[music playing] NARRATOR: This is the
epic story of our world. But it's not the
one we're used to. It's the story of how
we almost didn't happen. [music playing] We turned back time
4.5 billion years to our solar system still
forming around the sun. This planet is early Earth. It's at a critical
distance from the Sun. [music playing] It is in this zone that liquid
water will be able to exist. Any closer, and our
future cities would burn and our oceans boil. Any further out, and
our future freezes over. Earth's location is just
one of many lucky breaks. The next comes in the
form of cosmic disaster. [music playing] A massive object the size of
Mars collides into early Earth. [loud rumbling] If the collision were
head on, our planet would have shattered. Instead, the debris
forms our moon. The Moon is a counterbalance
stabilizing Earth's rotation, which will prevent
catastrophic swings in climate. Another lucky break. [music playing] As Earth cools,
the heaviest metals sink and form a spinning core. [roaring] Sending a giant
invisible force field around the planet, a magnetic
field that will one day protect us from deadly radiation,
and keep our atmosphere from blowing away. [music playing] But since most heavy
metals sank to the core, Earth's surface is devoid of the
vital materials, the iron, tin, lead, and gold that
we will one day need. [clinking] [music playing] That is until Jupiter and
Saturn step in to help. Millions of miles away,
these massive planets shift in their orbits
sending billions of metal rich asteroids
through space showering earth and replenishing our supply. [music playing] [crashing] Then, another lucky break. [music playing] Jupiter's orbit stabilizes
and its masses gravity begins to vacuum up most of
the remaining rocks keeping our future home safe. Without a giant
neighbor like Jupiter, Earth would still be under
constant asteroid attack. [music playing] If just a single
one of these things had not happened in
precisely the right way, our story would unfold
differently, or not begin at all. [music playing] Earth would not have
the minerals and metals, the stability, the seasons
to support the amazing saga that is to come. In this special
presentation, we'll see that everything
is connected. You can't look at this as
a tiny little remote events, that these are huge coupled
aspects events that themselves are part of a larger history. They are big history. [music playing] NARRATOR: We think of history as
a timeline, a series of events stretching a few thousand
years into the past. It's time to think bigger. Instead of a lie, imagine a
web of infinite connections interacting over billions
of years, linked together to create everything
we've ever known, our universe, our
planet, and us. History as we know it
is about to get big. [music playing] CRAIG BENJAMIN: Big
History takes events all over the cosmos, all
over the solar system, all over our planet, and
connects them together into a seamless whole, and
then connects those events in human history
into the context of the planet, the solar
system, and the universe. NARRATOR: The story we just
saw, the series of lucky breaks that led to the
formation of the Earth, is what Big History
calls a threshold moment. [music playing] DAVID CHRISTIAN: The
idea is basically that the early universe
in all sorts ways was really quite simple. No stars, no life, no planets. And then, gradually
over 13 billion years, new things appeared. And that idea provides a great
shape and structure and a sort of plotline. We focus on a number of
moments when something critical appeared. And that's what we mean
by threshold moments. [music playing] NARRATOR: In the
story of big history, there are a total of
eight threshold moments. Moments when the
universe crosses a line and can never turn back. [music playing] The creation of the Earth
is the fourth threshold. We'll reveal them all and
uncover the surprising secret that links them together. [swishing, bubbling] But to do that,
we have to go back to the beginning, the
first threshold moment nearly 14 billion years ago. A moment that had only a split
second to unfold precisely as it did or the entire universe
might have ended shortly after it began. [music playing] It is the quietest quiet
there has ever been. And then, suddenly, out of
nothing, everything begins. [large explosion] It is big history's first
threshold, the Big Bang. [music playing] In a fraction of a second, all
the energy that will ever exist appears in an
inconceivable flash. [music playing] CRAIG BENJAMIN:
Everything begins as far as you know at this moment. And from the moment
it appears, physicists can offer a very coherent
account of everything that happens since. [rumbling] NARRATOR: Before the
first second has passed, the fundamental forces appear
that will govern all existence forever. One is the gravity that
holds us to the Earth, and that we will need to
overcome in order to fly. Another, the electromagnetism
that lets you make a cell phone call. [beeping] JONATHAN MARKLEY: The Big
Bang is the creation event that lays the ground rules. It lays the ground rules
of the fundamental forces, the strength of gravity,
the speed of light, all of the things that will
shape the rest of the history of the universe. [music playing] NARRATOR: And in these
first few seconds, a lot could have gone wrong. If gravity had been just a tiny
bit stronger, all of existence would have collapsed
in on itself. [fizzling] A bit weaker, and stars
would never be able to form. [music playing] But the Big Bang occurred
at just the right force to set our entire history
in motion, which is why it's the first of eight thresholds. We will see that they are
all mysteriously connected. Eight thresholds that
explain everything. Eight portals that lead to
us, including the next one, the moment when the immense
heat, darkness, and chaos of the early universe suddenly
explodes into a trillion trillion points of light. [music playing] Big History has begun to reveal
the eight biggest turning points in the story
of our universe. Eight threshold moments that
