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BEEPING, JUMBLED VOICES

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BEEPING, RADIO INTERFERENCE

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JUMBLED VOICES

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Our planet is filled with signals
invisible to the naked eye.

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'Two, one, zero...'

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But space itself can be
just as noisy.

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JUMBLED VOICES

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This is Cambridge University's
Radio Telescope Observatory.

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It's used to examine
the far reaches of space.

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To answer questions about
the very origin of our universe.

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These magnificent dishes

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are detecting signals from radiation

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left over from the Big Bang.

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But they're not optical telescopes,
in the sense of looking

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through an eyepiece
and seeing a planet or a star.

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These dishes
are detecting radio waves.

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These telescopes allow us
to see the unseen.

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Extraordinary images
like these are made possible

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thanks to radio waves...

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..microwaves...

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..and gamma rays.

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The thing is, all these waves
are connected.

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They're all different types
of something we call

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electromagnetic radiation.

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Visible light - the light
that you and I can see -

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is just a tiny portion
of this broader spectrum of waves.

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We use waves to probe
the outer reaches of our universe.

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But we use them for so much more.

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In fact, electromagnetic waves are
at the heart of modern technology.

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We use them every day, in everything
from medicine to communications.

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'There it is. There it is.'

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Our mastery of these waves
was made possible

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when one man published
a set of equations in 1865.

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A man called James Clerk Maxwell.

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His name is barely known
to the public.

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And yet, he's probably the finest
scientist Scotland has ever produced.

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And 150 years after
his greatest discovery,

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I'm setting out to explore
the story of the man and his work.

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Excuse me, can I ask you a question?
Do you recognise this person?

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No?

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Do you know who he is?

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Alexander Graham Bell?

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No idea.

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He looks like a banker...
An economist, maybe?

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James Clerk Maxwell.

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Still no idea? Still no idea.

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James Clerk Maxwell.
Never heard of him.

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Albert Einstein or something.
You're so close!

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James Clerk Maxwell.

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Name ring a bell? Maxwell's
equations. Maxwell's equations.

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I don't know what they're about,
but I've heard of them.

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Right, you do physics? I do physics.

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OK. James Clerk Maxwell, then.
This is your test.

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I just failed at physics!

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That's his statue. Is it?
That's his statue.

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That's his statue. Oh!

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You probably pass that quite
regularly. Quite regularly,

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so it is quite an embarrassment
to say... No, but no-one.

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I've been asking everyone here.

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James Clerk Maxwell.

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No-one knows who he is?

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Any ideas?

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This is a statue
of James Clerk Maxwell,

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and yet virtually no-one around here
knows who he is!

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But I don't blame them because
Maxwell seems to have slipped through

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the cracks of history, at least
as far as the public is concerned.

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So who was he?

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James Clerk Maxwell was
a 19th-century Scottish scientist

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who used his genius to work
across a wide range of subjects.

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Astronomy, physiology, colour,

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optics, thermodynamics,

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electricity and magnetism.

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He touched on all of these...

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..and changed many of them
beyond recognition.

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He caused a revolution in physics

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and gave us the laws for one
of the four fundamental forces

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of the universe.

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Einstein kept a picture of Maxwell
on the wall of his study

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and once said,
"I stand on the shoulders

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"of James Clerk Maxwell."

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It's a sentiment shared
by many physicists today.

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Maxwell did for electricity
and magnetism

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what Isaac Newton did for gravity.

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He's one of my great heroes.

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He's one of the greatest scientists
we're ever, ever going to encounter.

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He's on a par with Einstein,

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with Newton, with Archimedes.

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He transformed our way
in which we understand the world.

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He's probably the greatest scientist
Scotland has ever produced,

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and we're still living in the shadow
of his achievements.

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And yet, no-one knows who he is!

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Even me - a Scot and a scientist -

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I've just got this vague notion
of what he did.

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But I want to change that.

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I want to rediscover
James Clerk Maxwell.

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Born in Edinburgh in 1831,

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Maxwell was the only child in a
land-owning family from Galloway.

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The scientific revolution
of the previous centuries was

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changing our view of the world.

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But modern science
was still in its infancy.

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The 19th century would see
ground-breaking discoveries.

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And Maxwell would be at the heart
of it, compelled by a probing mind.

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His inquisitive nature was obvious,
even in childhood.

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When he was a boy, the zoetrope
was a new invention.

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And the young Maxwell loved them.

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It's kind of hypnotic.
HE CHUCKLES

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In a sense, these are the forerunners
of movies and television,

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and you can imagine kids
in the 19th century just

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being mesmerised by them.

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Most of them would have been
happy to just sit back

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and enjoy the show, but Maxwell
wanted to know how they worked.

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The moving figures
are a trick of the eye.

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Stop the drum spinning,

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and you can see the simple sketches
that help create the moving image.

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This simple illusion
captivated Maxwell.

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As a child, he would build
his own zoetrope strips

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to entertain his family
and to understand how they worked.

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This desire to understand the world
around him

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continued into adulthood.

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Aged just 14, he produced a paper
on geometric shapes that showed

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such mathematical ingenuity
it was published...

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..and then read at
the Royal Society of Edinburgh

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by an established professor,
as James was deemed too young.

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As a teenager, he conducted
home-made experiments

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into light and colour.

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And by the time he arrived
at Cambridge University,

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aged 19, he had already published
three mathematical papers.

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From the age of 14,

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Maxwell had been using mathematics
to explain how the world worked.

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It was a talent he would rely on
for many of his discoveries,

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and it was key to establishing
his scientific reputation.

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Because, while still in his 20s,
he used maths to solve

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a riddle that had puzzled
scientists for centuries.

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Saturn's rings.

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A vivid band surrounding one
of our solar system's giant planets.

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We've become accustomed
to their beauty.

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But in previous centuries,
they were an enigma.

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Galileo first drew them in 1610,

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and they immediately
fascinated astronomers.

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Sometimes the rings were hidden.

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At other times,
clearly visible in the night sky.

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By the mid-19th century,
we knew the rings were composed

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of at least two vast
concentric circles -

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over 250,000 kilometres in diameter.

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But what were the rings made of?

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And why did they stay in place?

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In 1855, a Cambridge college
published an open competition

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to answer those very questions.

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But the answer would have to be
accompanied by

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a full mathematical proof.

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Maxwell's response would earn him

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his stripes as one
of Britain's top physicists.

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There were three possible
explanations for Saturn's rings.

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One possibility was that the rings
were solid rock or ice.

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Another, that they
were entirely fluid.

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A third explanation
said the rings were made up

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of lots of individual particles
that circled Saturn.

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As the rings were over
a billion kilometres away,

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proving which explanation
was right seemed impossible.

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So how did Maxwell go about kind of
disentangling those options?

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Well, with great difficulty!
I bet you!

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Of course, what's really striking,
what's very impressive,

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is that he did it using pure maths.

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And you wouldn't perhaps instantly
think that this was a problem

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you could tackle that way. You'd
think, well, the way to do it

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is to just build a big telescope
and have a look.

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But the mathematics that Maxwell
brought to bear on this

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allowed him to look
at these three cases

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and to basically decide which one
of them was the correct answer.

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So if we take first of all the case
of a completely solid ring,

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there's a particular mathematical
equation that describes

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that case -

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the distance from the centre of the
planet to the centre of the rings,

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that's this big R here.

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MUTED SPEECH

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The maths IS incredibly complicated.

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And as a geologist,
I'm a bit out of my depth!

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But I understand the basic point.

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Maxwell reduced the physical world
to mathematical symbols,

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and then used maths to predict
what was happening around Saturn.

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Maxwell said that a solid ring
was possible,

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but only if most of the material
was bunched together

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on one side of the planet.

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And, of course, if you look through
a telescope, it doesn't look like

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that, so that model was discarded.

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Back to the drawing board.

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Maxwell then assumed
that the rings were fluid.

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He came up with an equation
to describe how that might work.

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Off he goes with
these complicated mathematics.

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He found that
if the rings were fluid,

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physical forces acting on them would
eventually break them up into lumps.

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So he discounted this possibility.

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And that leaves
the third possibility,

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which is that the rings consist
of a very large number

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of independently moving particles,

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particles that are all
orbiting Saturn,

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on their own.

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And what he boiled all of that down
to was an equation to tell you

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how many particles you would need in
order to have the system stable.

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And sure enough, this seemed to
work. So it wasn't just

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that he'd shown that the other two
possibilities were wrong,

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but that this third possibility
did actually work as well.

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What I find staggering is just
the notion that you can just use

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numbers to predict something.
You've got absolutely,

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you know, no knowledge
about it directly. Sure.

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I think,

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for me, that's almost
a watershed moment

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in how we do physics because,
you know, it laid the foundations

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for really how we do physics today.
Because there's many examples,

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everything from, say,
the Higgs Boson

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to studying distant galaxies,

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where you can make
theoretical predictions

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and it might be years or decades

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or even centuries before you can
fully test those predictions.

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But, hey, it works.

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We're just zooming in
on the ring plane.

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That's great, isn't it?!
Yeah, amazing.

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Here we are! We're in the ring!

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Look at that.

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What do you think Maxwell
would have given to have seen this?

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00:13:11,780 --> 00:13:14,260
HE LAUGHS
Oh, I'm sure he would have loved it.

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Almost 130 years after
Maxwell's prediction,

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we captured images that proved
his theory beyond doubt.

