Space

December 6, 2013

NASA’s Cassini Spacecraft obtains best views of Saturn Hexagon

NASA’s Cassini spacecraft has obtained the highest-resolution movie yet of a unique six-sided jet stream, known as the hexagon, around Saturn’s north pole.

This is the first movie of its kind, using color filters, and the first to show a complete view of the top of Saturn down to about 70 degrees latitude. Spanning about 20,000 miles across, the hexagon is a wavy jet stream of 200-mph winds with a massive, rotating storm at the center. There is no weather feature exactly, consistently like this anywhere else in the solar system.

“The hexagon is just a current of air, and weather features out there that share similarities to this are notoriously turbulent and unstable,” said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena. “A hurricane on Earth typically lasts a week, but this has been here for decades – and who knows – maybe centuries.”

Weather patterns on Earth are interrupted when they encounter friction from land forms or ice caps. Scientists suspect the stability of the hexagon has something to do with the lack of solid land forms on Saturn, which is essentially a giant ball of gas.

Better views of the hexagon are available now because the sun began to illuminate its interior in late 2012. Cassini captured images of the hexagon over a 10-hour time span with high-resolution cameras, giving scientists a good look at the motion of cloud structures within.

They saw the storm around the pole, as well as small vortices rotating in the opposite direction of the hexagon. Some of the vortices are swept along with the jet stream as if on a racetrack. The largest of these vortices spans about 2,200 miles, or about twice the size of the largest hurricane recorded on Earth.

Scientists analyzed these images in false color, a rendering method that made it easier to distinguish differences among the types of particles suspended in the atmosphere – relatively small particles that make up haze – inside and outside the hexagon.

“Inside the hexagon, there are fewer large haze particles and a concentration of small haze particles, while outside the hexagon, the opposite is true,” said Kunio Sayanagi, a Cassini imaging team associate at Hampton University in Virginia. “The hexagonal jet stream is acting like a barrier, which results in something like Earth’s Antarctic ozone hole.”

The Antarctic ozone hole forms within a region enclosed by a jet stream with similarities to the hexagon. Wintertime conditions enable ozone-destroying chemical processes to occur and the jet stream prevents a resupply of ozone from the outside. At Saturn, large aerosols cannot cross into the hexagonal jet stream from outside and large aerosol particles are created when sunlight shines on the atmosphere. Only recently, with the start of Saturn’s northern spring in August 2009, did sunlight begin bathing the planet’s northern hemisphere.

“As we approach Saturn’s summer solstice in 2017, lighting conditions over its north pole will improve, and we are excited to track the changes that occur both inside and outside the hexagon boundary,” said Scott Edgington, Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

A black-and-white version of the imaging camera movie and movies obtained by Cassini’s visual and infrared mapping spectrometer also are tools Cassini scientists can use to look at wind speeds and the mini-storms inside the jet stream.

Cassini launched in 1997 and arrived at Saturn on July 1, 2004. Its mission is scheduled to end in September 2017. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA’s Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team is based at the Space Science Institute, Boulder, Colo.

The movies are available online at http://go.usa.gov/Wtrk.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines July 23, 2014

News: Israel’s Iron Dome defense in line for tripled U.S. spending - Israel’s iron Dome missile defense system may end up getting triple the U.S. funding that the Defense Department sought for it in March. Ukraine asked U.S. for systems to counter Russian missiles - A month before the United States says a Russian missile likely brought...
 
 

News Briefs July 23, 2014

U.S. military deaths in Afghanistan at 2,194 As of July 22, 2014, at least 2,194 members of the U.S. military had died in Afghanistan as a result of the U.S.-led invasion of Afghanistan in late 2001, according to an Associated Press count. The AP count is three less than the Defense Department’s tally. At least...
 
 
Raytheon photograph

Raytheon completes key Air, Missile Defense Radar reviews

Raytheon photograph Partially-populated, full-sized Air and Missile Defense Radar array. Raytheon has completed two critical program reviews for the new Air and Missile Defense Radar, the U.S. Navy’s next generation integ...
 

 
Insitu photograph

Insitu demonstrates long endurance capabilities of Integrator unmanned aircraft

Insitu photograph Insitu’s Integrator unmanned aircraft recovers via SkyHook; the aircraft recently completed a 24-hour endurance flight. Insitu announced July 22 the successful 24-hour flight of its Integrator unmanned a...
 
 

NASA partners punctuate summer with spacecraft development advances

Spacecraft and rocket development is on pace this summer for NASA’s aerospace industry partners for the agency’s Commercial Crew Program as they progress through systems testing, review boards and quarterly sessions under their† Space Act Agreements with the agency. NASA engineers and specialists continue their review of the progress as the agency and partners move...
 
 

U.S. Navy selects Northrop Grumman for ship self-defense system

The U.S. Navy has awarded Northrop Grumman a $12 million task order for a full range of engineering services to continue modernizing the Ship Self-Defense System Mark 2. The contract has a potential value of $61 million over five years, if all options are exercised. SSDS MK2 is a combat system designed for anti-air defense...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>