♪
Narrator: Since the dawn of humanity,
We have asked the question,
How did our wondrous home come to be?
Today, space technology casts light on this mystery.
Thanks to intrepid astronauts
And data beamed from hundreds of satellites,
We are gaining new insight into earth's epic history.
Woman: Going to space,
We have a different lens to look at the whole planet.
Narrator: We're finding fresh evidence
To answer age-old questions
About the formation of our solar system.
Man: We can only understand the big picture
When we study all these bodies
And learn everything they have to tell us.
Narrator: We're asking how life begins
And how it evolves through times of peril.
Man: All of these stories
Are intensely interesting murder mysteries
In our planet's past.
Narrator: We're going on a 4.5-billion-year journey
Through eons of fire and meteor storms,
From the arrival of oceans
And freezing global ice sheets,
Through epic eruptions
And mass extinctions,
To where, against all odds, life finds a way.
♪
This is the story of the life of earth from space.
♪
[radio chatter]
250 miles over our heads orbits the international space station.
♪
The astronauts who live here
Constantly monitor the world below.
♪
Cady coleman: Our vantage point from space
Gives us a view of the planet
That is about collecting information
That can't be collected any other way.
Narrator: But they can also observe phenomena
That provide clues to earth's distant origins,
The countless tiny meteors bombarding our atmosphere.
Coleman: Every single day,
There are thousands and thousands of pounds
Of space rocks pummeling the earth,
And it becomes very clear that we live in a neighborhood.
It's made up of pieces of the universe,
Some of which come crashing down onto our earth.
Narrator: As they enter the atmosphere,
Most of these space rocks burn up,
But those that don't
Can help us understand where our planet came from.
♪
50,000 years ago,
A large meteor punches through the atmosphere.
The impact site is today visible from space--
Arizona's barringer crater.
When the 30-ton meteorite hit,
It exploded into thousands of pieces.
At the national museum of natural history,
A major fragment is on display--
The canyon diablo,
One of the oldest objects you'll ever see.
Radiometric dating reveals its oldest parts
Formed almost four and a half billion years ago.
Hakeem oluseyi: These meteorites hold in them
A history of our solar system.
They're sort of like fossil relics
That have a story to tell about the birth of earth.
Narrator: It's a story that starts with the building blocks
Of everything on earth,
Elements that are forged in the hearts of long-dead stars.
♪
Under its own gravity, an enormous star collapses.
♪
[explosion]
The explosion creates elements like iron, oxygen, and carbon.
Oluseyi: The materials that we're made of,
The materials that everything around us is made of,
That earth is made of, these materials, these elements,
Are created in the centers of stars,
And so we are made up of the ashes of exploding stars.
Narrator: As gravity pulls on the stardust,
It forms a hot, spinning disc.
A new star grows in its center-- our sun.
Around it, hot, dusty materials clump together.
These small masses will become comets, asteroids, or meteors,
Like the canyon diablo.
The largest of them become planets, like our own.
♪
The infant earth is born.
Its surface is a hellish ocean of molten rock,
And it's missing a crucial companion.
For humanity,
The moon has always been a source of wonder...
A timepiece to chart the months and seasons.
Modern scientists are also captivated
By our closest celestial neighbor.
For them, it is the moon's origins
That remain the greatest mystery.
Is it a smaller body formed in parallel with the earth
Or a passing planet captured by earth's gravity?
♪
Nasa's apollo missions provided a unique opportunity
To find the answer.
December 1972, the launch of apollo 17.
On board is dr. Harrison schmitt.
On this last mission to the moon,
Nasa sends their first geologist.
♪
Man on radio: 25 feet. Down at 2.
Feels good. 20 feet.
10 feet.
Engines stopped. Ok, houston, the challenger has landed.
Narrator: Scientists believe the secret to the moon's origins
May be hiding in its rocks,
If they can identify the right ones.
Harrison schmitt: My mission was a little bit different
Because we built in some time for me,
As a geologist, to look around
And try to understand more than a pilot astronaut--
However well-trained they might be,
They didn't have the experience that I did.
Astronaut: Let's see if I can't crack the corner
And get that contact.
Schmitt: We actually collected more than any other mission,
About 240 pounds of rocks.
