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Cassini Finds Evidence For Ocean Inside Titan

Posted by Soulskill on Thu Mar 20, 2008 07:28 PM
from the so-that's-where-it-was-hiding dept.
Space Science
Riding with Robots writes "NASA reports that by using data from the Cassini probe's radar, scientists established the locations of 50 unique landmarks on the surface of Saturn's planet-size moon Titan. They then searched for these same lakes, canyons and mountains in the data after subsequent Titan flybys. They found that the features had shifted from their expected positions by up to 30 kilometers. NASA says a systematic displacement of surface features would be difficult to explain unless the moon's icy crust was decoupled from its core by an internal ocean, making it easier for the crust to move. If confirmed, this discovery would add to the growing list of moons in the solar system that are icy on the outside and warm and liquid inside, providing potential habitats. We've previously discussed Titan's hydrocarbon lakes and potential cryovolcano."
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Related Stories

[+] Possible Cryovolcano Discovered on Titan 116 comments
Rei writes "NASA's Jet Propulsion Laboratory is reporting that the Cassini spacecraft has observed what appears to be a cryovolcano on Saturn's moon Titan. Given the absense of a global methane sea on Titan, the snail-shaped structure with what appears to be a caldera on top could explain how Titan's methane stays replenished. It could further explain the dry drainage channels discovered by the Huygens lander as being formed by heavy methane rainfall after eruptions."
[+] Pictures of Titan's Lakes 119 comments
sighted writes "For decades, scientists have wondered if the thick orange haze that shrouds Saturn's giant moon Titan hid lakes of liquid methane on the surface, but there was no way to confirm it, until now. The Cassini flyby of July 22, 2006 took these striking images and were released today."
Submission: Spacecraft Finds Possible Ocean Inside Titan by sighted (851500)
[+] Hardware: Cassini 'Tastes' Organic Material at Enceladus 70 comments
Riding with Robots writes "As previously reported, the robotic spacecraft Cassini recently flew through the mysterious geyser plumes at Saturn's icy moon Enceladus. Today, NASA released the preliminary results of the flyby, including some intriguing findings, such as organic materials 20 times denser than expected and relatively high temperatures along the fissures where the geysers emanate. 'These spectacular new data will really help us understand what powers the geysers. The surprisingly high temperatures make it more likely that there's liquid water not far below the surface,' said one mission scientist."
[+] Cassini's Primary Mission Ends, Two-Year Extension Begins 46 comments
wooferhound points out recent news that the Cassini probe has completed its original four-year mission and is beginning a two-year extended mission, which was authorized earlier this year. Cassini's first mission brought us a treasure trove of information about Saturn and its various moons. The new mission will target two of those moons in particular for further study: Titan and Enceladus. Quoting: "The spacecraft is extremely healthy and carries 12 instruments powered by three radioisotope thermoelectric generators. Data from Cassini's nominal and extended missions could lay the groundwork for possible future missions to Saturn, Titan or Enceladus. [The two moons] are primary targets in the two-year extended mission, dubbed the Cassini Equinox Mission. This time period also will allow for monitoring seasonal effects on Titan and Saturn, exploring new places within Saturn's magnetosphere, and observing the unique ring geometry of the Saturn equinox in August of 2009 when sunlight will pass directly through the plane of the rings."
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  • Titan is one of the most exciting bodies in our solar system. Having recently read Carl Sagan's Pale Blue Dot, he wrote a fair bit about the abundance of organic molecules on Titan. We seem to keep discovery more and more exciting things about this moon. It's probably still unlikely that there is life on it, but it sure would be interesting to send a probe in to it and see what we can discover.

    • Re:Exciting. (Score:5, Informative)

      by Anonymous Coward on Thursday March 20 2008, @07:40PM (#22814136)
      "it sure would be interesting to send a probe in to it and see what we can discover."

      We have sent The Huygens Probe [wikipedia.org] Before, but it was not designed to look for an underwater ocean. Lets hope they return with somthing else.
      • "but it was not designed to look for an underwater ocean"

        Well if you know how to design such a thing I think you could patent it an NOBODY on slashdot would complain about this patent.

    • Re:Exciting. (Score:5, Funny)

      by owlnation (858981) on Thursday March 20 2008, @08:31PM (#22814498)

      Titan is one of the most exciting bodies in our solar system.
      Of course, what you say is technically correct. But we really need a different way of expressing it, because when I read: "most exciting bodies in our solar system," I immediately thought: "Jessica Biel".

