Astronomy Magazine is posting a four part series on their website of an edited transcript from a talk Cassini Interdisciplinary Scientist and Titan Atmospheric Guru Jonathan Lunine gave at the Nasa Director's Seminar in January. The talk covers preliminary results from Huygens and results from the RADAR instrument from October.<br /><br />http://www.astrobio.net/news/article1466.html<br /><br />You can also watch the talk (for those with Real Player) or read a list of highlights on my blog.
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His theory of ammonia mixing with water, keeping the water below the surface and liquid is fascinating!!!<br /><br />His whole theory of ammonia is going to blow my head off here....wish I was a science major sometimes, but then I'd have to take more math...no thanks...hehe<br /><br />klath-rated methane????
The fact that Titan's orbit is not circular suggests that Titan's sub-surface ocean has not frozen. Secondly, flows of viscous material (methane at 94K/1.5atm is less viscous than water at STP so it can't be that) were found by Cassini RADAR SAR. Now no one is saying they have found an active flow or a hotspot as you alude to, but these flows could very well have been active in the recent past.
<font color="yellow"> Titan's orbit is not circular suggests that Titan's sub-surface ocean has not frozen.</font><br /><br />How non-circular are we talking about here? Could it just be some intercalation with the Titan’s atmosphere and the Saturn system that is causing what looks like a tidal effect?<br /><br />We’ve had 4 flybys of Titan but I think its going to take a few more then that to pin down how much of a liquid layer we are talking about.<br /><br />Still I don’t see any way to account for the observations without some kind of volcanic activity.<br />
Titan's orbital period and Iapetus's orbital period very close to 5:1 ratio. Also Titan and Hyperion periods in ratio of 4:3. We might be seeing some 'forced' eccentricity as we do with Io, although at a much reduced intensity, with respect to the effects.<br /><br />Also, NASA TV ran a lecture from some of the Cassini team members re results so far, on 3/2/05. Might want to watch and see if it repeats. It's on my Tivo, and I haven't had time to watch it all the way through yet, will post any thunderous relevations I note. <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>
The tidal dissipation of the global ocean freezing would have quickly circularized the orbit. True, Titan is near some resonances with other satellites but the tidal interaction would not be enough to cause this much eccentricity.
The orbit is very well known, and I should hope confirmed. That is what the observation indicates- a subsurface ocean. No ifs, ands, or buts. If you'd like, I'd be more than happy to provide a link to what the "real" scientist believe to be true.<br /><br /> Not too many things involved in planetary sciences need to be proven "beyond a reasonable doubt" and it's doubtfull they ever will ever be in a lifetime. Scientists go a lot by indications. This indicates that. If that isn't good enough for you than TS. If it's good enough for the guys who know a helluva lot more than you or I, it's good enough for me. Capiche?
<br /><font color="yellow">'Scientists go a lot by indications." <br /><br />Whatever that means. Indications are occ. good for hypothesis formation, but confirmation and substantiation are still needed. A fact which you sidewise avoid....</font><br /><br />The orbit <font color="blue">indicates</font>a subsurface ocean. What's so hard to understand about that? I don't need a treatise on the scientific method everytime you reply. You seem incredibly stuck on this -160 surface temp. Good god man, that's surface temp! We're talking subsurface ocean. Let's see the links that say this is not <font color="red">indicated</font>
The surface temperature on Io is 120K, but yet Io has silicate lava flows.<br /><br />Skeptism is a good thing, but so is the ability to go out on a limb if the data fits. True, surface temperatures preclude standing pools of ammonia and water but yet we see flows of viscous material that is consistent with an ammonia/water mixture. Is that proof? No, of course not. But it is intreguing enough to investigate further and find further evidence to back up that indication.
"The orbit indicates a subsurface ocean"<br />As far I can understands from Jason's summary of the talk, the reverse is the case:<br />a subsurface ocean could explain the orbit.<br /><br />But this is not the only possible answer (a big comet impact could also make an orbit eccentric for instance)<br /><br />Jason, could you explain why the eccentric orbit is an argument against a global surface ocean but a subsurface ocean does not suffer from the same argument?<br />sorry...I haven't read that much about titan's surface. I'm an atmosphere guy <img src="/images/icons/smile.gif" />
on that same note... the Earth has liquid silicate flows! and 15 degrees C is FAR less than the boiling point of rock
To be honest, two arguments are possible. One is that as Titan a global sub-surface ocean, 300 km down, formed, but has not frozen. If Titan's global ocean froze, the eccentricity would be dissipated and the orbit would be circularized. The other possibility is that Titan did not differentiate very well and that it never had a global sub-surface ocean. Since there was no ocean to freeze, it couldn't dissipate the eccentricity.<br /><br />Huygens GCMS and Cassini INMS has found the radiogenic Potassium product Argon-40 in the atmosphere but not other argon isotopes. Cassini RADAR and Cassini ISS (tentatively) have found surface features that have been interpreted as cryolava flows. Combine this with the lack of large bodies of liquid methane (save for a few ephemerial lakes) thus requiring a sub-surface methane source and the general lack of craters, and you have a recipe for a pretty active world. This would suggest that Titan has differentiated. If Titan is differentiated (and later flybys can confirm this), it is highly likely that a sub-surface ocean exists (and this can also be confirmed by later RSS flybys).
