nopeda, on 05 February 2013 - 11:50 PM, said:
No we sure don't, since we've never been far enough from this small area to have any idea what velocity light travels in different parts of the universe. At this point my impression is that we are in and have never been able to get out of and area where the velocity of light is "adjusted" by some thing(s) since all tests indicate that it always travels at the same velocity relative to THIS PARTICULAR PLANET. Most likely it's not this particular planet but this particular area, however large that area may happen to be. If light travels significantly faster outside of such an area it would explain why it appears that light from all sources impacts this area at the same velocity relative to the area but regardless of the velocity of the emitter relative to Earth/this area....
OK, but what would photons be doing in this region outside of our space? If dark matter or the fabric of space-time is indeed resistive, and controls the speed of light, then yes, I could see that as plausible, but not sure how or why our space would interact with this other type of space. To make sure I understand exactly what you propose, would it be something like a Photon travelling the expanse between theoretical multiverses? If that is the case, the the speed of light would also be dependant on that medium meaning the next Universe over could have a different speed of light to that which we have, probably based upon the most abundant matter created it this hypothetical "Other Universes" big Bang. We do not know the fabric of space time well enough to say if the Big Bang, or the most abundant element in the Universe has an impact on that. If it does, then yes, the speed of light would be considered a variable.
Or perhaps are you suggesting something like the fabric of space time having different densities in differing regions of space? That too, I admit might well have an effect on the speed of light. We have no reason to think so, but the idea seems plausible.
Edited by psyche101, 06 February 2013 - 03:47 AM.