Tuesday, March 20, 2018

Giant Cyclones Dot Jupiter’s Poles

Credit: NASA/SwRI/MSSS/Gerald Eichstädt /John Rogers

Large cyclones have been discovered clustered around Jupiter’s poles by NASA’s Juno spacecraft. The circumpolar cyclones were discovered on Juno’s first pass over Jupiter’s poles, and subsequent data has revealed how remarkably stable they are. The circumpolar cyclones ring a single cyclone at each pole.

Using visible images from NASA’s JunoCam camera headed by Planetary Science Institute Senior Scientist Candice Hansen, and infrared images obtained by the spacecraft’s Jovian Infrared Auroral Mapper (JIRAM), researchers found eight circumpolar cyclones arranged around a single Northern polar cyclone and five circumpolar cyclones encircling a Southern polar cyclone. 

“Jupiter's circumpolar cyclones are unique; the polar regions are unlike any of the other gas giants,” said Hansen, JunoCam instrument lead and Juno Co-Investigator. “The circumpolar cyclones in the north are as big as the continental United States. The cyclones in the south are even larger. 

“And they are surprisingly stable. They are identifiable from one close pass to the next, with a 53 day separation, and they are in a very stable configuration – no new ones have spun up, no old ones have dissipated,” she said. 

Wind speeds measured 580 miles from the center of these giant storms range from 100 mph to 220 mph, she said. 

When Juno flies over Jupiter’s poles only half the planet is in sunlight – the other half is in the dark of night. For this reason, to see the clouds in the entire south polar region, images from Juno’s first and fourth close passes are combined in this illustration. The combined image clearly shows a set of five circumpolar cyclones arranged in a pentagon around the polar cyclone approximately in the middle of this picture. Farther from the poles cyclonic and anticyclonic storms swirl around in a turbulent region unlike the familiar stripes of Jupiter’s belts and zones.

Credit: psi.edu

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