All language subtitles for Bbc.men.of.rock.S01E01.MVGroup.org.English-WWW.MY-SUBS.CO

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Whoo hoo!

I'm here!

This is it.

There's the top just there.

Ah, this is fantastic! What a view!

I'm back.

I was last here 25 years ago.

25 years!

And somewhere around here
I left my hammer.

Ah, look at this! Here we are!

Whoo!

Would you look at this?

Look at this view.
This is what I remember.

This is our ancient heritage
laid out before our very eyes.

Scotland's landscape
has an epic and violent past.

Hidden in these mountains and glens
is the history of the planet.

I'm going to show you
how this landscape was used

by a bunch of brilliant, maverick, eccentric
scientists to solve the greatest mysteries of the Earth.

I'm following in the footsteps
of these pioneers

who blazed a trail
where no-one had been before.

They showed vision and
determination...

.. to piece together baffling
evidence

and uncover the forces
that shape our world.

Wow! God, that's so hot!

It's all out there
if you know what to look for.

Written into the Scottish landscape
is the story of the entire planet.

The remote
northwest Highlands of Scotland.

If feels like the ends of the Earth.

For centuries, people have looked
at this landscape

and wondered how long it's been here
and how it was formed.

It wasn't until the 1750s that the answer
began to emerge, from myth and superstition

towards a new view of the Earth
based on science.

One man had a revolutionary new
idea that changed everything -

changed the way we thought about the planet,
even about the way we thought about ourselves.

The man who started this scientific revolution
grew up in Scotland's capital, Edinburgh.

James Hutton was to become
the founding father of geology.

As a young man,
the hills around his home city

made him curious about how
the Earth was formed.

Hutton used to come up here a lot.

He would have made a fantastic
travelling companion.

He was funny, bawdy, a bit rude.

He liked his whisky, liked his women,
and he loved debating new ideas.

In 1747, Hutton was
a young medical graduate

with an unusually broad interest
in the whole natural world.

When he studied the
origins of the landscape,

he found that the accepted authority
was not science but theology.

When Hutton started
to think about the Earth,

there really was only geology
textbook available - the Bible.

What I love about this edition
from Hutton's time

is it gives a date for when God
created the Earth and the seas.

Before Christ 4004.

Not just in 4004BC, but on Saturday
the 22nd October, 4004BC.

Hutton believed in God.

But unusually for a man of his time,

he was not committed to a literal
interpretation of the Bible.

He believed that God had created a
world that had a system of natural laws.

But he didn't particularly dwell
on these ideas.

Instead, he did what many
students do. He got drunk.

He was also getting seriously
distracted by the ladies

and it was that
that would prove his downfall.

It was Hutton's relationship
with one particular woman

that seems to have led to heartache and to
his banishment from his beloved Edinburgh.

Hutton had got his young lover,
Miss Edington, pregnant.

This was a scandal. She was
rushed away to London to give birth.

To limit the damage to his family's
reputation, Hutton left Edinburgh.

At the age of 26, he was forced to make a new life
on a small disused family farm in southern Scotland.

Hutton wrote that it was,

"A cursed country where everything
conspires to break my heart. "

But it was this remote farm that would trigger
his brilliant insights about the planet.

Well, this is Slighhouses Farm
but...

what a landscape! It's bleak and
windswept and pretty soggy today.

Certainly not the kind of place
where you feel

that you would devise a major new
theory about the Earth as a system.

But that is exactly what Hutton did.

First, he had to turn this rain-drenched
landscape into a profitable working farm.

One of the dirty jobs he constantly faced
was to dig and clear drainage ditches.

Hard work!

'Denise Daly Walton farms nearby
and knows what he was up against. '

Well, the purpose of this ditch was
to carry the water off the field

but what's happened over time is
that the sediment, all the topsoil,

has run off the fields and has
actually blocked this up.

This is gold dust in terms of cultivated
land but it's wasted in these ditches. Agh!

