A second solution proposes that the moon-forming impact was much more energetic than previously thought, generating a huge cloud of vaporized rock more than 500 times larger than Earth. According to this theory, the vaporized rock was a mixture of the proto-Earth’s mantle and Theia. The Earth’s mantle and atmosphere, and Theia’s material, became a thoroughly mixed and continuous cloud. The moon then condensed out of it.
A new study in Nature by Wang and Jacobsen has recently come out in favor of the second solution. The study measured two potassium isotopes in both moon rocks and rocks from Earth’s mantle. They found that the moon rocks contained about four parts per ten thousand more of the heavy potassium isotope \41K than the lighter isotope \39K. This could be handily explained by the moon’s condensation from a hot disk of rock vapor.
From: A Cosmic Crash May Have Made the Moon – Facts So Romantic – Nautilus
