Narrator: Jules Verne
thrilled the world
with tales of fantastic journeys
to the bottom of the ocean,
the North and South poles,
and the Moon.
Back in the 1 9th century,
none of his adventures
was thought possible.
Since then we have realized
them all, except one.
ls science and technology
finally ready to fulfill
Verne's ultimate dream?
Can we journey
to the center of the Earth?
[ bell tolls ]
Amiens, a small town
near Paris, France,
was home to one of the most
visionary authors of all time.
He's known as the father
of science fiction.
Some say he invented the future.
He was Jules Verne.
adventure and science fantasy,
much of which
has become science fact.
His heroes flew to the Moon
first real attempt
and circumnavigated
the globe in days
at a time when it took months.
Like all Verne's best sellers,
''Journey to the Center
of the Earth''
was a product of
rich imagination and research.
How much did his scientific
crystal ball get right?
When Verne
was writing ''Journey,''
little was known about
the interior of our planet.
The earth sciences
were in their infancy,
but the 1 9th century
was a time of great discovery.
''Journey'' is set in 1 864.
Verne's heroes are German
professor Otto Lidenbrock,
his nephew Axel, and
their lcelandic guide, Hans.
Their quest takes them
to the center of the Earth
and back through time.
Verne's prehistoric monsters
were the real thing.
The underground ocean,
he invented.
[ thunder crashes ]
Science and technology,
thrills and spills.
No other writer captures
so well the excitement
of exploration and discovery.
How much did he get right?
Since Verne's time,
we've conquered space,
but if we are ever to journey
to the center of the Earth,
we still have a long way to go.
Who hasn't, as a child,
daydreamed
about digging through the Earth
and popping up
on the other side of the world?
lf we could do this,
where would we end up?
Jumping into a hole in Spain
would bring you out
in New Zealand.
Argentina would link to China.
And from Miami, you could
drop in on Perth, Australia.
lf these dream
tunnels were real,
you could just jump in
and let gravity take over.
Gravity would cause you to
accelerate towards the center,
and then slow you down again,
allowing you to step out
on the other side...
lf we could dig a hole like
this, what would we find?
At the Earth's center
is a massive ball of iron
known as the core.
An outer core of molten
iron swirls around it.
Next is the mantle, slow-moving
hot rock 1 ,800 miles thick.
ln contrast, the crust --
the part we live on -- is thin.
ln fact, it's broken
into pieces called plates.
The crust's plates
are always on the move.
A journey down an eroded canyon
is like a journey back in time,
because it shows how the
Earth's crust has changed
and continues to change.
Layer upon layer of rock
has built up on the
surface of the Earth
over millions of years
and is relentlessly worn
away by wind and water.
But the deepest canyon on Earth
is only two miles deep.
lt's 4,000 miles
to the center of the Earth,
but how far is that?
This airplane is flying
at 1 2,000 feet.
The parachutists
will fall 7,000 feet
before opening their chutes.
They free-fall
at over 1 00 miles an hour.
At this speed, they'd reach
the Earth in just over a minute.
lf they could continue like this
to the center of the Earth,
it would take over 36 hours.
lt's as far
as Chicago to London.
Caves were
an obvious starting point
for a journey to the
center of the Earth.
The deepest cave Verne knew of
was at Vichada, Colombia.
lt had been explored
to 2,500 feet.
Not one for half measures,
Verne wondered what would happen
if his explorers
went much deeper.
Jules Verne reveled in
technological invention
and outfitted his heroes
with electric lights
powered by chemicals.
He knew naked flames
were a hazard underground
and came up
with this original solution
at a time when gaslight
was still a luxury
and electricity known
only to scientists.
The geologists of the day
thought that erupting volcanoes
must leave giant
tunnels underground.
Verne was fascinated by geology
and led his explorers
past rich seams of minerals
and precious metals...
...and into cathedrals
of stalactites
and stalagmites built of lime
by a billion water drops.
Caves had been
tourist attractions
since the beginning
of the 1 800s.
Verne used these as a route
to the Earth's center,
but not caves like this.
Modern caving
began in the 1 880s,
directly inspired by ''Journey.''
Pioneering cavers
didn't have the high-tech gear
we take for granted.
Wet suits were unknown.
lnstead of lightweight alloys,
their tools were made
of steel by blacksmiths.
Narrator: Caves had been
tourist attractions
not waterproof man-made fibers,
and had to hire porters to carry
all the heavy equipment.
Today caving
is more popular than ever.
Even so, it's thought
are yet to be discovered.
These are the new frontiers in
the exploration of our planet.
But these days we know we can't
get to the center of the Earth
this way.
The deepest caves
go down only 5,000 feet.
But need,
and some would say greed,
have driven us to penetrate
much further into our planet.
Early mining started
as simple holes in the ground,
but as the surface deposits
have been used up,
we've had to go deeper,
digging shafts and tunnels.
And if the prize is big enough,
it's worth going
a long way down.
These men are plummeting
towards the center of the Earth.
They are in search of gold,
a metal valuable enough to dig
two miles down to get it out.
The mine is so deep
that the cable would break
under its own weight
if it was continuous.
That's why the miners have
to change cages halfway.
They're already 2,000 feet
below the bottom
of the deepest mines
Verne knew about.
Today this is
the deepest mine on Earth.
lt's also the deepest anyone
has been into the Earth's crust,
and these miners do it
every day going to work.
They're 1 2,000 feet down.
There's a way of
going still deeper
that doesn't involve digging,
but it does require diving.
The deepest place on Earth
is at the bottom of the ocean.
ln 1 960, a submersible
called Trieste got there,
a century behind Nautilus,
the submarine in Verne's book
''20,000 Leagues Under the Sea. ''
Apart from Nautilus' crew,
the two men aboard the Trieste
are the only people to penetrate
this far into the abyss.
More men have
walked on the Moon.
Here the ocean is deeper
than our highest mountains.
The Trieste dived as far
from its surface
as the airliners cruising
overhead --
We can get deeper
than that by drilling.
