The seven worlds of TRAPPIST-1

NASA announces the discovery, via the Spitzer Space Telescope, of a system of seven Earth-sized worlds orbiting the star TRAPPIST-1, only 40 light years from Earth’s solar system. Though water may exist in some state on all seven of the planets, three of them are thought to be orbiting within the “Goldilocks zone” in which liquid water would be abundant, making life possible on the surfaces of those planets.