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In 1977, an ambitious NASA
launched the Voyager probe.

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Three years later, it sent home
sensational images of Saturn's rings.

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In 2009, the Cassini probe
confirmed those findings.

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Saturn's rings were made
of millions of icy rocks.

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In recognition of his work,

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a division between the rings
is known as the Maxwell Gap.

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But his maths has been
applied beyond Saturn.

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This image from
the Taurus Constellation

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shows a young sun at the heart
of a huge cloud of dust and rocks.

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As the cloud circles the star,

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dark bands reveal areas where rocks

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are clumping together
to form planets.

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We're witnessing
the birth of a solar system.

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And the maths we use
to understand this process

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is the same as Maxwell's work
on Saturn's rings.

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Maths is a powerful tool that
physicists use to understand,

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to predict the universe.

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And Maxwell was a master of it.

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In solving the problem
of Saturn's rings,

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Maxwell had put a marker down -

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00:14:47,820 --> 00:14:51,460
he wanted the scientific
establishment to take him seriously.

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00:14:51,460 --> 00:14:52,540
And they did.

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00:14:56,380 --> 00:14:58,340
When Maxwell delivered his paper,

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it was the only one that
the Cambridge committee received.

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00:15:01,420 --> 00:15:03,700
No-one else come up
with an explanation.

249
00:15:05,060 --> 00:15:08,140
Overnight, Maxwell became known
as one of Britain's great

250
00:15:08,140 --> 00:15:09,540
theoretical physicists.

251
00:15:10,980 --> 00:15:13,620
This wasn't a surprise
to those who knew him

252
00:15:13,620 --> 00:15:15,860
because his teenage precociousness

253
00:15:15,860 --> 00:15:20,660
had been followed by ground-breaking
experiments as an undergraduate.

254
00:15:20,660 --> 00:15:23,900
So perhaps it's no wonder
that Maxwell was made professor

255
00:15:23,900 --> 00:15:28,060
here at Aberdeen's Marischal College
at the tender age of 25.

256
00:15:28,060 --> 00:15:30,020
His star was on the rise.

257
00:15:33,020 --> 00:15:35,220
His career may have been taking off,

258
00:15:35,220 --> 00:15:38,380
but this was a difficult time
for Maxwell.

259
00:15:38,380 --> 00:15:42,340
An only child, he'd been extremely
close to his parents.

260
00:15:42,340 --> 00:15:44,500
But his mother had died
when he was eight.

261
00:15:44,500 --> 00:15:47,740
And just a few months before
Maxwell arrived in Aberdeen,

262
00:15:47,740 --> 00:15:48,900
he lost his father.

263
00:15:50,780 --> 00:15:54,340
Maxwell expressed his grief
in a letter to a friend.

264
00:15:54,340 --> 00:15:57,700
But the passage gives a revealing
insight into his humanity

265
00:15:57,700 --> 00:16:00,740
and the deep feelings
he had for family and friends.

266
00:16:02,020 --> 00:16:03,540
"Either be a machine

267
00:16:03,540 --> 00:16:05,860
"and see nothing but phenomena,

268
00:16:05,860 --> 00:16:08,460
"or else try to be a man,

269
00:16:08,460 --> 00:16:10,300
"feeling your life interwoven,
as it is,

270
00:16:10,300 --> 00:16:11,900
"with many others,

271
00:16:11,900 --> 00:16:15,580
"and strengthened by them,
whether in life or death."

272
00:16:18,020 --> 00:16:21,260
Maxwell's move to Aberdeen
meant he was far from friends

273
00:16:21,260 --> 00:16:23,460
and amongst colleagues
twice his age.

274
00:16:25,460 --> 00:16:27,140
He threw himself into his work.

275
00:16:28,780 --> 00:16:31,580
Whether it was his industry
or his solitude,

276
00:16:31,580 --> 00:16:34,580
Maxwell came to the attention
of the college principal,

277
00:16:34,580 --> 00:16:36,140
Reverend Daniel Dewar.

278
00:16:37,500 --> 00:16:40,100
Dewar befriended his new professor,

279
00:16:40,100 --> 00:16:43,180
for dinner,

280
00:16:43,180 --> 00:16:46,340
which is how he met
the principal's daughter, Katherine.

281
00:16:48,100 --> 00:16:50,300
Maxwell's relationship
with Katherine reveals

282
00:16:50,300 --> 00:16:54,460
the character of the man
beyond his scientific genius.

283
00:16:54,460 --> 00:16:57,180
Deeply affectionate,
he had a lively sense of humour

284
00:16:57,180 --> 00:16:58,620
and a passion for poetry.

285
00:16:59,900 --> 00:17:01,740
As their relationship blossomed,

286
00:17:01,740 --> 00:17:04,780
Maxwell plucked up the courage
to ask Katherine to share

287
00:17:04,780 --> 00:17:08,500
their lives together - and his
marriage proposal included a poem.

288
00:17:09,740 --> 00:17:11,340
Will you come along with me

289
00:17:11,340 --> 00:17:13,460
In the fresh spring tide

290
00:17:13,460 --> 00:17:15,020
My comforter to be

291
00:17:15,020 --> 00:17:16,500
Through the world so wide?

292
00:17:16,500 --> 00:17:18,420
And the life that we shall lead

293
00:17:18,420 --> 00:17:20,540
In the fresh spring tide

294
00:17:20,540 --> 00:17:22,660
Will make you mine indeed

295
00:17:22,660 --> 00:17:25,020
Though the world so wide

296
00:17:25,020 --> 00:17:27,340
No stranger's blame or praise

297
00:17:27,340 --> 00:17:29,020
Will turn us from our ways

298
00:17:29,020 --> 00:17:30,820
That brought us happy days

299
00:17:30,820 --> 00:17:32,740
On our ain burnside.

300
00:17:35,780 --> 00:17:39,060
Maxwell married Katherine in 1858.

301
00:17:39,060 --> 00:17:42,700
And throughout their lives,
they remained devoted to each other.

302
00:17:44,740 --> 00:17:48,780
She would be a valued assistant
in many of his future experiments

303
00:17:48,780 --> 00:17:50,820
and even became a willing guinea pig

304
00:17:50,820 --> 00:17:52,980
for one of his great obsessions.

305
00:18:00,780 --> 00:18:03,660
Strange as it may seem,
in Maxwell's time,

306
00:18:03,660 --> 00:18:08,020
we didn't really know what colour
was, or why we saw colour at all.

307
00:18:10,300 --> 00:18:14,020
In the 17th century, Isaac Newton
had given us food for thought.

308
00:18:15,180 --> 00:18:18,460
By using a prism,
he had split sunlight into separate

309
00:18:18,460 --> 00:18:21,020
colours - the familiar
colours of the rainbow.

310
00:18:23,340 --> 00:18:26,260
He showed that what we perceive
as white light

311
00:18:26,260 --> 00:18:28,740
is actually a mixture
of different colours.

312
00:18:31,740 --> 00:18:35,300
Newton said that every colour
we see was the result of mixing

313
00:18:35,300 --> 00:18:38,260
the colours we see in the rainbow.

314
00:18:38,260 --> 00:18:42,220
He tried - and failed - to establish
the rules of mixing.

315
00:18:43,460 --> 00:18:47,260
150 years later,
we weren't much wiser.

316
00:18:47,260 --> 00:18:49,180
Maxwell was interested in colour -

317
00:18:49,180 --> 00:18:50,780
and why we perceive it -

318
00:18:50,780 --> 00:18:52,020
throughout his life.

319
00:18:56,100 --> 00:18:59,500
And his first real breakthrough
came as a Cambridge student.

320
00:19:01,900 --> 00:19:05,180
Artists seemed to be ahead
of scientists on this.

321
00:19:07,460 --> 00:19:09,660
For centuries,
they had been creating a vast

322
00:19:09,660 --> 00:19:14,300
palette of colours, often by just
mixing red, blue and yellow.

323
00:19:17,900 --> 00:19:21,100
Artists referred to these three
as the primary colours -

324
00:19:21,100 --> 00:19:25,300
and using them, they could create
entirely different colours.

325
00:19:25,300 --> 00:19:28,900
So if a painter was mixing
red and yellow,

326
00:19:28,900 --> 00:19:29,980
they would get orange.

327
00:19:32,020 --> 00:19:35,020
And if he was mixing blue and red,
then he'd get purple.

328
00:19:37,740 --> 00:19:41,540
But if he was mixing blue and yellow,
then he would get green.

329
00:19:44,140 --> 00:19:48,700
As a student, Maxwell read
about the work of Thomas Young.

330
00:19:48,700 --> 00:19:50,580
Young thought that there
was something

331
00:19:50,580 --> 00:19:53,340
significant about the number
of primary colours.

332
00:19:54,940 --> 00:19:57,460
But he also thought biology
had a role to play.

333
00:19:59,260 --> 00:20:01,900
Young argued that the human eye
had three receptors in it,

334
00:20:01,900 --> 00:20:05,540
each one sensitive
to a particular colour.

335
00:20:05,540 --> 00:20:08,620
He argued that the brain worked
like a painter, combining messages

336
00:20:08,620 --> 00:20:12,660
from each receptor to build up
this perception of colour.

337
00:20:14,500 --> 00:20:17,500
It was a stroke of intuitive genius.

338
00:20:17,500 --> 00:20:19,020
He just didn't have any proof.

