Lambda-CDM theory - Woo or not?

[Reality Check]

In one of these threads we went through Alfven's "Bang" theory and it simply started with on isotropic layout of matter and antimatter. The isotropic feature isn't the be- all-end-all that you seem to imagine it to be.

Wrong again MM.
A theory that starts with an " isotropic layout of matter and antimatter" is wrong.
The CMBR is nearly isotropic. It has variations of ~1 part in 10,000. This is an important fact about the universe that you really need to learn.

 

[Michael Mozina]

You are confused, Michael, as usual. The "lambda" in Lambda-CDM is an extra, constant term in the curvature of spacetime. It is NOT " ... and the curvature comes from a Higgs-like scalar field" or "... and the curvature comes from an extra inflaton" or "... and the curvature is just how the Universe happens to be". The Lambda-CDM hypothesis is that there's a constant curvature there, period.

And that constant curvature is caused by what exactly?

(If someone were to argue, "I agree that there's curvature there but I disagree that it's a dark energy", that could be an intelligent discussion. I presume you aren't making that argument; you never have. Your argument is more in the "everything is wrong" camp.)

Well, maybe that is the appropriate discussion at this point because there seems to be a bit of "bait and switch" going on between the terms "dark energy" (which I was dissing) and "lambda" as you describe it. Let's talk "cause/effect" and explain why lambda is there for me.

When astronomers claim that 70+ percent of the universe is made of "dark energy', how is that related to what you're calling "lambda"?

I can't really answer much of the rest of your post until I understand what you believe that constant is related to and how it relates to "dark energy". If you recall I don't have a problem with "acceleration", just "dark energy".

 

[Skwinty]

A theory that starts with an " isotropic layout of matter and antimatter" is wrong.

If that was right we would not be discussing this right now

 

[Michael Mozina]

That is just idiotic.
Many people in this forum have tried to explain the physical reality of negative pressure to you (it is measured in Casimir effect experiments!).

No. I've been there and done that with you. The Casimir effect would not exist were it not for the carrier particle of the EM field inside the vacuum. Since it can be repulsive as well as attractive, your claim is meaningless. There is no such thing as "negative pressure in a vacuum". The very best we can ever hope to achieve is a "near vacuum", one with some amount of positive pressure. Even if we could remove every physical thing and type of energy from the vacuum, it would simply achieve a "zero" pressure state. There is nothing you can add or subtract from that pure vacuum to achieve a "negative pressure".

Get over it.

 

[ben m]

When astronomers claim that 70+ percent of the universe is made of "dark energy', how is that related to what you're calling "lambda"?

Do you agree, then, that there's overwhelming evidence that the curvature term (lambda) is part of the geometry of spacetime in which supernovae, galaxies, and CMB photons move?

If you don't understand the basic facts that "GR curvature causes accelerations" and "the observed accelerations match this particular type of curvature" then I see no point discussing the details of that curvature with you. If you're going to pull out "I think the Hubble curve is caused by EM forces, not curvature, and the CMB photons are emitted by the CNO cycle" or some crap like that, then ... well, if you don't think there's curvature there at all, then I don't care about your general views of the curvature/energy relationship.

 

[W.D.Clinger]

And that constant curvature is caused by what exactly?

I don't know, but vacuum energy^WP is a leading contender. You'll reject that, of course, because it's related to the Casimir effect^WP.

Well, maybe that is the appropriate discussion at this point because there seems to be a bit of "bait a switch" going on between the terms "dark energy" (which I was dissing) and "lambda" as you describe it. Let's talk "cause/effect" and explain why lambda is there for me.

I'm sorry, but why do you think lambda is there for you?

I can't really answer much of the rest of your post until I understand what you believe that constant is related to and how it relates to "dark energy". If you recall I don't have a problem with "acceleration", just "dark energy".

Sounds as though it's time for you to answer Perpetual Student's repeated question concerning your interpretation of the Einstein field equations^WP, paying particular attention to the lambda term.

 

[DeiRenDopa]

No. I've been there and done that with you. The Casimir effect would not exist were it not for the carrier particle of the EM field inside the vacuum. Since it can be repulsive as well as attractive, your claim is meaningless. There is no such thing as "negative pressure in a vacuum". The very best we can ever hope to achieve is a "near vacuum", one with some amount of positive pressure. Even if we could remove every physical thing and type of energy from the vacuum, it would simply achieve a "zero" pressure state. There is nothing you can add or subtract from that pure vacuum to achieve a "negative pressure".

