Lambda-CDM theory - Woo or not?

[Michael Mozina]

Weyl concludes §34 as follows:

In the latter case we have a static world that cannot exist without a mass-horizon; this assumption...is favoured by Einstein.

Einstein's lambda was physically "qualified" Mr. Spock. He believed in an infinite, eternal, static universe, not "big bang" theory. He presumed that "external mass" kept the whole thing static.

Dark energy however isn't "qualified", nor is "inflation'. You still have a "qualification" problem that is unrelated to the equations themselves. As long as you can physically and empirically justify your lambda, you're welcome to use it. If however you set it to anything other than zero, you have to qualify your lambda via physics. We can drop an object and justify Einstein's lambda. How do we justify dark energy or inflation as "causes" of lambda in an empirical manner?

 

[ben m]

Einstein's lambda was physically "qualified" Mr. Spock. He believed in an infinite, eternal, static universe, not "big bang" theory. He presumed that "external mass" kept the whole thing static.

Dark energy however isn't "qualified", nor is "inflation'. You still have a "qualification" problem that is unrelated to the equations themselves. As long as you can physically and empirically justify your lambda, you're welcome to use it. If however you set it to anything other than zero, you have to qualify your lambda via physics. We can drop an object and justify Einstein's lambda. How do we justify dark energy or inflation as "causes" of lambda in an empirical manner?

I (foolishly) repeat my question:

Which of the following arguments are you making ABOUT DARK ENERGY (leave primordial inflation aside for a moment)? I really can't tell. Answer clearly.

a) "The cosmology data clearly shows a cosmological constant curvature BUT the mainstream view is incorrect/premature/moronic in saying that this curvature is due to dark energy." (ETA2: your "we can drop an object and verify Einstein's lambda" might mean something in this direction.)

b) "The cosmology data can't say anything about curvature/spacetime effects to begin with. I think the observed acceleration is due to non-gravity forces."

c) "Don't ask me, I am just a Perl script with a collection of anti-cosmology text snippets which I cut-and-paste using simple heuristics."

ETA: or

d) "I haven't decided which of these I am believe. At various times I will believe whichever one appears to make me win the argument of the moment."

 

[W.D.Clinger]

This is an example of what ben m called a Type A Mozconception discussion, in which members of this forum attempt to explain standard physics to someone who is determined not to understand it.

Einstein's lambda was physically "qualified" Mr. Spock. He believed in an infinite, eternal, static universe, not "big bang" theory. He presumed that "external mass" kept the whole thing static.

Six points:

1. GeeMack should add "qualified" to the list of words you use but are unable or unwilling to define.
2. If you're going to talk about Einstein's beliefs as though they were as arbitrary and/or religious as your own, then you should at least be willing to admit that Einstein later repented of those beliefs.
3. Einstein's beliefs led him to postulate a non-zero value for lambda.
4. Einstein had no empirical justification for the "external mass" he presumed.
5. Einstein and Stern were the first to recognize that quantum mechanics implies a zero-point energy^WP of ½hν>0 for oscillators at absolute zero. That in turn led to recognition that the vacuum energy^WP should also be positive.
6. Positive vacuum energy is a form of dark energy^WP.

Dark energy however isn't "qualified", nor is "inflation'. You still have a "qualification" problem that is unrelated to the equations themselves. As long as you can physically and empirically justify your lambda, you're welcome to use it. If however you set it to anything other than zero, you have to qualify your lambda via physics. We can drop an object and justify Einstein's lambda. How do we justify dark energy or inflation as "causes" of lambda in an empirical manner?

Many people here have directed you to multiple observations and experiments that justify dark energy and/or inflation. Your determination to ignore that empirical evidence has not made it disappear.

We'd all like to be entertained by your explanation of how "we can drop an object and justify Einstein's lambda". If it's so easy to provide empirical support for a non-zero cosmological constant, then why have you argued so doggedly against a non-zero cosmological constant?

