Stephen Hawking, His Life and Work Read online

  Morris himself was more than pleased with the final result. He called Hawking ‘a symbol to millions of triumph over adversity and man’s insignificance in the face of an implacable cosmos out there’ and was satisfied that the film successfully conveyed that image. Compared with all previous work he had done, it was, Morris said, ‘less cerebral and more moving’, in spite of what might have seemed a difficult, esoteric subject, and even though in this film ‘everyone is smarter than me’.21

  In spite of the undeniable beauty of the film and its critical success, it never reached a mass audience. In fact, it was never marketed or released to theatres in a way that would have allowed it to do that. We shall never know what the result would have been if Hawking had won the argument rather than Spielberg.

  The world might have turned upside down when it came to Hawking’s personal life: Elaine had become hugely important to him; he had become a film star; but, with all that, when I visited him again a couple of years later in the office and common room in Silver Street, it was as though time there had stood still. The description I’d written in 1990 could have been written that day … the small clicking sounds, the words flitting back and forth, up and down, on the computer screen. The synthetic voice enunciated them politely. Students, nurses and colleagues passed in and out. At 4 p.m. the cups were lined up as precisely as a toy army on the counter in the common room. Former Lucasian Professors of Mathematics gazed down from their portraits on the intent little ‘rock group on a bad day’ as they sipped tea and talked their strange mathematical language. The figure in their midst was pitiful by all normal standards, like a guy on its way to the bonfire on Guy Fawkes Night. He wore a bib, and a nurse held his forehead and tipped his head forward so that he could drink his tea out of the cup she held under his chin. His hair was tousled, his mouth was slack, and his eyes were weary over the glasses that had slipped down his nose a little. But at a disrespectful quip from one of the students his face broke into a grin that would light the universe.

  My book in 1990 had ended with the words, ‘Whatever the future brings, in this unlikely, paradoxical story, we can hope it will be that grin an artist will capture someday in Hawking’s portrait, the portrait that will hang in the empty space still remaining on the common room wall beside his office door. Meanwhile the little plaque is a liar. The boss is not asleep.’

  That was more than twenty years ago. Hawking was forty-eight years old.

  14

  ‘Between film roles I enjoy solving physics problems’

  ANDREI LINDE, WORKING with alex vilenkin in the late 1980s and early 1990s, discovered that an inflationary universe has an amazing potential: in chaotic inflation theory, it can ‘self-reproduce’. The result is an enormous fractal arrangement of universes sprouting one out of another. Hawking’s ‘baby universe’ idea also proposed a multitude of other universes. Our own huge universe was suddenly looking small compared with a possible ‘multiverse’.

  Inflation Goes ‘Eternal’

  Imagine again one of those regions in the early universe that is inflating rapidly, while some of its neighbouring regions are not. Within that inflating region, Linde and Vilenkin thought, there would be sub-regions that would expand more rapidly than their parent region, while other sub-regions would not. Nor is that the end of the story. Sub-regions would beget sub-sub-regions, and so on and so forth. In other words each microscopic region that inflated would in turn be made up of microscopic sub-regions, some of which would inflate and be in turn made up of microscopic sub-sub-regions, and so on and so forth – an eternal inflationary universe scheme. ‘Eternal inflation’ would be a never-ending process of self-reproduction of the universe. As Linde described it, ‘the universe is a huge, growing fractal. It consists of many inflating balls that produce new balls, which in turn produce more balls, ad infinitum.’1 The universe we know and can observe is just one of these regions, or sub-regions, or sub-sub-regions. Cartoons portrayed Linde as a carnival balloon seller.

