Scientists have for the first time pinpointed the source of a meteorite that came from the moon. By measuring the rock's age, the researchers have precisely dated the rock's lunar home, the Imbrium impact basin, which is the youngest of the moon's large impact craters. That crater's age may have special significance because Imbrium's formation marks the end of an era in which space debris walloped the inner solar system. Researchers have long argued that life on Earth couldn't have evolved until after that bombardment.
Found in the desert of Oman in 2002, the 7-ounce stone has a greenish hue mixed with bits of white. That appearance is typical of lunar rocks, but this meteorite turns out to be exceptional.