Lambda-CDM theory - Woo or not?

[Ziggurat]

It does not. I offered to let you folks use mass rather than energy and your side balked at that idea too.

No. First off, it was me, not my "side". Second, I told you why that substitution was pointless and stupid, and you didn't have any response. And third, if you do use that substitution, you will not end up with the ideal gas law. Because the ideal gas law does indeed ignore relativity. It breaks down for relativistic particles (which is part of why it doesn't work for radiation pressure). The quantum issue is a little more subtle: you can derive it using the quantum energy states (using the definition of pressure I gave earlier), but you need to use Maxwell-Boltzmann statistics, not Fermi-Dirac or Bose-Einstein, so it definitely ignores aspects of quantum mechanics.

 

[Michael Mozina]

No. First off, it was me, not my "side".

It was *you* doing all trash talking and insisting on a mathematical description of pressure in a vacuum. The moment I handed you a valid option, you got all huffy and puffy and refused to consider it. You didn't like the second one either.

Second, I told you why that substitution was pointless and stupid, and you didn't have any response.

It is not "pointless" or "stupid" if we're talking about the "pressure" of a "vacuum". What was "pointless and stupid" was comparing a vacuum to "liquids". The only reason you balked at my suggestions is that it becomes clear that with no mass, you have no pressure.

And third, if you do use that substitution, you will not end up with the ideal gas law. Because the ideal gas law does indeed ignore relativity. It breaks down for relativistic particles (which is part of why it doesn't work for radiation pressure). The quantum issue is a little more subtle: you can derive it using the quantum energy states (using the definition of pressure I gave earlier), but you need to use Maxwell-Boltzmann statistics, not Fermi-Dirac or Bose-Einstein, so it definitely ignores aspects of quantum mechanics.

The QM issue is *directly related to a persistent, all pervasive EM fields in the vacuum and the carrier particles for the EM field. It is a *force*, not a "pressure" and it never become negative either. All the "blue arrows" would be pointing directly at Guth's singularity thingy and would act to *push it together*, not pull it apart. There is no such thing a "negative pressure".

You folks still have not acknowledged that the Casimir *force* is a *force* that is unrelated to "pressure". There is "kinetic energy" conveyed the by the force of the carrier particles of EM field, but it is ultimately unrelated to "pressure". The existence of primordial and pervasive EM field would only hurt Guth's inflation process, it would not, and could not help it. Instead of having a true "zero" pressure from a pure vacuum, Guth's near singularity thingy will experience a slight positive pressure from the level of QM. In no way will Guth ever get "negative pressure" out of a vacuum, not even at the level of QM. All he might get is moving particles inside some primordial field bombarding his singularity and putting "pressure" on it. In other words it would only be "kinetic energy in motion" slamming into his "heat" thingy from all sides.

 

[temporalillusion]

You folks still have not acknowledged that the Casimir *force* is a *force* that is unrelated to "pressure".

What do you mean by pressure in the sentence? a) gaseous pressure b) atmospheric pressure c) something else?

So you have your blue arrows in your diagram. They are pointing in opposite directions. What are the signs on each of those vectors? Positive or negative?

 

[edd]

You folks still have not acknowledged that the Casimir *force* is a *force* that is unrelated to "pressure". There is "kinetic energy" conveyed the by the force of the carrier particles of EM field, but it is ultimately unrelated to "pressure". The existence of primordial and pervasive EM field would only hurt Guth's inflation process, it would not, and could not help it. Instead of having a true "zero" pressure from a pure vacuum, Guth's near singularity thingy will experience a slight positive pressure from the level of QM. In no way will Guth ever get "negative pressure" out of a vacuum, not even at the level of QM. All he might get is moving particles inside some primordial field bombarding his singularity and putting "pressure" on it. In other words it would only be "kinetic energy in motion" slamming into his "heat" thingy from all sides.

I don't think you quite understand what's supposed to be happening. At inflation there is no "outside" for particles to be coming from to be impinging on some supposed singularity (inflation happens after any singularity, if there's a singularity at all).

Also the pressure itself is not acting by hitting things and causing them to move in the cosmological context (not least as there's no outside for them to be coming from in order to hit something). You do understand the role pressure has in relativity, don't you?

 

[temporalillusion]

You do understand the role pressure has in relativity, don't you?

Actually I don't think I do. Once you've given MM a chance to answer, if you would be so kind..

 

[Michael Mozina]

It's not a definition of pressure at all. Under any conditions. Even for an ideal gas. How can you still not get such a basic fact straight?

