Stephen William Hawking (8 January 1942 – 14
March 2018) was an English theoretical physicist,
cosmologist, and author, who was director
of research at the Centre for Theoretical
Cosmology at the University of Cambridge at
the time of his death.
He was the Lucasian Professor of Mathematics
at the University of Cambridge between 1979
and 2009.
His scientific works included 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 out a theory
of cosmology explained by a union of the general
theory of relativity and quantum mechanics.
He was a vigorous supporter of the many-worlds
interpretation of quantum mechanics.Hawking
achieved commercial success with several 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 was a fellow of the Royal Society
(FRS), a lifetime member of the Pontifical
Academy of Sciences, and a recipient of the
Presidential Medal of Freedom, the highest
civilian award in the United States.
In 2002, Hawking was ranked number 25 in the
BBC's poll of the 100 Greatest Britons.
Hawking had a rare early-onset slow-progressing
form of motor neurone disease (also known
as amyotrophic lateral sclerosis "ALS" or
Lou Gehrig's disease) that gradually paralysed
him over the decades.
Even after the loss of his speech, he was
still able to communicate through a speech-generating
device, initially through use of a hand-held
switch, and eventually by using a single cheek
muscle.
He died on 14 March 2018 at the age of 76.
== Early life ==
=== Family ===
Hawking was born on 8 January 1942 in Oxford
to Frank (1905–1986) and Isobel Eileen Hawking
(née Walker; 1915–2013).
Hawking's mother was born into a family of
doctors in Glasgow, Scotland.
His wealthy paternal great-grandfather, from
Yorkshire, had over-extended himself buying
farm land and then going bankrupt in the great
agricultural depression during the early 20th
century.
His paternal great-grandmother saved the family
from financial ruin by opening a school in
their home.
Despite their families' financial constraints,
both parents attended the University of Oxford,
where Frank read medicine and Isobel read
Philosophy, Politics and Economics.
Isobel worked as a secretary for a medical
research institute, and Frank was a medical
researcher.
Hawking had two younger sisters, Philippa
and Mary, and an adopted brother, Edward Frank
David (1955–2003).In 1950, when Hawking's
father became head of the division of parasitology
at the National Institute for Medical Research,
the family moved to St Albans, Hertfordshire.
In St Albans, the family was 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.
=== Primary and secondary school years ===
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 two independent
(i.e. fee-paying) schools, first Radlett School
and from September 1952, St Albans School,
after passing the eleven-plus a year early.
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 known
at school 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 also wanted his son 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.
=== Undergraduate years ===
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 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 of an 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 crew.
The rowing coach at the time noted that Hawking
cultivated a daredevil image, steering his
crew on risky courses that led to damaged
boats.Hawking estimated that he studied about
1,000 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
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 physics and completing a trip to Iran with
a friend, he began his graduate work at Trinity
Hall, Cambridge, in October 1962.
=== Graduate years ===
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 Yorkshire 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.
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.
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 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.
Hawking's thesis was approved in 1966.
There were other positive developments: Hawking
received a research fellowship at Gonville
and Caius College at Cambridge; he obtained
his PhD degree in applied mathematics and
theoretical physics, specialising in general
relativity and cosmology, in March 1966; and
his essay "Singularities and the Geometry
of Space-Time" shared top honours with one
by Penrose to win that year's prestigious
Adams Prize.
== Career ==
=== 1966–1975 ===
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, one that
states 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.
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 X-ray source 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, a bet that was the first of several
he was to make with Thorne and others.
Hawking had maintained ties to Caltech, spending
a month there almost every year since this
first visit.
=== 1975–1990 ===
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 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 1979, Hawking
was elected Lucasian Professor of Mathematics
at the University of Cambridge.
His inaugural lecture in this role 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 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.
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 that the existence
of God was not necessary to explain the origin
of the universe.
Later discussions with Neil Turok led to the
realisation that the existence of God was
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 the 1982 New Year Honours appointed a Commander
of the Order of the British Empire (CBE).
These awards did not significantly change
Hawking's financial status, and motivated
by the need to finance his children's education
and home expenses, he decided in 1982 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 many revisions
from an increasingly irritated Hawking.
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.
The book was translated into many languages,
and ultimately sold an estimated 9 million
copies.
Media attention was intense, and a 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.
A difficulty refusing the invitations and
visitors left him 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 more 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 the 1989 Birthday Honours, he was appointed
a Companion of Honour (CH).
