[Vern]

Why what?

The Friedmann equation already assumes that space-time is variable. It is useful in that context. We were questioning the assumption. How do we know that space-time is really variable. Observations that seem to show that it is can be explained by assuming it is the material things that vary.

[PhysBang]

Why what?

Why would a photon in the field you describe experience redshift?

The Friedmann equation already assumes that space-time is variable. It is useful in that context. We were questioning the assumption. How do we know that space-time is really variable. Observations that seem to show that it is can be explained by assuming it is the material things that vary.

Sure, you can assume that everything in the universe changes in such a way as to perfectly mimic a metric spacetime theory and everything in the universe, despite not being coordinated by a changing metric on spacetime, is nonetheless totally coordinated over all observable space in order to pull off this. And, for totally unrelated reasons, the background radiation just happens to produce measurements that match those we get from a metrical spacetime theory, even though there is no connection between those measurements and other measurements.

[Vern]

Why would a photon in the field you describe experience redshift?

Time experience is slower in gravity field. Light should experience a red shift. I guess I suspect that because something is needed to cause the time experience of matter to be slower.

I do not know how mainstream theory treats ambient gravity? I suspect that no one has really looked into it deeply. I have two unanswered questions. I'm searching for the answers.

Questions:
(1) Is there even such a thing as ambient gravity? For example, do opposing gravity fields simply cancel where the fields overlap, or is there a non-directional ambient gravity that still affects clocks and stuff in the field. I suspect that there is ambient gravity.

(2) Is time dilation experienced in a static gravity field? I think mainstream theory is that this is true. I suspect that experiment has already shown that this is true with the GPS satellites. I suspect that where there is time dilation there is also a gradual accumulative red shift. I suspect the arithmetic of GR can show this. But I have not seen it demonstrated.


It seems I remember that the amplitude of the CMBR radiation was first predicted to be on the order of 50 K and only became 3.5 K after it was measured. I also remember that Sir Arthur Eddington and a group of his collaborators predicted that the temperature of space should be about 4 K due to the warming of space debris by starlight.

From UCLA

[PhysBang]

It seems I remember that the amplitude of the CMBR radiation was first predicted to be on the order of 50 K and only became 3.5 K after it was measured. I also remember that Sir Arthur Eddington and a group of his collaborators predicted that the temperature of space should be about 4 K due to the warming of space debris by starlight.

From UCLA

You should take the time to read the page that picture comes from. It would clear up some of your misconceptions.

[Vern]

I did read the page. It was helpful.