will mysteriously lead to us. [hartbeating] The first, the Big Bang. [music playing] [explosion] Exploding in just the right way
to create forces like gravity, but it's still too
hot to form atoms. [music playing] All of that is about to change. We are about to reveal the
second threshold moment. JONATHAN MARKLEY: Only at the
point of about 380,000 years have things cooled enough
that we can finally get matter as we recognize it. ALEX FILIPPENKO: Without
a cooling universe, there is no way that we
are anything else that has real structure would exist. NARRATOR: The first
atoms to appear are hydrogen and helium,
the two most basic elements. But their formation is
not the second threshold. Hydrogen and helium are just the
building blocks of the portal yet have to come. Since all matter exerts
a gravitational pull, giant clouds of these atoms
begin to clump together into forms we recognize today. ALEX FILIPPENKO: Gravity is
the sculpture of the universe, and small variations in
the density of the universe at early times led
to the formation of these gigantic structures,
galaxies and clusters of galaxies, and superclusters
of galaxies separated by enormous voids. This is mega engineering
on the largest scales. NARRATOR: Now, within
these mega structures, trillions of smaller clouds
of hydrogen and helium begin to condense and spin. CRAIG BENJAMIN: So gravity
is working on these clouds, crushing, condensing,
compressing. Inside them temperatures
are increasing. Pressure is heating up. And eventually once
a certain temperature is reached inside these
vast clouds, roughly 10 million degrees Celsius,
nuclear fusion will take place. NARRATOR: Once these
conditions are met, and the critical amount
of atoms, temperature, and pressure come together, we
reach another turning point, big history's second
great threshold-- [music playing] Stars light up. [music playing] JONATHAN MARKLEY: There was no
light immediately before this, because there was nothing in
the universe to create light. And we hit a very
significant threshold in the history of the universe. Let there be light. NARRATOR: From
this point onward, the universe crosses through
a portal from which there will be no turning back. Before stars, all the
energy in the universe emanated from one
source, the Big Bang. Now, there are sites scattered
throughout the universe, hot spots of energy,
warmth, density. [music playing] The first generation of
stars light up the universe. But their fuel
begins to run low. They start to burn out. [music playing] It is with the death of this
first generation of stars that we cross another
portal in our epic story, big history's third great
threshold, the creation of complex elements. [music playing] Within the dying cause
of stars, simple elements fuse into larger and
more complex atoms. For the first time,
hydrogen and helium create brand new elements that
will make the modern universe possible. [rumbling] CRAIG BENJAMIN: As stars
begin to run out of hydrogen, they heat to higher and
higher temperatures. They start converting helium
to more complex elements, and this whole process continues
right up the periodic table. NARRATOR: As it dies, each
star becomes an element factory creating just the
right conditions to form the elements. And once they're
formed, the universe will never be the same. ALEX FILIPPENKO: A
star uses the ashes of one set of nuclear reactions
as the fuel for the next set. Hydrogen to helium,
helium to carbon and oxygen, carbon and oxygen
to neon and magnesium, then silicon and sulfur,
and then iron. [music playing] NARRATOR: So more than 12
billion years ago, stars are creating the element that
will make possible everything from the Iron Age
to the ironclads. [music playing] But these dying stars
don't have enough energy to create anything heavier
than iron until they explode as supernovas. [explosion] The biggest blasts
since the Big Bang. [explosion] The intense heat and pressure
produces elements heavier than iron. But even these
mega blasts are not enough to create the
heaviest elements, like the gold that will draw
Europeans across the Atlantic, and cause millions to
flood into California. For that, you need
the biggest blast of all, the collision between
the ruins of two supernovas known as neutron stars. [explosion] These new elements
billow out into space, forming new clouds
that come together in new second generation stars. Each time the process repeats,
more elements are created. JONATHAN MARKLEY: As you head
further up that periodic table, you are basically seeing
the order of creation, and the difficulty of creation,
and how much energy is required to create them. [explosion] NARRATOR: Some elements
will be abundant. Others rare. Their proportions will
have profound effects on all of history to come. For example, there is
more silver in the universe than there is gold, because
it requires more energy and is more rare to get those
events where gold can be created. [music playing] NARRATOR: But that is all
waiting for a distant future. It will take eons before
dying stars create enough of the raw materials, like iron,
nickel, and calcium, to form rocky planets, like Earth. So during the first few
generations of stars, Earth-like planets can't
exist, and neither can life. [music playing] But billions of years after the
Big Bang, a newer generation of stars appears,
including our sun. This time, there are enough new
minerals and metals to create rocky planets as well. JONATHAN MARKLEY: It is truly
mind blowing when you realize that the elements that
are present on our earth and in our sun, cannot exist
unless there has been at least two generations of star systems
before us that have lived and died. Can you imagine the
elements in our body, have to have been through
this event twice before, before you can get
a creature like us. [music playing] NARRATOR: Early thresholds
reveal that the first atoms in the universe are reincarnated
throughout billions of years from one element to another,
from star to exploding star, from isolated early atoms to the
elements that form everything around us. Some of the atoms in our bodies
are more than 13 billion years old. [music playing] These are the building
