Stephen Hawking, His Life and Work

by Kitty Ferguson

  Stephen and Lucy Hawking took the opportunity of this well-publicized trip to announce that they would be co-authoring a children’s book. George’s Secret Key to the Universe was the first of their books together. It featured not only the space adventures of its young hero George and his next-door neighbours, the scientist Eric and his daughter Annie, and Cosmos, a supercomputer, but also some of the other issues that concerned Hawking. Confronted with the pollution in Chinese cities, he had expressed his worry that Earth might ‘end up like Venus, at 250 degrees centigrade and raining sulphuric acid’.25

  In the ‘George’ books, Lucy actually did give people like the interviewers who had annoyed her something of what they had been hoping for. George’s Key to the Universe and George’s Cosmic Treasure Hunt,26 the first two in what we may hope will be a series, are delightful and instructive, and also offer an insight into the personalities and lives of Hawking and his family. The physicist Eric is unmistakably Hawking, imagined without his disability. His passion for physics and insistence on sharing it, his insatiable curiosity, his single-minded devotion to his work, his love of children – all are there. I am told that the wonderful, redoubtable character, George’s grandmother Mabel, with her selective deafness, is recognizably a portrait of Hawking’s mother Isobel. When George finds himself at a high-level physics conference and dares to raise his hand and ask a question, it is a retelling of a Hawking family story: when Robert, Lucy’s older brother, was eight years old, he went with his father to a conference of theoretical physicists. He took a seat in the front row and listened intently, nodding his head, then raised his hand to ask an intelligent question. The description of the thoughtful, serious way the physicists in the book treat George’s question is a tribute to Hawking’s real-life colleagues. The science in the books is Hawking’s science: black holes, Hawking radiation, the information paradox, the search for another planet for humans to colonize.

  Lucy told interviewers that there were several reasons for writing the ‘George’ books. Her own son was ten years old, and she had a nephew as well, Robert’s and his wife Katrina’s son George. George’s Secret Key to the Universe was dedicated to him and William. Lucy wanted to create, with her father, a book that would explain for these children some of the work he had done. She had noticed the interest when children and their parents had gathered around her father at William’s birthday parties, amazed that he was willing to answer their questions and explain his science to them. She had watched him take the time and trouble to give them good, thoughtful, informative answers and also make them laugh. Hawking pointed out that as children most of us start out filled with curiosity and wonder. Anything is possible. That hasn’t changed for him. That’s still the way he feels, and he and Lucy want to encourage that feeling in their young readers.

  Working with her father on the book gave Lucy a chance to see what her father was like at work in his own field, and that, she said, altered their relationship. Though she doesn’t think he has changed much – possibly mellowed – she had never had the opportunity to see this side of him. ‘He has the amazing ability to hold enormous amounts of information in his head, but also to pick out relevant details and make brief comments, which can completely transform your way of thinking.’27 She was awed by how quick and clear-minded he is, and the knack he has for putting things together and having them fit.

  In November 2006 Hawking was once again stressing, in a BBC radio interview, that the future of the human race depends on our colonizing another planet, not in our solar system but orbiting another star.28 He had hopes of going into space himself. A month earlier Hawking had mentioned in an interview that his next goal was to go on a space flight and ‘Maybe Richard Branson will help me’ – which Branson wasted no time before offering to do. There would be a place for him in 2010 on Branson’s sub-orbital space flight venture Virgin Galactic. Paris Hilton and William Shatner would go along. Hawking didn’t expect Branson to get him to another habitable planet, but was sure the future could hold such journeys, and the fictional characters in his and Lucy’s books followed up on just that suggestion.

