The phenomenon of precession of Earth's spin axis is caused by the
A) variation of the spin rate of Earth.
B) tidal ebb and flow of ocean waters on Earth.
C) varying intensity and hence pressure of sunlight on Earth throughout the year.
D) gravitational pull of Moon and Sun on Earth's equatorial bulge.

Question

Quizplus · Accepted Answer

The precession of Earth's spin axis, a slow wobble that alters the orientation of Earth's axis of rotation, is primarily caused by the gravitational pull exerted by the Moon and the Sun on Earth's equatorial bulge. This gravitational force causes the rotational axis to process over a period of approximately 26,000 years.

The Phenomenon of Precession of Earth's Spin Axis Is Caused