Mature stars in ancient galaxies

In summary, the paper discusses the discovery of established systems at z ≈ 6, a significant finding considering the young age of the Universe at that time. The existence of "reddening dust" is examined and dismissed, with a focus on classical optics and the role of the quantum vacuum as the transmissive medium. The paper concludes that there must have been starbursts at an earlier epoch which may have helped reionise the early universe. The allowed range of masses for several SFR models are also discussed.
  • #36
Unsurprisingly enough, I agree with ST. The arguments in favor of some amount of CDM [and very likely a huge fraction] are overwhelming. Virtually every other model that relies on black holes, MACHO's, or other baryonic entities has been [in my opinion] been convincingly ruled out. And these are not 'educated guesses', they are supported by cold, hard statistical probabilities that bombard us from many different directions. I don't like injecting unobserved entities into the big picture, but liking it is optional. And betting against the odds on favorite rubs me wrong. I can't bring myself to write it all off as coincidence. On the other hand, I have a sneaking suspicion the truth is even weirder than we imagine. I lean toward the notion DM and DE are manifestations of the same underlying principle. I will even be so bold as to suggest they are the missing entities in the correct theory of quantum gravity.
 
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  • #37
turbo-1 said:
I am in my mid-50s, and am trying to build a retirement fund, so I don't have the time or resources to go back to school and provide mathematical quantification for this model. You'll be able to dismiss me as a crank at for at least the next 10-12 years - tons of fun! I am an amateur astronomer and an ABO -certified optician, and initially started studying the quantum vacuum in order to explore a classical optical model for "gravitational" lensing that does not rely on the concept that massless photons follow geodesics in curved space-time.

Look, turbo, you're a nice guy, probably much nicer than I, but you must have some idea for why I find your theoretical "contributions" inappropriate. It's not just that you can't do math, it's also that you really aren't that knowledgeable about modern astronomy, at least relative to the professionals. We devote our lives to studying these things, so you shouldn't be ashamed of this fact, but you should certainly consider it before trying tell an entire community of scientists that they're misguided. Humility is the key word here. If I were to burst into somebody's office, having no training in their area of expertise, and proceed to tell them that they were doing everything wrong, don't you think that person would have a right to be upset?

Physical science, as performed by the community in which I and others work, demands a certain level of rigor and responsibility if it is to be carried out effectively. Insomuch as this forum is considered to be one in which real science is discussed, I don't think its unreasonable of me to demand that same level of rigor and responsibility from you. The fact that you have no quantitative backing for your theory renders it, in my view, inviable to even make predictions.
 
  • #38
SpaceTiger said:
It's suggesting that a z = 7 reionization yields a UV background that suppresses star formation at z < 7, which is exactly the opposite of what you're trying to show...
Actually what the original paper says is galaxies with stars that formed prior to z ~ 7 have been observed. I'm not trying to show anything except there may be a problem reconciling observation with the standard theory, but you well be right to say "the standard model is pretty safe".
I was assuming a particle source of dark matter (which seems much more probable given the observations), but I can assure you that "bricks" would not be pressurized either.
They would be, before they became "bricks - or whatever".
That requires you to actually find it first! If you concentrate the dark matter into massive objects, then they also become very sparse and the chances of one passing close enought to detect becomes very small. If you're looking for another calculation to do, try calculating the number of dark matter objects that would pass through the solar system in a decade as a function of their mass given the current observational data.
My suggestion is that DM is originally baryonic and now found mainly in intermediate mass BH's (102 - 104 that are the end state of massive PopIII stars in the supposed range (102 - 105) MSolar.

So taking 103 MSolar as a 'typical' value. For rich cluster DM it would take 1012 of 103 MSolar BHs. Typical rich cluster size? 107 parsecs diameter? Volume ~1021 parsecs3 , IMBH density ~ one per ~109 parsecs3, i.e. ~ one per 103 parsecs in ball park numbers.

Is it unreasonable to suggest there is an IMBH every thousand parsecs?
I'll grant you the possibility that your theory fits the data (though I doubt it), but what successful predictions have you made?
That the Pioneer spacecraft should appear to suffer a sunwards acceleration equal to cH, that the Earth should appear to 'spin-up' relative to the orbital period of the moon by H - both of which may already have been observed.
Try telling that to the GRG editorial board, they are pretty sharp - and how!
I look forward to the results.
Likewise - and how!
Garth
 
  • #39
Garth said:
Actually what the original paper says is galaxies with stars that formed prior to z ~ 7 have been observed.

That would be z > 7, an epoch in which the paper says it's easier to form stars.


They would be, before they became "bricks - or whatever".

They can't have become "bricks" after nucleosynthesis because we have tight constraints on the relative density of baryons at that time, so that would be irrelevant for the growth of structure. The only viable "bricks" at this point seem to be PBHs, and those would be pressureless as well.


Is it unreasonable to suggest there is an IMBH every thousand parsecs?

That depends on who you ask, but I'll admit it's a possibility (though only for primordial black holes).


That the Pioneer spacecraft should appear to suffer a sunwards acceleration equal to cH, that the Earth should appear to 'spin-up' relative to the orbital period of the moon by H - both of which may already have been observed.

If you predicted the magnitude of the acceleration of Pioneer, it would give me pause, but otherwise, I would say that's not very impressive. Same with the spin-up of the earth. The standard model (including DM and DE), on the other hand, predicted the shape of the CMB power spectrum to very high precision.
 
