Could the size of our universe be determined by some average per volume temperature ?
The size of our observable universe is a result of the average energy density of the various components of the cosmological model (dark energy, dark matter, etc.), so it's true in that sense. Likewise, the size of the region that was at one point in causal contact would have been dependent on the energy densities prior to inflation. I don't immediately see, however, why the size of the entire universe would be given by this.
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