
Titan's atmosphere oddity consistent with methane-based life - Anon84
http://arstechnica.com/science/news/2010/06/why-is-the-hydrogen-exiting-titans-atmosphere.ars?utm_source=rss&utm_medium=rss&utm_campaign=rss
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cstross
One point I'd like to add is that you shouldn't get your hopes up about
meeting bug-eyed aliens. Titan is _cold_ \-- so cold that even if this _is_ a
metabolic signature, whatever reactions are running are probably so slow that
nothing more complex than prokaryotic bacteria has had time to evolve yet
since the formation of the solar system. And even bacterial life might be a
bit of a reach.

(This is a guess, but based on what we know of terrestrial biochemistry. Just
bear in mind that on Titan, the mean surface temperature is around -180
celsius -- methane runs like water, water ice is a rock-like substance, and so
on.)

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moultano
Yet again, Ars Technica shows that it's the only lay source worth reading on
science topics. Thanks for the great article.

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jey
Wait, why does this strike you as a reasonable article? To me it seems like
blatant pandering to the audience.

Sure, lay people _want_ there to be life out there in other places. But this
inference doesn't actually hold any water as far as I can see. In the Bayesian
formalism, the question to ask is: why do you have such a high prior
probability to there being life on titan that mere methane emissions are
enough to make that the maximum-a-posteriori hypothesis? Isn't it more
plausible that there is some other non-life chemical process generating
methane? Sure, the article gives a token acknowledgment that "the authors of
the latter paper provide a variety of ways to account for the acetylene
shortage that don't involve an organism"... but the title of the article is
pretty clearly engineered to pander to the prejudices of a scientifically
clueless audience.

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jerf
Indeed. Either there is a relatively simple unknown process going on in the
atmosphere of a planet we've never actually been to and have only the slimmest
actual knowledge, or there's a fantastically complicated unknown process
called "life". For better or for worse, the odds favor the relatively simple
unknown process, until more data comes in.

(I say "relatively" because it probably isn't trivial or we'd have a good
guess at it. But there's still quite a gulf between "we don't know what it is
yet" and "it could only be life".)

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sliverstorm
The conservationist in me always cringes whenever I hear of hydrogen or helium
gases escaping gravitational pull, because I know it's never coming back. I
always have to remind myself that the planets are ultimately doomed anyway,
and that there's a ton more gas than I can imagine, so supply is not yet in
danger of exhaustion. (that I apply these concerns to another planet I'll
probably never even get near, I have decided to simply take in stride)

Nonetheless, cool article. It's interesting how many theories are coming about
anymore involving life on satellites rather than planets. I understand they
are probably more common than small rocky planets what with the abundance of
gas giants, but are they more or less suited to life? It seems like the
presence of a massive body nearby (the planet it's orbiting) would have a big
impact. Plus, the distance from the sun would increase and decrease (meaning
light and temperature variations), and overall incumbent light would be
minimal.

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JCThoughtscream
By the time hydrogen supply becomes a problem, though, we'll either be long
gone, or able to harness it elsewhere. Probably true for other hypothetical
civilizations. Hydrogen is, after all, ridiculously abundant - and, if nothing
else, weighed down by other elements.

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gojomo
[ _panspermia_ ]

I think we're likely to discover, as our sensing and exploration improve, that
rather than being rare, life -- at least simple life -- is common throughout
the universe.

