Rene Pascal has done some amazing work with the Huygens images his latest
http://www.beugungsbild.de/huygens/ISS_huy..._correlate.html

Assuming that the mosaic of Huygens images is correctly assembled, I don't see how Pascal's asserted correlation with the ISS images can be correct. To my eye there seem to be glaring discrepancies in shape.

I wonder if radar will slove this problem.

I think it'll take ISS, Radar and VIMS to sort it out to be honest.

Titan is being a little more elusive than many hoped it would be

Doug

Here's part 3 of Lunine's transcript.

Comparing the Triad of Great Moons

Also, I am quite wary of his "calibration", suggesting that Huygens height estimates were off by as much as 250%, which I think is almost impossible. 10-20% I can see, maybe, but 250% is too far out there. there are also a few other issues to consider. First, the image he uses from ISS is in orthographic projection while the Huygens images have not been put into any projection, which is what would be needed in order to consider this issue. Second, ISS images of the landing site were taken at higher emission angles than we like and with lower SNR than we like so one has to use a grain of salt with some of the diffuse bright material surrounding bright terrain (is it real, is it an emission angle effect, this will require several more flybys to sort out).

Here's the last part.

On Ammonia and Astrobiology

With so many frames taken by Huygens of those icy blocks from the surface of titan is it possible to assemble a superresolution image showing more detail? I'm no whizz with photoshop, but stacking all the images to produce a superresolution image should be straightforward. I remember the same thing being done with pathfinder images to improve the resolution of the twin peaks.

I've tried - but the results are no good - to do proper Super Res - you need to have the camera actually moving a tiny ammount. With MER they did just that - move it around a little. With MPF - they moved it away, then back to supposedly the same position but slack in the mechanism made it slightly different. Huygens just sat there - so every pixel is looking at the identical patch of ground for the full series of images.

Doug

Thanks Doug, I guess quite a few people probably tried this and found the same result. I hadn't realised images had to be taken from fractionally different positions to create a super res image.

I would have thought that atmospheric effects, or settling of the spacecraft while on the surface could have performed a similar function to moving the camera. However, it would seem that there wasn't a suitable atmospheric shimmer or any spacecraft wobble.

Hmmm a big tilt between frames might even have throw up a nice stereo portion. Anyway the image from the surface exceeded my expectations, shame about the foglight effect of the lamp blocking the view from 20m though.

6 hr 20 min till next titan flyby

BBC is reporting the results of drop tests done in an attempt to simulate the penetrometer readings from Huygens when it splatted down on titan.

John Zarnecki from the article:

"A crust is still a possibility, but we now think it's most likely we hit one of those water-ice pebbles you see in the ground image; the biggest you see is about 15cm, We probably pushed the pebble to one side and then ploughed into the stuff underneath which we are pretty convinced is a 'sand' made of ice, A crust and a pebble will give you an initial peak but the match looks better with a pebble and if we're seeing lots of them in the ground image it's hardly fanciful that we've bashed one of them".

The results were presented at the Royal Astronomical Society National Astronomy Meeting 2005, held on the 4-8 April 2005. Here is a link to the conference reports.

Yes, what I and many others had suspected. Thanks for the link.

Another puzzle from the SSP results has just been explained, by Jason Perry (
http://volcanopele.blogspot.com/2005/04/hu...mri-images.html
#comments ):

"The Sonar instrument on the SSP experiment on Huygens detected a double
echo in the last 100 meters before landing. The shape and intensity of this
double peak, and its evolution from 100 meters altitude to the ground, is
consistent with Huygens having flown over a 5 meter tall cliff."

So THAT'S its explanation. Up to now I haven't seen it mentioned by anyone
besides myself, although it was very clear on the animated version of the
echo sounder's graph during the first Huygens scientific news conference.
This may be because the ESA didn't put that part of the graph on its webpage
of graphs from that news conference -- you had to be watching the animated
version, which ran very quickly, to see it, although if you did so, it was
(as I say) extremely clear.

