144 Sentences With "determine the age of" | Random Sentence Generator

Knowing that weight also allowed scientists to determine the age of the rings.

To determine the age of cave paintings, for example, researchers have traditionally relied on radiocarbon dating.

The astronomers can determine the age of the star, as well as its mass and radius.

They used multi-waveband images from a large-diameter telescope to determine the age of its features.

To determine the age of the tools, the researchers took advantage of the planet's changing magnetic field.

The test can determine the age of whiskies distilled after 63 to within a 1-3 year period.

Indeed, forensic scientists are often tasked with having to determine the age of corpses in various states of decay.

One of the coolest (OK, maybe the coolest) is using radioactive carbon to determine the age of old bones or plants.

Researchers used the rock layers to determine the age of the fossils, suggesting that they're no older than 1.4 million years old.

To determine the age of Greenland sharks, Nielsen and his colleagues examined the eye lens nuclei of 28 females, caught during scientific surveys.

How they did it: Silicon crystals contain radioactive uranium and thorium whose decay can be used to determine the age of the crystals.

For years, scientists have been refining techniques to determine the age of a painting using radiocarbon dating and the lingering effects of the tests.

An international team of geologists, paleobotanists and paleoanthropologists helped to determine the age of the skull by studying the habitat where it was found.

Based on the stars' properties, the team was able to determine the age of the cluster and that it once passed by our solar neighborhood.

A few years later, another scientist, Willard Libby, figured out how to use the isotope to determine the age of fossils and other natural artifacts.

The asphalt seeps preserve fossils so well that scientists can extract molecular data and determine the age of the specimens as well as when they died.

They knew when each one was distilled, so they were able to use that data to create a calibration curve to determine the age of Scotch.

SUERC's researchers used "advanced radiocarbon dating techniques" to determine the age of the Scotch in each bottle and, boy howdy, they had to be surprised by the results.

As a result, scientists can determine the age of dead organic matter up to tens of thousands of years old by calculating the ratio of those carbon isotopes.

Upcoming measurements will determine the age of the mammoth when it died, which could clarify whether it's a Columbian, a pygmy, or some kind of transitional or intermediary species.

It has helped determine the age of the universe, the expansion rate of the universe, the mass and size of our home Milky Way galaxy, among many other major discoveries.

They're prized for their beauty as well as their value to science, since they serve as good reference tools to determine the age of the rock they were found in.

Scientists at the University of Leeds and the British Antarctic Survey on Seymour Island in the Antarctic Peninsula recently completed testing to determine the age of more than 6,000 marine fossils.

Japan says the point of examining the carcasses is to determine the age of dead whales so as to increase awareness of what is needed to help preserve "sustainable" whale numbers.

Natalia was born with a rare form of dwarfism called spondyloepiphyseal, which makes it difficult to obtain an accurate bone scan — a procedure typically used to determine the age of someone.

Calls have multiplied for mandatory medical exams to determine the age of migrants claiming to be minors and for swifter deportations of those who — like the suspect — have been denied asylum.

The presumably predictable cooling process of white dwarfs meant that astronomers could measure their temperature and use them as a sort of cosmic clock to determine the age of other nearby celestial objects.

To determine the age of the star, a research team from the Rochester Institute of Technology and the University of California, Los Angeles measured its X-ray output using the XMM-Newton space observatory.

Developed in the 1940s, radiocarbon dating allows scientists to determine the age of a wide range of materials — including fossils, cave paintings, parchment and even human remains — by examining the types of carbon atoms they contain.

The researchers were hoping to study how various scavengers disrupt human remains, and to record the unique signatures left by each animal; armed with this sort of data, scientists can better determine the age of human remains.

Police would try to determine the age of the cow carcass, police official Anand Kumar said when asked if there had been a conspiracy to vitiate the atmosphere by using a dead cow brought in from elsewhere.

Scientists on Thursday said they used a technique called radiocarbon dating to determine the age of artifacts unearthed at an archeological site called Cooper's Ferry along the Salmon River in western Idaho near the town of Cottonwood.

Then he snips a piece of jawbone and counts the layers like tree rings to determine the age of the fish — something he has done with every paddlefish caught in the caviar programs in the three states.

The Sun newspaper, incensed about being called racist for demanding dental X-rays to determine the age of the child refugees, ran a front-page article accusing Mr. Lineker of "peddling" a lie and demanded that the taxpayer-funded BBC fire him.

Because the works were rarely dated, researchers did some sleuthing to determine the age of the paintings: exploring when particular flag designs were introduced, various buildings were finished or burned down, and different types of ships and specific vessels embarked or ended up wrecked.

In addition, even if the authors used the oldest radiocarbon date to determine the age of the site, that would put humans in North America by 15,300 years ago, which precludes that the initial migration to the Americas took place through the ice-free corridor.

For example, geologists would love to send an ion microprobe that can measure elemental abundances at the scale of millionths of a meter; the abundances of particular isotopes can then be used to determine the age of a specific bit of rock in a sample.

Lichenometry is a technique used to determine the age of exposed rock surfaces based on the size of lichen thalli. Introduced by Beschel in the 1950s, the technique has found many applications. it is used in archaeology, palaeontology, and geomorphology. It uses the presumed regular but slow rate of lichen growth to determine the age of exposed rock.

The dating of igneous rocks determines when magma solidified into rock. Radiogenic isotopes are frequently used to determine the age of igneous rocks.

CLSM is used as the data retrieval mechanism in some 3D optical data storage systems and has helped determine the age of the Magdalen papyrus.

M. maorum had been used as a model to determine the age of merobenthic, by using stylet increment analysis. SIA is a method which was developed recently to determine the age of an octopus, age is important for estimating the growth rate, population age structure, mortality rate, productivity and processes. Due to this understanding, it can be used to make important decisions surrounding fisheries and conservation management. Stylets are highly reduced internal shells that consist of a small rod- like structures, the result of SIA of showed that a stylet of M. maorum can be hard to prepare and age.

40Ar, the most abundant isotope of argon, is produced by the decay of 40K with a half-life of 1.25 years by electron capture or positron emission. Because of this, it is used in potassium–argon dating to determine the age of rocks.

Iran uses the lunar Islamic calendar to determine the age of criminal responsibility, which is shorter than the standard solar calendar, so as a result some people sentenced to death at the age of 18 would be 17 years old in solar calendar years.

Modern science indicates various ways in which genetics, diet, and lifestyle affect human longevity. It also allows us to determine the age of human remains with a fair degree of precision. The Sacrifice of Noah, Jacopo Bassano (c. 1515–1592), Potsdam-Sanssouci, c. 1574.

