[Colin2B]

Or the experiment that I suggest as to placing clocks at different locations at same elevation, but of different geological density would also be 'just' a variation of g.

And GP.

As I mentioned earlier, there is another prediction that should be made by your paper and that is that rapidly varying gravitational fields should cause varying red shifts of light passing through that field. So binary systems should show this effect for stars behind them. Check examples and you have your effect.
This is also the point @jeffreyH is making in #1055.

[alancalverd]

Or a slowly varying field such as the moon.  Too big, too well characterised, too predictable, and too obvious.

[Colin2B]

.. too obvious.

Too obvious to be accepted methinks!

[timey (OP)]

Light leaves the sun and is redshifted away from the sun, and blueshifted towards earth, and reaches our detector. Hey presto, we have an observation of light.

Along comes an eclipse. The moon has moved between the earth and the sun.
We have a variation in the field.
The light is redshifted away from the sun, it is blueshifted towards the moon, it is redshifted away from the moon, and it is blueshifted towards earth, and reaches our detector.  Hey presto we have the same observation that we had before.

Nothing has changed!  Why is that?
Source gravity, plus moon gravity, minus moon gravity, minus receiver gravity = gravitational shift.

Let's try that again:
Light leaves source in galaxy cluster, travels into dust cloud, out of dust cloud, into another galaxy cluster, out of this other galaxy cluster, into our galaxy cluster, and reaches our detector on earth.
Source galaxy cluster gravity, plus dust cloud gravity, minus dust cloud gravity, plus other galaxy cluster gravity, minus other galaxy cluster gravity, minus our galaxy cluster gravity=gravitational shift.

So -  any variations of 'clumped mass' in the field that the light travels 'past', it can be seen that while these masses will affect the light, this will have no effect on the final redshift observation' at 'receiver'.
Alan posted this 'fact' already, many posts ago, I thought we all understood that my model is no different to expanding model in this respect.

The difference in my model is that the galaxies that make up the galaxy clusters have been, and still are moving closer together as time passes, and this will change the field that the light travels through. The entire field.  And it is these changes in the entire field that cause the greater part of the shift of redshift observations (in my model).

However, it may be that the GPS archived data could be used as evidence of variation of g with regards to the variations of gravity that the moon elicits on the field.
The GPS system will be making adjustments for this effect, and yes it is hard to imagine that it would be missed that an increase in g would cause anything but a slowing of time.
This same conundrum exists within the structure of the Shapiro experiment.

But I see a possibility (via curvature and length contractions) that these same maths can be modified (turned upside down and inside out), to describe my contracting model, and this will tally up with observation.
Yes - of course there is a high probability that I am wrong, but I do provide a testable prediction with which my model can be falsified.

@Colin2B
Yes - if mass is increased, g is increased, and gp is also increased.

[alancalverd]

The difference in my model is that the galaxies that make up the galaxy clusters have been, and still are moving closer together as time passes, and this will change the field that the light travels through. The entire field.  And it is these changes in the entire field that cause the greater part of the shift of redshift observations (in my model).

Suppose the photon is travelling in direction x→ from a source at x₀  . At a particular point x it enters an infinitesimal region Δx where the gravitational potential is lower than the source, so it is blueshifted from the point of view of an observer inside Δx, then reaches the other side at x₁ = x + Δx where the gp is the same as at x₀ and is thus seen by an observer at that point to have no shift. You can have as many versions of Δx in series as you like, but that fact remains that the shift observed at any point x_n depends only on the difference in gp between the source and the receiver.

[timey (OP)]

OK Alan, but while your consideration takes into account the gravitational mass clumps of source and receiver, it doesn't take into account the rest of the gravitational mass clumps, or the gravity fields between all of the galaxy clusters.

Light leaves source. The source of the light is a star in a galaxy, in a distant galaxy cluster that is 1billion light years away.  When the light left the light source, 1 billion years ago, the galaxies of that galaxy cluster were not as close together as they are today when the light arrives at our detector.  Furthermore, the galaxies of every galaxy cluster in the universe were not as close to each other 1 billion years ago as they are today when the light hits our detector.

Let's just say we concentrate on an area containing 10 galaxy clusters, where the galaxies are becoming closer together over time.  The tracts of space between the galaxy clusters will be increasing as the space between the galaxies of the galaxy clusters reduces.

What is the 'open space' field gravity doing in the tracts of space between galaxy clusters?
Is it:
a) increasing in gravity
or
b) decreasing in gravity

[alancalverd]

It is a simple fact that whatever you see today is the result of what happened yesterday or 13 billion years ago, depending on where you look.

As you can see from my analysis in #1064, it doesn't matter what happened between the source and the detector: gravitational red shift depends only on the relative gravitational potentials at the time and place of the source and detector.

