Stephen Hawking cancels appearances because of "ill health"

Cambridge University today said that Stephen Hawking is cancelling several public appearances because of ill health.

The celebrated physicist had been scheduled to record BBC's annual Reith Lecture Thursday at the Royal Institution in London.

From the Associated Press:

The university did not provide any details about the condition of the 73-year-old professor, who is thought to be one of the longest-living survivors of motor neurone disease.

Hawking was expected to discuss black holes and answer questions from BBC radio listeners for his lecture. The BBC said his lecture is postponed until the new year and once he is better.