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Space Science

Titan's Tropical Weather 102

Posted by kdawson from the get-a-tan-from-standing-in-the-methane-rain dept.
Hugh Pickens writes "Climate researchers Ray Pierrehumbert and Jonathan Mitchell at the University of Chicago say that Titan, the only moon in the solar system large enough to support an atmosphere, has many of the same weather features as Earth, but with completely different substances that work at temperatures that plunge down to minus 170 degrees Celsius. Pierrehumbert and Mitchell call Titan's climate 'tropical,' a climate that is warm to hot and wet year-round, because on Titan methane assumes the role of water and exists in enough abundance to condense into rain and form puddles on the surface. Titan's tropical nature means that scientists can observe the behavior of its clouds using theories they've developed to understand Earth's tropics. For example, Titan's atmosphere produces an updraft where surface winds converge to lift evaporated methane up to cooler temperatures and lower pressures, where much of it condenses and forms clouds, 'a well-known feature on Earth called an ITCZ, the inter-tropical convergence zone,' Mitchell says."
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Titan's Tropical Weather More

Titan's Tropical Weather

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  • Does Titan Really Exist? (Score:1, Funny)

    by Anonymous Coward
    I think we should be wary of these so-called "scientists" who do nothing but tell us lies about so-called global warming, denying the truth [shelleytherepublican.com]. They are usually atheists, which explains why they believe in the absurd theory of heliocentricism [wordpress.com]. Instead of curing us with prayer, doctors kill our precious children by refusing to prescribe antibiotics [shelleytherepublican.com]. Furthermore, scietists are notorious for using shoddy un-Christian European software like Linux [shelleytherepublican.com], thereby destroying our Great Nation's wealth maximization potential

    • Re: (Score:3, Insightful)

      by Dunbal ( 464142 )
      Instead of curing us with prayer, doctors kill our precious children by refusing to prescribe antibiotics.

      Speaking as a doctor I would appreciate if you could provide proof of this claim (other than the ramblings of a lunatic). Considering the continuing increased life expectancy of humans in the developed world, and the decreased infant mortality rates prevalent over the past and this century, I'd say that medical science has a fair grasp of what it's doing. Although it's hard to pair

      • Re: (Score:2, Funny)

        by iminplaya ( 723125 )
        Speaking as a doctor...

        Ehh, what's up, doc?
      • Wow the joke went right over your head

      • Re: (Score:2)

        by Baikala ( 564096 )
        Joke:   ->
        You:     O
                /|\
                / \

      • Re: (Score:2)

        by rk ( 6314 )

        A doctor, eh? It looks as though you performed a senseofhumorectomy on yourself, hoss. I think it's plainly obvious the GP was a lampoon of an anti-science fundamentalist. I mean seriously... against heliocentrism? Even the most hidebound reactionary Bible literalists conceded that one 200 years ago.

    • Thanks for the links to STR. I laughed my tail off! I've never heard of it before. It looks like a marvelously crafted satire, but it is so perfectly crafted that they never wink at you to let you know they are just kidding. Do you know if it is for real? It can't be real - nobody really is this far out, at least not anyone who can form a cohesive sentence.
    • Yay, a pseudo-right-wing nut-job. I could go into full unadulterated detail about how little the quoted sources make sense from even a logical standpoint, but then it would be pretty long and totally defeat the purpose of this post. Too bad the "doctor" that posted to this thread has no sense of humor to work with. I would mod this poster Sarcasm +2, but I have no points to work with.
      • Seriously, that was total flame-bait... There is NO WAY someone is that stupid. Astronomy, discredited? Ever look up? You guys don't need to take anything in that post as meaningful... either someone was trying to be funny, or trying get flamed.
  • I'd say the biggest factor in determining if it's habitable is going to be its orbit and period, because if it's way off from our 24-hour day or 365~ day year, people would have a harder time adjusting than if it were simply lower gravity or hot or cold.

    I found it very interesting that Mars has a 24-hour day, and saw that as the biggest sign that we'll be inhabiting it someday soon, probably within our lifetime.

