[distant explosions]
TYSON: We are a long way from home, and from our time.
This was our Milky Way when the galaxy was young
and more fertile than it is today.
Back then, she birthed 30 times as many stars as she does now...
a firestorm of star creation.
It's a summer night, 11 billion years ago.
We're on the planet of another star,
one with an ideal view of the Milky Way galaxy's
chaotic stellar nursery.
Our own star was a child of the galaxy's later years,
and that may be one of the reasons we exist.
After the short-lived, more massive stars died out,
there was time...
another five billion years, for those dead stars to bequeath
their heavier elements to us.
These elements enriched and nurtured the formation
of the planets and moons of our solar system.
And we ourselves are made of that star stuff.
Those blazing pink clouds of hydrogen gas are the swaddling
of countless new-born stars.
See those bright blue splashes?
They're clusters of slightly older sibling stars.
Gravity's embrace will transform this amorphous
collection of gas and dust into the galaxy we call home today.
[explosion]
Our sun is born.
The star endows her surrounding worlds
with precious minerals, diamonds and green olivine...
a mineral that will play a major role in our story.
The stars make planets, moons and comets.
There's Jupiter, the firstborn world of our solar system.
These future planets and moons are awash with organic molecules...
the chemical building blocks of life.
This is their inheritance from the deaths of other stars.
Does the cosmos give rise to life as naturally
as it makes stars and worlds?
This is our voyage to the heart of that mystery.
[theme music plays].
♪ ♪
TYSON: Long, long ago, when our world was young,
there was a city at the bottom of the sea that covered the Earth.
It took tens of thousands of years to build this city,
but there was no life on this world back then.
So who built these submarine skyscrapers?
Nature did.
She made them with carbon dioxide and the same minerals
she uses to make seashells and pearls...
calcium carbonate.
But these soaring towers were nothing compared to what
happened beneath them.
We'll need to get 1,000 times smaller to see it.
Doesn't look like much, does it?
But just wait.
Our restless Mother Earth cracked open,
and cold sea water poured down into her hot rocky mantle,
getting richer in organic molecules and minerals,
including a green jewel called olivine.
This mix of water and minerals got so hot that it
shot out of her with great force.
The mixture became trapped in the pores of the carbonate
rocks that would later become her towers.
These pores were incubators, safe places where the organic
molecules could become more concentrated.
This is how we think that the rocks built life's first home.
It was the beginning, at least in our little
part of the cosmos, of an enduring collaboration
between the minerals of earth,
the rocks and life.
See those snaky cracks?
That's how this process got its name.
Serpentinization.
It's the evidence for the conversion of water and
carbon dioxide into hydrogen and methane...
the organic molecules that fueled this earthshaking event.
Those scientists who search for life on other worlds,
they used to say, "follow the water,"
because water is the most basic requirement for life.
Now, they also say, "follow the rocks,"
because serpentinization is so closely associated with
the processes that make life possible.
To witness the main event, we have to get even smaller.
At this scale, these caves look vast,
but they're actually the tiny pores in the mortar of the towers.
These jewels are the organic molecules which are,
like everything, including you and me, made of atoms.
In order to turn these inanimate jewels into jewelry,
the stuff of life, it takes energy.
We think it happened in a treasure cave like this one.
The energy came from the reaction between the alkaline
water trapped within the towers
and the acidic water of the ocean.
That ancient treasure chest filled with rings and
bracelets and necklaces,
longer and more complex molecules,
until the greatest treasure of all...
Life.
We think it was that chemical reaction that provided
the energy that powered the first cell.
That was the spark that electrified the building blocks of life
into something alive.
Over time, the towers decayed,
making it possible for the fledgling life within them
to escape and evolve.
♪ ♪
What you've just seen is the most plausible scientific
creation myth we have today for the origin of life.
This hypothesis required the reunification
of four long separated scientific fields:
biology, chemistry, physics and geology.
We think life first took hold in the rocks.
And from day one, life was an escape artist,
always wanting to break free, to conquer new worlds.
Even the great big ocean couldn't contain it.
If that's the true story of how life got started,
it was long ago, back before the sky was blue,
before the moon spun away from us to where it is today.
Back when the planet was an ocean world,
with waters bloodred with iron.
Life would remake the world, the sea and the sky.
But life doesn't always act in its own best interest.
There came a day of reckoning,
when life nearly destroyed itself.
TYSON: The Cosmic Calendar is a way for us to wrap our
heads around the vastness of time.
