Split Thread Michael Mozina's thread on Dark Matter, Inflation and Cosmology

[Tubbythin]

No. If there are no carrier particles of the EM field hitting the inside or the outside of the plates, there will simply be no "pressure" difference between the outside or the inside of the plates.

The Casimir effect is not the effect or real photons hitting the plate.

Even with carrier particles flowing through the process, it's still a "pressure difference" between the outside and inside of the plates, not "negative pressure". You're still confusing the concept of "ABSOLUTE" pressure with relative pressure.

You're still confusing real photons and virtual photons.

[qimg]http://upload.wikimedia.org/wikipedia/commons/thumb/4/44/Casimir_plates.svg/300px-Casimir_plates.svg.png[/qimg]

I have no idea why you are showing that picture, but its wrong.

 

[edd]

It's ultimately just a 'pressure difference'. There is "less pressure" on the insde of the plates and "more pressure" on the outside of the plates. While you can refer to this pressure difference as a "negative number" is has nothing whatsoever to do with the absolute pressure in the chamber as demonstrated by the fact that works at almost any pressure.

[in reply to whether -dE/dV is the definition of pressure]

You haven't answered whether or not you accept dE/dV as a definition of pressure. Which is probably wise, as if you answer 'no' you're not talking about the same quantity that is cosmologically relevant, so please answer yes.

When you have done so - look back at your cartoon of the situation in the Casimir Effect. Note two things, two things I have pointed out before to you:
a) The Casimir effect is not known to be related to dark energy. It may or may not have some tie, but arguing against it does not argue against dark energy.
b) The Casimir effect is strongly related to geometry. It is also intimately bound up with deeper level quantum mechanics - bosonic fields and fermionic fields act very differently with it. It is not hard to make the Casimir effect attractive. This should be a strong clue to you that your cartoon is a cartoon, and not an accurate representation of reality.
c) -dE/dV. This is the important quantity, whether it's called pressure or not. Cosmologically, we don't give a monkey's about pressure differences acting on metal plates, we want to know how energy changes with volume. What is the sign on that quantity, in the context of the Casimir effect? Ignore any pressure actually acting on the plates, how much does the energy change in the plates as the volume in the plates change?

 

[GeeMack]

Keep in mind I provided them with plenty of links and even some pretty little pictures from multiple sources to demonstrate all this and all they did was ignore every little bit of it.

You just can't stress enough how pretty little pictures are the basis for all good science. Math be damned!

 

[Pythonic]

a) The Casimir effect is not known to be related to dark energy. It may or may not have some tie, but arguing against it does not argue against dark energy.

MM, if edd's statement is true, does that change your claim at all? Is your claim completely dependent on the Casimir effect?

 

[ben m]

-dE/dV. This is the important quantity, whether it's called pressure or not. Cosmologically, we don't give a monkey's about pressure differences acting on metal plates, we want to know how energy changes with volume.

This is an important point. GR describes how mass moves and spacetime evolves with energy density. Large-scale, late-time cosmology is nothing more than solving the GR evolution equations with TWO energy densities: mass energy density (a positive quantity) and vacuum energy density (a positive quantity).

It gets relabeled negative pressure because physicists are perfectly conversant with both positive and negative pressures. But when you're actually sitting there asking yourself, "OK, what's the curvature tensor at z=10", the thing you plug into the equations is the (positive) energy density. When you plug the energy density in again at z=9, you'd find that it hasn't decreased---because it's vacuum energy---and you might shrug and say "huh, that happens to be the opposite of what a positive pressure would do".

 

[Tubbythin]

Note two things, two things I have pointed out before to you:
a) The Casimir effect is not known to be related to dark energy. It may or may not have some tie, but arguing against it does not argue against dark energy.
b) The Casimir effect is strongly related to geometry. It is also intimately bound up with deeper level quantum mechanics - bosonic fields and fermionic fields act very differently with it. It is not hard to make the Casimir effect attractive. This should be a strong clue to you that your cartoon is a cartoon, and not an accurate representation of reality.
c) -dE/dV. This is the important quantity, whether it's called pressure or not. Cosmologically, we don't give a monkey's about pressure differences acting on metal plates, we want to know how energy changes with volume. What is the sign on that quantity, in the context of the Casimir effect? Ignore any pressure actually acting on the plates, how much does the energy change in the plates as the volume in the plates change?

