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Stephen William Hawking, CH, CBE, FRS, FRSA, (born 8 January1942) is a British theoretical physicist. Hawking is the Lucasian Professor of Mathematics at the University of Cambridge, and a Fellow of Gonville and Caius College, Cambridge. He is known for his contributions to the fields of cosmology and quantum gravity, especially in the context of black holes, and his popular works in which he discusses his own theories and cosmology in general. These include the runaway popular science bestseller A Brief History of Time, which stayed on the British Sunday Times bestseller list for a record-breaking 237 weeks.[1] His scientific contributions to date have included providing, with Roger Penrose, theorems regarding singularities in the framework of general relativity, and the theoretical discovery that black holes emit radiation, which is today known as Hawking radiation (or sometimes as Bekenstein-Hawking radiation).[2] His scientific career spans more than forty years and his books and public appearances have made him an academic celebrity and world-renowned theoretical physicist. He is an Honorary Fellow of the Society of Arts.[3]
Biography
In 1950, Hawking and his family moved to St Albans in Hertfordshire where, from the age of 11, he attended St Albans School, where he was a good but not exceptional student.[4] He maintains his connection with the school, giving his name to one of the four houses and to an extra-curricular science lecture series. He has visited to deliver one of the lectures and has also granted a lengthy interview to pupils working on the school magazine, the Albanian. He was always interested in science.[4] He enrolled at University College, Oxford with the intent of studying mathematics, but after his first year was persuaded by his father to switch to physics. His interests during this time were in thermodynamics, relativity, and quantum mechanics. His physics tutor, Robert Berman, later said in the New York Times Magazine, "It was only necessary for him to know that something could be done, and he could do it without looking to see how other people did it. ... He didn't have very many books, and he didn't take notes. Of course, his mind was completely different from all of his contemporaries."[4] He was passing with his fellow students, but his unimpressive study habits gave him a final examination score on the borderline between first and second class honours, making an "oral examination" necessary. Berman said of the oral examination, "And of course the examiners then were intelligent enough to realise they were talking to someone far more clever than most of themselves."[4] After receiving his B.A. degree at Oxford University in 1962, he stayed to study astronomy, deciding to leave when he found that studying sunspots, which was all the observatory was equipped for, didn't appeal to him and that he was more interested in theory than in observation.[4] He left Oxford for Trinity Hall, Cambridge, where he engaged in the study of theoretical astronomy and cosmology.
Jane Wilde, Hawking's first wife, with whom he had three children, cared for him until 1991 when the couple separated, reportedly due to the pressures of fame and his increasing disability. Hawking married his nurse Elaine Mason in 1995. (Elaine Mason's first husband, David Mason, had designed the first version of Hawking's talking computer). In October 2006, the Hawkings filed for divorce.[5] In 1999, Jane Hawking published a memoir, Music to Move the Stars, detailing her own long-term relationship with a family friend whom she later married. Hawking's daughter Lucy Hawking is a novelist. Their son Robert Hawking emigrated to the United States, married, and has one child, George Edward Hawking. Hawking was elected as one of the youngest Fellows of the Royal Society in 1974, was created a Commander of the Order of the British Empire in 1982, and became a Companion of Honour in 1989. Prof. Hawking is a member of the Board of Sponsors of The Bulletin of the Atomic Scientists. At the celebration of his 65th birthday on January 8, 2007, Hawking announced he plans for a zero-gravity flight in 2007 to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Billionaire Richard Branson pledged to pay all expenses for the flight, costing an estimated $200,000.[6] Research fields
Hawking's principal fields of research are theoretical cosmology and quantum gravity. In the late 1960s, he and his Cambridge friend and colleague, Roger Penrose, applied a new, complex mathematical model they had created from Albert Einstein's general theory of relativity. This led, in 1970, to Hawking proving the first of many singularity theorems; such theorems provide a set of sufficient conditions for the existence of a singularity in space-time. This work showed that, far from being mathematical curiosities which appear only in special cases, singularities are a fairly generic feature of general relativity.[7] He supplied a mathematical proof, along with Brandon Carter, W. Israel and D. Robinson, of John Wheeler’s "No-Hair Theorem" — namely, that any black hole is fully described by the three properties of mass, angular momentum, and electric charge. Hawking also suggested that, upon analysis of gamma ray emissions, after the Big Bang, primordial or mini black holes were formed. With Bardeen and Carter, he proposed the four laws of black hole mechanics, drawing an analogy with thermodynamics. In 1974, he calculated that black holes should thermally create and emit subatomic particles, known as Hawking radiation, until they exhaust their energy and evaporate.