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Must we die?
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Are there beings in the cosmos
who live forever...
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afloat on an endless journey
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down the river of time?
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"The Immortals"
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Our ancestors
marked the passage of time
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by the Moon and stars.
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But it was the people
who once lived here,
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around 5,000 years ago,
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who first starting
chopping up time
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into smaller bite-sized portions
of hours and minutes.
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They call this place Uruk.
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We call it Iraq.
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It's a part of Mesopotamia,
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the land between the Tigris
and the Euphrates rivers.
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The city was invented here.
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And one of humanity's
greatest victories was won
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in the ceaseless battle
against time.
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It was here that we learned
how to write.
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Death could
no longer silence us.
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And writing gave us the power
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to reach across the millennia
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and speak inside the heads
of the living.
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No one has ever spoken
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across a longer stretch
of time's river
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than this Akkadian princess,
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daughter of the first emperor
in history,
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and priestess of the Moon--
Enheduanna.
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For not only
did she write poetry,
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but Enheduanna did something
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no one before her
had ever done--
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she signed her name
to her work.
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She's the first person
for whom we can say
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we know who she was,
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and what she dreamed.
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She dreamt of stepping
through the Gate of Wonder.
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Here's a thought
Enheduanna sent
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across more than 4,000 years
to you.
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It's from her work entitled
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Lady of the Largest Heart.
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Innana, the planet Venus,
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goddess of love,
will have a great destiny
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throughout the entire universe.
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...throughout
the entire universe.
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And Uruk is also the place
where the epic tale
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of "The Hero's Journey"
was first written down.
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Before Batman, Luke Skywalker,
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Odysseus-- before them all--
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there was a man named Gilgamesh
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who left home on a quest
to vanquish time.
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Gilgamesh was searching
for immortality.
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He looked everywhere,
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gained complete wisdom,
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uncovered what was hidden.
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He brought back a tale of times
before the Great Flood.
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He built the Wall of Uruk,
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which no future king
will ever match.
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Read the story
of that man Gilgamesh,
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a hero born of Uruk,
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who went through all kinds
of sufferings.
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Who crossed the ocean,
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the broad seas,
as far as the sunrise;
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who inspected
the edges of the world,
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searching for eternal life.
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On his travels,
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Gilgamesh encountered
a wise man named Utnapishtim,
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who told him the story of a
flood that destroyed the world,
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and how one of the gods
instructed Utnapishtim
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to build an ark to rescue
his family and the animals.
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The earliest surviving account
of the flood legend
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was written down in Mesopotamia,
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a thousand years
before it was retold
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as the story of Noah
in the Old Testament.
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So, you could say Gilgamesh
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fulfilled his quest
for immortality.
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We still read
the Epic of Gilgamesh,
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and with every reader,
he lives again.
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And all those heroes and
superheroes who have come since
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follow in the footsteps
of the first hero's journey--
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another kind of immortality;
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a story sent from one
civilization to another
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across thousands of years.
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But life itself sends
its own stories
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across billions of years.
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It's a message that every
one of us carries inside,
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inscribed in all the cells
of our bodies,
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in a language that all life
on Earth can read.
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The genetic code
is written in an alphabet
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consisting of only four letters.
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Each letter is
a molecule made of atoms;
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each word is three letters long.
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Every living thing is
a masterpiece,
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written by nature
and edited by evolution;
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the instructions
for running and reproducing
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the intricate machinery of life.
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The essential message of life
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has been copied and recopied
for more than 3 billion years.
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But where did
that message come from?
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Nobody knows.
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Perhaps it began in a shallow,
sunlit pool, just like this.
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Somehow, carbon-rich molecules
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began using energy to make
crude copies of themselves.
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Some varieties were
better at making copies,
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and left more offspring.
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The competing molecules
became more elaborate.
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Evolution and life itself
was underway.
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Or life could've started
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in the searing heat
of a volcanic vent
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on the deep sea floor.
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Or is it possible
that life came to Earth
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as a hitchhiker?
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Let me tell you a story
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about a traveler
from another world.
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The peace of the Egyptian
village of Nakhla,
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near Alexandria,
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was abruptly shattered
on a June morning in 1911.
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Written in this meteorite was
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a message from another planet.
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But 70 years would pass
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before anyone could read it.
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In 1976,
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NASA landed two Viking
spacecraft on Mars.
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Carl Sagan took us there
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on our original journey
through the cosmos.
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We found that the Martian air
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was less than one percent
as dense as ours,
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and made mostly
of carbon dioxide.
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There were smaller amounts
of nitrogen,
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argon, water vapor and oxygen.
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A few years later,
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when scientists thought
to analyze the gasses
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trapped inside
the Nakhla meteorite,
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and other members of its class,
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they found
a striking similarity--
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the vast majority of meteorites
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are fragments of asteroids.
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But the kind
that hit Nakhla, on Earth,
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could only have come
from one place...
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Mars.
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Welcome to Mars.
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Over a billion years ago,
a volcano erupted here
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and its lava cooled
into solid rock.
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Hundreds of millions
of years later,
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this area was flooded
with water.
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And long after that flood,
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an asteroid the size of
the Rock of Gibraltar
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crashed into
the Martian surface,
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blasting out a huge crater.
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Much of the debris was ejected
back out into space,
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where it orbited the Sun
until a gravitational tug
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from its home planet, Mars,
diverted one of the boulders
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into a collision course
with Earth.
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Its arrival shook up
the little village of Nakhla.
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Meteorites of the type that
hit Nakhla
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are the vehicles of a natural
interplanetary transit system
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that sends rocks between
the planets.
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Such a meteorite can safely
shelter microscopic cargo--
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the seeds of life--
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an interplanetary ark.
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Most rocks are porous, full of
tiny nooks and crannies,
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where life can stow away.
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We know
that some microbes can survive
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the hostile environment
of space.
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Take these guys, for instance.
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These microbes spent a year
and a half riding
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on the outside of the
International Space Station,
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exposed to the extreme
temperatures, vacuum,
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and radiation of space.
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And some of them
were still alive and kicking
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when they were brought back
to Earth.
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Even more astonishing
are these creatures,
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awakened from a deathlike sleep
of eight million years.
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They were frozen
in the Antarctic ice
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millions of years before
our species even existed.
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And they're still alive.
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If life can withstand
the hardships of space
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and endure for millennia,
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then it could ride the natural
interplanetary transit system
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from world to world.
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It's a good bet
that our microbial ancestors
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spent some time in space.
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Why do we think so?
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The Earth is four-and-a-half-
billion-years old.
