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precession
subject			fact

precession	has rate
	has definition The slow (once per twenty-six thousand years) gyration of the Earth's axis.
	has definition A slow, periodic conical motion of the rotation axis of a spinning body. In the case of Earth's precession it is due to the fact that Earth's axis of rotation is not perpendicular to the ecliptic but is inclined about 23°.5 and is thus affected by gravitational perturbations from other bodies in the solar system. The Moon and Sun pull harder on that part of the Earth's equatorial bulge nearest them than on that farthest away; this causes a torque which precesses the Earth's rotational axis.
	has definition The uniformly progressing motion of the pole of rotation of a freely rotating body undergoing torque from external gravitational forces. In the case of the Earth, the component of precession caused by the Sun and Moon acting on the Earth's equatorial bulge is called lunisolar precession; the component caused by the action of the planets is called planetary precession. The sum of lunisolar and planetary precession is called general precession. (See nutation.)
	is a kind of axis motion
physical process	has domain physics

Kinds of precession :

• apsidal motion (2 facts) - Rotation of the line of apsides in the plane of the orbit; (in a binary) precession of the line of apsides due to mutual tidal distortion.
• general precession (3 facts) - The sum of the lunisolar and the planetary precession. It causes the ecliptic longitude to increase at a constant rate but has no effect on ecliptic latitude.
• geodetic precession (3 facts) - A small, relativistic, direct motion of the equinox along the ecliptic.
• Lense-Thirring effect (2 facts) - The precession of the plane of the geodesic orbit of a test particle around a rotating mass in general relativity. It arises from the coupling of the rotation of the central mass with the orbital angular momentum of the test particle. This precession is described as resulting from the dragging of inertial frames.
• planetary precession (3 facts) - The component of general precession caused by the gravitational coupling between the center of mass of the Earth and that of the other planets. The effect of planetary precession is to move the equinox eastward by ≈ 0".11 / year and to diminish the angle between the ecliptic and the equator by about 0".47 / year.
• vector translation (3 facts) - The small theoretical precession of the axis of an orbiting body due to the gravitational influence of its primary. This effect is predicted by general relativity, but so far it has not been observed.