Animation of Kepler passing the planet-finding torch to TESS. 10 second version.
After nine years in space, NASA's Kepler has reached its end. The Kepler and K2 missions have discovered over 2,600 confirmed exoplanets so far, including some in the habitable zones of their stars. Kepler used transits--regular dips in a star's brightness caused by orbiting planets--to find new worlds. It's the same method used by NASA's Transiting Exoplanet Survey Satellite. In a way, Kepler has passed the planet-finding torch on to TESS, which will scan nearly the entire sky to continue the hunt for exoplanets.