If Titan has other weathering processes, like wind erosion (and I'm sure it does), then I'd expect the rainstorms to be more than just occasional to produce the intricate drainage seen in the pictures. Otherwise I'd expect the erosion to have effaced the smaller channels. I am frankly quite suspicious of any explanation that does not involve the regular flow of liquids along these channels. They should probably drag in some professional hydrologists -- I don't imagine that the scientists strongly expected that that competence would be required eight hundred million miles away.

If we had a more complete map of Titan, we could tell whether we only had these small drainage basins, or if they here and there unite into larger river-systems. Also, do they flow only into the dark areas, or are there other places where we have drainage?

The SOUND of Titan!
http://esamultimedia.esa.int/images/huygen...nds_descent.mp3

How cool is that!?

Lots of pics here.. http://danajohnson.quriophotos.com/peerSer...lode.jsp?id=772

Did Huygen ride the parachute all the way to the surface or did it cut it lose and freefall the last part to keep the parachute from draging or covering it.

Little to no benefit because the camera doesnt move. To do super res imaging on mars - they bump the camera around a tiny bit

Oh - and it parachuted all the way to the surface

Doug

Huygens landing mosaic

I was hoping atmospheric distortion might create a similar effect. We are lucky the parachute didn't cover the camera's field of view!

Alright, I've heard the audio files from the ride down and the meager sounds of wind while on the surface. Where's the file we're all interested in the most - the sound of the probe hitting the surface?

Im still wondering if all the severe compression artefacts are present because theye been saved for posting online or the images were transmitted in that way? Can anyone elaborate?

In the BBC program one of the scientists showed that 360 degree mosaic on a printed piece of paper and it had the same JPEG 'blocks' as the online version. So I think it's just a result of low contrast on Titan.

Judging from the mosaic, the river systems we've seen are all on a peninsula -- which could explain why we're seeing such small drainage basins. It would be wonderful to see images of the middle of one of the "continents". Oh well -- I suppose we're going to have to make do with muddy Cassini images for another decade -- or more.

It is much better than nothing.

Don't rule out cassinni images yet.


The more images we get of titan the clearer they will be.

And don't forget the radar.

So the light areas are icy uplands riddled with dendritic drainage channels. What process is creating the uplands?

Other things:

Not a single impact crater.

Where are the aeolian features? It looks fluvial to me.

Once we have built up a good amount of Radar, Vims, and ISS data, I think our picture will improve. BTW, here is my attempt at a super resolution view of the surface view. It is a combination of an image I made from 131 frames and an image I generated from selecting ten good frames from throughout the surface mission.

Here is a colorized version.

I have a problem with one of the green lines (A). I added some yellow ones to make clear why this is so. What do you think?

Tom

While amazed and delighted we got there at all, I am somewhat disappointed because from the actual imaging instrument's site, I was led to expect this sort of image ( warning it 2500x2500 ) :

http://www.lpl.arizona.edu/~kholso/images/...00_big_gnom.jpg

Did something go wrong ( channel A ? ) or was this sort of resolution never really expected ? ( In which case, why the picture on the arizona site ? ).

Stonehat

I think both the green a line and your yellow line are not correct. I will post my version when I get in to work. I am going to try to put together some panoramas before a public event here tonight.

I think I read somewhere that they need at least a week to put something like that togather.

Tom

The features don't line up right because the colorized mosiac at the bottom is put together wrong. I see one obvious feature that is duplicated. The right third of it probably does not fit on that side.

The first panoramic image released today was an "absolute raw" image according to the scientist that produced it at the press conference.. As others have said, I suspect when they've had enough time to properly process the images a much better version will be released.

Considering the confusing details, they probably need to use spacecraft attitude data to make sure they aren't lined up wrong.

But will the images be bigger?

The images are full size. Remember, these are framelets that are to be assembled into images. The problem is that we are missing half of them, so I hope they can put them together.

