Question - Explain the mechanism for the formation of Earth’s moon.

Explain the mechanism for the formation of Earth’s moon.

Answer: 

It is hypothesized that the Earth’s moon formed at around 4.5 Ga, when a Mars-sized planet smashed into the Earth and blasted a moon-sized part of the Earth into orbit around the Earth. That material, which included some of the incoming planet and some of the Earth’s early crust and mantle, eventually coalesced into the moon.