This artist's conception shows a hypothetical gas giant planet with an Earth-like moon similar to the moon Pandora in the movie Avatar. New research shows that, if we find such an "exomoon" in the habitable zone of a nearby star, the James Webb Space Telescope will be able to study its atmosphere and detect key gases like carbon dioxide, oxygen, and water. An alien moon orbiting the gas giant planet of a red dwarf star may actually be more likely to be habitable than tidally locked Earth-sized planets or super-Earths.
Credit: David A. Aguilar, CfA