Lambda-CDM theory - Woo or not?

[Michael Mozina]

Einstein developed GR before Hubble's discoveries and, with the inclusion of lambda, GR was quite consistent with a steady state universe.

The problem however is that once he realized the universe was not static, he realized that the introduction of a constant was unnecessary and probably not related to gravity in the first place. He called the introduction of this constant his "greatest blunder". They've now resurrected a new and improved "blunder" theory, not GR. GR is an elegant piece of physics the way Einstein taught it, without constants, without the need for push-me-pull-you stuff that has nothing to do with the *attractive* force of "gravity". Now they've even added *acceleration* to this process. In fairness however, I've seen a pretty good paper that attempts to do away with "Dark energy" with the introduction of ordinary EM fields. It does however require "inflation" get the party started, but at least it takes *some* of the metaphysics out of their theory. They'd probably never embrace the concept however because then they would have to admit that there is a persistent, all pervasive EM field in space and they'd have to embrace huge parts of EU theory.

If you go over to Bad Astronomy (such an appropriate name), you'll notice one cannot even discuss *any* elements of EU/PC theory beyond 90 days. It's like a microcosmic example of the problem on a larger scale. They operate like a cult, not a group of "scientists" in search of truth. It's fine to yack on forever about BS like inflation and dark evil energy, but heaven forbid one should mention EM fields in space.

 

[Michael Mozina]

No you don't. If you did you wouldn't be arguing about whether spacetime could expand or not.

I'm not. I accept that objects in motion stay in motion, and I have no problem with "spacetime' expansion. It's only when you start trying to resurrect a version of blunder theory and try to claim "space" expands that I start to balk. I'd like to see you demonstrate that form of "expansion" in an empirical way before you start pointing at the sky with a magic math formula.

 

[sol invictus]

Einstein developed GR before Hubble's discoveries and, with the inclusion of lambda, GR was quite consistent with a steady state universe.

Actually that's really not true. That solution is unstable - it exists, but it's analogous to a solution in which an infinitely sharp pencil is perfectly balanced on its point. The slightest perturbation, and it falls one way or the other (which in this case means it either begins to contract or expand exponentially fast).

Anyway, the point is that all but a set of measure zero of solutions to Einstein's equations for a homogeneous and isotropic universe are either expanding or contracting. So either you accept that as the generic state of things, or you reject GR.

 

[sol invictus]

The problem however is that once he realized the universe was not static, he realized that the introduction of a constant was unnecessary and probably not related to gravity in the first place. He called the introduction of this constant his "greatest blunder". They've now resurrected a new and improved "blunder" theory, not GR. GR is an elegant piece of physics the way Einstein taught it, without constants, without the need for push-me-pull-you stuff that has nothing to do with the *attractive* force of "gravity". Now they've even added *acceleration* to this process. In fairness however, I've seen a pretty good paper that attempts to do away with "Dark energy" with the introduction of ordinary EM fields. It does however require "inflation" get the party started, but at least it takes *some* of the metaphysics out of their theory. They'd probably never embrace the concept however because then they would have to admit that there is a persistent, all pervasive EM field in space and they'd have to embrace huge parts of EU theory.

If you go over to Bad Astronomy (such an appropriate name), you'll notice one cannot even discuss *any* elements of EU/PC theory beyond 90 days. It's like a microcosmic example of the problem on a larger scale. They operate like a cult, not a group of "scientists" in search of truth. It's fine to yack on forever about BS like inflation and dark evil energy, but heaven forbid one should mention EM fields in space.

Ah, that evil cult of scientists again.

Have you taken your meds?

I'm not. I accept that objects in motion stay in motion, and I have no problem with "spacetime' expansion. It's only when you start trying to resurrect a version of blunder theory and try to claim "space" expands that I start to balk. I'd like to see you demonstrate that form of "expansion" in an empirical way before you start pointing at the sky with a magic math formula.

You shouldn't use terms you don't understand, Michael. "spacetime expansion" and "space expanding" are exactly the same thing.

When physicists talk about "expanding spacetimes", what they mean is a geometry in which the space expands as a function of time. And all cosmological solutions to Einstein's equations have that property - except one unstable exception, and that one requires the cosmological constant you seem to hate so much.

 

[Michael Mozina]

Thanks for the feedback.

