Inflation Gets Chaotic
In 1983, the same year that Hawking and Jim Hartle published their no-boundary proposal, Andrei Linde solved some of the still nagging problems of inflation theory with a new suggestion. The first person in the West to whom he mentioned ‘chaotic inflation’ was Hawking. Hawking was enthusiastic.
Both ‘old’ and ‘new’ inflation had assumed that inflation was just an intermediate short phase in the history of the early universe, that the universe was in a state of thermal equilibrium (meaning it was the same temperature everywhere) before inflation started, relatively homogeneous and large enough to survive until the inflation process got underway. Linde abandoned these assumptions in his chaotic inflation scenario, which didn’t require thermal equilibrium, and in which inflation could begin earlier, closer to the Big Bang.
The universe before the inflationary period could have been in a chaotic state. All that was needed was for minuscule parts of that chaos to be able to inflate, becoming smoother and more isotropicfn1 as they did so, like balloons that started out as crinkly pieces of rubber and ended up smooth balls. For all we know, only one tiny part of the chaos did that, though that is probably not likely. In any event, our balloon, as it inflated, pushed other inflating bits far out of range of our potential sight. Maybe other parts of the universe are still chaotic. Or maybe everything is smooth everywhere.
In chaotic inflation there is no phase transition or supercooling at all. Instead, there is a field that has large values in some regions of the universe, while not in others, a kind of ‘lucky negligence of the Creator’, as Linde puts it.13 The energy in the regions with large values, Linde was thinking, would be great enough to have a repulsive gravitational effect, causing them to expand in an inflationary way, while in the regions of the field where the values were too small this could not happen. Inflation in the regions where it did happen would create enormous homogeneous islands out of the original chaos, each one much larger than our observable universe. In these regions, the energy of the field would decrease slowly and, in some of them, eventually allow the expansion to reach the rate of expansion that we observe. Have a sufficient number of these regions around and we are highly likely to find one where the conditions were such as to produce a universe like the one we know, with the constants of nature that are arbitrary elements in our theories set just right to allow for the eventual existence of you and me. Maybe only one – in which case that one is ours.
A satisfying resolution to the story, but … not the end of it. Chaotic inflation theory also predicted a ‘second stage of inflation’, occurring much later – a speeding up of the expansion of the universe … perhaps in our own modern era. In the early eighties, that idea sounded like science fiction, even to Andrei Linde and Stephen Hawking. We will see that by the end of the century it would no longer be science fiction.
Meanwhile, the most remarkable aspect of inflation theory as it was beginning to be thought of in the early 1980s was that though theorists still had different ideas about the way inflation happened, there was agreement that the whole visible universe that we know today could have begun from a much smaller irregularity of mass and energy than anyone had imagined possible. As John Barrow phrased it in The Book of Universes: ‘Instead of eradicating [irregularities], inflation just swept them beyond the visible horizon in the universe today. They will still be there somewhere far away but the whole of our visible universe reflects the high isotropy and smoothness of a tiny patch of space that underwent inflation.’14
Our universe is not, of course, completely smooth. We have solar systems, galaxies and galaxy clusters. Even immediately following inflation, the bit that would eventually expand to be our visible universe must not have been as perfectly smooth as the imagined inflated balloon might suggest. It would be stretched out, but not so much as to avoid still having small variations that would have provided the seeds that could grow into all that astounding structure – large-scale modern variations in density indeed.
As early as the conference Hawking and Gibbons organized in Cambridge in the summer of 1982, the participants realized that inflation would have produced a particular pattern of variations.15 This would show up as a recognizable pattern of variation in the cosmic microwave background radiation. Observations at that time were not able to show any such pattern. Nevertheless, in the case for and against inflation, though no one could ever be an eye witness to the events with which our universe began, there was hope that there might someday be some evidence to show whether inflation theorists had it right.
fn1 Isotropy is the quality of being the same in all directions.
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‘It’s turtles all the way down’
LUCY WAS ELEVEN years old and completing her final year at Newnham Croft Primary School in the spring of 1982. She and her parents had decided that the best choice for the next stage of her education was the Perse School for Girls in Cambridge. Her brother Robert had been attending the Perse School for Boys since he was seven. In the 1960s a practical need for a job, so that he could get married, had sent Hawking off searching for singularities. This time, another practical need – for funds to pay Lucy’s school fees – launched him into a new enterprise that was to have a far-reaching impact on the Hawkings and others all over the world. It all began with Hawking’s decision to try to earn the money by writing a book about the universe – not an academic book but a book directed to people without a scientific education.
There had, of course, been other popular books about the universe and black holes. However, Hawking thought none of them spoke enough about the most interesting questions, the questions that had made him want to study cosmology and quantum theory: Where did the universe come from? How and why did it begin? Will it come to an end and, if so, how? Is there a complete theory of the universe and everything in it? Are we close to finding that theory? Is there a need for a Creator?
These were questions that he thought should interest everybody, not only scientists. However, science had become so technical and specialized that the general public was left out of the discussion. The trick in writing the book would be to make it understandable to non-scientists, and that meant using virtually no mathematics. He set to work dictating and completed the first draft in 1984.