339
00:20:24,100 --> 00:20:27,740
Young thought that these receptors
corresponded to the painter's

340
00:20:27,740 --> 00:20:29,540
primary colours.

341
00:20:29,540 --> 00:20:32,940
Taken by Young's
three-colour theory,

342
00:20:32,940 --> 00:20:34,460
Maxwell wanted to test it.

343
00:20:36,820 --> 00:20:39,220
He devised a way to mix
the primary colours

344
00:20:39,220 --> 00:20:40,980
with mathematical precision.

345
00:20:42,180 --> 00:20:45,980
He then tested those mixtures
on a wide range of people

346
00:20:45,980 --> 00:20:48,380
to see if they all perceived
the same colour.

347
00:20:49,420 --> 00:20:52,340
And he did this with
a deceptively simple tool.

348
00:20:54,460 --> 00:20:57,300
So this looks old.
What is this, then?

349
00:20:57,300 --> 00:20:59,380
This is Maxwell's
original colour wheel,

350
00:20:59,380 --> 00:21:01,980
which we are very pleased
to have in the laboratory.

351
00:21:01,980 --> 00:21:03,380
So that's the original thing.

352
00:21:03,380 --> 00:21:05,260
It's the original thing.

353
00:21:05,260 --> 00:21:07,860
It's slightly beaten up -
it's been used a lot.

354
00:21:07,860 --> 00:21:11,940
And that's because Maxwell used this
to test out the mixing

355
00:21:11,940 --> 00:21:15,980
of lights among all his friends
when he was here in Trinity College.

356
00:21:15,980 --> 00:21:19,100
It is...pretty antique,
as you can see,

357
00:21:19,100 --> 00:21:23,780
but the idea is, you put different
amounts of the coloured papers here,

358
00:21:23,780 --> 00:21:26,980
and then when you rotate them,
then they mix up.

359
00:21:26,980 --> 00:21:31,820
And this works because of
the...because of... The typical time

360
00:21:31,820 --> 00:21:34,420
the eye can respond
is a 20th of a second.

361
00:21:34,420 --> 00:21:37,380
And so if it goes faster,
the eye will interpret this

362
00:21:37,380 --> 00:21:38,780
as a mixture of the colours.

363
00:21:38,780 --> 00:21:40,380
And this is a motorised
version of it.

364
00:21:40,380 --> 00:21:41,900
This is a motorised version of it.

365
00:21:41,900 --> 00:21:45,660
And we can actually demonstrate
how the colour mixing works with

366
00:21:45,660 --> 00:21:48,380
this rather pretty
demonstration here.

367
00:21:48,380 --> 00:21:51,100
We're going to mix red and blue.

368
00:21:51,100 --> 00:21:55,180
We'll rotate it rapidly and then
we'll see which colour we produce.

369
00:21:56,660 --> 00:21:59,020
Just like his childhood zoetrope,

370
00:21:59,020 --> 00:22:03,900
Maxwell's colour wheel would spin
so fast it would trick the human eye.

371
00:22:03,900 --> 00:22:06,380
So if you were going to bring up
that light... This one here?

372
00:22:06,380 --> 00:22:07,820
That's right.

373
00:22:07,820 --> 00:22:11,780
'Instead of moving figures, he'd be
mixing colours just as artists did,

374
00:22:11,780 --> 00:22:14,380
'but with mathematical precision.'

375
00:22:16,820 --> 00:22:20,380
When he mixed red and blue,
he got the same colour artists did

376
00:22:20,380 --> 00:22:22,020
when they mixed paint.

377
00:22:22,020 --> 00:22:24,740
That's kind of magenta,
proper magenta.

378
00:22:24,740 --> 00:22:27,140
Yes, it's a sort of magenta colour.

379
00:22:27,140 --> 00:22:29,980
If Young was right and there were
receptors in our eye that

380
00:22:29,980 --> 00:22:33,580
responded to the artist's primary
colours, then perhaps mixing

381
00:22:33,580 --> 00:22:37,140
red, yellow and blue in equal
measure would produce white.

382
00:22:39,060 --> 00:22:40,620
But it didn't.

383
00:22:40,620 --> 00:22:43,580
So Maxwell tried
different combinations.

384
00:22:43,580 --> 00:22:48,580
We can begin now to reveal green,
as well as blue here.

385
00:22:48,580 --> 00:22:52,540
And if we just do a little bit
of fiddling around with these discs,

386
00:22:52,540 --> 00:22:56,780
we'll be able to get equal amounts
of red, green and blue,

387
00:22:56,780 --> 00:23:00,340
and we can then see what colours
we observe, OK?

388
00:23:18,180 --> 00:23:19,860
So it's white. I mean, it's white.

389
00:23:19,860 --> 00:23:22,340
It's the only colour
you could call that. White.

390
00:23:25,060 --> 00:23:28,140
So this was a beautiful
demonstration of the fact

391
00:23:28,140 --> 00:23:32,700
that the primary lights - and notice
the word light, not pigment -

392
00:23:32,700 --> 00:23:36,500
the primary lights
are red, blue and green.

393
00:23:36,500 --> 00:23:40,940
And you can create any colour
of light by suitable mixture

394
00:23:40,940 --> 00:23:43,060
of different proportions of these.

395
00:23:43,060 --> 00:23:46,300
What happens in paintings -
pigments absorb light,

396
00:23:46,300 --> 00:23:47,980
whereas this is emitting light.

397
00:23:47,980 --> 00:23:51,860
So the upshot of all of this was
that Maxwell was able to produce

398
00:23:51,860 --> 00:23:54,820
a rather beautiful
colour triangle diagram

399
00:23:54,820 --> 00:23:57,900
which would indicate
how you would create ANY colour

400
00:23:57,900 --> 00:24:00,180
by mixing the three primary colours.

401
00:24:03,300 --> 00:24:07,140
Maxwell's colour triangle allowed
him to pick a specific colour

402
00:24:07,140 --> 00:24:10,460
and work out how much of each
primary colour would be needed

403
00:24:10,460 --> 00:24:12,060
to reproduce it.

404
00:24:12,060 --> 00:24:14,940
This was made possible
by his mathematical precision

405
00:24:14,940 --> 00:24:17,220
and systematic testing.

406
00:24:17,220 --> 00:24:20,540
Maxwell's work swept aside
a sea of confusion.

407
00:24:20,540 --> 00:24:24,700
He vindicated Young's theory
and demonstrated that we see

408
00:24:24,700 --> 00:24:28,540
colours in paints differently to
the way we see colours in light.

409
00:24:29,980 --> 00:24:34,940
He established the primary colours
for light as red, blue and green.

410
00:24:36,500 --> 00:24:39,620
He realised the receptors in our
eyes were sensitive to those three.

411
00:24:42,380 --> 00:24:45,900
And that by mixing them,
we perceived a vast range of colours.

412
00:24:49,140 --> 00:24:51,100
A few years later,

413
00:24:51,100 --> 00:24:54,940
he provided a stunning display
that he was right.

414
00:24:59,540 --> 00:25:03,860
In 1861, Maxwell was invited to
the Royal Institution in London

415
00:25:03,860 --> 00:25:05,860
to give a lecture on colour vision.

416
00:25:09,260 --> 00:25:12,220
But he didn't want to just
talk about the principles,

417
00:25:12,220 --> 00:25:14,860
he wanted to demonstrate them
to his audience.

418
00:25:20,540 --> 00:25:23,820
What he did would astonish them.

419
00:25:23,820 --> 00:25:27,660
Maxwell took three photographs
of the same object.

420
00:25:27,660 --> 00:25:30,340
Each photo had a different
filter on it -

421
00:25:30,340 --> 00:25:33,820
one was red, one was green
and one was blue.

422
00:25:33,820 --> 00:25:37,340
That gave Maxwell three photographic
plates that he could use

423
00:25:37,340 --> 00:25:39,020
to project an image with.

424
00:25:40,260 --> 00:25:42,980
When Maxwell projected the image
from the red photograph

425
00:25:42,980 --> 00:25:45,500
onto the wall,
he got a red picture.

426
00:25:47,580 --> 00:25:49,860
In an age when photography
was black and white,

427
00:25:49,860 --> 00:25:53,100
this was INTERESTING
but hardly revolutionary.

428
00:25:53,100 --> 00:25:58,540
But if you project all three images
onto the wall at the exact same spot,

429
00:25:58,540 --> 00:26:00,380
something special happens.

430
00:26:06,980 --> 00:26:08,500
The audience were looking

431
00:26:08,500 --> 00:26:10,700
at the world's first
colour photograph.

432
00:26:12,700 --> 00:26:13,780
They were stunned.

433
00:26:17,820 --> 00:26:20,980
Maxwell had chosen the perfect
subject for his picture -

434
00:26:20,980 --> 00:26:23,300
a brightly coloured tartan ribbon.

435
00:26:24,420 --> 00:26:27,900
By layering red, green and blue
images on top of each other,

436
00:26:27,900 --> 00:26:32,060
Maxwell established the possibility
of creating colour photographs.

437
00:26:35,540 --> 00:26:39,500
150 years later,
we use this method daily,

438
00:26:39,500 --> 00:26:43,140
because this three-colour principle
is used in colour TV,

439
00:26:43,140 --> 00:26:46,060
computer screens,
even mobile phones.

