LizR wrote:
On 13 November 2014 11:29, Bruce Kellett <[email protected]
<mailto:[email protected]>> wrote:
LizR wrote:
Why not? Informally, from a quantum viewpoint it makes more
states available, in a manner similar to Max Tegmartk's
calculation of how far away one's duplicate is in a level 1
multiverse. The analogy used by Paul Davies is that if you have
a gas at equilibrium inside a container and expand the
container, the gas will stop being at equilibrium in the new
configuration. It has more states available, and hence its
entropy ceiling has been raised. This seems to me a valid
argument. Where has Davies (and Tegmark) gone wrnog?
The problem would seem to be with Davies' analogy. If you expand a
container containing gas at equilibrium, the temperature will drop
and the entropy will rise, but this is because you have extracted
heat from the system. Moving the walls outwards means that molecules
that bounce off the walls will recoil with lower velocity --
transferring energy from the gas to the outside world. This does not
happen in the expanding universe. The gas cools, but energy is not
conserved in the expansion -- it does not go anywhere. There is no
reservoir at a lower temperature to act as a sink, and there is no
change in entropy. With no change in entropy, the gas does not cease
to be at equilibrium if it were initially so, and there is no change
in the number of available states. This is a peculiarity of GR since
energy is not globally conserved in an expanding universe.
I think Prof Davies' point is that expansion magnifies any existing
inhomogeneities, at least if the expansion is faster than the relaxation
time of the medium.
The expansion would make existing inhomogeneities extend further,
certainly. I doubt that it does much more
However you haven't addressed Max Tegmark's point, that the number of
quantum states available inside a given volume is proportional to the
volume, hence expansion allows more quantum states to exist.
Entropy is given by the number of states in phase space. Phase space
does not expand -- I refer you again to Penrose's argument.
However, all this is somewhat beside the point since any entropy bound,
whether it increases or not, is very far from saturation. Until you
thermalize the gravitational degrees of freedom, entropy will always be
almost infinitely below any supposed maximum.
Gravity is one of the laws of physics. The AoT occurs within
physics, so why not use gravity to explain what happens? The
problems arise -- as I have tried to point out -- when you ignore
gravity. Cosmogenesis is, after all, the quintessential
GR/gravitational problem.
Well, space-time starts out smooth to a very good approximation, so you
can look at the behaviour of matter within it to explain at least some
features of the AOT. You haven't yet addressed the formation of nuclei
and other bound states and why that would make no contribution to the
AOT, to the best of my knowledge (I asked for a short simple reply
because I don't have time to wade through huge responses - which is why
I also trim anything irrelevant from my posts).
I did answer your question earlier. I am sorry if my answer was too long
and complicated for you to be bothered reading it.
The comment is apposite. It is neither patronizing nor irrelevant.
No. You are partonisingly assuming I don't already know about the
possibility of making contingent facts into logical connections (not
necessities). Even if you have shown that there is no logical
connection, which isn't apparent to me (at present, at least), this
still reduces to a merely /ad hominem/ remark.
I was merely pointing out a logical error. That is neither patronizing
nor ad hominem.
Bruce
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