Lambda-CDM theory - Woo or not?

[Michael Mozina]

I disagree with you on this point. As I've posted before, if you have some situation like gases in three volumes as:

2 atm | 1 atm | 2 atm

then the dividing walls between each chamber might be pushed together, but the pressures are all positive on both sides of the walls. If the walls move together due to the greater external pressure, then work is done by the outer volumes upon the inner one, and the energy in the centre volume rises.
Michael would be right in his arguments if the above system did represent something like the Casimir case, but it doesn't, and he's wrong.

It most certainly *does* work like that since most experiments take place inside a 1ATM pressurized environment.

There are technically only two ways you're going to get the plates to come together, the way I explained it, or due to EM attraction between the plates. Neither one of these choices is going to help you justify a "negative" pressure in a vacuum.

What *physically* would create a "negative pressure" in a pressurized chamber?

 

[edd]

You guys better keep up a consistent front or the whole show is going to fall apart.

a) that doesn't follow
b) it wouldn't make you right

 

[Michael Mozina]

a) that doesn't follow
b) it wouldn't make you right

It does suggest to me that you guys can't make up your mind or physically explain what's happening. The only way that I could be "wrong" is if the plates themselves exchange carrier particles and "attract" one another in that way. Even still, that would not justify the claim that a "vacuum" contains "negative pressure". In no case does the vacuum chamber achieve a "negative" pressure. At the level of QM, you have a "low" pressure zone between the plates and a "higher pressure" outside of the plates, but nowhere in a pressurized chamber will you find "negative pressure".

 

[edd]

It most certainly *does* work like that since most experiments take place inside a 1ATM pressurized environment.

There are technically only two ways you're going to get the plates to come together, the way I explained it, or due to EM attraction between the plates. Neither one of these choices is going to help you justify a "negative" pressure in a vacuum.

What *physically* would create a "negative pressure" in a pressurized chamber?

Oh I don't know... some kind of effect from second quantisation perhaps?

I would agree that in a sense the Casimir effect is due to EM attraction in that the contribution from virtual photons is the dominant effect, but it's a quantum mechanical effect and not a classical one, and we've explained endlessly why this constitutes a negative pressure. Essentially, the "stuff" between and around the plates does not have the same properties as the real particles to which you are accustomed.

It also certainly doesn't behave like the situation I outlined, regardless of any ambient gas pressure. If you compress a volume of gas, the pressure inside rises and the work you have to do to decrease the volume further increases - the pressure becomes more positive.

In the Casimir effect as the volume becomes compressed the attraction increases and the work the volume does increases - the pressure becomes more negative.

The physical situations could barely be more distinct.

 

[temporalillusion]

What's the upper limit to the difference in pressure outside and inside the plates MM, it's your model so you should be able to give that.

 

[Dancing David]

It most certainly *does* work like that since most experiments take place inside a 1ATM pressurized environment.

There are technically only two ways you're going to get the plates to come together, the way I explained it, or due to EM attraction between the plates. Neither one of these choices is going to help you justify a "negative" pressure in a vacuum.

What *physically* would create a "negative pressure" in a pressurized chamber?

Ahm yes but then the pressure between the plates will increase as the distance between them decreases.

Yes?

And what is the pressure difference between 2 ATM and 1 ATM?

 

[The Man]

Really? You designed and built the computer I put together myself from parts?

Oh, parts you made yourself?

Are you're trying to claim astronomers built the microprocessor because it was developed during the Apollo missions?

No, just scientist and engineers who knew what they are talking about, a trait that seems to elude you.

 

[Michael Mozina]

Oh I don't know... some kind of effect from second quantisation perhaps?

In physical terms, what does that mean to you?

I would agree that in a sense the Casimir effect is due to EM attraction in that the contribution from virtual photons is the dominant effect, but it's a quantum mechanical effect and not a classical one,

It really makes little difference whether it's a "classical" effect or not.

and we've explained endlessly why this constitutes a negative pressure.

