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astronomical and constant
In 1976 the International Astronomical Union ( IAU ) revised the definition of the AU for greater precision, defining it as that length for which the Gaussian gravitational constant ( k ) takes the value when the units of measurement are the astronomical units of length, mass and time.
With the definitions used before 2012, the astronomical unit was dependent on the heliocentric gravitational constant, that is the product of the gravitational constant G and the solar mass M < sub >☉</ sub >.
The solar constant, a measure of flux density, is the amount of incoming solar electromagnetic radiation per unit area that would be incident on a plane perpendicular to the rays, at a distance of one astronomical unit ( AU ) ( roughly the mean distance from the Sun to the Earth ).
The start of an astronomical winter remains constant in each hemisphere regardless of weather conditions, but varies with culture.
The quantity GM — the product of the gravitational constant and the mass of a given astronomical body such as the Sun or the Earth — is known as the standard gravitational parameter and is denoted.
This is a key requirement for a complete interpretation of astronomical observations, particularly pertaining to the nature of dark energy and the cosmological constant.
The orbital radius at which the stellar flux from Epsilon Eridani matches the solar constant — where the emission matches the Sun's output at the orbital distance of the Earth — is 0. 61 astronomical units ( AU ).
Based upon the length of the year, the distance from the Earth to the Sun ( an astronomical unit or AU ), and the gravitational constant ( G ), the mass of the Sun is given by:
) Otherwise, the time-varying astronomical quantity can be expressed by a constant, equal to the measure that it had at the epoch, leaving the law of its variation according to time interval from the epoch to be specified in some other way — for example, by a table, as was common practice during the 17th and 18th centuries.
where A is the unit distance ( the value of the astronomical unit in metres ) and k is a constant ( whose value is very close to one ) that reflects the fact that the mean distance from the Earth to the Sun is not exactly one astronomical unit.
The Gaussian gravitational constant ( symbol k ) is an astronomical constant first proposed by German polymath Carl Friedrich Gauss in his 1809 work Theoria motus corporum coelestium in sectionibus conicis solem ambientum (" Theory of Motion of the Celestial Bodies Moving in Conic Sections around the Sun "), although he had already used the concept to great success in predicting the orbit of Ceres in 1801.
It formed the basis of the definition of the international second from 1956 to 1967, and has been a defining constant in the astronomical system of units since 1952.
The Gaussian gravitational constant is now an IAU defining constant used to define the astronomical unit.
The value of the astronomical unit is no longer defined as the semi-major axis of the Earth's orbit, but instead that length which give exactly Gauss ' original value of the gravitational constant.
The solar constant, a measure of flux density, is the amount of incoming solar electromagnetic radiation per unit area that would be incident on a plane perpendicular to the rays, at a distance of one astronomical unit ( AU ) ( roughly the mean distance from the Sun to the Earth ).
When it became apparent that the universe is not static, but expanding, Einstein was quick to discard this additional term ; prematurely, as we know today: From about 1998 on, a steadily accumulating body of astronomical evidence has shown that the expansion of the universe is accelerating in a way that suggests the presence of a cosmological constant or, equivalently, of a dark energy with specific properties that pervades all of space.
This solution has not been especially useful for describing astrophysical phenomena, because observed astronomical objects do not possess an appreciable net electric charge, and the cosmological constant is now thought to be non-zero.
* Solar constant, the amount of solar electromagnetic radiation per square unit area at a distance of one astronomical unit from the Sun
An astronomical constant is a physical constant used in astronomy.