440
00:26:47,780 --> 00:26:51,500
The colours we see on our screens,
however big or small,

441
00:26:51,500 --> 00:26:54,580
are created by carefully mixing
the primary colours.

442
00:26:57,420 --> 00:27:01,540
Maxwell's work on colour provides
the basis for our present

443
00:27:01,540 --> 00:27:03,300
understanding of colour vision.

444
00:27:04,540 --> 00:27:06,260
He even proposed an explanation

445
00:27:06,260 --> 00:27:08,420
for why some people
were colour-blind.

446
00:27:08,420 --> 00:27:11,660
He said the receptors
in their eyes were faulty,

447
00:27:11,660 --> 00:27:14,740
and that this radically altered
how they perceived colour.

448
00:27:17,140 --> 00:27:20,100
Three weeks after his colour show,
Maxwell was elected to the

449
00:27:20,100 --> 00:27:24,140
Royal Society for his work
on Saturn's rings and on colour.

450
00:27:24,140 --> 00:27:26,860
He was now counted amongst
the finest physicists in Britain.

451
00:27:27,940 --> 00:27:29,220
And he was 29.

452
00:27:33,100 --> 00:27:34,420
Despite his success,

453
00:27:34,420 --> 00:27:37,740
a year earlier Maxwell
had found himself out of a job.

454
00:27:39,740 --> 00:27:43,020
When Marischal College merged
with Aberdeen University,

455
00:27:43,020 --> 00:27:45,940
he had lost out
to an older professor.

456
00:27:45,940 --> 00:27:49,860
Out of work, Maxwell and Katherine
took a trip to the country,

457
00:27:49,860 --> 00:27:51,900
to somewhere very special to James.

458
00:27:54,900 --> 00:27:59,780
A quiet place hidden deep
in Galloway, just west of Dumfries.

459
00:27:59,780 --> 00:28:01,820
A place called Glenlair.

460
00:28:01,820 --> 00:28:03,460
His family home.

461
00:28:05,540 --> 00:28:07,860
Maxwell's family had been
established in the area

462
00:28:07,860 --> 00:28:10,820
for centuries,
and Glenlair was a working estate.

463
00:28:13,740 --> 00:28:17,900
He was born in Edinburgh, but James
had spent an idyllic childhood here.

464
00:28:17,900 --> 00:28:20,900
FAINT CHILDREN'S LAUGHTER

465
00:28:20,900 --> 00:28:23,940
Playing in the fields,
swimming in the stream,

466
00:28:23,940 --> 00:28:28,220
running through the woods,
nature truly was his playground.

467
00:28:28,220 --> 00:28:32,340
And that fostered a curiosity
about how the natural world worked.

468
00:28:34,980 --> 00:28:36,580
For the first decade of his life,

469
00:28:36,580 --> 00:28:39,220
Maxwell was home-schooled
by his mother.

470
00:28:39,220 --> 00:28:42,660
She encouraged his inquisitiveness.

471
00:28:42,660 --> 00:28:46,580
"Look up through nature," she said,
"up to nature's god."

472
00:28:50,460 --> 00:28:54,940
Glenlair remained an important place
to Maxwell throughout his life.

473
00:28:54,940 --> 00:28:57,300
It was somewhere that rooted him.

474
00:28:57,300 --> 00:28:59,460
A safe haven. A home.

475
00:29:01,500 --> 00:29:05,020
And the current owner of Glenlair
knows just how that feels.

476
00:29:06,660 --> 00:29:09,020
So what was it like
growing up at Glenlair?

477
00:29:09,020 --> 00:29:13,900
Well, I was a ten-year-old
little boy when I came here,

478
00:29:13,900 --> 00:29:17,180
and I had the run of the place.

479
00:29:17,180 --> 00:29:19,740
My dad was quite an old chap and...

480
00:29:19,740 --> 00:29:24,820
he and my mother - and I was
an only child, they were elderly -

481
00:29:24,820 --> 00:29:27,140
so they didn't really
keep an eye on me.

482
00:29:27,140 --> 00:29:30,580
My childhood must have almost
mirrored his,

483
00:29:30,580 --> 00:29:32,260
although I was slightly older.

484
00:29:32,260 --> 00:29:34,700
But I mean, a lot of
his stuff's theoretical.

485
00:29:34,700 --> 00:29:37,580
It's kind of just thinking,
difficult thinking.

486
00:29:37,580 --> 00:29:40,340
This seems a good place
for theoretical thinkers.

487
00:29:40,340 --> 00:29:44,540
Yes, yes. And we have loads
of professors who visit here.

488
00:29:44,540 --> 00:29:47,500
And nearly all of them stand here,

489
00:29:47,500 --> 00:29:50,980
and they look out at that view,
and they say,

490
00:29:50,980 --> 00:29:52,620
"I know how he could do it."

491
00:29:52,620 --> 00:29:55,460
Because it just inspires you.

492
00:29:57,700 --> 00:30:00,860
So how do you encapsulate Maxwell?
What is he for you?

493
00:30:00,860 --> 00:30:03,300
What do you think of him
more than anything else?

494
00:30:04,740 --> 00:30:07,780
What appealed to me about Maxwell

495
00:30:07,780 --> 00:30:10,820
is how normal he was,

496
00:30:10,820 --> 00:30:12,020
as a boy,

497
00:30:12,020 --> 00:30:14,540
that he loved outside.

498
00:30:14,540 --> 00:30:16,100
He loved the open air.

499
00:30:16,100 --> 00:30:18,580
He loved all the creatures.

500
00:30:18,580 --> 00:30:21,100
And the gardens and the trees
you see round here,

501
00:30:21,100 --> 00:30:23,020
thanks to Maxwell.

502
00:30:23,020 --> 00:30:25,660
But it's that emotional attachment
that you feel to him?

503
00:30:25,660 --> 00:30:30,300
Yes, it's the way he loved it here,
like I love it here.

504
00:30:30,300 --> 00:30:34,020
I've been offered lots and lots
of money to sell this place,

505
00:30:34,020 --> 00:30:36,140
but there's no way
they're going to get me out,

506
00:30:36,140 --> 00:30:37,220
except in a box.

507
00:30:40,700 --> 00:30:44,340
Like Duncan, Maxwell felt
a strong connection to Glenlair.

508
00:30:45,940 --> 00:30:49,060
His proposal poem to Katherine
had been about sharing their lives

509
00:30:49,060 --> 00:30:51,940
here - they'd even honeymooned
in Glenlair.

510
00:30:51,940 --> 00:30:56,340
When they returned here in 1860,
it wasn't just a holiday.

511
00:30:58,540 --> 00:30:59,980
On the death of his father,

512
00:30:59,980 --> 00:31:03,060
Maxwell had inherited
over 1,000 acres of farmland.

513
00:31:04,420 --> 00:31:07,620
Dozens of working people relied
on decisions he made.

514
00:31:08,820 --> 00:31:12,660
There were fields to sow, animals
to tend, buildings to construct.

515
00:31:14,820 --> 00:31:17,420
He raised funds to build a church

516
00:31:17,420 --> 00:31:19,660
and was keen to improve
local schooling.

517
00:31:21,740 --> 00:31:24,340
It was a responsibility
he took seriously.

518
00:31:24,340 --> 00:31:27,380
And every summer,
Maxwell and Katherine returned here

519
00:31:27,380 --> 00:31:28,780
to oversee the estate...

520
00:31:30,540 --> 00:31:33,820
..and recapture some of
the childhood peace he'd found here.

521
00:31:35,460 --> 00:31:38,140
But Maxwell wouldn't stay
at Glenlair.

522
00:31:38,140 --> 00:31:41,020
He wanted to be in the thick
of scientific research,

523
00:31:41,020 --> 00:31:43,260
and that meant a university.

524
00:31:45,020 --> 00:31:46,940
After a rejection from Edinburgh,

525
00:31:46,940 --> 00:31:50,820
he accepted a position
at King's College, London.

526
00:31:50,820 --> 00:31:54,020
Whilst there,
he would produce his finest work

527
00:31:54,020 --> 00:31:56,900
and unravel one of
the great mysteries of his age.

528
00:32:06,220 --> 00:32:09,420
Maxwell arrived in London
at the end of 1860

529
00:32:09,420 --> 00:32:11,780
and assumed teaching duties
immediately.

530
00:32:13,300 --> 00:32:15,980
While there,
he focused on a subject that had

531
00:32:15,980 --> 00:32:18,380
captured his attention
many years before.

532
00:32:20,420 --> 00:32:23,180
Ever since his early days
at Cambridge, Maxwell had been

533
00:32:23,180 --> 00:32:24,540
interested in electricity,

534
00:32:24,540 --> 00:32:27,540
after it was suggested as an area
to look at by a friend.

535
00:32:29,820 --> 00:32:32,100
That friend's advice was simple -

536
00:32:32,100 --> 00:32:35,300
if Maxwell wanted to learn
something about electricity,

537
00:32:35,300 --> 00:32:37,220
he needed to know Michael Faraday.

538
00:32:39,380 --> 00:32:42,900
Faraday was a self-taught
scientist who was revolutionising

539
00:32:42,900 --> 00:32:45,620
our understanding of electricity
and magnetism.

540
00:32:49,860 --> 00:32:51,900
Maxwell's relationship with him

541
00:32:51,900 --> 00:32:54,980
was one of the most fruitful
in 19th-century science.

542
00:32:58,380 --> 00:33:02,060
We'd known about electricity
and magnetism since ancient times.

