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As we gazed up at the heavens,
we asked where we had come from,

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how all the stars were created,
how all the elements were made,

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00:00:32,997 --> 00:00:35,388
even how the universe itself had begun.

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00:00:35,423 --> 00:00:40,265
One of mankind's greatest
achievements is that we've
answered these questions.

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What is truly remarkable
is that this understanding has come

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00:00:45,707 --> 00:00:49,272
through the study of the smallest
building blocks of matter - atoms.

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As we peered inwards, we realised
we could explain what we saw
when we peered outwards.

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The atom has helped us solve
the greatest mysteries of existence.

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Everything in the world we see is
made out of tiny objects called atoms

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and yet
we only proved their existence
at the beginning of the 20th century.

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The first shock was to discover
how small they were,

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less than
a millionth of a millimetre across,

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there are trillions
in a single grain of sand.

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Amazingly, we now have
a pretty good idea of the number
of atoms in the known universe.

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Now, given
the vastness of the universe
and the minuteness of the atom,

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it's not surprising that this
is a mind-numbingly huge number,

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it's one
followed by over 70 zeros,

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that's a trillion,
trillion, trillion,
trillion, trillion, trillion atoms.

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We don't only know the raw number
of atoms in the cosmos

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we also know that they come
in 92 different flavours.

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These are called the elements
and you'll recognise many of them

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as familiar parts
of the world around us.

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Oxygen, iron, carbon,
tin, gold and so on.

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Everything in the universe,
the stars, the planets,
the mountains,

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the seas, the animals, you and me,
we're all made of these atoms
or combinations of them.

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It's an astonishing human achievement
that we now know,

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not only how many atoms
there are in the universe

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and how many different types there
are, but why they exist at all.

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We can now explain how every one of
those trillion, trillion, trillion,

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trillion, trillion, trillion atoms
was created.

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It turns out that the answer
to the mystery of creation itself

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lies within the heart of each
and every atom in the universe.

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The story of how we came
to understand creation itself

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started over 100 years ago

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in a small laboratory
in south-east Paris.

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GEIGER COUNTER CLICKS RAPIDLY

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This piece of paper
is a remarkable artefact.

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It's from the notebook of the woman
who first studied radioactivity,
the chemist Marie Curie.

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It's incredible, 100 years later
and this piece of paper is still
spitting out radioactive particles.

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The photograph on the left
shows the concentration
of the radioactivity,

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you can actually see
Marie Curie's thumbprints on it

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but what's really incredible
is the sheer power,

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the energy given off by radioactivity
that this piece of paper

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is still spitting out these particles
100 years later.

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Still stuck to the paper are
tiny but intensely radioactive
particles of a substance

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that Marie Curie discovered in 1898,

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a substance she called radium.

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It was a sensational discovery
for one primary reason.

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Though radium looks like
an unremarkable grey metal,

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it contradicted
all the then-known laws of science.

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Because radium pumps out
invisible yet powerful rays of energy

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which could fog sealed photographic
paper and burn human flesh.

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They're a little like radio waves
which is why
Curie called radium radioactive

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but the waves were millions of times
more powerful than any radio wave
previously encountered.

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Also,
radium appeared to contain within it
an inexhaustible store of energy,

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Curie worked out that
a gram of radium,
a piece much smaller than a penny

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contains more energy
than 100 tons of coal.

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By the turn of the century,
the French public and the tabloid
press were fascinated by radium

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and, rather touchingly
though no-one had a clue
was radioactivity really was,

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everyone assumed it must
be wholesome and healthy.

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When radium was first discovered,
they found all sorts of weird and
wonderful commercial uses for it.

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Here is the Radium bath products,
there's the Radium Eau de Cologne,

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Atomic Perfume and Radium Face Cream
apparently enhancing beauty
through healthy skin.

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There's even the Radium
razor blade, I'm not quite sure
how that's supposed to work.

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Ah, the good old days, clearly
when ignorance really was bliss.

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Whatever the public made of it,
to the scientific community

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radioactivity was just about
the most exciting thing possible.

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The brightest minds of a generation
clamoured to study it

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and the price of radium,
it's most potent source,

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soared to thousands of pounds
per ounce and radioactivity
didn't disappoint.

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In 1919, it produced its greatest
revelation yet,

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a revelation that would ultimately
lead to a fundamental understanding
of the atomic world.

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The revelation was that radioactivity
allowed humanity to fulfil
an age-old dream...

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to become alchemists.

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Alchemy, the power to change
base metals into gold,

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the quest for the so-called
Philosopher's Stone

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which has the magical ability
to transmute one substance
into another,

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has been an obsession for centuries.

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It conjures up wonderful tales of
sorcery and wizardry, as anyone who's
read Harry Potter knows very well.

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The power and wealth that would
surely come to anyone who mastered
alchemy seduced many great scientists

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and thinkers like Isaac Newton,
Robert Boyle and John Locke.

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All of them tried to change
one element into another

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and all of them failed.

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Then in 1919, the secret of alchemy,

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the mystery of
the Philosopher's Stone
was finally revealed,

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not in a wizard's den
but in the physics department
at Manchester University.

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The world's first true alchemist
was Ernest Rutherford.

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A loud, straight-talking
New Zealander,

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Rutherford had come to dominate
the study of radioactivity.

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He had wonderful intuition and was
fearlessly prepared to challenge

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conventional wisdom and alchemy
would require Ernest Rutherford

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to follow his intuition
deep into the unknown.

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The discovery was almost accidental.

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It began when one of
Rutherford's students noticed that

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when radioactive materials like
radium were placed inside a sealed
container of ordinary air,

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mysteriously, small amounts of
the gas hydrogen begin to appear.

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Now this was bizarre. Ordinary air
contains virtually no hydrogen

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and yet in the presence
of radioactivity
it was appearing out of nowhere.

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This was precisely
the kind of problem that Rutherford,

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now at the height of his powers
as an experimental physicist, loved,
and he flung himself at it.

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He began by isolating
all the different gases

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that make up the air we breathe,
nitrogen, oxygen, water vapour
and carbon dioxide

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and studied how each of them behaved
in the presence of radioactivity.

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And then...eureka!

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Rutherford realised
that in the presence of
powerful radioactive rays,

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the gas nitrogen, which makes up
about 80% of the air we breathe,

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changes into two new substances,
the gases oxygen and hydrogen.

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Then and there
Rutherford had transmuted
one element into two others.

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He'd become an alchemist and radium,
with its powerful radioactivity,
was the Philosopher's Stone.

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The press hailed Rutherford
as the first alchemist,
but in fact that was the least of it.

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What alchemy had shown him was
the inside, not just of the atom,

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but of the strange object
at its centre,

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its tiny beating heart, the nucleus.

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To get a sense of this achievement,
remember Rutherford
and his contemporaries at Cambridge

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had only a sketchy idea of
what an atom was but they did have
an idea of its size.

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And it's mind-numbingly tiny,
one tenth of a millionth
of a millimetre across.

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Let me put it another way, there are
more atoms in a single glass of water

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than there are glasses of water
in all the oceans of the world.

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And Rutherford now also knew
that the atom had structure,

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that within the atom
there was a sub-atomic world.

