Lambda-CDM theory - Woo or not?

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Michael Mozina said:
No, there is no area in the experiment that experiences ''negative pressure"! The whole thing can be done in virtually *any* positive pressure environment and we can't even make a "pure vacuum" with *no pressure", let alone "negative pressure".



Now your just confusing force with pressure. The "force" is actually coming from the *outside* of the plates. Anything inside the plates is due to molecular attraction. There is no "negative pressure" involved.



Hoy. No. We are left with *subatomic pressure* in the form of EM carrier fields. I botched my explanation to Derek by using the term "magnetic plates" when I meant "metallic plates", but the rest is valid. The whole reason that the type of material is relevant is because EM fields have unique effects on many metallic objects like steel. This tells us the carrier particles involved, but it has nothing whatsoever to do with "negative pressure".



Why do they report "magnetic reconnection"? Beats me. Pressure and force are not the same. I have have positive pressure in the chamber and "directional force" that pushes the plates together. That's all that is happening here.



I was only trying to use the idea as an *analogy* and all that did is create pure confusion. As I noted earlier on several occasions, the WIKI explanation is quite valid. Where does it say "negative pressure" exactly in that article by the way?

Those arrows are in fact "pressure". There is "more pressure" on the outside of the plates, and 'less pressure" between them, but even the subatomic process is based on "more kinetic energy on the outside and less of it on the inside". It's all positive kinetic pressure, even at the subatomic level. There is simply "more force" outside the places than inside the plates due to "positive kinetic pressure".
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Well you were almost starting to get it there with “directional force”. A force, as a vector, has direction. For any direction that we ascribe as positive the opposite direction would be negative and so would a force applied through that direction. You seem to be focusing on absolutes or negative values as only less then zero. In geometry negative also denotes direction and not simply a location to the left or right of some absolute zero point. It is in fact the vector additions of these + and - directions of force that demonstrate Newton’s third law (equal and opposite reaction), as well as the conservation of energy. As has been explained to you before the repulsive forces are generally considered positive or a positive vector (along a positive radial or planar direction) making attractive forces negative.
 
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Michael Mozina said:
The term "negative pressure" is a misleading idea, since all you are doing is "stressing' the bonds of the atoms in the liquid, much like you could also do with a solid.
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What in the world do you think the term "pressure" actually means? I've asked you this directly, because I think it's absolutely at the heart of your miscomprehension, but you didn't answer. I gave my definition. In fact, I gave two definitions that work. You have not said you agree with them, but you haven't objected to them either. Until we settle that, we will not get any further.

It's pure stress!
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So what? It still produces negative pressure, according to the definitions of pressure I gave you. If you want to propose your own definition of pressure, feel free to do so. Until then, I'm using my definition, and stress can produce pressure. No surprise there.

It's would be like putting solid gelatin in the container and doing the same thing.
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Well, yes. Except that solids can sustain non-symmetric stress as well (meaning different stresses in different directions), whereas liquids cannot. In mathematical terms, stress is a 3x3 symmetric tensor, which means 6 independent parameters, all of which can be different for a solid. But for a liquid (and a gas), the stress tensor is necessarily diagonal, with those diagonal elements equal to the pressure.

You could do that with virtually any solid too if you attached the piston to the solid.
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Not quite. The stresses would not be symmetric in that case, but uniaxial, so categorizing the resulting stress tensor with a single number would not make sense.

Come on. You're changing terms as go.
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Not at all. I have from the beginning used a very basic and very common definition of pressure. And everything I have said has been consistent with that definition. You, on the other hand, have never given any definition. Do you even have one? I cannot even tell if you've been consistent, because I still don't know what on earth you mean by the term.

First we were talking about negative pressure in a vacuum. Now you're trying to compare that to stress on bonds in a liquid. These are not the same concepts
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Sure they are, because the details of the mechanism are irrelevant for the definition I'm using, which (once again) is
[latex]$P=-\frac{\partial E}{\partial V}$[/latex]

These are two *entirely* different circumstances in the first place.
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In the sense that our function for E is different, yes. In the sense that the definition I gave for pressure still applies, no, it's exactly the same.

So once again: do you understand the definition of pressure I gave? Do you accept that definition of pressure? There is no point in proceeding further if we cannot even agree on what the term "pressure" means.
 
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Michael Mozina said:
Were you intending to use a Kelvin scale or some other scale?
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Oh, so you don't know about negative temperatures. Not that I'm surprised. But yes, negative temperatures on absolute temperature scales do exist. They are actually what you would conventionally think of as hot, they only occur in certain sorts of systems, and they are unstable configurations, but they are quite real. And yes, you can even make them in a lab.
 
temporalillusion said:
Lol awesome, consider my mind blown!
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It pretty simple, actually. If you want your definition of temperature to be consistent with the laws of thermodynamics, dE = T dS, where E is the energy and S the entropy. So 1/T = dS/dE. Therefore if we can find a system in which the entropy decreases as the energy increases, it will have negative temperature.