[8] In collaboration with Jim Hartle, Hawking developed a model in which the Universe had no boundary in space-time, replacing the initial singularity of the classical Big Bang models with a region akin to the North pole; while one cannot travel North of the North pole, there is no boundary there. While originally the no-boundary proposal predicted a closed Universe, discussions with Neil Turok led to the realisation that the no-boundary proposal is consistent with a Universe which is not closed also. Among Hawking's many other scientific investigations, included are the study of: quantum cosmology, cosmic inflation, helium production in anisotropic Big Bang universes, large N cosmology, the density matrix of the universe, topology and structure of the universe, baby universes, Yang-Mills instantons and the S matrix; anti de Sitter space, quantum entanglement and entropy; the nature of space and time, including the arrow of time; spacetime foam, string theory, supergravity, Euclidean quantum gravity, the gravitational Hamiltonian; Brans-Dicke and Hoyle-Narlikar theories of gravitation; gravitational radiation, and wormholes. Losing an old betHawking was in the news in July 2004 for presenting a new theory about black holes which goes against his own long-held belief about their behavior, thus losing a bet he made with Kip Thorne and John Preskill of Caltech. Classically, it can be shown that information crossing the event horizon of a black hole is lost to our universe, and that thus all black holes are identical beyond their mass, electrical charge and angular velocity (the "no hair theorem"). The problem with this theorem is that it implies the black hole will emit the same radiation regardless of what goes into it, and as a consequence that if a pure quantum state is thrown into a black hole, an "ordinary" mixed state will be returned. This runs counter to the rules of quantum mechanics and is known as the black hole information paradox. Hawking had earlier speculated that the singularity at the centre of a black hole could form a bridge to a "baby universe" into which the lost information could pass; such theories have been very popular in science fiction. But according to Hawking's new idea, presented at the 17th International Conference on General Relativity and Gravitation, on 21 July, 2004 in Dublin, Ireland, black holes eventually transmit, in a garbled form, information about all matter they swallow: The Euclidean path integral over all topologically trivial metrics can be done by time slicing and so is unitary when analytically continued to the Lorentzian. On the other hand, the path integral over all topologically non-trivial metrics is asymptotically independent of the initial state. Thus the total path integral is unitary and information is not lost in the formation and evaporation of black holes. The way the information gets out seems to be that a true event horizon never forms, just an apparent horizon.[9] Having concluded that information is conserved, Hawking conceded his bet in Preskill's favour, awarding him Total Baseball, The Ultimate Baseball Encyclopedia. Thorne, however, remained unconvinced of Hawking's proof and declined to contribute to the award.[10] Another older bet — about the existence of black holes — was described by Hawking as an "insurance policy" of sorts. To quote from his book, A Brief History of Time:
According to the updated 10th anniversary edition of A Brief History of Time, Hawking has conceded the bet "to the outrage of Kip's liberated wife" due to subsequent observational data in favor of black holes. IllnessHawking is severely disabled by amyotrophic lateral sclerosis, or ALS (a type of motor neuron disease.); this condition is commonly known in the United States as Lou Gehrig's Disease. When he was young, he enjoyed riding horses and playing with the other children. At Oxford, he coxed a rowing team, which, he stated, helped relieve his immense boredom at the university. Symptoms of the disorder first appeared while he was enrolled at Cambridge. He lost balance and fell downstairs, hitting his head. Worried of losing his genius, he took the Mensa International test to verify that his intellectual abilities were intact. Diagnosis came when Hawking was 21, shortly before his first marriage, and doctors said he would not survive more than two or three years. He gradually lost the use of his arms, legs, and voice, and is now almost completely paralyzed. The computer system attached to his wheelchair is operated by Hawking via an infra-red 'blink switch' clipped onto his glasses. By scrunching his right cheek up, he is able to talk, compose speeches, research papers, browse the World Wide Web, and write e-mails. The system also uses radio transmission to provide control over doors in his home and office. During a visit to the research centre CERN in Geneva in 1985, Hawking contracted pneumonia, which in his condition was life-threatening. It resulted in acute difficulty of breathing, which could only be overcome through a tracheotomy by which Stephen Hawking lost his natural speech ability. He has since used an electronic voice synthesizer to communicate. The voice synthesizer, which has an American accent, is of a model that is no longer produced. Asked why he has still kept it after so many years, Hawking mentioned that he has not heard a voice he likes better and because he identifies with it. Hawking is said to be looking for a replacement since, other than being obsolete, the synthesizer, a DECtalk DTC01 is now considered large and fragile but as of present, finding a software alternative has been difficult. During a lecture in Hong Kong in June 2006, he joked that if he got a new one with a French accent, his wife would divorce him. When Hawking (then using a wheelchair and unable to dress himself) and his wife were first living together, they received no outside assistance other than from physics students who helped in exchange for extra attention with their work. As his condition worsened, Hawking needed a team of nurses to provide round-the-clock care. He also needed a wheelchair for mobility. Despite his disease, he describes himself as "lucky" — not only has the slow progress of his disease provided time to make influential discoveries, it has also afforded time to have, in his own words, "a very attractive family".