It may be a while before I get to post the next installment, if only because I'm putting my time into trying to understand the MM view of cosmology, as a science.

What exactly is your motive in trying to understand *my* views of cosmology? We're talking about *mainstream* beliefs about cosmology in this thread. My personal beliefs are actually irrelevant to the legitimacy (or lack thereof) of Lambda-Gumby theory. You should be able to make your case, with or without understanding my personal opinions on cosmology. Why all the effort aimed at me? Can't actually empirically demonstrate your case perhaps, so you're attempting to draw attention away from that fact by attacking me? These sound eerily similar to creationist tactics in a debate. They never make their own case via the scientific method. Can't you empirically demonstrate the validity of Lambda-(IcantDemonstrate96PercentOfThisNonsense) theory?

 

[sol invictus]

What exactly is your motive in trying to understand *my* views of cosmology? We're talking about *mainstream* beliefs about cosmology in this thread. My personal beliefs are actually irrelevant to the legitimacy (or lack thereof) of Lambda-Gumby theory. You should be able to make your case, with or without understanding my personal opinions on cosmology. Why all the effort aimed at me? Can't actually empirically demonstrate your case perhaps, so you're attempting to draw attention away from that fact by attacking me? These sound eerily similar to creationist tactics in a debate. They never make their own case via the scientific method. Can't you empirically demonstrate the validity of Lambda-(IcantDemonstrate96PercentOfThisNonsense) theory?

The problem, Michael, is that that has already been done. Lambda-CDM does an very good job accounting for the empirical data (of which there is a huge quantity) - a far better job than any other theory in the history of the subject, and a far better job than any alternative.

You're the only one that doesn't think that - so I think DRD is just trying to figure out why. This is about you, not physics.

 

[Michael Mozina]

Ah, that evil cult of scientists again.

Have you taken your meds?

Gee, what a great debate tactic. You're really convincing me now....

You shouldn't use terms you don't understand, Michael. "spacetime expansion" and "space expanding" are exactly the same thing.

BS. Objects in motion may indeed stay in motion, but they will never achieve "superluminal" expansion because objects of mass cannot move faster than light. Your gumby theory does superluminal magic tricks.

When physicists talk about "expanding spacetimes", what they mean is a geometry in which the space expands as a function of time.

Oh, so I'm obligated to include magic now in your expansion mythos because you play word games? Sorry. They are not the same concept. "Expansion' of objects is not the same as expansion of "space". You *can* empirically demonstrate the expansion of objects, not the expansion of space. I don't care about your word games.

And all cosmological solutions to Einstein's equations have that property - except one unstable exception, and that one requires the cosmological constant you seem to hate so much.

And yet now you're stuffing acceleration forces in there and so many fudge factors it doesn't even resemble GR or gravity, it's an entire cosmology theory built on 4% physics and 96% fudge factor.

 

[DeiRenDopa]

What exactly is your motive in trying to understand *my* views of cosmology? We're talking about *mainstream* beliefs about cosmology in this thread. My personal beliefs are actually irrelevant to the legitimacy (or lack thereof) of Lambda-Gumby theory. You should be able to make your case, with or without understanding my personal opinions on cosmology. Why all the effort aimed at me? Can't actually empirically demonstrate your case perhaps, so you're attempting to draw attention away from that fact by attacking me? These sound eerily similar to creationist tactics in a debate. They never make their own case via the scientific method. Can't you empirically demonstrate the validity of Lambda-(IcantDemonstrate96PercentOfThisNonsense) theory?

Fair question Michael.

As I said earlier in this thread (bold added):

I'd like to see where we're up to, wrt answering the question this thread asks.

First, the question - and thread - appears in the JREF Forum's Science, Mathematics, Medicine, and Technology section, so I guess it's OK to assume "woo" means "woo in the context of "Science, Mathematics, Medicine, and/or Technology". Further, since "Lambda-CDM theory" doesn't have anything to do with Medicine, we can refine the scope. Then, although there are certainly Mathematics and Technology aspects to "Lambda-CDM theory" they are secondary*.

So the question becomes "is "Lambda-CDM theory" scientific woo or not?".

Well, to answer that question, we need to have a common understanding of what "scientific woo" is, don't we?