Every year, Hutton
cleared these drainage ditches.

And every year, the rain washed the precious
topsoil off his fields into the ditches

and carried it downstream.

This burn draining through Hutton's
land was the start of a long journey

for all that soil washed
away from his fields.

The water flows down into larger
and larger streams and rivers

and of course where the water flows
the sand silt and mud follows,

eventually being dumped in the sea.

This incessant erosion of the land
seriously concerned Hutton

because he realised that
if all the soil was washed away,

then eventually there'd be nothing to grow
crops in and ultimately people would starve.

Hutton looked at this erosion
and realised it must happen

not just in Scotland,
but across the whole planet.

It appeared that God had made a world
that stripped farms of good soil.

Eventually, if this continued, there
would be an utterly barren landscape.

But to be honest,
Hutton just didn't buy that.

In his heart, it made no sense that
God would let his people starve.

And in his head, it made no sense that the
Earth would irreversibly wear away to nothing.

He was convinced that there had
to be a way to make new land.

Hutton still only 34 and working in isolation, had
come to reject the conventional view of the Earth.

He couldn't accept that the
world had been created by God

at a single stroke
and remained unchanged.

His radical thought was that God must have
designed a planet that could rebuild itself.

The question was,

how could new land be formed?

Hutton spotted something in the landscape
around his farm that gave him his first clue.

Hutton would have seen cliffs
like this all over the place.

If you look at this rock face, you see distinct
layers of rock, all of them subtly different.

Hundreds of them.

What Hutton realised was that these bands of
sediment were laid down at different times.

Flushed in from rivers and
deposited one on top of the other.

Just builds up over time,

year after year,

slowly compacting into rock.

Hutton's greatest idea - and
I guess it seems so obvious now -

is that the creation of land
and the destruction of land

are not sudden and dramatic events
in the dim and biblical past,

but slow and imperceptible actions
that are going on all the time.

They're going on right now.

The idea that land was created
from the rubble of the past

was a startling new way
to see the landscape.

And this sedimentary rock,

formed from layers of mud and sand
laid down on rivers and seas,

is found everywhere.

From the white cliffs
of England's south coast...

to America's Grand Canyon.

Hutton had made his
first breakthrough.

He was now sure there was a
great system driving the Earth.

After 15 years on the farm, Hutton was
about to start a new chapter in his life,

one that would test his ideas and
push him to even greater discoveries.

At the age of 41,
his years of exile were over.

He returned
to the city of his youth.

It was the time of the
Scottish Enlightenment.

Edinburgh was the
intellectual capital of the world.

Hutton made the most of being back.

All over town, he debates and drinks

with the greatest minds of his era.

You can see why these
gatherings were ideal for Hutton,

his personality a mix of
deep thinker and deep drinker.

This open convivial atmosphere was
perfect for him to air his big idea.

Mind you, even all this bonhomie wasn't enough
to paper over the cracks in Hutton's theory.

Hutton knew that not all the rocks he could
see had been laid down in layers of sediment.

If the Earth's system continually recycled all
land, what other ways could rocks be formed?

Hutton still had a large
piece of the jigsaw missing.

He got his inspiration from another
great mind of the Scottish Enlightenment.

His friend - an arguably more
famous James - James Watt.

Fellow Scotsman James Watt
was an accomplished inventor.

Famous for making steam engines
more efficient.

It was James Watt's
harnessing of heat

that would power the
Industrial Revolution.

Hutton had a thing about machines and he was
fascinated by Watt's steam-powered contraptions.

Hutton saw that heat
gave steam engines enormous power.

He began to wonder
if heat powered the planet.

Maybe heat within the Earth was a force
that could change and renew the landscape.

Perhaps the centre of the Earth
contained a mighty heat engine.

Scientists in the 1700s
had seen active volcanoes.

But they thought they were
only small, isolated fires.