Get over it.

(bold added)

You do realise, don't you MM, that, per the "empirical, controlled experiments in the lab" basis for all physics you've steadfastly adhered to since forever, "the carrier particle of the EM field inside the vacuum" is not real?

In fact, it's worse than that, it's a - what did you call it? - "metaphysical entity", or "metaphysical baggage"; it's just "a "gap filler' to support an otherwise falsified theory", ""speculative" math, completely devoid of "qualification"", and so on.

How can this "metaphysical entity" be shown to be not real, by "empirical, controlled experiments in the lab"?

Easy!

Do the Casimir effect experiment inside a big Faraday cage.

 

[ben m]

No. I've been there and done that with you. The Casimir effect would not exist were it not for the carrier particle of the EM field inside the vacuum. Since it can be repulsive as well as attractive, your claim is meaningless. There is no such thing as "negative pressure in a vacuum". The very best we can ever hope to achieve is a "near vacuum", one with some amount of positive pressure. Even if we could remove every physical thing and type of energy from the vacuum, it would simply achieve a "zero" pressure state. There is nothing you can add or subtract from that pure vacuum to achieve a "negative pressure".

By your tone, I presume that you have already phoned up PRL and they've retracted all of their quantum-mechanics papers, including of course the Casimir ones, because nobody had thought about vacuums until you came along?

Once you've done that, I will telephone the mouldering corpse of Werner Heisenberg---I have his number around here somewhere---and tell him that Michael Mozina has a zero-uncertainty idea about the energy of something.

Seriously, though. There is an honest way to make a science statement that you know (as you do) is subject to dispute. "Get over it" is not that way.

 

[Michael Mozina]

Do you agree, then, that there's overwhelming evidence that the curvature term (lambda) is part of the geometry of spacetime in which supernovae, galaxies, and CMB photons move?

That's an interesting question. I feel like I'm stepping around some land mines here so bear with me. I would go so far as to agree that there could be something physical which manifests itself over time as something you are calling a "curvature term that is a part of the geometry of spacetime". I'm not necessarily convinced that it is actually a curvature of spacetime as you seem to be.

I still need you to address the 'cause/effect' question for me, and how that leads astronomers to believe that 72% of the universe is made of "dark energy"?

 

[Michael Mozina]

I don't know, but vacuum energy^WP is a leading contender. You'll reject that, of course, because it's related to the Casimir effect^WP.

If you're implying that the EM energy related to the EM field of the universe is responsible, well, "ok". Otherwise what does the Casimir effect have to do with anything?

I'm sorry, but why do you think lambda is there for you?

I'm trying to get you to explain why it's not zero.

 

[ben m]

That's an interesting question. I feel like I'm stepping around some land mines here so bear with me. I would go so far as to agree that there could be something physical which manifests itself over time as something you are calling a "curvature term that that is a part of the geometry of spacetime". I'm not necessarily convinced that it is actually a curvature of spacetime as you seem to be.

Um. So you want to invent a new force that causes long-range, equivalence-principle-obeying acceleration and gravitational redshifts? Sure, go for it. The result would be called a "hypothesis". Add as many free parameters as you think you need; when you have something you want to compare to data, we have mathematical tests which will tell you if you've added too many parameters; this is part of "hypothesis testing". See if you can beat Lambda-CDM, which has very few free parameters.

I still need you to address the 'cause/effect' question for me, and how that leads astronomers to believe that 72% of the universe is made of "dark energy"?

Seriously, Michael, you've heard this a million times. You've presumably ignored it all those times. You've refused to pick up any of the 100 astro textbooks or 1000 articles that would explain it to you. So I presume you're preparing to ignore me too.

In a nutshell---the direct evidence says two things. (a) GR is true in general and (b) the Universe has this constant-curvature term in its geometry. That's it. That's what astronomers "believe", and that's what they mean when they put the 75% or whatever in their equations---it means the constant-curvature term is 75% of the total curvature. Understand?

