Hawking's scientific works included a collaboration withRoger Penrose ongravitational singularity theorems in the framework of general relativity, and the theoretical prediction thatblack holes emitradiation, often calledHawking radiation. Initially, Hawking radiation was controversial. By the late 1970s, and following the publication of further research, the discovery was widely accepted as a major breakthrough in theoretical physics. Hawking was the first to set out a theory of cosmology explained by a union of the general theory of relativity andquantum mechanics. Hawking was a vigorous supporter of themany-worlds interpretation of quantum mechanics.[23][24] He also introduced the notion of amicro black hole.[25]
Hawking with his parents Frank (left) and Isobel (right)
Stephen William Hawking was born on 8 January 1942[27][28] inOxford to Frank and Isobel Eileen Hawking (née Walker).[29][30] Hawking's mother was born into a family of doctors inGlasgow, Scotland.[31][32] His wealthy paternal great-grandfather, fromYorkshire, over-extended himself buying farm land and then went bankrupt in thegreat agricultural depression during the early 20th century.[32] His paternal great-grandmother saved the family from financial ruin by opening a school in their home.[32] Despite their families' financial constraints, both parents attended theUniversity of Oxford, where Frank read medicine and Isobel readPhilosophy, Politics and Economics.[30] Isobel worked as a secretary for a medical research institute, and Frank was a medical researcher specialising intropical diseases.[26] Hawking said of his father, "I modelled myself on him. Because he was a scientific researcher, I felt that scientific research was the natural thing to do when one grew up. The only difference was that I was not attracted to medicine or biology because they seemed too inexact and descriptive. I wanted something more fundamental, and I found it in physics."[33]
In 1950, when Hawking's father became head of the division ofparasitology at theNational Institute for Medical Research, the family moved toSt Albans, Hertfordshire.[34][35] There, the family was considered highly intelligent and somewhateccentric;[34][36] meals were often spent with each person silently reading a book.[34] They lived a frugal existence in a large, cluttered, and poorly maintained house and travelled in a convertedLondon taxicab.[37][38] During one of Hawking's father's frequent absences working in Africa,[39] the rest of the family spent four months inMallorca visiting his mother's friend Beryl and her husband, the poetRobert Graves.[40]
Hawking attended twoprivate (i.e. fee-paying) schools, first Radlett School[42] and from September 1952,St Albans School, Hertfordshire,[28][43] after passing theeleven-plus a year early.[44] The family placed a high value on education.[34] Hawking's father wanted his son to attendWestminster 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.[45][46] A positive consequence was that Hawking remained close to a group of friends with whom he enjoyed board games, the manufacture of fireworks,model aeroplanes andboats,[47] and long discussions about Christianity andextrasensory perception.[48] From 1958 on, with the help of the mathematics teacherDikran Tahta, they built a computer from clock parts, an oldtelephone switchboard and other recycled components.[49][50] In 1959, he built a record player from spare parts: "My father would have regarded it as recklessly self-indulgent, to buy a record player, but I persuaded him that I could assemble one from parts that I could buy cheap. That appealed to him as a Yorkshireman."[33]
Although known at school as "Einstein", Hawking was not initially successful academically.[51] With time, he began to show considerable aptitude for scientific subjects and, inspired by Tahta, decided to study mathematics at university.[52][53][54] Hawking's father advised him to study medicine, concerned that there were few jobs for mathematics graduates.[55] He also wanted his son to attendUniversity College, Oxford, his ownalma 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.[56][57]
Undergraduate years
In October 1959, at the age of 17, Hawking began his university education at University College, Oxford.[28][58] For the first eighteen months, he was bored and lonely – he found the academic work "ridiculously easy".[59][60] 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."[2] A change occurred during his second and third years when, according to Berman, Hawking made more of an effort "to be one of the boys". He developed into a popular, lively, and witty student, interested in classical music and science fiction.[58] This partially resulted from his decision to join Oxford'sUniversity College Boat Club, where hecoxed arowing crew.[61][62] The rowing coach at the time noted that Hawking cultivated a daredevil image, steering his crew on risky courses that led to damaged boats.[61][63] Hawking estimated that he studied about 1,000 hours during his three years at Oxford. These unimpressive study habits made sitting hisfinals a challenge, and he decided to answer onlytheoretical physics questions rather than those requiring factual knowledge. Afirst-class degree was a condition of acceptance for his planned graduate study incosmology at theUniversity of Cambridge.[64][65] Anxious, he slept poorly the night before the examinations, and the result was on the borderline between first- and second-class honours, making aviva (oral examination) with the Oxford examiners necessary.[65][66]
