Friends, In a recent post I said "The speed of light is the same for all observers". I meant unequivocally. With no exceptions. Always the same. No tricks or gimmicks. But I was quickly corrected in triplicate! 'To be exact: The speed of light is the same for all inertial observers. There is a significant difference.' If the difference is significant, then I need to understand it. Does this mean the speed of light can change for an observer?