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Space Science

Lake spotted on Titan? 197

Posted by CmdrTaco from the ultimate-polar-bear-swim dept.
jahead writes "It looks like a lake has been seen on Saturn's moon Titan by the Cassini probe. But don't get too excited yet. As mentioned by Elizabeth Turtle in the article, it could also be a dried up lake that left dark deposits."
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Lake spotted on Titan? More

Lake spotted on Titan?

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  • Act now!!! (Score:5, Funny)

    by 1967mustangman ( 883255 ) on Wednesday June 29, 2005 @12:34PM (#12942252)
    And now, for a limited time only, I can sell you lake front property on said lake on Titan for the astonishingly low price of $20 an acre!!!

  • What would be the significance of this? (Score:5, Insightful)

    by bc90021 ( 43730 ) * <bc90021 AT bc90021 DOT net> on Wednesday June 29, 2005 @12:35PM (#12942260) Homepage
    I'm not trolling, I'm curious. Surely, liquids exist in space, and surely they must pool? If it were a *water* lake I'd say that'd be something (life!?), but on a planet where there's likely methane rain, there's likely methane lakes.

    • Re:What would be the significance of this? (Score:5, Interesting)

      by bc90021 ( 43730 ) * <bc90021 AT bc90021 DOT net> on Wednesday June 29, 2005 @12:39PM (#12942301) Homepage
      What do you moderators not understand about "I'm not trolling, I'm curious."? I'm looking for more knowledgeable people in the Slashdot community to answer the question of the finding's significance. It's one thing to find something, and report it, but TFA gives no reason as to why this is important. Does it allow for future bases on Titan to somehow suck up methane for fuel? Is there the possibilty of methane-based life that might live in a methane lake? I'd like to know why this is important.

      • Re:What would be the significance of this? (Score:5, Insightful)

        by ProfaneBaby ( 821276 ) on Wednesday June 29, 2005 @12:45PM (#12942346)
        It's based primarily on the assumption that liquid pools are more likely to harbor the beginnings of 'some form' of life. Methane, being a carbon derivative, could perhaps provide the initial basis for simple lifeforms.

        I basically agree with you - the 'wow' factor is nice, but the true value is still pretty questionable.
        • In my experience the science section on BBC news reports on a lot of various issues without always presenting them as "wow, look at this", which this seems to be a case of. The researchers interviewed also show a bit of caution.

        • Look in the volcano (Score:5, Informative)

          by EccentricAnomaly ( 451326 ) on Wednesday June 29, 2005 @01:59PM (#12942932) Homepage
          Sunlight breaks down methane, so to have it in Titan's atmosphere (particularly at such high levels) it has to be continually replaced. You can make methane on Titan via either life or some sort of weird chemical process. So the methane is a hint at possible life.

          Titan's atmosphere is also full of a haze of complex organic molecules that continually rain down on the surface... leaving deposits of hydrocarbons on the surface hundreds of meters thick.

          Now if only these complex organics could get mixed in with water. (And it has to be water, because you need the oxygen). Guess what 'rocks' on Titan are made out of :)

          So you might have something happening in this methane lake with methane being the liquid and oxygen coming from ice... but this would be completely different from life as we know it...

          My own bet is on the volcano to look for life (The volcano on Titan erupts molten water). Also there might be life in Titan's mantle (it's made of liquid water + ammonia mixture).

          (This website: http://saturn.jpl.nasa.gov/multimedia/products/pro duct-presentations.cfm [nasa.gov] has lots of good inside information about the science results... the end of the "Titan: First Views of an Alien World" discusses where to look for life on Titan)

      • Re:What would be the significance of this? (Score:5, Interesting)

        by AnonymousJackass ( 849899 ) on Wednesday June 29, 2005 @12:50PM (#12942393)
        I think the major thing of interest here is that Titan is so different to any body in our solar system (other than Earth, of course). The fact that liquid of any kind exists is quite remarkable. It means it has been able to retain pretty much all of it's initial components, unlike most other rocky bodies that heat up and lose a lot of their original constituents. Titan is, I believe, a kind of mini proto-planet. It's similar to how Earth would've been when it was young. The difference, however, is that Earth was in a position to heat up and eveolve, whereas Titan is perpetually frozen. There's a lot of fascinating science there.

        As for methane-based life, I think it's unlikely just because of the extraordinarily low temperatures on there.
        • I think the major thing of interest here is that Titan is so different to any body in our solar system (other than Earth, of course)

          Bah! I would say that the Sun is the most unique body in this solar system.

