"Given that most planet-detection campaigns cannot detect planets beyond 5-10 AU from their host stars, our results provide new clues about the characteristics of planetary systems in a regime that is poorly constrained by current observations, " Kaib told SPACE.com.

MSN: Alien planets face danger from double-star systems

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.

BBC: Viewpoint: The obsession with a 'twin Earth'