Baloney. As it relates to *atoms* at the atomic level, it's a perfectly valid way to determine the asymptote for "pressure" in a vacuum. It isn't "negative infinity", it's "zero". We can then look at the subatomic energy spectrum if you like, but as it relates to "pressure" in a vacuum, it's a perfectly valid definition. You just don't like it because it demonstrates that the asymptote for pressure is zero, not "the negative energy state of a whole physical universe".

Hell, it can even give the radically WRONG pressure, as in the case of radiation pressure (which is not the Casimir effect -

This is simply "kinetic pressure" at the level of subatomic physics. There's nothing "magical" going on at the subatomic scale, it's still kinetic energy in motion.

I'm talking real photons).

Evidently those would necessarily be coming from the heat object rather than the "vacuum around the heat object". How exactly did all that "heat" get out of Guth's thingamabob again if not via photons coming *from* it?

Radiation pressure inside a sealed enclosure will scale as T⁴ (Reif, Thermal Physics), not as T, so the ideal gas law is rather obviously wrong, and at sufficiently high temperature, radiation pressure will always dominate gas pressure.

The radiation pressure as you call it is simply kinetic energy in motion because we live inside an electric universe. Where's that radiating energy coming from in Guth's theory? What form of energy are we discussing as it relates to Guth's theory? Are you depending upon a giant external EM field? Are you sure you aren't EU theorists in Lambda "drag"?

 

[Michael Mozina]

Actually I don't think I do. Once you've given MM a chance to answer, if you would be so kind..

Until Guth has mass, how does "relativity" apply again?

 

[Michael Mozina]

I don't think you quite understand what's supposed to be happening. At inflation there is no "outside" for particles to be coming from to be impinging on some supposed singularity (inflation happens after any singularity, if there's a singularity at all).

Is there any mass at this point? Guth doesn't seem to imply this to be the case. What *holds* his "heat" exactly? How does it "supercool" if not by releasing photons?

Also the pressure itself is not acting by hitting things and causing them to move in the cosmological context (not least as there's no outside for them to be coming from in order to hit something).

So what is *causing* this "pressure" you're describing if there is no "outside" and no way for anything from the "outside" to have any effect on it?

You do understand the role pressure has in relativity, don't you?

I don't have a clue how it applies until you have "mass" in some "form".

 

[Ziggurat]

It was *you* doing all trash talking and insisting on a mathematical description of pressure in a vacuum.

Well, no. What I insisted on was a universal definition of pressure.

The moment I handed you a valid option, you got all huffy and puffy and refused to consider it.

I did consider it. And I told you why, in detail, it was awkward and pointless, starting with the fact that relativistic mass is an outdated and redundant concept. All you did was change the calculation from one in terms of energy to one in terms of relativistic mass, which is redundant with energy. So although the two versions were formally equivalent, I detailed why your form was inferior for performing actual calculations. You did not actually contest that.

It is not "pointless" or "stupid" if we're talking about the "pressure" of a "vacuum".

Sure it is. Relativistic mass is redundant with energy. In most situations it's easier to work with energy directly rather than with relativistic mass.

What was "pointless and stupid" was comparing a vacuum to "liquids".

Oh, but I'm not comparing them. I'm using liquids to demonstrate that you have no clue about what pressure actually means.

The only reason you balked at my suggestions is that it becomes clear that with no mass, you have no pressure.

Oh, is that what you thought you were doing? Sorry, I really didn't think you'd be so clueless, but I guess I should have known better by now. Well, this is rather obviously wrong, because you've confused rest mass with relativistic mass (one of the reasons I prefer not to ever use relativistic mass). Radiation pressure is the perfect counter-example: no rest mass, plenty of relativistic mass, and you get pressure. So apparently you didn't even have a clue about what your substitution meant.

The QM issue is *directly related to a persistent, all pervasive EM fields in the vacuum and the carrier particles for the EM field. It is a *force*, not a "pressure"

A force that's applied over an area, and that force is proportional to the area that it's applied over. Divide out that area, and you get a constant, which is...
(wait for it)...
Pressure!

Who'da thunk? As those intro textbooks repeatedly point out, pressure is force per area. So the EM field is indeed applying a pressure. And whether you want to consider ordinary radiation pressure or the Casimir effect, you CANNOT substitute mass for energy in my pressure equation unless you use relativistic mass. But the EM field can (and does) indeed have relativistic mass, so your contention that my definition of pressure leads to zero pressure for a vacuum is wrong.

