From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Thu Dec 19 2002 - 03:51:14 MST
On Thu, 19 Dec 2002, Anders Sandberg wrote:
> On Thu, Dec 19, 2002 at 02:29:59AM +0000, Christian Weisgerber wrote:
> >
> > Panspermia is strongly associated with kookiness.
Yep, having seen presentations by the primary promoters such as
Wickramasinghe I would tend to agree. But I did get a chance to
speak with him at the OSETI III conference and did some spin control.
He isn't as completely ill-informed as the public line of comment
might lead one to believe (so that's a good thing).
> Might be true, but it doesn't invalidate the hypothesis.
Yes. Its an old and "kooky" hypothesis -- but might just be
able to be refined given current knowledge of genomes resistant
to radiation (e.g. Deinococcus), interplanetary meteorites, etc.
> If panspermia is true it might affect the Great Filter in interesting
> ways. The emergence of life can be extremely rare, but interplanetary
> and interstellar spread makes this low probability be multiplied by a
> macro multiplier.
This is a very interesting area that really should be explored more fully.
I think Eugene's subsequent messages "dis" the whole interstellar spread
possibility -- *BUT* one doesn't need "LIFE" to survive interstellar
transport -- one only needs some of the components for "LIFE" to survive.
If one can get a ribosome or a proteosome or a G-coupled receptor (or at
least the blueprint for one of these) across the divide one may be a
huge step up from an evolutionary perspective. Hell, even getting the
"code" for a single DNA repair enzyme (there are dozens in the current
basic code set) across the divide probably puts one *way* ahead in the game.
Life doesn't have to survive -- its the *code* that counts.
To refute panspermia you have to make some *very* complex arguments
about the stability of DNA (which is more stable than RNA), radiation
levels, transit times, probable radiation exposures, size of a "useful"
genomic unit, probability that the destination system uses "DNA" as
its information carrier, etc.
Now as most people on the list know -- I *like* complex technical
arguments but this isn't one that I would tackle lightly.
> On the other hand the spread might be patchy - the
> seeding will be random, and the drift rate can be so slow that large
> regions have had no time yet to be reached by any spores.
As always, Anders has cut to the chase. I'm not so sure I understand
the "Great Filter" perspective since it seems to me the G.F. is based
on an evolved "intelligent" life form. That is somewhat different
from the distribution of genomic "sub-units" based on astronomical
impacts, random phenomena, etc. (I.e. one is "intentional" while the other
is "random"). But Anders does seem to sum up the essential differences.
It would appear that the question revolves around whether or not
"our" universe just happens to be in the state of the "emergence"
of intelligence. So we have a mix of genomic code being distributed
by panspermia (and slowly evolving) with current or emerging capabilities
destined to soon overwhelm it with our own self-directed evolution. All of
this combined with a lack of knowledge of what really exists (now)
outside of our light-cone. (So we could really be in a multi-state
phase space.)
What a *very* strange web it is that we weave.
Robert
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