Kepler Ongoing

摘要

Launched in 2009, NASA's Kepler spacecraft has entered an extended phase, having completed its planned 3.5 years of observing. The mission has surveyed 150,000 stars and found more than 2740 planet candidates, 115 of which astronomers have confirmed to be planets by follow-up observations using ground-based telescopes. Several of the candidates are Earth-sized or smaller; in February, astronomers confirmed one of them to be a planet approximately the size of our moon. Data from Kepler are helping researchers get a better handle on how abundant different kinds of planets are.