Lambda-CDM theory - Woo or not?

[DeiRenDopa]

In his (first) response to TimT's "Comments on Birkeland & Electricity & the Sun" post (#1651 in this thread), MM said (bold added):

TT: "So while it is fair to say that Birkeland did think that there was a flow of material from the sun to the earth, it is clear that his conception of the flow is both qualitatively & quantitatively different from what we now call the "solar wind"."

MM: "Er, no. It was "quantitatively different" to be sure, but the "qualitative" part is still right on the money. We know from his experiments that the key observations we're seeking to explain in solar phenomenon are in fact relate to electrical discharges. The numbers have changed to be sure, but the basic idea is sound and it works in a lab. You're confusing the notion of "quantitative differences" for "qualitative failure". There is no one to one correlation between these two ideas. Quantitatively things are different than he imagined, and even some of the physical parameters are a bit different, but the basic concept works in the lab. "

So what, to MM, is this "basic idea" that is sound, even if it is ""quantitatively different""?

The "works in a lab" part is, of course, true ... by definition (as can be verified by repeating Birkeland's experiments).

Here's what MM says it is (refer to the 994-page Birkeland material for a full description)(post#1534):

[Birkeland] charged the sphere [representing the Sun] as a cathode relative to the chamber walls

But what is the basic idea that is sound when it comes to the solar wind?

MM states it several times in this thread, in somewhat different ways*, but these are particularly clear:

(source) "Solar wind acceleration is not a "mystery". It was "explained' and 'simulated' in a lab, over 100 years ago. It is 'caused' by charge separation between the photosphere and heliosphere. [...] This was all demonstrated in a lab over 100 years ago."

(source) "We're sitting inside of a "current flow' between the surface of the sun and the heliosphere."

(MM's first response to TT's post, cited above) "[Birkeland] suggested [the Sun] was "discharging" itself toward the heliosphere."

One point to immediately clarify is what is the "heliosphere" MM is referring to.

It's not a term that Birkeland uses**.

And the normal meaning of the word, today, is that it's what the solar system is in ... i.e. a bubble that is centred on the Sun and extends to where the solar wind begins interacting with the ISM (inter-stellar medium) at the heliopause or heliosheath (to distinguish it from the regions immediately around planets - especially the Earth and Jupiter - it has the same meaning as the inter-planetary medium). As such what MM says makes no sense ... so perhaps he means the heliopause? or the heliosheath?

So the basic idea that is (qualitatively) sound is that the solar wind is a kind of discharge process (according to MM).

If so, then we have a proposed mechanism, a process, that can be used to formulate testable hypotheses, which we can then proceed to test. And we can do this quite independently of whatever experiments Birkeland conducted in his lab.

OK so far? Any clarifications needed? Did I misunderstand what you wrote MM (in any significant way)?

(to be continued)

* for example in posts 134, 367, 600, and 645.
** or if it is, I couldn't find it; inputs welcome!

 

[Michael Mozina]

The plates need not move at all. The pressure is there whether the plates move or are held in place.

There is "pressure" (iow air pressure) on both sides of the plates, and there is another QM "force" that is related to the EM field that is "pushing" on both sides of the plates! How can you *still* believe that there is "negative pressure" involved when both the air in the chamber and the photons that carry the EM field *push* against *both* sides of both plates? There is no "negative pressure" in a vacuum, just "positive pressure" pushing on both sides of the plates, and positive force pushing on both sides of the plates?

I get the distinct impression by the way that this issue relates directly back to Guth's "reheating problem". If the vacuum actually had "negative pressure" and stayed that way throughout the process, it would have never stopped, the "bubbles" (of unknown substance) would not "push" against each other, and nothing would "reheat".

Perhaps you should answer the simpler situation which ignores all of the Casimir stuff.

The Casimir stuff is what you tried to use to justify your claim about "negative pressure in a vacuum". There is no such thing going on. There is "pressure" (air pressure) that pushes on both sides of the plates, and "force" related to QM that pushes on *both* sides of the plates!

How can anyone here still be defending the idea that a vacuum can have negative pressure? It's physically *impossible* for that to happen.

 

[Ziggurat]

Gah! How can you *still* believe in negative pressure in a vacuum?

