I had some questions about how to understand the Minkowski diagram better: 1) One thing that I hear characterizes a light ray or a photon is that it "experiences no time." That is, it's time dilation is so extreme that at the "null lines" or light cone lines at the 45 degree mark, the photons, again, do not age or experience the progression of time (at least relative to the "lab frame"). However, if you look at the diagram, the photon (or light ray) is clearly moving through time and "aging." It just seems to be moving through space at the same rate it is moving through time. If the photon truly weren't aging, wouldn't it just be confined to the x-axis? This same argument, of course, applies to length contraction and in the exact same way. At the same 45 degree null lines, the length contraction is so extreme that the photon ostensibly has no size and "experiences no conception of space." However, is seems clear from the diagram that it is, indeed, moving through space as the null line has an increasingly (increasing) x-component value. So it seems I'm missing something here...Please do help explain what.