  • #40
SpaceTiger said:
If you predicted the magnitude of the acceleration of Pioneer, it would give me pause, but otherwise, I would say that's not very impressive. Same with the spin-up of the earth. The standard model (including DM and DE), on the other hand, predicted the shape of the CMB power spectrum to very high precision.
You'll find it all discussed in my latest published paper, arXived here. A Concordant “Freely Coasting” Cosmology produced by SCC also gives "the location of the primary acoustic peaks in the same range of angles as that given in Standard Cosmology."

Garth
 
  • #41
Garth said:
...gives "the location of the primary acoustic peaks in the same range of angles as that given in Standard Cosmology."

I took a look at the paper you cited for that (Gehaut et al. 2003). First of all, as far as I can tell, this paper was never accepted for publication (please send me a link if this is incorrect). Second of all, they don't claim to show precise concordance with the CMB (as with the standard model), they instead say:

Essential features of CMB anisotropy follow from the above analysis. In
the rest of this article we shall be content with making rough estimates
of CMB anisotropy peak locations to judge whether there is any a-priori
discordance with observations.

I'm not even convinced that the above is correct. In equation 58, they give an expression for a forced and damped harmonic oscillator that's supposed to describe the acoustic fluctuations. Fine, I'll accept that, but this equation alone isn't enough to reproduce the acoustic peaks. One also needs the appropriate initial conditions; that is, the modes must be synchronized by some process. In the standard model, inflation is responsible for this, but you say you don't invoke inflation in your model. How do the modes synchronize?
 
  • #42
SpaceTiger said:
If you predicted the magnitude of the acceleration of Pioneer, it would give me pause
It does -almost, the anomalous acceleration aP = (8.74±1.33)×10−8 cm/s2 is close to the value of 'Hubble acceleration' Ha = cH = 6.69×10−8cm/s2.
This may be explained by a 'clock slip' between ephemeris time and atomic time. Relativity Theory and a Real Pioneer Effect , by Peter Ostermann
Keeping the relativistic laws of motion a non-conventional Pioneer effect would prove an increase of the scale rate of atomic clocks in comparison with planetary ones.
The discrepancy between the observed effect and cH may be easily explained by residual radiation anisotropy and gas leakage by the spacecraft . Such a clock slip is predicted by SCC.
SpaceTiger said:
I took a look at the paper you cited for that (Gehaut et al. 2003). First of all, as far as I can tell, this paper was never accepted for publication (please send me a link if this is incorrect).
The Indian team's work on freely coasting cosmology has only been published on the arXiv; Kolb's original paper "A Coasting Cosmolgy" was published Ap.J. 344.543-550 1989 Sept. 15.
Second of all, they don't claim to show precise concordance with the CMB (as with the standard model), they instead say:
Essential features of CMB anisotropy follow from the above analysis. In the rest of this article we shall be content with making rough estimates of CMB anisotropy peak locations to judge whether there is any a-priori discordance with observations.
I'm not even convinced that the above is correct. In equation 58, they give an expression for a forced and damped harmonic oscillator that's supposed to describe the acoustic fluctuations. Fine, I'll accept that, but this equation alone isn't enough to reproduce the acoustic peaks. One also needs the appropriate initial conditions; that is, the modes must be synchronized by some process. In the standard model, inflation is responsible for this, but you say you don't invoke inflation in your model. How do the modes synchronize?
There is still work to do – resources have not been as forthcoming as for the standard model! The freely coasting CMB temperature anisotropy power spectrum has to be fine tuned by the initial conditions, no more so, however, than the standard model, with its many parameters. The Gehlaut paper finishes by saying:
Finally, we are tempted to mention that a linear coasting cosmology presents itself as a falsifiable model. It is encouraging to observe its concordance ! In standard cosmology, falsifiability has taken on a backstage - one just constrains the values of cosmological parameters subjecting the data to Bayesian statistics. Ideally, one would have been very content with a cosmology based on physics that we have already tested in the laboratory. Clearly, standard cosmology does not pass that test. One needs a mixture of hot and cold dark matter, together with (now) some form of dark energy to act as a cosmological constant, to find any concordance with observations. In other words, one uses observations to parametrize theory in Standard Cosmology.
Linear coasting presents a very distinguishable cosmology. Recombination occurs at age ~ 107 years as opposed to ~105 years in standard cosmology. The Hubble scale at decoupling is thus two orders of magnitude greater in linear coasting. This fact, coupled with the absence of any horizon, could well have falsified linear coasting. Any concordance with observations is therefore very significant. The model comes with its characteristic predictions.
Thus linear coasting has the potential of relegating the need for any form of dark matter or dark energy (or for that matter, any physics not already tested in the laboratory) to the physics archives where they enjoy the same status as ether and phlogiston. The message this article is to convey is that a universe that is born and evolves as a curvature dominated model has a tremendous concordance and there are sufficient grounds to explore models that support such a coasting.
SCC does support such a coasting and it is being independently tested at this moment; to be falsified or otherwise; we wait and see.

Garth
 
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  • #43
This discussion is fascinating to watch, but I feel I need to step in here. I think SpaceTiger has explained the mainstream model's response to the OP. Garth is bringing the discussion into SCC, for which we have other dedicated threads. And turbo-1 is touching upon an alternative theory (for which I look forward to seeing in the Independent Research forum). Plus, some of the comments are getting a bit more personal. So, I'm closing this one up. But if you 3 really would like to keep hashing it out here, let me know via PM. You also have the option of continuing 1-on-1 via PMs. Thanks.
 
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