Can pressure be negative?

[Ziggurat]

Sure. Crank up the charge between two objects in a vacuum and you'll get an increase in kinetic energy between the objects in the vacuum.

That change has nothing to do with changes in volume. I want to know if the energy of a vacuum can increase because the volume of the vacuum increased. Yes or no.

And there's no point in calling it "kinetic energy". That's your own little irrelevant fetish.

 

[Tubbythin]

Ya, but it's also inseparably tied to physics. Unfortunately none of your claims can be demonstrated in a lab.

a) You're wrong. b) Science does not need to be demonstrated in a lab. The lab is a structure of human convenience. The Universe was not designed for human convenience.

It's therefore a complete act of faith on the part of the 'believer' and anyone that questions your faith in the unseen (in the lab) is attacked as an individual. Since you can't run around calling folks "evil" or a "spawn of satan" in your quaint little religion, they are called a "crank' or a "crackpot", or you degrade their math skills, virtually execute them, virtually silence them, or all the above in your case.

Mozina the scientis 0-8 Mozina the pathetic

 

[ben m]

What answer? What one thing did you physically intend to add to a pure vacuum (containing no kinetic energy of any kind at all) to create a "negative pressure vacuum" Ben?

Quantum fluctuations.

They have positive energy. Most of them don't travel long distances to push on (Casimir-like effects excepted), so their kinetic pressure is zero. They don't behave like a gas that bumps into things and exerts forces on them.

What they do have is mass density. What does GR tell you is the gravitational pull of an incompressible, undilutable mass density filling a large region of space?

ETA: (I know the answer already---if your answer disagrees with mine, in what way do you think my GR is wrong? )

 

[Michael Mozina]

Why must others prove you wrong?...Why are you so incapable of proving yourself right.

You know.....

In "physics", and in science in general, it is typically up to the person making the claim to demonstrate their claim. I can't 'disprove' negative pressure in a vacuum does something to plasmas, that's you job. I *CAN* demonstrate that EM fields can cause plasma to accelerate over time. They can also heat plasmas to millions of degrees. According to your redshift interpretation of preference, we observe accelerating high temperature plasmas in space. I can in fact demonstrate in the lab that EM field can "cause" both high temperature plasma and accelerating plasmas. If you can't do that with your mythical magical negative pressure god, why should I bow your your impotent deity, or your peer pressure? Why is it my fault that your negative vacuum pressure sky deity is a no show in the lab?

 

[Michael Mozina]

The Casimir effect hasn't failed the physics test.

I never claimed it did. That's your strawman. See the difference?

It doesn't require faith because it can be demonstrated quantitatively and objectively (one of the essential separators between science and religion).

What does have to do with Guth's magic negative pressure in a vacuum entity?

All that demonstrates is that all "vacuums" have both atoms and other subatomic carriers of kinetic energy. So what? That kinetic energy is *exactly* what precludes you from ever achieving a "negative pressure" in a vacuum. You can't even remove all the atoms in a vacuum, let alone neutrinos or standing EM waves and photons.

The limit of pressure in a vacuum is now and forever will be a number slightly higher than zero. You'll never actually reach zero of course because there will always be some residual kinetic energy in the vacuum. In no cause however can you achieve a "negative pressure'. No atoms or other moving particles in the vacuum, no pressure.

 

[Tubbythin]

In "physics", and in science in general, it is typically up to the person making the claim to demonstrate their claim. I can't 'disprove' negative pressure in a vacuum does something to plasmas, that's you job.

This thread is about negative pressure. It contains a number of links to articles on negative pressure.

I *CAN* demonstrate that EM fields can cause plasma to accelerate over time. They can also heat plasmas to millions of degrees. According to your redshift interpretation of preference, we observe accelerating high temperature plasmas in space. I can in fact demonstrate in the lab that EM field can "cause" both high temperature plasma and accelerating plasmas.

But science is a quantitative subject and you have no quantitative evidence that one thing is the other.

If you can't do that with your mythical magical negative pressure god, why should I bow your your impotent deity, or your peer pressure? Why is it my fault that your negative vacuum pressure sky deity is a no show in the lab?

Mozina the scientist 0-13 Mozina the pathetic

Oh dear.

 

[Perpetual Student]

Let's say Mozina is correct and the best vacuum pressure that can be reached in a lab is some value, say p_lv.

Now, looking at the equation

[latex] \dfrac{F_c}{A} = - \dfrac{(hbar)c\pi^2}{240a^4}[/latex]

we can see that as the variable a (the distance between the two plates) gets smaller the pressure becomes arbitrarily large. When a is very large we can say the pressure is the same on both the inside and outside of the plates as the value of [latex]\dfrac{F_c}{A}[/latex] approaches zero. So, no matter what the magnitude of p_lv is (we can assume the equation above treats it as zero), it has no bearing on the outcome of the experiment since it is not a variable. There is no other explanation that the pressure inside the plates becomes an arbitrarily large negative value since p_lv is a fixed positive value. Hence, negative pressure exists inside those plates.
Paying attention Mozina?

