Anomalous year
The anomalous year is the time interval between two passes of the earth through its perihelion , i.e. the mean orbit period of the earth.
January 1, 2000 ( epoch J2000.0 ) is used as a reference for the duration of the anomalous year . The anomalistic year at this point was
- 31558432.539 seconds , which corresponds to 365.25963588 sunny days = 365 days, 6 hours , 13 minutes and 52.539 seconds.
The earth's orbit around the sun is (slightly) elliptical , but the position of the orbital ellipse in the plane of the orbit is not constant; the influence of the gravitation of the other planets causes the apsidal rotation . The direction of rotation of the apsidal line of the orbit ellipse is the same as the direction of rotation of the earth on this ellipse, perihelion (currently on January 3rd; the exact date fluctuates by plus / minus two days due to leap year effects and the influence of the moon ) and aphelion ( currently around July 4th) are turning away from the approaching earth. The anomalistic year is therefore slightly longer than the sidereal year , the duration of an earth orbit in spatially fixed coordinates. Since the earth's orbit ellipse has the same position in space again after about 112,000 years (this period of a complete revolution of the apsidal line is called the cycle of the perihelion of the earth ), an anomalous year is on average around longer than a sidereal year, which corresponds to a good 4 Minutes and 40 seconds.
