Lambda-CDM theory - Woo or not?

[edd]

Michael, if the argument were that simple please explain why bosonic fields result in the plates being pulled together while fermionic fields push the plates apart?
It really is not quite as simple as the Physics World article makes out. I'm sorry you've been mislead by this explanation of the effect.
The pressure is negative, and this can be seen quite directly from what I've said before - the energy between the plates drops as they move together. This is a negative pressure.

 

[Reality Check]

You know, the funny part of this statement is that you refuse to acknowledge that *both of your starting numbers (A and B) are each positive numbers*, and all you're describing is the "relative difference between these two positive numbers". In the visual aid, that means B is the positive outside pressure, and A is the positive inside pressure, and there is simply a difference between them. The same is true in the wing pressure scenario, only B) would be the pressure under the wing, and A) would be the positive pressure on the top of the wing, and your math formula represents the difference between them. How can you not "get it"?

You are right: I assumed that since you deny the existence of negative pressure, you would also deny the existence of negative numbers !

 

[DeiRenDopa]

Since you *REFUSE* to answer my questions about your personal beliefs(like what got your party started in the absence of inflation), the size of the object before 'expansion', etc, why should I feel compelled to answer any of your questions?

(bold added)

What you feel you need, want, are compelled, etc to do is something I have no desire to explore, or even to know.

If you feel that objectivity and the (in principle) ability to independently verify stuff are key, foundational, aspects of contemporary science, then your personal opinions, beliefs, etc are surely irrelevant ... as are mine, are they not?

Let's remind ourselves of the scope of this thread, shall we?

It is whether LCDM cosmological models are (scientific) woo or not.

Now as has been pointed out - repeatedly - that question was answered on the first page of this thread (such models are good examples of what contemporary science - astrophysics and cosmology in this case - is).

However, you, MM, hold a different opinion.

To the extent that that opinion is, in principle, objective and independently verifiable, a question that many of those posting to this thread are exploring,

The consensus so far seems to be that that opinion - as presented so far in this thread - is illogical, internally inconsistent, full of factual errors and misstatements, etc. And the opinion is, AFAICS, built on a view of science that excludes (by fiat?) mathematics and any form of quantitative evidence or reasoning.

To the extent that that opinion does contain some elements of logical consistency, it seems to rely upon the concepts of 'known forces of nature' and for these to be objectively demonstrable (and independently verifiably so), in purely qualitative ways.

My questions are designed to test whether this idea is internally consistent.

I trust that this clarifies things for you (and any other reader who may have wondered similar things).

 

[Reality Check]

So you just *IGNORE* the experiments where it become "positive"?

How is that not *CLASSIC* denial?

The experiments where the Casimir pressure are positive are not *IGNORED*.

They are nothing to do with the cartoon that you are obssessed with. That diagram is for the case of an attractive force from the Casimir effect and thus a negative pressure.
You did read the wikipedia article on the Casimir effect, MM? Or is this a case of *CLASSIC* denial?

 

[Reality Check]

Michael, please see my earlier post. That image is little more than a cartoon. Those blue arrows are not really a good representation of the pressure.

You cannot do quantum mechanics with cartoons.

Unless you're Richard Feynman.

Ditto.

Michael Mozina:
FYI - the blue arrows are definitely forces not pressure.
Since you do not know what the definition of pressure is, you will have to trust me and Wikipedia when I say that it is a scalar quantity. You will also have to trust me and Wikipedia when I say that force is a vector quantity (someone who does not know the definition of pressure is unlikely to know the definition of force).
A scalar quantity is basically a number.
A vector quantity is both a number and a direction. They are shown in diagrams as arrows.

 

[Michael Mozina]

You are right: I assumed that since you deny the existence of negative pressure, you would also deny the existence of negative numbers !

I just don't see how you can ignore the fact you have 'pressure' in terms of air, "force" in terms of QM and no forms of "negative pressure" or "negative force" in these processes. Just like the wing analogy, all you have is evidence of "less pressure" between the plates and "more pressure" outside of the plates, and a difference between them.

Guth needs "negative pressure" from a "vacuum". The Casimir effect is not evidence of negative pressure in a vacuum. In fact it's typically not even done in a vacuum in the first place, and always includes "positive pressure" in the chamber and "QM force" on both sides of both plates.

 

[Tubbythin]

I just don't see how you can ignore the fact you have 'pressure' in terms of air, "force" in terms of QM and no forms of "negative pressure" or "negative force" in these processes. Just like the wing analogy, all you have is evidence of "less pressure" between the plates and "more pressure" outside of the plates, and a difference between them.

Guth needs "negative pressure" from a "vacuum". The Casimir effect is not evidence of negative pressure in a vacuum. In fact it's typically not even done in a vacuum in the first place, and always includes "positive pressure" in the chamber and "QM force" on both sides of both plates.