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He pictured each atom
like a tiny solar system.

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At its centre, 100,000 times smaller
than the atom itself

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was an object
which Rutherford called the nucleus.

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Orbiting this, like planets,
were the electrons

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but what on earth WAS the nucleus?

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Rutherford was convinced that
alchemy had shown him the answer.

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To understand how Rutherford did this
we have to get inside his head
to think like he did.

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Rutherford had fantastic intuition
coupled with an intensely
practical approach to science

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00:12:03,612 --> 00:12:07,582
so he hated ideas that relied
on complicated mathematics.

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When it came to the atomic nucleus,
Rutherford looked for
the simplest idea that worked

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and what worked was to imagine
that the nucleus is made of tiny,
rigid spheres, like snooker balls.

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Using this incredibly simple image,
Rutherford could construct
all the elements in the universe.

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He could explain how the huge variety
of different atoms are made
of the same basic components.

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So here's how it works.

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Hydrogen, which is the simplest
element, consists of just one sphere

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which Rutherford called a proton,
which is the Greek word for "first".

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All the other elements are made by
adding more protons to the nucleus.
It's as simple as that.

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So helium,
which is the second lightest element,

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comprises of two protons,
lithium has three.

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00:13:00,755 --> 00:13:04,596
Carbon, which is the element
that's the basis of all life,

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has six protons.

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00:13:05,837 --> 00:13:08,483
The oxygen that we breathe
has eight

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and uranium, which is the heaviest
naturally-occurring element,

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has 92 protons.

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00:13:15,121 --> 00:13:18,526
This was Rutherford's
inspirational idea,

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that each element is defined by
the number of protons in its nucleus.

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It's a wonderfully elegant
and simple idea,

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00:13:27,125 --> 00:13:32,646
an idea that explains
how so much of the universe
we see around us is constructed.

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But as scientists often find,
nature is never quite as simple
as it seems at first sight.

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Sure enough, a big problem
emerged with Rutherford's proton.

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A problem which threatened
to derail the whole atom project

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and it was to be
one of Rutherford's own proteges
who was the first to identify it.

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00:13:58,090 --> 00:14:00,540
Francis Aston
was an interesting character.

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00:14:00,575 --> 00:14:06,538
As a young man he enjoyed
the adventurous outdoors
and was into skiing and motor racing

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00:14:06,573 --> 00:14:11,825
and apparently in about 1909
he discovered surfing
off Waikiki Beach in Hawaii.

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00:14:11,860 --> 00:14:16,661
But he soon realised the call
of the physics laboratory was greater
than the call of the waves

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and it was while at Cambridge
that he invented
an incredible piece of equipment.

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00:14:21,383 --> 00:14:27,186
That's now housed here in this rather
austere and plain-looking building,
the Cavendish Laboratory.

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00:14:32,746 --> 00:14:36,352
This is
Aston's original spectrograph.

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00:14:36,387 --> 00:14:40,630
It's an amazing piece of equipment
because with it, for the first time,

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00:14:40,665 --> 00:14:43,716
scientists were able
to weigh individual atoms.

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00:14:43,751 --> 00:14:47,758
It's incredible, it looks a bit like
a gun, it's a very strange shape.

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00:14:47,793 --> 00:14:52,554
I guess basically, you'd have
the atoms that you wanted to weigh
in this glass tube

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00:14:52,589 --> 00:14:57,000
and the electrically-charged atoms
would be fired in this direction.

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00:14:57,035 --> 00:15:01,836
Round about here there'd be electric
plates which would bend those atoms.

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00:15:01,871 --> 00:15:06,638
Because the atoms had electric charge
they'd get bent in the electric field

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00:15:06,673 --> 00:15:10,525
down in this direction
and then what we're not seeing here

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00:15:10,560 --> 00:15:15,180
would have been a huge magnetic coil
that would sit around this arm

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00:15:15,215 --> 00:15:19,802
and the magnet would bend those atoms
back up again in this direction.

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00:15:19,837 --> 00:15:24,445
Now round about here at the end
would be a photographic plate,

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00:15:24,480 --> 00:15:27,770
I'm not quite sure if we can see it,
no.

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00:15:27,805 --> 00:15:33,287
But the plate would sit here
and atoms of a particular weight
would be focused in a line

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and so Aston was able to see
individual lines for atoms
of different weights.

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00:15:38,164 --> 00:15:42,491
It was remarkable that round about,
just after the First World War,

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00:15:42,526 --> 00:15:45,692
scientists were finally able
to weigh atoms.

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00:15:48,052 --> 00:15:53,335
Now they could weigh atoms
accurately, they discovered that
there was a fundamental problem

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00:15:53,370 --> 00:15:56,253
with Rutherford's model
of the nucleus.

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00:15:56,288 --> 00:15:59,101
Basically the numbers
didn't quite add up.

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00:15:59,136 --> 00:16:05,198
All the atoms of the known elements,
apart from hydrogen, were
much heavier than they should be.

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00:16:05,233 --> 00:16:11,260
For instance, helium,
with two protons should weigh twice
as much as hydrogen, with just one.

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00:16:11,295 --> 00:16:13,905
In fact it's four times as heavy.

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00:16:13,941 --> 00:16:17,547
Rutherford realised
this could mean just one thing -

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00:16:17,582 --> 00:16:22,985
apart from the proton
there's something else inside
the atomic nucleus. But what?

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00:16:28,747 --> 00:16:32,312
It took 12 years to find the answer.

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00:16:32,347 --> 00:16:36,709
Now, as head of the prestigious
Cavendish Laboratory in Cambridge,

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00:16:36,744 --> 00:16:39,591
Rutherford threw
all his resources into the project.

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00:16:43,912 --> 00:16:48,753
He bullied and cajoled his students
and researchers until one,

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00:16:48,788 --> 00:16:52,513
a northern lad from humble origins
called James Chadwick,

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00:16:52,548 --> 00:16:55,320
hit the nuclear physics
equivalent of gold.

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00:16:55,355 --> 00:17:01,758
Chadwick built this in 1932
and to think that with just
this tiny little piece of equipment

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00:17:01,793 --> 00:17:05,403
he discovered
the missing ingredient of the atom.

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00:17:05,438 --> 00:17:13,002
For me
as a practising nuclear physicist
this really is an amazing device.

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00:17:13,037 --> 00:17:16,340
When I think of the huge accelerators
that are built today

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00:17:16,375 --> 00:17:20,209
to conduct experiments to probe
the nucleus of the atom,

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00:17:20,244 --> 00:17:23,904
it's really awe-inspiring
in its simplicity, really.

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00:17:23,939 --> 00:17:27,531
He put a source of radioactivity
at this end of the tube

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00:17:27,566 --> 00:17:31,852
and the radioactivity then struck
a small target in the middle here

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00:17:31,887 --> 00:17:36,929
and then out of the target
came new particles that sprayed
out of this end here.

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00:17:36,964 --> 00:17:42,736
It's a bit like an atomic gun,
shooting out
Rutherford's missing particles.

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00:17:42,771 --> 00:17:50,654
What Chadwick discovered was that
along with the proton there's another
kind of particle inside the nucleus.

