Infrared Images of Saturn’s Poles

NASA’s Cassini spacecraft has taken new pictures showing a giant cyclone at Saturn’s north pole and its south pole, the latter apparently powered by Earth-type storm patterns.

The characteristics of these cyclones differs from Earth-based cyclones in interesting ways.

The north pole cyclone is only visible in the near-infrared wavelengths due to winter in that region of Saturn. At these wavelengths, seven times greater than that of visible light, the clouds deep inside Saturn’s atmosphere are only seen in silhouette against the background radiation of Saturn’s internally generated heat.

Saturn's South Polar Region Revealed

An infrared map of the north pole of Saturn has been created showing features as small as 120 km (75 mi) visible. The whirlpool-like cyclone there is rotating at 530 km/hr (325 mph), more than twice as fast as the highest winds measured in cyclones on Earth.

This cyclone is surrounded by a honeycombed-shaped hexagon, which itself does not seem to move while the clouds within it whip around at high speeds, also greater than 500 km/hr (300 mph). Neither the fast-moving clouds inside the hexagon nor this new cyclone seem to disrupt the six-sided hexagon.

Hurricanes on Earth are fueled by the ocean’s heat and water while Saturn’s cyclones have no body of water at their bases as Saturn’s hurricanes are locked to the planet’s poles, whereas terrestrial hurricanes drift across the ocean.

Just as condensing water in clouds on Earth powers hurricane vortices, the heat released from the condensing water in Saturn’s thunderstorms deep down in the atmosphere may be the primary power source energizing the vortex.

At the southern pole, the new infrared images of the pole, under the daylight conditions of southern summer, show the entire region is marked by hundreds of dark cloud spots. The Yet Yawning Gulf

The clouds, like those at the north pole, are likely composed of ammonium hydro-sulfide with possibly a mixture of other materials from below. Conversely, most of the hazes and clouds seen on Saturn are believed to be composed of ammonia, which condenses at higher and more visible altitudes.

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The pictures that Cassini takes of Saturn and its moons continue to be phenomenal.

The Cassini spacecraft took this photo of Saturn’s moon, Tethys, 15 degrees above Saturn’s ringplane. It’s quite a contrast when you consider the fact that Tethys is 1,062 km, or 660 miles in diameter while Saturn is 60,268 km, or 37,200 miles wide.

Tethys 06.11.08

This image utilized visible red light with Cassini’s wide-angle camera. Taken on May 13, 2008, the spacecraft was 1.3 million km, or 836,000 miles from Saturn.

NASA is extending the international Cassini-Huygens mission by two years. Originally scheduled to end in July of this year, planned projects are: twenty-six flybys of Titan, seven of Enceladus, one each of Dione, Helene, and Rhea, and further studies of Saturn’s rings, magnetosphere and planetary environment.

Saturn Moon Collage

This is really good news. It seems the spacecraft is operating well and is in good shape. There are three instruments that have ‘hiccups,’ not bad for having been launched ten years ago. There is still propellant available to carry out the maneuvers needed in the next two years. The discoveries and pictures just add to the mountain of questions and lists of items we would like to know more about.

Cassini has been providing data daily for the past four years. While operating costs are involved, chiefly in labor, all the equipment, a not insignificant cost, is working and paid for long ago. It actually saves money keep a mission going that yields scientific value. A second spacecraft can be delayed for some years that would entail much additional cost, a cost that can be avoided for a while by keeping Cassini “on the payroll.”. Plus Cassini is a proved success. This also helps ensure more focused and specific missions to Titan and Enceladus at some distant point in the future.

See NASA’s news release here: http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=833

PBS’s science show NOVA rebroadcast their excellent April 4, 2006 episode tonight about Titan, one of over 40 moons of Saturn. The show is very informative and has an associated web site that is just marvelous. An interview with Carolyn Porco regarding Enceladus, to coincide with the recent findings by the Cassini spacecraft that large reservoirs of liquid water lie beneath its southern pole, can be found here: Dr. Porco interview. Dr. Porco is the Cassini Imaging Team Leader. It is an interesting interview posing questions to her like: How is it possible on a world that has a surface temperature of -330 degrees F that water could be spewing out of the south pole? Good question and there is a good answer in the interview.

Enceladus, Saturn’s miniature ice moon, is shown below in this enhanced, colorized image spewing out the water laden ice particles like a geyser. The episode is titled “Voyage to the Mystery Moon” and here is the link to the show’s web page: Voyage to the Mystery Moon web page.Enceladus ice geyser A complete transcript to the entire show is at this link: http://www.pbs.org/wgbh/nova/transcripts/3309_titan.html .

Most of the show is about Titan. There is an interactive flash graphic about the rings of Saturn. The interactive displays the following questions:

1- How old are the rings; 2- How did they form; 3- What are they made of; 4- How many rings are there; 5- How vast are they; 6- Why do they lie in one plane; 7- What makes gaps in the rings; 8- What makes bright bands in the rings; 9- Are there moons within the rings; 10- Do the rings have an atmosphere; and, 11- How did Cassini pass through the rings?

