Like Einstein, he is as famous for his story as for his science.
At the age of 21, the British physicist Stephen Hawking was found to have 2)amyotrophic lateral sclerosis, Lou Gehrig's disease. While A.L.S. is usually fatal within five years, Dr. Hawking lived on and flourished, producing some of the most important cosmological research of his time.
In the 1960s, with Sir Roger Penrose, he used mathematics to 3)explicate the properties of black holes. In 1973, he applied Einstein's general theory of relativity to the principles of 4)quantum mechanics. And he showed that black holes were not completely black but could leak radiation and eventually explode and disappear, a finding that is still 5)reverberating through physics and cosmology.
Dr. Hawking, in 1988, tried to explain what he knew about the boundaries of the universe to the 6)lay public in A Brief History of Time: From Big Bang to Black Holes. The book sold more than 10 million copies and was on best-seller lists for more than two years.
Today, at 69, Dr. Hawking is one of the longest-living survivors of A.L.S., and perhaps the most inspirational. Mostly paralyzed, he can speak only through a computerized voice simulator.
On a screen attached to his wheelchair, commonly used words flash past him. With a cheek muscle, he signals an electronic sensor in his eyeglasses to transmit instructions to the computer. In this way he slowly builds sentences; the computer transforms them into the metallic, 7)otherworldly voice familiar to Dr. Hawking's 8)legion of fans.
It's an exhausting and time-consuming process. Yet this is how he stays connected to the world, directing research at the Center for Theoretical Cosmology at the University of Cambridge, writing 9)prolifically for specialists and 10)generalists alike and lecturing to 11)rapt audiences from France to Fiji.
Dr. Hawking came here in April at the invitation of a friend, the cosmologist Lawrence Krauss, for a science festival sponsored by the Origins Project of Arizona State University. His lecture, “My Brief History,” was not all 12)quarks and black holes. At one point, he spoke of the special joys of scientific discovery.
The next afternoon, Dr. Hawking sat with me for a 13)rare interview. Well, a kind of interview, actually.
Ten questions were sent to his daughter, Lucy Hawking, 40, a week before the meeting. So as not to exhaust her father, who has grown weaker since a near-fatal illness two years ago, Ms. Hawking read them to him over a period of days.
During our meeting, the physicist played back his answers. Only one exchange, the last, was spontaneous. Yet despite the limitations, it was Dr. Hawking who wanted to do the interview in person rather than by e-mail.
Some background on the second query, the one about 14)extraterrestrials. For the past year, Lucy Hawking was writer 15)in residence at the Origins Project at Arizona State University. As part of her work, she and Paul Davies, a physicist at Arizona State, started a contest, “Dear Aliens,” inviting Phoenix schoolchildren to write essays about what they might say to space beings trying to contact Planet Earth.
Now let's look at some of those questions.
Q. At the beginning of May, your daughter, Lucy, and Paul Davies, the Arizona State University physicist, sent a message into space from an Arizona schoolchild to potential extraterrestrials out there in the universe. Now, you've said elsewhere that you think it's a bad idea for humans to make contact with other forms of life. Given this, did you suggest to Lucy that she not do it? Hypothetically, let's say as a fantasy, if you were to send such a message into space, how would it read?
A. Previously I have said it would be a bad idea to contact aliens because they might be so greatly advanced compared to us, that our civilization might not survive the experience. The “Dear Aliens” competition is based on a different premise.
It assumes that an intelligent extraterrestrial life form has already made contact with us and we need to formulate a reply. The competition asks school-age students to think creatively and scientifically in order to find a way to explain human life on this planet to some 16)inquisitive aliens. I have no doubt that if we are ever contacted by such beings, we would want to respond.
I also think it is an interesting question to 17)pose to young people as it requires them to think about the human race and our planet as a whole. It asks students to define who we are and what we have done.
Q. Given all you've experienced, what words would you offer someone who has been diagnosed with a serious illness, perhaps A.L.S.?
A. My advice to other disabled people would be, concentrate on things your disability doesn't prevent you doing well, and don't regret the things it interferes with. Don't be disabled in spirit, as well as physically.
Q. I'm wondering about your book A Brief History of Time. Were you surprised by the enormous success of it? Do you believe that most of your readers understood it? Or is it enough that they were interested and wanted to? Or, in another way: what are the implications of your popular books for science education?
A. I had not expected A Brief History of Time to be a best seller. It was my first popular book and aroused a great deal of interest.
Initially, many people found it difficult to understand. I therefore decided to try to write a new version that would be easier to follow. I took the opportunity to add material on new developments since the first book, and I left out some things of a more technical nature. This resulted in a follow-up entitled A Briefer History of Time, which is slightly briefer, but its main claim would be to make it more accessible.
Q. Here on Earth, the last few months have just been devastating. What were your feelings as you read of earthquakes, revolutions, counter-revolutions and nuclear meltdowns in Japan? Have you been as personally shaken up as the rest of us?
A. I have visited Japan several times and have always been shown wonderful hospitality. I am deeply saddened for my Japanese colleagues and friends, who have suffered such a 18)catastrophic event. I hope there will be a global effort to help Japan recover. We, as a species, have survived many natural disasters and difficult situations, and I know that the human spirit is capable of enduring terrible hardships.