Hawking was concerned that he was viewed as a lazy and difficult student. So, when asked at theviva to describe his 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."[65][67] 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".[65] After receiving a first-classBA degree in physics and completing a trip toIran with a friend,[68] he began his graduate work atTrinity Hall, Cambridge, in October 1962.[28][69][70]
Post-graduate years
Hawking's first year as a doctoral student was difficult. He was initially disappointed to find that he had been assignedDennis William Sciama, one of the founders of modern cosmology, as a supervisor rather than the noted astronomerFred Hoyle,[71][72] and he found his training in mathematics inadequate for work ingeneral relativity and cosmology.[73] After being diagnosed withmotor neurone disease, Hawking fell into a depression – though his doctors advised that he continue with his studies, he felt there was little point.[74] 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 Sciama's encouragement, he returned to his work.[75][76] Hawking started developing a reputation for intelligence and brashness after a lecture in June 1964, at which he publicly challenged the work of Hoyle and his studentJayant Narlikar.[77][78]
Career
1966–1975
When Hawking began his doctoral studies, there was much debate in the physics community about the prevailing theories of the creation of theuniverse: theBig Bang andSteady State theories.[79] Inspired byRoger Penrose's theorem of aspacetimesingularity in the centre ofblack holes, Hawking applied the same thinking to the entire universe; and, during 1965, he wrote his thesis on this topic.[80][81]
Hawking's thesis was approved in 1966.[82] He also received a research fellowship atGonville and Caius College at Cambridge;[83] he obtained his PhD degree in applied mathematics and theoretical physics, specialising in general relativity and cosmology, in March 1966;[84] and his essay "Singularities and the Geometry of Space–Time" shared top honours with one by Penrose to win that year's prestigiousAdams Prize.[85][84] In 1969, Hawking accepted a specially created Fellowship for Distinction in Science to remain at Caius.[86]
Around this time, Hawking moved into the study ofquantum gravity andquantum mechanics.[105][95] This was spurred by a visit to Moscow, in which he talked withYakov Zeldovich andAlexei Starobinsky, whose work showed that, according to theuncertainty principle, rotating black holes emitparticles.[106] To Hawking's annoyance, his calculations to prove their work produced findings that contradicted his second law. It did, however, supportJacob Bekenstein's 1972 theory that black holes have an entropy proportional to thearea of the event horizon.[106][107][108] Hawking's law was nonetheless validated in 2025 by analysis of black hole mergerGW250114.[109][110]
In 1974, Hawking claimed that black holes emitradiation, known today asHawking radiation, which may continue until they exhaust their energy andevaporate.[111][112][113] Initially, Hawking radiation was controversial. Following the publication of further research, by the late 1970s, the discovery was widely accepted as a significant breakthrough in theoretical physics.[114][115][116]
Hawking was appointed to the Sherman Fairchild Distinguished Visiting Professorship at theCalifornia Institute of Technology (Caltech) in 1974.[117] He worked with a friend on the faculty,Kip Thorne,[118][6] and engaged him in ascientific wager about whether theX-ray sourceCygnus X-1 was a black hole. The wager was an "insurance policy" against the proposition that black holes did not exist.[117] Hawking acknowledged that he had lost the bet in 1990, a bet that was the first of several he was to make with Thorne and others.[119] Hawking had maintained ties to Caltech, spending a month there almost every year since this first visit.[120]
1975–1990
Hawking returned to Cambridge in 1975 to a more academically senior post, asreader in gravitational physics. The mid-to-late 1970s were a period of growing public interest in black holes and the physicists who were studying them. Hawking was regularly interviewed for print and television.[121][122] He also received increasing academic recognition of his work.[123] In 1975, he was awarded both theEddington Medal and thePius XI Gold Medal,[124] and in 1976 theDannie Heineman Prize, theMaxwell Medal and Prize, and theHughes Medal.[125][126] He was appointed a professor with a chair ingravitational physics in 1977.[127] The following year, he received theAlbert Einstein Medal and an honorary doctorate from the University of Oxford.[128][123]
In 1979, Hawking was electedLucasian Professor of Mathematics at the University of Cambridge.[123][129] His inaugural lecture in this role was titled: "Is the End in Sight for Theoretical Physics?" and proposedN = 8 supergravity as the leading theory to solve many of the outstanding problems physicists were studying.[130] His promotion coincided with a health-crisis which led to his accepting, albeit reluctantly, some nursing services at home.[131] 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.[132] In 1981, he proposed that information in a black hole is irretrievably lost when a black hole evaporates. Thisinformation paradox violates the fundamental tenet of quantum mechanics, and led to years of debate, including "the Black Hole War" withLeonard Susskind andGerard 't Hooft.[133][134]
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 byAlan Guth and also developed byAndrei Linde.[135] Following a conference in Moscow in October 1981, Hawking andGary Gibbons[6] organised a three-week Nuffield Workshop in the summer of 1982 on "The Very Early Universe" at Cambridge University, a workshop that focused mainly on inflation theory.[136][137][138] Hawking also began a new line of quantum-theory research into the origin of the universe. In 1981, at aVatican conference, he presented work suggesting that there might beno boundary – or beginning or ending – to the universe.[139][140]
