Once again, it seems communication is being impeded by the absence of mutual understanding of key terms.

Let's start with a summary of the standard meaning of a set of key terms.

In modern astronomy, astrophysics, and cosmology, the observed redshifts of objects are attributed to some combination of three different mechanisms:

- relative motion along the line of sight; this is the classical "Doppler effect", and dominates the observed redshifts of objects within the Local Group of galaxies, whether they be the Moon, the Cassini spacecraft, Barnard's star, the star S2 near SgrA*, hot shocked gas in supernova remnants in our Milky Way (and the Magellanic Clouds, M33 (etc)), or CO molecules in M31 (and much more). It is also an important component in the line spectrum of all galaxies, arising from rotation (e.g. in spirals), integrated motion (e.g. in elliptical galaxies; line broadening in this case), or relative motion within galaxy groups or clusters. And so on. In the case of galaxies within groups and clusters, the relative motions of the galaxies within those groups and clusters is (sometimes, often) called 'peculiar redshift', to distinguish it from the cosmological redshift (see below).

- gravitational redshift; this is a quite minor component and is observed only in a small number of highly dense objects, such as white dwarfs, and accretion disks around (SM)BHs (supermassive black holes). The physics underlying this kind of redshift is that described by GR, and tested to very high precision in a series of 'lab' experiments that date back nearly half a century now.

- cosmological redshift, or 'the expansion of space'. Like the previous kind of redshift, the underlying physics is also GR ... but applied to the whole universe this time. Historically and observationally this is 'the Hubble relation(ship)' - an almost linear relationship between the observed (integrated, central) redshift of galaxies and their distances; the constant (slope of the line) is H₀, the Hubble constant, the 'present' value of the (local) rate of expansion of the universe.

Your re-statement of the ATM idea being presented here (in post #56) introduces the term 'spatial redshift'. From the context it seems this is a term of critical importance to your idea. However, it is not defined. Further, it is not a standard term used in modern astrophysics or cosmology.

Can you please provide a clear, detailed definition of 'spatial redshift'?

In the part of your post that I quote above, and elsewhere, you use the term 'gravitational redshift'. From the context of your uses of that term, it seems (to me) that this is at least somewhat different from the standard, textbook physics term; it seems to have a meaning something like 'the redshift that arises from a mechanism that is called 'gravitation' in the ATM idea presented in this thread.'. However, as this term is used in close proximity to another term (Doppler redshift), which term does seem to be used with its normal, textbook meaning, I can't be sure.

Can you clarify please?

Specifically, please state - as clearly and unambiguously as you can - just which terms you intend to use with the standard, textbook definitions, and which have definitions that are peculiar to the ATM idea you are presenting in this thread.I understand very little of this.

However, it seems that your idea of the nature of electromagnetic radiation (EMR) and of photons is at least significantly different than either classical electromagnetism or quantum theory.

Within the ATM idea you are presenting in this thread, to what extent do you (exclusively) use either classical electromagnetism or the quantum nature of 'light' ('photons')?

To what extent does your ATM idea require (entirely) new physics wrt EMR or photons?I'm confused.

On the one hand, you have declared that the ATM idea you are presenting in this thread has been developed in a logical fashion only, and, specifically, "[n]o formula is available for summing up the ongoing influence and realizing that gravitational redshift is a function of distance."

If we have neither formulae nor OOM (order of magnitude) estimates, then surely we have no way of assessing how long 'long distances' are? I mean, they could be as long as 10¹⁰⁰ Mpc, or as short as 1 nm!

Similarly 'small' could be within the scope of 17th century physics lab instruments to measure, or 10¹⁰⁰ times smaller than the best we can do today!

The same with 'slower'.

And so on.

But perhaps I'm missing something ... perhaps, even with just logic alone it might be possible to test your ATM idea?Note that the logic of this part of your response seems to be: "the standard explanation is wrong, THEREFORE my idea MUST be right!"

As I'm sure you did not intend to use such logic, I will ignore this part and focus on the next part.I want to be crystal clear on this: are you prepared to answer questions on, and address challenges to, "Halton Arp’s findings of the location of quasars"?

Note, for avoidance of doubt, that these so-called findings are most certainly against the mainstream! Putting them on the table thus means they are within the scope of the BAUT rules and policies on ATM ideas.I want to be crystal clear on this: are you prepared to answer questions on, and address challenges to, "10 and then 30 issues presented by Tom VanFlandern at Meta Research"?

Note, for avoidance of doubt, that these so-called issues are most certainly against the mainstream! Putting them on the table thus means they are within the scope of the BAUT rules and policies on ATM ideas.Thanks for the clarification; let's have no more mention of it in this thread, shall we?