Black holes are some of the most puzzling objects that can be found anywhere in the universe. The gravitational pull of an object is so strong that nothing, even not light, can escape from it if the object is dense and massive enough. Several different types of physical black holes have been discovered, ranging from stellar-mass scale ones in our own galaxy to supermassive ones at the centers of the vast majority of galaxies, with masses many millions or even billions of times greater than the mass of our own Sun. The fact that light can never escape from within the event horizon establishes a boundary in space: once you cross it, you’re doomed to collide with the central singularity, which is the most important property surrounding the event horizon. But what would you see if you were to fall into the water? Would the lights remain on, or would the entire universe go dark? – At long last, physics has figured out the solution, and it’s absolutely stunning.
We’ve been able to observe the motions of stars around a central point mass with a mass of approximately 4 million solar masses that emits no light at all, which is located at the center of our own galaxy. It is certain that this object in particular — Sagittarius A* — is a black hole, as evidenced by the fact that the stars which have been orbiting it for more than two decades have shown us. Even if the black hole eventually died, emitting all of the particles it had absorbed (including your body), it would be impossible to determine whether or not those particles were in fact your body. Fortunately, Stephen Hawking discovered a way to ensure that the information about your body was not lost.
Before entering a black hole, it’s impossible to tell whether or not there is one from the outside. Only when you’re inside can you tell for sure. Suppose you were to cross the event horizon and found a black hole… Sayonara… In contrast, if you were to happen to be in a reality in which the black hole did not exist, you would still be alive. Everything is the same, just in a different reality. If you tried to return to our place, there would be no way. Would you be willing to take a chance on it?