From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Sun Jul 27 2003 - 16:55:24 MDT
On Sun, 27 Jul 2003, Spike wrote:
> The more I ponder the theme of a one-way carbon-sink
> the stronger the notion becomes, for it holds even if
> Thomas Gold's notions of hydrocarbon formation
> are correct. He is not actually arguing that pure
> carbon is formed during the process of planet formation,
> but rather the mechanics of hydrocarbon formation
> (microbes vs dinosaurs).
Spike, I would urge you to rethink this. The problem
is *not* the availability of carbon (go over the
fundamental equations of stellar nucleosynthesis).
The problem is *where* it is available within a solar
system. The problem is that most of the C gets
locked up as CO or CO2 in the outer regions of a
solar system -- the dynamics of which -- i.e. how
many comets (and what size) can you deliver to a
planet annually? becomes a critical factor.
Answer these questions -- How much C is the Earth
receiving annually from outer space? How much C
is being subducted annually? What are the radioactive
isotope levels required (in the core of initial planet
formation) to sustain carbon recycling (through volcanic
activity)?
When you can answer those questions (on a statistical
solar system basis) *then* maybe we can talk about
your perspective seriously (not that I disagree with
it but I want the beef on the table).
> Still, the carbon cycle is imperfect, and as time went
> on, we can imagine it becoming ever less efficient in
> recycing the carbon, as the crust becomes thicker and
> the mantle ever less accessible.
Spike, give me a break, you must be talking about
"cave men" being the maximal level of development.
Any advanced technological civilization is going
to trump the architecture of its planet (to the
point of disassembling it) -- so for this scenario
to work you have to make the planet very "primitive".
> It is not surprising that Robert should suggest
> the evolution of non-carbonbased lifeforms, for
> he has theorized one: the Bradburian silicon-based
> M-Brain.
Actually silicon is only a partial sub-component
of an MBrain. I thought I had made this clear in
various conversations, but in reviewing my papers
the "picture" may not be present.
Please see:
http://www.aeiveos.com/~bradbury/MatrioshkaBrains/MBlayout.html
It is a very brief document that may explain this.
> Perhaps we can see this as the fourth
> critical step in evolution, that absolutely requires
> going thru each of the first three: 1) evolution of
> life, 2) development of multicellular lifeforms,
> 3) the development of technology-capable lifeforms,
> 4) construction of MBrains.
>
> Claim: there is no possible path to step 4 without
> going thru and surviving each of the previous 3.
> Claim: the previous 3 steps absolutely require
> carbon based life.
I will not dispute (3). I would question whether (4)
is necessary -- [for example there may be loopholes
in the laws of physics as we currently know them that
enable (4) to be avoided. Certainly the jury is
still out on whether (4) [in a specific form] is
required.] But the most iffy assertion IMO might
be (2). Yes multicellular lifeforms certainly help
in the evolutionary process -- but it would seem to
be a stretch to assert this is the only path that
evolution must follow.
Robert
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