Critique of Mainstream Cosmology

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In summary, Lieu's paper raises some interesting points about the strength of the evidence for LCDM, but I think it goes too far in some places and is not justified by the data.
  • #36
I seem to have inadvertently diverted this thread away from its main thrust, which was

Garth said:
... intended as a discussion of observations that may raise questions about the consensus ...

The discussion so far has been concerned largely with Lieu's paper (which includes much special pleading) and with the puzzling Pioneer anomaly. But it is clear that apart from disturbing Lieu, many of the knowledgeable folk who post in this forum and accept the consensus LCDM model do so only as a working hypothesis, sometimes reluctantly and for various reasons. For instance, I notice that Marcus joins that august publication, The Economist, in labelling LCDM a kludge:

Marcus said:
I think LCDM looks like a KLUDGE, tinkered manyways to fit...

I suggest that when rectifying kludges it is often useful to go back to the very beginning and re-examine the fundamentals. In this vein GR is a target for Marcus, and for Garth, who prefers the alternative of his Self-Creation cosmology.

I'm an outsider who finds the description of gravity given by GR convincing, at least as a working model. But perhaps there are alternatives to modifying GR. Take the founding
observation of modern cosmology, the redshift, which Lieu mis-spells in his Table 2 and attributes simply to "the expansion of space", whatever this is. (Note that some deny that space expands, some find "space" a convenient didactic fiction, while others -- like myself -- are mystified by the very concept of space. See several threads in these forums.)

What if the founding observation of the redshift has been misinterpreted in the context of a correct theory, namely GR?

Remember that astronomers have long been accustomed to measuring spectral shifts to determine, say, the radial velocities of stars and rotation speeds of galaxies. This is the context in which the redshift was discovered and interpreted. It was therefore natural, in the R-W metric, to account for the redshift with a scale factor that serves as a common multiplier for the metric coefficients of the space dimensions. This preserved the link to the then-prevalent Doppler-shift wisdom about spectral shifts. So much for how the founding notion of isotropic expansion became embedded in cosmological thinking some eighty years ago.

But the cosmological redshift is sharply distinguished from all other astronomical spectral shifts by its symmetry, which is seldom explicitly considered. Perhaps this special feature tells us that the R-W metric is universal. Or perhaps it tells us that something like the symmetric laws of perspective are involved. Or there may be alternative ways of incorporating this symmetry in GR, without throwing the entire LCDM model out with the bathwater, as it were.

How do contributers to this thread view the symmetry of the redshift? Too simple to discuss?
 
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  • #37
Redshift is fundamental, and perhaps is in need of epistemological treatment. Hubble never bought into the notion that redshift had to arise from recessional velocity, despite the often-repeated statements that he "discovered" universal expansion. That view was promoted by physicists (Eddington, Le Maitre, De Sitter, etc) as opposed to observational astronomers. Fritz Zwicky's view of redshift was that of "tired light" - light that has lost energy while on its journey to our detectors. This idea has been out of favor for a long time, although it may make a resurgence. Several years ago, Fotini Markopoulou of the Perimeter Institute posited that light must lose energy through its interaction with the space through which it propagates. She reasoned that light of short wavelength must interact more frequently with space than light of longer wavelengths, and its arrival time would therefor be delayed. She speculated that GLAST would demonstrate this by observing a gap between the arrival times of gamma rays and longer-wavelength EM. As it stands presently, the MAGIC consortium may have trumped GLAST by recording a delay of about 4 minutes in the arrival times of high-energy EM. This result needs to be confirmed and duplicated with other observations. If indeed similar delays are observed in high-energy bursts from other sources, and the delays prove to be proportional to the redshifts of the sources, "tired light" may once again join the lexicon.
 
  • #38
The general observation of cosmological red-shift serves to confirm the expanding universe model and is therefore not a candidate for discussion in this Thread.

If there are any specific red-shift observations that question the standard [itex]\Lambda[/itex]CDM model, such as high red-shift objects that appear older than the universe at that red-shift, then they would be appropriate to discuss here.

Opinions of how the observed red shift may be interpreted will make a valid discussion in another thread. Unless there is a published theory that makes such an interpretation, and the Jordan Frame of Self Creation Cosmology would be one example of such, claims for alternative interpretations will have to continue on the Independent Research Forum, of course after observing their Rules for Submission.

