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Hawking worked at the institute three mornings a week. It was too far from Little St. Mary's Lane to get to by wheelchair. Instead, he had managed to acquire a three-wheeled invalid car, which he drove out into the suburbs on the main roads. Mitton would meet him at his car and help him out of the
little blue vehicle and into the main building. Hawking had his own office, and, as his prestige grew during the following years, a string of eminent astronomers and theoretical physicists was drawn to the institute to confer with him. Mitton describes him as a human magnet in the world of physics. Graduate students as well as professional scientists from all over the world were attracted to the institute mainly because of his presence there.

Hawking was never interested in observational astronomy. While an undergraduate at Oxford, he had attended a vacation course at the Royal Greenwich Observatory, helping Astronomer Royal Sir Richard Woolley to measure the components of double stars. However, so the story goes, upon looking through the telescope and seeing nothing more impressive than a couple of hazy dots in the star field, Hawking was convinced that theoretical physics would be more interesting. To this day, he has looked through a telescope no more than a handful of times. At the Institute of Astronomy, the work Hawking was interested in pursuing was conducted in his head or with pen, paper, and computer.

Mitton recalls that Hawking was not the easiest person to work with. He found him irritable and impatient, and he remembers very little of the famous Hawking wit and humor. Secretaries apparently also found him difficult, and there were many occasions when a newly employed assistant would come to see Mitton on the verge of tears, complaining of over-demanding workloads. Hawking always wanted things done yesterday. At such times, Mitton had to remind himself and the secretaries working for him that such moods were perhaps a symptom of the man's condition.

Others would disagree. Roger Penrose has pointed out that Hawking displays an unusual cheerfulness and sense of humor in the face of adversity. He has seen Hawking in a bad mood, irritable and impatient with those around him, but he believes that many people with ALS develop a compensation mechanism, a system which acts as an antidepressant. It would perhaps be nearer the mark to say that Hawking's behavior has more to do with his own character than any effect of his illness. Like the rest of us, he is sometimes short and impatient with those around him, and he does not suffer fools gladly. Because he works at such an intense pace, putting great demands on himself, he expects everyone else to have the same energy and drive. Perhaps he simply didn't get on with the secretaries at the Institute of Astronomy.

However, the institute seemed to be more aware of his worth than his own college was. The authorities made every effort to assist him in his work and to compensate for his disabilities. They had an automatic phone fitted in his office, preprogrammed to enable him to reach other numbers at the push of a single button. But this was long before digital technology, and the device was really little more than a box of tricks with a vast number of leads and connections sprouting from a junction box in the corner of the room. It took post office engineers over a week to install it.

There was a definite buzz in Cambridge about Hawking and his work, even before he joined the Institute of Theoretical Astronomy. He had a certain aura about him. Long before he had made his mark on cosmology, among graduate students there was an air of reverence accompanying the name Stephen Hawking. Such early discipleship illustrates the beginnings
of the cult status that has surrounded many of the things Hawking has said and done during his career. Even in the early 1970s, it was possible to see that the image of the crippled genius, so beloved of the media, was beginning to take root in the minds of those on the periphery of Hawking's life and work. Instead of this image diminishing or fading away as his career has blossomed, with each fresh achievement his status as the new Einstein—the purely cerebral creature trapped inside an inoperative body—has grown.

Mitton recalls that, by the time of their first meeting in 1972, Hawking's speech had deteriorated considerably. It was essential to concentrate hard on what he was saying in order to understand him. Mitton found that he always had to face Hawking and watch what he was saying as well as listen intently; even then, it was not easy. The best way to communicate, Mitton found, was to ask questions that required only negative or affirmative answers. So instead of asking, “When would you like to go to lunch, Stephen?,” it was far easier to say, “We are going to lunch at 12:30. Is that all right?” Fischer Dilke, who wrote and directed one of the first television documentaries about Hawking, disagrees. He says that Hawking hates nothing more than being asked such questions, because it is a sign to him that the person he is talking to is not treating him in a normal way. It obliges him to answer only “Yes” or “No,” and he would, quite naturally, like to be engaged in a standard conversation.

In retrospect, the seventies may be viewed as something of a gray decade. After the optimism and hope of the sixties,
the West, with the possible exception of West Germany, was thrown into recession; only in Japan did a combination of postwar determination, a flair for the commercial application of Western technology, and sheer hard work set the pattern for industrial growth. Britain's economy nearly foundered, hammered by a series of disastrous strikes and political turmoil. The decade began with a Labor government, which lasted until June of 1970 when Edward Heath narrowly beat Harold Wilson in a surprise victory, and ended with a new style of Tory government in the shape of the country's first female prime minister, Margaret Thatcher.

In April 1970, the world held its breath as the drama of Apollo 13 was enacted hundreds of thousands of miles out in space, and the crippled spaceship limped home to safety. In September, high drama of a different kind was played out in the Jordanian desert when Middle Eastern terrorists blew up three jet airliners. The world lost a charismatic and influential figure in the shape of Hawking's schoolboy hero, Bertrand Russell, who died at the age of ninety-seven. And it was in that year that Stephen Hawking began to turn his attention toward the exotic astronomical objects recently dubbed “black holes” and once again found himself in collaboration with the mathematician Roger Penrose.