Energy is conserved. A photon starts its life with kinetic energy hf and an arbitrary potential energy dependent on the mass of its source. As it travels it may gain or lose potential energy by passing near other masses, but each such gain or loss is reflected by a change in f as seen by an observer at that point in space and is recovered as the photon leaves that point.

Imagine a frictionless ball rolling along a bumpy surface: it loses kinetic energy as it climbs a bump, and gains k.e. on the way down. Its final kinetic energy depends only on the initial k.e. and the height difference between start and finish.  The velocity of a photon is constant but its k.e. is its frequency.

[timey (OP)]

But the source and the receiver are not the only masses affecting the gravity of the intervening field between.

Analogy: Place 3 galaxy clusters in a triangle shape with equal distance between.  Place 5 galaxy clusters equally placed around the triangle.  Now let gravity take its course.  The galaxies of the galaxy clusters are converging on points within their clusters.  So, the distances between the galaxy clusters will get longer.

What happens if gravitational masses get further apart from each other?  Well, we know that gravity reduces by the inverse square law in the field, so clearly a longer distance between galaxy clusters is going to result in a weaker field.

OK, so in the expanding universe, the distance between galaxy clusters is getting longer really quickly, and in fact the further away the galaxy cluster is, the faster it is moving away.  The gravity in the distance between galaxy clusters will be near 0, the greater part of the observed redshift will be velocity related, and gravity shift will be source minus receiver.

But in a universe that is slowly contracting under the influence of gravity, the distances between galaxy clusters will be getting longer only as a result of galaxies of galaxy clusters getting closer to each other. The gravity in the distance between will be constantly weakening, where the amount of years that a photon travelled in these ever weakening fields contributes to it's redshift.  Photons arriving from galaxy clusters that are further away will have greater redshifts.

[alancalverd]

It seems that I cannot teach you anything about physics.

[Colin2B]

But the source and the receiver are not the only masses affecting the gravity of the intervening field between.

Alan isn’t saying that the source and receiver are the only masses affecting the field.
You are imagining a large area of density with light passing through and the density changing before the light has exited. But that’s not the way it works.
Imagine a string of infinitesimally small points along the path of the light. Each one has its own gp, caused by nearby mass, which affects the light as it enters and leaves (uphill down dale) so at the end of this string the sum result is that it is only the start and end values which matter.
Yes, the gp at each of those points will change with time but the light is long gone by the time that happens.
As I said in an earlier post, if your remit was correct you would see varying shifts in areas of intense changing g fields and we don’t.

[timey (OP)]

@alancalverd I don't need you to tell me how the expanding universe is calculated with regards to gravitational redshift.  The books I have read have informed me of this, and indeed it is b/c the expanding theory is calculated that way that a 'contracting' universe will be calculated oppositely.

@Colin2B. I already stated 10 times now that points of mass that the light moves past along its journey will not affect the redshift observation at receiver. Not in my model, nor anyone else's.
What those points of mass are doing with respect to each other will however affect the magnitude of the gravity field between 'all of' the masses.

Can I please ask if you understand that an almost uniform sea of particles/energy will divide under the influence of gravity into clumps of mass and tracts of open space anisotropic gravity field?

[alancalverd]

We haven't got to the question of whether the universe is expanding, contracting or clumping. Until you understand the mechanisms of redshift, which is the principal observable of distant objects, you won't be able to propose an experimental test of any model.

But your latest reply to Colin suggests that you do understand it, so your model has to explain why more distant objects generally have larger redshifts, without referring to the irrelevant stuff between the source and the receiver. Let's try:

If a galaxy contracts towards its barycentre at a fixed distance from the observer, the observed gravitational redshift will increase with time. This is indeed observed but clumping can only be inferred and the "fixed distance" is highly unlikely. What else do we know?

Suppose our target galaxy is at distance 2n light years. If its gravitational redshift is increasing with time, an observer at n lightyears will see a more recent and therefore larger redshift than we do. We don't have the luxury of making such observations, but we do have plenty of objects at different distances, and a fixed local gravitational potential against which to measure them. Unfortunately it turns out that the nearer objects have smaller redshifts.

So if the distant galaxy is clumping, we need to add a receding Doppler component larger than the rate of increase in gravitational redshift to account for the observed general increase in redshift with distance.

In short, the observations suggest that local clumping is only consistent with an expanding universe.

Can we have local contraction and distant expansion? Yes, of course. Local condensation is what makes planets,  solar systems and even shrinking galaxies and colliding stars. But if there is more matter outside the observable universe, stuff further away from us will have both a local (clumping) and a general (expanding) motion. No new physics, just a realisation that the observable universe the observable portion of the universe, and just as Hawking radiation gives us a clue to the content of a black hole, so the Doppler shift of distant galaxies gives us an idea of how much stuff we can't see.

