Re: Reversing time = local reversal of thermodynamic arrows?

y, whatever that might be, to increase with the expansion because there is still an enormous potential for entropy to increase as gravitation comes into play. The time scale for this is much longer than the timescale of quark processes, so is not evident at early times. The main role that

Re: Reversing time = local reversal of thermodynamic arrows?

plasma was almost infinitely below the maximum possible. There is no need for the maximum entropy, whatever that might be, to increase with the expansion because there is still an enormous potential for entropy to increase as gravitation comes into play. The time scale for this is much longer than

Re: Reversing time = local reversal of thermodynamic arrows?

On Fri, Nov 07, 2014 at 12:59:28PM +1100, Bruce Kellett wrote: > LizR wrote: > >On 7 November 2014 12:32, Bruce Kellett >> wrote: > > > >I have not seen your arguments for this, being new to the list, but > >the expansion of the universe is a universal con

Re: Reversing time = local reversal of thermodynamic arrows?

On Friday, November 7, 2014 2:53:28 AM UTC, Brent wrote: > > On 11/6/2014 5:59 PM, Bruce Kellett wrote: > > LizR wrote: > >> On 7 November 2014 12:32, Bruce Kellett > >> > wrote: > >> > >> I have not seen your arguments for this, being new to the list,

Re: Reversing time = local reversal of thermodynamic arrows?

On 14 November 2014 12:58, Bruce Kellett wrote: > > No Liz, you don't want me to engage with what you say: you want me to > agree with it. > > Or disagree politely and sensibly, showing that you have understood what I've said and giving a clear explanation of why it's wrong. As other people on t

Re: Reversing time = local reversal of thermodynamic arrows?

On 13 Nov 2014, at 23:10, Bruce Kellett wrote: LizR wrote: On 13 November 2014 17:42, Bruce Kellett > wrote: Whatever the merits of that argument, it has little to do with the maximum possible entropy. Rember, that occurs when all of the mass/energy

Re: Reversing time = local reversal of thermodynamic arrows?

LizR wrote: On 13 November 2014 17:30, Bruce Kellett > wrote: I was merely pointing out a logical error. That is neither patronizing nor ad hominem. That would have been the case if you'd shown there had been such a logical error and that I had careles

Re: Reversing time = local reversal of thermodynamic arrows?

LizR wrote: On 13 November 2014 17:42, Bruce Kellett > wrote: Whatever the merits of that argument, it has little to do with the maximum possible entropy. Rember, that occurs when all of the mass/energy is in the form of black holes. We're a long w

Re: Reversing time = local reversal of thermodynamic arrows?

On 13 November 2014 17:30, Bruce Kellett wrote: > I was merely pointing out a logical error. That is neither patronizing nor > ad hominem. > > That would have been the case if you'd shown there had been such a logical error and that I had carelessly made it, which you hadn't - so yes it was still

Re: Reversing time = local reversal of thermodynamic arrows?

r universe can only > be in about a googolplex different ways (see chapter 6 in my book). > ;-) > That doesn't seem to quite address the question, so I have now asked for further elucidation. My guess is that the BB only applies to regions of the universe that are in causal contact

Re: Reversing time = local reversal of thermodynamic arrows?

, and there is no change in the number of available states. This is a peculiarity of GR since energy is not globally conserved in an expanding universe. I think Prof Davies' point is that expansion magnifies any existing inhomogeneities, at least if the expansion is faster than the r

Re: Reversing time = local reversal of thermodynamic arrows?

On 13 November 2014 17:42, Bruce Kellett wrote: > > Whatever the merits of that argument, it has little to do with the maximum > possible entropy. Rember, that occurs when all of the mass/energy is in the > form of black holes. We're a long way from that situation. In order to explain the AOT a

Re: Reversing time = local reversal of thermodynamic arrows?

LizR wrote: Well, yes, I knew someone would mention that when I typed it! And yes, I agree, the Beckenstein bound implies that - although isn't that dealing with information, rather than quantum states (leaving aside any it-from-bitness, at least) ? Or maybe the two are equivalent. I'm not su

Re: Reversing time = local reversal of thermodynamic arrows?