astronomical and whose
Robert Hooke, in 1674, published his observations of γ Draconis, a star of magnitude 2 < sup > m </ sup > which passes practically overhead at the latitude of London, and whose observations are therefore free from the complex corrections due to astronomical refraction, and concluded that this star was 23 ″ more northerly in July than in October.
He associated himself with local gentlemen interested in astronomy, including William Litchford, whose library included the work of the astrologer John Gadbury which included astronomical tables by Jeremiah Horrocks, who had died in 1641 at the age of twenty-three.
Some of Eudoxus ' astronomical texts whose names have survived include:
Hyades binaries tend to have small separations, with most binary pairs in shared orbits whose semimajor axes are smaller than 50 astronomical units.
Milanković also studied the works of Joseph Adhemar and James Croll, whose pioneering theories on the astronomical origins of ice ages were formally rejected by their contemporaries.
If his writing is often seen as trying to popularize the astronomical theories of René Descartes, whose greatest exponent he is sometimes considered, it also appealed to the literate society of the day to become more involved in " natural philosophy ," thus enriching the work of early-Enlightenment scientists.
I confirm this view not only by refuting Ptolemy's and Aristotle's arguments, but also by producing many for the other side, especially some pertaining to physical effects whose causes perhaps cannot be determined in any other way, and other astronomical discoveries ; these discoveries clearly confute the Ptolemaic system, and they agree admirably with this other position and confirm it.
According to Edward Moore of St. Elias School of Orthodox Theology, Nebraska, Apokatastasis was first properly conceptualized in early Stoic thought, particularly by Chrysippus whose thinking was influenced by the theory of recurrence and cosmic cycles in Babylonian astronomical thought.
Richard Christopher Carrington ( 26 May 1826 – 27 November 1875 ) was an English amateur astronomer whose 1859 astronomical observations demonstrated the existence of solar flares as well as suggesting their electrical influence upon the Earth and its aurorae ; and whose 1863 records of sunspot observations revealed the differential rotation of the Sun.
Beatrice Muriel Hill Tinsley ( 27 January 1941 – 23 March 1981 ) was a New Zealand astronomer and cosmologist whose research made fundamental contributions to the astronomical understanding of how galaxies evolve with time.
In the summer of 1886, under the sponsorship of the Spanish Society of Commercial Geography (), Julio Cervera Baviera, Felipe Rizzo ( 1823 – 1908 ), and Francisco Quiroga ( 1853 – 1894 ) traversed the colony of Rio de Oro, where they made topographical and astronomical observations in a land whose features were barely known at the time to geographers.
Some are serious enough to be considered problematic ( for example ; 1. none of the astronomical observations have dates that mention the specific pharaoh in whose reign they were observed, forcing Egyptologists supply that information on the basis of a certain amount of informed speculation, 2. there is no information regarding the nature of the civil calendar throughout the course of Egyptian history, forcing Egyptologists to assume that it existed unchanged for thousands of years ), other criticisms are not considered as problematic ( for example ; there is no extant mention of the Sothic cycle in ancient Egyptian writing, which may simply be a result of it either being so obvious to Egyptians that it didn't merit mention or to relevant texts being destroyed over time or still awaiting discovery ).
The wooden bell-striker, which has been replaced several times, has been a fixture of the Zytglogge since the renewal of the astronomical clock in 1530, whose clockwork also controls the figure's motions.
Burroughs vision of Mars was loosely inspired by astronomical speculation of the time, especially that of Percival Lowell, who saw the planet as a formerly Earthlike world now becoming less hospitable to life due to its advanced age, whose inhabitants had built canals to bring water from the polar caps to irrigate the remaining arable land.
| 9325 Stonehenge || || Stonehenge, prehistoric megalithic complex, whose design relies on astronomical observation in great part
Schedar is an orange giant star whose spectral classification in the SIMBAD astronomical database is listed as K0IIIa, a stellar class that is notably cooler than the Sun.
The fact that the chronicler or chroniclers did not realise that they had seen a planet rather than a new star demonstrates the weak astronomical knowledge of the scholars of the time, whose astronomical accounts are actually very difficult to interpret and attribute to a rare event.
Depending on the brightness of the stars and their astronomical or symbolic importance, they were more or less well described by the Chinese astronomers, only a part of whose literature has come down to the present day.
Burroughs's vision of Mars was loosely inspired by astronomical speculation of the time, especially that of Percival Lowell, who saw the planet as a formerly Earthlike world now becoming less hospitable to life due to its advanced age, whose inhabitants had built canals to bring water from the polar caps to irrigate the remaining arable land.

astronomical and value
This value of the astronomical unit had to be obtained experimentally and so is was not known exactly.
The comparison of the ephemeris with the measured positions leads to a value for the speed of light in astronomical units, which is AU / d ( TDB ).
As the speed of light in meters per second ( c < sub > 0 </ sub >) is fixed in the International System of Units, this measurement of the speed of light in AU / d ( c < sub > AU </ sub >) also determines the value of the astronomical unit in meters ( A ):
The best current ( 2009 ) estimate of the International Astronomical Union ( IAU ) for the value of the astronomical unit in meters is A = m, based on a comparison of JPL and IAA – RAS ephemerides.
Another " ordinal " date system (" ordinal " in the sense of advancing in value by one as the date advances by one day ) is in common use in astronomical calculations and referencing and uses the same name as this " logistics " system.
In fact, even if all estimates have astronomical absolute values for their errors, if the expected value of the error is zero, the estimator is unbiased.
All years in the BC era must be converted to a negative value then incremented toward zero to be passed as an astronomical year, so that 1 BC will be passed as year 0.
Improved estimates of Venus ' mass and the value of the astronomical unit were made.
The value of the astronomical unit in light seconds is a fundamental measurement for the calculation of modern ephemerides ( tables of plantary positions ): it is usually quoted as " light-time for unit distance " in tables of astronomical constants, and its currently accepted value is s.
Much of the loss in value of the acquired companies was put down to the astronomical " goodwill " payment included in the purchase price during the " dotcom boom ".
The Ascendant, from an astronomical point of view, is the value of the ecliptical geocentric longitude ( aka Celestial Longitude λ ) of the point of the ecliptic which is easterly on the horizon.
Radar techniques provide information unavailable by other means, such as testing general relativity by observing Mercury and providing a refined value for the astronomical unit.
This was a target of great scientific value, since it could provide an unambiguous way to measure the size of the astronomical unit, which was needed for the nascent field of interplanetary spacecraft.
The value that was calculated by Gauss, in the astronomical system of units, is still used today.
The astronomical system of units was redefined in 1976 to fix the value of k at precisely.

0.446 seconds.