The theory I had was that the sounder might be detecting a second echo off
the floor of a layer of mud below the capsule. I presume that the
post-landing data from the echo sounder now rules this out.

So we overflew a precipice in the last 100 meters of the decent. Given the parachute is not visible in the surface area can we assume that the image looks backwards along the last part of the ground track. (I imagine this information will be know once they have completely merged all the descent data).

I was looking at surface image again and i noticed that there is a horizontal white line just below the horizon. On the image attached it is visible level with the bottom of the left leg of the letter 'H' in the word horizon. This line to me looks more level that the bumpy horizon, could the white line be the cliff.

(EDIT: I just changed 'right leg' to 'left leg' in paragraph above after posting this message)

Could it be the bank of one of one of the sinuous features. i.e. have we landed in a dried channel (or part of the delta) looking at the shore. Could this scenario explain the distribution of boulders seen in the image. It reminds me of the kind of distribution you see in on the inside of a oxbow bend on a river. The ice blocks field appears to end and then there is a dark strip visible, could this be the dried main channel which on the far side ends in a 5 meter vertical bank (the white line/cliff) visible just below the horizon.

Well, we can't assume from the absence of a visible parachute that the camera was looking back along the groundtrack, because Huygens was suspended from its parachute by a swivel so that the vanes mounted on its bottom would make it twirl during descent to allow panoramas. (One of the strangest revelations at the recent LPSC meeting was that -- after the first 5 minutes of descent -- Huygens started twirling BACKWARDS, in the opposite direction from what the vanes should have generated. Photos of the Probe before it launched confirm that the vanes were installed on it the right way; I wonder if the swivel may have jammed after 5 minutes, so that all the probe's rotations later on were due to aerodynamic forces on the parachute itself.) Anyway, we don't know from the parachute's absence just what direction the SLI camera was facing after landing.

As for your possible distant bluff; I just don't know -- until that image has been better processed and interpreted by the team, it's possible that your near-horizon "white line" is just an optical effect like the lighter-colored triangle in the upper right corner of the image. However, if you look at the very last image returned by the SLI before landing ( http://esamultimedia.esa.int/docs/titanraw...riplet.721a.jpg ) -- at an altitude of 405 meters, Tomasko tells me -- you will see an intriguing-looking broad, Z-shaped light-colored strip running along the surface. While it's not clear what this is, I wonder whether it might be a flow channel itself.

New at the DISR site
http://www.lpl.arizona.edu/%7Ekholso/data.htm

"This animation displays (color-coded) the altimetry of the brighter highland terrain cut by dendritic channels near the Huygens landing site. The region pictured is approximately 1.5 by 3.5 km and displays a maximum relative relief of 150-200 m. The overall topography is still uncertain, but the relative topography is on a firmer footing."

(it's best to download this by right clicking and selecting 'save target as...' rather than viewing them online.)
“Animated Stereo Model of Topography near the Huygen Landing Site”
http://www.lpl.arizona.edu/~kholso/multime...s_arcmap_8A.avi

[quote=alan,Jun 18 2005, 05:36 PM]
New at the DISR site
http://www.lpl.arizona.edu/%7Ekholso/data.htm

"This animation displays (color-coded) the altimetry of the brighter highland terrain cut by dendritic channels near the Huygens landing site.
For those of us who cannot view AVI files could someone post some representative frames revealing the height data?

Don

The first frame is probably the most interesting one:

Has it been determined if that light patch at the bottom of the first frame is a surface feature or cloud or fog as originally speculated?

[quote=Bjorn Jonsson,Jun 19 2005, 01:26 AM]
The first frame is probably the most interesting one:

Thanks!

Unfortunately, I can't relate it to the images. Is this an oblique view tipped sideways? Is there an overhead view with a photo comparison? In their presentation of the local topography a contour map, and perhaps a grayscale DEM, would be the best presentation of any relief data. the trouble with combined shaded relief and spectrally colored height coded views is they are difficult to extract the data from in a quantitative way.