Hawking subsequently developed the research in collaboration withJim Hartle,[6] and in 1983 they published a model, known as theHartle–Hawking state. It proposed that prior to thePlanck epoch, the universe had no boundary in spacetime; before the Big Bang,time did not exist and the concept of the beginning of the universe is meaningless.[141] The initial singularity of the classical Big Bang models was replaced with a region akin to theNorth 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.[142][143] Initially, the no-boundary proposal predicted a closed universe, which had implications about theexistence of God. As Hawking explained, "if the universe has no boundaries but is self-contained... thenGod would not have had any freedom to choose how the universe began."[144]
Further work by Hawking in the area ofarrows 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 andeventually collapsed,time would run backwards.[145] A paper by Don Page and independent calculations byRaymond Laflamme led Hawking to withdraw this concept.[146]
In 1982, to finance his children's education and home-expenses, Hawking decided to write a popular book about the universe that would be accessible to the general public.[147][148] Instead of publishing with an academic press, he signed a contract withBantam Books, a mass-market publisher, and received a large advance for his book.[149][150] A first draft of the book, calledA Brief History of Time, was completed in 1984.[151]
One of the first messages Hawking produced with hisspeech-generating device was a request for his assistant to help him finish writingA Brief History of Time.[152] Peter Guzzardi, his editor at Bantam, pushed him to explain his ideas clearly in non-technical language, a process that required many revisions from an increasingly irritated Hawking.[153] The book was published in April 1988 in the US and in June in the UK, and it proved to be an extraordinary success, rising quickly to the top of best-seller lists in both countries and remaining there for months.[154][155][156] The book was translated into many languages,[157] and as of 2009, has sold an estimated 9million copies.[156]
Media attention was intense,[157] and aNewsweek magazine-cover and a television special both described him as "Master of the Universe".[158] Success led to significant financial rewards, but also the challenges of celebrity status.[159] Hawking travelled extensively to promote his work, and enjoyed partying into the late hours.[157] A difficulty refusing the invitations and visitors left him limited time for work and his students.[160] Some colleagues were resentful of the attention Hawking received, feeling it was due to his disability.[161][162]
1990–2000
In 1992,Hawking conjectured thattravel into the past is effectively impossible. On 28 June 2009, as atongue-in-cheek test of the conjecture, he held a party open to all, complete with food and drinks, but publicised the party only after it was over so that only time-travellers would know to attend; as expected, nobody showed up.[163]
Hawking pursued his work in physics: in 1993, he co-edited a book onEuclidean quantum gravity with Gary Gibbons and published a collected edition of his own articles on black holes and the Big Bang.[164] In 1994, at Cambridge'sNewton Institute, Hawking and Penrose delivered a series of six lectures that were published in 1996 as "The Nature of Space and Time".[165]
In 1997, he conceded a 1991 public scientific wager made with Kip Thorne andJohn 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.[166] After discovering his concession might have been premature, a more refined wager was made, specifying that such singularities would occur without extra conditions.[167] The same year, Thorne, Hawking, and Preskill madeanother bet, this time concerning theblack hole information paradox.[168][169] Thorne and Hawking argued that since general relativity made it impossible for black holes to radiate and lose information, themass-energy and information carried by Hawking radiation must be "new", and not from inside the event horizon. Since this contradicted the quantum mechanics of microcausality,[further explanation needed] 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.[170]
Hawking also maintained his public profile, including bringing science to a wider audience. The documentaryA Brief History of Time, directed byErrol Morris, premiered in 1991; the film contains material from the book as well as interviews with Hawking, his friends, family, and colleagues. Hawking had wanted the film to be scientific rather than biographical, but he was persuaded otherwise. The film, while a critical success, was not widely released.[171] A popular-level collection of essays, interviews, and talks titledBlack Holes and Baby Universes and Other Essays was published in 1993.[172] A six-part television seriesStephen Hawking's Universe and a companion book appeared in 1997; as Hawking insisted, the focus was entirely on science.[173][174]
Hawking continued his writings for a popular audience, publishingThe Universe in a Nutshell in 2001,[175] andA Briefer History of Time, which he wrote in 2005 withLeonard Mlodinow to update his earlier works with the aim of making them accessible to a wider audience, andGod Created the Integers, which appeared in 2006.[176] Along with Thomas Hertog atCERN and Jim Hartle, from 2006 on, Hawking developed a theory oftop-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.[177] Top-down cosmology posits that the present "selects" the past from a superposition[further explanation needed] of many possible histories. In doing so, the theory suggests a possible resolution of thefine-tuning question.[178][179]
