james@umcp-cs.UUCP (09/01/83)
I don't think it has been shown that there is only ONE speed of light. That is, the average speed of light (average of the north-bound and south-bound speeds) CAN be measured, but the speed of light in a single direction cannot be measured. It is possible that the speed of light is not the same in every direction, no one knows. --Jim
chongo@nsc.uucp (Curt Noll) (09/01/83)
i thought that Michaelson and Morley showed that the speed of light was constant in any direction by rotating their mirror system on a pool of Mercury and noting that there was no phase shift in the light. chongo /\../\
kalash@ucbcad.UUCP (09/02/83)
#R:umcp-cs:-230600:ucbcad:30300001:000:456 ucbcad!kalash Sep 1 12:57:00 1983 /***** ucbcad:net.physics / umcp-cs!james / 2:49 pm Aug 31, 1983*/ I don't think it has been shown that there is only ONE speed of light. That is, the average speed of light (average of the north-bound and south-bound speeds) CAN be measured, but the speed of light in a single direction cannot be measured. Greep? I thought one of the fundamental principles of relativity was that the speed of light is a constant in any medium... Joe Kalash
james@umcp-cs.UUCP (09/04/83)
Below, M-M stands for Michelson-Morley. Please allow me to clarify my statement in net.physics. First of all, I was using the terms north-bound and south-bound only because I felt that they might more simply convey the idea of opposite directions to a general audience. Second, I was not referring to the M-M experiment as it deals with aether. What I was stating is the possibility that the speed of light (in a vacuum) is not a constant for all directions. Because of the difficulty with the synchronization of two clocks separated by a distance, it is possible only to measure the time it takes for a light ray to travel in some loop. Therefore, the speed of light could be different in the positive-X-direction and the negative-X-direction, as long as the average were the currently observed single 'speed of light'. What the M-M experiment tells us is that the measured average speed of light in the X directions and the Y directions are the same. It may be possible to measure the speed of light in a SINGLE direction by arranging to have the light ray travel in a circular orbit about a large black hole (source of gravity sufficient to bend the ray), or by having the ray travel in a 'great circle' in space (which could possibly exist if space has the topology of a torus or some other topology permitting similar tricks). --Jim O'Toole