This is the site of the bid to
drill the deepest hole on Earth.
ln Verne's day,
drilling for water
was routine
down to around 1 00 feet.
But five years before ''Journey,''
drills were used to find oil.
The technology
went into overdrive,
but even a century later,
the Russian goal of 40,000 feet
looked like a step too far.
A German attempt
had failed at 30,000 feet
because the rock was so hot
and soft, it sealed the hole.
After 1 4 years,
the Russians made it.
Core samples were eagerly
analyzed by geologists.
No one had ever seen rocks
from this far down.
So, how near have we got
to the center of the Earth?
Cavers venture 5,000 feet down,
while miners work
at 1 2,000 feet.
And the Trieste
plunged to 34,000.
Up to now,
we've drilled to 40,000.
But it's 21 million feet
to the center of the Earth.
We've barely
scratched the surface.
Why does this man
keep scrambling
and squeezing his way down?
He's in search of something
more precious than gold.
Narrator: Jules Verne lived
at a boom time for science,
when the natural world
took center stage.
He trained as a lawyer,
not a scientist,
but started to devour
scientific papers as a student,
and kept up with new
discoveries all his life.
Always hungry for material,
Verne picked the brains
of many top scientists.
Charles St. Clair David,
a world expert on volcanoes,
provided inspiration
for ''Journey.''
ln the middle
of the 1 9th century,
the big questions about the
Earth were still to be answered.
How old was it?
How was it made?
For many people, the answers
were a matter of faith.
The problem was science was
suggesting that may not be true.
Darwin had just published
his theory of evolution.
The world and all living things
weren't made in 6,000 years,
but millions.
Knowing about fossils
had prepared Verne for that,
but fossils embarrassed
the faithful.
How could their god let
his creations go extinct?
When mammoth fossils
were found in America,
even Thomas Jefferson believed
they must still be alive there.
lt was just too good an
opportunity for Verne to miss.
ln his novel,
Verne conjured up a scene
in which the professor,
Axel, and Hans
would find more than old bones.
What if they found, hundreds
of miles below the surface,
ancient species living on?
We're still finding fossils
all over the world.
We have better tools
than the hammers and chisels
Verne would have recognized,
but freeing the precious
bones from the rock
is still a painstaking task
requiring skill and patience.
Benton : Fossils are the remains
of plants and animals
that once lived.
So, for example, if you have a
creature that lives in the sea,
when it dies, its carcass
would fall to the bottom.
And over time, the bones
would be picked clear of flesh
by any scavengers down there,
and then it would
eventually be buried,
presumably by sand or silt.
Then in the course of maybe
tens or hundreds of years,
with pressure of
more sediment on top,
the bone is infiltrated
with minerals.
And there you have a fossil.
Narrator: ln Verne's day,
enthusiasm often got
the better of expertise.
Bones of different species
might be assembled
to make animals
that never walked the Earth.
Things are very different today.
Benton : So the
paleontologist is a detective
who looks at these
bits and pieces
of ancient plants and animals,
puts them together using
anatomical knowledge,
comparisons with
modern forms,
and you can literally
bring the past back to life.
Narrator: This may be the oldest
plant-eating dinosaur yet found.
lt lived on tropical islands
like those in the Caribbean.
So why, Verne would have asked,
was this one found in Britain,
where it's cold and damp?
Because 200 million years ago,
Britain was way down south
near where North
Africa is today.
And the sea level
was so much higher,
the hills of Britain
were islands.
By Jules Verne's time,
people understood a little bit
about the history of the Earth.
Geologists had been studying
the sequence of rocks
for about 30 years or so.
And they realized
as you go back in time,
you got into more and
more ancient rocks.
And as you looked
at the fossils,
you got more and more unusual
and ancient-looking creatures.
Narrator: ln his book,
Verne was able to bring
the past back to life
and adapt species of the
present to life underground.
He knew that plants
couldn't survive there
since they need sunlight, but
figured that fungi could thrive.
ln the higher temperature
and humidity deep down,
he had his heroes
encounter mushrooms
of awesome proportions.
But what can really be found
on a journey to the
center of the Earth?
Bats may be the
best-known cave dwellers,
but they only use
caves as hotels,
going out at night to feed.
You have to go deeper
to find a stranger life.
Apart from the oceans,
no other habitat is so alien
to our experience.
Most of the animals that live
here came from the surface,
perhaps fleeing changes
in landscape or climate.
Over thousands of years, they
have adapted to this dark world.
They need no coloration
to protect them from the sun
and no eyes to see, since they
live in total darkness,
finding their food
by touch and smell.
Cave-dwelling animals,
known as troglodytes,
are difficult to study.
They live in such tiny crevices,
they may never be found --
even by the most
intrepid explorers.
But it's other
creatures down here
that are exciting
scientists today --
creatures so small, you can't
see them with the naked eye.
And to work with
these elusive life-forms,
John Parkes faces a commute
that most people would do
anything to avoid.
We do find life in the Earth
despite the fact
that the deeper you go,
the higher the pressures
and the higher the temperature.
But life is very small.
lt's microscopic organisms --
mainly bacteria --
and these organisms can
survive those conditions.
ln fact, some can grow
at temperatures
as high as 1 1 3 degrees
centigrade --
much higher temperatures
than boiling water.
The startling thing
about life in the subsurface
is the first estimates of the
total bacterial population there
indicate that
they represent about 7 0%
of all bacteria on Earth.
So the majority of bacteria
actually reside
in the subsurface.
They are not in this thin veneer
very close to plants and
animals we're used to.
Narrator: But what do bacteria
find to eat down there?
New discoveries suggest
it may be the Earth itself.
ln Verne's day, science
believed that all caves
were created by water
wearing away the rock.
But is this right?
These caves were formed
millions of years ago
before the sea level rose.
Now they are only open
to intrepid diver-scientists
like Sam Smith.
She believes it's not water
that eats away the rock --
it's bacteria.
l think that without bacteria,
caves and limestones
would not exist.
