Mimas is stunning up close. Herschel's internal slump, with it's "bathtub" rings, is an amazing image of chaos. The shape of the chaos inside Herschel reminds me that this is a ball of ice...that was shock melted by impact, inside of Herschel.
re: billclawson - I think the lack or ray features is more a measure of the low gravity of Mimas, than anything else. Most ejecta from craters would likely leave Mimas forever...and thus, a very low rate of secondary craters. Probably not non-existent, but very few would make sense to me. And thus, Mimas has very randomly arrayed cratering pretty much at saturation. New craters can't occur without wiping away older craters and crater features.
Love the images of Mimas, especially the high res imagery of the inside of Herschel crater. Quite a chaotic landscape! I've checked through the raw imagery and there appears to be a borderline between the crater wall and the slump features...almost like a black outline...very curious. There appears to be a layer of dark material at the transition between the avalanche features and the steep crater wall. I've been waiting a long time to see details inside this amazing crater...you haven't disappointed, once again!
And then there's Calypso at what, 30 kilometers in the long axis? What an amazing image of that tiny bit o' real estate! The flow features on the surface bear a resemblance to glacial features on Earth, with a serpentine path evident. There appears to be a river of ice flowing from top right to center bottom in the image. And the near total absence of craters makes it clear that this is a very young surface that has likely been the result of the accumulation of ices on the surface, from the E-ring. I haven't been able to find a reference to Calypso's gravity, but it certainly is minuscule, and the flow features would move in interesting paths with so little friction and weight. Seems like ices could almost literally float in gravity so low. Wouldn't take a lot of energy to move the particles "downhill".
The image of Prometheus is stunning! The lighting looks especially strange...is this the result of ring shadow? I hope that Cassini lasts long enough to really focus on the small moons. Titan is an amazing moon, but each of the moons has a profound story to tell, and after dozens of Titan encounters, how bout shifting the focus onto the lesser moons? For instance, the crater Herschel on Mimas has yet to be imaged at high resolution. The high res sequence of Mimas was of the opposite hemisphere.
I know it's a matter of fuel and trajectory, and the orbits have pretty much designed to optimize viewing at Titan, but isn't it time to shift the focus to some of the other moons? With limited resources, and the inevitable end of the mission looming, I find it kind of frustrating seeing these amazing shots of the lesser moons, and realizing that these are secondary and tertiary objects relative to the mission's primary goal, which was to draw back the curtains on Titan. That's been achieved...more of the little moons, PLEASE!
And, don't get me wrong...this is one of THE greatest space missions in the history of spaceflight. Kudos for many jobs well done!
Great imagery. Titan is, of course, the jewel of the system, but every single moon has a unique story to tell. I am looking forward to the close flyby's coming up in 2010 of some "lesser" moons, like Mimas on Feb. 17 (not listed as a "close" flyby, but I mention it cause I hope that higher res imagery of Herschel will be possible) Rhea on March 2nd, Helene on March 3rd, Dione April 6th, Enceladus on April 27th & May 18th. The small moons have a lot to reveal at a much finer scale than the global attention at Titan. Don't get me wrong, the focus on Titan was clearly the proper thing to do, but personally I'm a little sad that more flybys of Iapetus weren't possible, but I understand that it is further out and more fuel intensive to get to. My point is, as in the Japanese success at Itokawa, it is clear that small celestial objects have unique data to provide to the ever expanding puzzle that is the solar system.
carolyn: A mission like this has to have images of sheer wonder, to go along with the mountain of science, with the goal of eliciting "wows". That's the icing on the science cake! Thanks for so many wows to go along with the serious science!
I didn't notice the plumes at first, then when I saw realized they were there, that was a wow moment.
Image #1 is truly an awesome shot. To have captured the limb of Saturn, and still have caught the plumes erupting from Enceladus' south pole in the same shot and exposure, is truly a masterwork! All the images are history in the making...marvelous work and congratulations to the imaging team for these magnificent shots! If only Cassini could just go on and on...such a huge success for planetary science, and especially the field of comparative planetology...Saturn is a master class in this field, with it's multitude of magnificent moons, not to mention the ever awe inspiring ring system.
It occurs to me that the block distribution might have a direct relationship to the low gravity, which according to Wikipedia is 0.0113g...one ton would tip the scales at about 22 pounds. The block distribution takes on a different character under such a low gravitational field.
Just a thought...
I fully understand the need to focus on Titan, and the results of all the flybys have been stupendous, but I must say, imaging of the small moons is very interesting to me. Also, the other large moons, Iapetus in particular, are of great interest to me. Iapetus is a mysterious object, and even with the two close flybys, remains so. The imaging of its equatorial mountain range was quite literally, stunning! I spotted multiple landslides of enormous scale on the flanks of the mountain range, but I've not seen any discussion of those amazing slump features.
There is one other really dramatic landslide in evidence on Iapetus, within one of the large craters. This large crater is approximately 375 miles across, and features a smaller, 75 mile diameter crater within it, that appears to have impacted such that it's rim is almost exactly tangent to the inner rim of the larger crater. This smaller crater is nearly half filled with an enormous landslide that propagated off the rim of the larger crater, which at this location is about 15km high! From the looks of the landslide, it appears to be perhaps 5km thick? When that landslide cut loose, it's impossible to imagine the forces involved...truly an awesome feature on Iapetus!
The best image I've seen of it is at the following address...
Great examples of massive slumping are evident on many of the moons, including the bright splat crater on Rhea, which has large lobular flows off of it's crater walls. That one in particular brought a question to my mind, which is, where did the energy come from to soften that material enough to cause the mass slippage? The crater floor is peppered with small craters, but the landslides are free of craters, which indicates that the slumping occurred long after the formation of the crater, and at least geologically speaking, perhaps not so long ago (a billion years?)...which makes the question of where the energy came from even more interesting. I thought, other nearby impacts, but the lobular form of the slides would seem to indicate liquefaction occurred...which would seem to indicate thermal energy transfer? The related image (wide angle) that I've looked at was taken on November, 26, 2005, is as follows...W00012124...an amazing image to be sure. So...anyone have theories on how those lobular flows were formed, in such a low energy environment?
One other moon that has been woefully missed, in terms of hi-resolution imagery, is Mimas. No hi-res imagery of the crater Herschel have been captured, only medium res. It's clear from the medium res imagery that this crater has been filled with mass slumping...but the lack of hi-res imagery makes it very frustrating. And while this post might indicate otherwise, I'm NOT obsessed with landslides!