Interestingly, there's a Casimir Research School at Leiden. Lets see what it says:

According to quantum electrodynamics, vacuum is not empty at all but filled with particle-antiparticle pairs that emerge out of nothing and vanish back into nothing an instant later. In between the two plates these virtual particles have a lower density than outside. The resulting negative pressure pulls the plates together.

EDIT The url doesn't seem to work... but its there if you look hard enough.
EDIT 2 Click on Casimir's name that's in light blue after clicking on the hyperlink on the first page you go to.

 

[Tubbythin]

Er, ya, experimental verification of repulsion as well as attraction, and other verbal descriptions from anyone who knows anything about QM....

I know a reasonable amount about quantum mechanics (though I still get things wrong on a regular basis). The veification of repulsion as well as attraction is a verification the the pressure is boundary condition dependent (as you have already been told). It does not in any way support your case. Several other people participating in these fora have illustrated that they know a lot about quantum mechanics (considerably more than me)... you are quite obviously not one of them.

http://physicsworld.com/cws/article/news/32380

Notice how he describes the inside gap having "pressure" that does not match the pressure from the outside and therefore the plates are "pushed together"? Did Michael Mozina write that science article too?

You do realise its not exactly a technical article right? I'm also still looking for any sign that anyone agrees with your outright denial of the existence of negative pressure.

 

[sol invictus]

I'm also still looking for any sign that anyone agrees with your outright denial of the existence of negative pressure.

I can't believe this ridiculous argument is still going on. Casimir forces on an object act to squeeze it, and they scale like 1/r^4, where r is the size of the object. In the simple case of two large flat plates, the force is A/d^4, where A is the area and d the distance between the plates. That is the prediction from quantum mechanics, and it has been confirmed by experimental data. Since the force is acting to push the plates together, that's a net negative pressure.

Now, can one interpret that net pressure as the result of a differential between a positive outside pressure and a smaller positive pressure inside? Let's try:

[latex]P_{Casi} = P_{inside}-P_{outside} = -1/d^4 \rightarrow P_{outside} = 1/d^4 + P_{inside} \rightarrow P_{outside}=\infty[/latex]

since d can go to zero and P_inside is greater than 0.

So you have two choices: either claim that empty space has a positive pressure of +infinity, or that the pressure inside is negative. Take your pick.

 

[Tubbythin]

I can't believe this ridiculous argument is still going on. Casimir forces on an object act to squeeze it, and they scale like 1/r^4, where r is the size of the object. In the simple case of two large flat plates, the force is A/d^4, where A is the area and d the distance between the plates. That is the prediction from quantum mechanics, and it has been confirmed by experimental data. Since the force is acting to push the plates together, that's a net negative pressure.

Now, can one interpret that net pressure as the result of a differential between a positive outside pressure and a smaller positive pressure inside? Let's try:

[latex]P_{Casi} = P_{inside}-P_{outside} = -1/d^4 \rightarrow P_{outside} = 1/d^4 + P_{inside} \rightarrow P_{outside}=\infty[/latex]

since d can go to zero and P_inside is greater than 0.

So you have two choices: either claim that empty space has a positive pressure of +infinity, or that the pressure inside is negative. Take your pick.

But that involves maths! You don't expect any plasma cosmologist to do maths do you? Why bother when you can repeatedly post the same image of a poorly labeled diagram from wikipedia and claim that anyone who doesn't agree with you doesn't understand quantum mechanics (and doesn't realise you can describe the Casimir effect using the ideal gas equation)?

 

[Reality Check]

I just don't see how you can ignore the fact you have 'pressure' in terms of air, "force" in terms of QM and no forms of "negative pressure" or "negative force" in these processes. Just like the wing analogy, all you have is evidence of "less pressure" between the plates and "more pressure" outside of the plates, and a difference between them.

I can see it because (unlike you)

• I have attended high school (and university) and so know what the definition of pressure is.
• I can read textbooks to confirm what the definition of pressure is.
• I can understand that the definition of pressure allows for negative pressure.
• I can follow the mathematics that derives that the Casimir effect between 2 parallel plates and gives a negative pressure.
• I can read, especially the papers that actually measure a negative pressure and that the force varies as predicted by the Casimir effect.
• I know that the theory is for a vacuum (no air pressure) and that the experiments are done in vacuum chambers so that the air pressure can be neglected.

ETA: I can also answer questions.

 

[Michael Mozina]

I can see it because (unlike you)
.....
I have attended high school (and university)

You are a brazen liar. All you folks know how to do is smear individuals. When it comes to actual "science", you couldn't beat your way out of a paper bag.

 

[Michael Mozina]

You do realise its not exactly a technical article right?

You do realize this is a pure act of denial on your part, right? That individual expressed the idea perfectly in that paragraph. There's simply a "difference" between the pressure and force applied to both sides of both plates. Call it "pressure", call it VP "force", call it whatever you like, but it *pushes* on *both* sides of *both* plates, more on one side than the other.

I'm also still looking for any sign that anyone agrees with your outright denial of the existence of negative pressure.

