This has been a good year for space: We celebrated the 40th anniversary of the moon landing and a backyard astronomer spotted an Earth-sized hole in Jupiter's atmosphere. In all of this, we're reminded of our boundless curiosity about the cosmos, and about that nagging question, "Are we alone?" NASA's Kepler Mission will address just that. A space-based telescope, launched in March, will tell us how commonplace (or not) Earth-like planets are, thus answering a long-standing question once and for all. The expectation is that there are billions of Earth-like cousins peppering the Milky Way.