
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The eruption wiped out – at least temporarily – all flora and terrestrial fauna of San Benedicto. The fauna included the endemic San Benedicto rock wren which became extinct around 9 AM on August 1. It is unusual for an extinction to be recorded with such precision, and in this case it was only possible because observers were offshore, documenting how the island was blasted with ejecta. However, once the volcanic activity had died down by the spring of 1953, seabirds returned to the island for the breeding season.
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Oblique Lunar Orbiter 5 image, facing west Finsen is a lunar impact crater that is located in the southern hemisphere, on the Moon's far side. It is attached to the southeastern exterior of the walled plain Leibnitz, and the ejecta from Finsen covers the southeastern part of Leibnitz's interior floor. To the southwest of Finsen is another walled plain, Von Kármán, partly overlain by Leibnitz. This is a relatively young impact crater with well- defined features that have not been significantly eroded by subsequent impacts.
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Grotrian is a lunar impact crater that is located on the southern hemisphere on the far side of the Moon. It lies to the north of the huge walled plain Schrödinger, within the radius of that formation's outer blanket of ejecta. The long Vallis Planck formation begins just to the north of Grotrian, and continues to the north-northwest towards Pikel'ner. The outer wall of this crater forms a very nearly circular shape, with the smaller crater Hawke across the southern rim breaking up the symmetry.
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Another multi-ring structure--Heimdall is found to the south-west of Lofn. Geologically Lofn is divided into a number of zones including the flat central floor zone, ring of massifs around it and the outer rings of bright and dark impact ejecta. Lofn was probably formed by an oblique impactor coming from the north-west. The relative shallowness of it is explained by either fragmentation of the impactor prior to the contact with the surface or by the post impact relaxation of Callisto's ductile crust.
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The ejecta featured blocks of medium-grain granodiorite, as well as inclusions of diabase, quartz diorite, granite, aplite, and granophyre. Ashfall layers have been eroded by pyroclastic flows and with time, but they are still visible at Hillman Peak and along the Cleetwood Trail. The Plinian column from the eruption devastated the area hundreds of miles north and northeast of Mazama, but to the southwest and west, little pumice or ash were deposited. The eruption's character changed dramatically as the column of pumice and ash collapsed.
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Caloris ejecta are embayed and partly covered by a plains unit that lies mostly in large, roughly circular depressions, some of which may be ancient degraded basins. This plains material also occurs in the floors of old craters and in small irregular topographic lows. The eastern part of the Shakespeare quadrangle consists mainly of cratered terrain and intercrater plains. Over the whole of the mapped area are scattered fresh craters superposed on other units; in the eastern part the large fresh craters show well- developed bright rays.
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Hilly plains material consists of low, rounded, closely spaced hills with relatively few superposed craters. The hills range in size from 1 to 2 km across and were estimated to have heights of 100 to 200 m by Trask and Guest, who first recognized this unit and named it hilly terrain. The main tracts of hilly material occur in a roughly concentric band outside the Caloris ejecta. It is possible that this unit is associated with Caloris, although apart from geographical distribution, there is no supporting evidence.
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The collision caused ripples in the lunar crust, resulting in the three concentric circular features. The innermost rings of this vast, multi-ringed crater are the inner and outer Montes Rook, and the outermost ring are the Montes Cordillera, in diameter. Outward from here, ejecta extend some from the foot of the mountains and form a rough surface with hummocks and with features radially aligned towards the center. The Apollo program did not sample rocks from Mare Orientale so its precise age is not known.
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Exogenic hypotheses involve one or more large impacts as being responsible for the lowering of the northern plains. Although a multiple-impact origin has been proposed, it would have required an improbable preferential bombardment of the northern hemisphere. It is also unlikely that multiple impacts would have been able to strip ejecta from the northern hemisphere, and uniformly strip the crust to a relatively consistent depth of 3 km. Mapping of the northern plains and the dichotomy boundary shows that the crustal dichotomy is elliptical in shape.
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Scientists believed that the energy of the high-velocity collision would be sufficient to excavate a crater up to wide, larger than the bowl of the Roman Colosseum. The size of the crater was still not known one year after the impact. The 2007 Stardust spacecraft's NExT mission determined the crater's diameter to be . Just minutes after the impact, the Flyby probe passed by the nucleus at a close distance of , taking pictures of the crater position, the ejecta plume, and the entire cometary nucleus.
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Modern theories predict that a (conjectural) asteroid or comet impact on the Moon would create a plume of ejecta rising up from the surface, which is consistent with the monks' description. The impact would be expected to perturb the Moon's motions, and laser rangefinding measurements of its libration in longitude were judged to be of the expected magnitude for such an event. In addition, the location recorded fits in well with the crater's location. Additional evidence of Giordano Bruno's youth is its spectacular ray system.
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This crater is overlain in turn by a pair of craters that lie across the eastern rim. The floor of the crater is level and has most likely been resurfaced by subsequent lava flows, or by fallback and ejecta deposits. This wiped away much of the original structure of the interior, leaving ridges and traces where once lay crater rims. Other lesser craters intrude into the rim, with Desargues M forming a bulge into the southern rim and Desargues A overlying the northern rim.
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These groups appear to have formed simultaneously, as no specific stratigraphic sequence is evident. On the basis of crater clusters of similar appearance in the lunar highlands, which have been interpreted as Imbrium and Orientale basin secondaries (Schultz, 1976; Wilhelms, 1976b; Eggleton, 1981), these crater groups are interpreted to be Caloris Basin secondaries. Following the terminology developed by McCauley and others (1981) we have assigned them to the Van Eyck Formation, Secondary-Crater Facies. These secondaries overlie Dostoevskij ejecta and thus confirm that basin as pre-Caloris.
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Topographic map of Planté based on Apollo 8 imagery Planté is a lunar crater that is situated near the eastern inner wall of the much larger crater Keeler. Just to the east, attached to the exterior of Keeler, is the large crater Heaviside. Planté is located on the far side of the Moon and cannot be viewed directly from the Earth. This crater has a sharp-edged rim and an interior floor that is wider along the southeastern half, possibly due to slumped material or ejecta deposits.
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The area where the official coordinates place this bay has a generally higher albedo than the mare to the south, most likely due to deposits of ejecta from impacts to the north. Early concepts of a Moon landing promoted by Wernher von Braun envisaged the establishment of a permanent lunar base in the Sinus Roris region. These concepts lead, in much modified form, to Project Apollo. Arthur C. Clarke's novel A Fall of Moondust is set in a fictional "Sea of Thirst" located within Sinus Roris.
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The scientists used data from continuing reconnaissance of Mars using the old Mars Odyssey Orbiter and the Mars Reconnaissance Orbiter, discovered 139 LARLE craters ranging in diameter from 1.0 to 12.2 km, with 97 per cent of the LARLE craters are found poleward of 35N and 40S, while remaining mainly traced in the equatorial Medusae Fossae Formation. LARLE craters are characterized by a crater and normal layered ejecta pattern surrounded by an extensive but thin outer deposit which ends in a flame-like shape.
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Helium giants are increasingly favoured as the progenitors of type Ib supernovae, but the progenitors of type Ic supernovae is still uncertain. One proposed mechanism for producing gamma-ray bursts is induced gravitational collapse, where a neutron star is triggered to collapse into a black hole by the core collapse of a close companion consisting of a stripped carbon-oxygen core. The induced neutron star collapse allows for the formation of jets and high-energy ejecta that have been difficult to model from a single star.
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Oblique view of Lalande from Apollo 16, facing north Lalande is a small lunar impact crater that lies in the central part of the visible Moon, on the eastern edge of Mare Insularum. It was named after French astronomer Jérôme Lalande. The crater is surrounded by a high-albedo area of ejecta that extends into a ray system with a maximum radius of over 300 kilometers. The interior wall has a terrace system, and there is a small central rise at the midpoint of the floor.
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Oblique Lunar Orbiter 5 image with Lents at center and Lents C below right, facing west Lents is a small lunar impact crater on the far side of the Moon. It is located within the north-northwestern section of the immense skirt of ejecta that surrounds the Mare Orientale impact basin. To the south is the Montes Cordillera mountain ring, and to the north-northeast is the damaged crater Elvey. This is a bowl-shaped formation with an interior floor that is about half the diameter of the crater.
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The outward expansion of solar ejecta into interplanetary space provides overdensities of plasma that are efficient at scattering high-energy cosmic rays entering the solar system from elsewhere in the galaxy. The frequency of solar eruptive events is modulated by the cycle, changing the degree of cosmic ray scattering in the outer solar system accordingly. As a consequence, the cosmic ray flux in the inner Solar System is anticorrelated with the overall level of solar activity. This anticorrelation is clearly detected in cosmic ray flux measurements at the Earth's surface.
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Oblique view from Lunar Orbiter 5, facing west Pawsey is a worn impact crater that lies next to the northern outer ramparts of the crater Wiener, on the far side of the Moon. To the east-northeast of Pawsey is the large crater Campbell, and farther to the west is Bridgman. This crater is partly overlain by the ejecta from the younger Wiener impact, leaving an uneven formation with edges that have been blanketed by material. There is a small crater along the western rim, and another small, cup-shaped crater along the northeastern edge.
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The Pre-Nectarian period is defined from the point at which the lunar crust formed, to the time of the Nectaris impact event. Nectaris is a multi-ring impact basin that formed on the near side of the Moon, and its ejecta blanket serves as a useful stratigraphic marker. 30 impact basins from this period are recognized, the oldest of which is the South Pole–Aitken basin. This geological period has been informally subdivided into the Cryptic and Basin Groups 1-9, but these divisions are not used on any geological maps.
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A meteorite impacted in Arabia Terra some time between 30 June 2002 and 5 October 2003. A single small crater of about 22.6 meters (about 74 feet) in diameter is surrounded by light and dark-toned ejecta – indicating that this impact excavated to a depth where light colored strata exists. The crater occurs near 20.6 degrees north latitude, 356.8 degrees west longitude, in Arabia Terra. Images of the area show how the impact site appeared to the Mars Odyssey Thermal Emission Imaging System infrared instrument before and after the impact.
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Marine terraces often result from marine erosion along rocky coast lines in temperate regions due to wave attack and sediment carried in the waves. Erosion also takes place in connection with weathering and cavitation. The speed of erosion is highly dependent on the shoreline material (hardness of rock), the bathymetry, and the bedrock properties and can be between only a few millimeters per year for granitic rocks and more than per year for volcanic ejecta. The retreat of the sea cliff generates a shore (wave-cut/abrasion-) platform through the process of abrasion.
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Parts of the crater are also overlain by ejecta from the Mare Orientale basin to the east. The most notable feature in the interior is the tiny, bowl-shaped impact crater Lamarck B. The remainder of the floor forms a rolling, uneven plain. Attached to the southwestern rim is Lamarck A, a large but equally disintegrated crater. Lamarck D is a huge formation that lies to the west of Lamarck A. However, this last feature is also worn to the point where it is barely recognizable as a crater.
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There are two conservation laws at work when a gun is fired: conservation of momentum and conservation of energy. Recoil is explained by the law of conservation of momentum, and so it is easier to discuss it separately from energy. The nature of the recoil process is determined by the force of the expanding gases in the barrel upon the gun (recoil force), which is equal and opposite to the force upon the ejecta. It is also determined by the counter-recoil force applied to the gun (e.g.
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For a ground detonation, approximately 200 tons of soil per kiloton of yield is melted and comes in contact with radiation. The fireball volume is the same for a surface or an atmospheric detonation. In the first case, the fireball is a hemisphere instead of a sphere, with a correspondingly larger radius. The particle sizes range from submicrometer- and micrometer-sized (created by condensation of plasma in the fireball), through 10–500 micrometers (surface material agitated by the blast wave and raised by the afterwinds), to millimeter and above (crater ejecta).
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The rim to the north and east remains relatively circular, but the original rim along the western face has been overlain by satellite craters Klaproth G and Klaproth H, and other impacts. To the south the crater Casatus significantly intrudes into the interior floor. The remaining floor has been resurfaced by some material in the past, possibly fluidized ejecta or lava, leaving a level and nearly featureless surface that is marked only by a multitude of tiny craterlets. If this walled-plain once possessed a central peak, it no longer exists.
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Galilaei has a highly degraded rim and lacks recognizable ejecta. The crater is 137 km (85 mi) in diameter and has a relatively flat floor that lies 3 km below the martian elevation datum. The crater is in a low-lying part of Mars where there are many channels, chaos zones, and craters with outlet channels that provide evidence for climate variability and surface flooding. The crater has an outlet channel named Tana Vallis, which shows that Galilaei once contained a crater lake that overtopped its rim, producing an overland flood.
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Other atmospheric observations included a swirling dark oval of high atmospheric-haze, about the size of the Great Red Spot, near Jupiter's north pole. Infrared imagery revealed aspects of circulation near the poles, with bands of globe-encircling winds, and adjacent bands moving in opposite directions. The same announcement also discussed the nature of Jupiter's rings. Light scattering by particles in the rings showed the particles were irregularly shaped (rather than spherical) and likely originated as ejecta from micrometeorite impacts on Jupiter's moons, probably on Metis and Adrastea.
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Crüger is a lunar impact crater that is located in the western part of the Moon, to the northeast of the much larger walled plain Darwin. The most distinctive feature about this crater is very dark interior floor that is one of the lowest albedo features on the Moon. The surface has been covered in basaltic lava and has only been exposed to a minimal amount of deposition from impact ejecta. The floor is nearly featureless, with only a tiny craterlet near the center and few other even more diminutive impacts.
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Faraday has overlain and damaged the western rim, and this crater in turn has been overlain by several smaller craters. LRO image The rim of Stöfler is worn and eroded, but the outline remains relatively intact except where overlain by Faraday. The smaller Stöfler K intrudes into the northwestern rim, and Stöfler F forms an indentation into the base of the southwestern interior wall. The crater floor has been filled in with deposits, either from lava flows or ejecta from basin impacts, and is relatively flat and featureless in the northwest half.
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This valley intrudes into the southeastern rim of the crater, then continues northwards from the periphery of the northeast rim. Attached to the western rim of Fechner is Fechner T, a small, bowl-shaped crater with a relatively high albedo ray system. This satellite crater is surrounded by a blanket of light-hued ejecta that spills across the southwestern half of Fechner's interior floor. The crater rim of Fechner is relatively worn and eroded, with the eastern half of the rim reshaped due to the valley and proximity to Planck.
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A view of Evans from Lunar Orbiter 5, facing west Evans is the remnant of a lunar impact crater that is located on the far side of the Moon. It lies to the south-southwest of the immense walled plain Hertzsprung, and is located within that impact basin's broad skirt of ejecta. This material has overflowed the northern rim of Evans and the northern part of the interior floor. The southern rim is not as heavily damaged, although it is irregular, eroded, and overlain by a pair of small craterlets.
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A geomorphological map published in 2019 classifies Charon's surface into 16 types, including: blocky terrain, smooth terrain, elevated smooth terrain, rough terrain, mottled terrain, lobate aprons, and Mons, depressed material, craters and crater ejecta. Linear features were classified as catena, crater rim crest, depression margin, graben trace, groove, ridge crest, scarp base, scarp crest, or broad warp. Different time periods were labelled Ozian (older than 4 billion years, exposed in a region titled Oz Terra). The Vulcanian is next and features cryoflows, mainly near the equator in an area called Vulcan Planum.