Finally, you still haven't caught on to the fact that a non-zero value for that cosmological constant implies dark energy and (for the particular range of non-zero values implied by observation) some degree of inflation as well.

 

[sol invictus]

• Einstein and Stern were the first to recognize that quantum mechanics implies a zero-point energy^WP of ½hν>0 for oscillators at absolute zero. That in turn led to recognition that the vacuum energy^WP should also be positive.
• Positive vacuum energy is a form of dark energy^WP.

Those two aren't quite right. Bosonic modes give you ½hν. But fermions give you -½hν for a mode with frequency ν. That's why supersymmetric theories have zero vacuum energy (the fermionic contribution cancels the bosonic contribution), and it means that the vacuum energy in general can have either sign. If it were negative, it would still be dark energy in the sense that it doesn't redshift, but it would cause a contraction and eventually a big crunch rather than an accelerated expansion.

 

[edd]

A new review out today - http://arxiv.org/abs/1005.3765
"Evidence for the Fifth Element Astrophysical status of Dark Energy"

 

[Reality Check]

Einstein's lambda was physically "qualified" Mr. Spock. He believed in an infinite, eternal, static universe, not "big bang" theory. He presumed that "external mass" kept the whole thing static.

Most scientists thought that the universe was infinite, eternal and static before 1929 and Hubble's discovery. Most now think that evidence that the universe was in a hot dense state is overwhelming. One reason that Einstein added lambda was to allow for the possibility of a static universe.

The real reason that he added it is that it was part of the mathematics. When you take the Einstein field equations to their Newtonian limit any constant term vanishes. So to make GR mathematically complete and still compatible with Newtonian gravity you have to include lambda.

Dark energy however isn't "qualified", nor is "inflation'.

The effects of dark energy are measured - it is quanitfied.
The effects of inflation are measured - it is quanitfied.

 

[GeeMack]

1. GeeMack should add "qualified" to the list of words you use but are unable or unwilling to define.

Yes, as well as several others from his posts below.

So [...]

What neither of you did [...]

Ya, and [...]

Michael applies meanings different than the common usage for the words and phrases he puts in quote marks. Below is an ongoing list of terms which he uses but is unable or unwilling to define. Until he can define these terms, all of his arguments using any of them are unintelligible blathering.

• absolute
• acceleration
• act of faith
• ad hoc
• assumed
• background
• ballpark
• bang
• believer
• best
• better
• caught on
• cause
• cause/effect
• confused
• control mechanism
• correct
• creativity
• dark energy
• dark energy of the gaps
• dark matter
• dead
• decent
• discovery
• emotional
• empirical science
• empirically
• empirically demonstrated
• extra energy
• flavors
• hairy inflation
• ignore anything that falsifies the concept of exotic matter
• ignore the cause of the lambda
• in the ballpark
• inflation
• invented
• it's not my fault
• lab tested
• lamba
• logically impossible
• mathematical perfection
• measurable
• metaphysical baggage
• narrow the range
• negative
• negative pressure
• negative pressures in a vacuum
• no show
• observed acceleration
• physics in general
• popular
• positive pressure vacuum
• postdicted
• postdicting a fit
• predicted
• pretend
• pretend entities
• properties
• put faith
• qualification
• relative
• religion
• ruled in
• scale
• science
• sciences
• simplicity
• spin
• superiority
• test
• throw it out
• tweak
• tweaked
• tweaked to fit
• unseen
• unseen entities
• unusual
• verification
• verify
• woo
• zero

 

[DeiRenDopa]

The basic problem is simple. You *refuse* to consider the one force of nature that is known to be 39 OOM more powerful than gravity.

OK, just for fun, and once more^, I'm going to consider this more powerful force.

The electron has a mass of 9.1x10^-31 kg, and a charge of -1.6x10^-19 C, giving it a charge-to-mass ratio of 1.8x10^11 C/kg (ignoring the sign).

The Sun has a mass of 2x10^30 kg; if it had a charge/mass ratio the same as that of the electron, it would have a charge of 3.6x10^41 C.

