Searching for Life on 7 Nearby Alien Worlds: How Scientists Will Do It

An international research team announced today (Feb. 22) that seven roughly Earth-size alien worlds orbit the small, dim star TRAPPIST-1, which lies just 39 light-years from Earth. Three of these planets appear to be in TRAPPIST-1's "habitable zone," the range of distances where liquid water (and, by extension, life as we know it) could potentially exist on a world's surface.