How does precession work?
The primary cause for the precession motion of the polar axis is
gravitational torque ( rotation causing force ) of interactive
attractions from the nearer Luna and the farther Sun, upon the
In this revolutionary motion the polar axis revolves like a double
conical pendulum over a mildly corrugated surface of a double
right cone. The vertex of this cone is near the center of the Earth.
The semi angle of this cone is the Earth's obliquity ( axial tilt angle )
The poles describe small lateral oscillations ( due to nodding (
nutation) ), while moving along a small circle on the surface of the
The period of the precession revolution is great and is befittingly
called Great Year that is nearly 258 centuries.
The incognizant ( not easily perceived ) backward shift of either
equinox on the equator, wherein it is annual right overhead noon,
makes the total for about 258 centuries as 24 hours. This is a work
of this precession
For graphical depiction with animation, see the gyroscopic