But the Sun is not a single lepton; rather it is composed of a great many leptons and hadrons, which interact with each other. Specifically, the charged particles interact via the electromagnetic force.

Let's simplify this, and look at only the electrostatic forces (like charges repel, opposite charges attract, the force is proportional to the product of the charges, and inversely proportional to the distance between them squared).

Let's also assume, to begin, that the charge is all on the surface of the Sun, and it is net negative.

Looking at a single electron near the surface of our toy Sun, the force on it due to gravity is 2.5x10^-28 N.

How far away would another electron have to be for the electrostatic force to equal the gravitational one (in magnitude)? I'll let you do this calculation MM; if you don't know the necessary formulae, just say so. Anyway, the result I get is ~1 m.

So, at an OOM level, the Sun could have ~1 electron per square meter on its surface and just barely hold onto those electrons, gravitationally. That means the Sun could have a net charge of ~1 C. That's ~41 OOM smaller than the charge the Sun would have if it had the same charge/mass ratio as the electron.

As with my quick calculation in the Aether batteries thread, I'd like MM to check my working, both the arithmetic and the application of the formulae. If you would, please MM, point out any mistakes I've made. Note that the math you need to any of these calculations, and check my working, is limited to arithmetic and very simple algebra.

Having done that, can you - MM - suggest any tweaks I should make in the above, to make my demonstration of the dominance of gravity over electromagnetism more realistic (as it applies to the real Sun)?

^ the many threads in which MM (and others) has made this claim contain many examples, from many different people, of considering this ... together with their findings.

 

[Michael Mozina]

If you're going to talk about Einstein's beliefs as though they were as arbitrary and/or religious as your own, then you should at least be willing to admit that Einstein later repented of those beliefs.

I believe you still missed my point. Einstein's formulas are not the problem. Einstein used those formulas "properly" too, lambda and all. When he did attempt to insert a non zero lambda, he used a *KNOWN FORCE OF NATURE*! He did not "invent" a fictitious force of nature to insert into lambda as was done with inflation and dark energy. Do you see and understand this distinction?

If I arbitrarily stuff magic into lambda, it's no longer "physics", it's "pseudoscience". Since you never qualified your lambda in any logical way, it's "pseudoscience", or IMO "woo with make believe math".

 

[sol invictus]

I believe you still missed my point. Einstein's formulas are not the problem. Einstein used those formulas "properly" too, lambda and all. When he did attempt to insert a non zero lambda, he used a *KNOWN FORCE OF NATURE*!

Nonsense. There was no observational evidence for any such force at the time, and there certainly wasn't any corresponding "KNOWN FORCE OF NATURE".

He did not "invent" a fictitious force of nature to insert into lambda as was done with inflation and dark energy.

That's exactly what he did. The difference is that he had no observational evidence on which to base that, whereas now we have very strong evidence for both inflation and dark energy.

 

[GeeMack]

I believe [...]

New words added...

Michael applies meanings different than the common usage for the words and phrases he puts in quote marks. Below is an ongoing list of terms which he uses but is unable or unwilling to define. Until he can define these terms, all of his arguments using any of them are unintelligible blathering.

• absolute
• acceleration
• act of faith
• ad hoc
• assumed
• background
• ballpark
• bang
• believer
• best
• better
• caught on
• cause
• cause/effect
• confused
• control mechanism
• correct
• creativity
• dark energy
• dark energy of the gaps
• dark matter
• dead
• decent
• discovery
• emotional
• empirical science
• empirically
• empirically demonstrated
• extra energy
• flavors
• hairy inflation
• ignore anything that falsifies the concept of exotic matter
• ignore the cause of the lambda
• in the ballpark
• inflation
• invent
• invented
• it's not my fault
• lab tested
• lamba
• logically impossible
• mathematical perfection
• measurable
• metaphysical baggage
• narrow the range
• negative
• negative pressure
• negative pressures in a vacuum
• no show
• observed acceleration
• physics
• physics in general
• popular
• positive pressure vacuum
• postdicted
• postdicting a fit
• predicted
• pretend
• pretend entities
• properly
• properties
• pseudoscience
• put faith
• qualification
• relative
• religion
• ruled in
• scale
• science
• sciences
• simplicity
• spin
• superiority
• test
• throw it out
• tweak
• tweaked
• tweaked to fit
• unseen
• unseen entities
• unusual
• verification
• verify
• woo
• woo with make believe math
• zero

 

[Michael Mozina]

Nonsense. There was no observational evidence for any such force at the time, and there certainly wasn't any corresponding "KNOWN FORCE OF NATURE".

