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I Equilibrium chaotic environment

  1. Jul 2, 2017 #1
    Cosmological fluctuations from equilibrium are best described in the Boltzmann brain paradox. My question may very well be better suited for statistical mechanics but it has relations with cosmology so I'll post it here.

    Anyway, it is often stated that BBs will perceive chaotic observations etc. But let's forget about BBs and focus just on eventual environments and other objects that can fluctuate. In what sense will they be chaotic, so that for instance most planets that fluctuate will be highly disorganized or that most objects that fluctuate are disordered than usual structures?

    What would the Boltzmann hypothesis predict for the distribution of other objects and their state except for brains?
  2. jcsd
  3. Jul 7, 2017 #2


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    Have a care, Chaos is defined as sensitivity to initial conditions. You cannot apply the "chaotic" qualifier to a single case but rather to the dynamic evolution itself applied to many cases. Don't mix the aesthetic definition of chaos with the dynamic one. As to the question, I think "chaos" here is a pseudonym for "entropy". That brings up another related issue. How do you define the entropy of the universe as a whole. It is not additive at the quantum level so you can't just calculate the entropy of pieces and add em up.

    I would argue that the entropy of the universe as a whole (including the interiors of BH's) is meaningless. But the entropy of the observable universe is sub-maximum because it has expanded and also formed black holes (which you can think of as an "internal" expansion) which are the ultimate entropy dumps. (BH and deSitter horizons, that is to say.)
  4. Jul 12, 2017 #3


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    In the Boltzmann brain scenario, everything is in a high entropy state (think lukewarm gas mixture with uniform temperature and density) except for the brains and what is needed to immediately sustain the brains. A high entropy state is the most likely state, and the Boltzmann brain is supposed to represent the minimum deviation from the high entropy state in order to produce conscious observers.
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