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00:17:50,689 --> 00:17:55,056
It weighs almost exactly the same
as a proton but is much more elusive

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00:17:55,091 --> 00:17:57,942
because it carries
no electrical charge.

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00:17:57,977 --> 00:18:03,538
Technically we say it's electrically
neutral hence its name, the neutron,

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00:18:03,573 --> 00:18:07,179
and it immediately solved
the problem of the weight of atoms.

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00:18:07,214 --> 00:18:10,705
So, helium
is four times as heavy as hydrogen

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00:18:10,740 --> 00:18:15,962
because along with its two protons
it contains two neutrons

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00:18:15,997 --> 00:18:21,184
and oxygen has eight neutrons
along with its eight protons,

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00:18:21,219 --> 00:18:25,543
making it 16 times
as heavy as hydrogen.

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00:18:25,578 --> 00:18:29,831
So in 1932,
the atomic family was complete.

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00:18:29,866 --> 00:18:36,228
Scientists announced that
every atom in the universe is made
of just three basic components -

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00:18:36,263 --> 00:18:40,408
electrons,
tiny particles orbiting a nucleus

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00:18:40,443 --> 00:18:44,552
which in turn
is made of protons and neutrons.

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WALTZ PLAYS

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# Neutron, neutron... #

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00:18:52,396 --> 00:18:57,957
Over Christmas 1932,
physicists at the other great centre
of atomic physics,

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00:18:57,992 --> 00:19:02,896
the Niels Bohr Institute
in Copenhagen celebrated
the neutron's discovery

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00:19:02,931 --> 00:19:07,799
and the completion
of the nuclear trinity
by writing a musical about it.

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00:19:07,834 --> 00:19:11,041
# That which experiment has found

219
00:19:11,076 --> 00:19:15,087
# For theory had no part in

220
00:19:15,122 --> 00:19:18,564
# Is always reckoned more than sound

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00:19:18,599 --> 00:19:22,462
# To put your mind and heart in

222
00:19:22,497 --> 00:19:26,327
# Good luck, you heavyweight Ersatz

223
00:19:26,362 --> 00:19:30,325
# We welcome you with pleasure

224
00:19:30,360 --> 00:19:34,344
# But passion ever spins our plot

225
00:19:34,379 --> 00:19:38,329
# And Gretchen is my treasure. #

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00:19:39,851 --> 00:19:43,452
Some of the great names in
physics took part in this musical.

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00:19:43,487 --> 00:19:47,819
Their excitement
was primarily due to one thing.

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00:19:47,854 --> 00:19:52,376
They knew they stood at the threshold
of an entirely new kind of science

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00:19:52,411 --> 00:19:57,457
with entirely new rules,
what we now call nuclear physics.

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00:20:01,378 --> 00:20:04,185
The first challenge
for nuclear physics was this.

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00:20:04,220 --> 00:20:08,740
Although physicists now knew
what the tiny nucleus was made of

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they couldn't explain
how it all held together.

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00:20:11,622 --> 00:20:16,349
In fact it was worse than that,
the existing laws of physics

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predicted that every atomic nucleus
should self-destruct instantly.

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# Eternal neutrality
pulls us alo-o-o-ng. #

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00:20:29,108 --> 00:20:35,469
The main problem was this.
All protons, the key ingredient
of the atomic nucleus

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have positive electric charge
and things with the same charge
repel each other

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00:20:42,028 --> 00:20:44,234
just like these magnets. Look.

239
00:20:51,355 --> 00:20:55,997
So just like these magnets,
if two protons get close together

240
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they should then just fly apart

241
00:20:58,438 --> 00:21:02,524
but weirdly,
inside the atomic nucleus they don't.

242
00:21:02,559 --> 00:21:07,360
Dozens of protons can stick
together alongside each other.
So what sticks them together?

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00:21:07,395 --> 00:21:10,447
What stops the protons
from flying apart?

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The answer was big news,
it was nothing less than
an entirely new force of nature.

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00:21:16,998 --> 00:21:21,643
For centuries humans had only ever
encountered two natural forces,

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gravity which pulls us down
to the Earth and electromagnetism.

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But now, hidden inside
the atomic nucleus
was something completely new,

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it was called
the strong nuclear force

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and the easiest way to imagine it

250
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is with some Velcro.

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If I put Velcro around these magnets,
they start to behave
slightly differently.

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00:21:46,369 --> 00:21:48,540
At first they repel
each other just as before

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but when they get close enough
the Velcro kicks in and they stick.

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The effect is very short range
but very, very strong

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and it's exactly the same
with protons.

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The strong nuclear force explains
what holds the nucleus together.

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The strong nuclear force works
between all protons and neutrons

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but what is truly surprising about it
is its strength.

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It's by far the most powerful force
in the universe...

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more than a trillion, trillion,
trillion times stronger than gravity.

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Think about it this way, if I was
pulled down the earth, not by gravity
but by the strong nuclear force

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then I'd weigh trillions of times
more than I actually do, in fact I'd
weigh more than the entire galaxy.

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But the reason
I don't weigh that much
is because the strong nuclear force

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is only felt down at a distance
of a trillionth of a millimetre.

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With the strong nuclear force,
humans finally began to get a glimpse

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of what was actually going on
inside the atomic nucleus.

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Roughly speaking, all nuclear
behaviour is down to a balance

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between the strong nuclear force
squashing the protons and neutrons
together

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and the electric charge
on the protons forcing them apart.

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Physicists realised that picturing
the nucleus as a battlefield

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between different elemental forces
solved one of the oldest mysteries
of all time.

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It's this.
A question that humans have asked
ever since the dawn of time

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is, how does the sun shine?

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Now sunlight is the source of
all life on Earth but how is it made?

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It's all to do with the forces
inside the atoms that make up most of
the sun - hydrogen.

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This is how it works.

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The nucleus of a single atom of
hydrogen consists of just a proton

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and every now and again inside
the high-pressure, high-temperature
cauldron of the sun,

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this proton can get squeezed up close
to another and bang!

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The strong nuclear force kicks in
and fuses them together.

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CYMBALS CRASH

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Now this is a process that
eventually leads to the creation
of a helium atom

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and it's accompanied
by the release of energy
as a burst of light and heat.

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It's a bit like
slamming two cymbals together
and releasing a burst of sound.

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Hydrogen fusing into helium
and the energy released

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is what we see and feel as sunshine.

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This process of
two hydrogen nuclei slamming together

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and releasing energy
became known as nuclear fusion.

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The turmoil between the strong
nuclear and electromagnetic forces

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as they strive
to dominate the nucleus
does more than just power the sun.

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It's at the heart of everything

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but in the late 1930s
before people figured out that story,

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nuclear physics did something
much closer to home.

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In no uncertain terms,
it redefined the history of mankind
right here on Earth

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and led to one of our darkest hours

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and that story began
with the study of the humble neutron.

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In the years immediately following
its discovery the neutron
became the focus of atomic research

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in laboratories across Europe
and the reason for the excitement
was this.

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See, the neutron is the stealth
bomber of the atomic world because
unlike the other particles

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that make up the atom,
the proton and the electron,

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the neutron is, as its name suggests,
electrically neutral

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so it can fly
undetected and undeflected
into the very heart of the atom

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and collide with the nucleus.

