By this time Robert Hawking was a university student, studying physics and rowing for his Cambridge college, Corpus Christi. One of the television specials showed him racing on the river while the rest of the family, including Hawking with his synthetic voice, cheered from the bank. Lucy was considering a career in the theatre. She appeared in the Cambridge Youth Theatre’s award-winning production of The Heart of a Dog, a Soviet political satire from the 1920s. The production went on to run in Edinburgh and London as well. When the London run conflicted with her entrance examinations for Oxford, Lucy made the daring decision to miss them and allow her application to be judged only on her interview and her A-level exam results. She was admitted to Oxford. As for ten-year-old Tim, Hawking said, ‘Of all my children, he is probably the one most like me.’2 He and Tim enjoyed playing games. Hawking usually won at chess, Tim at Monopoly. ‘So we’re both quite good at something,’ proclaimed Tim.3 In 1988 the American photographer Stephen Shames had taken pictures of them engaged in an impromptu game of hide-and-seek. Tim excelled at that. He could tell when his father was getting near by the hum of the wheelchair motor.
Lucy told ABC’s 20/20 that she and her father ‘get on quite well’, though both are stubborn. ‘I’ve had lots of arguments with him actually, I must admit, with neither of us willing to give ground. I think a lot of people don’t realize just how stubborn he is. Once he gets an idea in his head, he will follow it through no matter what the consequences are. He doesn’t let a thing drop … He will do what he wants to do at any cost to anybody else.’4 This sounds harsh, but when I spoke with Lucy, it was very clear she’s enormously fond of her father and respects his opinions. In the ABC interview, she said that she thinks he has to be stubborn in his situation. It’s a necessary mode of survival for him. His strength of will keeps him working day in, day out, grinning and delivering funny one-liners and ignoring a grim physical situation. If it also occasionally makes him appear spoiled and self-centred, it seems entirely reasonable to forgive him. About his health and the fear of his dying, Lucy said, ‘I always think, “Oh he’s going to be all right”, because he’s always pulled through everything that’s happened to him. You can’t help worrying about someone who’s so frail. I get quite worried when he goes away.’5 Lucy had learned to cope with such fears early. Her mother had tried to explain to her what ALS was when Lucy was a child. Then, Lucy had cried, certain that ‘he was going to die the next day’.6
In the academic world physicists continued to express tremendous respect for Hawking but were a little nonplussed by all the media hype. It didn’t take higher maths to multiply book sales figures in the millions and find they amounted to more than Lucy’s school fees. There was an occasional hint of sour grapes, a half-suppressed mutter of ‘His work’s no different from a lot of other physicists’; it’s just that his condition makes him interesting.’ One colleague commented that ‘in a list of the twelve best theoretical physicists this century [the twentieth], Steve would be nowhere near’.7 That was arguably true, considering the astounding list of physicists who lived in the twentieth century, and Hawking would have agreed, though the ‘nowhere near’ was perhaps a bit harsh. But there was surprisingly little disparagement. He could more than hold his own in any contemporary company, and everybody knew it. Moreover, his colleagues enjoyed him. Sidney Coleman of Harvard, who rivalled Hawking not only as a physicist but also as a classroom comedian, was pleased that Hawking’s celebrity brought him more and more often to America, and frequently to New England. Other physicists who were sometimes unfairly eclipsed by Hawking did not blame him personally.
Nevertheless, it wasn’t unreasonable to suggest that Hawking’s scientific accomplishments alone would never have made him the celebrity he was or sold millions of books. Were those correct who said he’d exploited his pathetic condition and ridden his wheelchair to fame and fortune? The truth is, although Hawking would almost certainly prefer it otherwise, most of the non-physics world probably appreciates him more for his spirit than for his scientific achievements. He’s not the only person who’s overcome staggering odds and maintained a positive attitude in adverse circumstances, but who else has done it with quite such brilliant success and engaging style?
