Renowned physicist Stephen Hawking was too ill to attend a symposium held in honor of his 70th birthday at the University of Cambridge in England Sunday.
But, in a recorded message, he repeated his call for humans to explore the universe for future homes. Hawking argued for continued space exploration, saying he didn't “think we will survive another thousand years without escaping beyond our fragile planet.”
A University of Cambridge vice chancellor told the conference that Hawking, who is almost completely paralyzed because of Lou Gehrig's disease, had only recently been discharged from the hospital for an unspecified ailment.
Hawking, the author of A Brief History of Time, was diagnosed with the incurable, degenerative disease at age 21 and told he only had two years to live. He has since been hailed as one of the most brilliant theoretical physicists since Albert Einstein.
Hawking relies on a computerized wheelchair to move around and a voice synthesizer to speak. His fragile health has forced him to cancel appearances in the past.
He concluded Sunday's message by imploring those present to “remember to look up at the stars and not down at your feet.”