How may entropy be reversed?

[BlueCosmology]

This point of view and its based on a incomplete view of the universe. The perspective we see is based on a conic section of 3.55' off a radial from the center to our position in space that ends before the edge of the material universe along that radial. Give the estimated size and our age of the universe. The isoquant we see is 0.25% or less of all possible isoquants and thus we are traveling away from most points in our universe very close to the speed of light. It is not possible to see the center or edge from this perspective, does not imply that neither exist. The CMB you see, as isotropic as it appears does not represent the afterglow of the entire universe as some would imply, just the comoving space close to the where our galaxies matter finally materialized. There is an assumption that any point in space would have the same perspective as our perspective, but that is just an assumption. I love astrophysics, it is so full of BS.

I look forward to hearing about your nobel prize. (you might like to make sure in your acceptance speech though you look up what field you're actually talking about. The topology of the universe is cosmology not astrophysics)

[KSK]

That is the point, but the point had no momentum in any recognizable form (either collectively or discrete), thus it could be anywhere. When inflation ends and the forces unravel then momentum appears, but can you directly connect that momentum back to a reaction at the center of inflation? no, its connected to something that is meaningless in our space-time.

I don't understand what you're trying to say here. If I'm understanding K-2 correctly the point you refer to is a point within a mathematical n-dimensional space used to describe the classical system he was talking about. The n-dimensional space and the points within it aren't real - they're just a convenient tool used to describe a real system. Therefore talking about the momentum of the point is meaningless.

[PB666]

I don't understand what you're trying to say here. If I'm understanding K-2 correctly the point you refer to is a point within a mathematical n-dimensional space used to describe the classical system he was talking about. The n-dimensional space and the points within it aren't real - they're just a convenient tool used to describe a real system. Therefore talking about the momentum of the point is meaningless.

'aren't real' - no duh. But that inflation has to end and at the moment it ends the transition will dump huge amounts of energy but a hell of alot of differential momentum. Its very easy to argue that if this is the end of our observation (backward in time), and assumes that the space itself expanded, but this is not proven. In fact inflation itself is a convenient way to explain the relative motion of galactic clusters in our visible universe (the fact that everything is moving away and not swirling away as might be expected from an expansion), but we also have to wary that convenient explanations may not be entirely correct.

[WinkAllKerb'']

what if the distance between two universes is like the distance between two galaxy, like the distance between two atom somehow ? *just a though anyway*

[PB666]

I look forward to hearing about your nobel prize. (you might like to make sure in your acceptance speech though you look up what field you're actually talking about. The topology of the universe is cosmology not astrophysics)

You mean to say you practice a form of idolatry, which is your choice; I for one place no stock in the nobel prize or anyone who has one. I forgot to add, the 2003 paper describes the minimum size of the entire universe, not the visible universe. What it means is that if the universe were smaller at some point we would see duplicitous patterns in the CMB, but since these are not observed the minimum size must be larger. Your basic argument follows:

Premise 1: If I look out on the universe (visible), all that is seen is moving away from all else that I see at a rate consistent with distance

Conclusion 1: therefore all points in the universe are the same in every regard.

I respond to this:

Assumption 1: That you can see to all the points or at least a fair representation of all the points.

Disproof 1: You are too far from the edge and your ancestral 'space' was to far from the edge to see edge points (2003 paper). That light has not yet reached us.

Counter-proposal 1: The cross-sectional topology of the visible is sampling from an expanding platykurtotic distribution the larger the space around us and the faster things inflated/expanded before the first stars formed the more uniform that universe will look to us today. But it also means that there are places in the topology where the broad plateau gives way to a transitional edge. There are thoughts about this, one of the thoughts is that if universe was too large it would not expand outward forever, and begin to collapse on itself. The appearance of dark energy as a requirement for current inflation seems to imply that argument has been complicated, or mass maximally is not sufficient to overcome dark energies contribution. There are two of three possibilities. 1. we are at dead center, 2. we are at the edge (disproven) 3. we are traveling along a radial from the center outward (4. that somehow mulitverses are involved and we are only a radial in a local bubble), given the 2003 paper 3 (or 4) is by far the most likely probability and in addition, all the visible universe that we see is also moving away along their own radials.

Assumption 2: Space expanded is concordant with energy expansion.

Refutation 2: Since it is currently impossible to see past the opaque period, and since the expansion of space is set forth at the end of inflation or before, claiming of when and how space inflated/expanded is speculation and based in theory and hypothesis and not observable past events. Numerous scientist have made this same statement, nothing new.

The reason inflation was added was to explain the 'flatness' of the Universe, but since the CMB originates much closer to the space-time origins of the Universe, it also helps to explain this also. The recent claim that there were detectable anisotropies in the CMB have been disproven, which means to me that the inflated bubble must have been quite large and that we are only seeing a very tiny portion of the Universe, and this also helps to explain it 'flatness'. However, don't imply that the universe is curled over supervisible space, the universe appears to exhibit Euclidian flatness and I see no reason that it should curl.

[WinkAllKerb'']

blablabla big molecule moving slowly, but i live 0-130 i just can't understand why time doesn't matter ... don't scale always to "yourself'hi f'hive in the iphone eve apple peal mirror" so boring ...

