Earth’s ‘larger, gassy twin found’

Earth’s gassy twin has been discovered in another solar system 200 light years away.

The planet, known as KOI-314c, weighs the same as the Earth but is 60% larger, leading scientists to suspect it has a thick gaseous atmosphere.

It orbits a dim red dwarf star at such a close distance that temperatures on its surface could be as high as 104C — too hot for most forms of life on Earth.

KOI-314c is only 30% more dense than water. This suggests that the world is enveloped by a blanket of hydrogen and helium hundreds of miles thick.

Scientists believe it may have started life as a mini-Neptune before some of its atmospheric gases were blasted away by intense radiation from the parent star.

Lead astronomer Dr David Kipping, from the Harvard-Smithsonian Centre for Astrophysics in the US, said: “This planet might have the same mass as Earth, but it is certainly not Earth-like.

“It proves that there is no clear dividing line between rocky worlds like Earth and fluffier planets, like water worlds or gas giants.”

The findings were presented at the annual meeting of the American Astronomical Society in Washington DC.

Opening of the American Astronomical Society. Prof David Helfand AAS President. #nasasocial pic.twitter.com/4MytcfemMF

— John Grunsfeld (@SciAstro) January 6, 2014

To weigh KOI-314c, the scientists used a new technique called transit timing variations (TTV), which only works when more than one planet orbits a star.

The new discovery was made by chance as scientists scoured data from the Kepler space telescope looking for evidence of moons rather than planets.