Study of moon rocks shows barrage 4 million years ago was mainly asteroids
Friday, May 18, 2012 - 09:01
in Astronomy & Space
(Phys.org) -- Researchers have known for some years that the Earth and moon were subjected to a veritable barrage of objects striking their surfaces nearly four million years ago, but less certain was whether those objects were asteroids, comets or even pieces of other protoplanets after they broke apart. Now however, new research by a group of lunar scientists has found, after studying moon rocks brought back by astronauts during the Apollo 16 mission, that it appears they were mostly asteroids. But not, they write in their paper published in the journal Science, the same kind as we see falling on our planet today.