          • Re:What would be the significance of this? (Score:4, Interesting)

            by Alex P Keaton in da ( 882660 ) on Wednesday June 29, 2005 @01:22PM (#12942638) Homepage
            From my limited astronomy background (wasn't my major, but it fascinated me so I paid attention): Through modeling, we can assume that what holds on Earth, should hold on other planets, other galaxies etc.
            I think what we are forgeting is that it seems that we know less about space than sometimes we think. For example, if memory serves me right, there is a lot of dark matter in the fringes of the galaxy- we know it is there because something is having an effect on other bodies there, however we can't detect it because it doesn't seem to emit any known energy source... (Caveat- I am not an astronomer, just a hobbyist, so take my assertion with a salt grain)
            So in my line of reasoning, it seems that this lake on Titan may not have the same characteristics as a similar lake on Earth, for a plethora of reasons that we may not understand yet.
            All that aside, how cool would it be to swim on another planet, even if in a lake of methane...
            And for those with tinfoil hats- keep in mind that some assume that we don't get real info from NASA- such as those who say that gravity on the moon is much closer to the Earth's gravity, unlike what we are told, but this can't be released because it would throw a Geurilla Wrench into the theory of relativity....
            • >>> And for those with tinfoil hats- keep in mind that some assume that we don't get real info from NASA- such as those who say that gravity on the moon is much closer to the Earth's gravity, unlike what we are told, but this can't be released because it would throw a Geurilla Wrench into the theory of relativity....

              Believe me - any aspiring scientist would LOVE to throw a Guerilla Wrench into the theory of relativity. How does a Nobel prize sounds to you?

          • the Sun is the most unique body in this solar system.
            Well, at least it was until that monolith showed up.
        • The difference, however, is that Earth was in a position to heat up and eveolve, whereas Titan is perpetually frozen.


          Until the sun starts to edge towards being a red giant... Titan will have ample opportunity to be toasty then. Admittedly, not for a period anywhere near as long as earth has enjoyed, and the surface of the sun will be much closer to Titan leading to some minor inconveniences of radiation....

        • extraordinarily low temperatures on titan? You mean like at 1-2 miles below sea level where millions of microbes live happily?

      • That is because mod's are fickle idiots. They don't agree with something so mod it troll. I get meta-mods two-three times a day...if i see yours i will meta-mod it. :)


        On the whole, I agree with you - this is not that impressive. I don't think anyone is going to say "hey lets go swim in liquid methane"...if it was water I would be more impressed. Obviously on a planet that rain's methane there would be a buildup of methane which would equate to a pool. It's like being shocked we have lakes full of wat

    • Re:What would be the significance of this? (Score:5, Informative)

      by p3d0 ( 42270 ) on Wednesday June 29, 2005 @12:48PM (#12942375)
      Surely, liquids exist in space, and surely they must pool?
      Amazingly, no. This would make Titan only the second known celestial body that currently has liquid on its surface.

      Liquids require pressure (see this [wikipedia.org]) while solids and gasses don't, and pressure is a rare thing in space.

      • What about lava?
        Doesn't Venus have lava on its surface?
        • I think the evidence points to lots of ancient volcanism, but no current activity. Venus does have lots of atmosphere and pressure, but it's probably been dry on the surface for a long time now.

        • Re:What would be the significance of this? (Score:5, Informative)

          by htrp ( 894193 ) on Wednesday June 29, 2005 @01:22PM (#12942640)
          What we mean to say is that on planets that have any kind of atmosphere, there will be some kind of fluid present. If you look at a phase diagram (crack out your old chem books), you'll realize that liquids can only exist at certain temperatures and pressures before becoming either solid or gas. As the majority of space is rather cold and the pressure is rather low, this tends to favor the formation of solids and gases.

          As for your venus question, I would venture to imagine that lava, as a higly viscous fluid would remain liquid at a relatively low pressure. The other mention is that the surface of venus is basically a massive cooking oven from all of the cloud cover of various Sulfur oxides, which would provide both sufficient temperature (from the greenhouse effect) as well as indicate a high amount of atmospheric pressure.

          What's significant about this was that it was initially hypothesized that since titan had a considerable atmosphere of methane and other hydrocarbons, that the surface of Titan was possibly covered in either a massive liquid methane ocean or a methane ice sheet. However once the Huygens probe landed, that hypothesis was disproved (the one about liquid methane on the surface).