Hutton was the first person to imagine that
the centre of the Earth was a molten ball.

He saw volcanoes as the vents of a
giant furnace deep in the Earth.

He believed that this furnace
had the power to create new land...

land that was born molten.

If he could prove that much of the
landscape had started out molten,

then he would have discovered
another way

in which the Earth
could continually renew itself.

The trouble was that if a lot of the rocks
started off molten, why were they all so different?

If they had the same origin, then
surely they would look the same?

If you were trying to define genius,

then I guess it would be about making remarkable
connections that no-one had ever considered before.

But time and time again, he got his ideas from farm
ditches, from local cliffs and from steam engines.

And perhaps his cleverest
piece of lateral thinking

was when he hears of an accident
in a glass bottle factory.

Next one...

Glass artist Siobhan Healy is going to help me
recreate the incident that caught Hutton's attention.

Something immensely satisfying
about this!

'At a glass factory in Edinburgh,

'the workers accidentally
left a batch of molten glass

'in the kiln too long. '

OK.

'We've got two piles
of broken glass.

'We'll treat one normally and use
the other to re-create the accident. '

So this is ready.

I'll just close it over.

That's us up to our top temperature.

It'll go completely molten at that
temperature, it goes like liquid.

So this one goes in the other
one, the slow one?

Yes, this one's going to be
substantially longer, this programme,

because everything will be exactly the
same apart from the rate of cooling.

The reason Hutton was so
interested in the results is because

he knew that molten glass would
behave in the same way as molten rock.

Wow! God, that's so hot.

So that is what 900 degrees
feels like? That's fantastic. Yeah.

Oh, that's so hot.
You just want to touch it -

I know it's the last thing
my fingers would do, but...

Oooh, scorchio. Scorchio.

'We have cooled the two samples
at different rates.

'The results are dramatic. '

This one here is what?

This is the vitrified piece of glass. This is the
one that cooled fast, quenched really fast. Yes.

You can see right through it, it's
beautifully transparent. Look at that.

But this is completely different. This is a
molten rock that's solidified really slowly.

So you can actually see the crystals
in here, little angular crystals,

and the texture's
completely different.

Crystals are formed inside the glass
or rock when atoms stick together.

It takes a long time for clusters of
atoms to grow big enough to be seen.

When glass cools quickly, the crystals
are very small and the glass is clear.

But when the workers left the glass
to cool down over a long period,

large crystals were created.

Hutton had an explanation for the many different
rock types we see on the earth's surface.

Very slow cooling
creates large crystals.

Faster cooling
creates smaller crystals,

like in this granite.

And rapid cooling
creates tiny crystals,

like in volcanic basalt.

All we've done is alter
how fast the molten glass cooled,

and we've created two completely
different materials from it.

Hutton grasped that a whole variety of
rocks could have started off as molten

and as they solidified
under different conditions

their appearance and look
would change.

This meant that heat could have formed far more
of the earth's surface than previously thought

and it convinced Hutton that there really
was a vast internal heat engine at work.

Hutton had come up with two fundamental
ways that land could be created.

Sedimentary rock
could form when weather -

rain, frost, and wind -

eroded the soil.

Rivers carried the sediment
to the oceans.

It was compressed to form new rock.

And his second idea?

That a hot core
in the centre of the earth

could create molten rock
which cooled to become land.

He had a clear vision of an earth
that destroyed and repaired itself

in an endless cycle.

Hutton's idea is so, so beautiful.

And amazingly for something that was
conceived nearly 250 years or so ago,

it's nearly all right.

It's a big, coherent,
impressive idea.

And this concept of the earth as a
system, continually self renewing,

well, it feels so modern.

But the big question was, back then,

was the world ready for it?

Hutton had to be persuaded by
friends to go public with his ideas.

He was worried about
how they would be received.

But in 1785, he presented his
theory of the earth as a system

at the Royal Society of Edinburgh.