  Later in 2006, twenty-five thousand people responded in a blog with answers to Hawking’s question, ‘In a world that is in chaos politically, socially and environmentally, how can the human race sustain another 100 years?’ No wonder he was thinking his ideas might actually influence public policy! In his posted follow-up to the blog, he mentioned genetic engineering, this time not as something perhaps undesirable that was going to happen anyway, but with the utopian hope that it might make human beings ‘wise and less aggressive’.29

  On the trip to China with Lucy, Hawking had once again joked about Pope John Paul II’s forbidding scientists to study the origin of the universe, and said he was glad the Pope was unaware of the topic of his talk because he ‘didn’t fancy the thought of being handed over to the Inquisition like Galileo’. The Vatican itself seemed able to overlook comments like that, but Catholic lay leaders had heard the misquotation and flippant remark once too often. In a heated response, Catholic League president Bill Donohue said that Hawking ‘should stop distorting the words of the pope’: ‘There is a monumental difference between saying that there are certain questions that science cannot answer – which is what the pope said – and authoritarian pronouncements warning scientists to back off.’30 The Pope’s statement had, as we have seen, not been an inaccurate description of the state of scientific knowledge at the time he made it, and there was no threat to make anyone fear Galileo’s fate. His words were:

  Every scientific hypothesis about the origin of the world … leaves unanswered the problem concerning the beginning of the universe. By itself science cannot resolve such a question: it requires human knowledge which rises above the physical, the astrophysical, what we call the metaphysical; what is required above all is the knowledge which comes from the revelation of God.31

  Hawking took Catholic League president Bill Donohue’s words to heart. On his visits to the Vatican as a member of the Pontifical Academy, he has not mentioned the incident or Galileo again. Pope John Paul II had acknowledged in a speech in 1992 that the Roman Catholic Church had erred in condemning Galileo, an acknowledgement Hawking had said he hoped would eventually be made, when he visited the Vatican in 1973. It was time to bury the hatchet.

  Zero Gravity

  In April 2007, Hawking undertook an adventure that he hoped would be the first step on the road to a real space flight. This was a flight that offers passengers the experience of weightlessness, zero gravity. No one was certain how his frail body would react. No problem! Hawking took eight turns of weightlessness, four minutes in all, more than anyone had expected, except, perhaps, himself. ‘I could have gone on and on!’ he said.32 Four physicians and two nurses, who monitored Hawking’s blood pressure, cardiac readings and blood oxygen levels throughout the flight, agreed.

  A company called ‘Zero Gravity’ provides these flights. Here’s how it works: The plane follows a parabolic, rollercoaster path. As the plane climbs, passengers feel almost twice the pull of gravity they normally feel on Earth. Near the top of the parabola, they feel they are in free-fall for about twenty-five seconds. The course is then repeated, in Hawking’s case eight times.

  Hawking had a second motive for taking this flight, and, he hopes, his upcoming space flight – spreading his conviction that colonizing other planets is the only hope for an extended future for us.

  It will be difficult enough to avoid disaster on planet earth in the next 100 years, let alone the next 1000 or million. The human race shouldn’t have all its eggs in one basket or on one planet. Getting a portion of the human race permanently off the planet is imperative for our future as a species.33

  There is, he insisted, a huge future mass market for space-oriented services in tourism. ‘We need to engage the entrepreneurial engine that has reduced the cost of everything from airline tickets to personal computers.’34

  Hawking’s third motive for taking the
flight was to encourage other disabled people to get out and try things like this. If he can do it, so can others. While that may not be true when it comes to theorizing about the origin of the universe, when it comes to adventures like weightlessness, why not? The answer that most immediately comes to mind is, of course, the price.

  Itinerant physicist

  2008 was a phenomenally busy year of travel for Hawking, and even more so for his valiant personal assistant, Judith Croasdell, whose task it was to make preparatory journeys to reconnoitre, plan the visits with his hosts, and make all the necessary on-the-spot arrangements. She had been told when she was hired that ‘the personal assistant does not travel’. That may have been true for other PAs, but not for Judith.

  In January the destination was Chile; the occasion a scientific meeting in Valdivia to celebrate the sixtieth birthday of Chile’s most distinguished physicist, the charismatic Claudio Bunster. Bunster had been responsible for Hawking’s visit to Chile and Antarctica ten years earlier. From Chile, braving the difficulty of taking Hawking in his wheelchair to a remote part of the world with dauntingly uneven terrain where disabled access was only just beginning to be considered an important addition, his entourage flew with him to Easter Island. For Judith Croasdell, who had lived in the Southern Hemisphere in the Pacific islands herself for many years and been a student of Pacific history, this trip was ‘the Holy Grail’.

