NASA's Kepler mission to find habitable planets orbiting Sun-like stars has turned up its first rocky planet. The project uses the Kepler space telescope to identify extrasolar planets by watching for dips in the intensity of light from up to 170,000 target stars.

Natalie Batalha of San Jose State University in California and her group spotted Kepler 10b, which is about 4.56 times the mass of Earth. Although similar in size to Earth, its orbit lasts just 0.84 days, making it likely that the planet is a scorched, waterless world with a sea of lava on its starlit side.

Astrophys. J. 729, 27 (2011)