You really do need the bacteria
to form carbonic acids,
or other acids in the soil zone
above where the caves
might start to form or develop,
which then starts
to carve out the cave.
There's no doubt that over time
water corrosion
also plays a role,
but bacteria needs
to be there as well.
Narrator:
Microbes or meteors?
Join our teams of scientists
as we go deeper still,
searching for clues
about what formed the Earth.
Narrator: Sam's study site is in
the Yucatan Peninsula in Mexico.
The caves extend for 50 miles
and are up to 400 feet deep.
lf Sam is right,
rock-eating bacteria
hollowed them out,
and they're still at it.
The quest for the bacteria
takes her deep
into the underwater maze.
This is a dangerous place.
Sam's exploration is at
the limit of diving technology.
There are only three scientists
in the world experienced enough
to dive into caves this deep.
All their equipment
has a backup, or even two,
since problems
must be solved on the spot.
This is no place to get lost
with your air running out.
When Sam finally gets to a spot
where the rock-eating
bacteria could be at work,
she makes sure the samples
she collects will be perfect.
Smith : To take our samples,
we used 1 0-meter-length tubing,
silicon tubing.
That basically allows us
to take a sample
at a point 1 0 meters
upstream of us,
and it minimizes the diver's
disturbance to the water
so that samples are sterile
and as clean as possible.
Narrator:
Having come this far,
it's vital that Sam
doesn't contaminate the samples
with her own bacteria.
Only then can
the return journey begin.
Smith : After we've
collected the samples,
we immediately take them
back to the cave surface
where they are
put on ice right away
and kept on ice until we get
them back to the field lab.
Narrator: The bugs are cooled
to 40 degrees
and flown in this standby state
from Mexico
to Sam's lab in England.
lt takes about eight hours.
A Jules Verne hero
managed to race
around the world in 80 days.
lt was 1 0 years
after Verne wrote ''Journey''
that Louis Pasteur
put bacteria on the map.
And for another century,
the world would see
bacteria as a nuisance.
Now scientists like Sam
suspect they may become a vital
and inexhaustible commodity.
First she wants to know how many
rock-eating bacteria there are.
She wants to know
if they're all the same type.
Most of all, she wants to verify
that the acids they produce
can carve out caves.
lf Sam's right about
these microscopic miners,
it's a giant step
forward for geology.
Smith : lt's something
that's quite exciting,
to think that
something so small --
so the bacteria which are
about a micron in size,
or one millionth of a meter,
can actually alter
something so large
and have such a large impact
on the environment around them.
Bacteria exist everywhere -- in
the air, in water, land, sea --
and anywhere we have
looked for them so far,
we've been successful
at finding them.
Narrator:
So, will we find bacteria
at the center of the Earth?
lf you wanted to think
about how deep we could go
and still find bacteria,
it probably
is temperature-dependent,
but we haven't reached
that maximum yet.
We haven't looked
deep enough yet
where they haven't been there.
Narrator: Because they can eat
what we can't eat
and thrive in conditions
we find extreme,
bacteria may turn out to be the
Earth's real buried treasure.
They're already at work
in our homes.
We all are used to using
biological detergents
in washing powders.
These come from organisms
that can grow
at 60 degrees centigrade.
lf we can get organisms growing
at 1 30, 1 50 degrees centigrade,
basically they could
make superb catalysts
for a whole range
of different compounds.
Narrator:
Unlike some other resources,
there's no shortage of bacteria.
This core sample of rock comes
from 200 feet below the surface.
lt contains as many bacteria as
there are people on this planet.
We've come up with bacteria
wherever we've drilled,
and however deep.
They can survive
for millions of years,
buried alive
without food or o xygen.
Some see them as an infinite,
untapped labor force.
The first oil wells
came on-line in Verne's time,
but the era of easy-to-get-at
fossil fuels is almost at an end
unless these new microbial
workers can help us out.
We know that we leave something
like 40% of all the oil
in reservoirs in the ground.
We can't extract it.
For example, if we were able to
manipulate these deep organisms,
they might be able
to convert the oil into gas,
and then several years later,
we could come back
and we've got a viable gas field
instead of a spent oil field.
Narrator: Verne's adventurers
didn't strike oil,
but they did find
platinum and gold.
They decided these were
too deep ever to be mined.
Verne meant by men.
He hadn't reckoned
on microbial miners.
The idea of using microbes
to extract minerals
was beyond even
Jules Verne's imagination,
but because some types
of bacteria digest rock,
they're already being used
to separate metals from ore.
And that's just the beginning.
One day, we'll be able
to put bacteria to work
at depths we just
can't tolerate.
Until then, we'll go on
doing it the hard way.
Mining at 1 2,000 feet
is difficult, dangerous,
and expensive.
Every mile you descend, the
Earth gets hotter by 50 degrees.
Here, a single bacterium
can live for 1 ,000 years
on a diet of nothing but rocks.
Bacteria living here
are natural alchemists.
They play an integral role
in creating deposits of gold.
As they break down the
rock and mineral ores,
the bacteria attract molecules
of gold to their outer skin.
Over millions of years,
the gold builds up to form
a glittering gold deposit.
The mine uses more electricity
than a small city,
making 80,000 tons of ice a day
and lifting ten tons
of ore two miles
to extract each
and every ounce of gold.
lt's the rock's history that
lets us mine here this deep.
Most places
would be simply too hot.
But in South Africa,
the Earth's crust is older
than in most other places,
so it's had more time to cool.
the gold accumulated
on the surface in a lake.
Over time, the land and the gold
was tilted and forced
down into the Earth.
No richer deposit
has been discovered.
Three-quarters of the world's
gold has come from it,
but that's only 2,000 tons.
To find out why metals like gold
and platinum are so rare,
we must go back to a time
when the whole of
the Earth was molten.
a continual rain of meteorites
pounded the molten Earth.
Each strike
brought with it more rock,
making our planet bigger
and scattering metals
over the surface.
