- nutation by Michelle Obrien
In astronomy, a slight wobbling motion of the earth's axis. The causes of nutation are similar to those of the precession of the equinoxes, involving the varying attraction of the moon on the earth's equatorial bulge. However, the period of the motion is only 18.6 years, the same as that of the precession of the moon's nodes, as opposed to the nearly 26,000 ...
- precession of the equinoxes by Shane Coleman
... of 26,000 years, caused by the attractive force of the sun, moon, and other planets on the equatorial protuberance of the earth; it results in a gradual westward motion of the equinoxes.
- whirly by Cassidy Johnson
... meteorology) A small violent storm, a few yards (or meters) to 100 yards (91 meters) or more in diameter, frequent in Antarctica near the time of the equinoxes.
- Hipparchus by Brooklyn Hopkins
... fl. 146–127 B.C.) astronomer who calculated the year and discovered the precession of the equinoxes. [Turkish Hist.: EB, V: 55] See: Astronomy
- Precessional by Webster's
... a.) Of or pertaining to pression; as, the precessional movement of the equinoxes.