Kepler, RIP

IT USED TONASA be that finding even one new planet was enough to make an astronomer’s career. Uranus was discovered in 1781 by William Herschel, who these days has, among other things, space telescopes, asteroids, schools and a street in Paris named in his honour. Urbain le Verrier, who predicted the existence of Neptune in 1846, based on its gravitational influence on Uranus, has likewise given his name to craters, asteroids and bits of the French capital. It is one of 72 engraved into the sides of the Eiffel tower.These days, though, astronomers can do better. William Borucki has thousands to his name. He is the researcher who conceived of and ran , a planet-hunting space telescope that was launched in 2009. On October 30th announced that, after nearly a decade in space, had run out of fuel and would be retired. has discovered around 2,600 exoplanets—those that orbit stars other than the sun. Another 3,000 candidates await confirmation from ground-based telescopes. The result has been a revolution in astronomy. Its practitioners had long assumed that other stars were likely to have planets of their own. These days, they know that to be true.