Is the Redshift of Distant Objects Due to Expansion or Gravitational Effects?

[turbo]

All other issues aside, a mathemetician who is asked to explain cosmological redshift (more distant objects regularly appear redshifted) could easily come up with a couple of reasons:

1) the universe is expanding rapidly in all directions, and the light from distant galaxies is redshifted due to that expansion. The expansion is driven by dark matter, which we can't detect, but must be real because it fits the models for expansion.

2) our frame of reference is contracting with respect to the universe at large, and instead of all the galaxies shooting away from us, we are receding from one another into our gravity wells. The dark matter isn't needed to supply the expansion, because there isn't any expansion.

If our local neighborhood were receding into a steep gravity well, like the black holes postulated to lie at the hearts of galaxies, would we not see light from more and more distant objects more and more redshifted?

If so, it seems to me that situations 1 and 2 are mathematically equivalent. It also appears that situation 2 is by far the more likely, since we don't have to include a fudge factor like dark matter that says in essence "this is how it is, and it's mathematically consistent, except that we have to posit the existence of massive amounts of unseen energy that we can't explain and may never begin to measure". I may be missing something critical here, but it seems invoking dark matter to justify cosmological expansion is one step short of laying the blame to angels. Occam's Razor says that given two equally plausible explanations for a circumstance, the simpler one is the right one.

I know that cosmologists are pretty well locked into the expanding universe world view, and tenure and research support do not favor contrarians, but is there anybody who from a purely mathematical stance is presently exploring the possibility that each galaxy might be receding into its own gravity well producing the redshifts that we see. Objects in a steady-state universe could appear more and more redshifted the more distant they are from us and the longer the time the light had to travel. We shouldn't have to think about light being "tired", or other constructs. We should be able to think of it as invariable, with the variances being due to the changes between the states of the emittor and the receptor. Changes in relative physical position (Doppler effect) should be much smaller than (but empirically identical to) changes in acceleration, as in the effects due to the differences in gravitational gradient.

I know my terminology may not be up to date, but I watched Kip Thorne's presentation on space/time recently, and I was struck with the way that steep mass/gravity gradients can distort space-time. It occurred to me then that looking for the "missing" 95% of the mass of the universe might be avoided if we adopted a steady-state model and attempted to explain the differences between the states of our neighborhood and more distant objects in more practical terms.

 

[meteor]

1)It's not dark matter, but dark energy what is causing the acceleration of the expansion
2)If you are able to find a solution of the Einstein field equations in which whole galaxies are falling inside a gravitational well, then possibly you will win the Nobel Prize. Nowadays, the Robertson-Walker metric with the adding of a cosmological constant explain reasonably well the observations

 

[Nereid]

meteor said it "... explain reasonably well the observations."

If the redshift-distance relationship were between mere unresolved points of light with completely uniform spectra (gammas to radio), trubo-1's mathematician friend would really be onto something.

However, a great many of the objects whose redshifts we can observe with considerable accuracy are not just point-spread functions in the camera, or not just quite uninformative spectra. So, for example, we see that there are galaxies that look just like those in the Local Group (whose distances aren't determined by their redshifts), complete (in many cases) with SMBHs in their nuclei. Makes interpretation 2) rather difficult to square with the observations, doesn't it?

 

[Garth]

Indeed there is a theory that describes your second option; it is Self Creation Cosmology. You will find the latest paper, "Self Creation Cosmology - An Alternative Gravitational Theory" at http://arxiv.org/abs/gr-qc/0405094 , it is to be published in 'Progress in General Relativity and Quantum Cosmology Research', Nova Science
Publishers, Inc. New York.

 

[Nereid]

Welcome to Physics Forums Garth!

An interesting paper. Maybe we could provide it as a model, in the Theory Development sub-forum, of the kind of thing which folk who aspire to develop an alternative to today's text-book physics (and cosmology) might consider. (Note: I'm NOT saying that I think Garth* Barber's idea really has legs - we can discuss that later - rather that he has obviously done much of the necessary 'homework' before presenting the idea).

