Cosmos: Possible Worlds (2020) s01e03 Episode Script

1
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)
♪♪
♪♪
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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 blood red 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 planet-wide
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
multi-cellular 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 Schönbein
was a German-Swiss chemist who
was conducting an experiment
on using electricity to reduce
water into its two
chemical constituents,
oxygen and hydrogen.
Schönbein thought he
smelled something familiar,
something like the air
after a thunderstorm.
Schönbein 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.
Schönbein loved to experiment.
So much so that his wife
famously exacted a promise
from him not to use their
kitchen as his laboratory.
♪♪
SCHÖNBEIN: Oh.
TYSON: Schönbein 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 Schönbein
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
Schönbein'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 Göttingen,
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 Göring,
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 cosmo-chemistry.
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 space faring 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 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 multi-year
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?