While not entirely independent of the properties of the stars in the cluster, system, or other reasonably-sized association of stars, an astronomer would only need a representative sample of stars to determine the age of the cluster, rather than painstakingly finding the age of every star in the cluster through other properties. In addition, knowing the age of one member of a star system can help determine the age of that system. In a star system, stars almost always form at the same time as each other, and given the age of one star, the age of all of the others can be known. However, this method does not work for galaxies.

Often, when a volcano explodes, biological organisms are killed and their remains are buried within the tephra layer. These fossils are later dated by scientists to determine the age of the fossil and its place within the fossil record. A 2007 eruptive plume at Mount Etna produced volcanic ash, pumice, and lava bombs.

A graph showing the hypothesized growth curves (body mass versus age) of four tyrannosaurids. Daspletosaurus is shown in green, based on Erickson et al., 2004 Paleontologist Gregory Erickson and colleagues have studied the growth and life history of tyrannosaurids. Analysis of bone histology can determine the age of a specimen when it died.

A graph showing the hypothesized growth curves (body mass versus age) of four tyrannosaurids. Gorgosaurus is shown in blue. Based on Erickson et al. 2004. Gregory Erickson and colleagues have studied the growth and life history of tyrannosaurids using bone histology, which can determine the age of a specimen when it died.

It is also used as a tracer for water transport studies in life-science research. Furthermore, since it naturally occurs in minute quantities, it can be used to determine the age of various water-based liquids, such as vintage wines. The name super-heavy water helps distinguish the tritiated material from heavy water, which contains deuterium instead.

A 2009 study to determine the age of the CORA tree was inconclusive. Damage to the tree, caused by lightning and decay, has made it impossible to obtain a valid core sample for tree-ring dating. Even if the tree dates back to the 16th century, though, establishing the age of the inscription would be another matter.

A graph showing the hypothesized growth curves (body mass versus age) of four tyrannosaurids. Gorgosaurus is shown in blue and Albertosaurus is shown as red. Based on Erickson et al. 2004. Gregory Erickson and colleagues have studied the growth and life history of tyrannosaurids using bone histology, which can determine the age of a specimen when it died.

People who use wells in the desert could be warned that one day they would lack water. When the differences changed, that meant that there was new water, so people could use the water without worries. This technique can be used to determine the age of nitrogen in plankton, as well. Yaya Diallo was enthusiastic to work on the project.

The rock has a porphyritic texture with large crystals of orthopyroxene and phlogopite set in a fine grained matrix. The phlogopite crystals have been used to determine the age of the dike and its crystallization temperature (900 °C (1,650 °F)). The dike also contains fragments of other rock types. These xenoliths include pieces of limestone, clastic sedimentary rocks, and gneiss.

Petterson's first publication from 1910 was on the issue of radium. In 1913 he joined the staff of the Swedish Hydrographic-Biologocal Commission. In 1914 he began lecturing in Oceanography at Gothenburg University. He later brought this knowledge to the field of oceanography, and with the help of radium he could determine the age of sediment samples from the bottom of the sea.

Gyro- chronology is a method used to determine the age of field stars by measuring their rotation rate, and then comparing this rate with the rotation rate of the Sun, which serves as a precalibrated clock for this measurement. This method has been seen as a more accurate method for the determination of stellar ages than other methods for field stars.

This makes it possible to determine the age of the coral when it died and the growth rate of the corals. They had several fleshy tentacles that captured small creatures, much like sea anemones. They had a varied growth range, from less than an inch to about a foot long. Finding large corals is hard because it takes decades for them to reach a foot long.

The record's cover is aluminum and electroplated upon it is an ultra-pure sample of the isotope uranium-238. Uranium-238 has a half-life of 4.468 billion years. It is possible (e.g. via mass spectrometry) that a civilization that encounters the record will be able to use the ratio of remaining uranium to the other elements to determine the age of the record.

128; De Bruijn, 1998, p. 112; Prieto and Böhme, 2007, p. 303 In all these localities, it is part of a diverse dormouse fauna.Bolliger, 1992; De Bruijn, 1998; Doukas, 2003; Prieto and Böhme, 2007 Because the distributions of the two known species are temporally distinct, Prieto suggested that the genus may be useful for biostratigraphy (the use of fossils to determine the age of deposits).

Most of the atoms that make up the Earth and its inhabitants were present in their current form in the nebula that collapsed out of a molecular cloud to form the Solar System. The rest are the result of radioactive decay, and their relative proportion can be used to determine the age of the Earth through radiometric dating.Manuel (2001). Origin of Elements in the Solar System, pp.

Once in the lab, they can use equipment such as optical microscopes, in order to actually see evidence of micro organic remains. Archaeologists that look at these microorganisms do not actually find the living bacteria or protist, but instead find indentations left behind in material from where they had been. Depending on where the indentations were in the strata, archaeologists can determine the age of the microorganisms.

Shark teeth cannot be collected from just any type of rock. Any fossils, including fossil shark teeth, are preserved in sedimentary rocks after falling from their mouth. The sediment that the teeth were found in is used to help determine the age of the shark tooth due to the fossilization process. Shark teeth are most commonly found between the Upper Cretaceous and Tertiary periods.

In addition, C. rufifacies are known to be cannibalistic as when the second and third instars feed on young first instars. The larvae are able to burrow inches into the ground to reach food and inhabit a buried corpse. It is proven that organic chemistry can be used to determine the age of post-feeding larvae. The hydrocarbon composition of the larvae was found to correlate with age.

The field was attracting many new workers and laboratories were being improved. As a result, the scientific community was immediately ready to study the new meteorite. A number of museums launched expeditions to Mexico to collect samples, including the Smithsonian Institution and together they collected hundreds of kilograms of material with CAIs. The CAIs are billions of years old, and help to determine the age of the Solar System.

A sample of peat deposit ( in diameter core sample) from the bed of the lake, from its northeastern corner, was taken by coring. This was subject to studies to determine the age of the stratification and the type of biodiversity which existed when it was formed. The pollen spectra revealed a 6,500 year old sequence comprising remnants of pollen and beetle. Coprophagous and coprophilous species of pollen were identified.

Esther Applin (November 24, 1895 – July 23, 1972) was an American geologist and paleontologist. Applin completed her Bachelor of Arts degree in 1919 from the University of California, Berkeley. Later, she completed a Master's degree which was focused on microfossils. She was a leading figure in the use of microfossils to determine the age of rock formation for use in oil exploration in the Gulf of Mexico region.

It is possible to test someone who is at risk for developing DM1 before they are showing symptoms to see whether they inherited an expanded trinucleotide repeat. This is called predictive testing. Predictive testing cannot determine the age of onset that someone will begin to have symptoms, or the course of the disease. If the child is not having symptoms, the testing is not possible with an exception of emancipated minors as a policy.