543
00:33:03,260 --> 00:33:06,140
Most people had experienced
the power of electricity through

544
00:33:06,140 --> 00:33:07,940
terrifying lightning storms.

545
00:33:10,100 --> 00:33:13,380
And we'd used magnetism in ships'
compasses for centuries.

546
00:33:18,300 --> 00:33:20,540
They were considered
completely separate things

547
00:33:20,540 --> 00:33:23,060
for most of our history.

548
00:33:23,060 --> 00:33:25,060
But in the early 19th century,

549
00:33:25,060 --> 00:33:27,500
scientists like Faraday
were beginning to see

550
00:33:27,500 --> 00:33:29,780
a mysterious connection
between the two.

551
00:33:32,980 --> 00:33:35,580
Deep in the heart
of the Royal Institution,

552
00:33:35,580 --> 00:33:38,940
Faraday conducted experiments
to understand how they were linked.

553
00:33:44,100 --> 00:33:47,300
In one experiment,
a copper wire carrying electricity

554
00:33:47,300 --> 00:33:50,420
somehow provoked a nearby compass
to move.

555
00:33:52,660 --> 00:33:55,460
In another,
Faraday tried to do the opposite...

556
00:33:56,900 --> 00:34:00,060
..use a magnet to generate
electricity.

557
00:34:00,060 --> 00:34:02,020
Which led him to invent

558
00:34:02,020 --> 00:34:04,860
the electric generator,
which this is

559
00:34:04,860 --> 00:34:08,100
an example where you have
a permanent magnet and

560
00:34:08,100 --> 00:34:10,900
a coiled wire. So the wire's
wrapped around this bit.

561
00:34:10,900 --> 00:34:14,220
The wire's wrapped around
a cylinder, and you push and pull

562
00:34:14,220 --> 00:34:16,580
the magnet in and out
of the cylinder

563
00:34:16,580 --> 00:34:18,860
to generate an electric current.
I like the lights.

564
00:34:18,860 --> 00:34:20,580
What's the Christmas lights for,
then?

565
00:34:20,580 --> 00:34:23,380
Well, that's to show that
electricity's passing. Oh, OK.

566
00:34:25,420 --> 00:34:28,780
Faraday did NOT use light-emitting
diodes. I think he should have done.

567
00:34:28,780 --> 00:34:30,300
That was his great mistake!

568
00:34:30,300 --> 00:34:33,180
And all electricity power stations
throughout the world

569
00:34:33,180 --> 00:34:36,100
use this principle
of generating electricity

570
00:34:36,100 --> 00:34:38,780
that Faraday discovered down here
in 1831.

571
00:34:41,540 --> 00:34:44,620
Faraday had generated electricity
simply by moving a magnet

572
00:34:44,620 --> 00:34:46,860
through a coiled wire -

573
00:34:46,860 --> 00:34:50,220
a discovery that would forever
be associated with his name.

574
00:34:51,420 --> 00:34:53,860
But he was left with
perplexing questions.

575
00:34:55,260 --> 00:34:58,020
There was no physical contact
between the electric wire

576
00:34:58,020 --> 00:35:00,300
and the magnetic needle that moved

577
00:35:00,300 --> 00:35:03,380
nor between the moving magnet
and the copper coil.

578
00:35:04,780 --> 00:35:07,700
They were affecting each other
through seemingly thin air.

579
00:35:09,620 --> 00:35:11,420
But how could that be?

580
00:35:11,420 --> 00:35:13,940
Now, what Faraday thought was
happening was that there were

581
00:35:13,940 --> 00:35:19,540
lines of force coming out
of the end of the magnet,

582
00:35:19,540 --> 00:35:24,700
which were then cutting the wire
within the coil

583
00:35:24,700 --> 00:35:28,660
to move electricity around the coil.

584
00:35:28,660 --> 00:35:32,340
The idea of mysterious lines coming
out of the magnet to generate

585
00:35:32,340 --> 00:35:34,820
electricity may have seemed
outlandish,

586
00:35:34,820 --> 00:35:38,580
but Faraday had a simple experiment
that could prove their existence.

587
00:35:39,820 --> 00:35:42,820
So he took a very powerful,
permanent magnet.

588
00:35:44,060 --> 00:35:45,580
Placed some paper...

589
00:35:47,180 --> 00:35:48,220
..on it.

590
00:35:49,740 --> 00:35:53,500
Sprinkled iron filings over it.

591
00:35:56,860 --> 00:36:01,340
Just to represent
the lines of force...

592
00:36:01,340 --> 00:36:04,500
It never fails to impress, that,
does it? ..of the magnet.

593
00:36:04,500 --> 00:36:07,860
And you can see the sort of three
dimensional structure. Yeah, yeah.

594
00:36:07,860 --> 00:36:10,700
So these are coming up here
and swinging around... That's right.

595
00:36:10,700 --> 00:36:12,420
..and then coming down
into this bit here.

596
00:36:12,420 --> 00:36:17,700
And Faraday sort of made permanent
examples of this and sent them round

597
00:36:17,700 --> 00:36:20,540
to all his mates in Europe,
to show that space had structure

598
00:36:20,540 --> 00:36:24,380
as a very strong argument
for his field theory.

599
00:36:24,380 --> 00:36:27,380
So Faraday thought there was an
invisible force field at work here?

600
00:36:27,380 --> 00:36:32,500
Well, literally a field.
Faraday brings the world field

601
00:36:32,500 --> 00:36:35,140
into science.
And it's invisible, as you say.

602
00:36:35,140 --> 00:36:38,260
So this is why this is just
a representation that shows

603
00:36:38,260 --> 00:36:42,340
the existence of those
invisible lines. Yes, absolutely.

604
00:36:46,260 --> 00:36:48,980
Faraday's iron filings
experiment revealed

605
00:36:48,980 --> 00:36:52,620
the existence of an invisible field
stretching out into thin air.

606
00:36:54,860 --> 00:36:56,500
These fields, he thought,

607
00:36:56,500 --> 00:36:59,780
were responsible for
the experimental results he'd seen.

608
00:37:03,180 --> 00:37:05,140
Despite having physical proof,

609
00:37:05,140 --> 00:37:08,700
Faraday lacked a mathematical
description of how the field

610
00:37:08,700 --> 00:37:11,660
was generated
or why it affected things around it.

611
00:37:15,220 --> 00:37:17,500
Without a mathematical proof,

612
00:37:17,500 --> 00:37:22,580
many 19th-century scientists
dismissed the theory as speculative.

613
00:37:22,580 --> 00:37:25,580
But Maxwell had followed
Faraday's work for years...

614
00:37:25,580 --> 00:37:27,940
and set out to prove him right.

615
00:37:32,420 --> 00:37:35,260
Maxwell had plenty of time
to mull over the problem.

616
00:37:42,860 --> 00:37:45,100
The walk from his Kensington home
to King's College

617
00:37:45,100 --> 00:37:47,300
was an eight-mile round trip
every day.

618
00:37:48,580 --> 00:37:51,300
And during the walk,
he allowed his mind to wander.

619
00:37:52,980 --> 00:37:56,140
On those walks -
and at work - he had company.

620
00:37:57,700 --> 00:38:00,060
Apparently, Maxwell always had a dog.

621
00:38:00,060 --> 00:38:02,300
And he always called it
the same name!

622
00:38:02,300 --> 00:38:06,140
From childhood onwards,
every dog was called Toby.

623
00:38:06,140 --> 00:38:09,660
And Toby - whichever one it was -
rarely left his side.

624
00:38:11,220 --> 00:38:14,460
Toby was a constant companion
at home and in the lab.

625
00:38:14,460 --> 00:38:16,500
It's a sign of Maxwell's eccentricity

626
00:38:16,500 --> 00:38:18,620
that he would talk to Toby.

627
00:38:18,620 --> 00:38:20,220
He said he liked his company.

628
00:38:21,580 --> 00:38:25,820
During his walks to and from work,
Maxwell - and perhaps Toby -

629
00:38:25,820 --> 00:38:29,260
brooded over the mysterious
relationship between electricity

630
00:38:29,260 --> 00:38:30,420
and magnetism.

631
00:38:36,300 --> 00:38:39,460
His aim was to provide
a mathematical explanation

632
00:38:39,460 --> 00:38:40,940
for the link between the two.

633
00:38:43,980 --> 00:38:45,620
After years of thinking -

634
00:38:45,620 --> 00:38:47,580
and who knows
how many miles walking -

635
00:38:47,580 --> 00:38:49,540
he came up with a set of equations

636
00:38:49,540 --> 00:38:53,460
that described the relationship
between electricity and magnetism.

637
00:38:55,340 --> 00:38:58,940
Equations that would change
our lives forever.

638
00:38:58,940 --> 00:39:01,380
Sorry, Frank,
but this is just gobbledygook to me.

639
00:39:01,380 --> 00:39:04,020
I'm just looking at it trying
to make sense of it.

640
00:39:04,020 --> 00:39:06,380
Well, it's not much easier for me.
I mean...

641
00:39:06,380 --> 00:39:09,260
That's what he wrote first of all.
And looking at these,

642
00:39:09,260 --> 00:39:11,540
they probably mean little more to me
than to you.

643
00:39:11,540 --> 00:39:12,980
But 20 years later,

644
00:39:12,980 --> 00:39:16,180
they were written in a simpler
form which is the way that this...

