Entropy of Static and Perpetually Old Universe

[coldcreation]

 

Things change. Stuff evolves, often very slowly.

 

In derogation of the 2nd principle of thermodynamics?

 

Things change in conjunction with the second law.

 

Hawking's almost laughable quote above is based on a meaningless, outdated concept of entropy: that of Clausius, Boltzman, Helmholtz and Gibbs (as the disorder of a system).

 

See here, for a contemporary interpretation of entropy which states the second law as follows: "Energy of all types changes from being localized to becoming more spread out, dispersed in space if that energy is not constrained from doing so". It so happens that gravity, along with other so-called forces of nature may constrain energy from becoming more spread out or dispersed in space.

 

"Entropy measures the spontaneous dispersal of energy: how much energy is spread out in a process, or how widely spread out it becomes — at a specific temperature."

 

 

See too:

 

Entropy is not “disorder”

Entropy change measures the dispersal of energy (at a specific temperature), i.e. qrev/T

 

 

 

This line of reasoning is entirely fallacious. It assumes that things in an infinite spatiotemporal universe have been here forever.

 

The first law of thermodynamics would assert that.

 

~modest

 

Not at all modest. The first law states that energy can be transformed, changed from one form to another. This process is often (perhaps even always) a continuous process.

 

So Hawking's conclusion that "the universe can have been going only for a finite time" or "the universe would by now have degenerated into a state of complete disorder, in which everything would be at the same temperature" is simply near-sighted and unsupported by both empirical evidence and our contemporary understanding of well-established physical laws: particularly those of quantum mechanics, electromagnetism, general relativity and statistical mechanics.

 

 

 

CC

[modest]

This line of reasoning is entirely fallacious. It assumes that things in an infinite spatiotemporal universe have been here forever.

 

The first law of thermodynamics would assert that.

 

~modest

 

Not at all modest.

 

Yes. It really does assert that.

 

The first law states that energy can be transformed, changed from one form to another.

 

That's fine. It still would need to have "been here forever" under your predicates and conservation laws. The "evolution" and "transformations" you're talking about would still need to follow the second law, so the objection to a static and perpetually old universe would seem to stand.

 

Also, let me just reassert: there are solutions to this problem. Hoyle solved the problem in his perpetually-old model by breaking the first law explicitly. I'm ok with that, but we should say clearly that's what needs done.

 

~modest

[coldcreation]

Yes. It really does assert that.

 

Limiting the discussion to thermodynamics would be to limit the scope of possibilities. Gravity plays the central role when it comes to the evolution of the universe. The first law simply states that energy can be transformed from one form to another. The second law simply states that energy is dispersed in space. Gravity tends to prevent energy (in the form of matter) from doing so. Certainly, energy in the form of radiation is dispersed; perhaps resulting in the CMBR.

 

The point is, the evolution of the universe is not entirely based upon thermodynamics (far from it), and so to rule out a cosmology based on thermodynamics is a perilous affair. That would especially be true in the case of a universe that has been here for an infinite amount of time. The issue is far to complex for that.

 

For example if a static universe model (one that has no beginning or end) were to claim that the universe evolved from the ground state up, i.e., from zero-point energy fluctuations to that which is observed tonight, there is nowhere in its history where (or when) the laws of thermodynamics are violated. Energy is transformed in accord with the first law. Entropy increases with time, as stars emit radiation, in accord with the second law. And since entropy is determined only by the degeneracy of the ground state, the evolution of such a universe would be consistent with the third law as well.

 

Finally, to top everything off, gravity would, throughout the entire process be operational, doing what it does best.

 

The bottom line (and excuse the above simplification) is that a static infinite spatiotemporal universe (of the type you call perpetually old) evolves dynamically and continually entirely in accord with thermodynamics. And it does so despite what Hawking writes to the contrary.

 

 

 

That's fine. It still would need to have "been here forever" under your predicates and conservation laws. The "evolution" and "transformations" you're talking about would still need to follow the second law, so the objection to a static and perpetually old universe would seem to stand.

 

The objection to a static and perpetually old universe on the grounds that the laws of thermodynamic are violated stands on nothing but a misinterpretation of thermodynamics adapted to the universe as a system within itself, to the exclusion of gravity.