  In May it was South Africa. In Cape Town, Hawking visited the African Institute for Mathematical Sciences (AIMS), an institute for postgraduate study that draws top students from all over Africa and supports the development of mathematics and science across the continent. Hawking’s friend and colleague Neil Turok, the founder of AIMS, helped organize that trip. Hawking met Nelson Mandela and launched the Next Einstein Initiative, a programme at AIMS that Hawking said, in his lecture, he hoped would nurture ‘An African Einstein’.

  In September, hosted by the University of Santiago de Compostela, Hawking touched down in that famous, beautiful Spanish pilgrimage city, to receive the Fonseca Prize, an award that celebrates outstanding individuals in the communication of science to the general public. Judith Croasdell remembers that ‘it was a tough trip, with high expectations and a huge press conference. The press conference was far too long, the press asked far too many questions (over forty questions for Stephen to choose from). Stephen answered about fourteen – which was a lot.’ Lucy accompanied him on this journey, to publicize the Spanish edition of George’s Secret Key to the Universe.

  With far-flung travels evidently on his mind that year, in his lecture at Caltech Hawking was a little less pessimistic about the possibility of travelling through a wormhole to another universe. He pointed to a new possibility, black holes in the extra dimensions of space-time. Light wouldn’t propagate through the extra dimensions, only through our familiar four, but gravity would affect them and be much stronger than what we experience. That would make it easier for a little black hole to form in the extra dimensions.

  In this lecture, while giving background about black holes in general, he described Hawking radiation in a different way. He wasn’t reneging on the version involving particle pairs, it was just an alternative way of thinking about it. If a particle is in a very small black hole, you know with fair accuracy where it is. Because of the uncertainty principle, the more certain you are about its position, the less certain you are going to be about its speed. So the smaller the black hole the more uncertainty about a particle’s speed. It could even be more than the speed of light, and that would allow the particle to escape from the black hole. In this description, Hawking radiation does come from inside the black hole.

  Could you possibly fall into a black hole and come out in another universe? He thought that might be possible. He had not given up on the idea of wormholes. But you couldn’t come back again, so he, personally, is not going to try it, in spite of being one of the most intrepid and eager-to-travel people in the world.

  fn1 ADS stands for anti-de Sitter; CFT for conformal field theory.

  19

  ‘I’ve always gone in a somewhat different direction’

  ‘IT IS ASTONISHING that bold predictions of events in the first moments of the universe now can be confronted with solid measurements,’ exclaimed WMAP’s principal investigator, Charles Bennett, in March 2008.1 ‘Fifth year results’ had shown that the WMAP satellite’s data was placing tighter constraints on inflation theories while supporting inflation in general. At the same time, WMAP had discovered something no one had predicted – a mysterious break in the overall random distribution of the temperature variations in the CMBR – a ‘cold spot’.2 All that could be said definitively about it was ‘watch this spot’, but so far none of the suggested explanations cause a problem for inflation theory.

  The race to find experimental and observational evidence to confirm what had been theoretical for a long time was happening not only out in space but also on the ground – and deep under it. With the switch-on of the Large Hadron Collider at CERN, on 11 September 2008, expectations were running high that this long-awaited instrument could at last reveal the Higgs boson.

  Hawking v. Higgs

  Peter Higgs had proposed the Higgs boson’s existence in 1964 and seen it become part of the standard model of cosmological theory. At a press conference in 2008 he reacted heatedly – ‘launched an attack’ was the way the Sunday Times headline put it3 – to a comment Hawking had made in an interview on the BBC.

