Black holes are funky things. They have a lot of science to them and it seems like something you’d find in a science-fiction book to fix a plot-hole but they do exist and get even weirder the more you learn about them.
I’ve already explained how to time travel with black holes, the huge amount of mass the black hole has warps space and time around it causing time to go slower closer to it compared to something farther away. Orbiting the black hole would more or less fast forward you in time, pushing you into the future faster than something not being affected by this black hole. This is just one of the weird things about black holes, it gets worse.
I’ve also explained how black holes are formed and how they need to be spinning to allow the point in the center, the singularity, to be a ring instead of point. This allows the possibility of moving through the ring and potentially moving through time and space but at that point it’s complete speculation.
The outside of the black hole is the weirdest part of it that can be observed without actually being inside the black hole. If you cross the event horizon, the point where you cannot escape being pulled towards the black hole, then you would not see that thing enter it. You would see them stop where they crossed it and that’s it. At that point the indestructible person, that can somehow not die from all the forces and radiation of the black hole, wouldn’t even notice that they passed through the event horizon. they would continue towards the singularity while the person on the outside watching would just see the person frozen there in time. Eventually the image of the person would just fade away.
Now begins the fun part. The reason you cannot escape the inside of a black hole is not because it’s gravity is too strong. This is what is always assumed because of the way gravity is taught as two objects being attracted to each other, but this is also wrong according to Einstein’s theory of relativity. His theory says that what we see as gravity is really an object distorting space and time around itself proportional to its mass. If you pretended all of space was a grid you could imagine a bowling ball on a mattress, it sinks a lot doesn’t it? Now imagine a baseball on a mattress, it doesn’t sink as much. This is what a black hole, and anything else with mass like Earth, does to space around it, it warps it. The picture to the right illustrates this example.
The real reason you cannot escape a black hole is because, if time was the y-axis and space was the x-axis on a graph, once you cross the event horizon time and space switch. Yes you read that correctly, THEY SWITCH. This is practically impossible to actually comprehend but the easiest way to think about it is this, once you you cross the event horizon you cannot move out of the black hole because you would have to move backwards in time to move away from the black hole’s center since space and time switched. Time naturally moves forward so since time and space switched, time is bringing you towards the center. To physically move away from the center you would have to essentially travel backwards in time which, for intents and purposes, is impossible in those circumstances. A funny byproduct of this situation is that you wouldn’t be able to see anything in front of you since, with time and space switched, it literally hasn’t happened yet for you to see.
An interesting thing about a Kerr black hole, or a black hole that is spinning, is that it has TWO event horizons. One is the normal outside one but then there is a second one closer inside, a drawing below shows this. The best part about this is that the second event horizon switches time and space back to normal so you could actually move around in the inner section of the black hole, you still can’t get out since you’d have to travel through the first section of the black hole, but then again this whole scenario is ignoring a lot of other things that would have killed a person by now.
In this section of the black hole you would, theoretically, be able to see the ring singularity in the center. At this point we don’t know what could happen. Maybe you can travel through the ring over and over and go backwards in time and meet yourself, maybe the ring is a gateway to a different universe, no one knows. The sad part is that no one will probably ever know unless they are the one who go into the black hole since once you go in you can never escape. Would your curiosity be strong enough to get you to enter a black hole given the chance?