Finding Life Bearing Exomoons

Of the thousands of exoplanets found so far by NASA's Kepler spacecraft, 37 Neptune-sized worlds and 10 more that are Jupiter-sized orbit within the habitable zone of their parent stars. While they are not necessarily good candidates to be the home of life (though Carl Sagan once imagined life flourishing in more benign layers of the huge atmospheres surrounding such planets), possible terrestrial type moons orbiting those worlds could support life.

Astronomers are now developing techniques that will allow them to detect such moons. Just as Kepler finds planets by observing dips in starlight signifying a planet could be crossing the star's disk, astronomers are refining that approach so they can see the even tinier dips caused by a moon. They believe they can detect moons about one-third the size of Earth. Any smaller than that and the world probably couldn't hold a life-supporting atmosphere in any case.