Cassini Equinox & Solstice Mission, (nine year extension)!!.

[EarthlingX]

www.universetoday.com : Titan-ic Tsunami Causing Crack in Saturn’s C Ring

Oct 4th, 2010

by Nancy Atkinson


This graphic shows an angled view of a newly discovered “crack” in one of Saturn’s rings, known as the C ring. This view shows the 3-D quality of the puzzling crack associated with a wave-like feature that was discovered earlier by NASA’s Voyager 1 spacecraft. Image credit: NASA/JPL/Cornell

Saturn’s rings have several gaps, most of which are caused by small moons shepherding ring debris into breaks in the rocky rings. But one gap may be caused by gravitational perturbations from Saturn’s largest moon, Titan, sending tsunami-like waves up to 3 kilometers (2 miles) high in the C ring, causing it to spin like a warped, uneven vinyl record on a turntable. A new model of this action explains why the gap was narrower than expected and also why is seems to disappear from time to time. “What looked like a 15-kilometer-wide gap actually was this gap with a vertical displacement of about 3 kilometers projected and seen almost edge on,” said Phillip Nicholson from Cornell University, speaking at a press briefing at the American Astronomical Society’s Division for Planetary Sciences meeting in Pasadena, California. “It’s a little like a tsunami propagating away from an earthquake fault.”

...

The Cassini spacecraft looks close at Saturn to frame a view encompassing the entire C ring. Image credit: NASA/JPL/SSI

...

Nicholson said only when they began to think in three dimensions were they able to solve the mystery of this gap. While most of Saturn’s rings are flat, in 2009, the angle of sunlight during Saturn’s spring equinox revealed there were lumps and bumps in the rings are as high as the Rocky Mountains.

The model Nicholson and colleagues created suggests the actual gap in the ring is about a half a kilometer wide, but part of the ring rises 3 km (2 miles) in the air up. The different angles the two spacecraft observed from made the gap look wider to Voyager than to Cassini.

“The whole pattern rotates around at the same rate as the satellite Titan orbits Saturn, once every 16 days,” said Nicholson said. Sometimes, the tsunami-like wave couldn’t be seen by the spacecraft, which accounts for how the gap seems to appear and disappear.

Nicholson said this model explains the C ring gap, “better than you have any right to expect,” but there could be three or four dynamical processes going on that explains the other gaps.

Nicholson and Cassini Deputy Project Scientist Linda Spilker said the same types of processes seen in Saturn’s rings could also explain what is seen in disks of debris around other stars, with the theory that there are gaps forming in the disks associated with the formation of planets.

...

New insights into the nature of Saturn’s rings are revealed in this panoramic mosaic of 15 images taken during the planet’s August 2009 equinox. Image credit: NASA/JPL/SSI

...

“Saturn provides a wonderful natural laboratory of how protoplanetary nebula may evolve,” said Spilker.

...

 

[CalliArcale]

Coooooooollllll......

There is a reason why I think the Cassini mission is the most spectacular to date. Stuff like this is why. It's paying for itself many times over with these detailed, long-term observations of an extremely complex system. The things scientists are learning from Saturn (thanks to Cassini) will inform not only understanding of planetary formation and the search for Earthlike worlds but also the behavior of our own solar system. That could one day become a matter of life or death, when we find the asteroid with our name on it. And if nothing else . . . my God, but it is beautiful!

 

[EarthlingX]

Very well put CalliArcale, very much how i feel about it

http://www.universetoday.com : Saturn’s Rings Formed from Large Moon’s Destruction

Oct 5th, 2010

by Nancy Atkinson

The formation of Saturn‘s rings has been one of the classical if not eternal questions in astronomy. But one researcher has provided a provocative new theory to answer that question. Robin Canup from the Southwest Research Institute has uncovered evidence that the rings came from a large, Titan-sized moon that was destroyed as it spiraled into a young Saturn.

...

Canup’s new alternative theory is that Titan-sized moon with a rocky core and an icy mantle spiraled into Saturn early in solar system history. Tidal forces ripped off part of the icy mantle, distributing it into what would become the rings. But the rocky core was made of more durable material that held together until it hit Saturn’s surface. “The end result is a pure ice ring,” Canup said in an article in Nature.