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For the first half
of its lifetime,
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large asteroids were bombarding
the planet
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every few million years.
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The most violent impacts
vaporized the oceans
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and even melted
the surface rock.
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Each such collision would have
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completely sterilized
the planet
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for thousands of years.
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But we know from fossils
in the rocks
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that bacteria were evolving
on Earth
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during this formative period.
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So how could life have survived
such a lethal series of blows?
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Whenever one
of those big asteroids
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hit the Earth, the explosion
would blast out a crater,
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launching millions of boulders
into space.
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Many of those rocks carried
living bacteria inside.
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Some of the bugs would have
survived in space,
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while all those left behind
on Earth would have been fried.
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A few thousand years
after each impact,
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the Earth would have
cooled down enough
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for water to condense
into oceans.
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The planet would again be
habitable.
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00:13:35,130 --> 00:13:38,332
Meanwhile, most of the rocks
launched into space
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would have been orbiting
the Sun.
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Some of them would encounter
the Earth again,
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00:13:45,373 --> 00:13:48,275
reenter the atmosphere
as meteorites,
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and deliver their precious
cargo of life
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00:13:50,812 --> 00:13:52,913
to re-seed the planet...
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00:13:55,016 --> 00:13:57,051
like Noah's ark.
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00:13:57,085 --> 00:13:59,286
What this means is that life
doesn't have
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00:13:59,321 --> 00:14:03,858
to start over again from
scratch after each catastrophe.
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It can pick up
where it left off.
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00:14:07,296 --> 00:14:09,463
When the solar system was young,
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00:14:09,498 --> 00:14:11,665
Venus was probably more
like Earth,
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00:14:11,700 --> 00:14:14,835
with oceans and maybe even life.
219
00:14:14,870 --> 00:14:18,139
Venus, Earth, and Mars
were all exchanging rocks
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00:14:18,173 --> 00:14:20,074
with each other,
due to asteroid impacts.
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Does life on Earth carry
any traces
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00:14:23,278 --> 00:14:25,880
of interplanetary voyages
made in the distant past?
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00:14:25,914 --> 00:14:29,250
Why is it
that some microbes can survive
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00:14:29,284 --> 00:14:32,653
the intense radiation
and vacuum of space?
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00:14:32,687 --> 00:14:36,023
These conditions don't naturally
exist on Earth.
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00:14:36,058 --> 00:14:37,925
Maybe those bugs are telling us
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00:14:37,959 --> 00:14:42,163
that their ancestors survived
those same conditions in space,
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00:14:42,197 --> 00:14:44,298
a few billion years ago.
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00:14:45,534 --> 00:14:48,002
So we know that microbes
can stow away in rocks
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00:14:48,036 --> 00:14:50,738
and survive the voyage
from planet to planet.
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00:14:50,772 --> 00:14:53,240
But what about trip
from star to star--
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00:14:53,275 --> 00:14:55,743
an interstellar odyssey?
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00:15:03,606 --> 00:15:05,674
The dandelion.
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00:15:05,709 --> 00:15:08,143
Around 30 million years ago,
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00:15:08,178 --> 00:15:11,680
it evolved another way to send
its own message of life
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00:15:11,715 --> 00:15:14,049
through space and time.
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00:15:21,791 --> 00:15:24,827
Each seedling
is a little paratrooper,
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floating on the wind,
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risking everything
for a safe place to land.
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00:15:30,567 --> 00:15:34,903
Updrafts can carry them
higher into the air.
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00:15:34,938 --> 00:15:36,338
A dandelion can travel dozens,
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00:15:36,373 --> 00:15:38,407
possibly hundreds
of kilometers,
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00:15:38,441 --> 00:15:42,945
even crossing over
mountain ranges.
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00:15:42,979 --> 00:15:47,750
Evolution has shaped it into
an exquisite flying machine.
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The seed is another kind or ark,
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00:15:50,487 --> 00:15:52,354
ensuring the survival
of its species
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by riding the currents of the
atmosphere to safe harbors.
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00:15:55,892 --> 00:15:59,228
Each seed
in its DNA carries a story,
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00:15:59,262 --> 00:16:02,431
the character and destiny
of the next dandelion--
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00:16:02,465 --> 00:16:06,235
life propagates
by retelling its story.
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00:16:08,171 --> 00:16:11,540
Is it possible that life
could survive the journey
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00:16:11,574 --> 00:16:13,542
from star to star?
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00:16:13,576 --> 00:16:16,412
The stars are about
a million times farther apart
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00:16:16,446 --> 00:16:18,981
from each other
than are the planets.
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00:16:19,015 --> 00:16:22,918
Space is so vast that it would
take billions of years
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00:16:22,953 --> 00:16:24,787
for a rock ejected
from the Earth
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00:16:24,821 --> 00:16:29,558
to collide with a planet
circling another star.
258
00:16:29,593 --> 00:16:32,561
Any stowaway microbes
would never survive
259
00:16:32,596 --> 00:16:34,897
the cosmic radiation
for that long.
260
00:16:34,931 --> 00:16:36,799
But there's a plausible scenario
261
00:16:36,833 --> 00:16:40,636
for how life could spread from
one solar system to another.
262
00:16:46,376 --> 00:16:48,744
The stars of the Milky Way
are drawn by gravity
263
00:16:48,778 --> 00:16:52,982
in their own enormous orbits
around its center.
264
00:16:53,016 --> 00:16:54,917
Our Sun, for example,
265
00:16:54,951 --> 00:16:59,622
takes some 225 million years
to complete a single orbit.
266
00:16:59,656 --> 00:17:02,858
During each revolution around
the galaxy,
267
00:17:02,893 --> 00:17:05,861
our solar system will
pass through two or three
268
00:17:05,896 --> 00:17:08,297
gigantic interstellar clouds,
269
00:17:08,331 --> 00:17:12,001
each of them
many light years across.
270
00:17:15,538 --> 00:17:19,775
Galaxies are
world-making machines.
271
00:17:19,809 --> 00:17:23,445
Our Milky Way has more than
100 of these vast clouds,
272
00:17:23,480 --> 00:17:26,048
a place where gas and dust
condense
273
00:17:26,082 --> 00:17:28,717
to form new stars and planets.
274
00:17:32,088 --> 00:17:34,390
In its travels
through the Milky Way,
275
00:17:34,424 --> 00:17:37,393
our Sun is accompanied not only
by its planets,
276
00:17:37,427 --> 00:17:40,930
but also by
a trillion distant comets.
