cylonlover writes "It's been more than three and a half years since the Kepler Space Telescope began its mission as humanity's watcher for Earth-like planets outside of the Solar System. In that time, Kepler has done exactly what was asked of it: provide the data to help identify more than 2,300 exoplanet candidates in other star systems. And so NASA has announced the 'successful completion' of Kepler's prime mission. There's one nagging detail, though: we are yet to find a truly Earth-like planet. It's time to alter the parameters of the search, which is why NASA has announced Kepler will now begin an extended mission that could last as long as four years."