I've emailed Max to ask him how he gets out of this one (though not in exactly those words) so I am hoping to be elucidated. -- 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, sen

Re: Reversing time = local reversal of thermodynamic arrows?

Well, yes, I knew someone would mention that when I typed it! And yes, I agree, the Beckenstein bound implies that - although isn't that dealing with information, rather than quantum states (leaving aside any it-from-bitness, at least) ? Or maybe the two are equivalent. I'm not sure how (or if) Ma

Re: Reversing time = local reversal of thermodynamic arrows?

On Wed, Nov 12, 2014 at 6:35 PM, LizR wrote: > the number of quantum states available inside a given volume is > proportional to the volume Although it's counter intuitive the maximum number of quantum states you can put inside a sphere is actually proportional to the sphere's area not its volu

Re: Reversing time = local reversal of thermodynamic arrows?

change in the number of available states. This is a peculiarity of GR since > energy is not globally conserved in an expanding universe. I think Prof Davies' point is that expansion magnifies any existing inhomogeneities, at least if the expansion is faster than the relaxation time of the med

Re: Reversing time = local reversal of thermodynamic arrows?

LizR wrote: On 13 November 2014 00:15, Bruce Kellett > wrote: LizR wrote: On 11 November 2014 14:48, Bruce Kellett mailto:bhkell...@optusnet.com.au> >> wro

Re: Reversing time = local reversal of thermodynamic arrows?

On 12 November 2014 21:22, Bruno Marchal wrote: > > On 12 Nov 2014, at 07:58, LizR wrote: > > On 12 November 2014 15:42, John Clark wrote: > >> On Mon, Nov 10, 2014 LizR wrote: >> >> > Physical processes obey the laws of physics. The 2nd law isn't a law of >>> physics. >> >> >> The 2nd law is

Re: Reversing time = local reversal of thermodynamic arrows?

On 13 November 2014 00:15, Bruce Kellett wrote: > LizR wrote: > > On 11 November 2014 14:48, Bruce Kellett > > wrote: >> >> >> The AoT exists regardless of such processes. >> >> I don't see how. The expansion made a state with no AOT turn >>

Re: Reversing time = local reversal of thermodynamic arrows?

LizR wrote: On 11 November 2014 14:48, Bruce Kellett > wrote: The AoT exists regardless of such processes. I don't see how. The expansion made a state with no AOT turn into one that had one, by cooling the plasma to the point where

Re: Reversing time = local reversal of thermodynamic arrows?

Hi Stephen, On 09 Nov 2014, at 14:30, Stephen Paul King wrote: Hi Alberto, you wrote: "There must not be a general arrow of time since time in general relativity is local not only in his value but also its direction AFAIK" Exactly! Time can be shown to be local for QM

Re: Reversing time = local reversal of thermodynamic arrows?

ing the superposition of the vacuum state. It is the opposite in the de Broglie/ Bohm initial state, which needs a priori to be a very-high information state, to enforce (non covariantly) the particles to exist in only one term of the wave, in some chosen base. With computationalism or the MW,

Re: Reversing time = local reversal of thermodynamic arrows?

On 11 November 2014 14:48, Bruce Kellett wrote: > >> The AoT exists regardless of such processes. >> >> I don't see how. The expansion made a state with no AOT turn into one >> that had one, by cooling the plasma to the point where a phase transition >> could occur. >> > > No, we have gone as

Re: Reversing time = local reversal of thermodynamic arrows?

On 12 November 2014 15:42, John Clark wrote: > On Mon, Nov 10, 2014 LizR wrote: > > > Physical processes obey the laws of physics. The 2nd law isn't a law of >> physics. > > > The 2nd law is even more fundamental than a law of physics, it's more > like a law of logic; it's just the result of t

Re: Reversing time = local reversal of thermodynamic arrows?

