Original subtitles

BRIAN COX: The natural world is beautiful but complex.

The skies dance with color.

Yay! Yes!

COX: Shapes form...

And disappear.

(CROWD CHEERING)

But this seemingly infinite complexity is just a shadow of something deeper,

the underlying laws of nature.

(HORSE WHINNYING)

The world is beautiful to look at

but it's even more beautiful to understand.

(BIRDS CHIRPING)

GIRL: Watch out for the brambles.

It's a fact

and one of the great mysteries about our universe

that everything is made out of a few simple building blocks

that interact with each other

according to a few simple laws of nature.

And that applies to everything.

Stars and planets and galaxies and rocks and oceans

but also to living things.

And that raises an intriguing possibility.

By looking carefully at nature, by doing science,

we might be able to understand what life is.

And, just perhaps, how it began.

The origin of life

is one of the great unsolved scientific mysteries.

BOY: Let's go over to the tree, there might be some over there.

Its origin seemed to be lost in the mists of time.

BOY: I've got a really pretty one here.

But in common with many scientific mysteries,

there may be answers,

if you ask simple questions.

Why do moths like flying into the light so much?

Do they do it because...

So they can spread out their wings and get warm?

COX: What's the deepest question you can ask about a moth?

I think it's, "How did it come to exist in the first place?"

We can't go back to the origin of life on Earth.

We don't have a time machine.

But we do have the moth,

and every living thing on the planet today.

And these are like little history books.

Their story of four billion years of life on Earth

is written into every cell in its body.

So, in order to discover the spark of life,

the origin of the flame,

we just have to learn to read the book.

(CHUCKLES) He's gone.

Living things are far too complex to understand in one go.

So we have to break the problem down

into simple questions.

What are the ingredients of life?

How does complex life form from such simple ingredients?

(EXCLAIMING)

And what was the driving force,

the energy source that ignited the flame

four billion years ago?

For the first 500 million years of Earth's history,

there was no life,

just the volcanic violence of a restless young planet

and the bombardment of countless meteorites from space.

But somewhere, somehow,

the ingredients of the planet were transformed.

Inanimate became animate,

and once ignited, that spark has never been extinguished.

We're searching for our ancestor from a time when there was no life.

If we are to understand how life emerged from the ingredients

present on the young Earth,

we must first explore what those ingredients are,

what the Earth is made from.

(WIND WHISTLING)

There are very few places on our planet

where the pure ingredients of the Earth can be seen.

But here, beside a lake of sulfuric acid,

one of the basic building blocks of the planet

boils to the surface.

This volcano delivers a valuable pure substance.

Sulphur,

emerging at over 200 degrees Celsius.

It's an alien-looking cauldron of chemistry.

(MAN SINGING)

Bagio and his father Boudie go to work on the volcano every day.

They labor to protect the precious pure sulphur.

(BOUDIE SPEAKING INDONESIAN)

(BOUDIE SPEAKING INDONESIAN)

COX: This crater is a working sulphur mine.

Sulphur is valuable

because it gets used in the manufacture of many products,

from sugar to medicine.

But keeping the sulphur pure is not easy,

because it readily catches fire and transforms into sulphur dioxide,

a noxious gas.

Bagio and Boudie are here to fight the fires.

(SPEAKING JAVANESE)

(BAGIO SPEAKING JAVANESE)

(BOUDIE SPEAKING JAVANESE)

(WIND WHISTLING)

COX: It's rare to find the elements in their pure form

because they tend to react with other elements.

In the heat of the volcano, sulphur reacts with oxygen in the air.

It burns.

Sulphur burns blue.

Working in the dark,

the fire fighters can see the flames clearly.

And it's their job to prevent them from spreading.

(SPEAKING JAVANESE)

(MEN LAUGHING)

(BAGIO SPEAKING JAVANESE)

(BOUDIE SPEAKING JAVANESE)

COX: Sulphur is an element that is essential to life.

All living things need it.

(BOUDIE SPEAKING JAVANESE)

But here, in such large quantities, ignited by an active volcano,

it becomes toxic.

(BAGIO SPEAKING INDONESIAN)

On contact with water in the eyes and mouth,

the gaseous sulphur dioxide from the flames

turns into sulfuric acid.

