One Way Speed of Light

James, I don't quite buy Fransen's hypothesis. I think the light is simply delayed by the hot gas (or plasma) of the supernova. Neutrinos are not delayed by matter of any sort, AFAIK, so they arrive earlier. Gravitational 'wells' should Shapiro-delay photons and neutrinos equally, so I think Fransen takes a long shot. It will be interesting to watch the reaction in the scientific press, though...

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Regards

Jorrie

"Now if you send the signal from A , it will arrive at E at time tA+ the time needed for the light to travel from A to E."

KK, this is exactly the point: whatever the "real" one-way speed of light is, you will always get c, whether you use your method or Einstein's. Your method is just more complex and as far as I can see, gaining nothing for the trouble. Any anisotropy is still swept under the carpet...

Einstein pondered the same sort of thing and then had the insight to say: let's assume that the one-way speed is the same as the two-way speed and see where it takes us. It eventually took us to the full theory of relativity and nobody ever succeeded to poke a hole in the principle, except perhaps at quantum scales and cosmological scales, where it does not quite hold.

Various slow-transport clock experiments have told us that Einstein's was probably the right choice - nature seems to agree with him, at least over smallish distances (tens of kilometers). It does however not rule out that there may be an anisotropy in the propagation of light, even in 'free space'. In fact, because we know that space consists basically of gravitational fields, we expect there to be some degree of anisotropy - clocks cannot be synchronized all over space...

-J

Hi Jorrie,

Did you try to analyse the measurement of the speed of light using the proposed method?

If the speed of light was anisotropic like in my example, signal emitted at tA=tE=t0 from A would arrive at E at t0+4s, signal emitted from E at t0 would arrive at A at t0+12s and one way speed of light could be precisely measured.

GPS system succeeded in "poking a hole" in relativity theory showing that the speed of light can be c+v in one direction and c-v in the other. There is plenty of information on this on various websites.

Regards

KK

KK, there is nothing wrong with the calculations you made; they are just a round-about way to Einstein-synchronize your clocks A and D. With the 1 s and 3 s times that you gave, it implies that the proper (radar) separations between your points must be 2 light-seconds each.

Einstein would have sent a time-stamped light signal from C to A, to be reflected back, arriving 8 s later, irrespective of possible anisotropy. He would then have done it again and told A's operator to set her clock 4 s later than the time stamp she now receives. Ditto for E. This is the same result that you have obtained in post #88, i.e. clocks A, C and E are perfectly (Einstein) synchronized. Einstein would have done the same for clocks B and D and then all 5 clocks would have been perfectly synchronized, irrespective of any anisotropy.

Your method has done nothing more, just more cumbersome, I think...

"GPS system succeeded in "poking a hole" in relativity theory showing that the speed of light can be c+v in one direction and c-v in the other. There is plenty of information on this on various websites."

Such statements indicate a misunderstanding of relativity or of the GPS system (or both). There are plenty of that on the Web, I agree. In a 'trilogy' of Blog posts, I exposed one of the exponents of such statements a little. You do not have to take my word on it; I referred to some authoritative articles in the posts.

-J