      I suspect I was not alone.
    • You might like to have a look at "Slow Life", by Michael Swanwick.
      http://www.analogsf.com/Hugos/slowlife.shtml [analogsf.com]

      It's a nice sci-fi novelette (that won the Hugo in 2003) about life in the deep seas of Titan.
      http://www.nicholaswhyte.info/sf/Hugo2003.htm [nicholaswhyte.info]
      http://www.locusmag.com/SFAwards/Db/Hugo2003.html#nvt [locusmag.com]

      "Is there life on Titan? Probably not. It's cold down there! 94 Kelvin is the same as -179 Celsius, or -290 Fahrenheit. And yet . . . life is persistent. It's been found in Antarctic ice and in boiling water in

      • "Is there life on Titan? Probably not. It's cold down there! 94 Kelvin is the same as -179 Celsius, or -290 Fahrenheit. And yet . . . life is persistent. It's been found in Antarctic ice and in boiling water in submarine volcanic vents."

        As usual, telling half the truth - a pretty important half. In both those places, life (as we understand it, which the life found was) cannot evolve, the conditions are too extreme. The life found there almost certainly evolved somewhere else and then adapted to those ext

      • "Is there life on Titan? Probably not. It's cold down there! 94 Kelvin

        Another way of putting it is that it is only twice as cold as the coldest place on Earth. Given nuclear power I think humans could live on Titan quite easily.

        I wonder if it has fossil oxygen or nitrogen dioxide? If such a thing could be found it might be possible to survive without uranium.

    • Titan is one of the most exciting bodies in our solar system.

      What about Jessica Alba?

      Your nerd credentials are hearby revoked.

  • life on/around gas giants (Score:5, Interesting)

    by sveard (1076275) on Thursday March 20 2008, @07:38PM (#22814110) Homepage
    Life ON gas giants seems like a big NO with what we currently know about the conditions required for life to emerge. But life around gas giants, on their moons seems plausible.

    What I'd like to know (read: what I'd like some slashdotter with the required know-how explain to me) is why are these moons hot on the inside, possibly hot enough for water ice to turn into liquid water. It's so incredibly far away from the sun. Is this caused by their size and subsequent internal dynamics?

    Also, aren't these moons constantly bombarded with radiation from their host planet's powerful magnetic field? Must be rough for aliens.

    • Re: (Score:3, Informative)

      by clem (5683)
      I believe that a gas giant's intense gravitational field can heat the cores of nearby moons.
      • If you were the size of a moon, the pressure you feel on the side you face your planet will be different from the pressure on the far side. Add to this an elliptical orbit around a planet and the core of the moon has enough activity to churn and produce heat. A lot of things are pretty crazy once you're the size of a moon.

    • Re:life on/around gas giants (Score:5, Informative)

      by mollymoo (202721) * on Thursday March 20 2008, @08:17PM (#22814416) Journal

      What I'd like to know (read: what I'd like some slashdotter with the required know-how explain to me) is why are these moons hot on the inside, possibly hot enough for water ice to turn into liquid water. It's so incredibly far away from the sun.

      The gravitational attraction between the moon and its parent planet is sufficiently strong that the modest changes in distance (and thus gravity) as the moon orbits are sufficient to repeatedly distort it by a 'significant' amount, which generates heat. It's kinda like a squash ball, which gets warm as it is repeatedly compressed during play.

      • Re:life on/around gas giants (Score:5, Informative)

        by Deadstick (535032) on Thursday March 20 2008, @08:56PM (#22814638)
        This is the same process that keeps one side of the Moon facing the Earth, and one side of Mercury facing the Sun. Both of them had some amount of spin long ago, but the squishing removes energy, and the only place that energy can come from is the rotational energy of the spin.

        The strength of the effect depends on the relative sizes of the two bodies, and the radius of the orbit, which is why most of the bodies in the solar system aren't tide-locked.

        rj

        • Re:life on/around gas giants (Score:5, Interesting)

          by isomeme (177414) <cberry@cine.net> on Thursday March 20 2008, @10:48PM (#22815598) Homepage Journal
          Mercury isn't 1:1 locked (one face always toward the sun). Rather, it's 3:2 locked (three rotations for every two revolutions around the sun). Thus, all of the surface gets periods of sunlight and darkness.

