"Entropy" (1854 - 2021)

Jul 24, 2020
15
4
515
Rob Sheldon: “It From Bit” Is Winning The Cosmology Wars
Posted on September 21, 2021
----------------------
Ethan Siegel,
“Are we approaching quantum gravity all wrong?” at Big Think (September 16, 2021) -----
“gravity is emergent” from entropy that you can calculate based on the microscopic quantum state
of all the particles aggregated together.
Lee Smolin:"
the role of entropy in cosmological theory is something we have to get our heads straight about. “
Ethan :
“information” emerges from the particles . . . .
“entropy” or “information” emerges from the particles
Not only is “entropy” or “information” fundamental in the 21st century view of physics,
but in quantum information theory it is now held that “we wouldn’t say entropy is a property of a system,
but a property of an observer who describes a system.”,,,
Renato Renner, a professor ;
Fifteen years ago, “we thought of entropy as a property of a thermodynamic system,” . . .
“Now in (quantum) information theory, we wouldn’t say entropy is a property of a system,
but a property of an observer who describes a system.”,,,
“entropy is (not) a property of a system, but a property of an observer who describes a system.”
is with the quantum Zeno effect.
The reason why I am very impressed with the preceding experiments demonstrating that
“entropy is (not) a property of a system, but a property of an observer who describes a system”
is because entropy is very foundational in our scientific descriptions of the world.
As the following article states, “Entropy explains time; it explains every possible action in the universe;,,”,,
“Even gravity,,,, can be expressed as a consequence of the law of entropy.,,,”
Shining Light on Dark Energy – October 21, 2012
Excerpt: It (Entropy) explains time; it explains every possible action in the universe;,,
Even gravity can be expressed as a consequence of the law of entropy.,,,
The principles of thermodynamics are at their roots all to do with information theory.
Information theory is simply an embodiment of how we interact with the universe —,,,
Big bang by chance (?):
"The explosion in which our universe began was not a messy event." . . . .
And if you talk about how messy it could have been, this is what the Penrose calculation
is all about essentially. . . . This number has 10^123rd zeros.
Thus, considering entropy’s central importance in scientific explanation, (as well as in our own lives),
the statement “we wouldn’t say entropy is a property of a system, but a property of an observer
who describes a system.” is just fascinating!
===========
Where can "entropy" be used?
Entropy - in cosmological theory
Entropy - in quantum information theory
Entropy - is not only a property of a system, but also a property
of an observer who describes a system.
Entropy - can explain time
Entropy - can explain quantum gravity
Entropy - can explain every possible action in the universe
==========
John von Neumann said to the "father of information theory" Claude Shannon:
"Call it 'entropy', then in discussions you will get a solid advantage,
because no one knows what 'entropy' in general is."
------
"Entropy" (1854 - 2021)
==================
 

IG2007

"Don't criticize what you can't understand..."
Apr 5, 2020
727
833
1,760
Entropy is barely the amount of disorder in a closed heat system. Gravity cannot be attributed to entropy because it is a result of space-time curvature. :)
 
  • Like
Reactions: Catastrophe
Nov 20, 2019
393
218
1,060
Entropy - can it decrease (overall) if the Universe contracts? (As in cyclic scenarios).

Cat :)
I was hoping my post

https://forums.space.com/threads/dark-matter-vs-mond-vs-gravity-by-em-waves.47222/post-554768

would answer some questions about entropy. It seems to have been completely unnoticed. Maybe you thought the ideas were not good or maybe because I mentioned they were from my book I'm not sure which?

Anyway, have another look and see if it helps. I think it might relate to IG's post as well. :)
 
  • Like
Reactions: Catastrophe

Catastrophe

The devil is in the detail
David,
I have looked at your referenced post #4. In fact this idea has been around for some time, and I have used it in the cyclic Universe context. I was not the first to refer to it either by a long chalk.

Where I used it was not in the context of localised reduction in entropy in a small part of the Universe, but in total reduction in entropy necessary to go from the maximum extent of the Universe to a Black Hole to Big Bang occurrence between one phase of a (the) cyclic Universe and the next.

