The reason for the slow drift of the position of the vernal equinox through our sky against the background stars over long periods of time is the:
A) motion of Earth in its orbit.
B) overall movement of local stars in our sky.
C) movement of the Sun in the Milky Way Galaxy.
D) precession of Earth's spin axis.

Question

Quizplus · Accepted Answer

The slow drift of the position of the vernal equinox over long periods of time is caused by the precession of Earth's spin axis. As Earth spins, its axis wobbles like a top, completing a full circle approximately every 26,000 years. This wobble causes the orientation of Earth's axis to slowly change, causing the position of the vernal equinox to appear to move slowly against the background stars over time.

The Reason for the Slow Drift of the Position of the Vernal