On Dark Energy.

turbo

It took quite a bit of digging (and I get sidetracked very easily) but here is a very cogent paper from a researcher (Puthoff) taking exactly the same approach I am using to model lensing without resorting to the curved space-time of General Relativity. He substitutes Polarized Vacuum for curved space-time in General Relativity, with some interesting extensions that I had not anticipated.

Outside of a basic understanding of optics, I don't have the math skills to explain my ideas about lensing in ways that are understandable to physicists or mathemeticians, which is probably why Nereid seemed puzzled by my insistence that the GR concept of "gravitational lensing" is inaccurate in light of the quantized structure of space-time envisioned by LQG. You may remember that for some time, I have been exploring whether vacuum energy might be polarized (oriented by local fields):

http://www.physicsforums.com/showthread.php?t=37724
http://www.physicsforums.com/showthread.php?t=28868

After you read Puthoff's paper, you will know why I've been pursuing this. One question still bugging me is this: Can mass create such extreme distortion of the units of space-time that the virtual pairs that define ZPE do not have room to arise (like the small gap between the plates of the Casimir Effect experimental equipment). I may eventually have to reconcile the concept that "space-time" belongs in the Einsteinian GR, and that the fine structure of space-time in a quantum extension of GR will more properly be expressed as vacuum energy.

Puthoff models the space-time distortion caused by mass as polarization of the vacuum field (ZPE) and equates the variable polarization as a change in refractive index. He then explains "gravitational lensing" in terms of the optical properties of the lensing media. That seemed to offend you terribly when I did it, Chronos, judging from the tone of the quote above. I wonder if you think his paper stinks, too? At least, you get math with his "theoretical cow pie".

http://www.arxiv.org/abs/gr-qc/9909037

Nereid

Thanks Garth; this has been troubling me since I first read your SCC paper!

So you pays your money and you places your bets:
1) concordance cosmology (full of non-baryonic dark matter - collisionless, interacts via gravity only)
2) MOND (does wonders with galaxy rotation curves and dwarf galaxies; fails for clusters, doesn't incorporate Relativity)
3) SCC, or 'free-coasting' universes (no such thing as non-baryonic dark matter; not even hints on what form all the dark baryonic matter might be in).

Garth, doesn't it bug you intensely that you haven't got a handle on what form the 'missing' baryonic matter is in? I mean, just about every possibility has been constrained - in many cases quite severely - and the sums keep coming up way short.

Nereid

Well said Chronos! The three papers are quite interesting; as I particularly liked the first, I'm going to paste some text from the abstract here: "Compared with Friedmann models of the universe, the distant SNe are too faint even for a freely coasting, "empty" universe, barring other influences that could dim the events. This result is independent of the absolute calibration of the peak luminosity, which is needed to derive the Hubble constant. Possible noncosmological explanations could be gray dust, with properties that do not change the color of the objects significantly, evolution of the explosions, or deamplification by gravitational lensing. Current indications are that none of these alternatives alone can explain the dimness of the distant SNe.

[...]

However, current lack of understanding of the explosion physics and the radiation transport of SNe Ia encumbers any investigation of evolutionary changes. Any change in the peak luminosity of SNe Ia must be inferred from indirect observations, such as light-curve shape, colors, and spectral evolution. At the moment, many of the distant SNe do not have the required data set for a detailed investigation of these parameters. The near-uniform light-curve and spectral evolution of SNe Ia can be used as accurate cosmic clocks to demonstrate the time dilation as predicted from expanding world models. The test has been performed through both photometry and spectroscopy, and is fully consistent with the predictions. The supernova (SN) results can be reconciled only with cosmological models that provide some form of acceleration. The simplest such models either include the cosmological constant or refer to a decaying particle field ("quintessence")."

One may dislike 'epicycles', but short of saying 'gee, I haven't a clue about what the good observational data are telling us', what alternatives to 'dark energy' and 'dark matter' are there? (at the risk of boring everyone totally senseless, I personally don't think the distant SNe data are good enough yet, nor all potential 'non-cosmological' causes fully understood; I'm glad that Leibundgut at least partially agrees).

