Stephen William Hawking, CH, CBE, FRS, FRSA (i/ˈstiːvən ˈhɔːkɪŋ/; born 8 January 1942) is an English theoretical physicist, cosmologist, author and Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge. His scientific works include a collaboration with Roger Penrose on gravitational singularity theorems in the framework of general relativity and the theoretical prediction that black holes emit radiation, often called Hawking radiation. Hawking was the first to set forth a theory of cosmology explained by a union of the general theory of relativity and quantum mechanics. He is a vigorous supporter of the many-worlds interpretation of quantum mechanics.
Hawking is an Honorary Fellow of the Royal Society of Arts, a lifetime member of the Pontifical Academy of Sciences, and a recipient of the Presidential Medal of Freedom, the highest civilian award in the US. In 2002, Hawking was ranked number 25 in the BBC's poll of the 100 Greatest Britons. He was the Lucasian Professor of Mathematics at the University of Cambridge between 1979 and 2009 and has achieved commercial success with works of popular science in which he discusses his own theories and cosmology in general; his book A Brief History of Time appeared on the British Sunday Times best-seller list for a record-breaking 237 weeks.
Hawking has a rare early-onset, slow-progressing form of amyotrophic lateral sclerosis (ALS) that has gradually paralysed him over the decades. He now communicates using a single cheek muscle attached to a speech-generating device.
Hawking was born on 8 January 1942 in Oxford, England to Frank (1905–1986) and Isobel Hawking (née Walker; 1915–2013). His mother was Scottish. Despite their families' financial constraints, both parents attended the University of Oxford, where Frank read medicine and Isobel read Philosophy, Politics and Economics. The two met shortly after the beginning of the Second World War at a medical research institute where Isobel was working as a secretary and Frank was working as a medical researcher. They lived in Highgate; but, as London was being bombed in those years, Isobel went to Oxford to give birth in greater safety. Hawking has two younger sisters, Philippa and Mary, and an adopted brother, Edward.
In 1950, when Hawking's father became head of the division of parasitology at the National Institute for Medical Research, Hawking and his family moved to St Albans, Hertfordshire. In St Albans, the family were considered highly intelligent and somewhat eccentric; meals were often spent with each person silently reading a book. They lived a frugal existence in a large, cluttered, and poorly maintained house and travelled in a converted London taxicab. During one of Hawking's father's frequent absences working in Africa, the rest of the family spent four months in Majorca visiting his mother's friend Beryl and her husband, the poet Robert Graves.
Hawking began his schooling at the Byron House School in Highgate, London. He later blamed its "progressive methods" for his failure to learn to read while at the school. In St Albans, the eight-year-old Hawking attended St Albans High School for Girls for a few months. At that time, younger boys could attend one of the houses.
Hawking attended Radlett School, an independent school in the village of Radlett in Hertfordshire, for a year, and from September 1952, St Albans School, an independent school in the city of St Albans in Hertfordshire. The family placed a high value on education. Hawking's father wanted his son to attend the well-regarded Westminster School, but the 13-year-old Hawking was ill on the day of the scholarship examination. His family could not afford the school fees without the financial aid of a scholarship, so Hawking remained at St Albans. A positive consequence was that Hawking remained with a close group of friends with whom he enjoyed board games, the manufacture of fireworks, model aeroplanes and boats, and long discussions about Christianity and extrasensory perception. From 1958 on, with the help of the mathematics teacher Dikran Tahta, they built a computer from clock parts, an old telephone switchboard and other recycled components.
Although at school Hawking was known as "Einstein", Hawking was not initially successful academically. With time, he began to show considerable aptitude for scientific subjects and, inspired by Tahta, decided to read mathematics at university.Hawking's father advised him to study medicine, concerned that there were few jobs for mathematics graduates. He wanted Hawking to attend University College, Oxford, his own alma mater. As it was not possible to read mathematics there at the time, Hawking decided to study physics and chemistry. Despite his headmaster's advice to wait until the next year, Hawking was awarded a scholarship after taking the examinations in March 1959.
Hawking began his university education at University College, Oxford in October 1959 at the age of 17. For the first 18 months, he was bored and lonely: he was younger than many other students, and found the academic work "ridiculously easy". His physics tutor, Robert Berman, later said, "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." A change occurred during his second and third year when, according to Berman, Hawking made more effort "to be one of the boys". He developed into a popular, lively and witty college member, interested in classical music and science fiction. Part of the transformation resulted from his decision to join the college boat club, the University College Boat Club, where he coxed a rowing team. The rowing trainer at the time noted that Hawking cultivated a daredevil image, steering his crew on risky courses that led to damaged boats.
