On 11 November 2014 12:34, Bruce Kellett <[email protected]> wrote:
> LizR wrote: > >> On 11 November 2014 10:32, Bruce Kellett <[email protected] >> <mailto:[email protected]>> wrote: >> >> LizR wrote: >> >> OK, so are you saying that the formation of bound states like >> nucleons has no bearing on the existence of an AOT? >> >> It certainly doesn't play a role in the origin of the AoT. Formation >> of bound states is just a routine physical process that follows >> conventional dynamical laws, including the second law of >> thermodynamics. Since the second law governs these processes, they >> are subject to an AoT. >> >> You appear to be assuming the AOT in order to explain something that >> emerged from a state in which there was no distinct AOT. The quark soup >> starts in a high energy, essentially time-reversible state (any nucleons >> that happen to form sill rapidly fall apart again) - how can the 2nd law >> apply at that point? >> > > I think we have covered this. The quark-gluon plasma is a thermal state of > only those degrees of freedom -- other degrees of freedom, particularly > gravitational, are not thermalized, so it is not a state of maximum > entropy. It is, in fact, a low entropy state compared with what might be > expected -- we could have a soup of black holes for instance, which would > have the same energy density but vastly higher entropy. Why do we not have > such a state? That is the past hypothesis -- things started in an unusually > low entropy state. > Yes, I have already agreed with this. The flatness of space-time does indeed need explaining (perhaps by inflation?). I'm talking about the (perhaps residual) entropy gradient arising from mainly non-gravitational processes, like the fact that atoms can only exist to the "future" side of a certain point in an expanding universe. The AOT we experience may be many order of magnitude away from the one theoretically attainable by gravitational processes, however I'm assuming the universe got flat somehow, and asking how, given that, the AOT of everyday life might have arisen. Maybe it only arises from flatness, but if so we need a mechanism. My suggestion is that flatness plus cosmological expansion plus our tie-symmetric laws of physics are enough to give the observed AOT. > > If the universe were not expanding, and hence cooling the initial plasma, > then the gravitational degrees of freedom would gradually become excited, > and eventually fully thermalized. The entropy would rise throughout this > process, even though no expansion is hypothesized. The second law applies > because the state has a much lower entropy than other states which are > equally likely. The second law is there in the statistics of the degrees of > freedom -- it does not have to 'emerge' from anywhere. > > In other words, the gravitational entropy would rise. I agree. And I agree that the second law applies to states in low entropy, as flat space-time clearly is. The flatness of space-time needs to be explained, but that isn't the whole story. I'm discussing whether the expansion turning the q-g plasma into bound states could contribute to the AOT that we experience, given that we're made from those bound states and live off energy generated from them inside stars. Given that the laws of physics are (almost) time-symmetric, there needs to be some mechanism by which an AOT emerges, and an obvious starting point is the observed boundary conditions on space-time. . -- 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.
