# Do we know what Earth looked like before the collision with Theia?

Let's assume the moon was formed because Earth collided into Theia. (There are numerous other theories, but this one is the most widely accepted.)

In that case, do we know what the Earth surface looked like? E.g. Did Earth have bodies of water? (I've read some websites and a book!, and some say it did, some say it did not).

• I would suggest, but I'm not an expert in such things, that Earth was so young when the impact happened that it still had considerable surface heat due to formation and frequent impacts. Some estimates put Earth at as young as 30 million years when the giant impact happened. I imagine it had water and an atmosphere, but I'd only be making guesses as to how much. – userLTK Feb 12 at 12:40