If you want to get weird, start reading up on Mercury and Venus' solar days.
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The team&aposs work suggests that these bits of dust are a relic of the pre-solar days.
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Almost all of the power on the island is supplied by fossil fuels, but Puerto Rico is "an ideal locale to use solar power and renewable energy because it has so many more solar days than in many parts of the world," said Mr. Marvel, whose offices are based in Manhattan and San Juan.
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The duration of the nodical month is approximately 27.2122 mean solar days.
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The Gregorian calendar improves the approximation made by the Julian calendar by skipping three Julian leap days in every 400 years, giving an average year of 365.2425 mean solar days long.Seidelmann (1992), pp. 580–581. This approximation has an error of about one day per 3,030 yearsUsing value from Richards (2013, p. 587) for tropical year in mean solar days, the calculation is with respect to the current value of the mean tropical year.
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The relative proximity of the Moon at this time meant that tides were stronger and more rapid than they are now. The day was 21.9±0.4 hours, and there were 13.1±0.1 synodic months/year and 400±7 solar days/year.
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On the past field were run and covered by rain flooding; now it is believed that the drainage system of these fields is pretty functional. The average temperature in summer is 30-37 degrees Celsius and 0-10 in winter. Average solar days are 292 annually.
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When viewed over a one-year period, the mean longitude is very nearly a linear function of Terrestrial Time. To find the length of the tropical year, the mean longitude is differentiated, to give the angular speed of the Sun as a function of Terrestrial Time, and this angular speed is used to compute how long it would take for the Sun to move 360° (; Astronomical Almanac for the year 2011, L8). The above formulae give the length of the tropical year in ephemeris days (equal to 86,400 SI seconds), not solar days. It is the number of solar days in a tropical year that is important for keeping the calendar in synch with the seasons (see below).
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The Vikram Samvat has been used by Hindus and Sikhs. One of several regional Hindu calendars in use on the Indian subcontinent, it is based on twelve synodic lunar months and 365 solar days. The lunar year begins with the new moon of the month of Chaitra.Davivajña, Rāma (1996) Muhurtacintāmaṇi.
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In the 16th century Copernicus put forward a heliocentric cosmology. Erasmus Reinhold used Copernicus' theory to compute the Prutenic Tables in 1551, and gave a tropical year length of 365 solar days, 5 hours, 55 minutes, 58 seconds (365.24720 days), based on the length of a sidereal year and the presumed rate of precession. This was actually less accurate than the earlier value of the Alfonsine Tables.
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An increase of 360° in the ERA is a full rotation of the Earth. Because Earth orbits the Sun once a year, the sidereal time at any given place and time will gain about four minutes against local civil time, every 24 hours, until, after a year has passed, one additional sidereal "day" has elapsed compared to the number of solar days that have gone by.
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Major advances in the 17th century were made by Johannes Kepler and Isaac Newton. In 1609 and 1619 Kepler published his three laws of planetary motion . In 1627, Kepler used the observations of Tycho Brahe and Waltherus to produce the most accurate tables up to that time, the Rudolphine Tables. He evaluated the mean tropical year as 365 solar days, 5 hours, 48 minutes, 45 seconds (365.24219 days; ).
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Also, the mean solar day is getting longer at a rate of about 1.5 ms per century. These effects will cause the calendar to be nearly a day behind in 3200. The number of solar days in a "tropical millennium" is decreasing by about 0.06 per millennium (neglecting the oscillatory changes in the real length of the tropical year).365242×1.5/8640000. This means there should be fewer and fewer leap days as time goes on.
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Because it begins a month earlier than the Iditarod, the Quest is a colder race, and is run on shorter solar days and through longer, darker nights. Sonny Lindner won the inaugural race in 1984 from a field of 26 teams. The fastest run took place in 2010, when Hans Gatt finished after 9 days and 26 minutes. The 2012 competition had the closest one-two finish, as Hugh Neff beat Allen Moore by twenty-six seconds.
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The time for one complete rotation is 23 hours, 56 minutes, and 4.09 seconds – one sidereal day. The first experimental demonstration of this motion was conducted by Léon Foucault. Because Earth orbits the Sun once a year, the sidereal time at any given place and time will gain about four minutes against local civil time, every 24 hours, until, after a year has passed, one additional sidereal "day" has elapsed compared to the number of solar days that have gone by.
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Mercury's sidereal day is about two- thirds of its orbital period, so by the prograde formula its solar day lasts for two revolutions around the Sun – three times as long as its sidereal day. Venus rotates retrograde with a sidereal day lasting about 243.0 Earth days, or about 1.08 times its orbital period of 224.7 Earth days; hence by the retrograde formula its solar day is about 116.8 Earth days, and it has about 1.9 solar days per orbital period. By convention, rotation periods of planets are given in sidereal terms unless otherwise specified.
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Syncellus goes so far as to insinuate that the two copied each other: While this does seem an incredible coincidence, the reliability of the report is unclear. The reasoning for assuming they started their histories in the same year involved some considerable contortions. Berossos dated the period before the Flood to 120 saroi (3,600 year periods), giving an estimate of 432,000 years before the Flood. This was unacceptable to later Christian commentators, so it was assumed he meant solar days. 432,000 divided by 365 days gives a rough figure of 1,183½ years before the Flood.