277
00:17:42,899 --> 00:17:46,202
When our solar system passes
through an interstellar cloud,
278
00:17:46,236 --> 00:17:48,504
the gravity of
the massive cloud
279
00:17:48,538 --> 00:17:52,208
stirs up the outermost comets.
280
00:17:52,242 --> 00:17:55,010
Some comets will be hurled out
281
00:17:55,045 --> 00:17:57,580
into the space
between the stars.
282
00:17:59,583 --> 00:18:02,017
Others will plunge inward...
283
00:18:04,387 --> 00:18:06,889
falling towards the Sun.
284
00:18:22,873 --> 00:18:26,075
And some of them may collide
with the planets.
285
00:18:27,644 --> 00:18:31,180
The high-speed impact
of a comet with a rocky planet
286
00:18:31,214 --> 00:18:34,617
will launch boulders
like rockets into space.
287
00:18:34,651 --> 00:18:37,520
If that planet should
happen to be inhabited,
288
00:18:37,554 --> 00:18:40,222
many of those rocks
will carry passengers--
289
00:18:40,257 --> 00:18:42,558
living microbes.
290
00:18:42,592 --> 00:18:44,527
After thousands of years,
291
00:18:44,561 --> 00:18:46,862
fragments of the rocks
ejected from Earth
292
00:18:46,897 --> 00:18:51,300
can fall as meteors into the
atmospheres of newborn planets
293
00:18:51,334 --> 00:18:53,569
in the interstellar cloud.
294
00:19:00,510 --> 00:19:02,077
If the stowaway microbes
295
00:19:02,112 --> 00:19:04,947
should happen to come
in contact with liquid water,
296
00:19:04,981 --> 00:19:08,551
they can revive and reproduce.
297
00:19:08,585 --> 00:19:11,220
This may be
how life comes barreling
298
00:19:11,254 --> 00:19:13,589
into the barren places.
299
00:19:13,623 --> 00:19:16,125
The sun emerges from the cloud,
300
00:19:16,159 --> 00:19:17,760
having scattered
the seeds of life
301
00:19:17,794 --> 00:19:21,397
among the newborn worlds
of other stars.
302
00:19:21,431 --> 00:19:24,467
Those new worlds,
now touched by life,
303
00:19:24,501 --> 00:19:26,068
will then leave
their birth cloud
304
00:19:26,102 --> 00:19:28,270
and go their separate ways.
305
00:19:28,305 --> 00:19:30,739
Eventually, their stars
will carry them
306
00:19:30,774 --> 00:19:32,174
through
other interstellar clouds,
307
00:19:32,209 --> 00:19:36,011
where they may seed
still more new worlds.
308
00:19:36,046 --> 00:19:41,484
Imagine this process
repeated from world to world,
309
00:19:41,518 --> 00:19:44,687
each one bringing life
to others.
310
00:19:50,694 --> 00:19:54,663
Life would then propagate,
like a slow chain reaction,
311
00:19:54,698 --> 00:19:57,032
through the entire galaxy.
312
00:20:01,705 --> 00:20:05,708
This could be
how life came to Earth.
313
00:20:05,742 --> 00:20:07,710
We do not know for sure.
314
00:20:07,744 --> 00:20:11,380
Are there any beings
out there like us?
315
00:20:11,414 --> 00:20:13,349
Do they ask the same questions?
316
00:20:13,383 --> 00:20:15,050
Do they share our fears?
317
00:20:16,386 --> 00:20:18,020
Do they have heroes
and adventures?
318
00:20:23,393 --> 00:20:27,229
If they do exist,
where are they?
319
00:20:27,264 --> 00:20:29,765
How might they make
their presence known?
320
00:20:45,882 --> 00:20:49,218
How did we first announce
our presence to the galaxy?
321
00:20:49,252 --> 00:20:54,924
It was 1946, the year after
the Second World War ended.
322
00:20:57,527 --> 00:20:59,528
The vivid imaginations
323
00:20:59,563 --> 00:21:01,363
of HG Wells and Buck Rogers
324
00:21:01,398 --> 00:21:03,265
never cooked up a more
fantastic experience
325
00:21:03,300 --> 00:21:05,868
than the Army engineers
326
00:21:05,902 --> 00:21:08,070
at their laboratory
in Belmar, New Jersey.
327
00:21:08,105 --> 00:21:10,072
It opens up
unlimited possibilities
328
00:21:10,107 --> 00:21:11,907
for interstellar experiment.
329
00:21:11,942 --> 00:21:13,175
American engineers
330
00:21:13,210 --> 00:21:15,778
bounced a beam
of radio waves off the Moon,
331
00:21:15,812 --> 00:21:18,013
and were able
to detect its echo.
332
00:21:24,788 --> 00:21:27,790
They called this experiment
Project Diana.
333
00:21:27,824 --> 00:21:29,458
It was the first
interstellar message
334
00:21:29,493 --> 00:21:31,527
ever sent by our species...
335
00:21:33,997 --> 00:21:35,998
an eerie, tolling bell.
336
00:21:37,667 --> 00:21:41,404
If one allows
the imagination free reign,
337
00:21:41,438 --> 00:21:44,640
many future
possibilities appear.
338
00:21:46,676 --> 00:21:49,445
Spaceships, carrying passengers
339
00:21:49,479 --> 00:21:51,380
at thousands of miles per hour,
340
00:21:51,415 --> 00:21:53,282
can be controlled
341
00:21:53,316 --> 00:21:55,451
and communication established
342
00:21:55,485 --> 00:21:57,153
with their passengers,
343
00:21:57,187 --> 00:21:59,822
for we now know that
the Earth's atmosphere
344
00:21:59,856 --> 00:22:01,691
can be penetrated.
345
00:22:07,364 --> 00:22:09,598
Traveling at
the speed of light,
346
00:22:09,633 --> 00:22:10,933
it takes just over one second
347
00:22:10,967 --> 00:22:13,135
for a radio wave
to reach the lunar surface.
348
00:22:14,705 --> 00:22:18,607
But the expanding wavefront
is much bigger than the Moon.
349
00:22:18,642 --> 00:22:21,143
Most of the wave
passes right by it,
350
00:22:21,178 --> 00:22:23,546
but the central part
gets bounced back.
351
00:22:25,449 --> 00:22:28,417
After a round-trip travel time
of two and a half seconds,
352
00:22:28,452 --> 00:22:29,785
it hits our planet.
353
00:22:31,188 --> 00:22:33,189
Project Diana transmitted
354
00:22:33,223 --> 00:22:34,991
a series of powerful
radio waves--
355
00:22:35,025 --> 00:22:36,425
one every four seconds--
356
00:22:36,460 --> 00:22:38,594
to "ping" the Moon.