Why does the paper look as if it could be such a model? It:
1) explains the new theory (OK, nearly everyone with a new idea does this)
2) shows how the new idea relates to existing observations and data; in this case, that it is consistent with all (nearly all?) of the tests of GR done to date (GPB excepted, but there are no results from that yet), WMAP, distant Type Ia supernovae, primordial nuclide abundance, Hubble redshift, etc
3) suggests some experiments which could be used to test the new idea, and makes predictions of what the results would be (inc cf today's standard theories)
4) accommodates some apparently solid, anomalous results, in this case the Pioneer anomaly, Morrison and Stephenson's residual length-of-day changes (ancient solar eclipse analyses; I'd not heard of this previously), solar system celestial mechanics data hinting at a secular change in G (I hadn't heard of this before either)
5) briefly summarises how the idea fits with current observational cosmology.

*Any relation to the new PF member Garth, I wonder?

 

[Nereid]

Indeed there is a theory that describes your second option; it is Self Creation Cosmology. You will find the latest paper, "Self Creation Cosmology - An Alternative Gravitational Theory" at http://arxiv.org/abs/gr-qc/0405094 , it is to be published in 'Progress in General Relativity and Quantum Cosmology Research', Nova Science
Publishers, Inc. New York.

Leaving aside Morrison and Stephenson's residual length-of-day changes (ancient solar eclipse analyses) and the solar system celestial mechanics data hinting at a secular change in G (I need to go check these out first), some comments on fitting with present data and experiments, and proposed ones:
- how well will planned space missions, such as LISA test this SCC idea?
- what other observations and experiments have been done on time changes in G? Garth's paper mentions just two, one possibly consistent with SCC, the other not inconsistent (null result expected in both SCC and 'G is truly constant')
- nuclide abundances: more work on expected ²H and ³He vs ⁴He; also "one prediction of the theory is that a significant proportion of intergalactic medium metallicity, observed from the Lyman a forest of distant quasar spectra, should be primordial"; there's surely tonnes of data on abundances which can be used to test the SCC predictions
- dark matter. It's not only WMAP data and cosmology models which point to DM, there's a wide range of observations which are interpreted in terms of DM (I'll include a link here to some of my earlier posts on this topic*). If in SCC "this component [DM] of the cosmic density parameter is in the form of intergalactic cold baryonic matter", then all those other "DM" observations need to be explained (not just the 'cosmological' ones). Also, if there is so much cold baryonic matter, why haven't we seen it yet?
- LSS (large scale structure) and galaxies. Similar story to DM, though as Barber correctly notes, the observational data doesn't constrain models much yet (e.g. "[the concordance cosmology models predict] galaxy mass profiles that have a too pronounced cusp at small scales and a too steep galaxy luminosity function")

*Here's one with a discussion of the IGM; there are several on DM, this one may be a good one to start with (also relevant to turbo-1's threads)

 

[Nereid]

Just remembered; outandbeyond2004 gave us a post a while ago, with a link to some very cool work done with ring lasers. It's not quite the same as the Garth's proposed space-based test, but maybe the sensitivities etc that the group have attained, and their understanding of the set-up, may lead to a 'test' involving analysis of data already on hard-drives! After all, if they think they may be able to detect the motion of the solar system wrt Sag A* ...

 

[Chronos]

All other issues aside, a mathemetician who is asked to explain cosmological redshift (more distant objects regularly appear redshifted) could easily come up with a couple of reasons:

1) the universe is expanding rapidly in all directions, and the light from distant galaxies is redshifted due to that expansion. The expansion is driven by dark matter, which we can't detect, but must be real because it fits the models for expansion.

2) our frame of reference is contracting with respect to the universe at large, and instead of all the galaxies shooting away from us, we are receding from one another into our gravity wells. The dark matter isn't needed to supply the expansion, because there isn't any expansion.

If our local neighborhood were receding into a steep gravity well, like the black holes postulated to lie at the hearts of galaxies, would we not see light from more and more distant objects more and more redshifted?