You've *alleged* endlessly that this constitutes a "negative pressure" but the whole process takes place inside of a pressurized, room temperature chamber in most cases.

Essentially, the "stuff" between and around the plates does not have the same properties as the real particles to which you are accustomed.

It really doesn't matter. The only thing that actually matters is that all sides of all plates experience this phenomenon, the outside simply experiences more of it.

It also certainly doesn't behave like the situation I outlined, regardless of any ambient gas pressure. If you compress a volume of gas, the pressure inside rises and the work you have to do to decrease the volume further increases - the pressure becomes more positive.

How can you just overlook the small fact that the chamber *has positive pressure in it*?

In the Casimir effect as the volume becomes compressed

No. The *volume* of the chamber does not change. Only the distance between the plates changes.

the attraction increases

Even *if* there is an "attraction" between the two plates, that is not a justification of a "negative pressure" in a "vacuum". You're still ignoring the key issue here. The *pressure* in the chamber is *consistently positive*. Whatever "attraction" might take place between the two plates would be directly related to an atomic process of some sort that would have absolutely nothing to do with the "pressure" in the chamber.

 

[edd]

It does suggest to me that you guys can't make up your mind or physically explain what's happening.

I think I've been pretty consistent in my approach to this. I'm not going to compromise my position out of some misplaced "the enemy of my enemy is my friend" sentiment, although despite the disagreement here I have much respect for Reality Check's patience in dealing with you, and for his generally good grasp of much of the relevant physics.

It's mildly unfortunate if this leads you to be more mistrustful of the accepted physics of the Casimir effect, but I suspect that even if we happened to agree 100% we would not be significantly closer to educating you.

 

[Michael Mozina]

Oh, parts you made yourself?

No, I bought the CPU, motherboard and memory from a "computer store", not an astronomer.

No, just scientist and engineers who knew what they are talking about, a trait that seems to elude you.

Unlike my computer, your inflation genie has no value in my life whatsoever. Unlike my computer your beloved "dark energy" is a no show in any consumer product. Unlike my computer you SUSY particles never show up in real life. You're comparing a computer that functions on a daily basis to a dead inflation deity? Get real.

 

[edd]

No. The *volume* of the chamber does not change. Only the distance between the plates changes.

In the physical setup I posted above I intended it to be read as something like a three-chambered piston. The spaces on either side of each plate are sealed, although the plates can move. Thus there are three separate volumes there and the relevant one to the discussion is the middle one between the two plates.

Even *if* there is an "attraction" between the two plates, that is not a justification of a "negative pressure" in a "vacuum". You're still ignoring the key issue here. The *pressure* in the chamber is *consistently positive*. Whatever "attraction" might take place between the two plates would be directly related to an atomic process of some sort that would have absolutely nothing to do with the "pressure" in the chamber.

On the contrary, you're ignoring the key point, which is about the change in energies and how this relates to the pressure. As I've said before this is especially crucial given the context of this in cosmological negative pressure sources of gravity.

 

[Michael Mozina]

I think I've been pretty consistent in my approach to this.

You have both been *extremely* consistent but not consistent with each other. I see this a lot in other conversations with other types of creationists. It's very common actually.

I'm not going to compromise my position out of some misplaced "the enemy of my enemy is my friend" sentiment,

I'm not asking you to do that. I'm asking you to change your position based on logic and common sense. The plates can "attract" one another perhaps, and the plates can be "pushed together" based on a pressure difference between the outside and inside of the plates, but those are the only two logical choices because the chamber has "pressure" in it. There can be no area that actually has "negative pressure" in it, even if the plates attract one another in a *positive pressure* environment.

although despite the disagreement here I have much respect for Reality Check's patience in dealing with you, and for his generally good grasp of much of the relevant physics.

I actually have more respect for your style.

It's mildly unfortunate if this leads you to be more mistrustful of the accepted physics of the Casimir effect, but I suspect that even if we happened to agree 100% we would not be significantly closer to educating you.

