Tropical Year

A tropical year (also known as a solar year), for general purposes, is the length of time that the Sun takes to return to the same position in the cycle of seasons, as seen from Earth; for example, the time from vernal equinox to vernal equinox, or from summer solstice to summer solstice. Because of the precession of the equinoxes, the seasonal cycle does not remain exactly synchronized with the position of the Earth in its orbit around the Sun. As a consequence, the tropical year is about 20 minutes shorter than the time it takes Earth to complete one full orbit around the Sun as measured with respect to the fixed stars (the sidereal year).

Since antiquity, astronomers have progressively refined the definition of the tropical year, and currently define it as the time required for the mean Sun's tropical longitude (longitudinal position along the ecliptic relative to its position at the vernal equinox) to increase by 360 degrees (that is, to complete one full seasonal circuit). (Meeus & Savoie, 1992, p. 40)

Read more about Tropical Year:  Time Scales, Length of Tropical Year, Calendar Year

Other articles related to "years, year, tropical year":

Axial Precession - Hipparchus' Discovery
3rd century BC), he found that Spica's longitude had decreased by about 2° in about 150 years ... also studied precession in On the Length of the Year ... Two kinds of year are relevant to understanding his work ...
Johann Heinrich Von Mädler - The Conventional Tropical Year According To Von Mädler
... important works, von Mädler made calculations concerning the true length of the tropical year with precision never attained before, though this fact is little known ... on his results, he proposed to Russia, which at this time used the conventional tropic year according to Sosigenes of Alexandria of exactly 365 days 6 hours (cf ... to equal Gregorian Calendar dates in the year 1900, but then, first proposed by von Mädler himself, a new 128-year rule for additional common years ...
Tropical Year - Calendar Year
... calendar, meaning that it is designed to maintain synchrony with the tropical year ... It has a cycle of 400 years (146,097 days) ... The average year length is 146,097/400 = 365+97/400 = 365.2425 days per year, a close approximation to the tropical year ...
Astronomical Years - Sidereal, Tropical, and Anomalistic Years
... Each of these three years can be loosely called an 'astronomical year' ... The sidereal year is the time taken for the Earth to complete one revolution of its orbit, as measured against a fixed frame of reference (such as the fixed stars, Latin sidera, singular sidus) ... The tropical year is the period of time for the ecliptic longitude of the Sun to increase by 360 degrees ...
MLY - Numerical Value - Other Values
... Before 1984, the tropical year (not the Julian year) and a measured (not defined) speed of light were included in the IAU (1964) System of Astronomical Constants, used from 1968 to 1983 ... The product of Simon Newcomb's J1900.0 mean tropical year of 31556925.9747 ephemeris seconds and a speed of light of 299792.5 km/s produced a light-year of 9.460530×1015 m (rounded to the ... A value of 9.460536207×1015 m found in some modern sources is the product of a mean Gregorian year of 365.2425 days (31556952 s) and the defined ...

Famous quotes containing the words year and/or tropical:

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