Originally Posted by JimJast

I'm guessing that this last one was directed to me. If yes, then I'd like to explain what the real supposition is (so you don't need to guess):

The supposition is not that photons can lose energy without any contact with anything (I think that Einstein's theory, that I assume true, prevents them from this). However they should lose energy from point of view of Newtonian physics through so called "gravitational interaction" that in astronomy is known as dynamical friction. Since in Newtonian physics we have strict conservation of enrgy, it has to be reflected by the redshift of those photons (despite that the real mechanism of the redshift is different than what Newtonian physics assumes, since real physics is not Newtonian but Einsteinian).

Now, the amount of dynamical friction of photons is not known since (I assume) it was never calculated outside the Newtonian physics and the Newtonian physics doesn't apply to photons, but "gravitational interaction" obviously does apply to photons. So we have a small discrapancy in energy of photons from point of view of any physics (either Newtonian or Einsteinian), which is somehow swept under the carpet in saying that it is "negligible" so presumably we may forget about it.

I didn't forget about it and calculated the redshift being the relativistic counterpart of the loss of energy of photons myself, and it came very close to the Hubble redshift. So at least it is not "negligible" and if we treat physics seriously then the Huble constant should be adjusted for this value.

Unfortunately then the expansion would disappear and it may pose certain problem to the Big Bang Theorists. That's why I'd like to discuss with them this issue and also maybe that's why they try to avoid discussing it with me (for lack of time as they claim). For over 20 years by now. Since I don't believe in conspiracy theories where something may be adequately explained by stupidity I don't suspect a conspiracy (explanation for those who have a custom of jumping to conclusions).

In the meantime it turned out that the dynamical friction of photons is a purely relativistic effect and it is inversly proportional to the radius of curvature of space (in first approximation the redshift Z=r/R, where r is distance the light travels and R is radius of curvature of space, which makes Hubble constant H_o=c/R, where c is speed of light, a very convenient device for calculating the radius of curvature of space, and so also the space density, once one admits though that the big Bang was a mistake, which I doubt could happen).

So my question is not what happens to energy of photons, but how astronomers explain the mechanism that allows them to ignore the redshift being the relativistic counterpart of the Newtonian loss of energy of photons (however tiny it is). I was told that by assuming validity of only the conservation of 4-momentum and not energy and momentum separately. It creates a problem of conversion of momentum into energy that anyone who understands the issue should be able to answer. I just want straight answers to straight questions, nothing outragious.