AN astronaut attempting to visit recently discovered planet GJ1214b would land in hot water - literally, US scientists say.
Researchers at the Harvard-Smithsonian Center for Astrophysics said they have identified an entirely new kind of planet, dominated not by rock, gas or other common materials, but water.
The planet is "a waterworld enshrouded by a thick, steamy atmosphere," they said in a statement, after scrutinising the planet with NASA's Hubble Space Telescope.
"GJ1214b is like no planet we know of," astronomer Zachary Berta said. "A huge fraction of its mass is made up of water."
GJ1214b was discovered in 2009 by the ground-based MEarth Project. Described as a "super-Earth," it is about 2.7 times Earth's diameter and weighs almost 7 times as much.