The puparium is 3.5 to 4.5 mm long, varying in colour from creamy white to yellow-brown, when it is dry. The change in colour of the puparium can determine the age of the pupa. Puparium Adults are 4–5 mm long. In Italy, they are easily recognized in conjunction with other Tephritidae for the small dark spot at the apex of the wing and the length of the narrow, elongated anal cell.

Skeletochronology is a technique used to determine the individual, chronological ages of vertebrates by counting lines of arrested, annual growth, also known as LAGs, within Skeletal tissues. Within the annual bone growth specimens, there are broad and narrow lines. Broad lines represent the growth period and narrow lines represent a growth pause. These narrow lines are what characterises one growth year, therefore make it suitable to determine the age of the specimen.

Incremental dating techniques allow the construction of year-by-year annual chronologies, which can be temporally fixed (i.e., linked to the present day and thus calendar or sidereal time) or floating. Archaeologists use tree-ring dating (dendrochronology) to determine the age of old pieces of wood. Trees usually add growth rings on a yearly basis, with the spacing of rings being wider in high growth years and narrower in low growth years.

The Charlotte whale was among the earliest evidence of this process in Vermont. The skeleton is approximately long and thought to be an adult. Its gender has not been determined. Based on the sediment in which it was found, its age has been estimated at 11,000 or 11,500 years, but due to the way the skeleton was first preserved in 1849, it is impossible to use radiocarbon dating to determine the age of the skeleton.

The Narrabeen Man was found by contractors digging for electricity cables near the corners of Octavia Street and Ocean Street, Narrabeen. A forensic investigation was undertaken and bone samples were sent to Lawrence Livermore National Laboratory in California to determine the age of the remains. Radiocarbon dating of the bone suggested an age of around 4,000 years for the skeleton. The Narrabeen man was suspected to be 30–40 years old when he died.

Oncodella is one of several conodonts used to determine the age of limestone pebbles within Jurassic and Cretaceous-age conglomerate. Conglomerate in Slovakia is known to preserve Oncodella within Rhaetian limestone pebbles transitional between Hallstatt and Zlambach facies. Turonian-age conglomerate from the Sromowce Formation of Poland preserves late Norian pebbles, as indicated by the presence of Oncodella and absence of Misikella posthernsteini. Oncodella fossils have been found in non-reworked limestone in the area as well.

In modern fishes, the cleithrum is a large bone that extends upwards from the base of the pectoral fin and anchors to the cranium above the gills, forming the posterior edge of the gill chamber. The bone has scientific use as a means to determine the age of fishes. The lobe-finned fishes share this arrangement. In the earliest amphibians however, the cleithrum/clavicle complex came free of the skull roof, allowing for a movable neck.

During her leadership at the Department of Archaeology, Usmanova and her team undertook excavations on the site of Erk- Kala, revealing the ancient urbanization of Merv and establishing its age. For this achievement, UNESCO recognized Usmanova alongside Uzbek archaeologist Galina Pugachenkova. In the 1990s, Usmanova led several excavations to determine the age of Shakhrisabz, the birthplace of Amir Temur. In 1997, the Kesh region became a subject of study from the late Bronze Age and early Iron Age.

47 Tucanae, a globular cluster.Membership in a star cluster or star system permits an assignment of rough ages to a large number of stars present within. When one can determine the age of stars through other methods, such as the ones listed above, one can identify the age of all of the bodies in a system. This is especially useful in clusters of stars which exhibit a large amount of variety in their stellar masses, evolutionary stages, and classifications.

The main isotopes of argon found on Earth are (99.6%), (0.34%), and (0.06%). Naturally occurring , with a half-life of 1.25 years, decays to stable (11.2%) by electron capture or positron emission, and also to stable (88.8%) by beta decay. These properties and ratios are used to determine the age of rocks by K–Ar dating. In the Earth's atmosphere, is made by cosmic ray activity, primarily by neutron capture of followed by two- neutron emission.

Finding the average color of the universe was not the focus of the study. Rather, the study examined spectral analysis of different galaxies to study star formation. Like Fraunhofer lines, the dark lines displayed in the study's spectral ranges display older and younger stars and allow Glazebrook and Baldry to determine the age of different galaxies and star systems. What the study revealed is that the overwhelming majority of stars formed about 5 billion years ago.

Beech planted on a march dyke (boundary hedge) of the 18th century. Hedges that have existed for hundreds of years are colonised by additional species. This may be useful to determine the age of the hedge. Hooper's rule based on ecological data obtained from hedges of known age suggests that the age of a hedge can be roughly estimated by counting the number of woody species counted in a thirty-yard distance and multiplying by 110 years.

A sample of basalt pillow lava collected from Lōʻihi, at 1,180 metres below sea level Radiometric dating was used to determine the age of rock samples from Lōʻihi. The Hawaii Center for Volcanology tested samples recovered by various expeditions, notably the 1978 expedition, which provided 17 dredge samples. Most of the samples were found to be of recent origin; the oldest dated rock is around 300,000 years old. Following the 1996 event, some young breccia was also collected.

She spent eighteen months at the Imperial University, Tokyo and explored coal mines on Hokkaido for fossilised plants. She published her Japanese experiences as a diary, called "Journal from Japan: a daily record of life as seen by a scientist", in 1910. In 1910, the Geological Survey of Canada commissioned Stopes to determine the age of the Fern Ledges, a geological structure at Saint John, New Brunswick. It is part of the Early Pennsylvanian epoch Lancaster Formation.

According to Mark W. Chase et al. (2001), the overall biogeography and phylogenetic patterns of Orchidaceae show they are even older and may go back roughly 100 million years. Using the molecular clock method, it was possible to determine the age of the major branches of the orchid family. This also confirmed that the subfamily Vanilloideae is a branch at the basal dichotomy of the monandrous orchids, and must have evolved very early in the evolution of the family.

All of these decays are alpha or beta decays, meaning that they all follow first order rate equations of the form dN/dt=\lambda N, where λ is the half-life of the isotope in question. This makes it simple to determine the age of a sample based on the various ratios of radioactive isotopes that exist. One way uranium isotopes are used is to date rocks from millions to billions of years ago. This is through uranium-lead dating.

Radiocarbon dating has been used since 1946 to determine the age of organic material as old as 50,000 years. As the organism dies, the exchange of 14C with the environment ceases and the incorporated 14C decays. Given the steady decay of radioisotopes (the half-life of 14C is about 5,730 years), the relative amount of 14C left in the dead organism can be used to calculate how long ago it died. Bomb pulse dating should be considered a special form of carbon dating.

