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View Full Version : Dark energy - misconception of the relationship between redshift and scalefactor.



john hunter
2007-Aug-10, 09:30 AM
Dear ATM,

In www.rescalingsymmetry.com there is an updated proposal that there has been a serious and long standing misunderstanding of the relationship between redshift and scale factor of the universe.

On just four short web pages, support is given. There is a very good match to both the supernovae data, and WMAP, which currently gives omega(matter) of about 0.26 and an equation of state parameter of -1 http://arxiv.org/abs/astro-ph/0603449 and http://map.gsfc.nasa.gov/m_mm.html

From rescaling a value for omega of 0.25 and equation of state parameter of -1 is predicted.

These matches occcur naturally from a simple symmetry principle without the need for dark energy.

John Hunter.

tusenfem
2007-Aug-10, 10:22 AM
AHhhh noooo, uniform scaling, everything gets bigger in the universe!

john hunter
2007-Aug-10, 04:25 PM
Dear tusenfem,

Yes, why not! Maybe there is now some evidence for it, from WMAP and supernovae data.

The alternative is a period of inflation + dark energy, with a variable and unexplained deceleration parameter q(z). http://arxiv.org/abs/astro-ph/0512586

John Hunter.

Peter Wilson
2007-Aug-10, 06:49 PM
Dear ATM,
...These matches occcur naturally from a simple symmetry principle without the need for dark energy.
That's what I've been saying!

:rolleyes:

John Mendenhall
2007-Aug-10, 06:56 PM
Dear tusenfem,

Yes, why not! Maybe there is now some evidence for it, from WMAP and supernovae data.

The alternative is a period of inflation + dark energy, with a variable and unexplained deceleration parameter q(z). http://arxiv.org/abs/astro-ph/0512586

John Hunter.

Why? Local expansion in gravitationally bound systems does not happen in GR. The site cited seems more interested in taking the integral out of the formula than anything else. I notice that there are a lot of people on ATM and elsewhere whose math stops at algebra, and are nevertheless trying to redo SR and GR. If you want to propose changes to SR and GR, you had better have the math down. And it ain't easy. There are good reasons why only a few solutions are known for the Einstein equations. Ten simultaneous tensors, lots of differential equations, mucho topology - it goes on and on, for something that can be expressed so simply. The speed of light as measured by any observer in their reference frame is c, and all observers see the same physical laws. Try going through the Wiki articles and actually doing the math.

This idea simply proposes a band-aid on the expansion. It introduces an unneeded and arbitrary complication. On more physical grounds, I suspect that such expansion would be detectable in planetary orbits. And maybe G.

tusenfem
2007-Aug-10, 07:29 PM
If everything gets bigger, thus also our rulers, how are we supposed to notice it then? There is no way of doing that, even though it might look nice with a drawn person-telescope-starts-ruler. Looking at things from the "god perspective" is nice, but it is not one we can have.

On the second page Planck's constant is made variable over time. I seem to remember that a paper (and indeed here it is (http://adsabs.harvard.edu/abs/1976ApJ...209..330S)) that discusses that there is observational evidence that Planck's constant has not changed over time. The abstract reads:



An attempt has been made to observe whether old photons have the same relation between wavelength and energy as young photons. No detectable difference was found, using quasars with redshift up to z = 1.6 as sources. Assuming that the speed of light is cosmologically constant, the observations give an upper limit for a hypothetical variation of Planck's constant of less than 1 part in 1 trillion per year in a reasonable cosmological model.


And what is the reason that H = 0.5 H0? That is suddenly introduced on page 2 and used on page 3, but as far as I see no explanation. Methinks this is taken just to make the answer of Omega = 0.25 in the end.

John Mendenhall
2007-Aug-10, 08:35 PM
And what is the reason that H = 0.5 H0? That is suddenly introduced on page 2 and used on page 3, but as far as I see no explanation. Methinks this is taken just to make the answer of Omega = 0.25 in the end.



Hey, you gotta do what you gotta do to make your theory work.

john hunter
2007-Aug-11, 10:09 AM
Thanks Peter,

Dear John and tusenfem,

Both of you question why H is half of H(0). But it is clearly explained if you look at the first two pages of the four on www.rescalingsymmetry.com .
It's not just 'put in' to make things match WMAP. It occurs naturally and simply. Work on this idea has progressed. For a while a value of 1/3 was derived for omega, from Newtonian considerations. Now there is a solution from Einsteins equations of General Relativity.

tusenfem, the point of rescaling symmetry is that it is undetectable, so you can't prove that it isn't happening. There would be no measureable change in Plancks constant or any other physical constant locally. The paper you mentioned has made the false assumption that the redshift of light is from an expansion of space and not a rescaling.