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Artist's conception of MER rovers on Mars NASA's Mars Exploration Rover (MER) mission was a robotic space mission involving two Mars rovers, Spirit and Opportunity exploring the planet Mars. It began in 2003 with the launch of the two rovers to explore the Martian surface and geology; both landed on Mars at separate locations in January 2004. Both rovers far outlived their planned missions of 90 Martian solar days: MER-A Spirit was active until March 22, 2010, while MER-B Opportunity was active until June 10, 2018 and holds the record for the longest distance driven by any off-Earth wheeled vehicle.
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Viking 1 was the first of two spacecraft (along with Viking 2) sent to Mars as part of NASA's Viking program. On July 20, 1976, it became the second spacecraft to soft-land on Mars, and the first to successfully perform its mission. (The first spacecraft to soft-land on Mars was the Soviet Union's Mars 3 on December 2, 1971, which stopped transmitting after 14.5 seconds.) Viking 1 held the record for the longest Mars surface mission of days (over 6 years) or Martian solar days, until that record was broken by the Opportunity rover on May 19, 2010.
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The 583.92-day interval between successive close approaches of Venus to Earth is equal to 5.001444 Venusian solar days, making approximately the same face visible from Earth at each close approach. Whether this relationship arose by chance or is the result of some kind of tidal locking with Earth is unknown. The exoplanet Proxima Centauri b, discovered in 2016 that orbits around Proxima Centauri, is tidally locked, expressing either synchronized rotation or a 3:2 spin–orbit resonance like that of Mercury. One form of hypothetical tidally locked exoplanets are eyeball planets, which in turn are divided into "hot" and "cold" eyeball planets.
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There was, then, no single period ascertainable through observations of the solar surface. By equatorial spots the circuit was found to be performed in about two and a half days less than by spots at the (ordinarily) extreme north and south limits of 45°. The assumed ‘mean period’ of 25.38 solar days applied, in fact, only to two zones 14° from the equator; nearer to it the time of rotation was shorter, further from it longer, than the average. Carrington succeeded in representing the daily movement of a spot in any heliographical latitude l, by the empirical expression 865′ ± 165 .
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During the Middle Ages and Renaissance a number of progressively better tables were published that allowed computation of the positions of the Sun, Moon and planets relative to the fixed stars. An important application of these tables was the reform of the calendar. The Alfonsine Tables, published in 1252, were based on the theories of Ptolemy and were revised and updated after the original publication; the most recent update in 1978 was by the French National Centre for Scientific Research. The length of the tropical year was given as 365 solar days 5 hours 49 minutes 16 seconds (≈ 365.24255 days). This length was used in devising the Gregorian calendar of 1582 .
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UTC is within about one second of mean solar time at 0° longitude, so that, because the mean solar day is slightly longer than 86,400 SI seconds, occasionally the last minute of a UTC day is adjusted to have 61 seconds. The extra second is called a leap second. It accounts for the grand total of the extra length (about 2 milliseconds each) of all the mean solar days since the previous leap second. The last minute of a UTC day is permitted to contain 59 seconds to cover the remote possibility of the Earth rotating faster, but that has not yet been necessary.
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The Pale Blue Dot photo taken in 1990 by the Voyager 1 spacecraft showing Earth (center right) from nearly away, about 5.6 hours at light speed. Earth orbits the Sun at an average distance of about every 365.2564 mean solar days, or one sidereal year. This gives an apparent movement of the Sun eastward with respect to the stars at a rate of about 1°/day, which is one apparent Sun or Moon diameter every 12 hours. Due to this motion, on average it takes 24 hours—a solar day—for Earth to complete a full rotation about its axis so that the Sun returns to the meridian.
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Mainly due to tidal effects, the Earth's rotational period is not constant, resulting in minor variations for both solar days and stellar "days". The Earth's day has increased in length over time due to tides raised by the Moon which slow Earth's rotation. Because of the way the second is defined, the mean length of a day is now about 86, 400.002 seconds, and is increasing by about 1.7 milliseconds per century (an average over the last 2, 700 years). The length of a day circa 620 million years ago has been estimated from rhythmites (alternating layers in sandstone) as having been about 21.9 hours.
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Tidal deceleration rates have varied over the history of the Earth-Moon system. Analysis of layering in fossil mollusc shells from 70 million years ago, in the Late Cretaceous period, shows that there were 372 days a year, and thus that the day was about 23.5 hours long then. Based on geological studies of tidal rhythmites, the day was 21.9±0.4 hours long 620 million years ago and there were 13.1±0.1 synodic months/year and 400±7 solar days/year. The average recession rate of the Moon between then and now has been 2.17±0.31 cm/year, which is about half the present rate.
