Blue Dot 168: Sister Selene: How Did The Moon-Earth System Come to Be?

Dec 20, 2019

Credit NASA

Longtime listeners to Blue Dot know that Dave has a lifelong fascination with the Moon from its exploration to its role in eclipses. But how did our companion world come to be? 


Since the Apollo missions brought back lunar samples, the most accepted idea is called the "Giant Impact Hypothesis" but the notion has its flaws -- mainly that if a Mars-sized object actually did hit the Earth and create the Moon, where is the evidence in the Moon rocks which are isotopically identical to Earth's?

Enter the recent work by Dr. Sarah Stewart, a MacArthur "genius grant" winner from UC Davis whose team has developed an intriguing new twist on the impact hypothesis.


Using state of the art computer models and high energy laboratory experiments, Stewart and her colleagues including Simon Locke from Cal Tech have a new way to look at how impacts affect the planetary formation process in general and the peculiar Earth-Moon system (which is more like a double planet) in particular. It's not just howling at the Moon!