Don

The particular area they are highlighting in the animation is visible in a couple high res images, triplet 448 and triplet 461. Here's a frame around it, in context to the rest of the scene:

This is from directly above. Maybe I should convert the entire animation to an MPEG file.

[quote=Bjorn Jonsson,Jun 19 2005, 11:25 AM]
This is from directly above.

Ah, I see now thanks to the context photo, thanks again!
it looks like they are deciding to go out on a limb and assume the albedo variations in the surface can be treated as a DEM, with lighter portions assumed to be higher.

Don

For those that cannot view AVI files I have now converted the AVI file to an MPEG that can be downloaded at http://www.mmedia.is/bjj/misc/huygens_arcmap_8A.zip

Note: I will probably remove this file from my website in a few days when everyone interested should have seen it.

This looks for all the world like a sharp "shoreline", cutting across the bottom of the red rectangle, with "offshore" fog or clouds. Does anyone know what the latest thinking is on whether those are clouds or fog or surface features?

Everything you can see there is a surface feature. This area was viewed by Huygens from different altitudes, and the features have a consistent shape in all images.

Splendid new color views of Titan, as seen from different altitudes, from Rene Pascal:
http://www.beugungsbild.de/huygens/povray/...n_rendered.html

I don't know how accurate these are -- but Pascal doesn't simply pull this stuff out of a hat, and they at least appear entirely plausible.

Somebody at ESA should employ him to make official pans and other images, the ones he made look better than the officially released versions.

They are amazing!!!

Doug

Will there be any more stereo models of landing site topography?

I presume they got good stereo overlap elsewhere at the landing site...?

I doubt it - The stereo imaging required Huygens to photograph the same terrain from slightly different elevations, or angles. Huygens was suppose to be rotating while it fell, but for at small part of the descent it obviously crossed over the same terrain.

Even given the interminable delay in the "Nature" Huygens issue, we're starting to get a few intriguing crumbs on what chemicals Huygens found on Titan's surface. First, Sushil Atreya slipped up and accidentally made available for a short time on his website a free copy of an article he co-wrote with Toby Owen for the June issue of a Russian physics journal on Huygens' findings, which it turned out was supposed to be only available for purchase -- as I found out only after I'd run across and downloaded a copy of it. I hope I'm not violating either ethical or copyright laws when I mention that he did say that Huygens had found HCN, acetylene and a few other simple compounds, with the heaviest being benzene -- but that they had not yet found evidence of the heavier organic compounds that they had expected.

Second, on pg. 11 of Lunine's recent OPAG slide presentation on the proposed Titan Organics Explorer ( http://www.lpi.usra.edu/opag/oct_05_meeting/jpl_titan.pdf ) -- which is very interesting all-around -- there are two graphs presenting the GCMS results from 120-130 km up and on the surface. It's hard to judge from this graph whether Huygens did indeed see more HCN and C2H2 at the surface than the simple increase in air pressure could account for, but I'll take Owen's word for it. What the graph DOES clearly show is accumulated cyanogen and benzene on the surface, as the other scattered accounts have indicated -- and the latter is especially interesting because it's supposed to be a product of acetylene polymerization, which has always been thought likely to produce some quite heavy organics on Titan's surface by itself. And it looks to me as though -- contrary to that earlier article -- Huygens DID clearly pick up signs of accumulated heavier organics on the surface, some of them quite heavy.

But it doesn't seem to show any sign at all of CO2 accumulated on the surface. This might be due simply to CO2's higher sublimation temperature -- but in that case there must be one HELL of a lot of cyanogen and benzene on the surface, given their much higher evaporation temperatures. (Cyanogen boils at -4 deg C -- and benzene doesn't do so until +80 deg C!) I think the light-colored stuff on Titan's upper surface -- which continues to puzzle scientists because it doesn't match the near-IR spectra of water ice -- may consist largely of solid acetylene, acetylene polymers, and cyanogen.

