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Space Science

Titan Occupies A Solar System Sweet Spot 243

Posted by Zonk
from the i-had-dibs dept.
SocietyoftheFist writes "From an article on the BBC website, scientists have determined that Titan occupies a 'sweet spot' much like Earth. Venus is the same size as Earth but too hot so water boiled off long ago ending most geologic processes. Mars is too small to generate enough heat to keep water from freezing so it too slowed down geologically. Titan is much like the Earth with winds, rains and tectonic forces but instead of water it has an abundance of methane. Methane is liquid at the temperatures found in Titan's atmosphere and replaces water in the equation."
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Titan Occupies A Solar System Sweet Spot

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  • by Saven Marek (739395) on Saturday September 10, 2005 @06:34PM (#13528564)
    Methane hey. that could be spelled "oil"

    I say we go get rid of the terrorist on Titan.
    • Actually gasoline is typically octane.. not methane.
      While crude oil does contain some methane, that is not the primary component, nor the one we use for diesel or common car gas.

      Methane is very flammable.. you'd have to keep the gas compressed all the time.. seems like an awful lot of trouble.

      The political motivations of your post however, are quite clear... Go post on fark if you want to start a flame war.
      • "Actually gasoline is typically octane.. not methane."

        True, the major components of gasoline are Octane and he[iane. Of course thare are many other additives including ethano;.

        "Methane is very flammable.. you'd have to keep the gas compressed all the time.."

        You'd have to keep it compressed because it is a gas at room temperature, so it would take up a lot of space. Of course you could keep it in a gas bag on the roof of the vehicle like people did in WWII with coal gas.

        Methane is the major component of 'n
    • Re:Hmm, methane (Score:2, Interesting)

      Hey, don't laugh it off so quickly. Conspiracy theorists might want to consult Stephen Baxter's Titan [amazon.com], in which the accidental destruction of the spaceshuttle Columbia on re-entry prompts a daring mission to Titan, to prep it for human colonization / mining (and it doesn't hurt that it comes at a time when NASA's funding is being reconsidered, and the program itself re-evaluated -- yup, still talking about the book).

      Published November 1, 1998.

      I remember hearing about the "Columbia Disaster" and thinking

  • by DrEldarion (114072) on Saturday September 10, 2005 @06:37PM (#13528578)
    Methane? Ah ha, I've got it!

    Cows are really aliens from Titan sent to observe us. The methane they, uh, "give off" is just a little air leak in their otherwise-perfect disguises.
    • by jd (1658)
      Well, you have noticed the similarity between the "Men in Black" and restaurant waiters, haven't you? And you've noticed they delight in serving steaks? Well, that's what happens when the Titan aliens they've interrogated in Area 51 are finished with.
    • ...your real name is Gary Larson? [blogger.com]
  • by VoidWraith (797276) <void_wraith.hotmail@com> on Saturday September 10, 2005 @06:44PM (#13528623)
    In both of their "sweet spot" scenarios, they attribute boiling water to solar proximity, but then frozen water to planetary mass. In both cases, the whole thing can be explained just with solar proximity, as it usually has been. Planets farther away have colder temperatures. Yes, its true that a smaller planet will retain less heat, but the primary factor here is still solar proximity.
    • "Yes, its true that a smaller planet will retain less heat,"

      We don't just retain heat, we generate heat. Otherwise the earth's core would have solidified a long time ago, and we'd be very irradiated.

      If a smaller planet were in earth's orbit, it might not generate enough heat on its own to thaw out of an ice age.
      • We don't just retain heat, we generate heat. Otherwise the earth's core would have solidified a long time ago, and we'd be very irradiated.

        Can you explain how the heat is generated? I always assumed that the Earth's core (and mantle) are hot because it takes a really long time for all that molten rock to cool off. All the rocks that collided together 4.5 billion years ago to form the Earth generated (past tense) a lot of heat from collisions, but there's no internal heat generator.

        So correct me.

        • I believe you are mostly correct. There is obviously a substantial amount of heat generated by fission, but it isn't why the Earth is still hot. Also, I don't know if anyone has ever linked the latent heat of Earth to pulling us out of an ice age which is a purely atmospheric phenomenon. It is more closely linked to water and CO2 cycling I believe.
        • " but there's no internal heat generator."

