Stephen Hawking, His Life and Work

by Kitty Ferguson

  I agreed to take a look at this material and soon found myself completely absorbed. For Ann I produced glosses in the margins: ‘This is what he is saying …’, or ‘too technical’, or ‘understandable’, or ‘already said this on p. 33’, and I created a map showing how the various pieces, and pieces of pieces, could be rearranged and linked in such a way that they would be chapters in a book. Ann Harris took me on board with the brief of ‘helping Hawking make the book simpler so that ordinary people can understand it’. The ‘ordinary people’ was no problem. I was one of them myself.

  As it turned out, Stephen Hawking was ahead of both Ann Harris and myself. He had a perfectly good plan of his own for how this book would fit together. The nonlinear organization was intentional. There would be separate chapters, each on its own topic, that could be read in any order after mastering a small core of essential material. My task became to help smooth out the un-evenness in the difficulty levels of the chapters, to point out where some of them needed work to bring them to a level accessible to intelligent general readers. Hawking decided to use the opportunity to stress again some of his opinions on controversial issues beyond the realm of his science. After several months communicating by e-mail, we worked together for two weeks in his office in Cambridge. Also on board was a fantastic illustrator, Philip Dunn, from Book Laboratory and Moonrunner Design. At first I worried about the scientific accuracy of some of his drawings, but, in the end, his pictures made Nutshell the most innovatively illustrated of all Hawking’s books.

  Not Silver Street

  By the year 2000, there had been a dramatic change for the DAMTP. Though the new, ultra-modern complex called the Centre for Mathematical Sciences would not be complete until 2002, the DAMTP had already moved there from the old building in Silver Street when I came to work with Hawking on The Universe in a Nutshell. Instead of crossing the Backs and the River Cam to reach the new complex from where I was staying at Clare Hall, I walked in the opposite direction, away from central, ancient Cambridge, through an upscale residential section of town, in the direction of the New Cavendish Labs but not quite so far. The new Centre for Mathematical Sciences was still a work in progress but it already looked like something out of Star Trek, except for the ‘green’ (literally – turf-covered) roof of one section. No longer could I walk straight in. I had to be fetched from Reception by Hawking’s personal assistant, whom I hadn’t met before, Karen Simes.

  Hawking’s new office was a vast improvement over the old one in Silver Street. It was spacious, carpeted, modern, light-filled from two walls of windows. A ‘corner office’. There was room not only for his desk, computers, bookcases and a blackboard, but also for a plush sofa, chairs and a coffee table for guests, all in muted designer colours. Marilyn Monroe surveyed the scene from a framed, pastel portrait, much more upmarket than the one I remembered hanging in Silver Street. Most of the photographs on the desk and shelves were of William, Lucy’s little boy, Hawking’s grandchild. The windows overlooked lawns two storeys below and the older, well-to-do residential area surrounding the complex. This view was not to last, I was told, for the Centre was still being built and would soon include another ‘pavilion’ a few yards outside the windows. Nevertheless, the outlook was a considerable improvement over the old car park and the blank brick wall.

  It seemed a serious loss, however, that the only room in the new complex that was vaguely comparable to the common room in Silver Street was a large dining facility a good distance down corridors and across outdoor ramps and bridges from Hawking’s office. Its size and remoteness meant that it didn’t lend itself as the old shabby common room had to writing equations on tables and having impromptu informal seminars over tea or coffee at 4 p.m. That situation would have to be remedied.

  The building was nevertheless impressive in its technical marvels. Window blinds ground up and down without human intervention in response to the intensity of the light. They also went down at night because of complaints from neighbouring homes that the size and brightness of this ultra-modern monstrosity gave the impression that we need no longer wonder whether extraterrestrial life exists … it had landed, in force, across the street. The building also ‘breathed’ occasionally; papers fluttered as air was drawn automatically through vents, doors and windows.

  In spite of all this modernity and innovation, the clicking sounds of the little box Hawking held in his hand, the flitting words on the screen, the synthetic voice, were exactly as I remembered them. Some of the nurses were familiar faces.

  Though I had been communicating with Hawking by e-mail for several months before coming back to Cambridge, it was a relief to find, in person, that neither the move to the new building nor his continuing world travels and celebrity, nor becoming a grandfather, nor changes in his personal life, had kept him from going right ahead with the work he loved and to which he had devoted so many years of unexpected and triumphant survival. The boss was still awake. Our conversations were not, of course, like ordinary conversation. Using his hand-held device, he would send the cursor on the screen off on a hell-for-leather pursuit of each single word across the half-screens and lines full of words, and finally attempt to capture the word itself, often missing it, and the process would start over again. I knew I must resist the temptation to complete sentences for him, even when I could tell what he was going to say. That would be impolite, and he might very well go right ahead and finish the sentence anyway. So I waited and watched, and silently rooted for the cursor to capture the word. ‘Come on! … there! … got it … oh no!’ I found myself pumping my fist and stopped. Were there any expletives programmed into his phrase lists? I don’t know. After only a few minutes of frustration at the beginning of the two weeks, I calmed down. It was necessary to take his cue, be patient and allow it all to happen his way. He wasn’t frustrated – or maybe he was, but he couldn’t show it.

