The Moon Is 100 Million Years Younger Than Thought

This artist's conception of a planetary smashup whose debris was spotted by 
NASA's Spitzer Space Telescope in 2009 gives an impression
 of the carnage that would have been wrecked 
when a similar impact created Earth's moon.
 Image released Oct. 17, 2012.Credit: NASA/JPL-Caltech

The moon is quite a bit younger than scientists had previously believed, new research suggests.

The leading theory of how the moon formed holds that it was created when a mysterious planet — one the size of Mars or larger — slammed into Earth about 4.56 billion years ago, just after the solar system came together. But new analyses of lunar rocks suggest that the moon, which likely coalesced from the debris blasted into space by this monster impact, is actually between 4.4 billion and 4.45 billion years old.

The finding, which would make the moon 100 million years younger than previously thought, could reshape scientists' understanding of the early Earth as well as its natural satellite, researchers said.