I am about to deal with a subject in which I am a literate non-expert. I invite credentialed physicists to correct anything that I might have misunderstood or omitted.
As @PdotdQ mentions, they are dealing with real data points emerging from an extremely high-energy regime that is not yet fully understood.
The thing you have not mentioned is that the regime where c and the fine-structure constant might not have been truly constant ended very early in history of the universe. Consider this analysis by Tom Roberts, a UC-Riverside physics prof:
The Constancy of Physical Constants
- Tubbs and Wolfe, “Evidence for large-Scale Uniformity of Physical Laws”, Ap. J. 236 (1980), pg L105.Uniformity to 1 part in 104 is shown, subsequent to an epoch corresponding to less than 5% of the current age of the universe.
- Potekhin and Varshalovich, “Non-Variability of the Fine-Structure Constant over cosmological Time Scales”, Astron. Astrophys. Suppl. Ser. 104 (1994), pg 89.Quasar spectra with redshifts z ~0.2–3.7 are used to put a limit on the rate of change of alpha of about 4 x10−14 per year.
This is why your appeals to “zippy light” and neo-Lorentzian ideas do not make any sense. You are appealing to hypotheses that might possibly apply to an era that ended over 13B years ago. As the results from Tubbs, Wolfe, Potekhin, and Varshalovich show, these hypotheses have no applicability whatsoever to the question of how long it takes for light from the Andromeda Galaxy to reach us today.
I am reminded of YEC geologists who cite the acceleration of radioactive decay under “laboratory conditions” in an attempt to undermine radiometric dating. However, the laboratory condition was a tiny mass of plasma heated far above the temperature of the surface of the sun. If you are appealing to a condition that requires the entire earth to be heated to a temperature far higher than the surface of the sun, you are clearly outside any reasonable scientific framework.
The burden of proof is on you, @stcordova, to show how “zippy light” could possibly exist in most recent 95% of the universe’s history. The speculation that it might have existed for a short period over 13B years ago does not help you in the least.
Roberts’ analysis of experiments that purport to show violations of special relativity (SR), general relativity (GR), and physics constants is also quite illuminating:
10. Experiments that Apparently are NOT Consistent with SR/GR
It is clear that most if not all of these experiments have difficulties that are unrelated to SR. In some cases the anomalous experiment has been carefully repeated and been shown to be in error (e.g. Miller, Kantor, Munera); in others the experimental result is so outrageous that any serious attempt to reproduce it is unlikely (e.g. Esclangon); in still other cases there are great uncertainties and/or unknowns involved (e.g. Marinov, Silvertooth, Munera, Cahill, Mirabel), and some are based on major conceptual errors (e.g. Marinov, Thimm, Silvertooth). In any case, at present no reproducible and generally accepted experiment is inconsistent with SR, within its domain of applicability. In the case of some anomalous experiments there is an aspect of this being a self-fulfilling prophecy (being inconsistent with SR may be considered to be an indication that the experiment is not acceptable). Note also that few if any standard references or textbooks even mention the possibility that some experiments might be inconsistent with SR, and there are also aspects of publication bias in the literature—many of these papers appear in obscure journals. Many of these papers exhibit various levels of incompetence, which explains their authors’ difficulty in being published in mainstream peer-reviewed physics journals; the presence of major peer-reviewed journals here shows it is not impossible for a competently performed anomalous experiment to get published in them.
There is a common thread among most of these experiments: the experimenters make no attempt to measure and quantify the systematic effects that could affect or mimic the signal they claim to observe. And none of them perform a comprehensive error analysis, which is necessary for any experiment to be believable today— especially ones that purport to overturn the foundations of modern physics. For Esclangon and Miller this is understandable, as during their lifetimes the use of error bars and quantitative error analyses was not the norm; the modern authors have no such excuse. In several cases (Esclangon, Miller, Marinov, Torr and Kolen, Cahill) it is possible to perform an error analysis which shows that the experiment is not inconsistent with SR after all.
Another common thread among many of these experiments is the claim of “agreement with Miller’s result” (Kantor, Marinov, Silvertooth, Torr and Kolen, Munera, Cahill). Miller was the first to claim to have measured the “absolute motion of the Earth”, and his result has achieved a sort of “cult status” among people who doubt the validity of SR. The paper referenced below in the discussion of Miller’s results shows conclusively that his result is wrong, and explains why in detail. So claims of “agreement with Miller” generate doubts about the validity of experiments making such claims (how likely is it that a valid result would “agree” with a demonstrably bogus result?).
A key point is: if one is performing an experiment and claiming that it completely overthrows the foundations of modern physics, one must make it bulletproof or it will not be believed or accepted. At a minimum this means that a comprehensive error analysis must be included, direct measurements of important systematic errors must be performed, and whatever “signal” is found must be statistically significant. None of these experiments come anywhere close to making a convincing case that they are valid and refute SR. This is based on a basic and elementary analysis of the experimenters’ technique, not on the mere fact that they disagree with the predictions of SR. Most of these experiments are shown to be invalid (or at least not inconsistent with SR) by a simple application of the elementary error analysis or other arguments relating to error bars, showing how important that is to the believability of a result—the authors merely found patterns:
Amateurs look for patterns, professionals look at error bars.
All that being said, I repeat: as of this writing there are no reproducible and generally accepted experiments that are inconsistent with SR, within its domain of applicability.
Best,
Chris Falter