[FoRK] SETI and the Cosmic Quarantine Hypothesis

Kevin Elliott k-elliott
Mon Oct 24 09:23:40 PDT 2005


At 19:05 -0700  on  10/23/05, J. Andrew Rogers wrote:
>My formerly strong chemistry background has atrophied beyond recognition,
>but I believe the important difference between carbon and silicon is that
>carbon has a much simpler and stronger electron structure, lacking the outer
>d-orbitals that silicon has, making it a more robust building block for
>complex molecular structures.  That the chemistry of life is overwhelming
>biased toward p-orbital elements despite no shortage of d-orbital elements
>in our environment is not likely to be an accident.
>
>Electron orbital structures explain quite a bit about a lot of things, but
>most people forget them as soon as they are taught them.  Magnetism in
>materials, for example, is all about spin alignment in orbital shells.

Yes!  That's what I was trying to remember...  My big problem with 
the "silicon based life" meme is that their is no evidence in nature 
or the lab that silicon can replace carbon in very large molecules 
(i.e. proteins).  It's a cute "how could life be different?" answer, 
but I don't see how it could happen in our universe.
-- 
______________________________________________________
Arguing with an engineer is like wrestling with a pig in mud.
After a while, you realize the pig is enjoying it.
______________________________________________________
Kevin Elliott   <mailto:kelliott at mac.com>
AIM/iChatAV: kelliott at mac.com  (video chat available)
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