Mozina, why have you not addressed this? The equation used was developed on theoretical grounds and has been *empirically* demonstrated in a lab.
If there were no negative pressure, what is the explanation for the experimental confirmation of the equation?

 

[Michael Mozina]

a) You're wrong. b) Science does not need to be demonstrated in a lab. The lab is a structure of human convenience. The Universe was not designed for human convenience.

Ya, and in terms of empirical physics, religions aren't typically designed for the lab either. That's the problem with all 'acts of faith in the unseen'. You don't HAVE to demonstrate your case empirically to "have faith' in the unseen, and apparently that's all you've got, "faith".

Mozina the scientis 0-8 Mozina the pathetic

I've been called worse by "believers" in the "unseen in the lab". Your personal put downs are actually not very creative and rather pathetic compared to your average religious oriented website.

If an appeal to popularity shrouded in a personal put down is the best you've got, you're evidently quite desperate.

 

[ben m]

All that demonstrates is that all "vacuums" have both atoms and other subatomic carriers of kinetic energy. So what? That kinetic energy is *exactly* what precludes you from ever achieving a "negative pressure" in a vacuum. You can't even remove all the atoms in a vacuum, let alone neutrinos or standing EM waves and photons.

You're still thinking of the pressure that occurs when particles bump into things and push on them. Why? You're ignoring gravitation. Why? Do you think gravity doesn't exist? Do you think kinetic energy does not "source" gravity?

 

[Tubbythin]

What does have to do with Guth's magic negative pressure in a vacuum entity?

This is a thread about negative pressure.

All that demonstrates is that all "vacuums" have both atoms and other subatomic carriers of kinetic energy.

It deomonstrates nothing of the sort.

So what? That kinetic energy is *exactly* what precludes you from ever achieving a "negative pressure" in a vacuum.

No it isn't. You're the only person claiming this in, as far I am aware, the entire world. I suppose that makes you pretty unique.

You can't even remove all the atoms in a vacuum, let alone neutrinos or standing EM waves and photons.

There is absolutely no need to. None whatsoever.

The limit of pressure in a vacuum is now and forever will be a number slightly higher than zero.

Nope, that is the limit of gas pressure. There are other types of pressure than gas pressure.

You'll never actually reach zero of course because there will always be some residual kinetic energy in the vacuum.

Except for the fact that vacuum energy produces negative pressure.

In no cause however can you achieve a "negative pressure'.

Yes you can, through vacuum pressure. You can deny it all you want. You can make utterly irrelevant claims about gas pressure all you want. You can throw in as many stupid phrases related to magic and religion and impotence as you want. It doesn't matter. You're still plain old wrong.

No atoms or other moving particles in the vacuum, no pressure.

No atoms or other moving particles in the vacuum then you have the pressure due to the vacuum energy... which is negative.

ETA:
Mozina the scientist 0-14 Mozina the pathetic.

 

[Tubbythin]

Ya, and in terms of empirical physics, religions aren't typically designed for the lab either. That's the problem with all 'acts of faith in the unseen'. You don't HAVE to demonstrate your case empirically to "have faith' in the unseen, and apparently that's all you've got, "faith".

Could you please reconstruc the above paragraph in a form that actually makes sense. Thanks.

I've been called worse by "believers" in the "unseen in the lab". Your personal put downs are actually not very creative and rather pathetic compared to your average religious oriented website.

I'm not trying to put you down. I'm highlighting all the examples where you use stupid, unneccessary and/or pathetic words instead of making a scientific argument.

If an appeal to popularity shrouded in a personal put down is the best you've got, you're evidently quite desperate.

It wasn't an appeal to popularity or a personal putdown. I'm just keeping track of all the cases where you choose to use stupid, unneccessary and/or pathetic words instead of making a scientific argument.

 

[Michael Mozina]

That change has nothing to do with changes in volume. I want to know if the energy of a vacuum can increase because the volume of the vacuum increased. Yes or no.

I'm getting the distinct feeling that this is a loaded question.

Let's assume the vacuum contains "kinetic energy' (sorry you'll have to learn to deal with physics) in particle form (including photons), and somehow you managed to completely seal your special vacuum from any additional inputs of kinetic energy from outside of the vacuum. It's a physical impossibility of course, but we'll assume you did it somehow. If you then simply increased the volume of the container/vacuum, the particles would "spread out' and become "less dense" and the pressure (quantum and otherwise) would decrease inside of the vacuum.

