MOONS like the one depicted in the film 'Avatar' may be among the most common places to find alien life, scientists believe.
Astronomers came to the conclusion after identifying up to 15 new planets orbiting the life-friendly "habitable zones" of stars.
While such planets would not themselves be suitable for Earth-like life, they could be circled by moons on which there are forests, oceans and living creatures.
So far only one of the 15 newly discovered objects has been confirmed to be an exoplanet with 99.9pc certainty. The rest still fall into the category of "candidate" planets while further evidence is collected.
The confirmed planet, known as PH2 b, orbits a sun-like star in the constellation Cygnus, which is several hundred light years away.
Dr Chris Lintott, from Oxford University, a member of the international team behind the discovery, said: "It may be that the most common habitable worlds are moons around Jupiter and Neptune-sized planets rather than rocky planets as in our own solar system."