Hello all, First let me say that I have been battling with time dilation for years, all the videos seem to drive me more into confusion and reading does the same. The past few weeks I have been really trying to get a grasp on it better. I understand the concepts, theories, and postulates but I guess I am having trouble putting them into practice. So I created an example that I hope someone could look at. I recently discovered that GPS satellites have times adjusted due to SR and GR. Now GR I can understand and I think I have a safe understanding of. It is the special relativity that I have a hard time grasping. Ok here is my example: This is what I imagine mimics the GPS operation. 1) Person A (the ground observer) and Person B (the gps satellite) both have light clocks. Each clock allows light to bounce on plates (your regular light clock I suppose) 2) Person A and person B also have a device that is attached to their light clocks. This device registers each tick of a light clock. Upon that tick it drops a specific amount of water from a bottle (both person A and person B have bottles with the same amount of water. So tick, drop, tock drop. 3) Person A sets his device on a platform here on earth and person B enters his spacecraft. Each person then starts their device at the exact same moment in time. 4) Person B flies off at the speed of light, person A sees B's water dropping at a slower rate, and person B sees person A's water dropping at a slower rate. 5) Person B lands and person A says "B your water is dropping slower than mine and making it difficult to stay in sync with you, so before you take off again I am going to speed up your water drops so we can stay in sync." B says "you're the boss, adjust my device to match yours since your water drop rate is what matters" 6) Person B takes off again with his sped up device, now person A sees that both devices are dropping water at the same rate. That is my basic thought which is my understanding of special relativity as the GPS is concerned. I understand this in theory and this basically for me explains how satellites communicate with precision to earth. What I don't understand is if no adjustments were made would person A run out of water first? Since B is dripping at a slower rate as observed by A than this would seem logical. If no adjustments were made what would happen if B were to land and water bottles were compared? OR if each device had an alarm with a flashing light that triggered when the other persons water bottle ran out which persons alarm would trigger first? If person A ran out of water would he see his alarm going off on person B's device? Would the opposite be true if person B was looking at person A's device? It seems to me that if this example were real and I was person A I could only come to one conclusion. I would state "While person B's water seems to be dripping more slowly than mine I understand that our devices are in sync, therefore I can only conclude that person B is in motion relative to me and that light is playing a trick on me. I know this was very long but I would truly appreciate any insight on this personal struggle of mine. Know that any information or insight given will not be wasted. Thanks!