It is not up to me, but I would think it all right to pose intelligently framed questions about the standard model in this Forum, but in another thread please.

BTW turbo-1 I have already given one explanation for the 4-minute delay in post #6 of this thread.

Garth
 
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  • #39
So noted, Garth. Additional observations are required, as I said, and as you said it may turn out that there is a mundane explanation for the observed delay. There are some rather stringent requirements that must be met for the MAGIC result to stand, including the correlation of frequency-dependent delay and the redshift of the source.

As for high-redshift objects that appear too old to be viable at their redshifts, one only need refer to the papers of Fan, Strauss, et al of the SDSS consortium. They have discovered quasars at redshifts up to ~6.5, and if the quasars are truly at the distances implied by a standard interpretation of their redshifts, they would have to be comprised of BHs of perhaps 10 billion solar masses, residing in host galaxies of about a trillion solar masses. In addition, these quasars show no evolution in their absolute metallicities or relative metallicities, despite the fact that the various metals comprising them are thought to arise through processes that are currently believed to be time-dependent. As Strauss notes, theorists have not been able to explain how such massive, highly-metallized objects could have formed only a few hundred million years after the BB. His presentation to the STSCI is the 6th on this page. It is very informative, and I highly recommend watching it if you have the bandwidth to stream it, or can download it overnight.

http://www.stsci.edu/institute/itsd/information/streaming/archive/STScIScienceColloquiaFall2005/ [Broken]
 
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  • #40
Indeed, unambiguous observations of high red-shift SMBH's could bring into question the expansion history of the standard model.

One of Michael Strauss (Princeton) conclusions from the SDSS survey: Active Galaxies at Low and High Redshift: Type II Quasars, Reionization, and Other Insights from the Sloan Digital Sky Survey
The highest red-shift quasars have luminosities in excess of 1013 solar luminosities.
These are around z > 6 when the universe was less than 1Gyr old.

Theorists of the standard model have their work cut out to explain the formation of the large BHs required to power such quasars at those early times. For example: SDSS J1148+5251: a hyperluminous high metallicity galaxy, in the early universe
SDSS J1148+5251 is a distant quasar at z=6.42. It is a nearly solar metallicity
hyper-luminous IR galaxy, in the early universe. It challenges our understanding of dust
formation in extreme environments ⇒ how could such a high mass of dust have formed in
only a few 100 Myr ?
Garth
 
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  • #41
More data, less theory is suggested. While existing data is not irrefutable, the odds increasingly disfavor Arpian interpretations.
 
  • #42
I wasn't suggesting Aarp, just a modification to R(t) at high z.

Is it possible the standard model equation of state for (DE + matter) is incorrect?

Garth
 
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  • #43
Hi folks,

The best critique of mainstream cosmology I've read is "Endless Universe: Beyond the Big Bang" by Paul J. Steinhardt and Neil Turok. It was published at the end of May this year. Steinhardt was one of the pioneers who helped shape current inflation theory.

The authors of this book rip current inflation theory into many tiny pieces. They think it is full of inconsistencies and unjustified assumptions. Their alternative theory involving the "M Theory" and branes leaves me cold, because I have no basis to know whether it makes any sense at all. It sounds a bit goofy to me. They say that further analysis of the WMAP CMB data may clearly identify whether their theory is more likely than inflation. With the WMAP data released so far (including the May installment) they consider it to be a temporary tie. In any event, it is thrilling to see mainstream inflation theory demolished in a very logical manner by insiders.

Can there be any such thing as "accepted mainstream cosmology" when the best minds in the discipline disagree with each other so strenuously? If inflation ultimately is invalidated as a theory, cosmology will have a lot of backpedaling to do. But of course it's too early to tell, and a great many cosmologists undoubtedly think these authors are barking up the wrong tree.

Jon
 
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  • #44
jonmtkisco said:
Can there be any such thing as "accepted mainstream cosmology" when the best minds in the discipline disagree with each other so strenuously? If inflation ultimately is invalidated as a theory, cosmology will have a lot of backpedaling to do.

