The Moon probably formed
A) out of a collision between the Earth and a Mars-sized object.
B) when the Earth's gravity captured a planetesimal.
C) when the accretion disk around the Earth fragmented.
D) when planetesimals collided to form a more massive object.

Question

Quizplus · Accepted Answer

The prevailing theory for the formation of the Moon is the Giant Impact Hypothesis, which suggests that a Mars-sized object collided with the Earth about 4.5 billion years ago. The collision sent debris into space, which eventually coalesced to form the Moon.

The Moon Probably Formed