Imagine the scene. In front of some
of the greatest scientists of the age,

the outsider Hutton prepares to
present his radical theory of the earth.

He's a terrible speaker, though,
he talks in a broad Scots accent.

And he's incredibly nervous.

What's more, he's got this nagging feeling that
he doesn't yet have enough evidence from the field

to back up his theory.

And he knows that what he's going
to say is really controversial.

His ideas go against all the
religious orthodoxy of the day.

In the event,
his worst fears are realised.

The presentation bombs.

The gentlemen of the Royal Society

rejected Hutton's theory
out of hand.

Worse for the God-fearing Hutton,

he was accused of being an atheist.

One of the biggest upsets
was about this stuff - granite.

It's hard to believe that this
could cause even mild disagreement.

But it produced
a most almighty stink.

The accepted wisdom was that granite was
the first part of earth to be created by God.

Nothing could be more solid than
the Lord's foundation stone.

Seems solid enough.

But Hutton was claiming that this hard
stuff which seems so ancient and immutable

was actually the prime example of a young
rock which had once been almost liquid.

He was saying this was born molten.

To claim that granite
had started out molten

challenged the whole biblical
view of creation.

220 years ago, this was heresy.

Hutton needed to find
some evidence from the field.

At the age of 60, when he should have
been at home with his pipe and slippers,

Hutton hit the trail.

He headed north east from Edinburgh

into the wild hill country
of Blair Atholl in Perthshire.

Travelling in the 1780s was a wee
bit different to what it is today.

It's going to take me
a couple of hours

to go from Edinburgh to Blair Atholl
in the South East Highlands,

but for Hutton it would have
taken three days on horseback.

His search for stones would
routinely give him saddle sores.

He once wrote, "Lord pity the arse
that's clagged... " That's "attached" -

".. to the head
that hunts for stones. "

But despite a sore arse,
it didn't put him off.

'On the 16th of September 1785,

'Hutton travelled along
this track in Glen Tilt.

'Hamish Cruickshank is a
gamekeeper on the Atholl Estate. '

You got a hell of an office. It's one of the
best offices in the world. It's fantastic.

147,000 acres of office.

So if I was coming up here in 1785,

it wouldn't be much different,
I guess? Not much different.

You would be wearing the same sort
of equipment as I'm wearing now.

The tweeds - really only the
design has changed over the years.

Think you've more camouflaged
in the landscape than I am!

Certainly looks like it! Don't think I
could stalk up on some deer with this.

Hutton chose to explore Glen Tilt

because two of Scotland's
great rivers meet here.

The River Dee runs over
a bedrock of pink granite.

The River Tay has a bedrock
of grey sandstone.

Where the rivers met,

Hutton hoped the granite
and sandstone would also meet.

The contact, the meeting place,
is right down the river

and that's what Hutton
was going for.

And if he could find
where the two rocks met,

maybe he would find evidence

that granite had flowed as
a molten liquid into the sandstone.

As Hutton made
his way along the river,

he could see the grey sandstone
frustratingly close to,

but never quite touching,

the pink granite.

Then Hutton arrived at these rapids.

This is the bit.

Look at this!

Wonderful.

Hutton must have been
just so pleased to see this.

You can see there the grey rock,
that's the layered rock,

and then in front of us here, this
pinky rock, which is the granite.

And here, especially
over on the other side,

you can see it's all mixed in.
If you come and look,

actually there, look down there,

you see the pink rock and
the grey rock is all muddled in.

And that's the bridge.
There used to be a bridge over here.

Now there's no easy way
to get across.

Well, Hutton had saddle sores. I
think I'm going to have rope burns.

Woo-hoo!

This is the rock Hutton
was looking for.

There's a cracker over here.
Look at this.

This is the beautiful red granite

and this is the grey layered
rock, the sandstone.

You can see how the granite is injecting
itself forcefully into the sandstone.

This is a brilliant bit.
Look at this. It's just mad.

