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Jun 05 2010

Good evidence for methane-based life on Titan

NASA has released papers based on several readings from Cassini’s recent fly-by of Saturn’s icy moon Titan. Amazingly, there’s strong evidence confirming the hypothesis that there is methane-based, hydrogen-consuming life on the surface, considering the observed chemical makeup matching very closely to several of the necessary conditions for the hypothesis.

One key finding comes from a paper online now in the journal Icarus that shows hydrogen molecules flowing down through Titan’s atmosphere and disappearing at the surface. Another paper online now in the Journal of Geophysical Research maps hydrocarbons on the Titan surface and finds a lack of acetylene.

This lack of acetylene is important because that chemical would likely be the best energy source for a methane-based life on Titan, said Chris McKay, an astrobiologist at NASA Ames Research Center, Moffett Field, Calif., who proposed a set of conditions necessary for this kind of methane-based life on Titan in 2005. One interpretation of the acetylene data is that the hydrocarbon is being consumed as food. But McKay said the flow of hydrogen is even more critical because all of their proposed mechanisms involved the consumption of hydrogen.

“We suggested hydrogen consumption because it’s the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth,” McKay said. “If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth.”

Cassini is scheduled to make a few more fly-bys, so more data is forthcoming, and I guarantee I’ll be watching for any evidence to confirm or refute this theory. One way or another, we absolutely need to do more research.

There’s a certain parsimony to the thought that life, as rare and wonderful and special as it apparently is in this universe, can arise on a planet with so much difference from our own, and in our back yard. I want there to be life on Titan, desperately, because it gives us more information we can plug into the Drake Equation. It tells us that maybe life ISN’T as rare as we think it is, and that the chemical processes that lead to abiogenesis are not as singular as we might be led to believe otherwise — it’s just that our planet, with its specific conditions, happens to be one type of place where life can flourish and intelligence can emerge over time. That doesn’t make our planet less special; in fact, it makes it more special.

That notwithstanding, I’m well aware that this universe often presents tantalizing hints at amazing possibilities that turn out to be mostly projection on humanity’s part. I will not ascribe this evidence with more portend than it has. There could very well be other natural processes at work that we don’t yet understand, as stated by the scientists in the original article; or even processes that we DO already understand, but are rare, causing the chemical states we’ve observed, without the necessity of life. There could turn out to be not terribly much special about Titan at all, in fact. We mustn’t jump to the conclusion that life exists just because that would be thrilling. Our data could be wrong, or inaccurate, or our conception of certain chemical processes could turn out to need tweaking for a special borderline case that we’d heretofore not discovered.

But a guy can wax rapturous about the possibility, right?

7 comments

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  1. 1
    Dan J

    The probability of life within our own solar system, carbon-based, oxygen-consuming, or otherwise, is something that’s always fascinated me, too. I simply find it difficult to think that we, as organisms of life, are all that special in the Universe. I can’t even begin to imagine the types of life and possibilities of civilizations that exist in our own galaxy, and the countless other strewn about our Universe.

    I’m glad that the probes we’re sending out are proving to be even more useful than the designers had hoped. Ethan Siegel at “Starts With a Bang” posted “The Land of Opportunity” just the other week about the Mars rover Discovery beginning a 12 km trip to the crater named Endeavour. The trip should take about two more years. This from a machine which was intended to operate for three months and undertake a 600 meter journey. Here we are six years and twenty kilometers later, and we’re still coming up with cool stuff that Discovery can do for us.

    Are technology and space science great, or what? I love it! From the Moon landing in 1969 (Which I can barely remember, at the age of four, on a grainy black & white console television) to the launch of Falcon 9 on Friday, it’s all amazing to me, and enthralls me still.

  2. 2
    Jason Thibeault

    Those are some absolutely beautiful pictures. And I echo the sentiment of Daneel in the comments — we have fricking robots on another fricking planet, how cool is THAT?

  3. 3
    James Carey

    I only hope it happens within my lifetime, I would hate to miss something as cool as that.

  4. 4
    Paul S.

    Most likely it will turn out to have a non-biological explanation, but I tell myself that partly so I won’t get my hopes up! It would be incredible if they actually discovered something living there, and it would radically change the way scientists and the general public look at the question of life in the universe in general.

  5. 5
    Glendon Mellow

    I only discovered your post about this today (bit behind on my reading).

    Holy black smokers! I was over the moon, reading yours and other articles today. This is what I love about life and science. This. That feeling. Right there.

    Thanks for writing about this Jason!!!!!

  6. 6
    Jason Thibeault

    I know, it’s really difficult to contain that excitement that wells up such that you’re fit to burst. I suspect it’s something like what the religious feel when they find some piece of evidence they think confirms their epistemology, because it’s a very apt parallel. Such a discovery — in our own back yard no less — would transmogrify how the world thinks about life itself.

    But we haven’t “confirmed” anything. Yet. The only thing we’ve confirmed is that we absolutely need to spend a shit-ton of money on science ASAP.

  7. 7
    Glendon Mellow

    Even if nothing is detected, it’s still amazing. the likely outcome would be that human techniques for detecting life would be fine tuned a bit more.

    As you say: get spending quick.

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