645
00:39:16,180 --> 00:39:18,460
This form here.
That looks more manageable.

646
00:39:18,460 --> 00:39:21,980
But it still looks a bit confusing.
Could you take us through it, then?

647
00:39:21,980 --> 00:39:26,260
Right. Well, the first one says that
if you've got an electric charge,

648
00:39:26,260 --> 00:39:29,020
it spreads an electric field
out all over space.

649
00:39:30,300 --> 00:39:32,420
Just like his work
on Saturn's rings,

650
00:39:32,420 --> 00:39:35,700
each equation is a mathematical
description of something

651
00:39:35,700 --> 00:39:37,340
observed in the real world.

652
00:39:39,580 --> 00:39:43,140
So the first equation described
how a static electric charge

653
00:39:43,140 --> 00:39:44,820
generates an electric field.

654
00:39:49,340 --> 00:39:53,300
And the second, that magnetic poles
always come in pairs.

655
00:39:54,860 --> 00:39:58,820
The third equation describes
how a changing magnetic field

656
00:39:58,820 --> 00:40:00,420
generates an electric field.

657
00:40:03,060 --> 00:40:04,620
And the fourth equation,

658
00:40:04,620 --> 00:40:08,820
that an electric current surrounds
itself with a magnetic field.

659
00:40:08,820 --> 00:40:12,860
But Maxwell realised
there was something missing.

660
00:40:12,860 --> 00:40:17,780
Maxwell's genius was to realise
that each of these equations is fine

661
00:40:17,780 --> 00:40:19,700
until you put them together. Mm-hm.

662
00:40:19,700 --> 00:40:21,780
And then he realised
something was missing,

663
00:40:21,780 --> 00:40:23,460
and it was in this final equation.

664
00:40:23,460 --> 00:40:26,500
He said,
"There has to be another term."

665
00:40:31,060 --> 00:40:33,340
And what this extra piece says

666
00:40:33,340 --> 00:40:37,380
is if an electric field is changing,

667
00:40:37,380 --> 00:40:39,700
it will surround itself
with a magnetic field.

668
00:40:39,700 --> 00:40:42,980
Right. Which is like the sort
of mirror of this equation,

669
00:40:42,980 --> 00:40:45,940
which says if a magnetic
field is changing,

670
00:40:45,940 --> 00:40:48,460
it will surround itself
with an electric field.

671
00:40:48,460 --> 00:40:51,740
So, just take these two together and
just think about it for a second.

672
00:40:51,740 --> 00:40:53,780
If I've got a magnetic field
changing,

673
00:40:53,780 --> 00:40:55,780
it surrounds itself
with an electric.

674
00:40:55,780 --> 00:40:58,380
If the electric is changing,
it surrounds itself with

675
00:40:58,380 --> 00:41:00,700
a magnetic. And if that is changing,

676
00:41:00,700 --> 00:41:03,260
it will surround itself again
with an electric, and so on.

677
00:41:03,260 --> 00:41:05,700
Faraday to Maxwell,
electric to magnetic back and forth,

678
00:41:05,700 --> 00:41:08,580
back and forth. So there's a
coupling, basically, between the two.

679
00:41:12,900 --> 00:41:16,660
Maxwell's equations were saying
that electric and magnetic fields

680
00:41:16,660 --> 00:41:18,260
were inextricably linked.

681
00:41:19,500 --> 00:41:22,060
Changes in one created
changes in the other.

682
00:41:26,140 --> 00:41:28,620
It helped explain so much.

683
00:41:28,620 --> 00:41:31,060
When Faraday moved his magnet,

684
00:41:31,060 --> 00:41:33,740
he'd changed the position
of the magnetic field,

685
00:41:33,740 --> 00:41:35,900
and this triggered an electric field

686
00:41:35,900 --> 00:41:38,620
which caused electricity
to flow through the wire.

687
00:41:40,220 --> 00:41:42,420
And when electricity passed
through a wire,

688
00:41:42,420 --> 00:41:44,820
it wrapped a magnetic field
around it,

689
00:41:44,820 --> 00:41:46,820
causing the compass needle to move.

690
00:41:51,020 --> 00:41:55,100
Using pure maths,
Maxwell had unified electricity

691
00:41:55,100 --> 00:41:56,420
and magnetism

692
00:41:56,420 --> 00:41:59,580
and shown they were
two aspects of the same thing -

693
00:41:59,580 --> 00:42:02,300
a single electromagnetic field.

694
00:42:05,980 --> 00:42:08,620
This alone would have guaranteed
Maxwell's entry

695
00:42:08,620 --> 00:42:10,860
to the scientists hall of fame.

696
00:42:10,860 --> 00:42:13,700
He could have rested on his laurels.

697
00:42:13,700 --> 00:42:17,220
But whether it was his natural
curiosity or the long walks

698
00:42:17,220 --> 00:42:19,820
with Toby, he didn't stop there.

699
00:42:19,820 --> 00:42:23,300
He used his equations to test
another of Faraday's ideas.

700
00:42:25,500 --> 00:42:28,140
Faraday had guessed that
under certain circumstances,

701
00:42:28,140 --> 00:42:31,820
the electric and magnetic field lines
could be disturbed by waves

702
00:42:31,820 --> 00:42:34,060
travelling along them -

703
00:42:34,060 --> 00:42:36,500
almost like ripples
on the surface of water.

704
00:42:42,900 --> 00:42:45,740
Maxwell used his equations
to show that the fields

705
00:42:45,740 --> 00:42:48,180
could fluctuate in time
with each other

706
00:42:48,180 --> 00:42:53,380
and cause what Maxwell called
an electromagnetic wave.

707
00:42:53,380 --> 00:42:56,180
He could even measure
the speed of the wave.

708
00:42:56,180 --> 00:43:00,620
This says the electromagnetic wave
travels through space.

709
00:43:00,620 --> 00:43:02,980
And buried in here,

710
00:43:02,980 --> 00:43:07,260
he was able to extract the speed
that the wave travels.

711
00:43:07,260 --> 00:43:10,260
And when he put the numbers in,
from things that Faraday and others

712
00:43:10,260 --> 00:43:13,420
had already measured, he worked out
the speed and it came out as

713
00:43:13,420 --> 00:43:16,820
a phenomenal 300,000 kilometres
every second, roughly.

714
00:43:17,980 --> 00:43:22,380
And that, I think, is the moment
of discovery because he knew

715
00:43:22,380 --> 00:43:25,060
that people had measured
the speed of light,

716
00:43:25,060 --> 00:43:27,260
which was 300,000 kilometres
every second.

717
00:43:27,260 --> 00:43:28,780
Now, at this moment you think,

718
00:43:28,780 --> 00:43:32,300
is this a coincidence or are these
equations telling me something?
Yeah.

719
00:43:32,300 --> 00:43:34,300
And, of course,
they're telling you something,

720
00:43:34,300 --> 00:43:38,260
and what the message is -
light is an electromagnetic wave.

721
00:43:40,300 --> 00:43:42,460
This was a stunning conclusion.

722
00:43:45,620 --> 00:43:48,420
Maxwell had explained
what light itself was.

723
00:43:49,820 --> 00:43:53,340
At the same time, he'd introduced
something new to science -

724
00:43:53,340 --> 00:43:58,340
electromagnetic waves - and they
were destined to change our planet.

725
00:44:01,780 --> 00:44:04,220
The problem was
he hadn't physically demonstrated

726
00:44:04,220 --> 00:44:06,780
the existence of these waves.

727
00:44:06,780 --> 00:44:09,100
It was all in the maths.

728
00:44:09,100 --> 00:44:11,620
Physical proof
would have to come later.

729
00:44:12,860 --> 00:44:15,700
His equations were
an astonishing piece of work,

730
00:44:15,700 --> 00:44:17,940
packed with radical ideas.

731
00:44:19,060 --> 00:44:22,340
Maxwell gave us a unified theory
of electricity and magnetism,

732
00:44:22,340 --> 00:44:26,380
he solved the mystery of what light
was and he predicted the existence

733
00:44:26,380 --> 00:44:30,460
of these invisible fields that would
directly affect our life.

734
00:44:30,460 --> 00:44:34,420
That's difficult enough to grasp
for a 21st-century scientist,

735
00:44:34,420 --> 00:44:36,940
but what on earth did
the Victorians think?

736
00:44:39,500 --> 00:44:43,300
The fact is Maxwell was asking
a lot from his peers.

737
00:44:43,300 --> 00:44:46,060
Invisible fields, undetected waves,

738
00:44:46,060 --> 00:44:47,700
dense maths -

739
00:44:47,700 --> 00:44:51,380
it was all a bit much
for 19th-century scientists.

740
00:44:51,380 --> 00:44:55,500
Ironically, Maxwell found himself
in a similar position to Faraday -

741
00:44:55,500 --> 00:44:58,260
surrounded by sceptical colleagues

742
00:44:58,260 --> 00:45:01,740
and lacking the proof
to vindicate his theory.

743
00:45:01,740 --> 00:45:04,420
But a jubilant Maxwell
was undeterred -

744
00:45:04,420 --> 00:45:06,820
he wrote an excited letter
to his cousin.

745
00:45:08,020 --> 00:45:10,060
"I also have a paper afloat, with

746
00:45:10,060 --> 00:45:12,420
"an electromagnetic theory of light,

747
00:45:12,420 --> 00:45:16,620
"which until I'm convinced to the
contrary, I hold to be great guns."

