Is Lorentz factor reality true according to the laws of physics?? Hi According to the laws of physics, the speed of light is independent of the speed of its source. In the example whereby there are two observers; one in the train moving at high velocity u relative to the other observer on the platform. The one in the train light up a torch up at the top of the train and light reflect back to him. According to the other observer on the platform light seems to move up as well as forward and the down and forward back to the torch again. But is that what really happens, I mean if we imagine just a quanta of light will it really be affected by horizontal component of the train's velocity and if so isnt that actually tempering with the speed of light itself?? In my imagination, according to the observer in the train, light was supposed to be seen as if it was thrown up and back, bouncing on the train top and still moving back. On the other hand the observer on the platform was supposed to see light moving up and reflecting back down without any seemingly horizontal velocity components in it.