Clicking on a question brings up graphics and a side bar with the explanation posed by the question. NOVA programs always have an associated web site to further the educational value of the show and they are always great sites. This particular site I found very nicely organized and informative especially in view of the recent flybys of Titan and Enceladus made by the Cassini spacecraft. There is also an article about how planets, or in the case of Titan, moons, get and acquire their own atmosphere.

The Cassini flyby of Enceladus on March 12 show tracks of heat running along giant fissures in the south polar region. As depicted in the graphic below, heat is radiating the length of the 150 km (95 mi) fractures. The chemistry of Enceladus heat radiationEnceladus resembles that of a comet, although it is definitely a moon, evidenced by the internally generated heat measured by the recent flyby.

The material encountered by Cassini coming up from the surface of Enceladus was much denser than expected, 20 times more so. Volatile gases, water vapor, carbon dioxide and carbon monoxide were components of the plumes Cassini flew through.

Temperatures measured along the fissures were at least minus 135 degrees Fahrenheit. This seems very cold to me but when one realizes how far from the Sun Enceladus is, its actually considered relatively warm. It’s 200 degrees Fahrenheit warmer than other places on Enceladus. Scientists believe these temperatures make it more likely there is water flowing beneath the surface of this moon of Saturn.

Observations indicate that four sources of heat send plumes jumping up from the surface. These individual plumes meet and come together, blending to form one large plume.  Future investigations will look at the sources of the individual plumes and the differences among the fissures.

Cassini was 30 miles from Enceladus at its closest approach during this flyby and 120 miles out when it flew through the plumes. The next flyby is planned for August.

Saturn's rings

The rings of Saturn never produce an un-awe- inspiring image.

The bright ring in the middle is the B ring, caused by wake like features of the ring which reflect sunlight differently than the other rings, making it unusually bright. This image was taken about 574,000 km (357,000 mi) from Saturn by the Cassini-Huygens spacecraft.

For a very good image and annotation of Saturn’s rings that can be enlarged with a high resolution, see this link—  http://photojournal.jpl.nasa.gov/figures/PIA08389_fig1.jpg

Photo: NASA/JPL/Space Science Institute

Whenever I see pictures of Saturn’s rings, I’m (for some reason) reminded of the 1970’s song by Cymarron, a soft rock band. It seems an appropriate ode to rings. The lyrics are below.

Ring, ring, telephone rings
Somebody said, “Baby what you doin?”
I been wondering where you been
Now and then, I think about you and me
No use fightin’ ’bout things we can’t recall
It don’t matter now at all,
Just come on home
Baby we’ll laugh and sing
We’ll make love, we’ll let the telephone ring
‘Ring, ring, doorbell ring’
Baby come on in, got James Taylor on the stereo
I’m glad you’ve come around, I’ve been feelin’ down
Just talkin’ to Tony and Mario
You know they make good conversation,
Still it ain’t no consolation
Cause I got love, baby I’ll give you some
And if somebody comes, we’ll let the doorbell ring
Said ‘Ring, ring, golden rings
Around the sun, around your pretty finger’
‘Ring, ring, voices ring
With a happy tune, anybody can be a singer’
The sun come up across the city
I swear you never looked so doggone pretty
Hand in hand,
We’ll stand upon the sand
With the preacher man
Let the wedding bells ring
Oh-ohhh, hand in hand
We’ll stand upon the sand
Upon the sand
Upon the sand
With the preacher man
Let the wedding bells ring….
Ah-hhh

The Enceladus - NASA 03.13.08Cassini spacecraft survived the flyby, actually a fly-through of the ice-water plumes shooting out from the surface of Saturn’s moon, Enceladus. This is quite an accomplishment considering the fact that the speed of the water vapor particles in the plume were gushing up from the surface at 400 meters per second, or 800 mph.

Additionally, Cassini was speeding by at 15 km per second or 32,000 mph. Cassini picked up for analysis samples of the ice/water mixture shooting up from the surface of Enceladus.

Two instruments collecting data for analysis are the Cosmic Dust Analyzer and the Ion & Neutral Mass Spectrometer. The analysis will be looking for evidence of an Earth-like ocean of water and/or organic compounds inside the tiny moon that are not visible telescopically.

Specifically, Cassini’s particle analyzers dissected the “body” of the plume searching for information on the density, size, composition and velocity of the particles within it. The data should help determine whether the gasses in the plume match the halo of particles around Enceladus.

These geysers may originate from this ocean beneath the surface, spewing out from fractures along the south pole of Enceladus. The working assumption has been that water is trapped under the iced over crust of the moon. This flyby will provide a detailed view of these fractures and will enable a better comparison of geological history of the north and south poles.

New images show the north pole to be older as evidenced by the many craters in the north compared to the rarity of these in the south. These craters in the north have small parallel slices running through them, possibly from heating and cooling cycles and perhaps tectonic activity.

Cassini first discovered these geyser like jets in 2005, finding that the continuous eruption of the water vapor plumes create a gigantic halo of ice dust and gas around Enceladus. Much of this material is eventually drawn into Saturn’s E-ring due to its proximity to Enceladus.

Another flyby will occur in August and another in October of this year. Cassini’s mission was scheduled to end this June, however, it has been extended. Cassini will make up to seven more flybys of Enceladus. Recent news and more pictures regarding Cassini’s mission can be found at the NASA web site for Cassini here.