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He employed granular material physics to describe fragment ejecta behaviour and to predict the impact depth of projectiles as a function of impact velocity. Noting an anomalous behaviour from the experimental observations, he applied the variational perturbation theory to reveal and explain the role played by the increase in mass density during the failure of brittle materials under dynamic compression. In 1999, he accepted a postdoctoral researcher position from the Massachusetts Institute of Technology to enhance his studies in applied mechanics. After his postdoctoral studies, he lectured in ocean engineering at MIT.
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Currently, in advanced countries, most cases of fluoride exposure are due to the ingestion of dental fluoride products. Other sources include glass-etching or chrome-cleaning agents like ammonium bifluoride or hydrofluoric acid, industrial exposure to fluxes used to promote the flow of a molten metal on a solid surface, volcanic ejecta (for example, in cattle grazing after an 1845–1846 eruption of Hekla and the 1783–1784 flood basalt eruption of Laki), and metal cleaners. Malfunction of water fluoridation equipment has happened several times, including a notable incident in Alaska.
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Unlike smooth plains, the origin of inter-crater plains has yet to be well determined. Research and studies have narrowed the origin of inter-crater plains on Mercury down to two hypotheses. The first hypotheses attributes formation from fluidized impact, ejecta, which is the result of a meteorite impacting the surface so hard that it turns to liquid, then liquid debris is ejected into the air and lands, filling in any lower elevation areas or craters. The other hypothesis is that the plains formed from volcanic deposits originating from below the surface of Mercury itself.
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Guthnick is a lunar impact crater that lies on the far side of the Moon's surface from the Earth. However, it is located in the part of the far side that is sometimes brought into sight of the Earth due to libration, although it can only be seen at a low angle and during favorable lighting conditions. Guthnick is situated in the southern portion of the huge skirt of ejecta that surrounds the Mare Orientale impact basin. Less than a crater diameter to the northwest is the slightly larger crater Rydberg.
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Colorful topography of Brashear from the USGS digital atlas This formation is little more than a shallow depression in the lunar surface, its features eroded and blanketed by the ejecta from the relatively fresh crater Antoniadi just to the north. The satellite crater Brashear P lies to the south-southwest. This formation is a heavily worn crater with features that have been almost completely worn away by subsequent impacts. Connected to the southern rim of this crater is a series of valleys and impact craters leading a couple of hundred kilometres to the east.
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This minor planet was named after Austrian geologist Franz Eduard Suess (1867–1941/2), son of geologist Eduard Suess and professor at the Technical College in Prague and superintendent at the Imperial Geological Institute of Vienna. Franz Eduard made fundamental studies on moldavites and coined the term "tektite", which are ejecta from meteor impact events. The official naming citation was published by the Minor Planet Center on 24 January 2000 (). The lunar crater Suess, as well as the crater Suess on Mars, however, are named after his father.
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Satellite experiments have found evidence of positrons and a few antiprotons in primary cosmic rays, amounting to less than 1% of the particles in primary cosmic rays. This antimatter cannot all have been created in the Big Bang, but is instead attributed to have been produced by cyclic processes at high energies. For instance, electron-positron pairs may be formed in pulsars, as a magnetized neutron star rotation cycle shears electron-positron pairs from the star surface. Therein the antimatter forms a wind which crashes upon the ejecta of the progenitor supernovae.
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The dominant feature in the Shakespeare quadrangle is the Caloris Basin, 1,300 km in diameter. This impact basin is the largest and best preserved on the hemisphere of Mercury observed by Mariner 10. Almost the entire eastern half of the basin is in the Raditladi quadrangle; the west half was in the nightside hemisphere of Mercury during all the Mariner 10 passes, and part of the southern half lies in the adjacent Tolstoj quadrangle (Schaber and McCauley, 1980). Surrounding Caloris is a discontinuous annulus of its ejecta deposits, called the Caloris Group.
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It covers large areas in the western, central, and southeastern parts of the quadrangle. There, as in other regions of Mercury, its surface reveals the outlines of many buried crater rim crests and knobby remnants of an older resurfaced terra. This unit has been scoured by many secondary craters that have formed overlapping chains and troughs that contribute to its hummocky texture. The intercrater plains unit is inferred to consist of crater and basin ejecta deposits, volcanic flows, and possible pyroclastic deposits that have partly resurfaced and smoothed older, highly cratered, crustal rocks.
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The unit intergrades to the west and south with intercrater plains material and is interpreted to be of the same origin and composition. The intermediate plains material and smooth plains material probably also consist of mixtures of relatively fine crater ejecta and volcanic materials that appear to form a continuous sequence. Both units are thicker than the intercrater plains unit. The intermediate plains material is widespread in intercrater areas in the west half of the quadrangle and fills floors of older craters and basins in the southern part.
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Goethe Basin is a large circular depression that measures approximately in diameter from rim crest to rim crest. Goethe is bounded on its north and east sides by a gently sloping wall and discontinuous, low, hummocky rim material that may consist of ejecta deposits. These materials are similar to those occurring around the Caloris Basin in the Tolstoj quadrangle (Schaber and McCauley, 1980). On its west side, Goethe is bounded by at least three subparallel ridges or tilted blocks, which are separated by narrow troughs partly filled with smooth plains material.
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The albedo of smooth plains material is higher than that of lunar mare material (Hapke and others, 1975). The similarity in albedo between mercurian smooth plains material and lunar light plains material led Wilhelms to extend the analogy to composition: he suggested that both units consist of impact ejecta similar to the lunar Cayley Formation sampled by Apollo 16. Wilhelms even hypothesized that the source basin for material of the extensive plains of Borealis Planitia “could well be lurking in the darkness beyond the terminator.” A fuller discussion of the problem is given by Strom.
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In the Borealis region, craters are mapped according to the fivefold classification proposed by McCauley and others (1981), which determines Mercurian crater ages on the basis of crater diameter and morphologic degradation. Craters less than about in diameter are not mapped. All basins between and in diameter (including those that have central peaks and peak rings) are mapped as craters. Criteria used to determine impact structures are morphologic crater components such as rays, secondary rays, hummocky rims, various facies of crater ejecta, crater geometry and structure, or a combination of these.
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Scoria may form as part of a lava flow, typically near its surface, or as fragmental ejecta (lapilli, blocks and bombs), for instance in Strombolian eruptions that form steep-sided scoria cones. Chemical analysis of scoria found in Yemen showed that it was mainly composed of volcanic glass with a few zeolites (e.g. clinoptilolite).Preliminary Assessment of Utilization of Al-Jaif Scoria (NW Sana’a, Yemen) for Cement Production Most scoria is composed of glassy fragments, and may contain phenocrysts. The word scoria comes from the Greek σκωρία, skōria, rust.
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Even small caldera-forming eruptions, such as Krakatoa in 1883 or Mount Pinatubo in 1991, may result in significant local destruction and a noticeable drop in temperature around the world. Large calderas may have even greater effects. When Yellowstone Caldera last erupted some 650,000 years ago, it released about 1,000 km3 of material (as measured in dense rock equivalent (DRE)), covering a substantial part of North America in up to two metres of debris. By comparison, when Mount St. Helens erupted in 1980, it released ~1.2 km3 (DRE) of ejecta.
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About 74,000 years ago, this Indonesian volcano released about dense-rock equivalent of ejecta. This was the largest known eruption during the ongoing Quaternary period (the last 2.6 million years) and the largest known explosive eruption during the last 25 million years. In the late 1990s, anthropologist Stanley Ambrose proposed that a volcanic winter induced by this eruption reduced the human population to about 2,000–20,000 individuals, resulting in a population bottleneck. More recently, Lynn Jorde and Henry Harpending proposed that the human species was reduced to approximately 5,000-10,000 people.
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This area and its antipode in the Discovery quadrangle are the only two on Mercury where tensional forces can now be seen to have shaped the surface. The Tolstoj Basin is encompassed by parts of at least three ragged and discontinuous inward-facing scarps. Lineated ejecta is best developed in the vicinity of and beyond the outer scarp, whereas blocky materials occur between the inner and outer scarps. These relations are similar to those around Caloris, although Tolstoj is less than half its size and is much more severely degraded by later impact cratering.
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The bright interior of the basin is noticeably redder than the surrounding plains, which are made of a bluer low reflectance material (LRM). The dark annulus of ejecta around Tolstoj is one of the darkest places on the surface of Mercury. The depth of Tolstoj is estimated to be from the stereo derived digital elevation models based on Mariner 10 images of the planet. This is significantly less than the depth of lunar basins of the similar size indicating that Tolstoj probably has relaxed from its post impact shape.
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Spectroscopic observation of nova ejecta nebulae has shown that they are enriched in elements such as helium, carbon, nitrogen, oxygen, neon, and magnesium. The contribution of novae to the interstellar medium is not great; novae supply only as much material to the Galaxy as do supernovae, and only as much as red giant and supergiant stars. Recurrent novae such as RS Ophiuchi (those with periods on the order of decades), are rare. Astronomers theorize, however, that most, if not all, novae are recurrent, albeit on time scales ranging from 1,000 to 100,000 years.
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12, pp. 1147–48. Open access. This hypothesis is suggested as a means to explain the severity of the Cretaceous–Paleogene extinction event, as the earth impact of an asteroid about 10 km wide which precipitated the extinction is not regarded as sufficiently energetic to have caused the level of extinction from the initial impact's energy release alone. The global firestorm winter, however, has been questioned in more recent years (2003–2013) by Claire Belcher, Tamara GoldinAtmospheric Interactions During Global Deposition of Chicxulub Impact Ejecta Tamara Joan Goldin, dissertation, 2008.
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The region of Guinevere Planitia gives great insight to venusian tectonics and how the planet manages its heat. The nature of these structures also provides clues to the styles of volcanism, which is related to composition, volatile content, interaction with crust during magma movement, and the structure of the crust and lithosphere. By using geomorphic properties observed in the images taken, the terrain can be categorized into three types of geologic material: ridge terrain, plains materials, and volcanoes. There are crater materials locally that include ejecta, rim, and floor deposits from nine recognized craters.
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Shaded relief topographic map of the crater. Oblique Lunar Orbiter 5 image, looking west; north sector of crater buried by Leibnitz ejecta Von Kármán is a large lunar impact crater that is located in the southern hemisphere on the far side of the Moon. The crater is about in diameter and lies within an immense impact crater known as the South Pole–Aitken basin of roughly in diameter and deep. Von Kármán is the site of the first soft-landing on the lunar far side by the Chinese Chang'e 4 spacecraft on 3 January 2019.
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Similar features may be seen in ejecta blankets of Martian craters, suggesting impacts into a volatile (ice)-rich target material. Furthermore, both craters appear crisp and feature terraces. Gula has a prominent central peak; Achelous instead may show the remnant of a collapsed central peak or a central pit that is not fully formed. On lower- resolution images taken under higher sun illumination angle, both craters are shown to have extended bright rays, especially Achelous, which demonstrates that these two craters are younger than the respective surrounding landscape.
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Part of dark Nicholson Regio is at lower left, bounded on its upper right by Harpagia Sulcus. Gula and Achelous (bottom), in the grooved terrain of Ganymede, with ejecta "pedestals" and ramparts. Ganymede's surface is a mix of two types of terrain: very old, highly cratered, dark regions and somewhat younger (but still ancient), lighter regions marked with an extensive array of grooves and ridges. The dark terrain, which comprises about one-third of the surface, contains clays and organic materials that could indicate the composition of the impactors from which Jovian satellites accreted.
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On 11 December 2010, Steve Larson of the Catalina Sky Survey detected a comet-like appearance to asteroid Scheila: it displayed a "coma" of about magnitude 13.5. Inspection of archival Catalina Sky Survey observations showed the activity was triggered between 11 November 2010 and 3 December. Imaging with the 2-meter Faulkes Telescope North revealed a linear tail in the anti-sunward direction and an orbital tail, indicative of larger slower particles.Richard Miles's posting on Yahoo minor planet mailing list (MPML) When first detected it was unknown what drove the ejecta plumes.
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LRO mosaic Giordano Bruno is a lunar impact crater on the far side of the Moon, just beyond the northeastern limb. It lies in an area that can be viewed during a favorable libration, although the area is viewed from the side and not much detail can be seen. It lies between the craters Harkhebi to the northwest and Szilard to the southeast. When viewed from orbit, Giordano Bruno is at the center of a symmetrical ray system of ejecta that has a higher albedo than the surrounding surface.
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The crater is deeply eroded and its original size must be inferred by indirect means. Some authors estimate an original diameter of up to , while other suggest a smaller size, perhaps only , closer to that of the depression in which Lake Acraman is centred. The larger size estimate would imply an energy release of 5.2 × 106 megatons of TNT. The impact event is estimated to have occurred about 580 million years ago during the Ediacaran; this age is not derived from the crater itself but from the position of ejecta within nearby sedimentary basins.
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Oblique Lunar Orbiter 5 view of Leuschner (lower left) with Catena Leuschner (row of craters center to upper right), facing west Leuschner is a lunar impact crater that is located on the Moon's far side, to the northwest of the Montes Cordillera. It lies to the north of the crater Grachev, in the outer skirt of ejecta surrounding the Mare Orientale impact basin. This is a circular crater with a rim that has only been lightly eroded by subsequent impacts. Within the interior floor is a central ridge formation.
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In 1989, the Voyager 2 spacecraft observed cryovolcanoes (ice volcanoes) on Triton, a moon of Neptune, and in 2005 the Cassini–Huygens probe photographed fountains of frozen particles erupting from Enceladus, a moon of Saturn. The ejecta may be composed of water, liquid nitrogen, ammonia, dust, or methane compounds. Cassini–Huygens also found evidence of a methane-spewing cryovolcano on the Saturnian moon Titan, which is believed to be a significant source of the methane found in its atmosphere. It is theorized that cryovolcanism may also be present on the Kuiper Belt Object Quaoar.
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Cross-section through a stratovolcano (vertical scale is exaggerated): Stratovolcanoes or composite volcanoes are tall conical mountains composed of lava flows and other ejecta in alternate layers, the strata that gives rise to the name. Stratovolcanoes are also known as composite volcanoes because they are created from multiple structures during different kinds of eruptions. Strato/composite volcanoes are made of cinders, ash, and lava. Cinders and ash pile on top of each other, lava flows on top of the ash, where it cools and hardens, and then the process repeats.
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False color air photo of Cinder Cone and the Fantastic Lava Beds. Around the mid-18th century a series of eruptions produced Cinder Cone in the northeast corner of the park, mantling an area of with ejecta in the process. Ash falling on the streams of lava pouring from the cone's east flank formed the Painted Dunes. A flow of quartz- studded basalt lava (the Fantastic Lava Beds) poured from the Cinder Cone and dammed the streams that fed nearby Butte Lake to the north, forming Snag Lake to the south.
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"I think there's much more interest in driving around the perimeter of the rim," said Arvidson. The rover survived so long this goal was accomplished, and by 2016 it was decided to not only enter Endevaour crater but also explore, for the first time in history what is thought to be a water carved gully on Mars (update:2016). Upon arriving at Endeavour, Opportunity almost immediately began discovering Martian phenomena not previously observed. On sol (August 22, 2011) the rover began examining Tisdale 2, a large ejecta block.
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This has suggested to some that the basin was not formed by a typical high-velocity impact, but may instead have been formed by a low- velocity projectile around 200 km in diameter that hit at a low angle (about 30 degrees or less), and hence did not dig very deeply into the Moon. Putative evidence for this comes from the high elevations north-east of the rim of the South Pole–Aitken basin that might represent ejecta from such an oblique impact. The impact theory would also account for magnetic anomalies on the Moon.