[timey (OP)]

I do not understand why you think that light that is arriving from further away will have a lesser redshift than a nearer source.
A more distant object will have a greater redshift than a closer object, this being b/c the light has spent a longer time in the field than the light from the nearer object has.  If the light has spent more time in a weakening field, the redshift will be greater.

Edit: I do agree that your hypothesis is interesting, but it is not testable.  My contracting model is.

[Colin2B]

As Alan says the following post indicates you understand what we are saying

@Colin2B. I already stated 10 times now that points of mass that the light moves past along its journey will not affect the redshift observation at receiver. Not in my model, nor anyone else's.

But this one indicates you have a different interpretation of the field.

What those points of mass are doing with respect to each other will however affect the magnitude of the gravity field between 'all of' the masses.

If light passes through our solar system we are agreed that passing through that field will not affect the shift of the light. However, at any point the magnitude of field it passes through is the sum of all the influences from all the bodies in the system. So it is no different to the case you are stating.

However, i think this is the real sticking point.

A more distant object will have a greater redshift than a closer object, this being b/c the light has spent a longer time in the field than the light from the nearer object has.  If the light has spent more time in a weakening field, the redshift will be greater.

You are thinking big field changing while light goes from one end to other. What Alan is saying is that as it moves from one infinitesimal point to another it is still only moving from one gp to another and so the intervening field variation has no effect.

[timey (OP)]

But, unless the universe is expanding of course, this means that you cannot calculate grav.source minus grav.receiver to calculate the entire amount of gravitational shift in the field.  There are other bodies of mass affecting the field.

[alancalverd]

I give up.

[timey (OP)]

Ok - so Christof Wetterich's model differs from mine in many respects, but in this thinking below, he and I are on very similar ground. (marked with ***)

quote
"Wetterich's idea is that light emitted from an atom is governed by the mass of its particles—if that atom were to become larger in mass, the light that it emits would change in frequency as its electrons became more energetic. More energy would appear as light moving toward the blue spectrum, while less energy (an atom losing mass), would move toward the red spectrum. ***Thus, Wetterich reasons, if the mass of observable objects were once less, we would now see them with a redshift as they expand. If his line of reasoning is true, Wetterich says it's possible that the universe is actually contracting***."

Read more at: https://phys.org/news/2013-08-cosmologist-universe.html#jCp

[alancalverd]

Unfortunately, Wetterich's theory can't be tested because of the relative nature of mass. Everything we are able to see has a mass that is relative in size to everything else. Thus if it's all growing, we wouldn't have anything to measure it against to see that it's happening.

Wrong.

1. F = Gm₁m₂/r², so if either or both m is increasing, a Cavendish experiment or spring gravimeter will demonstrate an increase in F. No evidence to date, though you might need to wait a long time to see it.

2. If the mass of the receiver is increasing with time, then the light from distant objects will be increasingly blueshifted with distance. Counterfactual - and we have been observing for around 13 billion years..

[timey (OP)]

Correct. (I too find Wetterich's reasoning flawed) But I note that he has, in his paper, managed to make a mathematical description despite the wrongness you mention, and that is Wetterich's model.

But ditching the idea of an atom size becoming bigger with time, if the galaxies of galaxy clusters get closer together over time, then in a universe that is 'contracting' under the influence of gravity, an observation of light from a distant galaxy cluster will be redshifted, and light arriving from more distant galaxy clusters will be further redshifted, b/c that light was emitted at a point in history that pre-dates the light emitted from the closer galaxy.

So (again) looking at 2 adjacent galaxy clusters that are both converging upon their barycentres, we have 2 separate areas of multiple masses that are becoming more gravitationally concentrated, and the tract of space between them will be becoming more gravitationally diffuse.  This will cause a redshift.
If Wetterich can mathematically describe his model, I see no reason why my model cannot be described mathematically...
...And, unlike Wetterich, my model 'can' be tested.  To say so, none of the other toe models, string theory, loop quantum gravity, holographic, etc, can be tested either.  Surely the fact that I provide a testable prediction counts for something? Doesn't it?

[alancalverd]

You need to make up your mind as to whether decreasing a gravitational field increases or decreases redshift. It is difficult to convince you that it does neither whilst you believe it does both. Physics is not religion!

in a universe that is 'contracting' under the influence of gravity, an observation of light from a distant galaxy cluster will be redshifted, and light arriving from more distant galaxy clusters will be further redshifted, b/c that light was emitted at a point in history that pre-dates the light emitted from the closer galaxy.

I explained why this was exactly wrong a few posts ago.