A Field Guide to the Planets Season 1 Episode 22 Closing in on Earthlike Exoplanets

Beginning in 2009, the Kepler Space Telescope began staring intensively at a single patch of sky, about one quarter of one percent of the sky. Sift through the Kepler discoveries for planets with a variety of Earth-like features, including presence in a habitable zone, and learn why billions of Earth-like planets are estimated to exist in our galaxy.