There's a slight chance that the Earth could get hit by an asteroid in about 170 years, but don't you worry -- NASA's all over it. This week, the agency announced a new mouthful of a mission known as Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer, or OSIRIS-REx, for short. The $800 million initiative, part of NASA's New Frontiers Program, will send a spacecraft to link up with 1999 RQ36 -- a nearby asteroid that's likely rich in carbon and other organic molecules that could explain how life forms originated. After about four years of space travel, the craft should get close enough to map the asteroid's surface, bef