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Now physicists knew that these
collisions would be spectacular
because by atomic standards

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the neutron is heavy
so when it collides with
the nucleus, it deals a mighty blow.

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It's a bit like the Moon
smashing into the Earth.

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Now physicists in the 1930s
knew that this held up all sorts
of tantalising possibilities.

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Such collisions might chip bits off
the nucleus and create new elements.

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They might -
and this is the Holy Grail -

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even create new radioactive elements
like Marie Curie's radium

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which was the source
of unlimited energy.

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In their excitement
about this new science,
physicists in labs across Europe

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fired neutrons into every element
they could find.

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In a laboratory in the Kaiser Wilhelm
Institute in Berlin,

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a chemist called Otto Hahn
finally got round to firing neutrons

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at the last, heaviest element
in the periodic table,

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the metal uranium.

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This is some of the equipment
that he used in the late 1930s.

319
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So, what they would have would be
a source of neutrons sitting here
surrounded by a block of paraffin wax

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that would slow down the neutrons so
they'd be more likely to be absorbed
by the uranium sitting on the side.

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This electronic equipment was used
to detect the particles coming out
from these radioactive elements.

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What Otto Hahn tried to do was
to analyse chemically

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the new elements being produced
from the reaction.

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What he found was what appeared to be
Marie Curie's radium being produced

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but when he tried to isolate it
he didn't find any at all.

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00:28:08,504 --> 00:28:12,225
Instead it seemed that what was
being produced was the element barium

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which was much lighter than uranium.

328
00:28:14,901 --> 00:28:16,470
How could barium be produced?

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00:28:16,505 --> 00:28:19,467
It was a puzzle,
he simply couldn't explain it.

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Nevertheless, Hahn meticulously
catalogued his results.

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Hahn was a chemist not a physicist
but, even so, he knew that
according to all laws of science

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there was no way barium would be
coming out of his experiment.

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It was simply
too different from uranium,

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the only person
who Hahn thought might be able
to explain what was going on

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was his old assistant,
the physicist Lise Meitner.

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But she'd been forced to flee
Nazi Germany a few months earlier

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because she was Jewish so Hahn
sent her his controversial findings.

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Lise Meitner was in Sweden
with her nephew, Otto Frisch

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who was also a nuclear physicist,

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when she received the letter
from Hahn.

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On Christmas Eve 1938
they went for a walk in the woods

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where they discussed long and hard
the results of Hahn's experiment.

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They realised
that the uranium nucleus

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wasn't just having a small piece
chipped off the edge.

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The nucleus was literally splitting
into two equal halves.

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Meitner and Frisch were shocked
beyond belief.

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00:29:38,014 --> 00:29:41,300
The idea that uranium
could literally split into two

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had never been considered remotely
possible but after Hahn's experiment
it was the only explanation.

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00:29:48,011 --> 00:29:54,900
Right then, Meitner and Frisch
realised this had astonishing
and terrifying consequences.

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The huge uranium nucleus
splits into two
because the strong nuclear force

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loses its battle to hold
the nucleus together.

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00:30:03,022 --> 00:30:09,104
The electrical repulsion
then tears the nucleus apart
and the amount of energy released

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would be on a scale
never seen before.

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00:30:18,708 --> 00:30:24,469
The energy released from
a single uranium nucleus would be
enough to move a grain of sand.

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Now this is an incredible
amount of energy

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because a grain of sand itself
contains trillions and trillions
of atoms.

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00:30:30,472 --> 00:30:34,874
It's a bit like
kicking a football at the Moon
and knocking the Moon off its orbit.

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For me, this heralded
the birth of the atomic age.

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What Frisch and Meitner
had discovered was nuclear fission.

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Nuclear fission was the first time
anyone had released

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the enormous forces
inside the nucleus artificially.

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00:31:02,401 --> 00:31:07,804
Uranium gave mankind the means
to tap into the vast, seething energy

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inside the nucleus
and turn it to its own uses.

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00:31:14,726 --> 00:31:19,648
The timing of the discovery -
it coincided with the beginning
of the Second World War -

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meant that Allied scientists
under Robert Oppenheimer
worked day and night

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00:31:24,809 --> 00:31:30,971
to figure out how nuclear fission
could be exploited
as a weapon of mass destruction

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00:31:31,006 --> 00:31:36,054
and the final manifestation of this
research came in 1945

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over Hiroshima and Nagasaki.

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00:31:38,530 --> 00:31:40,495
ATOM BOMB BLASTS

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The atom bomb changed everything.

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The excitement of
pre-war scientific research,

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the days when physicists sang songs
about their discoveries, were over.

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Robert Oppenheimer summed up
the grim mood with these words.

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"The physicists have known sin
and this is a knowledge
which they cannot lose."

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The terrible irony
of the atomic bomb is that
because of the scientists' sin,

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because of that knowledge
that cannot be lost, something
of great significance did emerge.

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00:32:41,871 --> 00:32:45,238
Something that would ultimately
reveal the full story

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of the 14 billion years
of the entire universe.

379
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The war had caused
a massive two billion dollars
to be poured into nuclear research.

380
00:33:02,558 --> 00:33:07,404
People now knew an astonishing amount
about the atom and its nucleus.

381
00:33:11,126 --> 00:33:14,651
Specifically,
scientists had detailed measurements

382
00:33:14,686 --> 00:33:19,294
of how stable or unstable
different atomic nuclei were.

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00:33:19,329 --> 00:33:27,011
That stability was a direct result of
the battle between the strong nuclear
force holding the nucleus together

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00:33:27,046 --> 00:33:30,417
and the electromagnetic force
pushing it apart.

385
00:33:30,452 --> 00:33:34,419
In some atoms, the balance
tipped towards the strong force

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00:33:34,454 --> 00:33:39,895
making them very stable
but when the electromagnetic force
had the upper hand

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00:33:39,930 --> 00:33:41,621
they were inherently unstable.

388
00:33:41,656 --> 00:33:47,019
By the late '40s, scientists
began to investigate the implications

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00:33:47,054 --> 00:33:50,505
of the way
nuclear stability of atoms varies.

390
00:33:50,540 --> 00:33:57,222
They noticed one very strange fact
about the nuclear stability
of one particular atom.

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IRON CLANGS

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00:34:04,105 --> 00:34:09,306
Of all the 92 different elements,
of the 92 different types of atoms

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00:34:09,341 --> 00:34:11,711
that make up
the universe around us,

394
00:34:11,746 --> 00:34:17,028
gases like hydrogen and oxygen,
solids like carbon and silicon,

395
00:34:17,063 --> 00:34:21,189
metals like gold and silver,
one is special...

396
00:34:21,224 --> 00:34:22,191
iron.

397
00:34:28,993 --> 00:34:31,038
So what makes iron so special?

398
00:34:31,073 --> 00:34:35,079
It stems from the unique structure
of its nucleus.

399
00:34:35,114 --> 00:34:41,197
The 26 protons
along with the neutrons
combine in a very special way

400
00:34:41,232 --> 00:34:43,277
to make iron incredibly stable.

