Hawking, Stephen William, 1942–, British theoretical physicist, b. Oxford, England, grad. University College, Oxford, 1962, Ph.D. Trinity Hall, Cambridge, 1966. In 1962 Hawking was diagnosed as having an incurable muscular disease, amyotrophic lateral sclerosis (ALS). Although the disease eventually confined him to a wheelchair and forced him to use a computer-generated voice synthesizer to communicate, he continued to teach and to lecture at Cambridge, where he was Lucasian professor of mathematics (1979–2009), and began his research in cosmology. In 1971 Hawking provided mathematical support for the big-bang theory of the origin of the universe; he showed that if the general theory of relativity was correct the universe must have a singularity, or starting point, in space-time.

This cosmological thread led him to the study of black holes and his suggestion that following the big bang primordial, or mini, black holes—objects of immense mass occupying only the space of an elementary particle—were formed. He also showed that the surface area of a black hole can increase but never decrease, that there is a limit on the radiation emitted when black holes collide, and that a single black hole cannot cleave into two black holes. In 1974 Hawking calculated that black holes thermally create and emit subatomic particles until they exhaust their energy and explode. This so-called Hawking radiation linked gravity, quantum mechanics, and thermodynamics mathematically for the first time. Hawking proposed in 1981 that although the universe has no boundary, it is finite in space-time; he collaborated with James Hartle to formulate this mathematically in 1983.

Hawking wrote an explanation of his work that became a popular best seller, *A Brief History of Time: From the Big Bang to Black Holes* (1988). He has also published *Superspace and Supergravity* (1981), *The Very Early Universe* (1983), *Black Holes and Baby Universes and Other Essays* (1993), *The Nature of Space and Time* (1995), and *The Grand Design* (with L. Mlodinow, 2010).

See M. White, *Stephen Hawking: A Life in Science* (1992); D. Wilkenson, *God, the Big Bang, and Stephen Hawking* (1993); M. McDaniel, *Stephen Hawking: Revolutionary Physicist* (1994); K. Ferguson, *Stephen Hawking: An Unfettered Mind* (2012).

*The Columbia Electronic Encyclopedia,* 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

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