Is there geological evidence that the moon once collided with the Earth?

Question

I've seen models in astronomy that show how the Earth-Moon system must have come together after a collision. However, I have not heard whether there is any actual physical evidence on Earth that points to a prior collision. Is there geological (or other physical) evidence here on Earth that confirms the moon originated from a collision on Earth? If so what is that evidence?

Answer 1

There are some intriguing geochemical studies from mantle rock that hint at this, but the best evidence actually isn't on Earth - it's on the moon!

The rocks we have brought back from the moon are basically a hybrid composition of Earth's mantle and the impactor, and so they support the collision model.