(February 24, 2015 at 11:40 am)Alex K Wrote:(February 24, 2015 at 11:34 am)AFTT47 Wrote: I don't get it. As has been pointed out several times, gravity does deflect the path a photon. It has been observed. I believe that was the first test of general relativity. A star was observed close to the sun during a total eclipse and its apparent position was indeed shifted by the sun's gravity well.
As I understand the OP now, the question would then be whether the way in which matter/spacetime deflects the photon isn't also determined from the start because the proper time of the photon is zero.
No because it's still relative to the observer not the photon itself.
The OP seems to be predicated on the observer buying into the photon's self-referencing spacetime rather than it being observed through the observer's spacetime (relatively). Any deflection, therefore, is a relativistic observation. The proper spacetime of the photon itself is an irrelevance.
MM
"The greatest deception men suffer is from their own opinions" - Leonardo da Vinci
"I think I use the term “radical” rather loosely, just for emphasis. If you describe yourself as “atheist,” some people will say, “Don’t you mean ‘agnostic’?” I have to reply that I really do mean atheist, I really do not believe that there is a god; in fact, I am convinced that there is not a god (a subtle difference). I see not a shred of evidence to suggest that there is one ... etc., etc. It’s easier to say that I am a radical atheist, just to signal that I really mean it, have thought about it a great deal, and that it’s an opinion I hold seriously." - Douglas Adams (and I echo the sentiment)
"I think I use the term “radical” rather loosely, just for emphasis. If you describe yourself as “atheist,” some people will say, “Don’t you mean ‘agnostic’?” I have to reply that I really do mean atheist, I really do not believe that there is a god; in fact, I am convinced that there is not a god (a subtle difference). I see not a shred of evidence to suggest that there is one ... etc., etc. It’s easier to say that I am a radical atheist, just to signal that I really mean it, have thought about it a great deal, and that it’s an opinion I hold seriously." - Douglas Adams (and I echo the sentiment)
