The Kepler space telescope is not quite dead. NASA’s planet-hunting space observatory got a second chance at life this year. And mission scientists analyzing already-collected data unearthed hundreds of new worlds, including a potentially habitable Earth-sized planet.
For four years, Kepler stared at one patch of sky in the constellations Cygnus and Lyra and monitored roughly 150,000 stars for tiny dips in starlight — silhouettes of orbiting planets. Kepler’s goals included counting planetary systems and stars hosting planets the size of Earth.
In April, the Kepler team reported the smallest potentially habitable exoplanet known: Kepler 186f, about 490 light-years away. It is just 10 percent wider than Earth and orbits its dim, red star at a distance where liquid water could exist (SN: 5/17/14, p. 6). But astronomers don’t know if the planet can support life.