Hawking has estimated that he studied about a thousand hours during his three years at Oxford. These unimpressive study habits made sitting his finals a challenge, and he decided to answer only theoretical physics questions rather than those requiring factual knowledge. A first-class honours degree was a condition of acceptance for his planned graduate study in cosmology at the University of Cambridge. Anxious, he slept poorly the night before the examinations, and the final result was on the borderline between first- and second-class honours, making a viva (oral examination) necessary. Hawking was concerned that he was viewed as a lazy and difficult student. So, when asked at the oral to describe his future plans, he said, "If you award me a First, I will go to Cambridge. If I receive a Second, I shall stay in Oxford, so I expect you will give me a First." He was held in higher regard than he believed; as Berman commented, the examiners "were intelligent enough to realise they were talking to someone far cleverer than most of themselves". After receiving a first-class BA (Hons.) degree in natural science; and, following a trip to Iran with a friend, he began his graduate work at Trinity Hall, Cambridge, in October 1962.
Hawking's first year as a doctoral student was difficult. He was initially disappointed to find that he had been assigned Dennis William Sciama, one of the founders of modern cosmology, as a supervisor rather than noted astronomer Fred Hoyle, and he found his training in mathematics inadequate for work in general relativity and cosmology.After being diagnosed with motor neurone disease, Hawking fell into a depression; though his doctors advised that he continue with his studies, he felt there was little point.However, his disease progressed more slowly than doctors had predicted. Although Hawking had difficulty walking unsupported and his speech was almost unintelligible, an initial diagnosis that he had only two years to live proved unfounded. With the encouragement of Sciama, he returned to his work. Hawking started developing a reputation for brilliance and brashness when he publicly challenged the work of Fred Hoyle and his student Jayant Narlikar at a lecture in June 1964.
When Hawking began his graduate studies, there was much debate in the physics community about the prevailing theories of the creation of the universe: the Big Bang and the Steady State theories. Inspired by Roger Penrose's theorem of a spacetime singularity in the centre of black holes, Hawking applied the same thinking to the entire universe; and, during 1965, he wrote his thesis on this topic. There were other positive developments: Hawking received a research fellowship at Gonville and Caius College. He obtained his PhD degree in applied mathematics and theoretical physics, specialising in general relativity and cosmology, in March 1966, and his essay entitled "Singularities and the Geometry of Space-Time" shared top honours with one by Penrose to win that year's prestigious Adams Prize.
In his work, and in collaboration with Penrose, Hawking extended the singularity theorem concepts first explored in his doctoral thesis. This included not only the existence of singularities but also the theory that the universe might have started as a singularity. Their joint essay was the runner-up in the 1968 Gravity Research Foundation competition. In 1970 they published a proof that if the universe obeys the general theory of relativity and fits any of the models of physical cosmology developed by Alexander Friedmann, then it must have begun as a singularity. In 1969, Hawking accepted a specially created Fellowship for Distinction in Science to remain at Caius.
In 1970, Hawking postulated what became known as the second law of black hole dynamics, that the event horizon of a black hole can never get smaller. With James M. Bardeen and Brandon Carter, he proposed the four laws of black hole mechanics, drawing an analogy with thermodynamics. To Hawking's irritation, Jacob Bekenstein, a graduate student of John Wheeler, went further—and ultimately correctly—to apply thermodynamic concepts literally. In the early 1970s, Hawking's work with Carter, Werner Israel and David C. Robinson strongly supported Wheeler's no-hair theorem that no matter what the original material from which a black hole is created, it can be completely described by the properties of mass, electrical charge and rotation. His essay titled "Black Holes" won the Gravity Research Foundation Award in January 1971. Hawking's first book, The Large Scale Structure of Space-Time, written with George Ellis, was published in 1973.
Beginning in 1973, Hawking moved into the study of quantum gravity and quantum mechanics. His work in this area was spurred by a visit to Moscow and discussions with Yakov Borisovich Zel'dovich and Alexei Starobinsky, whose work showed that according to the uncertainty principle, rotating black holes emit particles. To Hawking's annoyance, his much-checked calculations produced findings that contradicted his second law, which claimed black holes could never get smaller, and supported Bekenstein's reasoning about their entropy. His results, which Hawking presented from 1974, showed that black holes emit radiation, known today as Hawking radiation, which may continue until they exhaust their energy and evaporate. Initially, Hawking radiation was controversial. However, by the late 1970s and following the publication of further research, the discovery was widely accepted as a significant breakthrough in theoretical physics. Hawking was elected a Fellow of the Royal Society (FRS) in 1974, a few weeks after the announcement of Hawking radiation. At the time, he was one of the youngest scientists to become a Fellow.
