Stephen Hawking

186 Twentieth-Century Science |Physics

Scientist of the Decade: Stephen Hawking (1942– ) On January 8, 1942, Stephen Hawking was born in a hospital in Oxford, England. His parents, Frank and Isobel Hawking chose to have their child delivered in Oxford rather than staying closer to their home in Highgate, a northern suburb of London, to escape the risk from German bombing. Despite the ongoing World War II, the German and British air forces had agreed not to bomb each other’s great university centers of Oxford and Cambridge, Heidelberg and Göttingen. Both those places and the date of Hawking’s birth were significant. He would attend college at Oxford and earn his doctorate at Cambridge, where he would later occupy a faculty position once held by Sir Isaac Newton, whose 300th birthday year had just begun. Perhaps an even more remarkable coincidence is that January 8 was the 300th anniversary of the death of the great Galileo Galilei. By turning his telescope to the skies, Galileo had transformed humanity’s view of other planets and of Earth’s place in the cosmos. In his career, Hawking would become one of the 20th-century physicists who transformed the scientific understanding of the cosmos itself. To his colleagues, Hawking’s insights and scientific publications are his most important contributions, but to the broader society, he is known and appreciated for his popular books and for his unquenchable optimism in the face of profound disability. Stephen came by his great intelligence and free spirit naturally. Both of his parents had graduated from Oxford but discovered each other at the medical institute where Frank was studying tropical medicine and Isobel was working as a secretary. They were viewed as somewhat eccentric in St. Albans, 20 miles farther north of London, where they moved when Stephen was eight. Isobel was an intellectual with a strong social conscience and an attraction to left-wing political causes, while Frank was frugal to a fault. He spent little on his personal appearance or on the family car, which was a former London taxi that he bought for £50. During Stephen’s secondary education (equivalent to junior high school in the United States) at the prestigious St. Albans school, he was a satisfactory but not outstanding student. He did better on exams than his coursework, since he preferred

Stephen Hawking, the celebrated physicist, whose book A Brief History of Time: From the Big Bang to Black Holes won him popular acclaim (AIP Emilio Segrè Visual Archives, Physics Today Collection)

building models and inventing complex games to homework. Looking ahead, he aimed to be a research scientist like his father. Stephen preferred mathematics and physics, but Frank persuaded him to substitute chemistry, which he saw as more practical, for math. When Stephen began to study general relativity, the lack of formal mathematics courses caused him some difficulty, but it allowed him to think more pictorially rather than in equations. That proved to be a great advantage for him when disease struck and writing mathematical expressions became increasingly difficult. Hawking entered Oxford in 1959 at age 17 at a time when a student’s brilliance was valued above hard work. The only required examinations were the finals, and like many of his classmates, he coasted through his courses. After three years, he

Chapter 1 | 1981–1990 187 was ready to graduate. Oxford offered four levels of degrees, and he was on the borderline between first- and second-class degrees. He told a panel of examiners that he intended to do research at Cambridge if he earned a first-class degree, and the examiners agreed to give it to him. As Hawking began to settle into his research at Cambridge, tragedy struck in the form of a medical diagnosis. He learned he had amyotrophic lateral sclerosis (ALS), a disease that attacks the muscles, eventually leading to paralysis and death. It is the same disease that killed the famous baseball star Lou Gehrig and has come to be named for Gehrig in the United States. The physician’s prognosis was that he had about two years to live. At first Hawking saw no reason to continue his Ph.D. project, since he would not have time to finish it. However, his inherent optimism eventually took hold. He realized that as long as he was alive and had an active mind, he had something to live for. He knew he would need help, but he was determined to make the most of whatever time he had left. No one helped him more than Jane Wilde, whom he had met at a party in 1963 soon after his ALS symptoms had started. Not even his dire prognosis could stand in the way of love, and he and Jane soon became engaged. His ALS symptoms progressed but at a much slower pace than expected, and he completed his Ph.D. in the summer of 1965. The couple married in July of that year. Hawking was offered a research fellowship in theoretical physics at Cambridge, which he accepted. Despite his increasing disability, he and Jane managed a remarkably normal life, which included children. At work, it did not take him long to capture the attention of fellow physicists. He elected to study black holes, which had been predicted in the 1930s (see chapter 4) but had never been observed. He wanted to reconcile the mathematical description of a black hole, which predicted a “singularity” of infinite density at its center, with a physical world in which infinities are not possible. In collaboration with Roger Penrose (1931– ) of Oxford University, whose mathematical skills complemented his physical insights, Hawking developed a theory that described the physics of black holes yet avoided the singularity.

In the early 1970s, astronomers discovered an X-ray emitting object in the constellation Cygnus, which they named Cygnus X-1. By 1974, Hawking and most astrophysicists expressed 80 percent confidence that the object was a black hole with a star in orbit around it. The X-rays were the result of emissions from the star’s gases as they were drawn into the black hole and heated to exceedingly high temperatures. Impishly, Hawking decided to provide himself some “insurance” if he were wrong. He made a bet with his good friend Kip Thorne (1940– ), an astrophysicist at Caltech, promising Thorne a one-year subscription to Penthouse magazine if Cygnus X-1 turned out to contain a black hole. If not, he would have the consolation of a four-year subscription to the British magazine Private Eye. In 1990, the confidence level that Cygnus X-1 was a black hole had risen to 95 percent, and Hawking paid off the bet. In 1982, faced with large expenses for his medical care and for his children’s school tuition, Hawking was looking for additional income. He had always enjoyed sharing his research with a wider audience than just his academic colleagues and students, and he was confident he could write a short book for general audiences about his unique perspectives on the universe. The book, A Brief History of Time: From the Big Bang to Black Holes, did not come as easily as he thought—it was not published until 1988, but its success exceeded even his own most optimistic expectations. Despite his medical condition, Hawking has always considered his life “normal,” even after an emergency tracheotomy cost him the remaining use of his voice in 1985. Normal people sometimes divorce, as Jane and Stephen Hawking did in 1990. He and one of his nurses, Elaine Mason, left their spouses to live together and eventually marry. Elaine’s husband, David, had designed the computer hardware for Hawking’s wheelchair. Today Stephen Hawking continues his research and writing. In 2002, Cambridge University celebrated his 60th birthday with a symposium entitled The Future of Theoretical Physics and Cosmology, published the lectures as a book, and broadcast them on BBC television. Hawking offered no bets as to how many more birthdays he would celebrate, but he clearly intends to outlive any predictions anyone cares to make.