The physicist and cosmologist was diagnosed with Lou Gehrig's disease when he was a 21-year-old student at Cambridge University. Most people die within a few years of the diagnosis, called motor neurone disease in the U.K. On Sunday, Hawking will turn 70.
``I don't know of anyone who's survived this long,'' said Ammar Al-Chalabi, director of the Motor Neurone Disease Care and Research Centre at King's College London. He does not treat Hawking and described his longevity as ``extraordinary.''
``It is unusual for (motor neurone disease) patients to survive for decades, but not unheard of,'' said Dr. Rup Tandan, a neurology professor at the University of Vermont College of Medicine. Still, Tandan said many longtime survivors had ventilators to breathe for them _ which Hawking does not.
Hawking first gained attention with his 1988 book ``A Brief History of Time,'' a simplified overview of the universe. It sold more than 10 million copies worldwide. His subsequent theories have revolutionized modern understanding of concepts like black holes and the Big Bang theory of how the universe began.
To mark his birthday Sunday, Cambridge University is holding a public symposium on ``The State of the Universe,'' featuring talks from 27 leading scientists, including Hawking himself. For 30 years, he held a mathematics post at the university previously held by Sir Isaac Newton. Hawking retired from that position in 2009 and is now director of research at the university's Centre for Theoretical Cosmology.
Hawking achieved all that despite being nearly entirely paralyzed and in a wheelchair since 1970. He now communicates only by twitching his right cheek. Since catching pneumonia in 1985, Hawking has needed around-the-clock care and relies on a computer and voice synthesizer to speak.
A tiny infrared sensor sits on his glasses, hooked up to a computer. The sensor detects Hawking's cheek pulses, which select words displayed on a computer screen. The chosen words are then spoken by the voice synthesizer. It can take up to 10 minutes for Hawking to formulate a single sentence.
``The only trouble is (the voice synthesizer) gives me an American accent,'' the Briton wrote on his website.
It took Hawking four years to write his last book, ``The Grand Design,'' missing his publisher's original deadline.
Hawking declined requests from The Associated Press for an interview, but his personal assistant, Judith Croasdell, spoke to the AP. She described her boss as remarkably patient.
``The way he communicates can seem frustratingly slow to most people but he doesn't let that impede his thinking,'' she said.
After a brief hospital stay, Hawking told her that he spent the time thinking about black holes.
Hawking typically comes into the office after a big breakfast and reading the news, Croasdell said. ``He's not an early morning person, but he does stay quite late,'' until about 7 or 8 in the evening, she said.
Hawking's rooftop university office is crammed full of memorabilia: family photos, a miniature NASA shuttle, and a signed picture of himself with President Barack Obama and his wife, Michelle. On top of physics books sits a disability access guide for the university.
Hawking's fame has led to guest appearances on some of his favorite television shows including ``The Simpsons'' and ``Star Trek.'' His animated likeness from ``The Simpsons'' has even been turned into an action figure _ one of which sits proudly on his office desk. There's also a Homer Simpson clock that Hawking is known to glare at when visitors are late for an appointment.
``He's a big ham, he loves the spotlight,'' said Kitty Ferguson, who's written two biographies of the physicist.
She said he has a wry sense of humor and has programmed his computer to respond to random encounters with people who ask if he's Stephen Hawking. ``No, but I'm often mistaken for that man,'' his voice synthesizer deadpans.
Lou Gehrig's disease, also called amyotrophic lateral sclerosis, or ALS, attacks motor neurons, cells that control the muscles. Patients typically suffer muscle weakness and wasting, become paralyzed and have problems talking, swallowing and breathing. Only about 10 percent of patients live longer than a decade.
People who are stricken at a young age, as Hawking was, generally have a better chance of surviving longer. Most people are diagnosed between 50 and 70. Life expectancy generally ranges from two to five years after symptoms like slurred speech, difficulty swallowing and muscle weakness set in. Hawking's personal physicians don't discuss his condition with the press, Croasdell said.
