Moon Born in a 5-Hour Flash After Giant Impact, New Study Suggests

New simulations considering the internal temperatures and material strengths of early Earth and Theia suggest the Moon could form within about five hours after the Theia–Earth giant impact if Theia was relatively warm; cooler, slower-forming scenarios are also possible. This refines the leading giant-impact theory, indicating the Moon largely originated from Theia’s mantle with a bit from Earth, and implies the Moon’s volatile content and isotopic differences may reflect the thermal state at impact. The findings have implications for exomoon searches and the Moon’s formation timeline.