Hawking was appointed to the Sherman Fairchild Distinguished visiting professorship at the California Institute of Technology (Caltech) in 1970. He worked with a friend on the faculty, Kip Thorne, and engaged him in a scientific wager about whether the dark star Cygnus X-1 was a black hole. The wager was an "insurance policy" against the proposition that black holes did not exist. Hawking acknowledged that he had lost the bet in 1990, which was the first of several that he was to make with Thorne and others. Hawking has maintained ties to Caltech, spending a month there almost every year since this first visit.
Hawking returned to Cambridge in 1975 to a more academically senior post, as reader in gravitational physics. The mid- to late 1970s were a period of growing public interest in black holes and of the physicists who were studying them. Hawking was regularly interviewed for print and television. He also received increasing academic recognition of his work. In 1975, he was awarded both the Eddington Medal and the Pius XI Gold Medal, and in 1976 the Dannie Heineman Prize, the Maxwell Prize and the Hughes Medal. He was appointed a professor with a chair in gravitational physics in 1977. The following year he received the Albert Einstein Medal and an honorary doctorate from the University of Oxford.
In the late 1970s, Hawking was elected Lucasian Professor of Mathematics at the University of Cambridge. His inaugural lecture as Lucasian Professor of Mathematics was titled: "Is the End in Sight for Theoretical Physics" and proposed N=8 Supergravity as the leading theory to solve many of the outstanding problems physicists were studying. His promotion coincided with a health crisis which led to his accepting, albeit reluctantly, some nursing services at home. At the same time, he was also making a transition in his approach to physics, becoming more intuitive and speculative rather than insisting on mathematical proofs. "I would rather be right than rigorous", he told Kip Thorne. In 1981, he proposed that information in a black hole is irretrievably lost when a black hole evaporates. This information paradox violates the fundamental tenet of quantum mechanics, and led to years of debate, including "the Black Hole War" with Leonard Susskind and Gerard 't Hooft.
Cosmological inflation—a theory proposing that following the Big Bang, the universe initially expanded incredibly rapidly before settling down to a slower expansion—was proposed by Alan Guth and also developed by Andrei Linde. Following a conference in Moscow in October 1981, Hawking and Gary Gibbons organized a three-week Nuffield Workshop in the summer of 1982 on "The Very Early Universe" at Cambridge University, which focused mainly on inflation theory. Hawking also began a new line of quantum theory research into the origin of the universe. In 1981 at a Vatican conference, he presented work suggesting that there might be no boundary—or beginning or ending—to the universe. He subsequently developed the research in collaboration with Jim Hartle, and in 1983 they published a model, known as the Hartle–Hawking state. It proposed that prior to the Planck epoch, the universe had no boundary in space-time; before the Big Bang, time did not exist and the concept of the beginning of the universe is meaningless. The initial singularity of the classical Big Bang models was replaced with a region akin to the North Pole. One cannot travel north of the North Pole, but there is no boundary there—it is simply the point where all north-running lines meet and end. Initially the no-boundary proposal predicted a closed universe which had implications about the existence of God. As Hawking explained "If the universe has no boundaries but is self-contained... then God would not have had any freedom to choose how the universe began."
Hawking did not rule out the existence of a Creator, asking in A Brief History of Time "Is the unified theory so compelling that it brings about its own existence?" In his early work, Hawking spoke of God in a metaphorical sense. In A Brief History of Time he wrote: "If we discover a complete theory, it would be the ultimate triumph of human reason—for then we should know the mind of God." In the same book he suggested the existence of God was unnecessary to explain the origin of the universe. Later discussions with Neil Turok led to the realisation that it is also compatible with an open universe.
Further work by Hawking in the area of arrows of time led to the 1985 publication of a paper theorising that if the no-boundary proposition were correct, then when the universe stopped expanding and eventually collapsed, time would run backwards. A paper by Don Page and independent calculations by Raymond Laflamme led Hawking to withdraw this concept. Honours continued to be awarded: in 1981 he was awarded the American Franklin Medal, and in 1982 made a Commander of the Order of the British Empire (CBE). Awards do not pay the bills, however, and motivated by the need to finance the children's education and home expenses, in 1982 Hawking determined to write a popular book about the universe that would be accessible to the general public. Instead of publishing with an academic press, he signed a contract with Bantam Books, a mass market publisher, and received a large advance for his book. A first draft of the book, called A Brief History of Time, was completed in 1984.
