eli5 how do we know nothing is faster than light?

Question

eli5 how do we know nothing is faster than light?

In: 452

Answer 1

We don’t know, at least not for sure.

All the theoretical and practical knowledge we have about the universe says it *should* be impossible, and everything we know about spacetime, mass, energy, etc breaks down as you approach the speed of light.

But there’s at least one theoretical particle (tachyons) that would *always* be faster than light.
https://en.wikipedia.org/wiki/Tachyon