Galaxy Hosts 10 Billion 'Habitable' Earth-Size Worlds

Data suggest there's about 10 billion Earth-sized worlds orbiting within their star's habitable zones in the Milky Way.

November 4, 2013
3:00 PM EST
Artist's impression of the five-planet Kepler-62 system, with two worlds in the habitable zone -- the distance from their star at which they receive enough light and warmth for liquid water to theoretically exist on their surfaces. | David A. Aguilar (CfA)