If so, it seems to me that situations 1 and 2 are mathematically equivalent. It also appears that situation 2 is by far the more likely, since we don't have to include a fudge factor like dark matter that says in essence "this is how it is, and it's mathematically consistent, except that we have to posit the existence of massive amounts of unseen energy that we can't explain and may never begin to measure". I may be missing something critical here, but it seems invoking dark matter to justify cosmological expansion is one step short of laying the blame to angels. Occam's Razor says that given two equally plausible explanations for a circumstance, the simpler one is the right one.

I know that cosmologists are pretty well locked into the expanding universe world view, and tenure and research support do not favor contrarians, but is there anybody who from a purely mathematical stance is presently exploring the possibility that each galaxy might be receding into its own gravity well producing the redshifts that we see. Objects in a steady-state universe could appear more and more redshifted the more distant they are from us and the longer the time the light had to travel. We shouldn't have to think about light being "tired", or other constructs. We should be able to think of it as invariable, with the variances being due to the changes between the states of the emittor and the receptor. Changes in relative physical position (Doppler effect) should be much smaller than (but empirically identical to) changes in acceleration, as in the effects due to the differences in gravitational gradient.

I know my terminology may not be up to date, but I watched Kip Thorne's presentation on space/time recently, and I was struck with the way that steep mass/gravity gradients can distort space-time. It occurred to me then that looking for the "missing" 95% of the mass of the universe might be avoided if we adopted a steady-state model and attempted to explain the differences between the states of our neighborhood and more distant objects in more practical terms.

Substituting dark energy for dark matter, if you don't mind: Gravitational red shift and doppler red shift have different implications. If you substitute gravitational force for acceleration as an explanation for red shift, you end up with a universe that collapses before we have enough time to observe it. The cosmological constant is necessary to explain why the universe has endured long enough for us to witness it. Dark energy is necessary to explain the repulsive force required to resist gravitational collapse.

 

[Garth]

Yes indeed the new PF member Garth is the author of the SCC papers. It is good to have a decent critical discussion about the theory. Key points about the theory are 1. test particles follow the geodescis of GR so all standard tests that verify GR also do so for SCC. 2. G is inversely proportional to M so GM is constant. Most tests on the variability of G actually test GM and therefore give a null result. The intergalactic DM has been observed; it is the Lyman alpha forest observed in distant quasar spectra. Only about 20% of which can be explained from galactic outflow, the rest may well be primordial. I was waiting for somebody else to pick that point up! The theory will be tested soon - GPB should enter its science phase at the end of this month.

 

[turbo]

Garth, is your paper near release? I will be very interested to see the implications of local conservation of energy...

 

[Chronos]

Garth, getting rid of dark matter and dark energy is very attractive. I resent unobservable features of the universe. And having testable predictions is also attractive. I look forward to the experimental results. My main concern is how your model behaves thermodynamically. It appears there is more wiggle-room for Lorentzian invariance than expected. Not a bad thing [Lorentz was not a nice person, Einstein was a very nice man]. Your predictions should make or break the case either way. Excellent work, regardless of the results.

ps: i despise string theory. Those annoying extra dimensions make the math too hard for me to follow.

 

[Garth]

The SCC theory was published in 2002, a paper is appearing as a chapter in 'Progress in General Relativity and Quantum Cosmology Research', Nova Science Publishers, Inc. New York to be published later this year. A brief description and references to the six papers on SCC can be found in the Theory Development sub-forum https://www.physicsforums.com/showthread.php?t=32713.

 

[Mike2]

So what is the mathematical relationship between the velocity of galaxies and the redshift of the light we see from them? Does this formula take into account both Dopler effects and gravitation?

Thanks.

 

[sol2]

Maybe Garth can speak to the ideas of Glast and speak accordingly about Redshift and Blue shift from this perspective?

