“Maybe that is our mistake: maybe there are no particle positions and velocities, but only waves. It is just that we try to fit the waves to our preconceived ideas of positions and velocities. The resulting mismatch is the cause of the apparent unpredictability.” -Stephen Hawking
Black holes are the densest, most compact objects in the Universe, with anywhere from a few to many billions of solar masses of material concentrated into a singularity. At a certain distance away from that singularity, every black hole has an event horizon: a region of space from within which nothing can escape, not even massless particles like light. That distance, and the size of the event horizon, is prescribed solely by the black hole’s mass.
Outside of the event horizon, however, black holes emit Hawking radiation, a blackbody spectrum of low-energy photons that will result in the eventual evaporation of the black hole entirely. But Hawking’s own picture of how this happens, of virtual particle/antiparticle pairs where one falls into the black hole with negative energy and the other escapes with positive energy, is woefully incorrect, and perhaps the greatest source of misunderstandings concerning black holes.