One of the first messages Hawking produced with his speech-generating device was a request for his assistant to help him finish writing A Brief History of Time. Peter Guzzardi, his editor at Bantam, pushed him to explain his ideas clearly in non-technical language, a process that required multiple revisions from an increasingly irritated Hawking. The book was published in April 1988 in the US and in June in the UK, and proved to be an extraordinary success, rising quickly to the top of bestseller lists in both countries and remaining there for months. The book was translated into multiple languages, and ultimately sold an estimated 9 million copies. Media attention was intense, and Newsweek magazine cover and a television special both described him as "Master of the Universe". Success led to significant financial rewards, but also the challenges of celebrity status. Hawking travelled extensively to promote his work, and enjoyed partying and dancing into the small hours. He had difficulty refusing the invitations and visitors which left limited time for work and his students. Some colleagues were resentful of the attention Hawking received, feeling it was due to his disability. He received further academic recognition, including five further honorary degrees, the Gold Medal of the Royal Astronomical Society (1985), the Paul Dirac Medal (1987) and, jointly with Penrose, the prestigious Wolf Prize (1988). In 1989, he was appointed Member of the Order of the Companions of Honour (CH).He reportedly declined a knighthood.
Hawking pursued his work in physics: in 1993 he co-edited a book on Euclidean quantum gravity with Gary Gibbons and published a collected edition of his own articles on black holes and the Big Bang. In 1994 at Cambridge's Newton Institute, Hawking and Penrose delivered a series of six lectures, which were published in 1996 as "The Nature of Space and Time". In 1997 he conceded a 1991 public scientific wager made with Kip Thorne and John Preskill of Caltech. Hawking had bet that Penrose's proposal of a "cosmic censorship conjecture"—that there could be no "naked singularities" unclothed within a horizon—was correct. After discovering his concession might have been premature, a new, more refined, wager was made. This specified that such singularities would occur without extra conditions. The same year, Thorne, Hawking and Preskill made another bet, this time concerning the black hole information paradox. Thorne and Hawking argued that since general relativity made it impossible for black holes to radiate and lose information, the mass-energy and information carried by Hawking radiation must be "new", and not from inside the black hole event horizon. Since this contradicted the quantum mechanics of microcausality, quantum mechanics theory would need to be rewritten. Preskill argued the opposite, that since quantum mechanics suggests that the information emitted by a black hole relates to information that fell in at an earlier time, the concept of black holes given by general relativity must be modified in some way.
Hawking also maintained his public profile, including bringing science to a wider audience. A film version of A Brief History of Time, directed by Errol Morris and produced by Steven Spielberg, premiered in 1992. Hawking had wanted the film to be scientific rather than biographical, but he was persuaded otherwise. The film, while a critical success, was however not widely released. A popular-level collection of essays, interviews and talk titled Black Holes and Baby Universes and Other Essays was published in 1993and six-part television series Stephen Hawking's Universe and companion book appeared in 1997. As Hawking insisted, this time the focus was entirely on science.
Hawking continued his writings for a popular audience, publishing The Universe in a Nutshell in 2001, and A Briefer History of Time which he wrote in 2005 with Leonard Mlodinow to update his earlier works to make them accessible to a wider audience, and God Created the Integers, which appeared in 2006. Along with Thomas Hertog at CERN and Jim Hartle, from 2006 on Hawking developed a theory of "top-down cosmology", which says that the universe had not one unique initial state but many different ones, and therefore that it is inappropriate to formulate a theory that predicts the universe's current configuration from one particular initial state. Top-down cosmology posits that the present "selects" the past from a superposition of many possible histories. In doing so, the theory suggests a possible resolution of the fine-tuning question.
Hawking continued to travel widely, including trips to Chile, Easter Island, South Africa, Spain (to receive the Fonseca Prize in 2008),Canada, and multiple trips to the United States. For practical reasons related to his disability, Hawking increasingly travelled by private jet, and by 2011 that had become his only mode of international travel.
By 2003, consensus among physicists was growing that Hawking was wrong about the loss of information in a black hole. In a 2004 lecture in Dublin, he conceded his 1997 bet with Preskill, but described his own, somewhat controversial solution, to the information paradox problem, involving the possibility that black holes have more than one topology. In the 2005 paper he published on the subject, he argued that the information paradox was explained by examining all the alternative histories of universes, with the information loss in those with black holes being cancelled out by those without. In January 2014 he called the alleged loss of information in black holes his "biggest blunder".