357
00:22:40,864 --> 00:22:44,467
The parts that missed the Moon
are traveling still.
358
00:22:47,237 --> 00:22:49,138
It was just the beginning.
359
00:22:49,172 --> 00:22:50,706
After World War II,
360
00:22:50,741 --> 00:22:53,809
television stations cropped up
all over the United States,
361
00:22:53,844 --> 00:22:55,144
and other parts of the world.
362
00:22:56,880 --> 00:22:58,681
The Project Diana message
363
00:22:58,715 --> 00:23:01,651
and the FM radio, television
and radar signals
364
00:23:01,685 --> 00:23:03,119
of the 20th century
365
00:23:03,153 --> 00:23:05,154
all move outward
at the speed of light.
366
00:23:05,188 --> 00:23:09,458
These transmissions make up
a vast sphere of radio waves,
367
00:23:09,493 --> 00:23:12,495
expanding away from the Earth
in all directions.
368
00:23:12,529 --> 00:23:14,530
You could say that our world
369
00:23:14,564 --> 00:23:17,667
is radiating stories.
370
00:23:17,701 --> 00:23:20,836
Our ancestors etched
the story of Gilgamesh
371
00:23:20,871 --> 00:23:22,672
into clay tablets,
372
00:23:22,706 --> 00:23:25,641
sending that epic tale
into the future.
373
00:23:25,676 --> 00:23:28,511
We've encoded our stories
in radio waves
374
00:23:28,545 --> 00:23:30,413
and beamed them into space.
375
00:23:30,447 --> 00:23:32,982
They cover one light-year
of distance--
376
00:23:33,016 --> 00:23:35,351
that's six trillion miles--
377
00:23:35,385 --> 00:23:37,820
for every year of time
since they were sent.
378
00:23:37,854 --> 00:23:40,323
We've been sending
our stories into space
379
00:23:40,357 --> 00:23:42,158
for over 70 years.
380
00:23:42,192 --> 00:23:43,826
The leading edge
of these signals
381
00:23:43,860 --> 00:23:45,528
has already washed over
382
00:23:45,562 --> 00:23:47,830
thousands of planets
of other stars.
383
00:23:47,864 --> 00:23:49,932
If any of these worlds are home
384
00:23:49,967 --> 00:23:52,501
to a civilization
with radio telescopes,
385
00:23:52,536 --> 00:23:55,438
they could already know
that we're here.
386
00:23:58,809 --> 00:24:01,043
What if other worlds
are sending
387
00:24:01,078 --> 00:24:03,079
their stories into space?
388
00:24:04,715 --> 00:24:07,083
Since 1960,
we've been listening
389
00:24:07,117 --> 00:24:09,218
for extraterrestrial
radio signals
390
00:24:09,252 --> 00:24:12,521
without hearing so much
as a tolling bell.
391
00:24:12,556 --> 00:24:15,224
But our search
has been sporadic
392
00:24:15,258 --> 00:24:17,460
and limited to
certain parts of the sky.
393
00:24:22,599 --> 00:24:24,066
For all we know,
394
00:24:24,101 --> 00:24:26,736
we may have just missed
an alien signal,
395
00:24:26,770 --> 00:24:28,304
looking in the wrong place
396
00:24:28,338 --> 00:24:30,473
at the wrong time.
397
00:24:30,507 --> 00:24:32,608
We've only listened to
a miniscule fraction
398
00:24:32,643 --> 00:24:34,310
of the stars in our galaxy.
399
00:24:34,344 --> 00:24:35,978
And there may be
another problem...
400
00:24:36,013 --> 00:24:37,813
we are, to some extent,
401
00:24:37,848 --> 00:24:39,782
prisoners of our own
moment in time
402
00:24:39,816 --> 00:24:41,717
and the limits
of our technology.
403
00:24:41,752 --> 00:24:44,220
Radio and television
broadcasting
404
00:24:44,254 --> 00:24:46,656
may be only
a brief passing phase
405
00:24:46,690 --> 00:24:49,325
in our technological
development.
406
00:24:49,359 --> 00:24:52,061
When we imagine
alien civilizations
407
00:24:52,095 --> 00:24:54,497
broadcasting signals
with radio telescopes,
408
00:24:54,531 --> 00:24:57,733
are we any different
from earlier generations
409
00:24:57,768 --> 00:25:01,270
who imagined riding
cannon shells to the Moon?
410
00:25:02,773 --> 00:25:05,708
Civilizations even slightly
more advanced than ours
411
00:25:05,710 --> 00:25:07,343
may have already moved on
412
00:25:07,345 --> 00:25:10,079
to some other mode
of communication,
413
00:25:10,081 --> 00:25:11,981
one that we have
yet to discover
414
00:25:11,983 --> 00:25:13,983
or even imagine.
415
00:25:13,985 --> 00:25:15,551
Their messages could be
416
00:25:15,553 --> 00:25:17,320
swirling around us,
at this very moment,
417
00:25:17,322 --> 00:25:20,990
but we lack the means
to perceive them,
418
00:25:20,992 --> 00:25:22,758
just as all of our ancestors,
419
00:25:22,760 --> 00:25:24,527
up to a little more
than a century ago,
420
00:25:24,529 --> 00:25:27,730
would have been oblivious to
the most urgent radio signal
421
00:25:27,732 --> 00:25:30,600
from another world.
422
00:25:30,602 --> 00:25:33,769
But there's another,
more troubling possibility--
423
00:25:33,771 --> 00:25:36,539
civilizations,
like other living things,
424
00:25:36,541 --> 00:25:39,275
may only live so long
before perishing
425
00:25:39,309 --> 00:25:41,544
due to natural causes,
or violence,
426
00:25:41,578 --> 00:25:43,879
or self-inflicted wounds.
427
00:25:43,914 --> 00:25:46,215
Whether or not
we ever make contact
428
00:25:46,250 --> 00:25:47,650
with intelligent alien life
429
00:25:47,684 --> 00:25:50,119
may depend on
a critical question.
430
00:25:50,153 --> 00:25:54,257
What is the life expectancy
of a civilization?
431
00:26:17,871 --> 00:26:20,010
By the time of Enheduanna,
432
00:26:20,045 --> 00:26:22,211
the first person
to ever get a writing credit,
433
00:26:22,245 --> 00:26:25,314
civilization was already
more than 1,000 years old.
434
00:26:27,350 --> 00:26:31,654
But today, her glorious city
is a barren wasteland.
435
00:26:31,688 --> 00:26:33,088
What went wrong?