To grasp the history of the cosmos,
from the birth of our universe to this very moment,
we've compressed all of it into a single calendar year.
On this scale, every month represents about a billion years.
Every day represents nearly 40 million years.
That first day of the cosmic year began with the Big Bang,
almost 14 billion years ago.
Nothing really happened in our neck of the universe
until about three billion years later...
March 15 of the cosmic year,
when our Milky Way galaxy began to form.
Six billion years after that, our star, the Sun, was born.
It was August 31st on the Cosmic Calendar.
Jupiter and the other planets, including our own,
would soon follow.
This was our planet nearly four billion years ago...
September 21st on the Cosmic Calendar,
when we believe life began.
The atmosphere was a hydrocarbon smog.
No oxygen to breathe and no one to breathe it.
We've only recently begun to appreciate how powerfully
life has shaped the planet.
When we think about the ways life has changed Earth,
the first things that come to mind are the green expanses
of forests, and the sprawling cities.
But life began transforming the planet long before there
were any such things.
A billion years after that tiny glimmer at the bottom of the sea,
life had become a global phenomenon thanks to
a champion that to this day has never been vanquished.
I give you the cyanobacteria.
In business for 2.7 billion years,
cyanobacteria can make a living anywhere.
Fresh water, salt water, hot springs, salt mines...
makes no difference, it's all home to them.
Over the next 400 million years, the cyanobacteria...
taking in carbon dioxide and giving back oxygen,
turned the sky blue.
But the cyanobacteria didn't just change the sky,
they reached into the very rocks themselves
and changed them, too.
Oxygen rusted the iron,
working its magic on the minerals.
Of the 5,000 kinds of minerals on Earth,
3,500 of them arose as a result of the oxygen made by life.
But here comes that day of reckoning.
Cyanobacteria were the dominant life-form on this planet,
wreaking havoc wherever they went,
changing the landscape, the water and the skies.
This was 2.3 billion years ago,
or late October on the Cosmic Calendar.
But the cyanobacteria shared the planet with other beings:
The anaerobes, life-forms that had come of age before
cyanobacteria had begun to pollute the Earth with oxygen.
For the anaerobes, oxygen was poison,
but the cyanobacteria wouldn't stop loading up
the atmosphere with the stuff.
For the anaerobes, and nearly all of the other
life on Earth, it was an oxygen apocalypse.
The lone survivors among the anaerobes were those
who sought refuge at the bottom of the sea,
deep in the sediment where the oxygen could not reach them.
The cyanobacteria acted like oxygen-pumping machines.
They continued in overdrive, and 400 million years later,
they brought about an even more radical change to the planet.
Remember those serpentinized rocks at the bottom of the sea
that were cranking out hydrogen and methane?
Methane is a powerful greenhouse gas,
and back then it was the main thing keeping the planet warm.
But once again, the oxygen produced by life shook things up.
It gobbled up the methane, producing carbon dioxide,
a much less potent greenhouse gas...
meaning it was not as efficient at trapping heat
in Earth's atmosphere.
Earth's temperature began to plunge.
Life, the escape artist, busted out of the icy death grip
that entombed the planet.
The corpses of dead bacteria left behind a planetwide
reservoir of carbon dioxide.
Volcanoes pumped the carbon dioxide in huge quantities into the atmosphere,
warming the planet and melting the ice.
Over the next billion years,
life and the rocks continued their elaborate dance,
taking the planet through freezes and thaws.
Then, 540 million years ago, something wondrous happened.
Life, which had been all about microbes and simple
multicellular creatures, suddenly took off in what's
called the Cambrian Explosion.
Life grew legs, eyes, gills, teeth,
and rapidly began to evolve the forms of its stunning diversity.
We don't yet know what it was that allowed life to diversify
so dramatically, but we have some plausible theories.
It could have been all those calcium minerals in
the seawater that came from the volcanoes.
Life had grown a backbone and put on a shell.
It had found a way to collaborate with the rocks
to make its own armor.
Now life could grow larger and venture forth into new territories.
Or maybe it was the protection afforded by the
canopy built by the cyanobacteria.
The oxygenation of the atmosphere created the ozone layer.
This made it possible for life to break out of the
safety of the oceans and inhabit the land without
being assaulted by the sun's deadly ultraviolet rays.
For billions of years, all life could do was ooze.
Now, life began to swim, run, jump and fly.
Life, the escape artist, had gotten so good at wriggling
out of every confine, no prison on Earth could hold it.
And there will come a day,
when life would even escape from Earth.
Life will not be contained.
