Posted: Fri, Aug 17, 2001, 9:54 AM ET (1354 GMT)
A paper published this week lends new credence to the proposal that a giant impact early in the history of the solar system formed the Earth's Moon. The study, published in Thursday's issue of the journal Nature, used advanced computer modeling to simulate an impact of a Mars-sized planetesimal with the Earth. Those simulations showed that such an impact could create the Moon and explain why the Moon is relatively poor in iron compared to the Earth. The "giant impact" hypothesis had existed for a quarter-century and had become the leading explanation for the Moon's genesis, but this latest study, using more advanced computer modeling of impact physics, shows that such an impact can form the Moon without the requirement for additional modification of the Earth or Moon after the impact.

Related Links:

•  SwRI press release
•  SPACE.com article