Last December amateur and professional astronomers identified a swirling smudge on the gaseous surface of Saturn, and a few months later NASA scientists got a good look at one of the largest storms ever observed. At nearly two billion square miles—eight times the surface of Earth—and 186,000 miles long, the intense storm grew to nearly encircle the planet. Ribbons of clouds likely consisted of ice covered by crystallized ammonia and produced stunning views for a camera aboard the Saturn orbiter Cassini.
Researchers note that this storm was particularly violent, spewing deep plumes of atmospheric materials in its wake and billowing up through the highest levels of the stratosphere. At one point, it produced a 3,000-mile-wide vortex at its core. “Nothing on Earth comes close,” says Leigh Fletcher, a Cassini team scientist at the University of Oxford, and even on Saturn “a storm like this is rare.”
Since its launch in 1997, Cassini has captured 10 electrical storms on Saturn’s surface, though this one is 500 times larger than one observed in 2009. It’s “thrilling,” says Georg Fischer, a radio and plasma wave science team member at the Austrian Academy of Sciences in Graz, “because it shows how shifting seasons and solar illumination can dramatically stir up the weather on Saturn.”