  Our work together on The Universe in a Nutshell consisted in the main of my pointing out paragraphs, sentences and sometimes larger pieces of the manuscript that I thought needed to be stated in simpler language. I had prepared alternative wording, but in all instances, though he listened to my suggestions, he insisted on making the changes in his own words. Sometimes my comment, ‘I think that sentence is too difficult, Stephen’, would bring forth the vintage Hawking smile, a storm of clicking and flickering words and the reply, ‘It seems clear to me.’ But he would set to work remedying the problem, laboriously translating the language of theoretical physics into the language of ‘ordinary people’. Only occasionally, when the translation still didn’t seem simple enough, did I resort to saying, ‘I’m sorry, but I can’t understand that’, even if I thought maybe I could. He would reply, ‘I’ll make it simpler then’, and he did.

  One of the most interesting suggestions he was making in The Universe in a Nutshell was that we may live on a four-dimensional surface within a higher dimensional spacetime. Such a surface had been dubbed a ‘brane world’.

  If we lived in such a situation, everything in our own four-dimensional brane world, what we normally call ‘the universe’ – matter and light, for instance – would behave just the way we have found it does in the universe we know, with the exception of gravity. Gravity (thought of as the curved spacetime of general relativity) would spread throughout the higher dimensional spacetime, and because this was so, we would find gravity behaving oddly. For one thing, it would grow weaker with distance more rapidly than we have experienced it doing.

  Here there was a hitch, for if the gravitational force fell off more rapidly with distance, the planets couldn’t orbit as they do. They would fall into the sun or escape to interstellar space. We don’t find that happening. However, suppose the extra dimensions didn’t spread too far but ended on another brane world fairly near our home brane world – a shadow brane world that we couldn’t see because light, as we’ve said, would be confined to its own brane world and not spread through the space in between brane worlds. It might be only a millimetre away f
rom us but undetectable because that millimetre is measured in some extra spatial dimension. Imagine an analogy in a two-dimensional world: there are insects on a piece of paper, with another piece of paper hovering near it and parallel. The insects are unaware of the other piece of paper because they can’t conceive of a third dimension of space. They know only the two dimensions of their piece of paper. If the extra dimensions ended on such a shadow brane world, then for distances larger than the separation between the brane worlds, gravity would not be able to spread out freely after all. Just like the other forces of nature, we would find it effectively confined to our home brane world, and it would fall off with distance just as we expect it to – at the right rate for planetary orbits.

  However, there would be tell-tale clues. For distances less than the separation between the brane worlds, gravity would vary more rapidly, and these variations ought to show up in measurements of the very small gravitational effect between heavy objects placed extremely short distances apart.

  There are other interesting implications: a nearby ‘shadow’ brane world would be invisible to us, because light from that brane world could not spread to ours, but we would feel and observe the gravitational effects of matter on that neighbouring brane. Those effects would be mysterious to us, because they would appear to be produced by sources that we cannot detect at all except through their gravity.

  Is that the explanation behind the ‘missing mass’ and ‘dark matter’ mystery in astrophysics? For stars, galaxies and galaxy clusters to be situated as they are and to move as they do, there has got to be much more matter in the universe than we can observe in any part of the electromagnetic spectrum. Could it be we are observing the gravitational influence of matter in other brane worlds?

  There are other brane world models besides the one involving shadow branes, and speculation about the implications of the models has extended to many subjects which are of enormous interest to Hawking, such as black holes, radiation at the event horizon, black hole evaporation, gravity waves, the relative weakness of gravity in comparison with the other forces of nature, the origin of the universe and its history in imaginary time, inflation theory, the Planck length, and the no-boundary proposal.

  How does the no-boundary proposal look when viewed through brane world glasses?

  Our home brane world would have a history in imaginary time that was like a four-dimensional sphere, that is, like the surface of the Earth but with two more dimensions. So far – if you have read the previous chapters of this book – that ought to sound familiar. The difference is that in the original no-boundary proposal there was nothing ‘inside’ the expanding sphere, the ‘globe of the world’ that Hawking asked us to picture. In the new brane world version that is not the case. Inside the bubble is higher dimensional space, and the volume of that space, as might be expected, increases as the brane world expands.

  In the chronological time we experience, our home brane world would expand with an inflationary phase like that described in inflation theory. The most probable scenario would be one in which it expanded for ever at the inflationary rate, never allowing stars and galaxies to form. But we could not exist in such a brane world, and we do obviously exist. So the anthropic principle compels us to find out whether the brane world model offers other less likely but not impossible scenarios. It does. We find that there are imaginary time histories that could correspond to real time behaviour in which the brane world had a phase of accelerating inflationary expansion only at first but then slowed down. After that, galaxies could have formed and intelligent life evolved. That sounds more familiar.