How can you still be unable to define pressure? Some mysteries are deep.

Actually, in the case of the Casimir article, the WIKI presentation was correct. Only your crew seems to be incapable of distinguishing between a QM "force" and pressure

Everyone but you understands the difference as well as the connection between force and pressure.

 

[Michael Mozina]

If I may, these need some editing, in order for them to be reasonably free of ambiguity and also phased more appropriately for this section of the JREF Forum.

A) Are there experimental results consistent with "negative pressure in a vacuum"?

The answer is no! The Casimir effect has *nothing* whatsoever to do with "negative pressure in a vacuum". There is a Casimir QM "force" that is related to the EM field, that pushes on *both* sides of the plates!

B) Are there observations and experimental results consistent with "the observable universe has a net energy of zero"?

No.

The answer to both questions would be yes, IMHO.

Start with the first one then. What experimental results suggest that a vacuum can contain negative pressure? Be specific.

 

[edd]

How can anyone here still be defending the idea that a vacuum can have negative pressure? It's physically *impossible* for that to happen.

I don't suppose it helps, but it's really got nothing to do with what particles hit what side of the plate and what force individual particles exert*. It is about how the energy within a volume changes. That's the solely relevant aspect of the discussion.

Can you give an argument why when volume decreases it is physically impossible for the contained energy density to decrease also?

*well, by nothing I mean that it's not the directly relevant aspect of the physics. Obviously there can be physics linking that to the energy in a volume.

 

[DeiRenDopa]

I have completed a re-reading of the relevant parts of this thread.

I can find no post by MM that addresses this.

How many of my personal questions have you completely ignored now?

Dunno.

Would you like to go through this whole thread, note the posts in which you asked them, and write up the results?

I'll be happy to take a shot at answering such questions.

You won't tell us what caused the whole thing to go "bang" one fine day, but you do reject inflation. You won't tell us what the size might have been prior to the "bang". You can't tell us what "form" the energy might have been in prior to the bang. You can't tells us what "dark energy" actually is, nor is there any particular reason to rename "acceleration" in the first place. So in terms of real "physics" what do you personally have to offer me DRD?

Personally? None whatsoever.

DRD is not the author of any published paper, much less one on physics.

Nor is DRD the author of any textbook on physics.

And so on.

What I can try to do is explain what I understand contemporary cosmology, astrophysics and (parts of) physics are ... to you and any other reader*.

You seem to distance yourself from even the mainstream theory as it relates to inflation, so you sound positively hypocritical from my perspective. You get to pick and chose what things you believe in, but I don't have that same luxury?

Ah that "belief" thing again.

One rather fundamental difference between your apparent concept of science and mine is the role each of us considers "belief" to play in science; would it be worth exploring this perhaps?

Back to unanswered questions.

Over at the space.com forum, it seems that many folk there were very unhappy with your behaviour of not answering questions (see the link I gave earlier, and follow that thread to pages 3 and 4).

It seems your track record in this thread is (qualitatively) the same; in the post of mine you are quoting I gave five such questions, and since then you have had a go at answering just one.

What say you, other readers; should someone (me?) compile a list of unanswered questions?

I for one will certainly be repeating mine on "known forces of nature" (but I have zero expectations re mine on where in the B tome "jets" are covered).

* and, FWIW, there is objective, independently verifiable evidence that I have had some success at this - in the form of posts by other JREF Forum members.

 

[DeiRenDopa]

If I may, these need some editing, in order for them to be reasonably free of ambiguity and also phased more appropriately for this section of the JREF Forum.

A) Are there experimental results consistent with "negative pressure in a vacuum"?

The answer is no! The Casimir effect has *nothing* whatsoever to do with "negative pressure in a vacuum". There is a Casimir QM "force" that is related to the EM field, that pushes on *both* sides of the plates!

[qimg]http://upload.wikimedia.org/wikipedia/commons/thumb/4/44/Casimir_plates.svg/300px-Casimir_plates.svg.png[/qimg]

B) Are there observations and experimental results consistent with "the observable universe has a net energy of zero"?

No.

The answer to both questions would be yes, IMHO.

Start with the first one then. What experimental results suggest that a vacuum can contain negative pressure? Be specific.

Not so fast!