"Dark energy" is a shorthand name for this curvature, because if you do some easy algebra on the EFE the curvature term gets moved to the right and picks up the units of energy density. Dark energy, lambda, cosmological constant ... the data says "there's a constant term in the EFE" and we have to have a name for it. These are the standard names. Get used to it.

Do you want to know where the curvature comes from? We don't have a real hypothesis, we have speculations; they are probably over your head by a grade level or two. Learn the prerequisites first and maybe you'll graduate to the fancy stuff.

 

[Michael Mozina]

Do you want to know where the curvature comes from? We don't have a real hypothesis, we have speculations; they are probably over your head by a grade level or two. Learn the prerequisites first and maybe you'll graduate to the fancy stuff.

Non responsive ben. Shame on you.

 

[W.D.Clinger]

I don't know, but vacuum energy^WP is a leading contender. You'll reject that, of course, because it's related to the Casimir effect^WP.

If you're implying that the EM energy related to the EM field of the universe is responsible, well, "ok". Otherwise what does the Casimir effect have to do with anything?

No, that's not what I'm implying. I'm suggesting that vacuum energy^WP, as implied by quantum mechanics, may be the "cause" of a non-zero cosmological constant (lambda).

I'm trying to get you to explain why it's not zero.

Because the zero-point energy^WP of the vacuum isn't zero.

ETA: Just in case it wasn't clear, I'm offering speculative explanations in response to Michael Mozina's request to speculate about possible causes for a non-zero cosmological constant. My speculations should not be confused with the empirical evidence for dark energy, for which a non-zero cosmological constant is one possible explanation.

 

[ben m]

I'm trying to get you to explain why it's not zero.

It is a fact that lambda is not zero. If lambda were zero, the data would not be what they are. "Lambda is nonzero" is a fact which the Universe has handed to us. The next step is figuring out why it's nonzero.

 

[Michael Mozina]

No, that's not what I'm implying. I'm suggesting that vacuum energy^WP, as implied by quantum mechanics, may be the "cause" of a non-zero cosmological constant (lambda).


Because the zero-point energy^WP of the vacuum isn't zero.

None of that is at odds with an EU oriented theory. None of it has anything at all to do with "dark energy".

 

[Ziggurat]

None of that is at odds with an EU oriented theory.

But thermodynamics is. You have yet to even suggest a possible resolution to the conflict between thermodynamics and EU theories.

 

[W.D.Clinger]

I'm suggesting that vacuum energy^WP, as implied by quantum mechanics, may be the "cause" of a non-zero cosmological constant (lambda).

None of it has anything at all to do with "dark energy".

False. From the Wikipedia article on dark energy^WP:

Two proposed forms for dark energy are the cosmological constant...and scalar fields...whose energy density can vary in time and space....The cosmological constant is physically equivalent to vacuum energy.

If you wish to argue with that, then you owe us your alternative explanation of the role of the cosmological constant^WP in the Einstein field equations^WP.

 

[ben m]

None of that is at odds with an EU oriented theory.

Easy to say that, isn't it? Just slips right out. I can do it too: "None of your fossil-record stuff is at odds with my Young Earth theory". You can make anything sound consistent. "None of your ballistics data is at odds with my Kennedy-alien-assassination theory". Easy as pie to say that.

You know what's harder? Actually writing down a theory in enough detail to be compared to data. Has EU/PC done that yet? Like this? http://pdg.lbl.gov/2009/reviews/rpp2009-rev-cosmological-parameters.pdf

 

[Reality Check]

No. I've been there and done that with you. ...usual MM rant about negative pressure....

Get over it.

No. I've been there and done that with you.
There is such a thing as negative pressure in a vacuum.

Get over it.

 

[DeiRenDopa]

None of that is at odds with an EU oriented theory.

There is no such thing!

This "metaphysical entity" has never been shown to be real, by "empirical, controlled experiments in the lab"!!

Seriously MM, when are you going to roll up your sleeves and develop something that's falsifiable? Heck you could even start simple, like showing that Mozeparation is real, by empirical, controlled experiments in the lab, or knocking up some Mozplasma in your lab (I, for one, appreciate that developing an EU cosmological model that is fully consistent with the billions of astronomical observations - of things like the Hubble relationship, the CMB, primordial abundance of light nuclides, BAO, large-scale structure, Olbers' paradox, etc - is a far, far, far more difficult task than merely demonstrating the existence of Moztronium).