Launched in 2009, NASA’s Kepler space telescope has spotted thousands of what might be extrasolar planets. Now, two researchers have determined that exomoons are also likely candidates for supporting life. Rory Barnes of the University of Washington and the NASA Astrobiology Institute, and Rene Heller of Germany’s Leibniz Institute for Astrophysics Potsdam, are investigating whether extrasolar planets might have habitable moons. Of approximately 850 known planets beyond our solar system, most are gas giants like Saturn and Jupiter, and few have a solid surface and orbits in the “habitable zone.” Barnes and Heller say conditions on exomoons are probably quite different from those on exoplanets. “An observer standing on the surface of such an exomoon,” said Heller, “would experience day and night in a totally different way than we do on Earth. For instance, stellar eclipses could lead to sudden total darkness at noon.”
Heller and Barnes created a theoretical model that deduces minimal distances an exomoon could be from its planet and support life. This is called the "habitable edge." The model will help future astronomers to figure chances for life on exomoons. One wonders how the world will react if life—of any sort—is detected out there. We might find out some time in the next 10 years, thanks to the amazing photometric precision of NASA's Kepler space telescope.