On pg. 3 of the same Lunine presentation, by the way, we get a theoretical prediction of just how much of various compounds are predicted to have been deposited on the surface by the radiation synthesis in Titan's air. It predicts quite a bit of ethane, acetylene and HCN (which Huygens seems to have found) and of liquid propane (which unfortunately has the same AMU as CO2, so Huygens can't distinguish them). But it also predicted very little cyanogen, so that's a puzzle. (Ethylene unfortunately has the same AMU as nitrogen, so you can't measure it either.)

Slight correction: cyanogen's boiling point is -20 deg C -- which doesn't affect my points at all.

I would not expect a surface rich in benzene (and therefore benzene derivatives) to have such light and uniform coloration, something more of the tie-dyed variety.

Both frozen acetylene and its polymers are generally silverish in color -- which meshes nicely with what we're seeing. Moreover, benzene is a colorless liquid -- and http://www.dcchem.co.kr/english/product/p_petr/p_petr5.htm implies that it's white as a solid.

And, once again, for Huygens to pick up benzene vapor from the surface, given the very high boiling point of benzene (it doesn't even melt until +5.5 deg C), there must be one hell of a lot of benzene there.

By the way, ethane and propane are liquid at Titan's surface temperature -- but virtually every other substance I've seen mentioned as a possible component of its smog would be solid, which makes them much more likely to accumulate on the surface.

Correct, it looks and feels like candlewax.

Since Bruce posted this, I have been pouring through references, trying to figure out if a waxy surface could possibly produce the reflectivity and thermal inertia of Titan. A more challenging puzzle is posed by the pebbles and penetrometer data. It will be interesting to see if these features can be duplicated using organic, and possibly water-ammonia solutions.

I imagine that what we're looking at is a mixture of mostly ground-up water ice with a smaller amount of light-colored solid organics, rather than a concentrated top layer of the latter. Keep in mind that acetylene and all other solid organics are supposed to be produced at an incredibly slow rate -- about one micron total every 37 years, according to the estimate in Lunine's document -- which provides more than enough time for the methane rains, even at the rate of one rainstorm every few centuries on any given spot, to wash the extremely fine particles of such solid smog down and mix them into the layer of ground-up water-ice regolith (as well as for Titan's cryovolcanic activity, and the underground "hydrological" cycle that seems to be driven by it, to mix those compounds still deeper into the subsurface).

Interesting article found here:

http://www.astrobio.net/news/modules.php?o...order=0&thold=0

No signature of water - however the water may be masked by organics???

On a side note . . . I am finding it difficult to imagine that linear "dunes" of hydrocarbons (cat scratches) are being formed from a micron thick layer that is deposited every 37 years and then washed away with monsoons every hundred years or so. This theory just does not make much sense.

The more I look - these cat scratch features look more like "glacial crevasses" to me. That is they are not features that rise above the surface but *may* extend below.

Well, that means in 37 million years, you have a meter of organics. In 3.7 billion years, you have 100 meters of organics. If the current chemical cycles have been in place for a good fraction of an eon, then we can expect tens of meters of organics. And nothing says that the rate of production wasn't higher in the past.

One interesting Earth analogue to consider is that snow drifts can exceed, in amplitude, by a factor of ten or so, the amount of snowfall in a given location. Blanket an area with three feet of snow, and you can end up with 30 foot drifts. And that, presumably, includes no very long-range distribution (I doubt if snow falling on a spot ever ends up many km away). But organics on Titan may be globally redistributing the way dust does on Mars, so that a sum quantity sufficient to make a global layer 20 m thick could be 100 m thick in places... drifting into dunes... well, the math would be consistent even with VERY large dunes.

We have a lot to learn: What is the granularity and stickiness of Titan's sand/dust? What is the profile of materials and their densities? How much of the organics ends up subsurface, or settled atop channel beds, or downstream? Presumably if the organic dust is lighter than liquid methane, then it will not recede into the crust, but instead cover the surface.

I think we're seeing that some organics have washed into a sometime/once-wet basin that is basically a dry sea girdling the low latitudes. Channel beds, likely dry now, are also dark. And the dunes/megadrifts are rampant.