 

[Garth]

There are two frames of measurement in my theory, the Jordan frame and the Einstein frame. In the Einstein frame energy-momentum is conserved and a particle's mass is constant. The universe expands linearly from a big bang. As in normal GR gravitational red shift can be seen either as a doppler effect as the galaxies receed from each other, or a gravitational effect due to the fact that light coming from early in the universe's history was emitted deep down within the cosmological gravitational well. Both expalnations are equivalent, they are different ways of interpreting the same effect. However in my theory in the Jordan frame energy is locally conserved and a particle's mass varies with gravitational potential energy. Here a particle increases expontentially with cosmological time [m(t) = m' exp(Ht)] and atoms and rulers consequentially shrink with time. The expanding universe with fixed rulers is reinterpreted as a static universe with shrinking rulers.Cosmological red shift is due not to a doppler effect, or to a 'tired light' effect, but instead the photon maintains a constant energy and it is the atoms it interacts with that increase in mass. When the energy of photon is compared with the mass of the atom it interacts with the photon appears to have lost energy and a red shift is observed.

 

[Mike2]

... Here a particle increases expontentially with cosmological time [m(t) = m' exp(Ht)] and atoms and rulers consequentially shrink with time. ... and it is the atoms it interacts with that increase in mass. When

I would think that if a photon loses energy and is redshifted because it gains potential energy (since it distances to gravitating objects increases as the universe expands), then so must any particle's rest mass decrease when it gains potential energy. For there should be no difference between photons losing energy as the universe expands, and those same photons being converted to mass first, the universe expand, and then those particles be converted back to photons. So if the photon loses energy then so do any particles that could be made from it.

So... if rest mass is decreasing with expansion, then were things heavier in the past? Is this the source of the extra mass (dark matter) we see in ancinet galaxies? Is the gravitational lensing more powerful in the far past then in the near past?

 

[Garth]

First please pardon my typos, I type in a hurry and seem to be unable to proof read on the monitor screen!
You have it the wrong way round! A particle's mass increases with cosmological time. (It is the size of an atom and frequency of atomic vibrations, which are inversely proportional to mass, that decrease - I think this is where your confusion lies) Secondly a key feature of the theory is the principle of mutual interaction, which is described in my papers. The increase of mass-energy affects massive particles like atoms but not massless relativistic photons and the like. This increase is a result of the acquisition of inertial mass by particles determined by Mach's Principle. A free photon is of constant energy, after all no work is being done on or by it, and it is the atom it interacts with that gains mass - energy over time. Secondly G is inversely proportional to mass so GM is constant. It is always GM that is measured and that is why measurements of gravitational lensing and variation of G give a null result. Finally this increase of mass does affect the Earth and shoul mean that the Earth is spinning up at the rate of Hubble's constant. This is indeed observed from ancient eclipse records - see my papers - but it has not been recognised as such - yet.

 

[sol2]

Garth,

In comparison, from your perspective?

http://ws2004.ift.uni.wroc.pl/Lectures/Amelino-Camelia/gacKarp.pdf

Do you see correspondances that would support your position?

Regards,

 

[Mike2]

So... if rest mass is decreasing with expansion, then were things heavier in the past? Is this the source of the extra mass (dark matter) we see in ancinet galaxies? Is the gravitational lensing more powerful in the far past then in the near past?

If space itself is expanding, then the increase in potential energy due to distance is not accompanied by a equal decrease in kinetic energy. For such formula apply only with respect to a coordinate system that does not change from initial to final states. So in order for energy to be conserved, I supose the rest energy of particles must decrease as space itself expands. What do you think?

 

[Chronos]

There is no net energy loss. Thermodynamics forbid it. Garth, one thing i object to in your theory relates to information theory. There cannot be any Shannon information in the universe. I don't have the math at hand to support that supposition, so my position is not defendable. So, it is no more than a postulate. I do, however, believe it strongly agrees with observations.

 

[Garth]

1. sol2 - a quote from the paper you referenced "QFT needs a fixed spacetime arena in order to describe the motion of particles in that arena, but when GR effects cannot be neglected spacetime is the RESULT of the analysis rather than a PREMISE of the analysis." My questions (see my thread https://www.physicsforums.com/showthread.php?t=32713) and my theory challenge the acceptance of the EEP. In the theory there is a preferred frame of reference as required both by Mach's Principle and the local conservation of energy; it is the centre of mass of the system. It is a preferred foliation of space-time in which QFT can be based. The observation of the spinning up of the Earth can be found "Morrison, L. & Stephenson, F.R.:1998, Astronomy & Geophysics Vol. 39 October. The Sands of Time and the Earth’s Rotation" and
"Stephenson, F.R.:2003, Astronomy & Geophysics Vol. 44 April. Historical
eclipses and Earth’s rotation." They reported that in addition to the tidal contribution there is a long-term component acting to decrease the length of the day which equals
△T/day/cy = −6 × 10^(−4) sec/day/cy. This just happens to be Hubble's constant (equivalent to 67 km/sec/megaparsec) but nobody apart from myself has recognised this!
2. Mike2 - space is not expanding - it is static, it is inertial masses that are increasing and hence rulers shrink, i.e. the same effect.
3. Chronos - just wait until Gravity Probe B produces some results and then we will know!