Errm. That would be three things .

 

[Michael Mozina]

MM, if edd's statement is true, does that change your claim at all? Is your claim completely dependent on the Casimir effect?

No it does not change anything at all from my perspective. It's a "physical principle" issue now. This "negative pressure" debate actually began with our discussion about Guth's original inflation paper. In that paper Guth tried to claim that the "vacuum" had a "negative pressure", at which point it became abundantly clear that he was completely detached from physics, specifically the physics of "pressure" in a vacuum. He did not understand or consider the physical limits of 'physical' reality or the concept of "pressure" in a vacuum at the level of kinetic energy. It is physically impossible to create "negative pressure' in a vacuum.

While it is very clear that these individual understand their math *very* well, when it comes to subatomic physics, they are evidently clueless about what goes on in a vacuum at the level of kinetic energy and actual physics.

This debate does demonstrate a significant lack of understanding on their part about kinetic energy and actual "physics". That lack of physical understanding of what is going on directly effects our magnetic reconnection debate, and it has a direct effect on their inability to see the glaring weaknesses of "dark energy theory" and "inflation theory" (not so much dark matter theory).

At the level of "physics" it's helpful to begin to understand the "pressure" in a "vacuum" from the standpoint atomic pressure. The "pressure" in the vacuum chamber is caused by the atoms kinetically interacting with the sides of the walls of the chamber (or something inside the chamber). The atoms bounce around and bang into things. As we increase the temperature of the chamber, even with the same number of atoms in the chamber, the "pressure' will increase with temperature because the kinetic energy of the atoms is greater as the temperature rises. The atoms are moving faster inside the chamber and their kinetic energy has increased. Pressure in the vacuum is directly related to the kinetic energy in the particles in the chamber. Pressure in the vacuum and kinetic energy are intimately and directly (physically) related. Since all vacuums have some atoms, all vacuums have pressure of some kind.

Even the best physical vacuums on Earth cannot ever be "empty". We don't have the technology to remove every atom from a vacuum and therefore we can never reach a "zero" atomic pressure state in a "vacuum". We simply can't remove *every* physical particle with kinetic energy from a chamber. It's impossible for us to do that. Even if we could, there are still neutrinos blowing through the chamber by the billions. There will still be particle kinetic energy inside every 'vacuum" in the universe, even if it were a 'perfect' (not a single atom in the chamber) vacuum.

Even without any atoms at all inside our mythical perfect vacuum, there would still be an abundance of kinetic energy flowing inside the chamber due to the kinetic energy from neutrinos that flow through the vacuum by the billions. This particle kinetic energy creates pressure even in the absence of all atoms.

It's pretty clear from the importance of the material used in the plates that the kinetic energy of the EM carrier particles that produce "pressure" on the plates. They do so by putting *MORE* pressure on the outside and *less* on the inside. That diagram from Wiki is well done and explains the process quite clearly. The little blue arrows on the inside of the plates still press into the plates. They are simply 'small than' (less kinetic energy than) the arrow on the outside of the plates. There's nothing mysterious about the Casimir effect as long as you recognize it's the carrier particle of the EM field that passes on it's kinetic energy to *ALL SIDES* of the plates.

FYI, it is possible geometrically to make the Casimir effect "repulsive". As Edd say's, it's not easy, but it's directly related to a "greater" pressure in one area, and "lower pressure" in another area.

I think it was clear to everyone that "dark energy' has nothing to do with the Casimir effect. If it did, the type of material in the plate wouldn't be relevant. The fact that the plates have to be metal suggests that the kinetic energy comes from the carrier particles of the EM field rather than any other particle.

