Hint of an underground ocean on Titan

[h2ouniverse]

<p>This article at SDC.</p><p>http://www.space.com/scienceastronomy/080320-titan-ocean.html</p><p>Makes th case for both an extended mission of Cassini, and for a Titan Explorer...</p>

 

[MeteorWayne]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>This article at SDC.http://www.space.com/scienceastronomy/080320-titan-ocean.htmlMakes th case for both an extended mission of Cassini, and for a Titan Explorer... <br />Posted by h2ouniverse</DIV><br /><br />From the article</p><p>"</p><p>The size of these shifts hints that Titan's crust and core have to be separated by a liquid ocean to allow the atmosphere to move the crust around. Titan is about 3,200 miles (5,150 km) in diameter. The hidden ocean may be 60 to 120 miles (100 to 200 km) thick and its ice crust may be 30 to 90 miles (50 to 150 km) thick, Lorenz said. Beneath that may be a few hundred miles of a heavier form of ice "that you get at higher pressures," he explained, on top of a rocky core roughly 1,800 to 2,100 miles (3,000 km to 3,400 km) wide.</p><p>This underground ocean is likely mostly water with a dash of ammonia. As organic molecules &mdash; the chemical ingredients of life on Earth &mdash; have been detected on Titan's surface, it may be they are in the ocean as well."</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[CalliArcale]

<p>Well, an extended mission for Cassini is practically a given -- which is why the team has already planned on getting the budget for it.&nbsp; ;-)&nbsp; But it would be WAY cool to see a mission sent specifically to Titan.&nbsp; Something more ambitious than Huygens.&nbsp; The article talks about doing something like that in 2017.&nbsp; *sigh*&nbsp; It's so hard to be patient, but you have to be when it comes to outer solar system probes. </p><p>That's an utterly amazing story.&nbsp; I was expecting something about detection by magnetic fields, but crustal shifts due to Titan's winds?&nbsp; Amazing! </p> <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>

 

[h2ouniverse]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Well, an extended mission for Cassini is practically a given -- which is why the team has already planned on getting the budget for it.&nbsp; ;-)&nbsp; But it would be WAY cool to see a mission sent specifically to Titan.&nbsp; Something more ambitious than Huygens.&nbsp; The article talks about doing something like that in 2017.&nbsp; *sigh*&nbsp; It's so hard to be patient, but you have to be when it comes to outer solar system probes. That's an utterly amazing story.&nbsp; I was expecting something about detection by magnetic fields, but crustal shifts due to Titan's winds?&nbsp; Amazing! <br />Posted by CalliArcale</DIV><br /><br />The extension is a given indeed. But some even consider an extension of the extension.</p><p>As far as Titan Saturn System Mission is concerned, actually the launch date would be in 2017 or 2018, for an arrival at Titan in 2028.</p><p>What would be really cool is that Cassini gets evidence for a cryovolcano, so that the balloon can sample the ejecta.</p><p>&nbsp;</p>

 

[h2ouniverse]

<p>More on NASA's site:</p><p>http://www.nasa.gov/mission_pages/cassini/media/cassini-20080320.html</p><p>&nbsp;and on newscientist:</p><p>http://space.newscientist.com/article/dn13516-titans-changing-spin-hints-at-hidden-ocean.html</p>

 

[3488]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'><font color="#ff0000">More on NASA's site:http://www.nasa.gov/mission_pages/cassini/media/cassini-20080320.htmland on newscientist:http://space.newscientist.com/article/dn13516-titans-changing-spin-hints-at-hidden-ocean.html <br />Posted by h2ouniverse</font></DIV></p><p><font size="2" color="#000080"><strong>Cheers Joel,</strong></font></p><p><font size="2" color="#000080"><strong>The rotation discrepancy has also been detected with Jupiter's Europa, which appears to lose a rotation every 1 million years, so every 500,000 years, Europa has opposing hemispheres facing Jupiter. </strong></font></p><p><font size="2" color="#000080"><strong>So Titan may be doing something similar. Very, very interesting, though with Titan it appears to be more of a 'rocking' motion, rather than de-spinning as with Europa.</strong></font></p><p><strong><font size="2" color="#000080">Also thanks for the article with the cut away diagram of Titan, they are difficult to find.</font></strong></p><p><strong><font size="2" color="#000080">I had heard from Dr&nbsp;Carolyn Porco, that Cassini could be extended to 2017, when Saturn & Titan reach their northern Summer Solstices (Saturn: September 2017 & Titan: May 2017).</font></strong></p><p><font size="2" color="#000080"><strong>Andrew Brown.</strong></font></p> <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[doublehelix]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>This article at SDC.http://www.space.com/scienceastronomy/080320-titan-ocean.htmlMakes th case for both an extended mission of Cassini, and for a Titan Explorer... <br /> Posted by h2ouniverse</DIV></p><p>No kidding.&nbsp; What awesome news.&nbsp; I'm excited to learn more!</p><p>-dh&nbsp;</p> <div class="Discussion_UserSignature"> <p><font color="#3366ff">doublehelix, Community Manager<br />Imaginova </font></p> </div>

