Liquid Lakes confirmed on Titan!

Latest issue of Nature provides evidence that Ontario Lacus at Titan's South pole is definitely liquid.

Space.com article: http://www.space.com/scienceastronomy/080730-titan-lake.html

-Mike

Brown et al. Nature 454 (2008), 607-610. "The identification of liquid ethane in Titan's Ontario Lacus." doi: 10.1038/nature07100.

(Pay for article: abstract here)

VIMS spectral analysis of lake, "beach" (annulus in text), and adjacent areas are consistent with ethane and higher order alkanes.
[Pretty hardcore spectral analysis. For those interested, here's a quick primer.].

-Mike

A large dark patch at the end of the summer season! I assume there has been a lot of evaporation in that area. A large cloud formation had been identified relatively close to this small sea or big lake. A fortiori, it results from the evaporation of this pool.
I wonder how is the rain: drizzle, heavy showers with lightning ? Maybe that in the north polar region, there is drizzle with so little sunlight coming in but in the south pole, there may be the opposite. I'm not a meteorologist but it seems to be a logical reasoning to me.

Could be, the lake could help to increase the humidity.

But I wouldn't drink the "lakes empty in summer, fill in winter" kool-aid just yet...


Drizzle in winter, heavy showers (no lightning) in summer. Summer polar climate on Titan is a lot like Arizona in the summer, bone dry with occasional downpours. Light showers don't happen very often (unless it is a small storm away from the main storm system) because the rain evaporates before it hits the ground. Heavy rain has a greater chance of hitting the ground.

We have to be careful with how we interpret data at the south pole. We have only gotten a few snapshots and we really need more to establish how the climate works down there. And VIMS has only one flyby with good images of Ontario. We will need more to establish if lake levels are rising or falling (if we can at all from VIMS data).

I just wanted to call attention to the newly-released VIMS detection of Ethane within Titan's Ontario Lacus. Prior evidence for lakes, while compelling, was entirely circumstantial. The lakes look really dark in RADAR, and in ISS, and show lake-like morphologies. What we've found is the smoking gun that unambiguously identifies the lakes (well, this one at least) as being liquid, and composed at least partially of ethane. Presumably the ethane is in solution with liquid methane, but we can't identify methane since those lines are entirely saturated by looking through so much of it in the atmosphere.

Anyway, you can read either the press release or the paper in Nature. I've posted a copy of the paper on my website as well.

- VIMS Jason

It has been mentioned elsewhere (and there is a great post on http://planetary.org/blog ), but thank you for posting the paper!

Ack -- just looked at the last page and didn't see Juramike's post from yesterday. My bad !

- VIMS Jason

Thanks for the post. This announcement illustrates the ideal strategy for using RADAR, ISS, and VIMS for complimentary science. ISS is great at providing an overview of a region, identifying targets of interest based on unique morphology and albedo at 938 nm. VIMS and RADAR can then adjust their pointing when they have prime coverage at closest approach to observe these unique features.

Now, we just need to look at the southern part of Kraken Mare

This should have its own thread anyway. Juramike's post and other posts after that moved to this topic.

I dunno if this is always the *ideal* strategy, but this particular observation was specifically targetted by VIMS because of the ISS observations of Ontario Lacus on Rev 9. So your strategy worked to perfection in this instance, at least, I would say!

- VIMS Jason

Thanks Jason for that link to the Nature paper.....

This news article has some great VIMS images of the beach at Ontario Lacus.
http://www.dlr.de/en/desktopdefault.aspx/t.../86_read-13154/

Does VIMS have a site with updated image products?

I've walked the beaches of the Great Lakes (live near Lake Erie). Would love to walk this beach.

Craig

Hey wow, that color one is one of mine, I think. Cool. Didn't realize that the European release was distinct.

Regarding the Beach, although we call it that, I don't think that it really is a beach. Geologists define a beach as "wave deposited sediments", which I'm not convinced these are. Standby for more on this; just submitted a paper to Icarus last week about what it and the outer, bright ring might be and what that means.

- VIMS Jason

Jason..

Thanks for the clarification regarding the 'beach'. Look forward to the paper in Icarus, if I can just find an open source to access it.

Still wanna walk it...

Keep us informed.....

Craig

Or better yet, stand by for T49 when we will get altimetry on it. My guess is the whole thing
('beach' and all) will be 10^-3 or lower slope (i.e. a tidal flat) but we will see a radiometric
transition where the present 'waterline' is (presumably the residual ethane - with some amount
of methane having seasonally evaporated)

Of course, RADAR data is merely 'circumstantial' per your earlier post, maybe that isnt of
interest ....