I totally agree with what you suggest about contraction of molecular clouds.

Cat :) :) :)
 
  • Like
Reactions: David-J-Franks
Nov 20, 2019
393
218
1,060
David,
I have looked at your referenced post #4. In fact this idea has been around for some time, and I have used it in the cyclic Universe context. I was not the first to refer to it either by a long chalk.

Where I used it was not in the context of localised reduction in entropy in a small part of the Universe, but in total reduction in entropy necessary to go from the maximum extent of the Universe to a Black Hole to Big Bang occurrence between one phase of a (the) cyclic Universe and the next.

I totally agree with what you suggest about contraction of molecular clouds.

Cat :) :) :)
If gravity can do it for molecular dust clouds ie nebula, then why can't it do it for a universe? it's the same principle. When gravity collapses something, it concentrates all the energy, all the matter and all the information and order all in one go.

By the way, did you mean to use an uppercase U for universe? In that case you can't speak of the Universe collapsing because it is probably infinite IMO. Only a local universe lower case u can collapse back into a black hole I think. You can't have the whole infinite Universe go through your nexus idea, it's too big it won't fit! :)
 
  • Like
Reactions: Catastrophe

Catastrophe

The devil is in the detail
First Universe. If it is the Universe going through phases separated by BH -> BB nexus, then I use U for the one Universe going through 'phases'.

The dust cloud is just a limited part of the Universe which is allowable in classical physical. What is "not allowed" is total reduction in entropy for the whole Universe.

BTW, you say the whole Universe will not go through a nexus. But, according to the BB, it all starts in a singularity.

Cat :)
 
  • Like
Reactions: David-J-Franks

Catastrophe

The devil is in the detail
David,
The problem with cyclic Universe is that entropy increases (overall) from BB to state of maximum expansion. Contraction is then required to get through a nexus to the next BH/BB. My question, which I have posed and nobody has answered, is how the entropy gets back to a low level before the next nexus. Entropy must decrease as the Universe gets more and more closely packed together - in analogy to crystallization.

If entropy keeps increasing, nexus after nexus, then the cyclic process cannot be sustained.

Cat :)

Added 00.15 BST:
"It just says that the total entropy of the universe can never decrease. Entropy can decrease somewhere, provided it increases somewhere else by at least as much. The entropy of a system decreases only when it interacts with some other system whose entropy increases in the process."
 
Last edited:
  • Like
Reactions: David-J-Franks
Nov 20, 2019
393
218
1,060
First Universe. If it is the Universe going through phases separated by BH -> BB nexus, then I use U for the one Universe going through 'phases'.

The dust cloud is just a limited part of the Universe which is allowable in classical physical. What is "not allowed" is total reduction in entropy for the whole Universe.

BTW, you say the whole Universe will not go through a nexus. But, according to the BB, it all starts in a singularity.

Cat :)
BTW, you say the whole Universe will not go through a nexus. But, according to the BB, it all starts in a singularity.
I think The Big Bang theory has done more damage and caused more confusion to science than anything else.

First is the singularity concept, this requires the there is a single infinitely small point with an infinite density. I find that completely stupid and unscientific, sorry, I know that statement is also unscientific but there you go.

Then - "according to the BB, it all starts". That's another nonsense because it is not known what 'all' is so no theory can say how it 'all' starts, it's a non starter to start with.

Then when people ask what is beyond the universe the experts quote that the universe created all of space so there is nothing beyond it. There's a similar response when people ask what was before The Big Bang and again the answer comes back there's nothing before because The Big Bang was the beginning. Again I find both these to be another nonsense. Stephen Hawking even solidified this thinking with his expression "it's like asking what's north of the North Pole".

My reason for thinking this is nonsense is as follows;

1. The big bang started from a hot dense patch, NOT a sngularity and so started with a finite size.

2. It's undergone finites rates of expansion

3. It has a finite age.

I suggest all of which means it has a finite size now, and so is an object. Objects exist in a space, they do not create all of space as the BB theory suggests. If space consists of 'something', then the BB may well have created its own internal space, but at the same time it must have existed in a pre-existing space, the Universe.