Then a giant asteroid struck.
lts massive iron core
didn't stop on the surface.
lt sank towards the center,
and it attracted all the Earth's
metals to it as it went.
The asteroid's
lighter, rocky debris
went spinning around the Earth.
The fragments were drawn
together by gravity.
Within a year,
they formed our Moon.
That's why the Moon
has no metal at its core.
And it's why metal
is rare in the Earth's crust.
lt arrived much later
in meteorites from outer space.
lf we want much more metal,
we must go to the Earth's core.
lt's made mostly of iron
and nickel, but 1 % is gold.
That may not sound like much,
but the core is so vast
that its gold could cover all
the land on Earth knee-deep.
ln South Africa, the miners
are already going deeper
in search of more gold.
They plan to follow the
seam to three miles down,
where keeping the mine cool
could account for 20%
of the mine's outlay.
They may need
temperature-controlled suits
or robots to extract
the precious metal.
The Northern
and Southern lights --
beautiful and benign.
But what will happen
when the lights go out?
Narrator: ln 1 860,
no one really had a clue
what went on 4,000
miles below their feet.
Many people still believed
that the Earth was hollow --
a theory put forward
by the astronomer Halley,
of comet fame.
[ thunder crashes ]
ln 1 823 an American,
John Cleves Symmes,
had led an expedition to prove
that Halley was right.
He didn't succeed.
Jules Verne knew of Symmes'
theory and kept an open mind.
But he led his explorers into
an immense, underground cavern
in which they had
to cross an ocean
lit by lightning
and magnetic storms.
This was pure fantasy,
but the scene also drew on fact.
Verne's research
had convinced him
that traveling down
into the Earth
would be like
going back in time.
So the creatures stirring
in the deep were real...
Plesiosaur.
The first remains
of the long-necked reptile
were found in 1 820.
The dolphin-shaped ichthyosaur,
unearthed in 1 809.
[ roaring ]
Verne was right.
There is an ocean
at the center of the Earth...
a tempestuous sea
of molten iron.
As this surges in turmoil
around the solid inner core,
it generates magnetism.
A colossal force field
stretches into space,
protecting us
from solar radiation.
Sometimes we can see it.
The Northern and Southern
lights put on a show
when electrically charged
fragments from the sun
collide with the magnetic field.
But there's evidence
that its power is fading,
and that could mean we'll be
exposed to a lethal dose
of cosmic rays.
At Harvard, Jeremy Blo xham
is trying to find out
why this is happening.
Blo xham : One of the goals
of our research at the moment
is to try to develop a capacity
to forecast what's going
to happen to the magnetic field
in the future.
This is of particular
interest at the moment,
because over the last 1 50 years
we have seen the strength of the
field decrease by almost 1 0%.
And that's a rate of decrease
which is a characteristic
of the field
heading into
a magnetic reversal.
So an interesting question is,
will the magnetic field
actually reverse?
Narrator: A magnetic
reversal, or flip,
means the North pole becoming
the South and vice versa.
Compasses will point
the wrong way.
Navigation will be literally
turned upside-down.
But this won't be
the first time it's happened.
Blo xham : There's been
maybe 60 reversals
in the last 30 or 40
million years.
So in geological terms,
they're a very frequent event.
Just in the time scale
of human experience,
they're a very rare event.
Narrator:
But what will happen in a flip?
Will we be able
to find our way around?
Today magnetic compasses
are used less for navigation.
lnstead we use GPS satellites,
which won't be affected.
But before the flip,
the Earth's magnetic
shield will fail,
and without it, satellites
bombarded by radiation
will burn up in space.
lt's not only human navigation
that will go wrong.
Many animals rely
on internal magnetic compasses
for migration.
But no one knows
how they will manage.
But flips don't
happen overnight.
The force field fades slowly.
Jeremy Blo xham
is watching it closely.
Blo xham : There's a variety
of techniques
which we can use to see
how the field is changing.
We have modern measurements
from spacecraft
which are in orbit specifically
to measure the magnetic field.
We have permanent
magnetic observatories
set up at various locations
around the world
which continuously
make measurements
of the magnetic field.
But measurements like that
only tell us what's happening
on a time scale of decades
to perhaps a century
for the longest-running
observatories.
But the magnetic field
is changing on
a much longer time scale,
so we need to be able to ask how
can we find out how the field
has changed over centuries.
Narrator:
Fortunately, navigators
long depended
on the magnetic field,
and we've learned a lot
about its variations
from their charts.
And the changes continue.
Today, magnetic north
is leaving Canada
and heading
across the Arctic Ocean
at a steady ten miles a year.
But it's one thing to know
the poles are moving,
another to know why.
Blo xham : The Earth's
core is liquid iron,
or mostly liquid iron,
and the motions of that
electrically conducting iron
can create
what we call a dynamo.
But the details of that process,
how it actually works,
are still very
poorly understood.
Narrator:
To understand it better,
Dan Lathrop has built a working
model of the Earth's core.
We've been building
a sequence of experiments
progressively larger
and higher powers
to try to get
the same parameters
as occur in the
Earth's outer core,
and to try to
understand how the Earth
generates its magnetic field.
[ beeping ]
Keep an eye
on the temperature, too.
Right.
We like to know what sets --
how strong the Earth's
magnetic field is.
Also we would really like
to understand what causes
all of the changes
that are seen --
anomalies in the field
and reversals,
and to be able to both
understand what causes them
and to be able to predict them.
Narrator: The floor
of the Atlantic Ocean
bears witness to
flips of the past,
because lava lines up
with the magnetic field
as it solidifies.
The problem is flips
aren't regular.
To predict the next one,
we must know what's
going on in the core.
Okay, getting ready
to run at 1 0 RPS.
Ready to go.
Narrator: At the heart
of Dan Lathrop's dynamo
is a sphere
filled with hot sodium.
Electrically, sodium
behaves like molten iron,
but it's 1 ,000 degrees cooler.
