Retrograde motion (east to west among the stars) is observed
A) for some planets as Earth passes between that planet and the sun.
B) for the sun during the entire year.
C) for Earth's moon during an entire month.
D) none of the above.

Question

Quizplus · Accepted Answer

Retrograde motion is observed when planets appear to move backwards in their normal motion among the stars. This occurs because of the difference in the orbital speed and distance of the planets from Earth. As Earth passes between a planet and the sun, the planet appears to move backwards (retrograde motion) against the background of stars.

Retrograde Motion (East to West Among the Stars) Is Observed