[ Music ]
[ Applause ]
>> Hello everyone.
What a wonderful evening we've
got prepared for you today.
Have you ever wondered how
the universe came to exist
or how it will end, whether
or not we are alone
in the universe?
And what is the place
of human beings
in the great cosmic
scheme of things?
Well, I wonder about questions
like that all the time
but then I'm paid to do so.
I'm sure everyone out there
from time to time has grappled
with these great
questions of existence.
But for most of human history,
they've been confined largely
to the realms of
philosophy and religion.
Over the last few
decades, however,
science has increasingly
made contributions
so that these questions, which
people have asked for centuries
and centuries, may now be on
the verge of being answered.
One of the people
most responsible
for the transformation
in our understanding
of how the world works is the
man we have come to listen
to tonight, Stephen Hawking.
Dazzling advances in
astronomy and improvements
in our understanding
of the world using
theoretical physics have led
to these tremendous developments
that are so exciting
in which we are proud to
bring to you this evening.
This year, we celebrate
the centenary of one
of mankind's greatest
intellectual achievements,
Albert Einstein's general
theory of relativity.
Amid the chaos of the
First World War, indeed,
in the closing days of
the Gallipoli campaign,
Einstein presented his now
legendary field equations
of gravitation.
And in this theory, Einstein
described gravitation not
as Newton had over two centuries
before in terms of a force
of attraction operating across
empty space, but instead,
in terms of a warping
or distortion
in the geometry of
space and time.
In the beginning,
only tiny directions
to Newton's theory
could be observed.
So Einstein's theory
soon came to be accepted
but it was relegated
to backwater of physics
because the effects
were so small.
Its most significant
accomplishment was explaining
why the universe is expanding,
why all the galaxies
are flying apart
from all the other galaxies,
something that was discovered
by Edwin Hubble and
others in the 1920's.
But the subject of cosmology, in
general, and the term big bang
in particular still lay
decades in the future.
It was only in the 1960's
that gravitation theory
finally enjoyed a renaissance.
The renewed interest
was triggered in part
by the discovery of
weird objects in space
like quasars and pulsars.
These objects had such
enormous gravitational fields
that they could not
be understood
without invoking Einstein's
general theory of relativity.
Now this theory had, by that
stage, become notoriously hard
to understand and
mathematically very challenging.
Only a handful of
exact solutions
to Einstein's field
equations were known.
Well, my wife had a
comment last night.
She said, "I don't
understand this.
You have an equation
and it has a solution
and you either know
it or you don't.
What's the problem?"
If only it were that simple.
In the 1960's also,
there were developments
in mathematical techniques
that enabled Einstein's
general theory of relativity
in this warping and the
geometry of space and time
to be understood much better.
There have been a lot of
confusion about the subject
and over the interpretation
of what these curved
geometries meant.
And this was especially
successful when applied
to what we now call black holes.
And it was into this revitalised
world of gravitational theory
that the young Stephen
Hawking stepped.
I've known Stephen since 1970
when I was a post doctoral
fellow at the Institute
of Theoretical Astronomy
in Cambridge
and Stephen was the
man in the wheelchair
in a neighbouring office.
In those days, he was not yet a
celebrity but I've read a couple
of his papers and a colleague
remarked soon after I arrived,
"Never ignore anything
that Stephen Hawking does,"
and that turned out to
be very sound advice.
I have endearing memories
of Stephen propelling himself
backward down the corridor
like this in the days when
he didn't have a motorised
wheelchair, it was
a manual wheelchair.
Where was he going?
He was heading for the library
and it was in the library we use
to take our tea break, which as
you know is a crucial tradition
in British life generally, in
academic life in particular.
Because it was over
tea that people learnt
about each other's theories
and ideas, swap gossip
and generally, have a good time.
And it was in these
informal tea breaks
that I discovered Stephen's
mischievous sense of humour
and his dogged persistence
of conferences and meetings
around the world that
would often be tours
and sight seeing
trips, visits to bars
and restaurants and so fort.
Stephen would always
insist on coming along.
I had many memories.
For example, carrying him
up a very steep flight
of concrete steps next to a
particle accelerator in Canada
so that he could take
a look at this view
of this enormous machine,
carrying him in the wheelchair
and I hesitate to--
it was not just me.
It took four of us to
lift him up off the ground
and there were many
instances like that.
There was another that
I remember of going--
in [inaudible] of going down
to the pub on the quayside
on a freezing day,
none of us with coats,
Stephen cheerfully coming along
to have a beer with
the rest of us.
Well, in spite of the
success of Einstein's theory,
many physicists felt it
was somehow incomplete
because it was hard to merge
with that other great product
of 20th century physics,
which is quantum mechanics.
It was Stephen's visionary
application of quantum mechanics
to black holes in the mid 1970's
that founded an entire new field
of theoretical physics.
But I'll leave it to Stephen
to explain that himself.
Over the intervening years, not
any astronomy but cosmology,
and I should say that cosmology
is the study of the universe
as a whole, its origin,
evolution, and ultimate faith.
That these subjects
advance in leaps and bounds.
Cosmologists agree that the
universe began with the big bang
but they squabble over what if
anything happened before it.
Was the big bang
the ultimate origin
of all physical things
including space and time,
or is our universe just
an infinitesimal fragment
in a vast more elaborate
assemblage of universes
with big bangs going off like
this scattered throughout space
and time and some
eternal overall system.
Well, back in the 1970's,
many people thought
that although physics
could be applied
to the first split second of
the universe after the big bang,
the origin itself, the
first event was off limits
that you couldn't
apply science to that.
But Stephen felt otherwise,
and in a bold proposal
that he's going to
tell you about,
he demonstrated mathematically
how quantum mechanics might
bring the very origin of the
universe within the scope
of scientific enquiry.
Well enough of science,
Stephen is of course well known
to many people around
the world as an author.