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In multiple locations the rays lie at glancing angles, instead of forming a true radial dispersal. An extensive pattern of smaller secondary craters can also be observed surrounding Copernicus, a detail that was depicted in a map by Giovanni Cassini in 1680. Some of these secondary craters form sinuous chains in the ejecta. In 1966 the crater was photographed from an oblique angle by Lunar Orbiter 2 as one of 12 "housekeeping" pictures that were taken to advance the roll of film between possible astronaut landing sites being surveyed.
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Most of the ejecta that came out of a volcano is gas. About 60% is just carbon (C) and water vapor (H2O). About 30% is sulfur (S). The sulfur mixes with the water vapor to form sulfuric acid which is notorious for eating away at almost anything from plants to rocks. For the 99% percent of plutons that didn't make it to the surface they cooled to form granite monoliths under these volcanoes. When subduction activities ceased about 55 million years ago, these volcanoes were subject to erosion due to their steep slopes.
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The Lunar Crater Observation and Sensing Satellite (LCROSS) mission is co-manifested with LRO. It was selected as a secondary payload in 2006, and management of the program was assigned to Ames Research Center (ARC). The mission will explore a permanently shadowed region of a lunar pole by crashing the spent Centaur rocket upper stage of the Atlas V launch vehicle into a dark crater. The composition of the ejecta plume will be observed by a shepherding spacecraft, which will itself crash-land 4 minutes later, creating a second plume.
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At least seven basins in or partly in the Michelangelo quadrangle postdate or are contemporaneous with the last stages of deposition of intercrater plains material. Dostoevskij (–44°, 176°) displays only one ring; presumably the inner peak ring is buried by plaint material. The ejecta from this basin may be mapped as far as 450 km from the rim; several secondary crater chains occur southeast of the rim. Although Dostoevskij was considered a type example of a c3 large crater (McCauley and others, 1981), crater counts indicate that it is much older.
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Lamproite pipes operate similarly to kimberlite pipes, except that the boiling water and volatile compounds contained in the magma act corrosively on the overlying rock, resulting in a broader cone of eviscerated rock (the ejection of this rock also forms a tuff ring, like kimberlite eruptions). This broad cone is then filled with volcanic ash and materials. Finally, the degassed magma is pushed upward, filling the cone. The result is a funnel shaped deposit of volcanic material (both solidified magma, and ejecta) which appears mostly flat from the surface.
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The interior floor of d'Alembert is a relatively level surface, at least in comparison with the rough terrain that surrounds the crater rim. It is marked with a number of small crater impacts, the largest being d'Alembert G and d'Alembert E toward the eastern rim. In the southwest, the floor is more irregular due to the outer rampart and layers of ejecta from Slipher. A pair of shallow clefts in the floor surface radiate away from this crater, beginning near the midpoint of d'Alembert and reaching half-way toward the inner wall.
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Much of the interior floor of this walled plain has been resurfaced by lava, leaving a level, nearly featureless surface with the same low albedo as the dark lunar mare to the northwest. However the southeastern part of the floor is more irregular, because ejecta from Finsen covers part of it. The dark floor is covered in places by streaks of ray material, and several tiny craterlets. The small crater Leibnitz X near the northwest inner wall has been flooded by lava, leaving only a roughly circular rim projecting above the surface.
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Infrared emission also reveals the presence of un-ionised material such as molecular hydrogen (H2) and argon. In many planetary nebulae, molecular emission is greatest at larger distances from the star, where more material is un-ionised, but molecular hydrogen emission in NGC 6543 seems to be bright at the inner edge of its outer halo. This may be due to shock waves exciting the H2 as ejecta moving at different speeds collide. The overall appearance of the Cat's Eye Nebula in infrared (wavelengths 2–8 μm) is similar in visible light.
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Hypernovae are now widely accepted to be supernovae with ejecta having a kinetic energy larger than about , an order of magnitude higher than a typical core collapse supernova. The ejected nickel masses are large and the ejection velocity up to 99% of the speed of light. These are typically of type Ic, and some are associated with long-duration gamma-ray bursts. The electromagnetic energy released by these events varies from comparable to other type Ic supernova, to some of the most luminous supernovae known such as SN 1999as.
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Models for hypernova focus on the efficient transfer of energy into the ejecta. In normal core collapse supernovae, 99% of neutrinos generated in the collapsing core escape without driving the ejection of material. It is thought that rotation of the supernova progenitor drives a jet that accelerates material away from the explosion at close to the speed of light. Binary systems are increasingly being studied as the best method for both stripping stellar envelopes to leave a bare carbon-oxygen core, and for inducing the necessary spin conditions to drive a hypernova.
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Geologic map of an area of the formation (Click to enlarge and see color key). During Apollo 14, astronauts Alan Shepard and Edgar Mitchell recovered ejecta material from the Cone crater impact, which is believed to have excavated Imbrium impact material from a possible depth of about . Most of the samples returned from the Moon from Fra Mauro are classified as breccias from the vicinity of Cone crater. Studies conducted upon samples from Apollo 14 have shown that the samples do not support the possibility that the landing site is floored by volcanic rocks, or basalts.
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The landing site for Apollo 14 is a heavily craterized terrain, and one of the science goals of the mission was to sample ejecta from the impact that formed Mare Imbrium. Nördlinger Ries is an easily accessible, large impact crater, making it a convenient analog for lunar craters. Because of this, it was used as a location to train Apollo 14 astronauts, so that they would be able to investigate lunar impact structures and related rocks. Astronauts Alan Shepard and Edgar Mitchell, as well as Apollo 14 backup astronauts Eugene Cernan and Joe Engle trained here from August 10 to August 14, 1970.
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Except for the case of zero-recoil, the counter-recoil force is smaller than the recoil force but lasts for a longer time. Since the recoil force and the counter-recoil force are not matched, the gun will move rearward, slowing down until it comes to rest. In the zero- recoil case, the two forces are matched and the gun will not move when fired. In most cases, a gun is very close to a free-recoil condition, since the recoil process generally lasts much longer than the time needed to move the ejecta down the barrel.
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Sudbury is an exception to the normal process of forming minerals in the Shield since the Sudbury Basin is an ancient meteorite impact crater. Ejecta from the meteorite impact was found in the Rove Formation in May 2007. The nearby but less-known Temagami Magnetic Anomaly has striking similarities to the Sudbury Basin. This suggests it could be a second metal-rich impact crater.3-D Magnetic Imaging using Conjugate Gradients: Temagami anomaly Retrieved on 2008-03-12 In northeastern Quebec, the giant Manicouagan Reservoir is the site of an extensive hydroelectric project (Manic-cinq, or Manic-5).
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The volcanic area of the Tibesti Mountains is located entirely in Chad; it covers about a third of the total area of the Tibesti Mountains and is responsible for between of rock. The rest of the Tibesti Mountains consists of volcanic plateaus (tarsos in the Tedaga language), located between elevation, as well as lava fields and ejecta deposits. The plateaus are larger and more numerous in the east: the Tarso Emi Chi, the Tarso Aozi, the Tarso Ahon to the north of Emi Koussi, and the Tarso Mohi. In the center is Tarso Ourari at about .
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The fourth phase saw the formation of Tarso Toussidé and the lava flows of Tarso Tôh in the west, the collapse of the caldera on the summit of Tarso Voon and associated ejecta deposits in the center, and the decline in lava production in the east, with the exception of Emi Koussi, which continued to rise. The end of this phase coincided with the beginning of the Holocene. The Yirrigué volcano emitted pyroclastic ignimbrite up to in all directions, filling in valleys. In the fifth phase, volcanic activity became much more localized and lava production continued to wane.
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Lunar Reconnaissance Orbiter Wide Angle Camera image of Reiner Gamma Another view of Reiner Gamma swirls Mare Ingenii Firsov crater, from Apollo 10 Lunar swirls are enigmatic features found across the Moon's surface, which are characterized by having a high albedo, appearing optically immature (i.e. having the optical characteristics of a relatively young regolith), and (often) having a sinuous shape. Their curvilinear shape is often accentuated by low albedo regions that wind between the bright swirls. They appear to overlay the lunar surface, superposed on top of craters and ejecta deposits, but impart no observable topography.
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The allowable timescale of formation of Callisto lies then in the range 0.1 million–10 million years. ejecta of an ancient impact The further evolution of Callisto after accretion was determined by the balance of the radioactive heating, cooling through thermal conduction near the surface, and solid state or subsolidus convection in the interior. Details of the subsolidus convection in the ice is the main source of uncertainty in the models of all icy moons. It is known to develop when the temperature is sufficiently close to the melting point, due to the temperature dependence of ice viscosity.
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Limestone quarry in Brønnøy, Norway Lime is a calcium-containing inorganic mineral composed primarily of oxides, and hydroxide, usually calcium oxide and/ or calcium hydroxide. It is also the name for calcium oxide which occurs as a product of coal-seam fires and in altered limestone xenoliths in volcanic ejecta. The word lime originates with its earliest use as building mortar and has the sense of sticking or adhering. These materials are still used in large quantities as building and engineering materials (including limestone products, cement, concrete, and mortar), as chemical feedstocks, and for sugar refining, among other uses.
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Earthquakes shattered the ground hundreds of miles away and within seconds ejecta (cloud of ash, rock fragments, gases and droplets of molten rock) began to spread around the globe. It is estimated that at ground zero the earthquake would have registered 10.2 on the Richter scale. Seas covered the Rove Formation area and the Sudbury impact generated huge tsunamis. To put the Sudbury meteorite impact in perspective, the Chicxulub impact on the Yucatán Peninsula occurred from an object perhaps 60% the size of the Sudbury impactor; the results of this impact caused the worldwide extinction of many species (including dinosaurs).
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A sequence of MERLIN observation of the X-ray binary GRS 1915+105 taken over a few days. In 1994, GRS 1915+105 became the first known galactic source that ejects material with apparent faster-than-light or superluminal velocities. Observations with high resolution radio telescopes such as VLA, MERLIN, and VLBI show a bi-polar outflow of charged particles, which emit synchrotron radiation at radio frequencies. These studies have shown that the apparent superluminal motion is due to a relativistic effect known as relativistic aberration, where the intrinsic velocity of ejecta is actually about 90% the speed of light.
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He further posits that the mass extinction of dinosaurs occurred within 33,000 years of this date. In April 2019 a paper was published in PNAS which describes evidence from a fossil site in North Dakota that the authors say provides a "postimpact snapshot" of events after the asteroid collision "including ejecta accretion and faunal mass death". The team found that the tektites that had peppered the area were present in amber found on the site and were also embedded in the gills of about 50 percent of the fossil fish. They were also able to find traces of iridium.
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The soil discarded by Mulumura explained the piles of meteoritic iron around the craters and the presence of ejecta rays (which are unique to terrestrial impacts but are now gone due to prospecting at the site). This probably relates to Dreaming stories about ancestral lizard beings from the area of Henbury station near the Finke River, just north of the crater field. The Parks and Wildlife Commission of the Northern Territory give the Arrernte name for the crater field as Tatyeye Kepmwere (or Tatjakapara). In 1980, the conservation reserve was listed on the now-defunct Register of the National Estate.
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Although the detonation never occurred, the site was radioactively contaminated by an experiment to estimate the effect on water sources of radioactive ejecta landing on tundra plants and subsequently washed down and carried away by rains. Material from a 1962 nuclear explosion at the Nevada Test Site was transported to the Chariot site in August 1962, used in several experiments, then buried. Thirty years later, the disposal was discovered in archival documents by a University of Alaska researcher. State officials immediately traveled to the site and found low levels of radioactivity at a depth of two feet (60 cm) in the burial mound.
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The rays may extend for lengths up to several times the diameter of their originating crater, and are often accompanied by small secondary craters formed by larger chunks of ejecta. Ray systems have been identified on the Moon, Earth (Kamil Crater), Mercury, and some moons of the outer planets. Originally it was thought that they existed only on planets or moons lacking an atmosphere, but more recently they have been identified on Mars in infrared images taken from orbit by 2001 Mars Odysseys thermal imager. Gratteri crater, a rayed crater on Mars that was imaged by THEMIS at night.
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This is an eroded formation with a rim that has been worn and reshaped by impacts. This is particularly so in the south where the rim has been modified and supplemented by adjacent crater formations and several small craters that lie along the rim. The interior floor is relatively level in places, but, partly due to overlapping ejecta, is somewhat rough and irregular in others, particularly in the southern half. A pair of small but prominent craters lies on the interior surface, with Rayleigh D just to the south of the crater midpoint and the smaller Rayleigh B situated in the western half.
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Vallis Schrödinger (Latin for "Schrödinger Valley") is a long, nearly linear valley that lies on the far side of the Moon. It is oriented radially to the huge Schrödinger basin and most likely was formed during the original impact that created Schrödinger. Oblique view from Apollo 15 showing Vallis Schrödinger cutting across Sikorsky crater, while both are at the terminator The valley is shaped like a long groove in the lunar surface. It begins at the outer rampart of ejecta surrounding Schrödinger and continues to the north- northwest until it crosses the rim of the crater Moulton.
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The Italian–Dutch satellite BeppoSAX, launched in April 1996, provided the first accurate positions of gamma-ray bursts, allowing follow-up observations and identification of the sources. Several models for the origin of gamma-ray bursts postulated that the initial burst of gamma rays should be followed by slowly fading emission at longer wavelengths created by collisions between the burst ejecta and interstellar gas.Paczynski 1993 This fading emission would be called the "afterglow". Early searches for this afterglow were unsuccessful, largely because it is difficult to observe a burst's position at longer wavelengths immediately after the initial burst.
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This conclusion resulted from new measurements: The velocity of the LISM (local interstellar medium) relative to the Sun's was previously measured to be 26.3 km/s by Ulysses, whereas IBEX measured it at 23.2 km/s. This phenomenon has been observed outside the Solar System, around stars other than the Sun, by NASA's now retired orbital GALEX telescope. The red giant star Mira in the constellation Cetus has been shown to have both a debris tail of ejecta from the star and a distinct shock in the direction of its movement through space (at over 130 kilometers per second).
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In 1997, Shoemaker and his wife, Carolyn, named asteroid 6585 after O'Keefe. Prior to the moon landings O'Keefe developed a theory that tektites, natural glass objects found in discrete strewn fields around the world, are actually volcanic ejecta from the Moon. He suggested that explosive, hydrogen-driven lunar volcanoes may be the mechanism that launched the tektites to Earth. After the moon landings his claim was apparently supported by a chemical analysis of a portion of lunar sample 12013 retrieved by Apollo 12 astronaut Pete Conrad that showed a similar major element composition to some tektites found in Southeast Asia.
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Fainter planetary rings can form as a result of meteoroid impacts with moons orbiting around the planet or, in case of Saturn's E-ring, the ejecta of cryovolcanic material. The composition of ring particles varies; they may be silicate or icy dust. Larger rocks and boulders may also be present, and in 2007 tidal effects from eight 'moonlets' only a few hundred meters across were detected within Saturn's rings. The maximum size of a ring particle is determined by the specific strength of the material it is made of, its density, and the tidal force at its altitude.
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Heinrich Holland argues that the absence of manganese deposits during the pause between Paleoproterozoic and Neoproterozoic BIFs is evidence that the deep ocean had become at least slightly oxygenated. The "Canfield ocean" model proposes that, to the contrary, the deep ocean became euxenic and transport of reduced iron was blocked by precipitation as pyrite. Banded iron formations in northern Minnesota are overlain by a thick layer of ejecta from the Sudbury Basin impact. An asteroid (estimated at 10 km across) impacted into waters about 1,000 m deep 1.849 billion years ago, coincident with the pause in BIF deposition.
