Add Yahoo as a preferred source to see more of our stories on Google. Some 'water worlds' like Jupiter's moon Europa could potentially be habitable for life. NASA/JPL-Caltech/SETI Institute The search ...

Astronomers have, for the first time, pinned down both the mass and distance of a planet that drifts through the galaxy without a parent star, turning a once purely theoretical class of worlds into a ...

More than 10 years after the discovery of the first extrasolar planet, astronomers have now discovered more than 250 of these planets. Until a few years ago, most of the newly discovered exoplanets ...