Chroot: "who don't actually even understand the theory, are so content to call it wrong. " Im beggining to think you know very little about this subject as well. You seem only to insult people, instead of actually DISCUSSING the material. If we don't understand it, why don't you explain it them. "That's not a very fundamental definition" You seem to think in absolutes. That may not be YOUR definition, BUT it WAS how i WAS using the word. If I used the word carrot to mean gravity, you should be able to understand it after i give you MY definition for it. "all derivatives of position are important, if you insist on looking at things that way. " I understand the mathmatic theorys are considerably accurate. Is there a mathmatical calculation to find a sum of infinte derivatives? "If you move further away from the sun, the light will take longer to get to you, since it has further to go and it must go the greater distance at the same speed. " I love how you treat me like I am mentally slow. I DO think that is how things work, but I was under the asumption that relativity thought differently. If light always travels at the same speed for all frames of reference, then consider this example: Two observers are both 100 light-seconds away from a light source. The light source pulses. At 50 seconds after the light left the source, observer MOVE starts moving away from the source at .01 c, while the other observer, STAY, stays in place. You said "the light will take longer to get to you, since it has further to go", therfore the moving observer should see the light after the stationary observer. LS = Light-second D([bserver]= distance of observer from light pulse SC([observer]) = Speed of light (derived) relative to observer at time 0 s - D(STAY) = 100 LS D(MOVE) = 100 LS at time 50 s - D(STAY) = 50 LS D(MOVE) = 100 LS at time 70 s - D(STAY) = 30 LS D(MOVE) = 30 + 20*.01c = 100.2 LS at time 100 s - D(STAY) = 0 LS D(MOVE) = 0 + 50*.01c = 100.5 LS at time 100'000/995 ~ 100.5025 D(MOVE) = 0 Average Speed = d/t SC(STAY) = (100-0)/100 * c = 100/100 * c = 1 * c = c SC(MOVE) = (100-0)/(100'000/995) = 995/1000 ~ .995 c As you can see, with the asumption that light takes a longer time to travel to an oberver who had started to move away from it, you can not also make the assumption that light has the same speed for all observers. This is because the distance between the light and the observers was ALWAYS less than 100 meaning that the fact that one observer moved makes the light travel slower, not the overall distance increase. Rav: "In other words, everything is always travelling through space-time at the speed of light. " Ok, that is actually a very intuitive way to put it, thanks. Prosoothus: "relativists also believe that the time dilation a moving observer experiences is dependent on the direction the particles of light are moving relative to the observer. " I haven't heard that particular hypothesis before. How would this work, do you know?