ESS101C
Prof.
Jin-Yi Yu
Precession of Axis
qThere are two kinds of
precession: (1) the precession of the spin axis and (2) the precession of the
ellipse.
qEarth’s wobbling motion is
called the axial
precession. It is caused by the gravitational pull of the Sun
and Moon.
qAxial
precession is a slow turning of Earth’s axis of rotation through a circular path, with a full turn
every 25,700
years.
(from Earth’s Climate: Past and Future)