"Hey, you got SAR RADAR data in my VIMS?"
"And you got VIMS in my RADAR!"
"Oh wow! Tastes great!"
[Voiceover] "Two great flavors in one..."
(Shameless apologies to Nestle's Peanut Butter Crunch)

Unfortunately, to really nail things down, RADAR + VIMS + "something else" is probably going to be necessary to fully tease out the composition of the lakes and lakeshore.

"something else" = :

in situ GC (maybe not sufficient)
in situ GC-MS
and the Queen MacDaddy of them all, in situ stopped flow injection HPLC - 2D NMR (a 1H-13C heteronuclear correlation experiment)
lander with full suite of analytical experiments above
sample return (for the trace complex organics)

There will need to be something to figure out the mechanical properties (inferred by volume scattering) of the lakeshore stuff and some type of in situ chemical separation (the GC part) and some type of separated component analytical detection. The really hardcore stuff will be required for any funky organic species. (Unless there is a massive library of Titan-like compounds with which to try to compare analytical fingerprints discrete structures).

I think of Titan as a massive natural products isolation and determination exercise (like where they grind up some rare deep sea sponge and try to extract and determine all the bizarre molecular structures). Just figuring out one of the complex structures made by critters (palytoxin is one of the more complex ones) is usually the subject of one or more papers.

"Tholins" as a catch-all phrase still seems way too generic: it would be like referring to enzyme structures as "proteins" or other complex structures as "alkaloids".
"Hydrocarbons" or "alkanes" is equally unsatisfying. Which ones? What's the proportion?

-Mike

I would not waste a 2D 1H/13C HETCOR for the liquids in the lake, they will probably be much simpler structurally than the stuff left out after evaporation on the "shore", so 1D NMR would be enough. I'd save the time for hardcore 2D of the "shore" organics, although without an LC pre-separation step, specific component identification would be difficult, as Mike points out.

Who knows, maybe by 2020 (or later ?) some sort of NMR-on-a-chip will be available to fly on a Titan mission. There is some progress in the field recently.

Am definitely looking forward to that; I think that it will be of great use!

- VIMS Jason

Good question. NxCxHx? I don't know if 'tholins' means nitrates, nitroamines, nitriles, mercaptans, esters, ammio acids, or aldahydes. Would someone please go get a sample, and bring it back to the lab, pronto!

I think it's be nifty if someone could find a way of making this stuff at scale.

If Aldrich sold "Titan tholin" I'll bet there's whole bunch of HPLC jocks and NMR jocks just dying to use their favorite column packing and acronym bearing pulse sequence to seperate and identify the components.

[The HOHAHA experiment is one of my favorites acronyms, my graduate advisor was famous for getting the Fully Uncoupled Coupled Overhauser Uncoupling Protocol (FUCOUP) into the Journal of the American Chemical society]

-Mike

...don't DO that, Mike, I'm dyin'!!!

Well, at least we know that your advisor is to blame now. I'm gonna go up to Hollywood tonight & advise the stand-up clubs that PhD organic chemists are the shizz-net for pure entertainment value...

(BTW, not mocking you at all, of course...very much appreciating you!!!)

EDIT: Closest I ever came to a coup like that happened way back when working for NOAA. We had a very small boat designed for rapid reaction to ecologically harmful events. I proposed the name "Fast Action Response Team" boat, and it damn near stuck...

Ah, yes -- reminds me of the famous horce race call, when the low-rated Hoof Hearted came from behind to win...

Speaking of which, would these tholins have any particular scent if they were to be introduced to a terrestrial atmosphere (that was then sniffed into a human nose)?

-the other Doug

Followed by Ice Melted.



I'll get my coat.

...and perhaps some air freshener?



-the other Doug

I am told that it can smell like burnt paper (the fresh stuff will oxidise somewhat in air). A lot will depend
on temperature - if cold you'll condense a lot of the other photolysis products with it, which will smell
like your usual suite of petrochemicals.

Making it in quantity would be nice (it typically is synthesized as a film deposited on the inside of
some glassware - often a pain to scrape out) to do some mechanical properties experiments.
So far the most I've done with it is try to scrape my fingernail with it (to my student Catherine Neish's
horror*) to estimate Mohs hardness..

* Carl Sagan, who did a lot of experiments with tholins - he named the stuff after all - and
Reid Thompson in his lab, and a secretary in that group at Cornell, all passed away before their
time of cancer-related illnesses, leading some to suspect tholins as being bad for you. That
said, Bishun Khare is still hale and hearty.