As part of another longstanding scientific dispute, Hawking had emphatically argued, and bet, that the Higgs boson would never be found. The particle was proposed to exist as part of the Higgs field theory by Peter Higgs in 1964. Hawking and Higgs engaged in a heated and public debate over the matter in 2002 and again in 2008, with Higgs criticising Hawking's work and complaining that Hawking's "celebrity status gives him instant credibility that others do not have." The particle was discovered in July 2012 at CERN following construction of the Large Hadron Collider. Hawking quickly conceded that he had lost his bet and said that Higgs should win the Nobel Prize for Physics, which he did in 2013.
In 2007 Hawking and his daughter Lucy published George's Secret Key to the Universe, a children's book designed to explain theoretical physics in an accessible fashion and featuring characters similar to those in the Hawking family. The book was followed by sequels in 2009, 2011 and 2014.
In 2002, following a UK-wide vote, the BBC included Hawking in their list of the 100 Greatest Britons. He was awarded the Copley Medal from the Royal Society (2006), the Presidential Medal of Freedom which is America's highest civilian honour (2009), and the Russian Special Fundamental Physics Prize (2013).
Several buildings have been named after him, including the Stephen W. Hawking Science Museum in San Salvador, El Salvador, the Stephen Hawking Building in Cambridge, and the Stephen Hawking Centre at Perimeter Institute in Canada. Appropriately, given Hawking's association with time, he unveiled the mechanical "Chronophage" (or time-eating) Corpus Clock at Corpus Christi College Cambridge in September 2008.
During his career Hawking has supervised 39 successful PhD students. As required by Cambridge University regulations, Hawking retired as Lucasian Professor of Mathematics in 2009. Despite suggestions that he might leave the United Kingdom as a protest against public funding cuts to basic scientific research, Hawking has continued to work as director of research at the Cambridge University Department of Applied Mathematics and Theoretical Physics, and indicated in 2012 that he had no plans to retire.
On June 28, 2009, as a tongue-in-cheek test of his 1992 conjecture that travel into the past is effectively impossible, Hawking held a party open to all, complete with hors d'oeuvres and iced champagne, but only publicized the party after it was over so that only time-travellers would know to attend; as expected, nobody showed up to the party.
On 20 July 2015, Hawking helped launch Breakthrough Initiatives, an effort to search for extraterrestrial life. In 2015, Richard Branson offered Stephen Hawking a seat on the Virgin Galactic spaceship for free. While no hard date has been set for launch, Virgin Galactic’s SpaceShipTwo is slated to launch at the end of 2017. At 75, Hawking will not be the oldest person to ever go to space (John Glenn returned to space at age 77), but he will be the first person to go to space with amyotrophic lateral sclerosis (ALS). While this will be Hawking’s first time in space, it won’t be the first time he’ll experience weightlessness. In 2007, he flew into zero gravity aboard a specially-modified Boeing 727-200 aircraft.
When Hawking was a graduate student at Cambridge, his relationship with Jane Wilde, a friend of his sister, whom he had met shortly before his diagnosis with motor neurone disease, continued to develop. The couple became engaged in October 1964—Hawking later said that the engagement gave him "something to live for"—and the two were married on 14 July 1965.
During their first years of marriage, Jane lived in London during the week as she completed her degree, and they travelled to the United States several times for conferences and physics-related visits. The couple had difficulty finding housing that was within Hawking's walking distance to the Department of Applied Mathematics and Theoretical Physics (DAMTP). Jane began a PhD programme, and a son, Robert, was born in May 1967. A daughter, Lucy, was born in 1970. A third child, Timothy, was born in April 1979.
Hawking rarely discussed his illness and physical challenges, even—in a precedent set during their courtship—with Jane. His disabilities meant that the responsibilities of home and family rested firmly on his wife's increasingly overwhelmed shoulders, leaving him more time to think about physics. Upon his appointment in 1974 to a year-long position at the California Institute of Technology in Pasadena, California, Jane proposed that a graduate or post-doctoral student live with them and help with his care. Hawking accepted, and Bernard Carr travelled with them as the first of many students who fulfilled this role. The family spent a generally happy and stimulating year in Pasadena.
Hawking returned to Cambridge in 1975 to a new home and a new job, as reader. Don Page, with whom Hawking had begun a close friendship at Caltech, arrived to work as the live-in graduate student assistant. With Page's help and that of a secretary, Jane's responsibilities were reduced so she could return to her thesis and her new interest in singing.