          First, there's friction between the layers of gooey nougat inside the earth as they move at different velocities with respect to each other. Secondly, friction from the tectonic plates moving on top of that gooey nougat (the continents, by providing thicker insulation in parts, also assure temperature differentials in the gooey nougat, causing yet more motion). Third, tidal forces from the moon and the sun that stir the gooey nougat up as they move around (bringin
        • Lord Kelvin estimated the age of the Earth at about 20-40 million years, based on the science (thermodynamics) of his day, and how long it should have taken for the Earth to cool to its current state. He didn't, and couldn't have, taken into account decay heat from radioactive elements.

          See Lord Kelvin and the Age of the Earth [rochester.edu] (PDF).

          • Not to mention newer suggestions that there's a number of slow-burning fission reactions going on at the earth's core.

            However, the truth is that the inside of the planet is hollow, and populated. There's a star at the center. There's even a small moon! It's a neat place.

    • The boiling point of a liquid is determined both by its temperature and the atmospheric pressure. Mars has a thinner atmosphere because it can't hold as much gas. Oxygen on Mars is too light and escapes off the face of the planet, just as Helium and free Hydrogen do on Earth.
    • The article is inaccurate.

      Solar proximity is only one of the determining factors for hospitable planets.

      For example, take Earth and put it in Mars orbit. You don't get a frozen barren planet. You get a cooler planet for sure, but one that would still harbor life quite comfortably.

      Put Earth in Venus's orbit, and you get a waremer world for sure, but one that could still harbor life.

      Earth isn't Earth just because of where it's located. Our gravity allows for our planet to maintain an atmosphere. We have enoug
  • Speed (Score:5, Interesting)

    by JohnWiney (656829) on Saturday September 10, 2005 @06:45PM (#13528628)
    A fundamental issue, as I understamd it, is the speed of chemical reactions. Roughly speaking, chemical process speeds are related exponentially to temperature. Generally speaking, the temperatures on Titan are far to low to permit life processes anything like the sort we see on Earth. That isn't a definite "no", but any life forms would have to be radically different from anything on Earth.
    • Re:Speed (Score:5, Interesting)

      by RobertF (892444) on Saturday September 10, 2005 @06:57PM (#13528686) Homepage
      Most likely, if there's any life it's by heat vents. They said Titan is geologically active, and appears to be erupting continuously. In that case, it's similar to life that exists in vents in the crust under the ocean. Those things do look other worldly, but I'd wager that its conceivable that a single-cell organism could develop by these geological hotspots.
    • Re:Speed (Score:3, Informative)

      by frgough (890240)
      Chemical reactions for life go too slowly at our temperature, too, and thank goodness they do or we would all chemically react ourselves into a pile of goo in a matter of a few minutes.

      You want reactions that are slow, but that can be sped up using a catalyst when necessary. That allows you to control the reactions and switch them on and off as needed. In biological systems enzymes are the catalysts.
    • Roughly speaking, chemical process speeds are related exponentially to temperature.

      Yes. What that means is that reactions that are "just right" on earth will be too slow on Titan. But there are almost certainly equivalent reactions that would be too fast at our temperatures but just right on Titan. They wouldn't even have to be radically different.
  • by caveat (26803) on Saturday September 10, 2005 @06:51PM (#13528654)
    While the methane jokes are just HI-larious, on a more serious/sci-nerd note:

    Methane is a lot less likely to be the "solvent" for life as water is. Water has a lot of very unusual properties which are important factors in the biochemical reactions of life; the most important of these is its strong polar nature. The polarity of water is a, if not the (biochemists feel free to correct me, i'm synthetic org.), major factor in protein folding; the ability of water to dissolve ionic compounds is also vitally important, e.g. nerve function. Bottom line, a nonpolar organic solvent is a *lot* less likely, if not impossible, to support life.

    • The polarity of water is a, if not the (biochemists feel free to correct me, i'm synthetic org.), major factor in protein folding

      I wonder if water has to be liquid for these properties to come into play. I am thinking about bacteria found inside Antarctic rocks.

      Also I wonder if bacteria could create their own microclimates inside ice blocks, kept liquid by their own metabolism.

    • It isn't just polarity; hydrogen bonding plays a huge part in creating the entropic effects necessary for protein folding, as well as the optimal heat capacity for maintaining a stable earth temperature.
    • by Mr2cents (323101) on Saturday September 10, 2005 @07:23PM (#13528798)
      But it still remains very interesting to study. All these problems you propose are valid, but the chemistry at those places could still be very complex, and the thing with life is, once it has started its' complexity will rise with the next generations.

      Our experience life is, let's face it, laughable. We only have one genesis to work with. The premise of liquid water is solely based on Earth observations. I don't know about you, but at least I don't know about any holiday resort on Earth next to a liquid methane lake. there just aren't any.

