(STEPHEN HAWKING) Let me take you back in time
to a place without the wonders of the modern world.
500 years ago, the Earth was dark,
a place of mystery and superstition.
But then science changed everything.
This series will tell the stories of the British scientists who changed the world.
We have asked some of the great scientists and inventors of today
to tell us about their heroes.
Now let's start her up.
It opened up a whole new world of the very small.
Heat was Thomson's big idea.
For me, Hunter is a true hero.
Exciting possibilities.
He made science in Britain really matter.
Britain has a tremendous scientific legacy that most people know little about.
We want to set the record straight and put science back on the map.
The world is full of wonders, but they become more wonderful
when science looks at them.
Our story began with a handful of men
who started to solve the mysteries of the universe.
Those who came after built on their discoveries and harnessed
steam to make power, hydrogen to fly and electricity to light up the world.
But now we take a darker turn.
The first half of the 20th century was dominated by war.
But war brings with it change alongside horror
and innovation alongside courage.
This film is the story of some of the greatest of the backroom boys,
the scientists and engineers,
who helped us come out of the darkness of war.
(JIM AL-KHALILI) A German reconnaissance pilot
flying over Britain in the autumn of 1939
would look down on a country preparing for war.
He'd see mysterious steel towers ranged along the coast,
and wonder what they were for.
He would see a country that seemed open to attack and even invasion.
The English Channel had kept out Napoleon,
but by 1939, the question was, could it keep out Hitler?
In the age of the aeroplane,
Britain seemed particularly vulnerable to attack.
The First World War had already revealed what airpower could do.
On 25th May, 1917,
21 giant twin-engined Gotha biplanes bombed Folkestone.
They killed 95 people and injured 192 others.
In the 1920s, the great fear was that any new war
would bring massive bombing raids and huge civilian casualties.
So the British built an early warning system which looked like this.
This concrete sound mirror was built in 1928.
It's 20 feet across. It cost a few thousand pounds in today's money,
and didn't work very well.
The operator would stand with a stethoscope in front of it
in the hope of picking up the tell-tale sounds of enemy bombers on their way,
if he was lucky.
The results would be affected by the weather,
and by other distractions, like the sounds of the propellers of ships out at sea.
Obviously something far better was needed.
The first idea for a better system
was like something out of a science fiction film.
In the early 1930s, British intelligence picked up rumours
that German scientists had invented a death ray,
using high-power radio signals to destroy men and aircraft.
The Air Ministry realised that if the Germans had one of these,
then the British wanted one too.
A committee was set up, and a prize of 1,000 was offered
to the first person who could kill a sheep at 100 yards using a death ray.
The prize was never claimed.
So in January 1935, the Committee turned to a man
who they hoped would be able to build them a death ray.
A personal hero of mine, a man whose ingenuity in the face of threat
would change the course of history.
Robert Watson-Watt.
Watson-Watt was a physicist and the government expert on radio waves.
He and a colleague set about calculating
the electromagnetic energy needed to put an enemy bomber out of action.
They quickly showed that a death ray couldn't possibly work.
But they had another idea, and when Watson-Watt submitted his report
to the Ministry, it contained the now famous sentence,
"Although it's impossible to destroy aircraft using radio waves,
"it should be possible to detect them
"using radio energy that bounces back from the aircraft's body."
The Ministry said, "Prove it."
Watson-Watt relished the challenge.
He was the son of a Scottish carpenter
and a proud descendant of steam pioneer James Watt.
In February 1935, on the very same day
that Hitler ordered the establishment of the Luftwaffe as a military air force,
Watson-Watt and his colleague Arnold Wilkins
set up their crucial experiment to detect distant aircraft.
They chose a secret location in Northamptonshire,
just a few miles from the BBC short-wave radio transmitter at Daventry.
The Birth of Radar Memorial.
"On 26th of February 1935, in the field opposite..."
Watson-Watt and Wilkins had arranged for an RAF bomber to fly overhead,
and they tuned their aerials in such a way that the receiving equipment in their van
wouldn't pick up the BBC signal directly,
but only the energy reflected by the bomber.
