The Kepler space telescope, launched nearly two years ago, has already proven its worth as an exoplanet hunter many times over. But the discoveries keep on coming. NASA just announced that Kepler has found its first rocky planet--and that the rocky world is only 1.4 times the size of Earth, making it the smallest exoplanet ever found. Phil Plait explains that this nearly Earth-sized isn't actually Earth-like and habitable:
[I]t orbits extremely close in to its star, circling over the star’s surface at a distance of roughly 3 million kilometers (1.8 million miles) — amazingly, it takes less than an Earth day to make one circuit. But being that close to a star comes at a price: the surface temperature of the planet must be several thousand degrees!
The planet, Kepler-10b, may not be habitable to life as we know it, but Plait is still plenty excited. Get the rest of the story on how the planet was found and what its discovery means over at Bad Astronomy
. Related Content: 80beats: Astronomers Predict a Bonanza of Earth-Sized Exoplanets
DISCOVER: How Long Until We Find a Second Earth?