[extropy-chat] ET is a Bacterium was Dark Matter and ET.

[Mike Lorrey]

--- The Avantguardian <avantguardian2020 at yahoo.com> wrote:
 
> --- BillK <pharos at gmail.com> wrote:
> 
> > Why switch to talking about bacteria and kudzu? I
> > doubt if they have
> > the capability to colonise the galaxy. 
> 
> Well the kudzu are screwed. But bacteria on the other
> hand may be the only form of life that HAS colonized
> the galaxy so far. There are many biologists (Francis
> Crick and myself for example) that believe that life
> did not originate on Earth, instead it originated
> elsewhere and colonized the then recently cooled
> Earth. This theory is called pan-spermia. Aside from
> the fact that there is no real evidence, fossil or
> otherwise, of an "RNA world" on ancient earth, there
> are reasons that it is a valid origin theory. It seems
> very likely that all life on earth came from a single
> progenitor ancestor. If life just kind of happened
> here, then I think you would expect to see different
> clades of life starting concurrently but instead it
> radiated out from a single form. Other lines of
> evidence include, nearly uniform genetic code, same
> fundamental metabolic pathways, same 20 amino acids,
> and same chirality.

Just because we have a uniform genetic code doesn't speak anything to
the origins of life. All it indicates is that a life form with that
genetic code either arose first, or outcompeted other, less efficient
or more flawed species of bacteria arose and exterminated everything
else (just as all humans can be genetically traced back to one common
ancestor who was not necessarily the first of his or her species and
gender). The progenitor bacteria could have arrived from space or
arisen spontaneously here, we can't tell from the evidence, EXCEPT for
some geological information:

At that early date in Earth's development, Earth's atmosphere was 52
times thicker and denser than it currently is, which would reduce odds
of meteoric/cometary material containing bacteria surviving reentry.
This early atmosphere had to be reduced to limestone rock by lifeforms
before it became thin enough for meteorites to survive reentry. Of
course, there was a lot more material incoming then than now, so odds
of large impactors were much greater then than now.


Mike Lorrey
Vice-Chair, 2nd District, Libertarian Party of NH
"Necessity is the plea for every infringement of human freedom.
It is the argument of tyrants; it is the creed of slaves."
                                      -William Pitt (1759-1806) 
Blog: http://intlib.blogspot.com


		
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