Huh? Gravity shows up in all experiments on Earth sol, every single one. It's not a no show in the lab like inflation and dark energy. if I point at an observation of acceleration and chalk it up to "gravity", I have not chalked it up to anything new. I have made no special claims. If however I point to that same observation of acceleration and claim "Mozflation did it", I need to "qualify" Moflation, or my theory is 'woo'.

That's exactly what he did. The difference is that he had no observational evidence on which to base that, whereas now we have very strong evidence for both inflation and dark energy.

No! He used "gravity" to explain his lambda! He did not "create" a fictitious force of nature like Moflation! You only have observational evidence of lambda sol, you have no evidence that lambda has anything to do with "hairy moflation"!

 

[GeeMack]

Huh? [...]

More words added...

Michael applies meanings different than the common usage for the words and phrases he puts in quote marks. Below is an ongoing list of terms which he uses but is unable or unwilling to define. Until he can define these terms, all of his arguments using any of them are unintelligible blathering.

• absolute
• acceleration
• act of faith
• ad hoc
• assumed
• background
• ballpark
• bang
• believer
• best
• better
• caught on
• cause
• cause/effect
• confused
• control mechanism
• correct
• create
• creativity
• dark energy
• dark energy of the gaps
• dark matter
• dead
• decent
• discovery
• emotional
• empirical science
• empirically
• empirically demonstrated
• extra energy
• flavors
• gravity
• hairy inflation
• hairy moflation
• ignore anything that falsifies the concept of exotic matter
• ignore the cause of the lambda
• in the ballpark
• inflation
• invent
• invented
• it's not my fault
• lab tested
• lamba
• logically impossible
• mathematical perfection
• measurable
• metaphysical baggage
• narrow the range
• negative
• negative pressure
• negative pressures in a vacuum
• no show
• observed acceleration
• physics
• physics in general
• popular
• positive pressure vacuum
• postdicted
• postdicting a fit
• predicted
• pretend
• pretend entities
• properly
• properties
• pseudoscience
• put faith
• qualification
• qualify
• relative
• religion
• ruled in
• scale
• science
• sciences
• simplicity
• spin
• superiority
• test
• throw it out
• tweak
• tweaked
• tweaked to fit
• unseen
• unseen entities
• unusual
• verification
• verify
• woo
• woo with make believe math
• zero

 

[W.D.Clinger]

Those two aren't quite right. Bosonic modes give you ½hν. But fermions give you -½hν for a mode with frequency ν. That's why supersymmetric theories have zero vacuum energy (the fermionic contribution cancels the bosonic contribution), and it means that the vacuum energy in general can have either sign. If it were negative, it would still be dark energy in the sense that it doesn't redshift, but it would cause a contraction and eventually a big crunch rather than an accelerated expansion.

Thanks for the correction. I know nothing about particle physics.

A new review out today - http://arxiv.org/abs/1005.3765
"Evidence for the Fifth Element Astrophysical status of Dark Energy"

Page 28 says:

An elegant solution to this problem is obtained from super-symmetry: the contribution to vacuum from fermion is negative and therefore with an equal number of modes in fermions and bosons one gets a cancellation. However, because the supersymetry should be broken at energy below 1 TeV or so, the problem of the vacuum density is still not solved, even if its strength has been noticeabily reduced.

The following paper contains a proposal along those lines and refers to experimental tests in progress:
http://arxiv.org/abs/astro-ph/0703364

By the way, I can't agree with the statement on page 2 that Friedmann's "work has remained totally unnoticed".