(BOUDIE SPEAKING JAVANESE)

(EXHALES)

(BAGIO SPEAKING JAVANESE)

(BOUDIE SPEAKING JAVANESE AND INDONESIAN)

COX: Sulphur is one of the 92 naturally occurring chemical elements.

There's no difference between the sulphur in the wings of a moth

and the sulphur that pours out of a volcano,

or the sulphur in you and me.

We're made of the same stuff as our planet,

and there's no mystery in that.

It has to be so because life emerged from the planet.

(BIRDS CHIRPING)

Hydrogen atoms, carbon atoms, oxygen and sulphur atoms...

These basic building blocks react and combine

to make everything.

A woodland is a complex place.

There are oak trees, and grass, and mosses, and ferns,

countless animals and plants

all living together in a tangled ecosystem.

But there's a simpler level of description.

Everything is made of atoms.

So, an oak tree is really just carbon, nitrogen, oxygen and hydrogen

and a few other bits mixed together.

So, when you look at it like that

it's not really that complicated at all.

The atoms that make up this woodland

have been on an extraordinary journey to get here.

Think of a carbon atom in this acorn.

It was assembled in the heart of a star billions of years ago,

out of protons that were built just after the Big Bang.

It got thrown out into the universe in a supernova explosion,

collapsed as part of a dust cloud to form the sun

and then the Earth, 4.5 billion years ago.

It will have spent a lot of time in rocks.

It was probably part of some of the first living things on Earth.

It would have got breathed out as carbon dioxide

by someone that walked through this wood 400 years ago.

It will have got into some ancient oak tree

through the action of photosynthesis,

constructed into this acorn, fallen down to the ground,

and there it is.

It's got a history that goes back billions of years.

In fact, a history,

in terms of the building blocks of carbon,

the protons,

that goes back right to the origin of the universe.

And in billions of years' time,

when the sun dies and the Earth is vaporized,

it'll be thrown back out into space and probably condense into a new world

billions of years in the future.

So, life is just a temporary home

for the immortal elements that build up the universe.

The atoms are building blocks, they combine to make molecules,

some of which are terrifically intricate and complex.

The DNA molecules in the cells in your body

are made up of billions of atoms linked together,

carrying the genetic code to make you.

Exactly how this complexity emerged is still debated.

But everyone agrees on one thing,

there was a very special theater from which biology emerged.

The vital ingredient for life...

And these children know where to find it.

(BOYS SPEAKING SPANISH)

(BOY SPEAKING SPANISH)

COX: The elements hydrogen and oxygen combine to make water, H20.

Hidden deep in this forest

is a rare and magical sight

that only exists because of a unique property of water,

a property that makes it essential to life on Earth.

Biologist Tom Isley has brought a specialist team here to find it.

ISLEY: This limestone is fantastic here.

The way it's pockmarked and dissolved away

indicates that there's a lot of water moving underneath.

MAN: We're going to kill ourselves if we go down that way.

ISLEY: Yeah, it's slippery. We'll slide on our ass.

MAN: We'll go that way, yeah.

COX: Only a handful of divers

have the skill to explore this network of caves.

MAN: So, you're gonna need those two and this one, yeah?

ISLEY: Yeah.

ISLEY: These caves are one of the last true, undiscovered, unexplored,

unknown frontiers on the planet Earth.

Very few people, very few scientists,

go out and do anything any more dangerous

than what we are doing in cave diving.

COX: This underground cave system exists

because water, the liquid we drink, can eat through solid rock.

It makes easy work of the soft limestone

and makes things exceptionally fragile.

ISLEY: The worst thing is your tanks may wedge in

and literally stick you in a spot

where you can't move forward or backward.

(TANK CLANKING)

A little bit distracting,

when you're trying to do something underwater,

to have the cave collapsing in on you.

MAN: Hey, there, welcome back. Glad to see you.

Oh, man, that tight spot in there,

I could barely fit through.

Even worse, there's, like, rocks that get dislodged.

Erm, when they fall down, it rains down like huge amount...

I say we leave it, like, 24 hours at least, so it clears up.

- OK. OK. - And then come back, give it another go.