I'm also not as relaxed as Chronos seems to be about the freely coasting models and 'primordial abundances'; there's no new physics, so Gehlaut et al, let's have precise predictions on nuclide abundances (not just 'metallicities', nor even 'elemental')!

One small thing: "Standard Model" - I know this is used by particle physics folk to describe QCD, the zoo of particles, the hypothesised Higgs, ... is it also commonly used to describe the [tex]\Lambda[/tex]CDM cosmologies?

Nereid

Wasn't it ever thus? Aren't these folk human too? On top of which, the big institutions now pay marketing folk to write PRs; they have to justify their jobs too!

Best address it by good work, not moaning.Do you have a link to the RAS lecture? AFAIK, the three pillars are nucleosynthesis (primordial nuclide abundance), the Hubble relationship (expanding universe), and the CMBR.It's worth taking the time to look at these in some detail.

First (she said, sounding once again like a broken record), most of the top quality data is in the public domain; anyone can get it and do their own analyses.

Second, I'll issue an open challenge on the 'cosmological observations are all theory dependent, change the theory and those observations change too' claim: while the *papers* reporting the observations may be written with certain theories built into the analyses, can you show that the underlying *data* have such built in? This PF thread, about the CMBR, has a link to a 1999 Tegmark paper on analysing the BOOMERANG, WMAP, and Planck data, to remove foregrounds (it was written before all three even started); unless I misunderstood the paper, the *data* from these three could comprise both the 'cosmological signal' (free of any theory) as well as the 'foregrounds'; how a researcher chooses to analyse the data - wrt a particular cosmological model - is up to her!

The challenge: what (cosmologically relevant) observational data has been collected with 'cosmological theories' built-in?

Nereid

With respect turbo-1, I think it's a little different:
- GR works
- GR predicts the bending of light by mass
- we observe something that looks exactly like what GR predicts (many tests done to support this)
- the mass (amount, distribution) estimated by assuming GR is large, this amount of mass is larger than what we would expect from the M/L ratios of luminous objects (e.g. galaxies).
- However, the 'non-luminous mass' estimated from straight application of GR is ~OOM the 'total mass' estimated from not one but TWO independent sets of observations (X-ray and velocity dispersion).

So the choices are: 1) throw out GR (the only mass that's 'really there' is that we can estimate from the distribution of light); 2) keep GR (the mass that we estimate from the images and GR is much higher than that we infer from the light).Indeed; again, if the only thing were rotational curves, it'd qualify as an epicycle; however, to sound even more like a broken record, the DM estimates that you get from the galaxy rotation curves are consistent with estimates of the amount of DM from independent observations!Hmm, remind me again what a wise woman said about the wisdom of throwing out GR?

Garth

Thank you Neried for some much valued constructive criticism of SCC!

Not really! Though it would be nice to resolve this problem, I don't pretend, or even expect, to be able to solve all the questions at once!

But let me ask you, doesn't it bug you that you haven't got a handle on what form the DM is in? I know there is a whole zoo of possibilities but each seems to have its own problems, just this last week New Scientist reports that neutrinos are now out of the picture. : (NS 4 Sep 04 pg 39 "Weighing the invisible")

As for Bruno's Leibundgut comments "Compared with Friedmann models of the universe, the distant SNe are too faint even for a freely coasting, "empty" universe, barring other influences that could dim the events." He was referring to an empty Friedmann universe, the Freely Coasting universe requires a new gravitational paradigm, it is not empty and so his analysis is not appropriate. "Change the theory and the observations/deductions change too".
May I humbly suggest SCC for your consideration?

The work on nuclide abundances in the freely coasting cosmology is coming along, despite a lack of funds I believe, and one problem is that Deuterium comes out with a low primordial abundance that has to be reconciled by spallation later. But the nuclide abundances of the Standard [tex]\Lambda[/tex]CDM model developed out of about two decades of intense research - give the alternatives a chance!
I am not moaning, just asking questions and seeking possible alternative against which the standard models may be tested, isn't this what good science is all about?
The RAS lecture was given by Prof. J.P. Ostriker (IoA) entited "Concordance Cosmology" on May 14th at the RAS Monthly meeting. It was very good but I couldn't help reflect on the invisibility of those three pillars I mentioned. Of course I agree that your pillars are sound, just that there are other ways of explaining them viz: SCC and the freely coasting universe.