Of course, we could always ask the site owners or admins or moderators to clarify for us, but ahead of doing that, can we take a stab at working out an answer?

One such answer might be along the lines of "that which is published in relevant peer-reviewed journals and presented at relevant conferences", where "relevant" is understood to mean something like "to do with cosmology".

If so, then "Lambda-CDM theory" is certainly not scientific woo; case closed.

But perhaps a somewhat different definition of 'scientific woo' might be called for, something that deals with what's written in the OP, about 'evidence', 'scrutiny', 'falsification', 'verifiability', and so on?

If so, then "Lambda-CDM theory" is certainly not scientific woo, as was made quite clear in the first page of posts in this thread ... it has been intensely scrutinised, there is tonnes of evidence to support it (and essentially none that doesn't), it is quintessentially falsifiable and verifiable, and so on.

Now I think it's fair to say that MM, the OP, is of the (strong) opinion that "Lambda-CDM theory" is, in fact, woo.

Why?

Clearly not because of reasons of falsifiability, verifiability, evidence, scrutiny etc ... if those were the kinds of reasons, then he'd've provided a link to a paper such as this: Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation (link is to the astro-ph preprint; some formatting is lost):

(Abridged) The WMAP 5-year data strongly limit deviations from the minimal LCDM model. We constrain the physics of inflation via Gaussianity, adiabaticity, the power spectrum shape, gravitational waves, and spatial curvature. We also constrain the properties of dark energy, parity-violation, and neutrinos. We detect no convincing deviations from the minimal model. The parameters of the LCDM model, derived from WMAP combined with the distance measurements from the Type Ia supernovae (SN) and the Baryon Acoustic Oscillations (BAO), are: Omega_b=0.0456+-0.0015, Omega_c=0.228+-0.013, Omega_Lambda=0.726+-0.015, H_0=70.5+-1.3 km/s/Mpc, n_s=0.960+-0.013, tau=0.084+-0.016, and sigma_8=0.812+-0.026. With WMAP+BAO+SN, we find the tensor-to-scalar ratio r<0.22 (95% CL), and n_s>1 is disfavored regardless of r. We obtain tight, simultaneous limits on the (constant) equation of state of dark energy and curvature. We provide a set of "WMAP distance priors," to test a variety of dark energy models. We test a time-dependent w with a present value constrained as -0.33<1+w_0<0.21 (95% CL). Temperature and matter fluctuations obey the adiabatic relation to within 8.9% and 2.1% for the axion and curvaton-type dark matter, respectively. The TE and EB spectra constrain cosmic parity-violation. We find the limit on the total mass of neutrinos, sum(m_nu)<0.67 eV (95% CL), which is free from the uncertainty in the normalization of the large-scale structure data. The effective number of neutrino species is constrained as N_{eff} = 4.4+-1.5 (68%), consistent with the standard value of 3.04. Finally, limits on primordial non-Gaussianity are -9<f_{NL}^{local}<111 and -151<f_{NL}^{equil}<253 (95% CL) for the local and equilateral models, respectively.

So what's going on?

Here's my working hypothesis: MM has a very different view of what modern cosmology, as a science, is than almost everyone else who has posted to this thread. If that's the case, I'd like to take this thread in somewhat of a different direction and focus on what MM's view of modern cosmology, as a science, is. In particular, I'd like to examine the extent to which it is internally consistent and the evidence there is that it employs critical thinking.

* though perhaps it's worth taking a look at these aspects later

Since then it's been clearly established that you do, indeed, have "a very different view of what modern cosmology, as a science, is than almost everyone else who has posted to this thread"

So the main thing that is still being discussed, in this thread, is how and why you, MM, regard modern cosmology (or at least LCDM models) as scientific woo.

Now there are many ways to go about answering that question (or set of questions); I've chosen a particular approach that involves first understanding the scope of what you regard as cosmology (and you've been most forthcoming on that topic, thanks), then determining what criteria you use to assess acceptability, within that scope.

I'm sorry to read that you think I'm "attacking" you; may I assure you that I'm not, and ask that you point me to the posts where you think I was (so I can modify my future posts so as to avoid giving you this perception)?

 

[DeiRenDopa]

GAH! Always the to be continued when it gets interesting!

My first feedback would be to have it in a separate thread instead of a post buried in a thread, easier to deal with and reference.