 

[3488]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'><font color="#ff0000">No kidding.&nbsp; What awesome news.&nbsp; I'm excited to learn more!-dh&nbsp; <br />Posted by doublehelix</font></DIV></p><p><font size="2" color="#003300"><strong>I agree totally DoubleHelix. This is absolutely superb&nbsp;stuff & is already well within today's technological capabilities. </strong></font></p><p><font size="2" color="#003300"><strong>I will also attempt to find out more.</strong></font></p><p><strong><font size="2" color="#003300">Andrew Brown.</font></strong><br /></p> <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[silylene old]

<p>I know this isn't the ocean under Titan, but rather the biggest 'ocean' on the surface of Titan.&nbsp; I just wanted a chance to show the map (click to expand and see details)....</p><p>From Minton's excellent site on mapping and geography&nbsp; (please click the link for a few more Titan maps he has assembled): http://www.evs-islands.com/2008/02/titans-unnamed-methane-sea.html</p><p><br /><img src="http://sitelife.space.com/ver1.0/Content/images/store/6/0/4617db6d-c673-48d0-b032-3e00bc86c1e2.Medium.jpg" alt="" /></p> <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>

 

[3488]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'><font color="#ff0000">I know this isn't the ocean under Titan, but rather the biggest 'ocean' on the surface of Titan.&nbsp; I just wanted a chance to show the map (click to expand and see details)....From Minton's excellent site on mapping and geography&nbsp; (please click the link for a few more Titan maps he has assembled): http://www.evs-islands.com/2008/02/titans-unnamed-methane-sea.html <br />Posted by silylene</font></DIV></p><p><font size="2" color="#003300"><strong>Excellent stuff silylene, thank you very much.</strong></font></p><p><font size="2" color="#003300"><strong>Link below to the full size map of the largest Titan Methane sea.</strong></font></p><p><font size="2" color="#000080"><strong>http://www.flickr.com/photos/evsmap/2287372411/sizes/o/</strong></font></p><p><font size="2" color="#003300"><strong>Andrew Brown.</strong></font></p> <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[h2ouniverse]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I know this isn't the ocean under Titan, but rather the biggest 'ocean' on the surface of Titan.&nbsp; I just wanted a chance to show the map (click to expand and see details)....From Minton's excellent site on mapping and geography&nbsp; (please click the link for a few more Titan maps he has assembled): http://www.evs-islands.com/2008/02/titans-unnamed-methane-sea.html <br />Posted by silylene</DIV></p><p>hi Silylene</p><p>There are iterations about a potential&nbsp;lake-surface-sampling (or even a mini-submarine!) for the Titan Saturn System Mission. The point is that dropping a surface element in the polar region is expensive launch-mass-wise but the pressure is building up. Let's hope they succeed in getting this in-situ exploration orf the polar regions...</p><p>&nbsp;Regards.</p>

 

[3488]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'><font color="#ff0000">hi SilyleneThere are iterations about a potential&nbsp;lake-surface-sampling (or even a mini-submarine!) for the Titan Saturn System Mission. The point is that dropping a surface element in the polar region is expensive launch-mass-wise but the pressure is building up. Let's hope they succeed in getting this in-situ exploration orf the polar regions...&nbsp;Regards. <br />Posted by h2ouniverse</font></DIV></p><p><font size="2" color="#003300"><strong>Silylene has indeed bought something very special here, the first official map of a sea on another planetary body, an absolute first. I wonder&nbsp;if a submarine would see much, in a&nbsp;methane sea?<br /></strong></font><br /><font size="2" color="#003300"><strong>The Titan craft would presumably take up a polar orbit around Saturn first, then later on approach Titan then swing into a polar orbit, perhaps using aerobraking & thrusters??</strong></font></p><p><strong><font size="2" color="#003300">I take it the Saturn system element is a continuation of the studies Cassini has been carrying out?</font></strong></p><p><font size="2" color="#003300"><strong>A return to the Saturn system IMO, must include also, at least one close look at Enceladus, Dione & Iapetus, (I assume Enceladus is involved anyway, of course if TANDEM) if possible another flyby inbound of Phoebe, if the approach timing is right.</strong></font></p><p><strong><font size="2" color="#003300">Andrew Brown.</font></strong></p> <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[silylene old]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>hi SilyleneThere are iterations about a potential&nbsp;lake-surface-sampling (or even a mini-submarine!) for the Titan Saturn System Mission. The point is that dropping a surface element in the polar region is expensive launch-mass-wise but the pressure is building up. Let's hope they succeed in getting this in-situ exploration orf the polar regions...&nbsp;Regards. <br />Posted by h2ouniverse</DIV></p><p>&nbsp;</p><p>A sea sampling mission would be fantastic.&nbsp; I am hopeful when the ISS is done we will have much more $ for unmanned space exploration.</p><p>The mapped sea is about as big as Lake Superior.&nbsp; (also from Minton's site)</p><p><br /><img src="http://sitelife.space.com/ver1.0/Content/images/store/9/9/f915505c-620d-45fb-b964-727ec20d7b69.Medium.jpg" alt="" /><br /></p> <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>

