One of Blighty's top exomoonologists has said that NASA's new "Kepler" space telescope - in addition to its hotly-anticipated ability to discover habitable planets orbiting other stars - will also be able to detect habitable moons orbiting the gas giants of far-flung solar systems.
David Kipping, an astronomer at University College London (UCL), specialises in the hunting of "exomoons", moons beyond our solar system. He and his colleagues' latest research indicates that NASA's new Kepler space telescope - or another of similar quality - should be capable of spotting even quite small moons, down to just 20 per cent of the mass of Earth.
Such moons might easily be found orbiting large gas giant planets in other star systems: if these gas planets lay within the liquid-water zone of their parent sun(s), the moons could well be habitable for Earth-style life - as depicted in some versions of the Star Wars universe, where the "forest moon of Endor" is occasionally shown in orbit around a gas giant. Moons orbiting a gas giant within a liquid-water zone are also one of the more credible ways that a star system might contain more than one inhabited body, so allowing such otherwise implausible concepts as interplanetary trade, warfare, conquest, etc.*
According to Kipping, who says that "exomoonology" is one of his primary interests:
Habitable-zone exomoons down to 0.2 Earth masses may be detected and ~25,000 stars could be surveyed for habitable-zone exomoons within Kepler's field-of-view. A Galactic Plane survey with Kepler-class photometry could potentially survey over one million stars for habitable-zone exomoons. In conclusion, we propose that habitable exomoons will be detectable should they exist in the local part of the galaxy.
If they aren't detected, then, we can safely assume that the galaxy is significantly more dull than one with inhabitable moons would be.
Kipping and his colleagues' paper, On the detectability of habitable exomoons with Kepler-class photometry, has been accepted for publication in the Monthly Notices of the Royal Astronomical Society. You can read it online already, though, here. ®
* Not that these wouldn't still tend to require spacecraft much more advanced than those of present-day Earth: but such activities would be hugely more achievable than interstellar interaction.