Author: Francis Nimmo, Professor of Earth and Planetary Sciences, University of California, Santa Cruz

A physicist, a chemist and a mathematician walk into a bar. It sounds like the start of a bad joke, but in my case, it was the start of an idea that could reshape how scientists think about the history of the Moon. The three of us were all interested in the Moon, but from different perspectives: As a geophysicist, I thought about its interior; Thorsten Kleine studied its chemistry; and Alessandro Morbidelli wanted to know what the Moon’s formation could tell us about how the planets were assembled 4.5 billion years ago. When we got together to discuss how…