[ExI] Eternity in six hours: intergalactic spreading of intelligent life and sharpening the Fermi paradox
eugen at leitl.org
Tue Sep 10 11:54:58 UTC 2013
On Tue, Sep 10, 2013 at 12:41:21PM +0100, BillK wrote:
> We don't know everything - yet.
We know pretty much everything *relevant* about prebiotic
chemistry necessary for emergence of life.
Phys.org is a terrible site. It is always a good idea to
hit the original papers, they at all bother to cite those.
> New research has revealed that chemical reactions previously thought
> to be 'impossible' in space actually occur 'with vigour,' a discovery
The abstract alone says no such thing.
Understanding the abundances of molecules in dense
interstellar clouds requires knowledge of the rates
of gas-phase reactions between uncharged species.
However, because of the low temperatures within
these clouds, reactions with an activation barrier
were considered too slow to play an important role.
Here we show that, despite the presence of a barrier,
the rate coefficient for the reaction between the
hydroxyl radical (OH) and methanol—one of the most
abundant organic molecules in space—is almost two
orders of magnitude larger at 63 K than previously
measured at ∼200 K. We also observe the formation
of the methoxy radical product, which was recently
detected in space. These results are interpreted
by the formation of a hydrogen-bonded complex that
is sufficiently long-lived to undergo quantum-mechanical
tunnelling to form products. We postulate that this
tunnelling mechanism for the oxidation of organic
molecules by OH is widespread in low-temperature interstellar environments.
Now that sound a little less exciting, doesn't it?
> that could ultimately change our understanding of how alcohols are
> formed and destroyed in space - and which could also mean that places
> like Saturn's moon Titan, once considered too cold for life to form,
Thought by whom? Liquid water and water/ammonia are pretty
common all over the solar system.
> may have a shortcut for biochemical reactions.
These are not biochemical reaction. This is prebiotic
astrochemistry. Necessary, but not sufficient.
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