I don't remember reading this before (in the Penrose obituary), that is that he discovered Hawking radiation when trying to prove that it didn't exist: > Beken

I don't remember reading this before (in the Penrose obituary), that is that he discovered Hawking radiation when trying to prove that it didn't exist: > Bekenstein realised this was key to the entropy problem. Every time a black hole swallows matter, its entropy appears to be lost, and at the same time, its event horizon grows. So, Bekenstein suggested, what if – to preserve the second law – the area of the horizon is itself a measure of entropy? > Hawking immediately disliked the idea and was angry that his own work had been used in support of a concept so flawed. With entropy comes heat, but the black hole couldn’t be radiating heat – nothing can escape its pull of gravity. During a break from the lectures, Hawking got together with colleagues Brandon Carter, who also studied under Sciama, and James Bardeen, of the University of Washington, and confronted Bekenstein. > The disagreement bothered Bekenstein. “These three were senior people. I was just out of my PhD. You worry whether you are just stupid and these guys know the truth,” he recalls. > Back in Cambridge, Hawking set out to prove Bekenstein wrong. Instead, he discovered the precise form of the mathematical relationship between entropy and the black hole’s horizon. Rather than destroying the idea, he had confirmed it. It was Hawking’s greatest breakthrough.