A proof of the strong cosmic censorship conjecture

The Penrose strong cosmic censorship conjecture asserts that Cauchy horizons inside dynamically formed black holes are unstable to remnant matter fields that fall into the black holes. The physical importance of this conjecture stems from the fact that it provides a necessary condition for general relativity to be a truly deterministic theory of gravity. Determining the fate of the Penrose conjecture in non-asymptotically flat black-hole spacetimes has been the focus of intense research efforts in recent years. In the present essay we provide a remarkably compact proof, which is based on Bekenstein's generalized second law of thermodynamics, for the validity of the intriguing Penrose conjecture in physically realistic (dynamically formed) curved black-hole spacetimes.