Or frozen lakes of water ice?

Not likely, but possible. We have observed the temperature near Titan's south pole, and found that it is much warmer than expected. Likewise, the south pole of Enceladus, and the south pole of Saturn is warmer than expected from purely solar heating. Clearly there is an unexpected source of heating in these regions - whether or not there is a phenomenon that makes these events more likely in polar regions.

If the north pole is, or was in recent times, warmer than expected as well - much warmer, melting of surface moisture could result in great pools. (This does imply much of the surface of titan is something other than water, something with a lower melting point). If we can determine the refractive index of these 'pools' from (from reflective properties) we will find out. We also know, from radar and emissivity evidence that much of the surface of Titan is something 'other than water'.

The arguments against this scenario are significant, even using alternative physical laws: There is clearly methane in the atmosphere, and the expected temperature of the polar region is consistent with frozen methane or a methane/ethane mixture. But these preconceptions of what Titan SHOULD be made out of are currently driving the interpretations.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Other than your personal desire for it to be water ice, do you have any evidence that conditions on Titan are inconsistant with the methane ocean idea??

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"The facts gentlemen, and nothing but the facts, for careful eyes are narrowly watching." Isaac Asimov

Do these "lakes" even contain any liquid?

I completely agree, and the preconceptions run deep, dark areas in a radar image mean low reflectivity; a flat surface, not necessarily liquid.

Cheers.

Colored in water?
http://www.spaceflightnow.com/news/n0703/14titanseas/

"Cassini's radar instrument imaged several very dark features near Titan's north pole. Much larger than similar features seen before on Titan, the largest dark feature measures at least 100,000 square kilometers (39,000 square miles)."

Its a dark feature and they already assume its some liquid.

If they colored in the "lakes" to prove a point, I would say all of their assumptions are bogus.

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"Only those who attempt the absurd will achieve the impossible." - M. C. Escher

"Freedom is popular." -Ron Paul

My best guess is that the theories are correct about the methane cycle - I just want more evidence than dark radar. On the UMSF pages, someone pointed out that the shapes and scarpy boundries of the Titan lakes are more consistent with caldera than glacial pools. This would mean volcanoism of some kind.

Lots of voices talking about methane lakes doesn't improve the probability that they are just that. We need emissivity and spectral data before tying the knot on this one.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Maybe a good idea would be to look into the properties of the radars that are being used to look at Titan?

Specific frequency bands are used that are sensitive to specific compounds. See e.g. here, where Earth radars were used and it says:

These kind of radars are much more sophisticated that the "over the counter" radars that are used on ships to see if there are other ships in the neighbourhood, when you are sailing in the fog.

Did you read the link you gave us? It just being a dark region does not immediately mean it is a liquid. From the link you gave us I quote:

So, it is not just the region being dark, but there are other indications too, e.g. the smoothness etc. And it clearly says that there is no definite proof. But why not read some real papers on the topic, look for them on ADS or google, instead of "doing science" with press releases.

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Any comments in glorious red are to be considered in ModeratorMode.


善數, 不用籌策 (shàn shù, bù yòng chóu cè)
He who is good at counting, uses no counting tools
“A good scientist has freed himself of concepts and keeps his mind open to what is”
道德經, 二十七 (dào dé jīng, 27)

Dark radar reflections usually mean smooth...but not always. The lack of certainty invites speculation, so let's have fun with it!

...And if they determine the seas are made up of 'tholins'; the mystery just deepens, because nobody has been able to synthesize 'tholins'; that is, organic chemicals that duplicate the spectral signature of 'tholins' found elsewhere on Titan.

Which also discounts the assumption that the lakes are methane lakes - they may be a result of the atmosphere, but not the cause of it. It took us a long time to figure out what the atmosphere of Venus is, simply because no one even dreamed it would be 75% sulfuric acid. I remember being so disappointed when I was told this, I was certain there was something wrong with the data. Lunine expected oceans of methane. It is diffucult to bury a preconception.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

OK, bonehead question.

Define "Smooth" in the context of these bodies. Are they smooth relative to the rest of the ground? Are they mirror flat? Last time I checked, there's not a flat body of water on this planet of any substantial size. If Titan's got a thick atmosphere, winds of any measure, and reasonably active tidal cycle, those liquid bodies aren't "smooth" in any sincere measure of the word.

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The last time I felt a warm fuzzy feeling, I was informed by my doctor that it was just gas.

No, that is a good question. I have assumed 'smooth' would be smooth relative to the wavelength of the radar - which would be cm, not meters or km. Anyone?

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Maybe its my lack of technical background, but I was reading smooth to be the relative smoothness of the surface, given that it was a radar survey. For all we know, they could be methane/ethane, but more like Lunar Mare than Earth Seas.

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The last time I felt a warm fuzzy feeling, I was informed by my doctor that it was just gas.

Could they be smooth to the RADAR's 2-cm wavelength if the liquids are more viscous than the wind-battered water we're used to, being made of cold methane and (Google, don't fail me... here) products of methane photolysis, including ethane, acetylene and its polymers, other condensed organics, and the complex refractory photolysis product ‘tholin’?

(On the other hand, the drainage channels seem to be produced by a liquid that's not extremely viscous.)

We did see Huygens land on a fairly flat mud flat, studded with small ice rocks, just roughly maybe 5- or 10-cm, and as I recall the RADAR images of that territory had it fairly dark (maybe dynamic-range stretched, maybe hard to compare with the northern "seas"), surrounded by lighter highlands.

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0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 ...

What, specifically, are the relevant temperatures?Again, can we have some actual numbers please?

I mean "(much) warmer than expected" isn't very helpful, wrt water, if (for example) "expected" was 100K and "much warmer" was 150K. 150K is, indeed, "much warmer" than 100K!What is the triple point of methane? ethane? water?

I was wrong about Titan, the 'bright spot' did not show up on a subsequent passive radar pass:


The Southern Polar region of Enceladus on the whole, is ~20 degrees K warmer than the nominal 65 deg K temperature, with a hot spot that is at least 145 deg K; and may even exceed the freezing point of distilled water: 273K. We don't have enough resolution to know for sure.

http://saturn.jpl.nasa.gov/multimedi...m?imageID=2028
These are guideline values: Mixtures result in freezing point depression and boiling point elevation.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

I take that to mean that the answer to my question would be a "no."

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"The facts gentlemen, and nothing but the facts, for careful eyes are narrowly watching." Isaac Asimov

Well, the methane ocean idea can be discounted on the evidence so far; there are simply not enough lakes to account for the observed atmospheric abundances over Titan's assumed lifetime (billions of years).

More methane, hidden from view must be found somewhere to make the model consistent with observations again (volcanoes were hypothesized but haven't been seen yet). On top of that, the "lakes" have not been shown to contain any liquid yet, just a "smooth" surface, for comparison here is a radar image of a crater "lake"..... on Venus. Those would presumably contain molten lead to be a liquid. I'm not saying the methane is not present on Titan, merely pointing out that assumptions strongly influence what we "see"

Cheers.

While Huygens was on the surface, she detected a probable release of methane and benzene. Benzene has a vapor pressure only marginally less than water (BP= 80 C), but Huygens GCMS measure no ammonia (BP-34C); so the limited data is more consistant with methane lakes.

However (of course) there is a problems. Ions of solar reactions with Methane in Titan's atomosphere should have create a lot of polymerized organic structures - ring like structures like benzene. This should create a black and tar like surface, and not even the lakes look very dark in VIMs bandwidths.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

So if there are no hotspots ("much warmer than expected"), does that mean the answer to the question in the thread title (Are the Wetlands of Titan Water?) is "no"?