Steve, <br /><br />did you listen to that lecture at all? I doubt it, because what you've stated here, is not what the experts said...you know, the men and women who actually worked on the project?
VolcanoPele <br /><br />I think there is one final hypothesis to explain the orbit. It’s that Titan doesn’t have a subsurface ocean but a surface or near-surface ocean. Zandu could be an ocean that has just the top meter or so frozen. The black material that flows or rains down to it floats on the surface and is semi solid could account for the observations. It could be solid and broken up on the surface like pack ice. The ocean' wouldn’t generate a smooth radar reflection, nor would it be visible reflective. If the ocean wasn’t very deep then there would still be craters on it like the few seen.<br /><br />Maybe more flybys would detect if the Zandu region is lighter the other hemispheres of Titan. The tidal forces might be strong enough to account for the eccentricities observed.<br /><br />Steve<br /><br />But concerning the subsurface ocean I think one would really have to go out on a limb to try and come up with a contradicting theory.<br />The atmosphere of Titan shows clear signs of activity indicative of geologic activity. And you can’t have geologic activity without a molten sub surface region.<br />
Steve,<br /><br />Io's diameter is 3630 km vs. Titan's 5150 km. You are correct that Titan is almost twice as large as Io - yet, Titan's core is still possibly radioactive and hot as scientists have seen from the c isotope ratio of the methane and nitrogen in Titan's atmosphere. Both must be replenished and the only way to do so would be through volcanism. <br /><br />I like to think of Titan in this way. If you have ever been to Yellowstone in the winter - you know that many hot springs are at or slightly above the boiling point of water yet the surface temperature is possibly -30 C (it can get very cold in Yellowstone
). That is almost a 210 degree difference from air and surface temp to what is actually rising from a local hot spot on Earth.<br /><br />Here is a great article explaining that Titan's nitrogen rich atmosphere is being produced cyrogenically from ammonia:<br /><br />http://physorg.com/news3111.html <br /><br />If you want to refute any of the information in the above article please direct your comments to the scientists involved in the research. I would love to hear what they might say about your own personal theories about Titan being *FROZEN SOLID*.<br /><br />
). That is almost a 210 degree difference from air and surface temp to what is actually rising from a local hot spot on Earth.<br /><br />Here is a great article explaining that Titan's nitrogen rich atmosphere is being produced cyrogenically from ammonia:<br /><br />http://physorg.com/news3111.html <br /><br />If you want to refute any of the information in the above article please direct your comments to the scientists involved in the research. I would love to hear what they might say about your own personal theories about Titan being *FROZEN SOLID*.<br /><br />Like I said, show me the links or you're just clucking like a chicken, not that it hasn't happened before. The soggy "ground" where Huygens landed pretty much spoils your <font color="red">belief</font>in Titan being frozen solid.
The problem with Xanadu being a sea is that the "crust" couldn't be a meter or so deep given the landforms seen within Xanadu.
A paper is currently in press in Icarus on deriving an internal model for Titan from the high eccentricity of Titan's orbit by Tobie et al.
Some interesting items:<br /><br />MEDIA RELATIONS OFFICE<br />CASSINI IMAGING CENTRAL LABORATORY FOR OPERATIONS (CICLOPS) SPACE SCIENCE INSTITUTE, BOULDER, COLORADO http://ciclops.org media@ciclops.org<br /><br />Preston Dyches (720) 974-5823<br />CICLOPS/Space Science Institute, Boulder, Colo.<br /><br />For Immediate Release: March 9, 2005<br /><br />CASSINI IMAGES REVEAL AN ACTIVE, EARTH-LIKE WORLD<br /><br />Saturn’s hazy largest moon, Titan – a body long held to be a frozen analog of early Earth – has a surface shaped largely by an Earth-like interplay of tectonics, erosion by fluids, winds, and perhaps volcanism. <br />So reports the Cassini imaging team in today’s issue of Nature, in their first published presentation of findings from images of Titan gathered since last July.<br /><br />Titan is about the same size and density as Jupiter's largest moon, Ganymede. Unlike Ganymede, though, it probably has not undergone tidal heating – a well-known internal engine for modification of planetary surfaces. For these reasons, Titan was expected to have a surface at least as old as Ganymede’s and pocked with at least as many large craters. Over the past billion years, Titan should have accumulated as many as a hundred craters, 20 kilometers (12 miles) wide and larger, across its entire surface.<br /><br />Yet, that is not what is seen in the images of this world Cassini has obtained so far.<br /><br />Dr. Elizabeth Turtle, imaging team associate in the Lunar and Planetary Lab at the University of Arizona in Tucson (and co-author on the paper in Nature) said, “We’ve only just begun exploring the surface of Titan, but what’s struck me the most so far is the variety of the surface patterns that we’re seeing. The surface is very complex, and shows evidence for so many different modification processes.”<br /><br />Images collected over the last eight months during a distant flyby of the south polar region a
Just another one of steves' pre-conceived (or shall I say ill-concieved) beliefs falls by the wayside.<br /><br />http://space.com/scienceastronomy/050608_titan_volcano.html
Yup, the odds of life on Titan have just increased, albeit IMHO they are still quite low. Nevertheless, with organic compounds and a heat source (assuming this article is correct), life is at least a possibility.
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