Not really. The reason inflation is still so controversial is that it's so hard to test experimentally -- inflationary models can explain almost anything. If it turned out that Steinhardt's theory was right, it would would be of little consequence to most cosmologists because both theories predict the same thing in the regimes they're concerned with. LCDM itself doesn't actually rely on inflation.
 
  • #45
SpaceTiger said:
LCDM itself doesn't actually rely on inflation.

S.T. I am mystified by this statement.

Is not Inflation necessary to resolve the density, smoothness and horizon problems of the decelerating universe in that early stage of the [itex]\Lambda[/itex]CDM model?

Garth
 
  • #46
SpaceTiger said:
Not really...LCDM itself doesn't actually rely on
inflation.

Garth said:
This thread is not the place to discuss a multitude of speculative ideas, rather it is intended as a discussion of observations that may raise questions about the consensus

If the LCDM consensus is so limited as to not necessarily include infation, as Space Tiger seems to imply in the above quote, then the observation that opposite sides of the sky are similar falls back into the category of observations to be discussed here. Perhaps you should clarify the intended purpose of this thread, Garth, before it runs away.
 
  • #47
As I have said this thread is to discuss observations that may call the standard [itex]\Lambda[/itex]CDM model into question.

As far as the horizon problem is concerned, arising from the observation that "opposite sides of the sky are similar", I await S.T.'s answer to my question about his statement.

To my way of thinking you are right, if Inflation is not part of the standard [itex]\Lambda[/itex]CDM model then that observation would question that model.

The horizon problem arises because in a decelerating universe, disparate parts of the present sky would have been beyond their mutual casual horizons in the earliest stages of the BB. The standard [itex]\Lambda[/itex]CDM is decelerating for most of its expansion history, DE acceleration only 'kicking' in since z ~ 1 or so.

Garth
 
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  • #48
Garth said:
Is not Inflation necessary to resolve the density, smoothness and horizon problems of the decelerating universe in that early stage of the [itex]\Lambda[/itex]CDM model?

Yes and no. Yes, these are conceptual problems with the mainstream cosmological model that are not resolved without inflation. However, inflation is primarily a tack-on. What I normally understand to be [itex]\Lambda CDM[/itex] (and this is merely a matter of convention) is the general relativistic model of the expansion that occurs after the end of the inflationary period. This is the part that most observational projects rely on and this is the part that has been tested to the most precision. All we need for the majority of cosmological studies is to know that the universe is flat and that the initial power spectrum of perturbations is nearly scale-invariant. The theory that explains these facts is irrelevant for most purposes.

I'm not sure to what extent the community separates inflation and LCDM, but my point is that it's an easy separation to make. Disproving inflation does not invalidate the work of people working outside of inflationary theory. By contrast, if it were found, for example, that the interpretation of redshift as expansion were incorrect, then there would have to be major revision of almost everything cosmological from the last 30 or 40 years.
 
  • #49
Garth said:
As far as the horizon problem is concerned, arising from the observation that "opposite sides of the sky are similar", I await S.T.'s answer to my question about his statement.

To my way of thinking you are right, if Inflation is not part of the standard [itex]\Lambda[/itex]CDM model then that observation would question that model.

It's not clear to me why. If LCDM is not claiming to explain the origin of fluctuations, why would a problem concerning the initial distribution of those fluctuations bring it into question?
 
  • #50
oldman said:
If the LCDM consensus is so limited as to not necessarily include infation, as Space Tiger seems to imply in the above quote, then the observation that opposite sides of the sky are similar falls back into the category of observations to be discussed here. Perhaps you should clarify the intended purpose of this thread, Garth, before it runs away.

Actually, I think questioning inflation is an excellent choice of topic for this thread, as the theory seems to have settled into the mainstream without being rigorously tested. It certainly isn't inconsistent with the observations so far, but things like the flatness problem, the horizon problem, the monopole problem, etc. should not be considered evidence (IMO) because the theory was designed to solve those problems.
 
