On 11/6/2014 5:59 PM, Bruce Kellett wrote:
LizR wrote:
On 7 November 2014 12:32, Bruce Kellett <[email protected]
<mailto:[email protected]>> wrote:
I have not seen your arguments for this, being new to the list, but
the expansion of the universe is a universal consequence of general
relativity. So it is built into the laws of physics, and has nothing
to do with whether or not there ever was a period of rapid inflation.
Expansion or collapse is a consequence of GR, certainly. However I was thinking on a
larger scale with the EI comment, since EI seems to necessitate the existence of
expanding universes. Not sure that it can be counted as a TOE though, so it's still in
need of ultimate explanation..
The AoT comes from the third law of thermodynamics and has little to
do with the expansion of the universe. Entropy increases in the same
direction as the expansion solely because the universe 'began' in a
state of very low entropy. (The Past Hypothesis).
I didn't realise there was a 3rd law, but anyway - saying the U began in a low entropy
state begs the question - why did it? The big bang fireball was more or less in
thermodynamic equilibrium as far as I know, and if it had stopped expanding it would
have rapidly reached that stage. My point is to explain the
Sorry -- typo. I meant the second law, of course.
I agree that the past hypothesis, while it explains the thermodynamic AoT, itself stands
in need of explanation. This is the great unsolved problem of cosmology -- at least
according to many cosmologists. The initial big bang might be assumed to be in
thermodynaic equilibrium, but that is essentially the same assumption as the assumption
of low entropy. The question remains as to why it was in equilibrium. Generic creation
events might actuallybe expected to produce extremely lumpy universe down to the
smallest scaels. I.e., state with very high entropy.
What would be the highest possible (and therefore most probable) initial state? A single
black hole? From an information theoretic viewpoint a universe inflating up from a Planck
scale patch would seem most likely - doesn't require any information input.
Brent
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