The Kepler Mission and the Search for Earth-Like Planets February 6, 2009

Astronomers have confirmed the existence of 307 planets orbiting 263 different stars in our local "neighborhood" within the Milky Way. None, though, are Earth-sized bodies located in the "life zones" of their parent stars. With extrasolar planet searches in their relative infancy, it is no surprise that the planets we have found so far tend to be large and orbiting their stars rather quickly - these types are easiest to locate. The Kepler spacecraft is designed to survey over 100,000 nearby stars, and could open the floodgates of discovery of Earthlike planets in the immediate stellar neighborhood - or indicate that Earth is perhaps indeed a cosmic rarity. The fact that either result is entirely plausible shows just how little we actually know about this emerging branch of astronomy.