The Page Curve

In 1993, physicist Don Page argued that if information survives black hole evaporation, the entanglement entropy of the Hawking radiation must follow a specific curve: rising as the black hole emits radiation, peaking at the halfway point, then falling as the remaining radiation becomes increasingly correlated.

For decades, no one could derive this Page curve from first principles. Then in 2019, calculations using the island formula reproduced it exactly — hailed as the biggest progress on the paradox in decades, and strong evidence that information does escape.