Hyperspace is bending the universe for a extremely short amount of time so that two points are closer to each other. You are moving faster than the speed of light without moving much at all. For long trips however, some weaker species and elderly humans must go into a hibernation-like state. For the watching theship, it might is nearly instant unless traveling outside of Skyriver (the galaxy) but for people in the ship, it might take a while. That Is because when in Hyperspace you are technically outside of space-time.