On Mon, Nov 10, 2014 LizR wrote: > Physical processes obey the laws of physics. The 2nd law isn't a law of > physics. The 2nd law is even more fundamental than a law of physics, it's more like a law of logic; it's just the result of there being VASTLY more ways to be disorganized (high entrop

Re: Reversing time = local reversal of thermodynamic arrows?

LizR wrote: On 11 November 2014 13:39, Bruce Kellett <mailto:bhkell...@optusnet.com.au>> wrote: 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 s

Re: Reversing time = local reversal of thermodynamic arrows?

On 11 November 2014 13:39, Bruce Kellett wrote: > > 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 >

Re: Reversing time = local reversal of thermodynamic arrows?

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

Re: Reversing time = local reversal of thermodynamic arrows?

e 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 sou

Re: Reversing time = local reversal of thermodynamic arrows?

OT 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 cov

Re: Reversing time = local reversal of thermodynamic arrows?

ng 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? The 2nd law is emergent, as I think we all agree, and

Re: Reversing time = local reversal of thermodynamic arrows?

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, inclu

Re: Reversing time = local reversal of thermodynamic arrows?

OK, so are you saying that the formation of bound states like nucleons has no bearing on the existence of an AOT? -- 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

Re: Reversing time = local reversal of thermodynamic arrows?

LizR wrote: On 10 November 2014 16:01, Bruce Kellett > wrote: LizR wrote: On 8 November 2014 16:53, John Clark mailto:johnkcl...@gmail.com> >> wrote: On Thu, Nov 6, 2014

Re: Reversing time = local reversal of thermodynamic arrows?

es out. Isn't that how inflation is used to explain the CMB uniformity? Yes, but that is not the argument Liz is making. and it probably will not be until all matter has collapsed into black holes and these have decayed by Hawking radiation. At any finite time, one useful concept of m

Re: Reversing time = local reversal of thermodynamic arrows?

On 10 November 2014 16:01, Bruce Kellett wrote: > LizR wrote: > >> On 8 November 2014 16:53, John Clark > johnkcl...@gmail.com>> wrote: >> >> On Thu, Nov 6, 2014 at 3:56 PM, meekerdb > > wrote: >> >> > I'd say that expansion of the universe is almost

Re: Reversing time = local reversal of thermodynamic arrows?

that how inflation is used to explain the CMB uniformity? and it probably will not be until all matter has collapsed into black holes and these have decayed by Hawking radiation. At any finite time, one useful concept of maximum entropy is to consider the state in which all mass energy is

Re: Reversing time = local reversal of thermodynamic arrows?

ailable degrees of freedom are in thermal equilibrium, then the universe has never been in such a state of maximum entropy, and it probably will not be until all matter has collapsed into black holes and these have decayed by Hawking radiation. At any finite time, one useful concept of maximu

Re: Reversing time = local reversal of thermodynamic arrows?

..@optusnet.com.au>>> 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 o

Re: Reversing time = local reversal of thermodynamic arrows?

On 10 November 2014 02:30, Stephen Paul King wrote: > Hi Alberto, > >you wrote: "There must not be a general arrow of time since time in > general relativity is local not only in his value but also its direction > AFAIK" > >Exactly! Time can be shown to

Re: Reversing time = local reversal of thermodynamic arrows?

On 08 Nov 2014, at 22:46, John Clark wrote: On Sat, Nov 8, 2014 Alberto G. Corona wrote: > The arrow of time is defined by the increase of entropy No, increasing entropy is not sufficient to establish a arrow of time, as I've said it can explain why Entropy will be higher tomo

Re: Reversing time = local reversal of thermodynamic arrows?

Hi Alberto, you wrote: "There must not be a general arrow of time since time in general relativity is local not only in his value but also its direction AFAIK" Exactly! Time can be shown to be local for QM systems as well. So, where does the illusion of a global dimensional time

Re: Reversing time = local reversal of thermodynamic arrows?

