Jane was caught up in a social whirl and the Hawkings entertained almost constantly. It is rare in the Cambridge colleges, with the notable exception of Clare Hall, for spouses to be nearly as much a part of the social scene as Jane experienced at Caltech. She found the change exhilarating, if also a little exhausting. In addition to new local friends, there were visitors from abroad, friends and family including Jane’s parents and Stephen’s mother and aunt. Stephen’s sister Philippa visited from New York, where she was living. The Hawking home, so convenient to the campus, was the site of frequent parties for the Caltech Relativity Group.
The spontaneity and directness of Californians were a surprise and, to Jane, a pleasant change from the diffidence and, sometimes, outright avoidance she and her husband were used to encountering in England. It was not easy, because of Stephen’s speech problems, for those who did not know them well to carry on a conversation with the pair of them, but Californians seemed more than willing to try. Stephen Hawking was becoming an international celebrity in his field when he arrived at Caltech and he was, accordingly, given star treatment. To be fair, had he been introduced to Cambridge similarly for the first time, his and Jane’s reception in University circles might have been characterized by some of the special attention they experienced in Pasadena.
For an academic taking a sabbatical year abroad, the time spent away from home is often not only an enormous boost to his or her creativity and intellectual energy, but also a watershed for other members of the family. So it was with the Hawkings. An eight-year-old computer-wiz friend got Robert excited about the field that would eventually become his career, information technology. Another faculty wife invited Jane to attend an evening choral class that met each week to sing through a major choral work – Jane’s first introduction to an avocation that would become her passion and engage her for many years.
Hawking had an air-conditioned office, and ramps sprang up all over the Caltech campus. He basked in the company of other eminent researchers and dined as an honoured, delighted guest in the student ‘houses’. The California Institute of Technology was and is one of the greatest centres in the world for the study of physics and physics research. It is a smaller institution than Cambridge or Oxford, but the faculty includes many of the world’s most outstanding academics, undisputed leaders in their fields. For Hawking, new colleagues and stimulating ideas abounded, drawing his interest to areas he hadn’t explored and to fresh ways of approaching the problems he was already working on. It was here that he first met Don Page, then a Caltech graduate student, who would play a large role in the Hawkings’ future. Page and Hawking wrote a paper that year which suggested that the explosion of primordial black holes might be observed as gamma ray bursts.26 Legendary arch-rivals Richard Feynman and Murray Gell-Mann were also at Caltech, and Hawking attended their lectures. Both were cutting-edge particle physicists, not cosmologists, but Hawking was finding more and more need for expertise in particle physics in his study of black holes, and here was a priceless opportunity. He would soon be employing Feynman’s idea of ‘sums-over-histories’ in a new way as he explored possibilities for describing the origin of the universe. Jim Hartle, whom Hawking had met in Cambridge and who was at the University of California-Santa Barbara, spent some time at Caltech that year, and he and Hawking developed the description of Hawking radiation discussed in Chapter 6.27
Hawking didn’t spend the entire year, uninterrupted, in Pasadena. Just before Christmas he joined his friend and colleague George Ellis to attend a conference in Dallas, and in April he was invited to Rome to receive, from Pope Paul VI, the Pope Pius XII medal, awarded ‘to a young scientist for distinguished work’. Hawking was eager to see the document in the Vatican Library in which Galileo had recanted, under extreme pressure and threat of torture, his discovery that the Earth goes around the sun. Hawking took the opportunity to lobby for a formal apology to Galileo, whom the Catholic Church had treated so badly three and a half centuries before. That apology would not be long in coming.