You're gonna lose your own visibility within seconds.

So there is not much time to stop and hover and think.

ISLEY: The reason why we go through these narrow slots,

why we push our bodies to the limits,

is to find something majestic, something beautiful on the other side.

But unless you go there, unless you look,

you're never gonna know.

COX: Deeper into the cave system, suddenly the water changes.

Underneath the forest, miles from the coast,

they found the ocean.

It's able to flow underground,

working through the pores and fissures in the limestone

to end up here,

where the denser, salty sea water sinks below the less dense, fresh water,

creating a boundary,

a beautiful phenomenon known as a halocline.

ISLEY:. Now we're in sea water,

we've reached the ocean, the underground ocean, in planet Earth.

We can see the movement of water,

fresh water going toward the ocean, salt water being sucked inland.

COX: Water dissolves more substances than any other liquid.

It does this because it's a polar molecule.

It has positive and negatively charged regions,

and these can disrupt the forces that bind other molecules together.

Bacteria that line the cave walls

feed on the nutrients dissolved in the water.

ISLEY: You can see these stringy bacteria hanging down

and they kind of wave in the breeze as you fly by.

COX: The bacteria, in turn, are food for other life.

Even in these dark, isolated environments

with no direct sunlight to power it,

a complex ecosystem can be supported.

It's why, as far as we know,

where there's water on Earth there's life.

(BOY LAUGHING)

(INDISTINCT CONVERSATIONS)

(SPEAKING SPANISH)

(BOY SPEAKING SPANISH)

(SPEAKING SPANISH)

COX: Our blue planet is an interconnected matrix

of rivers and oceans,

transporting the dissolved ingredients of the Earth

that are integral to life.

The salts and nutrients that are carried around our planet

are also transported through our bodies in water.

It's an intimate connection that every living thing shares

with our blue planet.

Water delivers the ingredients of life.

Water is a simple molecule,

a couple of hydrogen atoms and an oxygen atom stuck together.

But its simplicity hides a wealth of complex chemistry,

the chemistry that makes life possible.

Hydrogen is the simplest chemical element.

Its atoms consist of a single proton,

it's called the atomic nucleus, surrounded by a single electron.

Oxygen is a nucleus of eight protons and eight neutrons,

surrounded by eight electrons.

Now, the nucleus is extremely small, compared to an atom.

If the nucleus, er, were about that big, let's say,

then the cloud of electrons

would stretch out way beyond that castle.

I mean, atoms are almost completely empty space.

Now, the way that the elements combine

is determined entirely by the way that the electrons

arrange themselves around the nucleus.

And that's just down to the basic fundamental laws of nature

that describe the way our universe is constructed.

It's very simple.

So, an oxygen nucleus

has room around it for 10 electrons,

but it only has eight.

That means that two hydrogen atoms can come floating in

and share their single electron with the oxygen

and that fills up the oxygen's outer slots,

and fills up the hydrogen slots, as well.

Oxygen, hydrogen, H20.

Everything is happy and you get a molecule of water,

which has radically different properties to the elements on their own.

Oxygen's just a colorless, odorless gas.

Hydrogen is a colorless, odorless gas.

Stick them together to share those electrons

and you get that stuff,

one of the most complex substances in the known universe,

the theater that allows life to exist.

Water is the universal solvent.

It carries the ingredients of life,

ingredients that are so important

that living things will go to extraordinary lengths

to get hold of them.

- It's the end of the Alpine winter. - (IBEX BLEATING)

This female Ibex has one thing in mind.

(IBEX BLEATING)

Kids.

She's leading her family down from the snowline

in search of a life-giving ingredient.

And it's a search that's not without its risks.

Rada Bionda is a conservationist, who studies the ibex.

(BIONDA SPEAKING ITALIAN)

(IBEX BLEATING)

(IBEX BLEATING)

COX: At first glance, the ibex have everything they need.

They have food and water

but the mother knows instinctively, not enough.

She's craving something else and she'll take risks to get it.

The rock that was used to build this dam

contains essential minerals that have been dissolved in water,

minerals rich in the calcium that these animals need to stay strong.

And they'll scale a dam to get them.