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The components used to define the crater ages are rays, secondary craters, ejecta facies, central peaks and rings, rim form, and inner terraces. As a crater ages, the number of superposed craters increases and each of the morphologic elements becomes more subdued. Volcanic activity also may bury or destroy certain crater components, but the crater may still be dated by the preservation of the remaining rim. On the basis of mapping in this quadrangle and in the adjacent Tolstoj quadrangle (Schaber and McCauley, 1980), the Caloris impact is considered to have occurred in late c3 time (McCauley and others, 1981).
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Troughs and ridges are present throughout the quadrangle. Where the troughs are not clearly radial to crater or basin centers, they may be grabens; however, in most places they are difficult to distinguish from linear gouges produced by impact ejecta at low-angle ballistic trajectories. Some ridges resemble those on the lunar maria, but generally they are less sharply defined. Ridges interpreted to be buried rim crests of two ancient basins are partly visible almost due north of Beethoven basin; the probable centers of the basins are near latitude 11° S., longitude 127° and latitude 2° N., longitude 124°.
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They traveled to Cinco Crater to sample at three geology stations, with the goal of finding ejecta from the South Ray crater. After they traveled to collect samples at the nearby Wreck Crater, the rover's navigation system failed, forcing the two astronauts to manually navigate back to the LM. On their return trip, they saw the LM at a distance of , and stopped at the ALSEP location to take soil samples. They returned to the LM and finished their EVA after 7:23 on the lunar surface. The third EVA began on the morning of April 23.
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Plate 11: Copernican System (online) The brightest feature of this crater is the steep central peak. Sections of the interior floor appear relatively level, but Lunar Orbiter photographs reveal the surface is covered in many small hills, streaky gouges, and some minor fractures. The crater has a terraced outer wall, roughly or polygonal in shape, and covered in a bright blanket of ejecta. These spread out into bright rays to the south and south-east, suggesting that Aristarchus was most likely formed by an oblique impact from the northeast, and their composition includes material from both the Aristarchus plateau and the lunar mare.
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Mead is classified as a multi-ring crater with its innermost, concentric scarp being interpreted as the rim of the original crater cavity. No inner peak-ring of mountain massifs is observed on Mead. The presence of hummocky, radar- bright crater ejecta crossing the radar-dark floor terrace and adjacent outer rim scarp suggests that the floor terrace is probably a giant rotated block that is concentric to, but lies outside, the original crater cavity. The flat, somewhat brighter inner floor of Mead is interpreted to result from considerable infilling of the original crater cavity by impact melt and/or by volcanic lavas.
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Differences in crater density as well as embayment relations in the Borealis region show that the intercrater plains material and the smoother intermediate plains material are younger than many craters in the area northeast of crater Turgenev, and older than smooth plains material in Borealis Planitia. The relative age of intercrater plains material has a bearing on its origin. If very old, intercrater plains material may consist of anorthosite derived from a magma ocean such as may have existed on the Moon (Wood and others, 1970). If emplaced during later stages of mercurian evolution, it may consist of basin ejecta or lava flows.
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However, planetwide, the morphologic evidence for an impact origin rather than a volcanic one is not compelling. Whether or not either hypothesis is eventually substantiated, the emplacement of intercrater plains material likely began during an early stage of intense accretionary bombardment (Guest and O’Donnell, 1977) and lasted until the time of formation of intermediate plains material. This general conclusion seems to be supported in the Borealis region by the relative scarcity of craters between 30 km and 60 km in diameter. This scarcity may indicate resurfacing by crater overlap and blanketing by crater ejecta or resurfacing by lava flows.
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After marveling at the view (including South Ray) from the side of Stone Mountain, which Duke described as "spectacular," the astronauts gathered samples in the vicinity. After spending 54 minutes on the slope, they climbed aboard the lunar rover en route to the day's second stop, station five, a crater across. There, they hoped to find Descartes material that had not been contaminated by ejecta from South Ray Crater, a large crater south of the landing site. The samples they collected there, although their origin is still not certain, are, according to geologist Don Wilhelms, "a reasonable bet to be Descartes".
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The next stop, station six, was a blocky crater, where the astronauts believed they could sample the Cayley Formation as evidenced by the firmer soil found there. Bypassing station seven to save time, they arrived at station eight on the lower flank of Stone Mountain, where they sampled material on a ray from South Ray Crater for about an hour. There, they collected black and white breccias and smaller, crystalline rocks rich in plagioclase. At station nine, an area known as the "Vacant Lot," which was believed to be free of ejecta from South Ray, they spent about 40 minutes gathering samples.
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Superposition of crater ejecta over parts of intercrater plains in other areas indicates that some large craters formed in a preexisting intercrater plains unit. On the other hand, the intercrater plains material partly postdates some of the major cratering events on Mercury, according to apparent superposition relations. In particular, the unit appears to overlap the entire northwest side of the Tolstoj Basin, a feature indicating that the intercrater plains in this region probably do not represent the remains of the primordial surface of the planet. A complex history of contemporaneous craters and plains formation is therefore suggested.
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Undoubtedly, the ejecta also influences a large part of the as-yet-unseen terrain to the west. A stratigraphic and structural comparison between the Orientale and Caloris Basins has been made by McCauley. McCauley and others have proposed a formal rock stratigraphy for the Caloris Basin that we have adopted on the present map. This stratigraphy is patterned after that used in and around the Orientale Basin on the MoonScott, D. H., McCauley, J. F., and West, M. N., 1977, Geologic map of the west side of the Moon: U.S. Geological Survey Miscellaneous Investigations Series Map I-1034, scale 1:5,000,000.
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Andromedid meteors sometimes appear as red fireballs. The Andromedids were associated with the most spectacular meteor showers of the 19th century; the storms of 1872 and 1885 were estimated to have a peak rate of two meteors per second (a zenithal hourly rate of 10,000), prompting one Chinese astronomer to compare the meteors to falling rain. The Andromedids had another outburst on December 3–5, 2011, the most active shower since 1885, with a maximum zenithal hourly rate of 50 meteors per hour. The 2011 outburst was linked to ejecta from Comet Biela, which passed close to the Sun in 1649.
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Among the deleterious effects resulting from a major impact event is a cloud of fine dust ejecta blanketing the planet, blocking some direct sunlight from reaching the Earth's surface thus lowering land temperatures by about within a week and halting photosynthesis for several months (similar to a nuclear winter). The mean time between major impacts is estimated to be at least 100 million years. During the last 540 million years, simulations demonstrated that such an impact rate is sufficient to cause 5–6 mass extinctions and 20–30 lower severity events. This matches the geologic record of significant extinctions during the Phanerozoic Eon.
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The impact nature is documented by impact melt rocks, suevite, abundant polymictic and monomictic breccias, breccia dikes (dike breccias), extensive megabreccias, impact ejecta, dislocated megablocks, peculiar geological structures in the rim and central uplift zones, and shock metamorphism. Shock effects comprise melt glass, diaplectic glass from quartz and feldspar, planar deformation features (PDFs) in quartz and feldspar and moderate shock effects like intense kink banding and multiple sets of planar fractures (PFs) in quartz, multiple sets of kink bands in mica, and intense micro-twinning in calcite. Moderately developed shatter cones add to the impact signature.
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The most prominent of these is the satellite crater Milne K, which is located just to the south of the midpoint. Overlapping the southern rim of K is the smaller Milne L. In the northeast part of the floor is an unusual tight formation of 10–12 small impacts that almost resembles a cluster of grapes. The crater floor is somewhat irregular in the northwestern part, where the prominent crater Scaliger intrudes into the outer rim, leaving ejecta across the floor. Other nearby craters include Alden to the north, Parkhurst to the west, Schaeberle to the northeast, and Bjerknes to the south.
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Protoplanetary nebula known as Emperor Seiwa taken by Hubble's Advanced Camera for Surveys. During the ensuing protoplanetary nebula phase, the central star's effective temperature will continue rising as a result of the envelope's mass loss as a consequence of the hydrogen shell's burning. During this phase, the central star is still too cool to ionize the slow-moving circumstellar shell ejected during the preceding AGB phase. However, the star does appear to drive high- velocity, collimated winds which shape and shock this shell, and almost certainly entrain slow-moving AGB ejecta to produce a fast molecular wind.
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Ashbrook is a large lunar impact crater that is located in the vicinity of the south pole on the far side of the Moon, and so cannot be viewed directly from the Earth. The eastern face of the crater has been overlain by the similar- sized Drygalski, and more than half the interior floor of Ashbrook is covered by the outer ramparts and ejecta of Drygalski. To the northwest is the walled plain Zeeman. The surviving outer rim of Ashbrook is worn and eroded by subsequent impacts, although much of the original formation is still visible.
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Bilharz (top), Atwood (lower left), and Naonobu (lower right), from Apollo 11 Atwood is a small earth moon impact crater that is located on the Mare Fecunditatis, to the northwest of the prominent crater Langrenus. It forms a triple-crater formation with Naonobu attached to the north rim and Bilharz near the west rim. Atwood lies near the edge of the outer ramparts of Langrenus, and the ejecta forms low ridges attached to the south rim of Atwood. Within the crater interior is a low central peak that joins a ridge line to the north rim of the crater.
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Numerous extensive lava flows, several more than in length, also mark the surface. The materials produced by this volcanism make up Io's thin, patchy atmosphere and Jupiter's extensive magnetosphere. Io's volcanic ejecta also produce a large plasma torus around Jupiter. Io played a significant role in the development of astronomy in the 17th and 18th centuries; discovered in January 1610 by Galileo Galilei, along with the other Galilean satellites, this discovery furthered the adoption of the Copernican model of the Solar System, the development of Kepler's laws of motion, and the first measurement of the speed of light.
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The ridges associated with the intermediate plains unit are best interpreted as tectonic in origin because they extend into adjacent exposures of intercrater plains material and, more significantly, because they transect ejecta, rims, and floors of craters. The ridges range in length from about 50 km to many hundreds of kilometers, are sinuous to lobate in plan, and generally trend about north-south. Most are asymmetric, with one slope steeper than the other, and at places they can be more logically referred to as rounded scarps. Commonly, an individual ridge changes along trend from symmetric ridge to asymmetric ridge to rounded scarp.
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Continuous ejecta deposits are less extensive, and secondary craters are more sharply defined and clustered nearer their primary crater. Also on Mercury, accentuated secondary craters form prominent crater chains radial to large craters. Craters within the Kuiper quadrangle increase in complexity as they increase in size from simple bowl-shaped craters to complex craters with central peaks to multiringed basins. Kuiper (11° S., 31.5°) is a moderate-size crater with a central peak cluster; Brunelleschi (9° S., 22.5°) exhibits an incomplete ring of peaks; and Rodin (22° N., 18°) is a well-developed double-ringed basin.
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Such duration of luminosity would not be possible without heating by internal radioactive decay, which is provided by r-process nuclei near their waiting points. Two distinct mass regions ( and ) for the r-process yields have been known since the first time dependent calculations of the r-process. Because of these spectroscopic features it has been argued that such nucleosynthesis in the Milky Way has been primarily ejecta from neutron-star mergers rather than from supernovae. These results offer a new possibility for clarifying six decades of uncertainty over the site of origin of r-process nuclei.
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View of St. George (slightly above left of center) facing south from the rim of Hadley Rille (Geology Station 9) St. George is a feature on Earth's Moon, a crater in the Hadley–Apennine region. Astronauts David Scott and James Irwin drove their rover onto what was suspected to be its ejecta blanket in 1971, on the Apollo 15 mission, during EVA 1. They collected samples to the northeast of the crater, at Geology Station 2 of the mission. St. George crater is located on the west slope of Mons Hadley Delta and approximately 4 km southwest of the Apollo 15 landing point.
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Mega tsunami of the world oceans: Chevron dune formation, micro-ejecta, and rapid climate change as the evidence of recent oceanic bolide impacts: T. Beer (ed.), Geophysical Hazards, p. 197-227; Springer Publ. Part of the evidence they cite for this hypothesis is that the sediments contain tiny marine fossils; however, such fossils can be moved by the wind, just like sand. The impact idea is controversial not only because chevrons are similar to wind-blown landforms found far from the ocean, but also because it is unlikely that there have been enough large impacts and landslides to explain the observed chevrons.
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Analysis of the burst's afterglows suggested two models to explain the burst's afterglow. In the first, the burst's ejecta were collimated into a jet with a half-angle greater than 6° and interacted with a high-density medium. In the second, the jet had a half-angle greater than 2° and interacted with a low-density medium. If the characteristics of the first model, which were similar to those of GRB 050724, are representative of all short GRBs, then the emission jets of short GRBs are less collimated and less energetic than those of long GRBs.
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The standard model of long-duration gamma- ray bursts (GRBs) holds that these explosions are ultra-relativistic (initial \gamma greater than approximately 100), which is invoked to explain the so- called "compactness" problem: absent this ultra-relativistic expansion, the ejecta would be optically thick to pair production at typical peak spectral energies of a few 100 keV, whereas the prompt emission is observed to be non- thermal.Cenko, S. B. et al., iPTF14yb: The First Discovery of a Gamma-Ray Burst Afterglow Independent of a High-Energy Trigger, Astrophysical Journal Letters 803, 2015, L24 (6 pp). Subatomic particles called muons, have a relatively high Lorentz factor and therefore experience extreme time dilation.
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This material forms an irregular striation in the surface that is radial to the Mare Orientale basin. As a result, only the northeast part of the crater is somewhat intact; the remainder just forms an uneven depression in the surface that is covered in long ridges and gouges. The most notable feature in this section is the small bowl-shaped crater Lagrange D. The surviving section of the rim is worn and eroded, forming an arc-shaped range of low ridges in the surface. The interior floor in this section is relatively level, but even this surface contains traces of the Mare Orientale ejecta.
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Pluto's smaller moons, including Hydra, were thought to have formed from debris ejected from a massive collision between Pluto and another Kuiper belt object, similarly to how the Moon is believed to have formed from debris ejected by a large collision of Earth. The ejecta from the collision would then coalesce into the moons of Pluto. It was thought that Hydra had initially formed at a closer proximity to Pluto, and its orbit had undergone changes through tidal interactions. In this case, Hydra along with the smaller moons of Pluto would have migrated outwards with Charon into their current orbits around the Pluto-Charon barycenter.
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Maury lunar crater Antonia Maury was a member of the American Astronomical Society and the Royal Astronomical Society. In 1943, she was awarded the Annie Jump Cannon Award in Astronomy by the American Astronomical Society. The lunar crater Maury and a number of smaller ejecta craters are co-named for Antonia Maury. They were originally named for her cousin, Commander Matthew Fontaine Maury, United States and later Confederate Navies and are, perhaps, the only lunar features shared by two cousins. In 1978, the Revised MK Spectral Atlas for Stars Earlier Than the Sun honored “Antonia C. Maury, Master Morphologist of Stellar Spectra” in its dedication.
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Mikro Profitis Ilias is located on the northern part of the island of Santorini, between Cape Kolumbo to the north and Cape Skaros to the immediate south. The volcanic ridge consists of a northern and southern peak, and the ridge itself lies above a large lava dome. The rock that makes up the ridge is non-volcanic and predates the 1610 BC Minoan eruption of Thera, though the immense amount of volcanic ejecta generated by the eruption did greatly expand the existing ridge line. The northern peak stands at 319.6 meters tall, while the southern peak rests one meter lower at 318 meters tall.