He reportedly declined a knighthood in the
late 1990s in objection to the UK's science
funding policy.
=== 1990–2000 ===
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 that 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 and more refined wager
was made.
This one 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 not
widely released.
A popular-level collection of essays, interviews,
and talks titled Black Holes and Baby Universes
and Other Essays was published in 1993, and
a six-part television series Stephen Hawking's
Universe and a companion book appeared in
1997.
As Hawking insisted, this time the focus was
entirely on science.
=== 2000–2018 ===
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 with the aim of making
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 numerous 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 such loss.
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, 2014 and 2016.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 the 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 supervised 39 successful
PhD students.
One doctoral student did not successfully
complete the PhD.
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 worked as director of research at
the Cambridge University Department of Applied
Mathematics and Theoretical Physics.On 28
June 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 publicised the party
only 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.
Hawking created Stephen Hawking: Expedition
New Earth, a documentary on space colonisation,
as a 2017 episode of Tomorrow's World.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.
In July 2017, Hawking was awarded an Honorary
Doctorate from Imperial College London.Hawking's
final paper – A smooth exit from eternal
inflation? – was published in the Journal
of High Energy Physics on 27 April 2018.
== Personal life ==
=== Marriages ===
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 late 1963 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 his 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.
=== Disability ===
Hawking had a rare early-onset slow-progressing
form of motor neurone disease (also known
as amyotrophic lateral sclerosis, "ALS", or
Lou Gehrig's disease), that 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 and 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 could no longer give lectures
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 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: "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 interpret 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, Hawking had ambivalent feelings
about his role as a disability 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 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 required round-the-clock nursing care
and the removal of what remained of his speech.
The National Health Service was ready to 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 used for the rest of his life,
Hawking could now simply press a switch to
select phrases, words or letters from a bank
of about 2,500–3,000 that were scanned.
The program was originally run on a desktop
computer.
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 used had an American accent and
is no longer produced.
Despite the later availability of other voices,
Hawking retained this original voice, saying
that he preferred it and identified with it.
Originally, 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 synthesizer 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 was 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 settled on an adaptive word
predictor made by the London-based startup
SwiftKey, 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.
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.
Near the end of his life, Hawking experienced
increased breathing difficulties, often resulting
in his requiring the usage of a ventilator,
and being regularly hospitalised.
=== Disability outreach ===
Starting in the 1990s, Hawking 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
the rights of the disabled.
In 1999, Hawking was awarded the Julius Edgar
Lilienfeld Prize of the American Physical
Society.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.
=== Plans for a trip to space ===
In late 2006, Hawking revealed in a BBC interview
that one of his greatest unfulfilled desires
was to travel to space; on hearing this, Richard
Branson offered a free flight into space with
Virgin Galactic, which Hawking immediately
accepted.
Besides personal ambition, he was motivated
by the desire to increase public interest
in spaceflight and to show the potential of
people with disabilities.
On 26 April 2007, Hawking flew aboard a specially-modified
Boeing 727–200 jet operated by Zero-G Corp
off the coast of Florida to experience weightlessness.
Fears the manoeuvres would cause him undue
discomfort proved groundless, and the flight
was extended to eight parabolic arcs.
It was described as a successful test to see
if he could withstand the g-forces involved
in space flight.
At the time, the date of Hawking's trip to
space was projected to be as early as 2009,
but commercial flights to space did not commence
before his death.
== Death ==
Hawking died at his home in Cambridge, England,
early in the morning of 14 March 2018, at
the age of 76.
His family stated that he "died peacefully".
He was eulogised by figures in science, entertainment,
politics, and other areas.
The Gonville and Caius College flag flew at
half-mast and a book of condolences was signed
by students and visitors.
A tribute was made to Hawking in the closing
speech by IPC President Andrew Parsons at
the closing ceremony of the 2018 Paralympic
Winter Games in Pyeongchang, South Korea.Hawking's
final broadcast interview, about the detection
of gravitational waves resulting from the
collision of two neutron stars, occurred in
October 2017.
His final words to the world appeared posthumously,
in April 2018, in the form of a Smithsonian
TV Channel documentary entitled, Leaving Earth:
Or How to Colonize a Planet.
One of his final research studies, entitled
A smooth exit from eternal inflation?, about
the origin of the universe, was published
in the Journal of High Energy Physics in May
2018.