There is no such thing a "negative pressure".

Once again, yes there is. Whether or not a vacuum can support negative pressures is a different question, but negative pressures are absolutely real. Again, liquids. Yes, yes, liquids aren't the same thing as vacuums, but your repeated failure to understand that liquids can have negative pressure demonstrates that you don't know what pressure is.

You folks still have not acknowledged that the Casimir *force* is a *force* that is unrelated to "pressure".

It's a force applied over an area. Divide out that area, and what do you get? A pressure. Seems pretty obviously related to me. And my intro physics textbook says the same thing. In fact, when calculating the pressure of a liquid at depth, it starts out with calculating a force, then derives the pressure from that.

Really, Michael. Don't bother trying to figure out the quantum mechanics of all this. You're still hopelessly clueless about what pressure means, even in a Newtonian context.

 

[edd]

Until Guth has mass, how does "relativity" apply again?

Well I think I can reasonably take that to be a 'no' in answer to my question of whether you understand.

temporalillusion - broadly speaking the source of gravity in GR is not purely mass. This is to be expected given what we know of the equivalence of mass and energy, but in more detail the source of gravity in GR is the energy-momentum tensor, aka stress-energy tensor. One component of that is the energy density (again not just mass but all the energy) and it also has terms including stresses, momentum in each direction, energy fluxes and, of course, pressure.

In a cosmological situation we make the (very good) simplifying assumption that everything is a perfect fluid - this takes out all the momentum terms, energy fluxes and all stresses and just leaves us worrying about density and pressure.

We can take that, with Einstein's equations and some assumptions like the universe is the same everywhere and looks the same in every direction and use equations of state for each component of our universe (which relate something's energy density to its pressure) and come out with equations to describe how the universe changes over time.

In one of those equations you'll see the pressure is still there quite explicitly - and it implicitly affects the others through the equations of state.

The pressure is acting in these equations in a purely gravitational manner. This is not a physical impact resulting from the pressure acting on some plate - it's all gravity at work here.

This is fairly clear if you think about what a cosmological constant is supposed to be doing. It's supposed to be making the universe accelerate. This is quite counter to what a box filled with a negative pressure substance is supposed to be doing. The actual pressure on the walls of the box would then be pointing inwards trying to make the box contract. This is not what is happening cosmologically though.

As I mentioned before but MM has apparently not picked up in his last post (edit: at time of starting to write this - posted again since) - there is no outside here for the pressure to be acting from or against. It's not pressure at work in the same way it's at work in a balloon or indeed in the Casimir plate experiment - it's a common misunderstanding that the early universe expanded because it was hot and at high pressure and it's somehow forcing outwards as a result. This is not the case.

 

[Ziggurat]

Baloney. As it relates to *atoms* at the atomic level, it's a perfectly valid way to determine the asymptote for "pressure" in a vacuum.

Yup. You don't understand the definition of "definition". Regardless of the ideal gas law's utility in determining pressure, it IS NOT how anyone DEFINES pressure. And you've shown no sign that you've got any clue about how to define pressure.

It isn't "negative infinity", it's "zero".

So? It only describes an ideal gas. It does not describe radiation pressure, or anything else besides an ideal gas.

We can then look at the subatomic energy spectrum if you like,

Yes, let's do that. How can you calculate the pressure from the Casimir effect using the ideal gas law? Hint: you can't. Oh, but you think that's not a pressure, even though it's a force applied over an area. OK, how about ordinary radiation pressure? Can we use it to calculate that? Well, no. Photons are relativistic particles. The ideal gas law is valid only for nonrelativistic particles. They've got the wrong energy/momentum relationship, so it will not work. If you care, I can go through the math, but you seem allergic to math.

The radiation pressure as you call it is simply kinetic energy in motion because we live inside an electric universe. Where's that radiating energy coming from in Guth's theory?

We're not at a point yet where we can discuss this meaningfully, because you still don't understand what pressure is, or how to define it.

 

[Michael Mozina]

Here you go.....

http://singularityhub.com/2009/01/08/nanoscale-levitation-repulsive-casimir-force-verified/

The *geometry* of the objects determines the direction of force. The article has a link to a paper on this topic. The "force" does not cause "negative pressure", otherwise that levitation trick would not be possible. It is simply a "force" created by the carrier particles of the EM field. There is simply "kinetic energy in motion" at the level of the EM field. There is no such thing as "negative pressure", just "objects in motion" that convey kinetic energy, or not. Even if there was no EM field influence, the asymptote for "pressure" at the atomic and subatomic scale is "zero". It can never be "negative" because there is always kinetic energy in motion inside even the best "vacuums" on Earth, both at the level of atomic "pressure" and 'subatomic force".