It was in California that Hawking began to think seriously about a problem which would set him at odds with some of his colleagues for many years: the loss of information in black holes. We will examine later what ‘information’ means in this context. For now, think of it as information having to do with everything that went into the making of the black hole when it formed and everything that has fallen in since. How irrevocable is this loss? What might it mean for our ability to understand the universe and make predictions? Could it really represent the breakdown of physics? That was the title he gave a paper he wrote that year – ‘Breakdown of Physics in Gravitational Collapse’. When it finally appeared in November 1976, he had changed the title to something less shocking, unless you stopped to think about it: ‘Breakdown of Predictability in Gravitational Collapse’.28
And, of course, there was Kip Thorne, the dear friend and colleague who had been instrumental in making the whole visit possible. Thorne and Hawking put their signatures (Hawking’s thumb print) to a document recording their first famous bet, about whether the binary star system Cygnus X-1 contains a black hole.
Penthouse v. Private Eye
The pre-history of Thorne’s and Hawking’s bet began in 1964, before John Wheeler had even coined the name black hole. That year Yakov Zel’dovich and his graduate student Oktay Guseinov at the Institute of Applied Mathematics in Moscow began combing the lists of many hundreds of binary star systems that astronomers had previously observed and catalogued. They were looking for stars so extremely massive and compact that they are unlikely to be anything but black holes. The search for black hole candidates had begun, and it was no straightforward undertaking. Such candidates are, by nature, invisible to an optical telescope.
In order to understand what binary star systems are and why they are good places to look for black holes, picture a scene described by John Wheeler. In a dimly lit ballroom, the women are all dressed in white gowns. Some of the men are also dressed in white, but a few of them are in black formal attire. Watching the couples waltz, from a balcony above, we know there are two people in each pair, but in some cases we can see only one of them, the woman in white.
A binary star system consists of two stars circling one another, as the man and woman in one of Wheeler’s couples do. In some binary systems, only one star is visible. How do we know that there are two stars? In the ballroom, by watching how the visible woman moves, it’s fairly obvious that she must have a partner. Likewise, by studying the movement of some stars, it is possible to conclude that they are not alone out there.
Seeing a star apparently alone but moving as though it has a partner does not always signify a black hole. The invisible companion might be a small, dim, low-temperature star – a white dwarf, or a neutron star. Calculating the mass of such stars is complicated, and mass is a vital statistic when you’re trying to determine whether something is a black hole or not. Suffice it to say that, again, this was information that astronomers in the 1960s were beginning to find ingenious ways to glean from the movements of the visible star.
In 1966, Zel’dovich and another colleague, Igor Novikov, decided that identifying strong black hole candidates would require using both optical telescopes and X-ray detectors. The observation of X-rays indicates a source of considerable energy powering their emission, and having material fall towards a black hole or neutron star is one of the best ways known to liberate energy. In a binary system, that is what happens when the very compact star or black hole pulls material away from its companion star. So researchers looked for binary systems where one partner shows up brightly in the visible part of the spectrum but is dark in the X-ray part; while the other partner is dark in the visible part of the spectrum but bright in the X-ray part.
Cygnus X-1 was a very promising candidate. Here was a binary system where an optically bright but X-ray dark star orbits with an optically dark but X-ray bright companion. This system is in our galaxy, about 6,000 light years from Earth. The t
wo stars complete one orbit in 5.6 days. An optical telescope reveals what seems to be a blue giant star, too dim to be detected with the naked eye. Studies of the Doppler shift in its light show that it must have a companion. Cygnus X-1 is that companion. It can’t be seen at all with an optical telescope, but it is one of the brightest objects in the X-ray sky. The X-ray emission fluctuates violently and chaotically, as expected when matter falls towards a black hole or neutron star. Cygnus X-1’s mass is at a minimum 3 solar masses, probably greater than 7 solar masses, and most likely about 16 solar masses. In December 1974, such uncertainty in calculations of its mass made the Hawking–Thorne bet possible. Cygnus X-1 was an excellent black hole candidate, but experts were only about 80 per cent certain that it was a black hole and not a neutron star.
The bet document laid out the terms: If Cygnus X-1 turned out to be a black hole, Hawking would give Thorne a one-year subscription to the magazine Penthouse. If it turned out not to be a black hole, Thorne would give Hawking a four-year subscription to Private Eye. Hawking called his surprising bet against Cygnus X-1 being a black hole an ‘insurance policy’. ‘I have done a lot of work on black holes, and it would all be wasted if it turned out that black holes do not exist. But in that case, I would have the consolation of winning my bet.’ The bet document was framed and hung on the wall of Thorne’s office at Caltech, awaiting the advancement of science.