Indeed, one of the best
selling authors of all time.
With his book "A Brief
History of Time" he was able
to reach parts of
the reading public
that few other scientists
could hope to attract.
Those of us who struggled
to compete again,
measuring our book sales
in millihawkins [phonetic].
[ Laughter ]
Since then, Stephen has
extended his literary reach
in partnership with his daughter
Lucy to include everyone
from the age of 8 to 80.
And I really do hope that
there are some people out there
at the age of 8, if
there's an 8-year-old
in the audience say "hello."
>> Hello.
>> Ahh.
[ Laughter ]
[ Applause ]
Well, a special welcome.
The recent film theory of
everything, which we're going
to chat about later, helps
convey the human side
of Stephen's remarkable life.
The books and films are no
substitute for the real person
and tonight, we're thrilled
to be able to come as close
as the laws of physics permit
to bring Stephen Hawking to you
in this world famous
Opera House.
And here, to introduce Stephen
is someone who's known him all
her life, Lucy Hawking.
Lucy is a writer with
a remarkable skill
for communicating
science to everyone
but especially to the children.
Ladies and gentlemen,
please welcome Lucy Hawking.
[ Applause ]
>> Thank you Paul [inaudible].
[ Applause ]
Good evening ladies
and gentlemen.
In a few short minutes,
you're going to see my father,
Stephen Hawking, appear as
a hologram from his home
in Cambridge, England.
And it's my pleasure to be here
with you in person this evening
to introduce you to
my virtual father.
And you can tell that I
am genuinely here with you
in this opera house because
if I were a hologram,
I would have asked them to
make me look a little taller.
Now, unfortunately,
we've just heard
that my father's molecules
have taken a detour via
distant galaxy.
And so, in a short delay before
he quantum teleports himself
into our company, I thought
I'd use this opportunity
to tell you a little
bit more about him.
As I'm sure, you can
imagine, I'm often asked,
"What is it like to be
Stephen Hawking's daughter?"
"What is that like?"
Recently, I read an account
that an astronaut wrote
about travelling in
space and he said,
"Flying in space is
a strange combination
of the deeply ordinary
and prosaic along
with the mind bogglingly
incredible," and that ladies
and gentlemen, if
you can imagine,
as I stand here wondering
if my father is going
to appear tonight, or whether
we will have just an opera house
full of static, is what it's
like to be Stephen
Hawking's daughter.
My father is of course at
the same time both iconic
and immediately recognisable
and yet enigmatic and baffling.
It's often said that we're all
dealt a hand of cards in life
and that the art of
living is to know how
to play the cards you hold.
And so, with that
in mind, I thought,
we would take a sneak
look at the cards
in Stephen Hawking's hand.
So, could we pull out our first
card from the pack please?
The adventurer, my father
has travelled the world
from Antarctica, Easter Island,
Russia, China, Japan, Iran,
India, many exotic locations.
And I think he inherited
his adventurous nature
from his parents who are
both intrepid travellers.
My grandfather, Frank
Hawking, was a doctor
of tropical medicine
who did pioneering work
on malaria and bilharzia.
And Frank spent much of his life
at work in India or in Africa.
And in fact, he was on the
lawn of the British embassy
in what was then called
Leopoldville then known
as the Belgian Congo, when
he heard of the outbreak
of the Second World War.
And as soon as he
heard the radio report,
he set off on a heroic
overland journey to East Africa
so he could get a
boat back to England
and enlist for the war effort.
My grandmother, Isobel Hawking,
was equally daring and intrepid.
She was the second child of
seven of the Scottish doctor
and she went to Oxford to
study philosophy, politics,
and economics in the
1930's, which is very unusual
for a woman at that time.
And while she was there,
she became a communist,
and she stayed a communist
for the whole of her life.
And granny had lots
of adventures.
When she was 95, she last slip
that she'd once been arrested
in New Orleans on suspicion
of being a brothel owner.
[ Laughter ]
So, no wonder the son of Isobel
and Frank saw no boundary
to human endeavour.
Could we pull again
please from the pack.
The scientist, of course,
my father is a theoretical
physicist and so,
he looks for ways to
use the laws of physics
to explain the universe.
And much of this
evening is devoted
to a discussion of his work.
His great discoveries that
the universe had a definite
beginning, that universe
has spontaneously emerged
without the need for a
creator to flip the on switch.
The black holes are not as
black as they've been painted,
or as I like to sum it
up, if you find yourself
in a dark place, don't despair
because there's always
a way out.
Could we draw again please.
Bond villain.
Recently, my father revealed
that his secret ambition is
to play a Bond villain.
[ Laughter ]
[ Applause ]
He likes to imagine himself
surrounded by Bond girls
and advanced technology
so he could say the
words, "So, Mr. Bond."
Unfortunately for
him, he's lacking
in a few vital attributes.
Bond villains, as a rule,
want to keep everything
for themselves, all
the inventions,
all the discoveries,
all the knowledge.
My father, in contrast,
has spent his life disseminating
scientific information.
He set out to share what he
knows with the human race
in the hope that this will help
with the advance
of civilisation.
Also, he doesn't have a cat.
Oh family man, when I
was child in the 1970's,
it was clearly very rare for a
disabled person to have children
and I based this on the way
that people used to stare at us
when we went out together.
Two small blonde children and a
man in an electric wheelchair,
people would openly stop what
they were doing and stare
and stare and stare
as we went past.
And we had lots of difficult
moments such as the manager
of a restaurant who asked us to
leave when we were in the middle
of lunch because he said we
were putting other diners off
their food.
Our family life took a lot
of persistence and courage
on the part of everyone
especially my mother who's role
in my father's life has been
captured now in a film called,
"The Theory of Everything".
And I hope now that if a
disabled person took their
children out for a
meal or for a walk,
they wouldn't receive the kind
of treatment we did back then.
