"sidereal year." YourDictionary, n.d. Web. 26 May 2018. <http://www.yourdictionary.com/sidereal-year>.
sidereal year. (n.d.). Retrieved May 26th, 2018, from http://www.yourdictionary.com/sidereal-year
(plural sidereal years)
The orbitalperiod of the Earth; a measure of the time it takes for the Sun to return to the same position with respect to the stars of the celestial sphere. A sidereal year is about 20.4 minutes longer than the tropical year due to precession of the equinoxes.
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