But that's easy: consider a system of N quantum 1/2 spins in a magnetic field. The ground state is all spins aligned with the field. The total number of states is 2^N, so the maximum entropy is N log 2, and that maximum entropy state consists of the spins aligned randomly (N/2 pointed up, N/2 pointed down). But that state is plainly not the maximum energy state (all spins anti-aligned with the field is). Therefore S(E) reaches a maximum somewhere between the ground state and the maximum - and so T goes to +infinity, wraps around to -infinity, and increases from there as you increase E :).
 
The Man said:
Well you were almost starting to get it there with “directional force”. A force, as a vector, has direction. For any direction that we ascribe as positive the opposite direction would be negative and so would a force applied through that direction. You seem to be focusing on absolutes or negative values as only less then zero. In geometry negative also denotes direction and not simply a location to the left or right of some absolute zero point. It is in fact the vector additions of these + and - directions of force that demonstrate Newton’s third law (equal and opposite reaction), as well as the conservation of energy. As has been explained to you before the repulsive forces are generally considered positive or a positive vector (along a positive radial or planar direction) making attractive forces negative.
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IMO, this seems to be the problem in a nutshell. Guth (and the mainstream) is confusing "pressure" with "force". Guth's theory specifically requires "negative pressure" from a "vacuum", not an "external force". These are horses of an entirely different color.
 
Michael Mozina said:
IMO, this seems to be the problem in a nutshell. Guth (and the mainstream) is confusing "pressure" with "force". Guth's theory specifically requires "negative pressure" from a "vacuum", not an "external force". These are horses of an entirely different color.
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Not at all, as has already been pointed out to you, pressure is just force over area; with a negative force you have negative pressure. Once again this is required by Newton’s third law and the conservation of energy. Without the negatives those laws just don’t add up.
 
Michael Mozina said:
IMO, this seems to be the problem in a nutshell. Guth (and the mainstream) is confusing "pressure" with "force".
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He's using exactly the same definition I've been giving to you:
[latex]$P=-\frac{\partial E}{\partial V}$[/latex]
Do you understand this definition of pressure? Do you accept it? Or do you want to use a different definition? If so, tell us what definition of pressure you want to work with. But without knowing what definition you are using (and given your denial that liquids can be at negative pressures, you're obviously not using that one), there's no chance for any common ground.
 
Ziggurat said:
What in the world do you think the term "pressure" actually means?
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Evidently it means something very different to you than what it means in ordinary physics and vacuums. You're confusing pressure and force. While it is entirely possible that there is some 'external force' pulling on the process (like your piston example), there is no such thing as a "negative pressure" in a "vacuum". These are entirely *different* ideas and concepts. I'm not even going to worry about the rest of your post until you recognize this distinction.

There is no "negative pressure" in a Casimir experiment, just "force" being applied to the plates from the quantum realm. There is no "negative pressure" involved, just "force". The idea that "force" can be looked at in a similar manner as "pressure", does not give Guth the right to interchange these terms. They are not one and the same concept. "Pressure" in a "vacuum" could theoretically reach a "zero", but it can never achieve "negative pressure". There certainly could be some "external force" tugging on the near singularity thingy he has going, but there is no such thing as "negative pressure" in a vacuum, and that is what Guth's theory specifically requires and needs in order to function. It's dead in the water because he confused "pressure" with "force'.
 
sol invictus said:
It pretty simple, actually. If you want your definition of temperature to be consistent with the laws of thermodynamics, dE = T dS, where E is the energy and S the entropy. So 1/T = dS/dE. Therefore if we can find a system in which the entropy decreases as the energy increases, it will have negative temperature.

But that's easy: consider a system of N quantum 1/2 spins in a magnetic field. The ground state is all spins aligned with the field. The total number of states is 2^N, so the maximum entropy is N log 2, and that maximum entropy state consists of the spins aligned randomly (N/2 pointed up, N/2 pointed down). But that state is plainly not the maximum energy state (all spins anti-aligned with the field is). Therefore S(E) reaches a maximum somewhere between the ground state and the maximum - and so T goes to +infinity, wraps around to -infinity, and increases from there as you increase E :).
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Thanks! Yeah the example I was reading had them on a 1 dimensional wire, but the same thing.
 
