WASHINGTON, Sept. 16 (UPI) -- Our moon was bombarded by two distinct waves of asteroids or comets in its youth, leaving it surface more complex than previously thought, U.S. scientists say.
New results from NASA's Lunar Reconnaissance Orbiter spacecraft are featured in papers appearing in the Sept. 17 issue of Science, NASA said in a release Thursday.
LRO data shows there were two separate populations of impacts on the moon's surface with the earlier period featuring much larger impacts than the later assault, James Head of Brown University wrote in a study.
The rich record of craters on the moon can give clues to the effects of similar impacts in Earth's early history, he said.
"The moon is thus analogous to a Rosetta stone for understanding the bombardment history of the Earth," Head said. "Like the Rosetta stone, the lunar record can be used to translate the 'hieroglyphics' of the poorly preserved impact record on Earth."
Previous lunar maps had different resolutions, viewing angles and lighting conditions, which made it hard to consistently identify and count craters. Head and his team used instruments aboard the NASA orbiter to build a map that highlights lunar craters with unprecedented clarity, they said.
