anomalistic year, time required for the earth to go from the perihelion point once around the sun and back to the perihelion point. It is 365 days, 6 hr, 13 min, 53.0 sec of mean solar time (see solar time). The anomalistic year is longer than the sidereal year and the tropical year because of the eastward motion of the line of apsides (see apsis), which is caused by the slow rotation of the earth's orbit as a whole.