Ziggurat said:
He's using exactly the same definition I've been giving to you:
[latex]$P=-\frac{\partial E}{\partial V}$[/latex]
Do you understand this definition of pressure? Do you accept it? Or do you want to use a different definition? If so, tell us what definition of pressure you want to work with. But without knowing what definition you are using (and given your denial that liquids can be at negative pressures, you're obviously not using that one), there's no chance for any common ground.
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It is not even reasonable for you to be comparing a "liquid" to a "vacuum". Guth specifically states that there is "negative pressure" in a "vacuum". He did not state anything about a liquid. This is ultimately a red herring unrelated to his claim, and another excellent example of your confusion between "force" and 'pressure'.
 
Michael Mozina said:
Mathematics can indeed correctly describe the physical processes of nature, but physics is a physical process that can often be very difficult if not impossible to correctly mathematically model.
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Impossible for you because you can't do math. :)
 
GeeMack said:
Impossible for you because you can't do math. :)
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No, this is another really excellent example of the idea that your side cannot distinguish between a math formula and physical reality. In physical reality a "vacuum" can achieve a zero energy state, at least in theory. It could *never* achieve a 'negative pressure' because such a concept is physically impossible. It's a mathematical mythos that Guth created because he didn't pay attention to the realm of actual "physics". There's no point in comparing "liquids", to "vacuums", but of course you'd love to simply ignore the *physical differences* between the two environments. You folks may be able to do math, but your understanding of physics is severely lacking. In the language of "physics", liquids != vacuums, and "pressure != force".
 
Michael Mozina said:
It is not even reasonable for you to be comparing a "liquid" to a "vacuum".
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Once again, you are ignoring the question of the definition of pressure. Do you or do you not accept the definition of pressure I gave? If so, then we can apply it to liquids, we can apply it to gasses, and we can apply it to vacuums, and see what we get each time. But until you either accept the definition I gave you or suggest your own, there's not going to be any progress.

Is your hesitation to respond because you don't understand what that equation means? I actually hope you can, but you're so unfamiliar with so many things in physics, and you've yet to show that you can do any math at all, so at this point I'm actually not optimistic.
 
Ziggurat said:
He's using exactly the same definition I've been giving to you:
[latex]$P=-\frac{\partial E}{\partial V}$[/latex]
Do you understand this definition of pressure? Do you accept it? Or do you want to use a different definition? If so, tell us what definition of pressure you want to work with.
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Ok, let's say we try....

[latex]$P=-\frac{\partial (MC^2)}{\partial V}$[/latex]
 
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Michael Mozina said:
No, this is another really excellent example of the idea that your side cannot distinguish between a math formula and physical reality. In physical reality a "vacuum" can achieve a zero energy state, at least in theory. It could *never* achieve a 'negative pressure' because such a concept is physically impossible. It's a mathematical mythos that Guth created because he didn't pay attention to the realm of actual "physics". There's no point in comparing "liquids", to "vacuums", but of course you'd love to simply ignore the *physical differences* between the two environments. You folks may be able to do math, but your understanding of physics is severely lacking. In the language of "physics", liquids != vacuums, and "pressure != force".
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Cannot distinguish? That is kind of the whole point, to model physical events so accurately that the mathematical results are ‘indistinguishable’ from the observed results. Just what do you think physics is anyway? Now feeling the sun on your face, a nine volt battery on your tongue or whatever you can find at Wall-mart may be what you consider physics but that is not going to get you very far at the Large Hadron Collider. Even if you do want to volunteer to stick your face in the detector array with your tongue sticking out and whatever you found at Wall-mart to see what you can detect in the collision? Most of us however, would prefer to just stick with the installed detectors and the applicable mathematics.
 
The Man said:
Cannot distinguish?
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Nope. The Lambda proponents do not seem to respect or acknowledge the physical differences between "pressure" and "force", nor will they distinguish between liquids and vacuums. That's a serious problem at the level of physics.

That is kind of the whole point, to model physical events so accurately that the mathematical results are ‘indistinguishable’ from the observed results. Just what do you think physics is anyway?
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As long as you're doing that with known and physically possible entities, I have no problem with that idea. When these mathematical models are based upon physical impossibilities and "ad hoc" forces of nature, then it's an entirely different issue.

Now feeling the sun on your face, a nine volt battery on your tongue or whatever you can find at Wall-mart may be what you consider physics but that is not going to get you very far at the Large Hadron Collider.
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While the LHC is a perfect exactly of a real "science experiment" that has some hope of finding a Higgs, no hardware on Earth could ever be useful in finding a now nonexistent entity. I can appreciate the value of LHC as it relates to particle physics theory, but no such hardware could ever be useful in verifying inflation.