 

[Perpetual Student]

MM says above that Guth does not understand "actual physics" but he does. That is quite remarkable!

 

[Michael Mozina]

a) The Casimir effect is not known to be related to dark energy. It may or may not have some tie, but arguing against it does not argue against dark energy.

No, it's evidently the carrier particle of the EM field passing on the kinetic energy. The whole "negative pressure in a vacuum" debate started with Guth's inflation paper, not DE.

b) The Casimir effect is strongly related to geometry. It is also intimately bound up with deeper level quantum mechanics - bosonic fields and fermionic fields act very differently with it. It is not hard to make the Casimir effect attractive.

I agree.

This should be a strong clue to you that your cartoon is a cartoon, and not an accurate representation of reality.

No edd, just the opposite is true. The diagram (which I did not personally create) and the others I have provided is exactly correct. There is "greater" pressure on the outside of the plates and "less" pressure on the inside, but there is "pressure" on every side of every plate. The diagram (which Michael Mozina had nothing to do with) and the one right below that too on the same WIKI page, correctly describe the process in terms *MORE* and *LESS* pressure in various areas. That's why geometry is so critical. There's nothing wrong with the diagram, just something wrong with your grasp of kinetic particle "pressure".

c) -dE/dV. This is the important quantity, whether it's called pressure or not. Cosmologically, we don't give a monkey's about pressure differences acting on metal plates, we want to know how energy changes with volume.

Since we were debating the validity of Guth's claim about a vacuum having negative "pressure", the only way to win that debate is to pay attention to the pressure on the plates. That's the "pressure" caused by the kinetic energy transfer from the EM field to the plates. There is PRESSURE pushing *INTO* (not away from) all sides of all the plate. The "vacuum" is full of "pressure". From the standpoint of kinetic energy and actual physics, there is simply no physical way in hell to create a "negative pressure" in a "vacuum". Guth's claim (and all math based on such a claim) is utterly bogus.

 

[Michael Mozina]

MM says above that Guth does not understand "actual physics" but he does. That is quite remarkable!

I'm sure that Guth understands many things about physics, but when it comes to "negative pressure" in a "vacuum", that particular claim is completely out to lunch, and physically impossible.

 

[GeeMack]

MM says above that Guth does not understand "actual physics" but he does. That is quite remarkable!

Maybe Guth actually understands math, where clearly Michael doesn't. Maybe Guth doesn't think the principles of physics are best described using pretty little pictures, where clearly Michael does. Maybe Guth actually understands the scientific method, issues like burden of proof, the fact that arguments from ignorance aren't evidence, that quantitative descriptions are absolutely necessary to the science of physics, and such simple concepts of science, where clearly Michael doesn't. Maybe it's those fundamental differences that cause Michael to misperceive Guth's understanding of actual physics.

 

[Michael Mozina]

Errm. That would be three things .

 

[Michael Mozina]

Maybe Guth actually understands math, where clearly Michael doesn't.

Pure slanderous BS. From a "math" standpoint it's just a minus sign. Anyone that has learned to add and subtract "understands" the mathematical meaning of a minus sign. It's at the level of real kinetic energy physics where his (your) argument goes to hell in a handbasket.

 

[Perpetual Student]

I'm searching for a word...hmm...searching...hmm... ah ha -- HUBRIS!

 

[Michael Mozina]

I'm searching for a word...hmm...searching...hmm... ah ha -- HUBRIS!

Well, believe it or not, I do have a sense of humor about it and I do realize how it sounds.

Then again, spend a little time thinking about the kinetic energy state of a "vacuum" and ask yourself how the "pressure" of all that kinetic energy could ever become "negative"?

The best you might hope to achieve is a "zero" kinetic energy state (no particle/subatomic particles flow) in the vacuum. We can't create a 'negative' kinetic energy state, so there is no way to create a "negative pressure" in a "vacuum". In a vacuum, particle kinetic energy and "pressure" are physically related processes. It's physically impossible for a vacuum to contain "negative pressure". From the standpoint of kinetic energy physics: "Foregetaboutit".