blocks that will lead us to the next threshold and the
most mysterious turning point in the big history of the
universe, the one that will finally lead to us. [music playing] Big History is a new story of
mankind that traces our origins through eight pivotal moments. [music playing] The first three, the Big
Bang, the birth of stars, the creation of
complex elements, transform everything
in the universe, and lead us to the
fourth monumental turning point in our big history,
the formation of Earth. [music playing] This is our galaxy, more than
4 and 1/2 billion years ago. An ancient star
collapses and explodes. [explosion] Launching a massive
shockwave into a nearby cloud of gas and dust, its force
causes the cloud to spin. Gravity crushes and compresses
it, sculpting the cloud and heating it up
to 10,000 degrees. And from the remains
of an ancient star, a new one bursts into light. Our sun Illuminates eight young
planets forming around it. As we've seen, a series
of improbable events now line up to push us
across the fourth threshold. [music playing] Like pieces of a grand and
infinite puzzle leading to an earth capable
of sustaining life. [music playing] First, a massive collision. [explosion] GREG LAUGHLIN: It created
a huge molten disk of rock around the Earth, which rapidly
coalesced to form the moon. NARRATOR: By a stroke
of luck, our moon is one of the largest
in the solar system, so its gravity is
powerful enough to affect how the Earth behaves,
giving us a steady climate and predictable seasons. If it hadn't been for
the presence of the moon, Earth's axis of rotation would
undergo chaotic giant changes in tilt, and this would lead
to huge disruptions in climate, and it's unlikely that
advanced complex creatures, such as ourselves,
could have evolved. [music playing] [explosion] NARRATOR: But even with the
stability created by the Moon, this young planet isn't
ready to become a home. Big History can't move to the
next threshold without water, and most of it was just blown
away by the heat of the moon forming impact. [music playing] But the chaotic early solar
system comes to the rescue. ALEX FILIPPENKO:
Meteroids and asteroids rich in water come
from the outer parts of the asteroid belt, and are
thought to have brought a lot of the water to the Earth. [explosion] DAVID CHRISTIAN:
You turn on a tap, and you may well be drinking
stuff that was delivered to you personally by
an asteroid about 4 and 1/2 billion years ago. [music playing] NARRATOR: And now, deep
in the ocean waters carried to Earth by
comets and asteroids, we are about to witness the
fifth and most mysterious of the big history
thresholds, life. [music playing] How exactly does life emerge? It's one of our most
profound questions. Some believe that life may
have crash landed on Earth in meteors or comets. But most believe
that life on Earth starts with a chemical
reaction down in the deepest depths of the ocean where heat
rising from the planet's molten core tears apart the sea floor. Superheated gas and lava
vent through the cracks and ignite a revolution. [music playing] In this broiling soup,
a new kind of chemistry emerges, a biological blueprint
for every living thing that will ever exist. A secret code called DNA. Just four chemicals will
combine in millions of ways to instruct every cell
on how to do everything. [music playing] Beginning with bacteria,
the simplest and oldest form of life. CRAIG BENJAMIN: Here's where
early forms of bacteria appear feeding off the energy
in the heat that was coming out of these volcanic eruptions. Here, we think the
first life on Earth appeared beside these great
undersea mountain ranges. [music playing] NARRATOR: Life is the only
thing in the universe that can store and pass along
information, reproduce itself, and evolve. But how does a simple
microscopic organism evolve into something
as complex as a human? The path from bacteria to
man is a mysterious series of transformations
with an infinite number of possible outcomes, but
only one that leads to us. The seeds of everything that
will happen on the future Earth are all descended from
these simple beginnings. [music playing] Earth, 542 million years ago,
three billion years after life first appears. In a geological
instant, the seas explode with complex
plants and animals. All the basic body types
that will ever exist, heads, mouths, eyes, fins that
will evolve into limbs, jaws and teeth, all of
them suddenly appear. [music playing] 475 million years
ago, plants begin to spread across the land
transforming the earth into a world of lush forests
with abundant food and shelter. [music playing] Some plants evolved into
trees, that along with metals brought by meteors, will
become key building blocks of civilization. [music playing] To escape the
carnage in the seas, some creatures crawl
onto land as well. [growls] At first, they're forced
to return to the salty seas to reproduce. But then, they discover a way
to bring a bit of the ocean with them, the egg. [music playing] When we started
crawling onto the land, certain creatures figured
out-- birds, reptiles-- that they could lay eggs that
have a nice hard shell that kind of keeps the
salt water contained in a small space for them. [music playing] NARRATOR: The egg is a
critical development. It allows animals to move
permanently onto land. Animals that will continue to
evolve and grow more complex. [music playing] But now, Big History reveals
a fundamental secret that governs all life on the planet. The more complex you are,
the more fragile you become. Some simple bacteria can survive
being frozen, boiled, crushed, or dried out. Complicated animals,
like us, cannot. So when the earth is shaken by
a drastic change in climate, or volcanoes poison the air,
or a giant meteor strikes, life faces the ultimate
threat, extinction. [explosion] [music playing] Five times since complex
animals appear, more than 50% of all life is wiped away. [rumbling] But these catastrophes clean
the slate for new creatures to evolve and fill the void. Without them, Big
History's future thresholds could never occur. [music playing] TREVOR VALLE: A
good way to put it, is that every extinction
