NASA scientists have captured both the sight and sounds of a storm on Saturn that covers eight times the surface area of Earth.
Cassini first detected the storm at approximately 35 degrees north latitude in December last year, and it's been raging ever since. Cassini's imaging cameras show the storm wrapping around the entire planet, covering around 1.5 billion square miles.
It's about 500 times larger than the biggest storm previously seen by Cassini since 2009, and lightning is flashing 10 times more often than has been seen in other storms. At its most intense, the storm generated more than 10 lightning flashes per second.
"Cassini shows us that Saturn is bipolar," says team member Andrew Ingersoll. "Saturn is not like Earth and Jupiter, where storms are fairly frequent. Weather on Saturn appears to hum along placidly for years and then erupt violently. I'm excited we saw weather so spectacular on our watch."
Cassini's detected 10 lightning storms on Saturn since the spacecraft entered the planet’s orbit and its southern hemisphere was experiencing summer, with full solar illumination not shadowed by the rings. But the sun's illumination on the hemispheres flipped around August 2009, when the northern hemisphere began experiencing spring.
"This storm is thrilling because it shows how shifting seasons and solar illumination can dramatically stir up the weather on Saturn," says team member Georg Fischer.
"We have been observing storms on Saturn for almost seven years, so tracking a storm so different from the others has put us at the edge of our seats."
The storm's results are the first activities of a new Saturn Storm Watch campaign, whereby Cassini will monitor likely storm locations in between its scheduled observations.
There's an audio file of the storm, here.