Hi LizR, Interesting! On Sun, Nov 9, 2014 at 3:11 AM, LizR wrote: > On 9 November 2014 14:25, Stephen Paul King wrote: > >> Hi Alberto, >> >>Is there really a global thermodynamic arrow of time? We can only >> infer its existence based on theoretical

Re: Reversing time = local reversal of thermodynamic arrows?

Hi Stephen: There must not be a general arrow of time since time in general relativity is local not only in his value but also its direction AFAIK 2014-11-09 2:25 GMT+01:00 Stephen Paul King : > Hi Alberto, > >Is there really a global thermodynamic arrow of time? We can only in

Re: Reversing time = local reversal of thermodynamic arrows?

On 9 November 2014 14:25, Stephen Paul King wrote: > Hi Alberto, > >Is there really a global thermodynamic arrow of time? We can only infer > its existence based on theoretical organizations of data that we collect. > AFAIK, all "arrows" in actual physical dynami

Re: Reversing time = local reversal of thermodynamic arrows?

Hi Alberto, Is there really a global thermodynamic arrow of time? We can only infer its existence based on theoretical organizations of data that we collect. AFAIK, all "arrows" in actual physical dynamics are local. On Friday, November 7, 2014 5:26:40 PM UTC-5, Alberto G.Co

Re: Reversing time = local reversal of thermodynamic arrows?

Most of the questions are explained in the presentation linked in the text 2014-11-08 22:46 GMT+01:00 John Clark : > On Sat, Nov 8, 2014 Alberto G. Corona wrote: > > > The arrow of time is defined by the increase of entropy >> > > No, increasing entropy is not suffici

Re: Reversing time = local reversal of thermodynamic arrows?

On Sat, Nov 8, 2014 Alberto G. Corona wrote: > The arrow of time is defined by the increase of entropy > No, increasing entropy is not sufficient to establish a arrow of time, as I've said it can explain why Entropy will be higher tomorrow but by using the exact same logic Entropy

Re: Reversing time = local reversal of thermodynamic arrows?

On 9 November 2014 06:36, John Clark wrote: > > On Fri, Nov 7, 2014 at 11:14 PM, LizR wrote: > > >> > The universe could potentially start in a state of maximum entropy (at >> least in terms of the equilibrium of mass-energy) >> > > That just means everything is at the same temperature, but that

Re: Reversing time = local reversal of thermodynamic arrows?

>If instead in the first instant of time the universe was in a very high >entropy state then in the second instant Entropy could have been >smaller or larger with about equal probability and there would be no >second law of thermodynamics and time would have no arrow. > I say &

Re: Reversing time = local reversal of thermodynamic arrows?

On Fri, Nov 7, 2014 at 11:14 PM, LizR wrote: > > The universe could potentially start in a state of maximum entropy (at > least in terms of the equilibrium of mass-energy) > That just means everything is at the same temperature, but that's not the only thing that determines Entropy. > and stil

Re: Reversing time = local reversal of thermodynamic arrows?

en volume). > > > The AoT has to point in the direction of entropy increase >> > > But the question is WHY does time point in the direction of entropy > increase. The answer is because in the first instant of time the universe > was in a extraordinarily low entropy state

Re: Reversing time = local reversal of thermodynamic arrows?

On 8 November 2014 11:40, Bruce Kellett wrote: > LizR wrote: > >> On 7 November 2014 22:30, Bruce Kellett > <mailto:bhkell...@optusnet.com.au>> wrote: >> >> No, my main problem with identifying the expansion of the universe >> as the origin of

Re: Reversing time = local reversal of thermodynamic arrows?

On 8 November 2014 11:26, Alberto G. Corona wrote: > if time is the thermodynamic arrow then then is meaningless the notion of > reversal of termodinamic arrow. > > In which time the termodinamic arrow is reversed? Does it mean that the > time goes forward while termodinamic arro

Re: Reversing time = local reversal of thermodynamic arrows?

e or imagination in the history of science. > The AoT has to point in the direction of entropy increase > But the question is WHY does time point in the direction of entropy increase. The answer is because in the first instant of time the universe was in a extraordinarily low entropy sta

Re: Reversing time = local reversal of thermodynamic arrows?