By December 1977, Jane had met organist Jonathan Hellyer Jones when singing in a church choir. Hellyer Jones became close to the Hawking family, and by the mid-1980s, he and Jane had developed romantic feelings for each other. According to Jane, her husband was accepting of the situation, stating "he would not object so long as I continued to love him." Jane and Hellyer Jones determined not to break up the family and their relationship remained platonic for a long period.
By the 1980s, Hawking's marriage had been strained for many years. Jane felt overwhelmed by the intrusion into their family life of the required nurses and assistants. The impact of his celebrity was challenging for colleagues and family members, while the prospect of living up to a worldwide fairytale image was daunting for the couple.Hawking's views of religion also contrasted with her strong Christian faith and resulted in tension. In the late 1980s, Hawking had grown close to one of his nurses, Elaine Mason, to the dismay of some colleagues, caregivers and family members, who were disturbed by her strength of personality and protectiveness. Hawking told Jane that he was leaving her for Mason and departed the family home in February 1990. After his divorce from Jane in 1995, Hawking married Mason in September,declaring "It's wonderful—I have married the woman I love."
In 1999, Jane Hawking published a memoir, Music to Move the Stars, describing her marriage to Hawking and its breakdown. Its revelations caused a sensation in the media, but as was his usual practice regarding his personal life, Hawking made no public comment except to say that he did not read biographies about himself. After his second marriage, Hawking's family felt excluded and marginalised from his life. For a period of about five years in the early 2000s, his family and staff became increasingly worried that he was being physically abused. Police investigations took place, but were closed as Hawking refused to make a complaint.
In 2006, Hawking and Mason quietly divorced, and Hawking resumed closer relationships with Jane, his children, and grandchildren. Reflecting this happier period, a revised version of Jane's book called Travelling to Infinity: My Life with Stephen appeared in 2007, and was made into a film, The Theory of Everything, in 2014.
Hawking has a rare early-onset slow-progressing form of amyotrophic lateral sclerosis (ALS), also known as motor neurone disease or Lou Gehrig's disease, that has gradually paralysed him over the decades.
Hawking had experienced increasing clumsiness during his final year at Oxford, including a fall on some stairs and difficulties when rowing. The problems worsened, and his speech became slightly slurred; his family noticed the changes when he returned home for Christmas, and medical investigations were begun. The diagnosis of motor neurone disease came when Hawking was 21, in 1963. At the time, doctors gave him a life expectancy of two years.
In the late 1960s, Hawking's physical abilities declined: he began to use crutches and ceased lecturing regularly. As he slowly lost the ability to write, he developed compensatory visual methods, including seeing equations in terms of geometry. The physicist Werner Israel later compared the achievements to Mozart composing an entire symphony in his head. Hawking was, however, fiercely independent and unwilling to accept help or make concessions for his disabilities. He preferred to be regarded as "a scientist first, popular science writer second, and, in all the ways that matter, a normal human being with the same desires, drives, dreams, and ambitions as the next person." His wife Jane Hawking later noted that "Some people would call it determination, some obstinacy. I've called it both at one time or another." He required much persuasion to accept the use of a wheelchair at the end of the 1960s, but ultimately became notorious for the wildness of his wheelchair driving. Hawking was a popular and witty colleague, but his illness, as well as his reputation for brashness, distanced him from some.
Hawking's speech deteriorated, and by the late 1970s he could be understood by only his family and closest friends. To communicate with others, someone who knew him well would translate his speech into intelligible speech. Spurred by a dispute with the university over who would pay for the ramp needed for him to enter his workplace, Hawking and his wife campaigned for improved access and support for those with disabilities in Cambridge, including adapted student housing at the university. In general, however, Hawking had ambivalent feelings about his role as a disability rights champion: while wanting to help others, he sought to detach himself from his illness and its challenges. His lack of engagement led to some criticism.
During a visit to CERN on the border of France and Switzerland in mid-1985, Hawking contracted pneumonia, which in his condition was life-threatening; he was so ill that Jane was asked if life support should be terminated. She refused but the consequence was a tracheotomy, which would require round-the-clock nursing care, and remove what remained of his speech. The National Health Service would pay for a nursing home, but Jane was determined that he would live at home. The cost of the care was funded by an American foundation. Nurses were hired for the three shifts required to provide the round-the-clock support he required. One of those employed was Elaine Mason, who was to become Hawking's second wife.
