Via Sky News
A rocky planet dubbed a “mega earth” has been discovered in a distant star system.
The planet, known as Kepler-10c, is so old that theoretically it should have become a “Jupiter-like gas giant” – but has remained solid like Earth.
It is 17 times bigger and twice as old as Earth, and its discovery suggests potentially life-bearing rocky planets could be far more abundant than previously thought.
“This is the Godzilla of Earths, but unlike the movie monster, Kepler-10c has positive implications for life,” said Dr Dimitar Sasselov, from the Harvard-Smithsonian Center for Astrophysics.
“Finding Kepler-10c tells us that rocky planets could form much earlier than we thought. And if you can make rocks, you can make life.”
The Kepler-10 star system is an estimated 11 billion years old, which means it formed less than three billion years after the Big Bang.
Earth is roughly 4.5 billion years old.
Kepler-10c circles its equivalent of the Sun – part of the Draco constellation – every 45 days.
It has at least one neighbour, known as Kepler-10b, which is a scorching “lava world” that navigates its star in just 20 hours.
Observers at the Italian Galileo National Telescope in the Canary Islands realised the planet was made from rock – not gas – after discovering it had 17 times the mass of Earth.
“We were very surprised when we realised what we had found,” said astronomer Dr Xavier Dumusque, also from the Harvard-Smithsonian Center for Astrophysics, who led the research.
“Kepler-10c didn’t lose its atmosphere over time. It’s massive enough to have held onto one if it ever had it – it must have formed the way we see it now.”