Simulations of a collision between proto-Earth and a protoplanet called Theia suggest that the moon may have formed as a result of this impact. The exact nature of the collision is unclear, with some simulations indicating a single impact and others proposing a series of impacts, possibly involving multiple collisions. Supercomputer simulations are being used to study the formation of the moon and the early solar system, which appears to have been a violent and destructive process.