      If I hear about an energy source, complex carbon-based chemicals and a liquid to mix them, then, with an open mind, I think some emerging intelligence may occur after billions of years. Even if it is a freak accident, if you believe a complex system can exist for even a few hundred millions of years without one freak accident, then you're obviously not an engineer. Maybe it will not be life as we know it, but damnit Jim, it will be alive!
    • Informative post indeed.

      Just thought I'd throw it out there that this assumes the kind of life we're used to is the only kind.

      Although I suppose if we came into contact with radically different life forms, we might not even know they're there!
    • by myowntrueself (607117) on Saturday September 10, 2005 @08:08PM (#13528995)
      Then theres the lipid bi-layer that forms the cell membrane.

      Is there any analog of a lipid in methane? One which can form a bi-layer bubble?
    • there is one train of thought that life is actually a cosmic imperitive so to speak. in that if it's even remotely possible, then life will occur. the reasoning behind this is that we can find life in boiling springs, frozen rocks and many km's under the sea in total darkness. if life can survive in such conditions, then maybe it's not some rare fragile occurance, but a force in the universe which is just begging to happen anywhere possible.
      • here is one train of thought that life is actually a cosmic imperitive so to speak.

        But that's metaphysics, not science.
        There is a story of a puddle which forms in a hole in some cement. The puddle thinks "ooooo what a nice hole, it fits me perfectly, it must have been made for me. The puddle keeps thinking this right up until the last drop dries up.

        My personal opinion is that "life" is just a word with no particular meaning. Some systems appear to be "alive" to us because we are systems evolved to distingui
        • Since we haven't found something we want to call
          life anywhere other than Earth yet, we are looking at a 0% chance based on past results.


          From a purely statistical perspective, this is incorrect. The sample size is not large enough for any conclusions to be drawn about the frequency of life throughout the universe, or even just the galaxy.
    • The polarity of water is a, if not the (biochemists feel free to correct me, i'm synthetic org.), major factor in protein folding;

      Proteins fold no matter what environment they are in, they simply fold differently in different environments. There is no reason to believe that folding in solvents other than water would be any worse for evolving life than folding in water.

      the ability of water to dissolve ionic compounds is also vitally important, e.g. nerve function

      Organisms on Titan may dispense with all thos
  • Great! (Score:4, Funny)

    by Baloo Ursidae (29355) <dead@address.com> on Saturday September 10, 2005 @06:51PM (#13528655) Journal
    Now we have a lifeless planet full of transit bus fuel. Just have to get it here...
    • Now we have a lifeless planet full of transit bus fuel. Just have to get it here...

      You only get energy out of the methane if you combine it with oxygen. Personally I need oxygen to breathe. Also you would be importing carbon from Titan, which would become carbon doxide on Earth.

  • I wonder. (Score:2, Interesting)

    by Poromenos1 (830658)
    If there are two planets capable for sustaining life (well, one is. I don't know about Earth), how many are there in the entire universe?
    • Right, that was supposed to read "two planets in the same solar system".
    • Low. From what I understand, most of the star systems we've been able to watch closely have superjovian planets in orbit around them, and they don't bode well for life. Jupiter itself is yet another "sweet spot," big enough to sweep the solar system of most of the extinction-causing comets/asteroids/etc, but not so big as to suck us up. Planets that are 10's or 100's of jovian masses don't allow for many other planets (let alone rocky planets with a fluid iron core at the correct distance from the system
      • From what I understand, most of the star systems we've been able to watch closely have superjovian planets in orbit around them

        That was a long time ago, and it was only because the doppler-shift techniques used for detecting them were intially only sensitive enough to detect massive super-jovian planets.

        If you take a look at an extra-solar planets catalog [obspm.fr] you'll find lots of sub jovian planets. Note that a lot of them have pretty short periods, but again this is more a feature of the way they're detected, a
  • by kevin777 (905808) on Saturday September 10, 2005 @07:25PM (#13528811)
    Maybe we should be looking for some life forms similar to these: Methane Ice Worms [wikipedia.org]

    Image here. [psu.edu]

    Text:

    Methane clathrate deposits in the ocean floor have been found to be inhabited by polychaete worms of the species Hesiocaeca methanicola. The worms colonize the ice-methane solid and appear to survive by gleaning bacteria that in turn metabolize the clathrate. In 1997, Charles Fisher, professor of biology at Penn State, discovered this remarkable creature living on mounds of methane ice under half a mile of ocean on the floor of the Gulf of Mexico.