And I also hope that the story
of our family gives courage
to anyone who's family life
doesn't look quite the way other
people think it should.
[ Applause ]
Communicator.
My father is not only a
distinguished scientist
but he's one who's fought
to communicate his ideas
to a general public, believing
that scientific literacy
is crucial for everyone.
He's tried to find the
simplest and most engaging way
to get his ideas to the
widest possible audience.
His bestseller book, "A Brief
History of Time" received a lot
of flag for being a book that
people bought and didn't read.
So, to my joy, a few years
ago, I found a league table
of the books most often bought
and least read, and guess what,
Brief History is not on it.
This is the only publishing top
10 not to feature Brief History.
Oh, lady killer, so keen
he's jumped out of the pack.
Now, as his daughter
I don't really want
to talk about this one.
So, I'll just show you a nice
photograph of him with Marilyn,
although it could be Anne
Hathaway, Jessica Chastain,
Shirley MacLaine, Jane
Fonda or any of the others.
Let's move on.
[ Laughter ]
Hero. With so many achievements,
it's easy to forget
that my father suffered
for over 50 years
from a neurodegenerative
illness called ALS or MND.
This condition has taken away
his ability to move his muscles,
and it's also robbed him of
his natural speaking voice.
So now, he communicates
through a computer
and this computer is
controlled by an infrared device
on the side of his
glasses which he operates
by the twitch of a cheek muscle.
Every word he says,
every lecture, book,
theory or discussion
has to happen this way.
You can try it yourself,
just twitch your cheek muscle
and see how many words do
you think you would produce
if you had to communicate
like this?
And there can be
pauses and delays
and they could happen this
evening, so I'd like you
to be patient and just think
about the effort that's gone
in to the communication
you will hear tonight.
And I just like you
to bear in mind
that of all the cards we've
drawn this evening, I think,
hero is the most fitting of all.
And now, it is time to
hear from the man himself,
hopefully he has arrived.
Let me have a look and see.
Dad, are you there?
Is there anybody out there?
[ Laughter ]
[ Applause ]
Well, good evening Cambridge.
This is my father,
Stephen Hawking,
and here we have John Ward
[assumed spelling] who's his
technical assistant.
Can you hear us?
>> Hello to the opera house.
>> Hello, John, hello.
[ Applause ]
Dad, it's lovely to
see you but I just have
to say you are a little late.
>> I'm operating on [inaudible].
>> Of course you are.
Ladies and gentlemen,
Stephen Hawking.
[ Applause ]
>> Hello, can you hear me?
>> [Simultaneous] Yes.
[ Applause ]
>> I can hear you too.
Thank you for being
here this evening.
Although I would love
to be there in person,
the idea of being the first
person to appear as a hologram
on the stage at the opera house
is too good an offer to refuse.
[ Laughter ]
When I do other speeches,
I'm not able to do this.
[ Laughter ]
I must point out that this is
not the first time I have been
a hologram.
I was supposedly represented by
a hologram in an early episode
of "Star Trek: The
Next Generation."
In the episode, I was playing
poker with Isaac Newton,
Albert Einstein,
and Commander Data.
[ Laughter ]
[ Applause ]
I won.
[ Laughter ]
I was unable to cash
in my winnings
of 140 Federation credits.
[ Laughter ]
I approached Paramount Studios
but they didn't know
the exchange rate.
[ Laughter ]
My performance was outstanding.
I was very convincing as myself.
[ Laughter ]
Almost as convincing
as Eddie Redmayne.
[ Laughter ]
It is thought to be a
subject of a Hollywood movie
and it has put me in
a reflective mood,
so I hope you will forgive me
for looking back over my life
in how our understanding
of the state
of the universe has changed.
I will also try to look forward
beyond the present horizon.
I was born on January 8th
1942, exactly 300 years
after the death of
Galileo, however,
I estimate that about 200,000
other babies were also born
that day.
[ Laughter ]
I don't know whether any of
them were later interested
in astronomy.
I was born in Oxford even
though my parents were living
in London.
This was because
Oxford was a good place
to be born during World War II.
The Trumans had an agreement
that they would not bomb Oxford
and Cambridge in return for the
British not bombing Heidelberg
and Gottingen.
It is a pity that
this civilised sort
of arrangement couldn't have
been extended to north cities.
We live in a tall narrow
Victorian house in Highgate,
which my parents had bought
very cheaply during the war
when everyone thought London
was going to be bombed flat.
In fact, a V-2 rocket landed
a few houses away from ours.
I was away with my mother
and sister at that time,
and fortunately, my
father was not hurt.
For years afterwards, there was
alert bomb site down the road
in which I used to play.
At that time, during
and just after the war,
Highgate was a scenario in
which a number of scientific
and academic people live.
In another country, they would
have been called intellectuals
but the English have
never admitted
to having any intellectuals.
[ Laughter ]
All of the parents sent their
children to Byron House School
which was a very progressive
school for those times.
I remember complaining
to my parents
that they weren't
teaching me anything.
They didn't believe in what
was in the accepted way
of drilling things into you.
Instead, you were
supposed to learn to read
without realising you
were being taught.
In the end, I did
learn to read but not
until the fairly
late age of eight.
In 1950, my father's place of
work moved to the northern edge
of London so my family
moved nearby
to the cathedral
city of Saint Albans.
I was sent to the
high school for girls
which despite its name took
boys up to the age of 10
but later I went to
Saint Albans school.
I was never [inaudible]
about halfway up the class
that was a very bright class.
[ Laughter ]
My class record was very untidy
and my handwriting was the
despair of my teachers.
But my classmates gave
me the nickname Einstein
so presumably they saw
signs of something better.
When I was 12, one of my friends
bet on other friend a bag
of sweets that I would
never come to anything.
I don't know if this bet was
said or settled and if so,
which way it was decided.
[ Laughter ]
I had six or seven close
friends and we used
to have long discussions and
arguments about everything
from radio-controlled
models to religion.