          With what looks like a lakebed (even if it's dry) on the surface of Titan, this provides evidence that there once was/still is some liquid which eroded the landscape, which confirms that Titan's atmosphere may be more substantial than other planet's and that it may be more like earth.
          • What's significant about this was that it was initially hypothesized that since titan had a considerable atmosphere of methane and other hydrocarbons, that the surface of Titan was possibly covered in either a massive liquid methane ocean or a methane ice sheet. However once the Huygens probe landed, that hypothesis was disproved (the one about liquid methane on the surface).

            No methane ice sheet either.... Cassini's instruments (specifically VIMS I think) have shown that the surface is mostly water ice.

      • Liquids require pressure (see this) while solids and gasses don't, and pressure is a rare thing in space.

        I guess I do not understand your meaning. If anything, a solid requires more pressure than a liquid. If you have a system (held isothermal) composed of a gas and you increase the pressure, what happens? It condenses to a liquid. Continue to increase the pressure, and then what? Your liquid freezes to a solid.

        Given the context of space, I think I see your intention. That is, at extremely low temper

        • Remove pressure from the equation and you still can get solids or gas, but not liquids.

          A common molecule, CO2 (Carbon Dioxide), does not form a liquid at normal pressure (I think it takes 7 atmospheres, a google search will reveal it but I'm too lazy to bother). It is called Dry Ice when frozen, because when it melts, it directly subliminates to a gas. the point is that Dry Ice illustrates what happens to other compounds at low pressures.

      • I read the wikipedia description and I don't understand your analogy. Solids require even more pressure. Are the solid/temperature relations that create liquids which are rare?

        Don't forget that there are billions of stars just in our galaxy so saying that pressure is rare in space is a HUGE assumption.

      • Re:What would be the significance of this? (Score:5, Interesting)

        by mopomi ( 696055 ) on Wednesday June 29, 2005 @02:33PM (#12943237)
        Umm. . . No.

        Io was the second known body to have liquids on its surface (1979 Voyager flybys discovered active, extrusive volcanism). Titan was next, though we couldn't see through the clouds, so we had no idea. Triton was the fourth to possibly have liquids on its surface, though we still don't know for sure. Venus also likely has some liquid lava on its surface, though we've not seen actual volcanism. Plus, Venus probably sometimes has sulfuric acid rains, but we're not sure. Mars may also have transient liquids on its surface.

        Titan's cool because it's probably got an active hydrologic cycle (don't read hydro- to mean water, read it to mean fluid). Earth does, Venus might, Io has. . . something, Mars had one, it might still, occasionally. Triton has. . .something, and that's about it for the bodies in the solar system.

        Earth is a big body, so it still has radionuclide heat, and it's close to the sun, so it's got an abundance of energy to drive a hydrologic cycle. We can't see through Venus' clouds with more than RADAR, so we don't know what's going on there. Mars is small, so its heat has mostly left it, and it gets nearly 1/4 the energy the Earth gets from the sun, so it's cold and has little atmosphere left. Io is in a weird, slightly eccentric, orbital resonance, so its energy comes at the expense of Jupiter (and Ganymede and Europa). Titan's also in an eccentric orbit, but it doesn't have the resonance with other sats that Io has, so it "should" have lost most of its energy--one of the mysteries is why such a small body has such a huge atmosphere (and thus a hydrologic cycle). Triton might have a bit of an atmosphere, and why is also a mystery.

        So, of the many, many bodies in the solar system, there are only a few that have atmospheres, and fewer that have an active, observable hydrologic cycle. . .
    • Well, besides beings merely interesting, it's nice to see what were previously thought to be Earth-unique features on other bodies. Lakes and rivers aren't really found anywhere else, maybe at one point Mars, and maybe longer ago on Venus. To find a lake and a full water cycle, even if it's really methane, is significant because that brings our counter of objects which have lakes and rain up to 2. The more often we see simliar features and objects on other bodies, the more we can expect to find a useful com
    • "Surely, liquids exist in space"

      Actually no. Liquids cannot exist in a vacuum. Instead, some portion of the mass flashes into a vapor. This change of state reduces the temperature of the remaining mass until it freezes into a solid. So in a true vacuum (like space) matter only exists in three states, solid, gaseous, plasma. I tried to find a good link for an explanation, but this was the best I could find on short notice. If you look at the summary, you will find a line that says, "When pressure is s

      • When this vapourised mass evaporates into space in a vacuum, where does it go? Nowhere, so gravity drags it back, applying its heat back to the mass. Therefore there is no overall temperature change.

