In the 70s, I remember reading "The Quincunx of Time", which made great use of a key distinction (for the purposes of some classic 70s scifi):
It's not that nothing can move faster than the speed of light, it's that nothing can accelerate to a speed faster than the speed of light.
If you could bring particles into being that already moved faster than light, they would not violate our understanding of relativity or the rest of physics. Hence ... the tachyon.
https://en.wikipedia.org/wiki/Tachyon
It's not that nothing can move faster than the speed of light, it's that nothing can accelerate to a speed faster than the speed of light.
If you could bring particles into being that already moved faster than light, they would not violate our understanding of relativity or the rest of physics. Hence ... the tachyon. https://en.wikipedia.org/wiki/Tachyon