[11] When Jane was asked why she decided to marry a man with a 3-year life expectancy, she responded: "These were the days of atomic gloom and doom, so we all had a rather short life expectancy." ComputerHawking receives a new computer every 18-24 months donated by Intel. The most recent computer was donated in April of 2005 and is based on the Centrino chipset. It consists of two pieces, a rear chassis which houses 3 160Whr batteries and various external peripherals, and a front chassis, which houses a Tablet-PC and the speakers which project his hardware-synthesized voice. The two chassis are connected via a custom-designed umbilical cable which allows power and electrical signals to travel back and forth. Hawking's computer can run for up to 16 hours without needing a recharge. The computer utilizes a wireless data card that runs on mobile phone networks. This allows Hawking to check his email and browse the web while away from a wireless LAN network. Hawking can also make and receive voice phone calls via a mobile phone with an external microphone in front of his computer speakers. Distinctions
Comments on the future of earth and humanityHawking has made several comments suggesting that the human race may become extinct within the next thousand years. "unless we spread into space ... [as] there are too many accidents that can befall life on a single planet."[2] In the third week of June 2006, Stephen Hawking spoke in China and made the statement that humans might have already damaged the atmosphere and inadvertently reconnected the planet Earth with her dead neighbors.[citation needed] The China Daily asked Hawking about the environment, and he responded that he was "very worried about global warming." He said he was afraid that Earth "might end up like Venus, at 250 degrees Celsius and raining sulphuric acid."[14] In the light of this discussion Hawking asked an open question on Yahoo Answers "How can the human race survive the next hundred years?" and received well over 25,000 responses. The validity of the question was confirmed by Hawking himself and the Yahoo Answers staff.[3] In an ABC News interview in August 2006, Hawking explained, "The danger is that global warming may become self-sustaining, if it has not done so already. The melting of the Arctic and Antarctic ice caps reduces the fraction of solar energy reflected back into space, and so increases the temperature further. Climate change may kill off the Amazon and other rain forests, and so eliminate one of the main ways in which carbon dioxide is removed from the atmosphere. The rise in sea temperature may trigger the release of large quantities of methane, trapped as hydrates on the ocean floor. Both these phenomena would increase the greenhouse effect, and so further global warming. We have to reverse global warming urgently, if we still can." Hawking has also warned of the continued danger posed by nuclear weapons to human survival, saying that "Since Hiroshima and Nagasaki, no nuclear weapons have been used in war, though the world has come uncomfortably close to disaster on more than one occasion," and that "But for good luck, we would all be dead." Hawking concluded that "We foresee great perils if governments and society do not take action now to render nuclear weapons obsolete and prevent further climate change." Professor Hawking has expressed his opposition to plans to replace the Trident nuclear weapons system by the UK government, stating that "Nuclear war remains the greatest danger to the survival of the human race. To replace Trident would make it more difficult to get arms reduction. It would also be a waste of money because there are no circumstances in which we would use it independently."[15] Selected publicationsTechnical
Popular
Footnote: On Hawking's website, he denounces the unauthorized publication of The Theory of Everything and asks consumers to be aware that he was not involved in its creation. Films and seriesFull lists of Hawking's publications are available on his website.[4] Awards
Media AppearancesHawking has appeared as himself on many television shows. For example, he has played himself on a Red Dwarf anniversary special, played a hologram of himself on an episode of Star Trek: The Next Generation, appeared in a skit on Late Night with Conan O'Brien, and appeared on the Discovery Channel special Alien Planet.[16] He has also "played" himself in three episodes of The Simpsons, one episode of Futurama, two episodes of Family Guy, and one episode of The Fairly Odd Parents. His name is mentioned in the song White and Nerdy by Weird Al Yankovic. His actual synthesizer voice was used on parts of the Pink Floyd song Keep Talking from the Division Bell Album of 1994. See alsoNotes and references
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