There's bits down here.
It's so irregular.

It's kind of like
Italian ice-cream or something.

Lovely. You know,

it's crystal clear here that
the granite came from molten rock.

It's getting injected in all
directions. It's this way, this way,

over there it's going up there,
it's across that way.

This is like a geological
battle zone.

These rocks showed that
the landscape had changed.

It had not, as the Bible said,
remained unchanged since creation.

Molten granite was proof of
a giant heat engine in action.

This discovery in Glen Tilt
was a great moment for Hutton.

It's the kind of thrill that
every geologist is after.

It's why I too am fascinated
by the rocks all around us.

The core to being a geologist is
this ability to read the landscape

but it's really hard to
explain to someone else.

You just get used to it.
It's kind of intuitive.

It's kind of like a curse as well
because suddenly you can't really...

I don't know, enjoy a landscape
without thinking,

"What is that? How was it
formed? Is that sandstone?"

I always get told off
when I'm on holiday

for working when I'm
looking at the landscape.

My wife says, "Stop geologising,
stop working!"

I say, "I'm just looking. "
But it's true.

I think a geologist
can't look at what's around

and not think,
"How was that formed?"

From his observations in Scotland,

James Hutton had proved much of his
theory of the earth as a system.

Rocks were molten and cooled.

They were eroded and built up again.

Hutton was not yet satisfied,

and he set off once more.

This time he was in search of clues

as to how long this planet cycle
of renewal had been going on for.

Was the earth thousands of
years old, as the Bible said,

or was it much, much older?

In 1788, Hutton headed to Siccar
Point on the Berwickshire coast,

just a few miles from his old farm.

This time in April, normally, the
seas round here can be treacherous,

but we've got
a beautiful calm sunny day,

which is pretty much the weather
Hutton had when he came here by boat

with two friends to try and convince
them about his theories of the earth.

What Hutton was on the lookout for

turned out to be the most celebrated
geological find in history.

Hutton knew this coast well.

What intrigued him was the different
angles of the rocks along the cliffs.

He had seen vertical layers
along part of the coast...

.. but he knew that further north,
the angle changed completely -

the layers were horizontal.

'Hutton's curiosity
made him take a closer look. '

Cheers.

It's so good to be here.

I mean, I guess...

I guess it looks like a pretty normal
piece of rocky foreshore to most people,

but this place is geological gold.

I mean, quite simply,

this is the most important
geological site on the planet.

You'd never know it to look at it, but
there's a huge story to be told here -

an epic tale of geological violence.

It takes you a while to see it,
to get your eye in,

but Hutton, Hutton
knew instantly what he'd seen.

Nothing less than the birth
and death of whole worlds.

What's remarkable is that
Hutton could see all of this

not in a giant cliff but
a five-foot-high section of rock.

In these horizontal
and vertical layers of rock,

he saw one long geological cycle
piled on top of another.

These layers of vertical grey rock
started off as slurries of sand and mud

sloped off an ancient landmass
and deposited in the ocean.

They built up on the sea bed
as horizontal sheets

inch by inch over millions of years.

But although they
started off horizontal,

all that was about to change,
because the ocean started to close.

What Hutton couldn't have known,
but we've since discovered,

is that continents move
slowly across the globe,

and this is why the rock layers
are vertical and don't lie flat.

Over millions of years,

a continent slowly and relentlessly
drifted towards Scotland.

The sea-bed crumpled,

pushing the layers
of bedrock upright,

higher and higher, until
they became hills and mountains.

And there, erosion started again,

rivers and rain
wearing down the land.

On top of the upright grey layers,

fresh sediment gradually built up and
solidified into new flat layers of rock.

Hutton didn't know exactly what
caused the formation at Siccar Point.

His brilliant insight was to realise
it must involve gradual processes

that happened not in
biblical time but in deep time,

stretching back immeasurably.

Hutton was right and we now know
how old these layers of rock are.