You omitted the rest of my post; here it is again (in bold):

If I may, these need some editing, in order for them to be reasonably free of ambiguity and also phased more appropriately for this section of the JREF Forum.

A) Are there experimental results consistent with "negative pressure in a vacuum"?

B) Are there observations and experimental results consistent with "the observable universe has a net energy of zero"?

The answer to both questions would be yes, IMHO.

It is important to note several features of my edited version:

1) the statements are objectively, and independently, verifiable (it matters not one jot what MM, DRD, si, ... believes, supports, thinks, feels, ...)

2) the parts in quotation marks are only unambiguous wrt standard, contemporary, textbook definitions of the key terms "pressure", "vacuum", and "energy" (change the definition of any term and the statements will be different, and - very likely - ambiguous)

3) both statements assume full acceptance of the aspects of theories in modern physics consistent with every facet of every relevant observation and experiment (so, for example, take QED off the table and every modern experiment and astronomical observation needs to be re-analysed).

The last one (3) is a biggie, and probably has wide ramifications for much of what you have posted in this thread MM.

(there's also an error in your transcription; "Are there experimental results consistent with" is what I said; do you understand the difference, cf what you wrote?)

Here's what I'll do: this thread already contains many posts on this topic, including direct answers provided by others. More importantly, this thread also contains definitions of the key terms ("negative pressure" and "vacuum" in this case), definitions that are just what my point 2) is about. I'll go dig up the relevant posts, and copy them That way you'll see exactly how you missed the key things at least once before.

 

[Michael Mozina]

I'm not sure anyone answered this, so I'll take a crack at it.

When people say there was no matter in the early universe, what they mean is that the energies were so high that no matter in any ordinary form could exist.

If the energies were "high" then we start with a "net positive" energy state, no?

There was lots of radiation, and lots of very fast moving elementary particles (which you might want to call "matter" - it's a matter of taste ). If you were to stick a chunk of, say, iron in there, it would vaporize almost instantaneously into a cloud of very energetic photons, quarks, electrons, gluons, etc.

Are there any Higgs particles that might generate a gravitational field and cause the whole thing to "implode" for instance?

That might make it difficult to measure the temperature with a thermometer, but there's no difficulty in defining it. Recall that temperature in a gas is a measure of the average kinetic energy of the molecules. In a very hot state like the early universe, the same definition applies - high temperature means high average kinetic energy for the particles (and high frequency for massless particles like photons and gluons).

How big was this "thingy" when actual mass particles existed? The moment you have Higgs particles and theoretically a gravitational field to go with it, the tendency will be for gravity to work *against* expansion and work to cause the thing to implode instantly.

And yes, all that energy couples to gravity (gravity acts on all forms of energy, democratically).

Then why didn't "gravity" suck the whole thing back together again instantly? What "holds" the heat "prior to" inflation?

As for this issue of net zero energy: let me emphasize several points. First, "energy" is a term with a specific mathematical definition.

No. You keep ignoring the *physical reality* that your math attempts to describe! It isn't your math that makes it real, it is the physical process itself that makes it "real".

Namely, it's the conserved charge ("conserved" means doesn't change with time, "charge" means a quantity associated with a symmetry) for time translation invariance (which is a symmetry of the laws of physics).

The conservation "laws" apply to this energy exchange process just like they apply to *all* energy exchange processes. Energy cannot be created or destroyed, it can only change "forms". E has *always* existed as a net positive amount, evidently in the form of "heat" prior to the "bang". This universe neither created nor destroyed any energy. "Positive" amounts of energy simply transformed themselves *into* this physical universe.

 

[Michael Mozina]

I don't suppose it helps, but it's really got nothing to do with what particles hit what side of the plate and what force individual particles exert*. It is about how the energy within a volume changes. That's the solely relevant aspect of the discussion.

Actually, we seem to have a philosophical difference from the very start. IMO it has *everything* to do with what particles hit which sides of the plates. It is all about kinetic energy exchanges inside the chamber. There is energy inside the chamber that "pushes" on both sides of both plates.

In the case of Guth's near singularity blob thingy, there could be energy "pushing against" (into) his singularity if there was a "false (non) vacuum" surrounding the near singularity thing. In no case could there be "negative pressure" in the vacuum that "pulls" against the blob. There could be "heat" inside the blob that "pushes" itself into a lower energy "vacuum", but the pressure in the vacuum could not ever be "negative". The blob would have to do all the work.