They found they could track the bomber as far as eight miles away
with blips on a cathode-ray tube.
It was the world's first radar reading.
The man from the Ministry rushed back to London to report success.
Watson-Watt and his colleagues were awarded a grant of 10,000
to build a prototype radar system.
They were given five years to detect an incoming enemy aircraft
at a range of 50 miles.
It took them just five months.
By 1939, there were 20 fully-operational radar stations
stretching all the way along Britain's vulnerable coastline.
20 miles away across the Channel,
the Luftwaffe looked forward to an easy victory,
and the benefits of a surprise attack.
August 13th, 1940.
Adlertag, Eagle Day,
the German codename for the start of Hitler's invasion of Britain.
Over a thousand German aircraft darkened the skies over southern England.
The Luftwaffe had estimated
that it would just take four days to destroy the RAF Southern Command.
All that stood in their way
were the vastly outnumbered British Hurricanes and Spitfires.
That and the secret weapon - Watson-Watt's radar.
It had worked in peacetime testing,
but would it work in the chaos of war?
For three tense months in the late summer of 1940,
the RAF and the Luftwaffe
fought out their deadly duel in the skies above southern Britain.
It was a close-run thing,
but Watson-Watt's radar made a key difference.
It meant Fighter Command knew when the German planes were coming,
and that meant they could get the precious few Spitfires and Hurricanes
into action in the right place at the right time
to intercept and destroy the enemy.
Radar gave Britain the edge,
and without it, the battle would have been lost.
Watson-Watt's invention made our modern world
with its busy skies possible.
Without it, planes would collide and ships would run aground.
And finding ways to hide from radar
is now the Holy Grail of military aircraft design.
(STEPHEN HAWKING) Planes like this would be impossible to fly
without another two British technological miracles
that were to come out of World War Two and help the Allies to victory.
The jet engine
and the computer.
My world, and yours, is run by computers.
70 years ago, they didn't exist,
except in the mind of a brilliant Cambridge mathematician
called Alan Turing.
Nobody can say where the thing he started is going to take the human race.
Alan Turing's story is an extraordinary one,
and I think we should begin at the end.
On 8th June 1954,
Alan Turing's housekeeper found him dead in his house near Manchester.
The postmortem report said it was cyanide poisoning.
His mother always thought it was an accident.
A few people thought he was assassinated.
The coroner's official verdict was suicide.
All three theories have something going for them.
Even his mother's accident theory is not as implausible as it sounds.
Turing did do chemical experiments and he did use cyanide.
The assassination theory, too, could at least point to a motive.
Turing was a security risk. He was eminently blackmailable -
a homosexual at the time when it was illegal -
and he had in his head
some of the most important secrets of the Second World War.
Turing was the presiding genius
of Britain's wartime code-breaking headquarters
and the man who created a code-breaking machine
that was the basis for all computer technology.
This fascination with the idea of a thinking machine
began with a book he was given when he was ten.
One chapter was called Where We Do Our Thinking.
The mind and how it worked would obsess Turing
for the whole of his short life.
At Sherborne School in Dorset,
Turing's passion for science set him apart.
When he was 15, the headmaster said, "He must aim at becoming educated.
"If he is to be solely a scientific specialist,
"he's wasting his time at a public school."
But his school did provide him with an experience
that would shape his life and ours.
Alan fell in love with a boy called Christopher Morcom.
He dreamed that they might go up to Cambridge together,
and Christopher duly won a scholarship in 1929.
But then, tragically, Christopher died of tuberculosis.
Alan was devastated.
In his anguish, he wondered whether there was any way
in which Christopher's mind might have survived the death of his body.
What was the relationship between a mind and a body?
Between mind and matter?
These questions lay behind Turing's determination
to analyse and understand the nature of thought.
He couldn't resurrect his dead friend,
but there was something he could do -
win a maths scholarship to Cambridge, just as Christopher had.
Turing wasn't just a scholar, he liked rowing and running.
