Photon Speed Same Always?? Hi there. I read the following in a wikipedia article (http://en.wikipedia.org/wiki/Cherenkov_radiation): [Broken] Can anyone help me out to make sense out of this statement? The speed of a light wave [tex]v = c/n[/tex] in a medium is DIFFERENT that what it is in free space. Then how can the speed at which the photons travel be the same??