London:
Defying the odds of medicine, Stephen Hawking, widely regarded as one of the most brilliant theoretical physicists, celebrated his 70th birthday on Sunday.
The Lucasian professor of mathematics and theoretical physics at the University of Cambridge has 12 honorary degrees. But besides his academic achievements, the professor is also something of a medical marvel.
He has long defied and baffled medical experts who predicted he had just months to live in 1963 when he was diagnosed with Motor Neuron Disease (MND), a deadly disease.
Only five per cent of people with the form of MND that he has - a condition called amyotrophic lateral sclerosis (ALS) or Lou Gehrig's disease - survive for more than a decade after diagnosis.
The fact that Hawking, Britain's most celebrated physicist, has lived for nearly half a century with a condition that progressively attacks the nerves serving the muscles of the body has been described as remarkable.
"I have been lucky, that my condition has progressed more slowly than is often the case. But it shows that one need not lose hope," Hawking says.
"I am quite often asked: 'How do you feel about having ALS?'
"The answer is, not a lot. I try to lead as normal a life as possible, and not think about my condition, or regret the things it prevents me from doing, which are not that many," the BBC quoted him as saying.
Currently Director of Research at the Department of Applied Mathematics and Theoretical Physics at the University of Cambridge, where he also founded the Centre for Theoretical Cosmology, Hawking previously (1979-2009) held the Lucasian Professorship of Mathematics at Cambridge, a post once held by Isaac Newton.
Although he has now stepped down from the Lucasian chair after a historic 30 years, he continues working at the University of Cambridge and recently published a new book - The Grand Design.
The grandfather-of-three continues to seek out new challenges.
Hawking recently experienced first-hand what space travel feels like by taking a zero-gravity flight in a specially modified plane.