For over a quarter of a century Stephen Hawking, perhaps with lapses we’ll never know about, had kept up this spirit of optimism and determination for his own benefit. His survival and success depended on his doing so. However, it was a responsibility only to himself and to his family. In the late 1980s, it became a responsibility to millions all over the world for whom he was an inspiration. Many, not only the disabled, expected him and his wife to go on proving that in spite of tragedy, life and people could still be absolutely splendid. We shouldn’t be surprised if Hawking was leery about having that larger responsibility thrust on him. He was, he said, no more than simply human. Hawking would later comment that he did not see himself as being tragic and romantic, something like ‘a perfect soul living in a flawed body. I am proud of my intelligence, but I have had to accept that the disability is also a part of me.’ And for disabled people Hawking had become a superb role model. Nevertheless, the disparity between what he’d achieved and what most could expect was sometimes discouraging. In most things except his illness Hawking has been outrageously lucky.
Jane Hawking pointed out that if her husband were an obscure physics teacher, she couldn’t have convinced a foundation to donate over fifty thousand pounds a year for nurses. There would be no computer program. He would be sitting day after pointless day in a nursing facility, away from his home and family, mute, isolated and wasted. Her bitterness about the way the National Health Service failed them led her to campaign for those with similar problems, trying to get the NHS to provide money for home nursing rather than tear apart families. The Hawking image encouraged universities to set up dormitories equipped for students needing round-the-clock nurses in order to attend classes. An abstract glass mini-sculpture sits on a filing cabinet in Hawking’s office, a gift from ‘Hawking House’, a dormitory at the University of Bristol. Cambridge built a similar facility.
Whatever the effect on the rest of the world, in 1989 Stephen Hawking had ‘made it’, against stupendous odds. The Queen named him a Companion of Honour, making him a member of an Order that consists of the Queen herself and not more than sixty-five other members. It is one of the highest honours she can bestow. The University of Cambridge did what it rarely does and gave one of its own faculty an honorary doctorate. Hawking received his degree from Prince Philip, chancellor of the university, and joined in the pageantry, going to and from the Senate House to the accompaniment of the choirs of King’s College and St John’s College and the Cambridge University Brass Ensemble. ‘This year has been the crowning glory of all Stephen’s achievements,’ Jane Hawking said. ‘I think he is very happy about it.’8 He loved doing the work he did. ‘I have a beautiful family, I am successful in my work, and I have written a bestseller. One really can’t ask for more,’ he said.9 He’d earned this fame, and he was enjoying it. For someone who’d thought at the age of twenty-one that he had no reason to go on living, it was heady stuff indeed, a delicious joke on fate.
But fate had its jokes too. There was an obvious down side to the overwhelming success of his book. Less time for his scientific work. Too many ‘extracurricular activities’, his students lamented. Too many visitors, but he seldom turned them away. Too many invitations, but he seemed incapable of refusing them. Too much travelling, but he scheduled more and more of it. Too much mail. He had answered the first few letters about A Brief History of Time personally, but that had almost immediately become impossible. His graduate assistant and his secretary took on major responsibility for answering his mail.
Notoriety was not all fun. ‘It obviously helps me to get things done and it enables me to help other disabled people,’ Hawking told a journalist. ‘It also means I can’t go anywhere incognito in the world. Wherever I go, people recognize me and come up to say how t
hey enjoyed the book and can they have a photograph with me. It is gratifying that they are so enthusiastic, but there are times that I would like to be private.’10 He came up with a solution, programming his voice synthesizer to say, ‘People often mistake me for that man.’ Or, ‘I am often mistaken for Stephen Hawking.’ No one was fooled.
As Hawking juggled his increasingly unmanageable schedule, colleagues began to worry that he would neglect his science. However, Hawking’s scientific work did continue. He tied up one small loose end when he was once again visiting Caltech in June 1990. The evidence having to do with Cygnus X-1 that had emerged during the sixteen years since he and Thorne had made their bet gave a 95 per cent certainty that Cygnus X-1 is a black hole. It was time, Hawking decided, to settle with Thorne. When Thorne was away in Moscow, Hawking, with help from ‘accessories to the crime’, broke into his office where the framed bet was lodged and wrote a note on it conceding the bet. Stephen signed the note with his thumbprint.
