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Space Science

Hydrocarbon Rain Swells Titan's Lakes 110

Rob Carr writes "According to the Cassini team, 'Recent images of Titan from NASA's Cassini spacecraft affirm the presence of lakes of liquid hydrocarbons by capturing changes in the lakes brought on by rainfall.' The northern lakes are now larger following a period in which hydrocarbon clouds covered their skies. (The research was published in the journal Geophysical Research Letters.) This change adds to the evidence these areas are indeed hydrocarbon lakes. But this discovery raises several more questions: where is the methane in the atmosphere coming from, and how long can this complex hydrocarbon cycle on Titan go on? The new evidence emphasizes the need for another mission to Titan."
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Hydrocarbon Rain Swells Titan's Lakes

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  • by Cally ( 10873 ) on Saturday January 31, 2009 @09:32PM (#26681245) Homepage
    I actually shelled out $9 to read the Geophysical Review Letters paper [agu.org] (I take my armchair planetary science geekery pretty seriously, but sadly not enough to justify journal subscriptions.) One possibility mentioned is sub-surface reservoirs as a possible source keeping the atmosphere topped up. (Note that unlike on earth, where methane has an atmospheric lifetime measured in weeks, at Titan it's millions or tens of millions of years.) Another interesting thing is the description of GCMs (global circulation models) and evidence of classical, earth-style Hadley cells, a major feature of earth's climate.
  • Re:bad modding (Score:2, Informative)

    by nmb3000 ( 741169 ) on Saturday January 31, 2009 @09:41PM (#26681285) Journal

    You've been modded funny, but historically, the vast majority of wars seem to have been fought over resources

    I see this stated as a given fact all the time, but when I stop and think about it, I'm not sure it's really the case. Sure, the lack of resources makes a great scapegoat, and it's been used for some conflicts, but most modern wars seem to be about something else.

    Feel free to correct me if I'm wrong, but here's what I came up with off the top of my head. (I don't consider a goal of "take over the world" as a need for resources. At some point, even if they say it is, resources isn't a valid argument anymore.)

    • Crusades - Religion, not resources
    • American revolution - not resources (at least not entirely, Britain probably did want access to North American resources)
    • War of 1812 - trade restrictions might be considered resources, but more comes down to one nation interfering with another
    • World War I - Not resources, largely due to a domino effect of alliances
    • World Ward II - Not resources, though Germany and others claimed they wanted "room to grow", true goal was larger than that. That said, Japan might have a valid claim to resources
    • Cold War - Not resources, primarily ideological
    • Vietnam - Not resources, also largely ideological

    I think "classic" wars, that is ones > 2000 years ago, were largely about resources. There was a lot of new and unclaimed (or tentatively claimed) land that was pretty much up for grabs. However, since the political layout of the world has settled somewhat, people are also finding new reasons to kill each other. Resources is still a reason used (

  • Re:bad modding (Score:2, Informative)

    by nmb3000 ( 741169 ) on Saturday January 31, 2009 @09:45PM (#26681307) Journal

    ...whoops. I was saying:

    Resources is still a reason used (almost anything in the Middle East since 10,000 BC, for example), but to say that 99% of conflicts are due to resources as someone did isn't true. It's just a scapegoat people and countries try to use since it sounds valid (but we need this!) but it belies the true intent.

    Didn't even get a chance to read the previous post before submitting. Oh well.

  • Re:bad modding (Score:4, Informative)

    by techno-vampire ( 666512 ) on Saturday January 31, 2009 @10:04PM (#26681403) Homepage
    The official reason for the Crusades may have been religion, but it's amazing how many crusading knights ended up as major land owners in the Holy Land. The Pacific section of WW II was all about resources, as Japan's Greater East Asian Co-Prosperity Sphere should make clear. Asia ruled by Asians instead of Europeans was just a veneer to cover over the way the Japanese were grabbing control of the iron, coal and oil their economy needed, and the rice to feed their people.
  • Re:bad modding (Score:4, Informative)

    by Fjandr ( 66656 ) on Saturday January 31, 2009 @10:30PM (#26681521) Homepage Journal

    I wouldn't say wars are driven by a need for resources so much as a desire for them by those in power. Power/control could be considered a resource for those driven by desire for more of it.

    Those brutally nasty wars based on warped and twisted religious/political/ethnic ideology funneled massive profits into the hands of supporters, be they from looting during the Crusades or manufacturing contracts during contemporary times. A war for resources is not so much about helping a population in general as about enriching those in power. I can't think offhand of a war that has occurred where that was not true.

    All those wars you cited ended up enriching the antagonist victors (the very definition of "a war for resources"), and would have enriched those antagonists who lost had they instead emerged victorious.

