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.
Pandora, the fictional moon in 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% 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.
Astronomer Dr Chris Lintott, from Oxford University, a member of the international team behind the discovery, said: “There’s an obsession with finding Earth-like planets but what we are discovering with planets such as PH2 b is far stranger.
“Jupiter has several large water-rich moons. Imaging dragging that system into the comfortably warm region where the Earth is. 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.
“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.”
( via independent.co.uk )