Assuming an ocean on Titan -- either now or in the past -- would it be subject to tides? What would the intervals between those tides be? Would they be larger or smaller than those on Earth?

I'm wondering whether these "shoreline" areas experience periodic inundations and desiccations, and if so, what the intervals between those inundations might be -- and whether this could be something that Cassini could detect.

The bottom camera shows an object in triplets 897 and 901 that is absent in all other surface triplets. It's in the bottom left corner. Other evidence for 'dust in the wind' or 'particles in a stream'?

Now you see it: http://homepage.mac.com/lyford/j/raw/triplet.901.jpg
Now you don't: http://homepage.mac.com/lyford/j/raw/triplet.903.jpg

Also, some of the bottom camera pictures show the lamp shining brighter than in others. Battery fluctuations?

As I posted on other sites since months, tides must be there with a fundamental period of the order of revolution /2 = 8 days.
The tidal amplitude in a hypothetical free global ocean would be of the order of about 15 meters !
In smaller basins it will be substantially lower, but I guess 1-3 m will be possible in basins of some 100 km diameter.

There is another very important action in smaller basins seldom mentioned: the "seiches". These are bathtub waves. On Lake Geneva, with a lenght of about 60 km, the seiches are of the order of 1m in amplitude and some hours full period. Seiches are exited not by tidal interaction, but by the wind.
On lake Constance, the mean amplitude is only about 25 cm, but in rare circumstances, there have been aperiodic seiches in the bay of Constance with an amplitude of 1,5 m and a period in the range of an hout
A strong steady wind is important. You have it on Titan - the wind speed must not be high since the surfave atmospheric density is about 10 times the earth atmosphere density so I guess some m/sex will be sufficient.
I think there are some calculations by exoerts about this matter for Titan - however I never read about in newsgroups etc.

Some people said there are no tides since Titans rotation period is equal its revolution period. Thats would be true for e=0, but there is a very substantial eccentricity of its orbit of 0.03 which will result in strong tides.(I published about it in 1982 in the german "Sterne und Weltraum")

There is a very interesting collection of images at this site.

Images that particularly caught my attention included:

This polar-projection panorama, and this regular panorama, by Christian Waldvogel, similar to the one released by ESA, but of higher quality.

Another mosaic of the 'shoreline'. by Kevin Dawson and enhanced by Anthony Leikens.

Kevin Dawson also compiled this image, comparing reference points between two mosaics at different heights.

This site was brought to my attention by Neil Halelamien.

Bill

>As I posted on other sites since months, tides must be there...

And nature is full of systems that get started and develop a resonance, no, a cyclic behavior. Good discussion of the possiblity of Titanian tides.

I wonder, would it be possible to explore Titan with a series of lighter-than-air blimps? What is the pressure/density/temperature of the atmosphere below the cloud deck, say at 5-15 km?

I imagine that a SAR/SLAR radar system similar to what was used with Venus would be wonderful to do the prelim recon of Titan.

Wonderful images, data and discussion!

--Bill

Well, we already have that on Cassini. Now, if in an extended mission it can get into orbit and provide global coverage with it, we might get some great imagery!

Wouldn't it require a hell lot of braking speed=fuel for Cassini to get into Titan orbit?

Maybe an extreme aero capture combined with a big main engine burn could do it

A few years ago, I read a Cassini Mission report on several options for a Cassini Extended Mission. One of the options was in fact aerobraking into a Titan polar orbit. I don't know which, if any, option was eventually chosen. The summary of the Titan Orbit Extended Mission option was that it held the potential for greatest scientific return, but was also the riskiest to perform.

Bill

Here is a list of options for Cassini in extended mission

http://digilander.libero.it/lucktam/EXT.html

Even escape gravity of Saturn is apparently an option

So let's go for Uranus and Neptune

Good plan!

Now, if we just can get Huygens back, we can investigate Triton as well

Hopefully it will be possible for the science teams to add some colour to the panoramic images taken during decent.... just as they have with the image taken on the surface.