    • Re:The biggest factor (Score:4, Interesting)

      by Tablizer ( 95088 ) on Tuesday October 02, 2007 @07:26PM (#20831547) Journal
      I'd say the biggest factor in determining if it's habitable is going to be its orbit and period, because if it's way off from our 24-hour day or 365~ day year, people would have a harder time adjusting than if it were simply lower gravity or hot or cold.

      Titan does not really have "days" because its thick atmosphere spreads the warmth fairly equally to the day and night side. Besides, Titan is too cold for Humans. It is interesting in that it is doing on the methane level what Earth does on the water level. It's like a parallel universe where the water is instead methane. However, we humans are not compatible with that one. The "problem" is roughly comparable to an antimatter universe working like the matter universe (weather, rocks, etc.), but an antimatter being can't just move to the matter version as is.
         

      • Re:The biggest factor (Score:5, Interesting)

        by Jeff DeMaagd ( 2015 ) on Tuesday October 02, 2007 @07:38PM (#20831661) Homepage Journal
        I think the GP concern of "days" is the length of when you have light, not temperature. I don't think it's that much of a concern though because there would be so much less light anyway. I think the "nights" where Titan is closer to the Sun might even be brighter than "days" because you get the diffuse reflection of sunlight off of Saturn. The times where the moon is behind Saturn are going to be extremely dark though.
        • If day is light directly from the sun, and night is light from the sun reflected off of Saturn... how can the night possibly be brighter than the day? Light loses intensity as it reflects.
          • Every part of Saturn exposed to the sun is reflecting part of its light back toward the 'dark' side of Titan in transit. If Saturn is sufficiently large and sufficiently reflective, the 'dark' side of Titan could be brighter. I don't know if it is though.
      • From Hartmann's Moons and Planets: Titan goes around Saturn in 15.94 days, and it is tidally locked with one side always facing Saturn. On the Saturn facing side, there would sunlight for 8 days followed by Saturn's reflected light for 8 days, The days where there are sunlight, Titan would be on Saturn's dark side, and when the Saturn facing side of Titan is not facing the sun, it sees Saturn's reflected light from the Sun. However, there might be times when this side of Titan faces the Sun and Saturn eclip

        • Re: (Score:1)

          by Tablizer ( 95088 )
          I've read that Titan is so dim that any astronauts doing any serious work the surface would need spotlights anyhow. The Huygens (sp?) lander even had a landing light. The sun (thru the haze) merely adds a twilight-like ambience.
                 

    • Re:The biggest factor (Score:5, Insightful)

      by RuBLed ( 995686 ) on Tuesday October 02, 2007 @07:36PM (#20831643)

      I'd say the biggest factor in determining if it's habitable is going to be its orbit and period, because if it's way off from our 24-hour day or 365~ day year, people would have a harder time adjusting than if it were simply lower gravity or hot or cold.


      Fortunately for most of us, the clock on our desktops are the only way we're keeping track of time. (It's always dark in the basement you know)

      IMHO, Planetary time (or moon time, etc) is the least of our concerns when considering a habitable planet.
      • But by the time we as a species reach Titan and consider colonizing it, we'll have the technology to overcome any environmental hazards posed by its strange ecosystem.

        It'll still be difficult to get over the "Jet lag" (probably need a better term for that) so I still predict that it'll be a bigger influence on whether people live there or not.

      • Re:The biggest factor (Score:5, Insightful)

        by ColdWetDog ( 752185 ) on Tuesday October 02, 2007 @09:14PM (#20832361) Homepage
        Something about that comment being modded "insightful" vs "funny" scares me.

        • Re: (Score:2)

          by rxmd ( 205533 )

          Something about that comment being modded "insightful" vs "funny" scares me.

          I think that's what we have to put up with as long as there is no "+1, Grim Reality" moderation option.

