SpaceX has finally reached the Moon, just not the way Elon Musk planned. A discarded upper stage from a SpaceX Falcon 9 rocket slammed into the lunar surface early Wednesday at roughly 8,700 kilometers per hour, or 5,400 mph, ending more than a year of uncontrolled flight through space. The rocket hit at roughly seven times the speed of sound, releasing energy equivalent to about three tons of TNT and blasting a new crater into the Moon. “Scientists are certain a wayward SpaceX rocket slammed into the moon as predicted,” the Associated Press reported, citing Boston University’s Carl Schmidt, who…