One of the things we
talked about was the origin
of the universe and
whether it required a got
to create it and set it going.
I had heard that light
from distant galaxies was
shifted towards a red end
of the spectrum and this
was supposed to indicate
that the universe was expanding.
But I was sure there
must be some other reason
for the red shift.
Maybe light got tired and
more red on its way to us.
An essentially, unchanging
and everlasting universe
seem so much more natural.
It was so only after
the discovery
of the cosmic microwave
background about two years
until my PhD research that
I realised I had been wrong.
My father was very
keen that I should go
to Oxford or Cambridge.
He himself had gone to
university college, Oxford,
so he thought I should
apply there.
But at that time, university
college had no fellow
in mathematics so I had
little option but to try
for a scholarship
in natural science.
I surprised myself
by being successful.
In the end, I have wound up
being a professor of mathematics
but I have not had any formal
direction in mathematics
since I left Saint Albans
School at the age of 17.
I have had to pick up
what mathematics I know
as I went along.
When I used to [inaudible]
undergraduates,
I would keep one week ahead
of them in the course.
[ Laughter ]
At Oxford, the physics
course was arranged in a way
that made it particularly
easy to avoid work.
I did one exam before I went up
then had three years at Oxford
with just the final
exams at the end.
I once calculated that I did
about a thousand dollars work
in the threes years I was
there, an average of $1 a day.
I am not proud of this.
I am just describing my attitude
at that time shared by most
of my fellow students.
Because of my lack of
work, I had planned to get
through the final exam by doing
problems in theoretical physics
and avoiding questions that
required factual knowledge.
[ Laughter ]
But I didn't sleep the
night before the exam
because of nervous tension
and so I didn't do very well.
I was on the borderline between
the first and second last degree
and I had to be interviewed
by the examiners
to determine which I should get.
In the interview, they asked
me about my future plans.
I replied that I
wanted to do research.
If they gave me a first,
I would go to Cambridge.
If I only got a second,
I would stay in Oxford.
[ Laughter ]
They gave me a first.
[ Laughter ]
I was 20 in October 1962 when
I arrived in Cambridge at then,
the Department of
Applied Mathematics
and Theoretical Physics.
I had applied to
work with Fred Hoyle,
the most famous British
astronomer at that time.
I say astronomer because
cosmology then was hardly
recognised as a legitimate
field, however,
Hoyle had enough
students already
so to my great disappointment,
I was assigned to Dennis Sciama
of whom I had not heard.
But it was just as well I
hadn't been a student of Hoyle
because I would have been drawn
into defending a
steady state theory,
a task which would have
been harder than getting
across the Harbour
Bridge at peak hour.
[ Laughter ]
I hadn't done much mathematics
in the very easy physics course
at Oxford so Sciama suggested
I work on astrophysics.
But having been treated
out of working with Hoyle,
I wasn't going to do something
boring like Faraday Rotation.
I had come to Cambridge
to do cosmology
and cosmology I was
determined to do.
At that time, cosmology
and gravitation were
neglected fields
that were right for development.
So, I read all the textbooks on
general relativity and travelled
up to hear relativity lectures
at Kings College,
London each week.
I followed the words
and equations
but I didn't really get a
good feel for the subject.
At that time, it became clear
something was not quite right
with me.
Already in Oxford, I had noticed
that I could no longer row
a Sculling boat properly.
The Christmas after arriving
in Cambridge, I went home.
It was a very cold winter
and my mother persuaded me
to go skating on the lake
in Saint Albans even though
I knew I was not up to it.
I fell over and had great
difficulty getting up again.
My mother realised something was
wrong and took me to the doctor.
I spent weeks in Barts
Hospital and had many tests.
They never actually told me what
was wrong but I guessed enough
to know it was pretty bad
so I didn't want to ask.
In fact, the doctor who
diagnosed me lost his hands
of me and I never
saw them again.
He felt that there was
nothing that could be done.
In fact, my father became
my doctor and it was to him
that I turned for advice.
At first, I became depressed.
I seem to be getting
worse really rapidly.
There didn't seem any
point working on my PhD
because I didn't know if I would
live long enough to finish it.
But then, the condition
developed more slowly
and I began to make
progress in my work.
After my expectations
had been reduced to zero,
every new day became
a bonus and I began
to appreciate everything
I did have.
While there is life,
there is hope,
and there was also a young
woman called Jane whom I had met
at a party.
Getting engaged lifted
my spirits and I realised
if we were going to get married,
I had to get a job
and finish my PhD.
I began to work hard
and I enjoyed it.
The big question in cosmology
in the early '60s was
that the universe
has a beginning.
Many scientists were
instinctively opposed
to the idea because
they felt that a point
of creation would be a place
where science brought down.
One would have to appeal to
religion in the hand of God
to determine how the
universe would start off.
Two alternative scenarios
were therefore put forward.
One was the Steady State Theory
in which has the
universe always expanded.
A new matter was
continually created
to keep the density
constant on average.
By the time I began my research,
the Steady State Theory
was already in trouble
with observations but the
final nail in the coffin came
with the discovery
of a faint background
of microwave radiation in 1964.
The only reasonable
interpretation
of the background is
that it is radiation left
over from an early, very
hot and dense state.
As the universe expanded, the
radiation would have cooled
until it is just a faint
remnant we observe today.
But there was a second
alternative to a beginning
in time which is a bouncing
or a cyclic universe.
Perhaps a universe had a
previous contracting face
and that it had bounced from
contraction to expansion
at a high but finite density.
This was clearly a
fundamental question
and it was just what I needed
to complete my PhD thesis.
Two Soviet scientists, Lifshitz
and Khalatnikov had claimed
to have proved that contraction
and general relativity
without any special symmetry,
would always lead to a bounce
with the density
remaining finite.