He ran marathons. And it was here one day in 1935,
while he was out running in Grantchester Meadows,
that he had one of the greatest mathematical insights of all time.
His great insight was to see how an imaginary machine,
operating with very simple rules but with an infinite amount of time,
could solve any and all conceivable mathematical problems.
The so-called Turing machine
was a logical construct, not a real machine.
But with it, Turing had invented the concept of the programmable computer
years before anybody could see how to build one.
The full power of Turing's revolutionary ideas
would not be appreciated for years, even decades.
And Turing himself was about to get caught up
in something far away from the rarefied beauty of pure mathematics.
Even before war began, Turing's potential as a code-breaker
had been spotted.
So, at the outbreak of war, the 27-year-old Turing
was immediately assigned to Room 47 of the Foreign Office.
This was the postal address of the most secret place in Britain.
This is Bletchley Park, home of the code-breakers,
without whom we'd probably have lost the war.
10,000 people worked here, but in conditions of the utmost secrecy.
Many of them didn't even know what they were doing.
They were led by brilliant mathematicians, engineers,
statisticians, even chess grandmasters and crossword compilers.
And foremost among these quirky intelligences was Alan Turing.
This is Alan Turing's office in Hut 8 at Bletchley Park.
It's been reconstructed to be pretty much the way it would have been.
Turing's eccentricities were legendary and endearing.
He lived in a pub outside Bletchley
and he cycled into work wearing his gas mask,
not for protection against gas, but because he suffered from hay fever.
He chained his tea mug to the radiator
with a padlock for fear anybody else would steal it.
Most people thought he was eccentric,
everybody knew he was a genius.
This is what Turing and his colleagues at Bletchley Park were up against,
the German sophisticated coding device, Enigma.
It was used to encode messages
in a way that was going to be very, very hard to decode.
Imagine that I'm a German radio operator
and I want to send a message. It might be "heil Hitler".
I could just send it in clear...
BEEPING ..H, E, I, and so on.
Obviously people don't want to do that because people are going to read it.
So you have a machine to encode it.
Every day, Enigma was set up in a new way by resetting rotor wheels.
Depending on the day's starting rotor position,
Enigma replaced each letter by another through a labyrinth of switching wheels.
They scrambled the letters in ever-changing combinations.
With every key press, the code changed.
The receiver, on getting the message "SJFX", he would then set the rotors
to the correct starting position and then press S...
J, F, X.
"HEIL".
To put in perspective how difficult it was,
the number of possible combinations you would have to try,
just at random, in order to hit upon the answer by luck with the Enigma machine
was 158 million, million, million.
And compare that with the odds against your winning the Lottery,
which is a mere 14 million to one.
The Germans believed Enigma was unbreakable.
The British thought differently.
Mathematicians such as Turing and his colleagues
convinced the politicians that it was in principle possible
to break the Enigma code.
NEWSREEL: A convoy at sea,
one of the lifelines upon which the United Nations' war effort relies.
The prize for winning the Enigma lottery
would be Britain's survival.
The U-boat wolf packs in the North Atlantic
were sinking convoys every day and severing our lifeline to America.
All U-boat secret communications used Enigma.
Using captured machines and codebooks,
some very clever mathematics, intuitions, and imaginative guesswork,
the code-breakers tried to probe the Enigma system for weaknesses.
And they found them. Human error, repetition of certain phrases
or greetings, such as "heil Hitler", or patterns in weather forecasts, say.
But looking for these needles in the cryptographic haystack
took thousands of human hours.
Turing came up with a brilliant shortcut
in the hunt for the rotor settings.
It was an electromagnetic machine called "the bombe",
and it was Turing's first attempt
to put his idea of a mechanical brain into practice.
The daily task for the code-breakers was to try to work out
the starting position of the three wheels for that day.
Each one of these rotating drums represents one of the three wheels,
and as they spin around,
they are examining each of the possible positions of the wheel
to see whether it makes sense.
Now, the second trick, which was absolutely vital,
was that they made a guess as to what a message might possibly mean.