Later, in October 2018, another of his final
research studies, entitled Black Hole Entropy
and Soft Hair, was published, and dealt with
the "mystery of what happens to the information
held by objects once they disappear into a
black hole".
Also in October 2018, Hawking's last book,
Brief Answers to the Big Questions, a popular
science book presenting his final comments
on the most important questions facing humankind,
was published.Hawking was born on the 300th
anniversary of Galileo's death and died on
the 139th anniversary of Einstein's birth.
His private funeral took place at 2 pm on
the afternoon of 31 March 2018, at Great St
Mary's Church, Cambridge.
Guests at the funeral included Eddie Redmayne,
Felicity Jones, and Queen guitarist and astrophysicist
Brian May.
Following the cremation, a service of thanksgiving
was held at Westminster Abbey on 15 June 2018,
after which his ashes were interred in the
Abbey's nave, alongside the grave of Sir Isaac
Newton and close to that of Charles Darwin.During
the service, readings and tributes were made
by Benedict Cumberbatch, who played Hawking
in a BBC television film, astronaut Tim Peake,
Astronomer Royal Martin Rees, and Nobel Prize
winner Kip Thorne.
Inscribed on his memorial stone are the words
"Here lies what was mortal of Stephen Hawking
1942 - 2018" and his most famed equation.
He directed, at least fifteen years before
his death, that the Bekenstein–Hawking entropy
equation be his epitaph. in June 2018, it
was announced that Hawking's words, set to
music by Greek composer Vangelis, are to be
beamed into space from a European space agency
satellite dish in Spain with the aim of reaching
the nearest black hole, 1A 0620-00.On 8 November
2018, an auction of 22 personal possessions
of Stephen Hawking, including his doctoral
thesis ("Properties of Expanding Universes",
Ph.D. thesis, Cambridge University, 1965)
and wheelchair, took place, and fetched about
£1.8m (more than $2.3m).
Proceeds from the auction sale of the wheelchair
are to go to two charities, the Motor Neurone
Disease Association and the Stephen Hawking
Foundation,; proceeds from Hawking's other
items are to go to his estate.
== Personal views ==
=== 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."Hawking expressed concern
that life on Earth is at risk from a sudden
nuclear war, a genetically engineered virus,
global warming, or other dangers humans have
not yet thought of.
Hawking has 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”, and has considered an "asteroid
collision" to be the biggest threat to the
planet.
Such a planet-wide disaster need not result
in human extinction if the human race were
to be able to colonise additional planets
before the disaster.
Hawking viewed spaceflight and the colonisation
of space as necessary for the future of humanity.Hawking
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 warned that
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."
However, he argued that we should be more
frightened of capitalism exacerbating economic
inequality than robots.Hawking was concerned
about the future emergence of a race of “superhumans”
that would be able to design their own evolution
and, as well, argued that computer viruses
in today's world should be considered a new
form of life, stating 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."
=== Science vs. philosophy ===
At Google's Zeitgeist Conference in 2011,
Hawking said that "philosophy is dead".
He believed 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".
=== Religion and atheism ===
Hawking was an atheist and believed that "the
universe is governed by the laws of science".
He 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."
In an interview published in The Guardian,
Hawking regarded "the brain as a computer
which will stop working when its components
fail", and the concept of an afterlife as
a "fairy story for people afraid of the dark".
In 2011, 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 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.
In September 2014, he joined the Starmus Festival
as keynote speaker and declared himself an
atheist.
In an interview with El Mundo, 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.
In addition, Hawking has 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.
=== Politics ===
Hawking was 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", supported
the academic boycott of Israel, campaigned
for nuclear disarmament, and supported stem
cell research, universal health care, and
action to prevent climate change.
In August 2014, Hawking was one of 200 public
figures who were signatories to a letter to
The Guardian expressing their hope that Scotland
would vote to remain part of the United Kingdom
in September's referendum on that issue.
Hawking believed a United Kingdom withdrawal
from the European Union (Brexit) would 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 was disappointed by Brexit and warned
against envy and isolationism.Hawking was
greatly concerned over health care, and maintained
that without the UK National Health Service,
he could not have survived into his 70s.
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."Hawking feared
privatisation.
He stated, "The more profit is extracted from
the system, the more private monopolies grow
and the more expensive healthcare becomes.
The NHS must be preserved from commercial
interests and protected from those who want
to privatise it."