401
00:34:44,318 --> 00:34:47,604
For some reason,
nature has decreed this as the number

402
00:34:47,639 --> 00:34:53,600
that allows the strong force
and the electromagnetic force
to balance each other perfectly.

403
00:34:56,042 --> 00:35:00,482
It makes iron the most stable element
in the universe.

404
00:35:01,643 --> 00:35:05,569
Now we can understand
why fusion occurs.

405
00:35:05,604 --> 00:35:10,847
Lighter atoms can combine together
to become more iron-like

406
00:35:10,882 --> 00:35:14,292
and fission is the opposite process,

407
00:35:14,327 --> 00:35:20,890
atoms heavier than iron
can split apart into lighter,
more iron-like pieces.

408
00:35:20,924 --> 00:35:24,856
So all elements seek
the stability of iron

409
00:35:24,891 --> 00:35:30,017
and that fact underpins
the whole history of the cosmos.

410
00:35:30,052 --> 00:35:36,175
The best way to understand this
is to imagine the relative stability
of atoms as a couple of graphs.

411
00:35:36,210 --> 00:35:38,101
Here's what they show.

412
00:35:38,136 --> 00:35:41,263
The very lightest elements,
hydrogen and helium

413
00:35:41,298 --> 00:35:45,299
are not quite as stable as they could
be, they'd like to be something else,

414
00:35:45,334 --> 00:35:47,103
something even more stable.

415
00:35:47,138 --> 00:35:50,740
Similarly, the heaviest elements
like uranium and polonium

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00:35:50,775 --> 00:35:53,826
are actually unstable,
in fact they're so unstable

417
00:35:53,861 --> 00:35:57,182
that they fall to pieces
naturally through radioactivity.

418
00:35:57,217 --> 00:36:00,503
And here, in the middle
are the most stable atoms of all,

419
00:36:00,538 --> 00:36:03,184
nickel, cobalt and iron.

420
00:36:03,219 --> 00:36:05,630
So far, so good.

421
00:36:05,665 --> 00:36:11,748
Now, here's the amazing bit,
this nuclear stability graph
turned out to be uncannily similar

422
00:36:11,783 --> 00:36:17,469
to a different graph altogether
but it was a similarity
that no-one had ever suspected.

423
00:36:17,504 --> 00:36:22,070
That's because data from this other
graph came not from the tiny nucleus

424
00:36:22,105 --> 00:36:25,152
but from as different
an arena as you can imagine...

425
00:36:25,187 --> 00:36:27,917
the vast expanses of space.

426
00:36:27,952 --> 00:36:30,553
This other graph
came from astronomers

427
00:36:30,588 --> 00:36:33,120
who studied
the blazing light from stars

428
00:36:33,155 --> 00:36:36,836
and shows the abundances
of the different types of atoms

429
00:36:36,871 --> 00:36:38,000
in the universe.

430
00:36:38,035 --> 00:36:41,483
By far the most common atom of all
is that of hydrogen

431
00:36:41,518 --> 00:36:47,039
followed closely by helium but
not a great deal of anything else.

432
00:36:47,074 --> 00:36:50,778
Now look at this, it really
is of cosmic significance.

433
00:36:50,813 --> 00:36:54,482
Both graphs, the stability graph
and the abundances graph

434
00:36:54,517 --> 00:36:59,568
show the same strange
but very noticeable peak

435
00:36:59,603 --> 00:37:02,889
The first scientists who spotted this
were blown away.

436
00:37:02,924 --> 00:37:08,047
One graph from the tiny nucleus and
the other from the vastness of space

437
00:37:08,082 --> 00:37:10,332
point to the same magical atom.

438
00:37:10,367 --> 00:37:15,928
The atom that provided the key
to unlocking the secrets
of the entire universe.

439
00:37:15,963 --> 00:37:21,855
Iron, the atom which was the key
to understanding the atomic nucleus,

440
00:37:21,890 --> 00:37:27,537
also turned out to be
one of the most abundant atoms
in the entire universe.

441
00:37:27,572 --> 00:37:33,574
Amazingly the properties of
its nucleus seem to lead directly
to how much of it there is

442
00:37:33,609 --> 00:37:35,575
and it's not just true of iron.

443
00:37:36,897 --> 00:37:42,178
Radium, which is very unstable,
turns out to be incredibly rare.

444
00:37:44,258 --> 00:37:50,500
Aluminium which is relatively stable
turned out to be relatively common.

445
00:37:50,535 --> 00:37:54,518
It's a pattern which appears
right across the list of elements.

446
00:37:54,553 --> 00:37:58,502
The signature of their nuclei
is written in the skies above us...

447
00:38:00,663 --> 00:38:05,906
..and deciphering the meaning of
this connection would require
the greatest minds of a generation.

448
00:38:05,941 --> 00:38:10,605
The first of these was a rebel
and a maverick called Fred Hoyle.

449
00:38:10,640 --> 00:38:15,234
He loved walking the hills
and dales of his native Yorkshire.

450
00:38:15,269 --> 00:38:20,311
Hoyle always spoke his mind
even though it brought him
into conflict with his peers.

451
00:38:20,346 --> 00:38:23,237
He became something
of a scientific pariah.

452
00:38:23,271 --> 00:38:28,114
More than almost any other scientist,
he explored the strange overlap

453
00:38:28,149 --> 00:38:33,320
between the science of the atom
and the science of the cosmos.

454
00:38:33,355 --> 00:38:37,597
Hoyle realised what the graphs
revealed is that the underlying theme

455
00:38:37,632 --> 00:38:40,958
of the universe
was ultimately change.

456
00:38:48,040 --> 00:38:51,887
Everything in the universe
is in a state of flux.

457
00:38:51,922 --> 00:38:58,164
The atoms are trying
to gain or lose protons
in an attempt to become more stable.

458
00:38:58,199 --> 00:39:04,246
What Hoyle and his colleagues did
was to ask
how and where in the cosmos

459
00:39:04,281 --> 00:39:10,407
all this atomic transformation,
all this alchemy, takes place.

460
00:39:10,442 --> 00:39:12,894
Hoyle knew that
in stars like our sun,

461
00:39:12,929 --> 00:39:17,295
hydrogen turns into helium by
a process called nuclear fusion.

462
00:39:17,330 --> 00:39:24,372
But could nuclear fusion
also be the way all the other atoms
in the universe are made?

463
00:39:26,412 --> 00:39:30,459
Fred Hoyle's great insight
was to work out precisely

464
00:39:30,494 --> 00:39:35,416
how the heaviest elements
are created through nuclear fusion.

465
00:39:35,451 --> 00:39:39,143
Hoyle worked out that this process
can only take place

466
00:39:39,178 --> 00:39:45,140
at unimaginably high pressures
and temperatures of
millions of degrees centigrade.

467
00:39:45,175 --> 00:39:51,102
In our universe
there's only one place where
such conditions exist...in stars.

468
00:39:54,343 --> 00:39:57,269
Fred Hoyle's problem
was with the details.

469
00:39:57,304 --> 00:40:04,146
To explain how fusion could create
atoms heavier than helium
was tricky and complicated.