They knew, for example, that one of the things the Germans often sent
was weather forecasts and they knew the word for weather, which is "wetter",
W-E-T-T-E-R,
and so they were looking for a starting position of the wheels
which made sense on the assumption that the word being sent was "wetter".
They could read any message that was sent by that machine
during that day.
By the second half of 1941, Bletchley Park was reading
most of the signal traffic of the German navy.
Now, the vital North Atlantic convoys could be rerouted
to avoid the U-boat wolf packs,
and vital supplies could get through to beleaguered Britain.
What the U-boat commanders called their "happy time" was at an end.
The bombe wasn't a true computer,
but it laid the foundations for the development of one.
By the end of the war, Turing and his colleagues
had developed another code-breaking machine, Colossus,
which was indeed the world's first digital computer.
Without Alan Turing and the Bletchley Park code-breakers,
Britain might not have survived the Battle of the Atlantic,
and we would not have the computer-driven world we know today.
May 1941.
While Alan Turing and his code-breakers
eavesdropped on the Germans, another British genius,
just 70 miles away, was demonstrating the future.
His name was Frank Whittle, and he had created
a plane that would transform our world.
May 15th 1941, the test flight of Britain's first jet.
At 7.45pm, the Gloster E28
flew low and fast over Cranwell Airfield at 370 miles per hour.
The Air Ministry were so uninterested,
they hadn't even bothered to send a photographer.
Luckily, an amateur cameraman captured it on film.
It come right close up to us and ran down the ground
just like a partridge and took off up in the air
and then disappeared in the clouds.
I downed tools and ran in the house to tell everybody
I'd seen an aeroplane without a propeller.
Course, nobody believed me!
The inventor, Frank Whittle, was a brilliant engineer and RAF pilot.
He is a hero of mine.
And if Whittle had been listened to,
planes like this could have been in action against the Luftwaffe
in the Battle of Britain in 1940.
What fascinates me is why nobody believed the eminently believable.
Frank Whittle, a true genius and one of the greatest inventors ever,
not that anyone in officialdom at the time was bright enough to notice.
He thrust Britain into the jet age
and turned the aviation industry on its head.
All with zero encouragement and quite a bit of opposition from the Government.
Some say that the problem lay in Whittle's working-class background,
others in his single-mindedness.
When he was four, Frank was given a model aeroplane
and decided he wanted to become a pilot.
Aged 16, he scraped into the RAF as an apprentice fitter.
But Whittle learned fast.
Soon he was flying aerobatics
at the famous Hendon air display
and volunteering for dangerous
water ditching trials, even though he couldn't swim.
But he wasn't just brave, he was inspired.
When he was only 21,
in 1928, Frank Whittle wrote a thesis in his exercise book entitled
Future Developments In Aircraft Design,
and here's a copy.
In it, he foresaw the whole future of flight.
He could imagine planes flying at 500 miles an hour,
high up in the stratosphere where the air was too thin
for propellers and piston engines to work.
He envisaged that the turbine had the potential
to be the prime mover for jet propulsion.
Whittle's ideas must have seemed like science fiction or fantasy,
but he had done the mathematical calculations to prove them.
He was awarded full marks for his thesis,
with his professor remarking,
"I couldn't quite follow everything you've written, Whittle,
"but I couldn't find anything wrong with it."
I was thrilled to discover
that there's a film about the invention of the jet engine
in which Frank Whittle, the one with the moustache, plays himself.
Ever patented anything?
No, I don't know a thing about it.
I'll tell you what, let's rough out a specification now.
What kind, what do we do?
Well, you make a rather better sketch,
I'll get on with the clever bit, the writing.
OK.
In 1930, still only 22 years old,
Whittle took out this patent for a jet turbine -
a design so simple and so elegant that it takes my breath away.
The injection and burning of fuel heats and expands the air
and gives it enough energy
to drive a turbine...
Whittle's idea was to build an engine with only one moving part
instead of the hundreds of moving parts in conventional piston engines.
This is the legendary Rolls-Royce Merlin engine
that powered the Spitfires and Hurricanes in the Battle of Britain.
