The theory of how the moon formed, most of the scientists agree with, is the one suggesting that about 4.56 billion years ago, a mysterious planet the size of Mars crashed into Earth. The slam event supposedly happened just after the solar system was formed.
The new studies however, suggest that the moon is in fact between 4.4 billion and 4.45 billion years old. How did the scientists came to this new theory you ask? They did new analyses of the lunar rocks, which resulted in a the newest believe, that our closest neighbor in space is in fact 100 million years younger that previously believed.