Calculating the abundance of these nuclides is a way to determine the age of exposure of surface rock, also called Surface Exposure Dating. This approach has been used on Scandinavian, Antarctic, & Greenland ice sheets, and is now being applied to glacially eroded boulder and bedrock surfaces from various mountains in New England, such as Mount Greylock. The research supports rapid de-glaciation in New England around the retreat of the Laurentide Ice Sheet, which further constrains previous estimates of the LIS thinning rate.

Radiometric dating is how geologist determine the age of a rock. In a closed system, the amount of radiogenic isotopes present in a sample is a direct function of time and the decay rate of the mineral. Therefore, to find the age of a sample, geologists find the ratio of daughter isotopes to remaining parent isotopes present in the mineral through different methods, such as mass spectrometry. From the known parent isotopes and the decay constant, we can then determine the age.

The impact has been dated to 2,229±5 million years ago, making it the world’s oldest confirmed impact crater. This date places the impact at the end of the first period when the Earth was mostly or completely frozen, commonly called the Huronian glaciation. The age finding was based on analysis of ancient crystals of the minerals zircon and monazite found in the crater. Scientists used uranium-lead dating to analyze the samples and to determine the age of the impact crater.

Detail of engraving on memorial stone, left Vocel's literary work reflects a pathological interest in medieval history, archeology and historiography. By and large his two most significant works are thought to be Poslední Orebit and Přemyslovci. In 1850 Vocel was appointed Associate Professor of Archeology and Art History at the Charles University. As author of numerous articles and scientific papers he inadvertently introduced what would later become a widely accepted method of chemical analysis to determine the age of bronze objects.

Shalihotra's principal work was a large treatise on the care and management of horses, the Shalihotra Samhita (encyclopedia of the physician Shalihotra) having some 12,000 shlokas in Sanskrit. It has been translated into Persian, Arabic, Tibetan and English languages. This work described equine and elephant anatomy, physiology, surgery and diseases with their curative and preventive measures. It elaborated on the body structures of different races of horses, and identified the structural details by which one can determine the age of a horse.

All three rodent species indicate an age no older than the latest Miocene, about five million years ago, and no younger than the early Pliocene. Scientists also used paleomagnetic dating to determine the age of the sediment layer from which the cranium was recovered. The cranium shares the dental morphology expressed by two other species of Lufengpithecus, L. lufengensis and L. hudienensis. Only the first molars of ZT 299 are erupted, and judging by the amount of wear, they had been in use for some time.

Haglof increment borer An increment borer is a specialized tool used to extract a section of wood tissue from a living tree with relatively minor injury to the plant itself. The tool consists of a handle, an auger bit and a small, half circular metal tray ( the core extractor) that fits into the auger bit; the last is usually manufactured from carbide steel. It is most often used by foresters, researchers and scientists to determine the age of a tree. This science is also called dendrochronology.

Researchers use radioactive atoms to determine the age of materials that were once part of a living organism. The age of such materials can be estimated by measuring the amount of radioactive carbon they contain in a process called radiocarbon dating. Similarly, using other radioactive elements, the age of rocks and other geological features (even some man-made objects) can be determined; this is called Radiometric dating. Environmental scientists use radioactive atoms, known as tracer atoms, to identify the pathways taken by pollutants through the environment.

It is thought that its surface contains tholins, which are irradiated organic compounds that are more common in objects in the outer Solar System and can help determine the age of the surface. Also here at Phys.org This possibility is inferred from spectroscopic characterization and its dark and reddened color, and from the expected effects of interstellar radiation. Despite the lack of any cometary coma when it approached the Sun, it may still contain internal ice, hidden by "an insulating mantle produced by long-term cosmic ray exposure".

Layered lamellar bone makes up most of the neural spine's cross-sectional area, and contains lines of arrested growth that can be used to determine the age of each individual at death. In many specimens of D. gigashomogenes the distal portions of spines bend sharply, indicating that the sail would have had an irregular profile in life. Their crookedness suggests that soft tissue may not have extended all the way to the tips of the spines, meaning that the sail's webbing may not have been as extensive as it is commonly imagined.

Radiocarbon dating is a radiometric dating method that uses (14C) to determine the age of carbonaceous materials up to about 60,000 years old. The technique was developed by Willard Libby and his colleagues in 1949 during his tenure as a professor at the University of Chicago. Libby estimated that the radioactivity of exchangeable carbon-14 would be about 14 disintegrations per minute (dpm) per gram of pure carbon, and this is still used as the activity of the modern radiocarbon standard. In 1960, Libby was awarded the Nobel Prize in chemistry for this work.

The 1979 amendment clarified the role of the IPHC in the management of the fishery through the North Pacific Halibut Act of 1982. It has carried out many activities including the use of chartered commercial fishing vessels to undertake bottom trawls and long-lining for sampling fish stocks, banding fish, recording water temperatures using bathythermographs, etc., in the North Pacific and Bering Sea for many years. Also, staff have been stationed at on-shore fish processing plants to sample catches, remove otoliths to determine the age of the fish, and many other research activities.

In 1909, the priority was finally granted to Urbain and his names were adopted as official ones; however, the name cassiopeium (or later cassiopium) for element 71 proposed by Welsbach was used by many German scientists until the 1950s. Lutetium is not a particularly abundant element, although it is significantly more common than silver in the earth's crust. It has few specific uses. Lutetium-176 is a relatively abundant (2.5%) radioactive isotope with a half-life of about 38 billion years, used to determine the age of minerals and meteorites.

In order to determine the age of this site, a series of U/Th dating were carried out on geological and archaeological samples obtained in 1995 excavation season from the upper most and lowest levels of the stratigraphic sequence. The archaeological results provide the age of 121 +11/-10 kya for the upper most level and >369 kya for the lowest one. Alternatively, the geology provides about 400 kya for the oldest sample. These dates place the Cave of the Angel site in the Middle and Upper Pleistocene periods.

Same as geologists or paleontologists, archaeologists are also brought to determine the age of ancient both ancient and recent humans. Thus, to be considered as archaeological, the remains, objects or artifacts to be dated must be related to human activity. It is commonly assumed that if the remains or elements to be dated are older than the human species, the disciplines which study them are sciences such geology or paleontology, among some others. Nevertheless, the range of time within archaeological dating can be enormous compared to the average lifespan of a singular human being.

She uses this to determine the star structure and inform stellar models within stellar evolution theory. With these techniques she has made a number of discoveries, including that of non-non-rigid rotation in giant stars. The theoretical models she develops based on the star oscillations also allow her determine the age of stars with a high accuracy. Aerts has twice been awarded an Advanced Grant by the European Research Council (ERC): in 2008 for PROSPERITY, and again in 2015 for a project entitled MAMSIE (Mixing and Angular Momentum Transport of Massive Stars).

