Cassini Spacecraft Images and Sounds of Saturn Super Storm
From NASA: PASADENA, Calif. – Scientists analyzing data from NASA’s Cassini spacecraft now have the first-ever, up-close details of a Saturn storm that is eight times the surface area of Earth.
“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.“
On Dec. 5, 2010, Cassini first detected the storm that has been raging ever since. It appears at approximately 35 degrees north latitude on Saturn. Pictures from Cassini’s imaging cameras show the storm wrapping around the entire planet covering approximately 1.5 billion square miles (4 billion square kilometers).
The storm is about 500 times larger than the biggest storm previously 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.”
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.
Scientists are excited by the storm because it provides further insight into the weather patterns of the planet. Apparently this occurrence shows just how much the change of seasons can affect the planet’s major weather.
You can download a short audio from NASA JPL, from the saturn super storm lightning taken place. This offers some impression of the magnitude of lightning strikes occurring in the vicinity of the storm.
Lightning at Saturn creates phenomena known as Saturn electrostatic discharges, which are like the static that Earth lightning creates on an AM radio. The amplitude and duration of the Saturn lightning radio signals were used to create the audio signals heard here. At its most active, lightning flashes occurred at a rate of more than 10 per second. This was so frequent, in fact, that Cassini could no longer resolve individual strokes. On March 15, when these data were collected, the strike intensity was slightly lower and easier to resolve.
This lightning storm is also remarkable in that it is the first Cassini has observed in Saturn’s northern hemisphere, suggesting that these storms break out when spring and summer come to a particular hemisphere. Spring began in the northern hemisphere in August 2009, when the sun moved from shining over the southern hemisphere to the northern one.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency (ASI).