NASA's Kepler spacecraft has had a busy year, having helped scientists identify hundreds of potentially inhabitable Earth-like planets. Now, a team of experts will expand the telescope's planet-hunting mission to look for life-supporting moons — much like Pandora, the fictional setting for James Cameron's sci-fi blockbuster, Avatar. Here's what's happening:

How will this project work?
In the Hunt for Exomoons with Kepler (HEK) project, a team of experts will use publicly available Kepler data to find moons that boast conditions fit for life — that, in other words, fall within what's known as the universe's "habitable zone." This is an especially "daunting task," says Pete Spotts at The Christian Science Monitor. A single planet can host multiple moons; Jupiter, for instance, has dozens.

Why devote resources to looking at moons, then?
Moons within our own solar system, like Jupiter's Europa, have shown traces of water, one of the keys to sustaining life. Among the 1,235 "planetary candidates" Kepler has helped identify are 10 "Jupiter-sized planets," says Nola Taylor Redd at Though these "gas giants would not boast liquid water on their surface," their circling moons — which are often bigger than Earth — might do so.

What other criteria would a moon have meet? 
To fall within the "habitable zone," it would have to be "at least one-third as massive as Earth," says Redd, and host a surface temperature closely resembling Earth's. The team suspects that certain gas giants may have captured Earth-sized objects into their gravitational orbit during the formative years of their solar systems — turning potential Earth 2.0's into moons.

What are the odds of actually finding life?
Not insignificant. "The amount of secondary science that can be done" using Kepler's data "is amazing," says the HEK project's Allan Schmitt. "We haven't even scratched the surface."

Sources: Christian Science Monitor,, Universe Today