Hawking marks 75th birthday

Professor Stephen Hawking has celebrated his 75th birthday at a special series of public lectures about gravity and black holes.

The physicist and cosmologistgaveatalkreflecting on his life and scientific work at yesterday’s symposium at Cambridge University. It followed an afternoon of lectures from other distinguished scientists, including Professor Brian Cox.

Prof Hawking, who turned 75 in January, joked: “Actually, for those keeping count, I’m closer to 75-and-a-half. But that shouldn’t get in the way of a good celebration.”

In his talk, titled My Life In Physics, he recalled his diagnosis of amyotrophic lateral sclerosis, a form of motor neurone disease, at the age of 21.

“At first I became depressed,” he said. “After my expectations had been reduced to zero, every new day became a bonus and I began to appreciate everything I did have. While there’s life there’s hope.”