Also see "Being Stephen Hawking," the profile of Stephen Hawking by former Nature editor John Maddox.
Two decades after rocketing to scientific stardom with his book A Brief History of Time, Stephen Hawking still knows how to make an entrance. On a mild March evening in Pasadena, California, 4,500 people fill the convention center to hear him give a talk called “Why We Should Go Into Space.” Shortly after 8 p.m. the lights dim, a few thousand conversations stop, and the soaring trumpet fanfare from Richard Strauss’s Also Sprach Zarathustra (better known as the theme from 2001: A Space Odyssey) fills the room. Hawking is in the house. The crowd turns to watch the frail physicist being wheeled at a good clip down the center aisle. He is wearing a charcoal gray suit and an open-neck white shirt; his head slumps toward his right shoulder; his hands are folded neatly in his lap. The music segues to The Blue Danube Waltz as he rolls up a ramp to the stage.
Hawking sits silently for a few moments, alone at center stage, before a member of his Cambridge, England, posse appears. Sam Blackburn, a graduate student who manages the beeping, bulky communications complex that is Hawking’s wheelchair, runs over and makes a few adjustments to his boss’s Lenovo ThinkPad X61 laptop. The iconic synthesized voice kicks in. “Can you hear me?” Hawking asks. The crowd cheers.
That cheer follows Hawking wherever he goes, in part because he shouldn’t even be here. In 1963, while a graduate student at the University of Cambridge, he was told he had amyotrophic lateral sclerosis, or Lou Gehrig’s disease, a diagnosis that usually proves fatal within five years. Yet he pressed on, becoming one of the world’s leading physicists and a best-selling author. He has plumbed the depths of black holes and sought to explain the beginning of time. He has been a guest on Star Trek: The Next Generation and has met the Dallas Cowboys cheerleaders. He has been married twice, has three children (“The disease only affects voluntary muscle,” he reportedly once commented), and is now a grandfather. Judith Croasdell, Hawking’s ruthlessly devoted personal assistant, says his schedule is fully booked through 2012. Oh, yes—and he’s also working on a new theory about the origin of the universe.
Hawking’s latest work has received mixed reviews. Some of his colleagues compare it unfavorably with the achievements that made his reputation. At the beginning of his career, in the late 1960s, Hawking proved that the universe must have started from a singularity, a point of infinite density. A few years later he found that black holes gradually shrink, fade, and die—a paradigm-shifting insight with thorny theoretical consequences that physicists are still pondering. His subsequent ideas have stirred controversy and skepticism, however, and Hawking’s influence on cosmology and physics is clearly not what it once was. In the popular realm, too, his star has dimmed. As the Pasadena event testifies, Hawking can still pack a room, but he has lost much of his iconic status. None of his books since Brief History have come close to its runaway success. The master of black holes is himself becoming steadily less visible.
Late last year reports circulated that Hawking would be retiring from Cambridge in 2009 and that he might even leave England to join the Perimeter Institute, an innovative research center just outside Toronto. Hawking, Croasdell assured me, will neither be retiring nor abandoning Cambridge, but this year will bring a significant transition. On September 30 he will relinquish his prestigious post as the Lucasian Professor of Mathematics at Cambridge, a position once occupied by Isaac Newton, which Hawking has held since 1979. He turned 67 on January 8, the maximum age for holding the Lucasian chair, and so will continue at the university with a new title, Emeritus Lucasian Professor.
No one should have believed the rumors. Retiring is no more of an option for Hawking than ceasing to think would be. What he is reaching for now is closer to the opposite: a defense and extension of the kind of sweeping cosmological ideas that first shot him to fame. In other words, a capstone to his career—or, to be blunt, a comeback.
It is challenging for any academic in his sixties to reclaim the aura of youthful genius, and especially so for a man whom the popular media routinely likened to Albert Einstein. And then there is Hawking’s most formidable antagonist: his own withered body. “I imagine it has become very difficult for him to work, and that’s been the major cause of his being out of the game, so to speak,” says Leonard Susskind, a theoretical physicist at Stanford University. “In the last number of years, he has been so incapacitated that it has been very difficult for him to keep up with what is happening in the field.”
Nevertheless, Hawking continues his almost ludicrously grand program. “My goal is simple,” he famously explained. “It is a complete understanding of the universe, why it is as it is, and why it exists at all.”
Into the Abyss
As an undergraduate at Oxford University, Stephen William Hawking was a wise guy, a provocateur. He was popular, a lively coxswain for the crew team. Physics came easy. He slept through lectures, seldom studied, and criticized his professors. That all changed when he started graduate school at Cambridge in 1962 and subsequently learned that he had only a few years to live.
The symptoms first appeared while Hawking was still at Oxford. He could not row a scull as easily as he once had; he took a few bad, clumsy falls. A college doctor told him not to drink so much beer. By 1963 his condition had gotten bad enough that his mother brought him to a hospital in London, where he received the devastating diagnosis: motor neuron disease, as ALS is called in the United Kingdom. The prognosis was grim and final: rapid wasting of nerves and muscles, near-total paralysis, and death from respiratory failure in three to five years.
Not surprisingly, Hawking grew depressed, seeking solace in the music of Wagner (contrary to some media reports, however, he says he did not go on a drinking binge). And yet he did not disengage from life. Later in 1963 he met Jane Wilde, a student of medieval poetry at the University of London. They fell in love and resolved to make the most of what they both assumed would be a tragically short relationship. In 1965 they married, and Hawking returned to physics with newfound energy.
Also that year, Hawking had an encounter that led to his first major contribution to his field. The occasion was a talk at Kings College in London given by Roger Penrose, an eminent mathematician then at Birkbeck College. Penrose had just proved something remarkable and, for physicists, disturbing: Black holes, the light-trapping chasms in space-time that form in the aftermath of the collapse of massive stars, must all contain singularities—points where space, time, and the very laws of physics fall apart.
Before Penrose’s work, many physicists had regarded singularities as mere curiosities, permitted by Einstein’s theory of general relativity but unlikely to exist. The standard assumption was that a singularity could form only if a perfectly spherical star collapsed with perfect symmetry, the kind of ideal conditions that never occur in the real world. Penrose proved otherwise. He found that any star massive enough to form a black hole upon its death must create a singularity. This realization meant that the laws of physics could not be used to describe everything in the universe; the singularity was a cosmic abyss.
At a subsequent lecture, Hawking grilled Penrose on his ideas. “He asked some awkward questions,” Penrose says. “He was very much on the ball. I had probably been a bit vague in one of my statements, and he was sharpening it up a bit. I was a little alarmed that he noticed something that I had glossed over, and that he was able to spot it so quickly.”
Hawking had just renewed his search for a subject for his Ph.D. thesis, a project he had abandoned after receiving the ALS diagnosis. His condition had stabilized somewhat, and his future no longer looked completely bleak. Now he had his subject: He wanted to apply Penrose’s approach to the cosmos at large.
Physicists have known since 1929 that the universe is expanding. Hawking reasoned that if the history of the universe could be run backward, so that the universe was shrinking instead of expanding, it would behave (mathematically at least) like a collapsing star, the same sort of phenomenon Penrose had analyzed. Hawking’s work was timely. In 1965, physicists working at Bell Labs in New Jersey discovered the cosmic microwave background radiation, the first direct evidence that the universe began with the Big Bang. But was the Big Bang a singularity, or was it a concentrated, hot ball of energy—awesome and mind-bending, but still describable by the laws of physics?