Over time the ring spreads out and its mass decreases, and icy moons are created. Due to changes in the evolving Saturn system, these “spawned” moons then spiraled outward rather than inward. In this way, ice rings and ice-enhanced inner moons originate as a primordial byproduct of the same process that produces Saturn’s regular satellite system, making the whole process simpler than if there were several events.

Canup studies formation events with detailed computer simulations, including studying how our own Moon formed.

She presented her findings at the American Astronomical Society’s Division for Planetary Science meeting this week, in Pasadena, California, and her presentation was detailed in an article in Nature.

Sources: Canup’s abstract, Nature

Forum sw can't digest link to the Canup's abstract, check in the article.

 

[EarthlingX]

Janus Flyby :

[youtube]http://www.youtube.com/watch?v=9ntaYfWBz4o[/youtube]

planetaryprobes | October 06, 2010

 

[EarthlingX]

Titan on: Monday 27th September 2010. Largest clouds seen to date over the equator of the giant 5,150 KM wide moon of Saturn.

I have rotated the below image so north is top. The clouds are seen over the western limb.


Andrew Brown.

Supplemental art :

www.ciclops.org : Seasons of Titan

"The idea for this image came from the Cassini images of Titan showing clouds forming near the moon's equator on 27 September 2010. Carolyn Porco and Anthony Del Genio from the Cassini Imaging Team provided invaluable details to complete this piece. The information they provided such as the orientation of the spacecraft, make-up of the atmosphere, colors and textures gave me the details that I just couldn't have gleamed from the initial raw images."


Greg Prichard © 2010
Artist's Website

 

[3488]

Cassini Spacecraft observes gigantic thunderstorms & resulting chemical changes in Saturn's clouds due to lightning.

Cassini Spacecraft observes gigantic thunderstorms.

Saturn gigantic thunderstorms.

Andrew Brown.

 

[EarthlingX]

saturn.jpl.nasa.gov : Cassini Catches Saturn Moons in Paintball Fight

Oct. 07, 2010


These three views of Saturn’s moon Rhea were made from data obtained by NASA’s Cassini spacecraft, enhanced to show colorful splotches and bands on the icy moon’s surface. Scientists believe the reddish and bluish tints came from bombardments large and small.

PASADENA, Calif. – Scientists using data from NASA’s Cassini spacecraft have learned that distinctive, colorful bands and splotches embellish the surfaces of Saturn’s inner, mid-size moons. The reddish and bluish hues on the icy surfaces of Mimas, Enceladus, Tethys, Dione and Rhea appear to be the aftermath of bombardments large and small.

A paper based on the findings was recently published online in the journal Icarus. In it, scientists describe prominent global patterns that trace the trade routes for material exchange between the moons themselves, an outer ring of Saturn known as the E ring and the planet’s magnetic environment. The finding may explain the mysterious Pac-Man thermal pattern on Mimas, found earlier this year by Cassini scientists, said lead author Paul Schenk, who was funded by a Cassini data analysis program grant and is based at the Lunar and Planetary Institute in Houston.

“The beauty of it all is how the satellites behave as a family, recording similar processes and events on their surfaces, each in its own unique way,” Schenk said. “I don’t think anyone expected that electrons would leave such obvious fingerprints on planetary surfaces, but we see it on several moons, including Mimas, which was once thought to be rather bland.”

This schematic graphic illustrates the bombardments that lead to colorful splotches and bands on the surfaces of several icy moons of Saturn.

These three enhanced-color views of an equatorial region on Saturn’s moon Rhea were made from data obtained by NASA’s Cassini spacecraft. The colors have been enhanced to show colorful splotches and bands on the icy moon’s surface.

Schenk and colleagues processed raw images obtained by Cassini's imaging cameras from 2004 to 2009 to produce new, high-resolution global color maps of these five moons. The new maps used camera frames shot through visible-light, ultraviolet and infrared filters which were processed to enhance our views of these moons beyond what could be seen by the human eye.

The new images are available at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

“The richness of the Cassini data set – visible images, infrared images, ultraviolet images, measurements of the radiation belts – is such that we can finally ‘paint a picture’ as to how the satellites themselves are ‘painted,’” said William B. McKinnon, one of six co-authors on the paper. McKinnon is based at Washington University in St. Louis and was also funded by the Cassini data analysis program.

