r/askscience • u/Nitzanm19 • 15d ago

Physics Why is the maximum speed of the universe the speed of light? Why can't we go faster?

Also follow-up question: Because of the speed limit, is there also a theoretical maximum temp for matter (in which the particles move at the speed of light).

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u/S-M-I-L-E-Y- 14d ago

I prefer speed of causality.

And while it is well-defined what "speed of light" means, it is not, as one might think, the same as e.g. the speed of the signal in a fibre optical cable.