单词 | sidereal year |
释义 | sidereal yearnoun Astronomy The orbital period of the earth around the sun, taking the stars as a reference frame. It is 20 minutes longer than the tropical year because of precession.Because of the precession of the equinoxes the tropical year is shorter by about 21 minutes than the sidereal year (the time taken by the Sun to return to the same place against the background stars)....
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