Narrator: With his carefully selected specimens,
Schmitt hits pay dirt.
These rocks prove that the earth and moon
Are more than just neighbors.
Oluseyi: What those rocks showed is that the moon was made up
Of pretty much the same stuff as the earth,
And so that gave us the big clue that we needed
To understand how the moon formed
But also understand the early history of earth.
Narrator: It's now widely believed that the moon
Is the remnant of a catastrophic collision.
♪
A newly formed planet the size of mars
Heads straight towards the infant earth.
♪
From the molten debris, our moon takes form,
The same size as it is today, but 17 times closer.
Oluseyi: It took a lot less time to orbit the earth,
And it took a lot less time
For the earth to spin once on its spin axis,
So the day was shorter, the month was shorter,
The week was shorter.
♪
Narrator: The proximity of this large circling object
Distorts the earth, causing a tidal effect in the rock.
Oluseyi: There was a gravitational interaction
Between the earth and the moon that we call the tidal force,
And that has the effect
Of throwing the moon away from earth,
So every day,
The moon moves a little bit farther away from the earth
Than it was the day before.
♪
Narrator: Now, as the moon rises for the first time,
Our planet begins to cool,
And a crust begins to form.
But before earth can truly come to life,
It must survive another harrowing challenge from space.
♪
Narrator: The moon's barren surface
Bears the scars of the distant past.
In 1972, in the rocks around their spacecraft,
Harrison schmitt and the crew of apollo 17
See signs of an impact so intense,
It melted the moon's crust.
They'd landed inside an enormous crater 400 miles wide.
Schmitt: We were in a valley
Deeper than the grand canyon of the united states,
So it was really a remarkable place to be.
Narrator: The crater is one of many thousands
That dot the moon's surface,
And analysis of apollo rocks reveal
Many of these epic craters are truly ancient,
Evidence that beginning some 4 billion years ago,
The inner solar system suffers an intense bombardment.
Schmitt: The major thing that we have learned
Is that the first billion years of earth's history
Was extraordinarily violent.
♪
Narrator: Across hundreds of millions of years,
The earth is hit by over 22,000 asteroids and comets
From the outer solar system.
Some are over 25 miles across.
Each one inflicts cataclysmic destruction.
[explosion]
Oluseyi: What would that feel like?
Constant earthquakes,
Objects are streaking through the sky, falling to earth.
You feel the ground shaking,
Giant plumes of material being thrown up.
That would have been amazing.
There is lightning that's created in the plume of dust.
There are rocks that are falling and look like they're on fire.
There's going to be a lot of molten rock
On earth's surface, as well.
You think of darkness. You think of lava.
You think of the smell of sulfur.
Narrator: As this assault continues,
The earth's appearance changes.
Water starts to pool on the earth's surface.
It's thought that the comets bombarding earth
Are laden with ice.
This combines with water
Leaching from the earth's own cooling rocks.
♪
The first oceans are born.
With water comes weather.
♪
1,000-year relentless storms of unimaginable ferocity.
[thunder]
♪
Every tide like a mega tsunami.
Oluseyi: The moon was much closer to the earth,
And this means that the tides were much greater,
So instead of measuring tides in feet,
Tides were measured in kilometers or miles.
♪
Narrator: 4 billion years ago,
500 million years after the earth was born,
It has a moon, oceans, and weather.
It is beginning to resemble the planet we know.
For now, it is barren, devoid of life,
But things are about to change.
2013, chelyabinsk, russia.
A traveler arrives from deep space.
♪
[crash]
[screaming]
[crashing]
It is the largest meteorite impact in a century.
The hunt is on to find its scattered remains.
♪
Scientists pull a huge fragment from a nearby lake.
♪
They cut it open and make a fabulous find.
The space rock contains primitive organic materials.
♪
It's the latest evidence to support a growing idea--
That the same comets and meteors that carried water to earth
Also brought with them the ingredients for life.
4 billion years ago,
Auroras illuminate the infant atmosphere,
The visual manifestation of the earth's magnetic field
Produced by its molten core.
It's a shield that now protects the surface
From the ravages of space radiation.
♪
Beneath this shield,
In shallow coastal seas churned by the tides of the moon,
Fueled by volcanic heat
And seeded with organic molecules from space...
Comes the very first life on earth.
