Nasa's Keplar discovers 'Earth 2.0'

Scientists, though, are still sceptical about earth's closest cousin

The National Aeronautics and Space Administration (NASA) announced late on Thursday the discovery of ‘Earth 2.0’ by its Kepler spacecraft. Nasa describes the planet as “Earth’s bigger, older cousin”, and the first nearly Earth-sized planet found in the habitable zone of a star similar to our sun.

Named as Keplar-452b, it is located nearly 1,400 light-years away from Earth in the constellation Cygnus. It is around 60 per cent bigger than Earth, and its distance from its star is only five per cent greater than the distance between the Sun and the Earth. It sits within the specific region of a solar system where life-sustaining liquid, water, is possible.

Keplar-452b’s star has the same surface temperature and type as that of the sun, and is a G2 star. Stars classified as G2 are the second-hottest in the yellow G class with a surface temperature of nearly 5,800 Kelvins. The newly found star is 10 per cent bigger and 20 per cent brighter than our sun, and is “somewhat older” according to Nasa.

Keplar-452b orbits its star in 385 days, is likely to have a mass five per cent greater than that of the Earth, and has almost twice as much gravity. “Today, Earth is a little less lonely,” Kepler researcher Jon Jenkins said.

Jenkins also said the new planet “almost certainly has an atmosphere”, though scientists weren’t yet sure what it was made of. They expected the atmosphere to be thicker than Earth’s, and the planet to also have active volcanoes.

According to a report in The Guardian, though 452b has more in common with the Earth than any planet yet discovered, its star is 1.5 billion years older and the new planet, as a result, receives 10 per cent more energy than the Earth. That meant it could provide a glimpse into a burning, waterless future on Earth, the scientists said.

“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 added, mentioning 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.”

However, Joseph Twicken, a Seti scientist also on the Keplar mission, said the discovery “takes us one step closer to understanding how many habitable planets are out there”.

Further research will tell if Keplar-452b, or for that matter any other planet already discovered and registered in the Keplar mission’s rich directory, could be an ideal Earth substitute.