Now if that thread title don't bring the ladies rushing in, nothing will!

Seriously, I've been puzzling over the implications of ekpyrotic theory for the cosmological argument. It has been suggested that the brane activity which supposedly gave rise to the big bang could have been occuring in sub-space from an infinite past.

What does the 2nd law of thermodynamics have to say about this? Does entropy hold in the world of branes and string theory? If so, then the process of these wandering branes could not have been going on from forever, or else the system would have wound down by now. If I'm right, then that would seem to suggest that the ekpyrotic theory does not avoid the finitude of time, nor the necessity for energy to be put into the system from without the system at some finite point in the past. Thus the cosmological argument could be maintained, though in a different form.

Whaddya think? And are there any articles on the net which deal with ekpyrotic theory and the second law of thermodynamics? Thanks!

Originally posted by luvluv

Now if that thread title don't bring the ladies rushing in, nothing will!

Seriously, I've been puzzling over the implications of ekpyrotic theory for the cosmological argument. It has been suggested that the brane activity which supposedly gave rise to the big bang could have been occuring in sub-space from an infinite past.

What does the 2nd law of thermodynamics have to say about this? Does entropy hold in the world of branes and string theory? If so, then the process of these wandering branes could not have been going on from forever, or else the system would have wound down by now. If I'm right, then that would seem to suggest that the ekpyrotic theory does not avoid the finitude of time, nor the necessity for energy to be put into the system from without the system at some finite point in the past. Thus the cosmological argument could be maintained, though in a different form.

Whaddya think? And are there any articles on the net which deal with ekpyrotic theory and the second law of thermodynamics? Thanks!

It's my understanding that the laws of thermodymics are observed properties of our current macro-universe; simple descriptions of how our universe seems to behave in statistically leaning mathematical form. They are not necessarily operative at or before (if the concept of before even has meaning in this context) the Big Bang.

Originally posted by luvluv

Now if that thread title don't bring the ladies rushing in, nothing will!

Seriously, I've been puzzling over the implications of ekpyrotic theory for the cosmological argument. It has been suggested that the brane activity which supposedly gave rise to the big bang could have been occuring in sub-space from an infinite past.

What does the 2nd law of thermodynamics have to say about this? Does entropy hold in the world of branes and string theory? If so, then the process of these wandering branes could not have been going on from forever, or else the system would have wound down by now. If I'm right, then that would seem to suggest that the ekpyrotic theory does not avoid the finitude of time, nor the necessity for energy to be put into the system from without the system at some finite point in the past. Thus the cosmological argument could be maintained, though in a different form.

Whaddya think? And are there any articles on the net which deal with ekpyrotic theory and the second law of thermodynamics? Thanks!

I don't know of any such articles but have had the same kind of thoughts about this. The generality of the laws of thermo in "ordinary" 4-D space-time makes me suspect that they also applies to branes, strings &c. & if that's the case then some version of Tolman's old argument about the effect of dissipative processes in Friedmann-Lemaitre models - i.e., that they "pump up" oscillations from one cycle to another - may well hold for ekpyrotic theory too.

Originally posted by George Murphy

I don't know of any such articles but have had the same kind of thoughts about this. The generality of the laws of thermo in "ordinary" 4-D space-time makes me suspect that they also applies to branes, strings &c. & if that's the case then some version of Tolman's old argument about the effect of dissipative processes in Friedmann-Lemaitre models - i.e., that they "pump up" oscillations from one cycle to another - may well hold for ekpyrotic theory too.

Be warned George, Socrates will tell you that your physics is wrong and then the thread will be closed.

Enjoy yourself on this discussion.

Originally posted by kuboes1831

Be warned George, Socrates will tell you that your physics is wrong and then the thread will be closed.

Enjoy yourself on this discussion.