      • Re: (Score:1)

        by ls671 ( 1122017 )
        Agreed, I find that people sensible to daylight / darkness are closer to cattle than to sophisticated intelligent beings able to travel in space ;-)

      • Re: (Score:2)

        by GreggBz ( 777373 )
        Stephen Baxter rocks! I loved his novel Voyage. This one, unfortunately is mediocre, but still some of the best hard SciFi today.
        • Stephen Baxter rocks! ... This one, unfortunately is mediocre

          James Nicoll [wikiquote.org] said it better than I ever could:

          [F]olks would better off dipping their heads in a bucket of liquid [nitrogen] and battering them against a tree very very hard than reading Baxter's Titan. It would not surprise me if reading that book causes birth defects.

    • Re: (Score:2)

      by jmauro ( 32523 )
      Because usually the methane instead of oxygen in the atmosphere is usually the first indication that it probably doesn't qualify.
      • All that methane, and it's still cold?

        But I thought methane was a worse greenhouse gas than carbon monoxide?

        Just goes to show we should be sceptical about this climate change hullabaloo, no?

        :P

    • To be halfway habitable on permanent basis it needs good internat infrasturcture. Alternatively if it is going to be a tropoical vacation paradise it better have coconuts.

      Can you get there on frequent flier miles?

    • Re:The biggest factor (Score:5, Interesting)

      by localman ( 111171 ) on Tuesday October 02, 2007 @08:31PM (#20832017) Homepage
      I'd have to disagree -- people live in different areas of the earth where days are of vastly different lengths. And while it's not super healthy, many people live on all manner of strange day cycles with artificial light. I have read that without any clues as to time, people don't naturally settle into a 24 hour day anyways, and that in fact they vary their sleeping cycles longer and shorter over time.

      On the other hand, low gravity wreaks havoc with bones and blood vessel walls and such. Hot and cold we can control pretty well, so that's not a huge concern, though it certainly makes it more expensive. Radiation and such may also be a concern for planets without a strong magnetic field. And then there's the whole sustainable artificial ecosystem thing we've yet to work out to any real degree :)

      Overall I think living on another planet is going to be a lot harder than we generally expect. We take for granted how well adapted we are to the specifics of planet Earth, and how much we depend on millions of other things that are also well adapted for the specifics of planet Earth. As someone suggested: it would be much easier to build a colony on the bottom of Earth's ocean than another planet, but we haven't even done that yet because it's cost prohibitive and the benefits aren't clear.

      But we'll get there someday, I suppose!

      Cheers.

      • people live in different areas of the earth where days are of vastly different lengths.
        It's still 24 hours between sunsets though.
        • Not in polar regions. Thanks to the polar night and the midnight sun, they may not even have proper sunsets or sunrises for over a day!

          Besides, as localman mentioned, our natural circadian rhythm without zeitgebers (things that let you know what time it is, like the sun) isn't really 24 hours. I've heard everything between 25 and 30 hours as the natural length.

        • Re:The biggest factor (Score:4, Insightful)

          by 15Bit ( 940730 ) on Wednesday October 03, 2007 @05:04AM (#20834799)
          > It's still 24 hours between sunsets though.

          No its not. In all places except the equator the length of sunlight changes slightly every day. The arctic and antarctic circles describe the latitudes at which the sun actually doesn't set one day per year.

          If you go north of the arctic circle (or south of the antarctic circle) the effect gets greater and greater. This doesn't make them uninhabitable areas but it does mean that you can have weeks without a sunset (or a sunrise in the winter). A good example is Tromsø in north Norway. Its a fairly significant place, with a population of 60,000+ and a university. Yet they get a month of sunshine (and the same of darkness) every year - see http://www.gaisma.com/en/location/tromso.html [gaisma.com]. And Tromsø isn't even all that far north.

          Hell, even where i am (a couple of hundred km short of the arctic circle) it doesn't really get dark during the summer. The sun "sets", but it only just dips below the horizon and so the twilight is extremely bright. Indeed, it can be brighter at 1am on a clear night than at midday with heavy clouds.

    • I would be willing to live in another planet as a hermit and occassionaly contact Earth via InterPlaNet [ipnsig.org] to learn news and buy food that I couldn't grow myself or shiny laptops that I couldn't manufacture alone (what else would I do in space if I couldn't play with GNU/Linux?). Believe me, the lack of a 24-hour day would be the least important of my difficulties. The major difficulty is the lack of the tri-billions of euros that I would need to escape from the Earth's gravity, transporting my hermit colony

    • if it's way off from our 24-hour day or 365~ day year, people would have a harder time adjusting than if it were simply lower gravity or hot or cold.