Even if you do want to volunteer to stick your face in the detector array with your tongue sticking out and whatever you found at Wall-mart to see what you can detect in the collision? Most of us however, would prefer to just stick with the installed detectors and the applicable mathematics.
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Well, me too. :) Then again, this is a perfect example of "empirical physics" and "empirical experimentation". LHC is "by the book" physics. If you had such a "controlled experiment" underway to find and verify inflation, I wouldn't be squealing like a pig. Since that is a physical impossibility, what else is left but a giant leap of faith? Why should I hold belief in a dead and useless entity that was originally postdicted and predicated upon a physical impossibility, specifically a "negative pressure vacuum"?
 
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Michael Mozina said:
Ok, let's say we try....

[latex]$P=-\frac{\partial (MC^2)}{\partial V}$[/latex]
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Let's not. Among other things, it's a poor way to try to calculate the pressure inside a black body cavity due to radiation, since photons are massless. Relativistic mass is an outdated and superfluous concept, one that pretty much no practicing physicist still uses. I'm in that group.

But do you even understand the equation I gave for pressure, or did you just try sticking in the one physics equation you ever wrote down into what I gave you?
 
Michael Mozina said:
Translation: No Michael, don't convert energy to mass because then my confusion between pressure and force becomes damn obvious!
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:rolleyes:

E=mc2 works fine for masses at rest. If you want to apply it to masses in motion, then this equation is in effect defining what you mean by mass, namely what is termed "relativistic mass". But there's simply no need to ever do so. You can relate mass and energy perfectly well using invariant mass, using
E2=m2c4+p2c2Now, you could in principle substitute this equation (or, more specifically, the square root of this equation) into my definition of pressure, but since calculating the various components for all the constituent elements of the system is frequently much more difficult than calculating an overall energy function in terms of your macroscopic parameters, there's no bloody point. Which is why I said "let's not". Deriving the idea gas law from that equation would be a serious pain, because the calculations would become far more complex than they need to be if you just consider energy directly. Which is why nobody does that. But you can find a derivation of the ideal gas law directly from [latex]$P=-\partial E/\partial V$[/latex] rather easily in basically any thermodynamics textbook.

Besides which, it's an absurdity to think that my definition confuses pressure and force, or that the version you wanted clarifies that in any way. Just look at the units.
 
Enjoying your "conversation" with MM, Zig? :)

How could anyone but a complete ignoramus think pressure and force are in danger of being confused with one another? For one thing, they have different units. For another, pressure is a scalar (under rotations); force is a vector.
 
sol invictus said:
Enjoying your "conversation" with MM, Zig? :)
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"Enjoy" isn't quite the right word either. But it is interesting to find out how deep his confusion goes. Somewhere in his head, he's got some model about what pressure is, and I'm curious about what exactly that model is, because it's clearly leading him to make some serious errors.

I'm reminded a bit about a question I saw posed to MIT engineering students as they graduate. They were shown an apple seed, then a log from a tree that once grew from such a seed. Obviously over the course of its life, the tree gained considerable mass. They were asked where most of that mass came from. Most said from the soil or from water. Almost none of them answered correctly that it came from the air. It's not that they're stupid, it's that they've got some internal working model about how trees grow, and they were never challenged in their education in a way which actually exposed that model to examination.

MM's got some similar errors going on, but two things distinguish it: first, that his mistakes are so bad for someone supposedly interested in the subject, and second, that he is so resistant to having his internal models examined, challenged, or modified in any way.

You were spot on with the negative temperatures bit, though.
 
Michael Mozina said:
Nope. The Lambda proponents do not seem to respect or acknowledge the physical differences between "pressure" and "force", nor will they distinguish between liquids and vacuums. That's a serious problem at the level of physics.



As long as you're doing that with known and physically possible entities, I have no problem with that idea. When these mathematical models are based upon physical impossibilities and "ad hoc" forces of nature, then it's an entirely different issue.



While the LHC is a perfect exactly of a real "science experiment" that has some hope of finding a Higgs, no hardware on Earth could ever be useful in finding a now nonexistent entity. I can appreciate the value of LHC as it relates to particle physics theory, but no such hardware could ever be useful in verifying inflation.