By 2003, consensus among physicists was growing that Hawking was wrong about the loss of information in a black hole.[180] 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 onetopology.[181][170] 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 such loss.[169][182] In January 2014, he called the alleged loss of information in black holes his "biggest blunder".[183] In August 2015, Hawking said that not all information is lost when something enters a black hole and there might be a possibility to retrieve information from a black hole according to his theory.[184]
Hawking in 2006
As part of another longstanding scientific dispute, Hawking had emphatically argued, and bet, that theHiggs boson would never be found.[185] The particle was proposed to exist as part of theHiggs field theory byPeter 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".[186] The particle was discovered in July 2012 at CERN following construction of theLarge Hadron Collider. Hawking quickly conceded that he had lost his bet[187][188] and said that Higgs should win theNobel Prize for Physics,[189] which he did in 2013.[190]
In 2007, Hawking and his daughterLucy publishedGeorge'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.[191] The book was followed bysequels in 2009, 2011, 2014 and 2016.[192] Hawking createdStephen Hawking: Expedition New Earth, a 2017 documentary onspace colonisation, as an episode ofTomorrow's World.[193][194]
During his career, Hawking supervised 39 successful PhD students.[1] As required by Cambridge University policy for professors who have reached the age of 67, Hawking retired as Lucasian Professor of Mathematics in 2009.[129][195] Despite suggestions that he might leave the U.K. as a protest against public funding cuts to basic scientific research,[196] Hawking worked as director of research at the Cambridge University Department of Applied Mathematics and Theoretical Physics.[197]
In his final broadcast interview, given October 2017, Hawking spoke of thescientific importance of GW170817, a black hole merger.[199] The interview was broadcast in April 2018, after his death, as theSmithsonian TV Channel documentaryLeaving Earth: Or How to Colonize a Planet.[200][201] Hawking's final paper,A smooth exit frometernal inflation?, was posthumously published in theJournal of High Energy Physics on 27 April 2018.[202][203][204] In October 2018, one of his final research studies, entitledBlack Hole Entropy and Soft Hair,[205] was published, and dealt with the "mystery of what happens to the information held by objects once they disappear into a black hole".[206][207] Also in October, Hawking's last book was published,Brief Answers to the Big Questions, containing his final comments on what he believed were the most important questions facing humankind.[208][209][210]
At Google's Zeitgeist Conference in 2011, Stephen Hawking said that "philosophy is dead". He believed that philosophers "have not kept up with modern developments in science", "have not taken science sufficiently seriously and so Philosophy is no longer relevant to knowledge claims", "their art is dead" 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".[211] His view was both praised and criticised.[212] He said, "Love, faith, and morality belong to a different category to physics. You cannot deduce how one should behave from the laws of physics. But one could hope that the logical thought that physics and mathematics involves would guide one also in one's moral behavior."[33]
Future of humanity
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."[213]
Hawking expressed concern that life on Earth is at risk from a suddennuclear war, agenetically engineered virus,global warming, anasteroid collision, or other dangers humans have not yet thought of.[214][215][208] Hawking stated: "I regard it as almost inevitable that either a nuclear confrontation or environmental catastrophe will cripple the Earth at some point in the next 1,000 years".[208] He also thought that a planet-wide disaster need not result inhuman extinction if the human race were to be able to colonise additional planets before the disaster.[215] Hawking viewed spaceflight and the colonisation of space asnecessary for the future of humanity.[214][216]
Hawking stated that, given the vastness of the universe,aliens likely exist, but that contact with them should be avoided.[217][218] He warned that aliens might pillage Earth for resources. In 2010, he said: "If aliens visit us, the outcome would be much as whenColumbus landed in America, whichdidn't turn out well for theNative Americans."[218]
Hawking warned thatsuperintelligentartificial 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."[219][220] He feared that "an extremely intelligent future AI will probablydevelop a drive to survive and acquire more resources as a step toward accomplishing whatever goal it has", and that "the real risk with AI isn't malice, but competence. A super-intelligent AI will be extremely good at accomplishing its goals, and if those goals aren'taligned with ours, we're in trouble".[221] He also considered that the enormous wealth generated by machines needs to be redistributed to prevent exacerbatedeconomic inequality.[221]
Hawking was concerned about the future emergence of a race of "superhumans" that would be able todesign their own evolution[208] and, as well, argued thatcomputer viruses in today's world should be considered a new form of life, stating that "maybe it says something abouthuman nature, that the only form of life we have created so far is purely destructive. Talk about creating life in our own image."[222]
