Nasa has found a twin Earth orbiting a star like the Sun in the Milky Way which scientists say ‘would feel a lot like home.’
Kepler 452b – which has been dubbed Earth 2.0 – is six billion years old, has a 385 day year and orbits its star at the same distance as us. It is 1,400 light-years away in the constellation Cygnus.
It is believed to be rocky, with active volcanoes and is so like Earth that Nasa believes it is possible that life once inhabited the planet.
Scientists said that the sunshine is so similar that plants could survive if taken to Kepler 452b.
“This is so fascinating because Kepler 452b receives the same kind of spectrum and intensity of light as we do on Earth,” said Dr Daniel Brown, an astronomy expert at Nottingham Trent University.
“This means plants from our planet could grow there if it were rocky and had an atmosphere. You could even get a healthy tan like here on holiday.”
But because it is 1.5 billion years older, scientists say it gives a ‘peek into a crystal ball showing a possible future for Earth’ as it reaches a point where it is no longer habitable.
“If Kepler 452b is indeed a rocky planet, its location could mean that it is just entering a runaway greenhouse phase of its climate history,” said Doug Caldwell, a SETI Institute scientist working on the Kepler mission.
“The increasing energy from its aging sun might be heating the surface and evaporating any oceans. The water vapour would be lost from the planet forever.
“Kepler 452b could be experiencing now what the Earth will undergo more than a billion years from now, as the Sun ages and grows brighter.”
The Kepler spacecraft has been looking for signs of new worlds outside the Solar System since May 2009, and has so far found more than 4,000 planets in the so-called ‘Goldilocks Zone’ – neither too hot, nor too cold to sustain life.
On Thursday Nasa announced they had found 500 new possible planets to add to the 4,175 already found by the telescope, and 12 were ‘Earth-like.’ But Kepler 452b is the first of the 12 to be confirmed as a planet and Nasa said it was the ‘closest’ to Earth that has ever been seen.
It is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet.
“Today the Earth is a little less lonely because there is a new kid on the block,” said Jon Jenkins, Kepler data analysis lead at NASA’s Ames Research Center in Moffett Field, California.
“If you travelled to this star with an arkful of plants…the plants would photosynthesise just perfectly fine. It would feel a lot like home from the standpoint of the sunshine.
“It is six billion years old. That is considerable opportunity for life to arise on its surface and its oceans should all the necessary conditions for life have appeared on this planet.
“This is the closest thing that we have to another planet like the Earth. And the Earth follows nearly in the footsteps of its older cousin and will be there in 1.5 billion years time.”
The discovery gives new hope that alien civilisations may exist beyond the Solar System. Earlier this week Professor Stephen Hawking and the Astronomer Royal Lord Martin Rees announced they were joining a $100 million project to seek out signs of extra-terrestrial intelligence in the Milky Way.
“We won’t be going to this planet but our children’s children’s children might be,” said Jeff Coughlin, Kepler research scientist at SETI Institute in Mountain View, California “It’s a very long term goal but a very exciting one.”
Kepler’s task is to look for rocky planets between half and twice the size of Earth where water could still exist on the surface.
Since liquid water is critical to life on Earth, many scientists believe the search for extra-terrestrial life should focus on planets where liquid water occurs.
The size of the planet also means it has enough gravity to pull in gases like hydrogen and helium to form an atmosphere.
The space observatory detects planets as their orbits cross in front of their star and cause a very tiny but periodic dimming of the star’s brightness.
Nasa is also trying to determine the fraction of the hundreds of billions of stars in our galaxy that might have such planets.
“We’re trying to answer fundamental questions, Where do we come from, where are we going? What’s the future of our Solar System,” John Grunsfeld, associate administrator for NASA’s Science Mission Directorate .
“We’re going to take one small step in answering that question today.” (BBC News)