          The 3:2 resonance combined with Mercury's eccentric orbit does produce some interesting effects. As seen from certain points on the surface, you could start out in night, watch the sun rise, move a little way up the sky, turn around, set near where it rose, and then later rise again with a noticeably larger apparent diameter and travel all the way across the sky, then set, rise near where it set but now looking smaller again, turn around, and set again.
          • Aha, looks as if I'm 43 years out of date on Mercury...apparently that was determined in 1965. Thanks for the correction.

            rj
            • The really strange thing is that for a while it appeared that the rotation of Mercury was locked on Earth. We were just unlucky that the same face was pointing to Earth on every close approach.

        • Mercury facing the Sun

          Nitpick, it's locked into a 3:2 rotation. Here's the relevant wikithingy [wikipedia.org]

          Until radar observations in 1965 proved otherwise, it was thought that Mercury was tidally locked with the Sun. Instead, it turned out that Mercury has a 3:2 spin-orbit resonance, rotating three times for every two revolutions around the Sun; the eccentricity of Mercury's orbit makes this resonance stable. The original reason astronomers thought it was tidally locked was because whenever Mercury was best placed for observation, it was always at the same point in its 3:2 resonance, so showing the same face, which would be also the case if it were totally locked.

          • Yes, isomeme updated me on that. That condition means that Mercury is still dissipating spin energy, so I suppose it should eventually achieve 1:1 lock, even with the orbit eccentricity trying to keep it stable.

            rj
    • Tidal forces are kneading these planets like bread. There's a pretty good about of mechanical forces getting turned into heat.
    • Carl Sagan did some fantastic conceptions of life forms on gaseous giants such as living organisms that float like balloons in the upper atmospheres and feed off the biological matter floating around or like plants consume carbon dioxide and use the limited light of the upper atmosphere to create there own energy.

      Fascinating stuff to conceptualize life were we don't think it would exist. After we found it in the deepest/darkest places of our own earth we soon realized its terribly short sighted to limit li
      • ...from decaying protons.


        Slightly OT, but has anyone actually observed a decaying proton? Wikipedia says no [wikipedia.org].

  • Don't forget that the melting point of water *decreases* as pressure increases. The liquid core may well be damned cold!
  • While it is very likely that the interiors of a couple moons in the solar system have subsurface liquid oceans, that does not indicate high enough temperature at depth to consider the interior warm or hot or capable of supporting life. Over geologic time these subsurface liquids (which are thought to be predominantly H2O) have more likely formed through interaction with surrounding rock/metal. As H2O reacts with its surroundings and incorporates various impurities (salts, ammonia, organic molecules) into its structure the melting point is decreased to the point that a liquid or fluid condition is possible at significantly lower temperatures. Although in the case of Ganymede (Jupiter's fourth moon), which posses an internally generated magnetic field, a dynamo action similar to Earth's core may exist providing heat. Whether this is the case on Titan is yet to be determined. The massive amounts of organic components there make it harder to determine if there is an internal heat source or if the mixture of organic compounds are naturally stable at those conditions creating the lakes and cryovolcanoes previously mentioned.
      • Supporting life seems fairly easy. As you say, there are extremophiles right here that might be able to make a go in rather unpleasant (to most life) environments.

        The bigger question IMO is if life could readily start in such environments. I suppose it's short sighted of me, but I'd always thought of life originating in relatively normal environments and then migrating to those really hot/cold/acidic/basic/whatever places. Perhaps life can live on Titan/Ganymede, but would it need to be transplanted life
        • The problem is that normal is relative, in this case to our biology, generally. I we had evolved in another environment, that would be normal. We simply lack the information to know what environments life can start in.
  • And on the Titan internet's #1 news for nerds website, dot slash, they're posting about how there may be oceans on Earth :P Btw this is good cuz now astronaughts can go swimming cuz you know how they're always saying it's hard to get enough exercise in space with no gravity.

  • He just missed the news! (Score:5, Interesting)

    by aktzin (882293) on Thursday March 20 2008, @07:53PM (#22814244)

    Too bad Arthur C. Clarke passed away on Tuesday (Wed. in Sri Lanka), he would have been very pleased to have his suspicions confirmed like this. Then again, maybe he's hanging with Dave Bowman and HAL. In that case his response might be whatever a stylish English gentleman says instead of "Duh!".

    Rest in peace, Sir Arthur, and thanks for giving us "all these worlds."

    -- a sad fan who's enjoyed your books for over 20 years
  • Okay, I have a (dumb?) question for the rocket scientists here : since we have this nice rover design that we know works well on Mars, wouldn't it be interesting to send one on Titan to take a closer look?

    I mean I know it's a hell of a lot farther than Mars, but could anyone explain what are the biggest obstacles? Is it cost, accuracy, surface conditions, difficulties for reliable communication... ?