This grey rock
is around 425 million years old

and this red rock
is about 345 million years old.

The gap between the two
is 80 million years.

And that is ultimately Hutton's
most important legacy -

an appreciation of deep time...

.. the timeline of a planet.

Hutton had a phrase that he used, he said, "No
vestige of a beginning, no prospect of an end. "

In other words, a timelessness
in which small gradual changes

can achieve almost anything.

Here at Siccar Point, James Hutton
realised that if one ancient rock formation

could sit on top of another, this process must
have taken an inconceivable length of time.

He had no idea of how long.

Indeed, he never offered
an exact timescale.

He could only imagine the cycle
of the Earth had gone on endlessly.

Hutton's recognition of Deep Time
was an extraordinary breakthrough,

every bit as significant in its way

as Darwin's theory of evolution
or Einstein's theory of relativity.

As with all these great scientific advances
it was difficult for people to believe.

Ideas in geology... Well, in science
for that matter, are kind of like

a relay race where the baton
gets passed from hand to hand.

Hopefully each time the baton gets passed along,
the ideas get more solid and more accepted.

But in the case of Hutton,

that baton got seriously
dropped along the way.

60 years after Hutton's death,
Britain's most respected physicist

tried to calculate
the age of the Earth.

A Scottish scientist so successful he
could afford a luxury yacht like this.

Its time to introduce you to
a very different kind of scientist.

William Thomson - better known
as Baron Kelvin of Largs.

He was a colossus of world science.

He's best known for
the temperature scale.

"Degrees Kelvin," - that's him.

He was everything
that Hutton wasn't.

He was deeply embedded in
the academic establishment.

He was forceful, articulate,
a real showman.

Kelvin was a brilliant scientist
supremely confident in his own ability.

He rejected Hutton's theory of the
Earth as a system of endless change.

The Earth had to have an age, even if
it was far older than the Bible said.

Kelvin thought that Hutton and
his followers were unscientific.

His main problem was the claim
that the Earth showed

"no vestige of a beginning,
no prospect of an end,"

and that it was in
a kind of perpetual motion.

In other words he thought that geologists
were trying to break the laws of physics.

It was time to smash
that idea to pieces.

Kelvin was a showman.

And he had a dramatic way to show that the
Earth must be losing energy all the time.

That could have been my head.

Here we have our
15 kilogram cannonball.

15 kilos I can hardly hold it.
It's a lot heavier than it looks.

All right, so what do we do?
So I want you to stand in position

and we'll bring the cannonball up.

'Dr Stuart Reid
from Glasgow University

'shows me why Kelvin was convinced
that Hutton's theory

'of endless change
in the Earth was wrong. '

Just hold it with your hands.
'This canon ball is a pendulum. '

So heavy it's pulling me forward,
it's such a weight.

Bring it right up to your nose.
Right here we go.

'When I let the pendulum go,
it'll swing back towards me.

'If it hits me, my head will
end up like the melon. '

OK, here we go.

Why exactly is this not
braining me then?

It's not possible for the cannonball
to end up swinging higher

than where you let go of it,
because it can't gain energy

from nowhere and in actual fact it's
losing energy because of friction

in the rope cos of the air resistance
as it's moving back and forth

So the amplitude is decreasing as
it's swinging and you can see that.

'For Kelvin this demonstrated that
the planet, just like the pendulum,

'must lose energy all the time.
The Earth could not be

'in a cycle of change that would
never slow and never stop. '

You know it's a simple but effective
demonstration of the real problem

that Kelvin had with Hutton's theory the perverse
notion that the Earth was constantly creating

destroying then recreating its
surface over and over again forever.

In fact the Earth should be
constantly losing energy,

just like this pendulum will
eventually come to a halt...

eventually.

Based on the principle that
everything has to start and stop,

Kelvin was sure that the Earth
had a beginning - an age.