Because it was a great deal of trouble dictating a book of this length, Hawking wanted the book to reach as many people as possible. His earlier books had been published by Cambridge University Press, one of the most prestigious academic publishers in the world, but after discussing his proposed new book with them and hearing them predict that it might sell 20,000 copies a year worldwide, Hawking decided he might do better with a publisher more attuned to the mass popular market. He wanted to see his book in airport bookstalls. His American agent discouraged this hope. Academics and students would buy the book, but the popular market, not likely. Hawking thought otherwise.
Several British publishers turned down the proposal, a decision they would regret.1 But there were some offers. One of the most surprising came from Bantam. Against the advice of his agent, Hawking chose them. Bantam might not have specialized in publishing science books, but they sold many, many books in airports. Bantam in the United States paid $250,000 for the American rights, and Bantam–Transworld in the UK offered £30,000 for the British. Paying that much for a science book was a gamble – one of the best gambles either publisher ever made.
A Year on the Brink
1985 was a difficult year for the Hawking family. That summer, the plan was for Hawking to spend a month in Geneva at CERN. He was looking forward, among other things, to exploring the implications of some recent calculations by Don Page and Raymond LaFlamme having to do with arrows of time. Hawking, his nurses, his secretary Laura Gentry, and some of his students left Cambridge and travelled directly to Switzerland while Jane, Jonathan, Lucy and Tim took a more circuitous and adventurous route, camping across Belgium and Germany. They were to meet Stephen at the Bayreuth Festival and scrub up fro
m campsite to formal standard to attend Wagner’s Ring cycle. At the time everyone was more concerned about Robert, who was trekking across Iceland and canoeing its northern coastline on a Venture Scout expedition, than they were about Stephen in safe, healthy Switzerland.2
On the eve of their arrival in Bayreuth, Jane found a public phone in Mannheim and rang her husband in Switzerland to arrange the schedule for the next day. A very distraught Laura Gentry answered the phone and urged her to come to Geneva at once. Stephen was in hospital with pneumonia. The situation looked grave. Jane arrived there to find Laura’s distress well warranted. He was on a life-support system, in an induced coma, barely hanging on to life.
Knowing Hawking’s physical future with ALS, but not aware of his fierce determination to live, doctors gave Jane the choice whether to have him disconnected from life support and allowed to die. This was a heartbreaking situation. The only way to save his life would be to perform a tracheotomy. Afterwards, there would be no more problems with coughing and choking, but he would never again be able to speak or make any vocal sound. That seemed a ghastly price to pay. Hawking’s speech was slow and difficult to understand, but it was still speech, and his only possible means of communication. Without it, he couldn’t continue his career or even converse. What would survival be worth to him? Nevertheless, Jane remembers that her decision was ‘clear and unequivocal, pronounced without a second thought, that Stephen must live, despite the prognosis of likely complications ahead’ given her by the doctors, for as his wife she saw herself ‘as the agent of life, not death’.3 ‘The future looked very, very bleak,’ she recalls. ‘We didn’t know how we were going to be able to survive – or if he was going to survive. It was my decision … but I have sometimes thought – what have I done? What sort of life have I let him in for?’4
When Hawking was strong enough, the University of Cambridge paid for an air ambulance to fly him back to Cambridge, where he was admitted to intensive care in Addenbrooke’s Hospital. Doctors made a final attempt to avoid the operation, but efforts to wean him off the respirator brought back the choking fits. A tracheotomy was the only way to proceed. Hawking remembers the vivid dreams he had during this time of flying in a hot-air balloon. He decided to take this as a symbol of hope.
Recovering slowly in the hospital, Hawking no longer breathed through his mouth and nose but through a small permanent opening made in his throat at about the height of his shirt collar. The only way he could communicate was to spell out words letter by letter by raising his eyebrows when someone pointed to the right letter on a spelling card.
After several weeks in intensive care, Hawking was allowed to come home on Sunday afternoons. Jane was determined that he would stay with her and their children and Jonathan rather than live in a nursing home. Since 1980, the community and private nurses arranged by Martin Rees had been coming for an hour or two each morning and evening to supplement the care given by Jane, the graduate assistant and Jonathan. However, from now on for as long as he lived, Hawking would need round-the-clock nurses. The cost was astronomical, far beyond the Hawkings’ resources. The National Health Service, which in Britain is paid for out of public funds, would have paid for a nursing home but could only offer a few hours’ nursing care in the Hawkings’ home plus help with bathing. ‘There was absolutely no way we could finance nursing at home,’ Jane says.5 Not only Hawking’s work as a physicist but any sort of meaningful life at all seemed at an end. It was an end they’d expected to come much sooner, but it was no less bitter for all that.
‘At times things have looked absolutely dire for us and then something has come out of those crises,’6 Jane has commented, recovering some of the optimism with which she had begun their marriage. Kip Thorne in California received word of his friend’s plight and immediately got in touch with Jane and suggested that she try to get funding from the John D. and Catherine T. MacArthur Foundation. Another friend, particle physicist Murray Gell-Mann, was on their board. The MacArthur Foundation agreed to help on a trial basis at first, with a grant to cover nursing care. More than three months after Hawking had entered the hospital, he came home to West Road in early November.