This result was very convenient
for Marxist materialism
because it avoided
awkward questions
about the creation
of the universe.
Lifshitz and Khalatnikov were
members of the old school
and general relativity, that is,
they wrote down the
massive system of equations
and tried to guess a solution.
But it wasn't clear that the
solution they found was the most
general one.
A new approach was
introduced by Roger Penrose
which didn't require solving the
field equations explicitly just
certain general properties
such as that energy is positive
and gravity is attractive.
Penrose had showed that once
a dying star had contracted
to a certain radius, there would
inevitably be a singularity,
a point where space and
time came to an end.
I realised that similar
arguments could be applied
to the expansion
of the universe.
In this case, I could prove
there were singularities
where space time
had a beginning.
So Lifshitz and Khalatnikov
were wrong.
General relativity predicted
that the universe
should have a beginning.
Up to 1970, my main
research interest was
in the big bang singularity
of cosmology rather
than the singularities or black
holes that Penrose had shown
with occurring collapsing stars.
My work on black holes began
with a eureka moment a few days
after the birth of
my daughter, Lucy.
While getting into bed,
I realised that I could
apply the black holes,
the [inaudible] theory
I had developed
for singularity theorems.
In particular, the area of
the horizon, the boundary
of the black hole
would always increase.
When two black holes
collide and merge,
the area of the final black
hole is greater than the sum
of the areas of the
original holes.
That suggested that the
area of the black hole was
like what is called the
entropy in thermodynamics.
It would be a measure
of how many states a black
hole could have on the inside
from the same appearance
on the outside.
But the area couldn't
actually be the entropy
because as everyone thought they
knew black holes were completely
black and couldn't
be in equilibrium
with thermal radiation.
There was a golden age
in which we solve most
of the major problems
in black hole theory.
This was before there was
any observational evidence
for black holes.
In fact, we were so successful
with the classical general
theory of relativity that I was
at a bit of a loose end in
1973 after the publication
with George Ellis of our book,
"The Large Scale
Structure of Space-Time".
My work with Penrose had shown
that general relativity brought
down that singularities so
the obvious next step would be
to combine general relativity,
the theory of the very large
with quantum theory, the
theory of the very small.
I had no background
in quantum theory
and the singularity
problem seem too difficult
for a [inaudible] at that time.
So, as a warmup exercise,
I considered how particles
and fields governing
by a quantum theory would
behave near a black hole.
In particular, I
wondered, can one have atoms
in which the nucleus is a tiny
primordial black hole formed
in the early universe?
To answer this, I
studied how quantum fields
or particles would
scatter off a black hole.
I was expecting that part of an
incident wave would be absorbed
and the remainder scattered.
But to my great surprise, I
found there seem to be emission
from the black hole itself.
At first, I thought this must
be a mistake in my calculation.
But what persuaded me
that it was real was
that the emission was
exactly what was required
to identify the area of the
horizon with the entropy
of the black hole that is
summed up in this simple formula
which expresses the
entropy in terms
of the area of the horizon.
And the three fundamental
constants of nature, C,
the speed of light, G,
Newton's constant of gravitation
and H bar, Planck's constant.
I am proud to have
discovered it.
Later work uncovered the
deep reason for this formula.
General relativity can be
combined with quantum theory
in an elegant manner
if one replace its ordinary
time by imaginary time.
This is called a
Euclidean approach
because it makes time become
a fourth direction of space.
The Euclidean space
time is smooth
and contains no singularity
at which the equations
of physics could not be defined.
It solved a fundamental problem
that the singularity theorems
of Penrose and myself had raised
that predictability would break
down because of the singularity.
The radiation from a black
hole would carry a wee energy
so the black hole will
lose mass and shrink.
Eventually, it seems the black
hole will evaporate completely
and disappear.
And this raised a problem that's
direct at the heart of physics.
My calculation showed that the
radiation was exactly thermal
and random as it has to be if
the area of the horizon has
to be the entropy
of the black hole.
So how could the
radiation leftover carry all
of the information about
what made the black hole.
But if information is
lost, this is incompatible
with quantum mechanics.
And this paradox had
been argued for 30 years
without much progress which is
what often happens in research.
But if you get stuck, it's no
good getting furious you just
have to keep thinking about
the problem while working
on something else.
Eventually, I found what
I think is its resolution.
Information is not
lost in black holes
but it is not returned
in a useful way.
It is like burning
an encyclopaedia.
Information is not lost but
it is very hard to read.
[ Laughter ]
In fact, Kip throne and I
had a pack with Sean Preskill
on the information paradox.
I gave Sean baseball
encyclopaedia.
Maybe I should have just
given him the ashes.
[ Laughter ]
The fact that I used to think
that information was destroyed
and black holes my
biggest blunder.
Well, at least it was my
biggest blunder in science.
[ Laughter ]
During the 1970's I had been
working lately on black holes
but my interest in cosmology
was renewed by the suggestions
that the early universe
had gone through a period
of inflation or reexpansion.
In which its size grew at
an ever increasing rate
like the way prices
go within the shops.
In early 1982, I wrote
a preprint for opposing
that the [inaudible] in our
universe could be created
by a quantum effects
during inflation.
This was basically the
same mechanism as radiation
from a black hole horizon
except that this time it came
from the cosmological horizon.
I had used Euclidean methods
earlier with Gary Gibbons
to work out the temperature
of this interspace.
We held enough field workshop
in Cambridge at summer attended
by all the major
players in the field.
At this meeting, we established
most of our present picture
of inflation including
the all-important density
fluctuations which gives
rise to galaxy formation
and so to our existence.
Several people contributed
to the final answer.
This was 10 years
before fluctuations
in the microwaves light were
discovered by the Cobe Satelline
in 1993 so theory was
way ahead of experiment.
Cosmology became a precision
science in under 10 years later
in 2003 when the first results
from the WMAP satellite.
