For centuries, this great electrical storm never truly stopped. But then, in 2010, something unimaginable happened: The Catatumbo lightning went ... of the Pacific Ocean. Every few years, this ...

sending the moon into a stable orbit. Neither would have lost too much of its original material in the process. The incident could have created enough heat for Pluto to form an underground ocean ...

But evidence for Callisto's subsurface ocean has remained inconclusive, as the moon has an intense ionosphere. Scientists thought this electrically conductive upper part of the moon's atmosphere ...

“What we’ve done is put forth a strong case for an ocean,” study coauthor David Stevenson ... higher than they would expect from an empty depression covered by the moon’s planet-wide ice sheet. “Then ...