The newfound world, dubbed Kepler-22b, is much bigger than our planet - but, even so, it's also the smallest world yet discovered outside our Solar System, and finding it does bode well for the eventual detection of a true twin, a planet that really is a second Earth.
Since the very first planets outside our solar system were discovered in the early 1990s, the hope has been to find an "Earth twin" - a planet like ours, orbiting a star like ours, at a distance like ours.