WMAP produced a wonderful
map for the temperature
of the cosmic microwave strike
a snapshot of the universe
at about one hundred
of its present age.
The irregularities you see
are predicted by inflation
and they admitted
that some regions
of the universe had a slightly
higher density than others.
The gravitational attraction
of the extra density slows
the expansion of that region
and can eventually
cause it to collapse
to form galaxies and stars.
So look carefully at the map
of your microwave strike.
It is the blue print for all
the structure in the universe.
Superseding WMAP, today,
there is the Planck satellite
with a much higher
resolution map
of the universe you
see here on stage.
Planck will test our
theory [inaudible]
and may even detect the imprint
of gravitational waves
predicted by inflation.
This would be quantum gravity
written across the sky.
And the original
scenario for inflation was
that the universe began with
the big bang singularity.
As the universe expanded, it
was supposed somehow to get
into an inflationary state but I
thought this was unsatisfactory.
Unless one knew what came out
of the initial singularity,
one could not calculate how
the universe would develop.
Cosmology would not have
any predicted power.
What was needed was a space
time without singularity
like in the Euclidean
version of the black hole.
After the 1982 workshop
in Cambridge, I spent time
at the Institute of Theoretical
Physics in Santa Barbara.
I talked to Jim Hartle about how
to apply the Euclidean
approach to cosmology.
According to his approach,
the quantum wave function
of the whole universe is given
by a fine [inaudible] when some
over a certain class of
histories in imaginary time.
Because imaginary time behaves
like another direction in space,
histories and imaginary
time can be closed surfaces
like the surface of the earth
with no beginning or end.
Jim and I concluded that this
was the only natural choice.
We formulated a no boundary
proposal the boundary condition
of the universe is that
it has no boundary.
We had sidestepped
the scientific
and philosophical difficulty
of time having a beginning
by turning it into a
direction in space.
In this picture, the universe
will be spontaneously created
out of nothing.
It will start out almost
completely smooth except
for the tiny departures
predicted by inflation
which then gives rise
to all of the structure
in the universe we see above us.
Around the time of
my no boundary work,
I decided to light a
write a popular book.
I thought I might
make a modest amount
to help separate my children
at school and the rising costs
of my care, but the main reason
was because I enjoyed it.
While I was writing it,
I visited Switzerland
and I became critically
ill with pneumonia
and lost my voice
tube to a tracheotomy.
But I kept putting a lot
of effort into the book
because I think it's
important for scientists
to explain their work
particularly in cosmology.
I never expected "A
Brief History of Time"
to do as well as it did.
Not everyone may
have finished it
or understood everything
what they read but they
at least got the idea that we
live in a universe governed
by rational laws that we
can discover and understand.
There are many ambitious
experiments planned
for the future.
We will match with the positions
of billions of galaxies
and with the help
supercomputers like COSMOS,
we will better understand
our place in the universe.
Perhaps one day, we will be
able to use gravitational waves
to look right back into
the heart of the big bang.
Most recent advances in
cosmology have been achieved
from space where there are
uninterrupted use of our vast
and beautiful universe.
But we must also
continue to go into space
for the future of humanity.
I don't think we will
survive another thousand years
without escaping beyond
our fragile planet.
I therefore want to encourage
public interest in space
and I've been getting
[inaudible].
[ Music ]
So let me finish by reflecting
on the state of the universe.
It has been a glorious time
to be alive and doing research
in theoretical physics.
Our picture of the universe
has changed a great deal
in the last 50 years
and I'm happy
if I have made a
smaller contribution.
The fact that we humans who
are ourselves mere collections
of fundamental particles
of nature have been able
to come this close
to an understanding
of the laws governing us in our
universe is a great triumph.
I want to share my excitement
and enthusiasm about this quest.
So remember to look at the
stars and not down at your feet.
Try to make sense of
what you see and wonder
about what makes
the universe exist.
Be curious.
And however difficult life may
seem there is always something
you can do and succeed at.
It matters that you
don't just give up.
[ Applause ]
Thank you for listening.
[ Applause ]
>> Stephen's going
to take a short break
but he's coming back
a little later
to answer some questions
from the audience.
And we're going to use this
opportunity, Lucy and I,
to talk about the film,
"Theory of Everything."
So, let's sit down.
We're going to see some film
clips in a moment but first,
I've just got my observation
that for me it was really weird
to go and see a film where I
know most of the characters
in the film, the real people.
But--
>> I felt very much
the same, Paul,
>> How much more weird--
>> Yes.
>>-- it would be for you--
>> It was even stranger.
>> -- when you're
appearing in the film.
>> Yes because I was watching
the film and you get very drawn
into the story of these two nice
young people, Jane and Stephen,
and I was watching thinking,
oh, I like these people.
Aren't they lovely?
And good they got together,
isn't that wonderful.
And now, oh, they've had a baby.
And you go, oh, my
goodness, that's me.
That was very-- a very,
very strange moment.
A few years ago, a very wise
friend of mine said to me,
he said, you have
the sort of childhood
that Hollywood makes
movies about.
And I thought well that could
never happen, and lo and behold.
>> So when I saw the film,
some of the characters
seem fairly believable
and them others didn't seem
quite like the real people.
Were there some that
stood out for you
as that's just like so and so?
>> The portrayal of my father
by Eddie Redmayne
is the performance
that has received a huge amount
of attention and accolades
because it is so
pin point accurate.
And I think Eddie
Redmayne put so much effort
into his performance
and so much research
and so much feeling into it.
And he did such a great job,
he's a very talented actor.
So that was absolutely perfect.
I was played by a very
lovely six-year old
who did some great skipping.
That was good--
>> Right.
>> -- good skipping.
>> Right.
>> By me.
>> Yeah you never
seem to grow up much.
>> I know.
I didn't. The only
thing the timeline
in the film is slightly
mysterious because it is
after all a piece
of story telling.