For his communication, Hawking initially raised his eyebrows to choose letters on a spelling card. But in 1986 he received a computer program called the "Equalizer" from Walter Woltosz, CEO of Words Plus, who had developed an earlier version of the software to help his mother-in-law, who also suffered from ALS and had lost her ability to speak and write. In a method he uses to this day, Hawking could now simply press a switch to select phrases, words or letters from a bank of about 2,500–3,000 that are scanned. The program was originally run on a desktop computer. However, Elaine Mason's husband, David, a computer engineer, adapted a small computer and attached it to his wheelchair. Released from the need to use somebody to interpret his speech, Hawking commented that "I can communicate better now than before I lost my voice." The voice he uses has an American accent and is no longer produced. Despite the availability of other voices, Hawking has retained this original voice, saying that he prefers it and identifies with it. At this point, Hawking activated a switch using his hand and could produce up to 15 words a minute. Lectures were prepared in advance and were sent to the speech synthesiser in short sections to be delivered.
Hawking gradually lost the use of his hand, and in 2005 he began to control his communication device with movements of his cheek muscles, with a rate of about one word per minute. With this decline there is a risk of his developing locked-in syndrome, so Hawking collaborated with Intel researchers on systems that could translate his brain patterns or facial expressions into switch activations. After several prototypes that did not perform as planned, they finally settled on an adaptive word predictor made by the London-based startup SwiftKey, which utilized a system similar to his original technology, so Hawking could adapt to it easier than a brand new complex system, and after inputting large amounts of Hawking's papers and other written materials, developed a satisfactory system that saves time by predicting words and phrases he uses frequently, similar to typing software used on most smartphones today. By 2009 he could no longer drive his wheelchair independently, but the same people who created his new typing mechanics are working on a method to drive his chair using movements made by his chin. This has proven difficult, since Hawking can not move his neck, and trials have shown that while he can indeed drive the chair, the movement is sporadic and jumpy. He has increased breathing difficulties, requiring a ventilator at times and has been hospitalised several times.
Since the 1990s, Hawking has accepted the mantle of role model for disabled people, lecturing and participating in fundraising activities. At the turn of the century, he and eleven other luminaries signed the Charter for the Third Millennium on Disability which called on governments to prevent disability and protect disability rights. In 1999, Hawking was awarded the Julius Edgar Lilienfeld Prize of the American Physical Society. Motivated by the desire to increase public interest in spaceflight and to show the potential of people with disabilities, in 2007 he participated in zero-gravity flight in a "Vomit Comet", courtesy of Zero Gravity Corporation, during which he experienced weightlessness eight times.
In August 2012, Hawking narrated the "Enlightenment" segment of the 2012 Summer Paralympics opening ceremony in London.In 2013, the biographical documentary film Hawking, in which Hawking himself is featured, was released. In September 2013, he expressed support for the legalisation of assisted suicide for the terminally ill. In August 2014, Hawking accepted the Ice Bucket Challenge to promote ALS/MND awareness and raise contributions for research. As he had pneumonia in 2013, he was advised not to have ice poured over him, but his children volunteered to accept the challenge on his behalf.
In 2006 Hawking posed an open question on the Internet: "In a world that is in chaos politically, socially and environmentally, how can the human race sustain another 100 years?", later clarifying: "I don’t know the answer. That is why I asked the question, to get people to think about it, and to be aware of the dangers we now face."
Hawking has expressed concern that life on Earth is at risk from a sudden nuclear war, a genetically engineered virus, global warming, or other dangers we have not yet thought of. However, such a planet-wide disaster need not result in human extinction if the human race were to be able to colonize additional planets before the disaster. Hawking views spaceflight and the colonization of space as necessary for the future of humanity.
Hawking has stated that, given the vastness of the universe, aliens likely exist, but that contact with them should be avoided. He warned that aliens might pillage Earth for resources. In 2010 he said, "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans."
Hawking has warned superintelligent artificial intelligence could be pivotal in steering humanity's fate, stating that "the potential benefits are huge... Success in creating AI would be the biggest event in human history. It might also be the last, unless we learn how to avoid the risks."
Hawking has argued that computer viruses should be considered a new form of life, and has stated that "maybe it says something about human nature, that the only form of life we have created so far is purely destructive. Talk about creating life in our own image."
At Google's Zeitgeist Conference in 2011, Hawking said that "philosophy is dead". He believes that philosophers "have not kept up with modern developments in science" and that scientists "have become the bearers of the torch of discovery in our quest for knowledge". He said that philosophical problems can be answered by science, particularly new scientific theories which "lead us to a new and very different picture of the universe and our place in it".