748
00:45:18,420 --> 00:45:20,020
The guns may have fired,

749
00:45:20,020 --> 00:45:22,860
but it would be a while
before they would be heard.

750
00:45:22,860 --> 00:45:26,060
It took more than 20 years
before a German scientist called

751
00:45:26,060 --> 00:45:31,220
Heinrich Hertz found physical proof
for electromagnetic waves.

752
00:45:31,220 --> 00:45:33,380
When he was asked what
practical use the wave had,

753
00:45:33,380 --> 00:45:35,980
he replied,
"It's of no use whatsoever.

754
00:45:35,980 --> 00:45:40,180
"This is just an experiment that
proves Maestro Maxwell was right."

755
00:45:45,220 --> 00:45:48,900
How wrong he was, because Hertz
had discovered radio waves.

756
00:45:50,100 --> 00:45:52,940
Marconi invented the radio,
and since then, we've been

757
00:45:52,940 --> 00:45:56,820
using them to spread radio
and television all over the planet.

758
00:45:56,820 --> 00:46:00,300
But this was just the first in a long
list of discoveries.

759
00:46:00,300 --> 00:46:04,100
# Happy days are here again... #

760
00:46:04,100 --> 00:46:08,060
Using higher frequency radio waves,
we developed radar,

761
00:46:08,060 --> 00:46:12,340
which now gets used in everything
from aviation to geology.

762
00:46:12,340 --> 00:46:15,300
Microwaves were discovered,
which we use in cooking

763
00:46:15,300 --> 00:46:17,260
and when we use a mobile phone.

764
00:46:17,260 --> 00:46:19,660
Infrared is used in thermal imaging

765
00:46:19,660 --> 00:46:22,580
and in most TV remote controls.

766
00:46:22,580 --> 00:46:24,900
Ultraviolet is used
in fluorescent lamps,

767
00:46:24,900 --> 00:46:27,860
security marking
and medical research.

768
00:46:27,860 --> 00:46:31,500
X-rays have provided us
with a valuable medical tool,

769
00:46:31,500 --> 00:46:34,140
but more recently in security.

770
00:46:34,140 --> 00:46:35,860
And gamma rays have been used to

771
00:46:35,860 --> 00:46:39,860
detect and treat cancer, and even
to sterilise the food we eat.

772
00:46:41,420 --> 00:46:43,260
All these things are connected.

773
00:46:44,540 --> 00:46:47,300
Maxwell had shown that light
and the colours we see

774
00:46:47,300 --> 00:46:49,820
are electromagnetic waves.

775
00:46:49,820 --> 00:46:52,860
But he predicted
there would be more.

776
00:46:52,860 --> 00:46:56,340
Today, we know that visible light
is just a tiny sliver

777
00:46:56,340 --> 00:46:59,140
of a broad spectrum of
electromagnetic waves.

778
00:47:00,580 --> 00:47:01,940
And by understanding

779
00:47:01,940 --> 00:47:03,300
and exploiting them,

780
00:47:03,300 --> 00:47:05,460
we've revolutionised our world,

781
00:47:05,460 --> 00:47:07,060
all thanks to equations

782
00:47:07,060 --> 00:47:10,140
Maxwell published 150 years ago.

783
00:47:15,180 --> 00:47:17,820
That was all part of a future
that Maxwell wouldn't see.

784
00:47:19,540 --> 00:47:23,500
When he first published,
people didn't understand him.

785
00:47:23,500 --> 00:47:28,460
You know, back in 1865, there was no
sign, no evidence of these mysterious

786
00:47:28,460 --> 00:47:30,420
electromagnetic waves.

787
00:47:30,420 --> 00:47:34,060
Maxwell was asking people to believe
that these waves could pass

788
00:47:34,060 --> 00:47:38,100
through empty space
and affect things at a distance.

789
00:47:38,100 --> 00:47:40,180
It was just too much to ask.

790
00:47:40,180 --> 00:47:44,780
His equations were initially met
with a bewildered silence.

791
00:47:44,780 --> 00:47:46,900
19th-century scientists were used to

792
00:47:46,900 --> 00:47:49,460
thinking of the world
in mechanical terms -

793
00:47:49,460 --> 00:47:53,500
physically tangible objects that
could be touched, measured and felt.

794
00:47:54,940 --> 00:47:57,860
Flying in the face of that
was Maxwell's theory -

795
00:47:57,860 --> 00:47:59,460
based on dense mathematics,

796
00:47:59,460 --> 00:48:02,420
invisible fields
and undetected waves.

797
00:48:03,820 --> 00:48:05,860
Many thought Maxwell's theory

798
00:48:05,860 --> 00:48:09,220
was a kind of abstract mathematical
speculation.

799
00:48:09,220 --> 00:48:13,060
That he had strayed too far
from physical reality.

800
00:48:13,060 --> 00:48:17,300
That he was, in essence,
away with the fairies.

801
00:48:17,300 --> 00:48:19,860
Maxwell became convinced
that he had to develop his theory

802
00:48:19,860 --> 00:48:22,140
of magnetism and electricity.

803
00:48:22,140 --> 00:48:24,060
Not long after that publication,

804
00:48:24,060 --> 00:48:26,220
he decided to pursue
his own interests

805
00:48:26,220 --> 00:48:28,540
and resigned his post at King's.

806
00:48:28,540 --> 00:48:29,940
He was going home.

807
00:48:38,100 --> 00:48:41,780
After the lukewarm reaction
to his 1865 publication,

808
00:48:41,780 --> 00:48:45,140
the comfort of Glenlair was welcome.

809
00:48:45,140 --> 00:48:49,140
Ever industrious, Maxwell produced
papers on thermodynamics

810
00:48:49,140 --> 00:48:51,260
and even topology.

811
00:48:51,260 --> 00:48:54,340
But always he returned
to his electromagnetic theory,

812
00:48:54,340 --> 00:48:55,660
slowly refining it.

813
00:48:58,180 --> 00:49:02,820
After six years in the wilderness,
Cambridge University approached him.

814
00:49:02,820 --> 00:49:08,180
They wanted someone to plan and run
a lab in Experimental Physics.

815
00:49:08,180 --> 00:49:11,300
Despite all his achievements,
Maxwell was third in line,

816
00:49:11,300 --> 00:49:14,220
after two other candidates
had rejected the offer.

817
00:49:20,020 --> 00:49:23,300
In 1871, he left Glenlair
for Cambridge,

818
00:49:23,300 --> 00:49:26,460
where he designed and built
the Cavendish Laboratory,

819
00:49:26,460 --> 00:49:29,580
which would be responsible
for discoveries that shaped physics

820
00:49:29,580 --> 00:49:31,020
in the 20th century.

821
00:49:33,340 --> 00:49:35,060
And as its first director,

822
00:49:35,060 --> 00:49:39,300
his open-minded approach set
the tone for subsequent generations.

823
00:49:40,740 --> 00:49:41,900
"I never try to dissuade

824
00:49:41,900 --> 00:49:44,100
"a man from trying an experiment.

825
00:49:44,100 --> 00:49:45,300
"If he does not find out

826
00:49:45,300 --> 00:49:46,580
"what he wants,

827
00:49:46,580 --> 00:49:48,980
"he may find out something else."

828
00:49:52,700 --> 00:49:55,660
The Cavendish Lab would become
a phenomenal success.

829
00:49:58,620 --> 00:50:01,540
It's within these walls that
we discovered the electron

830
00:50:01,540 --> 00:50:03,140
and later on the neutron.

831
00:50:05,220 --> 00:50:09,060
Watson and Crick were working here
when, in 1953,

832
00:50:09,060 --> 00:50:11,900
X-rays were used to show
the structure of DNA.

833
00:50:14,700 --> 00:50:18,500
The Cavendish is now widely regarded
as a centre of excellence,

834
00:50:18,500 --> 00:50:21,580
and it's produced 29 Nobel Prize
winners to date.

835
00:50:25,460 --> 00:50:28,740
But every summer,
Maxwell returned to Glenlair,

836
00:50:28,740 --> 00:50:31,220
patiently working out
the full implications

837
00:50:31,220 --> 00:50:33,460
of his electromagnetic theory
of light.

838
00:50:42,980 --> 00:50:45,940
In 1873, Maxwell released

839
00:50:45,940 --> 00:50:49,700
a dynamical theory of electricity
and magnetism.

840
00:50:52,740 --> 00:50:56,100
The intervening years had allowed
his colleagues time to digest

841
00:50:56,100 --> 00:50:59,900
his theory, and it was starting
to gain traction.

842
00:50:59,900 --> 00:51:02,420
But he wouldn't live to see
it vindicated.

843
00:51:03,660 --> 00:51:06,500
When guests were visiting
Glenlair in 1879,

844
00:51:06,500 --> 00:51:10,500
Maxwell found he could barely walk
down to the river, such was the pain.

845
00:51:11,540 --> 00:51:13,660
The pain was in his stomach.

846
00:51:13,660 --> 00:51:14,900
In October of that year,

847
00:51:14,900 --> 00:51:17,980
he was diagnosed
with abdominal cancer,

848
00:51:17,980 --> 00:51:19,140
given a month to live.

849
00:51:28,460 --> 00:51:31,340
Maxwell was just 48
when he received the news.

850
00:51:33,980 --> 00:51:37,900
He knew his mother had died at
the same age, from the same disease.