What needs to be clarified is that everything made on earth is actually a tholin-analogue, TA. There are 2-3 ways of making TAs, and since the produced TAs differ in solubility, they might as well differ in chemical composition. I have a student trying to do some NMR work on a small TA sample I got, and I advised her to treat it as being dangerous (gloves and fume hood work), since we don't really know what's is in there. That said, I don't believe the Sagan rumors have any solid foundation. But one needs to be precautious. I would not touch the thing with my bare hands.

I'm often confused by the definition of 'tholin'. I thought it was the stuff they made in the lab, making tholin an analogue for Titan aerosols...hmmm

Is it possible for you to ban yourself for that? Damn elitists...

Re thiolins: My understanding of them has always been that they are a pretty much random mixture of organics of varying complexity, all the way from the basic "-anes" to polymers. So, yeah, I bet they can stink up a place, and certainly should be treated as hazmat if for no other reason then that you really do not know exactly what you have. Many complex organics are carcinogens (though I agree with TheChemist that the Sagan rumor is unlikely), if not outright toxic.

Frankly, if I was a Titanian "miner" 500 years from now, I'd insist on triple hazard pay, the best health & life insurance available, and a one-month on, three months off somewhere with clean air schedule. (There'd better be a bar there as well!!! )

Indeed it is better to be cautious. But I wonder if it is actually any worse for you in a
skin contact or inhalation sense than
a) moon dust
Mars dust

At least it has been shown that some bacteria can metabolize tholin

Comment ?

Yeah, you would need air pressure in environments at greater than 1.6 bars to ensure that all the nasty chemicals in the environment (*cough* benzene *cough*) isn't inhaled.

Titanian dust could be carcinogenic...

...or it could help in the war against cancer.

Logic:

1. Pyrimidines (and pyrimidones) are formed in spark tholin experiments
2. Adenine (of ATP fame; it is business part of the "A" in the DNA ATGC bases) is a pyrimidine
3. Kinases are key enzymes in the control of cell processes (growth, metabolism, reproduction, gene control, etc.)
4. Kinases bind and use ATP to transfer phosphates to control other enzymes
5. Other pyrimidines can behave like ATP bind the ATP binding site of the kinase and shut down a kinase
6. Controlling kinases can lead to cancer therapeutics.

(Points 2-6 have been clinically validated. Example: Gleevec (a kinase inhibitor, actually a less selective kinase inhibitor than they first thought) is a great therapeutic for the treatment of Philadelphia gene positive Chronic Myloid Leukemia (CML))

I have seen (and worked on) many kinase inhibitors that I would say "yeah, I wouldn't be suprised to find something like that on Titan." 7-azaindole derivatives, which seems to be everyones "secret kinase scaffold" seem a farily likely possibility on Titan's surface; they are small CN heterocyclic fused rings with few, if any, oxygen atoms)
[F'r example: BMS patent here]

That being said, noway would I want to roll around in Titan muck and indiscrimanently and non-selectively inhibit my kinome, nor any other enzymes I happen to need. (And intercalating my DNA or chunking up my liver enzymes isn't hight on my List of Things To Do on Titan, either.) But I do think Titan as a potential source for "wierd funky molecules made by natural processes" the same way I view rainforests (and deep sea sponges) as sources for interesting and potentially useful therapeutics.

-Mike

(Could we get Big Pharma to sponsor a sample return mission?)

Did someone say there would be a radar "image" (SAR) of Ontario Lacus on T49?

No. try *reading* the post - I said we would get *altimetry* on Ontario on T49.

There will be SAR of it later in the tour.

No need to get sniffy.

Don't take it personal -- that's just Ralph being Ralph.

Guilty as charged. But that's a feature, not a bug....

OK so I will admit that I am a complete ingenue in the area of planetary geology and organic chemistry compared to some of you on this forum, but how much of Titan's surface will be mapped by SAR radar by the extended mission's end?

Will the Northern Polar lakes - the radar imaged ones that have awed the laypeople like me - be getting the VIMS treatment to determine their chemical composition like Ontario Lacus in the South?
And how much of Titan will be covered by altimetry data? Do we have any idea as to the difference in elevations on the moon yet?

Will we be able to say, by the mission's final end, with almost complete certainty that there are liquid ethane lakes on Titan, in both the North and South polar regions?

And what about the early hopes of the imaging cameras catching a "glint" reflection from a Titanian sea? Will this still be possible to achieve with the lakes?

