sidereal years definition of sidereal years in the Free Online Encyclopedia.

sidereal year, time required for the earth to complete an orbit of the sun relative to the stars. The sidereal year is 365 days, 6 hr, 9 min, 9.5 sec of mean solar time (see solar time solar time, time defined by the position of the sun. The solar day is the time it takes for the sun to return to the same meridian in the sky. Local solar time is measured by a sundial .
..... Click the link for more information. ). It is 20 min longer than the tropical year tropical year, time between successive vernal equinoxes ; 365 days, 5 hr, 48 min, 46 sec of mean solar time (see solar time ). The tropical year is the basis of the year used in the Gregorian calendar .
..... Click the link for more information. because of the precession of the equinoxes precession of the equinoxes, westward motion of the equinoxes along the ecliptic . This motion was first noted by Hipparchus c.120 B.C. The precession is due to the gravitational attraction of the moon and sun on the equatorial bulge of the earth, which causes the
..... Click the link for more information. ; for this reason, the sidereal year does not stay in step with the seasons.

sidereal year [sī′dir·ē·əl ′yir]

(astronomy)

The time period relative to the stars of one revolution of the earth around the sun; it is about 365.2564 mean solar days.

sidereal year (redirected from sidereal years)

sidereal year
(redirected from sidereal years)