Second, I hope you do spend some good time with the implications of GR, something I think I don't fully get. During one thread I saw the term co-moving coordinates and it took me a bit to really get what that means, but I think that actually hurts me rather than helps me.

It was a thread about galaxies moving away faster than the speed of light, and the co-moving coordinates is only one way to view it.. the other way was that galaxies further away have time moving more slowly so are younger (as we would appear younger to them), but that's something I don't think I fully appreciate the implications of.

Anyway, look forward to the continuation.

Some resources, in case you (or Skwinty, or ...) haven't come across them already.

Ned Wright's Cosmology Tutorial (almost no math)

Talk Origins' Evidence for the Big Bang (no math at all, but may be too broad for what you're interested in)

Living Reviews in Relativity (a very great deal of math, but the introduction sections are uniformly good)

Within that, the latest version of Clifford Will's The Confrontation between General Relativity and Experiment (much too technical in most places, but gives a very good idea of just how extensively GR has been tested).

For places where you can get answers to your specific questions, there's the BAUT Q&A section (MM has mentioned BAUT several times, and there's a connection with JREF too - Phil Plait is co-owner of BAUT)

Physics Forums is also a good place to hang out, especially as their mission includes "homework help"! However, you may find some of the old hands are a bit jaded by repeatedly answering common questions. Depending on what you're interested in, you may start with the Cosmology section, and hope that you catch marcus' eye.

 

[sol invictus]

BS. Objects in motion may indeed stay in motion, but they will never achieve "superluminal" expansion because objects of mass cannot move faster than light. Your gumby theory does superluminal magic tricks.

What are you talking about? I didn't say anything about "superluminal expansion", whatever you think that is.

Oh, so I'm obligated to include magic now in your expansion mythos because you play word games? Sorry. They are not the same concept. "Expansion' of objects is not the same as expansion of "space". You *can* empirically demonstrate the expansion of objects, not the expansion of space. I don't care about your word games.

Expansion of objects? What objects - what are you talking about? You tried to draw a distinction between "spacetime expansion" and expanding space, which is absurd.

You have no idea what you're talking about, and as usual when called on it you respond with non-sequitors. Just like humber.

And yet now you're stuffing acceleration forces in there and so many fudge factors it doesn't even resemble GR or gravity, it's an entire cosmology theory built on 4% physics and 96% fudge factor.

For the third time, what are you talking about? I said all solutions (with that one exception). Do you dispute that? If so, please provide us with one example of a homogeneous and isotropic cosmology in which the space isn't either expanding or contracting.

Oh wait, I forgot - you can't, because you don't have a clue what you're saying.

 

[Skwinty]

Thanks DeiRenDopa,
Will read some more of your recommended links.
Always good to hear your calm and logical debate.

Unlike Sol Invectus, spelling intentional.
Origin:
1400–50; late ME < LL invectivus abusive, equiv. to L invect(us) (ptp. of invehi to attack with words,

It is apparent to me after reading articles like http://arxiv.org/abs/0707.0380v1 that Michael is not alone in his opinions about expanding space.

Extract from above article

Expanding Space: the Root of all Evil?

Martin Rees & Steven Weinberg (1993) state
...how is it possible for space, which is utterly
empty, to expand? How can nothing
expand? The answer is: space does
not expand. Cosmologists sometimes talk
about expanding space, but they should
know better.

3 Conclusion
Despite (and perhaps in part because of) its ubiquity,
the concept of expanding space has often been articulated
poorly and formulated in contradictory ways.
That addressing this issue is important must be placed
beyond doubt, as the phrase ‘expansion of space’ is
in such a wide use—from technical papers, through to
textbooks and material intended for school students or
the general public—that it is no exaggeration to label
it the most prominent feature of Big Bang cosmologies.
In this paper, we have shown how a consistent description
of cosmological dynamics emerges from the idea
that the expansion of space is neither more nor less
than the increase over time of the distance between
observers at rest with respect to the cosmic fluid.
This description of the cosmic expansion should be
considered a teaching and conceptual aid, rather than
a physical theory with an attendant clutch of physical
predictions. We have demonstrated the power of this
pragmatic conceptualisation in guiding understanding
of the universe, particularly in avoiding the traps into
which we can be lead without rigorous recourse to general
relativity.
The utility of approximation in handling the less
tractable properties of cosmologies is undiminished,
but the understanding of physical systems therein will
be hampered wherever full covariance is absent. All
observational properties—whether derived in the dynamically
evolving FRW metric or the Minkowski-like
conformal representation—must be the same, independent
of the choice of co-ordinates. As general relativity
approaches its one-hundredth birthday, this is a lesson
that all cosmologists should learn