  Are there ‘parallel universes’ like ours? Not necessarily, though other universes something like ours can’t be ruled out. Even though the total picture including what is beyond ‘our universe’ may be irregular and hugely complicated, in our universe the situation is smooth and relatively simple. Inflation in other regions or sub-regions might also have produced large smooth universes. The whole thing may, in fact, become divided into infinitely many exponentially large regions. However, when energy levels in those other large regions decrease to levels similar to those in our universe today, they will each have different laws of physics. Eternal inflation will produce an infinite variety of universes. In John Barrow’s words, ‘we find ourselves faced with the likelihood that … we inhabit a single, simple patch of space and time in an elaborate cosmic quilt … of huge diversity and historical complexity, most of which is totally inaccessible to us.’2 And we don’t find our patch as it is because it is the most likely kind of universe. It is not.

  Barrow used the words ‘historical complexity’ advisedly, for if the whole picture is as eternal inflation describes, there is no reason to think that our own universe exists at or near the beginning of the eternal process. It might have originated as a sub-region of a sub-region of a sub-region – who knows how far we are down the line? In this model, our own universe has a beginning, but the big picture, the enormous fractal arrangement, perhaps need not have either a beginning or an end. Not everyone agrees that this picture stretches infinitely far into the past. Alan Guth, the founding father of inflation theory, working with Alex Vilenkin and Arvind Borde, thinks that the huge ‘eternal’ inflation scenario must have a past boundary, a beginning.

  If all this is taking place, shouldn’t we be able to notice it? The answer is no. The inflation happens so rapidly that the regions and sub-regions and sub-sub-regions, etc., become immediately independent of one another. They move apart faster than the speed of light, becoming separate pocket universes.

  In Linde’s words, ‘According to this scenario, we find ourselves inside a four-dimensional domain with our kind of physical laws, not because domains with different dimensionality and with alternate properties are impossible or improbable, but simply because our kind of life cannot exist in other domains.’3 Among an infinite variety of universes, it is likely – perhaps inevitable – that one of them, at least, will be the kind where our sort of life can exist. The anthropic principle is alive and well, and not at all the cop-out it once seemed.

  If we can’t see eternal inflation happening on our doorstep or anywhere else, is there any observational evidence – or even potentially possible evidence – for eternal inflation? Hawking was going to show that this is not a hopelessly far-out question, though it might have seemed so when eternal inflation first appeared on the scene.

  Global celebrity

  As the last decade of the twentieth century got underway, Hawking kept up the exhausting level of international travel that had begun soon after the surgery that cost him his voice. Plane flights and hectic schedules were possible for him as long as he had indefatigable, intrepid nurses with him. Travel included more than giving lectures, taking part in conferences and being escorted by dignitaries around tourist sites.

  Trips to Japan, in particular, where Hawking went no fewer than seven times in the 1990s, seemed to produce unusual adventures. Joan Godwin, who was with him as a nurse on most of these eastern jaunts, recalls that on one visit Hawking expressed a strong desire to see the northern part of the country. His hosts warned him that this was an area where earthquakes were expected. They suggested a safer destination. Sendai. Sendai is, of course, where the devastating earthquake and tsunami and the subsequent deadly problems with nuclear reactors occurred in 2011, but Joan recalls that they had a delightful visit there. Once the subject of earthquakes had come up, however, Joan did confer with Hawking about what she should do if one occurred. ‘Save yourself,’ he said. ‘Don’t worry about me.’

  During another visit to Japan, an inci
dent occurred that, though it represented no danger to Hawking physically, was perhaps a threat to his ego. On the bullet train platform he was surrounded as he often was by cameras and reporters clamouring for statements and pictures. Then, in the blink of an eye, they inexplicably turned their backs and sprinted off. Hawking was alone. Investigation revealed that a famous Sumo wrestler had alighted from a train on a nearby platform. Hawking was not the most important celebrity in the universe.

