Unveiling Titan

[farmerman]

If I heard correctly on a news channel today that nasa has come out and said that titans surface is dry, that there are no oceans or lakes. bummer.

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>Molten ice flow, or a “river” as it is known as by English speaking life forms here on earth.<br /><br />Pardon my skepticism but this just can’t be true can it?<p><hr /></p></p></blockquote><br /><br />I understand there are some exotic forms of ice which behave as viscous liquids, but I always thought they only existed under pressure. I could be wrong; it's just stuff I've heard in passing, and I'm probably not remembering correctly. I know I didn't understand it at the time, so take this with a grain of salt. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[CalliArcale]

Wait a minute, I just thought of something else. Ice can flow like a liquid, even on the surface. When it does, it's called a glacier. On a normal human timescale, it's basically a solid. But on a geologic timescale, it flows relatively quickly, and almost as if it were a liquid. Perhaps the Cassini team is thinking along those lines? <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[CalliArcale]

I'm thinking along those lines too, although I don't think Titan is under as much tidal stress as Europa. It'll be interesting to see what they find out in the future; these observations don't cover much of the moon, so there's lots left to look at. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[chew_on_this]

Any thoughts that the cloud formation in the southern hemisphere could be fed by a geyser due to it being summertime in the region? Doesn't it come and go with the seasons?

 

[yurkin]

Hi Calli<br /><br />A glacier is a frozen ice flow; a river is a molten ice flow. Since on Titan ice is the natural state of water liquid water is therefore molten. <br /><br />When I picture of what this must look like I imagine those videos on Pillow lava from Hawaii that’s flowing underwater. The outside instantly freezes when it contacts the water but the inside is still molten and it seems to grow forward like toothpaste.<br />

 

[voyagerwsh]

Hydrocarbons alkane group (methane and ethane, etc.) has very low melting point. At average of 90 K melting point they could mix with water ice and flow on the surface of Titan which has average surface temperature of 95 K. Sludge and slush like flow may even be lighter and slicker on the surface of heavier atmospheric pressure (1.5 Bar) with smaller gravity. <br />

 

[silylene old]

First off, relatively pure ice at -180C doesn't flow. It's HARD. At -70C ice is as hard as quartz rock (6-7 on the mohs scale), and it gets even harder. So glaciers wouldn't flow very easily, if at all.<br /><br />Now it's true that compressed ice will melt; and it's true that glacier flow could occur via repeated brittle fracture mechanisms. This would require modeling and experimenttation to see what ice thickness at Titan's low gravity would be required to compress enough to melt at -180C. My guess is that the icepack would have to be a score of kms thick for this to occur. Whether glaciers could flow via a brittle fracture mechanism depends again on the ground slope, the mass of ice, the moduli of ice at -180C, and the very low gravity. Again, I think that the ground slopes are too gradual (based on the radar elevation differentials), the ice is too cold, and the gravity too small for this to be a realistic mechanism.<br /><br /><font color="yellow">As long as temerature doesn't fall below the freezing point of the organic compound the mixture stays semi-liquid and is in a form of dense sludge... sort of like lava. This mixture would be probably gradually losing water due to its precipitation on solid surfaces </font><br /><br />First, most organics are <i>not</i> miscible with water. Water and organics separate into layers, and so the water freezing temp of the water layer would not be significantly reduced. Some oxygenated organics (short chain aldehydes, ethers and ketones; alcohols) are water miscible, as are some N- containing organics. Are these oxygenated or N-containing organics present on the surface? I don't know - good question! Next, nearly all (pure) organics themselves freeze well prior to -180C and are solid. Mixed organics would have a lower freezing point, but I suspect most any organic stew would still form a hard glass at -180C. I base this on lots of lab experiences working up reaction messes while using cold traps.<br /> <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[peteb]

Here's a discussion of cryovolcanism on Titan and other icy satellites:<br />http://www.es.ucl.ac.uk/research/planetaryweb/undergraduate/dom/weathering_titan/chap7.htm

 

[silylene old]

thanks PeteB, I hadn't seen that. Interestingly, it's very close to my discussion above, except that the authors emphasize NH3-H2O hydrates or other gas-clathrates and discuss the possible ammonium salts which might be present.<br /><br />I didn't think we had detected enough NH3 in the atmosphere of Titan for me to consider this as the main composition of the clathrates. Titan is 90% N2, 10% organics of which methane is the primary organic component. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[hansolo0]

I just saw a quick news report on fox news yesterday that said analysis of Titan seems to indicate there was no flowing liquid there. Disappointing , if true, but I haven't seen any other reports of this here or otherwise?<br />

 

[peteb]

silylene-<br /><br />One of the the things from that site that interested me was the fact that water-ammonia (+_ other components) fluids have viscosities similar to those of silicate magmas on Earth. <br /><br />

 

[alexblackwell]

Thanks for the link, Pete.

 

[alexblackwell]

Published online today in <i>Geophysical Research Letters</i>:<br /><br />Ma, Ying-Juan; Nagy, Andrew F.; Cravens, Thomas E.; Sokolov, Igor V.; Clark, John; Hansen, Kenneth C.<br /><b>3-D global MHD model prediction for the first close flyby of Titan by Cassini</b><br /><i>Geophys. Res. Lett</i>., Vol. 31, No. 22, L22803<br />10.1029/2004GL021215<br />17 November 2004<br />Abstract

 

[yurkin]

So we’re looking at a flow whose average temperature is 90K. <br />That’s starting to get a little to cold for life. There are a lot of chemical reactions that won’t work at that temperature. Fascinating never the less.<br />

 

[remcook]

RADAR surprises from Titan<br />(astrobio.net talks with Ralph Lorenz)<br /><br />here

 

[alexblackwell]

Thanks for the link, remcook. This <i>was</i> an informative interview.

 

[alexblackwell]

PIA06520: Smog Moon

 

[alexblackwell]

A Titan of a Mission<br />Science News Online<br />November 20, 2004

 

[alexblackwell]

Successful Huygens test: last before separation<br />ESA News Release<br />November 23, 2004

 

[alexblackwell]

Hovering Over Titan<br />Credit: NASA/JPL/Space Science Institute<br />Released: November 23, 2004 (PIA 06141)

 

[alexblackwell]

Cassini Shows Grandeur of Two Saturn Moons<br />Jet Propulsion Laboratory<br />November 23, 2004

 

[thechemist]

Cassini's improving view of Titan<br />Nature.com <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[centsworth_II]

If my understanding is correct, the yellow ellipse is Huygens' approximate landing area. If so, we will hopefully get a look at the "island" of light material during the decent. Huygens may land in the light material, the dark, or in the border area. It would be great to get extreme closeups of the border region as Huygens decends! <div class="Discussion_UserSignature"> </div>

 

[thechemist]

Maybe Santa will be a bit late in bringing his gifts this year. Let's say around the 14th of January ? <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>