Hutton was a bit, well, woolly, he
never gave a precise age for the Earth.

Kelvin wasn't going to let him
get away with that.

Grand claims needed to be
backed up by hard figures

and he, Lord Kelvin,
was the man to get them.

He was going to take on the most audacious
and controversial question of the era.

Lord Kelvin was going to calculate
the age of Planet Earth.

This is a lump of granite...

and we're gonna try and melt it.

Now, granite melts about
1,200 degrees Celsius

several tens of kilometres
buried beneath our feet.

We're going to try and melt it here
with a blow torch.

Take it away.

Meanwhile I'm going to film it
with a thermal infrared camera which

is going to try and capture the heat
and already I can see it soaring up.

It's 280, 300 degrees Celsius.

Whoa, it's bright, that's for sure!

Kelvin believed
the Earth started off molten.

Now it's hard to look at.
That's 1,000.

We're at 1,000 degrees Celsius.

The melting point of rock was Kelvin's start
point to calculate the age of the Earth.

He took this as the temperature
of the planet when it was created.

And there it is -
1,200 degrees Celsius!

HE CHUCKLES
Oh, yeah, look at that!

This is molten rock!

Beautiful!

Kelvin argued that the planet
couldn't stay molten forever.

Can we stop a second?

This is now just basic physics.

Once something's heated up it can't
stay hot - it has to cool down.

From his experiments Kelvin knew how
long it took small objects to cool down.

If he scaled up his figures
to calculate how long it would take

an object the size of
the planet to cool down,

then he would have
the exact age of the Earth.

For years, Kelvin continued to
tweak and refine his calculations.

He finally put the age of the Earth
at between 20 and 40 million years.

Although we now know
the calculations aren't accurate,

Lord Kelvin's figures
had an enormous impact.

He provoked intense debate
about the age of the Earth

and upset nearly everyone.

This is Kelvin.

Most times I've seen this statue,
he's had a traffic cone on his head.

And he was ridiculed too when he
published his age of the Earth.

The Church hated it because
it made the Earth too old.

Fellow scientists they hated it
because it made the Earth too young.

There just wasn't enough time for
Darwin's theory of evolution to happen.

And as for Hutton's heat engine,

well, on Kelvin's timescale,
that was a non-starter.

Lord Kelvin had made
a crucial error.

His calculation was based on the idea that the
Earth had cooled to a completely solid state.

But as we now know the Earth's
interior didn't just cool

like a lump of molten rock.
Parts of it stay molten,

just as Hutton imagined
but couldn't prove.

Kelvin might have been wrong but his age
of the Earth stood for almost 50 years.

Right up until 1898 when the rocks
themselves revealed the truth.

A few years before Kelvin died,
there was a major breakthrough.

Scientists discovered a source
of energy deep within the planet

that has helped keep the
Earth molten far longer

than Kelvin could have imagined.

Radioactivity.

MACHINE BEEPS

This is a pretty ordinary lump of
granite from the Scottish Highlands.

MACHINE CRACKLES

And those clicks you're hearing
are particles that are hitting

the thin sheet at the front
of this Geiger counter.

They're coming from a tiny amount of
radioactive uranium contained in the rock.

MACHINE CRACKLES

We tend to think of
radioactivity as man-made

but it's actually
a natural phenomenon.

A powerful energy source that's been
around since the birth of the Solar System.

Radioactivity is one of the key forces
that makes Hutton's theory correct.

I'd love to meet Hutton and, over
a whisky and beside a warm fire,

tell him about all the things we've
discovered since he's been gone.

Top of that list
would be radioactivity.

The energy of radioactivity
and the heat that it generated

has kept parts of the planet's
interior molten.

It's part of Hutton's heat engine
which has allowed the Earth's surface

to be constantly recycled
and rejuvenated.

But there's another reason why I'd
love to tell him about radioactivity,

and that's because as well as
explaining his heat engine,

it's been responsible for telling
us just how old the planet is.