851
00:51:44,740 --> 00:51:47,260
Nevertheless, he accepted his fate

852
00:51:47,260 --> 00:51:50,140
with the calm stoicism
that had defined his life.

853
00:51:52,860 --> 00:51:55,380
Katherine nursed him
as best she could.

854
00:51:55,380 --> 00:51:59,300
It's said that on his deathbed,
Maxwell breathed deeply,

855
00:51:59,300 --> 00:52:02,540
and with a long look at his wife,
passed away.

856
00:52:10,620 --> 00:52:14,420
James Clerk Maxwell
died in November 1879.

857
00:52:16,220 --> 00:52:18,260
He was buried in Parton Kirk,

858
00:52:18,260 --> 00:52:22,140
his childhood church, just a few
miles from his beloved Glenlair.

859
00:52:32,860 --> 00:52:35,940
He lies in a modest grave
next to his parents.

860
00:52:35,940 --> 00:52:39,260
And seven years later, Katherine
would be buried next to him.

861
00:52:43,340 --> 00:52:45,620
Apart from a plaque
outside the cemetery,

862
00:52:45,620 --> 00:52:48,260
there's nothing to mark
this grave as different

863
00:52:48,260 --> 00:52:50,020
from any of the others.

864
00:52:50,020 --> 00:52:52,460
There's no list
of grand achievements.

865
00:52:52,460 --> 00:52:56,860
It's just simple and modest,
like the man himself.

866
00:53:01,940 --> 00:53:04,300
A visitor could be forgiven
for passing the grave

867
00:53:04,300 --> 00:53:06,580
without a second glance.

868
00:53:06,580 --> 00:53:09,820
But for some,
this is a special place.

869
00:53:14,380 --> 00:53:17,580
There is a story that is told
around Parton Kirk.

870
00:53:17,580 --> 00:53:21,060
Shortly after the fall of the
Berlin Wall, two buses arrived,

871
00:53:21,060 --> 00:53:23,700
and people filed into the graveyard.

872
00:53:25,100 --> 00:53:27,220
A curious local asked who they were.

873
00:53:27,220 --> 00:53:30,660
They were, they said,
Russian scientists who had travelled

874
00:53:30,660 --> 00:53:33,820
to visit the grave of
Scotland's Einstein.

875
00:53:36,060 --> 00:53:39,820
You know, Maxwell died
at a relatively young age, 48,

876
00:53:39,820 --> 00:53:44,660
which even by the standards
of his day, was an untimely death.

877
00:53:44,660 --> 00:53:46,180
And you just wonder,

878
00:53:46,180 --> 00:53:49,140
given the achievements
that he had in his lifetime,

879
00:53:49,140 --> 00:53:53,380
what he would have conjured up
if he'd lived until he was 60 or 70.

880
00:53:54,660 --> 00:53:58,020
Maxwell may not have been fully
appreciated in his time,

881
00:53:58,020 --> 00:54:01,020
but in the decades following
his death, scientists started

882
00:54:01,020 --> 00:54:02,380
to recognise his genius.

883
00:54:09,540 --> 00:54:11,740
Eight years after Maxwell's death,

884
00:54:11,740 --> 00:54:14,220
Heinrich Hertz discovered
radio waves,

885
00:54:14,220 --> 00:54:18,180
proving beyond doubt the existence
of electromagnetic waves.

886
00:54:22,620 --> 00:54:25,020
The rest, as they say, is history.

887
00:54:26,380 --> 00:54:30,020
Over a century later,
these waves have changed our planet

888
00:54:30,020 --> 00:54:32,420
and are part of our everyday lives.

889
00:54:36,980 --> 00:54:39,740
But focusing on the technological
results of his work

890
00:54:39,740 --> 00:54:42,420
diminishes its importance,

891
00:54:42,420 --> 00:54:46,260
because he changed the way
we understand reality itself.

892
00:54:46,260 --> 00:54:47,740
Before the work

893
00:54:47,740 --> 00:54:49,900
of Maxwell,
and Faraday just before him,

894
00:54:49,900 --> 00:54:52,420
the experiments,
we understood the world in terms

895
00:54:52,420 --> 00:54:53,860
of springs and cogs,

896
00:54:53,860 --> 00:54:55,340
a machine-like world.

897
00:54:55,340 --> 00:55:00,140
And that machine-like world
was pretty primitive.

898
00:55:00,140 --> 00:55:04,540
What Maxwell's work showed
is that the way that we understand

899
00:55:04,540 --> 00:55:08,340
the interaction between
material bodies is via

900
00:55:08,340 --> 00:55:11,820
this idea of a field, not the sort
of field we're standing in.

901
00:55:11,820 --> 00:55:16,020
Not a green field? Not a green field
but something that penetrates

902
00:55:16,020 --> 00:55:20,460
space and which really governs
the way that the world behaves.

903
00:55:23,700 --> 00:55:27,220
Maxwell helped overthrow
the mechanical model of the universe

904
00:55:27,220 --> 00:55:29,900
that physicists
had held since Newton

905
00:55:29,900 --> 00:55:32,020
and issued in a new era.

906
00:55:33,860 --> 00:55:37,100
We now think of all the forces
in the universe interacting

907
00:55:37,100 --> 00:55:40,260
through fields
rather than direct physical contact.

908
00:55:43,220 --> 00:55:46,580
This was a crucial shift
in our understanding,

909
00:55:46,580 --> 00:55:50,540
prompting Einstein to say,
"One scientific epoch ended

910
00:55:50,540 --> 00:55:53,980
"and another began
with James Clerk Maxwell."

911
00:55:57,500 --> 00:56:01,580
Which is, perhaps, why he's still
revered by scientists today.

912
00:56:08,500 --> 00:56:12,380
This meeting we're having here
in Edinburgh today is very special.

913
00:56:12,380 --> 00:56:14,100
We're celebrating

914
00:56:14,100 --> 00:56:17,260
the 150th anniversary of Maxwell's

915
00:56:17,260 --> 00:56:20,300
publication of his equations
of electromagnetism.

916
00:56:21,900 --> 00:56:25,940
Some of Britain's finest scientists
gather at an event to remember

917
00:56:25,940 --> 00:56:28,500
the life and work of
James Clerk Maxwell.

918
00:56:29,580 --> 00:56:31,460
Maxwell is all around us.

919
00:56:32,940 --> 00:56:35,060
Every single piece of technology

920
00:56:35,060 --> 00:56:36,460
that is around us today -

921
00:56:36,460 --> 00:56:38,260
computing, fibre optics,

922
00:56:38,260 --> 00:56:42,140
cameras, mobile phones,
everything depends

923
00:56:42,140 --> 00:56:45,260
on extensions
of those Maxwell's equations.

924
00:56:46,700 --> 00:56:50,260
Without those,
we wouldn't be where we are today.

925
00:56:50,260 --> 00:56:53,500
Even the internet
doesn't exist without them.

926
00:56:53,500 --> 00:56:56,780
Maxwell changed the way
we think forever.

927
00:57:00,580 --> 00:57:04,260
'You can't overestimate
his contribution,

928
00:57:04,260 --> 00:57:06,420
'his influence on everything,

929
00:57:06,420 --> 00:57:09,180
'both practical and theoretical.'

930
00:57:09,180 --> 00:57:13,180
He is the most remarkable Scot,
intellectually,

931
00:57:13,180 --> 00:57:14,780
that has ever arisen.

932
00:57:14,780 --> 00:57:16,180
No question about it.

933
00:57:17,500 --> 00:57:21,900
In terms of the sequence
of the great men of physics,

934
00:57:21,900 --> 00:57:24,300
starting with Galileo and Newton,

935
00:57:24,300 --> 00:57:26,460
then comes Maxwell

936
00:57:26,460 --> 00:57:28,260
and then Einstein,

937
00:57:28,260 --> 00:57:30,460
who said that

938
00:57:30,460 --> 00:57:35,420
Maxwell was the greatest physicist
after Newton.

939
00:57:35,420 --> 00:57:38,700
It's wonderful to be sitting
in the audience of a meeting

940
00:57:38,700 --> 00:57:42,660
surrounded by Nobel Prize winners,
the great and the good.

941
00:57:42,660 --> 00:57:47,820
There's a sense of shared excitement
that you...

942
00:57:47,820 --> 00:57:51,700
This unapologetic geekiness
that however much...

943
00:57:51,700 --> 00:57:54,060
You know, people like Peter Higgs

944
00:57:54,060 --> 00:57:57,500
and Nobel Prize winners,
we are still in awe

945
00:57:57,500 --> 00:57:59,260
of this giant of physics.

946
00:58:01,100 --> 00:58:04,780
And having got to know the man,
I can understand why.

947
00:58:06,060 --> 00:58:09,660
I can't blame people for not knowing
about James Clerk Maxwell -

948
00:58:09,660 --> 00:58:12,140
this is difficult stuff!

949
00:58:12,140 --> 00:58:14,620
I just think that, given
the breadth of his discoveries

950
00:58:14,620 --> 00:58:17,180
and the sheer impact they've had,
it's a travesty

951
00:58:17,180 --> 00:58:19,700
that Maxwell's name's not up there
with Newton and Einstein

952
00:58:19,700 --> 00:58:21,740
as one of the greats.

953
00:58:21,740 --> 00:58:26,460
Maxwell is Scotland's Einstein,
and we should remember him as such.