http://www.msnbc.msn.com/id/46467275...e#.T0QJifXwGSoScientists have discovered a new type of alien planet — a steamy waterworld that is larger than Earth but smaller than Uranus.
The standard-bearer for this new class of exoplanet is called GJ 1214b, which astronomers first discovered in December 2009. New observations by NASA's Hubble Space Telescope suggest that GJ 1214b is a watery world enshrouded by a thick, steamy atmosphere.
"GJ 1214b is like no planet we know of," study lead author Zachory Berta of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., said in a statement. "A huge fraction of its mass is made up of water."
Adding to the diversity
To date, astronomers have discovered more than 700 planets beyond our solar system, with about 2,300 more "candidates" awaiting confirmation by follow-up observations.
These alien planets are a diverse bunch. Astronomers have found one planet as light and airy as Styrofoam, for example, and another as dense as iron. They've discovered several alien worlds that orbit two suns, like Luke Skywalker's home planet of Tatooine in the "Star Wars" films.