Data analysis of NASA's Cassini spacecraft by scientists has revealed the first-ever, up-close details of a Saturn storm that is eight times the surface area of Earth, NASA's official website said.

Cassini first detected the storm on Decomber 5, 2010 and the storm has been raging ever since.

The storm appears at approximately 35 degrees north latitude on Saturn. Pictures from Cassini's cameras show the storm wrapping around the entire planet covering approximately 1.5 billion square miles (4 billion square kilometers).

This storm is approximately 500 times larger than the previously thought biggest storm seen by Cassini during several months from 2009 to 2010.

Scientists studied the sounds of the new storm's lightning strikes and analyzed images taken between December 2010 and February 2011. Data from Cassini's radio and plasma wave science instrument showed the lightning flash rate as much as 10 times more frequent than during other storms monitored since Cassini's arrival to Saturn in 2004. The data appear in a paper published this week in the journal Nature.

Cassini shows us that Saturn is bipolar, said Andrew Ingersoll, an author of the study and a Cassini imaging team member at the
California Institute of Technology in Pasadena, Calif. 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.

At its most intense, the storm generated more than 10 lightning flashes per second. Even with millisecond resolution, the spacecraft's radio and plasma wave instrument had difficulty separating individual signals during the most intense period. Scientists created a sound file from data obtained on March 15 at a slightly lower intensity period.

Cassini has 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. Those storms rolled through an area in the southern hemisphere dubbed Storm Alley. 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,
said Georg Fischer, the paper's lead author and a radio and plasma wave science team member at the Austrian Academy of Sciences in Graz. 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. During this effort, Cassini looks at likely storm locations on Saturn in between its scheduled observations. On the same day that the radio and plasma wave instrument detected the first lightning, Cassini's cameras happened to be pointed at the right location as part of the campaign and captured an image of a small bright cloud.

Because analysis on that image was not completed immediately, Fischer sent out a notice to the worldwide amateur astronomy community to collect more images. A flood of amateur images helped scientists track the storm as it grew rapidly, wrapping around the planet by late January 2011.

The new details about this storm complement atmospheric disturbances described recently by scientists using Cassini's composite infrared spectrometer and the European Southern Observatory's Very Large Telescope. The storm is the biggest observed by spacecraft orbiting or flying by Saturn. NASA's Hubble Space Telescope captured images in 1990 of an equally large storm.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena manages the mission for the agency's Science Mission Directorate in Washington. The radio and plasma wave science team is based at the University of Iowa, Iowa City, where the instrument was built. The imaging team is based at the Space Science Institute in Boulder, Colo.

Catching Its Tail
The huge storm churning through the atmosphere in Saturn's northern hemisphere overtakes itself as it encircles the planet in this true-color view from NASA’s Cassini spacecraft.This picture, captured on Feb. 25, 2011, was taken about 12 weeks after the storm began, and the clouds by this time had formed a tail that wrapped around the planet. Some of the clouds moved south and got caught up in a current that flows to the east (to the right) relative to the storm head. This tail, which appears as slightly blue clouds south and west (left) of the storm head, can be seen encountering the storm head in this view. Image credit: NASA/JPL-Caltech
A Day in the Life
These false-color images from NASA's Cassini spacecraft chronicle a day in the life of a huge storm that developed from a small spot that appeared 12 weeks earlier in Saturn's northern mid-latitudes.This storm is the largest and most intense observed on Saturn by NASA’s Voyager or Cassini spacecraft. The storm is still active. As seen in these and other Cassini images, the storm encircles the planet - whose circumference at these latitudes is 186,000 miles (300,000 kilometers). From north to south, it covers a distance of about 9,000 miles (15,000 kilometers), which is one-third of the way around the Earth. It encompasses an area of 1.5 billion square miles (4 billion square kilometers), or eight times the surface area of Earth. This storm is about 500 times the area of the biggest of the southern hemisphere storms (see PIA06197 and PIA12576) observed by Cassini. NASA/JPL-Caltech/SSI
Spotting Saturn039s Northern Storm
NASA's Cassini spacecraft captures a composite near-true-color view of the huge storm churning through the atmosphere in Saturn's northern hemisphere.This storm is the largest and most intense observed on Saturn by NASA's Voyager or Cassini spacecraft. The storm is still active. As scientists have tracked this storm over several months, they have found it covers 500 times the area of the biggest of the southern hemisphere storms observed earlier in the Cassini mission (see PIA06197 and PIA12576). The shadow cast by Saturn's rings has a strong seasonal effect, and it is possible that the switch to powerful storms now being located in the northern hemisphere is related to the change of seasons after the planet's August 2009 equinox. NASA/JPL-Caltech/SSI
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