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There is very strong evidence that comets have previously been fragmented and collided with Jupiter and its satellites. During the Voyager missions to the planet, planetary scientists identified 13 crater chains on Callisto and three on Ganymede, the origin of which was initially a mystery. Crater chains seen on the Moon often radiate from large craters, and are thought to be caused by secondary impacts of the original ejecta, but the chains on the Jovian moons did not lead back to a larger crater. The impact of SL9 strongly implied that the chains were due to trains of disrupted cometary fragments crashing into the satellites.
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The incline of this equatorial plane from the observer's line of sight leaves mostly just the polar cap visible. This region would then be approaching the observer as indicated by the overall blueshift of the spectrum. Furthermore, the presence of ejecta from the polar cap at various velocities would account for the observed high velocity wings in the Balmer series. The behavior of the Hα/Hβ ratio, which decreased for a little over a month before shooting up to saturated levels and remaining high months after, was one of many spectral characteristics, also including distinct forbidden lines, that made V1309 Scorpii distinct from classical novae and more similar to red novae.
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43-56 The eruptive vent formed next to the medieval village of Tripergole on the shores of the then-much larger Lake Lucrino. The thermal bath village, which had been inhabited since ancient Roman times and was home to notable Roman-era buildings including Cicero's villa, was completely buried by ejecta from the new cinder cone. Tripergole's ruins and its important thermal springs completely disappeared under Monte Nuovo such that the exact location of the village can no longer be identified.Il Villaggio di Tripergole - archeoFlegrei (in Italian) Volcanologists feared another eruption between 1969 and 1984, when there were again earthquakes and changes in land elevations in the area.
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Just to the north of the rim is the small crater Aitken A, which is surrounded by an ejecta blanket of lighter-albedo material. The interior floor has been resurfaced in the past by a darker lava flow, especially in the southern half. There are also several small crater impacts on the eastern floor, an arcing central ridge line just to the east of the midpoint, and a line of smaller ridges in the western half. This crater lies along the northern rim of the immense South Pole-Aitken Basin, which was named after this crater and the southern lunar pole, two extreme points of the Basin.
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The Karangtengah inscription, dated 824 CE mentioned that King Indra of Sailendra has built a sacred building named Venuvana which means "bamboo forest". Dutch archaeologist JG de Casparis has connected the temple mentioned in Karangtengah inscription with Mendut temple. However, another suggestion presented by Soekmono argued that the Karangtengah inscription was probably refer to the Ngawen temple instead, based upon the etymological link between the name Ngawen village and Venuvana, for both words contains reference to "bamboo". The temple's actual base was buried two metres beneath the current ground level, suggest that the temple was probably covered by Mount Merapi volcanic ejecta for over a thousand years.
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Like many other impact structures in the world, such as Nördlinger Ries, the Vredefort crater, or the Sudbury Basin, the origin of the Azuara structure has been debated, and Spanish geologists still remain opposed to an impact origin. Cortés A. L., Diaz-Martínez E., Sanz-Rubio E., Martínez-Frías J. and Fernández C. (2002) "Cosmic impact versus terrestrial origin of the Azuara structure (Spain): A review." Meteoritics & Planetary Science 37: 875-894. In their opinion the shock effects are tectonic features, the impact ejecta (Pelarda Formation) are Quaternary alluvial fans and impact breccias and dike breccias are interpreted as karst features and soil formations.
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Oblique view of Mons Hadley, including Hadley Rille (lower right), from orbit Hadley C crater, with ejecta filling in part of Hadley Rille Mons Hadley is a massif in the northern portion of the Montes Apenninus, a range in the northern hemisphere of the Moon. It has a height of above the adjacent plain and a maximum diameter of 25 km at the base. To the southwest of this mountain is a valley that served as the landing site for the Apollo 15 expedition. To the southwest of this same valley is the slightly smaller Mons Hadley Delta (δ) peak with a height of about 3.5 km above the valley floor.
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The term "clastogenic" refers to volcanic eruptions which cause a particular type of ejecta. : _Illustrative sentence_ : "The complex features of this eruption can be explained by rapid deposition of coarse pyroclasts near the vent and the subsequent flowage of clastogenic lavas which were accompanied by a high eruption plume generating pumice falls and/or pyroclastic flows."Yasui, Maya and Takehiro Koyaguchi. "Sequence and eruptive style of the 1783 eruption of Asama Volcano, central Japan: a case study of an andesitic explosive eruption generating fountain-fed lava flow, pumice fall, scoria flow and forming a cone," Journal Bulletin of Volcanology (Kasan). Vol. 66, No. 3 (March 2004). pp. 243-262.
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Lechatelierite also forms as the result of high pressure shock metamorphism during meteorite impact cratering and is a common component of a type of glassy ejecta called tektites. Most tektites are blobs of impure glassy material, but tektites from the Sahara Desert in Libya and Egypt, known as Libyan desert glass, are composed of almost pure silica that is almost pure lechatelierite.Libyan Desert Glass on Mindat High pressure experiments have shown that shock pressures of 85 GPa are needed to produce lechatelierite in quartz grains embedded in granite.C. Schrand and A. Deutsch, 1998, Formation of Lechatelierite and Impact Melt Glasses in Experimentally Shocked Rocks, Lunar and Planetary Science XXIX 1671.
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Close-up of an Abalos Colles mound The Abalos Colles stratigraphy shows similar characteristics with the Rupes Tenuis basal unit, and it is considered a remnant of a larger, contiguous ancient north polar basal unit. The Abalos Colles formation is considered to be the result of large-scale erosion episodes of the Rupes Tenuis basal unit. Probable erosion mechanisms include crater impact which formed ejecta that subsequently covered and protected the ancient basal unit. Conical mounds with flat or cratered tops could have been formed by layer accumulations on top of impact craters which then eroded to varying degrees, depending on the size of the original crater.
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Binary stars which are both visual and spectroscopic binaries also can have their distance estimated by similar means, and don't suffer from the above geometric uncertainty. The common characteristic to these methods is that a measurement of angular motion is combined with a measurement of the absolute velocity (usually obtained via the Doppler effect). The distance estimate comes from computing how far the object must be to make its observed absolute velocity appear with the observed angular motion. Expansion parallaxes in particular can give fundamental distance estimates for objects that are very far, because supernova ejecta have large expansion velocities and large sizes (compared to stars).
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The vent radius and water content of magma indicate that the average volume discharge rate of the Plinian eruption and ignimbrite was 1–3 × 105 m3/s (1–3 × 108 kg/s). A total bulk ejecta of 120 km3 was derived from bulk volumes of pumice fall and ignimbrite of 83 km3 and 37.5 km3, respectively. The ignimbrite-forming eruption may have lasted one and a half to four days (35–104 hours), while the Plinian eruption may have lasted three to nine and a half days (77–230 hours). The total duration of the eruption may have been four and a half to fourteen days (111–333 hours).
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She manages to take off despite her tattered wings, leaving the dead male behind. Smaller animals hide underground while the larger animals are forced to flee. In Mongolia, forty-five minutes since the impact, the ejecta cloud rolls in from the east, increasing the temperature around Mongolia by several degrees every second until it reaches 300°, causing three Charonosaurus and a pair of Saurornithoides to use a cave for shelter (unenthusiastically with each other as well). The temperatures return to normal after five hours, and the Saurornithoides run outside to feast on a Charonosaurus corpse, while two of the surviving Charonosaurus travel to the watering hole.
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These craters range in age from c1 to c3 and, on a minor scale, their ejecta blankets provide stratigraphic horizons useful for the relative dating of material units in their vicinity. Two of the youngest of the double-ringed craters, Durer (lat 22° N., long 119°) and Vivaldi (lat 14° N., long 86°), have prominent and nearly continuous inner rings whose diameters measure about half that of their outer rings. Unlike some of the lunar multiringed structures, no vestiges of additional rings are apparent around these craters. Central peaks are common within craters of c3 and c4 age, rare in craters of c2 age.
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Possibly the plains units on Mercury are similar to the Cayley Formation on the Moon and consist largely of finely divided ejecta materials. Whatever the origin and composition of the plains units in the Beethoven quadrangle, they represent late stages in the crustal evolution of this region. Other differences between the Moon and that part of Mercury observed in this quadrangle are the absence in Beethoven of distinct highlands and lowlands, as well as the preservation in the quadrangle of secondary crater chains around older craters and basins (Scott, 1977). The geologic history of Mercury has been summarized by Guest and O’Donnell (1977), Davies and others, and Strom.
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The scientific consensus is that the asteroid impact at the K–Pg boundary left megatsunami deposits and sediments around the area of the Caribbean Sea and Gulf of Mexico, from the colossal waves created by the impact. These deposits have been identified in the La Popa basin in northeastern Mexico, platform carbonates in northeastern Brazil, in Atlantic deep-sea sediments, and in the form of the thickest-known layer of graded sand deposits, around , in the Chicxulub crater itself, directly above the shocked granite ejecta. The megatsunami has been estimated at more than tall, as the asteroid fell into relatively shallow seas; in deep seas it would have been tall.
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V1280 Scorpii (or Nova Scorpii 2007) is a nova observed in February 2007 in the constellation Scorpius, just south of M62. The nova was a 9th magnitude object when it was discovered independently by Yuji Nakamura and Yukio Sakurai from Japan, around February 4, and peaked at magnitude 3.9 on February 17. Announced by the IAU in Electronic Telegram No. 835 and Circular No. 8803 23 days after discovery, dust formation was found to be occurring in the ejecta, consistent with the classification of the event as a CO nova. This dust formation peaked between 36 and 45 days from the wind that was mainly ejected 10.5 days after the event.
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After Apollo 13 returned, it was decided that its landing site, near Cone crater in the Fra Mauro formation, was scientifically more important than Littrow. The Fra Mauro formation is composed of ejecta from the impact event that formed Mare Imbrium, and scientists hoped for samples that originated deep under the Moon's surface. Cone crater was the result of a young, deep impact, and large enough to have torn through whatever debris was deposited since the Imbrium Event, which geologists hoped to be able to date. Landing at Fra Mauro would also allow orbital photography of another candidate landing site, the Descartes Highlands, which became the landing site for Apollo 16.
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In spite of their violence, usually the amount of material ejected in novae is only about of a solar mass, quite small relative to the mass of the white dwarf. Furthermore, only five percent of the accreted mass is fused during the power outburst. Nonetheless, this is enough energy to accelerate nova ejecta to velocities as high as several thousand kilometers per second—higher for fast novae than slow ones—with a concurrent rise in luminosity from a few times solar to 50,000–100,000 times solar. In 2010 scientists using NASA's Fermi Gamma-ray Space Telescope discovered that a nova also can emit gamma-rays (>100 MeV).
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Because total momentum is conserved, this mass of high velocity ejecta impels the rest of the tamper-pusher to recoil inwards with tremendous force, crushing the fusion fuel and the spark plug. The tamper-pusher is built robustly enough to insulate the fusion fuel from the extreme heat outside; otherwise the compression would be spoiled. Ablation mechanism firing sequence. Rough calculations for the basic ablation effect are relatively simple: the energy from the primary is distributed evenly onto all of the surfaces within the outer radiation case, with the components coming to a thermal equilibrium, and the effects of that thermal energy are then analyzed.
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Two intergrown crystals (1.5 x 1 x 0.5 cm) from Koksha Valley, Badakhshan Province, Afghanistan Clinohumite is a product of contact metamorphism and is commonly found as indistinct grains embedded in limestone. Its type occurrence is within the limestone ejecta of the Mount Vesuvius volcano complex near Naples, Italy, where clinohumite was discovered in 1876. The aforementioned gem-quality occurrences of Pamir and Taymyr were discovered only recently: the former in the early 1980s, and the latter in 2000. These deposits are scarce and only sporadically mined, so clinohumite remains one of the rarest gemstones with only a few thousand carats known to exist in private collections.
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Ridges may have been formed by several processes, including tectonism and extrusion, or they may be buried crater-rim segments. Several large ridges may represent uplift of plains materials by normal faulting. Other ridges are arcuate to circular, which suggests that they are segments of old, subdued crater and basin rims. Near Boccaccio (centered at lat 81° S., long 30°), ridges are domical in cross section and have smooth tops with small irregular or rimless craters along their crests; they appear to overlap both a c3 and a c1 crater (FDS l66751). In turn, these ridges are superposed by c3 craters and c4 ejecta.
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Ordinarily, rough terra material would be subdivided and mapped as individual ejecta blankets around and belonging to particular craters. In this eastern region, however, the closely grouped craters have about the same age, and it has not been possible to distinguish the boundaries between their aprons in many places. Smooth plains material covers the floors of numerous craters in all age classifications. Its surface is scoured by secondary craters from classes c4 and c5 craters at many places in the eastern part of the quadrangle and, within the crater Homer (1° S., 37° ), by secondaries from the class c3 craters Titian (3° S., 42° ) and Handel (4° N., 34° ).
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The South Cluster, a crater cluster located to the south of the Apollo 15 site near Mons Hadley Delta, is believed to have formed as a result of a secondary impact, or the impact of ejecta/debris from a larger impact elsewhere on the Moon, probably the crater Autolycus about northwest of the cluster's location. This meant that the Apollo 15 astronauts were able to sample material from other parts of the lunar surface without traversing a great distance. The feature also allowed the astronauts to sample material that was originally located deep within the Moon. The south rim of Dune crater within the cluster was visited by the astronauts.
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Sangay's approximately 500,000-year-old history is one of instability; two previous versions of the mountain were destroyed in massive flank collapses, evidence of which still litters its surroundings today. Due to its remoteness, Sangay hosts a significant biological community with fauna such as the mountain tapir, giant otter, Andean cock-of-the-rock and king vulture. Since 1983, its ecological community has been protected as part of the Sangay National Park. Although climbing the mountain is hampered by its remoteness, poor weather conditions, river flooding, and the danger of falling ejecta, the volcano is regularly climbed, a feat first achieved by Robert T. Moore in 1929.
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We determined a reference crater density for Caloris in the Shakespeare quadrangle in order to correlate basin ages to that stratigraphic datum. The Beethoven Basin (–20°, 124°), partly exposed in the Michelangelo quadrangle, consists of one ring 660 km in diameter. The exact age of Beethoven is uncertain; the density of superposed primary impact craters suggests a post-Caloris, late c3 age, but it may be as old as early c2 age due to the large range of error in the crater age estimate. The ejecta from Beethoven are very extensive east and southeast of the basin rim and are mappable as far as 600 km downrange from the rim.
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A landing at Tycho was thought to be too dangerous because of the rough terrain found there, a landing on the far side in Tsiolkovskiy would add the expense of communications satellites necessary to maintain contact between the crew and ground control during surface operations, and a landing in Copernicus was regarded as low priority. Taurus–Littrow was eventually selected with the objectives of sampling ancient highland material and young volcanic material in the same landing site. The Taurus–Littrow site offered both of these in the form of highland material in the Tycho ejecta sampled and the prospect that some of the craters in the area could be volcanic vents.
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However, after a more detailed apprasial of the seismic data, Allen and Stewart gave a more cautious estimate of the age as between 74 – 45 million years (Late Cretaceous – Eocene). The stratigraphic method of estimating the age of a crater is somewhat crude and imprecise, and the result is questioned by Underhill's non-impact hypothesis. Assuming an impact origin, other possible ways of dating the event include looking for evidence of ejecta material such as tektites, and deposits from the hypothesised tsunami, which might be found anywhere around the North Sea basin. As well as allowing a more accurate age determination, finding such evidence would also strengthen the impact hypothesis.