436
00:26:33,123 --> 00:26:35,457
One problem was
the almost ceaseless warfare
437
00:26:35,492 --> 00:26:37,726
between the cities
of Mesopotamia,
438
00:26:37,761 --> 00:26:40,396
which continually destroyed
their achievements.
439
00:26:40,430 --> 00:26:42,564
They glorified military conquest
440
00:26:42,599 --> 00:26:46,001
and ultimately
became its victims.
441
00:26:48,438 --> 00:26:50,472
Another cause of decline
442
00:26:50,507 --> 00:26:52,174
was that their
technical know-how
443
00:26:52,208 --> 00:26:54,643
overran their
understanding of nature.
444
00:26:54,678 --> 00:26:57,346
The ingenious irrigation system
that was the basis
445
00:26:57,380 --> 00:26:59,848
for the great civilizations
of Mesopotamia
446
00:26:59,883 --> 00:27:01,817
had an unintended consequence--
447
00:27:01,851 --> 00:27:05,187
the water channeled into
their farmlands every year
448
00:27:05,221 --> 00:27:08,824
evaporated and left
its salt behind.
449
00:27:08,858 --> 00:27:11,427
Over generations,
the salt accumulated
450
00:27:11,461 --> 00:27:13,262
and began to kill the crops.
451
00:27:13,296 --> 00:27:16,532
And then, about 2,200 BC,
452
00:27:16,566 --> 00:27:18,867
not long after
the time of Enheduanna,
453
00:27:18,902 --> 00:27:20,803
disaster struck...
454
00:27:20,837 --> 00:27:23,939
a drought of truly
epic proportions,
455
00:27:23,974 --> 00:27:25,507
lasting for many decades.
456
00:27:25,542 --> 00:27:27,443
The rains stopped,
crops withered,
457
00:27:27,477 --> 00:27:28,944
and there was famine
and anarchy.
458
00:27:28,979 --> 00:27:30,779
Barbarians invaded.
459
00:27:30,814 --> 00:27:34,450
The streets of many cities
were littered with dead.
460
00:27:34,484 --> 00:27:36,352
There could be only
one explanation.
461
00:27:36,386 --> 00:27:38,354
Enlil, the supreme god,
462
00:27:38,388 --> 00:27:40,956
was angry because
one of his temples
463
00:27:40,991 --> 00:27:42,458
had been destroyed.
464
00:27:42,492 --> 00:27:45,794
The people of Mesopotamia
could not know
465
00:27:45,829 --> 00:27:47,529
that the same drought
was crushing
466
00:27:47,564 --> 00:27:49,498
the dawning civilizations
of Egypt,
467
00:27:49,532 --> 00:27:51,133
Greece, India,
468
00:27:51,167 --> 00:27:52,835
Pakistan and China.
469
00:27:52,869 --> 00:27:54,536
All the gods of the Earth
470
00:27:54,571 --> 00:27:57,473
must have been really angry
about something.
471
00:27:57,507 --> 00:27:58,908
For all their brilliance,
472
00:27:58,942 --> 00:28:00,576
the people of
those civilizations
473
00:28:00,610 --> 00:28:02,811
had no inkling
they were experiencing
474
00:28:02,846 --> 00:28:05,047
abrupt climate change.
475
00:28:08,919 --> 00:28:11,186
3,000 years later, the climate
476
00:28:11,221 --> 00:28:14,156
would change abruptly for
another glorious civilization,
477
00:28:14,190 --> 00:28:16,258
this one in Central America.
478
00:28:16,293 --> 00:28:17,693
At its peak,
479
00:28:17,727 --> 00:28:19,862
the Mayan civilization
perished,
480
00:28:19,896 --> 00:28:22,364
wiped out by a series
of severe droughts
481
00:28:22,399 --> 00:28:23,766
over the course of a century.
482
00:28:23,800 --> 00:28:26,268
We still carry within us
483
00:28:26,303 --> 00:28:29,004
the echoes of these
extinct civilizations
484
00:28:29,039 --> 00:28:31,740
in our languages and our myths.
485
00:28:31,775 --> 00:28:35,678
Today, we have a single
global civilization.
486
00:28:35,712 --> 00:28:37,513
How long will it live?
487
00:28:37,547 --> 00:28:41,083
There are so many ways
for a civilization to die.
488
00:28:41,117 --> 00:28:42,518
Let's start with the ones
489
00:28:42,552 --> 00:28:44,553
that we probably wouldn't
be able to do much about.
490
00:28:46,790 --> 00:28:50,392
That supernova
is 1,000 light-years away.
491
00:28:50,427 --> 00:28:52,561
If it were much closer, say...
492
00:28:52,596 --> 00:28:55,064
less than 30 light-years
from Earth,
493
00:28:55,098 --> 00:28:57,366
its cosmic radiation
would shred
494
00:28:57,400 --> 00:28:59,435
the atmosphere's
protective ozone layer
495
00:28:59,469 --> 00:29:01,637
and destroy our civilization.
496
00:29:01,671 --> 00:29:05,140
Lucky for us, none of the stars
close enough to harm us
497
00:29:05,175 --> 00:29:06,909
are likely to go supernova
498
00:29:06,943 --> 00:29:09,311
any time in the next
few hundred million years.
499
00:29:15,252 --> 00:29:17,052
Every million years or so,
500
00:29:17,087 --> 00:29:20,789
a supervolcano erupts
somewhere on Earth.
501
00:29:20,824 --> 00:29:25,094
The last time it happened
was 74,000 years ago,
502
00:29:25,128 --> 00:29:26,595
on the island of Sumatra,
503
00:29:26,630 --> 00:29:29,498
in what is now Indonesia.
504
00:29:29,533 --> 00:29:31,433
It spewed
hundreds of times more
505
00:29:31,468 --> 00:29:33,402
rock, ash and toxic gas
506
00:29:33,436 --> 00:29:36,605
than any single volcano
in recorded history.
507
00:29:36,640 --> 00:29:40,009
The molten rock that erupted
from Earth's crust
508
00:29:40,043 --> 00:29:41,911
left this caldera,
509
00:29:41,945 --> 00:29:43,646
100 kilometers long,
510
00:29:43,680 --> 00:29:45,815
now filled with a lake.
511
00:29:48,785 --> 00:29:53,589
The Toba volcano sent
more than 600 cubic miles
512
00:29:53,623 --> 00:29:56,625
of pulverized rock
soaring skyward.
513
00:29:56,660 --> 00:30:00,463
The westward wind carried the
volcanic ash over India,
514
00:30:00,497 --> 00:30:02,531
where it fell out
in a smothering blanket
515
00:30:02,566 --> 00:30:05,334
over the subcontinent.
