[X] My Assistant

[belleraphon1]

"There's nothing like data to mess up a good hypothesis".

Are there currently planned observations that will be key to our understanding?

This is a really exciting time as we watch the story unfold.

Whoo-hoo!

-Mike

All...

First I would also welcome rlorenz to UMSF's. I cannot imagine how satisfying it must be to have designed apparatus that has grounded on another world. Your insights will be greatly appreciated but understand that some things you must keep close to your chest.

As for Mike's question about currently planed observations.... looking at the http://cassinicam.com/titanflybys/ link it seems that there are three south polar passes coming up that will help detail what is currently happening on the hotter side of Titan. 10/02/07, 12/05/07, and 12/20/07.

Do we have a system here where the summer poles have thunderstorm activity driven by the solar insolation while the winter collects liquid pools in the dark? I really want to see what higher resolution data has to say about the south pole.... RADAR/ISS/VIMS.

Craig

[ustrax]

Nice of you to point that out....

Knowing (as we do now, 2 years on) how much darker the lakes are at N polar
regions, I'd have to guess these particular features in TA (50-ish north)
are more likely to be dried-up lakebed-type features than presently-filled lakes
as seen at higher latitude...

Welcome!
Dried-up for good or waiting for the next season?
In the paper there is a reference to asphalt, OK, maybe not a proper comparison...
Are we looking at places that once dried, formed a solid surface layer? What kind of stuff would originate that? Would it be like if someone hasn't cleaning Exxon Valdez mess?

[belleraphon1]

From the T27 mission description document.

"Inbound and outbound RSS bistatic scattering observations of Titan’s surface will provide information about the dielectric constant, nature, and roughness of the region probed. This RSS bistatic observation is in the deep southern hemisphere, over one of the ver
 large dark regions shown in the imaging data.  In the north, these large dark r
gions have turned out to be seas and lakes"

Interesting.

Craig

[Juramike]

Knowing (as we do now, 2 years on) how much darker the lakes are at N polar
regions, I'd have to guess these particular features in TA (50-ish north)
are more likely to be dried-up lakebed-type features than presently-filled lakes
as seen at higher latitude...

Welcome! And I look forward to hearing all of your insights and opinions! It must be also satisfying to see so much discussion and interest (here at UMSF and elsewhere) regarding your research.

Regarding the lakes and dried up lakes, it's amazing that now we have the "pattern recognition" that we can start identifying them from previous SAR passes.

Is there a latitude cut in the N where dark lakes no longer exist and then where the dried up lakes are no longer easily identifiable?

Is it similar in the S?

-Mike

[ngunn]

Great to see you here Ralph Lorenz. Your input will be extremely welcome. It's a wonderful time for Titan fans but we need all the expert guidance we can get with understanding the wealth of new and often baffling information.

[Webscientist]

I also bought the book "Lifting Titan's Veil"in 2004, a great source of inspiration and a great basis for the evolution of our understanding of Titan. They should have called Titan's landing Site "Ralph Lorenz" instead of Curien
We have now new certitudes: there are clouds and notably what looks like a giant hurricane engulfing Titan's north pole.
I guess that there is a close relationship between the lakes, the seas and the cloud. If I understood well, this cloud is made of ethane and methane.
As a result, the bodies of liquid are likely filled with methane and ethane.
My question is: how do those two compounds interact ? do they mix? Do they superimpose as liquids?
What might be the appearance of the pools made up of these liquids, exclusively?

http://www.titanexploration.com

[Littlebit]

As a result, the bodies of liquid are likely filled with methane and ethane.
My question is: how do those two compounds interact ? do they mix? Do they superimpose as liquids?
What might be the appearance of the pools made up of these liquids, exclusively?

http://www.titanexploration.com

You will find some of this chemistry in Ralph's book.