We can now look at the most ancient rocks
on our planet and discover their true age.

I've returned to Torridon,
in the North West Highlands.

I'm hoping to find the oldest
rocks in Britain up here.

I want to find out
just how old Scotland is.

And radioactivity
will give me the answer.

I'm heading into the back country with
fellow geologists John Wheeler and Ian Miller.

You can see it's kind of swirly,
can't you? Oh, yeah.

'This hill is 50 times older
than the era of the dinosaurs.

'It is one of the earliest
parts of our planet. '

Wow, this is spectacular, isn't it?

Look at this!

This whole outcrop is just... kind
of vein after vein after vein

of this beautiful white rock.

This rock is called
Lewissian Gneiss.

This is kind of rock heaven for me.

It's just the textures,
the shapes the colours

of this Lewisian Gneiss -
it's beautiful, gorgeous.

And here this stuff's coming
across and it stops.

But what's even more fascinating, more
mind-blowing than how gorgeous it is,

is that this rock could be part of
the very first bedrock of Britain.

Here we go.

This is the dark side of geology.
It's cold, hard work.

Yes!

'Much as I love this rock, we need to
take a sample so we can measure its age. '

OK, that's pretty good. Is it?

It's getting nasty now the snow's really coming
in but we've got it. We've got the rock we wanted.

It's a beautiful piece
of Lewissian Gneiss.

And apart from just looking
gorgeous, this is the question -

am I holding in my hand a fragment

of one of the oldest bits
of Britain?

We're going to find out but
we've got to get it to the lab.

Let's get off this mountain.

So this is it, this is my rock.

Here it is.

The plan now is to find out how
old this piece of Scotland is.

The key thing
that we have to do first off,

is we have to smash the hell
out of this rock and we do this

in this machine here.

LOUD CLATTERING

'The ground-up rock contains
the radioactive crystals I need. '

Ha! Look at it.

So that's what our rock started like
and that's what it is now.

Somewhere in here are
the little crystals we want today.

'Now we're going to examine those crucial
crystals using an electron microscope. '

That creates a vacuum?
That's creating a vacuum inside.

From your sample that you collected,
we've managed to extract

a large number of zircon crystals.

'The zircon crystals
are time capsules.

'They're full of radioactive
uranium, which breaks down into lead

'at a regular rate. '

You can actually see the shape
of the crystals quite nicely.

Absolutely, yeah.
That's really beautiful.

'The proportion of uranium and lead left in
the zircons will reveal the age of the rock. '

'The machine spits out an
extraordinary bunch of numbers. '

Lots of numbers. Lots and lots of
numbers. My gosh, lots of numbers.

Many many numbers.
They're ranging from about 2,500,

up to a little bit over
300 million years old.

These ages are just unfeasibly old.

I mean, 3,129 million years. It is
astonishingly old. It's amazing.

You know the fact that it's between
2.6 and three billion years old

is truly remarkable.

I mean this thing has been around for
two-thirds of the age of the planet.

The Earth is 4.6 billion years old.

And the notion that a lump of Scotland
is almost 3,000 million years old?

Well, what would Hutton
have made of that?

The rocks of Torridon were created

when the very first continents
on Earth were being born.

The ancient landscape of Scotland is a witness
to billions of years of geological change.

It was one pioneer who made this
vision of our landscape possible.

James Hutton made one of the
greatest leaps in human thought.

When he looked at the landscape he
saw what no-one else had seen before.

He was the first to grasp the true,
vast age of the Earth.

And it was that discovery more
than any other that's allowed us

to piece together the complex story
of the life of our planet.

'Next time: I'll follow in the
footsteps of the gung-ho geologist

'who uncovered Scotland's
volcanic past.

'And the unsung hero... '

You can actually see it
starting to go up there.

'.. who solved the mystery of what makes
continents move across the surface of the globe. '

Subtitles by Red Bee Media Ltd

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