A propeller creates
the sort of turbulence
thought to be caused
by the rotation of the Earth.
Up to now, they haven't
been able to generate
a steady amount of magnetism,
but they have learned
that small changes
in speed and temperature
significantly affect
the magnetic field.
Okay.
Lathrop:
ln the other experiment,
we have a geometry very close
to the Earth's outer core,
where we rapidly
rotate a sphere,
which has a layer
of liquid metal,
and then we heat the outer edge
and cool the inner sphere
and set up convection,
like you might have boiling
in a pot making pasta.
ln this case, it's sort of
the churning of the liquid metal
that gives rise
to a turbulent flow
that affects the magnetic field.
Narrator: The next step
is to build a bigger model.
After all, the real Earth's core
is over 4,000 miles in diameter.
Lathrop: There are really
three main questions
that we're trying to understand
in the experiments.
We'd like to know what sets
how strong the Earth's
magnetic field is.
We also would really like
to understand what causes them
and be able to predict them.
And the last thing is
we'd like to know
what are the limits
to having a dynamo in a planet?
So why does the Earth have
a dynamo and Venus does not?
Narrator: Einstein insisted
the question of how the Earth
generates so much magnetism
was the most important
unsolved puzzle of physics.
No one knows when
the next reversal will happen.
One thing is certain, though --
the magnetic poles will reverse.
Scientists in Verne's day
knew that magnetism
came from within the Earth,
but not about
magnetic reversals.
Yet he predicted
a magnetic flip.
His explorers
had been traveling for months.
Professor Lidenbrock reckoned
they were almost
at the center of the Earth.
They stopped to draw breath
and take a bearing.
That's when they realized
something was wrong.
Their compass had gone crazy.
Had Verne seen
into the future again?
He certainly knew
of the connection
between magnetism
and electricity,
because he tells us
that the compass flip
occurred during the storm at sea
when lightning struck the boat.
Don't try this at home.
Fortunately,
this isn't the only way
to find out when the
volcano is going to blow.
Volcanoes are
the richest source of rock
from deep inside the Earth.
The most active is in Hawaii.
This is the closest we can get
to what it's like
at the center of the Earth.
lt's a reminder
of the heat and power
hidden beneath
the surface of our planet.
Kilauea volcano
has been spewing out lava
for thousands of years
without a letup.
lt single-handedly
built the island.
Molten rock, called magma,
surges up from near
the Earth's core
and blazes through the crust.
The stream, known as a plume,
lets inner Earth let off steam.
lt's like a safety valve.
Elliott: We believe
that the volcanism in Hawaii
is ultimately caused by a
hot plume rising up beneath it,
which occurs because material
at the bottom of the mantle
is heated up by the core.
The core's maybe
and heating it up
causes it to become less dense,
and then it rises
through the mantle.
A good analogy
is with the lava lamp
that you might see
in someone's living room.
Narrator:
lt's lamps like this
that show us what's going on
in the Earth's mantle --
the layer between the
core and the crust.
Rock, heated by the core, rises,
while cooler material
sinks from the surface.
lt's this never-ending process,
known as convection,
that pushes magma
to the surface,
where it erupts as lava.
Elliott: Hawaii is a bit
of a special example.
lt's the most active
island volcano that there is.
lt erupts with
extreme frequency
and it's also
exceptionally runny,
and so the lava flows
tend to move very fast
and they have a high proportion
of these so-called
pahoehoe surfaces,
which are these beautiful,
smooth, ropy textures you see.
Narrator: Lava can build,
but it can also destroy.
lt can seldom be diverted,
and it wipes out anything
and anyone that gets in its way.
Early geologists assumed
that such torrents of molten
rock flowing out of volcanoes
must leave huge voids
and caverns behind them.
Jules Verne's explorers followed
one of these lava tubes
as they approached
the center of the Earth.
But the Earth had one last
surprise in store for them.
As the professor, Axel, and Hans
neared the center,
their path was blocked
by a rockfall.
There was no other route,
so they decided
to blast their way through.
Verne knew very well
that molten rock,
trapped deep in the Earth,
is under huge pressure.
lf that pressure is released,
it can start a volcano.
That's why blasting was a risk.
ln classic literary tradition,
the eruption they triggered
blasted our heroes
to the surface
without as much
as a singed eyelash.
Eruptions are how the
Earth recycles itself.
Convection currents
in the mantle
carry rock to volcanic vents
and fire it back to the surface.
Volcanologists today can't get
inside an active volcano,
but they get up close.
Tim Elliott plays his part
Elliott: As geochemists,
we tend to come in
after the thing's cooled down
and then knock bits off.
Narrator: Predicting eruptions
is every volcanologist's aim,
but it makes predicting
the weather look easy.
Lava samples tell us that the
Earth's composition is complex,
and it changes whenever a large
earthquake or eruption occurs.
For Tim Elliott,
who struggles to keep tabs on
this shifting underground world,
every sample is a rich
source of information.
For what will eventually be
a highly sophisticated
piece of analysis,
Tim starts by crushing the lava
in a machine Jules Verne might
well have designed himself.
The first thing is to break
the lava into pieces.
Then, it must be crushed
into a fine powder.
The next step must be
done with great care.
The hydrofluoric acid Tim
uses to dissolve the powder
is equally good at
dissolving skin and bone.
lt eats all the
rocky parts away,
leaving just the base elements.
Those are the parts
Tim's interested in.
[ beeps ]
The lava sample is heated,
and the acid evaporated
off overnight.
Once we've got a pure separate
of the element that we want,
we then take that
to the mass spectrometer
to analyze its isotope ratio.
Narrator:
Wherever they come from,
any two samples
of a chemical element
will be chemically identical.
But we now know
that they can differ physically.
A mass spectrometer
can tell them apart...
and tell Tim just where
in the Earth a sample came from.
This one came from
very deep, indeed.
So that maybe gives us a clue
that these things come
all the way
from the core-mantle boundary,
but in terms of the
ultimate depth of these things,
to some extent,
l hate to admit it,
we rely on the seismologists.