Religion and atheism
Hawking did not rule out the existence of God, writing inA Brief History of Time: "Isthe unified theory so compelling that it brings about its own existence?",[223] also stating "If we discover a complete theory, it would be the ultimate triumph of human reason – for then we should know the mind of God";[224] in his early work, Hawking spoke of God in a metaphorical sense. In the same book, he suggested that the existence of God was notnecessary to explain the origin of the universe. Later discussions withNeil Turok led to the realisation that the existence of God was also compatible with an open universe.[225] He said: "All my work has shown is that you don't have to say that the way the universe began was the personal whim of God. But you still have the question, 'Why does the universe bother to exist?' If you like, you can define God as the answer to that question."[33]
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 realisation. 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.[229][230]
Hawking's association with atheism andfreethinking was in evidence from his university years onwards, when he had been a member of Oxford University'shumanist group. He was later scheduled to appear as the keynote speaker at a 2017Humanists UK conference.[231] In a 2014 interview, he said:
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.[226]
In addition, Hawking stated:
If you like, you can call the laws of science 'God', but it wouldn't be a personal God that you would meet and put questions to.[208]
Hawking supporteduniversal health care,[236] and maintained that without the NHS, he would not have survived into his 70s.[237] He especially fearedprivatisation of healthcare in the UK, stating: "The more profit is extracted from the system, the more privatemonopolies grow and the more expensive healthcare becomes. The NHS must be preserved from commercial interests and protected from those who want to privatise it."[238] Hawking criticized the Conservatives for wanting to privatise the NHS, and for cutting funding to it as a result.[239] He was also in favor of increasing the numbers of doctors and nurses in the NHS.[240]
Before the2014 referendum onScottish independence from the UK, Hawking was one of two hundred public figures who signed a letter endorsing a vote against independence.[241] Voters ultimately agreed with them.[242] Hawking similarly denouncedBrexit, the UK's withdrawal from theEuropean Union (EU). He predicted it would weaken the UK's contribution to global scientific efforts; he claimed modern scientific research requires international collaboration, and that freedom of movement within Europe,as is guaranteed toEU citizens, encourages the spread of ideas.[243][244] Voters decided in favor of withdrawal in a2016 referendum.[245] Later that year, as pro-Brexit Prime MinisterTheresa May honoured Hawking at thePride of Britain Awards, he told her: "please don't ask me to help with Brexit."[246]
Hawking met his future wife,Jane Wilde, at a party in 1962. The following year, Hawking was diagnosed withmotor neurone disease (MND; also known as amyotrophic lateral sclerosis (ALS) or Lou Gehrig's disease). In October 1964, the couple became engaged, while aware of Hawking's new physical limitations and shortened life expectancy.[128][253] Hawking later recalled: "Before I got motor neuron disease, I was bored with life. But the prospect of an early death made me realize life was really worth living."[33][254] The two were married on 14 July 1965 in their shared hometown of St Albans.[83]
Hawking being presented by his daughterLucy Hawking at the lecture he gave forNASA's 50th anniversary, 2008
The couple resided in Cambridge, within Hawking's walking distance to theDepartment of Applied Mathematics and Theoretical Physics (DAMTP). During their first years of marriage, Jane lived in London during the week as she completed her degree atWestfield College. They travelled to the United States several times for conferences and physics-related visits. Jane began a PhD programme through Westfield College inmedieval Spanish poetry (completed in 1981). The couple had three children: Robert, born May 1967,[255][256]Lucy, born November 1970,[257] and Timothy, born April 1979.[123]
Hawking rarely discussed his illness and physical challenges—even, in a precedent set during their courtship, with Jane.[258] His disabilities meant that the responsibilities of home and family rested firmly on his wife's shoulders, leaving him more time to think about physics.[259] Upon his appointment in 1974 to a year-long position at Caltech, Jane proposed that a graduate or post-doctoral student live with them and help with his care. Hawking accepted, andBernard Carr travelled with them as the first of many students who fulfilled this role.[260][261] The family spent a generally happy and stimulating year in Pasadena.[262]
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 doctoral thesis and her new interest in singing.[263]
Around December 1977, Jane 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 developed romantic feelings for each other.[127][264][265] According to Jane, her husband was accepting of the situation, stating "he would not object so long as I continued to love him".[127][266][267] Jane and Hellyer Jones were determined not to break up the family, and their relationship remained platonic for a long period.[268]
