For those having trouble with understanding the complexity of the physics described above in my post  here is a simple "laymans explanation" (from some of my former posts here) that might help simplify it.
Quote:
"The speed of light cannot be infinite since it is quite simply measurable" (attributed to Eirie Engineer member)
The above statement (as usual with EE, zero supporting explanation or attempt at proof) suggests that Mitchellson Morleys LINEAR light speed experiment results, upon which Einstein built his proof for e=mc^2, were correct.
As the original poster of this thread so eloquently pointed out, the entire experimental design was flawed from the outset. (Note that my proof is mathematically correct also).
Clearly the intention with the MM linear light speed experiment was originally designed to determine the effect of any of the passage of light thru the ether of space was constant and whether the direction of spin of the earth had any effect upon the measured velocity of light in the vacuum of near earth space.
Experimentally sending one light beam in the direction of the earths spin and one against the direction of the earths spin, the exact same distance to an interferometer  should have proven or disproven this theory!.
The experimental design error was that after splitting the beam of light thru a 50% silvered angled mirror, to get two beams of light and sending one beam in a measured direction with the direction of spin of the earth and one against the direction of the spin of the earth to try and measure any effect of the earths rotation thru the ether of space, the experimenters Mitchellson Morely made the fatal design error, of then reversing the direction of travel of each of the two beams of light off 100% silvered mirrors directly BACK against the direction they were sent  effectively balancing out any increase in speed for the direction with the earths spin and conversely also balancing out the direction against the earths spin for each beam of light before them measuring their velocity over distance at the interferometer.
By doubling the light beam back on itself effectively reversing ts direction against or with the earths direction of spin  there was no observable difference in the measured velocity of the two light beams & the incorrect assumption was then made that there was no ether of space and that the speed of light must be constant and the measured velocity of 186,000 miles per second or 3 x 10^8 meters per second.
This error in turn lead to Einstens error with e = mc^2 where he ignores totally the negative root speed of light which when squared gives the same result as the positive root speed of light squared  because a negative squared yields a positive outcome.
In Essence what Einstens equation wrongly asserts is this:
That a positive photon of light traveling East at 3 x 10^8 meters per second, can also at the exact same time  be a negative photon of light traveling West at the same 3 x 10^8 meters per second!.
This is a clearly paradoxical outcome (how can the same photon of light be traveling in tow opposite directions at the same time at the same speed? suggesting a false premise to start with!
In Einsteins E=MC^2 case the paradox was known as the twin paradox and even Einsten himself acknowledged his error before his death.
Suggesting that a single photon of light can perform that neat trick of traveling in two completely opposite directions, at the same time, is akin to suggesting that;
If All dogs have 4 legs
&
All 4 legged animals are Cats
Then
All dogs are cats
& all cats are dogs!
Clearly a paradoxical outcome (from starting with the false premise number 2 that "all 4 legged animals are cats") is the only possible outcome of cmmencing with a false premise and that's what Einsteins E=MC^2 by his own admission with "the twin paradox" (google it) proves!
Just as Mitchellson Morleys experiment was deficient in design to prove or disprove the existence of an ether.
There is only one possible velocity for the speed of light that would make e=MC^2 correct mathematically and that is infinity  because infinity squared is infinity.
Also if the velocity of light is infinite  then could not a single photon of light travel both East & West at the exact same time & speed  since if its velocity is infinite  then it can travel positive East or negative West (infinitely large or infinitely small) at the same time  because it is infinite after all!
Paradox solved.
There is only one possible speed/velocity for light and that is infinite.
Let me give you a 2 dimensional "similie" for you to be able to understand the above clearly and see the big picture here.
The Mm experiment was designed to ether prove or disprove the existence of space ether which it did not do due to the described experimental design flaw at the outset.
Assume for just a few moments that MM were wrong and there is a space ether.
Lets imagine that ether is the ocean that surrounds our planet.
Floating in that Ocean (ether) is a boat called appropriately enough "photon of light"
The boat called "photon of light" is making way in the ocean in a westerly direction at a velocity of 10 knots to make it easy! The velocity of vessel "photon of light" then is westerly at 10 knots!
Imagine now if you will.
The same vessel "photon of light"  traveling in a westerly direction at the velocity of 10 knots, encounters a strong tidall influence of the water in that ocean (Space ether) traveling EAST at a rate of 20 knots!
Here we have... a single "photon of light" (vessel), making way thru the ether (ocean) in a westerly direction, at the same time that the ocean water (ether) is traveling itself because of tide in a Easterly direction at 20 knots!
The net "speed over ground" of vessel "photon of light" is at the same time it is making way at 10 knots Westerly is actually minus 10 knots Easterly!
Thus a single vessel "photon of light" is traveling both West (positive) at 10 knots and also east (negative) at 10 knots AT THE EXACT SAME TIME!
Thus also  the speed of vessel "photon of light depends entirely what velocity the vessel has on due to her engine pushing her  plus (or minus) the velocity & direction due to tide of the ocean (ether) thru which the vessel "photon of light" is passing!
When the vessel..."photon of light" travels with the tide, it adds to its velocity and when it travels against the tide it subtracts from its velocity.
The vessel might always be capable flat out of say a theoretical still water velocity of 50 or 100 knots  but speed over ground will always vary with the tide of the ocean as to what its measured velocity over ground will be  dependent on the velocity of the tide and it's direction.
So it is with the speed of light and the ether of space!
Indeed this is what we observe with red phase shifting of light from distant galaxies  where currently scientists and physicists are at a loss to explain this red phase shifting of light from distant galaxies. Some have suggested that "the photons get tired after such along trip!"
The reality is that it depends what space ether currents the light wave encounters on its trips thru galaxies and past planets etc as to what wavelength it is phase shifted toward when it arrives  just as a ship in the ocean is affected by the forces of wind and tide as to the course and speed it attains and thus the duration of its journey from point A to point B.
Imagine if you will that, the ether of space is like say molasses, ad any planet that spins about its own axis as Earth does  drags along with it a "space blanket" if you will, of near earth space  that orbits along with the earth about its axis at the same rotational velocity but that the effect reduces the further away from earth you travel...
I find this a useful way to describe the phenomena of space ether and speed of light  most people can imagine a boat/ship in the ocean and the effect of tides and wind on a vessels course and speed thru the water and also over ground and this the infinitely variable duration of the journey.
So it is with photons of light in space.
Our experience with vessels in the ocean, should have been all Einstein and Mitchellson / Morley needed to know they were wrong with a constant speed of light, and e=MC^2
Its not so difficult when you think it thru to a logical conclusion really!.
The speed of light is thus truly infinite  both mathematically and logically!
It is the ONLY answer that actually works.
For all intents and purposes, the speed of light in near earth space, where the ether of space travels at a velocity approximating that of the earth in its spin about it's own axis and the same orbital velocity of the earth about the sun, the speed of light seems to approximate 186,000 miles per second, or 3 x 10^8 meters per second  making MM and Einsteins work "seem correct" in near earth space! Our experience with probes now traveling outside our solar system and phase shifted light from distant galaxies however seems to suggest that in the wider universe the speed of light is truly & definitely infinite and a function of the relativistic velocity of the space ether thru which it travels.!
Clear as mud to anyone with a logical brain!
P.s. EE, your claims would be far more believable, if you supported them with even a hint of logic.
PP.s  Far from a cut n paste job that was all my own work straight off the top of my head so no doubt some here with the attention span of a gnat will be seeking the cliff notes as they never learned to read or compose anything longer than a text message!

Maybe that helps simplify it to the 2 dimensional "boat thru water" simile.
Cheers!