[ben_w]

Thanks. Velocity is the derivative of position with regard to time. Does it exist if there is no time? It might be that momentum is the fundamental thing and velocity is just a consequence of it. Or not, I don’t know.

Momentum has a direct influence on Einstein field equations, and I don’t know enough maths to follow GR (just two A-levels) so I have no idea if that “direct” influence is still present at a no-more-future boundary condition.

My insufficient maths skills are, amongst other things, why I don’t trust my understanding that a black hole singularity really is a no-more-future boundary condition.