Starts With A Bang

Nobody Knows Where A Black Hole’s Information Goes (Synopsis)

Black holes can devour anything in the Universe, but getting the information out again still proves elusive. Image credit: ESO, ESA/Hubble, M. Kornmesser.

“Work gives you meaning and purpose and life is empty without it.” -Stephen Hawking

Throw a book into a black hole, and the information must somehow wind up inside. Same goes for a star, a planet, or even a single proton: that information must be maintained. But allow enough time to pass, and quantum theory and general relativity, combined, predict something troubling: that black hole will decay, and none of the information will come out in the decay products.

While Einstein’s theory makes explicit predictions for a black hole’s event horizon and the spacetime just outside, quantum corrections could alter that significantly. Image credit: NASA.

In physics, that’s what we call a paradox. Every individual quantum process affecting a particle and its interactions should be time-reversible, but if we run the clock backwards on black hole evaporation, that’s an impossibility. The worst part of the information paradox is that every proposed solution has problems that may be even greater than the paradox itself.

Information may come out of the black hole at early times, but the mechanism has not been uncovered. Image credit: Petr Kratochvil.

Join Sabine Hossenfelder on a wonderful exploration of the problem, the possibilities, and why it’s continued to stump so many for so long!