        Also you're assuming there is no heat source in the centre of the body. This would keep it at a liquid state, with a thin vapour atmosphere. Imagine if a liquid methane planet crashed into a liquid oxygen planet. And someone lit a match!
      • Phase Diagrams [google.com] is what I think you are looking for. Triple point is the term for where at a given temperature and pressure a compound is in equilibrium between solid, gas, and liquid. Lower the temperature or pressure and a liquid state becomes impossible. 4.5 torr and 0.0098C is the triple point for water.
    • Liquid is relatively uncommon on the surfaces of things in space. It's the middle ordinary state of matter, in between solids and gasses. As such, it's inherently unstable; for extreme values of pressure or temperature (low or high), you get a solid or a gas.

      It takes a peculiar set of circumstances for a liquid to persist long-term on the surface of a planet; just to start with, you need an atmosphere of high enough pressure to get above the triple point. Below that pressure, the solid phase transitions
    • Ahhh!
      So now you have stumbled upon the real reason that
      Dubya wants to "go to Mars". What better reason
      than that to invade, if not to scrounge new energy
      sources for this regime's taskmasters?

      Mere water lakes implies possible life there, and
      the likely conflict over natural resources. OTOH,
      methane breathes new life into the USA's petroleum
      industry, even if only for export to Mars. Just
      think of the transportation fees Haliburton could
      charge! New sources of energy and new markets,
      but with Uncle (Sucker) Sam

  • Fly Fishing (Score:3, Funny)

    by Shadow Wrought ( 586631 ) <shadow.wrought@g ... minus herbivore> on Wednesday June 29, 2005 @12:38PM (#12942284) Homepage Journal
    And the Space tourism boon gets another boost.
    • There are a lot of more fun things to do on a lake. Imagine wakeboarding in low gravity. The tricks and you could pull would be amazing.

  • Strewth... (Score:3, Funny)

    by gowen ( 141411 ) <gwowen@gmail.com> on Wednesday June 29, 2005 @12:40PM (#12942306) Homepage Journal
    I knew Ricki Lake had a fat ass, but I didn't know you could see it from space.

  • Not a lake (Score:4, Funny)

    by Glog ( 303500 ) on Wednesday June 29, 2005 @12:47PM (#12942369)
    The announcement was later rectracted by NASA officials after it was confirmed that the "dried-up lake" was, in fact, Joan Rivers vacationing in the new Klingon botox retreat.

  • Got a match? (Score:5, Funny)

    by tzuriel ( 855916 ) on Wednesday June 29, 2005 @12:50PM (#12942399)
    In other news, Titan went up in flames earlier this morning when a careless tourist ignored the "No Smoking" signs clearly posted in the vicinity of "Methane Lake". When will these off-worlders learn to pay attention?

  • It could also be.. (Score:3, Insightful)

    by erikkemperman ( 252014 ) on Wednesday June 29, 2005 @12:51PM (#12942409)
    But don't get too excited yet [...] it could also be a dried up lake that left dark deposits.

    IANA rocket scientist but.. Would we not be excited if it turned out to be a lake -- dried up or otherwise? I mean, are dried-up lakes often found out there, relative to not-yet-dried-up ones? Just curious.
    • If it isn't dried up, we could try to land near it and do research on the liquid. We might learn more than just looking at a dried up lake. There might even be organisms of some sort in the methane.

      Being a lake of methane does create unique problems I guess. It might be hard to do things around it with electrical equipment without blowing up the entire lake. I wonder if methane can blow up in a place without oxygen.
      • If it isn't dried up, we could try to land near it and do research on the liquid.

        Not to belabour the point, but likewise I would imagine we could land near (or even in) a dried up lake and do research on the deposits?

