When the Earth catches up to a slower moving outer planet and passes it in its orbit like a faster runner overtakes a slower runner in an outside lane,the planet
A) exhibits retrograde motion.
B) slows down because it feels the Earth's gravitational pull.
C) decreases in brightness as it passes through the Earth's shadow.
D) moves into a more elliptical orbit.

Question

Quizplus · Accepted Answer

The planet exhibits retrograde motion as seen from Earth during the time when the Earth passes it in its orbit. This apparent retrograde motion is caused by the difference in orbital speeds between the Earth and the outer planet.

When the Earth Catches Up to a Slower Moving Outer