You can't "educate" me by throwing garbage my way. While it is entirely "possible" that there is an attraction going on between the plates as you seem to be suggesting, this would in no way justify Guth's claim about a vacuum having "negative pressure". All it might demonstrate is that one "near singularity", might be attractive to another one. So what? In no way does that justify Guth's claim that a vacuum has "negative pressure".

The bottom line here is that all vacuums, even the very best ones we can create, and the best ones in space have some amount of atoms in them, and some amount of 'pressure'. There is no physical possibility of achieving a "zero" pressure in any vacuum, let alone a "negative" one.

 

[edd]

I'm not asking you to do that. I'm asking you to change your position based on logic and common sense. The plates can "attract" on another perhaps, and the plates can be "pushed together" based on a pressure difference between the outside and inside of the plates, but those are the only two logical choices because the chamber has "pressure" in it. There can be no area that actually has "negative pressure" in it, even if the plates attract one another in a *positive pressure* environment.

OK, if it were an entirely positive pressure environment and we sealed the volume between the two plates (something not done experimentally because I suspect the friction from such seals makes measuring the force difficult, and the QM understanding of the Casimir effect doesn't require that volume to be sealed), then as the plates drew closer and the volume between them shrank, the stuff between them gets compressed more so the pressure should go up, right? Would you agree that's a good prediction from your theory of what is going on in the Casimir effect?

 

[The Man]

No, I bought the CPU, motherboard and memory from a "computer store", not an astronomer.



Unlike my computer, your inflation genie has no value in my life whatsoever. Unlike my computer your beloved "dark energy" is a no show in any consumer product. Unlike my computer you SUSY particles never show up in real life. You're comparing a computer that functions on a daily basis to a dead inflation deity? Get real.

I am not an astronomer and none of those concepts you mentioned are mine. I am comparing a ‘computer that functions on a daily basis’ along with the understanding of the people, technology and science that make it possible to your inability to comprehend what you read and your understanding that apparently fails on a daily basis.

 

[Michael Mozina]

On the contrary, you're ignoring the key point, which is about the change in energies and how this relates to the pressure. As I've said before this is especially crucial given the context of this in cosmological negative pressure sources of gravity.

Let me try it this way for you edd. *If* you are correct, and there is an attractive "force" between the plates, all this would demonstrate is that atoms attract other atoms. In no way would that justify the claim that a vacuum contains "negative pressure". The very most you might be able to demonstrate is that the "force" on the plates is due to an attraction between the plates. That would not demonstrate a "negative pressure in a vacuum". It would only demonstrate an attractive quality between two mass objects. So?

Guth's inflating singularity thing requires "negative pressure" from a "vacuum". That is quite unlike an attraction to another object outside of the singularity. How can you not see this distinction?

 

[Michael Mozina]

I am not an astronomer and none of those concepts you mentioned are mine. I am comparing a ‘computer that functions on a daily basis’ along with the understanding of the people, technology and science that make it possible to your inability to comprehend what you read and your understanding that apparently fails on a daily basis.

I'm competent enough with my abilities to comprehend technology to be able to own my own software company, assemble computers, etc. There is however a distinct difference between something I can "understand" by putting it together piece by piece and turning it on, vs. an idea I must accept on "blind faith", like the dead inflation deity. I can see my computer work every day, whereas "dark energies" have never done anything useful for me whatsoever. SUSY particles are also a no show in any controlled experiment. There is no comparison between a tangible thing like a computer and a purely "made up" item like inflation or dark energy.

 

[Michael Mozina]

OK, if it were an entirely positive pressure environment and we sealed the volume between the two plates (something not done experimentally because I suspect the friction from such seals makes measuring the force difficult, and the QM understanding of the Casimir effect doesn't require that volume to be sealed), then as the plates drew closer and the volume between them shrank, the stuff between them gets compressed more so the pressure should go up, right?