Work was continued by Joaquín Matilló, Allan L. Bryan and Jorge Espinosa in the 1960s and 1970s. Allan L. Bryan, from the University of Alberta, used radiocarbon dating to determine the age of soil humates, from a buried soil directly underlying the footprints, to 5,945±145 radiocarbon years Before Present. Based upon this date, he estimated that the footprints dated to about 5,000 Before Present. But, later dating of the volcanic deposits in which they occur, known as the Masaya Triple Layer, demonstrated that the fossil tracks are only about 2,120 ± 120 years old.

Esarhaddon, who reigned as king of Assyria from 681–669 BC, had several daughters, but Serua-eterat is the only one known by name. Her name frequently appears in contemporary inscriptions.' At least one other daughter, though unnamed, is known from lists of the royal children and Serua-eterat is explicitly designated as the "eldest daughter", meaning there would have been other princesses. Because lists of the royal children are inconsistent in order, it is difficult to determine the age of Serua-eterat relative to her male siblings.

With Jules Germain Cloquet (1790–1883), he translated William Lawrence's work on hernias from English into French as Traité des hernies. Pierre Béclard is credited with introducing new amputative and surgical practices, performing in 1823 an extirpation of the parotid gland.Bibliography of Béclard @ Who Named It His name is lent to the eponymous "Béclard's nucleus", defined as the core of ossification in the cartilage of the distal epiphysis of the femur during the latter part of fetal life. It is used in forensic medicine to determine the age of a fetus or newborn infant.

Attempts have been made to determine the age of this feature using different techniques. These include direct radiocarbon dating of the stones composing the Bimini Road and Uranium-thorium dating of the marine limestone on which the Bimini Road lies. In 1978, the radiocarbon laboratory operated by the Department of Geology at the University of Miami dated samples from a core collected by E. A. Shinn in 1977 from the Bimini Road. In 1979, Calvert and othersCalvert, P.M., D.S. Introne, J.J. Stipp, 1979, University of Miami radiocarbon dates XIV. Radiocarbon. v.

2004 Nobel Prize in Physics winner H. David Politzer is a current professor at Caltech, as is astrophysicist and author Kip Thorne and eminent mathematician Barry Simon. Linus Pauling pioneered quantum chemistry and molecular biology, and went on to discover the nature of the chemical bond in 1939. Seismologist Charles Richter, also an alumnus, developed the magnitude scale that bears his name, the Richter magnitude scale for measuring the power of earthquakes. One of the founders of the geochemistry department, Clair Patterson was the first to accurately determine the age of the Earth via lead:uranium ratio in meteorites.

As groundwater seeped into cracks in the marble, it eventually dissolved enough rock to expand some of the cracks to the size of tunnels. Generally, the age of a cave cannot be determined directly because the cave itself is an empty space, but scientists can sometimes determine the age of speleothems or sediments in a cave. An early 21st-century study of speleothem development in Oregon Caves focused on the past 380,000 years. Based on the available evidence, the cave is thought to be at least a million years old and "probably not much older than a few million" years.

In 2013, the supernova 2013ej was discovered by KAIT in the galaxy Messier 74; it was noted for being as bright as 10th magnitude. In 2014, KAIT helped determine the age of a supernova found in the galaxy M83, because it had images of that region of the sky from just a few days prior to its discovery, establishing it had not brightened at that time. In 2016, KAIT spotted the super nova SN 2016coj in NGC 4125, thought to be a Type Ia supernova. In 2019, KAIT was one of the telescopes whose data was used in a study on Blazars.

Photographs and measurements of wing and tail feathers were taken from each individual, as well as small feather samples for genetic analysis. Growth bars visible on the tail feathers can help scientists determine the age of the bird, and comparison of photographs and measurements with results of lab analyses will aid in finding a way to sex Nihoa millerbirds in the field. Development of these methods will ensure that the right numbers of male and female birds are moved to Laysan. Several Nihoa millerbirds were placed in a temporary enclosure and presented with a selection of island insects.

In 2013, Yale astronomer Pascal Oesch spotted an unexpected bright object while looking at Hubble Space Telescope images. He then confirmed the existence of the object using the Spitzer Space Telescope. Redshift calculations, using the Multi-Object Spectrometer for Infrared Exploration (MOSFIRE) equipment at the W.M. Keck Observatory in Hawaii, were then performed to precisely determine the age of the galaxy. Oesch and his colleagues at Yale and the University of California, Santa Cruz announced the find, which was named EGS-zs8-1, in May 2015 surpassing the previous record for oldest galaxy by about 30 million years.

In 1849 he made the first discovery of tin in Australia and in 1859 he made known the occurrence of diamonds. He discovered secondary (Cretaceous) fossils in Queensland in 1860, he was also the first to indicate the presence of Silurian rocks, and to determine the age of the coal- bearing rocks in New South Wales. In 1869 he announced the discovery of remains of Dinornis in Queensland. He finished the preparation of the fourth edition of his Remarks on the Sedimentary Formations of New South Wales on his eightieth birthday, and died a fortnight later on 16 June 1878.

Not only can the age of a human specimen be narrowed by evaluating the patterns of tooth eruption and tooth wear, recent studies provide evidence that cementum, the mineralized tissue that lines the surface of tooth roots, exhibits annual patterns of deposition. Aggrawal has presented a comprehensive account. The Royal College of Paediatrics and Child Health (RCPCH) has described dental x-rays to determine the age of asylum seekers as "imprecise" and "inappropriate". According to Tim Cole, Professor of medical statistics at the Great Ormond Street Institute of Child Health, dental x-ray tests are "very inaccurate" in determining a precise age.

Another important technique in testing samples from a historic or archaeological site is a process known as thermoluminescence testing, which involves the principle that all objects absorb radiation from the environment. This process frees electrons within elements or minerals that remain caught within the item. Thermoluminescence testing involves heating a sample until it releases a type of light, which is then measured to determine the last time the item was heated. In thermoluminescence dating, these long-term traps are used to determine the age of materials: When irradiated crystalline material is again heated or exposed to strong light, the trapped electrons are given sufficient energy to escape.

The amount of C in the atmosphere and in living organisms is almost constant, but decreases predictably in their bodies after death. This principle is used in radiocarbon dating, invented in 1949, which has been used extensively to determine the age of carbonaceous materials with ages up to about 40,000 years. There are 15 known isotopes of carbon and the shortest-lived of these is C which decays through proton emission and alpha decay and has a half-life of 1.98739 × 10 s. The exotic C exhibits a nuclear halo, which means its radius is appreciably larger than would be expected if the nucleus were a sphere of constant density.