♪ ♪
Retracing life's odyssey back to the very beginning
required a new kind of science,
one that reunited the disciplines.
The man who founded this new approach also happened
to be an escape artist himself.
He fled history's most implacable killers,
right here in this forest, jesting at his tormentors
every step of the way.
TYSON: Remember this place?
It's London's Royal Institution,
where Michael Faraday spent his life.
Back in his time, in the first half of the 19th century,
the intimate relationship between life and the rocks
had yet to be discovered.
Before science could tackle the origin of life,
it had to change.
This development was foretold by a scientist
whose gifts to the world, were decidedly mixed.
Christian Friedrich Schonbein was a German-Swiss chemist who
was conducting an experiment on using electricity to reduce
water into its two chemical constituents,
oxygen and hydrogen.
Schonbein thought he smelled something familiar,
something like the air after a thunderstorm.
Schonbein had discovered ozone.
Remember, that's the layer in the atmosphere that made
it possible for our distant ancestors to leave the water
for the land, and it still protects us from
ultraviolet rays to this day.
Schonbein loved to experiment.
So much so that his wife famously exacted a promise
from him not to use their kitchen as his laboratory.
♪ ♪
SCHONBEIN: Oh.
TYSON: Schonbein had just invented a new weapon of mass destruction.
A chemical explosive more powerful than gunpowder.
Upon further refinement, gun cotton would industrialize
warfare on a horrendous scale.
But it was also Schonbein who had a prophetic vision of
a new field of science.
He wrote in 1838:
"Before the mystery of the genesis of our planets
and their inorganic matter can be revealed,
a comparative science of geochemistry must be launched."
50 years later, the man who would realize
Schonbein's dream was born.
He was another German-Swiss.
Victor Goldschmidt was so brilliant,
he was offered a position here at the University of Oslo
without ever taking a test or earning a degree.
That was in 1909, when he was only 21.
Three years later, he was awarded Norway's greatest scientific prize.
Victor Goldschmidt saw the Earth as a single system.
He knew that in order to get the whole picture,
you couldn't just know physics, chemistry, or geology...
you had to know them all.
This was in the early days of the study of the basic elements.
Goldschmidt applied this new knowledge to create his own
version of the periodic table,
one that is still in use today.
It illuminated how crystals and complex minerals could
be formed from more basic elements.
Goldschmidt was discovering how matter evolves
into mountains and cliffs and canyons.
In 1928, he made a fateful decision to accept
an appointment at the University of Gottingen,
in Germany, where an institute had been built just for him.
His colleagues thought these were his happiest years, until...
[hammering]
1933,
when Adolf Hitler came to power.
Goldschmidt was Jewish, but not observant.
Hitler changed all that for him.
He now began to publicly identify himself with the
local Jewish community.
Hitler made it compulsory for everyone to list any
Jewish forbearers going back several generations.
There were those who tried to conceal a grandfather who
might land them in a concentration camp.
But Goldschmidt proudly declared on his forms that all
of his ancestors were Jewish.
Hitler and Hermann Goring, founder of the Gestapo,
were not amused.
GOLDSCHMIDT: Hmm?
TYSON: They personally sent a letter to Goldschmidt telling
him he was summarily dismissed from his university position.
He fled to Norway with only the clothes on his back.
Goldschmidt concentrated his research on olivine,
that green jewel of a mineral left over from
the formation of the solar system.
He was fascinated by its power to withstand even
the highest temperatures.
He was the first to speculate that olivine may have played
a role in setting the stage for the origin of life.
At the same time, he wondered about the presence
of olivine throughout the cosmos.
This was the beginning of a field called cosmochemistry.
In 1940, when the Germans invaded Norway,
Goldschmidt took to carrying a cyanide capsule in his pocket
so that he could kill himself instantly if the
Gestapo came for him.
When a fellow scientist asked if he could get one, too,
Goldschmidt answered:
"This poison is for chemistry professors only.
You, as a physicist, will have to use a rope."
[knock]
NAZI: Herr Goldschmidt.
TYSON: But when the Germans arrived,
Goldschmidt kept the cyanide in his pocket.
NAZI: Goldschmidt.
[speaking in German].
TYSON: He was sent to the Berg concentration camp before
they were ready to deport him to Auschwitz,
a place he told friends that "had not been highly recommended."
Goldschmidt was too important a scientist
for the Nazis to exterminate.
He was given the chance of survival if he would put
his science in the service of the Reich.
But Goldschmidt dared to toy with his captors.
He would lead the Germans on a scientific wild goose chase.
