Scientists with NASA's Cassini-Huygens mission have been tracking the visibly bright, lightning-generating storm--the longest continually observed electrical storm ever monitored by Cassini.
Saturn's electrical storms resemble terrestrial thunderstorms, but on a much larger scale. Storms on Saturn have diameters of several thousand kilometers (thousands of miles), and radio signals produced by their lightning are thousands of times more powerful than those produced by terrestrial thunderstorms.
Lightning flashes within the persistent storm produce radio waves called Saturn electrostatic discharges, which the radio and plasma wave science instrument first detected on Nov. 27, 2007. Cassini's imaging cameras monitored the position and appearance of the storm, first spotting it about a week later, on Dec. 6.
"The electrostatic radio outbursts have waxed and waned in intensity for five months now," said Georg Fischer, an associate with the radio and plasma wave science team at the University of Iowa, Iowa City. "We saw similar storms in 2004 and 2006 that each lasted for nearly a month, but this storm is longer-lived by far. And it appeared after nearly two years during which we did not detect any electrical storm activity from Saturn."
The new storm is located in Saturn's southern hemisphere--in a region nicknamed "Storm Alley" by mission scientists--where the previous lightning storms were observed by Cassini. "In order to see the storm, the imaging cameras have to be looking at the right place at the right time, and whenever our cameras see the storm, the radio outbursts are there," said Ulyana Dyudina, an associate of the Cassini imaging team at the California Institute of Technology in Pasadena, Calif.
Cassini's radio plasma wave instrument detects the storm every time it rotates into view, which happens every 10 hours and 40 minutes, the approximate length of a Saturn day. Every few seconds the storm gives off a radio pulse lasting for about a tenth of a second, which is typical of lightning bolts and other electrical discharges. These radio waves are detected even when the storm is over the horizon as viewed from Cassini, a result of the bending of radio waves by the planet's atmosphere.
Amateur astronomers have kept track of the storm over its five-month lifetime. "Since Cassini's camera cannot track the storm every day, the amateur data are invaluable," said Fischer. "I am in continuous contact with astronomers from around the world."
The long-lived storm will likely provide information on the processes powering Saturn's intense lightning activity. Cassini scientists will continue to monitor Storm Alley as the seasons change, bringing the onset of autumn to the planet’s southern hemisphere.
Color images of the storm are available at
http://ciclops.org .
Source: NASA
Related stories:
Physicist speaks at AAAS symposium about space weather
Most people leave home without checking the space weather report. But if New Jersey physicist Louis J. Lanzerotti, PhD, distinguished research professor at New Jersey Institute of Technology (NJIT), has his way, they won't leave home without it.
Cassini cameras spot powerful new lightning storm on Saturn
Following the recent detection of Saturnian radio bursts by NASA's Cassini spacecraft that indicated a rare and powerful atmospheric storm, Cassini imaging scientists have spotted the storm in an unlikely fashion: they looked for it in the dark.
Saturn’s aurora – not as we thought! Comment from UK scientists
Results which combine data from the joint NASA/ESA/ASI Cassini Huygens space mission and the Hubble Space Telescope, published in Nature today (17th February 2005), reveal that Saturn’s auroras, long thought to be a cross between those of Earth and Jupiter, are in fact different and may even be unique to Saturn.
Saturn’s radio emissions and bright auroras are linked
Just as the static on an AM radio grows louder with the approach of a summer lightning storm, strong radio emissions accompany bright auroral spots -- similar to Earth’s northern lights -- on the planet Saturn, according to a research paper published in the Thursday, Feb. 17 issue of the journal Nature.
Saturn's Aurora Defy Scientists' Expectations
Aurora on Saturn behave in ways different from how scientists have thought possible for the last 25 years, according to new research by a team of astronomers led by John Clarke, a professor in BU’s Department of Astronomy and in the department’s Center for Space Physics. The team’s findings have overturned theories about how Saturn’s magnetosphere behaves and how its aurora are generated. Their results will be published in the February 17 issue of Nature.
Researchers present Cassini findings at Saturn
NASA's Cassini spacecraft approached Saturn last July, it found evidence that lightning on Saturn is roughly one million times stronger than lightning on Earth. That's just one of several Cassini findings that University of Iowa Space Physicist Don Gurnett will present in a paper to be published Thursday, Dec. 16 in Science Express, an online version of the journal Science.
Cassini detects Lightning and Radiation at Saturn
Cassini justifies hopes.
The
Cassini spacecraft, which began its tour of the Saturn system just over a month ago, has detected lightning and a new radiation belt at Saturn, and a glow around the planet's largest moon, Titan.
Phoenix Mars Lander Ready to Gather Samples
Two practice rounds of digging and dumping the clumpy soil at the Martian arctic site this week gave scientists and engineers gathered at the University of Arizona confidence to begin using Phoenix's Robotic Arm to deliver soil samples to instruments on the lander deck.
