The image: Since 2004, NASA's robotic Cassini spacecraft has been studying Saturn and its many icy moons. Researchers had long suspected that the sixth largest moon, Enceladus, was capable of causing aurora-like spots on Saturn's surface, but no evidence of the phenomenon had ever been recorded. But finally, a recent study published in Nature reveals that Cassini detected "a shimmering patch of light as big as Sweden" near Saturn's north pole. (See an artist's rendering below.) The "spectacular" swath of light is the result of an electrical circuit between Saturn and the moon. Electrons flow through Enceladus' poles and hit Saturn's magnetic field, leaving the moon's "auroral footprint" on the planet's surface.
The reaction: "This finding marks a great leap forward in our understanding of what exactly is going on at mysterious Enceladus," says the study's co-author, Dr. Geraint Jone, as quoted by Physorg.com. Indeed, we had always known this northern lights effect happened between Jupiter and several of its moons, says co-author Andrew Coates, as quoted by the Daily Mail. But now Saturn has joined the club, too. See for yourself: