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

[Michael Mozina]

What are you laughing at, yourself? Expansion can occur without "negative pressure in a vacuum" as the sun demonstrates every single day dude.

 

[Tubbythin]

Only because you'd have to say 'it's wrong too' if it wasn't "vague" from your perspective. Funny how the blue stuff is everywhere in the chamber and there is simply "less of it" between the plates than on the outside. That's not very "vague" if you ask me.

Hmm. "Foamy bubbles". And "blue stuff". I think you've rather excellently proved my point.

 

[Michael Mozina]

Hmm. "Foamy bubbles". And "blue stuff". I think you've rather excellently proved my point.

The only thing you've demonstrated is that you have a problem with *BOTH* diagrams not just one of them. That's actually the third one I presented for you, but the other one had nothing to do with Wiki as I recall.

It's not just A diagram you have a problem with.

 

[Tubbythin]

The only thing you've demonstrated is that you have a problem with *BOTH* diagrams not just one of them. That's actually the third one I presented for you, but the other one had nothing to do with Wiki as I recall.

It's not just A diagram you have a problem with.

I'm sure there is more than one diagram in wikipedia that is wrong. And more than one that is vague. But can you tell me what the "foamy bubbles" are meant to be? If so, why are you referring to them as "foamy bubbles" (I don't recall Casimir ever including anything about "foamy bubbles" in his calculation)? If not, then the diagram is clearly to vague to even assess whether it is right or wrong.
The previous diagram, on the other hand, I have given a clear reason why it is wrong. A reason that you have not once attempted to address.

 

[GeeMack]

The only thing you've demonstrated is that you have a problem with *BOTH* diagrams not just one of them. That's actually the third one I presented for you, but the other one had nothing to do with Wiki as I recall.

It's not just A diagram you have a problem with.

I think his point was that real scientists don't engage in looks-like-a-bunny science for the very reason you've demonstrated so often and so clearly here. The reason being that it has such a high likelihood of resulting in the kind of complete failure you've achieved here.

 

[Michael Mozina]

I'm sure there is more than one diagram in wikipedia that is wrong. And more than one that is vague. But can you tell me what the "foamy bubbles" are meant to be?

http://en.wikipedia.org/wiki/Quantum_foam

 

[Michael Mozina]

Care to explain what those blue regions are suppose to represent in that second diagram from your perspective?

 

[ben m]

Expansion can occur without "negative pressure in a vacuum" as the sun demonstrates every single day dude.

First of all, thank you for illustrating my point in such a timely fashion: you really don't seem to know the difference between "expansion" (da/dt), the rate of increase of the size of the Universe, and "acceleration" (d^2a/dt^2), the rate of increase of that rate. Expansion and acceleration are totally different things; Hubble observed expansion (but neither acceleration nor deceleration); Permutter and Riess et. al. expected to see deceleration of the expansion but instead saw acceleration.

Acceleration occurs in many small systems: nuclear bombs, internal combustion engines, my lungs, piezoelectric crystals, ice, supernovae, and so on---mediated by short range forces like the weak nuclear force, the strong nuclear force, electromagnetism, or Pauli exclusion. The observed long-range acceleration of galaxies is NOT driven by the strong nuclear force, nor the weak nuclear force, nor electromagnetism. The only thing left is gravity.

Fortunately gravity (i.e. GR) is very good at producing this acceleration---indeed, at exactly this observed, isotropic, weak-equivalence-obeying acceleration---if there is a cosmological constant (or something much like it.)

 

[ben m]

Evidently you and ben. Einstein's constant was intentionally put there to explain a universe that neither expanded nor contracted.

Maybe you will fill in my blank eventually. The NET cosmic acceleration in Einstein's equation is zero. This comes from the sum of two terms. The mass term obviously produces deceleration. The cosmological constant term produces ________. Einstein said, then, that deceleration + ______ = zero.

Fill in the blank already.

 

[Reality Check]

How about this one?

http://upload.wikimedia.org/wikiped...bles.svg/300px-Casimir_plates_bubbles.svg.png

Notice the blue foamy bubbles are bigger on the outside than the inside? How about that diagram? Is it right or wrong?

It is right as a illustration of "Casimir forces on parallel plates" as the caption states. But the caption does not state what the blue foamy bubbles are. My guess - vacuum fluctuations considered as virtual particles.

Of course it is also wrong as far as you are concerned. You only know about gas pressure. There is no indication in the diagram that the bubbles are moving or that they are impacting the plates.

Also:

1. The diagram has nothing to do with the calculation of the pressure exerted by the Casimir effect.
   That calculation results in values of pressure that are negative. Scientists call this negative pressure.
2. The diagram has nothing to do with the measurement of the pressure exerted by the Casimir effect in experiments. Those measurement measure negative pressure.

 

[Reality Check]

A high school physics assignment for Micheal Mozina

A high school physics assignment for you:

First asked 3 February 2010
Calculate the pressure caused by the big blue arrows on the left hand plate. Assume that the force is F₁.
Calculate the pressure caused by the small blue arrows on the left hand plate. Assume that the force is F₂.
Calculate the pressure caused by the big blue arrows on the right hand plate. Assume that the force is F₁.
Calculate the pressure caused by the small blue arrows on the right hand plate. Assume that the force is F₂.

Remember that a force that points in the opposite direction to another has an opposite magnitude, e.g. if the first force has a positive value then the second force has a negative value. So you will have to set a convention about how to determine this, e.g. forces pointing to the right are positive.
N.B. Apply the same convention to both plates.

Your math skills should be up to this as it just requires the basics.

 

[Perpetual Student]

Originally Posted by Michael Mozina
Let me ask you a philosophical question PS. What scientific theory rises or falls on my personal math skills? Why would it be necessary for me personally to do anything other than provide the relevant scientific papers and sources on various scientific topics? When debating young earth creationists, I don't make it a point to go out and dig up various fossils myself and carbon date them personally in my garage. I don't try to explain every mathematical formula in a carbon dating paper to a "disbeliever". Even *if* I had a personal inability to explain the math to the ''disbeliever", the validity of the science and the math would not rise or fall on my personal math skills.

What difference does it make if I personally bark math on command around here? What would be the point of doing that when everyone knows that they're simply looking for some flaw to criticize my personal math skills. It would detract from the topic, and it would do nothing to resolve the basic debate. What's the point of me barking math when Einstein did that already in GR, Alfven did that in MHD theory and far better mathematicians have done that for every scientific topic under the sun?

Let's turn the tables here and suppose I was defending the validity of carbon dating techniques to a bunch of young earth creationists. Would you still think my personal math skills were relevant in some way?

If you were debating the magnitude of voltage and impedance in a capacative circuit you would look at equations like:

vG = (vR² + vC²)½

and

XC = 1/2πfC

You would then take measurements to confirm your theory and see who is right. I don't see this as a mere demonstration of math skills; it is simply the only way to communicate about RC circuits. Similarly, regarding cosmology, you are in an arena here that involves mathematical equations. How else can you have a discussion?

You have no response for my point above. You see, in this Casimir effect debate, instead of discussing the mathematics of the issue, you rely on an artist's imperfect cartoon meant as a didactic tool for laypeople. Are you seriously presenting this as evidence of something? An artist's cartoon?
What about sol's question:

[latex]$({\dot a \over a})^2 = {8 \pi G \over 3} (\rho_m + \rho_\Lambda) - {1 \over a^2}$[/latex],

and:

[latex]$T_{\mu \nu}$[/latex]

Are you going to respond to those questions or not? This is modern physics, utterly dependent on mathematics, it's not the touchy/feely picture word of the Hittites.

 

[temporalillusion]

For the love of God MM---what other pressure would it have? The CC is in there as a constant energy density (LOOK AT THE EQUATION YOURSELF) with dE/dV > 0 (TAKE THE DERIVATIVE YOURSELF). That's the beginning, the middle, and the end of what we mean by "negative pressure", as we've been saying since day one. You don't need to look for tea leaves in the literature to figure it out.

Any other meaning you give to the word "pressure"---"momentum transfer from particles hitting a wall" etc.---is utterly irrelevant in the context of gravity.

I think this is one basic difference between what you guys are saying with the math and what MM has modeled in his mind. Every single time negative pressure and vacuum come up MM says there is no such thing as a perfect vacuum, which makes me think he's got a kinetic atoms bashing or EM pushing model in his head. When he says vacuum and you say vacuum I don't think you are syncing up.

Like in the Lambda-CDM thread we were discussing what the maximum theoretical pressure would be in an Casimir effect experiment as you brought the plates closer together and he said 1 atmosphere...

 

[Tubbythin]

http://en.wikipedia.org/wiki/Quantum_foam

Now I'm not saying that there is no correspondence whatsoever between the ideas of quantum foam and the Casimir effect, but I don't really see how it'd be relevant in the Casimir diagram:

Quantum foam, also referred to as spacetime foam, is a concept in quantum mechanics, devised by John Wheeler in 1955. The foam is supposedly the foundations of the fabric of the universe,[1] but it can also be used as a qualitative description of subatomic spacetime turbulence at extremely small distances of the order of the Planck length.

The whole point is that it is the long wavelengths that are not present between the plates. So in a typical experiment that is things the order of a micrometre. That makes a difference in scale between the relevant wavelengths and the quantum foam of ~ 10²⁹ ie that's a factor of a hundred billion billion.

For what its worth (not very much IMHO), the wikipedia article also says:

The "foamy" spacetime would look like a complex turbulent storm-tossed sea.

which is nothing whatsoever like the wikipedia diagram.

 

[Tubbythin]

Care to explain what those blue regions are suppose to represent in that second diagram from your perspective?

No. That was the whole point. I have no idea. And there's very little indication given with the picture.

 

[Michael Mozina]

Now I'm not saying that there is no correspondence whatsoever between the ideas of quantum foam and the Casimir effect, but I don't really see how it'd be relevant in the Casimir diagram:

And therein lies the problem......

 

[Michael Mozina]

You'll need to be patient PS, it's slamming at work. I'll get to your post.

I think it's more than a little unfair to refer to an artists drawing or rendition as a "cartoon". Both diagrams correctly demonstrate the EM forces from the perspective of QM. Sometimes a drawing can give a lot more accurate information than an oversimplified math formula PS!

 

[Michael Mozina]

First of all, thank you for illustrating my point in such a timely fashion: you really don't seem to know the difference between "expansion" (da/dt), the rate of increase of the size of the Universe, and "acceleration" (d^2a/dt^2), the rate of increase of that rate.

Oh boloney. The bottom line is that Einstein's introduction of his constant was not intended (by him) to generate either expansion(velocity) or acceleration, but rather to to create a "static" universe that neither expanded or contracted. He made a mistake in the original paper, and it was *NOT* stable as written, but that was his original intent.

http://www.google.com/search?q=static+universe+einstein

 

[ben m]

Oh boloney. The bottom line is that Einstein's introduction of his constant was not intended (by him) to generate either expansion(velocity) or acceleration, but rather to to create a "static" universe that neither expanded or contracted.

And again, for the third time, the answer is the answer to my fill-in-the-blank question. I didn't ask that to distract you, I asked it so you'd fill in the blank and understand the answer.

Have you filled in the blank yet?

 

[Michael Mozina]

I think this is one basic difference between what you guys are saying with the math and what MM has modeled in his mind.

No, in this case there is a difference between the mathematical model (a highly oversimplified math formula) that they are using, and the actual physics that occurs inside the chamber.

The "negative pressure" found in their math formula is an entirely "relative" number (to one surface of the plate), not an "absolute" measurement of pressure in the chamber. That's the basic problem in a nutshell.

It's just like that wing analogy I used earlier. Yes, we could create a math formula to describe lift that was relative to the top side of the wing and used a "negative pressure" term in the formula. *NO*, that "minus sign" doesn't really mean that there is "negative pressure" on the top of the wing. It means that there is *LESS PRESSURE* on the top of the wing than the pressure below the wing. Likewise in this analogy, the mathematical formula relates to a single side of the plate, and therefore it has a "minus sign" in the formula. That has nothing to do with the absolute pressure in the chamber due to atoms, *AND* the EM field, both of which put "pressure" on every side of every plate, just more pressure on some sides than on others. That is why the effect is a *GEOMETRICALLY* driven process and can create both attraction *AND* repulsion between the plates!