does reshuffle the deck. You just take all of
the playing cards, put them back, mix it up,
and deal yourself a new hand. [music playing] [chirping and growling] NARRATOR: One
catastrophic reshuffling ends the 165 million year
reign of the dinosaurs, when a huge asteroid plunges
into Earth 65 million years ago. [rumbling] [explosion] [music playing] DAVID CHRISTIAN:
Temperatures plunge. Plants don't grow. NARRATOR: A great era
in Earth's history has come to a fiery end-- [music playing] [birds chirping] Clearing the way for the age
of mammals, the age of us. [music playing] But what most people don't
know, is that it almost didn't happen. [music playing] Big History reveals how a
series of rare and unlikely connections across
three billion years make Earth a thriving planet. But what does it take for
the planet to make us? And what exactly does
it mean to be human? [rumbling] It all starts with a lucky
break that kills the dinosaurs-- [explosion] And clears the way for the
ultimate rise of mankind. [music playing] With the dinosaurs
gone, tiny mammals begin to take their place. CRAIG BENJAMIN: Humans
are ultimately evolved, descended from these mammals. If there had been no asteroid
collision 65 million years ago, would the human
species even exist? Probably not. [chittering, music playing] NARRATOR: But as we've seen
with so much big history, things could have
been very different. [music playing] DAVID CHRISTIAN: If
that asteroid had been on a trajectory five minutes
earlier or five minutes later, it would have missed the
Earth, and the dinosaurs would probably still rule the Earth. [growling, squawking] NARRATOR: Instead, life
begins a new chapter. [music playing] 50 million years ago, the
spread of a new plant, grass, draws mammals out of the forest. Over the next 45 million
years, the ancestors of horses grow larger,
stronger, and faster. [whinnies] Sheep, goats, and aurochs,
the ancestors of cows, evolve. [mooing] [music playing] Mankind will use them
for food and power to build civilizations. [music playing] But first, on the
savannas of Africa, more than four million
years ago, some primates take the first steps
toward becoming human. [music playing] TREVOR VALLE: We left the trees
and the grass was really tall. We had to see over it. And walking on our
hind feet allowed us to hold babies
and tools, and hunt, and free up our hands
and our opposable thumbs. [music playing] NARRATOR: Since we no longer
need to walk using our knuckles or swing from trees,
our shoulders and wrists evolved to do something
unique in nature, throw accurately,
making it easier to hunt and kill for meat. [music playing] JONATHAN MARKLEY: Look
at that natural world. How do you kill something? Almost always, you kill
something by getting up close and personal. You do it with your claws. You do it with your teeth. Now, look at your claws. Look at your teeth. Do you really want to
get up close and personal and try to kill something
with these pathetic teeth? These pathetic claws? I don't think so. [music playing, men yelling] This change in our arms
leads to an arms race that will define human history. [gunfire, men grunting] JOHN SHEA: We can cause
death at a distance in ways that no other species can. [music playing] There are thousands of species
on Earth that eat meat, but only one that cooks it. [music playing] Early man uses fire and tools
to make meat easier to digest. A behavior that
changes our biology. DAVID CHRISTIAN:
If you eat meat, you get highly
concentrated energy, but it's hard to
digest and chew. Now, if you cook it, that's
like pre-digesting it. That would mean that
the gut can get smaller. If the gut gets
smaller, there's energy available for another organ
to grow, such as the brain. So this may be a very neat
explanation for the very rapid growth in brains. [music playing] NARRATOR: The human brain
is not the largest on Earth, but pound for pound,
it's the most powerful. Able to process one quadrillion
pieces of information in a lifetime, more than
any other living creature. [music playing] So life on the African
Savannah transforms our bodies and our brains, and
its legacy is still imprinted in our minds. [music playing] In need of water, we constantly
search for the shiny sparkle of sunlight on
rivers and streams. [music playing] One reason why today we are
attracted to shiny substances like gold. [music playing] After 350,000 years of
evolution in Africa, our ancestors have
separated themselves from every other
species on Earth. We have crossed a threshold
that makes us uniquely human. But what is it? What sets us apart? It's the key that unlocks the
sixth big history threshold, and it begins when
one person makes a discovery, like a
new way to kindle fire, or a new kind of tool, and
shares it with his clan. The idea spreads
through the population, then across generations. Humans begin to build a
database of knowledge, built on millennia of
shared experience. What starts with changes like
cooking meat and growing larger brains, propels us across
the next great threshold in big history, a threshold
as important for humanity, as the formation of Earth,
or the birth of life. Big History calls it,
collective learning. [music playing] DAVID CHRISTIAN: Here, now,
we have the first species in the history of our
planet in which information can accumulate from
generation to generation. And that, I think, tells
us everything about what makes humans different. [music playing] NARRATOR: 60,000 years ago, the
planet has molded our ancestors into modern humans with
brains and skeletons identical to our own. Collective learning has
given us the tools and skills we need to dominate the planet. [music playing] But despite all our
advances, the human story could have ended here
isolated in Africa. Species that are confined
to only one continent can easily go extinct. [music playing] But Big History reveals
how the Earth shifts in a way that will spread
man and all the things he's learning all around the planet. [music playing] The Ice Age lowers the sea
level between Africa and Arabia creating a gateway to an
otherwise unpopulated world. A tiny group, perhaps