Klein identifies three pairs of bones to which he attributes the sense of hearing, and he takes to correspond to the Incus, Malleus and Stapes of other animals. The first are the two largest, which he explains are easily found; the other two pairs, he explains, are small, difficult to find, enveloped in distinct fine membranes. Klein believed one could determine the age of fish by analysing the number and thickness of the Laminae and fibres of these bones. The bone to which Klein was referring, now called the otolith, acquires a growth ring every day for at least the first six months of its life.

Split trunk section where the church oil tank was formerly located. This yew tree lives in the churchyard of St. Digain's Church in Llangernyw village. Although it is very hard to determine the age of yew trees,Harte 1996Kinmonth 2006 the churchyard gate holds a certificate from the Yew Tree Campaign in 2002, signed by David Bellamy, which states that "according to all the data we have to hand" the tree is dated to between 4,000 and 5,000 years old. There is an alternative theory that presumes the tree is only as old as the adjacent saint site, which would make it around 1,500 years old.

Boltwood was inspired to describe the relationships between elements in various decay series. Late in 1904, Rutherford took the first step toward radiometric dating by suggesting that the alpha particles released by radioactive decay could be trapped in a rocky material as helium atoms. At the time, Rutherford was only guessing at the relationship between alpha particles and helium atoms, but he would prove the connection four years later. Soddy and Sir William Ramsay had just determined the rate at which radium produces alpha particles, and Rutherford proposed that he could determine the age of a rock sample by measuring its concentration of helium.

This number represents an accurate "direct" measurement of the age of the universe (other methods typically involve Hubble's law and the age of the oldest stars in globular clusters, etc.). It is possible to use different methods for determining the same parameter (in this case – the age of the universe) and arrive at different answers with no overlap in the "errors". To best avoid the problem, it is common to show two sets of uncertainties; one related to the actual measurement and the other related to the systematic errors of the model being used. An important component to the analysis of data used to determine the age of the universe (e.g.

A rare collection of artifacts from an archeological dig in Egypt are brought to the famous Musée du Louvre in Paris. While experts are using a laser scanning device to determine the age of a sarcophagus, a spirit escapes and makes its way into the museum's electrical system. Museum curator Faussier (Jean- Francois Balmer) brings in noted Egyptologist, Glenda Spencer (Julie Christie), to examine the findings, and she announces that the mummy inside the coffin was actually the evil spirit Belphegor. Meanwhile, Lisa (Sophie Marceau), a young woman who lives across the street from the museum, follows her runaway cat into the Louvre after closing time.

The calculations to be performed on the measurements taken depend on the technology used, since beta counters measure the sample's radioactivity whereas AMS determines the ratio of the three different carbon isotopes in the sample. To determine the age of a sample whose activity has been measured by beta counting, the ratio of its activity to the activity of the standard must be found. To determine this, a blank sample (of old, or dead, carbon) is measured, and a sample of known activity is measured. The additional samples allow errors such as background radiation and systematic errors in the laboratory setup to be detected and corrected for.

Uranium–thorium dating, also called thorium-230 dating, uranium-series disequilibrium dating or uranium-series dating, is a radiometric dating technique established in the 1960s which has been used since the 1970s to determine the age of calcium carbonate materials such as speleothem or coral. Unlike other commonly used radiometric dating techniques such as rubidium–strontium or uranium–lead dating, the uranium-thorium technique does not measure accumulation of a stable end-member decay product. Instead, it calculates an age from the degree to which secular equilibrium has been restored between the radioactive isotope thorium-230 and its radioactive parent uranium-234 within a sample.

Pollens contributed the chapter on dendrochronology, a scientific procedure used to determine the age of the wood used in making violins. The Early Pianoforte (1995) traces the history of the piano from its invention up to the mid 18th century. It offers thorough coverage of the career of Bartolomeo Cristofori, widely acknowledged as having invented the piano in Florence around 1700, but rather contentiously suggests that Cristofori should not be called the instrument's inventor. In support of this claim it carefully goes through the threads of evidence that can be found for the existence of piano- like instruments dating as far back as 1440.

Perennial herb species belonging to the dicotyledon group (also known as perennial forbs) are characterized by secondary growth, which shows as a new growth ring added each year to persistent roots. About two thirds of all perennial dicotyledonous herb species with a persistent root that grow in the strongly seasonal zone of the northern hemisphere show at least fairly clear annual growth rings. Counting of annual growth rings can be used to determine the age of a perennial herb similarly as it is done in trees using dendrochronology. This way it was found that some perennial herbs live up to 50 years and more.

Inflorescence bud scales in Halesia carolina The buds of many woody plants, especially in temperate or cold climates, are protected by a covering of modified leaves called scales which tightly enclose the more delicate parts of the bud. Many bud scales are covered by a gummy substance which serves as added protection. When the bud develops, the scales may enlarge somewhat but usually just drop off, leaving a series of horizontally-elongated scars on the surface of the growing stem. By means of these scars one can determine the age of any young branch, since each year's growth ends in the formation of a bud, the formation of which produces an additional group of bud scale scars.

Although physical characteristics and sizes at various instars have been used to estimate fly age, a more recent study has been conducted to determine the age of an egg based on the expression of particular genes. This is particularly useful in determining developmental stages that are not evidenced by change in size; such as the egg or pupa and where only a general time interval can be estimated based on the duration of the particular developmental stage. This is done by breaking the stages down into smaller units separated by predictable changed in gene expression. Three genes were measured in an experiment with Drosophila melanogaster: bicoid (bcd), slalom (sll), and chitin synthase (cs).

As discussed above and in the Radiolab episode, Elements (section 'Carbon'), in bomb pulse dating the slow absorption of atmospheric 14C by the biosphere, can be considered as a chronometer. Starting from the pulse around the years 1963 (see figure), atmospheric radiocarbon relative abundance decreased by about 4% a year. So in bomb pulse dating it is the relative amount of 14C in the atmosphere that is decreasing and not the amount of 14C in a dead organisms, as is the case in classical radiocarbon dating. This decrease in atmospheric 14C can be measured in cells and tissues and has permitted scientists to determine the age of individual cells and of deceased people.

Researchers have worked to determine the age of the Pumapunku complex since the discovery of the Tiwanaku site. As noted by Andean specialist, W. H. Isbell, professor at Binghamton University, a radiocarbon date was obtained by Vranich from organic material from the lowermost and oldest layer of mound-fill forming the Pumapunku. This layer was deposited during the first of three construction epochs and dates the initial construction of the Pumapunku to AD 536–600 (1510 ±25 B.P. C14, calibrated date). Since the radiocarbon date came from the lowermost and oldest layer of mound-fill underlying the andesite and sandstone stonework, the stonework must have been constructed sometime after AD 536–600.