It looks to me like a basic picture is coming together, but the fine details will not be solved with Cassini. Think about how we're still learning a LOT about Mars with the MERs, which comprise the 4th and 5th landers, and MGS which was the third-generation orbiter at Mars (with two newer orbiters contributing now as well).

It's never seemed clearer that very soon in the sequence of Titan exploration, we need an aerobot to investigate surface properties of many areas: highlands (which includes many terrain types), cat scratch dunes, channel beds, the general "sea" bed, and of course, potential lakes such as Ontario that may be filled with liquid today. An orbiter cannot tell us about the mechanical and compositional properties of all of these surface units.

The "Teller" treshhold for impacts on Titan that could blast atmospheric gases permanently away from Titan is unknown to me. I am assuming the lighter gravity would lower it and the thicker atmosphere would raise it. If we assume it is around 100 megatons, more or less, has the radar instrument detected more than 1 crater probably resulting from an impact detonation that size or larger?

I'm thinking in the past, with 'more atmosphere' Titan might have generated more 'goo' in its' atmosphere to settle out to be lying on the surface.

Additionally, is the slow steady leakage of Titan's atmosphere into Saturn space confirmed?

The isotope-fractionation data from both Cassini and Huygens have confirmed earlier ground-based measurements showing that Titan has lost a lot of its original nitrogen atmosphere -- but it has NOT lost most of its initial level of atmospheric methane to space. That is, what methane it has lost has been totally replaced (unlike the nitrogen) with a flood of new methane from a much larger subsurface reservoir.

Those calculations indicating 300-600 meters of radiation-produced ethane, 100 meters of acetylene, and so forth are based on the assumption that the atmosphere's current level of about 3% methane is steady-state, being replenished at about the same rate that methane is lost into space or turned into those other organics. But if (as several theories suggest) Titan's atmospheric methane level has NOT been the same throughout its history, then it might have either much less or much more surface-deposited organics than Lunine's estimate.

As for "Exoplanet's" objections: good point, but there are two possible explanations. First -- as pointed out on the Antarctic-megadune URL mentioned by "jmknapp" in the "T8 Radar Images" thread below -- those "megadunes" in Antarctica are actually not high dunes at all, and the SAR images of them are NOT showing topographic radar shadows. They are, instead, wind-created patterns of relatively coarse or fine ice particles, which have different radar reflectivities -- the surface of their snow is actually close to flat. The same may well be true of the Cat Scratch "dunes" on Titan: they may just be wind-created patterns of different particle coarseness, in an almost flat layer of powdery organics that thus may not be very deep at all.

Second, as Rehling says, the Cat Scratch areas may be places where organic smog has been deposited and piled up by past flows of liquid methane -- that is, they may be lakebeds. On Earth, the particles of mud in dried-up lakebeds stick together to form a hardpan -- but that's just because a lot of the minerals in mud particles dissolve in water, and then dry out again to create a cement that sticks the grains together. (The same thing, by the way, may explain the astonishing lack of wind-blown soil movement on Venus -- but in that case, the soil grains are cemented together by the calcium compounds in them reacting with atmospheric trace gases that are corrosive over very long periods of time at such high temperatures. It now appears that Venus' soil is virtually all "crunchy", and in fact all the "rocks" photographed by the four Soviet landers appear to be hunks of such cemented soil.)

But we have no proof yet that the organics in Titan's solid smog particles dissolve the same way in liquid methane or ethane -- it may well be that the mud in Titan's lakebeds dries out not into hard mud, but just back into very loose, fluffy dustbeds. If so, we could have local lakebeds that have accumulated quite a deep layer of such smog particles over time (with only some of the accumulated smog particles being washed down into Titan's subsurface by the periodic rainstorms), and these deep "smogbeds" are loose and powdery between wetting episodes and thus especially susceptible to being blown around by Titan's winds.

Bruce, I arrived at a very similar scenario, but I had to sleep on it:

The ‘dunes’ could have formed at a time when the rotation and/or the prevailing winds were perpendicular AND Titan was much warmer: They are frozen in place, like the cemented - like you said, like the surface of Venus. I could go one step further, and insist the same event that changed the rotational direction also caused the heating, but that’s an unsupported stretch.