He sent them searching for nonexistent minerals
and deceived them into believing these were resources
that would be critical to the war effort.
His ruse could have been discovered at any moment,
and that would have meant certain death in the most
fiendish way possible.
By the end of 1942, the Norwegian Resistance knew
that Goldschmidt was in the gravest danger.
They arranged for him to escape across the Swedish frontier.
Goldschmidt spent the rest of the war in Sweden,
and then England, contributing his knowledge to the Allies.
Always in frail health,
he never recovered from the hardships of the war.
Victor Goldschmidt died a year and a half after it was over.
But during that period, he wrote a research paper on
the complex organic molecules that he thought might
have led to the origin of life on Earth.
And the ideas in that paper remain central in our
effort to understand how life came to be.
Goldschmidt never knew that the generations of geochemists
who came after him would consider him their founder.
Among his last wishes was a simple request.
He wanted to be cremated and
to have his ashes encased in an urn...
made of the thing he believed to be the stuff of life,
his beloved olivine.
The universe makes galaxies.
Galaxies make stars.
Stars make worlds.
Are there other Lost Cities of Life in the cosmos?
Come with me.
TYSON: There are dues to be paid for cosmic citizenship.
As a spacefaring species, you have to worry about
contaminating the worlds you visit and about bringing
back alien stowaways that might pose a danger to your home world.
There are protocols for planetary protection.
NASA designates five categories of worlds in the cosmos.
Earth's moon, for instance, is a Category-1 world...
a place so lifeless, we pose no threat to it,
and it poses no threat to us.
The riskiest mission of all is a Restricted Category-5 world,
like this one, Mars.
The conditions for indigenous life...
in the past, or even now, hidden in some subsurface recess,
are not beyond possible.
We have to be very careful,
for our own sake and for the life that could conceivably be there.
The Restricted Cat-5 designation is a recognition
of life's genius for escape.
It applies to sample return missions from those worlds
where life may have gotten started...
those worlds that may have, or once may have had,
Lost Cities of Life lying at the bottom of their seas.
But in a sense, our robot emissaries themselves...
our landers, rovers and orbiters,
are a manifestation of life's relentless imperative
to seek out and take new territory, and this means that some of
our emissaries have to be destroyed as soon as their missions are over.
Like, poor Juno.
After a multiyear reconnaissance of Jupiter,
NASA is sending her to her death.
Not because they were worried about Jupiter.
There's hardly any chance that one of our spacecraft
could compromise future investigations of the giant gas planet.
Any rogue microbe would catch a downdraft and sink where
it would be broiled by the scathing temperatures.
That's why Jupiter's only a Category-2 world.
But one of Jupiter's moons is a Restricted Cat-5,
and NASA can't take the chance that Juno might
inadvertently crash into it.
Europa is another one of only three Restricted Cat-5 worlds
in the solar system, and one of Jupiter's 80
and still counting, moons.
Michael Faraday discovered Earth's magnetic field,
and there's one around Jupiter, too.
We can see it if we switch from looking at Jupiter in
visible light to looking at it in radio waves.
Jupiter's magnetic field is much stronger and 18,000 times bigger.
It's a gigantic trap for charged particles that are the solar wind.
That's one of the things that lights up the aurora,
the northern and southern Lights on Jupiter,
and it does the same thing on Earth.
Imagine what it's like for little Europa and her sister
moons to live so close to the king of the Planets.
Massive Jupiter holds Europa to him in a gravitational
embrace so powerful that in four billion years,
she has never been able to turn her face away from his.
Jupiter's hold on her is so fierce that it tears her skin apart.
See those broad scars?
Watch them closely and listen.
[colliding rocks]
That's the sound of a world being gravitationally tormented.
It's called tidal flexing, and it's not just Jupiter,
her sister moons pull on her, too.
We are half a billion miles from the sun's warmth,
five times farther away than Earth is,
but this tidal flexing keeps Europa toasty inside.
Beneath her chaotic surface, there's an ocean ten times
deeper than the deepest seas on Earth.
♪ ♪
We're on our way to another Restricted Cat-5 world.
No, not Saturn.
Saturn's another Cat-2.
Any life passing through those cloud belts wouldn't have a chance.
They're made mostly of ammonia.
Below them are bands of water vapor.
In one of our future voyages, we'll go there at a terrible cost.
It's not Titan, either.
Titan's another Category-2 world.
Just as with Saturn, the possibility of us interfering
with the life that might be there is too remote.