just a few hundred, get on a handful of rafts and
cross these narrow straits. This African exodus
only happens once. [music playing] In the future, all
humans outside Africa will be descended from
this one tiny clan. [rumbling] [music playing] In these new lands, the Ice
Age will test the limits of collective human learning. Faced with extreme
cold, people innovate. They cover themselves in a new
invention, head to toe clothes, tailored with
needles and thread. Their dark skin gets
almost no direct sunlight, which is critical in
creating vitamin D. JOHN SHEA: One way
of dealing with that, was to evolve lighter
skin that didn't block the rays of the sun as much. [music playing] NARRATOR: This change
begins to create the fundamental divisions
we think of today as race. [music playing] Instead of being
slowed by the Ice Age, humans adapt and spread. One group makes it to Siberia
and crosses a bridge of land to North America. [music playing] 10,000 BC, glaciers
start to melt. Seas rise. The bridge to
Siberia is submerged. The Americas are cut off. DAVID CHRISTIAN: Suddenly,
water enters the Bering Straits, so populations now get sort
of locked in to the regions they've migrated to. [music playing] NARRATOR: From now on,
for thousands of years, it will be as if humanity
lives on different planets. But that separation
will ultimately prove our similarities
as humans everywhere do remarkably similar things,
launch empires, build pyramids, master new technologies,
cross new thresholds, and begin big history's fateful
march to the modern world. [music playing] Big History reveals how
collective learning, threshold number six in big history,
gives man the tools we need to survive the Ice Age. [music playing] Now, as the glaciers
retreat, the very success that allows humanity to
spread to the farthest reaches of the planet
might also be our downfall. There's too many
people on planet Earth, and not enough food. The solution is the seventh
threshold of big history. It might be hard to imagine
how it fits in with such epic events as the Big Bang
and the origins of life, but for mankind, it
will change everything. A true turning point that
revolutionizes how we live. For the first time, we stop
moving and settle down. It's a step toward building
the civilizations that will dominate the entire planet. Threshold number seven,
the farming revolution. [music playing] CRAIG BENJAMIN: This is arguably
the most important revolution in all of human
history, perhaps even in the history of our planet. [music playing] NARRATOR: Beginning
10,000 years ago, the change over from hunting
and gathering food to farming is a triumph of
collective learning. We seized control of evolution
by breeding wild grasses into our most important foods,
like corn, wheat, barley, and rice. DAVID CHRISTIAN: Of course, they
didn't understand about genes. They didn't
understand the science of what they were doing. But once humans start
really concentrating on a particular species
and looking after it, then you can find very quickly,
within just a few generations, the species itself
starts changing. NARRATOR: The natural world
becomes our laboratory. [music playing] Wild beasts are no longer just
enemies to be feared or hunted. They are creatures to be
tamed and bred, turned into vital allies. We domesticate wild wolves
into dogs, wild pheasants into chickens, wild boars
into pigs, the fierce aurochs into the modern cow. [mooing] All modern cows, more
than one billion animals, 250 different breeds, providing
all of the 130 billion pounds of beef that we eat every year
descend from a herd of just 80 aurochs that our ancestors
domesticate 10,000 years ago. [grunting] [music playing] This revolution also gives us
our most powerful animal ally, the horse. [whinnying] Which, today, has a huge
and surprising impact on how we speak. The horse is first tamed
by Asian tribes that speak an ancient language
called Proto-Indo-European. With this radical new
way of getting around, they fan out, spreading
their language far and wide. Over time, it branches into
hundreds of languages spoken by almost half the world. [music playing] CRAIG BENJAMIN: We wouldn't
be having this conversation, at least not in
English, if it was not for the role of the horse in
spreading language, culture, and humans. [music playing] NARRATOR: The farming revolution
also depends on chemistry and the superpower of salt. [music playing] To survive as a farmer, the
food you harvest in the fall has to last all year. Salt pulls moisture out of
food which kills off microbes and keeps it from rotting. JONATHAN MARKLEY: One
of the great problems for agricultural societies
is how to preserve things, and salt is the answer. [music playing] NARRATOR: Preservation turns
farming from a lifestyle change into a revolution. [music playing] For thousands of years,
the only jobs that existed involve hunting
or gathering food. Now, with the ability to store
food and build up a stockpile for the future, for the
first time in history, people can devote their
energy to something more than survival. It is the beginning of
mankind's first job market. [music playing] DAVID CHRISTIAN: You start
getting a division of labor. Some people specialize as
soldiers, some as priests, some as metal workers, and
eventually, some as rulers. [music playing] NARRATOR: And what makes the
farming revolution even more momentous, is that
by planting seeds, we begin to put down
roots causing much more than just food to grow. Villages become towns. Towns become cities. And cities become civilizations,
ushering in an age of all powerful rulers. [MUSIC PLAYING WITH PEOPLE
CHANTING] One of those rulers, an Akkadian
king called Sargon the Great raises a huge army,
conquers his neighbors, and create something
entirely new where one King rules over many
different cities and peoples. It is the world's first empire. It's a pattern we see
across the ancient world. Where cities rise,
empires follow. [music playing] CRAIG BENJAMIN: This impetus
to construct empires appears to get deeply embedded in
the cultural DNA of all these civilizations. [music playing] NARRATOR: Empires