Edited March 4, 2015 by WinkAllKerb''

[Mr Shifty]

The CMB you see, as isotropic as it appears does not represent the afterglow of the entire universe as some would imply, just the comoving space close to the where our galaxies matter finally materialized. There is an assumption that any point in space would have the same perspective as our perspective, but that is just an assumption. I love astrophysics, it is so full of BS.

1. The CMB we observe isn't isotropic. It has a measurable polarity due to our galaxy's movement relative to the cosmic rest frame.
   
2. Even if what you propose is accurate, why does it matter? All we can observe is our Hubble sphere, and it doesn't matter at all what happens outside it.
   
3. I think you're conflating inflation and cosmic expansion. Inflation is the theory of rapid exponential expansion in the first instants after the big bang. It provides a possible explanation for the CMB isotropy (over distances that shouldn't be able to affect each other), the observed flatness of space time, and the lack of magnetic monopoles. Cosmic expansion is the continued 'slow' expansion of space time, due to which we observe red shifts in distant galaxies. They're two different theories to explain two different sets of observations. Inflation, as far as I can tell, always refers to the former, not the latter.
   

[KSK]

Prosaically, if it's a fluid you can lower the object's pressure (i.e. make it do work); its average temperature will decrease without transferring heat anywhere. Or you could melt ice, which uses up energy without raising temperature. More esoterically, you could maybe cause large nuclei to fuse, using up heat energy for atomic binding.

Formally (at least according to Wikipedia - my thermodynamics is distinctly rusty): "heat is energy in transfer other than as work or by transfer of matter. When there is a suitable physical pathway, heat flows from a hotter body to a colder one."

So to transfer heat to the ice, the object you're transferring heat from would need to be hotter than the ice. Likewise, for the fusing nuclei, the object you're transferring heat from would need to be hotter than the temperature at which your nuclei fuse.

Back on topic for entropy, I found this interesting looking page. It's pretty maths heavy, and I'd be interested in hearing what K-2 or another of our more mathematically inclined posters makes of it before jumping to any conclusions about its validity. However I thought the introduction was quite relevant to this thread:

"Entropy is ubiquitous in physics, and it plays important roles in numerous other disciplines ranging from logic and statistics to biology and economics. However, a closer look reveals a complicated picture: entropy is defined differently in different contexts, and even within the same domain different notions of entropy are at work. Some of these are defined in terms of probabilities, others are not."

So unless we can agree on what kind of entropy we're talking about, it's going to be a jumbled debate at best.

[ZetaX]

So unless we can agree on what kind of entropy we're talking about, it's going to be a jumbled debate at best.

We are talking about the ones from (quantum) physics, most prominently thermodynamics. The others are abstract measures of abstract things: e.g. the entropy from coding theory (informatics, mostly) measures how much information a given message contains (which can be very different form its length). Any physical system, closed or not, is not a message by itself, so this cannot apply. Similiar for the other ones.

[PB666]

This thread isn't dead yet, curious.

Maybe I can blow it up then. Physics can explain the movement of energy everywhere, but it cannot explain everything, it gets back to CMBR.

So therefore it assumes how energy moved before CMBR.

It is plausible that the direction of matter and energy was reversed prior to the CMBR and that everything compressed and the laws of physics - reversed, again and it expanded.

During the reversal process, the speed of light was not longer a barrier, but once complete our universes physics took, no-one else the wiser.

Entropy is a measure of disorder, its sort of like a childs bed-room (or my sisters some people never grow up). Once the room reaches a certain level of disorder its not longer functional as a room, and someone; hopefully the child, cleans the room up. Then the room begins the process over again.

The first process has been philosophically called Heat Death of the Universe.

Thats right, not only philosophy but medieval and renaisannce philosophy, from the ranks of Occam and the like.

All that radiation poured away into the vacuum of space particles spread so far apart they ceased to gravitationally interact or even be notice, naer to be seen again. Everything that can decay has decayed and everthing else is infinitely stable. Even blacks holes fail to emmit x-rays. So either the Universe goes into the Death State (which includes not debating the state of the Universe on a animated space game web forum) or it reverses itself and heads back to a state of complete cosmic annihilation. There is the concept that vacuum space expanded in advance of cosmic expansion, this advance may be what drives disorder. It might be possible that vacuum space contracts, and brings all space, matter, light and everything back with it. The contraction of vacuum space drive reordering the universe. We may find ourselves living the lives of Merlin.

[Technical Ben]

To replay to the question in the OP, some would say "wait long enough" but I doubt that's a proven theory.

Entropy cannot be reversed from within, it would have to be done outside. So when talking about "the entropy of my sandwich" I can add energy or reverse it['s entropy, but it cannot do so it's self. If we expanse "sandwich" to the "universe", we have nothing left inside to add energy to the system.

Then it depends on our definition of "universe" as to what could or could not exist "outside" it to reverse entropy.

[mcart1985]

No question is unsolvable in all conceivable circumstances.

If a question cannot be answered then one simply does not have all the information required. With our current understanding of the laws of physics it is impossible for us to even present a factual answer to this question. We as of yet, Have not gained enough information. We can theorise. In theory it is both possible and impossible to reverse entropy. It is indeed possible that the answer cannot be truly answered unless information is collected over hundreds of billions of years and then is only analysed after there is no more information to be gained such as how the Cosmic AC done it in the Last Question to which this is reference

[Bill Phil]

It's likely that at any time, a pocket of the universe could randomly lower in entropy. Like matter and energy, it's impossible for their to be uniform density.