The WHY of speed of light vs. the FACT thereof

[AdrianZ]

I don't suppose you could provide exact quotes from your book that make statements such as "Lorentz gave a wrong interpretation of his equations" or "experiments have proven SR correct and other theories incorrect" or "we can deny ether based on experiments"? Please?

I like what you said in your first post about Lorentz believing in æther while Einstein said there was no need to insist on the existence of æther. In other words, Lorentz felt the need to always pick a reference frame in which he was never at rest with respect to the æther so that MMX would experience length contraction and time dilation (because there was little chance that he could be at rest in the absolute æther frame) while Einstein said its OK to always assume that MMX is at rest in the absolute æther frame and everyone else that is moving are the ones that are experiencing length contraction and time dilation. It's that difference that made Einstein stand out from all the others and why he deserves all the credit for Special Relativity.

But you should acknowledge that if Special Relativity is an accurate description of reality, and that it affirms every inertial reference frame as being exactly like an absolute æther rest frame, then it certainly cannot be used to deny that an absolute æther rest frame could exist (but known only to Mother Nature).

according to the book I mentioned, Lorentz talked about length-contraction, not time dilation. if you claim Lorentz had come up with a consistent theory explaining time dilation and invariant light speed please provide resources verifying your claim.

I didn't say the existence of Aether can be denied, I said if we pose a theory based on the idea of Aether, we can do experiments to check the predictions of the theory and if it fails, the theory will be rejected. That's what we have done so far. what I meant was "all other theories based on the Idea of Aether before the SR had been rejected through experiments and Einstein's special theory of relativity was the only theory that successfully solved the contradictions between Maxwell's equations and Newtonian mechanics".

 

[Domenico Mico]

I appreciate the responses, although some are beyond my ken - IANAP. However, their net net still seems to be (1) it is because it is, and (2) that's the way the math requires it. For some reason, I don't have the same problem with time being flexible (two seemingly incongruent sides of the same coin?). It's all amusing as heck.

Hi, JoeShiner,
One more answer for you. This is how I see it. Once upon a time there was a monopole which, as Faraday wanted, generated an electric field which in turn generated a magnetic field which in turn etc... etc...
It appears that both of them at the starting line were full of energy and behaved like a bull at the gates with the end result that one second later, just before the end, we find them again, but this time they both are breathless. At the end of the run there it is: the surviving magnetic component is so tired that is unable to generate a further electric field and puts the final touch at the speed of light. The story ends, I think, with a somewhat undulating magnetic component joining, in its extremely weak conditions, his predecessors for the make-up of our expanding universe.

 

[harrylin]

what I claimed is based on the book "Introduction to Special Relativity" by Robert Resnick. if Lorentz had given a correct interpretation of the equations then the credit of the theory would've gone to him not Albert Einstein. the results of experiments like the Michelson-Morley experiment, the Fizeau experiment and many others leaded to the development of different theories like like the FitzGerald-Lorentz contraction theory, but all of those theories failed to justify later experiments. the only theory that has been proved right in all experiments so far is Einstein's special theory of relativity which is also mathematical consistent and can be simplified to Newtonian mechanics when v/c approaches zero.

about our inability of proving/disproving the existence of Aether, I think you are right. that's why I used "maybe" in my sentence. but we have many experiments against the idea of Aether, including the Michelson-Morley experiment. therefore we can't deny the possibility of an existing ether, but we can surely deny the theories developed based on the ether postulate through experiments.

Actually that is very inaccurate, as it's quite the opposite (but it's not your fault). Different book writers credited Einstein and Lorentz differently. And this is what Einstein admitted in 1907, discussing what then became known as the Lorentz-Einstein theory:

"We [...] assume that the clocks can be adjusted in such a way that
the propagation velocity of every light ray in vacuum - measured by
means of these clocks - becomes everywhere equal to a universal
constant c, provided that the coordinate system is not accelerated.
[..this] "principle of the constancy of the velocity of light," is at
least for a coordinate system in a certain state of motion [..] made
plausible by the confirmation through experiment of the Lorentz theory
[1895], which is based on the assumption of an ether that is
absolutely at rest".
- http://www.soso.ch/wissen/hist/SRT/E-1907.pdf

I will elaborate on that clarification by Einstein in a direct reply to the OP, as it is very helpful to understand the "WHY".

 

[harrylin]

I have puzzled over a couple of things relating to the speed of light as a constant to all observers. I fully recognize that it has been demonstrated to be so, and that those demonstrations have been confirmed by facts such as the existence and workability of GPS; however, these go much more to the FACT THAT the speed of light is a constant. I also recognize that, mathematically speaking (and I'm no math whiz), it MUST be a constant, since "somethin's got to give"; however, these do not satisfy my need to understand WHY the speed of light is a constant; or, put another way, HOW CAN IT BE that the speed is constant? I mean, everything else "gives" - the cars on the highway going toward one another or passing one another... and the trains, the planes, etc., but not light. HOW is it happening? Is light scrunching up or stretching out somehow as it needs to (but not as to speed [?!]), to the various and relevant observers?

As an aside - With reference to various experiments that have been conducted involving gravitational effects on time using atomic clocks aboard airplanes, if a quantum entanglement experiment was conducted involving photons that are "on" two different airplanes at two different gravitational states (and tied to atomic clocks, of course), what would be the result?

BTW, I am not a physicist and perhaps have no business at all sticking my nose in, but if some of you more well versed in these matters than I might take pity on me (and provide a bit of forgiveness of my ignorance, and benefit of the doubt, I'd be most appreciative). Thank you!

Hi Joe, several people have in part answered your question but if I did not overlook it, they forgot to mention clock synchronization.

First of all, in GPS the speed of your GPS receiver relative to a GPS radio signal is NOT constant, but exactly like you expect from cars and airplanes etc (in modern jargon, the closing velocity is c-v). In GPS, the Earth is a single system in which clocks everywhere are synchronized in agreement with each other.

What you probably can picture is Lorentz's model to explain light propagation. In that model, light is a wave in a medium and its speed is independent of the speed of the source. Moving objects in that medium slightly deform and clocks slightly slow down, but those are small effects that are not the main issue for replying your question that seems to focus on the one-way speed of light.

To measure the one-way speed, we have a light ray that propagates from one clock in the lab to another clock.

Funny enough, you can find any speed you like, depending on how you synchronize your clocks. In relativity, if you set up an independent measurement system then you typically use light or radio waves to synchronize your clocks; when you measure the same speed both ways, then you have synchronized your clocks!

Probably you can imagine that in a moving system, light takes longer in the forward direction than in the backward direction; and that by adjusting the clocks, you can make the measured speed equal in both directions. That speed would be very slightly less than c if the lab did not very slightly contract; those two effects exactly cancel.

With that explanation, light is not scrunching up or stretching out somehow, but objects are slightly affected; and the main explanation to your question is that clocks of independent systems are synchronized in such a way that the measured speed is again c.

I hope that this explains to you or some others "how it can be" that the speed that is measured in systems that move relative to each other, is constant.

Einstein clarified it as follows:

"We [...] assume that the clocks can be adjusted in such a way that
the propagation velocity of every light ray in vacuum - measured by
means of these clocks - becomes everywhere equal to a universal
constant c [..]
[this] "principle of the constancy of the velocity of light," is [..] made
plausible by the confirmation through experiment of the Lorentz theory
[1895], which is based on the assumption of an ether that is
absolutely at rest".
- http://www.soso.ch/wissen/hist/SRT/E-1907.pdf

And from my rather limited knowledge of quantum entanglement, the results should be independent of gravitational potential.