Mega-storm churns up Saturn

Posted by Kate Taylor

NASA's Cassini spacecraft has been watching the aftermath of the largest and hottest stratospheric vortex ever detected in our solar system.

The storm sent the temperature in Saturn's stratosphere soaring 150 degrees Fahrenheit above normal. At the same time, NASA researchers detected a huge increase in the amount of ethylene gas, the origin of which is a mystery.

"This temperature spike is so extreme it's almost unbelievable, especially in this part of Saturn's atmosphere, which typically is very stable," says Brigette Hesman, a University of Maryland scientist who works at NASA's Goddard Spaceflight Center.

"To get a temperature change of the same scale on Earth, you'd be going from the depths of winter in Fairbanks, Alaska, to the height of summer in the Mojave Desert."

First detected by Cassini in Saturn's northern hemisphere on December 5, 2010, the storm was the largest in over a century - so large that it could wrap around Earth several times. Initially, it was larger than Jupiter's Great Red Spot.

The huge spike of ethylene detected by NASA peaked with 100 times more ethylene than scientists had ever thought possible for Saturn. The team is trying to work out where it came from, but has ruled out a large reservoir deep in the atmosphere.

"We've really never been able to see ethylene on Saturn before, so this was a complete surprise," said Goddard's Michael Flasar, the CIRS team lead.

The team also observed a powerful ring of clockwise winds - encompassing a 'bizarre soup' of gases - around the vortex.

"These studies will give us new insight into some of the photochemical processes at work in the stratospheres of Saturn, other giants in our solar system, and beyond," says Scott Edgington, Cassini deputy project scientist at NASA's Jet Propulsion Laboratory.