When you take the Einstein field equations to their Newtonian limit any constant term vanishes. So to make GR mathematically complete and still compatible with Newtonian gravity you have to include lambda.

Any constant term must vanish at the Newtonian limit. Since non-zero constant terms don't actually vanish, the correspondence with Newtonian physics imposes an upper bound on lambda: It must be too small to make a difference at scales for which the Newtonian approximation is appropriate.

I believe you still missed my point. Einstein's formulas are not the problem. Einstein used those formulas "properly" too, lambda and all. When he did attempt to insert a non zero lambda, he used a *KNOWN FORCE OF NATURE*! He did not "invent" a fictitious force of nature to insert into lambda as was done with inflation and dark energy. Do you see and understand this distinction?

No. It looks like gibberish to me. In particular, there is no "*KNOWN FORCE OF NATURE*" to which you could be referring that would not be equally appropriate for a lambda-CDM model.

By the way, I erred by saying Einstein added the lambda-term in 1915. He added it in 1917. His primary motivation was de Sitter's proof that his original equations had no static solution. Although the lambda-term allowed a static solution, that solution is unstable. After Hubble formulated Hubble's Law^WP, indicating expansion of the universe, Einstein came to regard his addition of the lambda-term as the greatest blunder of his career. Observational evidence for dark energy^WP has restored scientific interest in the cosmological constant^WP.

If I arbitrarily stuff magic into lambda, it's no longer "physics", it's "pseudoscience". Since you never qualified your lambda in any logical way, it's "pseudoscience", or IMO "woo with make believe math".

Since you have never defined "qualified" or "arbitrarily stuff magic into lambda" in any logical way, you're talking gibberish.

 

[DeiRenDopa]

Huh? Gravity shows up in all experiments on Earth sol, every single one.

For the benefit of newcomers to MM's views on "*KNOWN FORCE OF NATURE*", there is at least one, long, older JREF thread which includes a highly pertinent, lengthy discussion (if that's the right word) - the same one involving the Casimir effect (I think).

MM's perspective on this illustrates nicely the distinction between looking at the world with Aristotelian glasses and Newtonian ones.

Let's look at this: "Gravity shows up in all experiments on Earth" (we'll leave aside for now the millions of experiments on Earth in which gravity does not show up, for example the two-slit experiment).

Perhaps the simplest "shows up" is that things fall. But not all things fall (helium filled balloons, for example, or wood in water), or not always (leaves on a windy day, for example, or clouds). And even for things which do fall, they don't do so in the same way (a feather falls more slowly than a ball of lead, for example).

So how do you get "*KNOWN FORCE OF NATURE*" from things (sorta, sometimes) falling?

One way is to do what Galileo did - conduct controlled experiments, with hypotheses and quantification.

Another way is to do what Newton did - conduct thought experiments, with oodles of quantitative data (courtesy of Kepler, and others) and math.

What results is, indeed, a "*KNOWN FORCE OF NATURE*" ... but it is a *quantitative* one, not a qualitative one! Take away the quantification, and there is no "*KNOWN FORCE OF NATURE*", just Aristotelian logic with no possibility of falsification.

So what is a belief in the existence of gravity as a "*KNOWN FORCE OF NATURE*", in the absence of quantification? Surely it must be the very essence of "ad hoc", of "arbitrary", or even of dogma.

It is, I think, but a short stretch from here to a religious belief - gravity as "*KNOWN FORCE OF NATURE*" is sacred.

 

[DeiRenDopa]

One more thing: MM has a rather odd view of physics, in that it has no historical dimension (to him).

For example, gravity as a "*KNOWN FORCE OF NATURE*", in the form Newton proposed, was not tested 'in the lab' until well after his death (first by Cavendish, who weighed the Earth), and its consistency over a wide range of masses and distances not until the Eot-Wash experiments (and similar), late last century!