  Japan was also the setting for a story told by string theorist David Gross at Hawking’s sixtieth-birthday party conference in 2002:

  When you travel with Stephen you get to meet all sorts of people you would never meet otherwise. We didn’t get to meet the Emperor, which I regret, but we did get to meet somebody who I gather in Japan is even more popular and more famous, that is, the Green Tea Master, and we got to meet geisha girls, etc. But the most interesting experience was when Stephen insisted we all go to a karaoke bar. He actually got us to get up there and sing ‘Yellow Submarine’, which, if I were to try to reproduce, you would run screeching from the room. Every time the chorus came up Stephen would pipe in ‘Yellow Submarine’; he probably still has a ‘Yellow Submarine’ button that he can push!4

  Staying close to home was much less interesting. It was also no guarantee of safety. On 6 March 1991, the news spread quickly in Cambridge that Stephen Hawking had been knocked over by a taxi the evening before, crossing Grange Road, where he and Elaine were living in Pinehurst. It had been dark and raining, but the wheelchair had front and rear bicycle lights and should not have been difficult to see. His nurse screamed ‘Look out!’, and the speeding car caught his wheelchair from behind as he was crossing. He was thrown out on to the road, landing with his legs over what remained of the destroyed chair. It would have been a serious accident even for someone in a state of perfect health and fitness. Nevertheless, he was out of hospital back in his office two days later, with a broken arm in a sling and stitched-up cuts on his head. His personal assistant Sue Masey, his graduate assistant, students and friends had spent those two days frantically bringing in a new wheelchair from another part of the country and finding the necessary parts to repair his computer system, making sure his equipment was restored to normal as rapidly as Hawking.

  In 1992, Stephen and Elaine built a large modern house not far from the centre of Cambridge. From there, Hawking took a new route to his office, through an attractive old passage known as Maltings Lane, emerging to skirt a pond and cross a low-lying, wild, green area of grass and trees and small bridges known as Sheep’s Green. Then he crossed the River Cam where a weir separates the upper river from the part that runs through the Backs, and from there it was a straight shoot into Mill Lane and to his ramp at the DAMTP back entrance.

  Anyone familiar with that footpath through Sheep’s Green might expect that the narrow bridges would have presented a problem. They are barely wide enough to allow bicycles to cross, if cyclists are sufficiently skilful to avoid scraping their hands on the wooden railings built at handle-bar height. Hawking in his wheelchair ‘threaded the needle’ at speed, even in the dark. On one evening, making the trip home late with him, Joan Godwin stumbled off the ragged edge of the path and fell. Hawking, unaware she wasn’t still behind him, blazed merrily ahead. When a kindly gentleman helped Joan up, announcing that he was an orthopaedic surgeon and hoped she wouldn’t require his services, she asked him please to ‘stop that wheelchair’.

  The Inflation of Wrinkles

  In April 1992, George Smoot, an astrophysicist at Lawrence Berkeley Laboratory and the University of California at Berkeley, and his colleagues at several other institutions, announced that data coming in from the Cosmic Background Explorer (COBE) satellite had revealed ‘ripples’ in the CMBR. This was a hugely significant discovery. Those ripples were the first evidence of the elusive variations that astrophysicists and cosmologists had been looking for in vain since the 1960s. These tiny differences in the topography of the universe when it was only an estimated 300,000 years old were evidence of a situation that would have given gravity a fingerhold and allowed matter to attract matter into larger and larger clumps, eventually forming planets, stars, galaxies and clusters of galaxies. The no-boundary proposal stood to gain credibility from Smoot’s discovery. It had predicted both the overall smoothness of the universe and the deviations from that smoothness that COBE had found.

  Hawking recognized that the COBE findings might even be indirect observational evidence of Hawking radiation. As we have seen, according to inflation theory, long before the era in which the cosmic microwave background radiation originated – in fact, when the universe was far less than one second old – it went through a period of runaway inflation. Hawking pointed out that during that period the universe would have expanded so enormously and so rapidly that light travelling towards us from some faraway objects would never be able to reach us. It would have to travel at greater than the speed of light to do so. Hearing of some light being able to reach us, while other light can never reach us, suggests the event horizon of a black hole. Hawking proposed that there may indeed have been an event horizon in the early universe that was similar to the event horizon of a black hole, separating the region from which light reaches us from the region from which it doesn’t. From that ancient horizon, there would be radiation just as there is from a black hole, and thermal radiation like this has a characteristic pattern of density fluctuations. In the case of the early universe event horizon, these density fluctuations would have expanded with the universe, but then become ‘frozen in’. We would observe them today as a pattern of minuscule variations in temperature – the ‘ripples’ that Smoot found in the cosmic microwave background radiation. Those ‘ripples’ did indeed turn out to have the characteristic pattern of density fluctuations from thermal radiation such as Hawking radiation.

