Simultaneity Let's imagine there is a train moving at the speed of light. When in the middle, two lightning flashes appear on it's left and right. Why is it that it sees the right flash before the left? And if it is moving left to right, why does it see the left before the right? It is to do with the train's motion? It's position relative to the flash? If so, how? P.S: This is not a homework question, just a general question.