Similarly, for GR as a theory of gravity, 'lab testing' wasn't done until ~half a century after Einstein's publication of it (and the observation of deflection of light by the Sun, in the 1919 eclipse, thus confirming a prediction).

Think of what an MM-clone would have written, between Newton and Cavendish for example, or Einstein and Pound-Rebka! To MM, gravity as a "*KNOWN FORCE OF NATURE*" is a-historic, and one implication is particularly relevant to this thread: GR is the one, only, and final theory of gravity! There can be no successor, no tweaking or modification, no falsification, nothing; it is immutable, and all physicists must believe in it, with fervour.

Well, not exactly.

The only way GR can be modified is via experiments - "controlled" ones, of course - done in labs here on Earth (in the MM view of physics).

 

[Kwalish Kid]

No! He used "gravity" to explain his lambda! He did not "create" a fictitious force of nature like Moflation! You only have observational evidence of lambda sol, you have no evidence that lambda has anything to do with "hairy moflation"!

All of the evidence for dark energy so far are a) entirely consistent with "dark energy" being nothing other than a constant of the Einstein Field Equation and b) almost entirely independent of inflation.

There are additional hypotheses that go beyond this and there are additional research projects to attempt to find observational evidence for these hypotheses.

 

[ben m]

MM wants to use statements like "you only have evidence for lambda" because he thinks they'll win this argument for him. But they're not very clear or unambiguous statements---I think he expects to need to weasel out of them later.

Michael, can you make an explicit and un-weasel-able statement for a change? Do you or do you not think that the evidence supports the presence of a constant-curvature term in the gravitational evolution of the Universe?

 

[sol invictus]

Huh? Gravity shows up in all experiments on Earth sol, every single one. It's not a no show in the lab like inflation and dark energy. if I point at an observation of acceleration and chalk it up to "gravity", I have not chalked it up to anything new. I have made no special claims. If however I point to that same observation of acceleration and claim "Mozflation did it", I need to "qualify" Moflation, or my theory is 'woo'.



No! He used "gravity" to explain his lambda! He did not "create" a fictitious force of nature like Moflation! You only have observational evidence of lambda sol, you have no evidence that lambda has anything to do with "hairy moflation"!

Michael, there is no difference between what Einstein did - add something to his theory of gravity to provide a repulsive force - and what modern astronomers have done (add exactly the same thing to Einstein's theory, except with a smaller numerical magnitude), except that Einstein had no observational evidence for lambda and modern astronomers do.

Dark energy probably is a lambda as far as anyone can tell. Have you still not understood that?

As for inflation, the situation is slightly different - but only slightly. The difference is that the lambda during inflation could not have been a true constant, else inflation would never have ended. But it's very easy to construct consistent, mathematical theories that involve only a very slight extension of general relativity coupled to the standard model of particle physics that behave that way.

The reason is that a lambda term is identical to a constant term in a potential energy functional for a field, and nearly identical to a slowly changing term in a potential energy functional for a field. (I know that means nothing to you and you will ignore it, but it's not directed at you.) Now that we have very good evidence that the expansion is accelerating, we have an additional check on the consistency of that procedure. Coupled to the considerable observational evidence for inflation, it is correctly considered the best model for the evolution of the early universe.

 

[Perpetual Student]

Originally Posted by Perpetual Student

MM:

The above series of posts, that was started by my question about the effects of EM forces in the solar system, is quite interesting.
Everyone agrees (including you) that such effects are immeasurably small on planets and moons. The effects that do exist are due to the sun and diminish with the square of the distance away from the sun so that EM forces are even smaller in interstellar space and infinitesimally small in intergalactic space. In contrast, GR accounts for a negligible effect within the solar system but significant effects on cosmological scales. That reality is contained in the following:

[latex] R_\mu_\nu - \dfrac{1}{2}g_\mu_\nu R + g_\mu_\nu\Lambda= \dfrac{8\pi G}{c^4}T_\mu_\nu [/latex]

which I have asked you how well you understand, but you have not yet responded. Is that a fair assessment as to where we stand?