An unexpected ray of hope on the bleak horizon came when a computer expert in California, Walt Woltosz, sent a computer program he’d written for his disabled mother-in-law. ‘Equalizer’ allowed the user to select words from the computer screen and also had a built-in speech synthesizer. One of Hawking’s students devised an implement something like a computer mouse, so that Hawking could operate the program by a tiny movement that was still possible for him: squeezing this switch held in his hand. Should that fail him, head or eye movement could activate the switch.
Still too weak and ill to resume his research, Hawking practised with his computer. The first message he produced, after managing to make the computer say ‘Hello’ in the synthesized voice that was destined to become familiar all over the world, was to ask his graduate assistant, Brian Whitt, to help him finish writing his popular-level book.7 That would have to wait until he was more proficient with Equalizer, but before long he could produce ten words a minute, not very fast but good enough to convince him that he could continue his career. ‘It was a bit slow,’ he says, ‘but then I think slowly, so it suited me quite well.’ Later, his speed improved. He was for a time able to produce more than fifteen words a minute.
Here’s how the process worked, and still does, with a few modifications. The vocabulary programmed into the computer contains around 2,500 words, about two hundred of them specialized scientific terms. A screen full of words appears. The top half of the screen and the bottom half are highlighted alternately, back and forth, until Hawking sees the half-screen that includes the word he’s looking for highlighted, and squeezes the switch in his hand to choose that half-screen. Then lines of words on that half-screen are highlighted one after the other. When the line with the word he wants is highlighted, Hawking squeezes the switch again. The words on that line are then highlighted one by one. When the word he wants is highlighted, he presses the switch again. Sometimes he misses and the words or lines have to start over. There are a few often-used phrases, such as ‘Please turn the page’, ‘Please switch on the desk computer’, an alphabet for spelling out words not included in the program, and, I am told, a special file of insulting remarks, though I haven’t seen him use that.
Hawking selects the words one by one to make a sentence, which appears across the lower part of the screen. He can send the result to a speech synthesizer, which pronounces it out loud or over the telephone. (One strange fault with the process is that it cannot pronounce the word photon correctly, but always comes out with foe-t’n.) He can also save something on a disk and later print it out or rework it. He has a formatting program for writing papers, and he writes out his equations in words, which the program translates into symbols.
Hawking writes his lectures this way and saves them on disks. He can listen ahead of time to the speech synthesizer deliver a lecture, then edit and polish it. Before an audience he sends his lecture to the speech synthesizer a sentence at a time. An assistant shows slides, writes Hawking’s equations on the board, and answers some of the questions.
Hawking’s synthesized computer voice varies the intonation and doesn’t sound like a monotonal robot, which to him is an extremely important feature. At first he wished it gave him a British accent, but after a while he became so identified with it that ‘I would not want to change even if I were offered a British sounding voice. I would feel I had become a different person.’8 Just what accent it does give him is uncertain. Some people say it’s American or Scandinavian. To me it sounds East Indian, perhaps because of its slightly musical inflection. Hawking can’t inject emotion into the voice. The effect is measured, thoughtful, detached. Hawking’s son Tim thinks his father’s voice suits him. Tim of all the children is least able to remember what Hawking’s own voice sounded like. When he was born in 1979, there was little of that left.
Doe
s all of this make conversation with Hawking seem like talking to a machine – like something alien, from science fiction? At first just a little. Soon you forget all about it. Hawking is comfortable with the odd situation and patient when others are not. When he was reading parts of this book while I held the pages, it was his nurse, not he, who suggested that it was unnecessary for me to wait for Hawking to select ‘Please turn the page’, which involved a number of manoeuvres on the computer screen. As soon as he started clicking, she said, I could turn the page and save him trouble and time. He’d put up with my way of doing things for an hour and a half without indicating that I was in any way inconveniencing him. As it happened, the next time Hawking ‘clicked’ and I turned the page, he was making a comment, not asking for a page turn.
Hawking’s sense of humour is contagious and likely to break out at any moment. However, when one interviewer commented to Hawking that it must be frustrating, telling jokes and having your listeners anticipate the punchline before you have a chance to crack it, Hawking admitted that ‘I often find that by the time I have written something, the conversation has moved on to another subject.’9 Nevertheless, when his face lights up with a smile, it is difficult to believe this man has many problems. The Hawking grin is famous, and it reveals the quality of his love for his subject. It’s a grin that says, ‘This is all very impressive and serious, but – ain’t it fun!’
It is, of course, nothing short of miraculous that Hawking has been able to achieve everything he has, even that he’s still alive. However, when you meet him and experience his intelligence and humour, you begin to take his unusual mode of communication and his obviously catastrophic physical problems no more seriously than he seems to himself. That is the way he wants it. He chooses to ignore the difficulty, ‘not think about my condition, or regret the things it prevents me from doing, which are not that many.’10 He expects others to adopt the same attitude.
Stephen Hawking, His Life and Work Page 18