♪
Just how it begins remains a mystery.
But at some point in this distant time,
Chemistry becomes biology.
♪
For years, no one believed life could exist
In toxic volcanic environments,
But life is full of surprises.
Today our planet is much changed,
But there remain some environments
Bearing similarities to early earth--
Iceland,
One of the most volcanic regions of earth.
Just off its southern coast
Lies an isolated volcano named surtsey.
♪
Surtsey is one of earth's newest strips of land.
♪
In 1963, it exploded from the sea,
Erupting continuously for four years.
♪
It is now a world heritage site,
Off-limits to all except a few research scientists.
Surtsey's hot volcanic cracks and seams
Closely reproduce the environment of early earth.
The team drills cores of rock from hundreds of feet below.
♪
They search for the fingerprints of life,
Marks made in the rock by deep-dwelling microorganisms.
♪
Despite temperatures exceeding 250 degrees fahrenheit,
Without oxygen, and in acidic, salty water,
The rocks are clearly scarred
By single-celled organisms feeding off the rock.
Scientists are now finding these extremophile cells
In volcanic zones across the globe.
Steffen jørgensen: It's mind-blowing, to be honest,
Because the number of microbial cells found in this system
Outcompete the number of stars in the universe.
Narrator: Dna indicates some underground microbes
Relate closely to cells that were ancestors
Of all life on the surface.
Jørgensen: It dawned on me at that time
Just how important they are.
These are the type of cells
That evolved into a more complex cell structure,
Which eventually turned into you and I.
♪
Narrator: 3 billion years ago,
Simple single-celled life forms are now colonizing the planet.
The oceans swirl with blue-green cyanobacteria.
♪
These have now evolved
To harness the energy of sunlight...
Through photosynthesis,
The process still used by modern plants.
This revolution in energy supply has massive consequences...
Because the byproduct is oxygen.
Over the next billion years,
Cyanobacteria turn carbon dioxide into oxygen
In such volumes that the entire ecosystem alters.
The crust of the earth and the oceans are filled with iron.
As oxygen leaches into the system,
This iron is transformed.
Kirk johnson: There's lots of iron on the planet's surface,
But it had never been oxidized before,
So, fundamentally, cyanobacteria created oxygen,
Which created rust, and the earth became red.
♪
Narrator: By 2 billion years ago,
The countless tiny microbes that fill the earth's oceans
Alter the chemistry of the planet.
♪
But as it slowly evolves over the next billion years,
Life will face a new challenge to its existence,
As changes in climate
Plunge the planet into deep freeze.
720 million years ago,
Earth is set for an explosion of life,
But for now, life remains primitive and rare,
And some scientists believe they know why.
Satellite and ground surveys
Across a 2,000-mile stretch of northern canada
Capture evidence of an ancient continent-sized volcanic field.
This is the franklin large igneous province.
Many scientists now believe
It's the sign of a series of enormous volcanic eruptions
That threatened life on earth by blotting out the sun.
[rumbling]
1991, the philippines.
Mount pinatubo explodes.
It's one of the biggest volcanic eruptions of the modern era.
Pinatubo pumps over 10 million tons of sulfur into the skies.
Satellites later record a change
In reflectivity of the atmosphere.
So much heat energy bounces back into space,
The whole earth cools by one degree fahrenheit.
Imagine the impact of multiple pinatubo eruptions
All going off at once.
♪
Northern canada.
Across 2,000 miles, the earth tears open.
♪
Billions of tons of sulfur and ash clog the air.
♪
The earth plunges into darkness.
[explosion]
The eruption continues for decades.
♪
Global temperatures plummet to minus 50 degrees fahrenheit.
One theory suggests the freeze is so intense,
The planet is encased in ice--
Snowball earth--
Entombing earth's fragile microbes beneath miles of ice
For 80 million years.
♪
But eventually the ice thaws.
Somehow, life on earth survives,
And now it will thrive.
Across the next 200 million years,
New generations of bacterial blooms
Raise oxygen levels again,
Creating an atmosphere rich in oxygen.
Coleman: Looking at the earth, especially at sunrise or sunset,
Which for us happens 16 times a day,
Which is pretty wonderful,
That's when you can really see
That, that layer, that, that thin atmosphere,
And it's like a little bubble
That encloses everything you know and love.
