Ben Shoemate's Notebook

NASA’s Cassini spacecraft eavesdropped on a storm on Saturn on March 15, 2011, by capturing pulses of radio waves from the lightning strikes, and sent back audio of the event.

First spied by amateurs in early December, this storm is the largest and most powerful to be observed in detail. Once spotted the storm grew dramatically, from 2,500 km across on the first day to 17,000 three weeks later, with a tail sweeping around the entire planet.

Instruments aboard Cassini recorded lightning strikes as fast as 10 per second, too fast for the spacecraft’s radio and plasma wave instrument to easily separate into individual signals. The team created this sound file from radio waves emanating from the storm on March 15, during a relatively calm period. The 11-second clip contains data gathered over 57 seconds.

Two teams of researchers describe the storm’s churnings in this week’s Nature. Storms large enough to be spotted by Earth-bound telescopes, occur on Saturn about once every 30 years and are dubbed Great White Spots — a play on Jupiter’s Great Red Spot.

Image: False-color images from NASA’s Cassini spacecraft of the huge storm raging on Saturn. (NASA/JPL-Caltech/Space Science Institute).

An enormous storm has erupted in Saturn’s northern hemisphere.

Amateurs first sighted the storm earlier this month, but the Cassini spacecraft moved into a good position on Dec. 24 to photograph it from about 1.1 million miles away. Earth received the raw and unprocessed shots today.

The storm has a huge central funnel and a long tail that sweeps around Saturn’s northern hemisphere for tens of thousands of miles. A shot in blue light (left) reveals the extent of the tail, but infrared light (right) shows detail of the storm’s amorphous core. The photos were taken exactly a month after Cassini recovered from a solar-flare-induced error that temporarily silenced the spacecraft from Nov. 2 through Nov. 24.

Saturn’s weather is complex like Jupiter’s, but it’s often difficult to see such storms beneath Saturn’s hazy outer atmosphere, wrote Carolyn Porco, a planetary scientist and leader of Cassini’s imaging team, on Twitter.

Images: NASA/JPL/Space Science Institute

See Also:

• This Summer’s Sexiest Images From Saturn
• Video: Two Full Days of Saturn’s Aurora
• Red in Jupiter’s Spot Not What Astronomers Thought
• Cassini Spacecraft Spots New Object in Saturn’s Rings
• NASA: Cassini Camera Will Be Offline Until Nov. 24