(BIONDA SPEAKING ITALIAN)

COX: Without these salts and minerals, their bones won't grow,

their nervous systems and muscles can't function.

Movement and co-ordination can falter.

(SPEAKING ITALIAN)

(IBEX BLEATING)

COX: There's a strong bond between mother and kid,

and the kid will follow her wherever she goes.

(IBEX BLEATING)

(BLEATING)

(BLEATING)

(BLEATING)

The ibex eventually make it to the prize.

Salt from the earth, dissolved in water,

continues on its journey into their bodies,

where it's used in the nerves and muscles

that control dexterous, pincer-like hooves.

Vital ingredients,

carried around by a simple molecule with remarkable properties.

If water is the theater of life,

then the actors are the atoms and molecules

that form the structures of living things themselves.

There are only about 15 or so

that are vitally important for living things.

There are the obvious ones like carbon, nitrogen, oxygen.

But also some strange ones,

like rubidium, or an element called molybdenum.

The reactions between the elements are the same

in living and non-living things.

But life fine-tunes and controls the basic chemistry of the Earth

to do extraordinary things.

(MOISWAR SPEAKING OWN LANGUAGE)

(SHEEP BLEATING)

(MOISWAR SPEAKING OWN LANGUAGE)

COX: Moiswar and her family

are preparing for a once-in-a-lifetime ceremony,

centered around the chemistry of one element.

Iron.

It lies at the heart of Maasai culture, in their land and in their blood.

(SPEAKING OWN LANGUAGE)

- (BABY CRYING) - (SPEAKING OWN LANGUAGE)

COX: Tomorrow, Moiswar's son, Andika, will become an elder.

(EAGLES SCREAMING)

COX: The family are almost ready for their guests

but there's something they must first collect from the land.

(MOISWAR SPEAKING OWN LANGUAGE)

(INDISTINCT CONVERSATIONS)

COX: They're looking for red ochre,

a traditional pigment that's been in use for over 700, 000 years.

(MOISWAR SPEAKING OWN LANGUAGE)

COX: The rock's red color comes from iron,

which makes up a third of our planet's mass,

most of it locked away in the Earth's molten core.

(MOISWAR SPEAKING OWN LANGUAGE)

COX: The iron here is not in its pure form.

It's combined with oxygen to form iron oxide,

a red compound that tomorrow will provide the color of celebration.

(SHEEP BLEATING)

(MOISWAR SPEAKING OWN LANGUAGE)

- (SPEAKING OWN LANGUAGE) - (LAUGHING)

(BOTH LAUGHING)

COX: This is the ceremony

that will mark Andika 's transition into elder-hood.

A bull will be slaughtered

and he'll drink its blood.

Just like the red ochre from the earth, the blood is rich in iron.

Today for Andika, blood symbolizes power and strength,

surrounded by his people, decorated in ochre, iron oxide.

(MOISWAR SPEAKING OWN LANGUAGE)

(MAASAI SINGING)

COX: It's a proud moment for Andika and his family.

Wherever there is iron and oxygen, they can react,

whether it's in the veins of the Earth or the arteries of life.

(SINGING CONTINUES)

(BOTH SPEAKING OWN LANGUAGE)

(MOISWAR LAUGHING)

(MAASAI SINGING)

COX: Whether it's in you and me or the rocks of the Earth,

the fundamental chemistry is the same.

But the way life uses chemistry is exquisite.

Just think about the reaction between iron and oxygen in blood.

And rust.

Iron is an atom

that really would like to, if it could, get rid of a few electrons.

Oxygen, on the other hand,

is an atom that would like, if it can, to receive some electrons.

So if you put them together and they stick together,

that's what we call rust.

And the process that makes our blood red is similar.

We're almost rusting, but not quite.

One of the jobs of your blood is to take oxygen from your lungs

and transport it around your body to where it's needed.

So that means you need some structure that can bind oxygen to it,

but quite gently,

so that it can be carried to where it's needed

and then released easily.

Well, iron likes to stick to oxygen, so in your blood you have iron atoms.

But they're surrounded by nitrogen atoms,

four of them.

And that's surrounded by a big ring of carbon and oxygen atoms.

That whole thing is called haem,

and then four of those are stuck together

and that thing's called hemoglobin.