 

[sol invictus]

I'd rather be correct than polite (although I acknowledge that both is the ideal). This is supposed to be an educational forum, and I won't tolerate quacks posting wrong physics and pretending it makes sense, any more than anyone else here tolerates homeopaths or creationists. Honest mistakes or misunderstands are one thing; repeated falsehoods, refusal to engage with contradictory evidence, failure to support assertions, and arrogant vitriol unsupported by even basic knowledge are another.

If you don't like it, don't read it.

It is apparent to me after reading articles like http://arxiv.org/abs/0707.0380v1 that Michael is not alone in his opinions about expanding space.

Umm - I think you need to go back and re-read that article. Their conclusion is the opposite of how you make it sound - namely they conclude that there is no other concept that can replace that of the expansion of space in cosmology. And they're right, although I'll agree the concept is sometimes misunderstood.

Their abstract is enough to make it clear:

While it remains the staple of virtually all cosmological teaching, the concept of expanding space in explaining the increasing separation of galaxies has recently come under fire as a dangerous idea whose application leads to the development of confusion and the establishment of misconceptions. In this paper, we develop a notion of expanding space that is completely valid as a framework for the description of the evolution of the universe and whose application allows an intuitive understanding of the influence of universal expansion. We also demonstrate how arguments against the concept in general have failed thus far, as they imbue expanding space with physical properties not consistent with the expectations of general relativity.

I'm curious about the Rees/Weinberg quote, but I'd need to see it in context. Certainly they are correct that if there is nothing in the space, there is no unambiguous sense in which it is expanding. I already made that point in this thread in the context of scalar condensates - if that's the only form of energy present, one can "slice" those spaces to make them look expanding, contracting, or static - it's a choice of coordinates.

 

[sol invictus]

dp

 

[Tubbythin]

I kept trying to post this earlier but couldn't...

BS. Objects in motion may indeed stay in motion, but they will never achieve "superluminal" expansion because objects of mass cannot move faster than light. Your gumby theory does superluminal magic tricks.

Nope. Relativity tells us that objects cannot move through space faster than the speed of light. It says nothing about a fundamental limit of on the rate of space-time expansion. We've been through this already.

Oh, so I'm obligated to include magic now in your expansion mythos because you play word games? Sorry. They are not the same concept. "Expansion' of objects is not the same as expansion of "space". You *can* empirically demonstrate the expansion of objects, not the expansion of space. I don't care about your word games.

Expanding (and contradicting) spacetime was described in the 1920's with the Friedmann equation, a set of solutions to GR. (FWIW it was also endorsed by Einstein). You reject the Friedmann equation you reject GR. Its as simple as that.

And yet now you're stuffing acceleration forces in there and so many fudge factors it doesn't even resemble GR or gravity, it's an entire cosmology theory built on 4% physics and 96% fudge factor.

Nope. The cosmological constant is included in the Friedmann equation (though it produces logical solutions whether or not it is non-zero).

 

[Tubbythin]

I'm not. I accept that objects in motion stay in motion, and I have no problem with "spacetime' expansion. It's only when you start trying to resurrect a version of blunder theory and try to claim "space" expands that I start to balk. I'd like to see you demonstrate that form of "expansion" in an empirical way before you start pointing at the sky with a magic math formula.

*Shakes head in sheer amazement at the above comment.*

 

[Tubbythin]

These sound eerily similar to creationist tactics in a debate. They never make their own case via the scientific method. Can't you empirically demonstrate the validity of Lambda-(IcantDemonstrate96PercentOfThisNonsense) theory?

Creationist tactics like appeal to a long list of names. Complete misrepresentation of the topic at hand. Demanding the theory in question explains stuff it was never intended to explain or be tested in such a way as to falsify the theory if the test was succesful. Regular shifting of goal posts. Complete refusal to subject their own pet theory to the standard of proof they demand of others.
Oh wait, these were all tactics used by you.