Icy material sprayed by Enceladus, which makes up the misty E ring, appears to leave a brighter, blue signature. The pattern of bluish material on Enceladus, for example, indicates that the moon is covered by the fallback of its own “breath.”

This set of enhanced-color maps made from data obtained by NASA's Cassini spacecraft show Saturn's moons Mimas, Enceladus, Tethys, Dione and Rhea.

Enceladean spray also appears to splatter the parts of Tethys, Dione and Rhea that run into the spray head-on in their orbits around Saturn. But scientists are still puzzling over why the Enceladean frost on the leading hemisphere of these moons bears a coral-colored, rather than bluish, tint.

On Tethys, Dione and Rhea, darker, rust-colored, reddish hues paint the entire trailing hemisphere, or the side that faces backward in the orbit around Saturn. The reddish hues are thought to be caused by tiny particle strikes from circulating plasma, a gas-like state of matter so hot that atoms split into an ion and an electron, in Saturn’s magnetic environment. Tiny, iron-rich “nanoparticles” may also be involved, based on earlier analyses by the Cassini visual and infrared mapping spectrometer team.

Mimas is also touched by the tint of Enceladean spray, but it appears on the trailing side of Mimas. This probably occurs because it orbits inside the path of Enceladus, or closer to Saturn, than Tethys, Dione and Rhea.

In addition, Mimas and Tethys sport a dark, bluish band. The bands match patterns one might expect if the surface were being irradiated by high-energy electrons that drift in a direction opposite to the flow of plasma in the magnetic bubble around Saturn. Scientists are still figuring out exactly what is happening, but the electrons appear to be zapping the Mimas surface in a way that matches the Pac-Man thermal pattern detected by Cassini’s composite infrared spectrometer, Schenk said.

Schenk and colleagues also found a unique chain of bluish splotches along the equator of Rhea that re-open the question of whether Rhea ever had a ring around it. The splotches do not seem related to Enceladus, but rather appear where fresh, bluish ice has been exposed on older crater rims. Though Cassini imaging scientists recently reported that they did not see evidence in Cassini images of a ring around Rhea, the authors of this paper suggest the crash of orbiting material, perhaps a ring, to the surface of Rhea in the not-too-distant past could explain the bluish splotches.

Mimas’ Blue Streak
This enhanced-color view of Saturn’s moon Mimas was made from images obtained by NASA’s Cassini spacecraft. It highlights the bluish band around the icy moon’s equator.

“Analyzing the image color ratios is a great way to really enhance the otherwise subtle color variations and make apparent some of the processes at play in the Saturn system,” said Amanda Hendrix, Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “The Cassini images highlight the importance and potential effects of so-called ‘space weathering’ that occurs throughout the solar system – on any surface that isn’t protected by a thick atmosphere or magnetic field.” The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, 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.

 

[3488]

Thank you very much EarthlingX.

I was just about to post those up myself, they are also on Planetary Photojournal.

On: Saturday 16th October 2010, Cassini will pass only 69,947 KM from Mimas, will be in a fat crescent phase & also the cntral peak of Hearshel Crater will be seen in profile, juting above the crater rim.

Also an extrememly good non tarhetted pass of Dione on: Sunday 17th October 2010, passing Dione at 31,708 KM, close enough to obtain some high resolution frames of the poorly known Janiculum Dorsa, a large 'ridge' as well as some further sharp views of Dione's north pole.

More fun stuff for me to play with.



Andrew Brown.

 

[EarthlingX]

You are very much welcome

I find forum format much easier for learning than jumping all over the place after bits and pieces. Post above has images from sub-articles, because they are bigger, and post on JPL has a slideshow, which is nice, but can't see them all at the time, plus i can't link it here - no thumbs.

Oh, and there are real colour maps - i don't think i saw that before ? :shock:

I look forward to your images, they are always a treat :geek:

 

[EarthlingX]

www.universetoday.com : Titan’s Atmosphere Could Produce Building Blocks of Life

Oct 7th, 2010

by Nancy Atkinson

Saturn’s moon Titan has long been thought to be an analog of early Earth, and a recent experiment demonstrates that amino acids and nucleotide bases — which are the basic building blocks of life on Earth – could very easily be under production in Titan’s hazy atmosphere. “Our intention was to figure out what goes on in Titan’s atmosphere using high resolution mass spectrometry,” said Sarah Horst, from the University of Arizona, a member of an international team conducting the research. “We found there could be a high number of some incredibly complex molecules being created.”