The pressure probably would go up and that pressure would eventually offset whatever "attraction" might be occurring between the plates. You'd end up at a point of equilibrium. The reason they go together is because the ends are *not* sealed and because the "pressure' between the plates therefore does not increase when the plates move toward one another.

 

[edd]

Let me try it this way for you edd. *If* you are correct, and there is an attractive "force" between the plates, all this would demonstrate is that atoms attract other atoms. In no way would that justify the claim that a vacuum contains "negative pressure". The very most you might be able to demonstrate is that the "force" on the plates is due to an attraction between the plates. That would not demonstrate a "negative pressure in a vacuum". It would only demonstrate an attractive quality between two mass objects. So?

I wouldn't claim that the negative pressure from the vacuum in the Casimir effect is the same as a cosmological constant or currently-dominating dark energy, and certainly not the same as whatever was responsible for inflation.

However, the theory that accurately predicts the behaviour in the Casimir effect amongst a wealth of other experimental observations is pretty clear in explaining it in terms of something that reduces in energy as its volume decreases, and this is the kind of behaviour needed for dark energy or for inflation.

Guth's inflating singularity thing requires "negative pressure" from a "vacuum". That is quite unlike an attraction to another object outside of the singularity.

In this case, I believe there is a misunderstanding on your part on the role the negative pressure plays. The force from the pressure (as in the F in P=F/A) is not the force that's relevant. The gravitational force from the energy of whatever has this negative pressure is the important thing, and this is distinct from the pressure.

 

[Michael Mozina]

I wouldn't claim that the negative pressure from the vacuum in the Casimir effect is the same as a cosmological constant or currently-dominating dark energy, and certainly not the same as whatever was responsible for inflation.

But there is no "negative pressure" involved in this process. At best case you have "positive pressure" being offset (overcome) by the force of attraction between the plates. You would end up with a "positive pressure" environment, and an "attractive force" between mass objects, and nothing even remotely like "negative pressure in a vacuum".

However, the theory that accurately predicts the behaviour in the Casimir effect amongst a wealth of other experimental observations is pretty clear in explaining it in terms of something that reduces in energy as its volume decreases, and this is the kind of behaviour needed for dark energy or for inflation.

Actually, no. In that case, the behavior would be an attraction between objects of mass, and it would not be at all like DE or inflation. It would only serve to "pull things together", not spread them apart.

In this case, I believe there is a misunderstanding on your part on the role the negative pressure plays. The force from the pressure (as in the F in P=F/A) is not the force that's relevant. The gravitational force from the energy of whatever has this negative pressure is the important thing, and this is distinct from the pressure.

There is nothing here that has "negative pressure". At best case there is an attractive force between metallic objects and in no way does that justify Guth's claim about a negative pressure in a vacuum. That is not a "negative pressure in a vacuum", that is an "attraction of objects to other objects" and would have the reverse effect of what you are trying to achieve. It would act to "pull things closer together", not spread them apart.

 

[The Man]

I'm competent enough with my abilities to comprehend technology to be able to own my own software company, assemble computers, etc. There is however a distinct difference between something I can "understand" by putting it together piece by piece and turning it on, vs. an idea I must accept on "blind faith", like the dead inflation deity. I can see my computer work every day, whereas "dark energies" have never done anything useful for me whatsoever. SUSY particles are also a no show in any controlled experiment. There is no comparison between a tangible thing like a computer and a purely "made up" item like inflation or dark energy.

Again that “tangible thing like a computer” is only made possible by people with a better understanding then you just putting the pieces they made together. Similarly you are tiring to put your own pieces together about QM and cosmology that you certainly do not seem to understand and as a result your pieces just don’t work. If you are willing to put together the computer pieces that you got from someone else, because they work and those people understood what they were doing, to get that computer to work when you turn it on, then why not do the same with QM and cosmology? Two of the pieces you have already been given are zero point energy and negative pressure, but since you do not understand them and simply refuse to accept that other people do or that they are even possible, your "blind faith" construct simply does not work.