Saturn SnowballGiant "snowballs" have been discovered plunging through Saturn's outermost ring, creating glittering trails of ice dubbed mini-jets, researchers have announced.The jets were uncovered in new images from NASA's Cassini orbiter, which has been touring the Saturnian system for the past seven years.The colliding snowballs are formed as material in Saturn's F ring coalesces due to the gravitational pull of the nearby moon Prometheus. Scientists estimate that the icy bodies, including the one seen above, are each about 0.62 mile (a kilometer) wide.(Also see "Ice 'Tsunamis' Detected in Saturn Ring.")Sometimes a snowball sails back through the F ring at a gentle clip of roughly 4 miles (6.4 kilometers) an hour, dragging along icy particles.The resulting jets "are about 10 kilometers [6.2 miles] wide and extend out from the rings anywhere from 40 to 180 kilometers [25 to 112 miles], depending on their age, with their lengths increasing dramatically over just a few hours," said Carl Murray, a Cassini imaging team member based at Queen Mary University in London, England."At any given time we might expect to see about ten of these if we looked all the way around the F ring."—Andrew Fazekas

Image courtesy Caltech/SSI/QMUL/NASA