516
00:30:05,368 --> 00:30:07,937
The eruption loaded
the upper atmosphere
517
00:30:07,971 --> 00:30:09,672
with sulfur gases.
518
00:30:09,706 --> 00:30:11,640
The result was a global haze
519
00:30:11,675 --> 00:30:13,542
that blocked most
of the sunlight
520
00:30:13,577 --> 00:30:16,111
from reaching the surface
for at least five years.
521
00:30:16,146 --> 00:30:19,415
It was like one
five-year-long cloudy day.
522
00:30:20,684 --> 00:30:23,519
This so-called
"volcanic winter"
523
00:30:23,553 --> 00:30:27,556
resembled a "nuclear winter,"
but without the radiation.
524
00:30:28,592 --> 00:30:31,026
Temperatures fell everywhere.
525
00:30:31,061 --> 00:30:33,662
Plants and animals froze
even in the tropics,
526
00:30:33,697 --> 00:30:35,564
dying in enormous numbers.
527
00:30:35,599 --> 00:30:37,066
But life is hardy.
528
00:30:37,100 --> 00:30:40,136
Only a few species
were driven to extinction.
529
00:30:40,170 --> 00:30:42,705
One of our ancestors
in central India
530
00:30:42,739 --> 00:30:44,140
sharpened this stone blade
531
00:30:44,174 --> 00:30:46,542
in the years before
the Toba eruption.
532
00:30:46,576 --> 00:30:48,711
And this blade
533
00:30:48,745 --> 00:30:50,312
was one of dozens
that were found
534
00:30:50,347 --> 00:30:52,982
in the soil layer
above the volcanic fallout.
535
00:30:53,016 --> 00:30:55,484
This tells us that
some toolmakers,
536
00:30:55,519 --> 00:30:58,020
even in the area directly
affected by the volcano,
537
00:30:58,054 --> 00:31:00,156
managed to survive
the cataclysm.
538
00:31:00,190 --> 00:31:02,725
But the global human population
539
00:31:02,759 --> 00:31:05,027
must have plummeted
before rebounding.
540
00:31:05,061 --> 00:31:08,030
If an eruption like this
were to happen tomorrow,
541
00:31:08,064 --> 00:31:10,833
our civilization
would be brought to its knees,
542
00:31:10,867 --> 00:31:14,103
although the human species
would survive.
543
00:31:16,373 --> 00:31:18,507
I can imagine that
our technology
544
00:31:18,542 --> 00:31:20,209
of a few hundred years from now
545
00:31:20,243 --> 00:31:21,710
would allow us to siphon off
546
00:31:21,745 --> 00:31:23,746
the energy of
a threatening supervolcano
547
00:31:23,780 --> 00:31:25,581
before it explodes.
548
00:31:25,615 --> 00:31:28,084
We could then use that energy
for our own purposes.
549
00:31:28,118 --> 00:31:30,886
About once every million years,
a small asteroid
550
00:31:30,921 --> 00:31:32,521
collides with the Earth,
551
00:31:32,556 --> 00:31:34,924
causing a similar amount
of devastation.
552
00:31:34,958 --> 00:31:36,959
With our current science
and technology,
553
00:31:36,993 --> 00:31:39,895
we already know how to prevent
an asteroid impact.
554
00:31:39,930 --> 00:31:41,964
We would see it coming
years in advance
555
00:31:41,998 --> 00:31:43,599
and could send
a spacecraft there
556
00:31:43,633 --> 00:31:45,901
to deflect it into
a harmless orbit.
557
00:31:45,936 --> 00:31:47,970
With the technology
of a thousand years from now,
558
00:31:48,004 --> 00:31:50,806
we might even be able
to mitigate the deadly effects
559
00:31:50,841 --> 00:31:53,743
of a nearby supernova
on Earth's atmosphere.
560
00:31:53,777 --> 00:31:55,911
But what happens
561
00:31:55,946 --> 00:31:58,381
when the danger
to a civilization is invisible?
562
00:31:58,415 --> 00:32:00,116
When no one can see it coming?
563
00:32:09,484 --> 00:32:10,784
Beginning with Columbus,
564
00:32:10,819 --> 00:32:12,887
the European invaders
of the Americas
565
00:32:12,921 --> 00:32:16,790
had a secret weapon that even
they knew nothing about.
566
00:32:16,825 --> 00:32:19,727
They were carrying
bacteria and viruses
567
00:32:19,761 --> 00:32:21,862
for deadly diseases,
such as smallpox,
568
00:32:21,897 --> 00:32:25,799
that the original Americans
had never been exposed to.
569
00:32:25,834 --> 00:32:27,801
The Europeans like to believe
570
00:32:27,836 --> 00:32:29,837
that it was their valor
and superior weapons
571
00:32:29,871 --> 00:32:32,706
and culture
that won them the New World.
572
00:32:32,741 --> 00:32:34,975
The real conquistadors were
573
00:32:35,010 --> 00:32:37,244
the armies of the pathogens
that raced on ahead
574
00:32:37,279 --> 00:32:41,081
to infect and kill nine out
of ten of all the Indians
575
00:32:41,116 --> 00:32:43,884
of North, Central
and South America.
576
00:32:45,554 --> 00:32:47,321
The great civilizations
of the New World
577
00:32:47,355 --> 00:32:50,825
crumbled under the onslaught
of invading microbes.
578
00:32:50,859 --> 00:32:52,860
Without his invisible army,
579
00:32:52,894 --> 00:32:54,929
Cortez and those who followed
580
00:32:54,963 --> 00:32:58,732
might never
have stood a chance.
581
00:32:58,767 --> 00:33:02,269
But what about civilizations
that self-destruct?
582
00:33:10,479 --> 00:33:13,080
Our economic systems were
formed when the planet
583
00:33:13,114 --> 00:33:15,950
and its air, rivers,
oceans, lands,
584
00:33:15,984 --> 00:33:19,753
all seemed infinite.
585
00:33:19,788 --> 00:33:22,690
They evolved long before
we first saw the Earth
586
00:33:22,724 --> 00:33:26,393
as the tiny organism
that it actually is.
587
00:33:26,428 --> 00:33:28,062
They're all alike
in one respect...
588
00:33:28,096 --> 00:33:29,730
they're profit-driven,
589
00:33:29,764 --> 00:33:33,501
and therefore,
focused on short-term gain.
