Featured Research

from universities, journals, and other organizations

Looking deep into a huge storm on Saturn

Date:
May 19, 2011
Source:
ESO
Summary:
The atmosphere of the planet Saturn normally appears placid and calm. But about once per Saturn year (about thirty Earth years), as spring comes to the northern hemisphere of the giant planet, something stirs deep below the clouds that leads to a dramatic planet-wide disturbance. This is only the sixth of these huge storms to be spotted since 1876. It is the first ever to be studied in the thermal infrared -- to see the variations of temperature within a Saturnian storm -- and the first ever to be observed by an orbiting spacecraft.

Thermal infrared images of Saturn from the VISIR instrument on ESO's VLT (center and right) and an amateur visible-light image (left) from Trevor Barry (Broken Hill, Australia) obtained on Jan. 19, 2011, during the mature phase of the northern storm. The second image is taken at a wavelength that reveals the structures in Saturn's lower atmosphere, showing the churning storm clouds and the central cooler vortex. The third image is sensitive to much higher altitudes in Saturn's normally peaceful stratosphere, where we see the unexpected beacons of infrared emission flanking the central cool region over the storm.
Credit: ESO/University of Oxford/L. N. Fletcher/T. Barry

The atmosphere of the planet Saturn normally appears placid and calm. But about once per Saturn year (about thirty Earth years), as spring comes to the northern hemisphere of the giant planet, something stirs deep below the clouds that leads to a dramatic planet-wide disturbance.

Related Articles


The latest such storm was first detected by the radio and plasma wave science instrument on NASA's Cassini spacecraft [1], in orbit around the planet, and also tracked by amateur astronomers in December 2010. It has now been studied in detail using the VISIR [2] infrared camera on ESO's Very Large Telescope (VLT) in conjunction with observations from the CIRS instrument [3] on Cassini.

This is only the sixth of these huge storms to be spotted since 1876. It is the first ever to be studied in the thermal infrared -- to see the variations of temperature within a Saturnian storm -- and the first ever to be observed by an orbiting spacecraft.

"This disturbance in the northern hemisphere of Saturn has created a gigantic, violent and complex eruption of bright cloud material, which has spread to encircle the entire planet," explains Leigh Fletcher (University of Oxford, UK), lead author of the new study. "Having both the VLT and Cassini investigating this storm at the same time gives us a great chance to put the Cassini observations into context. Previous studies of these storms have only been able to use reflected sunlight, but now, by observing thermal infrared light for the first time, we can reveal hidden regions of the atmosphere and measure the really substantial changes in temperatures and winds associated with this event."

The storm may have originated deep down in the water clouds where a phenomenon similar to a thunderstorm drove the creation of a giant convective plume: just as hot air rises in a heated room, this mass of gas headed upwards and punched through Saturn's usually serene upper atmosphere. These huge disturbances interact with the circulating winds moving east and west and cause dramatic temperature changes high up in the atmosphere.

"Our new observations show that the storm had a major effect on the atmosphere, transporting energy and material over great distances, modifying the atmospheric winds -- creating meandering jet streams and forming giant vortices -- and disrupting Saturn's slow seasonal evolution," adds Glenn Orton (Jet Propulsion Laboratory, Pasadena, USA), another member of the team.

Some of the unexpected features seen in the new imaging from VISIR have been named stratospheric beacons. These are very strong temperature changes high in the Saturnian stratosphere, 250-300 km above the cloud tops of the lower atmosphere, that show how far up into the atmosphere the effects of the storm extend. The temperature in Saturn's stratosphere is normally around -130 degrees Celsius at this season but the beacons are measured to be 15-20 degrees Celsius warmer.

The beacons are completely invisible in reflected sunlight but can outshine the emission from the rest of the planet in the thermal infrared light detected by VISIR. They had never been detected before, so astronomers are not sure if they are common features in such storms.

"We were lucky to have an observing run scheduled for early in 2011, which ESO allowed us to bring forward so that we could observe the storm as soon as possible. It was another stroke of luck that Cassini's CIRS instrument could also observe the storm at the same time, so we had imaging from VLT and spectroscopy of Cassini to compare," concludes Leigh Fletcher. "We are continuing to observe this once-in-a-generation event."

Notes

[1] The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, California, a division of the California Institute of Technology, manages the mission for NASA's Science Mission Directorate, Washington, DC.

[2] VISIR is the VLT spectrometer and imager for the mid-infrared. VISIR was built by CEA/DAPNIA/SAP and NFRA/ASTRON.

[3] CIRS stands for Composite Infrared Spectrometer, one of the instruments on Cassini. CIRS analyses heat radiation and is capable of discerning an object's composition.


Story Source:

The above story is based on materials provided by ESO. Note: Materials may be edited for content and length.


Journal Reference:

  1. Leigh N. Fletcher, Brigette E. Hesman, Patrick G. J. Irwin, Kevin H. Baines, Thomas W. Momary, A. Sanchez-Lavega, F. Michael Flasar, P. L. Read, Glenn S. Orton, Amy Simon-Miller, Ricardo Hueso, Gordon L. Bjoraker, A. Mamoutkine, Teresa Del Rio-Gaztelurrutia, Jose M. Gomez, Bonnie Buratti, Roger N. Clark, Philip D. Nicholson, and Christophe Sotin. Thermal Structure and Dynamics of Saturn’s Northern Springtime Disturbance. Science, 19 May 2011 DOI: 10.1126/science.1204774

Cite This Page:

ESO. "Looking deep into a huge storm on Saturn." ScienceDaily. ScienceDaily, 19 May 2011. <www.sciencedaily.com/releases/2011/05/110519141617.htm>.
ESO. (2011, May 19). Looking deep into a huge storm on Saturn. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2011/05/110519141617.htm
ESO. "Looking deep into a huge storm on Saturn." ScienceDaily. www.sciencedaily.com/releases/2011/05/110519141617.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Space & Time News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Spokesman: 'NORAD Ready to Track Santa'

Spokesman: 'NORAD Ready to Track Santa'

AP (Dec. 19, 2014) Pentagon spokesman Rear Adm. John Kirby said that NORAD is ready to track Santa Claus as he delivers gifts next week. Speaking tongue-in-cheek, he said if Santa drops anything off his sleigh, "we've got destroyers out there to pick them up." (Dec. 19) Video provided by AP
Powered by NewsLook.com
NASA's Planet-Finding Kepler Mission Isn't Over After All

NASA's Planet-Finding Kepler Mission Isn't Over After All

Newsy (Dec. 18, 2014) More than a year after NASA declared the Kepler spacecraft broken beyond repair, scientists have figured out how to continue getting useful data. Video provided by Newsy
Powered by NewsLook.com
Rover Finds More Clues About Possible Life On Mars

Rover Finds More Clues About Possible Life On Mars

Newsy (Dec. 17, 2014) NASA's Curiosity rover detected methane on Mars and organic compounds on the surface, but it doesn't quite prove there was life ... yet. Video provided by Newsy
Powered by NewsLook.com
Evidence of Life on Mars? NASA Rover Finds Methane, Organic Chemicals

Evidence of Life on Mars? NASA Rover Finds Methane, Organic Chemicals

Reuters - US Online Video (Dec. 16, 2014) NASA's Mars Curiosity rover finds methane in the Martian atmosphere and organic chemicals in the planet's soil, the latest hint that Mars was once suitable for microbial life. Linda So reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins