Event Horizon- The point of no return at the edge of a black hole. Because black holes are so massive, and so dense, there exists a point where space time is so warped, that even light cannot escape, but rather gets bent back into the black hole. The escape velocity is greater than the speed of light. This means that nothing can escape from inside the event horizon, not even light. This is why black holes are black. Because of this, it means that to an outside observer, there is no way to retrieve information from beyond the event horizon. We cannot know what is actually happening inside a black hole.