Narrator: 600 million years ago, this oxygen-rich environment
Is the catalyst for an energy revolution.
Some microbes now turn from solar power to oxygen power.
This new energy source is behind their evolution
Into the first multicellular plants and animals.
Today, off the coast of australia
Lies the great barrier reef,
An organic structure so big, it can be seen from space.
♪
Scientists believe ancient reefs were incubators for early life.
They are among the most ecologically diverse places
On our planet.
♪
Johnson: Reefs are like cities.
I mean, cities, you start with a few little houses.
Then you get buildings and multi-story buildings.
There's lots of diversity in a city,
So in ancient reefs, there's just that same thing.
The more kinds of places there were to live,
The more diversity of life forms there were.
Narrator: In southern africa,
Scientists have recently discovered
What they believe is one of the oldest reefs on the planet.
It was formed in oxygen-rich seas 550 million years ago.
♪
Evidence suggests this is a time of rapid evolutionary change.
This is when the blueprint of modern animals,
Of us, first emerges--
The cambrian explosion.
Johnson: What we see are a bunch of new kinds of organisms.
Now, these were marine animals,
Small animals that looked like crabs and shrimp
And other kinds of shellfish.
These organisms had features that are quite familiar to us.
If you look at a, a little tiny crab,
He's got little eyes looking back at you.
He's got limbs, and he crawls around,
And he eats stuff through his mouth,
And it goes into his stomach,
And it goes out the back end as its waste.
That sort of way of being an animal,
We see for the first time in the cambrian explosion.
Narrator: Over 4 billion years,
The earth evolves from a ball of fire to a ball of ice.
And by 400 million years ago, to this--
A blue-green planet
With life spreading to the land.
Johnson: Pretty soon after you have the first plants on earth,
You have the first trees on earth.
With trees come forests,
And with forests come the same kind of diversity of habitat
That we've seen underwater in the reef structures.
Narrator: With plant life comes animal life.
The first surface dwellers make their appearance.
Life now has a foothold,
Across land, sea, and the sky.
But their new oasis
Is a time bomb just waiting to explode.
Russia.
These are the siberian traps,
An ancient lava field spread over 2 million square miles.
In 2011, scientists here made a crucial discovery,
Explaining one of the most infamous events
In earth history,
The great dying.
This spot is the scene
Of the most deadly volcanic eruption in history.
♪
This huge area becomes an ocean of fire.
♪
But the danger is not just the eruption.
Scientists found the lava erupted
Through a thick layer of coal,
Generating a toxic cloud that acidifies the atmosphere,
Leading to about a million years of deadly acid rain.
Johnson: This eruption happens almost precisely
When we see a lot of things go extinct at the same time.
The lava starts erupting, organisms start dying.
We call it the great dying because by our best estimates,
It's pretty close to snuffing out life on the planet.
♪
Narrator: But not all life dies out,
And the gaps opened up by the extinction
Generate a monstrous surge in evolution--
The age of the dinosaurs.
♪
Argentina, 2012.
♪
Paleontologist dr. Diego pol
Uncovers the remains of what's thought to be
The biggest land animal that ever lived.
So large, its thigh bone alone stood taller than a human.
♪
The 70-ton titanosaur.
Diego pol: Can you imagine 10 african elephants put together?
You know, this animal was as long as an airplane,
You know, a boeing 737.
Narrator: But dinosaurs were not always so enormous.
Pol: 230 million years ago,
The first dinosaurs appear on our planet,
And they were tiny animals.
They were probably weighing 10 kilograms.
Now, 50 million years after that...
[thud]
[roaring]
There were the first giant dinosaurs.
This is the time when titanosaur appeared
And when they achieved the maximum body size,
When we started seeing these 70-ton animals
Roaming on our planet.
Narrator: It's not yet clear
What caused dinosaurs like titanosaur to grow so large.
But these enormous plant eaters
Now become an important part of the global ecosystem.
They travel hundreds of miles.
They spread seeds and trample vegetation,
Creating new opportunity for plant species
To spread across the planet.
[roars]
Pol: We know these giant dinosaurs migrated
From antarctica to asia to north america, africa.