So I do seem to be six
for rather a long time.
>> Right. I have to say, I loved
the Dennis Sciama characters
because I knew Dennis very
well and he was just like that.
>> Yes.
>> But Roger Penrose is
nothing like the real Roger.
>> Quite a few scientists have
complained to me about to me
about the PhD viva scene because
it's very quick in the film.
It's just a few questions and
someone put to me the other day,
they said that that PhD viva
was four and a half hours long.
And I did have to say I
don't think anyone's going
to make a film about
your PhD viva, sorry.
>> Well let's take a look at--
>> Yes.
>> -- one of the clips
from the film, if we may.
>> [Background music]
Sot that's tightened up.
As you can see, it's
height-adjustable
and we can change the angle
to whatever Steve wants it at.
You know, it's cutting-edge.
>> So, how does it work?
>> It uses a very
simple interface
that scans through the alphabet.
It selects each letter
one at a time.
I mean, using this technique,
the professor can expect
to write about four
words per minute.
>> Good. Better than
one a minute.
>> Yes, and what I've done
is taken the components
from a telephone
answering system, actually,
to convert the written text
into synthesised speech.
I mean, the voice sounds
a little bit robotic, but,
shall we give it a try?
>> Great.
>> Here's the clicker.
>> Right hand?
>> There you go.
Welcome to the future.
>> My name is Stephen Hawking.
>> It's American.
>> Is that a problem?
>> Oh, my goodness.
Well, is there another voice?
>> That's the only one
they have at the moment.
>> I think it's great.
[ Laughter ]
[ Applause ]
>> I like that scene, I
like that scene very much.
As very much as I
remember the introduction
of the computerised
speech machine.
And--
>> With the American voice.
>> The American voice.
And then every--
>> And Steve himself was always
use to make a point about.
>> He did, yes.
He used to say, I'm sorry
about my American accent.
And of course when
he was in America,
people would be like why?
It did lead to a lot of people
thinking that he was American.
>> That's right.
>> So for a long
time, people believed
that in fact he was American.
But that was genuinely the voice
that was available at that time.
And of course technology
has moved on
and they can create all
sorts of voices now.
They can put a lot of texture
and variation and accent
and make an age of voice.
>> It could be an
Australian female.
>> He could be a-- he could be
pretty much anything he want to
but that voice is so
closely associated--
>> I think it is.
>> -- with himself now
and his personality
and I think people
associate that sound with him.
And so, you know, he doesn't
want to change it now.
>> Now we both remember the time
when he didn't have
that device--
>> Yes.
>> And when he-- his speech
became harder and harder
to understand and I can remember
these conversations over tea
that we were talking
about struggling
to follow what he was saying.
But there'd always be a student
who would translate Stephen
says this, Stephen says that.
So there'd be this sort of
three-way conversation going on.
And I think you had
to this as well--
>> Well yes.
I mean--
>> -- even though you
were quite younger--
>> As children, my brother
and I were very good
at understanding our father.
We could understand exactly what
he was saying even though his
voice deteriorated and it had
a sort of rusty quality to it.
But my brother and I could pick
out everything he was saying
even though we didn't actually
understand what he was saying.
So as children, my father would
something, we'd parrot something
about the entropy of black holes
or the laws of thermodynamics.
And I'm only about seven.
And then I think, I actually
have no idea what I just said.
And you'd see the
scientists he was talking to,
their face would clear or
it would crowd and then be--
and they'd say something back
and we'd be there in this almost
like a simultaneous translator.
So maybe I caused some
problem, maybe I--
maybe some of it was
lot in translation.
>> Right.
>> Let's watch another clip.
>> Yes. Let's.
>> In 1979, you talked about
the possibility of a theory
of everything being discovered
before the end of the century.
>> I now predict
that I was wrong.
[ Laughter ]
>> Professor Hawking.
You have said you do
not believe in God.
Do you have a philosophy
of life that helps you?
[ Music ]
>> Well that was obviously
a very powerful moment
in the film.
What is the interpretation
you put on it
on the symbolism there?
>> Well, some people
said they didn't
like that moment in the film.
But I found it really
mesmerising and very,
very emotional because
I used to have a dream
in which I would
see my father walk
and I've never actually
seen him walk.
And then when I saw that in
the movie for the first time,
it was like something
at my subconscious
projected onto a movie screen.
And it was just overpowering
in its emotional impact for me
because it was just though
I saw my dream come to life
as though I saw my father
and what he would look
like in middle age
without his condition.
And it was very, very moving for
me and it's a sort of reverie,
it's going inside the
mind of somebody who would
like to be free and be able
to do a very simple thing
which is stand up,
walk down a flight
of stairs and pick up a pen.
And so for me, that was
extremely emotional.
I know it didn't resonate
for everybody but I think--
I said to the director
in the end,
thank you for putting
that piece.
And even if you really
put in for me,
the one viewer, thank
you anyway.
>> Well Lucy, it's been
wonderful to give your insights
as the member of the
family as well as someone
who is following the signs,
you know the words at least.
>> I do, yes.
>> And what we're going to do
is get your father's reactions
of the film.
So ladies and gentlemen,
let's thank Lucy once again.
>> Thank you.
[ Applause ]
>> And by miracles of modern
technology bring Stephen back.
Stephen are you there?
Hello. So, well Lucy
and I have been talking
about her response
to the movie--
>> I am back, yes.
>> What is yours?
Tell us your response,
how did you feel about it?
>> I was apprehensive about
the film because it was based
on a book by my former wife.
[ Laughter ]
But I was reassured when I
read the script and even more
so when I saw the screening.
It was surprisingly
honest about our marriage.
There were many moments
in the film
that were quite different
from reality.
For example, the film has made
discover Hawking radiation soon
after Lucy was born.
In reality, that was when
I worked out what happens
when black holes merged.
But it doesn't matter.
