In another comment on this thread they explained that space and time are parts of the same vector, <x, y, z, t>, with velocity being the speed of light. Here you mentioned time is frozen at the black hole event horizon - does this have to do with the theory that we can use black holes as "portals" to distant parts of the galaxy? So if time is 0 and we have <x, y, z, 0>, does this mean we travel at the speed of light?