 

[Chronos]

Agreed. Gravity B will dispell many illusions. I am a big fan of GR. I used to think it was wrong. I was wrong, as it turns out. GR has passed every test imaginable with flying colors. That Einstein guy was pretty smart, so far as it appears.

 

[Mike2]

There is no net energy loss. Thermodynamics forbid it. Garth, one thing i object to in your theory relates to information theory. There cannot be any Shannon information in the universe. I don't have the math at hand to support that supposition, so my position is not defendable. So, it is no more than a postulate. I do, however, believe it strongly agrees with observations.

Curious, particles gather into galaxies and stars and planet, etc, while the universe in general expands. Expansion is a positive entropy event, while matter gathering is a negative entropy event. Does this in itself indicate that entropy is constant?

 

[Mike2]

Mike2 - space is not expanding - it is static, it is inertial masses that are increasing and hence rulers shrink, i.e. the same effect.

Are you proposing an eternally steady state universe that has always been the size it is today? The universe must have had a beginning in a small regions and expanded to today's proportion. Anything less would deny causality. To assert instant everything or eternal everything denies any cause for it. It is by definition illogical.

 

[turbo]

Are you proposing an eternally steady state universe that has always been the size it is today? The universe must have had a beginning in a small regions and expanded to today's proportion. Anything less would deny causality. To assert instant everything or eternal everything denies any cause for it. It is by definition illogical.

A steady-state universe with simultaneous emergence and annihilation of matter, whille not everyone's cup of tea, is no less illogical than a Big Bang. We perceive that we ourselves (as humans) have a beginning, a maturation, and an end, and we instinctively look for those qualities in the universe. Mankind has always tried to explain how "all this" came to be. If you can accept that the universe is infinite in extent, how can you reject out-of-hand the concept that it may also exist across an infinite span of time? The Big Bang cosmologists may be correct, and the universe spontaneously sprang into existence 13.7 B years ago, but if that is the case, where is your casuality? The model satisfies our human demand that there be a beginning, but it still leaves the big casuality question unanswered. Spontaneous emergence of a singularity resulting in a Big Bang is just as illogical from a casual standpoint as an eternal universe.

 

[Mike2]

A steady-state universe with simultaneous emergence and annihilation of matter, whille not everyone's cup of tea, is no less illogical than a Big Bang.

You've presupposed the unexplained existence of some underlying space in which these simultaneous emergences come forth. So you've denied the causality of space-time itself. The only way not to deny the causality of spacetime itself is if it too has a beginning from a singularity that expands with time.

If you can accept that the universe is infinite in extent, how can you reject out-of-hand the concept that it may also exist across an infinite span of time?

I don't accept that the universe is infinite in extent. I don't know anyone who does.

The Big Bang cosmologists may be correct, and the universe spontaneously sprang into existence 13.7 B years ago, but if that is the case, where is your casuality? The model satisfies our human demand that there be a beginning, but it still leaves the big casuality question unanswered. Spontaneous emergence of a singularity resulting in a Big Bang is just as illogical from a casual standpoint as an eternal universe.

Logic allows a true conclusion from a false premise; it allows something from nothing. So the universe may have come from a singular point.

Or it may be that the universe approaches infinite energy density as time is reversed to negative infinite. At minus infinity it occupies no space and does not exist.

What is not allowed is instant anything or eternally existing something.