  The most mind-boggling suggestion having to do with branes had been inspired by our knowledge of holography. Recall Leonard Susskind’s suggestion about the way holography might apply to black holes. In holography, information about what happens in a region of spacetime can be encoded on its boundary. Hawking leaves us with the question of whether we might only think we live in a four-dimensional world because we are shadows cast on the brane by what is happening in the interior of the bubble.

  The work on Nutshell would continue later for several months by e-mail, fine-tuning the editing, but, by and large, those two weeks when I was in Cambridge got the job done. It was exciting work, but it was also tense work. As I exited the car park of the Centre for Mathematical Studies on the final evening, I gave a silent cheer and did, finally, allow myself to pump my fist. We had done it! I had survived. So had Stephen Hawking.

  Dinner at Caius

  On one cold November evening during those two Cambridge weeks, I rode with Stephen Hawking in his van to Caius for dinner. The van stopped where King’s Parade turns into Trinity Street, between the Senate House and Great St Mary’s Church and across from Gonville and Caius College. The nurse who had driven us from the Centre for Mathematical Studies set the brakes, left the headlights burning, and came around to the passenger side to release the heavy harnesses that secured Hawking and his wheelchair where the passenger seat would usually be. I, the only backseat passenger, moved out of her way and waited in the street, since freeing the wheelchair was heavy work and required space to manoeuvre. The ubiquitous Cambridge cyclists dodged with lightning reflexes around me and the van. Soon they were also having to dodge the metal ramp that protruded from the door and allowed Hawking, bundled up against a cold wind, to guide his chair smoothly down on to the pavement.

  He made his way at a slow majestic pace through the Gonville and Caius gate and across three courtyards to the doorway that led to the Hall. After all those years, and all his success in the cause of disabled access, there was still no convenient way for Hawking to get to the Senior Common Room and the Hall of his college. There was space on the tiny lift only for him and his nurse. He instructed me and my husband, who had met us at the gate, how to find our way up by another route. We rejoined him as he threaded his way through the kitchens and other rooms that are not on the tourist circuit, although much of Caius is ancient and beautiful. In the richly panelled Senior Common Room a fire was burning, and Fellows of the college greeted Hawking in a manner that indicated they knew him well and had long ago stopped being surprised, shocked or impressed by his disability or his accomplishments. Some of them have equal claims to fame in their own academic fields, though not so much international notoriety. He is to them simply Stephen.

  After sherry, everyone proceeded to the Hall and took places at High Table, a step above the level of the long tables crowded with noisy undergraduates – for Caius is a college that still makes a serious commitment to dining in Hall. Graduate students of the college ate somewhat more calmly in the minstrels’ gallery, sans minstrels. Amidst the pleasant clink of forks and knives on college china, the rumble of young voices, occasional outbursts of shouts and boisterous laughter, and the more well-modulated voices of the Fellows, we ate and drank a fine wine from the college cellars. Stephen Hawking’s nurse wrapped his huge bib around his chest and fed him, while he clicked on his hand-held device and, through his computer, discussed international politics with my husband.

  The Hall is hung with portraits of eminent fellows of Caius. Near the centre, prominently displayed, is a modern painting of Hawking. For centuries, men (and, more recently, women) have gone from this college and from those long, rowdy tables to teach, to continue research, to make money, to change the world. We ate, as they had, with this odd amalgam of the new, the antique, the remarkable, the ordinary, the wet-behind-the-ears, the venerable. The occasion was a little like dining at summer camp in a room that just happened to be hundreds of years old and incongruously beautiful. In this generation, Caius has taken in its stride one of the most extraordinarily different men of our time – whom everyone there seems to regard as just another camper.

  During the two weeks I spent in Hawking’s office in the autumn of 2000, working with him on The Universe in a Nutshell, I often would arrive at the DAMTP before he did and wait at the curved modern desk between his office door and the bridge from the lift i
n this supermodern ‘pod’. Each day when the lift doors opened and his chair emerged, it seemed to me there was a tiny but profound alteration in the feel of reality, requiring a slight re-adjustment on my part. Even after I had learned to expect it, I couldn’t escape the impression that a piece of another world – alien to me because of superior intellect and disability, but also for a quality of will that I have never experienced anywhere else – was moving in slow and inexorable progression through our space and time, from the little bridge to the office door, almost running over my toes.

  The mechanical voice would say, ‘Good morning’, or inquire, ‘How are you?’, or something like that … and Hawking’s working day would begin.

  PART IV

  2000–2011

  17

  ‘An expanding horizon of possibilities’

  IN A STATEMENT in january 2000, part of an interview for the millennium focusing on his predictions about what the future held in store for the human race, Hawking summed up his thoughts on the issue of genetic engineering. Humans, he said, have had no significant changes in their DNA over ten thousand years. But soon they will no longer have to wait for biological evolution to make changes for them – and they won’t wait. In the next thousand years we will probably be able to redesign our DNA completely, increasing our brain size. Whatever bans are placed on genetic engineering in humans, it will surely be allowed on animals and plants for economic reasons, ‘and someone is bound to try it on humans unless we have a totalitarian world order. Someone will improve humans somewhere. I am not advocating human genetic engineering. I am just saying it is likely to happen and we should consider how to deal with it.’1