In the search for an Earth-like alien world, astronomers have had their eyes set on planets beyond our solar system, but some moons orbiting these exoplanets may be just as likely to support life, scientists say.
Astronomers have discovered more than 800 exoplanets, with many more candidate worlds awaiting confirmation by follow-up observations. Most of them, however, are gas giants, similar to Jupiter, and only a handful have a solid surface and orbit their host stars in the habitable zone (the range where liquid water, and perhaps life as we know it, can exist).
But a team of astronomers says these uninhabitable exoplanets could host habitable exomoons.
Though no habitable exomoons have been found, Barnes and René Heller of Germany’s Leibniz Institute for Astrophysics Potsdam say there’s no reason to assume they don’t exist.
Some researchers have already started thinking about how they might use instruments like the planet-hunting Kepler Space Telescope to detect alien moons. Telescopes such as Kepler search for planets as they transit, or cross in front of, their star, causing telltale dips in the star’s brightness. Variations in these brightness patterns might reveal the presence of a moon orbiting a planet.
Next up: Getting there will be half the fun.