In the Standard model the theory that all our cosmological observations are dependent on is GR! I distinguish between the raw data (red shift, angular size, apparent magnitude etc.) and observation, which is deduced from the data (recession, curvature etc.) For example, the fact that the CMB WMAP data indicate flatness is taken to mean that the cosmological density parameter is unity, but this only applies if the GR cosmological equations hold. They do not in alternative theories such as BD or SCC

I thank you again for a decent discussion and criticism of my ideas - Garth.

turbo

Yes GR works for LOTS of observations, but it seems not to work very well at the galactic scale and it fails utterly at very small scales. Now why does GR fail to predict the behavior of clusters without plugging in dark matter? My hunch is that GR fails to properly model the effects of matter on ZPE (classical space-time in the GR view) and vice-versa, which is why I have been digging up papers on LQG, ZPE etc, and bugging people like you by stating cosmological problems in non-relativistic terms. When the dust clears, I believe we will find that the mysterious "missing mass" is simply ZPE interacting with matter. The ZPE that we observe in the Casimir effect is 120 OOM weaker than predicted by theory, possibly because the virtual pairs that form ZPE are oriented quite randomly. It may be that the potential of the ZPE field is not unlocked until it is polarized (oriented, densified, etc) by the presence of very large masses. The folks at CIPA model both inertial mass and gravitational mass as interactions between matter and the ZPE field. Since I found their site yesterday, I've been devouring papers and articles linked to it.

http://www.calphysics.org/index.html

Nereid, I would not throw out GR, any more than I would throw out the Newtonian model of gravitation. They are both useful. When you have a useful tool you do not throw it away. If you encounter a job where your tool is not appropriate to the task, however, you should realize its limitations, use the tool only where appropriate, and try to develop a better tool for the tough jobs. That one is choice 3), which you did not list. Choice 4) is to establish an extension for GR that keeps it from breaking down at very small scales. I don't hold out much hope for 4), but think 3) is promising.

GR breaks down at very small scales (where ZPE lives) and I believe that this failure is the source of the misapprehension about the "missing mass" on very large scales. If the CIPA folks are right, we do not need dark matter, dark energy, Higgs Bosons, WIMPS, etc. to explain the gravitational behavior of the Universe, simply the interaction of matter with vacuum energy.

If I understand ZPE properly, its energy potential is 120 OOM larger than the observed Casimir Effect, so plenty of energy could be developed from just a small amount of polarization. The reason we don't see ZPE in the macro world is that it is all pervasive and exists at the lowest energy possible. There is no "contrast" in the ground state.

Garth

But shouldn't we see massive curvature from all this energy? Garth

turbo

I stole this directly from the CIPA site:

I haven't discovered how this was derived (in a published paper) yet, but am still searching. CITEbase is addictive and each relevant citation can lead to other interesting paper. For instance, I have been chided for using optical models to explain the "gravitational" refraction of light, and having never been a researcher in physics I meekly assumed that my approach was novel and unconventional enough to earn me status as a crackpot. Thanks to CITEbase, earlier today I ran across this paper, in which the author cites the work of over a dozen physicists who have developed non-relativistic optical models for gravitational refraction over the course of the last 80+ years. This does not mean my optical approach is correct, of course, but If I'm wrong, I've at least got company.

http://citebase.eprints.org/cgi-bin/...2Dph%2F0302273

Nereid

Really?Well, maybe. All we know is that it and QM are mutually inconsistent at those small scales; AFAIK, no one has done any experiments in the relevant regime to actually take a look and see what happens! (of course, thousands would just love to do that, but no one has a spare $trillion or eight)But if you say GR fails, you must also say that the virial theorem fails, and gas equilibrium considerations fail ... and they all fail in the same way!But you don't have to tie yourself in knots about distant galaxy clusters to test these ideas, after all, there's plenty of DM in our own Milky Way halo, and lots of interesting mass concentrations quite local that any ZPE-matter interactions can be tested with.It is a most extraordinary miss, isn't it!