I just handed you a perfectly good explanation of this process from the perspective of QM, which you admit isn't your strong suit. You evidently ignored the authors whole article. It expressly explained that this process can cause "repulsion" as well as 'attraction' depending on the specific conditions because that "pressure" you keep talking about is 'pushing" on *both* sides of *both* plates. There is simply a "pressure difference", no different from the wing analogy. There is no evidence that this is anything other than a 'positive pressure' chamber, both at the atomic level *and* at the level of QM. Your denial of these facts won't change them.

 

[Ziggurat]

When it comes to actual "science", you couldn't beat your way out of a paper bag.

You've got no leg to stand on with this claim, Michael. You've demonstrated time and time again that your grasp of freshman physics concepts is tenuous at best, and your math skills (yes, Michael, you need math to actually do any real physics) are apparently nonexistent. But then again, most of us here are talking about science, not "science".

 

[Ziggurat]

There's simply a "difference" between the pressure and force applied to both sides of both plates.

So in other words, you think the pressure on the outside of the plates is infinite, as Sol's post suggested?

 

[Tubbythin]

You are a brazen liar. All you folks know how to do is smear individuals. When it comes to actual "science", you couldn't beat your way out of a paper bag.

Ahem. Do I have to go and link back to the point where you were caught telling a blatant lie?

 

[Michael Mozina]

Michael, if the argument were that simple please explain why bosonic fields result in the plates being pulled together while fermionic fields push the plates apart?
It really is not quite as simple as the Physics World article makes out. I'm sorry you've been mislead by this explanation of the effect.

edd, as much as I like and respect you personally, I have to tell you that this is the single most obvious example of denial I've seen you go for thus far in this thread.

Evidently you don't wish to embrace the QM view of how things function at the subatomic level, but that article is right on the money. I have not been "mislead" by that article or any article since I started this debate before reading either the WIKI presentation of the Casimir effect or this article. This article (and many other papers and articles) demonstrates that the concept of "force" or "pressure" or whatever you wish to call it, must be applied to *both sides* of both plates. There is therefore simply a "pressure difference" between the inside and outside of the plates.

The pressure is negative,

No, the pressure is "greater" on the outside and "less" on the inside. Note that the blue arrows point *towards* (not away from) all the surfaces of both plates.

The VP "pressure" effects all the sides of all plates. It simply "pushes" more on one side than the other. The only thing that is occurring here is a 'pressure difference', exactly like my wing analogy. There is "greater pressure" on the outside of the plates, and "less pressure" on the inside of the plates, but all the sides of all the plates feels "pressure" from atoms in the chamber, and "pressure" from VP's in the chamber. No side of any plate experiences "negative pressure", because no such thing can exist in nature. There is kinetic energy in the chamber, both in the form of atoms vibrating inside the chamber, and at the level of QM.

There is no such thing as "negative pressure in a vacuum". Guth's inflation theory is DOA because it is predicated upon a physical impossibility. No area of any "vacuum" is devoid of "pressure", either at the atomic level (because we can't remove all the atoms), or at the subatomic level. There is always and has always been a "net positive' amount of energy (and pressure) in every vacuum.

 

[Michael Mozina]

Ahem. Do I have to go and link back to the point where you were caught telling a blatant lie?

Why would you personally go out of your way to lie about my education? Are you so insecure that you need to resort to below the belt debate tactics now? How desperate are you anyway?

 

[Tubbythin]

You do realize this is a pure act of denial on your part, right?

No, it isn't. Its from physics world, a broad ranging magazine of the IOP, aimed roughly speaking at a first year undergraduate level.

That individual expressed the idea perfectly in that paragraph. There's simply a "difference" between the pressure and force applied to both sides of both plates. Call it "pressure", call it VP "force", call it whatever you like, but it *pushes* on *both* sides of *both* plates, more on one side than the other.

Just read Sol's post again.

I just handed you a perfectly good explanation of this process from the perspective of QM, which you admit isn't your strong suit. You evidently ignored the authors whole article. It expressly explained that this process can cause "repulsion" as well as 'attraction' depending on the specific conditions because that "pressure" you keep talking about is 'pushing" on *both* sides of *both* plates.

Its not my strong suit in that for someone with a degree in physics who looks at quantum systems on a daily basis, I should be better at it than I am.

There is simply a "pressure difference", no different from the wing analogy. There is no evidence that this is anything other than a 'positive pressure' chamber, both at the atomic level *and* at the level of QM. Your denial of these facts won't change them.

There is no evidence that you have the slightest idea what you are talking about. Look at Zig's definition of pressure again.
What the hell do you mean "at the atomic level *and* at the level of QM"? Are atoms not quantum systems?

 

[Tubbythin]

Ahem. Do I have to go and link back to the point where you were caught telling a blatant lie?

Why would you personally go out of your way to lie about my education? Are you so insecure that you need to resort to below the belt debate tactics now? How desperate are you anyway?

Huh? I have no idea what you're talking about. Your comment has no relation to the comment you are responding to.