  • Re:bad modding (Score:4, Informative)

    by TapeCutter ( 624760 ) on Sunday February 01, 2009 @12:39AM (#26682037) Journal
    I think you have it upside down, resouces are the PRIME reason regardless of any percieved 'need'. When you talk about enforcing "ideology" you are talking about political/religious control of a particular territory and consequently all the resouces within it.

    Wars are never just between the two sides in the headlines, there are all sorts of factions at all sorts of levels. The underlying motivation for war comes from our shared territorial instincts [cracked.com]. I'm sure priests, politicians and crusaders would disagree but IMHO religion and politics is just the sales pitch.
  • by AaronLawrence ( 600990 ) * on Sunday February 01, 2009 @12:58AM (#26682115)

    As I read the FA, the methane from the atmosphere is lost to the surface, not into space. It evaporates from lakes but rains back again and forms "methane derived haze particles"... they think these two forms are more than evaporation... ergo there should be not much methane in the atmosphere over the long term.
    This point wasn't terribly clear in the article however.

  • by deglr6328 ( 150198 ) on Sunday February 01, 2009 @02:57AM (#26682547)

    jeez dude, you should really search, uhmmm this thing called the interwebs before letting yourself get raped by the ABSURDLY high prices these journals demand for a single paper! look. here. FREE [nasa.gov]! If you're an American YOU ALREADY PAID FOR THIS research. that's why it's on a NASA site for free. even when it isn't taxpayer funded research it's still VERY common to see a paper from a peer reviewed journal also up on a professor's personal page as a preprint or whatever.

  • by wizardforce ( 1005805 ) on Sunday February 01, 2009 @04:00AM (#26682745) Journal

    A few points of contention:
    1) methane is not an ideal gas at the average temperature of Titan.
    2) your velocity is root mean square not the velocity of all methane molecules in the atmosphere. The velocity of gas molecules is that of a bell curve not a concrete quantized single quantity. The fact is that although small by comparison, there's going to be a few methane molecules that have the velocity required to escape Titan's gravity no matter what the temperature. Granted the number of methane molecules capable of escaping increases dramatically with temperature... there should be enough that can escape to make millions or billions of years a fair approximation as to the average length of time a methane molecule stays bound in Titan's gravity well. THis is of course neglecting ionization of methane molecules caused by external radiation sources which reduce the lifetime of methane molecules captured.

  • by az-saguaro ( 1231754 ) on Sunday February 01, 2009 @02:32PM (#26685869)

    The reason that Titan is of such great interest (aside form the fact that Cassini-Huygens is giving us reams of data that we could never see from Earth), is that its chemistry is considered comparable to Earth in the pre-biotic eras. Our current hydro-nitrox environment evolved slowly due to abiotic and biotic chemistry starting with something that may be similar to what Titan now has. Somewhere in the distant past, biotic chemistry had to start in something that had high methane or other hydrocarbons. Even now, earth has extremophile niche organisms, some of which might well survive conditions comparable to Titan, to a degree.

    But, there are crucial differences. Biotic chemistry and the formation and evolution of life depend on complex molecules interacting in a solution. The ionic or soluble molecules, with nitrogen, oxygen, and sulfur, as well as C-H, which define life as we understand it, need water as the solvent. On Titan, it may exist at some thermal boundary far below the surface, but not at the top (the same reason that Jupiter's Europa, which does have water and ionic solutions in oceans near the surface is of such great interest as to the possibility of life).

    Titan is probably too cold to permit evolution. Atmospheric ionizations, lightening, deep geothermal chemistry, and so on may indeed have generated some biotic precursors - complex organics, amino acids, carbohydrates, or nucleic acids - but the chances of them being able to interact the gazillions of times needed to randomly find stable and regenerative molecules is unlikely at its ambient temperatures.

    However, the possibility that, at the right temperatures and thermodynamics, that these molecules could assemble and evolve in a methane solvent, is not beyond theoretical possibility, as long as enough nitrogen, oxygen, other atoms, (water), and energy are there to evolve the complexity of the molecules. This is what is presumed to have happened on earth.

    It is possible that current Titanic atmospheric chemistry is converting CH4 into larger hydrocarbons and other molecules, which would sequester the methane, making it "disappear". Since these molecules would be denser than methane, they might be below the observable surface, and we would not know about them. It is possible though that far enough below, where warmer, that the chemistry has become very complex, possibly pre-biotic, or perhaps even biotic. Of course, that is the point of this original article, that the hydrocarbons are there in mass quantities, so some sort of long term chemistry is going on.

    It would be interesting to take Titan's chemistry, as we have learned about it from Cassini-Huygens, put it in a laboratory bioreactor, adds some "lightening", heat, and so forth, and see what happens. In an old original Outer Limits episode from the 60's, they did just that, and some spooky creature evolved - how prescient!

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