Rothiemurchus

Gravity probe B may yet produce a surprising result that tells us more about dark energy/ dark matter.But if it does not then general relativity will be harder to knock
in future.

turbo

Well, the amount of dark matter that is required to hold clusters together is huge, the amount of dark matter required to cause the flat rotation curves of spiral galaxies is huge, and the distributions of dark matter in both cases must be rather special (put in by hand, with clear intent to fix the failures). This indicates to me that GR is not predictive at very large scales.
Could there ever be enough money, space, or electrical power to construct and operate an accelerator to probe those energies?
I'm not at all familiar with how "gas equilibrium" is used to estimate masses. Do you have a link? As for GR and the virial theorem, they both rely on the classical concept that inertial mass and gravitational mass are intrinsic to matter. The CIPA folks and others are working on the concept that neither gravitational mass nor inertial mass are intrinsic properties of matter, but instead arise out of matter's interaction with quantum fields. Central to this concept is that the interaction is mutual, and matter polarizes (creates differentials in) quantum fields. In matter-rich clusters, where the quantum fields are highly polarized (aligned, densified...), the fields may endow matter with far more inertial and gravitational mass than we might otherwise expect - enough to hold the cluster together without dark matter. If gravity and inertia are endowed on matter through its interaction with quantum fields, we must expect that an increase in field strength will result in an increase of those properties. Ergo, the matter populating extremely dense clusters (with highly polarized quantum fields) will have more inertial mass and more gravitational mass than identical matter in less-dense surroundings. I forgot to mention that it will lens like crazy.
Local won't be easy. The effects of ZPE-matter interactions will be most visible in the domains containing the most mass, thus the interest in galactic clusters. The effects may also be visible where the distribution of matter is such that differences in inertia/mass caused by interaction with a strongly curved ZPE field might give rise to anomolous velocities. MOND, anyone? I've been searching CITEbase for clues that somebody is studying ZPE inertia in light of MOND. Nothing yet.

Correction! I should have searched out Milgrom's papers first of all. He speculates here that MOND could be a modification of inertia due to a vacuum effect. It's an older paper, so he doesn't refer to the EM ZPE work being done by CIPA. MOND would be a perfect experimental test bed for CIPA.
http://citebase.eprints.org/cgi-bin/...tro-ph/9805346
Yes it is. Please read the quote in my last post to Garth above. I lifted it off the CIPA site after wondering about the cosmological effect of SUCH a large energy potential.

Note that CIPA concentrates on the EM Zero-Point Energy field because it shows the most promise for manipulation in terms of Breakthrough Propulsion. NASA is picking up the tab.

Nereid

No earthly accelerator using any technology currently conceivable could begin to probe these regions; the only useful thing to spend the $$ on would be satellite observatories like a super-GLAST, a super-SNAP, a super-LISA, or earthly observatories such as a super-AMANDA or super-LIGO.I seem to recall someone recently talking about epicycles ... as I read these words here, my mind kept flashing 'epicycle! epicycle!' ... I can't imagine why

{maybe marcus can give us a tune, 'you say "tomato", I say "ZPE"; you say "potato", I say "dark matter"'!}

turbo

OK, I can see you just a teensy bit uncomfortable with inertia and gravity arising from masses interaction with ZPE fields. Poke around here a bit, though, and see what you think:

http://www.calphysics.org/index.html

You may view mass-ZPE-interaction as an epicycle. I see it to be just the opposite - an elegant solution to a couple of GR's biggest problems.

It is economical of entities (reduces rather than creates necessary entities) and it is testable. Occam would demand that we give it a shot. Rotation curves of spiral galxies can provide experimental evidence. MOND appears to work, and ZPE field-induced differential inertia may be why. The slick thing is that all the elements needed are already out there - 1) matter in 2) a bound system existing in 3) space-time suffused by 4) quantum fields. No need for obedient, prescient dark matter clumping up in just such densities and distributions to keep our precious GR accurate. Another potential test - can ZPE explain the mass/luminosity ratio of X-ray clusters? MOND has a problem with this class of objects.

