Earth's moon could have formed in just 5 hours after giant impact

The moon could have formed in a matter of hours following the giant impact between Earth and a Mars-size protoplanet early in the history of the solar system. The theory comes from new simulations that take into account how the internal temperature of young protoplanets affected their geologic properties and therefore the collisions they experienced.

This giant impact scenario has become the leading theory of how the moon formed, thanks in particular to work done by planetary scientist Robin Canup. Since 2001, she has conducted and refined numerous computer simulations that describe how a Mars-size body called Theia collided at an angle just right to throw debris into orbit around the proto-Earth.

Now other researchers are getting in on the act. Adeene Denton of the South-west Research Institute led a team who performed some of the most detailed simulations of the collision yet, taking into account more of the geologic properties of the colliding wo...