Robin van Spaandonk wrote: > In reply to Stephen A. Lawrence's message of Fri, 05 Sep 2008 17:29:00 -0400: > Hi, > [snip] >> They (apparently) oscillate, which, at least according to my limited and >> rather primitive understanding of relativity theory, means time passes >> for them, which suggests pretty strongly that their speed must be >> subluminal. At C, 1/gamma=0 and the particle must remain immutable >> between events, because its internal "clock" has stopped. > > This makes me wonder how an ordinary photon manages to go through umpteen > cycles > between source and destination with a "stopped clock". :)
It doesn't. A photon is the same no matter when you sample it. The wave function associated with it "goes through multiple cycles" (which are distributed in space) but the photon itself does not oscillate in any sense of the word. Remember, the photon is traveling with the wave front, and ON THE WAVE FRONT the E and B fields are "stationary". If, at the crest of the wave, E points up, then it's that up-pointing E vector which is traveling through space; at the crest it always points up, but the crest is moving at C. Any observer in any inertial frame will see an oscillating E field as the photon passes, of course, because the up-pointing E field at the crest is preceded and followed by down-pointing E fields -- but they're all moving along through space in tandem. If you could travel at C, and you flew along with a radio wave (which is easier to measure than a light wave), and you sampled the E and B fields, you would find that they didn't seem to be changing. This is one of the problems with traveling at C: In a frame of reference moving at C the traveling wave no longer looks like a solution to Maxwell's equations, because @E/@t = @B/@t = 0. The way out of this box chosen in special relativity is to let @t -> 0 when you travel at C. A "traveling wave" is exactly that. It is not a "changing wave"; rather it's a fixed pattern which travels through space. > > [snip] > Regards, > > Robin van Spaandonk <[EMAIL PROTECTED]> > >
