During the time that a planet is in its period of apparent retrograde motion,
A)the planet moves backwards (clockwise as viewed from above Earth's north pole)in its orbit of the Sun.
B)the planet appears to rise in the west and set in the east,rather than the usual rising in the east and setting in the west.
C)over many days or weeks,the planet moves westward relative to the stars,rather than the usual eastward relative to the stars.
D)the planet is getting closer to the Sun in its orbit.

Question

Quizplus · Accepted Answer

During a planet's period of retrograde motion, it appears to move westward relative to the stars, which is opposite to its normal eastward motion relative to the stars. This is caused by the difference in orbital speeds between the Earth and the planet, making it appear as if the planet is moving backward in its orbit while Earth "overtakes" it.

During the Time That a Planet Is in Its Period