Titan - Tholins on the Surface

[munkin]

The photo's from the Huyugens probe are incredible but the question that I keep asking myself is "where are the tholins?" If the probe landed on a hard crusty surface - what is the composition??? Theoretically, the texture of tholins at - 180C should be tarry. I really want to know the specifics - I am too impatient for generalities and don't want to wait months for scientific articles to be published <br /><br />Any ideas???

 

[thalion]

I remember when the tholins idea was a hot topic, as proposed by Sagan et al. They said it was possible that they could have built up to hundreds of meters of depth over the surface of the satellite and the lifetime of the Solar System. However, I think HST, Keck, and later Cassini imagery and radar info has dampened the prospects for such a global layer of tholins. <br /><br />Without more information on the composition of the surface, it may be impossible to know the probability of tholin deposition. I'm guessing the results of the Titan atmospheric analysis will give scientists enough information to place stronger limits on the possible chemical processes occurring on Titan.

 

[rogers_buck]

Humm, I'm wondering if there will be any signs of a "quench" in the audio or images from the surface. Seems like if you dropped a hot spacecraft onto a -150C frozen surface something would boil-off violently...<br />

 

[munkin]

With an atmosphere consisting predominantly of nitrogen, methane, acetylene, ethylene, ethane, hydrogen cyanide, carbon dioxide and very trace amounts of oxygen - these were supposed to combine via the energy of weak sunlight to produce larger molecules that would fall onto the surface and create the "tholin" layer. I have not heard this theory discounted but have not heard it discussed widely since Cassini arrived. <br /><br />My question then is this; where are the large molecules that are being produced in the upper atmosphere going if not to the surface? How are they being broken down? <br /><br />I have also read that the seas were supposed to be composed of liquid ethane - now it is methane?<br /><br />I would really like to see a serious discussion get started about the "chemisty" of Titan. As a final note - does anyone think that the color photo's are more "yellow" than "orange"<br /><br />

 

[munkin]

A few representations of articles that I found regarding tholins that were written either right before Cassini arrived or shortly after. This theory was still accepted within the last few months.<br /><br />http://shadow.eas.gatech.edu/~kdarmenova/titan.html<br />http://www.astronomy.com/asy/default.aspx?c=a&id=2057<br />http://www.innovations-report.com/html/reports/physics_astronomy/report-29344.html<br /><br />Tholins can only be dissolved on the surface of Titan in water and ammonia to create amino acids . . . .<br /><br />

 

[vogon13]

Perhaps UV degraded tholins are staining Iapetus via Saturn magnetotail interaction. Cassini should get a good look later in mission, maybe spectra will clear up ( or add to) mystery of composition. Will Cassini traverse magnetotail during simultaneous Titan passage? If it happens , I hope the right instruments are turned on. Probably wouldn't hurt to do this when Enceladus is lined up properly too.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[munkin]

I agree - some complex hydrocarbons *might * be escaping titan and staining Iapetus. I am not very well schooled on the orbital mechanics of Saturn's moon's, however. I hope that Cassini can figure this out in the future.<br /><br />From new information released from ESA today, what I find very interesting is the frozen "crust" that Huyugens landed on was comprised of water and hydrocarbons (also methane - I presume) - interesting. If the lander site is a fluvial location (flooded regularly - by tides I suppose) - then are the seas comprised of methane, ethane and water???? It was also mentioned that there was an organic sludge - was this above the crust or underneath?<br /><br />I hope that they have very competent organic chemists pouring over the data at this point. <br /><br />I strongly believe that the scientists do not have the chemistry right on Titan. If water has been detected in the crust above the brule - then the water at one time could possibly be deposited as a "fluid" mixed with the hydrocarbons and then froze when the "tide" went out. I know that water mixed with ammonia has a very low freezing point temperature - perhaps there is some sort of hydrocarbon that is reacting with the frozen water and keeping the water in a *liquid* form or melting the underlying water ice. At -180C - who knows what would be reacting with the frozen water. I am curious to see what the "creme" is made out of now that we know somewhat - the makeup of the Brule.<br /><br />Hope to hear from some of you that are familiar with organic chemisty. It has been more than fifteen years since I took organic chemisty II - so I am pretty rusty at this point.<br /><br />Help me out with this - please.