Well, me too. :) Then again, this is a perfect example of "empirical physics" and "empirical experimentation". LHC is "by the book" physics. If you had such a "controlled experiment" underway to find and verify inflation, I wouldn't be squealing like a pig. Since that is a physical impossibility, what else is left but a giant leap of faith? Why should I hold belief in a dead and useless entity that was originally postdicted and predicated upon a physical impossibility, specifically a "negative pressure vacuum"?
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No one but you seems to have a problem distinguishing “pressure” and “force”. Just how do you determine what are “physically possible entities”? Now you say “the LHC is a perfect exactly of a real "science experiment" that has some hope of finding a Higgs” but that is precisely one of those “physically possible entities” projected by current models and not currently detected. It is also the same model that projects inflation resulting from a phase transition of the Higgs field and the results of the inflation have been detected. So on the one hand you call it “”by the book” physics” but then find yourself “squealing like a pig” because you want to decide what “is a physical impossibility” without considering the actual models permitting your “by the book” “physically possible entities” like the Higgs boson? The Higgs boson and inflation are from the same “”by the book” physics” (or current model), quite literally on the same page as well and that ‘book’ like all physics takes a lot of math to read and understand correctly.
 
Michael Mozina said:
You've all failed to demonstrate any sort of "negative pressure" in a vacuum. The failure has been yours, and indeed it's been a failure of epic proportions because Guth's theory is dead in the water unless you can demonstrate such a thing is possible.
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We have, the Casimir effect.


Mathematics can indeed correctly describe the physical processes of nature, but physics is a physical process that can often be very difficult if not impossible to correctly mathematically model.
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But not the Casimir effect since the experimental results agree witht he theoretical predictions.

Er, you must have missed the key quote I pulled from the body of the paper about negative pressure in a vacuum? I haven't even really focused on the rest of the problems in this paper (which was actually "falsified" (if you can call it that) by the way). I'm simply noting that he has a *key* problem in his understanding of a vacuum and physics of a vacuum. There can be no such thing as "negative pressure" in a vacuum.
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The problem is entirely at your end.

BS. I can turn on my plasma ball and watch it function and know absolutely nothing about the 'math' that might be useful in describing the motion of those filaments in the plasma. You can do "physics" in a physical way too without having any preconceived understanding of the math.
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We're talking precision measurement here. Not just some hand wave qualitative agreement (which, by the way, you don't even have).


The primary problem with Guth's claims are not related to his "math". You folks keep insisting that only mathematics matters, but the physics also matters. Vacuums do not contain "negative pressure". They can't. That's the problem in Guth's theory. He stuck a minus sign in from on pressure. Mathematically it works. Physically it does not.
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Negative pressure does exists. As evidenced by the Casimir effect.

No, all you have are math formulas applied to words that make no physical sense. There is no such thing as a 'negative pressure' in a vacuum.
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There can be. Its a result of quantum mechanics.

The best we can ever achieve is a "low pressure". Not every flaw in every theory is related to math. When are you going to accept that reality?
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When are you going to admit that you have no idea what you're talking about.

That is not true. First of all this was *not* a vacuum. It was a "liquid" with "bonding" processes in the liquid. You could have done the same thing with a solid and stressed it's bonds until it broke in a similar manner, but that is not 'negative pressure', that is "stress", put on "bonds" in the liquid.
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What on Earth are you talking about?

It's irrational to even be comparing a vacuum to a solid or a liquid. It would be rational to compare it to a gas or a plasma, but Guth expressly applied this idea to a "vacuum", not a "liquid".
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Your paragraphs no longer make even the slightest hint of sense. Guth expressly compared his vacuum to "a "vacuum", not a "liquid"". What?
 
No, this is another really excellent example of the idea that your side cannot distinguish between a math formula and physical reality. In physical reality a "vacuum" can achieve a zero energy state, at least in theory.
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No.
 
Michael Mozina said:
Why do the papers report an negative force and so pressure when such a pressure cannot exist?
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Why do they report "magnetic reconnection"? Beats me. Pressure and force are not the same. I have have positive pressure in the chamber and "directional force" that pushes the plates together. That's all that is happening here.
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They keep reporting magnetic reconnection because that is what they measure.
They keep reporting the Casimir effect as an attractive force producing a net negative pressure because that is what they measure.

You keep forgetting that this is the net force and so the net presssure that is measured after taking account of the "positive pressure" in the chamber.

FYI: The relationship between force and pressure is that pressure is the force per unit area in the device. The area of the plates (or plate and sphere) are known. Thus the pressure is calculated by dividing the force by the area.

Or are we back to you claiming that experimental physicists are so dumb that they do not know that there are atoms in their vacuum chamber and their effect needs to be accounted for?
 
Michael Mozina said:
I can turn on my plasma ball and watch it function and know absolutely nothing about the 'math' that might be useful in describing the motion of those filaments in the plasma.
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This might be one of the most accurate things you've said here so far.
 
DeiRenDopa said:
[...]
Skwinty said:
The reason I ask is:

The expansion of space, which is the predominant interpretation of cosmological redshift, is the foundation of the BBT, specifically when running time in reverse.

Or, am I misunderstanding the issue?
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You are, in one respect.