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However, on June 27, 1998, an outburst of meteors radiating from Boötes, later confirmed to be associated with Pons-Winnecke, was observed. They were incredibly long-lived, with trails of the brightest meteors lasting several seconds at times. Many fireballs, green-hued trails, and even some meteors that cast shadows were observed throughout the outburst, which had a maximum zenithal hourly rate of 200–300 meteors per hour. Two Russian astronomers determined in 2002 that material ejected from the comet in 1825 was responsible for the 1998 outburst. Ejecta from the comet dating to 1819, 1825, and 1830 was predicted to enter Earth's atmosphere on June 23, 2004.
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The present Aso Caldera formed as a result of four huge caldera eruptions occurring over a range of 90,000–300,000 years ago. The caldera, one of the largest in the world, contains the city of Aso as well as Takamori and Minamiaso enclosing the caldera extends about 18 km east to west and about 25 km north to south. Viewpoints from the somma overlooking the caldera are perched upon lava formed before the volcanic activity which created the present caldera. Ejecta from the huge caldera eruption 90,800 years ago covers more than 600 km3 and roughly equals the volume of Mount Fuji; it is presumed that the pyroclastic flow plateau covered half of Kyushu.
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In November the level of the lava located in the craters was very high, which resulted in an overflow in the upper part of the Sciara del Fuoco, which has increased Strombolian activity and has caused several explosions in the early December as well. The heights of ejecta were intense at Crater 1. Afterward, it reached 200m above Crater 1, and the explosions left magma closely to the crater's rim. At local time 18.30 (UTC+1) on December 28, a not usual activity characterized by a 300m long eruptive break occurred, causing the break of the northern wall of Crater 1, displacing the North West upper eastern part of the Sciara del Fuoco wall.
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Daedalus on the Moon's far side The other major geologic process that has affected the Moon's surface is impact cratering, with craters formed when asteroids and comets collide with the lunar surface. There are estimated to be roughly 300,000 craters wider than on the Moon's near side alone. The lunar geologic timescale is based on the most prominent impact events, including Nectaris, Imbrium, and Orientale, structures characterized by multiple rings of uplifted material, between hundreds and thousands of kilometers in diameter and associated with a broad apron of ejecta deposits that form a regional stratigraphic horizon. The lack of an atmosphere, weather and recent geological processes mean that many of these craters are well- preserved.
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Silverthrone is part of the Pemberton Volcanic Belt, which is circumscribed by a group of epizonal intrusions. At another deeply eroded caldera complex called Franklin Glacier Complex, the Pemberton Volcanic Belt merges with the Garibaldi Volcanic Belt, a northwest-trending belt of volcanic cones and fields extending from near the Canada–United States border east of Vancouver on the British Columbia Coast. The intrusions are thought to be subvolcanic bodies associated with a volcanic front that was active in the Miocene, during early stages of subduction of the Juan de Fuca Plate. With the notable exception of King Island, all the intrusive and eruptive rocks are calc-alkaline, mainly granodioritic bodies and dacite ejecta.
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The flow initially produces an approximately hemispherical cavity that continues to grow, eventually producing a paraboloid (bowl-shaped) crater in which the centre has been pushed down, a significant volume of material has been ejected, and a topographically elevated crater rim has been pushed up. When this cavity has reached its maximum size, it is called the transient cavity. Herschel Crater on Saturn's moon Mimas The depth of the transient cavity is typically a quarter to a third of its diameter. Ejecta thrown out of the crater do not include material excavated from the full depth of the transient cavity; typically the depth of maximum excavation is only about a third of the total depth.
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The resultant structure is called a simple crater, and it remains bowl-shaped and superficially similar to the transient crater. In simple craters, the original excavation cavity is overlain by a lens of collapse breccia, ejecta and melt rock, and a portion of the central crater floor may sometimes be flat. Multi-ringed impact basin Valhalla on Jupiter's moon Callisto Above a certain threshold size, which varies with planetary gravity, the collapse and modification of the transient cavity is much more extensive, and the resulting structure is called a complex crater. The collapse of the transient cavity is driven by gravity, and involves both the uplift of the central region and the inward collapse of the rim.
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After the eruption, the population was reduced to about 34,000 due to massive emigration. Volcanologists observed an eruption pattern observed during the 1948–1952 eruptions (a cycle of four phases) beginning with a short period of emission of steam from the crater and avalanches of volcanic materials, followed by explosions or steam blast with emission of heavy clouds of steam, ash and other fragmentary volcanic materials with a strong possibility of the development of pyroclastic flows. The third phase involves eruption of incandescent materials, emission of ash and steam in large amounts, formation of flows and occasional minor crater outbursts, and finally a decrease in steam and other ejecta from the crater.
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Even so, recoil calculated in this manner is only the starting point in a comparison with the .357 Magnum cartridge, since the latter is used in a revolver, in which the recoil energy is due to the bullet and propellant less ejecta escaping through the cylinder gap, while the .357 SIG cartridge is used in a semi-automatic pistol with recoil operation; here, a significant portion of the recoil energy is diverted to cycle the action, effectively prolonging the recoil-phase pulse. Of course, other considerations affect the user's perceived recoil, such as the weight of the weapon, front to back balance, moving mass, height difference between the shooter's grip parallel to the barrel, and grip.
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Pulsed lasers which provide a high-power burst of energy for a short period are very effective in some laser cutting processes, particularly for piercing, or when very small holes or very low cutting speeds are required, since if a constant laser beam were used, the heat could reach the point of melting the whole piece being cut. Most industrial lasers have the ability to pulse or cut CW (continuous wave) under NC (numerical control) program control. Double pulse lasers use a series of pulse pairs to improve material removal rate and hole quality. Essentially, the first pulse removes material from the surface and the second prevents the ejecta from adhering to the side of the hole or cut.
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The unit was initially interpreted by the Geological Survey to be a conglomerate with clasts derived from mafic dykes. Later interpretations invoked a volcanic origin for the unit, based on the presence of pieces of green devitrified glass, with pyroclastic flow, peperite, tuff and lahar all being proposed. When shocked quartz, a higher than expected concentration of platinum group metals and the presence of a non-terrestrial chromium isotope were all identified in the unit, it was reinterpreted as part of an impact ejecta blanket. Evidence for a meteorite impact close to Ullapool was published by a combined team of scientists from the University of Oxford and the University of Aberdeen, in March 2008.
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147–148 On the other hand, grains are seen to have recently formed in the vicinity of nearby stars, in nova and supernova ejecta, and in R Coronae Borealis variable stars which seem to eject discrete clouds containing both gas and dust. So mass loss from stars is unquestionably where the refractory cores of grains formed. Most dust in the Solar System is highly processed dust, recycled from the material out of which the Solar System formed and subsequently collected in the planetesimals, and leftover solid material such as comets and asteroids, and reformed in each of those bodies' collisional lifetimes. During the Solar System's formation history, the most abundant element was (and still is) H2.
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The oldest activity of the Andagua volcanic field occurred between 400,000 and 64,000 years ago and has been identified close to Chivay in the Colca Valley. Three separate generations of volcanic activity have been defined, a Pleistocene generation, a Pleistocene-Holocene generation and a Holocene generation, with about 3-4 vents forming every ten thousand years. The eruptions of the Andagua volcanic field cones have been accompanied by the emission of slow-moving lava flows and ballistic ejecta which reached less than distance from the vents; estimated volcanic explosivity indexes are 0-2 and the volcanic activity has been described as Strombolian eruptions or phreatomagmatic and accompanied by small eruption columns. Hawaiian eruptions and Strombolian eruptions generated scoria cones.
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However, Earth's oldest ocean-floor crust is only 200 million years old as it is continually being destroyed and renewed by spreading and subduction. Furthermore, craters produced by very large impacts may be masked by extensive flood basalting from below after the crust is punctured or weakened. Yet, subduction should not be entirely accepted as an explanation for the lack of evidence: as with the K-T event, an ejecta blanket stratum rich in siderophilic elements (such as iridium) would be expected in formations from the time. A large impact might have triggered other mechanisms of extinction described below, such as the Siberian Traps eruptions at either an impact site or the antipode of an impact site.
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The Caloris group is a set of geologic units on Mercury. McCauley and othersMcCauley, J. F., Guest, J. E., Schaber, G. G., Trask, N. J., and Greeley, Ronald, 1980, Stratigraphy of the Caloris Basin, Mercury: Icarus, 1980 have proposed the name “Caloris Group” to include the mappable units created by the impact that formed the Caloris Basin and have formally named four formations within the group, which were first recognized and named informally by Trask and Guest. Like the Imbrium and Orientale Basins on the Moon, Caloris Basin is surrounded by an extensive and well-preserved ejecta blanketGuest, J. E., and O’Donnell, W. P., 1977, Surface history of Mercury: A review: Vistas in Astronomy, v. 20, p. 273–300.
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It consists of long, hilly ridges and grooves that are subradial to the Caloris Basin and are extensively embayed by smooth plains. The inner boundary of the Van Eyck is generally coincident with the weak outer Caloris scarp. The Van Eyck is similar in morphology but somewhat more degraded than the Fra Mauro Formation around the Imbrium Basin on the Moon; secondary cratering and ballistic deposition of ejecta from Caloris undoubtedly played an important role in its emplacement. It is difficult to define individual secondary craters within the Van Eyck, but at a distance of about one basin diameter, numerous clusters and chains of moderately well preserved craters occur that are interpreted as far-flung Caloris secondary craters.
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Mariner 10 photomosaic The Beethoven quadrangle is located in the equatorial region of Mercury, in the center of the area imaged by Mariner 10. Most pictures of the quadrangle were obtained at high sun angles as the Mariner 10 spacecraft receded from the planet. Geologic map units are described and classified on the basis of morphology, texture, and albedo, and they are assigned relative ages based on stratigraphic relations and on visual comparisons of the density of superposed craters. Crater ages are established by relative freshness of appearance, as indicated by topographic sharpness of their rim crests and degree of preservation of interior and exterior features such as crater floors, walls, and ejecta aprons.
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Some of Miranda's terrain is possibly less than 100 million years old based on crater counts, while sizeable regions possess crater counts that indicate ancient terrain. While crater counts suggest that the majority of Miranda's surface is old, with a similar geological history to the other Uranian satellites, few of those craters are particularly large, indicating that most must have formed after a major resurfacing event in its distant past. Craters on Miranda also appear to possess softened edges, which could be the result either of ejecta or of cryovolcanism. The temperature at Miranda's south pole is roughly 85 K, a temperature at which pure water ice adopts the properties of rock.
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Before the mission of Lunar Prospector lunar satellite, it was commonly thought that these KREEP materials had been formed in a widespread layer beneath the crust. However, the measurements from the gamma-ray spectrometer on-board this satellite showed that the KREEP-containing rocks are primarily concentrated underneath the Oceanus Procellarum and the Mare Imbrium. This is a unique lunar geological province that is now known as the Procellarum KREEP Terrane. Basins far from this province that dug deeply into the crust (and possibly the mantle), such as the Mare Crisium, the Mare Orientale, and the South Pole–Aitken basin, show only little or no enhancements of KREEP within their rims or ejecta.
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In the late stages of hydrogen burning, mass loss is extremely high due to the high luminosity and enhanced surface abundances of helium and nitrogen. As hydrogen burning ends and core helium burning begins, massive stars transition very rapidly to the Wolf–Rayet stage with little or no hydrogen, increased temperatures, and decreased luminosity. They are likely to have lost over half their initial mass at this point. It is unclear whether triple-alpha helium fusion has started at the core of Eta Carinae A. The elemental abundances at the surface cannot be accurately measured, but ejecta within the Homunculus are around 60% hydrogen and 40% helium, with nitrogen enhanced to ten times solar levels.
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Three widespread units are recognized within the Victoria quadrangle. These are, from oldest to youngest, intercrater plains material, intermediate plains material, and smooth plains material. In addition, central peak, floor, rim, and ejecta materials related to the numerous craters and basins larger than about 20 km in diameter are mapped. The simplicity of the stratigraphic scheme is at least in part due to deficiencies in the data base; the history of plains formation almost certainly is more complex than our threefold division indicates, but we were not able to define consistent criteria of albedo, texture, and cratering for more than three plains units because of the highly variable quality of available pictures.
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Apparent differences may be the result of resolution of the imaging system, and small viewing and illumination angles that do not allow inspection of the surface under varied conditions. Real differences may be the result of Mercury's size, gravitational field, proximity to the Sun, internal composition and structure, or timing of major volcanic episodes relative to the decrease in impact craters. Surface differences include the preservation of secondary craters around older craters and basins, and the absence of recognizable textured and lineated ejecta blankets such as those surrounding the Imbrium and Orientale Basins on the Moon. Possible differences in volcanic features include the absence of widespread dark mare-type deposits, volcanic domes and cones, and sinuous rilles.
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They were fed through numerous dikes, which also gave rise to small scoria cones and spatter cones, and were emplaced non- contemporaneously. A tuff cone rises from the lava field and is formed by monogenetic volcano ejecta, including lava bombs encasing granite fragments and bombs large enough to leave craters in the ash they fell in. Ropy basalt lava flows with an uncertain source vent, and a undissected scoria cone rise above the lava field and complete the Edmonson Point system. The Adelie Penguin Rookery lava field was erupted about 90,000 years ago, and its emplacement may have been accompanied by the emission of tephra recorded in the Talos Dome ice core.
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North of this area, a somewhat subdued valley segment continues to the northwest from 40.5°N to about 42.5°N (northwest of the crater Lowbury) where it is locally buried by impact crater ejecta and young (Amazonian-aged) plains material. This northern valley segment gradually loses its identity amid the narrow grabens of Tantalus Fossae. The elevation of the valley floor ranges from 885 m above datum (Mars "sea" level) in the south to 100 m or less in the north, where the northern segment of the valley begins to lose its definition. In cross-sectional profile, the valley is U-shaped to rectangular, with depths ranging from 20 to 50 m.
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The western extreme is approximately 116° W, on the far side of the Moon. The northern part of the range lies just to the south of the lunar equator, while the southern extent reaches about 38° S. The inner face of the range is distinguished by an uneven, ring-shaped plain surrounding the Montes Rook, while the outer extent apparently consists of a wide blanket of ejecta features deposited during the formation of the Mare Orientale. These have formed various ridges and valleys radial to the mare, and have heavily modified nearby pre-existing crater formations. Along the inner side of the range to the northeast is a small lunar mare feature named the Lacus Autumni, or Autumn Lake.
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Salão (also referred to as Solão historically) derives its name from the term for a mixture of clay, sand and tephra derived from pyroclastic projectiles. The zone of Salão, which occupies the space between the Riberinha Graben and Cedros Plateau is an area of deposits of lapilli particulars, or tephra projectiles smaller than 64 mm. The name Salão refers to the historical local common name for these materials; in current Portuguese taxonomy, Salão, literally means "large hall" or "living room", and the reference to volcanic ejecta is not familiar. The parish is located on the north coast of Faial, between Riberinha and Cedros, linked to other communities by the Regional Road E.R. 1-1ª, that encircles the island and connects it to the city of Horta.
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Lunar sample 61016, better known as "Big Muley" Some theories have been stated that presume the proto-Earth had no large moons early in the formation of the Solar System, 4.425 billion years ago, Earth being basically rock and lava. Theia, an early protoplanet the size of Mars, hit Earth in such a way that it ejected a considerable amount of material away from Earth. Some proportion of these ejecta escaped into space, but the rest consolidated into a single spherical body in orbit about Earth, creating the Moon. The hypothesis requires a collision between a proto-Earth about 90% of the size of present Earth, and another body the diameter of Mars (half of the terrestrial diameter and a tenth of its mass).