I'll take a crack at these two. The problem with the northern lakes so far is that Titan is right now nearing the end of southern summer. So the Sun isn't up yet in the northern lakes. So far ISS and VIMS at shorter wavelengths are able to see past the day/night terminator by using the scattering to our advantage -- at the northern lakes the sky is bright from scattered sunlight, and we use that light to take some pictures on the night side. But there's just not enough light, and what light there is is suspect, such that VIMS observations of the northern lakes will have to wait a year or two until they are more reliably lit. So the answer to your question is that yes, the northern lakes will hopefully eventually get a high-res and high-signal-to-noise VIMS observation, but give it a couple of years into the Cassini Equinox Mission (extended mission).

The prospects for a glint are slim. Because the lakes are at the poles, you'd have to look at a really oblique angle in order to see a glint. And if we're at those kind of emission angles ISS can't see through the smog. And VIMS would rather be looking at the new territory below it rather than looking for a glint. But based on the VIMS Ontario Lacus observations I think that we're seeing specular reflection of light from the sky off of the lakes. Here's an Earth-based example of this from Crater Lake in Oregon:



See also ngunn's gross pool image. I talk about this some more in my DPS talk, which is supposedly archived somewhere but I can't find at the moment . . .

- Jason W. Barnes

Hi Jason. The DPS presentations seem to be still available via the attached index page. (By the way I'm glad somebody was following my OT ramble on the other thread. This is probably a better place to continue that discussion so I will post some further thoughts and queries here shortly.)

OK here goes. Using polarisation of reflected skylight to study Titan's lakes is of course up against the ever-present problem of scattering by the atmospheric haze. This gets worse at oblique angles, so first I ask:

Q1 - What is our best estimate for the Brewster angle for Titan's lakes at VIMS and ISS wavelengths?

Whatever the optimum viewing angle it's certain that only a small fraction of the photons reflected by a lake make it out through the haze unscattered. Hence it is necessary to ask also:

Q2 - how much does forward scattering by the haze mess with the plane of polarisation? (Rather a lot would be my guess.)

And:

Q3 - Is the small fraction of unscattered photons sufficient to yield observable contrast between lake images taken with different polarising filters? (My guess again: slight but maybe just observable. Certainly not like the college pond pictures!)

If the answers to all three questions leave any grounds for optimism then the potential prize could be great: processed images of lakes (or at least shiny areas) produced selectively from unscattered photons. This could potentially increase the resolution of shoreline features well beyond what the infrared instruments (ISS especially) are able to achieve at Titan by other means.

Q4 - Does any of this make sense?

This is an interesting question that former Cassini Project Scientist Dennis Matson brought up to me after my DPS talk. To be honest I haven't thought at all about the polarization for the specific reason that VIMS doesn't have a polarizer on-board Cassini. So for me, even if there is an effect, we can't see it. Does ISS have a polarizer? They might have a better shot.

- original VIMS Jason

Yes they do. Three 60 degrees apart on one camera and two orthogonal on the other. Looking at all those sets of three matching ISS images taken during the recent cloud-hunting campaign, at first I thought that that was what they were doing, but no. Then I began to wonder why not, especially for the shots that include Kraken Mare? So I guess my question is really one for them. Somehow I just assumed that VIMS would have a polariser too - sorry, my mistake. Thanks for taking the trouble to reply anyhow, and for the fascinating DPS presentation.

It does, but we haven't used it to the best of my knowledge for Kraken Mare but I will put out a note about that.

The recent observation was intended to catalog cloud features on Titan.

Great - keep us posted if it's going to be tried.

So if there's ethane, and probably methane, in these lakes, could there be more complex alkanes in smaller quantities? Could the same processes make propane, butane, pentane, etc.? Also, is there a chance for other organic molecules - glucose, amino acids, etc.? Is there oxygen available to form those sorts of things?

Yup!



Absolutely! (and benzene and other polyaromatic carbocycles and heterocycles).


The precursors seem pretty likely to be present. They may be all stuck together through some CN type bonding arrangements in a tholin-type structure. (Amidines, diimides, etc.) A good basic hydrolysis should free up some things and convert some of these hydrolytically-unstable bonds into amides.

Oxygen gas is not available (save for some oxygen radicals rarely formed from radiation hitting a clathrate cage)

The best source of oxygen is water, which is everywhere. The problem is getting the frozen water to react. Needs heat or some other energy source. Which is why lightning would be an exciting discovery.

-Mike

[quote name='ngunn' date='Oct 31 2008, 07:21 PM' post='129852']
Hi Jason. The DPS presentations seem to be still available via the attached index page.

Thanks NGunn - It's great having people like you around! I've been wondering about these talks and how to find them again but just haven't had the time. Hugh.

I really can't let that stand. It's actually totally unlike me to be up to a trick like that!! Someone else here located the page in a google cache (whatever that is) and tipped us off that it might be a good idea to save it before it disappeared. I wish I could remember who.

Will the real clever clogs please step forward...