I stated my suspicion about thermo applying to branes as just that, a suspicion.
If Socrates or anyone else can either prove or disprove it I'd be happy to see it. FWIW Tolman's argument is in his 1934 book (recently reprinted by Dover), _Relativity Thermodynamics and Cosmology_. I'll also take the liberty of mentioning a relatively elementary (& in some ways limited) proof of his result
in International Journal of Theoretical Physics 33, 1047, 1994.

Shalom,
George

Originally posted by luvluv

Now if that thread title don't bring the ladies rushing in, nothing will!

Seriously, I've been puzzling over the implications of ekpyrotic theory for the cosmological argument. It has been suggested that the brane activity which supposedly gave rise to the big bang could have been occuring in sub-space from an infinite past.

What does the 2nd law of thermodynamics have to say about this? Does entropy hold in the world of branes and string theory? If so, then the process of these wandering branes could not have been going on from forever, or else the system would have wound down by now.

1) The function f(t) = 1/(1+exp(-t)) has been strictly increasing for an infinite amount of time and hasn't reached its maximum yet. Thus the argument "if it had been going on for an infinite amount of time, it would be wound down by now" is faulty.

2) Even in our 4-dimensional world, the 2LoT has been formulated for systems within a region, thus with a boundary. It is highly dubious whether it is true in any infinite universe; there is no reason to believe that the boundary terms would in general go to zero as we inflate the region to cover the whole universe, and try to argue about an "entropy of everything".

In the higher-dimensional world of branes, we obviously can say even less about the "entropy of everything" (or whether the arrow of time has any meaning there).

Originally posted by DunnySaze

It's my understanding that the laws of thermodymics are observed properties of our current macro-universe; simple descriptions of how our universe seems to behave in statistically leaning mathematical form. They are not necessarily operative at or before (if the concept of before even has meaning in this context) the Big Bang.

Laymen seem to have the view that the laws and theories used by science are believed by scientists to be the actual rules of existence. They are not. They are simply the laws and rules developed by humans to describe the nature and history of existence as we see it. This does not detract from their validity, but you cannot take these same laws and theories and extrapolate them beyond their intended scope.

An example of this false logic is that because history is temporal, it implies temporality. The theories laws, conclusions and beliefs do not imply anything beyond the scope of the application within their disipline.

Originally posted by HRG_new

1) The function f(t) = 1/(1+exp(-t)) has been strictly increasing for an infinite amount of time and hasn't reached its maximum yet. Thus the argument "if it had been going on for an infinite amount of time, it would be wound down by now" is faulty.

2) Even in our 4-dimensional world, the 2LoT has been formulated for systems within a region, thus with a boundary. It is highly dubious whether it is true in any infinite universe; there is no reason to believe that the boundary terms would in general go to zero as we inflate the region to cover the whole universe, and try to argue about an "entropy of everything".

In the higher-dimensional world of branes, we obviously can say even less about the "entropy of everything" (or whether the arrow of time has any meaning there).

I agree about your 2d point. Remember that all I was doing was "suspecting", not asserting. Tolman's result is for a closed (positive curvature, finite) space because within standard general relativity that's the only kind (at least among homogenous & isotropic spaces) for which speaking about a cyclic universe makes sense.

Your 1st statement is true but doesn't affect the argument. The semi-Newtonian way of stating Tolman's result (& this is what I worked out in the paper that I mentioned) is that - assuming you can get a closed universe to bounce at some minimum scale factor - entropy increases from one cycle to another. That means that there's an increase in gravitational mass which drives the oscillations to higher & higher amplitudes. (The universe doesn't "run down" but actually gets pumped up by dissipation - a counterintuitive result which is what got me interested in this in the first place.)

There is also a 1976 paper by G. Neugebauer & E. Meier (Annalen der Physik 7,33, 161) in which they develop an exact general relativistic model with bulk viscosity & show that if the parameters of the model obey a certain condition there will be a stage at which the universe will make a final bounce and take off, never to recontract.

Shalom,
George

Do these ideas assume a preexisting plurality? Are there any theories out there that describe the "creation" event from a monistic reality?