The CMB, the primordial abundance of light nuclides, and large-scale structure are just as much "foundation of the BBT" as the Hubble relationship. And, as si has noted, the one thing which ties this all together is GR.

The true theoretical underpinning of the BBT is GR.

And that is the reason why, when all is said and done, that what "many are trying to prove" is nothing other than a falsification of GR (or a dramatic revision of it).

[...]
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(bold added)

Upon reflection, I think this is only partly right ...

In terms of volume of data, the overwhelming source of observations used to test cosmological models/concepts/etc is the detection of photons (or, if you prefer, electromagnetic radiation).

The detections ('observations') are analysed within a framework that includes two vital assumptions: some form of a Copernican principle (crudely, we are not in a special place in the universe), and that photons are photons are photons. The two are not independent, but are also not identical (I think).

We may consider the latter to be something like the universality of QED, and there are certainly lots and lots and lots of tests done (and, no doubt many more that could be done) that show the wide ranging and deep consistency associated with an assumption of universality of QED ... but in some sense this is no different than saying that the true theoretical underpinning of the BBT is GR.

One implication that I got to thinking: to what extent are contemporary cosmological models (concepts, ideas) bolstered by observations other than those which are detection of photons?

At first, I couldn't think of any, but then I came up with quite a few; here's an interim list (in shorthand):

* Olbers' paradox in neutrinos (the Sun is the only observed extraterrestrial source of neutrinos - within selected energy bands and neutrino types/flavours - therefore ...)

* the cosmic ray energy spectrum and composition (this not only corroborates much of the photon-detection based observations, but also very likely sets some interesting, and possibly quite strong, constraints on QED beyond the solar system)

* the UHECR anisotropies (so far only the first Auger results, and so still rather tentative, but potentially very powerful)

* the elemental and isotopic composition of interstellar dust grains (may not say much about cosmology, but does provide independent support for some aspects of photon-based observations)

* something about the (so far) null detections from various gravitational wave radiation detectors (I'm not sure what these would mean if you set aside all photon-based observations as potentially subject to massive, subtle, etc systematics).

Maybe I should start a new thread on this ...
 
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edd said:
I think this is unfair. By the same argument you would surely have photons having invariant (well, zero) momentum, but they do not. Your argument is flawed in defining momentum as the product of mass and velocity.

I agree that it's pointless to draw some kind of distinction between the overall energy of a photon and kinetic energy and that kinetic energy is poorly defined, if at all, for a photon, from what I can see, but I think your approach to this is wrong.
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Not a problem for me, I am wrong more often than not. My point was that (excluding relatavistic mass) that it would be hard to say that EM radiation is kinetic energy.

IT is no suprise and wonder that I goobered it up. I feel that MM is using simple classic physics to explain how EM radiation is 'kinetic' and so my attempt is flawed (my thoughts). My thoughts are almost always likely to be wrong.

Does the 'kinetic' energy of a photon increase with the frequency? Will blue photons impart more push to a light sail? ( I am sure this is a poor use of terminology.)
 
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The Man said:
Well you were almost starting to get it there with “directional force”. A force, as a vector, has direction. For any direction that we ascribe as positive the opposite direction would be negative and so would a force applied through that direction. You seem to be focusing on absolutes or negative values as only less then zero. In geometry negative also denotes direction and not simply a location to the left or right of some absolute zero point. It is in fact the vector additions of these + and - directions of force that demonstrate Newton’s third law (equal and opposite reaction), as well as the conservation of energy. As has been explained to you before the repulsive forces are generally considered positive or a positive vector (along a positive radial or planar direction) making attractive forces negative.
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Thanks, that makes sense of something I have been trying to figure out for a long time.
 
Michael Mozina said:
IMO, this seems to be the problem in a nutshell. Guth (and the mainstream) is confusing "pressure" with "force". Guth's theory specifically requires "negative pressure" from a "vacuum", not an "external force". These are horses of an entirely different color.
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It is all about semantics after all.

Pkay then MM, why does the decrease in pressure decrease the temperatures in a compressed gas released from a pressurized state?

It is a negative temperature change just as it is a negative pressure change.
 
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Ziggurat said:
[...]

Well, yes. Except that solids can sustain non-symmetric stress as well (meaning different stresses in different directions), whereas liquids cannot. In mathematical terms, stress is a 3x3 symmetric tensor, which means 6 independent parameters, all of which can be different for a solid. But for a liquid (and a gas), the stress tensor is necessarily diagonal, with those diagonal elements equal to the pressure.

[...]
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(bold added)

Going a fair bit OT perhaps, but this may be interesting ...