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 phenomen

Re: Reversing time = local reversal of thermodynamic arrows?

LizR wrote: On 7 November 2014 22:30, Bruce Kellett <mailto:bhkell...@optusnet.com.au>> 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

Re: Reversing time = local reversal of thermodynamic arrows?

On Friday, November 7, 2014 10:10:45 PM UTC, Bruce wrote: > > LizR wrote: > > On 7 November 2014 20:22, Bruce Kellett > > > wrote: > > > > You seem determined to play the role of 'spoiler' in this > > discussion, regardless of the merit of the argum

Re: Reversing time = local reversal of thermodynamic arrows?

if time is the thermodynamic arrow then then is meaningless the notion of reversal of termodinamic arrow. In which time the termodinamic arrow is reversed? Does it mean that the time goes forward while termodinamic arrow goes backward? that contradict the first assumption!!! 2014-10-15 2:14

Re: Reversing time = local reversal of thermodynamic arrows?

On 7 November 2014 21:07, Bruce Kellett wrote: > LizR wrote: > >> SO the AoT comes from the statistics of increasing entropy and is >> quite disjoint from the expansion of the universe. >> >> Bruce, I haven't got time to reply at length but one thing

Re: Reversing time = local reversal of thermodynamic arrows?

LizR wrote: On 7 November 2014 20:22, Bruce Kellett > wrote: You seem determined to play the role of 'spoiler' in this discussion, regardless of the merit of the arguments. ;-) Bruce, meet Brent! I have known Brent for many years on the avoid list. S

Re: Reversing time = local reversal of thermodynamic arrows?

On 7 November 2014 20:22, Bruce Kellett wrote: > You seem determined to play the role of 'spoiler' in this discussion, > regardless of the merit of the arguments. ;-) Bruce, meet Brent! -- You received this message because you are subscribed to the Google Groups "Everything List" group. To u

Re: Reversing time = local reversal of thermodynamic arrows?

. This means an expanding universe can never reach a state of equilibrium - this is particularly clear during the BB fireball, which I would say is very near to equilibrium for a lot of the time.) I thought I remembered that someone had written that the idea that the expansion produces more

Re: Reversing time = local reversal of thermodynamic arrows?

:02 AM, LizR wrote: > On 7 November 2014 22:30, Bruce Kellett 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 physic

Re: Reversing time = local reversal of thermodynamic arrows?

On 7 November 2014 22:30, Bruce Kellett 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

Re: Reversing time = local reversal of thermodynamic arrows?

On Friday, November 7, 2014 2:53:28 AM UTC, Brent wrote: > > On 11/6/2014 5:59 PM, Bruce Kellett wrote: > > LizR wrote: > >> On 7 November 2014 12:32, Bruce Kellett > >> > wrote: > >> > >> I have not seen your arguments for this, being new to the list,

Re: Reversing time = local reversal of thermodynamic arrows?

n expanding universe can never reach a > > state of equilibrium - this is particularly clear during the BB > > fireball, which I would say is very near to equilibrium for a lot of the > > time.) > > > I thought I remembered that someone had written that the idea that the

Re: Reversing time = local reversal of thermodynamic arrows?

e 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

Re: Reversing time = local reversal of thermodynamic arrows?

LizR wrote: SO the AoT comes from the statistics of increasing entropy and is quite disjoint from the expansion of the universe. Bruce, I haven't got time to reply at length but one thing stands out. You have said a few times that the AOT derives from the 2nd law / incre

Re: Reversing time = local reversal of thermodynamic arrows?