 

 

Also, let me just reassert: there are solutions to this problem. Hoyle solved the problem in his perpetually-old model by breaking the first law explicitly. I'm ok with that, but we should say clearly that's what needs done.

 

As Hoyle pointed out, the continuous creation of matter⎯via the "C-field", short for creation field: a type of scalar field that would create new matter and carry negative pressure⎯is no worse than having it all pop out at once.

 

There is no reason why the first law (or any other law) needs to be broken, within the framework of a static model. All one needs to do is replace the concept of continuous creation of matter, with the continuous transformation of energy. And obviously, the nondecrease of entropy (or the second law of thermodynamics, if you will) is placed in check by the infamous gravitational interaction.

 

That's the short story, as you can imagine. :)

 

 

CC

[Qfwfq]

Hawking's almost laughable quote above is based on a meaningless, outdated concept of entropy: that of Clausius, Boltzman, Helmholtz and Gibbs (as the disorder of a system).

 

See here, for a contemporary interpretation of entropy which states the second law as follows:

That's the same concept of entropy, it can't reach distinct conclusions.

 

This is a bit cryptic, or at least I can't figure out what you refer to, can you elaborate on it?

Olbers' Paradox

 

See the paragraph that mentions points 4 and 5, near the end. If it weren't for the matter of age, the CMB could be due to redshifted radiation from distant galaxies.

[quantumtopology]

If it weren't for the matter of age, the CMB could be due to redshifted radiation from distant galaxies.

But that is exactly what I'm saying, the CMB can be due to just that in a universe infinite in time and space.

[coldcreation]

 

Olbers' Paradox

 

See the paragraph that mentions points 4 and 5, near the end. If it weren't for the matter of age, the CMB could be due to redshifted radiation from distant galaxies.

 

All that is needed to resolve Olbers' paradox is (1) an infinite universe that is sufficiently non-Euclidean, or (2) an infinite universe where galaxies have not been in existence forever. Any combination of the two will equally resolve the issue.

 

In other words, a universe where redshift is due to curvature solves the paradox, just as expansion.

 

An infinite universe where galaxies are formed and evolve with time can have an epoch before which galaxies existed, just as a finite universe has an epoch before which galaxies existed. Judging from the age of stellar components both solutions solve the paradox equally well.

 

 

CC

[Qfwfq]

In other words, a universe where redshift is due to curvature solves the paradox, just as expansion.

Due to curvature without expansion, with what kind of metric? :(

[coldcreation]

Due to the off-topic nature of the redshift-curvature relation, I've moved the response to Qfwfq to the appropriate thread: this one.

[quantumtopology]

Edited due to error

[Qfwfq]

Right, so how does it give rise to redshift?

[quantumtopology]

Right, so how does it give rise to redshift?

 

As I tried to explain in several posts in a hyperbolic space radiation redshifts as a function of distance, the simple explanation is that in a hyperbolic space we observe with "euclidean eyes" the light from distant objects that follows a hyperbolic path, the conformal projection of light geodesics in a hyperbolic space to our Euclidean frame of observation produces this sort of distortion that is perceived as a stretching of wavelength with respect to the original theoric wavelength of the spectrum at the source point.

This is quite straight-forward if we apply hyperbolic geometry to EM waves, the only assumptio one has to make is that the universe is spatially hyperbolic, and this is not so crazy, until 1998 it was a seriously considered possibility by mainstream cosmology.

 

Ironically, the SNIa surprise (Perlmutter 1999) that is actually a signature of hyperbolic space (in hyperbolic space you must observe that non-linear departure in magnitude/redshift relation for geometrical reasons), made the mainstream cosmologists opt for the flat universe in order to salvage the CDM model, they called it accelerated expansion, attributed to "dark energy" and ever since the L-CDM model rules.

 

 

Regards

Qtop

[modest]

There is no reason why the first law (or any other law) needs to be broken, within the framework of a static model. All one needs to do is replace the concept of continuous creation of matter, with the continuous transformation of energy. And obviously, the nondecrease of entropy (or the second law of thermodynamics, if you will) is placed in check by the infamous gravitational interaction.

 

That's the short story, as you can imagine. :shrug:

 

It sounds to me like you are describing a perpetual motion machine. How would you describe the complete history of a galaxy in our universe?

 

~modest