Suppose you have a colloid in which a (ferro-)magnetic solid is suspended in a non-polar liquid. Suppose there is a uniform external magnetic field applied. Would the colloid be able to sustain non-symmetric stress? Or is this somehow ruled out in the definition (of a liquid)?

More generally, if placed in a sufficiently strong external magnetic field, would any liquid be able to sustain non-symmetric stress?
 
DeiRenDopa said:
Suppose you have a colloid in which a (ferro-)magnetic solid is suspended in a non-polar liquid. Suppose there is a uniform external magnetic field applied. Would the colloid be able to sustain non-symmetric stress? Or is this somehow ruled out in the definition (of a liquid)?

More generally, if placed in a sufficiently strong external magnetic field, would any liquid be able to sustain non-symmetric stress?
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Hmm... you know, I'm not sure. I don't think it would be forbidden, because you would be breaking a local symmetry (which is required, and which normally exists), but I'm not sure whether or not it would actually create non-symmetric stresses. It could also just create non-symmetric viscosities, so maybe in the relaxed state you'd still get symmetric stresses. Don't know, though.

As for being off topic, well, it's more interesting than anything MM has said.
 
Ziggurat said:
Hmm... you know, I'm not sure. I don't think it would be forbidden, because you would be breaking a local symmetry (which is required, and which normally exists), but I'm not sure whether or not it would actually create non-symmetric stresses. It could also just create non-symmetric viscosities, so maybe in the relaxed state you'd still get symmetric stresses. Don't know, though.

As for being off topic, well, it's more interesting than anything MM has said.
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Thanks.

Presumably it applies generally; for example a colloid composed of a ferromagnetic liquid and a gas (not sure if there is such a thing as a ferromagnetic liquid), or a colloid composed of two immiscible liquids of very different magnetic properties.

And what about (stress, pressure) behaviour of a liquid in a (strong, (but not too strong!), external) electric field (assume a neutral, non-conducting liquid)?

Within the scope of this OT mini-thread, are superfluids special in any qualitative way?

And do BECs (Bose-Einstein condensates) behave like (ordinary) fluids (i.e. diagonal stress tensor)?
 
Michael Mozina said:
DeiRenDopa said:
IOW, whatever "it" is, it is known to only one person; namely, MM ... or, perhaps, MM knows of only one person who knows this it (MM himself).
Click to expand...
Are you trying to suggest that mainstream beliefs are all consistent and invariable and consistent from individual to individual? Look and you and topic of inflation! Talk about the pot calling the kettle black.....

Look at "dark energy". It got stuffed into the theory only relatively recently.
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(bold added)

And earlier (extracts, bold added):
Michael Mozina said:
I have no idea who else might label themselves as someone who believes in EU/PC theory, whether they see some distinction between the two as you seem to do, etc. I simply define EU/PC theory as the combination of MHD theory and GR, and I have no idea how others define that label.
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And this extracted set of exchanges (bold added):

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
MM: Let me now ask you a point black question. Are you an advocate of inflation? Yes or no?

DRD: No.

MM: So why are you personally on that side of the aisle again?
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

I think it's accurate to say that for MM a serious component of cosmology has to do with (personal) beliefs, in a manner similar to religious or political beliefs.

For example, it seems, in the MM view, that everyone who has studied this general topic cannot be agnostic as it were, they must take a stance one way or the other. Further, in speaking (well, writing posts) on the subject it is almost impossible to avoid making one's stance public, and so be advocating one belief or another. (Of course my summary may be inaccurate, and, for example, omit some very important factors).

Have other readers of this thread reached similar conclusions?

To me, this illustrates another fundamental difference between MM's approach to cosmology, as a science, and that of most scientists; namely, a reversal of the relative importance of the idea (theory, model, whatever) and the process. I'm still wrestling with how to express this, but it seems to me that, to MM, the idea ("EU/PC theory" for example) is primary, and the processes and tools of cosmology (as a science) must be bent (or deployed) almost exclusively to proving the idea (or disproving any alternative); for most scientists it's the other way round - the scientific methods (tools, processes, approaches, etc) are primary and the ideas will come and go according to how extensive, consistent, etc their explanatory and predictive powers are.

So, for example, it is quite possible - even easy - for a scientist to write a paper presenting an observation-based case for one theory today, and a paper presenting an observation-based case for an entirely different, conflicting, theory tomorrow. I suspect that for MM this is almost incomprehensible, and that such a person would, almost by definition, be schizophrenic.

Have other readers of this thread reached similar conclusions?

Another thing: accessibility to "theories". In contemporary cosmology (and astrophysics, etc), it is usually very easy to determine the details of any theory - simply find the published paper(s) in which a theory is presented*.