 

[claywoman]

Okay...here from a neophyte is a question sort of...<br /><br />I get from what I've read tonight, tholins is some sort of primoral soup from which life may have developed? Or have I got it wrong. Not being a science major, I have a lot to learn here, but I just need this cleared up so I can go forward....Sorry for inconveniencing you guys...

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>Will Cassini traverse magnetotail during simultaneous Titan passage?<p><hr /></p></p></blockquote><br /><br />Possibly. There is a planned sequence called Petal Rotation and Magnetotail Petal. Titan will be used to adjust Cassini's orbit, moving each petal around Saturn. This will include a petal smack in the middle of the magnetotail. <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>

 

[thechemist]

Tholins are complex chemical compounds containing carbon, hydrogen and nitrogen atoms, with molecular weights of approx. several hundred.<br />They have been produced in the laboratory when N2 (nitrogen gas)and CH4 (methane) react under an electrical discharge. This mimics Titan's atmosphere, where N2 and CH4 react under high energy photon bombardment.<br /><br />In the laboratory, there are indications that some of the nitrogen atoms are unsaturated (connected with double and triple bonds), which means that if (and it is a BIG if) they find themselves in a liquid mixture of water and ammonia, they will dissolve in it producing compounds with amino groups (-NH2). <br />I am not sure how the aminoacids will be produced, since these need -COOH groups, and there is not enough oxygen in Titan (current knowledge, very soon to be updated by Huygens results).<br /><br />That is why it is important to wait for the scientific results from Huygens, before starting to theorize. We have to find definite experimental proof of tholins on Titan first. Then we have to find experimental evidence that water/ammonia sludges do exist on Titan's surface, and oxygen is also available, in order to make aminoacids (a model for the creation of acidic groups has also to be proposed). <br />Only then we can talk of a premordial soup containing aminoacids on Titan's surface.<br /><br />Keep in mind also that a frozen (-180 oC) soup of aminoacids is not very useful in creating life. Higher temperatures in Titan's past might need be invoked.<br /><br />Patience, everybody please. The Huygens data will be coming up soon, let's all give ESA a break to assess them. <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[munkin]

One of the actual experiments regarding tholin production in the atmosphere of Titan can be found here:<br /><br />http://www.stanford.edu/group/Zarelab/pubsweb/pub%20links/721.pdf<br /><br />Electricity was used only to simulate the photoelectric energy from the sun. Cryrogenic temperatures were approximating the extremely cold surface of Titan under various atmospheric pressures.<br /><br />Please note that the probe measured the surface temperature at exactly -180C. This is a big difference than -200C as other forum members have pointed out to you before in relation to the solid, liquid and gas phase of both methane and ethane on Titan.<br /><br />*Trace* amounts of oxygen have been found in the atmosphere of Titan. One of the previous articles that I used as a reference mentioned this.<br /><br />ESA has confirmed that the probe encountered water at the surface. I don't have the exact press release in front of me at this time but I believe it was released yesterday.<br /><br />We will probably hear more at ESA's Friday morning press conference. <br /><br />Can't wait <br /><br /><br />

 

[munkin]

Thanks for explaining the tholin theory so clearly. <br /><br />I can't wait until this Friday's press conference - hopefully we will have more of an idea of the organic chemisty on Titan (what is so fascinating is that it has been going on for 4.6 billion years!!!)<br /><br /><br /><br />

 

[robnissen]

"Titan has very likely always been very cold."<br /><br />To a moral certainty, the ENTIRE surface of Titan has not ALWAYS been very cold. At the very LEAST, parts of Titan's surface would become quite warm when hit by a large meteor. Although I am not a chemist, it is my understanding that Tholins can react quite quickly while water is in a liquid state. Over the billions of years, there has undoubtably been thousands of impacts that would have created enough heat to melt ice to react with Tholins. Now, whether such reactions have occured or not, we do not yet know.

 

[igorsboss]

Will Titan always be cold?<br /><br />When Sol enters the red giant stage, might Titan enter a haitable region?<br /><br />Perhaps we are looking at a prebiotic environment.<br /><br />Anybody have a packet of seeds handy?