Question

What causes the apparent retrograde motion of Mars?

A. Mars orbits the Sun in the opposite direction as Earth.
B. Because Earth orbits faster than Mars, Mars always seems to move in the opposite direction as the Moon and the Sun.
C. When Earth passes Mars, it appears to change its motion relative to the background stars.
D. Mars reverses its orbital motion when it is furthest from the Sun

Answer 1

The apparent retrograde motion of Mars is caused by Earth's faster orbital speed and the positioning of Earth and Mars in their respective orbits around the Sun.

Step-by-step explanation:

The apparent retrograde motion of Mars is caused by the combination of Earth's faster orbital speed and the positioning of Earth and Mars in their respective orbits around the Sun. Although Mars orbits the Sun in the same direction as Earth, its slower orbital speed causes it to be overtaken by Earth periodically, resulting in the illusion of backward motion.

During these periods, Earth appears to move past Mars, causing Mars to appear to move in the opposite direction. This is similar to two cars racing on a track, where the faster-moving car passes the slower-moving car, giving the impression of the slower car moving backward.

Therefore, option B is the correct answer: Because Earth orbits faster than Mars, Mars always seems to move in the opposite direction as the Moon and the Sun.