Now of course you might suggest that there is an *external* EM "force" working to drive the expansion process, but the 'pressure' in a vacuum cannot be "negative". It is a physical impossibility. Even a "pure vacuum" would have a zero net energy state in terms of pressure and EM force, not a 'negative' one.

 

[edd]

Actually, we seem to have a philosophical difference from the very start. IMO it has *everything* to do with what particles hit which sides of the plates. It is all about kinetic energy exchanges inside the chamber. There is energy inside the chamber that "pushes" on both sides of both plates.

This is not a matter of philosophy. You can define things however you want, but if you choose anything other than something that is equivalent to the dE/dV definition then it's not the pressure that goes into Einstein's equations and it is not the pressure cosmologists talk about with reference to dark energy.

In the case of Guth's near singularity blob thingy, there could be energy "pushing against" (into) his singularity if there was a "false (non) vacuum" surrounding the near singularity thing. In no case could there be "negative pressure" in the vacuum that "pulls" against the blob. There could be "heat" inside the blob that "pushes" itself into a lower energy "vacuum", but the pressure in the vacuum could not ever be "negative". The blob would have to do all the work.

Again, this is not about pressure pushing or pulling to facilitate the expansion of the universe. It's about gravity and how the gravity sourced by the energy density changes as the volume changes. That's why the dE/dV definition is important.

If you choose to talk about it in any other way it's not relevant to cosmology. Whatever your philosophy.

 

[Ziggurat]

Actually, we seem to have a philosophical difference from the very start. IMO it has *everything* to do with what particles hit which sides of the plates. It is all about kinetic energy exchanges inside the chamber.

Which is why I keep asking you to define pressure, because this is not how pressure is defined, even if it's the mechanism causing pressure in a particular scenario. Whether or not Guth is right, it's still quite clear that you don't understand what pressure actually is, even in a purely classical context. Which is why you can't provide a definition.

 

[Michael Mozina]

It's unethical to read something someone wrote literally?

It is unethical to take my statements out of context and ignore my intent, yes. I was rather shocked, not at sols description, but at the idea that he was "agreeing with" a "net zero" energy universe. DRD made it sound like I did not believe his physical description. That was never the case.

The reason from my "shock" is sol seems a bit more "reasonable" on some levels that say Zig and is more direct and "honest" (I don't know of a better way to put it) than say DRD who dances around all the points entirely. In the case of sol's comment, it was not his point I was surprised by or objecting to, it was the idea he would side with the idea we were debating at the time. I knew in sols case that his own comments would eventually dismantle his own argument, and indeed, his description of "heat" seems to do just that. Sol seems like a person who thinks before he speaks, and I was simply shocked he would suggest we have a "net zero" energy universe. That is simply not the case. E has *always* exited in a "positive" energy state.

 

[Michael Mozina]

This is not a matter of philosophy. You can define things however you want, but if you choose anything other than something that is equivalent to the dE/dV definition then it's not the pressure that goes into Einstein's equations and it is not the pressure cosmologists talk about with reference to dark energy.

It's the same exact idea and description, but there is a physical process that the math relates to and describes that is equally important! We can't simply ignore the physical processes that actually generate the kinetic force and pressure on *all sides of all* the plates. There is no type of "negative pressure" inside these Casimir experiments. Such experiments are not congruent with the idea of negative pressure in a vacuum because there is pressure *and quantum force* on *both* sides of both plates.

There can be "less force" or less pressure on one side of the plate than the other, but there is no "negative pressure" or negative force on either side of any of the plates, not even at the level of QM. There are simply subatomic kinetic energy exchanges that are "higher" on one side of the plate, and "lower" on the other.

 

[edd]

It's the same exact idea and description, but there is a physical process that the math relates to and describes that is equally important! We can't simply ignore the physical processes that actually generate the kinetic force and pressure on *all sides of all* the plates.

Actually, that's (arguably) exactly what GR does. It only cares about the energy and pressure in a very general way that's quite agnostic of the low-level mechanisms.