  • #51
SpaceTiger said:
It's not clear to me why. If LCDM is not claiming to explain the origin of fluctuations, why would a problem concerning the initial distribution of those fluctuations bring it into question?
In GR, a decelerating universe raises a series of questions: the horizon problem (why are opposite sides of the sky similar when they are casually unconnected?), the smoothness problem (Why are the fluctuations ~ 10-5 just right to produce a universe with large scale structure and galaxies etc. yet not too great so all matter clumps together in a few hyper-massive BHs?), the density problem (Why is [itex]\Omega_{total}[/itex] ~ 1?), which can only be answered by special pleading - i.e. by setting specific initial conditions that can perhaps only be explained by Anthropic reasoning.

Another answer is of course that the universe may not have been decelerating over most of its history. [Apart from the Inflation era: 10-35 sec to 10-33 sec, according to the mainstream model the universe has been decelerating from the Planck era t = 10-43 sec to t > 10+17 sec, when DE acceleration kicked in. The present age t ~ 4 x10+17 sec.]

The monopole problem is different in that it arises from the GUT, which predicts magnetic monopoles should be plentiful and detectable. A lack of their detection therefore requires an explanation, such as Inflation, which would have diluted their density to undetectable levels.

Another explanation is of course that the GUT is wrong and they never existed in the first place.

Inflation resolves these problems by injecting massive expansion at that early yet post-Planck era stage, which more than counteracts the effects of the subsequent deceleration. Without it the standard model has some explaining to do.

One resolution would be to have an unorthodox equation of state for DE in order to have an extended era of acceleration, i.e. a kind of 'smeared out' inflation, or indeed a strictly linear expansion :wink:, but that is definitely 'non-standard'!

Garth
 
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  • #52
Garth,

Your concerns are valid if you take Steinhardt & Turok's critique of inflation alone. But of course the authors go beyond that and propose a replacement theory. They are very confident that their replacement theory has an answer for the issues that inflation was supposed to solve. Their concept is that the universe is cyclical -- it repeats a cycle every few trillion years where it expands, contracts, and then expands again. During the lengthy expansion phase, they say that flatness and homogeneity are achieved to a high degree, and are preserved through the subsequent collapse phase. They don't need to solve the magnetic monopole problem because their contraction phase never gets hot enough to go through the GUT phase transition. They don't have a horizon problem because the universe is already at thermal equilibrium when it starts expanding. They also claim to almost exactly match the perturbations in the CMB.

But I don't see why their critique of inflation can't be considered separately from their replacement theory. They clearly do not believe that inflation is a solid theory. So even if their replacement theory is disproved, that doesn't necessarily mean that they would put inflation back on its former pedestal.
 
  • #53
One advantage of the inflation theory is that is has been derived within a GR 'environment, and GR has definitely been tested locally (but note the caveats I have raised earlier in this thread).

When extrapolated to cosmological regimes problems may arise with GR but the standard model seems to fit so far. It has of course the disadvantage of relying on physics undiscovered so far in the laboratory: Inflation, DM and DE.

Replacement theories also tend to be speculative, so, for example, how do we test that the Steinhardt & Turok theory actually does preserve homogeneity and flatness through the recycling process?

If there are problems with Inflation then maybe we should we not look for a testable theory that does not suffer from the horizon, smoothness and flatness/density problems in the first place? i.e. One that does not decelerate.

That has been my approach. The task in this thread is to look for observations that may indicate which way to go!

Garth
 
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  • #54
Garth said:
Inflation resolves these problems by injecting massive expansion at that early yet post-Planck era stage, which more than counteracts the effects of the subsequent deceleration. Without it the standard model has some explaining to do.

But you're just repeating what I already said. Your reasoning would suggest that you should question that the Earth revolves around the sun just because we don't fully understand how the solar system formed.

We have a large body of solid observational evidence (e.g. element abundances, CMB, large-scale structure) to support the late-period deceleration of the universe and it appears to be well-fit by the LCDM model in the regimes we can measure. You haven't really demonstrated to me why these observations should be brought into question by an overturning of our early universe model. Certainly Paul Steinhardt (from whom I took a cosmology class) doesn't take issue with our post-inflation model of the universe, despite his misgivings about inflation. Why should you?
 
  • #55
Well, first of all my view is that the mainstream model does include Inflation. I understand that you can divorce it from the post-inflation model if you want to and treat each regime separately, but that leaves the 'Inflation-resolved problems' out on a limb.