      I agree. And if someone reverses Venus's spin, accelerates it to a 24 hour day and speeds its orbit around the sun, hey, I'm packing my shorts and moving there!

    • I don't know about that. There are jobs right now where people regularly work very weird hours that are always changing and manage well enough. Monday, I got off work and went to sleep at the time I got to work today and I work 8 hour+ days. It takes some adjustment and dosn't work any miracles for your social life, but you get used to it. I think the length of the year would have even less of an effect than the length of the day.
    • I'd say the biggest factor in determining habitability is that Titan's atmosphere is highly toxic to humans (contains Hydrogen Cyanide). If any of that atmosphere gets into a habitat or environment suit, it can be fatal.

  • All Inclusive Tropical Vacations (Score:4, Interesting)

    by Jennifer York ( 1021509 ) on Tuesday October 02, 2007 @07:18PM (#20831469) Homepage
    How long before we have Virgin Galactic [virgingalactic.com] all inclusive vacation plans for this appealing "Tropical" destination?

    • Not long, but good luck getting through spaceport security when methane is a liquid.

      • Re: (Score:2)

        by Dunbal ( 464142 )
        but good luck getting through spaceport security when methane is a liquid.

              Fortunately the security people will also be completely solid at those temperatures, so getting through security should be a breeze...
    • Forget vacations. We need to send some tankers to Titan and bring back some methane to earth! Let the exploitation begin!

      • Re:All Inclusive Tropical Vacations (Score:5, Insightful)

        by Jeff DeMaagd ( 2015 ) on Tuesday October 02, 2007 @08:56PM (#20832219) Homepage Journal
        I realize it's probably a joke, but we've got frozen methane hydrate, underwater, here on Earth. There was one quote that said that if the moon had gold bricks for the taking it would still be a major loss to collect them. At Titan? Forget it.
        • Hell, if there were gold bricks for the taking on the moon, you better believe that we'd find a way to get them cheaply! Nothing spurs innovation better than good old fashioned greed. Well...nothing besides neccessity and war that is.
          • Unlikely. There are cheaper ways to get there, but it takes energy. Energy is not free. The amount of energy it takes to loft a craft to escape velocity is staggering, and the cost of buying that energy isn't going down.

          • Nothing spurs innovation better than good old fashioned greed. Well...nothing besides neccessity and war that is.

            Funny how often those two overlap...

        • if the moon had gold bricks for the taking
          Latinum is where the money is! Silly humans...
        • Best to leave the methane hydrate where it is, and for $_deity's sake don't burn it. . .

          http://en.wikipedia.org/wiki/Methane_burp [wikipedia.org]

  • Equatorial Deserts (Score:4, Interesting)

    by volcanopele ( 537152 ) on Tuesday October 02, 2007 @07:23PM (#20831511)
    It is nice to see a climate model that adds in the information we have gleaned from the equatorial deserts on Titan. Much of the equatorial dark terrain on Titan is covered in sand dunes (made of organics, rather than quartz sand) while the bright material near the equator looks very much like the desert US southwest, with large mesas carved by the action of flowing methane, suggestive of short-duration, but high-volume, rain showers at equatorial latitudes. Much of the climate studies done recently have focused on the weather at the poles, were the majority of large clouds systems, lakes, and seas have been observed.
    • made of organics, rather than quartz sand

      Since they are on Titan, isn't it a bit of a misnomer to refer to them as organics?

      It makes me wonder how much of the Methane (or other organic compounds) on Earth were abiogenically created.

  • Ganymede is larger (Score:1, Informative)

    by Anonymous Coward
    and also has an atmosphere.
    • Well, I wouldn't exactly call what Ganymede has an atmosphere... but that is a valid point, other moons do have atmosphere, particularly Io and Triton. I guess the submitter meant to say "the only moon with a substantial atmosphere".

