Gases trapped in lunar meteorites hint that the moon was formed out of material displaced from Earth after a planetary collision.
Roughly 4.5 billion years ago, a primordial version of Earth covered in molten lava orbited the sun. Barely into its newfound existence, it was struck by a smaller object the size of Mars, referred to as Theia, in an explosive event. Theia was blown to pieces by the impact, while a huge chunk of Earth was sent careening into space. The gravitational pull of the remaining bulk of our planet saw this material swirl around Earth. In a surprisingly short span of time, perhaps less than 100 years, some of that material stuck together and formed the moon. Or at least, this is how one popular moon origin theory goes. Now, though, there's fresh evidence to suggest that the moon was indeed created from the debris of this cosmic impact billions of years ago. The discovery of certain gases inside the moon supports the idea, and also gives us important new details on how it might have happened. While completing her PhD at the Swiss Federal Institute of Technology (ETH) in Zurich, Patrizia Will studied six lunar meteorites recovered by NASA…