Biography
Article abstract: Many consider Hawking to be the greatest physicist of the late twentieth century. His work combines the two primary developments of early twentieth century physics—general relativity and quantum mechanics—to explain the origins and structure of the universe.
Early Life
Stephen William Hawking was born on January 8, 1942, on the three hundredth anniversary of the death of one of the greatest physicists of all time, Galileo Galilei, who is generally credited with proving that the earth revolves around the sun. Hawking’s birth was also only four days after the three hundredth birthday of another great physicist, Isaac Newton, who developed a mathematical model to explain the structure of the universe that was essentially unchallenged for over two hundred years. Hawking was born in Oxford, England, where both of his parents had attended Oxford University. However, the Hawkings had only recently returned to Oxford to escape the likelihood of London being bombed during World War II.
Hawking’s father, Frank, was a physician who had the same ambition for his son. However, Hawking did not find medicine and biology theoretically rich enough and instead decided to major in physics at Oxford. By his own admission, Hawking averaged barely one hour per day of studying at Oxford and decided to concentrate on theoretical physics as a way to avoid the busy work of memorizing facts. After graduating from Oxford, Hawking had hoped to study at Cambridge University with Fred Hoyle, who had developed “steady-state” cosmology, which argues that the structure of the universe remains relatively constant over time. However, his acceptance to Cambridge was contingent upon his receiving honors from Oxford. Because of his lack of studying, his final examination scores at Oxford were only borderline for an honors degree. In an interview, he then told his examiners that if they gave him honors, he would go to Cambridge. Otherwise, he would stay at Oxford. They gave him honors.
Upon reaching Cambridge, Hawking was disappointed to learn that he would not study with Hoyle but Dennis Sciama, another steady-state cosmologist unfamiliar to Hawking. However, Sciama turned out to be much more available and open to students developing their own alternative perspectives than Hoyle would have been. Within a few months of arriving at Cambridge, Hawking faced a far more serious disappointment. Never robust or athletic, Hawking was becoming increasingly clumsy. At his mother’s insistence, he saw a doctor. He was diagnosed with amyotrophic lateral sclerosis (ALS; called Lou Gehrig’s disease in the United States), a degenerative condition causing the patient to gradually lose control of all muscles, including those necessary to move, gesture, speak, and swallow. Hawking was told he might only live another two years and underwent a deep depression as he contemplated the futility of trying to complete his doctorate. Sciama persuaded him to continue but refused to lower his standards. As his condition worsened, Hawking came to need a cane, then a wheelchair, and then an artificial speech synthesizer. However, he went on to survive for many years after he was diagnosed with a terminal condition.
Through Sciama, Hawking met Roger Penrose, a mathematician who had developed the idea of a “singularity,” a point at which the laws of mathematics and science break down. Hawking earned his doctorate by proposing that singularities could be used to understand the structure of the universe. He has since come to rethink the concept of singularity and argue that the laws of physics are continuous throughout the universe.
Life’s Work
Early in the twentieth century, Newton’s physics faced two challenges: relativity, conceived by Albert Einstein, and quantum mechanics, which had several founders....
(This entire section contains 2006 words.)
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Although Einstein contributed to the development of quantum mechanics, he was uncomfortable with it. What most disturbed him was the uncertainty principle of Werner Heisenberg, which suggests that not everything is knowable and measurable. Because Einstein’s relativity insists that everything can ultimately be determined, a position that it shared with Newtonian mechanics, Hawking calls it a “classical theory.” One implication of relativity that Einstein himself shunned was that large stars could collapse into black holes, single points with such overwhelming gravitational strength that nothing, including light, can escape. Penrose considered black holes to be singularities and thought that since they emitted no signals, they were unknowable by the laws of physics as scientists understood them.
In the 1920’s, astronomers began to believe that the universe was expanding. Hoyle’s steady-state cosmology was one model of an expanding universe. However, a rival cosmology emerged to account for the expanding universe, which Hoyle disparagingly dismissed as the “big bang.” The big bang theory proposes that billions of years ago the entire universe was compressed into a single point that exploded. The energy released from that explosion gave birth to the four forces that govern the universe (gravity, electromagnetism, strong nuclear force, and weak nuclear force), elementary particles, atoms, galaxies, stars, and planets. The initial explosion was so strong that it continues to cause the universe to expand to the present day. The big bang hypothesis suggests that residual radiation from that explosion should pervade the cosmos even now. Around the time Hawking wrote his doctoral dissertation, the radiation was discovered. This caused most physicists to reject Hoyle’s steady state. In his dissertation, Hawking suggested that the entire universe was originally a singularity like a black hole and that the big bang could be understood by comparing the universe to a star collapsing into black hole. Hawking’s analogy reversed the time sequence of a compressing star: The universe explodes from a singularity rather than imploding into one.