Its job is to carry oxygen around.

When the oxygen attaches, your blood turns a much brighter red.

And then the hemoglobin can carry that oxygen around.

But because of that structure, it's so delicately tuned

that when the oxygen gets to where it's needed,

in your brain for example, it can be taken off.

Your blood gets less red

and goes back to your lungs to get some more oxygen.

So, biology is really about using

the natural chemical reactions of the elements,

but tempering them and fine-tuning them with intricate and complex structures,

in order to do something useful,

which in your case is to live.

We are of the Earth,

constructed from a ready supply of chemical elements,

forged in the stars.

Elements that react on our oxygen-rich planet

and play their roles in the theater of life,

water.

But there's one more vital thing life needs,

energy.

The final clue we need to search for the origin of life

can be found in the details of how living things control energy.

Every year, between March and June, an animal rises from the deep.

It harnesses the chemistry inside its cells

to produce an almost supernatural display.

For the locals,

this alchemy makes the creature a delicacy.

But for fishermen, like Mr Urakami, it makes them highly profitable.

(URAKAMI SPEAKING JAPAN ESE)

COX: Mr Urakami is banking on this being

the most lucrative catch of the year.

And it's not fish he's after.

(ALL SPEAKING JAPANESE)

COX: Away from the fishing boats, these people are having a bit more luck.

Glowing lights signal the arrival of the firefly squid.

Tiny organs called photophores emit a deep blue light.

In the depths, this light may be used to attract prey.

But the greatest light show is saved for the shallows,

where they come up to spawn.

(MAN SPEAKING JAPANESE)

(WOMAN SHRIEKING)

COX: It's a one-way trip.

After they've spent their last remaining energy,

their glow fades as they give themselves up to the tide.

Out at sea, the squid are also rising.

(URAKAMI SPEAKING JAPANESE)

(URAKAMI SPEAKING JAPANESE)

COX: The squid are exploiting something fundamental.

Chemical reactions can release energy.

Here the energy is released thanks to the reactive nature of oxygen.

It wants to combine with other elements in a reaction known as oxidation.

In the squid, biological molecules called luciferins,

built out of simple elements like carbon, sulphur and nitrogen,

react with oxygen to form oxiluciferin.

When that process releases energy, there's a blue light.

(MAN SHOUTING IN JAPANESE)

COX: An exquisite display.

(MAN SHOUTING IN JAPANESE)

(SPEAKING JAPANESE)

COX: For Mr Urakami, this is the spectacle he lives for.

(URAKAMI SPEAKING JAPANESE)

COX: It's a rare and beautiful sight in nature.

But the chemistry of oxidation is fundamental to all animals.

There's a reason we breathe oxygen.

It fuels the chemical reactions that power us.

They release the energy to build and maintain

the complex structure of our bodies.

But it's the precise way life controls this flow of energy

that's the difference between a volcano and a squid,

between raw chemistry and life,

between a moth and a flame.

GIRL 1: See, that one looks like an old man.

GIRL 1: That one there. GIRL 2: Oh, that's nice.

(LAUGHING)

COX: Moths and flames always seem to go together.

And in fact, in a basic chemical sense, they're very similar.

Candle wax is essentially food.

It's a collection of long-chain carbon molecules.

And in the candle,

that food reacts with oxygen to produce carbon dioxide, water,

and release energy, which is the flame.

Inside the moth, exactly the same thing is happening.

Food is reacting with oxygen to produce carbon dioxide and water,

and release energy, the energy that powers life.

That's called respiration.

It sounds quite simple.

We burn our food to release the energy we need to live.

What do moths eat in the winter?

COX: It's not that simple.

But simple questions lead to the deepest answers.

In this case, to the origin of life.

The moth doesn't use the energy released from food directly.

It does something way more complicated.

It uses that energy to pump protons,

the building blocks of atomic nuclei, across membranes.

Billions of them.

And so do you.

And so does every living thing on the planet.

In the time it's taken me to say this sentence,

you have pumped more protons across membranes

than there are stars in the observable universe.

And then all those protons are allowed to cascade back down proton waterfalls,

and little nano machines with little water wheels

stick into that waterfall and spin around,

and produce molecules called ATP,

which are the universal batteries of life,

which are then finally used to power your biology.

