Why NASA is sending a spacecraft to an asteroid to bring a piece back

Not to be outdone by their ESA colleagues, NASA is sending a spacecraft to an asteroid to bring a piece of it back. Her name is OSIRIS-REx, and she will be visiting Bennu—great name for an outpost in a sci-fi movie—one of the primordial asteroids that have been orbiting the Sun for millions of years. This is why: » 11/18/14 12:58pm 11/18/14 12:58pm