Measuring the One-Way Speed of Light: Special Relativity, and "Test Theories"

[Aether]

Declared by whom? By you, "Aether"?

The declaration is by unanimous consent.

I contacted them and asked them to log in directly into the website such there is no cheating.

Ok, great. It will be an honor to have them participating in our discussion.

Feel free to contact them as well but no direct mail to you will be trusted.

This is why I suggested that it should be you who makes the initial contact with them.

[clj4]

The declaration is by unanimous consent.

Meaning you and gregory?

Ok, great. It will be an honor to have them participating in our discussion.

This is why I suggested that it should be you who makes the initial contact with them.

Ok, I made it, now let' s wait and see.

[The Bad Astronomer]

"Socky"
Try using a civil tone. If you have servants at home, then try remembering that I am not part of your servant crew.

You need a lesson in civilized behavior.

clj4 has repeatedly ignored warnings about uncivil behavior here on this board, and this was the last straw. Behavior like this will not be tolerated. He has been permanently banned from BAUT.

[Gregory9]

Well, since clj4 was the only one maintaining the against mainstream view, I guess this is done now. (Unless of course the professors that clj4 emailed choose to come and give a summary for us. That would be very nice as well.) Until then, here is what I feel the summary is:


- Most (if not all) of physics can be written with tensor notation. For example, Maxwell's equations, the Lorentz force law, even GR.

- Because of this, we can choose to do physics in ANY coordinate system as long as we do all the transformations correctly.

- One paper that clj4 references is
D.R. Gagnon et al., Guided-wave measurement of the one-way speed of light, Physical Review 38A(4), 1767 (1988)
These authors define some "special frame" and then do transformations to other coordinate systems using either Lorentz transformations, or a type of "Generalized Galilean transformations". They start with maxwell's equations in tensor notation, do the transformations, and somehow conclude that they can experimentally differentiate between these two coordinate systems ... even though the phyiscs is still represented by the same tensor equations.

- This paper is clearly wrong (and even clj4 admits they made many mistakes). Incorrect papers do get published from time to time. I have even taken the time to work out the equations for that paper and show the correct result as well as suggest where their error may have creeped in. If the tensor equations are correct, then we can use any coordinate system we choose. Mainstream physics does not believe there are only some select "real" coordinate systems of the universe.

- The other papers and books clj4 references, actually support the standard view as we have tried to show to him time and again. Feel free to browse back through the thread if you are interested. Here's some quotes from the Zhang book http://www.bautforum.com/showpost.ph...&postcount=102.


How does this relate to "one way speed of light"? Velocity is inherently a coordinate system dependant quantity. However, there are things we CAN say about it in a coordinate independant way. For instance: does the speed of light depend on the velocity of the source? This can be asked in a coordinate independant way. Experiments have shown that the answer is no.

Not much else can be said in a coordinate independant way. Even if we restrict ourselves to inertial frames (defined for this purpose as frames in which a freely moving object has a constant velocity), we still have not restricted ourselves enough to say what the one way speed of light is.

What if we restrict it further by requiring one coordinate to be a "time coordinate" which refers to the time measured by stationary 'standard' clocks in that frame, and the remaining coordinates be "spatial coordinates" that agree on the length of a stationary 'standard' ruler (if it is accelerated or moved to make it at rest in the frame of question)? It turns out that this restricts us now to the lorentz transformations except for an ambiguity of the simultaneity definition.

If we restrict it even further and require that "empty space" appears isotropic (in the physical laws), then this is defining the one-way speed of light as isotropic. And yes, this restricts us to lorentz transformations.

This in no way means that we have found the "real" coordinate systems of the universe. Merely that physical laws (in flat space and inertial frames) transform simplier using some coordinant transformations. (Although one should not trivialize this fact, as it has led to very deep insights and many things come as a consequence of this: anti-matter, spin, "magneto" components of EM/gravity/and even QCD, and numerous other consequences.) However, we can still use any coordinate system to describe the universe.

(By the way, a mathematician may object and say we can use any coordinate system provided that it is "complete" ... ie every possible event location has a unique coordinate label (no "holes" in the coordinate system). I may have worded that badly, but we haven't been considering these perverse cases. So lets stick to discussing coordinate systems that are "complete" in that sense.)