No problem. We slingshot Cassini back to Earth. Installs a new Huygens probe build to land on Triton. Then we fuel Cassini and off we go again

Sounds like a great plan

Or maybe to far fetched after all...

No plan has yet been devised for any ultimate mission for Cassini, nor have even any plans for its first extended mission been accepted -- it all depends, after all, on what interesting things it finds at its various targets, and it's very easy to visualize the scientists wanting to take a better look than originally planned at, say, the rings or Enceladus.

However, Robert Mitchell did tell me a few years ago that, as things now stand, better surface coverage of Titan is regarded as the single most important goal in any extended mission.

Except that with Triton's thin atmosphere, the descent would last a minute or two max, followed by a high speed impact that would probably leave a crater and all traces of the Huygens. Retrorockets would be needed on Triton.

The revelation last night that the heated inlet of the GCMS after landing evaporated some liquid methane from the "soil" of Titan in the dark drainage area where it landed suggests to me that Titan's surface may be an eerie analog of Earth's deserts, with water ice serving as the sand and rock, and the drainage channels being its arroyos -- channels carved by occasional light rains of liquid methane coming down from Titan's small clumps of clouds, with the liquid then evaporating or soaking into the porous water-ice regolith (pulverized by the rain of meteor impacts over the eons) to form drying "mud".

This may actually be a lot more likely than my earlier theory that the channels might have been carved even more slowly by the geologically slow drizzle of liquid ethane from the skies. Quite apart from that liquid methane in the soil, the ethane downflux is so slow that it's hard to visualize it totally erasing even the most recent small impact craters on Titan's surface ( which are indeed totally missing in all the pictures we have); and since it's so slow, I would also tend to think that it would all soak vertically down into the soil instead of running horizontally across the surface -- although I suppose it might encounter a solid underlying stratum a short distance down across which it would then flow sideways underground, thus carving out the channels by underground sapping rather than surface flow. (That latter theory, however, could also fit the idea that the arroyos were carved by liquid methane rain.) The black goo would be the residue of solid organics very dilutely mixed with the rain and accumulated on the floors of the arroyos and drainage playas over the eons, having been washed off the higher ground.

By the way, we have here an indication that the heated GCMS outlet -- by itself -- has told us a lot more about Titan than all of Zarnecki's SSP sensors combined. Indeed, except for the acelerometers -- and maybe the thermal conductivity and speed-of-sound sensors -- I imagine all of them were utterly useless in that solid (or thick semi-solid) material; even the graph of the echo sounder's data shown last night showed a clear echo from the surface during the last 100 meters of descent, but no sign of any subsurface structure visible in each echo. (But then, I'm surprised that all the SSP sensors and the heated GCMS inlet even functioned after landing -- those two experiment packages protrude some distance below the lander's main deck, and Ralph Lorenz had predicted they'd both be wrecked if the lander came down on any significantly hard surface. Incidentally, the ESA wasn't the only group hesitant to put the SSP on Huygens -- in its 1992 instrument recommendations for the Cassini mission, COMPLEX suggested that impact accelerometers should be the only specifically surface-related sensors on it.)

I've put out an E-mail to Tomasko, Lorenz, Peter Smith and Katie Holso asking them whether Huygens did get any images between 8 km altitude and the surface, or between 16 and 8 km. No replies yet.

