AS we all know, the speed of light is constant wherever and whenever you observe it. Nevertheless, how could that happen? In the first place, why could the light travel. in other words, how could light travel from one place to another? secondly, why the speed of light keep constant, to put in another way, why the speed of light never slow down? Furthermore, if I could travel at the speed of light will I never die? Or could I become younger if I can travel with the speed great than the light? Finally, if I could travel with the speed great than the light, Could I change the history or see the light from the past?