Contrast this with "EU/PC theory", and leave aside (for now) the multiple inconsistencies in MM's various descriptions of what it is. What paper(s) would you read to understand this? Well, MM has sorta alluded to Birkeland's works ... but then from the definition of "EU/PC theory" ("the combination of MHD theory and GR") it follows that Birkeland's works cannot be "EU/PC theory" (neither MHD nor GR were invented then).

In this respect, MM's approach (or practice) is also very different than that used in contemporary science.

Have other readers of this thread reached similar conclusions?

* there may well be, of course, certain practical problems with this; not all journals are easily accessible, and sometimes the foundations of a theory require extensive further reading to understand (for example)
 
Reality Check said:
They keep reporting magnetic reconnection because that is what they measure.
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No. They keep "measuring' heat and particle acceleration. "Magnetic reconnection" is an "interpretation" of that observation. You guys really need to learn to distinguish between "observation" and "interpretation".

They keep reporting the Casimir effect as an attractive force producing a net negative pressure because that is what they measure.
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This is again a "false" statement. They measure "force" due to the casimir effect in a *positive pressure* environment. Again, it is *extremely* clear to me now that you folks are confusing *pressure* and *force*. The Casmir effect is a great example of this. The whole environment is *positively pressurized*, so there is no physical way that any location in the chamber experiences "negative pressure", just force.

The same would be true if we put two magnets together in a positive pressure environment. Yes the north and south ends of two magnets will experience *attraction*, but the space in between the two magnets never experiences "negative pressure".

FYI, it's going to be a busy day at work for me today.
 
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Dancing David said:
It is all about semantics after all.
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No, it's about *physics* after all.

Pkay then MM, why does the decrease in pressure decrease the temperatures in a compressed gas released from a pressurized state?
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What does that have to do with the price to tea in China? I didn't pick on that idea in Guth's paper, I took exception to his claim about "negative pressure" in a 'vacuum'.

It is a negative temperature change just as it is a negative pressure change.
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It is indeed a temperature changes from one *greater than zero (Kelvin)* temperature to a lower temperature that is also greater than zero.

There seems to be two fallacies in play here. First pressure and force are not the same idea, and secondly, a fall in something (temp, pressure, etc.) does not necessarily equate to a "negative" state, just a "less positive" one.

The picking of an arbitrary zero point seems to be related to the second fallacy in play, but the big mistake Guth made and your side is still making is equating pressure and force as one and the same idea. They are not. There is "force" in the Casimir effect that pushes the plates together, but there is no "negative pressure" in a positive pressure chamber.
 
DeiRenDopa said:
I think it's accurate to say that for MM a serious component of cosmology has to do with (personal) beliefs, in a manner similar to religious or political beliefs.
Click to expand...

Er, no. I simply note the difference between a "faith based" religion and empirical science. Inflation is a "faith based" belief system.

For example, it seems, in the MM view, that everyone who has studied this general topic cannot be agnostic as it were, they must take a stance one way or the other.
Click to expand...

If you weren't over there at BAUT holding regular witch trials, insisting on *not* discussing EU ideas, and insisting that only your *religion* has merit, then maybe your statements would not ring nearly as hollow as they do. Since you folks go out of your way to burn all your heretics at the stake and virtually execute the most vocal critics, your feign of agnosticism" is utterly absurd. You're a "believer" to the point of participating in (in your case overseeing) the virtual execution of all dissent. The Lambda-religion is not full of agnostics, it's full of hard core followers that attack any and all dissenters, and who refuse to allow other belief systems to even be discussed openly and fairly. Every competing theory has to be judged based on your own preferred standards and observations. Even though you personally don't believe in inflation, somehow any competing theory has to be "just as good" as your theories in ways that you personally decide, "or else". You impose 30 days time limits on all topic *except your own religion*.

Make no mistake about it, Lambda theory is a "religion". It's core tenets are based on "faith", not on empirical science. It's followers do not allow for, nor condone dissent. If you get out of line, you get virtually executed on the internet, and we can only assume it's worse in person when your job and livelihood are on the line .
 
DeiRenDopa said:
We may consider the latter to be something like the universality of QED, and there are certainly lots and lots and lots of tests done (and, no doubt many more that could be done) that show the wide ranging and deep consistency associated with an assumption of universality of QED ... but in some sense this is no different than saying that the true theoretical underpinning of the BBT is GR.
Click to expand...

And this would be another great example of "false advertising". GR theory is a theory about the *attractive* curvature of gravity. BBT is dependent upon inflation and dark energy, neither of which are technically even related to GR, they are just stuffed into a GR formula. If there was truth in advertising, you wouldn't be able to get away with claiming that the underpinning of BBT is GR. It's not.
 
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