 

[Perpetual Student]

I've heard that before, but it typically it was done as a handwave rather than a real argument. Perhaps you could explain the Oblers paradox issue in your own words?

Rather than use my own words, here is a quick and easy summary:

http://math.ucr.edu/home/baez/physics/Relativity/GR/olbers.html

I haven't personally invested a whole lot of time on the supernova data, although Ari has definitely done some work on it.

What does he say about it? The observed time dilation of distant supernovae would appear to rule out any "tired light" or EM theory.

I'm not sure what you figure violates the laws of thermodynamics, but if you can explain what you mean, I'll do my best to respond to it.

Well, I'm on thin ice here, but I'll try. The second law of thermodynamics states that the entropy of a system which is not in equilibrium will tend to increase over time, approaching a maximum value (at equilibrium). So, that would also have to apply to the total universe. If the universe did not have a beginning, it would have attained total equilibrium by now.

 

[temporalillusion]

Some resources, in case you (or Skwinty, or ...) haven't come across them already.

Some new ones in there, thanks!!

 

[DeiRenDopa]

Thanks DeiRenDopa,
Will read some more of your recommended links.
Always good to hear your calm and logical debate.

Um, er, you're welcome

Unlike Sol Invectus, spelling intentional.
Origin:
1400–50; late ME < LL invectivus abusive, equiv. to L invect(us) (ptp. of invehi to attack with words,

[...]

Sol i has already responded to your post, but I thought I'd try to sketch what the broader canvas looks like ...

IMPORTANT CAVEAT/INTRO: in what follows I am making no value judgment, am not intentionally attacking anyone, am not intentionally 'dissing' anything or anyone by implication, etc.

Michael Mozina has a number of papers published, in peer-reviewed journals (I think he is a co-author in all, and may not be the leading author in any, if that's important in any way). The topics of those papers are all within the part of science called physics, and most (all?) within astrophysics. This fact was, I think, either strongly implied or directly mentioned, very early on in the history of MM's posting in this part of the JREF Forum; in any case, it is the work of but a minute or two to ascertain (unless there are more than one "Michael Mozina"s!).

Within the community in which sol i works (so I guess), and those of many others who've responded to MM's posts in this forum (e.g Tim Thompson), a well-understood, long-standing, completely acceptable convention is to assume that authors of published papers are intimately familiar with at least the physics essential to the content of the paper(s) of which they are authors. Further, the default assumption, by such people, is that such authors are assumed to have a good working knowledge of the other parts of physics that they explicitly cite.

When, in the course of debate and discussion, it becomes clear that this is not, in fact, the case, a fairly typical (but by no means universal) response is a 'robust' (shall we say) attack ... in essence 'you came across as having at least a strong post-grad understanding of {insert field here}, but you've made a blooper equivalent to 'the queen of England is Mao Zedong', so either fess up, admit the blooper, or I'll rip into you like Motl did to Lisi'.

The other thing to bear in mind is that the physics departments of major universities receive something like an average of one unsolicited crackpot 'theory' a week in the (snail) mail (and maybe more via email).

With this (all too brief) sketch as background, if you were in sol i's shoes, how do you think you'd've replied to MM's posts?

If you were in MM's shoes, how do you think you'd've replied to sol i's posts?

I hope this is of some help to you, to understand better the general context of at least some of the discussion in this thread.

 

[DeiRenDopa]

Some new ones in there, thanks!!

No worries.

I thought a bit about your first post (in response to mine), and I agree with you ... there really should be a separate thread on 'what does 'space expands' mean, in modern cosmology?' (or similar).

Does any reader know if someone - a moderator or admin - can copy or split out the posts on that topic (in this thread), to form a new thread? If so, how does one go about asking for that to happen?

The paper that Skwinty provided a link to is good, but it's (obviously!) addressed to an audience that is already very familiar with GR, so I imagine it may be quite a struggle for some readers to wade through. In any case, it makes several points that will form the next part of my answer to him (her?) on this, namely a look at the relationship between interpretations of (extremely) successful theories in modern physics and 'observables' ('pedagogies', if you will).

Oh, and have you come across the Lineweaver and Davis papers, and Scientific American article, that Francis et al. reference? If not, I recommend them too!