[ alarm blaring ]
Man :
Narrator: Seismologists can see
inside the Earth
without going there.
Their explosions create
shock waves of sound.
When the waves hit rock,
they bounce back
to sensors on the surface.
Since different rocks reflect
waves at different speeds,
seismology lets us map the
Earth's subsurface landscapes.
Can today's technology take us
to the center of the Earth?
lf so, what would we find there?
Narrator: Seismology
lets us see with sound,
and there's more to it
than creating big bangs,
as M.l.T.'s Rob Van
Der Hilst explains.
Seismology is pretty
much the only way
to get fairly direct probes
of the Earth interior.
There is a lot of development
in the seismic theory
and observational
seismology itself
to really give much
more refined images.
Narrator: Seismology is similar
to an ultrasound scan
that can show an unborn baby
in its mother's womb.
An image can be created
because sound travels
through different parts
of our body at different speeds.
Unlike this scanner,
which generates its own sound,
seismology can make use
of natural sounds
that occur
every minute or two...
...the sound of earthquakes.
Thankfully,
we don't notice most of them,
but there are actually
a million a year.
And they're shaking up our ideas
about what's going on
thousands of miles
beneath our feet.
Earthquakes are appallingly
destructive to human life,
but to scientists,
they have their uses.
The seismic waves
are like sonar.
By listening as they
pass through the Earth,
a picture can be built up
of a place no one can ever see.
First, the waves race
through the crust,
the skin on the
planet's surface.
ln some places,
only 4 miles separates us
from the intolerable heat
of the magma
in the interior of the Earth.
The temperature
is nearly 3,000 degrees --
so intense that the rocks
are partially melted.
in the core itself,
the temperature reaches
an unimaginable 7,000 degrees.
lt is the ultimate
nuclear reactor --
the engine driving the planet.
Van Der Hilst: What we can
really image very well
is the material that goes down.
ln some cases, we can see down
to the core-mantle boundary.
And all that information
tells us a little bit about
how density is concentrated
in the center of the Earth
and how density changes
with increasing depth.
Narrator:
Seismologists image rocks.
Petrologists make them,
mimicking the heat and
pressure of the deep Earth.
We know how deep they come from,
how deep they come from,
because the minerals
contain elements
like calcium and aluminum,
and the distribution
of these elements
between different minerals
depends on pressure.
So, by simulating
the pressure --
taking a sample like this and
subjecting it to high pressure
and seeing how the compositions
of the minerals change
as we change the pressure,
we can go back
and work out what depth
this particular
sample came from.
Narrator: The anvil
on which Bernie forges
his man-made minerals
is made of tungsten carbide,
a material so hard
we use it to make drills.
He puts a tiny sample of rock
in a ceramic tube,
a miniature furnace,
and then walls it up.
The bricks are specially shaped
to focus the force
he'll apply to them.
This way, he aims to reproduce
the massive pressures
to be found in the Earth.
Bernie: Over a period
of about four or five hours
we raised the force
to around 500 tons,
and we then apply a
current to the furnace,
which is in the
middle of that lot,
in order to raise
the temperature
to 1 ,7 00 degrees ''C.''
Narrator: The petrologist
awaits the outcome
as anxiously as a pizza chef.
lf the heat and
pressure are right,
the elements will fuse together
into an exact copy
of the mineral he's studying.
This tells him
where it came from --
in this case, 440 miles down,
where the pressure is a quarter
of a million times higher
than at the surface.
The advances in science
since Verne's time
have been breathtaking,
and we're still discovering
how the Earth was made
and how it continues to change.
We've come a long way --
not in distance,
but in knowledge.
We've ventured 200,000
miles into space,
but, as yet, we've only been
With all the knowledge
and technology we have today,
surely we can tunnel
to the center of the Earth.
lf we could tunnel to the core,
the rewards would be huge.
We could shut down
our power stations.
The energy we'd tap into
would never run out.
lt would be free
and cause no emissions.
We could dispose
of dangerous waste
in the world's
hottest incinerator.
Huge quantities of
minerals are there...
just waiting
to be brought to the surface.
Maybe we could build a
high-speed transportation system
through the Earth --
a global subway.
But it's not that easy.
This tunnel,
linking England and France,
took 5 years to construct,
and it's only 30 miles long.
lt's 4,000 miles
to the center of the Earth.
And would we actually
want to go there?
lt's an adventure that Dan
Lathrop would welcome.
Well, it's an interesting idea
for an adventure, l guess.
l'm ready to go
if it becomes possible.
Narrator: Meet the team that's
designing the first vehicle
capable of penetrating
to the center of the Earth.
Narrator:
Today's tunneling machines
have brains as well as brawn.
They drill and support
the tunnel as they go
and never stop.
But what chance has even
a smart monster like this
of getting to the
center of the Earth?
Brian Clarke has built tunnels
all over the world.
lf we're tunneling
to the center of the Earth,
there are different
combinations of material,
but, generally, we would start
in soft-ground tunneling.
We would move through into rock
and as we go to extreme depth,
the rock would change
in character
due to the temperature effect.
We almost certainly
would need to use
an arm with a cutter head,
tungsten carbide teeth on it,
to grind and smash the rock.
Narrator: Today's most advanced
mechanical moles
can dig 2 feet every hour.
At that rate,
tunneling 24 hours a day,
it would take 1 ,000 years
to reach the center.
We'd have to make them
work faster -- much faster.
Clarke: And if you think
of the tunneling machine
as a very large beer can,
and it's traveling end on end
down through the Earth
with cutters up front,
the closed face --
it means that the cutters,
cutting away at the soft ground,
are separated by a wall
from the men on the inside,
and all of the spoil, all of
the earth that's being cut,
is carried to the
surface in pipes.
Narrator: The amount of rock and
spoil coming out of the tunnel
is almost unimaginable.
We'd need to extract four giant
truckloads of earth per hour --
And that's if we tunneled
straight down, not on a grade.
