Hi Robert.
Much food for though indeed. Mostly, in physics, answers are from such a different viewpoint to questions that no harmony results. I fear that here, but will first transmit on my own frequencies anyway. The conversation continued;
PJ; "I agree Albert, gravity is non zero in all inertial frames, but let's imagine ourselves 100 years in the future, and we find Galaxies have over 300Bn solar masses in their ion plasma Halo's, many kpc's deep at densities up to 10^9/cm^-3. And the Earth has a similar density plasmasphere. Do you think light could pass through these respectively at 'c' with respect to deep space, and at 'c' wrt the sun? Or would it change to the local 'c'."
AE; "Hmm, so you believe my friend Arthur is a bit of a duffer, light changes speed and curved space time is all about diffraction?"
PJ; "Well, let's just say you were right insisting Cartesian co-ordinates had to be attached to a body not used in the abstract, as there are no point particles, But the real point is that it proves your Equivalence of gravity and Inertial Mass, as particles, ions, can then condense from the ether increasingly with speed through it, representing the mass that attracts other particles."
AE "Mien Goot! That's so simple! Yes I did say space without ether was unthinkable! But! ..Will it pass the acid test?!"
PJ; "OK let's ask and find out. "Marleen.. have you got a sec to tidy the bar counter for an experiment?"
Marleen tidies the bar, PJ wets it, puts Albert at the other end and slides his beer along it at breakneck speed. Albert catches it.
PJ; "Now, ..Marlene, ..did the light going through the glass and beer take a different time to do it just because the bar was moving with respect to it, and the wavicles arrived at a faster rate?
Marleen "Of course not dumbkopft! did you never listen to Auguste the lighthouse keeper!?
AE; "Ahh' I see what you say! Unless we slide WITH the beer, light can appear to change speed both due to the 'n' of the beer AND the 'v' of the glass, so CAN be c/n plus v! Without Hendricks' exponentials, but still not actually break the 'c' limit! but of course!!, your beer is a galaxy!
PJ; "Yes, or just one moving electron. If only you could see 100 years into the future Albert, you'd probably still be brighter than most of them who may only be able to see 100 years into the past. And you were proved right, inertial mass really does = gravitational mass so a = g. I wonder if anyone in the future will have the intellect to see that!"
AE; "Ahh! but we won't be able to solve the problems of physics with the same kind of thinking that created them!"
PJ; "Who said that - Oh yes it was you, and perhaps your wisest words!. Another one for Albert please Marlene.."
If only! Peter