 

[silylene old]

<p>And a composite view of Titan's north polar region:</p><p>http://www.flickr.com/photos/evsmap/2282737207/in/set-72157603958164230/</p><p><br /><img src="http://sitelife.space.com/ver1.0/Content/images/store/9/15/1910983b-2db4-4ac6-9ffd-df745cba78fb.Medium.jpg" alt="" /></p> <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>

 

[marsbug]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>.What would be really cool is that Cassini gets evidence for a cryovolcano, so that the balloon can sample the ejecta.&nbsp; <br />Posted by h2ouniverse</DIV><br /><br />Even if active cryovolcanoes are not found everything you could wish to learn might be locked up in ancient flows. And the same goes for the site of a large impact, some parts of the crater might remain liquid for centuries. Titan becomes more interesting with each new look!

 

[baulten]

Titan has always been my favorite moon in our solar system, along with Triton.&nbsp; Maybe it's the T's and the N's, but I can't help but speculate, especially in the case of Titan, that life exists in either its methane oceans or its water "mantle".&nbsp; I'm really hoping a Titan lander/balloon/etc. is launched soon (Soon meaning next couple decades)

 

[3488]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'><font color="#ff0000">Even if active cryovolcanoes are not found everything you could wish to learn might be locked up in ancient flows. And the same goes for the site of a large impact, some parts of the crater might remain liquid for centuries. Titan becomes more interesting with each new look! <br />Posted by marsbug</font></DIV></p><p>&nbsp;<font size="2"><strong>Hi marsbug,</strong></font></p><p><font size="2"><strong>There is already evidence of a Titan cryovolcano, Gensa Macula, 180 KM wide & pershaps 1.5 KM tall, complete with a 20 KM wide summit caldera & flows.</strong></font></p><p><font size="2"><strong>http://photojournal.jpl.nasa.gov/catalog/PIA09176</strong></font></p><p><font size="2" color="#000080"><strong>http://img397.imageshack.us/my.php?image=ganesamaculacryovolcanotv8.jpg</strong></font><br /><img src="http://sitelife.space.com/ver1.0/Content/images/store/15/3/2f86c205-0a7f-4000-b334-dc12af38b605.Medium.jpg" alt="" /></p><p><font size="2"><strong>80 KM wide summit area on Genesa Macula.</strong></font><br /><img src="http://sitelife.space.com/ver1.0/Content/images/store/2/9/a247d7b7-f0d6-4e23-89bd-6a391d0b8709.Medium.jpg" alt="" /></p><p><font size="2"><strong>Ganesa Macula, showing structure of eastern flanks.</strong></font></p><p><font size="2" color="#000080"><strong>http://img176.imageshack.us/my.php?image=ganesamaculacryovolcanobz4.jpg</strong></font><br /><img src="http://sitelife.space.com/ver1.0/Content/images/store/6/0/26d0d052-6155-48d6-80e8-a66fff97e237.Medium.jpg" alt="" /></p><p><strong><font size="2">Cryovolcanic flows from Ganesa Macula?</font></strong></p><p><font size="2"><strong>http://photojournal.jpl.nasa.gov/catalog/PIA06993</strong></font><img src="http://sitelife.space.com/ver1.0/Content/images/store/12/14/dcbce6d9-25d2-460c-aef5-31b4b253abc0.Medium.jpg" alt="" />&nbsp;</p><p><font size="2" color="#003300"><strong>Andrew Brown.</strong></font></p> <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[titanian]

<p>You point out something that almost everybody is forgetting: the possibility of a lifeform in the ( polar) ethane or methane seas. I follow you in that idea!</p><p>&nbsp;</p>

 