590
00:33:59,995 --> 00:34:01,996
The prevailing
economic systems,
591
00:34:02,030 --> 00:34:04,498
no matter what
their ideologies,
592
00:34:04,533 --> 00:34:06,233
have no built-in mechanisms
593
00:34:06,268 --> 00:34:08,269
for protecting our descendants
594
00:34:08,303 --> 00:34:10,304
of even 100 years from now,
595
00:34:10,338 --> 00:34:12,706
let alone, 100,000.
596
00:34:17,712 --> 00:34:19,680
In one respect, we're ahead
597
00:34:19,714 --> 00:34:21,982
of the people
of Ancient Mesopotamia.
598
00:34:22,017 --> 00:34:25,953
Unlike them, we understand
what's happening to our world.
599
00:34:25,987 --> 00:34:28,322
For example,
we're pumping greenhouse gasses
600
00:34:28,356 --> 00:34:30,925
into our atmosphere
at a rate not seen on Earth
601
00:34:30,959 --> 00:34:32,426
for a million years.
602
00:34:32,461 --> 00:34:34,161
And the scientific consensus
603
00:34:34,196 --> 00:34:36,363
that we're destabilizing
our climate.
604
00:34:36,398 --> 00:34:40,301
Yet our civilization seems
to be in the grip of denial;
605
00:34:40,335 --> 00:34:42,837
a kind of paralysis.
606
00:34:42,871 --> 00:34:44,872
There's a disconnect
between what we know
607
00:34:44,906 --> 00:34:46,907
and what we do.
608
00:34:49,811 --> 00:34:53,481
Being able to adapt
our behavior to challenges
609
00:34:53,515 --> 00:34:57,685
is as good a definition
of intelligence as any I know.
610
00:35:01,890 --> 00:35:05,826
If our greater intelligence
is the hallmark of our species,
611
00:35:05,861 --> 00:35:07,328
then we should use it,
612
00:35:07,362 --> 00:35:09,463
as all other beings use their
distinctive advantages--
613
00:35:09,498 --> 00:35:11,899
to help ensure
that their offspring prosper,
614
00:35:11,933 --> 00:35:14,168
and their heredity
is passed on,
615
00:35:14,202 --> 00:35:18,539
and that the fabric of nature
that sustains us is protected.
616
00:35:18,573 --> 00:35:21,375
Human intelligence
is imperfect, surely,
617
00:35:21,410 --> 00:35:23,811
and newly arisen.
618
00:35:23,845 --> 00:35:26,714
The ease with which it can be
sweet-talked, overwhelmed,
619
00:35:26,748 --> 00:35:28,649
or subverted by other
hard-wired tendencies,
620
00:35:28,683 --> 00:35:32,586
sometimes themselves disguised
as the light of reason,
621
00:35:32,621 --> 00:35:34,822
is worrisome.
622
00:35:34,856 --> 00:35:37,091
But if our intelligence
is the only edge,
623
00:35:37,125 --> 00:35:38,726
we must learn to use it better.
624
00:35:38,760 --> 00:35:40,494
To sharpen it.
625
00:35:40,529 --> 00:35:42,830
To understand its limitations
and deficiencies.
626
00:35:42,864 --> 00:35:46,734
To use it as cats use stealth
before pouncing.
627
00:35:46,768 --> 00:35:49,336
As walking sticks
use camouflage.
628
00:35:49,371 --> 00:35:52,540
To make it the tool
of our survival.
629
00:35:52,574 --> 00:35:54,608
If we do this, we can solve
630
00:35:54,643 --> 00:35:57,378
almost any problem
we are likely to confront
631
00:35:57,412 --> 00:35:59,747
in the next 100,000 years.
632
00:36:06,388 --> 00:36:08,522
And now we've arrived
at the place
633
00:36:08,557 --> 00:36:11,025
where our ancient dreams
of immortality
634
00:36:11,059 --> 00:36:14,628
and modern astrophysics
converge.
635
00:36:14,663 --> 00:36:16,731
Giant elliptical galaxies
636
00:36:16,765 --> 00:36:19,266
are something like... Florida,
637
00:36:19,301 --> 00:36:23,003
where the oldest stars
in the universe may be found.
638
00:36:28,744 --> 00:36:30,878
This is a red dwarf star,
639
00:36:30,912 --> 00:36:33,581
smaller and fainter
than our Sun.
640
00:36:33,615 --> 00:36:38,085
Red dwarfs are by far the most
plentiful stars in the cosmos.
641
00:36:38,120 --> 00:36:40,221
Unlike the Sun, which is
halfway through
642
00:36:40,255 --> 00:36:42,223
its 10-billion-year lifetime,
643
00:36:42,257 --> 00:36:45,159
red dwarfs will continue
to provide light and warmth
644
00:36:45,193 --> 00:36:48,095
to their planets
for trillions of years.
645
00:36:48,130 --> 00:36:49,764
That's hundreds of times longer
646
00:36:49,798 --> 00:36:52,900
than the present age
of the universe.
647
00:36:52,934 --> 00:36:54,735
What would
intelligent beings do
648
00:36:54,770 --> 00:36:56,237
if they had an eternity
649
00:36:56,271 --> 00:36:59,573
to develop their understanding
of the universe?
650
00:36:59,608 --> 00:37:01,809
Perhaps they would learn
how to open shortcuts
651
00:37:01,843 --> 00:37:03,978
in the fabric of spacetime,
652
00:37:04,012 --> 00:37:05,913
to travel between galaxies
653
00:37:05,947 --> 00:37:07,748
faster than the speed of light.
654
00:37:07,783 --> 00:37:10,618
Maybe they would create
whole new universes
655
00:37:10,652 --> 00:37:14,121
as artistic
or scientific experiments.
656
00:37:14,156 --> 00:37:16,991
Of course no one,
or at least nobody on Earth,
657
00:37:17,025 --> 00:37:19,794
knows what
the immortals might do.
658
00:37:21,029 --> 00:37:25,099
If one allows
the imagination free reign.
659
00:37:25,133 --> 00:37:26,801
But what about us?
660
00:37:29,838 --> 00:37:32,173
What is our own future?
661
00:37:32,207 --> 00:37:34,208
What would the Cosmic Calendar
662
00:37:34,242 --> 00:37:37,979
of the next 14 billion years
look like?
663
00:37:52,516 --> 00:37:54,350
If the original Cosmic Calendar
664
00:37:54,384 --> 00:37:56,853
includes all of time
from the birth of the universe
665
00:37:56,887 --> 00:37:58,821
until this very moment...
666
00:37:58,856 --> 00:38:01,724
what would
the Cosmic Calendar look like
667
00:38:01,758 --> 00:38:05,528
for the next 14 billion years?