470
00:40:04,182 --> 00:40:09,788
Hoyle had to explain precisely
how in the fierce heat inside stars,

471
00:40:09,823 --> 00:40:12,950
light atoms might fuse
to become heavier ones.

472
00:40:17,190 --> 00:40:18,917
EXPLOSION

473
00:40:18,952 --> 00:40:25,638
In the '40s, Hoyle worked out that
our sun is hot enough to fuse atoms

474
00:40:25,673 --> 00:40:33,597
like oxygen, carbon and nitrogen
but what about heavier atoms
like copper, zinc or iron?

475
00:40:33,632 --> 00:40:37,758
His calculations showed that
they could be made inside stars

476
00:40:37,793 --> 00:40:41,239
but these would have to be
much hotter than our sun

477
00:40:41,274 --> 00:40:43,720
and he knew exactly
where to find them.

478
00:40:45,439 --> 00:40:52,527
These huge, bloated stars
near the end of their lives
were called red giants.

479
00:40:52,562 --> 00:40:58,364
Astronomers had discovered that there
were hundreds of millions of these
monsters throughout the universe.

480
00:40:58,399 --> 00:41:02,744
Fred Hoyle reasoned that
they were hot enough to allow

481
00:41:02,779 --> 00:41:07,087
weightier atoms to be fused
but there was still a problem.

482
00:41:07,122 --> 00:41:10,694
Even the mighty red giants
weren't hot enough

483
00:41:10,729 --> 00:41:15,455
to make the really heavy stuff,
atoms like gold and uranium.

484
00:41:15,490 --> 00:41:20,611
To make these heavier than iron atoms
would mean forcing them
to fuse together,

485
00:41:20,646 --> 00:41:23,897
becoming more and more unstable.

486
00:41:23,932 --> 00:41:27,299
It would require unimaginable
temperatures and pressures.

487
00:41:27,334 --> 00:41:32,941
His only hope was that somewhere
out there in the vastness of space

488
00:41:32,976 --> 00:41:39,098
were things so big and so hot
they made our sun look like
a birthday candle.

489
00:41:45,581 --> 00:41:48,666
And towards the end
of the Second World War,

490
00:41:48,701 --> 00:41:53,628
during a research trip to Southern
California, Fred Hoyle found them.

491
00:41:53,663 --> 00:42:00,230
This is the 100-inch telescope
at the Mount Wilson Observatory
outside Los Angeles.

492
00:42:00,265 --> 00:42:06,948
When it was first built
in 1917, it was without doubt
the largest telescope in the world

493
00:42:06,983 --> 00:42:10,668
and it was while he was here
he met up with the great astronomer,

494
00:42:10,703 --> 00:42:15,076
Walter Baade who told him about
supernovae.

495
00:42:15,111 --> 00:42:18,717
Now these are processes
when massive stars explode

496
00:42:18,752 --> 00:42:22,917
with an incredible intensity
and in a flash of inspiration

497
00:42:22,953 --> 00:42:29,915
Hoyle realised that here, at last,
were the extreme conditions necessary
to produce all the heavy elements.

498
00:42:31,717 --> 00:42:36,757
What Baade was referring to was
an explosion of simply cosmic scale.

499
00:42:39,119 --> 00:42:41,924
BANG!

500
00:42:41,959 --> 00:42:49,081
When the larger stars run out
of hydrogen to fuse into helium,
they come to the end of their lives

501
00:42:49,116 --> 00:42:55,084
and they collapse under
the weight of their own gravity
and then explode outwards.

502
00:43:02,846 --> 00:43:07,767
In a blinding flash of inspiration,
Hoyle and his colleague
William Fowler

503
00:43:07,802 --> 00:43:12,809
realised that supernovae might be
the hottest places in the universe,

504
00:43:12,844 --> 00:43:16,856
hot enough to fuse together
even the heaviest of atoms.

505
00:43:16,891 --> 00:43:22,058
Hoyle and Fowler
had found the furnaces
in which everything was made.

506
00:43:22,093 --> 00:43:29,615
The discovery of how atoms are made
in stars is surely one of
humanity's greatest achievements,

507
00:43:29,650 --> 00:43:32,141
except for one glaring problem.

508
00:43:32,176 --> 00:43:36,503
One that Hoyle could never
explain away and it was this.

509
00:43:36,538 --> 00:43:43,100
Stellar nuclear fusion can explain
how all the elements in the universe
are made...except for two,

510
00:43:43,135 --> 00:43:44,905
two very important ones.

511
00:43:44,940 --> 00:43:49,181
The two simplest elements,
hydrogen and helium.

512
00:43:52,024 --> 00:43:55,950
In the 1940s, using
increasingly accurate equipment,

513
00:43:55,985 --> 00:44:00,026
scientists found that a quarter
of the sun was in fact helium

514
00:44:00,061 --> 00:44:03,592
which was considerably more
than they thought.

515
00:44:03,627 --> 00:44:08,508
They realised that to fuse that
amount of helium would mean the sun

516
00:44:08,543 --> 00:44:13,390
would have to be burning at billions
of degrees but the truth was,

517
00:44:13,424 --> 00:44:16,677
the sun only burns
at 15 million degrees.

518
00:44:16,712 --> 00:44:21,154
The sun just wasn't hot enough
to have made all that helium.

519
00:44:23,474 --> 00:44:26,999
In fact,
it turns out that per cubic metre,

520
00:44:27,034 --> 00:44:31,521
the sun actually generates less heat
than a human being

521
00:44:31,556 --> 00:44:36,717
so I produce more heat than a piece
of the sun the same size as me.

522
00:44:36,752 --> 00:44:40,395
This means that the sun
is just not hot enough

523
00:44:40,430 --> 00:44:44,040
to make all the helium
we know that it contains.

524
00:44:47,161 --> 00:44:52,103
If all the helium wasn't made in
the sun then where did it come from?

525
00:44:52,138 --> 00:44:57,010
And even more crucial
was the question
Hoyle was in denial about.

526
00:44:57,045 --> 00:45:02,688
If all the atoms in the universe
started off as hydrogen,
where did THAT come from?

527
00:45:02,723 --> 00:45:07,934
All that hydrogen and all that helium
needed an explanation.

528
00:45:07,969 --> 00:45:13,575
This problem catalysed
one of the most vicious fights
in post-war science.

529
00:45:13,610 --> 00:45:19,573
That's because it turned
into a much bigger question,
in fact, the ultimate question.

530
00:45:19,608 --> 00:45:26,135
Was the entire universe
created in a single instant
or has it always been there?

531
00:45:28,575 --> 00:45:35,659
Nearly every post-war physicist
was sucked into this controversy
but two men were at its centre.

532
00:45:36,739 --> 00:45:43,942
One was Fred Hoyle,
the other was an eccentric Ukrainian
called George Gamow.

533
00:45:43,977 --> 00:45:49,867
6'4", a practical joker
and a refugee from Stalin's Russia.

534
00:45:49,903 --> 00:45:55,284
Another physicist said of Gamow,
"even when he's wrong,
he's interesting".

535
00:45:55,319 --> 00:46:00,667
Both men would stake their careers on
this mother of all physics battles.