...

Source: DPS briefing

 

[MeteorWayne]

Source: DPS briefing

For those who don't have a secret decoder ring, DPS is:
American Astronomical Society’s Division of Planetary Sciences

 

[EarthlingX]

Source: DPS briefing

For those who don't have a secret decoder ring, DPS is:
American Astronomical Society’s Division of Planetary Sciences

Yea, sorry folks, and thanks MW for pointing that out.

More DPS meeting stories can be found on Twitter, tagged with #DPS2010.

 

[EarthlingX]

http://www.planetary.org : DPS 2010: Friday morning at Titan's surface

Oct. 8, 2010 | 16:40 PDT | 23:40 UTC

By Emily Lakdawalla

I debated whether to attend the Titan surface or near-Earth asteroids sessions on Friday morning and decided, in the end, to go to Titan, because I feel like I have just not been writing enough about Saturn's planet-like moon lately. I'm glad I did, because I got a good picture of the current status of Titan science. There's quite a lot of debate going on.

...


http://www.planetary.org : I'm part of the conspiracy, apparently

Oct. 8, 2010 | 14:47 PDT | 21:47 UTC

By Emily Lakdawalla

Oh, bother. From the Bad Astronomer I learned that a Cassini pic of Titan and Dione that I processed is apparently evidence of a NASA coverup, at least according to some guy on Youtube. And then I found out that there are newspapers that use random guys on Youtube as a source for news stories. (Here it is in Australia, and in Belgium. And holy cow, it's now on the Fox News website.) This is a weird world.

...


http://www.ciclops.org : Rev139: Oct 4 - Oct 28 '10

Cassini continues its new tour of the Saturn system with the 24-day-long Rev139, the spacecraft's 140th orbit around the Ringed Planet, the fifth full orbit of the new tour and the first orbit under the new program, the Cassini Solstice Mission. Cassini begins Rev139 on October 4 at its farthest distance from Saturn, called apoapse. At this point, Cassini is 2.88 million kilometers (1.79 million miles) from Saturn's cloud tops. Cassini is in a slightly inclined orbit, 4.7 degrees out of the ring plane. This is still close enough to provide Cassini an opportunity to examine some of Saturn's moons. Cassini will perform several interesting non-targeted flybys (encounters with satellites at distances of less than 100,000 kilometers, or 62,000 miles, that do not require engine burns to reach) of some of Saturn's icy satellites.

...

 

[EarthlingX]

http://www.planetary.org : Six moons with one shot

Oct. 9, 2010 | 15:46 PDT | 22:46 UTC

By Emily Lakdawalla

There are six, count them, six moons in this photo. Plus the outer edge of Saturn's rings. Awesome.

On October 6, 2010, Cassini managed to catch six different moons passing through its narrow-angle camera field of view at once. At the time, Cassini was on the southern (shadowed) side of the rings, so the uppermost part of the rings are closest to Cassini, and rings and moons orbiting Saturn appear to be going in a clockwise direction. With the Sun behind and to the left of the rings as seen from Cassini, the skinny multiple braid of the F ring is the brightest of all the visible rings; its sparse, dusty material scatters light forward to Cassini like dust motes in a sunbeam. The largest moon visible, Enceladus, is the farthest away from Cassini. Both Enceladus and Janus, the oval-shaped moon above it, have night sides lit by light reflected from Saturn. To the right of both Enceladus and Janus, between the bright F ring and the main rings, is Atlas. Immediately above Janus, orbiting along with a pair of ringlets within the Encke gap, is Pan. (Pan appears to be accompanied by a clump in one ringlet.) Immediately above Pan is Daphnis, making a bright spot within the Keeler gap at the outermost edge of the main rings. Above the F ring near the upper right corner of the image is Epimetheus. Unlike Janus and Enceladus, Epimetheus is located between Cassini and Saturn, so its night side is not lit up by reflected Saturnshine. Credit: NASA / JPL / SSI

This kind of coincidence of moons passing through Cassini's extremely narrow Narrow-Angle Camera field of view is a really, really unlikely event. But if you spend long enough at Saturn, it can happen. Cassini doesn't catch six moons at once by accident, though; someone on the imaging or planning teams had to figure out that this coincidence was going to happen, and that it would happen at a time that Cassini could take a photo, and then get the photograph into Cassini's long list of instructions; so well done and thanks to whoever it was on the Cassini team who was responsible for grabbing this incredible shot!