An examination of the description of the DISR ( http://www.rssd.esa.int/SB/HUYGENS/docs/SP1177/tomask_1.pdf ) would suggest that they could have alternated very easily between Channels A and B for the images below 8 km. After a final 36-image panorama at 5 km, Huygens was supposed to NOT completely fill its DISR buffer again before downloading its accumulated images to the probe's radio system, in order to avoid the possibility that it might crash and fail before the final images could be sent back. Insted, it was supposed to take -- and then immediately send back -- isolated image triplets between 3 km and 500 meters, and then 2 to 5 isolated individual frames from the down-looking HRI between 2 km and 500 meters -- and it could easily have alternated the transmission of these individual triplets or singles between the two channels, since by then it was taking 2 minutes or more to fall one kilometer. Whether they actually followed this seemingly common-sense course of action, or devoted all the final pre-impact images to Channel A for some reason I don't yet understand, is the question. (I do know, thanks to last night's press conference, that they duplicated all the DISR spectral measurements -- which had a smaller data volume -- on both Channels, right to the end.)

Why do we need to invoke rainfall at all, except as a source to replenish the methane with which, it sounds like, the ground is soaked? [Not exactly parallel to a desert.] Most rivers on earth are fed either by the melting of a permanent snow and ice cover, or by springs from which excess groundwater emerges. Why couldn't the channels we see be fed by an underground "methanifer"?

Well, Huygens touched down in one of the dark areas -- presumably one of the places onto which the channels drain (the "playas", as I'm starting to think of them). And to assume that the channels are initially supplied from an underground methane aquifer, one would, I think, have to assume that this aquifer, located on higher ground, is somehow itself at higher altitude than the drainage basins without filling them directly.

There has been some difficulty explaining the valley networks on Mars as due to underground sapping for this reason -- in that case, the assumption is that either local geothermal heat melted some underground ice in some of Mars' higher-altitude regions, or that local precipitation (maybe snow which later melted) dumped liquid water onto some areas in Mars' high-altitude terrain and some of it trickled directly down through the ground to supply a high-altitude aquifer there. But these theories can't apply on Titan -- there seem to be drainage channels leading away from virtually EVERY patch of higher ground there.

News which pleases me no end: Bashar Rizk, the head of the DISR imaging team, has just gotten back to me via E-mail with the following message:

Moomaw: "Given the loss of half the DISR images due to the foul-up with Channel A, could you tell me whether Huygens returned any images from between 8 km altitude and the surface -- and also whether it returned any from the two panoramas planned for 14 and 11 km altitude? Thanks very much for your time and trouble -- and congratulations."

Rizk: "Yes, we got some 56 images between 8 km and the surface, by our estimates, but this could be off by 5 or 10 in either direction, because our altitude scale is still uncertain. We returned images from all altitudes, just half as many as expected due to the loss of Chain A. The images were lost from the transmission randomly, because our onboard software, not knowing about the lack of power on the RUSO on the orbiter, kept adding to chain A, as well as chain B. If the failure had occurred on the probe, we could have directed every image to chain B and had complete triplets at the cost of fewer panoramas, a trade we would gladly have made, but c'est la vie. We feel grateful and lucky to have even gotten data, considering that DWE got nothing."

Obvious next questions (which I've asked him):

(1) When will those lower-altitude images be released?

(2) If Huygens sent individual frames in each panorama to both channels, how did they get the complete 360-degree panorama at 8 km altitude which was released at last night's press conference?

Still, while he seems unhappy that they got discontinuous panoramas at a wider variety of altitudes rather than complete panoramas at a smaller number of altitudes, I'm absolutely delighted that they apparently did get some really low -altitude aerial views of Titan's landscape as well. I will, of course, let you know immediately when I hear more news on all this. (Also, note his flat statement that the failure came because the RUSO receiver on Cassini had not been turned on.)

Bruce I skimmed through the pdf you linked to. According to it the surface science lamp comes on at 400 meters and the last image is taken at 200 meters The light appears to be on in these images:
http://homepage.mac.com/lyford/j/raw/triplet.710.jpg
http://homepage.mac.com/lyford/j/raw/triplet.716.jpg
So it looks like they got at least two images back from below 400 meters. Not much to see in them, I guess the rocks were to small to be resolved at that altitude.

Hi all --

Been lurking here for several months, mostly on the MER boards, but have enjoyed the Titan discussion as well. Thanks.

