Astronomers have found a planet they say is ‘the closest twin to Earth’ ever seen.
Named Kepler-452b, the planet is the smallest world discovered orbiting in the habitable zone of a star.
What makes this world remarkable is that it orbits its star at about the same distance that Earth orbits the sun. What’s more, its home star looks to be similar to our sun.
This Earth-like world has a ‘substantial opportunity’ to host life, Nasa says, adding that if plants were transferred there, they would likely survive.
The planet is 60 per cent bigger than Earth, and is located about 1,400 light years away in the constellation Cygnus.
Its discovery brings the total number of confirmed planets to 1,030.
It is ‘the closest twin to Earth, or the Earth 2.0 that we’ve found so far in the dataset’, said John Grunsfeld, associate administrator of Nasa’s Science Mission Directorate.
Kepler-452b is larger than Earth, but its 385-day orbit is only 5 per cent longer.
It resides in something known as the habitable zone – or Goldilocks zone – which is an area around a star where liquid water could pool on the surface of an orbiting planet.
It is also 5 per cent farther from its parent star Kepler-452 than Earth is from the sun.
‘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. Getting to our closest twin planet might take a while though, since it’s 1,400 light years away.’
Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 per cent brighter and has a diameter 10 per cent larger.
While its mass and composition are not yet known, previous research suggests that planets the size of Kepler-452b have a good chance of being rocky.
‘We can think of Kepler-452b as an older, bigger cousin to Earth,’ said Jon Jenkins, Kepler data analysis lead at Nasa’s Ames Research Center.
‘It’s awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star’ longer than Earth.
‘That’s substantial opportunity for life to arise, should all the necessary ingredients and conditions for life exist on this planet.’
To help confirm the finding and better determine the properties of the Kepler-452 system, the team conducted ground-based observations.
These measurements were key for the researchers to confirm the planetary nature of Kepler-452b, to refine the size and brightness of its host star and to better pin down the size of the planet and its orbit.
‘Kepler 452b could be experiencing now what the Earth will undergo more than a billion years from now,’ said Doug Caldwell, a Seti Institute scientist on the Keplar mission.
‘If Kepler 452b is indeed a rocky planet,’ he said, its location ‘could mean that it is just entering a runaway greenhouse phase of its climate history.
‘Its ageing sun might be heating the surface and evaporating any oceans. The water vapour would be lost from the planet forever.’
The research paper reporting this finding has been accepted for publication in The Astronomical Journal.
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