John, too many people get bogged down in maths and 'can't see the wood for the trees'. However the solution to Einsteins equations on page 3 is from General Relativity. You said that there aren't many, well here is one which matches the data, and has k=0 and lambda = 0 (nice and simple).

John Hunter.

Michael Noonan
2007-Aug-11, 11:22 AM
Why do we assume that an initial "fluid" making its own space spreads faster than the speed of the energy limit?

Surely that only happens in any fluid only if it is added to an existing fluid.

Simple experiment:-
1. pour oil into a pan.
2. note it is resisted while spreading
3. add some more oil
4. note it spreads faster by spreading the original oil

Why does the perfect fluid of the big bang act so differently to any other fluid?

tusenfem
2007-Aug-11, 12:45 PM
Both of you question why H is half of H(0). But it is clearly explained if you look at the first two pages of the four on www.rescalingsymmetry.com .
It's not just 'put in' to make things match WMAP. It occurs naturally and simply. Work on this idea has progressed. For a while a value of 1/3 was derived for omega, from Newtonian considerations. Now there is a solution from Einsteins equations of General Relativity.

tusenfem, the point of rescaling symmetry is that it is undetectable, so you can't prove that it isn't happening. There would be no measureable change in Plancks constant or any other physical constant locally. The paper you mentioned has made the false assumption that the redshift of light is from an expansion of space and not a rescaling.


I have taken a somanieth look at the pages, and I see no explanation why H is half H0 it is just posited on the first page. They (you?) just chose it for whatever reason, and most likely because half the value gives you the right answer. Please explain to us here why it should be 0.5.

rescaling is undetectable, yes, so we cannot prove it is not happening, just like you cannot prove it is happening, by just looking around us. so if it is not detectable, why would planck's constant change and all other values of natural constants? that is something that we would observe, I think. If everything scales, and expands, this means that protons and neutrons grow, and electrons too and the (taking for simplicity the Bohr model) the orbits of the electrons, and thus the electric field must change, i.e. a combination of e and eps(0), which would change current density etc. etc. etc. All these effects would most definitely show stuff in the spectra from far away galaxy.

You cannot just take one little thing and change it, without thinking about the whole of physics.

john hunter
2007-Aug-12, 10:53 AM
Dear tusenfem,

According to rescaling theory every physical constant rescales according to the number of length dimensions in it.

Plancks consant has metres squared i.e. 2, for its length dimension so h=h(0)exp(2Ht)

That is why the rescaling constant is half of Hubbles constant. The theory then matches normal redshift observations...but it also leads to a natural match of the supernovae magnitudes against redshift, with no dark energy and a constant value of H. What is new with this post is that it has been found that it also gives omega(matter) of 0.25, and equation of state parameter of -1...with no extra assumptions or fiddles. Straight from Einsteins equations of General Relativity.

The 2 factor has been in for about 2 years (in BAUT), if you look through previous posts, even when WMAP gave a value of about 0.3. The factor 2 has been there before any BAUT posts, since 1995.

John Hunter.

Nereid
2007-Aug-12, 10:12 PM
How does the apparent size of a standard ruler (orthogonal to the line of sight) vary, with distance?

How does alpha (the fine structure constant) vary, in this john hunter idea?

How about the other coupling constants (http://math.ucr.edu/home/baez/constants.html) (not mass)?

I didn't see where, in these four pages, you showed your idea was consistent with GR; would you mind saying a few words about the extent to which it is?

Specifically, in what ways are gravitational lenses different, in a john hunter universe, than in a GR universe?

In this john hunter idea, what is (are) the cause(s) of the observed angular power spectrum in the CMB?

How did the apparent asymmetry between matter and anti-matter arise, in this john hunter cosmology idea?

How does this idea address the observed relative primordial abundance of light nuclides?

(That'll do for now; later I might ask about the ISW and BAO).

john hunter
2007-Aug-13, 11:31 AM
Dear Nereid,



How did the apparent asymmetry between matter and anti-matter arise, in this john hunter cosmology idea?


Can we start with this, as it seems most interesting.

In particle physics there are some symmetries e.g. CPT, i.e if we reverse time and parity and charge, of reactions which can occur, then the reversed one can occur too.

What might be the case is that if we reverse time, change matter for antimatter and the rescaling constant H for -H. Then the universe would look the same. CHT symmetry.

It would be an antimatter universe instead of a matter one, but we wouldn't know the difference. It always appears asymmetric, but the deeper underlying laws of nature would be symmetric.

In the model G = 3H^2/8*pi*rho, but because H is squared it can be changed for -H.

