During the period each year when we see Mars undergoing apparent retrograde motion in our sky, what is really going on in space?
A)Earth and Mars are on opposite sides of the Sun.
B)Mars is moving around the Sun in the opposite direction from which Earth is moving around the Sun.
C)Earth is catching up with and passing by Mars in their respective orbits.
D)Earth and Mars are getting closer together.

Question

Quizplus · Accepted Answer

Apparent retrograde motion occurs when Earth, in its faster orbit around the Sun, overtakes and passes by Mars, causing it to appear to move backwards (westward) in the sky before resuming its normal eastward motion. This happens because of the difference in the speed and distance of the orbits of Earth and Mars around the Sun.

During the Period Each Year When We See Mars Undergoing