Kepler 22b may not be a second Earth, but it may be another Neptune (Image: NASA)
The ongoing search for Earth-like worlds has taken another promising step. On December 5, NASA announced the discovery of the planet most likely so far to sustain life outside of the Solar System. The exoplanet, given the undramatic name of Kepler 22b, was found by NASA's Kepler spacecraft as part of its mission to seek out Earth-type planets in our galaxy. Though Kepler 22b is not the first such planet to be detected in recent years, it is the first one orbiting a star similar to our Sun and at a distance where it is capable of possessing liquid water, which most scientists regard as essential for life to exist. Though this is a significant milestone, the question remains, how good a candidate for a second Earth is Kepler 22b? Could there be life there or is it a planetary blind alley?