John Hunter.

john hunter
2007-Aug-14, 09:26 AM
Dear Nereid,

On some other of the questions:

The fine structure constant is dimensionless, and so would not vary in this model, either locally, or by distant observations.

The ruler one isn't clear to me. If we assume a flat universe, which is what rescaling model suggests...then the angle subtended by the ruler (from us) would half if the 'distance' doubles.

Presumably your asking, because if we look back in time then the ruler should be shorter (or the earth grown bigger) in the time taken for the light to travel. Lots of rulers put together to make a circle which circles the earth must still appear connected, i.e. each ruler couldn't appear to have less angle from earth. So the answer is to do with the definition of 'distance'. You might have to clarify that question.

About the abundancies of nuclei.

There is a problem with the amount of Lithium 6 and 7 produced according to standard Big Bang Nucleosynthesis. Another part of rescaling theory, which we've discussed before, suggests a reduction in G for regions of matter with mass/radius ratio approaching c^2/G. So multiple 'Bangs' might help with this Lithium problem. www.gravity.uk.com (ammended)

John Hunter.

Nereid
2007-Aug-14, 05:38 PM
[snip]

The ruler one isn't clear to me. If we assume a flat universe, which is what rescaling model suggests...then the angle subtended by the ruler (from us) would half if the 'distance' doubles.

Presumably your asking, because if we look back in time then the ruler should be shorter (or the earth grown bigger) in the time taken for the light to travel. Lots of rulers put together to make a circle which circles the earth must still appear connected, i.e. each ruler couldn't appear to have less angle from earth. So the answer is to do with the definition of 'distance'. You might have to clarify that question.

[snip]Indeed, I wrote too fast.

What I am interested in is how various notions of distance, in non-Newtonian universes, differ ... comparing a standard (concordance model) cosmology with the john hunter one presented in this thread.

My question referred to the angular diameter measure of distance, but I'm also interested in the luminosity and comoving ones.

This page (http://www.chronon.org/applets/cosmological_distances.html) may be a good place to start; it has links to a couple of websites with much more detailed background (inc formulae).

john hunter
2007-Aug-15, 08:53 AM
Dear Nereid,

It might be best to try and derive d=2(1+z)[sqrt(1+z) -1]*c/H(0)

Imagine a light beam going from earth to a distant star and arriving a time t later. We have speed of light c, and further away c(t) = cexp(-Ht). (This is opposite to usual i.e. light goes from star to earth, but gives the same distance and seems easier to imagine.)

If we integrate (speed of light)*time
d=integral[from 0 to t of cexp(-Ht)] dt

d=c/H*(1-exp(-Ht))
H is the rescaling constant, half of Hubbles constant H(0)

In rescaling theory 1+z = exp(2Ht) so
d=2c/H(0) *(1-1/(sqrt(1+z))

which simplifies to d = 2c/H(0)*[sqrt(1+z) - 1]/sqrt(1+z).
This is how the distance depends on redshift.

-------------------------------

The size of an object, further back in time depends on 1/sqrt(1+z) in rescaling theory, (i.e. exp(-Ht)),
which makes the angular diameter distance dA smaller i.e. actual size / angle subtended

dA= 2c/H(0)*[sqrt(1+z) - 1]/(1+z)

measured Flux = Luminosity/(4*pi*dL^2)

and luminosity distance dL = dA*(1+z)^2 = 2(1+z)*[sqrt(1+z) - 1]*c/H(0) from Hoggs paper (formula 21)

This is the formula which gives a good match to the supernovae data, without dark energy, derived more rigorously.

John Hunter.

Cougar
2007-Aug-15, 03:06 PM
the point of rescaling symmetry is that it is undetectable, so you can't prove that it isn't happening.
Well, that's convenient. Is this even science? What good is it? Although there seems to be a trend in contemporary science to investigate mathematically interesting systems that we may not have the technology to test for hundreds of years or longer, I don't think this is a particularly good bandwagon to be jumping on just because "you can't prove it's NOT." What happened to "here is what is observed; here is my proposed explanation..."?

antoniseb
2007-Aug-15, 04:04 PM
Hi john hunter,

what would you call the energy that makes the everything in the universe get bigger at a uniform rate? Is it something otherwise visible, or is it dark?

coliver
2007-Aug-15, 10:51 PM
Why do we assume that an initial "fluid" making its own space spreads faster than the speed of the energy limit?

Surely that only happens in any fluid only if it is added to an existing fluid.