    • Re: (Score:1)

      by mjwx ( 966435 )

      also has an atmosphere
      Yeah but the nightlife is on Europa.

  • "Life"? (Score:4, Informative)

    by headkase ( 533448 ) on Tuesday October 02, 2007 @07:48PM (#20831713)
    Starting with the definition of Life as a process, I wonder if on Titan are the chemicals that exist there capable of encoding information such as the chemicals in DNA here on Earth? Life as we know it works with water and carbon as it's base substrates but these are not the only substrates a process that encodes structures that reproduce is limited to.
    • Life as we know it works with water and carbon as it's base substrates but these are not the only substrates a process that encodes structures that reproduce is limited to.

      I'm not a biochemist, but life does not depend only on water and carbon. IIRC, the most abundant elements in living matter are the "CHONPS" group: carbon, hydrogen, oxygen, nitrogen, phosphor, and sulfur. Although living cells are *mostly* carbon, hydrogen, and oxygen, several other elements are indispensable to life.

      I'm rather skeptic

      • Re:It depends on other elements (Score:5, Interesting)

        by wikinerd ( 809585 ) on Tuesday October 02, 2007 @08:43PM (#20832117) Journal

        lower temperature means less energy, which means less chemical reactions happening. Less reactions means less probability of hitting on the right combination needed to get a self-reproducing molecule.

        Many cold worlds exhibit cryovolcanism. Some cold moons are also experiencing tidal forces. Some worlds may have underground oceans. Sun is not the only source of energy out there. There is kinetic energy as well, and cryovolcanism, tidalism, oceans, and geoactivity may provide it in abundance.

        It looks like self-reproducing molecules on Earth have been successful in utilising every form of energy they could find, even in harsh underground environments. With such a determination to live and reproduce, I think that some molecules on a cold world could utilise kinetic energy to sustain their reproduction.

        • Re: (Score:2)

          by Dunbal ( 464142 )
          Sun is not the only source of energy out there.

                Can't wait to see the earthquake-harvesting bacteria thriving off the aftershocks !

          • Sun is not the only source of energy out there.

            Can't wait to see the earthquake-harvesting bacteria thriving off the aftershocks !
            Well try not to forget Jupiter emits more energy than it receives from the Sun. If there were a place in our solar system to look for life, a moon of Jupiter is an awesome starting-point.

      • Re:It depends on other elements (Score:5, Interesting)

        by Dunbal ( 464142 ) on Tuesday October 02, 2007 @09:30PM (#20832475)
        Although living cells are *mostly* carbon, hydrogen, and oxygen, several other elements are indispensable to life.

              And you won't get very far without iron and/or some other transition element that you can use to push electrons around to catalyze reactions. I'm not thinking hemoglobin but rather oxidative phosphorylation/electron transport chains or some xenobiochemical equivalent.

              The other problem is that life on earth thrives because we are able to create a "barrier" between the polar world around us by using phospholipids. That way we can divide the world into "the water outside the cell" and "the water inside the cell", and then control the "inside" to our liking.

              In a methane world, where your solvent will presumably be some organic substance, instead of water: what do you use as an relatively impermeable barrier? Personally I'd love to see organisms with crystalline cell walls, however I imagine growth and reproduction would be a bitch.

        • Re: (Score:1)

          by urIkon ( 1073202 )
          Or may take some other form we are, from our completely subjective earthen perspective, are incapable and even naive to assume that life is bound to the same fundamental structures we are.
          • I've always thought it lame to always look for life similar to Earth, when unless the planet is like Earth, there couldn't be such life there.

            It seems like we haven't exhausted the possibilities on this planet: What says that life forms based on convection currents of molten iron cannot exist in Earth's core?

          • Re: (Score:2)

            by MenTaLguY ( 5483 )
            Aren't the laws of physics the same everywhere? Life is optimized for the physics we have.

        • Re: (Score:1)

          by Tablizer ( 95088 )
          Personally I'd love to see organisms with crystalline cell walls, however I imagine growth and reproduction would be a bitch.