Hawking alleged ministers damaged the NHS,
he blamed the Conservatives for cutting funding,
weakening the NHS by privatisation, lowering
staff morale through holding pay back and
reducing social care.
Hawking accused Jeremy Hunt of cherry picking
evidence which Hawking maintained debased
science.
Hawking also stated, "There is overwhelming
evidence that NHS funding and the numbers
of doctors and nurses are inadequate, and
it is getting worse."In June 2017, Hawking
endorsed the Labour Party in the 2017 UK general
election, citing the Conservatives' proposed
cuts to the NHS.
But he was also critical of Labour leader
Jeremy Corbyn, expressing scepticism over
whether the party could win a general election
under him.Hawking feared Donald Trump's policies
on global warming could endanger the planet
and make global warming irreversible.
He said, "Climate change is one of the great
dangers we face, and it's one we can prevent
if we act now.
By denying the evidence for climate change,
and pulling out of the Paris Agreement, Donald
Trump will cause avoidable environmental damage
to our beautiful planet, endangering the natural
world, for us and our children."
Hawking further stated that this could lead
Earth "to become like Venus, with a temperature
of two hundred and fifty degrees, and raining
sulphuric acid".
== Appearances in popular media ==
In 1988, Stephen Hawking, Arthur C. Clarke
and Carl Sagan were interviewed in God, the
Universe and Everything Else.
They discussed the Big Bang theory, God and
the possibility of extraterrestrial life.
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 synthesizer voice was recorded
for the Pink Floyd song "Keep Talking", and
in 1999 for an appearance on The Simpsons.
Hawking appeared in documentaries titled The
Real Stephen Hawking (2001), Stephen Hawking:
Profile (2002) and Hawking (2013), and the
documentary series Stephen Hawking, Master
of the Universe (2008).
Hawking 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 used his fame to advertise products,
including a wheelchair, National Savings,
British Telecom, Specsavers, Egg Banking,
and Go Compare.
In 2015 he applied to trademark his name.Broadcast
in March 2018 just a week or two before his
death, Hawking was the voice of The Book Mark
II on The Hitchhiker's Guide to the Galaxy
radio series, and he was the guest of Neil
deGrasse Tyson on StarTalk.
== Awards and honours ==
Hawking 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".
After receiving the award from Prime Minister
Theresa May, Hawking humorously requested
that she not seek his help with Brexit.
=== Stephen Hawking Medal for Science Communication
===
Hawking was a member of the Advisory Board
of the Starmus Festival, and had a major role
in acknowledging and promoting science communication.
The Stephen 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.
Recipients receive a medal bearing a portrait
of Stephen Hawking by Alexei Leonov, and the
other side represents an image of Leonov himself
performing his famous space walk and the iconic
"Red Special", Brian May's guitar.The Starmus
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.
They were composer Hans Zimmer, physicist
Jim Al-Khalili, and the science documentary
Particle Fever.
=== Black Hole discovery dedication ===
In March 2018, it was announced that two Russian
astronomers who discovered GRB180316A, a newborn
black hole in the Ophiuchus constellation
on 16 March 2018, had dedicated their find
to Stephen Hawking, having discovered it two
days after his death.
== Publications ==
=== Popular books ===
A Brief History of Time (1988)
Black Holes and Baby Universes and Other Essays
(1993)
The Universe in a Nutshell (2001)
On the Shoulders of Giants (2002)
God Created the Integers: The Mathematical
Breakthroughs That Changed History (2005)
The Dreams That Stuff Is Made of: The Most
Astounding Papers of Quantum Physics and How
They Shook the Scientific World (2011)
My Brief History (2013)
Brief Answers to the Big Questions (2018)
==== Co-authored ====
The Nature of Space and Time (with Roger Penrose)
(1996)
The Large, the Small and the Human Mind (with
Roger Penrose, Abner Shimony and Nancy Cartwright)
(1997)
The Future of Spacetime (with Kip Thorne,
Igor Novikov, Timothy Ferris and introduction
by Alan Lightman, Richard H. Price) (2002)
A Briefer History of Time (with Leonard Mlodinow)
(2005)
The Grand Design (with Leonard Mlodinow) (2010)
==== Forewords ====
Black Holes & Time Warps: Einstein's Outrageous
Legacy (Kip Thorne, and introduction by Frederick
Seitz) (1994)
=== Children's fiction ===
Co-written with his daughter Lucy.