  • Sure... sounds great.. but as far as I know... methane boils at -161.45 C (111.55 K). That's not a very sweet spot for most biological systems I can think of.
  • Pointless what-if? (Score:2, Interesting)

    by PromANJ (852419)
    Sometimes I've wondered what would happen if we could (magically) replace our moon with Titan. It's larger than the moon so tidal effects and animal life here on earth will be affected of course, but what would happen to Titan's atmosphere? Huge greenhouse effect?
    Europa would be an interesting candidate too... but maybe this sort of speculation belongs in the 'Who would win: Skeletor vs Dr.Doom' category.
    • but what would happen to Titan's atmosphere? Huge greenhouse effect?

      Possibly. But not for very long, at least in the geological sense. Titan's able to maintain its dense atmosphere because it is so bitterly cold. The kinetic energy of its atmospheric gas molecules is not very high, so Titan's weak gravity is able to hold onto them. With significant heating, the atmosphere would bleed away.

      Quite a lot of Titan is made out of ices. These will replenish the escaping atmosphere, for a while. But it also means
  • How is this meant with the boiled water? That it boiled because of the greenhouse effect? I read several times that Venus would be habitable (although surely not very pleasant, and mostly a desert world) if the greenhouse gases weren't there, and a earth-like atmosphere would be in their place.
    • Re:Sure about Venus? (Score:3, Informative)

      by lorelorn (869271)
      Venus would probably be habitable if it had an earth-like rotation. But it turns so slowly that a day is slightly longer than a year.

      The additional heat that it receives from the sun, combined with that length of exposure to it, meant temperatures soared.

      The atmosphere is mainly Sulphur Dioxide. The planet has been wrought with volcanism in the past, so much so that the whole surface is about the same age.

      Any water Venus may have had is long gone.

      The thick atmosphere acts as a blanket, trapping the heat

    • unless you've got an adimantium spine and legs I don't think humans will be living on Venus. The gravity alone is enough to crush a man like a empty soda can. The environmental pressure doesn't help either... from my understanding.
  • Article assumption (Score:2, Insightful)

    by lorelorn (869271)
    The article is making a pretty long assumption in equating 'habitable' with 'geologically active surface'.

    Surface life may well prove to the the rarity.

    Somewhere like Ganymede, or Europa, has a far greater habitability beneath the surface.

    Sub-surface regions seems generally more likely to allow life to get started than surfaces. A bit of activity there is good, as life thrives in changing rather than fixed environments (as far as we know).

    Even life on earth began below the surface, in the oceans.

    Sub-surf

  • by Spoing (152917) on Sunday September 11, 2005 @12:09AM (#13529890) Homepage
    While you do have a propensity towards green women, the smell captin...how do you get past the smell?
  • From TFA:
    Venus is about the same size as Earth. But it is so close to the Sun that any water it had must have boiled off. As such, there is no hydrological cycle and no tectonic activity, says Lunine.

    I'd really like to know what connection Lunine thinks there is between tectconic activity isn't related to water in any way. Living as I do in Los Angeles, I'm rather familiar with it.

    • Surprisingly, I think there is quite a lot. Most of the minerals that make up Earth's crust contain water, and water, under pressure is drawn down into the crust at spreading faults. Also the carbonate minerals would not exist without long-lasting oceans where CO2 and silicate rocks can slowly combine. These hydrated and carbonate minerals act, I think as a lubricant to plate movements. I am not a geologist, but I'm sure I read this somewhere once. I can't quickly find confirmation.
      • It's correct that fault moovement and plate tectonics does not require water or other fluids, but in the majority of cases large shear-zones and falut systems show that water or other fluids (CO2, SO2) may have contributed to the ease of moovement. For instance in many thrust fault systems the sole throust is often located in shales which is rich in hyrdous minerals such as biotite, muscovite, chlorite or clay minerals. These minerals often act as the geological equvivalent of grease.

        In the case of thrust
  • by baudbarf (451398)
    So... our early Titan colonies will be plastered with "ABSOLUTELY No Smoking" signs.
  • Titan is much like the Earth with winds, rains and tectonic forces but instead of water it has an abundance of methane.

    So to get life you need 4 elements?
    Wind = Air;
    Tectonic Forces = Earth;
    Liquid Methane = Water;
    And Fire would be... Required temperature or lightning?

    Storm. In an ocean or just on a coast lightning striking something? Perhaps that's how life is born?

    Not that I have any idea what I'm talking about... :)

  • Hmmm... You'd think that after 65 bazillion years, a lifeform would have evolved that uses methane instead of water. Ah well...

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