...

Six moons with one shot (animation)
Credit: NASA / JPL / SSI / animation by Emily Lakdawalla

...

 

[3488]

Fantastic image obtained on Christmas Day 2009. Night side of Saturn with Saturn lit Enceladus with the plumes in the background. Left wide angle view. Right narrow angle view of Saturn lit Enceladus.



Andrew Brown.

 

[EarthlingX]

Another story from American Astronomical Society’s Division of Planetary Sciences briefing :

planetary.org : "A very sad story": No rings for Rhea after all

Oct. 12, 2010 | 14:30 PDT | 21:30 UTC

By Emily Lakdawalla

A couple of years ago, a story published in Science made a big splash: Rhea, Saturn's second-largest moon, appeared to have rings. The evidence was from the MIMI instrument on Cassini. During a flyby on November 26, 2005, MIMI detected something blocking the flow of electrons in Rhea's neighborhood, something that made three pairs of dips on each side of the moon.

...

Possible rings at Rhea?
As Cassini flies by the icy moons, its Magnetospheric Imaging Instrument (MIMI) measures the flow of electrons through Saturn's magnetosphere. In a flyby of Tethys, the flow of electrons was constant until it was blocked by the bulk of the moon, then the flow resumed when Cassini came out of the moon's shadow. However, during the November 26, 2005 flyby of Rhea, MIMI witnessed a decline in the flux of electrons within Rhea's gravitational influence, as well as three pairs of steep drops in the electron flux that may indicate the presence of three rings (or ring arcs) in orbit around the moon. Credit: MIMI instrument, courtesy Geraint Jones

...

Equatorial UV-bright spots on Rhea
This image covers the entire equator of Rhea, Saturn's second largest moon. It is a map of Rhea's infrared reflectance divided by its ultraviolet reflectance; brighter areas are "redder" and darker areas are "bluer." There is a line of dark spots running across 75% of Rhea's equator, tiny spots that are relatively bright in ultraviolet wavelengths, an indicator of fresh impacts. Their coincidence with the equator is unusual, and may indicate the impact of a short-lived ring onto the surface of Rhea. Credit: NASA / JPL / SSI / Paul Schenk

...

Tiscareno explained that Cassini's cameras have now done extensive surveys in search of even the faintest of rings. I was under the impression that if the rings contained the right size of particles -- too large to be forward-scattering like the dust in Saturn's rings, too small and sparse to be individually resolved -- but according to Tiscareno, Cassini's cameras should, in fact, have been able to spot whatever was causing the MIMI signature if they were, in fact, a set of particles orbiting Rhea. He said Cassini's taken 64 images targeted with Rhea just off the edge of the frame, once at high phase (where small particles would scatter light forward to Cassini) and four times with very long exposures from lower phase angles. Despite the images being "pretty ratty," he was able to put upper limits on the brightness of rings and density of particles.

So he has a limit -- what if the rings are just sparser than the cameras can see? The first response from the MIMI team is that the particles were likely about a millimeter in diameter, which would be enough to make the signatures they saw yet not be detectable by the cameras. But, Tiscareno said, there's a problem. As the particles get larger, not only do they stop scattering light the way tiny particles do (making them harder to see when lit from behind), but they also don't block electron flow the way tiny particles do. The upper limit on the amount of mass in the ring imposed by the camera measurements is four orders of magnitude (that's ten thousand times) smaller than the amount of mass that would actually need to be in the form of millimeter-sized particles in the ring in order to produce the observed MIMI measurements.

So Rhea doesn't have rings. But that leaves the Cassini team with yet another puzzle. Something weird was happening in that MIMI signature. It actually wasn't observed on a subsequent flyby. "There is something really remarkable going on in physics" near Rhea, Tiscareno said. "Unfortunately it's not ring physics. Unfortunately for me anyway, because my funding is to do rings science."