From barium (Z=56) on, all elements show the pattern of the r-process contribution to the abundances of the elements in the Solar System. Comparing the observed abundances for a stable element such as europium (Z=63) and the radioactive element thorium (Z=90) to calculated abundances of an r-process in a type II supernova explosion (as from the universities at Mainz and Basel groups of Karl-Ludwig Kratz and Friedrich-Karl Thielemann) have allowed observers to determine the age of this star to be about 13 billion years. Similar ages have been derived for other ultra-metal-poor stars (CS31082-001, BD +17° 3248 and HE 1523-0901) from thorium-to-uranium ratios.

As stars grow older, their luminosity increases at an appreciable rate. Given the mass of the star, one can use this rate of increase in luminosity in order to determine the age of the star. This method only works for calculating stellar age on the main sequence, because in advanced evolutionary stages of the star, such as the red giant stage, the standard relationship for the determination of age no longer holds. However, when one can observe a red giant star with a known mass, one can calculate the main-sequence lifetime, and thus the minimum age of star is known given that it is in an advanced stage of its evolution.

The potassium-argon method was utilized to determine the age of volcanism at Pilot Knob. This method is based upon the decay of the radioactive isotope of potassium (potassium 40) to argon 40, an isotope of argon, an inert gas. By knowing the concentration of potassium in a rock mineral and the amount of argon gas produced by radioactive decay trapped within the minerals, an age can be assigned to the rock because the decay rate of potassium 40 to argon 40 is known from experimental work. The age of Pilot Knob volcanism dated through the potassium-argon method is 79.5 +/- 3 million years, and agrees with the age derived by correlation with fossils to other radiometrically dated deposits.

In 1987, Fontaine along with his collaborators, attempted to determine the age of the Universe using the amount of time it takes for white dwarfs to cool. Comparing observations to numerical simulations, the found that the Universe is between 10 billion and 300 million years old. In 1990, his group published the first results from the Whole Earth Telescope, a network of telescopes around the world located at different longitudes that could collectively provide continuous observations of pulsating white dwarfs. In 1996, the asteroseismology group at the Université de Montréal once again predicted a new type of variable star, a B-type white subdwarf, which was confirmed by observations by the South African Astronomical Observatory in 1997.

The volcanism that occurred in the Siberian Traps resulted in copious amounts of magma being ejected from the Earth's crust—leaving permanent traces of rock from the same time period of the mass extinction that is able to be examined today. More specifically, zircon is found in some of the volcanic rocks. To further the accuracy of the age of the zircon, several varying aged pieces of zircon were organized into a timeline based on when they crystallized. The CA-TIMS technique, a chemical abrasion age-dating technique that eliminates variability in accuracy due to lead depletion in zircon over time, was then used to accurately determine the age of the zircons found in the Siberian Traps.

While inspired by ancient texts and sometimes using them to interpret artifacts, classical archaeology would not exist without ancient artifacts. Though much of classical archaeology (like any kind of archaeology) is performed by scholars in their studies, the most vibrant and crucial parts of classical archaeology are the archaeological excavations, more commonly known as "digs". Excavation techniques at first were modelled after excavations in Egypt and the Near East and searched for large artifacts and walls without much care for the delicate remains that might have existed in the ground around these artifacts. Many of the earliest sites still cannot be dated in a satisfying manner because the stratigraphy, soil layers with embedded artifacts used to determine the age of a site, was completely stripped away.

Reconstruction of the Girl of the Uchter Moor Until the mid-20th century, it was not readily apparent at the time of discovery whether a body had been buried in a bog for years, decades, or centuries. But, modern forensic and medical technologies (such as radiocarbon dating) have been developed that allow researchers to more closely determine the age of the burial, the person's age at death, and other details. Scientists have been able to study the skin of the bog bodies, reconstruct their appearance and even determine what their last meal was from their stomach contents since peat marsh preserves soft internal tissue. Their teeth also indicate their age at death and what type of food they ate throughout their lifetime.

The rubidium-strontium dating method is a radiometric dating technique used by scientists to determine the age of rocks and minerals from the quantities they contain of specific isotopes of rubidium (87Rb) and strontium (87Sr, 86Sr). Development of this process was aided by German chemists Otto Hahn and Fritz Strassmann, who later went on to discover nuclear fission in December 1938. The utility of the rubidium–strontium isotope system results from the fact that 87Rb (one of two naturally occurring isotopes of rubidium) decays to 87Sr with a half-life of 49.23 billion years. In addition, Rb is a highly incompatible element that, during partial melting of the mantle, prefers to join the magmatic melt rather than remain in mantle minerals.

The boulder had shifted and settled onto the victim, a pre-Columbian miner, who had disturbed the rubble supporting it. The remains of the ancient victim were named "Lost John" and exhibited to the public into the 1970s, when they were interred in a secret location in Mammoth Cave for reasons of preservation as well as emerging political sensitivities with respect to the public display of Native American remains. Research beginning in the late 1950s led by Patty Jo Watson, of Washington University in St. Louis, Missouri, has done much to illuminate the lives of the late Archaic and early Woodland peoples who explored and exploited caves in the region. Preserved by the constant cave environment, dietary evidence yielded carbon dates enabling Watson and others to determine the age of the specimens.

As they develop and grow in size, the larvae will make the hole bigger, therefore the size of the burrow will determine the age of the larvae. The larval stage depends on not only the species of Cicindela, but also the frequency of food, and the climate, however the larval stage will generally only last for one to two years depending on these resources. Once the larvae are ready to pupate they do so and this stage is very brief, beginning in February, which is when the larval population declines to a point where they are no longer seen. When it is pupating, the larvae plugs the hole of its burrow and descends to the bottom of the burrow where it digs a side cavity to pupate in.

According to information on the government DVLA website: "Just remember you can make your vehicle look as old as you wish but you can not make it look newer than it is. For example you cannot put a Y registration number on a T registered vehicle but you could choose any prefix range from an A to a T. Each registration has an issue date which is what you must check to ensure you don't make your vehicle appear newer than it is." However, you are able to put 1955 registered private number plates on a 1949 registered vehicle as there is no year indicator to determine the age of release. As many vehicles registered before 1963 have been scrapped, some of their "dateless" pre-1963 registration numbers have been transferred to other vehicles as personal plates.

