^I do like Roddenberry's explanation of it though. I know he was just stringing a bunch of BS together (and he even admitted as such) but it sounded good.
Well, not really. He was basically attempting to describe one of the core ideas of relativity, that the measurement of time is relative to the frame of reference in which it's measured rather than being a universal absolute, so that observers moving in different speeds and directions will perceive time differently. Although that wouldn't really work for warp-driven ships, since they don't undergo time dilation.