While Hawking travelled the globe as a celebrity in the late 1980s, in his head he travelled distances that make these journeys seem paltry by comparison. John Wheeler had earlier (in 1956) introduced the idea of ‘quantum wormholes’. Hawking was now attempting adventures through these wormholes into even more exotic climes, into ‘baby universes’. Let’s stand with him outside space and time, to get a better view.
A New Look at the Cosmic Balloon
Hawking asks us to imagine an enormous balloon, inflating rapidly. The balloon is our universe. Dots on the surface are stars and galaxies. The dots cause dimples and puckers in the surface. As Einstein predicted, the presence of matter and/or energy causes a warping of spacetime.
When we look at the cosmic balloon through a not-very-powerful microscope, the surface, regardless of the puckers, looks relatively smooth. Looking through a much more powerful microscope, we find it isn’t smooth after all. The surface seems to be vibrating furiously, creating a blur, a fuzziness (see Figure 10.9).
We’ve seen such fuzziness before. The uncertainty principle causes the universe to be a very fuzzy affair at the quantum level. It’s never possible to know precisely both the position and the momentum of a particle at the same time. One way to picture this quantum uncertainty is by imagining that each particle jitters in a sort of random microscopic vibration. The closer we try to look, the more violently it jitters. Scrutinize the quantum level with the greatest possible care, and we at best are able to say only that a particle has this probability of being here – or that probability of moving like that. The surface of the cosmic balloon is unpredictable in a similar way. Under high enough magnification the quantum fluctuation becomes so incredibly chaotic that we can say there’s a probability for it to be doing – anything.
What did Stephen Hawking think this ‘anything’ might be? In the late 1980s he was pondering the probability that the cosmic balloon will develop a little bulge in it. More familiar balloons, the ones at parties, do that if one point on the surface is weak. Usually party balloons burst immediately when that happens, but on rare occasions a miniature balloon bulges out of the surface. If you could see this happening to our cosmic balloon, you would be witnessing the birth of a ‘baby universe’.
It sounds spectacular: the birth of a universe. Will we ever witness such an event? No, first because it happens in imaginary time, discussed in Chapter 10, not ‘real’ time. Another reason we won’t see it, said Hawking, is that if anything can truly be said to start small, it’s a universe. The most probable size for the connection between our universe and the new baby – the umbilical cord, if you will – is only about 10-33 centimetres across. To write that fraction you use 1 as the numerator and 1 followed by thirty-three zeros for the denominator. That’s small! The opening – the wormhole, as it’s called – is like a tiny black hole, flickering into existence and then vanishing after an interval too short to imagine. We’ve spoken of something else with an extremely short life span: in Chapter 6, when we discussed Hawking radiation, we saw that you can think of fluctuations in an energy field as pairs of very short-lived particles. Wormholes similarly are a way of thinking about fluctuations in the fabric of spacetime: the surface of the cosmic balloon.
Figure 12.1. Wormholes and baby universes
Hawking’s suggestion was that the baby universe attached to this umbilical cord may not be short-lived, and small beginnings don’t always continue small. He was thinking that eventually the new universe might expand to become something like our present universe, extending billions of light-years. Like our universe, but empty? Not at all. ‘Matter,’ Hawking pointed out, ‘can be created in any size universe out of gravitational energy.’11 The result might later be galaxies, stars, planets and, perhaps, life.
Are there many baby and grown-up universes? Do they branch off everywhere? Right inside the kitchen sink? Inside your body? Hawking said yes, it may be that new universes are constantly coming into existence all around us, even from points inside us, completely undetectable to our senses.
Perhaps you’re wondering whether our universe began as a bulge from the side of another. It’s possible, declared Hawking. Our universe may be part of an infinite labyrinth of universes, branching off and joining one another like a never-ending honeycomb, involving not only a lot of baby universes but adult universes as well. Two universes could develop wormhole connections in more than one spot. Wormholes might link parts of our own universe with other parts of it, or with other times (Figure 12.1).
