In studying the surfaces of solid bodies in the solar system, astronomers have learned that the number of craters (per unit area):
A) is about the same on every world
B) is greater as you get closer to the Sun
C) is greater as you get further and further from the Sun
D) is roughly proportional to the age of the surface we are examining
E) follows no discernible rules or relationships at all

Question

Quizplus · Accepted Answer

Craters on solid bodies in the solar system are caused by impacts with other objects. As such, the number of craters on a surface can give an indication of its age: the more craters, the older the surface. Therefore, the number of craters is roughly proportional to the age of the surface we are examining.

In Studying the Surfaces of Solid Bodies in the Solar