Besides the quark-gluon plasma was a BEC On Fri, Nov 7, 2014 at 5:40 PM, Bruce Kellett <[email protected]> wrote:
> LizR wrote: > >> On 7 November 2014 22:30, Bruce Kellett <[email protected] >> <mailto:[email protected]>> wrote: >> >> No, my main problem with identifying the expansion of the universe >> as the origin of the arrow of time is that the expansion of the >> universe really has essential zero impact on the everyday physics of >> our experience, but we see a consistent AoT associated with >> increasing entropy in every phenomenon of our everyday experience. >> Sure, what happened in the early universe has had lasting >> consequences for our everyday life, but any connection with the >> expansion is too remote to provide a plausible explanation of the >> consistency of our experience of time. So the increase of entropy >> itself -- whose universality is easily understood -- is itself the >> origin of the AoT. >> >> >> So you don't think that the creation of bound states in the BB fireball >> is a significant contribution to the entropy gradient? >> > > No, and I don't really understand what you are trying to get at with this. > In the early stages of the Big Bang we had a period of nucleo-synthesis in > which the temperature was high enough for protons to have enough energy to > fuse together in collisions, so amounts of deuterium, helium and lithium > were formed. The exact amounts of these is a significant test of the hot BB > theory since we know enough about nuclear physics to understand these > processes. Once the expansion cooled things further, nucleo-synthesis > stopped and could only start again when collapsing dust created stars which > could ignite nuclear reactions -- and ultimately lead to supernovae which > cook higher elements. > > But all these as standard processes and proceed according to the second > law of thermodynamics just as much as the laws of nuclear physics. I find > it strange that you refer to this as 'creating negative entropy' or some > such. > > The entropy gradient can only exist because at any point in time the > actual entropy of matter and radiation is much less than its possible > maximum. This is as true in the early stages of nucleo-synthesis in the BB > as it is now. We can get on entropy gradient only if the initial entropy > was very much lower than might have been expected for a generic universe. > > The entropy gradient between the sun and earth is important, and life of > earth depends on the existence of a cold dark universe into which we can > dump our waste heat. > > > >> I don't think you can cite the "remoteness of the Hubble flow" (as it >> were) as a reason to discount expansion as a source of the AOT (I assume >> you think that because bound systems are effectively separated out from >> it?). All the matter around us was once in the big bang fireball, and if >> that's where the conditions that created the entropy gradient originated >> then we would expect there to be a connection, although it may not be an >> immediately obvious one. >> > > The entropy gradient certainly originated at the beginning because it was > a low entropy state. It was not the low entropy was somehow created by > processes at that time. If the hot BB was a quark plasma at more-or-less > thermal equilibrium, that is a relatively high entropy state for that form > of matter, but that does not excite all the available degrees of freedom. > It is only the quarks that are in thermal equilibrium, they are not in > equilibrium with the gravitational and other degres of freedom, so relative > to the maximum possible, that plasma was a low entropy state. > > Bruce > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
