Quick lesson on time dialation, the closer you are to a heavy object, the slower time goes for you, if the mass is large enough, one could freeze in time. Now, send a few person you trust to a remote planet where life is just starting to take off, you yourself staying besides say, a supermassive black hole, aka Joe, wait for a few hours, what do you get? Simple, a bunch of very advanced civilisations, probably a few with mal intent, which is way ahead of you in terms of technology. What do you do now?