Yeah, I'm not a physicist but hearing a good explanation of the time-space four-vector being constant as an explanation for time dilation (among other things) w

Yeah, I'm not a physicist but hearing a good explanation of the time-space four-vector being constant as an explanation for time dilation (among other things) was a real light bulb moment for me. It's also why I'm basically convinced that any sort of FTL (including wormholes and compressing space), time travel or cheating causality is essentially impossible, no matter what results you contrive by putting things like negative mass and/or energy into various equations. How this all gets reconciled with quantum mechanics is another matter. Part of me wonders if the problem isn't just that space and time are ultimately discrete (at the Planck unit level) and our equations describing it are continuous. But again, I'm no physicist.