🚀 go-pugleaf

In article <BwxxDo.66t.1@cs.cmu.edu> nickh@CS.CMU.EDU (Nick Haines) writes:
|In article <1346@tdat.teradata.COM> swf@teradata.com (Stanley Friesen) writes:
|
|But what we do know is that simply putting lots of organic chemicals,
|amino acids, what-have-you together, even in planetary quantities for
|billions of years, is not likely to `generate life forms'.  ...

Yep, can't disagree here.  But whatever the process, I think it likely
to be an ubiquitous one.

| The
|current idea is that one starts with a self-reproducing system that
|does not _need_ such a finely-controlled environment (such as a clay
|mineral), that such a system can, over time, select to control more of
|its environment (a `cell') and that this environment may be suitable
|for the development of nucleic acids (or something similar). But it's
|a very long and precarious chain to get from clays to algae (or even
|to viroids). And clay minerals aren't going to be sending us any radio
|signals.

Well, here you are talking about Cairns-Smith's hypothesis/model.
I would scarcely call this the principle 'current idea', most people
studying the problem are still approaching it from the RNA/DNA angle
[based on the realization that RNA can have catalytic properties, so
proteinaceous enzymes are unnecessary].

Actually, I personally do favor Cairns-Smith's approach, but only a small
handful of people are acutally working on it.

[I disagree with him a little on a couple of issues, such as the extent
to which the early 'hybrid' forms would have "fed" on pre-existing
oranic goo and the tining of the origin of photosynthesis, but those
are fairly trivial details].

|Lest you misunderstand me, I fully support spending money on SETI:
|it's not expensive, and it attempts to answer one of the really big
|questions about the universe. But none of us really expect to find
|high-tech civilizations everywhere (for the simple reason that we
|haven't seen them yet) and I think the reason lies in that term of the
|Drake equation. When we get out there, I don't expect to find
|universal dumb life, I expect to find no life at all.

Actually, I rather expect to find bacterial level life most places.
I suspect that Earth is rather typical of planets at this distance from
stars of this class.  So the ratio of complex life forms to 'prokaryote'
type life forms is probably about the same as the *time* ratios on Earth.

It is the startling *speed* with which life appeared on Earth that convinces
me.  Any process that was not nearly inevitable would not be expected to
happen in the time frame that it now appears to have happened in (unless
Hoyle is right, that is - but that would make life even *more* ubiquitous).

The *earliest* rocks that are sufficiently intact to retain traces of life
in fact have such traces, so life appeared within a few 10's of millions to
a few hundred million years of the termination of the massive bombardment
phase (with its liquid or near liquid surface).
-- 
sarima@teradata.com			(formerly tdatirv!sarima)
  or
Stanley.Friesen@ElSegundoCA.ncr.com