And as a result it is in these general terms of how the energy within the volume changes that you must criticise the idea of negative pressure, in my opinion.

If you cannot argue that that is physically impossible you can't argue that dark energy is physically impossible.

 

[Michael Mozina]

Dunno.

Would you like to go through this whole thread, note the posts in which you asked them, and write up the results?

Wow. You personally do more dodging and weaving on direct questions than anyone I know.

I'll be happy to take a shot at answering such questions.

But of course you didn't answer any of them.

What I can try to do is explain what I understand contemporary cosmology, astrophysics and (parts of) physics are ... to you and any other reader*.

And yet you didn't.

Ah that "belief" thing again.

One rather fundamental difference between your apparent concept of science and mine is the role each of us considers "belief" to play in science; would it be worth exploring this perhaps?

Anything to distract the conversation from the fact you dodged all my questions again eh?

Back to unanswered questions.

Yours or mine? You didn't answer the direct questions I put to yet you expect me to respond to your questions? Why should I bother answering your questions since you dodge all of my direct questions?

Over at the space.com forum, it seems that many folk there were very unhappy with your behaviour of not answering questions (see the link I gave earlier, and follow that thread to pages 3 and 4).

Many folks? A "few" folks got all uptight at my definition of EU theory (Defined as: "MHD theory applied to objects in space"), but then I can't be responsible for the fact these few individuals did not "like" my definition. It seemed to get straightened out eventually. Why are you so worried about my *long term* conversations at a very reputable science forum where I am still an active member? Why don't you point out how you personal crucified me for not being able to answer your personal questions about light traveling through plasma over at BAUT? You can even point out how you banned me for my crimes and everything.

It seems your track record in this thread is (qualitatively) the same; in the post of mine you are quoting I gave five such questions, and since then you have had a go at answering just one.

Which of the many direct questions of mine have you answered? At least sol has the balls to put his beliefs on the line, whereas you seem to cower in the corner and take cheap shots from the bleachers.

What say you, other readers; should someone (me?) compile a list of unanswered questions?

I have limits on my time, and three, four, five, six or even seven folks to respond to in this thread each time I have time to post. There are limits on my time. What is your excuse?

Evidently you don't even buy into inflation theory, and BB theory is dead in the water without it. I don't see you putting yourself out there like sol and like edd and zig and like every other actively participating personal in this conversation. All you do is hide in the shadows and cast dispersions on me. You're a one trick pony with no scientific answers of any sort.

 

[Ziggurat]

And as a result it is in these general terms of how the energy within the volume changes that you must criticise the idea of negative pressure, in my opinion.

You're absolutely correct, but Michael just doesn't understand how to deal with something in a generalized fashion. Which is why he never understood what I meant by
[latex]$P=-\frac{\partial E}{\partial V}$[/latex]
but instead kept trying to apply the ideal gas law as if it defined pressure. If he did, he would understand that whether or not Guth is right about negative pressure really just depends upon whether or not E(V) increases with increasing V. If it does, negative pressure, if it doesn't, no negative pressure.

But of course, that takes (a little bit of) math skills to see that connection. And there's no evidence Michael has any. Hell, I've never even seen him do arithmetic, let alone any calculus.

 

[Reality Check]

There is "pressure" (iow air pressure) on both sides of the plates, and there is another QM "force" that is related to the EM field that is "pushing" on both sides of the plates! How can you *still* believe that there is "negative pressure" involved when both the air in the chamber and the photons that carry the EM field *push* against *both* sides of both plates? There is no "negative pressure" in a vacuum, just "positive pressure" pushing on both sides of the plates, and positive force pushing on both sides of the plates?

You are still babbling about air pressure in the vacuum chamber.
Can I take that you have reverted to your previous idea that experimental physicists are stupid, do not know about this and do not calibrate their apparatus to negate this effect?

I get the distinct impression by the way that this issue relates directly back to Guth's "reheating problem". If the vacuum actually had "negative pressure" and stayed that way throughout the process, it would have never stopped, the "bubbles" (of unknown substance) would not "push" against each other, and nothing would "reheat".

The Casimir stuff is what you tried to use to justify your claim about "negative pressure in a vacuum". There is no such thing going on. There is "pressure" (air pressure) that pushes on both sides of the plates, and "force" related to QM that pushes on *both* sides of the plates!