Hawking has stated that he is "not religious in the normal sense" and he believes that "the universe is governed by the laws of science". Hawking stated:
There is a fundamental difference between religion, which is based on authority, [and] science, which is based on observation and reason. Science will win because it works.
"The laws may have been decreed by God, but God does not intervene to break the laws". In an interview published in The Guardian, Hawking regarded the concept of heaven as a myth, believing that there is "no heaven or afterlife" and that such a notion was a "fairy story for people afraid of the dark". In 2011, when narrating the first episode of the American television series Curiosity on the Discovery Channel, Hawking declared:
We are each free to believe what we want and it is my view that the simplest explanation is there is no God. No one created the universe and no one directs our fate. This leads me to a profound realization. There is probably no heaven, and no afterlife either. We have this one life to appreciate the grand design of the universe, and for that, I am extremely grateful.
In September 2014 he joined Starmus Festival as keynote speaker and declared himself an atheist. In an interview with El Mundo, he commented:
Before we understand science, it is natural to believe that God created the universe. But now science offers a more convincing explanation. What I meant by 'we would know the mind of God' is, we would know everything that God would know, if there were a God, which there isn't. I'm an atheist.
In March 1968, Hawking marched alongside Tariq Ali and Vanessa Redgrave to protest against the Vietnam War. He is a longstanding Labour Party supporter. He recorded a tribute for the 2000 Democratic presidential candidate Al Gore, called the 2003 invasion of Iraq a "war crime", was part of an academic boycott of a conference in Israel because of concerns about Israel's policies towards Palestinians, campaigned for nuclear disarmament, and has supported stem cell research, universal health care, and action to prevent climate change. In August 2014, Hawking was one of 200 signatories to a letter opposing Scottish independence in the run-up to September's referendum on that issue. Hawking believes a United Kingdom withdrawal from the European Union (Brexit) will damage the UK's contribution to science as modern research needs international collaboration, and that free movement of people in Europe encourages the spread of ideas. Hawking is greatly concerned over health care, he stated:
I have received excellent medical attention in Britain, and I felt it was important to set the record straight. I believe in universal health care. And I am not afraid to say so.
At the release party for the home video version of the A Brief History of Time, Leonard Nimoy, who had played Spock on Star Trek, learned that Hawking was interested in appearing on the show. Nimoy made the necessary contact, and Hawking played a holographic simulation of himself in an episode of Star Trek: The Next Generation in 1993. The same year, his synthesiser voice was recorded for the Pink Floyd song "Keep Talking", and in 1999 for an appearance on The Simpsons.Hawking appeared in documentaries entitled The Real Stephen Hawking (2001), Stephen Hawking: Profile (2002)  and Hawking (2013), and the documentary series Stephen Hawking, Master of the Universe (2008). Hawking has also guest-starred in Futurama and The Big Bang Theory.
Hawking allowed the use of his copyrighted voice in the biographical 2014 film The Theory of Everything, in which he was portrayed by Eddie Redmayne in an Academy Award-winning role. Hawking was featured at the Monty Python Live (Mostly) in 2014. He was shown to sing an extended version of the Galaxy Song, after running down Brian Cox with his wheelchair, in a pre-recorded video.
Hawking has used his fame to advertise products, including a wheelchair, National Savings, British Telecom, Specsavers, Egg Banking, and Go Compare. He has applied to trademark his name.
Hawking has received numerous awards and honours. Already early in the list, in 1974 he was elected a Fellow of the Royal Society (FRS). At that time, his nomination read:
Hawking has made major contributions to the field of general relativity. These derive from a deep understanding of what is relevant to physics and astronomy, and especially from a mastery of wholly new mathematical techniques. Following the pioneering work of Penrose he established, partly alone and partly in collaboration with Penrose, a series of successively stronger theorems establishing the fundamental result that all realistic cosmological models must possess singularities. Using similar techniques, Hawking has proved the basic theorems on the laws governing black holes: that stationary solutions of Einstein's equations with smooth event horizons must necessarily be axisymmetric; and that in the evolution and interaction of black holes, the total surface area of the event horizons must increase. In collaboration with G. Ellis, Hawking is the author of an impressive and original treatise on "Space-time in the Large".
The citation continues:
Other important work by Hawking relates to the interpretation of cosmological observations and to the design of gravitational wave detectors.
Hawking received the 2015 BBVA Foundation Frontiers of Knowledge Award in Basic Sciences shared with Viatcheslav Mukhanov for discovering that the galaxies were formed from quantum fluctuations in the early Universe. At the 2016 Pride of Britain Awards, Hawking received the lifetime achievement award "for his contribution to science and British culture".