Ben,
[[ I wonder what you mean by "thermodynamically isolated." I've taken it
to mean a system with no matter or energy interaction with an outside
system. ]]
That's pretty much it. All organisms are open in that sense -- they
require inputs and outputs of energy/matter -- and all organisms are
dissipative structures. Some nonliving things, such as hurricanes, are
also dissipative structures, but i don't think a solar system would
qualify. It would however be isolated enough to treat as
thermodynamically closed for theoretical purposes, because its
interchanges of energy with the rest of the universe (or the galaxy)
take place at a scale too far removed from us (the theorists) to be
measurable or to make any significant difference to the theory.
Strictly speaking, entropy is only defined for isolated systems, but the
fact that our measurements and our usage are necessarily imprecise does
not invalidate the concept -- as Peirce often pointed out in reference
to other concepts. Still, many theorists in ecology (including Schneider
and Sagan) prefer to focus on "energy flows" and gradient reduction
rather than "entropy". In those terms, the final cause of life on earth
might be to reduce the solar gradient as thoroughly as possible. That
would *not* be the final cause of any individual organism or species, or
even of evolutionary processes; but it would be relevant to the
origin-of-life question.
gary F.
----- Original Message -----
Gary wrote,
> Perhaps i should clarify that a dissipative structure *cannot* be an
> isolated system in the thermodynamic sense (though it may be "closed"
> in other senses
That's news to me.
I wonder what you mean by "thermodynamically isolated." I've taken it to
mean a system with no matter or energy interaction with an outside
system. A solar system in a universe otherwise empty would still run
down.
Best, Ben
}To become full, be hollow. [Waley, Tao Te Ching 22]{
gnusystems }{ Pam Jackson & Gary Fuhrman }{ Manitoulin University
}{ [EMAIL PROTECTED] }{ http://users.vianet.ca/gnox/ }{
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