On the topic of the "official" first image release (the "drainage channel" image at about ~11:50PST (~19:50UTC) on Friday), and the subsequent applause by the gathered officials: I could have sworn I saw the image on the screens of the Huygens mission control room before the official program began. Sure enough. On reviewing the tape, during the live feed of the control room ~3 minutes before official program begins, the image of the "drainage channel" comes up on a couple of the big screens (you even see a couple of people remark on it, though they don't look that excited about it). They then cut to the little ESA / Huygens intro, then there's the whole "event" with Martin Ransom, the "reveal" (without actually seeing the image), extended applause, and that commentary by various officials.

Perhaps I was completely foolish to think that was the first time those gathered individuals had seen the image, but I felt rather misled, particularly when contrasting it with the spontaneity of not only the MER image releases on those first nights, but even the commentary by Carolyn Porco of the Saturn ring images as they streamed down shortly after SOI. I have my problems with NASA TV coverage, but the kind of "staged" release that I saw from ESA really drives me insane, and makes me thank my lucky stars for NASA and JPL.

Anyway, back to the real stuff, which due to the wonders of the web we have in hand (the lack of "official releases" notwithstanding).

Thanks again for all your great insights and imaging work.

In this connection, a question for Lyford: you claim that your (very useful) collection of images at http://homepage.mac.com/lyford/j/raw/_._.html is a mirror of the raw files that were originally posted at http://www.lpl.arizona.edu/%7Ekholso/data.htm before the ESA demanded that they be yanked. But your site lists fully 367 triplets, whereas (judging from the number of links) there were only 16 triplets on that DISR page. What gives?

Bruce, they were all posted in this folder before they were yanked, the web server gave the whole list as a directory listing. The website had (and still has) links to only 16 of them.

In that case, there's still a puzzle -- those 367 triplets included, by definition, 1101 individual frames, and only about 122 of the triplets seem to have been taken after landing, leaving us with about 735 frames on Lyford's site that were apparently taken before landing. But only about 350 are supposed to have been returned before landing (and the original plan, according to http://huygens.oeaw.ac.at/Papers/DTWGRev3.pdf and http://www.rssd.esa.int/SB/HUYGENS/docs/SP1177/tomask_1.pdf , was indeed to return only about 600 before landing and another 250 during the first 10 minutes after landing). So one is virtually forced to the conclusion that there must be one hell of a lot of duplicates on Lyford's site, and thus in the original DISR raw images file. Also, are the 2 to 4 non-triplet individual HRI shots that were supposed to be taken below 500 meters in there somewhere, or were they lost on Channel A?

I'm not sure why that's a problem. Mountain springs are not exactly rare. If springs are feeding the channels in the pictures, they are obviously a lot closer to the elevation of the dark area. I know of a spring that bubbles up within a hundred feet of a lake and is probably only one or two feet higher in elevation.

As for the (apparent?) "dry" state of the landing site, first of all I'm not really clear on how "dry" it is; from the description, it sounds as if the ground is actually mud or liquidy sand. How do we know that the outflows aren't just soaking into the dark area and saturating the ground but only pooling at altitudes lower than where the lander is sitting?

The "shoreline" formations suggest to me that the area has been inundated, or gets inundated regularly, with the same stuff that leaves the dark deposits in the channels. Maybe this is just a relic of a past climate. Or perhaps in eight days a tide will come in and wash Huygens out to sea.

But if we're looking at a dry ex-lake bed, why don't we see channels cut through the dark zone as well? If you had periodic inundations and an unstable surface, of course any channelling through the dark zone wouldn't last. But if you have a dry dark surface and periodic if rare rainstorms cutting arroyos through the light zone, I see no reason that they shouldn't cut through the dark zone as well.

Nice montage of images at http://www.spaceflightnow.com/cassini/imag...0115montage.jpg -- including one which, it's absolutely clear from the context, was taken at considerably lower than 8 km altitude.