Magnificent, yes,
but inefficient and at the limit of what pistons and propellers can do.
Whittle's jet engine had no propeller,
or pistons.
It drove the plane through the air by thrust alone.
It could go higher and faster.
It still has enough energy to give a high-velocity propelling jet.
The Air Ministry was happy with conventional engine technology,
so when Whittle's patent lapsed in 1935,
they wouldn't even pay the 5 to renew it.
But if the British Government weren't interested, other people were.
Whittle's patent quickly found its way into Nazi Germany,
where a young engineer called Hans von Ohain
set about developing his own turbine jet
at the state-of-the-art Heinkel factory in Warnemunde on the Baltic coast.
It would be a race now.
Heinkel and von Ohain versus Whittle and Power Jets Limited,
set up with private backing in a disused foundry in Coventry.
Whittle ran the first engine test in April '37...
..five months ahead of von Ohain.
But who would fly the first plane?
Answer - Hans von Ohain and the Germans on 27th August 1939
with the Heinkel 178.
But the plane was a dead end.
It could fly for only six minutes
and the engine would have to be completely rebuilt
after only a few flights.
Frank Whittle's engine was a triumph from the start.
And here it is, the first Whittle production jet engine
fitted to the Gloster Meteor.
The air comes in the intake here, and it accelerates the air
and then comes through into these combustion chambers
and the fuel is ignited
and goes down into the turbine chamber,
and the turbine accelerates the air at high jet speed out of the back
and that's what provides the thrust to drive the aeroplane forwards.
Now let's start her up.
The Air Ministry was interested at last, and so was Rolls-Royce.
By July 1944,
Whittle-designed jet engines would be powering RAF Meteor fighters,
defending London against the doodlebug,
the V1 flying bomb.
This is what Frank Whittle had in mind when he wrote that thesis.
A plane that can fly 50,000 feet high at 620 miles an hour.
Sitting here as I am now,
I'm literally less than half a metre from two jets...
..and the...
extraordinary force of acceleration you get from it
presses you right back into your seat.
Remember, there's only one moving part.
He's an absolute genius, Whittle.
1944 was a crucial year in the war.
The Allies were set to launch one of the greatest invasions
in the history of the world.
Alan Turing's code-breakers had continued to crack the German codes,
reading secret messages
and providing reassurance that D-Day would come as a surprise to Hitler.
The invasion would be a success,
but the casualties were appalling.
But help was at hand for the injured.
The story of the discovery of penicillin has passed into legend,
but like most legends, the truth is very different.
I'm a biologist and I'm fascinated
by Alexander Fleming and his discovery of penicillin.
This is St Mary's Hospital near Paddington Station in London.
Fleming came back here
after serving as a doctor in the First World War,
determined to find a way to fight infectious diseases.
There is a real story to be told here.
In September 1928, a mould spore came into this room,
nobody knows from where - maybe through the window, maybe through the door,
maybe somebody walked it up on their shoes.
But wherever it came from, it settled on a glass plate
like this one.
A glass dish that had been left unwashed
and which contained jelly and nutrients.
Alexander Fleming was a great scientist
but he wasn't the tidiest of men
and he had left some of these plates lying around
when he went on holiday.
When Fleming came back,
there were a lot of staphylococcus bacteria growing on the plate.
That was normal, they are found all over the place.
But what wasn't normal was that where this unknown mould was growing,
he noticed it had stopped the growth of the bacteria around it.
And what Fleming thought
was that maybe this mould is making a substance that kills the bacteria.
This was going to change the course of history.
This was where the era of antibiotics began.
So what was the genius of Alexander Fleming?
Well, partly it's as Pasteur said - "Chance favours the prepared mind."
Fleming's mind had been prepared during the First World War.
It had been prepared seeing people dying of infections.
So during the 1920s,
Alexander Fleming had been looking for ways
to inhibit the growth of bacteria.
And when chance brought that mould spore onto his plate
his mind was already prepared to think about its significance
and to see where it might lead.
The green mould growing on that plate was penicillin.