  Star of Stage and Screen

  In the autumn of 1992, opera-lover Stephen Hawking found himself portrayed on the stage of the Metropolitan Opera in New York City, or rather as a figure suspended somewhat above it. The opera was not Wagner. It was The Voyage, a new work by Philip Glass, who had composed the score for the film A Brief History of Time. The Met commissioned The Voyage to celebrate the 500th anniversary of Columbus’s journey to the new world, but Glass chose not to retell the story of Columbus. Instead he let Columbus symbolize the human longing to explore and discover.5 In the opera’s prologue, a wheelchair-bound figure, clearly meant to suggest Stephen Hawking, floated above the stage, intoning, ‘The voyage lies where the vision lies.’ A sky full of planets appeared as though he had conjured it, and he flew away.

  The following year, Hawking was more personally involved in one short escapade that remains a favourite memory not only for him but for many of the rest of us, travelling – in imagination – far more boldly into space than the real-life sub-orbital flight he still hopes to take. He was not, for a change, conveyed on the wings of theoretical physics.

  It began in the spring of 1993, at a party celebrating the release of the home video version of the film A Brief History of Time.6 Leonard Nimoy, who played the Vulcan Spock on Star Trek, was among the guests and had the honour of introducing Hawking. As People Magazine described it, ‘Vulcan’s most famous son and Earth’s most celebrated cosmologist instantly melded minds’7 – an allusion that any faithful Star Trek viewer would appreciate. When Nimoy learned that Hawking was an avid fan of Star Trek and, like nearly every other fan, longed to be on the show, he contacted the executive producer Nick Berman. Berman lost no time arranging for a three-minute scene to be added at the beginning of one of the regular weekly episodes, titled ‘Descent’.

  The scene was the ‘holodeck’ of the Starship Enterprise – a part of the ship that uses holographic technology to turn the fantasies of crew members into ‘reality’. This was the android Data’s fantasy – a poker game with Einstein, Newton and Hawking. Not surprisingly, Hawking was the only one who played himself. He was sent the script well ah
ead of time and programmed his lines into his voice synthesizer. In the 1990s and for most of the first decade of the twenty-first century, Hawking was still capable of a number of facial expressions, and these he put to good use playing his role. ‘Everyone was astonished at how much mobility his face has. The vitality behind it is very evident,’ commented the episode director Alex Singer; and John Neville, who played Isaac Newton, added, ‘When you get that smile in response to something you’ve said, it’s worth the whole day’s pay, really.’8 Brent Spiner, who as Data was the host of this remarkable poker game, summed it up: ‘When Rick Berman and I are in the old folks’ home sitting in rocking chairs, we’re going to be talking about the Hawk.’9 Hawking also seemed to be getting his priorities right: ‘Between film roles,’ he commented on the set, ‘I enjoy solving physics problems.’10 His one regret was that ‘unfortunately there was a red alert, so I never collected my winnings’ although he had ‘beaten them all’.11

  The cameo role on Star Trek brought Hawking back into the public limelight to a degree that almost exceeded the fame won him by A Brief History of Time and was an asset in publicizing his Black Holes and Baby Universes and Other Essays, which came out the same year, 1993. There soon were other appearances in pop culture. The song ‘Keep Talking’ on Pink Floyd’s The Division Bell album featured his computerized voice.

  Advocate and role model