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This geological record is consistent with these conditions 620 million years ago: the day was 21.9±0.4 hours, and there were 13.1±0.1 synodic months/year and 400±7 solar days/year. The average recession rate of the Moon between then and now has been 2.17±0.31 cm/year, which is about half the present rate. The present high rate may be due to near resonance between natural ocean frequencies and tidal frequencies. Analysis of layering in fossil mollusc shells from 70 million years ago, in the Late Cretaceous period, shows that there were 372 days a year, and thus that the day was about 23.5 hours long then.
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632 note At least one mathematical astronomer adopted Herschel's "days of the Julian period" immediately. Benjamin Peirce of Harvard University used over 2,800 Julian days in his Tables of the Moon, begun in 1849 but not published until 1853, to calculate the lunar ephemerides in the new American Ephemeris and Nautical Almanac from 1855 to 1888. The days are specified for "Washington mean noon", with Greenwich defined as west of Washington (282°57′W, or Washington 77°3′W of Greenwich). A table with 197 Julian days ("Date in Mean Solar Days", one per century mostly) was included for the years –4713 to 2000 with no year 0, thus "–" means BC, including decimal fractions for hours, minutes and seconds.
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In contrast, in regions such as Kerala, the solar cycle is emphasized and this is called the Malayalam calendar, their new year starts in autumn, and these have origins in the second half of the 1st millennium CE. A Hindu calendar is sometimes referred to as Panchanga (पञ्चाङ्ग). The ancient Hindu calendar conceptual design is also found in the Jewish calendar, but different from the Gregorian calendar. Unlike the Gregorian calendar which adds additional days to the lunar month to adjust for the mismatch between twelve lunar cycles (354 lunar days), Quote: "the lunar year consists of 354 days". and nearly 365 solar days, the Hindu calendar maintains the integrity of the lunar month, but inserts an extra full month by complex rules, once every 32–33 months, to ensure that the festivals and crop- related rituals fall in the appropriate season.
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Of the eight solar planets, all but Venus and Uranus have prograde rotation—that is, they rotate more than once per year in the same direction as they orbit the Sun, so the Sun rises in the east. Venus and Uranus, however, have retrograde rotation. For prograde rotation, the formula relating the lengths of the sidereal and solar days is: or, equivalently: On the other hand, the formula in the case of retrograde rotation is: or, equivalently: All the solar planets more distant from the Sun than Earth are similar to Earth in that, since they experience many rotations per revolution around the Sun, there is only a small difference between the length of the sidereal day and that of the solar day – the ratio of the former to the latter never being less than Earth's ratio of 0.997. But the situation is quite different for Mercury and Venus.
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Like the Gregorian calendar, the Vikram Samvat reconciles a solar year with lunar months, but it resembles the Hebrew calendar in its handling of the lunar- solar discrepancy. Unlike the Gregorian calendar, which adds days to the lunar month to adjust for the mismatch between twelve lunar cycles (354 lunar days), Text: "...the lunar year consists of 354 days..." and nearly 365 solar days, the Vikram Samvat and Hebrew calendars maintain the integrity of the lunar month; an extra month 'appears', on a strict scientific basis, roughly once every three years (or 7 times in a 19-year cycle, to be more exact) to ensure that festivals and crop-related rituals fall in the appropriate season. The extra month appears in Chinese and Jewish calendars as well; in India it is called adhik maas. The Vikram Samvat is one of the lunisolar calendars developed by ancient human cultures.
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The Julian calendar has two types of year: "normal" years of 365 days and "leap" years of 366 days. There is a simple cycle of three "normal" years followed by a leap year and this pattern repeats forever without exception. The Julian year is, therefore, on average 365.25 days long. Consequently, the Julian year drifts over time with respect to the tropical (solar) year (365.24217 days).Using value from Richards (2013, p. 587) for tropical year in mean solar days, the calculation is Although Greek astronomers had known, at least since Hipparchus,Claudius Ptolemy, tr. G. J. Toomer, Ptolemy's Almagest, 1998, Princeton University Press, p. 139. Hipparchus stated that the "solar year ... contains 365 days, plus a fraction which is less than by about th of the sum of one day and night". a century before the Julian reform, that the tropical year was slightly shorter than 365.25 days, the calendar did not compensate for this difference.
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Gauss' constant is derived from the application of Kepler's third law to the system of Earth+Moon and the Sun considered as a two body problem, relating the period of revolution () to the major semi-axis of the orbit () and the total mass of the orbiting bodies (). Its numerical value was obtained by setting the major semi-axis and the mass of the Sun to unity and measuring the period in mean solar days: : 2 / ( ) ≈ 0.0172021 [rad], where: : ≈ 365.256 [days], = (++) ≈ 1.00000304 [], and = 1 by definition. The value represents the mean angular motion of the Earth-Sun system, in radians per day, equivalent to a value just below one degree (the division of the circle into 360 degrees in Babylonian astronomy was likely intended as approximating the number of days in a solar yearDavid H. Kelley, Eugene F. Milone, Exploring Ancient Skies: A Survey of Ancient and Cultural Astronomy (2011), p. 219). The correction due to the division by the square root of reflects the fact that the Earth–Moon system is not orbiting the Sun itself, but the center of mass of the system.
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