668
00:38:05,562 --> 00:38:07,997
Just as with
the Cosmic Calendar of the past,
669
00:38:08,031 --> 00:38:10,299
every month the future calendar
670
00:38:10,334 --> 00:38:12,501
equals about a billion years;
671
00:38:12,536 --> 00:38:15,438
every day, some 40 million.
672
00:38:16,673 --> 00:38:19,509
Science makes it possible
for us to foretell
673
00:38:19,543 --> 00:38:21,544
certain astronomical events
674
00:38:21,578 --> 00:38:24,547
in the unimaginably
distant future--
675
00:38:24,581 --> 00:38:26,849
the death of the Sun,
for example.
676
00:38:26,884 --> 00:38:29,252
In some five billion years,
677
00:38:29,286 --> 00:38:32,522
our star will have
exhausted its hydrogen--
678
00:38:32,556 --> 00:38:34,590
the nuclear fuel
that powers it--
679
00:38:34,625 --> 00:38:36,759
becoming a red giant.
680
00:38:36,793 --> 00:38:38,828
I know that sounds depressing,
681
00:38:38,862 --> 00:38:41,731
but if we apply our
intelligence, our descendants
682
00:38:41,765 --> 00:38:44,834
of that distant future
will have long departed
683
00:38:44,868 --> 00:38:47,670
from the lost worlds
of the Sun.
684
00:38:47,704 --> 00:38:49,505
Who knows?
685
00:38:49,540 --> 00:38:51,541
Human events entail
too many variables,
686
00:38:51,575 --> 00:38:53,276
too many uncertainties,
687
00:38:53,310 --> 00:38:55,845
to make scientific statements
about our future.
688
00:38:55,879 --> 00:38:57,947
But we can still dream.
689
00:38:57,981 --> 00:39:00,716
The next golden age
of human achievement
690
00:39:00,751 --> 00:39:02,919
begins here and now--
691
00:39:02,953 --> 00:39:06,889
New Year's Day
of the next cosmic year.
692
00:39:06,924 --> 00:39:09,025
In the first tenth of a second,
693
00:39:09,059 --> 00:39:12,295
we take the vision
of the pale blue dot to heart,
694
00:39:12,329 --> 00:39:15,898
and learn how to share this
tiny world with each other.
695
00:39:15,933 --> 00:39:17,900
The last
internal combustion engine
696
00:39:17,935 --> 00:39:19,735
is placed in a museum,
697
00:39:19,770 --> 00:39:22,538
as the effects of climate change
reverse and diminish.
698
00:39:22,573 --> 00:39:26,409
A fifth of a second
into this future
699
00:39:26,443 --> 00:39:29,378
people will stop dying
from the effects of poverty.
700
00:39:29,413 --> 00:39:32,448
The planet is now
a completely self-sustaining,
701
00:39:32,483 --> 00:39:34,884
intercommunicating organism.
702
00:39:34,918 --> 00:39:36,953
A half-second from now,
703
00:39:36,987 --> 00:39:38,588
the polar ice caps are restored
704
00:39:38,622 --> 00:39:40,957
to the way they were
in the 19th century,
705
00:39:40,991 --> 00:39:43,926
and the forecast
is mild and pleasant
706
00:39:43,961 --> 00:39:46,229
for the next cosmic
minute and a half--
707
00:39:46,263 --> 00:39:49,298
40,000 years.
708
00:39:49,333 --> 00:39:51,467
By the time
we are ready to settle
709
00:39:51,502 --> 00:39:54,170
even the nearest
other planetary systems,
710
00:39:54,204 --> 00:39:57,006
we will have changed.
711
00:39:57,040 --> 00:39:59,776
The simple passage
of so many generations
712
00:39:59,810 --> 00:40:01,811
will have changed us.
713
00:40:01,845 --> 00:40:05,248
Necessity will have changed us.
714
00:40:05,282 --> 00:40:08,284
We are an adaptable species.
715
00:40:10,020 --> 00:40:12,421
It will not be we
who reach Alpha Centauri
716
00:40:12,456 --> 00:40:14,524
and the other
nearby star systems
717
00:40:14,558 --> 00:40:16,626
on our interstellar arks.
718
00:40:16,660 --> 00:40:19,262
It will be a species
very like us,
719
00:40:19,296 --> 00:40:22,999
but with more of our strengths
and fewer of our weaknesses;
720
00:40:23,033 --> 00:40:25,101
more confident, far-seeing,
721
00:40:25,135 --> 00:40:27,837
capable and wise.
722
00:40:27,871 --> 00:40:29,605
For all our failings,
723
00:40:29,640 --> 00:40:32,108
despite our flaws
and limitations,
724
00:40:32,142 --> 00:40:35,845
we humans are capable
of greatness.
725
00:40:35,879 --> 00:40:39,115
What new wonders,
undreamt of in our time,
726
00:40:39,149 --> 00:40:42,652
will we have accomplished
in another generation...
727
00:40:42,686 --> 00:40:44,687
and another?
728
00:40:45,923 --> 00:40:48,057
How far will
our nomadic species
729
00:40:48,092 --> 00:40:51,627
have wandered
by the end of the next century,
730
00:40:51,662 --> 00:40:54,497
and the next millennium?
731
00:40:54,531 --> 00:40:56,966
Our remote descendants,
732
00:40:57,000 --> 00:40:58,868
safely arrayed on many worlds
733
00:40:58,902 --> 00:41:01,504
throughout the solar system
and beyond,
734
00:41:01,538 --> 00:41:04,874
will be unified
by their common heritage,
735
00:41:04,908 --> 00:41:08,344
by their regard
for their home planet,
736
00:41:08,378 --> 00:41:12,048
and by their knowledge that,
whatever other life may be,
737
00:41:12,082 --> 00:41:14,851
the only humans
in all the universe
738
00:41:14,885 --> 00:41:18,020
came from Earth.
739
00:41:18,055 --> 00:41:20,022
They will gaze up
and strain to find
740
00:41:20,057 --> 00:41:22,825
the blue dot in their skies.
741
00:41:22,860 --> 00:41:25,094
They will marvel
at how vulnerable
742
00:41:25,129 --> 00:41:28,765
the repository of all
our potential once was,
743
00:41:28,799 --> 00:41:31,667
how perilous our infancy,
744
00:41:31,702 --> 00:41:35,772
how humble our beginnings,
745
00:41:35,806 --> 00:41:38,708
how many rivers
we had to cross...
746
00:41:41,645 --> 00:41:44,080
before we found our way.