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"faster than light" apparent movements can sometimes be observed in astronomy when the light "flash" from a supernova peak brightness passes through a layer of dust some distance away from the source of the flash.
"If you wave a flashlight across the night sky, then, in principle, its image can travel faster than light speed (since the beam of light is going from one part of the Universe to another part on the opposite side, which is, in principle, many light years away). The problem here is that no material object is actually moving faster than light. (Imagine that you are surrounded by a giant sphere one light year across. The image from the light beam will eventually hit the sphere one year later. This image that hits the sphere then races across the entire sphere within a matter of seconds, although the sphere is one light year across.) Just the image of the beam as it races across the night sky is moving faster than light, but there is no message, no net information, no material object that actually moves along this image."
PS: just been undergoing surgery so if my thoughts seem jumbled up, I will blame it on that
. . .assuming our standard interpretations of radiation being timeless etc. . .
you can assume that no matter what your frame of reference is, radiation will move at 'c' relative it.
Or alternatively build a case in where the only thing differing that sphere from the lights origin is the 'distance' that light has propagated. Gravity, etc, being the same. To me it becomes geometry, and assuming 'photons' existing, which they do, their 'paths' (relative each other that is:) if seen classically will widen.
As for a wave you then have the question of the energy received at the 'sphere'? by that waves motion laterally over each spot, as defined by the spots light detectors changing output? If you would find the energy to change with distance it would become a problem, ignoring expansion here. But if it doesn't change with the distance? Where would the extra energy needed come from? Always assuming a smooth motion of that beam laterally?
Sweet stuff JP. Although, heh, astronomically the definition of light or any radiation is that it has to be timeless, as I understands it? If you assume otherwise you get so called 'tired light'. But I'm guessing that you might say that as it 'propagate' (speed), according to what we observe and define, it also takes a 'time' according to us?
In the absence of proofs for a 'internal clock' I will consider it 'timeless' over those astronomic distances we've measured, ahem