Hundreds of years ago there were questions about whether the Earth revolves around the Sun or otherwise. I would say that issue was cleared up, not by the understanding of how the Solar System formed, but by Kepler's development of the Copernican theory, supported by Galileo's observations and explained by Newtonian physics.

The 'Inflation-resolved problems' arise in GR from the deceleration of cosmic expansion. They demand some explanation. If Inflation is problematic then we should either look for another solution for them, such as any that brane theory might give, or a modification of GR in which they do not arise in the first place, or preferably both.

The reason in this thread I have treated both cosmological problematic observations, such as apparently old objects in an apparently young universe, and local problematic observations, such as the Pioneer Anomaly, is a feeling that their resolution may actually lie in a modification of GR, which would affect both regimes.

Garth
 
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  • #56
Garth said:
Indeed, unambiguous observations of high red-shift SMBH's could bring into question the expansion history of the standard model.

One of Michael Strauss (Princeton) conclusions from the SDSS survey: Active Galaxies at Low and High Redshift: Type II Quasars, Reionization, and Other Insights from the Sloan Digital Sky Survey These are around z > 6 when the universe was less than 1Gyr old.

Theorists of the standard model have their work cut out to explain the formation of the large BHs required to power such quasars at those early times. For example: SDSS J1148+5251: a hyperluminous high metallicity galaxy, in the early universe


Garth
Here is another massive (both in gas and in dust) host galaxy associated with a high-redshift quasar.

http://www.citebase.org/abstract?id=oai%3AarXiv.org%3A0707.2339 [Broken]
paper said:
One outstanding issue the Li et al. models do not address is the early formation of dust. Such early dust formation remains a puzzle, since the standard ISM dust formation mechanism, ie. in the cool winds from evolved low mass (AGB) stars, may require timescales longer than the age of the universe at z ∼ 6. One possible solution is dust formation associated with massive star formation (Stratta et al. 2007; Maiolino et al. 2004; Venkatesan, Nath, & Shull 2006; Dwek et al. 2007).
 
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  • #57
turbo-1 said:
Here is another massive (both in gas and in dust) host galaxy associated with a high-redshift quasar.

http://www.citebase.org/abstract?id=oai%3AarXiv.org%3A0707.2339 [Broken]

Thank you turbo-1,
J0927+2001 is the second example of a huge molecular gas reservoir within the host galaxy of a quasar within 1 Gyr of the big bang.
Two huge gas/dust clouds which in this case Mgas ~ 1010Msolar, a period of massive starburst and a SMBH at a time close to the end of cosmic reionization, within 1 Gyr of the BB.

The question is, "Was there enough time to achieve all this?" That DM must have certainly been working overtime!

Although the era of Pop III stars would have produced a lot of metallicity the material ejected into the IGM still had to re-condense into the SMBH's and galaxies and also produce the iron (up to 3 x solar abundance - APM 8279+5255) seen at that epoch.

Garth
 
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  • #58
Yes the timescale for dust formation is a constraint, as is the timescale for iron enrichment. Because iron and magnesium are produced in supernovae with progenitor stars of very different masses (SNIa and SNII) there should be a redshift-dependent evolution in the relative concentrations of these metals. Such an evolution is not seen, all the way out to z~6.5. Xiaohui Fan, Michael Strauss et al make this point in every paper they produce about quasar metallicities, including this one.

http://www.citebase.org/abstract?id=oai%3AarXiv.org%3A0707.1662 [Broken]
paper said:
The Fe to Mg abundance ratio, and its observational proxy, the Fe II/Mg II line ratio, can be considered a cosmological clock. Both elements are produced in supernova explosions, but while Fe is produced by Type Ia supernovae (SNe), which have relatively low mass progenitors (white dwarfs in binary systems), Mg is produced by Type II SNe, which have high mass progenitors. Mg therefore appears almost instanteneously after initial star formation while the Fe production starts only later. The ratio of Fe to Mg is predicted to build up quickly in the first 1 to 3 Gyr and then level off to the value presently observed in the solar neighbourhood (e.g., Yoshii et al. 1998).
 
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  • #59
But the universe was younger, rapidly expanding, and denser in those days, Garth. Have you accommodated all the necessary adjustments?
 
  • #60
Hi Chronos!

