Why can't we go faster than light?

We cannot go faster than light, they say. Well, there is a different angle to look at this: you are, right now, travelling at the speed of light. Every person, every object is travelling exactly at the speed of light in the “bloc Universe”. If you are immobile, you are travelling at the speed of light along the “time” axis of the bloc Universe. It’s as if every object had a speed vector in the block Universe that had constant length. If you don’t move, your speed vector if aligned with the time axis: time is passing at normal speed for you. But if you start moving, this speed vector will start to tilt, having a non-null projection on the space axis, and a smaller projection on the time axis: time is passing slower when you travel. If you travel at the speed of light, your vector would be fully aligned with the space axis: time does not pass anymore for you. Indeed, for photons time is not passing.

This is also a good visualization to understand the twins paradox: the twin travelling has a tilted vector, and thus for him time is passing slower. When he returns on earth, his twin has aged more. When our travelling twin thought he left only one year, his brother on earth waited for him 50 years.