They were everywhere,
Roaming through the landscape,
Altering and modifying the different ecosystems
All over the planet.
It's really, really amazing.
Narrator: For 180 million years,
As the continents slowly shift beneath them,
The giant dinosaurs dominate the planet,
But around 65 million years ago,
Suddenly they disappear, wiped out by a meteor strike.
Scientists believe another event
May have contributed to their downfall.
In india today, there is a collection of ancient temples.
These incredible structures were cut from the soft rock
Of the deccan traps,
The remains of a massive lava eruption
That spreads over 200,000 square miles of western india.
♪
This epic eruption begins to poison the dinosaurs' world.
♪
But the nail in their coffin
Is the sudden impact of an immense meteor.
Johnson: Here you have a body of rock
That's six miles in diameter.
It's traveling at 20 times the speed of a rifle bullet.
When it hits planet earth,
Which is much, much, much larger,
It's like driving a truck into a stone wall.
And it punches a hole deep into the earth.
And then all that energy gets blown back out of that hole.
Narrator: With a force of a billion atomic bombs,
The explosion gouges a crater
115 miles wide and nearly 8 miles deep.
But many now believe that the impact alone
Wasn't powerful enough to cause their global extinction.
♪
Satellites designed to search for oil have recently confirmed
That the impact site is a part of the earth's crust
Unusually rich in hydrocarbons and sulfur.
When the meteor hits, the volatile compounds vaporize,
Creating a cocktail of climate-changing chemicals
That mix with the countless tons of melted rock.
Johnson: All that energy blows up and out.
Some of it goes out of the earth's atmosphere.
Some of it blows sideways.
Meanwhile the earth is turning,
So you have hot stuff flying out of the sky
On the other side of the planet.
♪
If you were anywhere near it, forget about it,
But if you are on the other side of the planet,
Forget about it also.
♪
Narrator: Nearly half of global plant life dies.
Half the life in the sea is snuffed out.
Three quarters of all life on the planet is made extinct.
The great dinosaurs' fate is sealed.
Although they disappear from history,
The catastrophe now creates opportunity
For others to take their place.
65 million years ago...
After the devastating meteor impact,
Over thousands of years, the world slowly recovers.
The air clears,
The fires cool,
And new forests take root.
The great dinosaurs are no more.
[sniffing]
But some life has survived.
Anjali goswami: The mass extinction that saw
The demise of the dinosaurs
Was terrible for everything on the planet quite frankly.
Mammals squeaked through that extinction.
They did not sail through it by any stretch of the imagination.
There might be as few as 20 different kinds of mammals
That made it through that extinction.
But the death of the dinosaurs
Really opened up a huge amount of opportunity for mammals,
And they took it.
They took the opportunity, and they went wild with it.
♪
Narrator: On the northern borders of india
Lie the himalayas,
The highest mountain range on earth.
Today its peaks rise five and a half miles above sea level.
♪
But by earth's standards, these mountains are young,
Less than 55 million years old.
This epic range rose in parallel with the rise of the mammals.
♪
55 million years ago, after eons of continental drift,
India smashes into eurasia.
The himalayas begin their ascent to the heavens.
♪
Recent fossil finds in india
Are adding to evidence collected worldwide
That this is an evolutionary turning point.
The precursors of many key mammalian species
Are starting to emerge and spread across the globe.
Goswami: 10 to 20 million years after the dinosaurs go extinct,
Mammals really explore the world
And develop a huge range of shapes and ecologies
That still define them today.
You start to see the first real horses.
You see whales moving into the ocean.
You start to see early primates showing up.
But it was certainly a pivotal moment in mammal history.
Narrator: For the next 50 million years,
As continents continue to shift into today's positions
And the himalayas inch upwards...
The mammals evolve.
♪
By one million years ago,
They take over the globe.
♪
And in africa, conditions are ripe
For a new chapter in the history of our world.
A new mammal will emerge,
A new type of primate that walks tall,
Who in a flicker of geological time
Will become the dominant species on the planet.
Next time, we'll explore the age of humans,
Using clues from space to provide new insights
Into why we evolved our unique human brain,
How we tamed the planet's animals and plants
To build great civilizations,
And how we develop total command of the earth's energy,
Giving us the power not only to shape our future,
But also the fate of the planet we call home.
♪