NASA's Kepler Mission: A Bounty of Planets Orbiting Distant Stars

Astronomers first detected planets around other stars – known as exoplanets – in the 1990s, but initially they were only able to discover giant planets that are hotter than a pizza oven. As time progressed, smaller and cooler exoplanets have been found. NASA launched the Kepler spacecraft in 2009 to search for more Earth-like worlds. Kepler has found more than 4,000 planet candidates, 1,000 of which have been verified as true exoplanets.  Most are clearly inhospitable for life as we know it, but two are only slightly larger Earth and also may be as temperate.

Speaker: Jack J. Lissauer, NASA Ames