starship-design: Re: Aliens, why haven't they contact us?

[jimaclem@juno.com]

On Fri, 18 Jul 1997 18:47:05 +0200 (MET DST) Zenon Kulpa
<zkulpa@zmit1.ippt.gov.pl> writes:
>> From: jimaclem@juno.com
>> 
>> Just a thought to consider folks.  All living organisms on this 
>planet,
>> including viruses have DNA and RNA constructed from the same four
>> proteins, 
>>
>Correction.
>The components listed below are not proteins, but base
>components of nucleotides that are segments of DNA and RNA.
>They code for sequences of amino acids that finally
>constitute proteins.
>
>> adenine, cytosine, guanine and tyrosine.  
>>
>Correction.
>In DNA occur: adenine, cytosine, guanine, and thymine;
>in RNA occur: adenine, cytosine, guanine, and uracil.
>Tyrosine is an amino acid and hence is a component of proteins.
>
>> (And I do mean ALL
>> life forms on this planet, from viruses to trees to us).  The 
>chances
>> that an alien microbe, or anything else, would use these same 
>proteins
>> seem rather small, thus rendering them and us relatively harmless to 
>each
>> other since we cant read each other's cellular codes.
>> 
>The harm from microbes does not come from reading our
>cellular codes. The two main sorces of harm are:
>- eating vital components of our bodies (e.g., cellular
>  membranes, cellular proteins), hence disrupting 
>  their functioning;
>- releasing waste substances that have toxic (disrupting) effects
>  on biochemical pathways in our cells.
>
>Both types of harm can be inflicted by alien microbes, if only
>they are able to survive in the environment of our organisms, 
>which requires:
>- being resistant to disruptive (toxic, immune-action)
>  influences from substances and enzymes in our cells,
>- being able to "eat" (metabolize) substances (e.g., proteins)
>  occuring within our bodies.
>For the alien bacteria to be able to do that, it does not
>have to have even remotely similar biochemistry to ours,
>not speaking about the same genetic code...
>E.g., microbes living on oceanic vents metabolize
>and thrive on inorganic substances (mostly toxic to us humans),
>which substances have quite different composition and chemistry
>than the biochemistry of the microbe bodies.
>
>Hence, little can be said IN GENERAL about possible
>effects of alien microbes on our planet unless SOMETHING
>more specific is known about their (bio)chemistry.
>
>However, from the general knowledge about requirements
>of very precise tuning of two chemistries in order to made
>them immune to each other influences follows that it is very
>improbable for them NOT to interact chemically.
>And such interaction is most probable to DISRUPT
>biochemical workings in BOTH sides. Hence, the most
>probable effect would be that we and aliens are
>MUTUALLY TOXIC, hence the one with less numbers
>of organisms within the contact area will perish, 
>possibly doing before that considerable damage to the other 
>(remember "War of the Worlds"...).
>With full clash of comparatively similar number of organisms,
>BOTH sides may perish (or be significantly damaged, beyond
>repair of their original environment).
>
>-- Zenon
>
OOPS!  Okay, I sit corrected, looks like my biology slipped.  Thanks for
the correction.

Jim