Netta Engelhardt: Puzzles in the Black Hole Interior: Past, Present and Future (April 22, 2026)

In this Presidential Lecture, Netta Engelhardt explores the black hole information paradox, a central puzzle in theoretical physics. She begins by defining black holes as regions from which nothing, not even light, can escape, and explains how this leads to a conflict with quantum mechanics, which forbids information destruction. The lecture provides accessible introductions to general relativity and quantum mechanics, using light cones and quantum coins to illustrate key concepts. Engelhardt then traces the history of the paradox, from Hawking’s discovery in the 1970s to the recent revolution in 2019, which involved new calculations using the holographic principle and quantum extremal surfaces. She explains how these developments have led to a better understanding of how information can be encoded in Hawking radiation, potentially resolving the paradox. Finally, she discusses the implications for quantum gravity and cosmology, including questions about the Big Bang and the nature of spacetime. The talk is aimed at a general audience but includes technical depth, and it highlights the ongoing excitement and open questions in the field.