Kepler 452b: Possible 'Earth 2.0' discovered by Nasa

A Nasa mission has discovered what the space agency believes is the closest likeness to Earth found so far - and a possible host to other forms of life in space.

The newly-discovered Kepler 452b - described as a "bigger, older cousin" to Earth - is the smallest planet found so far that lives within a "habitable" zone around a star similar to our own sun.

The planet is 60 percent larger in diameter than ours, but its orbit is only 385 days - 20 longer than Earth.

It is thought to have spent six billion years in the "habitable" zone - 1.5 billion longer than our own planet, and its star has a similar temperature and mass to our sun.

Scientists believe that is more than enough time for life to have been established "somewhere on its surface, or in its oceans".

However, it is currently unclear whether Kepler-452b is, in fact, able to support life.

The "habitable zone" is described as a region around a star where temperatures are right for water - which is essential to the creation of life as we know it.

Jon Jenkins, Kepler data analysis lead at NASA's Ames Research Center in Moffett Field, California, who led the team that discovered the planet, said: "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.”

It was discovered by the telescope on Nasa's Kepler mission, which has so far found 1,030 planets during its search efforts.

While it has discovered several planets in habitable zones, Kepler 452-b is the first near-Earth size discovery in such an area with a star similar to our sun.

Size is significant as extremely large planets are deemed unlikely to have a solid surface.