 

[turbo]

You've presupposed the unexplained existence of some underlying space in which these simultaneous emergences come forth. So you've denied the causality of space-time itself. The only way not to deny the causality of spacetime itself is if it too has a beginning from a singularity that expands with time.

Not really, nor am I saying that a steady-state universe is more likely than the Big Bang model. I was simply pointing out that reasonable people have worked out models of steady-state universes. There is no reason for a steady-state universe to be less logical than a Big Bang-created one. Many people are drawn to the Big Bang because having a defined beginning is philosophically satisfying. It does not remove the problem of causality - it just relocates it to a very convenient miraculous event.

I don't accept that the universe is infinite in extent. I don't know anyone who does. (Snip) What is not allowed is instant anything or eternally existing something.

Many people are comfortable with the model of an open Friedmann-Lemaitre universe. In such a universe, there is not enough mass in the universe to stop expansion, spacetime is negatively curved (triangles total less than 180 degrees), and the universe is infinite in extent and duration. If CDM exists, it may swing the balance from an open universe to a flat or closed universe. So far, it has not been observed, though, so the universe may well be open.

In particular, Hawking and Turok have been working on a model that leads from the Big Bang to an open universe.

http://citebase.eprints.org/cgi-bin/citations?id=oai:arXiv.org:gr-qc/9803050

 

[Nereid]

The intergalactic DM has been observed; it is the Lyman alpha forest observed in distant quasar spectra. Only about 20% of which can be explained from galactic outflow, the rest may well be primordial. I was waiting for somebody else to pick that point up! The theory will be tested soon - GPB should enter its science phase at the end of this month.

Several types of observation are used to conclude the existence of inter-galactic DM ... What's detected in the Lyman alpha forest is baryonic matter (mostly H and He); what's 'seen' in Abell clusters (such as this one) is mass creating gravitational lensing (and holding the gas which gives rise to the X-rays seen from such clusters from escaping, etc). But what is it in Garth's SCC theory?

DM is a very troublesome thing to deal with in any alternative cosmology, because there are so many types of observations that need to be accounted for (if your alternative cosmology lacks DM) - not just the CMBR - and all searches for baryonic forms of this DM have come up essentially empty handed.

 

[Garth]

Nereid - "DM is a very troublesome thing to deal with in any alternative cosmology"; is it not also troublesome in GR? If not what is it?
All observations of DM are theory dependent, that theory being GR; change the theory and those observations change too.

 

[Chronos]

I hate the dark matter explanation. But, I have looked and not found a better explanation as to why it must exist. The only alternative appears to be that both the theory of gravity and GR are fundamentally wrong. Inasmuch we have no shred of evidence that either theory is [beyond a quantum fluctuation of doubt] the least bit flawed, what are the alternatives? [and i want to see the math. pseudo-logical arguments will not suffice].

 

[Mike2]

I hate the dark matter explanation. But, I have looked and not found a better explanation as to why it must exist. The only alternative appears to be that both the theory of gravity and GR are fundamentally wrong. Inasmuch we have no shred of evidence that either theory is [beyond a quantum fluctuation of doubt] the least bit flawed, what are the alternatives? [and i want to see the math. pseudo-logical arguments will not suffice].

What's wrong with my previous argument: "If space itself is expanding, then the increase in potential energy due to distance is not accompanied by a equal decrease in kinetic energy. For such formula apply only with respect to a coordinate system that does not change from initial to final states. So in order for energy to be conserved, I supose the rest mass of particles must decrease as space itself expands. What do you think?" Honestly, that argument seems infallible. GR supports expanding spacetime and a gobal conservation of energy. So why would rest mass decreasing with expansion not be included in GR? Is this equal to a change in the gravitation constant of the universe?

If it is, then the question remains. Could the extra mass we see be due to heaver particles in the past?

 

[Nereid]

Nereid - "DM is a very troublesome thing to deal with in any alternative cosmology"; is it not also troublesome in GR? If not what is it?
All observations of DM are theory dependent, that theory being GR; change the theory and those observations change too.

To be sure.

Then the critical question becomes: how do these alternative (GR, cosmology) theories account for the observations which, in the concordance model, are accounted for by DM? To paraphrase Chronos, hand-waving about it being different and no long a problem (trust me), just will not do.

