Researchers design a robot to explore the moon's mysterious volcanic…

Three years ago, Japanese researchers discovered a cavern on the moon using the SELENE satellite. It's estimated that the subterranean structure is 65 meters wide and at least 80 meters in depth. Given that it's too deep to be a crater, and that it was likely carved by lava, it's a natural cavern that's just begging… » 11/20/12 3:10pm 11/20/12 3:10pm