We'd have to design
a new type of vehicle
to transport us
through the tunnel --
maybe a capsule
able to withstand the extremes
found deep inside the Earth.
The deeper we go,
for every kilometer in depth,
we're picking up a 30-degree
centigrade temperature rise,
and that is causing us problems.
The rock is getting softer.
lt's getting ductile as a result
of the higher temperatures.
We're having to resist
those temperatures
so that people can work
within the tunneling machine,
or we would need to produce
a remote machine.
l think we're now
stretching credibility.
Narrator:
But it's not only temperature
that will be a problem.
There's also massive
pressure down there.
l would say it would be
incredibly difficult.
l think, in comparison,
the environment,
as you go deeper
into the center of the Earth,
is much more harsh
than what you would find,
for the most part,
for space travel --
with the temperatures
and the pressures you'd find.
Lathrop: lt's actually
a much more hostile environment
than going in space
or down in the ocean.
And in particular,
high pressures are such
that we wouldn't know
how to make a vessel
that you could go inside
and not get crushed down.
Down, really, past a few miles,
the pressures will be --
start to get too high for any
sort of normal technology.
Man on radio: We have
ignition sequence start.
Narrator:
We already know a thing or two
about building complex vehicles.
Could we spin off
space technology
to help get us
to the center of the Earth?
Sedwick: One of the biggest
issues you're gonna have
is gonna be the extreme
temperatures and pressures.
Some of the best materials
that we have, currently,
for dealing with
temperatures like that
would be the ceramic tiles
on the shuttle
or some kind of carbon carbon
or any type of
carbon-based material.
Narrator:
But here's the hitch --
while man-made materials,
like ceramics and carbons,
withstand heat,
they lack strength.
Metal is strong, but most steel
melts at around 2,500 degrees.
The temperature at the
Earth's core is probably 1 4,000.
We need new materials to build
our capsule or to shield it.
Sometimes,
if time is on your side,
and you're not gonna be exposed
to the temperatures for long,
simply having a material
with enough heat capacity
to absorb the heat
without melting
would be sufficient.
The best bet that l know of as
far as temperature is diamond,
and even diamond, l think,
has a melting temperature
of 3,200 Kelvin.
So from a materials standpoint,
l don't know of any
materials on their own
that would be able to withstand
those temperatures.
Narrator: As well as being
the ultimate adornment,
diamond is the hardest
substance known.
We can manufacture diamonds,
but could we make one big enough
from which to build a capsule?
Well, the diamond certainly
would be the strongest material,
and would allow you to have
the highest pressures.
lt's not entirely clear
you, of course,
can fabricate an entire
vessel out of diamond.
That certainly would be
an interesting thing,
and useful, in itself,
if someone could work it out.
Narrator:
For the capsule to survive,
it would have to be
continuously cooled.
Sedwick: The most difficult
thing to overcome
is being able to get the heat
away from the craft.
So the only way to be able to
stay in temperatures like that,
and to be able
to extract the heat --
maybe someday, with some type
of carbon nanotube technology,
you could have
a very long tether
that would follow the craft
down to the center.
And you could pump
some kind of coolant
that would go down
for thousands of kilometers
and draw the heat back that way.
But without some type
of active cooling,
l can't see how you would do it.
Narrator: The biggest problem
is the length of time
the capsule would be exposed
to the extreme heat.
lt would be like
trying to build a ship
to go in and skirt the sun.
lt would be that sort
of nasty high temperatures.
Narrator:
Since the center of the Earth
is as hot
as the surface of the sun,
we couldn't begin
to survive there.
Space has enormous challenges,
but most of it isn't hot.
lt's a vacuum,
so there's no air,
but you can
take or make your own.
And in a vacuum,
spacecraft and space suits
don't have to resist
colossal pressure.
Exploring space is no picnic,
but it's a cakewalk compared
to exploring the inner Earth.
Every 200 years, this city
is devastated by earthquakes.
The next one is overdue.
Can our Earth capsule save the
Narrator: A tunneling machine
using conventional technology
would be destroyed
by heat and pressure
long before it reached
the Earth's center.
Only 20 miles into its
it would melt.
But if, one day,
we could conquer
these technical problems,
there may be a way
we could send a capsule
deep into the planet.
We'd have to harness the
most powerful force on Earth --
continental drift.
The theory of continental drift,
also called plate tectonics,
was finally accepted by
science in the 1 960s --
a century
after Jules Verne's day.
lt said that the land masses
we're familiar with
started out as one
supercontinent.
This sat on plates that
migrated across the globe...
but the plates haven't stopped.
ln another 20 million years,
our world
will look very different.
This is the San Andreas fault.
These two plates
are sliding past each other
at the same speed
your fingernails grow.
Most of the time,
these plates slide smoothly.
But occasionally,
they get stuck.
And this causes earthquakes.
Plates don't always
slide past each other.
ln some places, one plate
is forced beneath the other.
That's what's happening
underneath Japan.
lt looks serene,
but beneath the surface,
it's a different story.
The Pacific plate and Asia
are colliding head-on.
Below the picturesque landscape,
the Pacific plate
is being driven under Asia --
a process called subduction.
lt makes Japan a hot spot,
not just for volcanoes,
but for earthquakes, as well.
Japan's volcanoes
look genteel...
but don't believe it.
lt's feared they'll destroy
the islands they once created.
lf we could take our capsule
deep below Japan,
we'd find that the volcanoes
aren't like the ones
we saw in Hawaii.
At Kilauea, the heat
and pressure of the deep Earth
blast out streams and
fountains of molten lava.
Under Japan,
there's a different driving
force beneath volcanoes --
subduction.
As subduction buckles and
breaks the Earth's crust,
sea water flows in.
Hot rock and cold water
are an explosive mixture.
Subduction triggers
earthquakes, too.
Tetsuro Urabe is a professor
at the University of Tokyo.
Eight years ago,
a quake killed 6,000 people,
including his mother.
He now works
on earthquake prediction.
