Lost and found

摘要

The Kepler telescope was launched into space in 2009 to look for extrasolar planets, those that circle stars other than the sun. Since then it has spotted more than 2,700 potential alien worlds, including some that appear to be small, rocky and far enough from their stars for liquid water to exist on the surface-rather like Earth, in other words, and thus, just possibly, hospitable to life. In doing so it made "exoplanet" research one of the busiest areas of astronomy. It also whetted planet-hunters' appetites. Originally meant to collect data for 3~1_2 years, last year its mission was extended until 2016.