And what Fleming wanted to do was to see whether it was really making a substance
that would kill bacteria that infected human beings.
He filtered off the liquid in which the mould had been growing
and then used it to treat a wide variety of bacteria
that infected human beings,
and what he showed was that the filtered liquid
could kill many of these bacteria.
It could kill the bacteria that caused pneumonia, diphtheria,
syphilis, gonorrhoea.
So what he had in his hands
was a possible brand-new way of treating these deadly diseases.
But although penicillin looked like it might be a magic bullet,
Fleming couldn't produce enough of it to test on animals, let alone humans.
And his laboratory experiments suggested
it wouldn't work in living systems anyway.
So Fleming sent samples of it to various labs around the world,
and he moved on to other research.
And there the story of penicillin rested, for more than ten years.
It took an Australian, Howard Florey,
to take up penicillin research again and crack the problem of production.
This is where, in a lab in wartime Britain,
with all its shortages and rationing,
Florey and his colleagues managed to do what Fleming could not -
grow penicillin in enough quantity
and extract it for live testing.
When they had enough penicillin, they could test it on mice.
They took eight mice and infected them with bacteria.
Four they gave penicillin and four they did not.
Within a day, the four that did not get penicillin were dead.
The four that got penicillin were perfectly alive
and running around their cages.
Penicillin worked in mice, and if it worked in mice,
it probably would work in humans.
But a human is 3,000 times heavier than a mouse,
and that's how much more penicillin they needed before they could treat a human.
They grew it in hospital bedpans, and when they ran out of them,
in ceramic pots.
This is the Radcliffe Infirmary.
This hospital is closed now,
but it was the place where Florey and his colleagues first tested penicillin
on a human patient in the hope of curing him.
There was a policeman,
Albert Alexander.
He'd scratched his face with a rose thorn and it had become infected.
It was a terrible infection.
It was eating away at his face.
He had already lost an eye.
Florey and his colleagues had just enough penicillin to start treating him.
At first, the penicillin really helped.
But then they ran out.
They tried extracting it from his urine,
purifying it and then giving it back to him.
But there wasn't enough.
After five days, he began to relapse,
he got worse, he went on to die.
But the proof of principle had been established.
Penicillin had helped him, and if they could simply make more,
then they had a wonder drug on their hands.
But it was 1941, the Blitz was raging
in London and the great industrial cities of Britain,
and mass production of a new and untried drug was a low priority
for British drug companies.
So Florey and his colleagues took penicillin to America
where they found a can-do attitude as well as the money.
NEWSREEL: Through mass production methods, American is increasing
its output of penicillin, a new drug that affects...
And so it was that by D-Day,
6th June 1944,
there was enough penicillin
to treat every Allied soldier
wounded in the invasion of Normandy and the drive to Berlin.
Like many great discoveries,
penicillin was the work of many, not just one.
The same is true of one of the greatest discoveries in physics -
how to split the atom.
It took three generations of British scientists to crack this problem,
and when they did, it led to the creation of the bombs
that helped end the war but also gave mankind a new and terrifying power.
STEPHEN HAWKING: August, 1945.
The Allied bombs on Hiroshima and Nagasaki brought the Second World
War, at last, towards its end.
The atomic bomb was the culmination
of some of the most important discoveries in science,
the brilliant insights and experiments which laid bare
the structure of the atom.
It is a story which owes much to three generations
of British scientists
at the Cavendish Laboratory in Cambridge.
In 1899, JJ Thomson discovered the electron.
21 years later,
his student Ernest Rutherford identified the proton.
In 1932, Rutherford handed the torch down to James Chadwick,
who identified the neutron.
And in the same year, Cockcroft and Walton built a linear accelerator
and split the atomic nucleus
which their forbears had taken 33 years to put together.
The achievements of all these men are immense.
But many physicists reserve a special admiration
for the work of a man whose name is less well known.
Paul Dirac.
He uncovered one of the great secrets of the universe.
KATHY SYKES: Now, Paul Dirac isn't exactly a household name,
but I think he should be.
