An apparent westward motion of a planet from night to night compared to the background stars (as viewed from Earth) is referred to as
A) retrograde motion.
B) precession.
C) rising (if in the east) or setting (if in the west).
D) direct motion.

Question

Quizplus · Accepted Answer

Retrograde motion is the apparent westward drift of a planet against the background stars as observed from Earth. This occurs when Earth, on its faster orbit, overtakes an outer planet, making the outer planet appear to move backward in the sky.

An Apparent Westward Motion of a Planet from Night to Night