depend on loyalty from thousands of subjects
over vast territories. So early rulers build giant
mega structures to signal they're all inspiring power. Thousands of common
laborers piled giant stones into enormous artificial
mountains, ancient pyramids that rise around the
world, a pattern that links human civilizations
across the globe. [music playing] As civilizations
grow and connect, our wealth of
collective learning expands, and we soon need a way
to record and share knowledge. JOHN SHEA: All of the
world's major civilizations at some point confronted
the problem of there being too much information
to keep it in your head that they had to develop
permanent ways of recording information. NARRATOR: So we begin making
marks on clay, stone, papyrus, and bamboo to help
us remember things. Writing is a
breakthrough that allows us to pass on our experiences
directly to future generations. [music playing] From writing, to
pyramids, to the rise of the modern metropolis,
everything we call civilization can trace its origins back
to the farming revolution, a big history threshold that
transforms the way we live. [music playing] But although common
human traits unite us, the natural world of
climate and geography will divide us, and plunge the
world into an epic clash that threatens to bring entire
civilizations crashing down. [music playing] Big History is an epic new
way to look at the world. Connecting the traditional
history of empires and civilizations to the
geology of mountain ranges, the evolution of animals, even
the Earth's tilt and climate. [music playing] Cities and civilizations take
hold in warmer climates, places where it's easier to grow food. [music playing] In the north, where it's
too cold for most crops, grass is one of the few
plants that can survive. Herd animals thrive on it. So people here saddle up
instead of settling down, and become expert
herders and raiders. [whinnying] [music playing] JONATHAN MARKLEY: Horse based
warrior cultures are going to be the optimal
mode of existence. [music playing] NARRATOR: So climate
divides the old world, and gives us
different destinies. Where it's warm, permanent,
prosperous settlements built on farming. Where it's colder, roving bands
of nomads, who sometimes loot and pillage richness
from the south, and even bring entire
civilizations crashing down. [music playing] From the tribes that swarm
over China's Great Wall, to the Huns, Goths, and Vandals
who destroy the Roman Empire, to the Mongols who conquer
most of the known world, it's an epic conflict
that lasts 5,000 years. [music playing] But climate is not the only
force with a profound impact on big history. Geology, the shape and
movement of continents, and the location of
formidable mountain barriers plays a vital role. [music playing] In Europe and
Asia, civilizations grow faster and more massively
than their counterparts in the Americas. So what does the old world have
that the new world doesn't? The Earth reveals that in
the eastern hemisphere, plate tectonics aligns the
land from east to west, and a single mountain
system, the Alpide Belt stretches across two continents
from the Alps to the Himalayas and beyond. [music playing] Because the old world
and its mountains are oriented from east to
west, people can migrate easily alongside them for
thousands of miles, bringing their crops,
animals, and ideas. JONATHAN MARKLEY:
Human migration tends to run east-west,
because the length of the days remains, the same the
temperature tends to remain about the same, the rainfall
tends to be pretty consistent. That means that whatever you
were growing in one place will probably transfer. [music playing] NARRATOR: Here, the busiest
land trade routes in history carry new technology from
one place to another, connecting everyone
in a vast web that enriches civilizations
from China to Europe. [music playing] On the other side of the
world, the American continents are oriented in a
north-south direction. So crops grown in North
America rarely survive in the different
climates of the south. And north America's
great mountain systems, the Appalachians in the east,
and the Rockies and Sierras in the west, split the continent
with north-south barriers that obstruct migration and trade. [music playing] By looking to
geology, big history reveals why it's harder for
civilizations in the Americas to exchange ideas. But there's another obstacle
that sets the new world apart from the old. There are no large
animals to domesticate for food or transportation. A small thing, like
the lack of horses, can have a big impact
on civilization. DAVID CHRISTIAN:
Most transportation is still by human porters. That may have limited
the possibilities for commerce, trade, and
exchange in those areas. CHARLES MANN: On a horse,
you can get from point A to point B, and they're hundreds
miles apart, relatively easily. It's not a huge deal. For people running, that's
a very very big deal. [music playing] NARRATOR: So by connecting
traditional history to science, big history reveals why new
world empires lag behind those across the Atlantic in
size and technology. [music playing] The old world in alignment
of continents and mountains, and access to animals,
like horses and camels, create conditions
that are just right. They link us across
thousands of miles, like synapses in a
vast interconnected brain of human knowledge. Amplifying the uniquely
human skill of accumulating and sharing information,
the big history threshold called collective learning. So an idea that starts in
one small part of the globe has the chance to
change the world. [music playing] Some new ideas can be explosive. 850 AD, the Chinese unlocked
the chemistry of gunpowder. [music playing] And it spreads across the
continent, all the way to Europe in just 300 years. And in 1450, when
a German blacksmith named Johannes Gutenberg
develops a radically improved method of mechanical printing,
it becomes the greatest boost to collective learning
since the invention of writing 5,000 years before. [music playing] DAVID CHRISTIAN: Printing
encouraged mass education. Mass education encouraged