For some reason, the disease has progressed more slowly in Hawking than in most. Al-Chalabi and colleagues are analyzing a DNA sample from Hawking, along with those of other patients, to see if there is something rare about his disease or any genetic mutations that could explain his long survival and if that information could be used to help others.
Some experts said the type of care Hawking has, including about a dozen health workers 24 hours a day, may have extended his life expectancy.
``The disease can sometimes stabilize and then the kind of care delivered may be a factor in survival,'' said Virginia Lee, a brain disease expert at the University of Pennsylvania School of Medicine. ``Remaining mentally alert is also extremely important and he has clearly done that.''
Hawking says he tries not to think about his limitations.
``I have had (Lou Gehrig's disease) for practically all my adult life,'' he says on his website. ``Yet it has not prevented me from having a very attractive family and being successful in my work,'' he writes. ``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.''
From the office pictures documenting his achievements, that certainly seems to be the case. Framed photos show the physicist with several popes and on memorable trips to China and Easter Island.
He has even flown in a space simulator. In 2007, Hawking took a zero-gravity flight in Florida, the first time in 40 years he abandoned his wheelchair.
``That was the happiest I've ever seen Stephen,'' said Sam Blackburn, Hawking's graduate assistant, who accompanied him on the ride along with about a half-dozen others, including two doctors. ``He just had the biggest grin on his face.''
Hawking has also been married twice and has three children and three grandchildren. With his daughter Lucy, he has written several children's books on physics.
Al-Chalabi said most patients with Lou Gehrig's disease succumb after their breathing muscles stop working. He had no predictions for what the biggest health risks to Hawking's future might be.
``He is truly remarkable,'' Al-Chalabi said. ``This is someone who's managed to find ways around every single problem the disease has thrown at him.''
<관련 한글 기사>
호킹 박사 "여자는 완벽한 미스터리"
세계적인 물리학자인 스티븐 호킹(69)이지만 여자 문제 만큼은 풀지 못해 지금도 끙끙댄다는 재미있는 인터뷰 내용이 과학 잡지 뉴사이언티스트에 실렸다.
호킹은 8일 70세 생일을 기념해 이 잡지와 가진 인터뷰에서 "요즘 무엇을 생각하면서 지내느냐"는 질문에 "여자. 그들은 완벽한 미스터리(Women. They are a comp lete mystery)"라고 답했다.
우주의 신비를 풀어내는데 큰 업적을 세운, 세계에서 가장 유명한 과학자지만 평범한 남성들 못지 않게 많은 시간을 평생 수수께끼였던 여성 문제를 생각하면서 지낸다는 것이다.
이 잡지는 그의 70세 생일을 기념해 케임브리지대학에서 열리는 심포지엄에 앞서 발간됐다.
우주를 이해하는데 혁명적인 역할을 한 것은 무엇이냐는 질문에 호킹 박사는 "강입자 충돌기의 발견"이라고 말했다.
자신이 저지른 가장 큰 학문적 실수에 대해서는 "정보가 블랙홀에서 파괴된다고 생각했었다"면서 "대응이론이 1997년 발전하면서 생각을 바꾸게 만들었다"고 고백했다.
지난해초 호킹 박사는 일간 가디언과의 인터뷰에서 "죽음을 두려워하지 않는다"
면서 "천국은 어둠을 두려워하는 사람들이 만들어낸 동화일 뿐"이라고 말해 논란을 불러일으켰다.
호킹 박사는 21세 때 전신이 마비되는 근위축성 측색경화증을 진단받아 30대까지 살지 못할 것이라는 예상이 많았지만 질병을 이겨내며 학문적 업적을 쌓아왔다.
그는 자신의 목표가 "우주의 완전한 이해"라고 말했으며 그의 연구는 대우주에 관한 상대성 이론과 소우주에 관한 양자이론을 통합하는 데 집중됐다.
호킹 박사는 과거 아이작 뉴턴이 맡았던 케임브리지대 루카시언 석좌교수직을 1 979년부터 30년간 맡아오다가 2009년 10월 건강이 악화된뒤 끈이론의 개척자인 마이 클 그린 교수에서 넘겨줬다.