It is incredibly complicated and, to be honest, a bit weird.

This complicated and weird chemistry

powers practically every living thing on Earth.

But it had to start somewhere.

And it may have begun before there was life.

There is a place where this strange chemistry exists today.

But not in a living thing.

This may be the clue to how you get from the Earth

to you and me.

This fjord in Iceland is one of the few places on Earth

where you can see how life could have emerged

from a restless young planet.

BOGASON: My next-door neighbor was this old lady,

telling me the stories about the things she saw from the sea.

I have been diving there many times, so I knew this place.

I didn't believe this old lady.

COX: Curiosity drove diver Erlendur Bogason

to an extraordinary discovery.

BOGASON: So, I called my friend Arm} the fisherman,

and asked him to take me to this place.

(LAUGHING)

(BOTH SPEAKING ICELANDIC)

COX: Biologists knew of places

where the chemistry of life emerges from the Earth.

But they're all thousands of meters below the surface of the ocean.

These two men stumbled on a place where you can literally touch it.

BOGASON: I was, like, stressed because you are going alone somewhere to dive

and you don't know what you are going to find.

And when I just see this huge, white thing,

it looked like a giant.

It was an unbelievable sight.

Wow! It's beautiful. It's something incredible.

COX: Erlendur had discovered a hydrothermal vent.

But unlike those in deep ocean, you can swim right up to this one.

The vent is an outpouring of fresh water

that's been heated by Iceland's geothermal energy.

BOGASON: I took my glove off, put my arm into hot water,

it was, like, burning hot.

COX: By studying vents like these,

scientists discovered that the chemistry of life

exists in a non-living thing,

in the Earth.

BOGASON: I called this scientist and told him about this.

We went back for him to take water samples.

COX: To create a spark of life,

all you need is a battery with a flow of charged particles,

in this case protons.

And to power the battery you need nothing more

than water from the vent and some sea water.

Thank you.

To show it works,

you just need to connect it all to a voltmeter.

And that is the spark of life.

Now, why would I say that?

Well, this water, taken from the vents,

is alkaline.

And this sea water is relatively more acidic.

That means that there's an excess of protons

on this side of the battery than this side.

And there's that waterfall, that cascade of protons.

The same thing that's happening in the cells in your body,

in the cells in the body of seagulls,

and, in fact, the cells in the body of every living thing on the planet.

Waterfalls of protons powering life.

And that's the clue. That's the smoking gun.

The theory is that the chemistry of life,

the beginnings of the assembly of complex molecules

all the way up to the first living things,

to DNA and everything we think of life today,

was built, was constructed, in conditions like this.

The waterfall, the cascade of protons,

is the driver of complexity, the spark of life.

It's the exquisite control of the proton waterfalls

that separates life from chemistry, the moth from a flame.

So just spare a thought for what your body is doing now.

I mean that sandwich you just ate before watching this program,

you're burning that in oxygen, it's the oxygen that you breathe in.

But you are not using the energy that gets released directly.

You're using it to pump protons around.

You pump them across little membranes,

creating a voltage, about 30 million volts per meter,

in the cells in your body.

That's the voltage of a lightning bolt.

That's the spark of life.

And that's the clue that tells you the origin of you.

The most distance ancestor of you wasn't a living thing at all.

It was a geological thing.

It was most likely to be a vent, like the one we're floating over now,

in some ocean four billion years ago.

The very earliest life of our planet.

From a sandwich to a bolt of lightning, you are a remarkable machine.

For me, this theory of the origin of life

is the perfect example of the power of science.

It's a grand, sweeping idea that comes from exploring in detail

the way that living things control their energy.

Look, it's slightly vibrating its wings.

COX: From asking questions

like, "What's the difference between a moth and a flame?"

GIRL: This one's going for a walk.

(LAUGHING)

COX: But the answer is a wonderful story.

At this instant, in the cells in your body,

you're recreating the conditions that were present

in the oceans of the primordial Earth.

You are just chemistry.

But what chemistry!

The Earth is your ancestor and a restless planet is your creator.

(MUSIC PLAYING)