I predict that the first researcher to create a testable model of ZPE inertia as the cause of differental rotation in spiral galaxies will have to buy a new dinner jacket and learn a few words of Swedish.

Nereid

I don't particularly like, or dislike, DM, DE, or any other concept; when reading a theoretician's paper I ask "is this consistent with the observational data?". If the 'freely coasting' folk say 'nuclide abundances? no problem!' then I expect to see something a bit more falsifiable than "the same as the lowest metallicities currently observed" (or words to that effect)

Re neutrinos: I have thought for some time that they can't be more than a minor player (unless there's a whole unknown new spectrum of types as yet unobserved).Someone like Pete or DW can comment better than I as to how well SCC fits the honourable tradition of "let's tweak GR a bit, to better test GR itself"maybe, but all that work is there for folk to take and modify; there's little trail-blazing to do.Thanks. I forgot a 'pillar' - large scale structure, per 2dF and SDSS. BTW, I expect that the second year of WMAP data will enable some pretty discriminating tests ... of the concordance model, free coasting, ... but not, maybe, SCC or turbo-1's ZPE ideas maybe, but you can use the data - yourself - to test SCC, surely?

Garth

That is precisely what the "freely coasting" team claim to have done.
As I said in an earlier post apart from having an obvious interest in SCC, what I, and others **, are concerned about is the "over" confidence placed in the standard paradigm. I would have thought alternatives would have been of more interest in the name of good scientific practice. But the key point is that some these alternatives are testable in experiments such as GPB. Even then Kenneth Nordtvedt has said that the GPB experiment was worth doing when it was first planned in the 1960s, but that today the result is a foregone conclusion.

** see http://www.cosmologystatement.org/

turbo

My name is there. I had to sign. As a former chemist (process chemist in pulp and paper mills and later consultant to various corporate entities, including Westvaco, Georgia-Pacific, and Du Pont) and even later as an optician in a large opthalmic practise (avoiding the need to fly all over the country and eat diner food) I have some basic familiarity with the scientific method.

I am not a physicist by training, but my avocation of observational astronomy and astrophotography led me to relate problems in astronomy and cosmology to the fields that I am familiar with, particularly optics. I have for a very long time followed the work of Halton Arp, Geof and Margaret Burbidge and others in the popular press, and as soon as the Internet became available here in the Hinterlands, I followed them there as well. One in-depth correspondence with Mr. Halton "Chip" Arp (arising from a letter I wrote in reference to an article by one of his detractors) gave me an enduring respect for the man. I already knew that he is a disciplined observational astronomer. The correspondence cemented the fact that I was dealing with a real gentleman. It also showed me that I was dealing with a man who understood the significance of proposing paradigm-altering concepts in a field that is firmly committed to nearly 100 years of conventionality. He is quite philosophical about that. A gentleman, as I said.

I have had similar interactions with two equivalent intellects in other fields - Cecil Rhodes who was Professor Emeritus of English Literature at the University of Maine (and a Rhodes Scholar). He tried to ride herd over a bunch of us Engineering students with high SATs, and he actually turned me to the Dark Side of the Force, and was a pivotal force in my switch from Chemical Engineering to English Literature, with a concentration on the Romantic Period. The other man was Erling Skorpen, Dean of Philosophy, who let me into his grad-student and senior-only Meta-ethics course after a "brief" 3-hour "lunchtime" Q&A that I was led to believe would last less than 15 minutes. He had a 3pm class and begged off with a commitment that we would re-engage. I was a sophomore, and had never taken a basic philosophy course. I never had to take one after either, and maintained a double major - in English Lit and Ph. All these men are gentlemen in the truest sense of the word. As the son of a mill-worker living in a very poor town, their treatment of me was greatly appreciated. I felt the same way dealing with Halton Arp.