[extropy-chat] What if Dyson spheres are obsolete? (was the Drake Equation)
asa at nada.kth.se
Fri Oct 27 09:31:51 UTC 2006
The Avantguardian wrote:
> One of the "possibilities" that I think you guys seem
> to be missing is that it may turn out that harnessing
> dark/vacuum/zero-point energy may actually be easier
> than building a Dyson sphere.
To join with the choir, why do you think this? I could make the claim that
breaking the law of conservation of angular momentum is even easier than
building an electric motor - but without any idea of how to do it the
claim just becomes an unsupported claim.
Vaccum and zero-point energy appears to be highly entropic and/or
isotropic and you need a difference to set up a thermodynamic engine. It
is unlikely you could get any energy from suffling them around within
their own domains. If ZPE or dark energy are to be regarded as istropic
heat reservoirs with a different temperature than the reservoir of the
visible universe then one could get energy by having a heat flow between
them. But if this was easily possible it would have happened a long time
ago, likely during the big bang. There might still be some clever way of
doing it that doesn't naturally occur, but I haven't seen any convincing
idea of how to do it.
One of the funnier approaches I've seen was to use Casimir forces to
extract energy from two horisontal plates by having them move together
vertically, then slide them apart horisontally, returning them to the
original position. Alas, a careful analysis (I have the paper *somewhere*)
show that there is Casimir forces resiting the return to the original
state in such a way as to make the energy gain zero.
I'm open for the possibility that there is some magical physics out there,
because I think the universe looks even M-brain empty. There ought to be a
few von Neumanns out there anyway, and we are not seeing anything. My
guess is that there is some physics that once discovered leads to a very
discreet civilization. Hopefully it is of the baby universe or moving down
to the Planck scale kind, and not of the kind that any sufficiently
advanced civilization can wipe out any other civ it knows about instantly
anywhere and hence keep very, very quiet.
Oxford Uehiro Centre for Practical Ethics
Philosophy Faculty of Oxford University
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