 

[Michael Mozina]

The Casimir effect is not the effect or real photons hitting the plate.


You're still confusing real photons and virtual photons.

It doesn't matter if you think that kinetic energy transfer comes for photons or virtual photons, it's still a kinetic energy transfer to *ALL* sides of *ALL* plates.

I have no idea why you are showing that picture, but its wrong.

Then the one right below it on the same WIKI page must also be wrong, and the other diagrams I have posted here must also all be wrong, and all those articles I cited must all be "wrong" as well. Of course it could be they are all correct and you are just not considering "pressure' from the standpoint of kinetic energy. FYI, I didn't create any of those diagrams.

 

[Tubbythin]

No it does not change anything at all from my perspective. It's a "physical principle" issue now. This "negative pressure" debate actually began with our discussion about Guth's original inflation paper. In that paper Guth tried to claim that the "vacuum" had a "negative pressure", at which point it became abundantly clear that he was completely detached from physics, specifically the physics of "pressure" in a vacuum. He did not understand or consider the physical limits of 'physical' reality or the concept of "pressure" in a vacuum at the level of kinetic energy. It is physically impossible to create "negative pressure' in a vacuum.

No it isn't. As the Casimir effect quite clearly demonstrates.

While it is very clear that these individual understand their math *very* well, when it comes to subatomic physics, they are evidently clueless about what goes on in a vacuum at the level of kinetic energy and actual physics.

It is clear that you are talking rubbish. For example, Guth got a degree, a master's and his doctorate from one of (if not) the foremost institutions for physics in the world. His PhD thesis was on "was an exploration of an early model of how quarks combine to form the elementary particles that we observe". You, on the other hand, get your research from wikipedia.

This debate does demonstrate a significant lack of understanding on their part about kinetic energy and actual "physics".

I'm sorry. You are the one who just claimed there was no such thing as a vacuum energy even though the article from wikipedia you loved so much explicitly states there is.

That lack of physical understanding of what is going on directly effects our magnetic reconnection debate,

They don't lack an understanding, you do. You thought there was no such thing as vacuum energy.

and it has a direct effect on their inability to see the glaring weaknesses of "dark energy theory" and "inflation theory" (not so much dark matter theory).

You don't even know what these theories say. All you do is talk about faeries and dead deities.

At the level of "physics" it's helpful to begin to understand the "pressure" in a "vacuum" from the standpoint atomic pressure.

There is no atomic pressure in a vacuum.

The "pressure" in the vacuum chamber is caused by the atoms kinetically interacting with the sides of the walls of the chamber (or something inside the chamber). The atoms bounce around and bang into things. As we increase the temperature of the chamber, even with the same number of atoms in the chamber, the "pressure' will increase with temperature because the kinetic energy of the atoms is greater as the temperature rises. The atoms are moving faster inside the chamber and their kinetic energy has increased. Pressure in the vacuum is directly related to the kinetic energy in the particles in the chamber. Pressure in the vacuum and kinetic energy are intimately and directly (physically) related. Since all vacuums have some atoms, all vacuums have pressure of some kind.

Its not really relevant how perfect the vacuum is. But the average density of the Universe is around one hydorgen atom per cubic metre. And space doesn't have walls. Something you seem to have failed to realise.

Even the best physical vacuums on Earth cannot ever be "empty". We don't have the technology to remove every atom from a vacuum and therefore we can never reach a "zero" atomic pressure state in a "vacuum". We simply can't remove *every* physical particle with kinetic energy from a chamber. It's impossible for us to do that.

So? The Universe does not have walls.

Even if we could, there are still neutrinos blowing through the chamber by the billions.

I did this very roughly before. In Casimir type experiments, if we're unlucky we may get one neutrino interaction on each plate per year. Neutrinos are completely and utterly irrelevant.