George's Secret Key to the Universe (2007)
George's Cosmic Treasure Hunt (2009)
George and the Big Bang (2011)
George and the Unbreakable Code (2014)
George and the Blue Moon (2016)
=== Films and series ===
A Brief History of Time (1992)
Stephen Hawking's Universe (1997)
Hawking – BBC television film (2004) starring
Benedict Cumberbatch
Horizon: The Hawking Paradox (2005)
Masters of Science Fiction (2007)
Stephen Hawking and the Theory of Everything
(2007)
Stephen Hawking: Master of the Universe (2008)
Into the Universe with Stephen Hawking (2010)
Brave New World with Stephen Hawking (2011)
Stephen Hawking's Grand Design (2012)
The Big Bang Theory (2012, 2014–2015, 2017)
Stephen Hawking: A Brief History of Mine (2013)
The Theory of Everything – Feature film
(2014) starring Eddie Redmayne
Genius by Stephen Hawking (2016)
=== Selected academic works ===
Hawking, S.W.; Penrose, R. (1970).
"The Singularities of Gravitational Collapse
and Cosmology".
Proceedings of the Royal Society A: Mathematical,
Physical and Engineering Sciences.
314 (1519): 529–548.
Bibcode:1970RSPSA.314..529H. doi:10.1098/rspa.1970.0021.
Hawking, S. (1971).
"Gravitational Radiation from Colliding Black
Holes".
Physical Review Letters.
26 (21): 1344–1346.
Bibcode:1971PhRvL..26.1344H. doi:10.1103/PhysRevLett.26.1344.
Hawking, S.W. (1972).
"Black holes in general relativity".
Communications in Mathematical Physics.
25 (2): 152–166.
Bibcode:1972CMaPh..25..152H. doi:10.1007/BF01877517.
Archived from the original on 13 January 2012.
Hawking, S.W. (1974).
"Black hole explosions?".
Nature.
248 (5443): 30–31.
Bibcode:1974Natur.248...30H. doi:10.1038/248030a0.
Hawking, S.W. (1982).
"The development of irregularities in a single
bubble inflationary universe".
Physics Letters B. 115 (4): 295–297.
Bibcode:1982PhLB..115..295H. doi:10.1016/0370-2693(82)90373-2.
Hartle, J.; Hawking, S. (1983).
"Wave function of the Universe".
Physical Review 
D. 28 (12): 2960–2975.
Bibcode:1983PhRvD..28.2960H. doi:10.1103/PhysRevD.28.2960.
Hawking, S.W. (1996).
"The Gravitational Hamiltonian in the Presence
of Non-Orthogonal Boundaries".
Classical 
and Quantum Gravity.
13 (10): 2735–2752.
arXiv:gr-qc/9603050.
Bibcode:1996CQGra..13.2735H. CiteSeerX 10.1.1.339.8756.
doi:10.1088/0264-9381/13/10/012.
Hawking, S. (2005).
"Information loss in black holes".
Physical Review D. 72 (8): 084013.
arXiv:hep-th/0507171.
Bibcode:2005PhRvD..72h4013H.
doi:10.1103/PhysRevD.72.084013.
Hawking, S.; Hertog, T. (2018).
"A smooth exit from eternal inflation?".
Journal of High Energy Physics.
147 (4).
arXiv:1707.07702.
Bibcode:2018JHEP...04..147H. doi:10.1007/JHEP04(2018)147.
== Notes ==
== References ==
=== Sources ===
== External links ==
Official website
Stephen Hawking on Facebook
Stephen Hawking on IMDb
Stephen Hawking at the Internet Speculative
Fiction Database
Portraits of Stephen William Hawking at the
National Portrait Gallery, London
"Archival material relating to Stephen Hawking".
UK National Archives.
"Stephen Hawking collected news and commentary".
The New York Times.
Stephen Hawking's publications indexed by
the Scopus bibliographic database.
(subscription required)
Stephen Hawking at Encyclopædia Britannica
Appearances on C-SPAN
Works by or about Stephen Hawking in libraries
(WorldCat catalog)
"Stephen Hawking collected news and commentary".
The Guardian.
Stephen Hawking at TED
"Stephen Hawking at 70: Exclusive interview".
New Scientist.
4 January 2012.
The Universe and Beyond, with Stephen Hawking
StarTalk video
Stephen Hawking’s Black Hole Theory (video;
08:39; 16 October 2018) on YouTube (text)