Simple experiment:-
1. pour oil into a pan.
2. note it is resisted while spreading
3. add some more oil
4. note it spreads faster by spreading the original oil

Why does the perfect fluid of the big bang act so differently to any other fluid?
But arent there varying densitys of fluid as you progess outward in space? That would either speed up or slow down the velocity as well. Like oil and water.

john hunter
2007-Aug-16, 09:31 AM
Dear Cougar,


What happened to "here is what is observed; here is my proposed explanation..."?

Supernovae magnitudes have been observed against redshift. Standard Big Bang could not explain them. Here is the explanation www.rescalingsymmetry.com (page 4).

WMAP has observed an omega(matter) of about 0.25. The explanation is on the same website, page 3.

This is definitely science.

John Hunter.

john hunter
2007-Aug-16, 09:35 AM
Dear antoniseb,


Hi john hunter,

what would you call the energy that makes the everything in the universe get bigger at a uniform rate? Is it something otherwise visible, or is it dark?

No energy is required for the rescaling. For each mass G is determined by the requirement that mc^2 - GmM/R = 0 , and remains at zero during the rescaling.

Thus rescaling theory gives a very natural solution of the flatness problem, hence omega(matter) = 1, but is measured as 0.25. website page 3.

Jonh Hunter.

john hunter
2007-Aug-16, 09:54 AM
Note to Nereid,

Post 16 has been edited today, to correct a small error, under the dotted line.

John Hunter.

Nereid
2007-Aug-17, 04:25 PM
[snip]

According to rescaling theory every physical constant rescales according to the number of length dimensions in it.

[snip]Just so that I'm quite clear on this ...

G (Newtonian constant of gravitation) (re)scales as L3?

the electric constant (re)scales as L?

λC (the Compton wavelength) (re)scales as L?

How does the Stefan-Boltzmann constant (re)scale?

john hunter
2007-Aug-18, 09:59 AM
Dear Nereid,

The rescaling depends on the number of length dimensions in the physical constant.

Yes, G rescales as L^3 i.e. exp(3Ht)

The electric constant, if you mean e^2/(4*pi*epsilon) has length dimensions of metres^3, so is also exp(3Ht)

The Stephan-Boltzmann constant is usually quoted as 5.67x10^-8 Wm^-2K^-4, since Watts has m^2, it's got zero length dimensions, so exp(0Ht) = constant.

Compton wavelength rescales as exp(Ht) etc...

some other things which are constant:

mass
time
temperature
fine structure constant
Hubbles constant H(0) and rescaling constant H (half of Hubbles constant).... as all have zero length dimensions.

John Hunter

Nereid
2007-Aug-18, 03:27 PM
1) How does the apparent size of a standard ruler (orthogonal to the line of sight) vary, with distance?

2) How does alpha (the fine structure constant) vary, in this john hunter idea?

3) How about the other coupling constants (http://math.ucr.edu/home/baez/constants.html) (not mass)?

4) I didn't see where, in these four pages, you showed your idea was consistent with GR; would you mind saying a few words about the extent to which it is?

5) Specifically, in what ways are gravitational lenses different, in a john hunter universe, than in a GR universe?

6) In this john hunter idea, what is (are) the cause(s) of the observed angular power spectrum in the CMB?

7) How did the apparent asymmetry between matter and anti-matter arise, in this john hunter cosmology idea?

8) How does this idea address the observed relative primordial abundance of light nuclides?

(That'll do for now; later I might ask about the ISW and BAO).Bumping this, and adding numbers ... it seems that you have provided at least some kind of response to 1), 2), 7), and 8).

Did I miss your response(s) re 3), 4), 5), and 6)?

If not, when do you expect to answer these questions?

john hunter
2007-Aug-20, 09:44 AM
Dear Nereid,

Thanks for the moderating so far, it must be difficult to keep track of all these ATM ideas!

About 3) - coupling constants.

Rescaling theory deals only with gravity so far - and explains it as being necessary in a universe with rescaling symmetry, which conserves energy.

------------------------
For 4) It may be that only a reinterpretation of GR is necessary. In fact a future theory of gravity must be compatible with GR, but with the value of G determined by the symmetry mentioned above in 3).

A few more words on the reinterpretation. Standard cosmology uses GR and believes that the size or 'scale factor' of the universe can change depending on gravity and maybe a cosmological constant...and these changes apply to space but not to the size of objects.

In rescaling theory, GR should be retained but the scale factor determines the size of space and objects (so named rescaling). Changes in the scale factor cause gravity, so that energy is conserved. For each mass mc^2 - GmM/R = 0, always, (M is mass of universe, R is radius of universe).

So G is determined by the rescaling constant H, and there is a natural solution of the flatness problem.

H is the fundamental constant, and gravity dosn't change its value.