There will still be particle kinetic energy inside every 'vacuum" in the universe, even if it were a 'perfect' (not a single atom in the chamber) vacuum.

There's the vacuum fluctuations.

Even without any atoms at all inside our mythical perfect vacuum, there would still be an abundance of kinetic energy flowing inside the chamber due to the kinetic energy from neutrinos that flow through the vacuum by the billions. This particle kinetic energy creates pressure even in the absence of all atoms.

Care to calculate the pressure exerted by neutrinos, bearing in mind we have an interaction rate of order 1 per year?

It's pretty clear from the importance of the material used in the plates that the kinetic energy of the EM carrier particles that produce "pressure" on the plates.

The type of material tells us the boundary conditions. In the case of two metallic plates, the boundary conditions tell us that the modes must have nodes at the plate boundaries. That is why the allowed standing waves must have wavelengths shorter than twice the plate width.

They do so by putting *MORE* pressure on the outside and *less* on the inside. That diagram from Wiki is well done and explains the process quite clearly. The little blue arrows on the inside of the plates still press into the plates. They are simply 'small than' (less kinetic energy than) the arrow on the outside of the plates. There's nothing mysterious about the Casimir effect as long as you recognize it's the carrier particle of the EM field that passes on it's kinetic energy to *ALL SIDES* of the plates.

The diagram from wikipedia is wrong.

FYI, it is possible geometrically to make the Casimir effect "repulsive". As Edd say's, it's not easy, but it's directly related to a "greater" pressure in one area, and "lower pressure" in another area.

I think it was clear to everyone that "dark energy' has nothing to do with the Casimir effect. If it did, the type of material in the plate wouldn't be relevant. The fact that the plates have to be metal suggests that the kinetic energy comes from the carrier particles of the EM field rather than any other particle.

We know exactly where the pressure comes from. That's why the experiment was designed. Have you actually read the wikipedia page you like so much? There was never any doubt. This was something Casimir derived from quantum field theory (using loads if that maths you hate so much) and then designed an experiment to test it and then tested it. It isn't some anomalous result that nobody understood.

 

[Tubbythin]

Pure slanderous BS.

Erm. You're the one who said one of the foremost physicists in the world didn't understand subatomic theory. And then backed it up with zero evidence.
Oh, and it'd be libel anyway.

 

[Tubbythin]

It doesn't matter if you think that kinetic energy transfer comes for photons or virtual photons, it's still a kinetic energy transfer to *ALL* sides of *ALL* plates.

The virtual photons don't really transfer anything anywhere.

Then the one right below it on the same WIKI page must also be wrong,

Its a bit vague to say.

and the other diagrams I have posted here must also all be wrong,

I don't particularly remember other diagrams. Possibly, possibly not.

and all those articles I cited must all be "wrong" as well.

Not at all. Not unless they cited that wikipedia diagram (which I doubt).

Of course it could be they are all correct and you are just not considering "pressure' from the standpoint of kinetic energy.

Its wrong because the whole point of the Casimir effect is that the standing waves must have nodes at the surface of the metallic plate. That is not the case in the diagram.

FYI, I didn't create any of those diagrams.

You're not the only one who can be wrong you know.

 

[Tubbythin]

Well, believe it or not, I do have a sense of humor about it and I do realize how it sounds.

Then again, spend a little time thinking about the kinetic energy state of a "vacuum" and ask yourself how the "pressure" of all that kinetic energy could ever become "negative"?

The best you might hope to achieve is a "zero" kinetic energy state (no particle/subatomic particles flow) in the vacuum. We can't create a 'negative' kinetic energy state, so there is no way to create a "negative pressure" in a "vacuum". In a vacuum, particle kinetic energy and "pressure" are physically related processes. It's physically impossible for a vacuum to contain "negative pressure". From the standpoint of kinetic energy physics: "Foregetaboutit".

We don't need to create a negative kinetic energy state. We need to create a state for which dE/dV is positive. That is the case in question here.