Precession of equinoxes
Standish, E. Myles Formerly, Jet Propulsion Laboratory, National Aeronautics and Space Administration, Pasadena, California.
Harrington, Robert S. Formerly, U.S. Naval Observatory, Washington, DC.
Last reviewed:December 2019
- Earth's axis
- Earth's orbit
- Related Primary Literature
- Additional Reading
A slow change in the direction of the axis of rotation of the Earth and also a very small change in the orientation of the Earth's orbit around the Sun. Thus, both the celestial equator (the projection of the terrestrial equator onto the sky) and the ecliptic (the projection of the Earth's orbit onto the sky) move slowly in time, and, consequently, so do their intersections, the vernal and autumnal equinoxes. See also: Celestial sphere; Ecliptic; Equator; Equinox
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