Evolution of the Moon

At this point, we're pretty sure that our Moon, which is an unusually large one in our Solar System, was formed when a Mars-sized body crashed into the Earth about 4.5 billion years ago, during the formation of the Solar System. NASA has made this amazing video to show how our lovely companion went from the ball of magma 4.5 billion years ago to the "finished" product we see in the sky today. Make sure to full-screen and watch in HD!