One of the most serious problems in twentieth century physics is that its two main theories, relativity and quantum mechanics, appear to be incompatible. Black holes are predicted by relativity, which implies that they should emit no energy. In the 1970’s, Hawking began to wonder if he could reconcile relativity and quantum mechanics by applying quantum mechanics to black holes. He found that according to quantum mechanics, black holes would indeed emit energy and would eventually explode. Hence, if the universe prior to the big bang was analogous to a black hole, it would one day burst like a black hole; therefore, the big bang could be explained by combining relativity and quantum mechanics. This means that the primordial universe as well as black holes can be understood by laws of mathematics and science and neither are really singularities. Hawking came to believe that the universe was continuous and governed by a single set of laws. This would not mean that all events were predictable because a comprehensive theory of the universe would still contain Heisenberg’s uncertainty principle. Hawking cautions that even if humans knew all the laws that underlie the operation of the universe, an account of all possible occurrences would require knowing the history of every particle, something clearly impossible within finite time.
Twentieth century physics believes the universe is governed by four forces: gravity (which binds the planets, stars, and galaxies together), electromagnetism (which binds the atom together), the strong nuclear force (which holds the atomic nucleus together), and the weak nuclear force (which is necessary to account for radioactive decay). Einstein spent his later years unsuccessfully searching for a “grand unified theory,” a single set of equations that would account for all four forces. Hawking is convinced that Einstein failed because he did not incorporate quantum mechanics. According to Hawking, the place to look for the grand unified theory is during the big bang, when Hawking and other physicists believe the four forces were one.
The universe assumed the shape it did because of the particular way energy happened to have been distributed at the time of the big bang. With slight differences, the galaxies and stars may never have developed. Indeed, the big bang may have produced regions where space, matter, and energy assumed different forms. Hawking proposed that the result could be an infinite number of “baby universes” and that the universe in which humans live may be only one of many possibilities.
The ultimate fate of the universe may depend upon how much matter it contains. If it contains only the matter that astronomers can see with visible light, then the universe should expand forever. If there is more matter, the universe will eventually contract and ultimately collapse into a single point. Hawking hypothesizes that black holes may have formed not only out of imploding stars but also from residues of the big bang. If that is true, black holes may pervade the universe, and there may be enough invisible matter to one day reverse its expansion. Long after the universe again congeals into a single point, it will again explode and expand. Hence, the universe would have a continual history whose broad outline is predictable. If Hawking is correct, then the dream of physics, a single set of laws to explain the development of the universe and all its contents, is indeed attainable.
Summary
Stephen Hawking considers his own work incomplete. However, as Hawking himself suggests, science is never complete. It is supposed to be self-critical and forever subject to revision. Even if Hawking’s work leads to a reassessment of Einstein, it will not diminish Einstein’s greatness. Einstein caused a rethinking of Newton’s theory, which had served as the foundation of physics for over two centuries. Hawking would have never developed his model had Einstein not preceded him, nor would Einstein have produced relativity without Newton’s prior framework. The ideal of scientists is to build on each other. Today’s truth may become tomorrow’s error, but it is also the foundation of tomorrow’s truth. As Newton admitted, “I can see far because I stand on the shoulders of giants.” Most likely, Hawking will prove to be another layer in a pyramid of giants.
There are critics who charge that Hawking is simply one of a number of scientists trying to unify physics and explain the development of the universe and that his disability is the primary reason he has received so much attention from the media. Even if that were true, the fact that anyone can produce such acclaimed work with an affliction such as his should serve as an inspiration to both the handicapped and the able-bodied. Albert Einstein, Bertrand Russell (who revised mathematics and worked for world peace), and Linus Pauling (who won Nobel Prizes in Physics, Chemistry, and Peace) are remembered not only as great scientists but also as great humanitarians. The same will very likely be true of Stephen Hawking.
Bibliography
Boslough, John. Stephen Hawking’s Universe. New York: Avon, 1985. An introduction to twentieth century cosmology, relativity, quantum mechanics, and Hawking’s contribution to them.
Hawking, Stephen. A Brief History of Time. New York: Bantam, 1988. A popular book that Hawking wrote to explain his own work as part of the development of twentieth century physics. It set a record for the number of weeks on The New York Times Best-Seller List.
Hawking, Stephen. Black Holes and Baby Universes. New York: Bantam, 1993. A collection of popular essays written by Hawking. They discuss his life, his philosophy of science, the possibility of science knowing everything, and the origin, structure, and fate of the universe.
Hawking, Stephen, and Roger Penrose. The Nature of Space and Time. Princeton, N.J.: Princeton University Press, 1966. This is the published edition of a series of debates between Hawking and his former mentor and collaborator, Roger Penrose. They contrast their opinions about black holes, the origin and fate of the university, and the philosophy of science.
McEvoy, J. P., and Oscar Zarate. Introducing Stephen Hawking. New York: Totem, 1997. A comic-book presentation of Hawking’s life and work that is particularly good at mixing graphics and text. In the process of explaining Hawking, it offers an amusing but informative history of twentieth century physics.
White, Michael, and John Gribbin. Stephen Hawking, A Life in Science. New York: Penguin, 1993. A biography of Hawking that shows how his personal history impacted upon his scientific discoveries.