When spacecraft first transmitted the images of the moon's far side to Earth, we saw the lunar farside lacks the large dark areas called maria, or seas. Why?
The theory that the moon formed when a planet-sized body named Theia crashed into Earth is supported by new evidence using samples from Apollo missions.
Once they looked, astronomers began finding many asteroids near Earth. The one passing Sunday, June 8 is an especially big one, found only two months ago.