 

[EarthlingX]

saturn.jpl.nasa.gov : 13 years since Cassini launch

The Cassini spacecraft and Huygens probe begin their seven-year journey to the ringed planet. The successful launch of Cassini aboard a Titan IVB/Centaur occured at 4:43 a.m. EDT, October 15, 1997.

CassiniSaturn :

13th Anniv launch cake enjoyed by all incl 6+ who've been on the mission since launch in '97.

 

[3488]

Oh my goodnes me, so it is. 13 YEARS, I remeber the day well. I was at a work placement in a Day Centre teaching Disabled People to use Microsoft Office & the radio was on. I requested BBC Radio 4 as I knew the launch was imminent & that the launch had been already been delayed 48 hours, due to high cross winds at the tropopause.

Word came through that the launch of Cassini was flawless, the Titan 4 had worked beautifully it was one of those moments of huge relief. It was a very steep ascent & Cassini entered space just to the east of Cuba, parking orbit took her over the Atlantic & Africa, the upperstage fired up & Cassini achieved escape velocity over Mozambique & out over the Indian Ocean towrds interplanetary space. Crossed the orbit of the Moon later that same day.

[youtube]http://www.youtube.com/watch?v=Ne7mN0Am38o[/youtube]

[youtube]http://www.youtube.com/watch?v=9PM-x7Qm7lg[/youtube]

Andrew Brown.

 

[3488]

On Saturday 16th October 2010, Cassini captured this view of a Crescent Mimas from 101,550 KM. This is a very rare view as most views of crescent Mimas with the Herschel Crater are from very much further away.

I have rotated the image so north is top, east is right & have contrast enhanced it. Cropped out a lot of black space on both sides.

Mimas, the innermost of the major moons of Saturn. Mimas is only 395 KM wide & is mostly composed of ice, with a little rock (85% ice to 15% rock). The average surface temperature is minus 186 Celsius.

Also on Sunday 17th October 2010, Cassini carried out double nontargeted passes of Rhea & Dione.

Rhea: Sunday 17th October 2010. Clickable thumbnails to full sized images. I have rotated the images so north is top, east is right & have contrast enhanced them.





Dione: Sunday 17th October 2010. Clickable thumbnails to full sized images. I have rotated the images so north is top, east is right & have contrast enhanced them.



Below: A sharpened, enlarged crop of Janiculum Dorsa on Dione. This is the highest resolution view yet of Janiculum Dorsa. Original frame is above.

What is apparent, at this much higher resolution, it is ancient, heavily degraded by impacts.


NASA /JPL.

Andrew Brown.

 

[silylene]

fascinating!

 

[EarthlingX]

saturn.jpl.nasa.gov : The (Long) Weekend Warrior: Nine Moons, 62 Hours

Oct. 19, 2010


Two images taken by Cassini over the weekend: Dione, left, and Rhea. While parts of Dione are heavily cratered like Rhea, there are other areas covered by relatively smooth plains. Those areas have many small craters, but few large impact scars, which indicates that they are geologically younger than the heavily cratered areas.

Taking a long-weekend road trip, NASA's Cassini spacecraft successfully glided near nine Saturnian moons, sending back a stream of raw images as mementos of its adrenaline-fueled expedition. The spacecraft sent back particularly intriguing images of the moons Dione and Rhea.

The Dione and Rhea pictures are the highest-resolution views yet of parts of their surfaces. The views of the southern part of Dione's leading hemisphere (the part of the moon that faces forward in its orbit around Saturn) and the equatorial region of Rhea's leading hemisphere are more detailed than the last time we saw these terrains with NASA's Voyager spacecraft in the early 1980s.

Of the five big icy moons of Saturn, Dione and Rhea are often considered a pair because they orbit close to each other, are darker than the others, and exhibit similar patterns of light reflecting off them. These new images, however, highlight the differences between these sister moons.

Both images show similar geographic regions on each satellite. However, scientists can identify differences in geological histories of the two bodies from differences in the numbers and sizes of visible craters on their surfaces. The number and size of craters on a body's surface help indicate the age of that surface – the more craters there are and the larger they are, the older the surface is.

