Recently, NASA revealed the discovery of five new planets. And now they seek to discover life-bearing moons which could make those featured in Avatar and Star Wars a fantastic reality. Currently, no moons have been found that are capable of supporting life. But NASA's Kepler mission, launched last year, is hunting for alien moons, or exomoons and also scanning their atmospheres for key signs of life as we know it.
Lisa Kaltenegger is an astrophysicist at the Harvard-Smithsonian Center for Astrophysics. As she recently told Space.com, "If Pandora existed, we potentially could detect it and study its atmosphere in the next decade.” Further, we already know that the gas giants of our own solar system like Jupiter and Saturn have moons — there is no evidence to the contrary that the same would not hold true for alien planets and their own moons."
So far, the Kepler space telescope has found several Jupiter-sized gas objects in a range of orbits around their stars. While these planets cannot serve as a source of life, some feel that some rocky moons orbiting gas giants could in fact be friendly to life. Life could exist if that planet orbits within the star's region to create conditions warm enough for liquid water to exist on the surface. Scientists would also need to look for water, oxygen, carbon dioxide and methane on an Earth-like moon.
Kaltenegger explains it best. "All of the gas giant planets in our solar system have rocky and icy moons," Kaltenegger said. "That raises the possibility that alien Jupiters will also have moons. Some of those may be Earth-sized and able to hold onto an atmosphere."
However, the gas giants like Jupiter might not be the best hosts for life moons. Rather, the small, dim, red dwarf stars may be better targets when looking for life. The habitable zone for a red dwarf is closer to the star, which increases the chances of spotting an exoplanet's transit. But gravity could considerably hinder life. The moon would have to be tidally locked to the planet (as ours is) and not to the star. Further, plant life would have to have an energy source moon-wide.
Further, the moon would have to have a magnetosphere to protect it from tides that are too strong. Kaltenegger points out that Ganymede is the largest moon in our solar system with a magnetosphere. Tides on such moons would be very strong — "probably a surfer's paradise," Kaltenegger said.
Flying dragons aside, scientists point out that life on such a moon could be as fantastic as those depicted in Avatar. As Kaltenegger notes, “you've opened up the opportunity for habitats that can be completely new, fascinatingly different and potentially very weird."