536
00:46:05,868 --> 00:46:11,116
It all began innocently enough.
Gamow had recently
been appointed a professor

537
00:46:11,151 --> 00:46:17,952
at George Washington University and
thought the hydrogen and helium
riddle might be worth exploring.

538
00:46:25,716 --> 00:46:31,923
This was George Gamow's office
at the George Washington University.
It's really pokey!

539
00:46:31,958 --> 00:46:38,720
It was here that Gamow worked on
the problem of why there seemed
to be too much helium gas in the sun

540
00:46:38,755 --> 00:46:42,806
than could be accounted for
from the fusion of hydrogen.

541
00:46:42,841 --> 00:46:46,602
Gamow came up with the crazy idea
that maybe most of this helium

542
00:46:46,637 --> 00:46:49,684
had been around
before the sun was even formed.

543
00:46:51,524 --> 00:46:58,412
This is the moment
it gets controversial and leads us
inexorably into a row over creation.

544
00:46:58,447 --> 00:47:04,808
For Gamow to assert that helium
existed in the universe before
the sun and the stars were formed

545
00:47:04,843 --> 00:47:10,547
he had to come up with another place
that was capable of making helium.

546
00:47:10,582 --> 00:47:16,251
Gamow knew wherever this process was,
it needed to be staggeringly hot,

547
00:47:16,286 --> 00:47:19,071
a searing billion degrees centigrade,

548
00:47:19,106 --> 00:47:21,820
millions of times hotter
than the sun.

549
00:47:21,855 --> 00:47:26,341
At this temperature, matter,
as we know it, is ripped apart.

550
00:47:26,376 --> 00:47:34,018
Hydrogen nuclei move about
manically, constantly colliding,
making helium at a prodigious rate.

551
00:47:34,053 --> 00:47:39,379
But what cosmic event was capable
of reaching such an epic,
terrifying temperature?

552
00:47:42,582 --> 00:47:46,107
To explain this,
he used a speculative theory

553
00:47:46,142 --> 00:47:51,348
that was doing the rounds
at the time that suggested that
the whole universe had been created

554
00:47:51,383 --> 00:47:57,346
in a single cataclysmic explosion
billions of years ago, a theory
that today we call the Big Bang.

555
00:47:58,466 --> 00:48:03,667
For decades astronomers have known
that the galaxies are flying away
from each other

556
00:48:03,702 --> 00:48:08,514
at astonishing speeds.
The universe is getting bigger.

557
00:48:08,549 --> 00:48:13,232
This means that in the past
the universe must have been
much smaller

558
00:48:13,267 --> 00:48:17,531
and in the very, very distant past
the entire universe

559
00:48:17,566 --> 00:48:21,794
must have been a tiny,
almost infinitesimally minute dot.

560
00:48:26,595 --> 00:48:30,683
And the implication of this
is a single moment of creation,

561
00:48:30,718 --> 00:48:36,558
an instant at which all matter,
even time and space, came into being.

562
00:48:40,041 --> 00:48:46,408
In 1945, most scientists were
uncomfortable with this idea
but not Gamow.

563
00:48:46,443 --> 00:48:52,525
He spotted that it might solve
the mystery of the excess helium
in the sun and stars.

564
00:48:52,560 --> 00:48:57,446
Gamow worked out that if
the entire cosmos was squeezed down

565
00:48:57,481 --> 00:49:01,652
to a tiny dot
it would be immensely hot.

566
00:49:01,687 --> 00:49:08,970
In the first few minutes after
the creation the universe would have
been hot enough for hydrogen nuclei

567
00:49:09,005 --> 00:49:13,851
to squeeze together
to make all the excess helium
in the sun and stars.

568
00:49:13,886 --> 00:49:17,850
Now, after those first few minutes
the universe would have expanded

569
00:49:17,885 --> 00:49:22,470
and would have been too cool but
a few minutes were all Gamow needed.

570
00:49:22,505 --> 00:49:27,057
In that time, all the hydrogen
and almost all the helium was made.

571
00:49:27,092 --> 00:49:31,596
That's about 98% of all the atoms
in the universe today

572
00:49:31,631 --> 00:49:36,145
or as Gamow put it,
our universe was cooked in less time

573
00:49:36,180 --> 00:49:40,661
than it takes to cook a dish
of duck and roast potatoes!

574
00:49:40,696 --> 00:49:43,541
BANG!

575
00:49:50,625 --> 00:49:54,907
But by arguing that the Big Bang,
a deeply controversial idea,

576
00:49:54,942 --> 00:49:59,188
had created most of the hydrogen
and helium in the universe

577
00:49:59,223 --> 00:50:03,515
Gamow ignited an enormous row
over creation.

578
00:50:03,550 --> 00:50:07,550
Fred Hoyle soon became the most vocal
of Gamow's critics.

579
00:50:09,031 --> 00:50:12,152
Fred Hoyle hated
the idea of the Big Bang

580
00:50:12,187 --> 00:50:14,797
with every fibre of his being.

581
00:50:14,832 --> 00:50:18,839
You see, as a committed atheist
he objected to the theory

582
00:50:18,874 --> 00:50:23,396
because a single moment of creation
to him smacked of a divine creator.

583
00:50:23,431 --> 00:50:26,602
Gamow hit back saying that
without the Big Bang,

584
00:50:26,637 --> 00:50:32,679
Hoyle couldn't properly explain
why there was so much hydrogen
and helium in the universe.

585
00:50:32,714 --> 00:50:38,200
Both men had their supporters and
the argument between the rival camps

586
00:50:38,235 --> 00:50:42,327
became quite shrill and personal.

587
00:50:42,362 --> 00:50:47,403
Hoyle was deemed as
an old-fashioned, crusty old Brit
by the Big Bang supporters

588
00:50:47,438 --> 00:50:53,343
and Gamow was condemned as a closet
creationist by Hoyle's supporters.

589
00:50:53,378 --> 00:50:59,249
The argument raged in scientific
conferences and in the popular press.

590
00:50:59,284 --> 00:51:03,375
Secretly, each side knew
that they had a compelling argument

591
00:51:03,410 --> 00:51:08,972
but both lacked
the killer piece of evidence
that would settle things decisively.

592
00:51:09,007 --> 00:51:14,058
The conflict seemed destined
to remain unresolved.

593
00:51:14,093 --> 00:51:18,579
Then south of New York, close
to the mean streets of New Jersey,

594
00:51:18,614 --> 00:51:24,856
an unlikely piece of equipment
was to make one of the most important
discoveries of the century

595
00:51:24,891 --> 00:51:27,538
and settle the argument
once and for all.

596
00:51:56,587 --> 00:51:59,968
This giant piece
of sadly rusting machinery

597
00:52:00,003 --> 00:52:03,350
is the Bell Labs horn antenna
in New Jersey.

598
00:52:03,385 --> 00:52:05,716
It's in fact a radio telescope

599
00:52:05,751 --> 00:52:09,953
but rather than looking like
the more traditional satellite dish

600
00:52:09,987 --> 00:52:14,153
it has this huge horn-like structure
that could be rotated round

601
00:52:14,188 --> 00:52:17,599
to face the sky
and pick up radio signals from space.