...


saturn.jpl.nasa.gov : Titan -- Oct. 14, 2010 (raw)

October 19, 2010

NASA's Cassini spacecraft took this raw image of Saturn's moon Titan on Oct. 14, 2010, kicking off an action-packed long weekend that took the spacecraft by eight other moons. The camera was pointing toward Titan at approximately 207,643 kilometers (129,023 miles) away. This image has not been validated or calibrated.

...

 

[EarthlingX]

http://www.planetary.org : A Rhea flyby and a cloudy Titan with Tethys in color

Oct. 20, 2010 | 12:02 PDT | 19:02 UTC

By Emily Lakdawalla

Over the last few days, the Cassini Saturn orbiter's raw images website has been bursting with awesome pictures. In the past week, Cassini passed reasonably close to, and imaged, Titan, Mimas, Pallene, Dione, and Rhea. (Pallene is a tiny moon located between the orbits of Mimas and Enceladus). Here, just for fun, is an animation of five wide-angle photos of Rhea.

Cassini flies past Rhea
Cassini captured these five images of Rhea during a relatively close encounter (within 40,000 kilometers at closest approach) on October 17, 2010. The images were captured with its wide-angle camera, which has a field of view ten times broader than its companion narrow-angle camera. The biggest visible impact basin is Tirawa. Credit: NASA / JPL / SSI / animation by Emily Lakdawalla

...

There's an even cooler set of images that appeared on the website earlier today. They show that Cassini doesn't need to be close to the moons to take spectacular photos. We're seeing Tethys -- and its iconic Ithaca Chasma snaking across its surface -- poised in front of Titan, with the entire ring system foreshortened almost into nonexistence in the background.

Titan and Tethys
Cassini captured the images for this view of the icy moon Tethys poised in front of Titan on October 18, 2010. The faint line across the top is Saturn's entire ring system, viewed from the side. Credit: NASA / JPL / SSI / color composite by Gordan Ugarkovic

...

Cloudy Titan (enhanced)
An enhanced view of Titan's cloud bands on October 17, 2010. This image is the ratio of two images taken through methane window and blue filters, which cancels out some of the blurring effect of the atmosphere and reveals surface features (which appear dark) as well as a huge equatorial band of clouds (which appear bright). It also enhances the north polar hood and reveals some clouds in the mid-southern latitudes. Credit: NASA / JPL / SSI / composite by Gordan Ugarkovic

...

 

[3488]

On: Monday 18th October 2010, Cassini observed Dione & Titan being occulted by the night side of Saturn. I have rotated them so north is top, west is left & contrast enhanced them. Clickable thumbnails to full sized images.

First two show Dione being Occulted first.







Andrew Brown.

 

[3488]

Crescent Titan from 207,314 KM on Thursday 14th October 2010. Equatorial clouds are visible. Image has been rotated with north at top, west at left & cropped out.

Andrew Brown.

 

[EarthlingX]

saturn.jpl.nasa.gov : Cassini Sees Saturn Rings Oscillate Like Mini-Galaxy

Nov. 01, 2010

Vertical structures, among the tallest seen in Saturn's main rings, rise abruptly from the edge of Saturn's B ring to cast long shadows on the ring in this image taken by NASA's Cassini spacecraft two weeks before the planet's August 2009 equinox.

Scientists believe they finally understand why one of the most dynamic regions in Saturn's rings has such an irregular and varying shape, thanks to images captured by NASA's Cassini spacecraft. And the answer, published online today in the Astronomical Journal, is this: The rings are behaving like a miniature version of our own Milky Way galaxy.

This new insight, garnered from images of Saturn's most massive ring, the B ring, may answer another long-standing question: What causes the bewildering variety of structures seen throughout the very densest regions of Saturn's rings?

...

Now, analysis of thousands of Cassini images of the B ring taken over a four-year period has revealed the source of most of the complexity: at least three additional, independently rotating wave patterns, or oscillations, that distort the B ring's edge. These oscillations, with one, two or three lobes, are not created by any moons. They have instead spontaneously arisen, in part because the ring is dense enough, and the B ring edge is sharp enough, for waves to grow on their own and then reflect at the edge.

"These oscillations exist for the same reason that guitar strings have natural modes of oscillation, which can be excited when plucked or otherwise disturbed," said Joseph Spitale, lead author on today's article and an imaging team associate at the Space Science Institute. "The ring, too, has its own natural oscillation frequencies, and that's what we're observing."

...