New study: 1/3 of Sun-like stars might have terrestrial planets in their habitable zones

A paper has been accepted for publication in a science journal (PDF) where the author has analyzed data from NASA's Kepler planet-finding observatory, trying to figure out how many Earth-sized planets there might be in the galaxy orbiting their stars in their habitable zones; that is, at the right distance so that the star warms the planet enough to have liquid water. In the paper, he estimates that on average 34% (+/-14%) of Sun-like stars have terrestrial planets in that Goldilocks zone. 34%!