A lightphoton starts from origin O, at time t=0. At t=T, at point Q(X,0) it collids with the observer which came from point P(X,Y) in the same time with constant velocity. Seen from the frame of observer X remains the same, Y shrinks becomes Y/g(g=lorentz factor), time elongates, light has to travel OP in time t=Tg. So divide this new length by new time and you must get c back, but....?

Question

jamesj · Answer

What exactly is your question here?

binary3i · Answer

its special relativity, you dont get c the velocity of light

jamesj · Answer

I know it's special relativity.  Imagine a world diagram of this situation.  As far as the observer is concerned, the light particle left the origin later than the light particle 'thinks' it left the diagram.  In fact, it leaves the origin at exactly the time required so that from the observer's perspective, the speed of the photon remains c.