 So black holes, what is a black hole? A black hole is just a region of space where gravity is so strong that nothing can come out of there, right? Not even light. The boundary of the black hole is called the event horizon. And the history of black holes is a great study in humility because we've kept discovering over and over again that we were all wrong about them. First, when Einstein wrote down his equations of gravity, this guy called Schwarzschild discovered the black hole solution. And then for decades and decades people thought that actually the event horizon itself was some kind of singularity, was something that was really weird with space. Then it turned out that was just a math error people had made. There's nothing special that happens if you fall through the event horizon, except that if you're keeping track, you have a sinking feeling that you're never coming back. It's like the event horizon of a black hole is like if you're swimming in the Niagara River upstream from the waterfall, there's one particular line through the river where the water accelerates to go faster than you can swim. You're not going to die there. You're just going to have that oh shit moment experience. And then people thought well you're going to only die when you come into the middle of a black hole where there is this thing called the singularity, either a point or a ring, depending on whether it's spinning. Then it turned out actually there is another thing called the inner horizon where you might actually die earlier by hitting things that come at you at the speed of light. And then very recently there's a firewall hypothesis saying actually maybe you do die after all at event horizon. And the short answer as to what the truth is is we really don't know. We're studying and it's a key in understanding the theory of everything. Yeah because it turns out that they're really rigorously answering these questions. It's not enough to just work with Einstein's theory of gravity. You also throwing quantum mechanics into that. And those are the two theories we mentioned earlier don't get along so you don't ultimately know. So the way I see it is actually as an opportunity. If we can figure out what's going on with black holes and maybe even get some clues by looking at them, then that can actually maybe be the master key that can help us unlock some of the deepest mysteries of quantum gravity and get a unified theory of physics.