Regarding the exchange below -- I would argue that the BBU must be an FLU. If not, then we would have no explanation of why all nonequilibrium locales that we know of within the BBU impose the constraint that dS>0 locally. That is, we would be unable to understand why we cannot extract all the energy in an energy gradient to do work instead of, as it is, extracting at best only about 50% of the dissipated energy as exergy. The Big Bang explains this as a result of universal expansion having produced nonequilibrium material locales that were unable to keep in equilibrium with the expanding U in which all energy gradients were left metastable and 'eager' for dissipation.
STAN
Tony,
Thanks for your thought-provoking comments.
Can it be that there are many universes, depending on how one defines
them? For example, the universe defined on the basis of the Big Bang
theory, and the one defined based on the first law of thermodynamics
(i.e., the universe wherein the statement, "The energy and matter of the
Universe remains constant", holds). For convenience, we may refer to the
former as the Big Bang universe (BBU) and the latter as the first-law
universe (FLU). If the boundary of BBU is either undefinable or porous
(due to the Heisenberg uncertainty principle?), we can still have FLU if
BBU happens to contain FLU, i.e., BBU > FLU.
I would not be surprised at all if such a possibility has already been
discussed among cosmologists, logicians, and/or philosophers?
Sung
On 06/08/2008, at 2:02 PM, (Sungchul Ji) wrote:
*The Universe by definition doesn't even have any boundary and hence
cannot exchange any matter or energy with it.
I'm starting to see that reflexive acceptance of the assumption that
such a definition is in any way related to the world we find ourselves
in might be contributing significantly to lack of progress in
understanding the bigger picture.
At any moment, our cosmos can be seen as bound by various event
horizons: the Big Bang at the Hubble radius and many black holes
within. Those event horizons are all very porous, but each in one
direction, the CMB flux entering from (near) the Big Bang horizon and
anything that strays too close exiting through the black hole horizons.
In 'Three Roads to Quantum Gravity', Lee Smolin argues that we can't
know anything beyond these event horizons, then goes on to propose an
evolutionary scenario connecting the two (a scenario I have some
sympathy for but which I still doubt is yet sufficient to give us a
full explanation for conservative physics by natural means). But the
inference relevant here from Smolin's first point is that we should
not use fact of the Big Bang to jump to a conclusion that even the
complete "Universe" (for want of a better word) produced by the Big
Bang is even bound, let alone Closed or Isolated in the sense Sung
uses for clearly confined systems.
I don't want to take this any further for now. It is just that I have
developed an allergy to the reflexive assumption that local truths can
be safely applied to global considerations. There is not even a way to
get evidence as to whether they can or cannot.
Tony Smith
Complex Systems Researcher
Meme Media
Melbourne, Australia
http://www.meme.com.au/
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