Sadly, as the year in California approached its end, the feelings of depression, inadequacy and low self-esteem that had plagued Jane back in Cambridge caught up with her again. She began to reassess the social whirl of that year in Pasadena and view it as a sort of frenzied escapism from these problems. She felt she had fallen easy prey to the women’s liberation movement’s insistence that a woman who had no job outside her home should consider herself a failure, lacking in personal fulfilment.29 Jane concluded this was indeed the prevalent feeling among unemployed faculty wives she had met. Excursions with them to art museums and galleries and plays now seemed only the sad, kindly attempts of these women to make up for the bleakness of their lives and hers. A thoughtful and discerning friend, recognizing Jane for the remarkable woman she was, and perhaps sensing that she was not capable of recognizing this herself, gave her a pearl brooch on the day that Stephen Hawking was awarded his Papal medal, saying that she, Jane, should be given something too.30
8
‘Scientists usually assume there is a unique link between the past and the future, cause and effect. If information is lost, this link does not exist’
BACK IN CAMBRIDGE after their sojourn in california, the Hawkings settled into their new home in West Road.1 For Stephen, after a year in an electric wheelchair that could move fast and be used both indoors and out, there was no going back to an old-fashioned model. His request to the UK Department of Health for a chair like the one he’d had in California was rejected. The Hawkings drained their savings to purchase it themselves.
In this new vehicle, the daily journey to the DAMTP in Silver Street took about ten minutes, not by the shortest route but by a more pleasant and less-trafficked one. He followed a curving tree-lined footpath through King’s College that took him across the ‘Backs’ past meadows with grazing cows and immaculately mown lawns, crossing the River Cam by a hump-backed stone bridge behind King’s College Chapel. From there he had a choice. He could use a side entrance from King’s and, by way of a not heavily used back street called Queens’ Lane, pass in the shadow of the towering medieval gates of Queens’ College to arrive at Silver Street. Or he could exit King’s by its main front gate into busy King’s Parade, and then turn right to reach Silver Street. Either way, the hazardous crossing of this narrow, busy thoroughfare provided a modicum of risk and excitement to climax an otherwise peaceful journey. Around the back of his building was his ramp. He would time his arrival for about 11 a.m. Hawking’s new graduate student assistant, Alan Lapades, sometimes made the journey with him, but often Hawking went on his own, the state-of-the-art wheelchair giving him optimum independence.
By the autumn of 1975, Hawking had completed the six years of his Caius Fellowship for Distinction in Science. Though he couldn’t lecture, he was a very good mentor, willing to spend so much time in discussion with his students that some colleagues wondered how he ever got his own work done. The University of Cambridge put an end to rumours circulating that he might emigrate permanently to the USA by offering him a ‘readership’ and also a secretary, Judy Fella. Judy was a vivacious and rather glamorous addition to the DAMTP and a godsend to both Stephen and Jane. His having his own secretary relieved Jane of the burden of doing all Hawking’s scheduling and travel bookings. Jane turned once again to her neglected thesis and, following up on her new musical interest, began voice lessons.2
In the summer of 1975, BBC television lorries lumbered into the Hawkings’ West Road forecourt and snaked cables into the house to film Stephen for a documentary, The Key to the Universe, moving to Silver Street to film a seminar in the DAMTP. Media invasions such as this, which would happen many times in the future, ran roughshod over other interests and priorities of colleagues, students, staff and family. Over the years it would become an annoyance, but the first few times it was very exciting.
