PIA 08410
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A bright, powerful, lightning-producing storm churns and coasts along the lane of Saturn’s southern hemisphere nicknamed “Storm Alley” by scientists. Cassini detected this particular tempest after nearly two years during which Saturn did not appear to produce any large electrical storms of this kind.
The storm appears as a bright, irregular splotch on the planet near lower right.
Lightning flashes within the persistent storm produce radio waves, called Saturn Electrostatic Discharges (SED), which the Cassini Radio and Plasma Wave Science (RPWS) instrument first detected on Nov. 27, 2007. Cassini’s imaging cameras then spotted the storm, taking the images used to create this color view about a week later on Dec. 6.
This electrical storm is similar in appearance and intensity to those previously monitored by Cassini. All of these powerful SED-producing storms appeared at about 35 degrees south latitude on Saturn. (See PIA07788, PIA08142 and PIA06197 for additional images of Saturn's electrical storms imaged by Cassini.)
This storm has now been continuously tracked by Cassini for several months, whereas previous storms observed by the spacecraft lasted for less than 30 days: See PIA08411 for images of the storm acquired three months after this view.
The view looks toward the unilluminated side of the rings from about 5 degrees above the ringplane. Tethys (1,071 kilometers, 665 miles across) is seen here in the foreground, and casts its shadow onto the high northern latitudes.
Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were acquired with the Cassini spacecraft wide-angle camera at a distance of approximately 1.7 million kilometers (1 million miles) from Saturn. Image scale is 97 kilometers (60 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. The radio and plasma wave science team is based at the University of Iowa, Iowa City.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org. The radio and plasma wave science instrument team home page is at: http://www-pw.physics.uiowa.edu/plasma-wave/cassini/home.html.
Credit: NASA/JPL/Space Science Institute
Released: April 29, 2008 (PIA 08410)
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If I'm not wrong in the 30's of the past century, a white spot was seen in Saturn. That spot increased until it enveloped the entire planet before disappearing. I'm not sure if it was a storm or a huge helium bubble that appeared from the deepness of Saturn; anyway, imagine if that happened again and Cassini was there to imaging it.
Hello, Andrew.
I would say there is not much doubt about water ice particles, though there is ammonia on Jupiter and Saturn to precipitate as well as water. It may play a role. Lightning on Uranus and Neptune is not detected but expected.
There is definitely the uncertainty about convection and observing lightning on the night side of Jupiter turns out to be a great tool in figuring out were the convection occurs.
On Saturn strong updrafts shown in the figures above appear to be stronger and way less frequent than on Jupiter. The power is hard to compare because on Jupiter we estimate the optical power and have no radio data, and on Saturn there is no optical data but there is radio detections to estimate the power.
And yes the updrafts are probably higher on Saturn.
Hi ulyana,
There would be no doubt that the lightning in all four of the outer planets (Jupiter to Neptune) is generated by the charge generated though ice crystals, as on Earth.
The uncertainty lies with the exact mechanism of how internal heat particularly with Jupiter, Saturn & Neptune convects the atmosphere & the relationships with the ice & other compounds, how they may contribute to lightning generation. Almost certainly Jupiter, Saturn, Uranus & Neptune have rain, snow & hail, possibly giant hail (I saw something once that suggested that Jupiter, Saturn & Neptune could have hailstones the size of footballs, don't know if that is still thought to be so).
The Galileo spacecraft saw thunderheads rise 50 KM or more above the general cloud deck in Jupiter's atmosphere. Don't know about Saturn, although with Saturn, the thunderheads should rise even higher due to the much weaker gravity, unbless the updraghts are weaker than Jupiter's.
Andrew Brown.
The mechanism of lightning generation on Saturn and Jupiter is not completely understood. However both planets are expected to have water clouds, which are the best candidates for lightning generation. If this is the case, lightning generation should be similar to the one in terrestrial thunderstorms - by separation of charges carried by hail, rain, and ice particles falling down at different speeds.
Great stuff. It seems the famous "Dragon Storm" has returned.