The advantages of this interpretation as well as the above, are that there is a natural solution of Einsteins equations, a De Sitter solution, with k=0, lambda = 0, G = 3H^2/8*pi*rho.

This gives the measured value of omega(matter) of 0.25, as in WMAP, as H is half of H(0).

There is also a very good match to the supernovae data, without dark energy and with a constant value of H.

John Hunter.
---------------------------

P.S motion of matter in the rescaling universe can still occur, totally independently of the rescaling, so there can still be a 'Big Bang', which occurs due to a reduction of G for matter with m/r ratio approaching c^2/G.

john hunter
2007-Sep-01, 09:32 AM
Dear Nereid,

You gave no reply on 3) and 4).

For 5) There would be no difference between standard Big Bang and the rescaling model for lensing, unless the object causing the lensing has m/r ratio of the order of c^2/G.

For 6) the angular power spectrum is the same as for standard Big Bang model as the rescaling model incorporates the Big Bang model.

John Hunter

john hunter
2007-Sep-08, 10:32 AM
Well the 30 days is nearly up. Bye.

What's happened to ATM?

John Hunter.

Nereid
2007-Sep-09, 01:47 AM
It is of interest to note that Nereid is not the only BAUT member (other than john hunter, of course).

Wrt the ATM idea presented here, I wonder whether this preprint has pertinence?

Starburst Intensity Limit of Galaxies at z~5-6 (http://arxiv.org/abs/0709.0520); abstract:
The peak star formation intensity in starburst galaxies does not vary significantly from the local universe to redshift z~6. We arrive at this conclusion through new surface brightness measurements of 47 starburst galaxies at z~5-6, doubling the redshift range for such observations. These galaxies are spectroscopically confirmed in the Hubble Ultra Deep Field (HUDF) through the GRism ACS program for Extragalactic Science (GRAPES) project. The starburst intensity limit for galaxies at z~5-6 agree with those at z~3-4 and z~0 to within a factor of a few, after correcting for cosmological surface brightness dimming and for dust. The most natural interpretation of this constancy over cosmic time is that the same physical mechanisms limit starburst intensity at all redshifts up to z~6 (be they galactic winds, gravitational instability, or something else). We do see two trends with redshift: First, the UV spectral slope of galaxies at z~5-6 is bluer than that of z~3 galaxies, suggesting an increase in dust content over time. Second, the galaxy sizes from z~3 to z~6 scale approximately as the Hubble parameter 1/H(z). Thus, galaxies at z~6 are high redshift starbursts, much like their local analogs except for slightly bluer colors, smaller physical sizes, and correspondingly lower overall luminosities. If we now take the constancy of star formation intensity as a given, our observations provide a basis for a strong Tolman test: We should expect the observed surface brightness of z~6 galaxies to differ by factors of ~7^3 ~ 300 between a standard expanding cosmology and alternatives such as ``tired light''.The authors apparently claim all kinds of alternative cosmologies are ruled out, to a high degree of certainty, by what they present in the (preprint) paper.

How strongly (or not) does the paper also rule out the ATM idea presented in this thread?

Nereid
2007-Sep-09, 08:49 PM
Dear Nereid,

You gave no reply on 3) and 4).

For 5) There would be no difference between standard Big Bang and the rescaling model for lensing, unless the object causing the lensing has m/r ratio of the order of c^2/G.

For 6) the angular power spectrum is the same as for standard Big Bang model as the rescaling model incorporates the Big Bang model.

John HunterCan you expand on both of these please, to show in some detail that the ATM idea you are presenting is indeed the same, wrt gravitational lensing (with the caveat you entered) and the angular power spectrum.

I'm particularly interested in the latter, and how you can show it ... independent of what its cause is, in any (LCDM, jhunter ATM) cosmological model.

Nereid
2007-Sep-09, 08:58 PM
[snip]

This gives the measured value of omega(matter) of 0.25, as in WMAP, as H is half of H(0).

There is also a very good match to the supernovae data, without dark energy and with a constant value of H.

[snip]There are, as I think you know, three somewhat independent sets of observations that lead to a 'dark energy' conclusion: the high-z (Type Ia) supernovae, analysis of WMAP (and other) observations of the angular power spectrum of the CMB, and P(k), the matter power spectrum (i.e. 'large-scale structure').

They are not fully independent; for example, H0 is degenerate in LCDM model fits to WMAP CMB angular power spectrum analyses.

My question - which is, unfortunately, somewhat ill-formed - is how does your ATM idea fare when compared with all three sets of observations?

I'm particularly interested in P(k), because - if I've understood your idea correctly - it will be significantly different than that predicted by an LCDM model, using H0 within a sigma or two of the Hubble Key Project's estimate.