If however particle kinetic energy is allowed to enter the vacuum from outside of the vacuum and simply fills the vacuum with more kinetic energy, then the increase in volume would result in more energy inside that increased volume of space.

And there's no point in calling it "kinetic energy". That's your own little irrelevant fetish.

Sorry but get over it. You'll have to accept the concept of particle kinetic energy sooner or later. Why else did you figure that temperature affects pressure in an ordinary vacuum?

 

[Tubbythin]

I'm getting the distinct feeling that this is a loaded question.

Let's assume the vacuum contains "kinetic energy'

It doesn't.

(sorry you'll have to learn to deal with physics) in particle form (including photons),

Photons don't have kinetic energy.

and somehow you managed to completely seal your special vacuum from any additional inputs of kinetic energy from outside of the vacuum. It's a physical impossibility of course, but we'll assume you did it somehow. If you then simply increased the volume of the container/vacuum, the particles would "spread out' and become "less dense" and the pressure (quantum and otherwise) would decrease inside of the vacuum.

What particles?

If however particle kinetic energy is allowed to enter the vacuum from outside of the vacuum and simply fills the vacuum with more kinetic energy, then the increase in volume would result in more energy inside that increased volume of space.

He didn't ask about whatever you're trying to explain here.

Sorry but get over it. You'll have to accept the concept of particle kinetic energy sooner or later. Why else did you figure that temperature affects pressure?

He's far more familiar with the concept of temperature and pressure than you are. For example he doesn't seem to think that everything can be described by the ideal gas equation even when the sytem in question bears no resemblance to an ideal gas.

 

[Michael Mozina]

Mozina, why have you not addressed this?

Um, why should I answer your personal questions among the hundreds I receive every single day, when you personally gloat over the fact that you have me on ignore? How would you even see my response?

FYI, I HAVE addressed your question many times now by pointing out that your formula is arbitrarily. It's using a *RELATIVE* number (to one side of the plates) that provides you with a relatively LOWER pressure between the plates vs. the higher pressure outside of the plates. It's like asking me why a math formula that calculates pressure relative ONLY to the top of the wing comes up with a MINUS sign in front of the formula! It's a *RELATIVE* number.

Your formula is also fundamentally flawed because there is a physical limit to the 'flatness' you can expect to achieve from real atoms, therefore the effect isn't "infinite' as your formula implies. Pretty much all your favorite math formulas are usually 'idealized' and they tend to fall apart at the actually level of atoms and subatomic particles. Zig's still convinced it's an infinite effect. How about even showing it comes CLOSE to that number in real life?

 

[Michael Mozina]

It doesn't.

Name one vacuum experiment that was ever devoid of all neutrinos? How about one vacuum devoid of all atoms? Baloney it doesn't.

Photons don't have kinetic energy.

Of course they do. The fact you would even say something like this is simply sad IMO. I need to get some coffee and take a break for a bit. This place does take it out of me after awhile, especially when I see intelligent folks like yourself make silly statements like that.

 

[ben m]

Number of MM posts acknowledging gravity: 0

 

[Michael Mozina]

You're still thinking of the pressure that occurs when particles bump into things and push on them. Why? You're ignoring gravitation.

Are you claiming that gravity is a 'pressure' rather than a "curvature of spacetime"?

 

[edd]

No Michael. It's been explained before. Pressure contributes to gravity. It is not the force from P=F/A that contributes to the cosmological importance of negative pressure - it's the gravitational effect that the pressure has independently of that. Thinking otherwise is like thinking the universe expanded because of it was hot and the matter in it has a positive pressure, which is a common misunderstanding.

Not just mass sources gravity - energy does, and the pressure the energy or matter has is a contributing factor.

I'll probably leave the previous stuff about the big bang, it's too much of a derail here. Fork the thread if you wish.

 

[rwguinn]

No Michael. It's been explained before. Pressure contributes to gravity. It is not the force from P=F/A that contributes to the cosmological importance of negative pressure - it's the gravitational effect that the pressure has independently of that. Thinking otherwise is like thinking the universe expanded because of it was hot and the matter in it has a positive pressure, which is a common misunderstanding.

Not just mass sources gravity - energy does, and the pressure the energy or matter has is a contributing factor.

I'll probably leave the previous stuff about the big bang, it's too much of a derail here. Fork the thread if you wish.

That, I understand--a little. I read a bit on the search for Vulcan at one time, which I understand either incompletely, or most likely, wrong.
Now, the picture becomes clearer. It's still fuzzy, but I can tell there is something there, now.
Thanks.

 

[MattusMaximus]

Outside of social pressures, of course, which do have negative values.

Boo