Known as Kepler-10c, it orbits a star about 560 light-years away. Scientists described its properties at an American Astronomical Society meeting in Boston.
Theorists had always thought that any planet that large would pull so much hydrogen on to itself that it would look more like a Neptune or a Jupiter.
“The proper way to call it is something bigger than a ‘super-Earth, so how about ‘mega-Earth,” Prof Dimitar Sasselov, of the Harvard-Smithsonian Center for Astrophysics (CfA), told reporters. He also used the phrase, “the Godzilla of Earths!”.
One point raised at the meeting was that very old star systems might in fact harbour life.
“It is [on] solid planets that is the place, as far as we know – and we very little about the origins of life – where we think the chemistry is capable of building those molecules that lead to the emergence of life from geochemistry,” says Prof Sasselov.
It’s not just that we know very little about the origin of life, but that most of what we think we know is implausible nonsense that gets in the way of understanding. For a brief explanation, see The Science Fictions series at your fingertips (origin of life)