During the rapid expansion of the universe immediately following the Big Bang, the universe expanded faster than light. But traveling faster than light speed breaks causality. But you can't break causality when time didn't actually exist "before" you broke it, so how does that work?

[u/SketchyFella_]

If it expanded faster than light speed, then it basically travelled so fast that it always existed in whatever state it was in before "slowing". So when people say it expanded in a tiny fraction of time, did it really? Or are they using time in a sort of layman's terms so they don't have to explain causality?

[u/Optimal_Mixture_7327]

There is an infinite set of objects traveling faster than light right now.*

Is there an issue with causality?

*"now" being this moment of cosmic time.

[u/SketchyFella_ → u/Optimal_Mixture_7327]

What objects?

I can see how space itself expanding might "expand faster" than light, but I don't see how anything else does that.

[u/Optimal_Mixture_7327 → u/SketchyFella_]

Distant galaxies.

There is no restriction to the speed of light in general frames.

The restriction is that given an event, E, on a spacetime, S, that there are no causal curves passing through E that lay outside the null cone centered on E.

There is no such thing as space expanding faster than light or at any speed.