[JonClarke]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>You point out something that almost everybody is forgetting: the possibility of a lifeform in the ( polar) ethane or methane seas. I follow you in that idea!&nbsp; <br />Posted by titanian</DIV></p><p>Other than the ability of methane/ethane liquid to support complex chemistry, such liquids are much colder and therefore chemical reactions much slower than in water of even water-ammonia liquids.&nbsp; Which is why people are perhaps less interested in the possibility of life in methane-ethane.</p><p>However, the article points out that the proposed ocean is underlain by dense ice.&nbsp; This may well isolate the ocean fro the rocky core of Titan and prevent the formation of mineral deposits that provide energy sources i terrestrial geothermal vents.</p><p>Jon<br /></p> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[3488]

<p><strong><font size="2">Interesting Update here.</font></strong></p><p><strong><font size="2">Topography of Titan's arctic area & methane lakes.</font></strong><br /><font size="2" color="#000080"><strong>http://photojournal.jpl.nasa.gov/catalog/PIA10353</strong></font></p><p><br /><img src="http://sitelife.space.com/ver1.0/Content/images/store/15/1/dfd87d2b-0bd8-4ee2-91e5-dd3285d040be.Medium.jpg" alt="" /></p><p><strong><font size="2" color="#800000">Andrew Brown.</font></strong></p> <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[marsbug]

Thanks, I think titan is a strong contender for most interesting world in the solar system!

 

[CalliArcale]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Thanks, I think titan is a strong contender for most interesting world in the solar system! <br /> Posted by marsbug</DIV></p><p>&nbsp;</p><p>...which is impressive when you think about just how fantastically interesting some of the other moons are.&nbsp; ;-)&nbsp; Titan is incredible.&nbsp; So is Enceladus, especially with the tantalizing new discovery of complex hydrocarbons in the huge plume erupting out of it.&nbsp; Iapetus is fascinating, though probably quite dead.&nbsp; Going to Jupiter, Io is hellishly dynamic, and Europa has the promise of a subsurface ocean.&nbsp; (I'm gobsmacked that Titan also may have a subsurface ocean.&nbsp; I never would've expected it.&nbsp; But it's unbelievably cool.&nbsp; Perhaps these subsurface oceans are more common than we think.)&nbsp; And who can forget Triton?&nbsp; Weird, wild world, undoubtedly a captured KBO, orbiting backwards around Neptune and producing vicious winds and enormous geysers of liquid nitrogen.</p><p>The outer solar system has some astonishing worlds in it.</p> <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>

 

[silylene]

Another interesting hypothesis here http://www.scienceblog.com/cms/tita...rocarbons-says-stanford-researcher-20074.html

Titan may have subsurface ocean of hydrocarbons, says Stanford researcher

Saturn's largest moon, Titan, may have a subterranean ocean of hydrocarbons and some topsy-turvy topography in which the summits of its mountains lie lower than its average surface elevation, according to new research.

Titan is also more squashed in its overall shape--like a rubber ball pressed down by a foot--than researchers had expected, said Howard Zebker, a Stanford geophysicist and electrical engineer involved in the work. The new findings may help explain the presence of large lakes of hydrocarbons at both of Titan's poles, which have been puzzling researchers since being discovered in 2007.

"Since the poles are squished in with respect to the equator, if there is a hydrocarbon 'water table' that is more or less spherical in shape, then the poles would be closer down to that water table and depressions at the poles would fill up with liquid," Zebker said. The shape of the water table would be controlled by the gravitational field of Titan, which is still not fully understood.

Hydrocarbons are the only materials on Titan's surface that would remain liquid at minus180 degrees Celsius, the average temperature of the moon's surface. Any water would be frozen, making it plausible that instead of groundwater, Titan would have the equivalent in hydrocarbons.

The research will be published in a paper in Science and can now be read on the magazine's website.

 

[h2ouniverse]

Hi petet,

I can buy the existence of big underground hydrocarbons reservoirs (alkanofers). But a global ocean of hydrocarbons, uhmm! The argument of temperature is dubious, as temperature increases with depth as on any body and should exceed the meling point of water ammonia at some tens of kilometers below the surface, before the pressure becomes too high to form hot ices. To be global an "alkanocean" would have to be several kilometers deep (otherwise local variations in crust weight would disrupt its continuity), and that would then represent a colossal amount of hydrocarbons. Molten water-ammonia is a far more natural (less far-fetched) explanation for the apparent decoupling of the surface, given the abundance of H2O-NH3 in icy bodies. Occam's razor! And in addition supported by thermal analyses. ( see Sotin & Tobie article called in the first post of this thread)

Best regards.
I'm sure, petet, that silylene would also appreciate this topic, as you did. :mrgreen:

 

[silylene]

Silylene is a little dubious too, and is awaiting reading the publication in the upcoming Science article.