SO the AoT comes from the statistics of increasing entropy and is quite disjoint from the expansion of the universe. Bruce, I haven't got time to reply at length but one thing stands out. You have said a few times that the AOT derives from the 2nd law / increasing entropy. That is however

Re: Reversing time = local reversal of thermodynamic arrows?

expanding universe can never reach a state of equilibrium - this is particularly clear during the BB fireball, which I would say is very near to equilibrium for a lot of the time.) I thought I remembered that someone had written that the idea that the expansion produces more states so the entropy

Re: Reversing time = local reversal of thermodynamic arrows?

equilibrium - this is particularly clear during the BB fireball, which I would say is very near to equilibrium for a lot of the time.) I thought I remembered that someone had written that the idea that the expansion produces more states so the entropy ceiling increases with the expansion of

Re: Reversing time = local reversal of thermodynamic arrows?

hese states might not be quantum mechanically distinguishable, given the HUP, but the states exist, and eventually become distinguishable as space-time expands. There is also the question of Louiville's theorem -- the volume of any cloud of points moving through phase space remains constant s

Re: Reversing time = local reversal of thermodynamic arrows?

e one, because the two cancel out, so anthropically we find ourselves in a U with Dark Energy. (Just a thought.) I don't think that makes much sense -- how can arrows-of-time cancel out? Well, from a GR perspective an AOT is a constraint on the world lines of

Re: Reversing time = local reversal of thermodynamic arrows?

is particularly clear during the BB fireball, which I would say is very near to equilibrium for a lot of the time.) I thought I remembered that someone had written that the idea that the expansion produces more states so the entropy ceiling increases with the expansion of the universe is

Re: Reversing time = local reversal of thermodynamic arrows?

then the number of possible states is infinite, even for finite volumes. Unless Bekenstein's bound applies. These states might not be quantum mechanically distinguishable, given the HUP, but the states exist, and eventually become distinguishable as space-time expands. There is also the

Re: Reversing time = local reversal of thermodynamic arrows?

fireball, which I would say is very near to equilibrium for a lot of the time.) I thought I remembered that someone had written that the idea that the expansion produces more states so the entropy ceiling increases with the expansion of the universe is mistaken. I have found the reference, it is

Re: Reversing time = local reversal of thermodynamic arrows?

not go too far as it becomes a shaggy dog story of bollocks that terminates in rant about deutsch The word Carry...that was about disputing gravity is explained by space time in a substantial sense better. I want your help with this. But I don't think I'm sufficiently clear what my m

Re: Reversing time = local reversal of thermodynamic arrows?

of locality. Are there any favorite definitions of "locality" out there? AFAIK, it does not have a fixed size in space, but may have a fixed size in "space-time" as location information expands at the speed of light if we ignore the effects of local

Re: Reversing time = local reversal of thermodynamic arrows?

anthropically we find ourselves in a U with Dark Energy. (Just a thought.) I don't think that makes much sense -- how can arrows-of-time cancel out? Well, from a GR perspective an AOT is a constraint on the world lines of matter. If you put constraints on the entire contents

Re: Reversing time = local reversal of thermodynamic arrows?

e, even for finite volumes. These states might not be quantum mechanically distinguishable, given the HUP, but the states exist, and eventually become distinguishable as space-time expands. There is also the question of Louiville's theorem -- the volume of any cloud of points moving thr

Re: Reversing time = local reversal of thermodynamic arrows?

U with Dark Energy. (Just a thought.) >> > > I don't think that makes much sense -- how can arrows-of-time cancel out? Well, from a GR perspective an AOT is a constraint on the world lines of matter. If you put constraints on the entire contents of the universe at both ends of tim

Re: Reversing time = local reversal of thermodynamic arrows?

sition to answer that question, but certainly inflation (eternal or otherwise) naturally produces a very smooth background. But somewhat lumpy backgrounds should work. This is a question of the timescales involved, I imagine - the relaxation time of a volume of matter against the expansion time. I'

Re: Reversing time = local reversal of thermodynamic arrows?

n. Inhomogeneities arise at the end of inflation -- the post-inflation reheating is basically a quantum process so it does not occur at the same time everywhere. Exiting inflation at different times leads to inhomogeneities on all scales, and there is no reason to suppose that these are of

Re: Reversing time = local reversal of thermodynamic arrows?