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Since 1994 it has been hypothesized that Azuara is only part of a much larger multiple impact event (Azuara impact event), comprising also an elongated impact basin suggested to have resulted from the impact of a string of impactors. This Rubielos de la Cérida basin bears all evidence of impact features like morphological signature, polymictic and monomictic breccias, megabreccias, ejecta deposits, shock metamorphism, suevites and impact melt rocks.Ernstson, K., Claudin, F., Schüssler, U., Anguita, F. and Ernstson, T. 2001. Impact melt rocks, shock metamorphism, and structural features in the Rubielos de la Cérida structure, Spain: evidence for a companion to the Azuara impact structure, in: Impact markers in the stratigraphic record, 6th ESF-IMPACT workshop Granada, abstract book: 23-24.
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In the image of a brick splashing into water to the right, one can identify freely moving airborne water droplets, a phenomenon typical of high Reynolds number flows; the intricate non-spherical shapes of the droplets show that the Weber number is high. Also seen are entrained air bubbles in the body of the water, and an expanding ring of disturbance propagating away from the impact site. Small scale splashes in which a droplet of liquid hits a free surface can produce symmetric forms that resemble a coronet; milk is often used as it is opaque. Sand is said to splash if hit sufficiently hard (see dry quicksand) and sometimes the impact of a meteorite is referred to as splashing, if small bits of ejecta are formed.
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It has been estimated that the crater is about across. The impact would have created a blast with the force of 145,000 megatons and that the shock wave would have created winds of as far away as the site of modern Aberdeen. In order to reduce the uncertainty in the location of the impact, the main exposures of the Stac Fada Member have been re-examined to look for evidence of the direction that the ejecta from the impact was moving as it was deposited. The orientation of small-scale thrust faults and folds and striae found locally at the base of the unit have been combined with measurements of the fabric in the rocks using anisotropy of magnetic susceptibility.
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ACE also measures abundances of cosmic ray nickel-59 and cobalt-59 isotopes; these measurements indicate that a time longer than the half-life of nickel-59 with bound electrons (7.6 × 104 years) elapsed between the time nickel-59 was created in a supernova explosion and the time cosmic rays were accelerated. Such long delays indicate that cosmic rays come from the acceleration of old stellar or interstellar material rather than from fresh supernova ejecta. ACE also measures an iron-58/iron-56 ratio that is enriched over the same ratio in solar system material. These and other findings have led to a theory of the origin of cosmic rays in galactic superbubbles, formed in regions where many supernovae explode within a few million years.
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Nearby volcanic vents include the Sisi Butte, South Pinhead, and West Pinhead shield volcanoes and the Fort Butte, North Pinhead, and Potato Butte cinder cones. Cinder cones in the area have gray-red cinders that have been oxidized, scoria, agglomerate, and small lava flows consisting of porphyritic basaltic andesite and black and yellow-brown to dark yellow-orange, palagonite basaltic andesite. The black and orange color of some of the eruptive material from these cones suggests that there was interaction of the lava with wet ground or snow, causing rapid chilling of the ejecta that prevented oxidation from taking place. At Double Peaks and an unnamed hill southwest of View Lake, there are gray-pink to light brown-gray hornblende dacite lava domes.
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The Caloris Montes Formation, which was informally called the Caloris mountains terrain by Trask and Guest, consists of a jumbled array of smooth-appearing but highly segmented mountain massifs that rise 1-2 km above the surrounding terrain. These massifs mark the crestline of the most prominent scarp or ring of the Caloris Basin and grade outward into smaller blocks and lineated terrain. The Caloris Montes Formation is very similar in morphology to and is considered the equivalent of the massif facies of the Montes Rook Formation around the Orientale Basin. The Caloris Montes is interpreted as basin rim deposits consisting of ejecta from deep within Caloris that is mixed with but generally overlies uplifted and highly fractured prebasin bedrock.
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This phenomenon, which results in a reduced dispersion of ejecta and secondary craters, is best observed within the Borealis region around craters Verdi and Depréz. Slight differences between mercurian and lunar crater morphologies are unrelated to differences in the Mercurian and lunar gravitational fields (Cintala and others, 1977; Malin and Dzurisin, 1977, 1978;). Instead, the morphologic components of crater interiors and the abundance of central peaks and terraces on both bodies seem to be related to the physical properties of the target material (Cintala and others, 1977; Smith and Hartnell, 1978). The clusters of closely packed and overlapping large craters west of crater Gauguin and east of crater Mansart, together with nearby isolated craters and surrounding material, were mapped by Trask and Guest as heavily cratered terrain.
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In Borealis Planitia, however, most of the ridges are of external origin. They appear either to outline the rim crests of subjacent ghost craters that are lightly mantled by smooth plains material or to be lava flow fronts. The map shows the rim crests of 20 ghost craters, ranging in diameter from 40 to 160 km, that are buried under the smooth plains material of Borealis Planitia, which material is coextensive with the fill covering the floor of the Goethe Basin. In addition, ejecta from the crater Depréz extend more than 40 km eastward beyond a circular scarp that may represent the rim crest of a buried crater 170 km in diameter (FDS 156, 160) or, more likely, the front of lava flows.
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In 1993, Bohdan Paczyński and James E. Rhoads published an article arguing that, regardless of the type of explosion that causes GRBs, the extreme energetics of GRBs meant that matter from the host body must be ejected at relativistic speeds during the explosion. They predicted that the interaction between the ejecta and interstellar matter would create a shock front. Should this shock front occur in a magnetic field, accelerated electrons in it would emit long- lasting synchrotron radiation in the radio frequencies, a phenomenon that would later be referred to as a radio afterglow.Paczyński 1993 Jonathan Katz later concluded that this lower-energy emission would not be limited to radio waves, but should range in frequency from radio waves to x-rays, including visible light.
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2014 saw the return of many of the initiatives from 2013 but added upon them. The lineup expanded to 8 features along with 15 shorts, and included the first educational Industry Panel from the festival, furthering its commitment to the genre community. In a first for the festival, multiple second screenings (running concurrently to the original schedule on a 2nd screen) had to be added due to ticket demand. Continuing at the Carlton in its third year on November 28 to 30, 2014, the festival screened the world premieres of Teddy Bomb and Heinous Acts along with Canadian and Toronto premieres of Berkshire County, Queen of Blood (starring Skinny Puppy's Nivek Ogre), Ejecta, Bloody Knuckles, Black Mountain Side and Kingdom Come.
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Radiocarbon dating has established that Mount Tambora had erupted three times during the current Holocene epoch before the 1815 eruption, but the magnitudes of these eruptions are unknown. Their estimated dates are 3910 BC ± 200 years, 3050 BC and 740 AD ± 150 years. An earlier caldera was filled with lava flows starting from 43,000 years BP; two pyroclastic eruptions occurred later and formed the Black Sands and Brown Tuff formations, the last of which was emplaced between about 3890 BC and 800 AD. In 1812, Mount Tambora became highly active, with its maximum eruptive intensity occurring in April 1815. The magnitude was 7 on the Volcanic Explosivity Index (VEI) scale, with a total tephra ejecta volume of up to 1.8 × 1011 cubic metres.
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The volcano has a caldera at its summit, which has a diameter of and features two crater lakes: Paulina Lake and East Lake. This caldera, known as the Newberry Crater, is forested, with small parts of its surface covered with lava flows and pumice deposits. Before the caldera's creation, the mountain's summit was greater in height than its current elevation. The caldera has reformed several times throughout the volcano's history, burying the caldera floor to a depth of and creating concentric calderas, each smaller than its predecessor. The first caldera—the volcano's largest caldera, forming approximately 300,000 years ago—was produced by the eruption of of pyroclastic ejecta, which created the Tepee Draw tuff and ash deposits that cover the volcano's eastern flank.
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The northern rim in particular has been nearly obliterated by overlapping impacts, and the southern rim is not in much better shape with a stretch overlain by Backlund. The southeast rim of Pasteur is nearly linear near where the ground has been modified by Hilbert. Even the western rim is heavily damaged, with overlying craters Pasteur U, Anders' Earthrise crater, and Pasteur Q. (The first of these, Pasteur U, forms a merged group of overlapping craters.) The interior is not in much better shape, with the southern half irregular from ejecta covering the surface, and several small craters lying across the floor. In the northwest part of the floor is a short chain of small, overlapping craters forming an arcing line from north to south.
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In either case, the resulting supernova explosion expels much or all of the stellar material with velocities as much as 10% the speed of light (or approximately 30,000 km/s). These speeds are highly supersonic, so a strong shock wave forms ahead of the ejecta. That heats the upstream plasma up to temperatures well above millions of K. The shock continuously slows down over time as it sweeps up the ambient medium, but it can expand over hundreds or thousands of years and over tens of parsecs before its speed falls below the local sound speed. One of the best observed young supernova remnants was formed by SN 1987A, a supernova in the Large Magellanic Cloud that was observed in February 1987.
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By the 16th century BC pottery and other remains on the Greek mainland show that the Minoans had far-reaching contacts on the mainland. In the 16th century a major earthquake caused destruction on Crete and on Thera that was swiftly repaired. By about the 15th century BC a massive volcanic explosion known as the Minoan eruption blew the island of Thera apart, casting more than four times the amount of ejecta as the explosion of Krakatoa and generating a tsunami in the enclosed Aegean that threw pumice up to 250 meters above sea level onto the slopes of Anaphi, 27 km to the east. Any fleet along the north shore of Crete was destroyed and John Chadwick suggests that the majority of Cretan fleets had kept the island secure from the Greek-speaking mainlanders.
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While the cataclysm hypothesis has recently gained in popularity, particularly among dynamicists who have identified possible causes for such a phenomenon, the cataclysm hypothesis is still controversial and based on debatable assumptions. Two criticisms are that (1) the "cluster" of impact ages could be an artifact of sampling a single basin's ejecta, and (2) that the lack of impact melt rocks older than about 4.1 Ga is related to all such samples having been pulverized, or their ages being reset. The first criticism concerns the origin of the impact melt rocks that were sampled at the Apollo landing sites. While these impact melts have been commonly attributed to having been derived from the closest basin, it has been argued that a large portion of these might instead be derived from the Imbrium basin.
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The Chicxulub impactor produced the Chicxulub crater and subsequent carbonate-debris breccia, which became the oil reservoir for the fields around Villahermosa and the Bay of Campeche where the Cantarell Complex is located.Barton, R., Bird, K., Hernandez, J.G., Grajales-Nishimura, J.M., Murillo-Muneton, G., Herber, B., Weimer, P., Koeberl, C., Neumaier, M., Schenk, O., Stark, J., 2010, High Impact Reservoirs, Oilfield Review, Houston: Schlumberger, pp. 14-29 The porosity is 8%-12% in the reservoir at a depth of about 1500 m, which grades from being coarse-grained to fine-grained, called Unit 1 and 2 respectively, and overlain by a seal of shaly ejecta-rich layer called Unit 3. Following impact, the carbonate platform collapsed, depositing the coarse breccias, which were then overlain mixed and overlain by finer breccias from the consequent tsunamis.
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The similarity of its orbit with Earth was also very difficult to explain from natural sources, with ejecta from a recent Lunar impact or non-gravitational perturbations such as the Yarkovsky effect having been suggested. The first Earth Trojan asteroid, , was later identified and such objects could well be a source for objects like 1991 VG. 1991 VG has been a transient co-orbital of the horseshoe type in the past and it will return as such in the future; it was a natural satellite of Earth for about a month since 1992. This temporary capture may have taken place multiple times in the past and it is expected to repeat again in the future. It had an eccentricity of less than 1 with respect to the Earth from 23 February to 21 March 1992.
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Frese, R. von, Potts, L., Wells, S., Leftwich, T., Kim, H., et al., 2009, "GRACE gravity evidence for an impact basin in Wilkes Land, Antarctica," in Geochemistry, Geophysics, and Geosystems, v. 10. However, there are already other suggested candidates for giant impacts at the Permian–Triassic boundary, such as Bedout, off the northern coast of Western Australia, although all are equally contentious and it is currently under debate whether or not an impact played any role in this extinction. The complete absence of a well-defined impact ejecta layer associated with the Permian–Triassic boundary at its outcrops within Victoria Land and the central Transantarctic Mountains argues against there having been any impact capable of creating a crater the size of the hypothesized Wilkes Land impact crater within Antarctica at the Permian–Triassic boundary.
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The fluid flow theories propose fluid action which would erode the surrounding area and produce the channels that separate Abalos Mensa from the main ice cap. The fluid flow theories require volcanic action which would provide the thermal energy to melt the polar materials which would then flow and cause erosion of the area. There have been a number of questions raised about the fluid flow theories, including the uncertainty of volcanic activity in the Planum Boreum region. Impact-shielding-based Aeolian theories propose that ancient material from the base of Planum Boreum was protected by ejecta from an impact crater, and when the old base material of the surrounding area disappeared, the protected mound acted like a source for further accumulation of new deposits, which, with time, produced the mound of Abalos Mensa.
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The crater has a symmetrical bowl-shaped topography and is considered to be one of the best preserved small meteorite craters on Earth. Abstract The wide rim rises about above the plain, while the deepest point of the central depression is below the rim crest; the rim to rim diameter averages about . Based on cosmogenic nuclide exposure dating of the crater walls, the crater is less than 20 thousand years old, while the pristine state of preservation of the ejecta has been used to suggest that it may in fact be less than 4 thousand years old. The iron meteorite fragments collected around the crater are classified as a coarse octahedrite belonging to chemical class IIAB; the fragments show considerable evidence of deformation presumably related to the impact explosion.
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Type Iax supernova, that involve helium accretion by a white dwarf, have been proposed to be a channel for transformation of this type of stellar remnant. In this scenario, the carbon detonation produced in a Type Ia supernova is too weak to destroy the white dwarf, expelling just a small part of its mass as ejecta, but produces an asymmetric explosion that kicks the star, often known as a zombie star, to high speeds of a hypervelocity star. The matter processed in the failed detonation is re-accreted by the white dwarf with the heaviest elements such as iron falling to its core where it accumulates. These iron- core white dwarfs would be smaller than the carbon–oxygen kind of similar mass and would cool and crystallize faster than those.
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More precise radiometric dating by Hodych & Dunning (1992) has shown that the Manicouagan impact occurred about 214 million years ago, about 13 million years before the Triassic–Jurassic boundary. Therefore, it could not have been responsible for an extinction precisely at the Triassic–Jurassic boundary. Nevertheless, the Manicouagan impact did have a widespread effect on the planet; a 214-million-year-old ejecta blanket of shocked quartz has been found in rock layers as far away as England and Japan. There is still a possibility that the Manicouagan impact was responsible for a small extinction midway through the late Triassic at the Carnian–Norian boundary, although the disputed age of this boundary (and whether an extinction actually occurred in the first place) makes it difficult to correlate the impact with extinction.
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Also, the lake's long axis points to the hypocenter of the Tunguska explosion, about 7.0 km away. Magnetic readings also indicate a possible meter-sized chunk of rock below the lake's deepest point, which may be a fragment of the colliding body. In 2008, a BBC News story on the 100th anniversary of the Tunguska Event mentioned that researchers at Imperial College London had pointed out that many of the trees surrounding the lake are older than 100 years, which suggests that the lake could not have been created by an impact in 1908. The researchers also pointed out other problems, including the morphology of the lake and the surrounding terrain, the lack of impactor debris and ejecta, noting that the characteristics of the impactor required by the impact theory are inconsistent with existing models of the known features of the event.
