The most Earth-like planet yet has been discovered, scientists report in the journal Science. The rocky planet, Kepler 186f, is close to the size of Earth and has the potential to hold liquid water, which is critical for life, the team says. Nestled in the Milky Way, it is part of a five-planet system that orbits around a cool dwarf star.
It was spotted by the Kepler telescope, which has found nearly 1,000 new worlds since its launch in 2009. "This is the smallest planet we’ve found so far in the habitable zone," said Prof Stephen Kane, an astrophysicist from San Francisco State University, US.
Kepler 186f is about 500 light-years away from the Earth. The researchers estimate that is a little bigger than our planet, with a radius that is about 10% larger than ours.
Because of its size, the team believes it is a rocky planet. Prof Kane explained: "There seems to be a transition that occurs at about 1.5 times the Earth’s radius, such that if the planet is larger, then it starts to develop a very substantial atmosphere very similar to what we see in the gas giant planets in our own Solar System.
"And so anything less than 1.5 is probably more like a rocky planet that we are familiar with."