I suggest the big bang was the beginning of our local finite sized universe and not the infinite Universe.

For me the next line of thinking is, is there only our one finite universe sitting in an otherwise infinite emty space or, is space full of an infinite number of other finite universes? It's easy to understand an infinite number but you would have a very hard time explaining why there would be only one. Even more strange why you would only get one undergoing a cyclic process on its own forever in the middle of nowhere!

If you agree with my line of thinking then, IMO, you cannot have an infinite ( anyone care to dispute that) Universe which contains my suggested infinite universes, become a black hole and then go through a nexus. It's too big, it wont fit. I suggest your idea works well if you have just finite universes going through a nexus.

The final nonsense for me is the indefinite expansion of our universe, that is, the heat death of our universe. Again, with my above line of thinking our universe will stop expanding when it hits some of the other universes in the rest of the Universe.

Sorry, not the final nonsense, the final one is that the BB theory says there's no center or edge to our universe. However it's clear from my suggestion of our universe being a finite object, that it does have a center and an edge!

Back to the dust cloud. If gravity can do it for molecular dust clouds ie nebula, then why can't it do it for a finite universe or universe size clump of something? it's exactly the same principle. When gravity collapses something, it concentrates all the energy, all the matter and all the information and order all in one go. The difference with my thinking is that it's not the whole infinite Universe collapsing, which would be nonsense. :)
 
  • Like
Reactions: Catastrophe
Nov 20, 2019
393
218
1,060
David,
The problem with cyclic Universe is that entropy increases (overall) from BB to state of maximum expansion. Contraction is then required to get through a nexus to the next BH/BB. My question, which I have posed and nobody has answered, is how the entropy gets back to a low level before the next nexus. Entropy must decrease as the Universe gets more and more closely packed together - in analogy to crystallization.

If entropy keeps increasing, nexus after nexus, then the cyclic process cannot be sustained.

Cat :)

Added 00.15 BST:
"It just says that the total entropy of the universe can never decrease. Entropy can decrease somewhere, provided it increases somewhere else by at least as much. The entropy of a system decreases only when it interacts with some other system whose entropy increases in the process."
My question, which I have posed and nobody has answered, is how the entropy gets back to a low level before the next nexus.
I've answered it several times in these forums with my dust cloud analogy.
Entropy must decrease as the Universe gets more and more closely packed together - in analogy to crystallization.

If entropy keeps increasing, nexus after nexus, then the cyclic process cannot be sustained.
You said it, it must work, it's part and parcel of your cyclic theory.

The fact that after an infinite time there is still some low enropy left proves there must be a mechanism to reset it to a lower level. After an infinite time no overall heat death has occurred because we are here. That means it never will occur!:)
 
  • Like
Reactions: Catastrophe

Catastrophe

The devil is in the detail
David,
"I think The Big Bang theory has done more damage and caused more confusion to science than anything else.

First is the singularity concept, this requires the there is a single infinitely small point with an infinite density. I find that completely stupid and unscientific, sorry, I know that statement is also unscientific but there you go."

On this we are totally agreed, If I could agree (much, much more) than than 100%, I would. It is openly admitted that division by zero steps outside the bounds of science and, therefore, that the singularity concept is unscientific.

I have to disagree about the Universe / universes issue, on which I have made my ideas clear on (many) more than one occasion. The terminology needs correcting before a sane discussion is possible. Some new word is necessary to get around this. I do not hold out much hope, since 'multiverses' seems too strongly entrenched to correct. I shall just have to accept that I will not live to see it changed, and leave it alone to fester.

Anyway, I am pleased that we agree on the (pseudo) BB and singularity issues.

Cat :) :) :)
 
  • Like
Reactions: David-J-Franks
Aug 14, 2020
421
89
760
"Yet the thought has many times occurred to me, how many and how great are the benefits which accrue to states through History, which transmits to future generations the memory of those who have gone before, and resists the steady effort of time to bury events in oblivion...." -- Procopius, 'Buildings', Book I, Chapter I.
 

ASK THE COMMUNITY