Life in the Quantum Sieve
Let’s stretch our imaginations and look at all of this from the point of view of an electron. If there are quadrillions of wormholes flickering in and out of existence at every point in the universe, an electron is facing something like an enormous, furiously boiling pot of thick porridge. Moving across it is about as tricky as travelling across a giant, continuously changing sieve. An electron trying to move in a straight line in such an environment is almost certain to encounter a wormhole, fall in, and go shooting off into another universe. That sounds suspiciously as though matter will be disappearing from our universe, which isn’t allowed. However, according to this theory, there is no danger of such a loss. An identical electron comes back the other way and pops into our universe.
Wouldn’t we notice this substitution of electrons? We won’t see it that way. To us this event will look like one electron moving in a straight line. Hawking was thinking that the presence of wormholes, however, will make all electrons move as though they have a higher mass than they would if there were no wormholes. Therefore, if we’re to try to predict particle masses with any theory, it’s important to know whether or not there really are such things as wormholes.
The theory said that if an electron falls into a wormhole accompanied by a photon, it won’t appear to be anything out of the ordinary. We will observe only the normal exchange of a messenger particle in an electromagnetic interaction, in which one electron emits a photon and another absorbs it. Hawking was suggesting that perhaps all particle masses and all particle interactions – the ceaseless activity of the four forces, all over the universe – can be explained as this going into and out of wormholes.
You would be right to wonder, at this point, how particles could possibly pass through wormholes. Wormholes would be much smaller than even the smallest particles we know. As with Hawking radiation, what is impossible in any way we try to picture it is possible in quantum mechanics.
When Hawking calculated the effect of wormholes on the masses of particles such as electrons, his calculations at first suggested that the masses would be much larger than we actually observe for these particles. He and other researchers later managed to come up with more reasonable numbers. However, at the end of the 1980s Hawking was expressing doubts whether wormhole theory can predict the masses of particles for our universe or any other. As we saw in Chapter 2, when something must be measured directly and cannot be predicted by the theory, that’s called an arbitrary element. The masses of particles
and the strengths of the forces are, in every theory anyone has come up with so far, just such arbitrary elements. Wormhole theory may not make them any less arbitrary, but it might explain how they happen to be arbitrary. Hawking was thinking that the masses of particles and other fundamental numbers in nature may turn out to be ‘quantum variables’. That means they may be uncertain, like the paths of particles or what happens on the surface of the cosmic balloon. These numbers would be fixed at random at the moment of creation in each universe. A throw of the dice, so to speak, and then that’s settled for that particular universe – but no way to know from a theory how the dice will fall, or perhaps even to say that one way is definitely more probable than another. Hawking was not sure this was the case in wormhole theory. However, the idea that fundamental numbers in nature – maybe even the ‘laws of nature’ – might not be fundamental to the totality of universes, but different for different universes, was something that he would return to in another context later.
A Severely Warped Universe
‘It is a great mystery why quantum fluctuations do not warp spacetime into a tiny ball,’ says Hawking.12 Recall that this is one of the enigmas that theorists must solve in the quest for the Theory of Everything.
Physicists refer to this problem of the energy in the (so-called) vacuum as the cosmological constant problem. You’ll remember that Einstein theorized about something called the cosmological constant, which would balance gravity and prevent the universe from changing in size. He later called it ‘the greatest blunder of my life’. The term has come to have a related but slightly different meaning. The cosmological constant, as scientists now use the term, is a number which tells us how densely this energy in the vacuum is packed: the energy density of the vacuum. Common sense says there shouldn’t be any energy there at all, but, as we’ve seen, the uncertainty principle shows that ‘empty’ space isn’t empty. It seethes with energy. The cosmological constant (the energy density of the vacuum) ought to be enormous, and general relativity theory tells us this mass/energy should be curling up the universe.
Stephen Hawking, His Life and Work Page 20