It is often the case with scientific discovery that a crucial step forward comes through inspiration at an unexpected moment, and Hawking is fond of recalling the story of when his first black hole breakthrough came to him. Soon after the birth of his second child, Lucy, in November 1970, he was thinking about black holes as he got ready for bed one night. As he says:

My disability makes this rather a slow process, so I had plenty of time. Suddenly, I realized that many of the techniques that Penrose and I had developed to prove singularities could be applied to black holes.
2

At that time, notions of what a black hole was really like were pretty hazy, and both Penrose and Hawking had been trying to come up with some way of stating which points in spacetime were inside a black hole and which were outside. It was just as he was about to get into bed one night that an obvious solution struck him. The answer to the problem was actually one that he claims Penrose had originally suggested but had not applied to the situation they were studying. The science is described in the next chapter; suffice it to say that the resolution was so exciting that Hawking got very little sleep that night. Early the next morning, he was on the phone to Penrose.

For the next two years (as we describe more fully in
Chapter 9
), the pair of them developed their ideas about the physics of black holes. As they worked, they came to see that the way they had originally perceived black-hole physics was not as clear-cut as it ought to be. To properly get to grips with it required them to dust away the mental cobwebs of dimly remembered physical concepts they had not thought about since undergraduate days. In particular, Hawking was gaining a renewed interest in a field called thermodynamics, developed by Lord Kelvin and others in the nineteenth century.

No one would have imagined that thermodynamics had any relevance to black holes at all. As Dennis Overbye has put it, “It was as if he had popped the hood on a Ferrari and
found an antique steam engine chugging away inside.”
3
It was ridiculous—thermodynamics was used to study gases under pressure, heat transfer, and the efficiency of steam engines, not such exotic objects as black holes. Little did Hawking realize at the time that thermodynamics was to have a huge influence on the future of black-hole theory and would shortly lead him into his second major scientific confrontation with another physicist.

By early 1973, Hawking and Penrose were beginning to use thermodynamics as an analogy for what was happening in a black hole. Scientists often do this: an everyday model helps them to understand situations as bizarre as those found in a singularity. However, a young researcher named Jacob Bekenstein, working at Princeton University, was taking things a lot further. He was not content to use thermodynamics as an analogy, but instead was applying its precepts literally. And he was coming up with some very interesting results.

When Hawking discovered Bekenstein's work, he was incensed. He had been using thermodynamics as nothing more than a model for what was going on and believed it totally ridiculous to take it further and actually
apply
it to black holes. Together with his old friend from Cambridge, Brandon Carter, and the American relativist James Bardeen, he published a paper in the scientific journal
Communications in Mathematical Physics
that attempted to disclaim the suggestion. The argument raged in the scientific press and across the Atlantic for many months. Hawking was becoming more and more irritated by what he saw as Bekenstein's absurd notions. In reply to a paper that Bekenstein published, Hawking, Carter, and Bardeen responded with their own, titled “The
Four Laws of Black Hole Mechanics.” Both papers were later shown to be incomplete.

Most physicists sided with Hawking and his coauthors, but Bekenstein was not put off by the massed ranks of the scientific community ranged against him. Years later, he said of the confrontation:

In those days in 1973 when I was often told that I was headed the wrong way, I drew some comfort from Wheeler's opinion that “black hole thermodynamics is crazy, perhaps crazy enough to work.”
4

Hawking continued to think that Bekenstein's notion was simply crazy—at least for a while. What brought about the change was a series of events that would lead him to a far more important conclusion about black holes and propel him to the forefront of theoretical physics. But that was half a year away, and in the intervening period the arguments continued.

Meanwhile, Hawking was finding the mathematics of the work increasingly difficult to deal with. The equations for interpreting the physics of black holes are amazingly complex, and by this stage of his illness he could use neither paper and pen nor a typewriter. Instead, he was forced to develop techniques for keeping such information in his mind and ways of manipulating equations without being able to write them down. Such a feat has been described by one of Hawking's friends and collaborators, Werner Israel:

[The] achievement is as though Mozart had composed and carried an entire symphony in his head—anyone
who saw the lines of complex mathematics covering the blackboard like musical staves at a recent seminar would have appreciated the comparison.
5

Hawking has the great advantage of possessing a superb memory. In his book
Beyond the Black Hole: Stephen Hawking's Universe
, John Boslough recounts an incident that demonstrates Hawking's ability to retain detailed information in his head:

One of Hawking's students told me that, while driving him to London for a physics conference once, Hawking remembered the page number of a minor error he had read in a book years before.
6

Another anecdote describes how a secretary who worked for Hawking was amazed when he had once recalled, twenty-four hours later, a tiny mistake he had made while dictating—from memory—forty pages of equations. Hawking is not unique in having this talent. In 1983, he dazzled students at a Caltech (California Institute of Technology) seminar when he dictated a forty-term version of an important equation from memory. As his assistant finished writing the last term, his colleague, Nobel laureate Murray Gell-Mann, who happened to be sitting in on the talk, stood up and declared that Hawking had omitted a term. Gell-Mann was also working from memory.

Despite his disabilities, by the early 1970s Hawking was beginning to travel extensively. His status as a physicist had grown with his work in collaboration with Penrose, and he
was frequently invited to deliver talks and address seminars around the world. At the same time as his scientific reputation was building, Hawking's image as a determined fighter, who would go to any extreme to be treated as a normal human being, was spreading far beyond Cambridge.

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