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Titan's Tropical Weather

Posted by kdawson on Tue Oct 02, 2007 07:10 PM
from the get-a-tan-from-standing-in-the-methane-rain dept.
Space Science
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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Submission: Weather on Titan Is Tropical in Nature by pcol (577822)
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  • 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) Homepage 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.

    • 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.

        • 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.
    • Because usually the methane instead of oxygen in the atmosphere is usually the first indication that it probably doesn't qualify.
    • 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.

        • 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.
      • 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...

  • 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.

  • "Life"? (Score:4, Informative)

    by headkase (533448) <pickett.bill@gmail.com> 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.

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

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

      • 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.
          • 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?
          • Aren't the laws of physics the same everywhere? Life is optimized for the physics we have.
  • ...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.
  • 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. :-)

    • Re:Yeah but... (Score:5, Informative)

      by volcanopele (537152) on Tuesday October 02 2007, @07:15PM (#20831437)
      Har har, but no, it wouldn't. Methane is odorless. That's why gas companies have to include additives with natural gas, so leaks can be detected.

    • Re: (Score:3, Informative)

      by renehollan (138013)
      No.

      Methane, while produced in the gut of most animals, is odorless. The smell of flatus, to which you seam to be alluding, is mostly due to sulfur-containing compounds: Hydrogen Sulfide (in the case of the notorious "egg farts"), and various mercaptans, IIRC.

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