Of course, there's always the chance that Titan life
is stranger than our ability to imagine.
Even if that's the case, there is little likelihood
that any form of Earth life could harm it.
There she is, our Restricted Cat-5 world.
TYSON: There's a world in our solar system that may harbor life.
You're looking at two of the first people ever to see it.
William Herschel saw farther into the deep waters
of the cosmic ocean than anyone before him.
His son, John, would also become a distinguished astronomer.
But tonight is back when John was a child in the summer of 1802.
That's when we first met them on an earlier voyage.
WILLIAM: John, I want to show you something.
Come with me.
TYSON: This was then the largest telescope on Earth
and would be for 50 years.
CAROLINE: Well, what have we here? Hmm?
Isn't it awfully late for a little boy to be up?
JOHN: Father has promised to show me something, Aunt Caroline.
TYSON: William's sister, Caroline Herschel,
was a world-renowned astronomer in her own right.
She was the first woman anywhere on Earth to be paid
for being a scientist.
She was just four-foot-three.
When Caroline was ten years old,
she was stricken with typhus.
She lost part of the vision in her left eye and stopped growing.
And yet, she defied the limitations of her time to a point.
Caroline had just published her work in the
"Catalogue of Nebulae and Clusters of Stars,"
but it was under her brother William's name.
It was 1802, after all.
Her nephew, John, would grow up to build on her
work and create the "New General Catalogue."
Many astronomical bodies are still designated by their NGC number today.
WILLIAM: A few more degrees east and a degree north.
ASSISTANT: Yes, sir.
WILLIAM: Stop, stop! There she is.
JOHN: Father! I've never seen that before.
Is it a new star?
WILLIAM: No, son, it's a new moon.
I call it Saturn Two.
JOHN: Oh, but Father, we must think of a better name than that.
WILLIAM: That's your job, my boy.
TYSON: And John would do exactly as his father asked.
He named the moon Enceladus, after the Giant in Greek
mythology who was the son of the Earth and the Sky.
Enceladus fought the goddess Athena in an epic struggle
for control of the universe.
You don't have to be an astrobiologist to know at
first glance that life is everywhere on Earth.
It's changed virtually every square inch of the place.
From an alien point of view, Earth would certainly have a
Restricted Cat-5 status.
But Enceladus keeps its secrets hidden deep inside.
♪ ♪
Those geysers of ice and water vapor are shooting out
of Enceladus at 800 miles per hour.
They're this moon's contribution to the outermost so-called "E" ring of Saturn.
But there's a lot more in them...
nitrogen, ammonia, methane.
And where there's methane, there may be olivine.
Enceladus has been at this for at least 100 million years.
It could keep cranking out water for another nine billion years.
Where's all that water coming from?
The blue snowflakes plummet at more than 1,000 miles per hour.
We've come here to the southern hemisphere because
that's where the ice crust is thinnest.
It's only a couple of miles thick.
That's why it's the best possible place to gain access
to the underground ocean.
Okay, now's the time for a warning:
What you see here is entirely based on evidence.
That global ocean, the crazy curtain of geysers,
that weird snow at the surface...
it's all real.
We have multiple observations from the Cassini
mission telling us that this is what awaits us on Enceladus.
But we're about to enter the realm of informed speculation.
This is what the leading space scientists think we might find
when we send a spacecraft to dive straight into the heart of Enceladus.
[geyser erupting]
When water up here is exposed to the vacuum of space,
it turns to snow.
And that scum is the stuff of life...
organic molecules.
It makes you wonder what could be waiting for us down below.
And that's a long way from here,
because we're in an ocean that's about ten times deeper
than the oceans of Earth.
Very promising.
That's carbon and hydrogen, and the pH of the water is
just like the early ocean on Earth.
♪ ♪
Why would this City of Life be larger than the one at the
bottom of the ocean on Earth?
Maybe it's because the gravity on Enceladus is so
much weaker than it is on Earth.
With less gravity, the towers are lighter,
and they can grow taller.
The currents are strong,
and they may have toppled some of the towers.
Victor Goldschmidt's olivine.
The rocks have made a place for life.
But has life had enough time to take hold?
All I know is, never underestimate the escape artist.
You know, it's a funny thing about us.
We think we're the story.
We're the end all and be all of the cosmos.
And yet, for all we know, we're just the by-product of
geochemical forces...
ones that are unfolding throughout the universe.
Galaxies make stars, stars make worlds,
and for all we know, planets and moons make life.
Does that make life less wondrous?
Or more?
Captioned by Cotter Captioning Services.