The Sun was born 4.6 billion years ago in a gigantic cloud of gas and dust – and it wasn’t alone.

Now astronomers believe they’ve found our star’s ‘twin’ which formed at the same time before disappearing off on a lonely journey through space.

This ‘solar sibling’ may even be home to alien organisms because there is a chance that traces of life spread from our own planet during a tumultuous period of our star system’s history.

This era is called The Late Heavy Bombardment or ‘Lunar Cataclysm’ and saw vast numbers of asteroids rain down on Earth, Mars, Venus and Mercury.


Life may have escaped our own planet during an ancient cataclysm and found a home near our sun’s ‘twin’ (Picture: Nasa)

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Could life have escaped from humanity’s home planet aboard an asteroid and then evolved separately on a star just like ours?

This might sound far-fetched, but some scientists believe it’s a real possibility and have dubbed the process by which life can float between star systems ‘interstellar lithopanspermia’.

‘Some theoretical calculations show that there is a non-negligible probability that life spread from Earth to other planets or exoplanetary systems, during the period of the late heavy bombardment,’ said Vardan Adibekyanm of the Instituto de Astrofísica e Ciências do Espaço, who led the team which discovered the star.

‘If we are lucky, and our sibling candidate has a planet, and the planet is a rocky type, in the habitable zone, and finally if this planet was ‘contaminated’ by the life seeds from Earth, then we have what one could dream – an Earth 2.0, orbiting a Sun 2.0.’

A view of a star cluster resembling the one in which our own sun was born

The star is called HD186302 and is the same age as our own sun with an identical chemical composition.

It formed in the same cluster and then set off a space odyssey, which means it’s a very long away from our sun.

Astronomers are now planning to focus their telescopes on the solar sibling to see if it has any planets orbiting it.

As well as the possibility of solving the question of whether life exists elsewhere in the universe, the prodigal sun is also expected to shed light on the process which causes planets to form around stars.

Adibekyan added: ‘Since there isn’t much information about the Sun’s past, studying these stars can help us understand where in the Galaxy and under which conditions the Sun was formed.’