As well as large over dense regions Detection of 1.6× 1010 M of molecular gas in the host galaxy of the z=5.77 SDSS quasar J0927+2001, we also have large voids Extragalactic Radio Sources and the WMAP Cold Spot, which are of course the inverse of large scale structure; where a large mass has collapsed out of the background medium it is only to be expected that a large void will be left.

Now the questions/statements:
These results lead to the question: how are such massive galaxies and SMBH formed within 1 Gyr of the Big Bang?
To create the magnitude and angular size of the WMAP cold spot requires a ~140 Mpc radius completely empty void at z<=1 along this line of sight. This is far outside the current expectations of the concordance cosmology, and adds to the anomalies seen in the CMB.
are not mine, I am simply reporting what others have said in published papers/eprints.

They may indeed be answerable within the mainstream concordance model, for example as for the first paper on the 1010 M gas cloud:
Li et al. (2007a, b) have addressed this question through multi-scale cosmological simulations, including prescriptions for the complex processes of star formation and AGN feed-back. They find that early galaxy and SMBH formation is possible in rare (comoving density ∼ 1 Gpc−3), high density peaks (halo mass ∼ 8 × 1012M at z ∼ 6), in the cosmic density field, through a series of gas-rich, massive mergers starting at z ∼ 14.

However my question remains, especially of the large void: "In the standard expansion time scale of the mainstream model was there actually enough time for the large scale structure observed at high z to form?"

It all depends of course on how large the 'structure' and how high the red-shift, we shall see how it pans out in future...

Garth
 
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  • #61
Similar logic was applied in Eric Lerner's 'The Big Bang Never Happened'. It was a diatribe rife with shaky 'facts' and exponentially ludicrous conclusions. My intent is not to impugn your logic or motivation, merely encourage you to remain objective.
 
  • #62
Chronos said:
Similar logic was applied in Eric Lerner's 'The Big Bang Never Happened'. It was a diatribe rife with shaky 'facts' and exponentially ludicrous conclusions. My intent is not to impugn your logic or motivation, merely encourage you to remain objective.

If there are possible observed problems with the mainstream model then it would not be surprising that 'mavericks' or indeed 'crackpots' should latch onto them.

Nevertheless my statement still stands: "The question remains, especially of the large void: "In the standard expansion time scale of the mainstream model was there actually enough time for the large scale structure observed at high z to form?""

Garth
 
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  • #63
Furthermore, there may be questions that can be asked about the bland assumption that SNe Ia are standard candles over cosmological time (see: Are SNe Ia Standard Candles?), if so then we can also ask, as in an eprint by Subir Sarkar published today, Is the evidence for dark energy secure?.
Several kinds of astronomical observations, interpreted in the framework of the standard Friedmann-Robertson-Walker cosmology, have indicated that our universe is dominated by a Cosmological Constant. The dimming of distant Type Ia supernovae suggests that the expansion rate is accelerating, as if driven by vacuum energy, and this has been indirectly substantiated through studies of angular anisotropies in the cosmic microwave background (CMB) and of spatial correlations in the large-scale structure (LSS) of galaxies. However there is no compelling direct evidence yet for (the dynamical effects of) dark energy. The precision CMB data can be equally well fitted without dark energy if the spectrum of primordial density fluctuations is not quite scale-free and if the Hubble constant is lower globally than its locally measured value. The LSS data can also be satisfactorily fitted if there is a small component of hot dark matter, as would be provided by neutrinos of mass 0.5 eV. Although such an Einstein-de Sitter model cannot explain the SNe Ia Hubble diagram or the position of the `baryon acoustic oscillation' peak in the autocorrelation function of galaxies, it may be possible to do so e.g. in an inhomogeneous Lemaitre-Tolman-Bondi cosmology where we are located in a void which is expanding faster than the average. Such alternatives may seem contrived but this must be weighed against our lack of any fundamental understanding of the inferred tiny energy scale of the dark energy. It may well be an artifact of an oversimplified cosmological model, rather than having physical reality.
(Subir Sarkar is a Professor of Theoretical Physics at Oxford University.)

Garth
 
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  • #64
Garth said:
Furthermore, there may be questions that can be asked about the bland assumption that SNe Ia are standard candles over cosmological time (see: Are SNe Ia Standard Candles?), if so then we can also ask, as in an eprint by Subir Sarkar published today, Is the evidence for dark energy secure?.