Dirac may not sound British, but British he was,
and a physicist's physicist.
He was obsessed by beauty, simplicity and mathematics.
He once said that when God created the world,
he used beautiful mathematics.
Now, when he said, "God", he probably meant Nature.
He was a confirmed atheist.
Dirac was certainly a most unusual man.
He once said, "I never knew love or affection as a child,"
and there are many stories and anecdotes about his strangeness.
Dirac was once having a serious argument with his wife
and she eventually said, "And what would you do if I left you?"
He thought for a while and then he said,
"I'd say, "Goodbye, dear.""
People have suggested he might have been autistic.
If he was, perhaps it helped with the clarity
and concentration he brought to physics.
Dirac worked here at Cambridge at the Cavendish Laboratory,
alongside nuclear physicists like Rutherford and Chadwick.
And what he did transformed the work of many physicists to follow.
In 1928, Paul Dirac pulled off
one of the greatest mathematical feats in the history of science.
The Dirac equation.
Think of this less as an equation
and more as a key to understanding the innermost workings
of the universe.
Dirac had worked out what electrons do,
and it looks like this.
This equation brings together two of the great theories in physics -
quantum mechanics, which describes the world of the very small,
things on the atomic scale,
and also Einstein's special theory of relativity,
which describes the world of the very fast,
things travelling close to the speed of light.
This equation won Dirac a Nobel Prize in 1933.
To begin with, he didn't want it because he hated publicity.
But the story goes that Ernest Rutherford,
the great atomic scientist who'd won one in 1908,
persuaded Dirac that the publicity would be much worse
if he turned the prize down.
So he agreed.
The Dirac equation also included a prediction of something bizarre
that had never even been observed,
so no-one believed or knew it existed.
But Dirac's mathematics said it had to exist,
and that crazy something was antimatter.
Scientists believe that when the universe was created,
the big bang made almost as much antimatter as it did matter.
The world as we know it is made of matter,
so where did all the antimatter go?
It's one of the great unanswered questions of science.
If you could get some antimatter
and were to bring it together with ordinary matter,
a lot of energy would be released.
Just as well, then, that the scientists at CERN
have only been able to make ten billionth of a gram in 30 years.
Paul Dirac was one of the greatest nuclear theoretical physicists
since Isaac Newton.
His equation governs most of physics
and the whole of chemistry.
If he could have patented it, he would have been very rich.
Every television set and computer would have paid him royalties.
PAUL NURSE: In 1945, Alexander Fleming and Howard Florey,
together with Florey's colleague Ernst Chain,
shared the Nobel Prize for their discovery of penicillin.
JAMES DYSON: Frank Whittle went to live in the United States,
where he became friends
with his old German rival, Hans von Ohain.
Many years later, von Ohain remarked
that if officials had backed Whittle, World War Two might
never have happened.
Hitler would have doubted the Luftwaffe's ability to win.
JIM AL-KHALILI: After the war,
Britain's radar pioneer went to live in Canada.
In the 1960s, the then elderly Watson-Watt
was stopped by a policeman with a radar gun and given a ticket.
Watson-Watt said to the policeman,
"If I'd known what you were going to do with it,
"I'd never have invented it."
RICHARD DAWKINS: And what of Alan Turing?
Soon after the war, he went to Manchester University,
where he pioneered the development of computer theory and programming
until his mysterious death in 1954.
Was the explanation suicide, accident, or assassination?
Surely by far the most plausible
is the official suicide verdict of the coroner.
Turing had every reason to be unhappy.
In 1952,
he had been convicted of homosexual behaviour.
He'd been offered a choice between prison and chemical castration
by hormone injections which caused his breasts to grow.
No wonder he was depressed.
Whatever the truth, Turing's death at the age of only 41
was surely one of the great tragedies in the history of science.
If anybody could be said to have invented the future,
it was Alan Turing,
but he didn't live to see what he had done.
Next time...
For all the achievements of those who had gone before,
two big questions remained.
How did the universe begin?
And what is the secret of life?
Why are you so obsessed with God?
Well, um...