At the time, Megalosaurus was used as a "wastebasket taxon", wherein many species of theropods were placed, regardless of their age or locality. Reconstructed skull, showing the two crests that were the basis of the name Dilophosaurus, American Museum of Natural History Welles returned to Tuba City in 1964 to determine the age of the Kayenta Formation (it had been suggested to be Late Triassic in age, whereas Welles thought it was Early to Middle Jurassic), and discovered another skeleton about south of where the 1942 specimens had been found. The nearly complete specimen (catalogued as UCMP 77270) was collected with the help of William Breed of the Museum of Northern Arizona and others. During preparation of this specimen, it became clear that it was a larger individual of M. wetherilli, and that it would have had two crests on the top of its skull.

Due to the efforts of influential Christian scholars and clerics such as James Ussher, who sought to determine the age of Earth through analysis of genealogies in Scripture, Westerners before the 19th century generally believed Earth to be a few thousand years old at most. It was only during the 19th century that geologists realized Earth's age was at least many millions of years. Lord Kelvin used thermodynamics to estimate the age of Earth to be between 20 million and 400 million years in 1864, sparking a vigorous debate on the subject; it was only when radioactivity and radioactive dating were discovered in the late 19th and early 20th centuries that a reliable mechanism for determining Earth's age was established, proving the planet to be billions of years old. The perception of Earth shifted again in the 20th century when humans first viewed it from orbit, and especially with photographs of Earth returned by the Apollo program.

Two radiometric dating methods involve thorium isotopes: uranium–thorium dating, based on the decay of 234U to 230Th, and ionium–thorium dating, which measures the ratio of 232Th to 230Th. These rely on the fact that 232Th is a primordial radioisotope, but 230Th only occurs as an intermediate decay product in the decay chain of 238U. Uranium–thorium dating is a relatively short-range process because of the short half-lives of 234U and 230Th relative to the age of the Earth: it is also accompanied by a sister process involving the alpha decay of 235U into 231Th, which very quickly becomes the longer-lived 231Pa, and this process is often used to check the results of uranium–thorium dating. Uranium–thorium dating is commonly used to determine the age of calcium carbonate materials such as speleothem or coral, because uranium is more soluble in water than thorium and protactinium, which are selectively precipitated into ocean-floor sediments, where their ratios are measured.

The scale of changes resulting in the production of carbon-14 in one cycle is small (about one percent of medium abundance) and can be taken into account when radiocarbon dating is used to determine the age of archaeological artifacts. The interpretation of the beryllium-10 and carbon-14 cosmogenic isotope abundance records stored in terrestrial reservoirs such as ice sheets and tree rings has been greatly aided by reconstructions of solar and heliospheric magnetic fields based on historic data on Geomagnetic storm activity, which bridge the time gap between the end of the usable cosmogenic isotope data and the start of modern spacecraft data. PDF Copy PDF Copy Other historical sunspot minima have been detected either directly or by the analysis of the cosmogenic isotopes; these include the Spörer Minimum (1450–1540), and less markedly the Dalton Minimum (1790–1820). In a 2012 study, sunspot minima have been detected by analysis of carbon-14 in lake sediments.

The Parlington estate was acquired by the Gascoignes from the Wentworth family in 1546. The hall was modified by successive family members, before it was abandoned in the early years of the twentieth century it was a culmination of alterations by Sir Edward Gascoigne (early eighteenth century), his son Sir Thomas Gascoigne the last baronet (late eighteenth century), Richard Oliver-Gascoigne (early nineteenth century) and last by Isabella and her husband Frederick in the mid and late nineteenth century. The extent of the mansion by the turn of the twentieth century, its mixed architecture and myriad of materials presented an incoherent design, perhaps only improved by the highly regarded landscaped gardens, often cited in local newspaper articles. Sadly after it was abandoned the incremental demolition between the second decade of the twentieth century and the late nineteen fifties destroyed any ability to determine the age of the earliest parts of the property, most of that seen in any photographs is later than the seventeenth century. Sir Thomas Gascoigne, 8th and last Baronet, succeeded his brother in 1762. Sir Thomas was M.P. for Thirsk from 1780 to 1784, for Malton in 1784 and for Arundel in 1795.

The episode describes how science, in particular the work of Clair Patterson (voiced in animated sequences by Richard Gere) in the middle of the 20th century, has been able to determine the age of the Earth. Tyson first describes how the Earth was formed from the coalescence of matter some millions of years after the formation of the Sun, and while scientists can examine the formations in rock stratum to date some geological events, these can only trace back millions of years. Instead, scientists have used the debris from meteor impacts, such as the Meteor Crater in Arizona, knowing that the material from such meteors coming from the asteroid belt would have been made at the same time as the Earth. Tyson then outlines the work Patterson did as a graduate under his adviser Harrison Brown to provide an accurate count of lead in zircon particles from Meteor Crater, and to work with similar results being collected by George Tilton on uranium counts; with the established half-life of uranium's radioactive decay to lead, this would be used to estimate the age of the Earth.

Cross sectioned tusk with growth rings, which can be used to determine the age of specimens The lifespan of mammals is related to their size, and since modern elephants can reach the age of 60 years, the same is thought to be true for woolly mammoths, which were of a similar size. The age of a mammoth can be roughly determined by counting the growth rings of its tusks when viewed in cross section, but this does not account for its early years, as these are represented by the tips of the tusks, which are usually worn away. In the remaining part of the tusk, each major line represents a year, and weekly and daily ones can be found in between. Dark bands correspond to summers, so determining the season in which a mammoth died is possible. The growth of the tusks slowed when foraging became harder, for example during winter, during disease, or when a male was banished from the herd (male elephants live with their herds until about the age of 10). Mammoth tusks dating to the harshest period of the last glaciation 25–20,000 years ago show slower growth rates.

The least stable is 29Ar with a half- life of approximately seconds. The naturally occurring 40K, with a half-life of 1.248 years, decays to stable 40Ar by electron capture (10.72%) and by positron emission (0.001%), and also transforms to stable 40Ca via beta decay (89.28%). These properties and ratios are used to determine the age of rocks through potassium–argon dating. Despite the trapping of 40Ar in many rocks, it can be released by melting, grinding, and diffusion. Almost all of the argon in the Earth's atmosphere is the product of 40K decay, since 99.6% of Earth atmospheric argon is 40Ar, whereas in the Sun and presumably in primordial star-forming clouds, argon consists of < 15% 38Ar and mostly (85%) 36Ar. Similarly, the ratio of the three isotopes 36Ar:38Ar:40Ar in the atmospheres of the outer planets is measured to be 8400:1600:1. In the Earth's atmosphere, radioactive 39Ar (half-life 269 years) is made by cosmic ray activity, primarily from 40Ar. In the subsurface environment, it is also produced through neutron capture by 39K or alpha emission by calcium. The content of 39Ar in natural argon is measured to be of (8.0±0.6)×10−16 g/g, or (1.01±0.08) Bq/kg of 36, 38, 40Ar.