  The less than cordial relationship between Higgs and Hawking dated back to 1996. Hawking had published a paper in which he had stated that it would be impossible to observe the Higgs particle. By 2000 he had not been proved wrong. When the Large Electron Positron (LEP) experiment at CERN was finally closed down that year without having produced definitive proof of the Higgs particle, Hawking raked in $100 on a bet with colleague Gordon Kane at the University of Michigan. Another Hawking bet against the Higgs particle was still unsettled, awaiting the end of similar experiments at Fermilab near Chicago. The exchange between Hawking and Higgs pushed the usual limits of heated scientific discussions when Higgs, at a dinner in Edinburgh in 2002, said of Hawking that it was ‘difficult to engage him in discussion, so he has got away with pronouncements in a way that other people would not. His celebrity status gives him instant credibility that others do not have.’ Hawking countered with: ‘I would hope one could discuss scientific issues without personal attacks’, and Higgs privately made peace by explaining to Hawking the context of his comments. Hawking said he was not offended, and things settled down, but Hawking never swerved from his opinion that the Higgs particle was beyond the reach of any experiment.

  In a press conference shortly before the switch-on date for the LHC in September 2008, Hawking opened old wounds with the comment that he thought ‘it will be much more exciting if we don’t find the Higgs. That will show something is wrong, and we need to think again. I have a bet of $100 that we won’t find the Higgs.’4 Higgs reacted with disparaging remarks about Hawking’s work: ‘From a particle physics, quantum theory point of view, you have to put a lot more than just gravity into the theory to have a consistent theory and I don’t think Stephen has done that. I am very doubtful about his calculations.’5 Hawking had argued there might be more interesting outcomes from the LHC, such as the discovery of some of the supersymmetric partners. ‘Their existence would be a key confirmation of string theory,’ said Hawking, ‘and they could make up the mysterious dark matter that holds galaxies together. But whatever the LHC finds, or fails to find, the results will tell us a lot about the structure of the universe.’6 The Sunday Times comment that ‘their spat is likely to send shockwaves through the scientific Establishment’ was something of an overstatement, but the 79-year-old Higgs could not be blamed too much for being passionately eager for his theory, finally, to be confirmed.

  Hawking had other fish to fry in the LHC. He had mentioned in his most recent Caltech lecture that he thought it might be poss
ible to observe microscopic black holes resulting from collisions in the Collider. If so, these black holes should be radiating particles in a pattern we would recognize as Hawking radiation.7 He might get a Nobel Prize.fn1 He had also mentioned again that fluctuations in the CMBR can be thought of as Hawking radiation from the inflationary period of our universe, now frozen in.

  Unfortunately for Higgs and Hawking and a lot of other people, just nine days after the Large Hadron Collider was switched on, CERN had to switch it off again. A faulty electrical connection allowed a helium leak into the tunnel housing the collider and caused the superconductor magnets that steer sub-atomic particles around the collider to malfunction. It took a year to get the LHC back in action.

  The Higgs particle, at the time of this writing, continues to be elusive. As of late February 2011, after a short winter maintenance break, researchers were gearing up for yet another try. ‘We know that we will either discover the Higgs particle or rule it out, and in either case it will be a big result,’ Sergio Bertolucci, CERN’s Director for Research and Scientific Computing, said. ‘Of course, it’s more difficult to sell as a big result if we don’t find it, but if the Higgs doesn’t exist, there must be something else in its place.’8

  The Time Eater

  That September of 2008 when Higgs and he were renewing their altercation, Hawking had the honour of unveiling a harrowingly beautiful addition to the streetscape in the old centre of Cambridge. Corpus Christi College, which has the most ancient court in Cambridge, became home to this newest phenomenon, a very large mechanical clock on the corner where Bene’t Street meets King’s Parade.9 It has no hands but tells the seconds, minutes and hours with what appear to be small flashing blue tear-shaped lights moving in concentric circles around a gleaming clockface that is five feet in diameter. Plated in pure gold, the huge face is designed to look like ripples and troughs radiating out, as if a stone had dropped into a pond of molten metal. The ripples represent the explosion of the Big Bang, sending out pulsating gold.