Nasa Curiosity rover finds evidence Mars was habitable

Nasa's Curiosity rover has found strong evidence that Mars was once habitable.

The most detailed study so far of the Martian atmosphere suggests the planet was not unlike Earth more than 4 billion years ago.

It's thought Mars once had a thick atmosphere, protected by a magnetic field.

This supports the view that it would have been warm and wet on Mars' surface with running water - believed to be vital to support life.

But it's likely the atmosphere was ripped away over billions of years by solar wind, after the magnetic field collapsed.