On 11/6/2014 5:59 PM, Bruce Kellett wrote: LizR wrote: On 7 November 2014 12:32, Bruce Kellett > 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 relativit

Re: Reversing time = local reversal of thermodynamic arrows?

the total possible for a given volume, the entropy could increase whether the universe were actually expanding or contracting. Anything else and you are necessarily committed to a reversal of the arrow of time if the universe begins to re-contract at some point. This may be why the AOT

Re: Reversing time = local reversal of thermodynamic arrows?

if I assumed that the reversible >>> measurement idea is to be taken as a local reversal to the "direction of >>> entropy flow" in an area and not the entire universe. >>>The trouble is this notion of locality. Are there any favorite >>> definit

Re: Reversing time = local reversal of thermodynamic arrows?

LizR wrote: On 7 November 2014 12:32, Bruce Kellett > 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,

Re: Reversing time = local reversal of thermodynamic arrows?

Oops I seem to have cut off the end of this. Luckliy I wrote another reply anyway. Damn browser getting me all confused and stuff. On 7 November 2014 14:40, LizR wrote: > On 7 November 2014 12:32, Bruce Kellett wrote: > >> >> I have not seen your arguments for this, being new to the list, but t

Re: Reversing time = local reversal of thermodynamic arrows?

On 7 November 2014 14:27, Stephen Paul King wrote: > Hi Zibbsey, > >A new discovery for you. A computer can be a topological shape! A > sector of the structures that are invariant under dilations in > Sub-Riemannian manifolds is identical to the Lambda calculus. >This can be said to imply

Re: Reversing time = local reversal of thermodynamic arrows?

On 7 November 2014 12:32, Bruce Kellett 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 eve

Re: Reversing time = local reversal of thermodynamic arrows?

ot;). >>> >> >> I disagree. There is no necessary connection between the expansion and >> the increase in entropy. The total possible entropy might increase with >> expansion, but if we are always a long way below the total possible for a >> given volume,

Re: Reversing time = local reversal of thermodynamic arrows?

e with > expansion, but if we are always a long way below the total possible for a > given volume, the entropy could increase whether the universe were actually > expanding or contracting. Anything else and you are necessarily committed > to a reversal of the arrow of time if the universe be

Re: Reversing time = local reversal of thermodynamic arrows?

more sense than before if I assumed that the reversible >> measurement idea is to be taken as a local reversal to the "direction of >> entropy flow" in an area and not the entire universe. >>The trouble is this notion of locality. Are there any favorite >> de

Re: Reversing time = local reversal of thermodynamic arrows?

> > As I recall it, Vic later recanted his earlier idea that the AoT reversed > if the universe began to re-contract. > > I think that was Hawking. I think it was Gold who proposed the idea of a universe where the AOT reverses in contraction phase. It's a logical outcome of view that AOT derives

Re: Reversing time = local reversal of thermodynamic arrows?

py increase and >> in almost all models that's correlated to the expansion of the universe. >> If it is bigger at one time than at another then the AoT will point toward >> the bigger end. I say "almost" because there are some ways around it. If >> the univers

Re: Reversing time = local reversal of thermodynamic arrows?

tted to a reversal of the arrow of time if the universe begins to re-contract at some point. I concede it's possible, but I don't know of any model that corresponds to that. Brent -- You received this message because you are subscribed to the Google Groups "Everything List" g

Re: Reversing time = local reversal of thermodynamic arrows?

le entropy might increase with expansion, but if we are always a long way below the total possible for a given volume, the entropy could increase whether the universe were actually expanding or contracting. Anything else and you are necessarily committed to a reversal of the arrow of time if t

Re: Reversing time = local reversal of thermodynamic arrows?

the direction of entropy increase and in almost all models that's correlated to the expansion of the universe. If it is bigger at one time than at another then the AoT will point toward the bigger end. I say "almost" because there are some ways around it. If the uni

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