Moons similar to the one depicted in Hollywood flick '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.
All are giant gaseous worlds similar in size to Jupiter or Neptune. 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, researchers now believe, the 'Daily Mail' reported.
Pandora, the fictional moon in James Cameron's movie 'Avatar', is just such a world.
So far only one of the 15 newly discovered objects has been confirmed as an exoplanet with 99.9 per cent 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 several hundred light years away.
"There's an obsession with finding Earth-like planets but what we are discovering with planets such as PH2 b is far stranger," Astronomer Dr Chris Lintott, from Oxford University, a member of the international team behind the discovery, said.
"Jupiter has several large water-rich moons. Imaging dragging that system into the comfortably warm region where the Earth is," Lintott said.
"If such a planet had Earth-size moons, we'd see not Europa and Callisto but worlds with rivers, lakes and all sorts of habitats: a surprising scenario that might just be common," Lintott added.
"It may be that the most common habitable worlds are moons around Jupiter and Neptune-size planets rather than rocky planets as in our own solar system," Lintott said.
Members of the public helped astronomers identify the candidate exoplanets by logging onto the planethunters.org website on their home computers.
Follow-up work with the Keck telescope in Hawaii provided the proof that PH2 b is almost certainly a genuine planet.
"We can speculate that PH2 b might have a rocky moon that would be suitable for life," Dr Ji Wang, another Planet Hunters scientist from Yale University, said.
"I can't wait for the day when astronomers report detecting signs of life on other worlds instead of just locating potentially habitable environments. That could happen any day now," Wang said.
More than 40 volunteers are credited in a paper on the research published by the Astrophysical Journal.