Take a specific example: in Abell 1689, analysis of the lensed images (of more distant galaxies) implies far more mass in the lens than can be accounted for with tried-and-true astrophysics (stellar, gas, dust components of ellipticals; stellar luminosity functions; optical/X-ray/IR absorption spectra; far-IR emission; etc, etc, etc). Even taking all inputs at values most favourable to more mass (and still - barely - consistent with observational data), you're left with a 'mass gap' or 'missing mass' of truly galactic proportions. In SCC (or any other alternative), how to account for this missing mass? If SCC (or other alternative) produces different gravitational lensing ('bending of light') properties than in GR, then a) show that the Abell 1689 lens mass is consistent with the mass expected from optical/X-ray/etc observations (you may have to re-write large chunks of 'textbook astrophysics' to do this!), and b) show consistency with all high-quality lensing/bending experiments and data (e.g. Pound-Rebka, Cassini).

 

[Nereid]

What's wrong with my previous argument: "If space itself is expanding, then the increase in potential energy due to distance is not accompanied by a equal decrease in kinetic energy. For such formula apply only with respect to a coordinate system that does not change from initial to final states. So in order for energy to be conserved, I supose the rest mass of particles must decrease as space itself expands. What do you think?"

To quote Chronos: "I want to see the math. pseudo-logical arguments will not suffice."

Honestly, that argument seems infallible. GR supports expanding spacetime and a gobal conservation of energy. So why would rest mass decreasing with expansion not be included in GR? Is this equal to a change in the gravitation constant of the universe?

It might, or it might not be (depends on the math that you're going to give us ). However, it certainly won't remove the need for DM!

For example, here is the inferred distribution of DM in a distant (z = 0.4) rich cluster, located at RA 00h26m35s, Dec 17d09m38s. Some kind of global, universal change in the properties of matter of the kind you're proposing would surely result in ALL matter at z = 0.4 changing, not just that in a rich cluster. Further, how would your proposed change account for the observed DM mass/density profile in Cl0024+1654?

If it is, then the question remains. Could the extra mass we see be due to heaver particles in the past?

Show us how (be sure to clearly demonstrate the vastly different inferred DM profiles in near and far galaxies, clusters, lenses, etc.

 

[Mike2]

For example, here is the inferred distribution of DM in a distant (z = 0.4) rich cluster, located at RA 00h26m35s, Dec 17d09m38s. Some kind of global, universal change in the properties of matter of the kind you're proposing would surely result in ALL matter at z = 0.4 changing, not just that in a rich cluster. Further, how would your proposed change account for the observed DM mass/density profile in Cl0024+1654?Show us how (be sure to clearly demonstrate the vastly different inferred DM profiles in near and far galaxies, clusters, lenses, etc.

I'm not sure my proposal would negate the evidence for DM. At this point I'm only curious. And I suppose that if matter was heavier in the past, then you would have more of a gravitational lensing effect for farther objects than for nearer. I also wonder if heavier matter would account for the otherwise strange orbital characteristics of the spiral arms of galaxies. If Andromida has this same strange orbital characteristic to the same extent as far away galaxies, then my proposal is shot down.

The math would be the same as for photons being redshift due to gravitation. I have doubts at this point though. My argument here may be negated if the velocity due to the expansion of space itself can be added to the total velocity of distant galaxies. Then the increase in kenitic energy due to velocity increase IS matched by the increase in potential energy due to distance. So the question is: Does the expansion of space itself add to the overall kenitic energy of distant object?

 

[Mike2]

My argument here may be negated if the velocity due to the expansion of space itself can be added to the total velocity of distant galaxies. Then the increase in kenitic energy due to velocity increase IS matched by the increase in potential energy due to distance. So the question is: Does the expansion of space itself add to the overall kenitic energy of distant object?

Some have said that the rate of expansion can be faster than the speed of light. If that were so, then the relativistic mass of receeding galaxies would go to infinity and the gobal conservation of energy would be shot. So it must be that the rate of expansion does not contribute to the momentum and kinetic energy, if the expansion rate can be faster than light.