Earth-Like Planet Could Be Just 13 Light Years Away (PICTURES)

'Mirror-Earth' Could Be Just 13 Light Years Away

Astronomers have announced that an Earth-like planet could exist as close as 13 light years to Earth.

Yes, that's still about 76 million million miles - or the length of 11,000 million million London buses.

But astronomically speaking? It's not too far.

An Earth-like planet is defined roughly as a rocky world about the size of our planet, orbiting a star within the 'goldilocks zone' where liquid water - and life - is thought to be possible.

The projection is based not on a direct discovery of a new planet, but an analysis of where the planets we've discovered so far are located and how they are spread through the galaxy.

The team at the Harvard-Smithsonian Center for Astrophysics used data from Nasa's planet-hunting Kepler telescope for their study.

Kepler is currently watching about 150,000 stars, and measures planets orbiting those stars by looking for dips in brightness caused when planets pass in front of them.

But Kepler is unable to discover every planet around those stars, because many either don't orbit in the right place, and may be masked by other fluctuations in brightness.

Knowing this, the team used a sample of just under 4,000 red dwarf stars being watched by Kepler and found that about 95 exoplanets are thought to be in orbit around them - three of which are Earth like.

This means about 6% of stars in our galaxy could have Earth-like planets, which is 4.5 billion Earths - and a lot of chances for life to emerge.

It also means that since there are 248 red dwarfs within 30 light years of our sun, it is likely that within 13light years there is a planet resembling our own.

The study's author, Courtney Dressing, said if the galaxy was the size of the United States, this distance was the equivalent of strolling over New York's Central Park.

So far the nearest Earth-size planet has been found orbiting Alpha Centauri Bb, though it is far too hot to host life.

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