602
00:52:17,634 --> 00:52:24,358
It's a bit like a giant hearing aid
but it could pinpoint very, very
weak signals extremely accurately.

603
00:52:24,393 --> 00:52:27,198
It was originally built for research
into satellite communication

604
00:52:27,233 --> 00:52:29,843
but instead it was used
in the mid-1960s

605
00:52:29,878 --> 00:52:35,361
to make
one of the most important discoveries
in the history of science.

606
00:52:38,722 --> 00:52:42,808
Two researchers,
Arno Penzias and Robert Wilson

607
00:52:42,843 --> 00:52:47,364
had got hold of this antenna
in 1963 from Bell Laboratories

608
00:52:47,400 --> 00:52:50,250
with the intention of doing research

609
00:52:50,285 --> 00:52:54,447
into the faint halo of hydrogen
around the Milky Way.

610
00:52:56,048 --> 00:52:59,373
Before Penzias and Wilson
could begin their experiment,

611
00:52:59,408 --> 00:53:04,209
they had to make sure they got rid
of all the background noise
the antenna was picking up.

612
00:53:04,244 --> 00:53:07,457
It's a bit like the hiss
on radios in between stations.

613
00:53:07,492 --> 00:53:12,413
They spent the best part of a year
checking all the equipment
and the electronics,

614
00:53:12,448 --> 00:53:16,672
they even got down on
their hands and knees inside the dish

615
00:53:16,707 --> 00:53:20,896
to scrub it clean of what they called
white dielectric material

616
00:53:20,931 --> 00:53:23,061
which was basically pigeon crap.

617
00:53:23,096 --> 00:53:27,818
But even after all this there was
still a faint persistent hiss
they couldn't get rid of

618
00:53:27,853 --> 00:53:30,979
and it was there whichever direction
the antenna pointed.

619
00:53:34,421 --> 00:53:37,907
There was
only one viable explanation.

620
00:53:37,942 --> 00:53:45,423
The noise was the sound of radiation,
the afterglow of Gamow's Big Bang.

621
00:53:45,458 --> 00:53:48,225
THUNDEROUS BANG

622
00:53:52,307 --> 00:53:56,788
Here at last was final proof
that Gamow was right,

623
00:53:56,823 --> 00:53:59,948
the Big Bang had to have happened.

624
00:54:05,031 --> 00:54:08,557
You see,
soon after the universe was created

625
00:54:08,592 --> 00:54:13,875
about 300,000 years
after the Big Bang
it had expanded and cooled enough

626
00:54:13,910 --> 00:54:17,352
for the atoms of
the lightest elements to form,

627
00:54:17,387 --> 00:54:20,760
leaving the whole universe
awash with light.

628
00:54:20,795 --> 00:54:25,637
Now George Gamow
had earlier predicted
that this afterglow of creation

629
00:54:25,672 --> 00:54:29,965
would today be in
the form of weak microwave radiation.

630
00:54:30,000 --> 00:54:36,401
You can actually hear this radiation
as a tiny fraction of the hiss on
your radio or TV in between channels.

631
00:54:41,523 --> 00:54:46,044
The detection
of this cosmic background radiation
by Penzias and Wilson

632
00:54:46,079 --> 00:54:50,566
showed that Gamow's Big Bang theory
was correct and that he was right

633
00:54:50,601 --> 00:54:54,813
about how hydrogen and helium
were formed in the early universe.

634
00:54:54,848 --> 00:55:00,810
So this, together with Hoyle
and Fowler's theories about how
the atoms of all the heavier elements

635
00:55:00,845 --> 00:55:04,215
were cooked inside stars
gave us the complete picture.

636
00:55:04,250 --> 00:55:10,373
We finally understood how the atoms
of all the elements in the universe
were made.

637
00:55:16,096 --> 00:55:21,061
In less than 100 years,
science has performed a miracle.

638
00:55:21,096 --> 00:55:26,259
It had truly explained where
we come from and was able to describe

639
00:55:26,294 --> 00:55:30,180
the entire 14 billion year history
of the cosmos.

640
00:55:30,215 --> 00:55:32,700
In the beginning was the Big Bang...

641
00:55:32,735 --> 00:55:34,707
BANG!

642
00:55:34,742 --> 00:55:37,786
..an explosion of unimaginable power.

643
00:55:37,822 --> 00:55:41,148
In the following ten minutes
in the searing heat,

644
00:55:41,183 --> 00:55:46,665
the nuclei of just two types of atom
emerged, hydrogen and helium.

645
00:55:46,700 --> 00:55:52,507
For the next 300,000 years
the universe expanded.

646
00:55:52,542 --> 00:55:55,884
At that point
another cosmic chapter began.

647
00:55:55,919 --> 00:55:59,229
Individual atoms separated out
from each other,

648
00:55:59,264 --> 00:56:02,996
as they did this,
they released light.

649
00:56:03,031 --> 00:56:09,873
It's the remnants of this light
that Penzias and Wilson
picked up with their horn antenna.

650
00:56:09,908 --> 00:56:17,113
Then, millions of years after this,
massive clouds of hydrogen
coalesced into the first stars.

651
00:56:17,148 --> 00:56:24,319
In here they began to fuse,
producing starlight and eventually
all the other types of atoms

652
00:56:24,354 --> 00:56:26,359
that exist in the universe today.

653
00:56:35,202 --> 00:56:42,844
Our Earth and everything on it,
including our own bodies, was forged
long ago in the crucibles of space.

654
00:56:42,879 --> 00:56:47,243
For instance, my body
is almost three-quarters water

655
00:56:47,278 --> 00:56:51,572
which we know is made up
of oxygen and hydrogen atoms.

656
00:56:51,607 --> 00:56:55,850
We now understand that hydrogen
was formed 13 billion years ago,

657
00:56:55,885 --> 00:56:59,811
soon after the Big Bang itself
whereas oxygen had to wait

658
00:56:59,846 --> 00:57:02,575
to be cooked
inside stars like our sun.

659
00:57:02,610 --> 00:57:06,412
The same is true of another
important element in my body, carbon,

660
00:57:06,447 --> 00:57:10,099
the element on which
all life forms on Earth are based.

661
00:57:10,134 --> 00:57:17,015
But my body also contains
other elements in smaller amounts,
like iron.

662
00:57:17,050 --> 00:57:18,341
This element was formed
during the dying embers

663
00:57:18,376 --> 00:57:24,539
of gigantic stars as they ground
towards the ends of their lives.

664
00:57:24,574 --> 00:57:27,544
There are also
trace elements like zinc.

665
00:57:27,579 --> 00:57:30,786
There are only two grams of zinc
in my body but this element

666
00:57:30,821 --> 00:57:37,023
had to be created during a supernova,
the explosion of a giant star
with cosmic violence

667
00:57:37,058 --> 00:57:42,349
during which lighter atoms
are fused together to form
heavier elements.

668
00:57:42,384 --> 00:57:48,387
The same is true for all naturally
occurring elements, they are
all cooked in cosmic cauldrons.

669
00:57:48,422 --> 00:57:52,265
Romantically, you could say
that we're all made of stardust

670
00:57:52,300 --> 00:57:56,109
but the truth is also
that we're all just nuclear waste.