The direction of retrograde motion for a planet as seen by an observer on Earth is
A) west to east relative to the background stars.
B) east to west relative to the background stars.
C) east to west relative to objects on the person's horizon.
D) west to east relative to objects on the person's horizon.

Question

Quizplus · Accepted Answer

Retrograde motion is observed when a planet appears to move east to west relative to the background stars, opposite to the normal west to east motion. This apparent reversal happens due to the relative positions and motions of Earth and the other planet in their orbits around the Sun.

The Direction of Retrograde Motion for a Planet as Seen