DISCOVERY OF MOST EARTH-LIKE PLANET
The Kepler telescope has discovered the most Earth-like planet, Kepler 186f, part of a five planet system around a small cool star about 500 light years distant from Earth.
The planet's radius is about 10% larger than Earth. It is the outermost of the five planet system, orbiting its star in around 130 days. Importantly, it may have the potential to hold water since its path is not too close or two far from the star - the 'habitable zone' - where the water doesn't boil, or freeze.
Professor Stephen Kane from San Francisco State University 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 giants in our own solar system. And so anything less than 1.5 is probably more like a rocky planet that we are familiar with'.
Kepler 186f is the most similar planet to Earth yet discovered, despite its star being very different from our Sun.
Nearly 2,000 of these exoplanets have now been discovered, about half by the Kepler telescope.