more exchanges of ideas and made the development of
new technological innovations, perhaps, slightly
easier in Europe than in other
parts of the world. [music playing] NARRATOR: Technology
tears down barriers. So after millennia of
discovery and invention, we're finally ready to conquer
Earth's greatest divide, the oceans. [music playing] For 15,000 years, the
oceans separate humanity into isolated zones, the
Americas, Africa and Eurasia, Australia, where we develop in
different worlds each unaware of the others. [music playing] But technology
ushers in a new age where nature's most formidable
barrier becomes a highway. Europeans crossed the
Atlantic for the first time. Equipped with a series of
big history's lucky breaks, they will dominate the
Americas, using horses, guns, and a terrible secret
weapon, disease. [music playing] The Europeans bring microbes
to which the Americans have no immunity. Within 100 years of Columbus,
up to 90% of them will die. It's a definitive conquest. [music playing] But by mastering
the ocean, European explorers unite the world. Mankind trades new crops,
animals, and resources, like gold and silver, in an
unprecedented global exchange. DAVID CHRISTIAN: The last
time in the planet's history when there was a biological
exchange over the whole globe, was 250 million years ago
when all the continents were gathered together in Pangea. But this time, it's
caused not by geology, but by human beings, by one
particular species that's moved goods all around the world. [music playing] NARRATOR: Our epic story has
taken us around the globe through seven thresholds. But what is the eighth and
final threshold in big history? And what secret
connects them all? [music playing] By the year 1500, mankind is
breaking the ocean barrier. [music playing] And these new liquid highways
amplify the very thing that makes man so special. The sharing and
spreading of knowledge. What big historians call
collective learning. DAVID CHRISTIAN: I think
globalization from 1500 is a sort of gear shift in the
speed of collective learning. [music playing] NARRATOR: This is the
first world wide web. [music playing] But the network is slow. Information, ideas,
inventions can only spread as fast as a horse
can run or a ship can sail. To circle the globe
takes over a year. [music playing] But soon, it all
begins to change. [music playing] By revealing connections
across space and time, big history shows how mankind
will cross another portal thanks to a
revolutionary machine. To create this
machine, big history connects metals
brought by meteors, ancient plants
reincarnated as coal, and the almost magical property
of water as its shape shifts into a new form. [music playing] That revolutionary
machine, the steam engine. CRAIG BENJAMIN: By heating water
you create this steam pressure. It can force a
piston, for example, to start moving up and down. Machines to drive spinning
machines, that will create textiles much much faster. [train whistle sounding] And then, you can put it
onto a platform with wheels and lay iron rails
across the landscape. All of this is a
product of utilizing this extraordinary property
of heated water again. [music playing] NARRATOR: The steam engine
leads to the gasoline engine, and ignites a new
threshold in big history, the modern revolution. [music playing] For all of history, we have
been limited almost completely to power from human and animal
muscles, wind and flowing water. Now, mechanical engines
fueled by the power of the sun captured
in ancient plants make us far more
productive and powerful. [music playing] By 1900, the world's
steam engines will equal the power
of five billion men. The modern revolution
accelerates everything. How we produce and grow things. [train chugging] How we travel and communicate. [beeping] And it elevates man
to a unique status in the story of our planet. DAVID CHRISTIAN: A single
species for the first time in almost four billion
years has become so powerful that it dominates the biosphere,
and that's a fantastically interesting period
in history, and we're living in it right now. [music playing] NARRATOR: It is an
era unlike any before. But power is not the only
key to open this portal. The other is information. [beeps] [music playing] Throughout all
previous history, we were tethered to our
voices, which could only travel as far as a sound
wave could carry them, a maximum of 600 feet. But now our voices and ideas
can ride on radio waves, made possible by the electromagnetic
force born in the Big Bang. [music playing] Today, there are 7 billion
cell phones in the world. One for every person on Earth. We are each connected to a
global network that transmits information at the
speed of light. DAVID CHRISTIAN: I mean, short
of teleportation, I really can't think of anything
more magical than that. [music playing] NARRATOR: In our modern
era, the pace of progress explodes leading to
a staggering fact. During the era of
the steam engine, it took 150 years for man's
collective knowledge to double. Today, it takes two years. By 2020, it will take 72 hours. [music playing] [explosion] Big history brings
us from the Big Bang, through a series of
amazing thresholds, to the world around us today. But can it foresee mankind's
next momentous turning points? And do they promise
even faster progress or the end of everything? [music playing] Big history tells the
story of everything, from the beginning
of the universe, to the world around us today
in what big historians call threshold moments. But what is the secret key,
the fundamental mystery that links them all together? [music playing] To reveal that
secret, we first have to understand a basic law
that governs everything in the universe. [music playing] The natural tendency
of all things is to move from order to
disorder, from structure to disintegration, from
the complex to the simple. An egg can break, but its
pieces can't form a new egg. A newspaper can burn
to ashes, but the ashes can't become a newspaper. Scientists call it
the law of entropy. [rattling] [music playing] Throughout all time
and space, the universe has been ruled by this law. But when we consider the