    Forgive my wild enthusiasm, but this is all very interesting and I either want us to send robots there

    • Re: (Score:3, Insightful)

      by tirerim (1108567)
      I think the biggest difficulty would be power. Our Mars rovers have been solar powered, but it's unlikely that that would work on Titan, since it's much farther from the Sun, and its atmosphere will block most of what little light does reach it, since it's basically opaque. All of our outer solar systems probes have been nuclear powered, and there might be difficulties in engineering that to fit on a rover and provide sufficient power. A rover would also have to contend with the weather (it rains methane
      • "will take an entirely new design."

        Not entirely new. The biggest problem seems to be, by far, the power source (for both general operations and communications).

        Landing is easier with a thick atmosphere. Temperature seems stabler than on Mars - a thick atmosphere supposedly helps with that too. The fact it rains could help with dust if there is any (but it could pose a problem to any rubber seals). The communications problem could be partly solved with an orbiting relay that could, in itself, do some studies
    • The Mars rover is solar powered. Titan is too far from the Sun to make that practical. So while a rover could be sent, it would have to be significantly different from the current designs.
    • Hmmm, it will sure make a big splash...
  • ...when you can't remember where you left your geographical features?
  • So now there's Europa and now Titan that have probable underground oceans, and oceans seem like good candidates for life.

    It would be interesting, if in the future, we find that most life actually forms on moons with oceans protected from the vaccum of space.

    Maybe out planet, with it's skin lain bare to the cosmos, is an exception for a life-harboring world. Maybe this is why we haven't heard from any other intelligent lifeforms; perhaps they all have severe agoraphobia and just freak-out when they send their first probes up through the surface.

    Let's hope the wouldn't suffer from the Krikkit [wikipedia.org] xenophobic mindset, or we might be finding out exactly how good we humans are at international...er, interplanetary negotiations...oh my, I certainly hope we don't have to find out!
    • "Maybe out planet, with it's skin lain bare to the cosmos, is an exception for a life-harboring world."

      That sounds very likely. Life on Earth depends on many things that seem to be rare - a strong magnetic field that protects us from our own sun, just right temperature - so that there is liquid water - just right atmosphere - so that there is no runaway greenhouse effect like Venus - and so on. With all the mass extinctions that happened here before we came, we could consider ourselves to be an extremely lu

  • "We believe that about 100 kilometers (62 miles) beneath the ice and organic-rich surface is an internal ocean of liquid water mixed with ammonia,"

    Liquid water mixed with ammonia? Sounds like pee to me! An ocean of pee, with an organic icy crust floating on top of it, the whole surrounded by an atmosphere of methane... This place sounds awfully much like the toilets of the solar system.

    I don't think I want to know what the core is made of..

    • So what if Titan has an ocean for a mantle. That doesn't mean it could be a better habitat for humans. At least in the short term, anyway. The crust is hundreds of kilometers thick on Titan. We can't drill that deep on Earth, where we can carry huge things around. If we wanted to get the water out of Titan, or Ganymede or Enceladus or Europa or any other water-filled moon, for that matter, we'd need to bring huge drills that weigh millions of kilograms; given our present technology, that is impossible, technologically, logistically, and economically. That doesn't mean Titan isn't a lucrative place to colonize; it's entire surface composition is very rich in potential rocket fuel. Once we establish an infrastructure on to harvest methane from its atmosphere or scoop stuff out of its seas and lakes, it would take half of the problem out of colonizing the outer solar system. But we'd still need to build an extremely expensive infrastructure, first.

      While I'm not very familiar with Titan, I know that Europa is constantly churning, with cracks opening up and being resealed again by water rising to the surface to freeze again, forming a new ice shell. It seems to me that all we would need to do is land a probe wherever there is "new" crust (ice) and sample the water there. We might be able to actually get a probe into the under-ocean one day, but for now, I think this would be the best approach. Then again, IANARSoNE (...Rocket Scientist or NASA Emplo

    • And also not get fried by large amounts of radiation.

    • Re: (Score:3, Insightful)

      by argent (18001)
      Science fiction: 2001, Star Trek, Lost in Space, ...

      Science: space probes, lunar landings, ...

      Engineering: solar power satellites, industrial microgravity, ...

      Industry: weather satellites, communication satellites, GPS, ...

      Science leads to spinoffs in multiple directions. Science fiction is one of them. New industries are another. We're in a Red Queen's Race here, and stopping all the science won't speed us up much, but it'll sure make it harder to keep running.

      If you're worried about wasted money, don't lo

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