Jane’s plan of having live-in student assistants was working well. Hawking was eager for Don Page, whom he had met at Caltech, to come to fill that position. Page, who was finishing his Ph.D. and applying for postdoc posts, was a close friend and an extremely promising physics colleague. When Gary Gibbons was invited to Munich for a year, that freed funds to hire Page as Research Assistant. Later, a NATO fellowship would pay him. In autumn 1976, this unusually tall young man with a powerfully resonant speaking voice joined the West Road household.
For Hawking, an agnostic bordering on atheism, Don was an unexpected choice – intellectually brilliant, scrupulously moral, devoutly and outspokenly religious. He would not stick to physics topics on journeys to and from Silver Street but often veered off into discussions of what he had read in the Bible that morning. Stephen parried with friendly sceptical banter but respected Don’s opinions and faith. Don would remain a personal friend and a highly valued academic collaborator long after his student assistantship was over.
With Judy Fella at the office and Don Page at home, some of the responsibility for Stephen was off Jane Hawking’s shoulders. For the first time in many years, Stephen travelled without her, in the summer of 1977, when Page accompanied him on a revisit to Caltech lasting several weeks.
It was about this time that Hawking and other younger Fellows were invited to come to London for Prince Charles’s induction into the Royal Society. The prince was intrigued by Hawking’s wheelchair, and Hawking, twirling it around to demonstrate its capabilities, carelessly ran over Prince Charles’s toes. Soon rumour had it that running over toes was not always accidental, and eventually it would get around that one of Hawking’s regrets in life was not having an opportunity to run over Margaret Thatcher’s toes. People who annoyed him, it was said, found themselves a target. ‘A malicious rumour,’ insists Hawking. ‘I’ll run over anyone who repeats it.’3
In the autumn of 1977, just two years after his ‘readership’ began, the University of Cambridge promoted Hawking to a chair in gravitational physics, with a welcome rise in salary. He was now a ‘professor’, a distinction much more rarely achieved at Cambridge and most English universities than in an American one.
It was that December of 1977, when Jane joined the choir of St Mark’s Church in Barton Road for the Christmas season of special music, that she first met a young man named Jonathan Hellyer Jones, who was the organist there. Jonathan was a gifted musician, younger than Jane and Stephen by a few years. He had recently lost his wife to leukaemia after only one year of marriage. The Hawking home became a haven for him. Both Jane and Stephen were emotional supports, but Jonathan also more than pulled his own weight in the household – sitting at the piano teaching seven-year-old Lucy, and volunteering to help wit
h Stephen’s physical needs. Jane joined the St Mark’s congregation. She also was at last able to find the time to begin working seriously on the final chapter of her thesis.4
Perhaps it was inevitable that this young man, intimately and generously involved with the family, a godsend to Jane as she struggled to keep up with her tasks as caregiver, homemaker, Ph.D. student and mother, and sharing her faith and her love of music, would become more than a helpful supportive friend. Jane, with characteristic honesty, did not keep it a secret from Stephen when she and Jonathan developed a romantic attachment. Hawking apparently accepted this, saying nothing except that, as Jane has written, ‘he would not object so long as I continued to love him’.5 After that, the subject was rarely mentioned between them, and Jane’s relationship with Jonathan remained platonic for a long time. They chose ‘to maintain our code of conduct in front of Stephen and the children, suppressing displays of close affection’. They did not move out to live together. ‘Jonathan and I had struggled with our own consciences and decided that the greater good – the survival of the family unit, Stephen’s right to live at home within that family unit and welfare of the children – outweighed the importance of our relationship.’6 Their secret was so well guarded that only a small circle of family and friends were aware of that relationship, and whatever grief Jane and Jonathan may, or may not, have caused him, Hawking kept that to himself.7
In the autumn of 1978 Jane was pregnant again. With not only Don Page and Judy Fella but also Jonathan on board, she decided to set herself a deadline for finishing her thesis before the baby was born in the spring. It was now or never. In the winter she set that work aside only briefly to organize a charity concert to raise funds for the newly formed Motor Neurone Disease Association. Stephen was a patron. Jane was beginning to be a presence in the music world of Cambridge.8
Stephen Hawking, His Life and Work Page 12
