Huge quantities of water vapour have been detected on a ‘super-Earth’ 40 light years away – even more water than exists here.
What's more, researchers believe that it once lingered in the so-called 'Goldilocks Zone' near its star, before wandering closer in and heating up.
Astronomers at America's Harvard-Smithsonian Center for Astrophysics (CfA) used the Hubble Space Telescope to probe the planet - discovered in 2009 and codenamed GJ1214b - and proved that it is a waterworld enshrouded by a thick, steamy atmosphere.
‘GJ1214b is like no planet we know of,’ said astronomer Zachory Berta. ‘A huge fraction of its mass is made up of water.’
Theorists expect that GJ1214b formed farther out from its star, where water ice was plentiful, and migrated inward early in the system's history.