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Basalts are sparse in samples of Cone crater ejecta, but somewhat abundant in samples recovered farther west, on the opposite side of the immediate landing site. Two explanations have been presented for this: (1) the majority of basalt in the landing site lies below the depth of excavation of Cone crater or (2) the presence of a basalt flow beneath the landing area excavated by a nearby crater with a diameter of . It is believed that the former seems more likely, as the basalts are similar to the basalts recovered at Cone crater. It is inconclusive whether or not the recovered basalts have a direct affiliation with the landing site, as it is located in a valley between ridges, and there exists the possibility that the basalts were merely deposited there as a result of other impact events.
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An early naval cannon, which is allowed to roll backwards slightly when fired, and therefore must be tethered with strong ropes. Recoil (often called knockback, kickback or simply kick) is the rearward thrust generated when a gun is being discharged. In technical terms, the recoil is a result of conservation of momentum, as according to Newton's third law the force required to accelerate something will evoke an equal but opposite reactional force, which means the forward momentum gained by the projectile and exhaust gases (ejecta) will be mathematically balanced out by an equal and opposite momentum exerted back upon the gun. In hand-held small arms, the recoil momentum will be eventually transferred to the ground, but will do so through the body of the shooter hence resulting in a noticeable impulse commonly referred to as a "kick".
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During firing, the bullet flies through the bore with little hindrance, but most of the expanding gas ejecta behind it is retained through a longer and convoluted escape path created by the baffles, prolonging the release time. This slows down the gas and dissipating its kinetic energy into a larger surface area, reducing the blast intensity, and thus lowering the loudness. Silencers can also reduce the recoil during shooting, but unlike a muzzle brake or a recoil compensator, which reduce recoil by vectoring more of the blast impulse laterally (hence actually making the noise louder for bystanders), silencers release almost all the gases towards the front. However, the internal baffles significantly prolong the time of the gas release and therefore decrease the rearward thrust generated — as for the same impulse, force is inversely proportional to time.
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The August 4 flare and ejecta caused significant to extreme effects on the Earth's magnetosphere, which responded in an unusually complex manner. The disturbance storm time index (Dst) was only -125 nT, falling merely within the relatively common "intense" storm category. Initially an exceptional geomagnetic response occurred and some extreme storming occurred locally later (some of these possibly within substorms), but arrival of subsequent CMEs with northward oriented magnetic fields is thought to have shifted the interplanetary magnetic field (IMF) from an initial southward to northward orientation, thus substantially suppressing geomagnetic activity as the solar blast was largely deflected away from rather toward Earth. An early study found an extraordinary asymmetry range of ≈450 nT. A 2006 study found that if a favorable IMF southward orientation were present that the Dst may have surpassed 1,600 nT, comparable to the 1859 Carrington event.
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No material similar to either the lineated or the secondary-crater facies of the Van Eyck Formation, the most distinctive and distant unit of the Caloris Group (McCauley and others, 1981), can be unambiguously identified in the Borealis region. A few rounded hills or knobs, too small to be mapped, are present; they are morphologically similar to blocks of the Odin Formation surrounding the Caloris Basin in the Shakespeare quadrangle (Guest and Greeley, 1983), and to features of the Alpes Formation around the Imbrium Basin on the Moon. Two of the most striking of these knobs are possibly long and across; they rise above smooth plains material that fills a much degraded, unmapped, irregular crater at 69° N., 157° W. (FDS 088). These knobs are about northeast of Caloris Montes and may represent Caloris Basin ejecta.
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Alamo bolide impact breccia (Late Devonian, Frasnian) near Hancock Summit, Pahranagat Range, Nevada Impact breccias are thought to be diagnostic of an impact event such as an asteroid or comet striking the Earth and are normally found at impact craters. Impact breccia, a type of impactite, forms during the process of impact cratering when large meteorites or comets impact with the Earth or other rocky planets or asteroids. Breccia of this type may be present on or beneath the floor of the crater, in the rim, or in the ejecta expelled beyond the crater. Impact breccia may be identified by its occurrence in or around a known impact crater, and/or an association with other products of impact cratering such as shatter cones, impact glass, shocked minerals, and chemical and isotopic evidence of contamination with extraterrestrial material (e.g.
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In 2017, entirely new astronomical data about the r-process was discovered in data about the merger of two neutron stars. Using the gravitational wave data captured in GW170817 to identify the location of the merger, several teams observed and studied optical data of the merger, finding spectroscopic evidence of r-process material thrown off by the merging neutron stars. The bulk of this material seems to consist of two types: hot blue masses of highly radioactive r-process matter of lower-mass- range heavy nuclei ( such as strontium) and cooler red masses of higher mass- number r-process nuclei () rich in actinides (such as uranium, thorium, and californium). When released from the huge internal pressure of the neutron star, these ejecta expand and form seed heavy nuclei that rapidly capture free neutrons, and radiate detected optical light for about a week.
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Months after the explosion, when the outer layers have expanded to the point of transparency, the spectrum is dominated by light emitted by material near the core of the star, heavy elements synthesized during the explosion; most prominently isotopes close to the mass of iron (iron-peak elements). The radioactive decay of nickel-56 through cobalt-56 to iron-56 produces high-energy photons, which dominate the energy output of the ejecta at intermediate to late times. The use of Type Ia supernovae to measure precise distances was pioneered by a collaboration of Chilean and US astronomers, the Calán/Tololo Supernova Survey. In a series of papers in the 1990s the survey showed that while Type Ia supernovae do not all reach the same peak luminosity, a single parameter measured from the light curve can be used to correct unreddened Type Ia supernovae to standard candle values.
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The opener "Wasat" sets the scene of the story, starting with a short, atmospheric prelude before it moves into "an uptempo, hypercolor groove". The "VHS-quality dubstep" track "Mind" is where the record gets suspenseful, as the drums "threaten" to become, but doesn't entirely become, a fully developed hard-hitting four-on-the-floor beat. These two tracks were described by a Spectrum Culture critic as "a practice in coalescence; taking a moment to take shape and then defying one another’s difference until they too find their peaceful plane of existence." The most melodic track on the EP, "Declination", as well as probably the "most straightforwardly melodic" cut in Com Truise's discography as of the release of the EP, "glides into your headphones like a starship slipping down out of hyperspace", featuring vocals of Joel Ford from the projects Ford & Lopatin, Airbird and Young Ejecta.
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The arrival time of the associated coronal mass ejection (CME) and its coronal cloud, 14.6 hours, remains the record shortest duration as of November 2018, indicating an exceptionally fast and typically geoeffective event (normal transit time is two to three days). A preceding series of solar flares and CMEs cleared the interplanetary medium of particles, enabling the rapid arrival in a process similar to the solar storm of 2012. Normalizing the transit times of other known extreme events to a standard 1 AU to account for the varying distance of the Earth from the Sun throughout the year, one study found the ultrafast August 4 flare to be an outlier to all other events, even compared to the great solar storm of 1859, the overall most extreme known solar storm which is also known as the "Carrington event". This corresponds to an ejecta speed of an estimated .
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In the science of tephrochronology, the Saksunarvatn tephra is volcanic ejecta that formed an ash layer that is useful in dating Northern European sediment layers that were laid down during the Boreal period, the warm climate phase that followed the cold snap of the Younger Dryas as the earth made the transition from the last Pleistocene glaciation to the current interglacial, or Holocene. This was a period of rapid climatic transitions around the North Atlantic, some of which took place during a matter of decades. Similar effects are evident in independent palaeoclimatic reconstructions obtained from pollen zones, marine and ice-core records, but these sequences cannot be reliably calibrated with one another. The ash layer from a specific volcanic event, deposited simultaneously over wide areas, provides a common reference point or time marker called a horizon, which establishes simultaneity in the sequences wherever that layer is found: this set of techniques is called tephrochronology.
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The Imbrium impact basin is the youngest and largest of the multi-ring basins found on the central nearside of the Moon, and quantitative modeling shows that significant amounts of ejecta from this event should be present at all of the Apollo landing sites. According to this alternative hypothesis, the cluster of impact melt ages near 3.9 Ga simply reflects material being collected from a single impact event, Imbrium, and not several. Additional criticism also argues that the age spike at 3.9 Ga identified in 40Ar/39Ar dating could also be produced by an episodic early crust formation followed by partial 40Ar losses as the impact rate declined. A second criticism concerns the significance of the lack of impact melt rocks older than about 4.1 Ga. One hypothesis for this observation that does not involve a cataclysm is that old melt rocks did exist, but that their radiometric ages have all been reset by the continuous effects of impact cratering over the past 4 billion years.
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At least eleven prehistoric tsunamis have struck the Indian Ocean coast of Indonesia between 7400 and 2900 years ago. Analysing sand beds in caves in the Aceh region, scientists concluded that the intervals between these tsunamis have varied from series of minor tsunamis over a century to dormant periods of more than 2000 years preceding megathrusts in the Sunda Trench. Although the risk for future tsunamis is high, a major megathrust such as the one in 2004 is likely to be followed by a long dormant period. A group of scientists have argued that two large-scale impact events have occurred in the Indian Ocean: the Burckle Crater in the southern Indian Ocean in 2800 BCE and the Kanmare and Tabban craters in the Gulf of Carpentaria in northern Australia in 536 CE. Evidences for these impacts, the team argue, are micro-ejecta and Chevron dunes in southern Madagascar and in the Australian gulf.
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Hollywood and video game depictions of firearm shooting victims being thrown several feet backwards are inaccurate, although not for the often-cited reason of conservation of energy, which would also be in error because conservation of momentum would apply. Although energy (and momentum) must be conserved (in a closed system), this does not mean that the kinetic energy or momentum of the bullet must be fully deposited into the target in a manner that causes it to fly dramatically away. For example, a bullet fired from an M16 rifle has approximately 1763 joules of kinetic energy as it leaves the muzzle, but the recoil energy of the gun is less than 7 joules. Despite this imbalance, energy is still conserved because the total energy in the system before firing (the chemical energy stored in the propellant) is equal to the total energy after firing (the kinetic energy of the recoiling firearm, plus the kinetic energy of the bullet and other ejecta, plus the heat energy from the explosion).
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Moon rocks contain more heavy isotopes of zinc, and overall less zinc, than corresponding igneous Earth or Mars rocks, which is consistent with zinc being depleted from the Moon through evaporation, as expected for the giant impact origin. Collisions between ejecta escaping Earth's gravity and asteroids would have left impact heating signatures in stony meteorites; analysis based on assuming the existence of this effect has been used to date the impact event to 4.47 billion years ago, in agreement with the date obtained by other means. Warm silica-rich dust and abundant SiO gas, products of high velocity (> 10 km/s) impacts between rocky bodies, have been detected by the Spitzer Space Telescope around the nearby (29 pc distant) young (~12 My old) star HD172555 in the Beta Pictoris moving group. A belt of warm dust in a zone between 0.25AU and 2AU from the young star HD 23514 in the Pleiades cluster appears similar to the predicted results of Theia's collision with the embryonic Earth, and has been interpreted as the result of planet-sized objects colliding with each other.
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The southeast half of the quadrangle is dominated by ancient crater deposits, by nondescript rolling to hummocky plains materials between individual craters, and by isolated patches of nondescript plains. The ancient and degraded Tolstoj multiring basin, about 350 km in diameter, is in the south-central part of the quadrangle. The large, well-preserved crater Mozart (285 km diameter) is a prominent feature in the western part of the area; its extensive ejecta blanket and secondary crater field are superposed on the smooth plains surrounding Caloris. Low-albedo features Solitudo Neptunii and Solitudo Helii, adopted from telescopic mapping, appear to be associated with the smooth plains material surrounding Caloris; a third low-albedo feature, Solitudo Maiae, appears to be associated with the Tolstoj Basin.For location of albedo features see Mercury’s rotation period of 58.64 days is in two-thirds resonance with its orbital period of 87.97 days Therefore, at its equator, longitudes 0° and 180° are subsolar points (“hot poles”) near alternate perihelion passage. The “hot pole” at 180° lies within the Tolstoj quadrangle; at perihelion, equatorial temperatures range from about 100 K at local midnight to 700 K at local noon.
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525 and Melosh, who had initially supported the hypothesis, with this re-evaluation being dubbed the "Cretaceous-Palaeogene firestorm debate" by Belcher.Depending on the size of the meteor, it will either burn up high in the atmosphere or reach lower levels and explode in an air burst akin to the Chelyabinsk meteor of 2013, which approximated the thermal effects of a nuclear explosion. The issues raised by these scientists in the debate are the perceived low quantity of soot in the sediment beside the fine-grained iridium-rich asteroid dust layer, if the quantity of re-entering ejecta was perfectly global in blanketing the atmosphere, and if so, the duration and profile of the re-entry heating, whether it was a high thermal pulse of heat or the more prolonged and therefore more incendiary "oven" heating, and finally, how much the "self- shielding effect" from the first wave of now-cooled meteors in dark flight contributed to diminishing the total heat experienced on the ground from later waves of meteors. In part due to the Cretaceous period being a high- atmospheric-oxygen era, with concentrations above that of the present day.
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Clayton introduced the idea that the relative abundances of the isotopes in tiny solid dust grains that condensed within hot gas leaving individual stars would be observable in such single dust grains. Those grains reveal the isotopic composition of their parent stars. He named these solids stardust,Precondensed Matter: Key to the Early Solar System, Moon & Planets 19, 109 (1978) postulating thereby a new component of interstellar Cosmic dust. Stardust inherits its unusual isotopic compositions from the evolved nuclear composition of the parent star within which that grain condensed. Clayton's initial steps[ “Extinct radioactivities: Trapped residuals of pre-solar grains”, Astrophys. J., 199, 765-69, (1975); “22Na, Ne-E, Extinct radioactive anomalies and unsupported 40Ar”, Nature, 257, 36-37, (1975) focused on large isotopic excesses in supernova dust grains owing to decays of abundant short-lived radioactive nuclei that were created in the nuclear explosion and then condensed within a few months in the cooling ejecta; but it was generalized to all types of stellar mass loss in 1978.Donald D. Clayton, Precondensed Matter: Key to the Early Solar System, Moon & Planets 19, 109 (1978); "Grains of anomalous isotopic composition from novae", Clayton & Hoyle, Astrophys.J. 203, 490 (1976); “Cosmoradiogenic ghosts and the origin of Ca-Al-rich inclusions”, Earth and Planetary Sci. Lett.
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Impact feature: Shock-melted glass from the Rubielos de la Cérida impact structure under the scanning electron microscope. The c. 80 km x 40 km sized Rubielos de la Cérida impact structure (impact basin, resp.) is located in Aragon, northeast Spain, north of Teruel and is consideredErnstson, K., Anguita, F., and Claudin, F. 1994. Shock cratering of conglomeratic quartzite pebbles and the search and identification of an Azuara (Spain) probable companion impact structure, in: Shock wave behavior of solids in nature and experiments, 3rd ESF-Impact Workshop Limoges, abstract book: 25.. Hradil, K., Schüssler, U., and Ernstson, K. 2001. Silicate, phosphate and carbonate melts as indicators for an impact-related high-temperature influence on sedimentary rocks of the Rubielos de la Cérida structure, Spain, in: Impact markers in the stratigraphic record, 6th ESF-IMPACT workshop Granada, abstract book: 49-50. Claudin, F., Ernstson, K., Rampino, M.R., and Anguita, F. 2001. Striae, polish, imprints, rotated fractures, and related features from clasts in the Puerto Mínguez impact ejecta, in: Impact markers in the stratigraphic record, 6th ESF-IMPACT workshop Granada, abstract book: 15-16. Ernstson, K., Claudin, F., Schüssler, U. & Hradil, K. (2002): The mid-Tertiary Azuara and Rubielos de la Cérida paired impact structures (Spain).
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