Astronomers have detected helium escaping from the super-Earth LHS 1140 b, providing the strongest evidence yet that a rocky planet in another star's habitable zone has retained an atmosphere for billions of years.

Science has discovered around 6,000 planets, and this is the first one, other than Earth, that is rocky and has an atmosphere.

A team of astronomers says it has identified a world with the three traits needed to support life, but they see no evidence of life on the faraway rocky planet.

A rocky world orbiting within its star’s habitable zone may be surrounded by a helium-rich atmosphere, providing the strongest evidence yet that planets with Earth-like conditions could support life outside the solar system.