nearly 14 billion years of big history, we
discover would appear to be rare and remarkable exceptions. Moments when everything lines
up in just the right way and seems to defy this
natural law of entropy. [rumbling] To go from the massive
explosion of the Big Bang to the structure of a star,
from the swirl of chemicals in ancient seas to a
strand of living DNA, from a simple universe
to a complex world. [music playing] For big history, that is the
secret hidden in the heart of every threshold. A pattern that links us
through all of time and space. Eight moments when
the universe seems to defy its most basic law, and
instead moves from the simple to the complex. Eight moments when we
move from chaos to order. [music playing] But a mystery remains. How and why, in these instances,
did the universe seemingly defy its own law of chaos? [music playing] The answer lies in a cosmic
force that emerged from the Big Bang, gravity. [music playing] Because of gravity, our universe
is not evenly distributed. Instead, there are
hubs, galaxies, stars, and solar systems
divided by massive voids. [music playing] In those hubs, energy
and matter converge. Trillions of interactions occur. And in a swarming hub, the
improbable becomes possible. ALEX FILIPPENKO:
Gravity can form stars that form energy that bathes
the planets surrounding them, which gives rise to life. And life itself, then, has
all these interactions that lead to increasing complexity. DAVID CHRISTIAN: Most of the
universe is still very simple. So things get complex
only in particular pockets of the universe where we have
the Goldilocks conditions, where conditions
are just perfect. [music playing] NARRATOR: These hubs appear
throughout space and time, in stars that forge elements,
ancient seas that produce life, and even in cities on Earth. [music playing] ALEX FILIPPENKO:
Giant cities form with huge amounts of activity. And then, there, of course,
these great expanses and not much activity. All these things come about
as a result of just repeated interactions of particles
obeying the laws of physics. And there's just a
few laws of physics. [music playing] NARRATOR: So what is
the next threshold where life, complexity, and
thresholds go on forever? Or does big history
foresee new moments where mankind, life itself,
even the entire universe come to an end? [music playing] Big history has revealed
how a series of eight giant thresholds ultimately lead
to the advanced civilization that surrounds us today. But what thresholds
lie in the future? [birds chirping] [music playing] To be considered a
threshold in big history, an event has to alter things
fundamentally, irreversibly changing our modern world. So what thresholds lie ahead? What will the ninth be? [music playing] One possible
candidate, the point when humans begin to live
on other planets, like Mars. [music playing] Another possibility, the
moment our own technology overtakes us. Still, another
possible threshold would be discovering intelligent
creatures from other planets. [music playing] Or being discovered by them. [music playing] But we've also seen that
threshold moments can occur in the aftermath of catastrophe. Like a cosmic collision. DAVID CHRISTIAN: There was
still sort of rogue asteroids wandering around our Earth. [music playing] NARRATOR: Scientists calculate
that an asteroid six miles wide could wipe out humanity, just
as a similar impact wiped out the dinosaurs 65
million years ago. [music playing] [explosion] The explosion of a
nearby star could also cause a planet wide cataclysm. [roaring] But disaster doesn't
only come from space. [music playing] Here on Earth,
the next threshold might follow a worldwide
natural disaster. [music playing] Like the dawn of a new ice
age, or the toxic blast of a super massive volcano. [loud eruption] And even a cataclysm
of our own invention-- [roaring] From thermonuclear war-- [explosion and rumbling] To environmental destruction. [winds roaring] DAVID CHRISTIAN: But
on the other hand, the story of human innovation
is fantasticly creative. I mean, we are
staggeringly creative. We are so clever, as a result
of collective learning, that if our species can't
solve these problems, I have no idea who can. [music playing] NARRATOR: Big history
is about looking at our world and our
future in different ways. [music playing] On an astronomical scale
across billions of years, our fate is much more clear. Our story of moving from
simplicity to complexity is only temporary. [music playing] Billions of years from now, the
Sun will expand and sterilize the Earth. [roaring] CRAIG BENJAMIN: All the
seas will boil away. Then, the sun will shrink
and contract, and then end up as a white dwarf,
and then a black dwarf, no energy, just this dead,
lifeless object floating in space. [music playing] NARRATOR: Out in the
universe, already today, 90% of the material to make
new stars has been used up, so fewer will be formed. The story of the
universe, the series of thresholds that led
to our world today, will begin to reverse. [music playing] Instead of becoming
more complex, things will become more simple. DAVID CHRISTIAN: Stars
will stop forming. They will stop
creating new elements. ALEX FILIPPENKO: Eventually, if
the universe expands forever, it'll cool down to essentially
absolute zero everywhere. [music playing] The story of big
history will come to an end in a darkened cosmos
where nothing will be created. DAVID CHRISTIAN: And in
the far distant future, the universe is going to be
extraordinarily simple again, and it will cease to be able
to create complex things. So that means something quite
magical about the time we live in. We live in the springtime
of our universe. That's a time when our universe
was capable of creating beautiful things, like
hummingbirds, or redwoods, or you and me. [music playing] NARRATOR: And it's also the
time when mankind undertakes a profound quest, to
understand the big picture, to find our place in the
grand continuum of time. Our infinite linked to
the brilliant beginnings, the quiet end, and the
transformative power of this mysterious universe. [music playing] The story we call big history.