 

[Ziggurat]

As I mentioned before but MM has apparently not picked up in his last post (edit: at time of starting to write this - posted again since) - there is no outside here for the pressure to be acting from or against. It's not pressure at work in the same way it's at work in a balloon or indeed in the Casimir plate experiment - it's a common misunderstanding that the early universe expanded because it was hot and at high pressure and it's somehow forcing outwards as a result. This is not the case.

Oh, don't confuse the poor boy. He can't even sort out what pressure means in a purely classical Newtonian context, you can't possibly expect him to understand what you're talking about.

 

[Michael Mozina]

This is fairly clear if you think about what a cosmological constant is supposed to be doing. It's supposed to be making the universe accelerate. This is quite counter to what a box filled with a negative pressure substance is supposed to be doing. The actual pressure on the walls of the box would then be pointing inwards trying to make the box contract. This is not what is happening cosmologically though.

What is "happening" cosmologically in an acceleration process of a mostly plasma universe, and the *most likely* force/field that could have such an influence would be the EM field. There is no such thing as "dark energy" and "dark energy" has no effect on plasma, whereas MHD theory describes the mathematical processes of the effects of the EM field on plasma.

As I mentioned before but MM has apparently not picked up in his last post (edit: at time of starting to write this - posted again since) - there is no outside here for the pressure to be acting from or against.

Then there can be no "negative pressure" in the vacuum to "balance out" anything in Guth's theory.

 

[Michael Mozina]

Oh, don't confuse the poor boy. He can't even sort out what pressure means in a purely classical Newtonian context, you can't possibly expect him to understand what you're talking about.

Oh right. You can't even distinguish between "pressure" and "force" and somehow it's all my fault now? Of course the fact that geometry is directly related to the direction of that force blows your whole show out of the water, but you're evidently in pure denial of that point.

 

[Ziggurat]

Oh right. You can't even distinguish between "pressure" and "force"

... said the man who can't define pressure.

 

[Michael Mozina]

... said the man who can't define pressure.

I've defined "pressure in a vacuum", twice for you now. You just don't like the implications of the asymptote at zero.

 

[edd]

What is "happening" cosmologically in an acceleration process of a mostly plasma universe, and the *most likely* force/field that could have such an influence would be the EM field. There is no such thing as "dark energy" and "dark energy" has no effect on plasma, whereas MHD theory demonstrates the mathematical processes of the effects of the EM field on plasma.

This is not a way to defend yourself from the point I was making. I was describing the derivation of standard cosmological models in quite broad circumstances and explaining the role of pressure within them, regardless of whether they actually represent the real universe.

It's entirely valid within the context of GR, entirely general including universes with no negative pressure constituents and it was a point put forward to highlight your lack of understanding of the role pressure has in gravity.

You might choose to argue that it isn't representative of the universe as we see it but it does highlight that you don't understand the standard model and are therefore in a poor position to criticise it. It is also a concern given that I was under the (possibly mistaken) impression that EU proponents accepted GR as a good description of gravity.

 

[edd]

I've defined "pressure in a vacuum", twice for you now. You just don't like the implications of the asymptote at zero.

It's not even an asymptote mate.

 

[Michael Mozina]

This is not a way to defend yourself from the point I was making. I was describing the derivation of standard cosmological models in quite broad circumstances and explaining the role of pressure within them, regardless of whether they actually represent the real universe.

But this whole conversations is specifically related to me criticizing Guth's definition of a negative pressure in a vacuum to "balance" his "expansion process". It's not physically possible to have "negative pressure' in a "vacuum".

It's entirely valid within the context of GR, entirely general including universes with no negative pressure constituents and it was a point put forward to highlight your lack of understanding of the role pressure has in gravity.

IMO you're still missing the whole point of what I've been trying to explain to you about pressure. The "kinetic energy" transfer at the subatomic level could indeed "push" a universe apart, whereas your side's notion of "negative pressure" involved in the Casimir effect, would not and does not work to even explain all the various geometric effects of the Casimir effect.

The only reason the Casimir effect occurs in the first place is because we live inside an electric universe with lots of kinetic energy flowing through it at all times.