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.[269] The impact of his celebrity status was challenging for colleagues and family members, while the prospect of living up to a worldwide fairytale image was daunting for the couple.[270][178] Hawking's views of religion also contrasted with her strong Christian faith and resulted in tension.[178][271][272] After atracheotomy in 1985, Hawking required a full-time nurse and nursing care was split across three shifts daily. In the late 1980s, Hawking grew 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.[273] In February 1990, Hawking told Jane that he was leaving her for Mason[274] and departed the family home.[275] After his divorce from Jane in 1995, Hawking married Mason in September.[275][276]
In 1999, Jane published a memoir,Music to Move the Stars, about her marriage 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.[277] After his second marriage, Hawking's family felt excluded and marginalised from his life.[272] For a period of about five years in the early 2000s, his family and staff became increasingly worried that he was beingphysically abused.[278] Police investigations took place, but were closed as Hawking refused to make a complaint.[279]
In 2006, Hawking and Mason quietly divorced,[280][281] and Hawking resumed closer relationships with Jane, his children, and his grandchildren.[178][281] Reflecting on this happier period, a revised version of Jane's book, re-titledTravelling to Infinity: My Life with Stephen, was published in 2007,[279] and was made into a film,The Theory of Everything, in 2014.[282]
Disability
Hawking had a rare early-onset, slow-progressing form of MND, which graduallyparalysed him over decades.[21] During his final year at Oxford, he had experienced increasing clumsiness, including a fall on some stairs and difficulties when rowing.[283][284] The problems worsened, and his speech became slightlyslurred. His family noticed the changes when he returned home for Christmas, and medical investigations were begun.[285][286] He was diagnosed with MND at age 21, in 1963; doctors gave him a life expectancy of two years.[287][288]
In the late 1960s, Hawking's physical abilities declined: he began to use crutches and could no longer give lectures regularly.[289] As he slowly lost the ability to write, he developed compensatory visual methods, including seeing equations in terms of geometry.[290][291] Werner Israel later compared the achievements toMozart composing an entire symphony in his head.[292][293] Hawking was 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".[294] Jane Hawking later noted: "Some people would call it determination, some obstinacy. I've called it both at one time or another."[295] He required much persuasion to accept the use of awheelchair at the end of the 1960s,[296] but ultimately became notorious for the wildness of his wheelchair driving.[297] Hawking was popular among his colleagues, but his illness, as well as his reputation for brashness, distanced him from some.[295]
When Hawking first began using a wheelchair he was using standardmotorised models, or "powerchairs". The earliest surviving example of these chairs was made by BEC Mobility and sold byChristie's in November 2018 for £296,750.[298] Hawking continued to use this type of chair until the early 1990s, at which time his ability to use his hands to drive a wheelchair deteriorated. Hawking used a variety of different chairs from that time, including a DragonMobility Dragon elevating powerchair from 2007;[299] a Permobil C350 from 2014; and then a Permobil F3 from 2016.[300]
Hawking at anALS convention in San Francisco in the 1980s
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 interpret his speech into intelligible speech.[301] 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 improvedaccess and support for those with disabilities in Cambridge,[302][303] including adapted student housing at the university.[304] In general, Hawking had ambivalent feelings about his role as adisability rights champion: while wanting to help others, he also sought to detach himself from his illness and its challenges. His lack of engagement in this area led to some critics saying he was not doing enough, although White and Gribbin noted: "just by staying alive and continuing to work at the intense rate he and the world have grown used to, he is an inspiration to handicapped people everywhere".[305]
During a visit to CERN on the border of France and Switzerland in mid-1985, Hawking contractedpneumonia, which in his condition was life-threatening; he was so ill that Jane was asked iflife support should be terminated. She refused, but the consequence was atracheotomy, which required round-the-clock nursing care and caused the loss of what remained of his speech.[306][307] The NHS was ready to pay for anursing home, but Jane was determined that he would live at home. The cost of the care was funded by an American foundation.[308][309] 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.[310]
For his communication, Hawking initially raised his eyebrows to chooseletters on a spelling card,[311] 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 had ALS and had lost her ability to speak and write.[312] In a method he used for the rest of his life, Hawking could now simply press a switch toselect phrases, words or letters from a bank of about 2,500–3,000 that werescanned.[313][314] The program was originally run on adesktop computer. Elaine Mason's husband, David, acomputer engineer, adapted a small computer and attached it to his wheelchair.[315]