No. The Casimir effect is just an example of negative pressure. Actual science tells us that negative pressure exists. This is not a claim - it is a fact of nature.
Your problem seems to be that you have never personally experienced negative pressure and so do not think it exists.
Our problem is that we know the equations that define pressure (and note that they allow pressure with any sign) and trust the experimental results that measure negative pressure. Silly us !

How can anyone here still be defending the idea that a vacuum can have negative pressure? It's physically *impossible* for that to happen.

Negative pressure is not physically impossible because it is detected, e.g.

• The transpiration pull of plants.
• In measurements of the Casimir effect.

In any case you still have not answered either question. Since the Casimir quetion is so tough for you that you did not notice the word net in it

So is this what you are saying:

• If the plates are such that the NET force is replusive then the NET pressure (force divided by area) is positive.
• If the plates are such that the NET force is attractive then the NET pressure is still positive despite the fact that the net force has changed sign.

If so your conclusion must be that the area of the plates must have also changed sign to keep the pressure positive. Can you tell us how to measure a negative area? Do we construct square plates with imaginary sides and square their imaginary lengths?

Here is a simpler situation (first asked 26 March 2009):

Consider these 2 scenarios

1. A force F pushes on a surface that has an area of A.
2. A force F pulls on a surface that has an area of A.

What is the pressure in these 2 scenarios?
​

If you do not know what pressure is or cannot answer that then:

Is the pressure positive or negative in each of the 2 scenerios?
​

 

[Michael Mozina]

Actually, that's (arguably) exactly what GR does. It only cares about the energy and pressure in a very general way that's quite agnostic of the low-level mechanisms.

Ah, but nature is not "agnostic" when it comes to the operation of it's low level physical mechanisms. GR is just a mathematical model that may or may not accurately describe the physical functions of the universe. Perhaps GR theory will one day be replaced with a quantum description of gravity. The physical processes that drive gravity will determine whether or not GR is ultimately replaced with a new mathematical model. There is a "physical reality" that these mathematical models attempt to accurately model.

And as a result it is in these general terms of how the energy within the volume changes that you must criticise the idea of negative pressure, in my opinion.

Which "volume" are we talking about? The total "volume" in the Casimir chamber is unchanged by the pushing together of the plates inside the chamber. How does the notion of volume help your case?

If you cannot argue that that is physically impossible you can't argue that dark energy is physically impossible.

I'm not sure how to even treat "dark energy" since it seems to be nothing more than a "new fancy label" to describe "acceleration". I don't see why "acceleration" needs a "fancy new placeholder label' to begin with. As it relates however to "negative pressure", nothing like that is possible in a vacuum due to the existing kinetic energy inside the vacuum.

 

[Ziggurat]

Which "volume" are we talking about? The total "volume" in the Casimir chamber is unchanged by the pushing together of the plates inside the chamber. How does the notion of volume help your case?

You really don't know, do you? The volume in question is the volume of space between the plates, and it rather obviously changes with separation distance. Yet again, you reveal that you don't understand even basic aspects of what's under discussion.

I'm not sure how to even treat "dark energy"

Well, you got one thing right.

 

[Michael Mozina]

You are still babbling about air pressure in the vacuum chamber.

I'm still noting that even the best vacuums on Earth and in space have "air pressure" in them. They have QM "pressure" too I suppose if you wish to call a "FORCE" (kinetic energy of photons, neutrinos, etc) a "pressure". At no point does a vacuum contain even "zero" pressure, let alone "negative pressure".

Can I take that you have reverted to your previous idea that experimental physicists are stupid, do not know about this and do not calibrate their apparatus to negate this effect?

Where do you guys get off making such wild accusations, particularly after I "praised" the folks that described the Casimir effect on WIKI, right down to the images they used? They obviously knew what they were talking about when they called it a "force" and you ignored it. They obviously know what they were talking about when they described the "force" as it affected *both sides* of *both plates*, and you ignored that too. They aren't stupid.

No. The Casimir effect is just an example of negative pressure.

No, it is NOT! It is an example of *force* being applied to *both sides* of *both plates* where where the force is "greater" on one side than the other. It's all done inside a "positively pressurized" chamber!