Edit: opps, wrong thread - this is not news, and belongs on the T8 thread...

Video Animation: Descend to Titan

At long last, a digest of my rendered video animation "Descend to Titan" made it to my website:
http://www.beugungsbild.de/huygens/huygens.html

--René

While the actual scientific papers on Huygens' (and, to a lesser extent, Cassini's) discoveries about Titan are trickling out at a slow pace, there have been several very good slide presentations of their findings which include a good deal of information that hasn't even been included in the relevant scientific articles on the slideshows' subjects yet. I've already mentioned Keller's and Tomasko's presentation on the DISR findings from last September's Titan Conference ( http://www.lpl.arizona.edu/titanconference...ts2/wrk.026.pdf ) and last November's CHARM presentation by the Cassini radar team ( http://saturn.jpl.nasa.gov/multimedia/prod...CHARM_RADAR.pdf ).

Let me add Dan Harpold's presentation on the GCMS rsults from last September's "Harsh-Environment Mass Spectrometry Workshop" ( http://cot.marine.usf.edu/hems/workshop/Wo...day/Harpold.pdf ), which includes several important charts and facts totally missing from Niemann's December "Nature" article ( http://www.nature.com/nature/journal/v438/...nature04122.pdf ).

Note in particular:

(1) The chart of the times and altitudes at which the different samples were taken (pg. 14). Jason tells us that the ion source that would have allowed CO measurements failed after only 23 minutes, which is apparently before the first GC sample was taken -- so Huygens got no CO data at all. ("EC" presumably stands for "Enrichment Cell".)

(2) The mass spectrum from the organic enrichment cell (pg. 18), which wasn't in the "Nature" article at all. Notice the regular pattern of peaks, indicating (like Cassini's high-altitude INMS spectra) that the instrument was detecting organics with different numbers of carbon atoms included, right up to at least C11.

(3) The post-landing increase in the amount of ethane and CO2 detected by the GCMS, as the heated inlet evaporated these out of the surface material over time (pg. 21) -- again, not at all in the "Nature" article. (The Huygens team seems awfully sure that what they detected -- both in the atmosphere and in the surface material -- was CO2 rather than propane, which has exactly the same molecular weight, and which according to preflight theories was supposed to be fully a thousand times commoner on the surface than CO2. Now, propane does actually evaporate at a considerably higher temperature than CO2 -- -42 C, versus -78 C -- but, still, their confidence seems odd. Maybe they determined this from ionized breakdown products; but it's another question I intend to ask Niemann if I ever manage to get in touch with him.)

(4) Last and definitely least, the smartass joke on pg. 22 (which I've seen elsewhere).

This is in the same ballpark, time wise, with the change in the permittivity of the 'soil' that began ~ 12 minutes after landing. Was the inlet heater close enough to the permitivity probe that it could have heated either the detector or the ground it was imbedded in?

I mentioned that over in the "New Huygens Descent Views" thread, in a May 19 entry. I don't know what it signifies, but the coincidence in timing is certainly interesting.

Some unexpected Huygens results at the ESA site :

http://www.esa.int/esaSC/SEM23SVT0PE_index_0.html

These results were published online yesterday in JGR-Planets as part of a special section entitled "Coordinated Earth-Based Observations of Titan During the Huygens Mission."

An interesting passage shows how their results correlate with radar data:

QUOTE

[24] Titan at large scales appears as a rather radar-dark moon with often a specular component suggestive of very flat but nonreflective terrain (studies at 3.5 cm by Muhleman et al. [1990, 1998] and 13 cm by Campbell et al., 2003]). The very localized Huygens bistatic experiment is compatible with this picture, although it is not clear if those properties can be globally generalized. Future observations by Cassini with its RADAR (including scatterometry and radiometry at various incidence angles and polarizations as well as SAR imaging) and conventional bistatic radio science (at S, X and Ka band [Kliore et al., 2004]) may clarify this.