The so-called “mega-Earth” circles a very old star called Kepler-10, which is located about 560 light-years away from Earth in the constellation Draco.
Physicist Dimitar Sasselov, the Director of the Harvard Origins of Life Initiative, said the discovery, announced at the American Astronomical Society meeting in Boston, U.S., was a surprise since big planets were believed to be mostly gas, not solid rocky bodies like Earth or Mars.
He added that large planets should gather up massive amounts of gas in the process – or so scientists thought.
“However the mega-Earths are formed, the discovery of another type of rocky world augurs well in the search for life beyond Earth,’’ Sasselov added.
Related research shows that about 75 per cent of the planets found with NASA’s Kepler space telescope are less than four times Earth’s diameter.
In the solar system, there is nothing between the size of Earth, the largest rocky planet, and Neptune, the smallest gas giant with a diameter nearly four times Earth’s.