The Japanese islands are located
on the western rim
of the Eurasian continent,
where the plate
of Pacific Ocean floor
goes down beneath
the island arc.
So that kind of active setting
makes all those
natural disasters,
like a volcanic eruption,
an earthquake.
ln 1 995,
there was Kobe earthquake,
which killed about 6,000 people.
But it was not predicted,
and all the seismological method
failed to predict
the earthquake.
[ siren blaring ]
Narrator:
To predict earthquakes better,
we have to know more
about their causes.
A capsule designed to travel
to the center of the Earth
could help.
lf we weren't in a hurry,
we could bury it
in the Pacific plate
and wait for a
few million years.
lt would end up under Japan,
courtesy of continental drift
and subduction.
The rock
we parked the capsule in
is solid but also moving.
Bernie: And this is
what the mantle does.
lt flows very, very slowly at
about a centimeter or so a year.
But like glass, if you hit it
with a hammer, it breaks.
Narrator: And that's
what causes an earthquake.
one plate tries to
move against another.
lncredible pressure builds...
until one slab breaks and slips.
[ siren blaring ]
Because of its
unstable foundations,
Japan has one
of the most comprehensive
networks of earthquake sensors
in the world.
listen out for a
hint of movement
in the crust and mantle.
The data is beamed back
to a national monitoring center
that records every
tiny moan and groan.
Every quake, however small,
is mapped in three dimensions.
The quest is to find a pattern
that will predict future quakes,
because Japan is due
another big one.
lt's expected here --
Tokyo.
Tokyo has a population
of over 1 2 million.
Every 200 years,
this area is hit
by a huge earthquake.
The city is built
over a busy intersection
where four of the
Earth's plates meet.
The subterranean
collisions never stop.
That's why Japan's so prone
to earthquakes,
and why it's so hard
to see them coming.
lt's a high-stakes game.
Millions could be
hurt or killed.
To get better data,
they will have to drill down
into the colliding plates,
more than 6 miles.
JUDGE stands for
''Japanese Ultra-deep Drilling
and Geoscientific Experiment.''
That is to drill
about 1 0-kilometer hole
down to the subduction zone.
Narrator: They've chosen a site,
but what about the technology?
Urabe: The target area of the
JUDGE project is very active,
and, probably, the temperature
could be more than 300 degrees
at the depth of 1 0 kilometers.
And then the 300 degree
makes every operation
of the drilling very difficult.
Narrator: And that's the same
for our capsule.
We'd need more technology
for it to survive the intense
temperature and pressure.
What will the capsule find
at the center of the Earth?
A mammoth nuclear reactor?
Narrator: On its way
to the center of the Earth,
our capsule will have to
navigate a sea of molten iron.
Surging around the inner core,
this generates magnetic energy.
Just 1 % of it
escapes from Earth,
but that's enough
to form a protective shield
But how is so much
energy produced?
As Jeremy Blo xham admits,
we're still struggling
to find out.
Blo xham :
Really, the burning question
which we all wish to address
through our investigations
of the Earth's magnetic field,
is how is the field generated?
What is the mechanism
that gives rise to a field
which has persisted
for at least 2 billion years?
Narrator: One geophysicist
has a radical suggestion.
Marvin Herndon speculates that,
at the center of the Earth,
we may find
a natural nuclear reactor.
One of the problems
that has existed in science
is figuring out what
is the energy source
that drives the
Earth's magnetic field.
Narrator: He doubts
that it's just a ball of iron
that's been cooling
for 4 1 /2 billion years.
There's simply so much power --
enough to maintain
the magnetic shield,
move continents, and make
volcanoes and earthquakes.
Herndon suspects
there's something
much more powerful down there.
Herndon : One of the implications
that l suggested early on
was the possibility
that the changes
that we observe
in the geomagnetic field
may have their origins
in changes in the output power
of the nuclear reactor.
Narrator:
Could this explain
the drastic changes
our planet has gone through...
like the extinction
of the dinosaurs?
Could the melting
of the ice caps
have been caused by a surge
of heat from a nuclear core?
Because unlike an iron core,
a nuclear one can fluctuate.
Herndon :
Our nuclear reactor
can shut itself down
and start itself up again.
lts output can vary
or it can remain very constant.
Narrator: Herndon's ideas
are controversial.
Few agree with his theory,
and the debate continues.
But one thing isn't disputed.
The magnetic field is changing,
and measurements show it's
been doing so for some time.
Lathrop: Based on the results
and our current systems
that are sort of, you know,
basketball-sized,
then we have this plan
for a much larger system
that would be
filled with liquid sodium.
So about 1 5 tons of the metal.
But it would be driven
the same way
as the existing experiments,
but then at parameters that are
much closer to the parameters
thought to exist in the
interior of the Earth.
The capsule we built to journey
to the center of the Earth
is under its own power after
hitching a ride in the rock.
Now sensors show
the going is about to get tough.
the capsule nears the boundary
between the mantle
and the outer core.
The huge temperature here
melts away the remains
of the tectonic plate
surrounding the capsule.
Now the capsule must be
released from its protection
and power itself.
The capsule drives forward
through the liquid outer core.
Now it must cut its way
into the solid inner core.
lt's solid because
there's massive pressure here --
than at the surface.
And a billion amps
of electricity
surges between the cores.
This, at last,
is our journey's end --
the center of the Earth...
the only place on our
planet with no gravity.
[ bell ringing ]
Jules Verne's influence
on the world has been immense.
He propelled generations
of young readers
toward careers in science,
engineering and exploration.
He inspired the inventors
of the helicopter,
the submarine, and the radio.
There's little doubt
that his novels
influenced the minds
that have changed our world.
Little did anyone know
when Jules Verne died
at the dawn of the 20th century,
that he would have
such an effect on the future.
His life is summed up in
the inscription on his tomb --
''Onward to immortality
and eternal youth.''
lf Jules Verne was right,
maybe one day we will be able
to journey to the
center of the Earth.