I have read several books on relativity and find the subject fascinating. But there are a couple of things that I hope someone can help me understand. The big question on my mind is "why is light always associated with time"? It seems to my simple mind that light just portrays a visual representation of events and that the peculiarities of light just alter our perception of the timing of events but not of the actual time that the event occurred at d=0 Why pick light over sound for instance? I know that we can view a cosmic event and say that it occurred 93 million years ago and we acknowledge that the event didn't just occur now but much earlier in time. So why do we treat things differently when talking about events happening on a train for instance? I am not disputing the theories and experimental results discovered about light to date although I sometimes wonder if using an atomic clock, which works on electromechanical principles, can be misleading us.