          Perhaps they would use something similar to what snails use: rather than moult a shell, you expand in a cone or spiral, leaving the original in place; but on a smaller scale. You just need some way to plug up the door.
                       

        • Re: (Score:2)

          by shawb ( 16347 )
          It isn't that difficult to imagine a chemical could create a similar barrier in a world based on an organic solvent. Essentially, all that is needed is a compound that is polar along the majority of the length and non-polar at one or both ends. Replacing the phosphorous that caps a phospholipid with a more ionic chemical may even be enough to do the trick, as the neighboring carbons on the chain would donate a partial charge, reducing their solubility in an organic solvent. If that would fail, replacing
  • ...then Roy Batty's last line would have been, "Like... tears in the methane."
  • If only it were a *dry* heat!
  • If titan is so full of organic compounds, would it have valuable resources we could mine, that aren't abundant on earth and might actually make it cost effective?
  • Cool - Minus 170 really is quite tropical - almost like Winnipeg in summer. I wonder whether Titan has mosquitoes too.

    • Re: (Score:3, Interesting)

      by MichaelSmith ( 789609 )

      Like Winnipeg in summer

      Well its about twice as cold as the coldest place on Earth. But thats better as being twice as hot. Cold is much easier to engineer around.

      With all that Methane in the atmosphere I wonder if you could get a modern vehicle using an internal combustion engine to work on the surface of Titan. Just put liquid oxygen in the fuel tank and feed it in through the fuel injection system.

      • Hmm, LOX in the tank would be an interesting reversal.

        Basically, there is no shortage of rocket fuel in the solar system. The trouble is the lack of oxidizer. So any traveller to the our planets need not take fuel with, just siphon some off any of the gas giants, but without LOX, the rocket won`t get far.
  • Now that sounds like rain that is finally not going to ruin your camp fire grill party. It's more like "duck and cover, rain is about to hit the fire".
  • that are supposed to live there. I heard there are some really nice ones there. Thats what that guy with that kazak dog told me anyway......
  • The first explorers are advised to bring pith helmets and machetes. Personally, I find a brolly quite useful too.
  • So, are there any indications that Titan is experiencing the same global warming effects we are? Or, do we need to send an SUV there to heat things up?

  • Sorry, but I'm going to Nitpick (Score:3, Informative)

    by CheshireCatCO ( 185193 ) on Wednesday October 03, 2007 @09:48AM (#20837205) Homepage

    Titan, the only moon in the solar system large enough to support an atmosphere
    Sorry to nitpick, but this just isn't true. I can think of at least two other moons that have atmospheres (Io at Jupiter and Triton at Neptune), Titan's is just the thickest and most Earth-like. It can be argued (and is, but some researchers) that even the Moon has an atmosphere, it's just very thin and made of silicates and sodium.

    In any case, not only is Titan not alone, it's not the "only moon large enough..." Ganymede at Jupiter is actually larger than Titan, both in radius and (especially) in mass. If it were only a matter of size, Ganymede would have a thicker atmosphere than Titan. Heck, Titan's surface pressure is 1.5 times that of Earth, so clearly size isn't the only issue.

    Sorry for the interruption, please carry on. :-)

  • call Titan's climate 'tropical,' a climate that is warm to hot and wet year-round, because on Titan methane assumes the role of water and exists in enough abundance to condense into rain and form puddles on the surface.

    Titan must have a severe moon warming problem, since methane is one of the worst of the greenhouse gases. 8X worse than plain CO2.

    • Stop trolling.

      Waters is also a "greenhouse gas". It is not a problem because it is always saturated anyway, like methane on Titan. The problem is always increase of greenhouse gas *concentration* in atmosphere. That's where CO2 on earth and human activity come in.

  • It's the humidity that'll kill you. I'll be here all week.
  • I think i'm loosing it here on Slashdot This information is not much more then a copy of some science news on many bulletins a few days ago. Well that's not to bad, one might miss some topics and find them back here in slashdot But then slashdot is a discussion board, so the collective brain of all nerds here on earth. At least I would think someone posting an article here putting an opinion, or some thoughts about it here too. So the collective can get amused with some thinking. Well there is no opinion

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