Astronomers hunting for another Earth have found the closest match yet, a potentially rocky planet circling its star at the same distance as our home orbits the Sun.

Named Kepler 452b, the planet is about 60 per cent larger than Earth. It could have active volcanoes, oceans, sunshine like ours, twice as much gravity and a year that lasts 385 days, NASA scientists said on Thursday.

“Today we are announcing the discovery of an exoplanet that, as far we can tell, is a pretty good close cousin to the Earth and our Sun,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington.

NASA has made a handful of such announcements in the past, but each of those discoveries fell short of being Earth-like in one way or another, such as being too hot to host life or having a surface that was likely gaseous rather than hard and rocky.

“This is about the closest so far,” Grunsfeld added, describing Kepler 452b as our “closest twin”, or “Earth 2.0”.

The planet was detected by the US space agency’s Kepler Space Telescope, which has been hunting for other worlds like ours since 2009.

This planet sits squarely in the Goldilocks zone of its star, where life could exist because it is neither too hot nor too cold to support liquid water, the US space agency said.

“Today the Earth is a little less lonely,” said Jon Jenkins, Kepler data analysis lead scientist at NASA’s Ames Research Center in Moffett Field, California.

“Because there is a new kid on the block that just moved in next door, in terms of the surface temperature of the star it orbits and the energy it receives from its star.”

Kepler 452b’s star is 1.5 billion years older, four per cent more massive and 10 per cent brighter than our Sun.

But at a distance of 1,400 light-years away, humankind has little hope of reaching this Earth-twin any time soon.

– NZME/NASA