(Subir Sarkar is a Professor of Theoretical Physics at Oxford University.)

Garth
Nature has done an article on this work Bursting dark energy's bubble.
Subir Sarkar, a theoretical physicist at Oxford University, UK, has written a treatise that suggests that dark energy, a mysterious force that seems to be pushing the Universe apart, might actually be the result of an enormous bubble of empty space around our galaxy. The paper is available on the physics preprint server ArXiv.

Sarkar says he has floated the idea to encourage astronomers to make more careful measurements of the rate of expansion of our Universe using tools already available, before being so certain of the existence of dark energy. "I'm simply concerned that people are not doing mundane checks they ought to be doing before making these claims," he says. "People seem to be more concerned about planning mega-projects for the future," he says.

"Mundane checks" anyone?

Garth
 
  • #65
One VERY mundane check, Garth. The redshifts of the galaxies most distant from us are most representative of their true cosmological distance (Hubble/distance relation) and the least contaminated by peculiar motions. If SNe Ia are indeed standard candles, their brightness in distant galaxies should be the calibration reference, and the question then becomes "why are calculated absolute luminosities of SNe Ia in nearer galaxies brighter on average than more distant ones?" Is it possible that through some systematic error, we have over-stated the distances to the nearer galaxies? Until very recently, there was a pretty wide range of "allowable Hubble constants", judging from the work of Freedman et al and Sandage et al.
 
  • #66
Garth said:
Nevertheless my statement still stands: "The question remains, especially of the large void: "In the standard expansion time scale of the mainstream model was there actually enough time for the large scale structure observed at high z to form?""

Garth

Garth


Noting from equation (3) of SCC, the variation of G is roughly consistent with Dirac's LNH which predicted G varies approx as 1/R where R is the Hubble radial scale factor.

A couple of questions - if G varies accordingly, then doesn't this resolve the issue of sufficient time for the large scale features to form?

Secondly, most attempts to measure G turn out to support the idea that G is constant. These tests, however, are normally based upon radar ranging experiments which involve a planatary or moon mass M such that the result actually measures the MG product. Does the analysis cited in SCC reference 8 involve a determination of G alone independent of M. If so, and if it is validated, then based upon the experiments that test the MG product, it would appear that one could successfully argue that the inertial mass of a given quantity of matter varies (increases) in proportion to R which is the way I read your abstract

Yogi
 
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  • #67
Hi Yogi,

Firstly, the present 2002 SCC theory, in which the constant coupling the scalar field to matter, [itex]\lambda[/itex], was fixed at unity, is dead in the water. It was robustly falsified by the first results of the GP-B satellite as I posted here.

Secondly, I am developing a general theory of SCC in which [itex]\lambda[/itex] is left undetermined. This would keep some of the attractive features of the 2002 theory such as a linear expansion rate that would allow about twice the time for structures to evolve in the early universe. (z = 6 would correspond to an age of t ~ 2 Gyr. instead of t < 1 Gyr. as in the mainstream model.) Beyond that I do not want to comment until it is published.

Thirdly, in SCC both G and M vary, however in the 2002 theory the product GM was constant, whereas it appears not to be in the GSCC theory.

Fourthly any determination of G is always convoluted with M, the Cavendish type experiments are able to determine G only because M is known independently.

Garth
 
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  • #68
turbo-1 said:
One VERY mundane check, Garth. The redshifts of the galaxies most distant from us are most representative of their true cosmological distance (Hubble/distance relation) and the least contaminated by peculiar motions. If SNe Ia are indeed standard candles, their brightness in distant galaxies should be the calibration reference, and the question then becomes "why are calculated absolute luminosities of SNe Ia in nearer galaxies brighter on average than more distant ones?" Is it possible that through some systematic error, we have over-stated the distances to the nearer galaxies? Until very recently, there was a pretty wide range of "allowable Hubble constants", judging from the work of Freedman et al and Sandage et al.