        I guess my original question was: why would the dried-up-ness matter so much? TFA is sort of neutral but the summary suggests that it would be a big disappointment if it were dried up. Presumably this is because of a belief that some fluids are prerequisite to life, but where exactly does t
  • ...clearly visible and 235km across that looks like a like. Previosuly a probe landed on Titan photographing lakelike features all the way down. And the only way people can be sure it is a lake is by viewing the feature from the right angle to see if it glints in the sun. 235km across! I don't know about you, but if that's the best they can do, I think they loaded up Cassini and Huygens with the wrong set of instruments.
    • Actually, I think it's an elegantly simple solution to a complex problem. To detect "lakes" by other means would likely require a device that performs many varied tasks consistantly and have the ability to survive a space trip. Also, it would most likely be a highly dedicated piece of equipment taking up valuable space. Not to mention, how do you detect if something is liquid from orbit??? If you have an easy answer, I'm sure NASA would LOVE to hear it. Also, they were going to have cameras anyway for
      • I think it's pretty obviuos that they chose the right equipment.
        Because it's obvious that something that could detect liquid would have absolutely no other uses whatsoever. Right.

        If you have an easy answer, I'm sure NASA would LOVE to hear it
        Various forms of radar. It works. I don't need to tell NASA or JPL about it.
    • Finding lakes was not a part of the mission plan... it was a chance discovery. They can't possibly load it up with every instrument they might ever conceivably need.
      • It's not a chance discovery. In fact, Huygens was designed to land on either a liquid or solid surface.
        • That's because until Cassini got there, they had no idea what the surface was like because of thick clouds. If Huygens had landed in the lake, it would have been blazingly obvious whether it's liquid or solid. Trying to determine that from orbit is an entirely different matter.

          So maybe I was wrong in that finding *liquid* was not something they hadn't fully expected, but Cassini was never designed to determine whether any part of the surface was liquid or solid.
          • Cassini was never designed to determine whether any part of the surface was liquid or solid.
            Yes, that's my point. I wish it had been designed that way. It's also a task well within NASA's ability.
            • You're forgetting that when you're sending a probe to a distant planet, every kg costs millions of dollars, every instrument consumes power, every bit of complexity increases the chance of failure.

    • The wrong set of instruments (Score:2, Insightful)

      by Anonymous Coward
      I think they loaded up Cassini and Huygens with the wrong set of instruments.

      The instruments on Cassini and Huygens are revealing Titan as place worthy of much further exploration. I thought the reveal of a river bed like structure on an ice moon was worth the price of admission alone. Total success in my book, if nothing more these missions define what we might want to send in subsequent probes.
    • The point is they *can* tell if it's a lake. If the sun-glinting method works, sure it might seem a bit goofy, but it frees up mass to use with other instruments.

  • Any sign of any... (Score:3, Funny)

    by centauri ( 217890 ) on Wednesday June 29, 2005 @01:11PM (#12942568) Homepage
    Sirens?

  • Interesting thought to ponder and discuss. (Score:3, Interesting)

    by Heem ( 448667 ) on Wednesday June 29, 2005 @02:02PM (#12942957) Homepage Journal
    So we are sending all these probes.. Mars and Titan for example.

    What if one of them returned images of cities, or villages, either deserted or actively inhabited. - What do you think would happen? Would there be a giant cover up? Or maybe a giant newsflash? Would those responsible for the probe just publically "forget" that they ever sent a probe there?

    • Its off topic bro...

      Choose your favorite fan fiction:
      - War of the Worlds
      - Mars Attacks
      - Contact
      - Red Planet ...

      By the by, the Seti project has discovered not one but a handful of interesting candidate signals. The results of this, and reobservation of one of the most interesting signals, was for the Seti group to totally downplay the news. As such, not many people know about it.

      I suspect the same thing for any find - a brief news bite that is downplayed by the experts and ordinary people focus on what
  • So, is Titan an Inter Galactic Filling Station for Vogon space ships, or does it lack something - an oxidizer maybe?

    Could you fill up on Titan with methane fuel and on Saturn with oxigen?
  • Huygens> Affirmative, parachute deployed.

    Cassini> Can you see anything down there yet?

    Huygens> Not really, it's pretty dark.

    Cassini> Turn on your flashlight.

    Huygens> Alright, taking it out... aw crap, I dropped it, not gettin that one back, I'm still at 10,000 meters.

    Cassini> Oh that sucks, what about your water proof matches? Says here in the manual that we should use them in case of emergency.

    Huygens> Well, it's better than sitting here in the dark... Taking them out, opening th
  • ...how would it behave? Is liquid methane more viscous than water or less? What kind of splash/waves would you get compared to a regular water lake if, for example, you threw a rock into a liquid methane lake? Does Titan have tides, and if so, would they be strong enough to create the lake shore lapping effect we see with lakes here? Titan's gravity is a lot lower than Earth's, of course, so that would affect the methane's behavior, too... what would the differences be between the behavior of a methane

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