Ethane [HHHCCHHH] and Methane [HHHCHHH] are infinitely mixable, and as a mixture, the boiling point is raised slightly and the freezing point depressed: Any methane liquid on an ethane solid would 'pull the solid' into solution, like water on sugar. There would also be desolved nitrogen gas in the mixture from Titans heavy atmosphere. At such low temperatures the surface tension should be quite high, and the liquid flow a lot like water.

Pure ethane-methane liquid would be clear in visible light, but have strong peaks in the infrared... unfortunately these are of the same frequencies as the methane and ethane in the atmosphere, so this will be difficult to confirm.

In a lake of methane and ethane, you would expect to find many other longer chain carbon compounds. This is because UV light from the sun and cosmic rays, will break carbon-carbon and carbon hydrogen bonds, forming longer chains and rings. This is why the lakes are much more likely to be dark and oily looking. This is also why the much lighter surface of Titan remains a puzzle - if it is covered with organics, it is much like paraffin wax. But virtually all known natural processes would cause multi-colored ring and chain organic structures - black tar and coal-like. There has been speculation that the 'sand' of titan is 'water encapsulated in organics', but this makes no sense, from an organic synthesis prospective.

Edited to add 2Hs

[ustrax]

At such low temperatures the surface tension should be quite high, and the liquid flow a lot like water.

Thanks littlebit, that was very visual!
Now, not quite off-topic but more off-science, in the last week I dreamt twice with Titan...
In one of the dreams there was this incredible new images arriving IN COLOUR and where you could see the lakes filled with water-like liquid and where you could even see...check out the detail...small pebbles in the bottom...
On the other dream there was even more detailed views...I was looking through some images where this red tiny spheres colonies attached to black rocks were being discussed to the proof of life on our favourite Saturn's moon...

[Juramike]

There has been speculation that the 'sand' of titan is 'water encapsulated in organics', but this makes no sense, from an organic synthesis prospective.

The complex organic molecules are probably functionalized and not just simple and branched hydrocarbon greaseballs. These functionalities (nitriles, esters, amides, alcohols, carboxylic acids) are going to be polarized compared to the hydrocarbon parts (alkyl, alkene, alkynyl).

Like dissolves like.

When the organic molecules are mixed (emulsified) with methane/ethane and water. The polar functionalities of the molecule wil orient in towards the central water droplet. And the more greasy part will be oriented to the outside towards the hydrocarbon solvent (methane/ethane). The water molecules in suspension would be surrounded by oriented organic polymers in a micelle structure. This is similar (but with opposite orientation) to how soap dissolves grease in in water: except that the polar part of soap molecules orients toward polar solvent (water) and the greasy part of the soap molecule orients towards the non-polar grease.

[On Titan, soap would be needed to get "water soluble stains" out of your clothes during the methane wash cycle. And yes, you could probably still use your favorite laundry soap on Titan, the micelles would just be inside out compared to on Earth].

Micelles are usually very small structures. Much smaller than grains of sand. They are usually one molecular layer thick. (OK, biological cells are technically two layer thick micelles: polar layer on outside, non-polar in middle, and second polar layer facing cytosol). I would not be suprised if the micelle like structues would form complex and yukky emulsions in Titan's lakes.

But the sand grains would probably have a different origin.

Most likely on Titan, the sand grains first started as tiny chunks of ice that were eroded off and rolled around and got coated in organic goo. At the molecular contact with the ice surface, the more polar parts of the organic molecules would orient towards the water, while the hydrophobic parts would be to the exterior. In this case, the coating would be much, much more than a molecular layer thick.

Then again, a dried out emulsion mess just might form a powdery or sand-like structure. (Like dried soap flakes)

-Mike

[stevesliva]

Any methane liquid on an ethane solid would 'pull the solid' into solution, like water on sugar.

Given the news that the lakes potentially have steep rims, I have been wondering whether the lakes themselves are excavating those escarpments. I was also wondering whether the excavation might be seasonal, while in the summer(?) solids precipitate out of the lakes while methane evaporates out.

