Sorry if I am asking the most stupid question but I am only an a-level student in the UK so don't have that a deep an understanding of physics. However my teacher says that the speed of light is always constant in a vacuum and this can be explained using curved space time and special relativity. I have no problem with this however. In another part of my course my teacher says that light travels as particles or photons. These photons can take an infinite number paths to get from A to B - however if the particles do not go in a straight line how do they go at a constant velocity? Surely the speed may appear to take longer if the path is a greater one that if the photon takes a more direct path. If you could explain this to me it would be appretiated.