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."[316] The voice he used had an American accent and is no longer produced.[317][318] Despite the later availability of other voices, Hawking retained this original voice, saying that he preferred it and identified with it.[319] Originally, Hawking activated a switch using his hand and could produce up to15 words per minute.[152] Lectures were prepared in advance and were sent to thespeech synthesiser in short sections to be delivered.[317]
Hawking gradually lost the use of his hand, and in 2005 he began to control his communication device with movements of hischeek muscles,[320][321][322] with a rate of about one word per minute.[321] With this decline there was a risk of him developinglocked-in syndrome, so Hawking worked withIntel researchers on systems that could translate hisbrain patterns or facial expressions into switch activations. After several prototypes did not perform as planned, they settled on anadaptive word predictor made by the London-based startupSwiftKey, which used a system similar to his original technology. Hawking had an easier time adapting to the new system, which was further developed after inputting large amounts of Hawking's papers and other written materials and uses predictive software similar to other smartphone keyboards.[178][312][322][323]
Hawking in 2008
By 2009, he could no longer drive his wheelchair independently, but the same people who created his new typing mechanics were working on a method to drive his chair using movements made by his chin. This proved difficult, since Hawking could not move his neck, and trials showed that while he could indeed drive the chair, the movement was sporadic and jumpy.[312][324] Near the end of his life, Hawking experienced increased breathing difficulties, often resulting in his requiring the usage of aventilator, and being regularly hospitalised.[178]
Hawking continued to travel widely, including trips to Chile,Easter Island, South Africa, Spain (to receive theFonseca Prize in 2008),[325][326] Canada,[327] and numerous trips to the U.S.[328] 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.[329]
Disability outreach
Starting in the 1990s, Hawking accepted the mantle of role model for disabled people, lecturing and participating in fundraising activities.[330] At the turn of the century, he and eleven other humanitarians signed theCharter for the Third Millennium on Disability, which called on governments to prevent disability and protect the rights of disabled people.[331][332] In 1999, Hawking was awarded theJulius Edgar Lilienfeld Prize of theAmerican Physical Society.[333]
In August 2012, Hawking narrated part of theopening ceremony of the2012 Summer Paralympics in London.[334] In September 2013, he expressed support for the legalisation ofassisted suicide for the terminally ill.[335] In August 2014, Hawking was given theIce Bucket Challenge—in which someone pours a bucket of ice water over their head on video, before challenging someone else—to promote ALS/MND awareness and research funding; as he had pneumonia in 2013, he did not have ice poured over him, but his children accepted the challenge on his behalf.[336]
In late 2006, Hawking stated that one of his greatest unfulfilled desires was to travel to space.[337] On hearing this,Richard Branson offered a free flight into space withVirgin Galactic, which Hawking immediately accepted. Besides personal ambition, he was motivated by the desire to increase public interest inspaceflight and to show the potential of people with disabilities.[214] On 26 April 2007, Hawking flew aboard aspecially-modifiedBoeing 727-200 jet operated byZero-G Corp off the coast of Florida to experience weightlessness.[338] Fears that the manoeuvres would cause him undue discomfort proved incorrect, and the flight was extended to eightparabolic arcs.[337] It was described as a successful test to see if he could withstand theg-forces involved in spaceflight.[339] At the time, the date of Hawking's trip to space was projected to be as early as 2009, butcommercial flights to space did not commence before his death.[340]
Hawking was mentioned in court documents released in 2024 during the trial ofGhislaine Maxwell, a Britishchild sex trafficker who conspired with American financierJeffrey Epstein (whodied in 2019[341]). The documents included an email Epstein sent in 2015, asking friends of Epstein's alleged victim,Virginia Giuffre, to disprove supposed allegations of Giuffre's that Hawking participated in an "underageorgy" in theU.S. Virgin Islands, whereEpstein lived. Epstein said he "can issue a reward” to them if they can "prove her allegations are false". The email implies it was written in response to a "new version" of the claim regarding Hawking. Neither Giuffre (who died in 2025[342]) nor anyone else has ever publicly accused Hawking of sexual misconduct.[343][344][345] According to physicistLisa Randall—who was found in 2026 to have corresponded with Epstein—in 2006, Hawking and Epstein were both present at a conference on gravity. Randall describes both her correspondence and Epstein's appearance at the conference as resulting from Epstein's public financing of scientific efforts.[346]
Inscribed on his memorial stone are the words: "Here lies what was mortal of Stephen Hawking 1942–2018" and his most famed equation, theBekenstein–Hawking formula, used in discussing entropy inblack hole thermodynamics:[367][c]He directed that the equation be hisepitaph at least fifteen years before his death.[370][373]
In June 2018, it was announced that a speech of Hawking's, set to music by Greek composerVangelis, would be beamed into space from aEuropean Space Agencysatellite dish in Spain in the direction of the nearest black hole,1A 0620-00.[374]