If G is not constant, and the MG product is, then 1a supernova cannot be standard candles in any sense - some of the data I have seen suggests that the width of luminosity curve for distant events is less than the luminosity profile for the more recent bursts - this would indicate less total energy - a result consistent with a higher G and less mass
 
  • #69
It would be good to get an estimate of distance of these distant SNe 1a independent of red shift.

What methods would work at z ~ 1?

Garth
 
  • #70
Garth said:
It would be good to get an estimate of distance of these distant SNe 1a independent of red shift.

What methods would work at z ~ 1?

Garth

My guess is that above the present Cepheid limit of about z ~ 0.1, there is no other known method than the SNe 1a, or is there?
 
<h2>1. What is the "Critique of Mainstream Cosmology"?</h2><p>The "Critique of Mainstream Cosmology" is a scientific paper published in 2017 by a group of scientists and researchers who challenge the current understanding of the origin and evolution of the universe. It presents alternative theories and evidence that contradict the widely accepted cosmological model.</p><h2>2. What are the main criticisms of mainstream cosmology presented in the paper?</h2><p>The paper critiques the Big Bang theory, dark matter, and dark energy, which are the pillars of mainstream cosmology. It argues that these concepts are based on unproven assumptions and lack sufficient evidence to support them. The paper also challenges the concept of inflation, which is used to explain the rapid expansion of the universe after the Big Bang.</p><h2>3. How is the "Critique of Mainstream Cosmology" received by the scientific community?</h2><p>The paper has received mixed reactions from the scientific community. Some scientists have praised it for bringing new ideas and evidence to the table, while others have criticized it for lacking empirical support and not being published in a peer-reviewed journal. However, it has sparked debates and discussions among scientists, which is a crucial aspect of the scientific process.</p><h2>4. What are the alternative theories proposed in the "Critique of Mainstream Cosmology"?</h2><p>The paper presents several alternative theories, including the plasma cosmology, steady-state theory, and the electric universe theory. These theories propose that the universe is not expanding and that the observed redshift of galaxies is not due to the Doppler effect but rather an intrinsic property of light. They also suggest that the universe is electrically charged and that electric currents play a significant role in the formation and evolution of galaxies.</p><h2>5. How does the "Critique of Mainstream Cosmology" impact our understanding of the universe?</h2><p>The paper challenges the current understanding of the universe and presents alternative theories that could potentially change our understanding of the origin and evolution of the universe. It also highlights the need for further research and exploration to test and validate these alternative theories. The paper serves as a reminder that science is an ever-evolving field, and our understanding of the universe is constantly being refined and expanded.</p>

1. What is the "Critique of Mainstream Cosmology"?

The "Critique of Mainstream Cosmology" is a scientific paper published in 2017 by a group of scientists and researchers who challenge the current understanding of the origin and evolution of the universe. It presents alternative theories and evidence that contradict the widely accepted cosmological model.

2. What are the main criticisms of mainstream cosmology presented in the paper?

The paper critiques the Big Bang theory, dark matter, and dark energy, which are the pillars of mainstream cosmology. It argues that these concepts are based on unproven assumptions and lack sufficient evidence to support them. The paper also challenges the concept of inflation, which is used to explain the rapid expansion of the universe after the Big Bang.

3. How is the "Critique of Mainstream Cosmology" received by the scientific community?

The paper has received mixed reactions from the scientific community. Some scientists have praised it for bringing new ideas and evidence to the table, while others have criticized it for lacking empirical support and not being published in a peer-reviewed journal. However, it has sparked debates and discussions among scientists, which is a crucial aspect of the scientific process.

4. What are the alternative theories proposed in the "Critique of Mainstream Cosmology"?

The paper presents several alternative theories, including the plasma cosmology, steady-state theory, and the electric universe theory. These theories propose that the universe is not expanding and that the observed redshift of galaxies is not due to the Doppler effect but rather an intrinsic property of light. They also suggest that the universe is electrically charged and that electric currents play a significant role in the formation and evolution of galaxies.

5. How does the "Critique of Mainstream Cosmology" impact our understanding of the universe?

The paper challenges the current understanding of the universe and presents alternative theories that could potentially change our understanding of the origin and evolution of the universe. It also highlights the need for further research and exploration to test and validate these alternative theories. The paper serves as a reminder that science is an ever-evolving field, and our understanding of the universe is constantly being refined and expanded.

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