Planets and satellites with a large amount of surface cratering generally have insignificant atmospheres. Why are these two conditions correlated?
A)The impacts that create the craters also tend to vaporize the atmosphere.
B)A large amount of cratering implies a small size, and this, in turn, implies a low escape speed.
C)A large amount of cratering implies a small size, and this, in turn, implies a high escape speed.
D)Most of the solar system debris that caused cratering was near the Sun. Thus, heavily cratered planets and satellites are near the Sun where high temperatures result in high average molecular speeds.

Question

Quizplus · Accepted Answer

Planets and satellites with a large amount of surface cratering are generally small in size. Small size implies a low escape speed, which makes it easier for the gases making up the atmosphere to escape into space. Therefore, such bodies are unlikely to retain significant atmospheres. The impacts that create the craters do not tend to vaporize the atmosphere, and the location of the planet or satellite in the solar system does not significantly affect the presence or absence of atmosphere.

Planets and Satellites with a Large Amount of Surface Cratering