On 8 November 2018, an auction of 22 personal possessions of Hawking, including his doctoral thesis (Properties of Expanding Universes, PhD thesis, Cambridge University, 1965) and wheelchair, took place, and fetched about £1.8 million.[375][376] Proceeds from the auction sale of the wheelchair went to two charities, theMotor Neurone Disease Association and the Stephen Hawking Foundation;[377] proceeds from the other items went to his estate.[376]
In March 2019, it was announced that theRoyal Mint would issue a commemorative50p coin, only available as a commemorative edition,[378] in honour of Hawking.[379] The same month, Hawking's nurse, Patricia Dowdy, was struck off the nursing register for "failures over his care and financial misconduct".[380]
In May 2021, it was announced that an Acceptance-in-Lieu agreement between HMRC, the Department for Culture, Media and Sport, Cambridge University Library, Science Museum Group, and the Hawking Estate, would see around 10,000 pages of Hawking's scientific and other papers remain in Cambridge, while objects including his wheelchairs, speech synthesisers, and personal memorabilia from his former Cambridge office would be housed at the Science Museum.[381] In February 2022, the "Stephen Hawking at Work" display opened at theScience Museum, London as the start of a two-year nationwide tour.[382] In October 2024, the Hawking Building was opened to the public at theScience and Innovation Park as a new facility to house the Science Museum's National Collection Centre which includes about 80% of the museum's object collection.[383]
Hawking appeared in multiple documentary films, includingGod, the Universe and Everything Else (1988),[384]The Real Stephen Hawking (2001),[332]Stephen Hawking: Profile (2002),[385] andHawking (2013),[386] and the documentary seriesStephen Hawking, Master of the Universe (2008).[387]
In 2022, Google featured Hawking in aGoogle Doodle on the occasion of his 80th birthday.[403]
Awards and honours
Hawking received numerous awards and honours. Already early in the list, in 1974 he was elected a Fellow of theRoyal Society (FRS).[6] 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."[404]
Hawking received the 2015BBVA Foundation Frontiers of Knowledge Award in Basic Sciences shared withViatcheslav Mukhanov for discovering that the galaxies were formed from quantum fluctuations in the early Universe. At the 2016Pride of Britain Awards, Hawking received the lifetime achievement award "for his contribution to science and British culture".[428] After receiving the award from Theresa May, Hawking humorously requested that she not seek his help with Brexit.[428]
In 2017, theCambridge Union Society, in conjunction with Hawking, established theProfessor Stephen Hawking Fellowship. The fellowship is awarded annually to an individual who has made an exceptional contribution to theSTEM fields and social discourse,[429] with a particular focus on impacts affecting the younger generations. Each fellow delivers a lecture on a topic of their choosing, known as the "Hawking Lecture".[430]
Hawking himself accepted the inaugural fellowship, and he delivered the first Hawking Lecture in his last public appearance before his death.[431][432]
Hawking was a member of the advisory board of theStarmus Festival, and had a major role in acknowledging and promoting science communication. TheStephen Hawking Medal for Science Communication is an annual award initiated in 2016 to honour members of the arts community for contributions that help build awareness of science.[433] Recipients receive a medal bearing a portrait of Hawking byAlexei Leonov, and the other side represents an image of Leonov himself performing thefirst spacewalk along with an image of the "Red Special", the guitar of Brian May (with music being another major component of the Starmus Festival).[434]
TheStarmus III Festival in 2016 was a tribute to Stephen Hawking and the book of all Starmus III lectures, "Beyond the Horizon", was also dedicated to him. The first recipients of the medals, which were awarded at the festival, were chosen by Hawking himself: composerHans Zimmer, physicistJim Al-Khalili, and the science documentary filmParticle Fever (2013).[435]
where the subscript BH stands for either "black hole" or "Bekenstein–Hawking". This can be expressed more simply as a proportionality between twodimensionless ratios:
where is thePlanck length.Jacob Bekenstein had conjectured the proportionality; Hawking confirmed it and established the constant of proportionality at.[26][112] Calculations based onstring theory, first carried out in 1995, have been found to yield the same result.[372]This relationship is conjectured to be valid not just for black holes, but also (sinceentropy is proportional to information) as anupper bound on the amount of information that can be contained in any volume of space, which has in turn spawned deeper reflections on the possiblenature of reality.
^Galfard, Christophe Georges Gunnar Sven (2006).Black hole information & branes (PhD thesis). University of Cambridge.Archived from the original on 25 January 2016. Retrieved5 February 2014.
^See Guth (1997) for a popular description of the workshop, orThe Very Early Universe,ISBN0-521-31677-4 eds Gibbons, Hawking & Siklos for a detailed report.
^Hawking, S.W.; Thorne, K.S.; Preskill (6 February 1997)."Black hole information bet". Pasadena, California.Archived from the original on 11 May 2013. Retrieved20 April 2013.
^Castle, Stephen (15 June 2018)."Stephen Hawking Enters 'Britain's Valhalla,' Where Space Is Tight".The New York Times.Archived from the original on 2 January 2019. Retrieved21 July 2019.when Stephen Hawking's ashes were interred there on Friday, they were placed between the remains of Isaac Newton and Charles Darwin
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