I won't tell him how to make
movies if they don't tell me how
to solve the mysteries
of the universe.
[ Laughter ]
I thought Eddie Redmayne's
portrayal of me was very good.
He spent time with people
with ALS to be authentic.
At times, I almost
believed he was me.
Those who have seen the movie
said it made a big impact.
To me, it was close as I'll ever
get to travelling back in time.
I've been telling everyone
that the film should have more
physics and fewer feelings.
[ Laughter ]
But I am a physicist
and not a psychoanalyst
so I think that's probably
a fair comment from me.
I think all films should
have more physics in them,
although I realised
this is a point of view
which may not catch
on in Hollywood.
[ Laughter ]
>> Well Stephen, now
quite a few people
in the audience have
same thing questions.
But of course we've have
to be very selective
as to those we will
feature tonight.
And I'm going to
take them one by one.
The first is from Maged William
[assumed spelling] and it says,
in your book "The Grand Design",
you explained how the equations
that permit the formation
of a habitable earth is
so delicately arranged.
Don't you think that
the most logical answer
to why the universe is as it
is, is that it's been auditing
through existence by some
intelligent supernatural being
or God.
What do you say to that?
>> No.
>> All right.
Thank you.
>> I find very little
logic to that answer.
[ Applause ]
It actually [inaudible]
an answerable questions
such as what was this god doing
before creating the universe?
Was he building hell for
people who ask such questions?
[ Laughs ]
>> Well, the next question.
[ Laughter ]
-- is from-- I hope I'm
pronouncing this right.
Avidez Gazariean [assumed
spelling] I should say
incidentally that as you
know, Stephen can see us just
as we can see him
so if Avidez is
in the audience,
please stand up.
But the question is,
professor Hawking,
you've been quoted a saying
that physics would
be more interesting
if the Higgs boson
haven't been found.
I'm not going to go
into a description
about the Higgs boson
is, you should know
if you've been reading
your newspapers.
Now, that the Large
Hadron Collider is running
at much higher energies, there
is a hope among some scientists
that it would discover
new particles.
In you opinion, how much would
such a discovery change
our current understanding
of matter and the universe?
I lost another bet
over the Higgs boson.
I really need to stop gambling.
[ Laughter ]
My daughter thinks I
have a problem but I
like to make bets in physics.
It tweaks attention on
important questions.
I do hope that the LHC
can find new particles.
We might be lucky and find
supersymmetric partners
for the known particles.
This would revolutionise our
understanding of the universe.
There is hope this evidence
will be found but this time,
I'm not going to
put money on it.
[ Laughter ]
>> Well, we have
a final question
from Samantha Sue
[assumed spelling].
Samantha please stand
up if you're out there.
What do you-- Here we go,
what do you think is
the cosmological effect
of Zayn leaving One Direction
and consequently breaking
the hearts of millions
of teenage girls
across the world.
And I confess, I have no idea
of what I'm talking about
but Stephen, you follow these
things much more closely
than I do.
So, what do you say to Samantha?
>> Finally, a question
about something important.
[ Laughter ]
My advice to any
heartbroken young girl is
to pay close attention to the
study of theoretical physics.
[ Laughter ]
Because one day, there may well
be proof of multiple universes.
It would not going to be beyond
[inaudible] of possibility
that somewhere outside
of our own universe lies
another different universe.
And in that universe, Zayn
is still in One Direction.
[ Laughter ]
Because [inaudible] like to note
that in another possible
universe,
she and Zayn are
happily married.
>> Well, thank you Stephen.
Apparently, you've just mended
many broken hearts, at least,
those of teenage girls I see.
But I'm afraid it doesn't
mean so much to me.
Well, time is an endlessly
fascinating subject
but there's never enough of it.
We're approaching the end
of this fascinating evening.
I think it's only appropriate
that the last word should go
to Stephen Hawking himself.
So, ladies and gentlemen,
remember,
Stephen can see us
just as we can see him.
So, over to you Stephen.
Thank you Paul.
And thank you as well
to my daughter Lucy
for making the journey to
Australia on my behalf.
And especial thanks to
the science and technology
that has brought
me to you tonight.
We have a rather ambivalent
attitude to science at present.
We have come to expect a
steady increase in the standard
of living that science and
technology have brought
but people just left signs
because they don't understand it
or feel they can control it.
The popularity of science
fiction like "Star Trek" is
because this is a
form of science
with which people feel safe.
But an understanding of science
fact would lead their fears
to rest much better.
What can be done to harness
this fascination with science
and give people the background
in it to make informed decisions
on subjects like the greenhouse
effect, nuclear weapons
or a genetic engineering.
The pieces must be what
is taught in schools.
But school science is
often present in a dry
and uninteresting manner.
When I wrote "A Brief
History", I was advised
that each equation I
included will half the sales.
[ Laughter ]
I included one, Einstein's
famous equation,
E equals MC squared.
Perhaps, I would have sold
twice as many copies without it.
[ Laughter ]
Scientists and engineers tend to
express their ideas by equations
because they need to know the
precise value of quantities.
But for most people,
a qualitative rather
than quantitative
understanding is sufficient.
This can be conveyed by words
and diagrams without the need
for complicated equations.
School science can provide a
basic framework but the rate
of progress is now so rapid
that there are always new
developments that have occurred
since one who has set
school or university.
Top your science books and
articles can help to put
across these new developments.
But only a small proportion
of the population reads even
the most successful book.
Television is one way to
reach a truly mass audience,
but television is
communication one way only.
Now, with the internet, people
can answer back and interact.
In a way, the internet connects
us all together like the neurons
in a giant brain with such an
IQ what won't we be capable of.
I will end on a quote from one
of my favourite science
thinkers.
The late great Mr. Spock.
[ Laughter ]
Live long and prosper.
Thank you for listening.
[ Applause ]
Now, [inaudible].
[ Noise ]
[ Applause ]