Since the seasons are so long on Titan, it's interesting to speculate what sort of mini-ice ages the Earth would have with similarly long seasons, and what short-lived features would appear in the spring as the rains return after a 10 year winter. The liquid flow would be compounded by the melting of all that stored up solid. I've gotten confused, though... do the rains come in winter on Titan?

[ngunn]

Some of the lakes are in fairly deep hollows but that doesn't mean they actually have steep shorelines. Lake 20 appears to have dried or drained out, leaving part of the area of its topographic basin significantly less radar-dark. It is definitely worth considering wave action as a potentially significant process on Titan, but it alone cannot produce the steep sided basins, let alone stop them filling up with sediment. There's something important here that we haven't yet sussed.

[JRehling]

Some of the lakes are in fairly deep hollows but that doesn't mean they actually have steep shorelines. Lake 20 appears to have dried or drained out, leaving part of the area of its topographic basin significantly less radar-dark. It is definitely worth considering wave action as a potentially significant process on Titan, but it alone cannot produce the steep sided basins, let alone stop them filling up with sediment. There's something important here that we haven't yet sussed.

Something about what you said reminded me of the Great Basin (more or less Nevada, USA), and places where jagged relief was washed by sediment until what we have left are sawtooth ridges with flat plains between them. A lot of former jagged sawtooth is below the sedimentary plain. At some point, there were lakes in Death Valley, with the lake and the surrounding plain very flat, but the ridges off in the distance extremely high.

One thing that makes Titan quite unlike Earth is that it's just intrinsically drier. Nevada might be a decent analogue for certain areas on Titan.

I wonder if the dampness at the Huygens site indicates that the equatorial girdle is perpetually wet, and is a sort of "sea" of dampness, where the methane table is at just about exactly the surface. Where would Earth's water be if we had only a few percent as much as we have, so that the oceans weren't there? Would we have a lot of Caspian -style lakes, or would we have larger mushier areas? I think we have the answer: the Caspian, etc., are wet and surrounded by dry land, not big bogs. Maybe the ambient conditions on Titan are amenable to bogs instead of lakes.

[ngunn]

Maybe the ambient conditions on Titan are amenable to bogs instead of lakes.

I think that's dead right. I think of the smust as a 'hygroscopic' material - 'alkanoscopic'? (oh I give up) that is very resistent to drying. So, dampness everywhere except right on the surface at low latitudes, and rather slow drainage from rain-saturated 'mud-banks' at higher latitudes. And the black stuff definitely moves. If it can be sculpted into dunes by a light wind then it can definitely be transported 'en masse' by a flood.

[nprev]

I've favored the "cold pre-Mariner 2 Venus" analogy with respect to Titan for quite some time now, mostly because the liquids seem to be concentrated at the poles. However, how to explain the apparent washout areas (dry seabeds?) at the equator without monsoons, which I'm beginning to suspect may be much less likely if Titan is indeed relatively methane-poor as JR suggests? Maybe they are artifacts of a richer era, like the riverbeds of Mars but better preserved by the dense atmosphere, benign weather conditions, and limited solar radiation exposure...

[Juramike]

Do y'all think that the smust in the equatorial zone is methanoscopic by inclusion of methane in pore spaces (which means it could go in and out freely like a sponge).

Or is it more permanent? With the ice incorporating methane into a type I clathrate structure? This would be a one way trip for the methane - it would not easily come back out of the lattice.

This abstract discusses the massive amount of methane (and N2 that could be incorporated into an ice clathrate structure): http://www.lpi.usra.edu/meetings/lpsc2005/pdf/1123.pdf



Perhaps Titan had a massive "Wet Season" which formed all the geology, then the methane got sucked up and locked away in the equatorial sands, so now we see Titan in a Dry Age.

I think (help! panic! I need an expert opinion here?) both scenarios could explain the releasing of methane when the Huygens probe landed.

Could kinetic data of methane release after the probe hit reveal the difference between a desorption or a clathrate breakdown?

-Mike