Astronomers announced today that they have discovered a new type of planet – a rocky world weighing 17 times as much as Earth. Theorists believed such a world couldn’t form because anything so hefty would grab hydrogen gas as it grew and become a Jupiter-like gas giant. This planet, though, is all solids and much bigger than previously discovered “super-Earths,” making it a “mega-Earth.”"We were very surprised when we realized what we had found,” says astronomer Xavier Dumusque of the Harvard-Smithsonian Center for Astrophysics CfA, who led the data analysis and made the discovery.
via Astronomers Find a New Type of Planet: The “Mega-Earth” | www.cfa.harvard.edu/.