Transcript
00:00
ah
00:16
as far as we know it's the only home to
00:19
life in the universe
00:22
why what is it that makes our planet so
00:27
special the answers are hidden deep in
00:31
the Earth's past to find them we must
00:35
travel back in time to see the first
00:38
humans walk the earth
00:40
to ride continents on a collision course
00:43
face killer dinosaurs dive into oceans
00:51
full of bizarre life-forms
00:56
feel the bitter chill of global ice ages
01:02
and experience the fury of cosmic
01:05
missile attacks we must travel back in
01:09
time until we reach the birth of the
01:12
earth itself then we can piece together
01:15
our planets incredible story and
01:19
discover why all of this all of us are
01:24
here
01:41
our journey starts almost 5 billion
01:44
years ago but this can't be right
01:49
there's no sign of our beautiful blue
01:51
planet just a newborn star our Sun
01:58
surrounded by all this dust
02:03
we've arrived too early before the earth
02:07
has even formed
02:20
speed up time and we can see gravity
02:24
pull the dust into tiny rocks it hardly
02:29
seems possible but something as complex
02:33
as a planet is made from nothing more
02:36
than dust and rocks
02:43
over millions of years gravity pulls
02:46
these rocks together to form the earth
02:51
one of at least a hundred planets
02:54
circling the Sun
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but 4.5 4 billion years ago our planet
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looks more like hell than home
03:42
up close the temperature is over 1,200
03:45
degrees Celsius
03:49
there's no air just carbon dioxide
03:52
nitrogen and water vapor
03:59
it's so hot so toxic that if we got any
04:04
closer we'd be incinerated and
04:05
suffocated in seconds
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the newborn planet is a boiling ball of
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liquid rock there are virtually no solid
04:19
surfaces just an endless ocean of lava
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a young planet called Theia is heading
04:40
straight for us
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it's the size of Mars and it's traveling
04:47
at nearly 15 kilometers a second 20
04:50
times faster than a bullet
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the intruders gravity is distorting the
05:06
Earth's surface
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the blastwave
05:34
races out around the planet
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it's as though both young planets turn
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to liquid trillions of tons of debris
05:46
blast out into space
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but over the course of just a thousand
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years gravity works its magic and turns
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the rubble into a ring of red-hot dust
06:20
and rock that circles the earth
06:27
and now from this ring of all forms over
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3,000 kilometers wide
06:42
we're watching the birth of our Moon
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it's much closer than the moon we
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recognize just 22,000 kilometers away
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instead of about four hundred thousand
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kilometers
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the Sun rises over a cooling earth
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and sets just three hours after advisors
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the impact has set the earth spinning so
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fast that an entire day lasts just six
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hours the days may pass quickly but the
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earth changes slowly to understand the
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making of our planet we need to fast
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forward through millions of years
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a hail of meteors
08:37
3.9 billion years ago and we're under
08:40
attack from debris left over from the
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solar system's formation
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look at these strange crystals inside
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the meteors
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they look like grains of salt the same
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salt you'd put on your french fries and
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inside these minut droplets of water
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it seems these deadly missiles could
09:19
contain the vital ingredient for life on
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earth
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there's only a small amount of water
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inside each meteorite but as they
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bombard the earth for over 20 million
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years pools of water grow the water
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collects on solid ground
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the Earth's core remains montón but its
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surface is cool too around 70 or 80
09:59
degrees just enough to form a crust in
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the future we could swallow this water
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when we take a drink
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every sip every puddle every drop of
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water in every ocean is billions of
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years old
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and it may have traveled millions of
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kilometers to reach us carried inside a
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meteor
10:31
the earth looks more familiar but this
10:34
is still a dangerous place
10:41
this wind is as fast perhaps faster than
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the most destructive hurricane
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it's a mega storm ripped up by the
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planets rapid rotation
10:57
the moon is so close to Earth that it's
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gravity is overwhelming it creates huge
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tides that race across the planet's
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surface
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but over time the moon moves away the
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waves calm and the planet spins slower
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700 million years after the planets
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birth life-giving water covers its
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surface
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but not just water
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there's something else down there
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tiny islands they seem to have appeared
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from nowhere
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until molten rock bursts through the
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Earth's crust and rises up through the
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ocean
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over time the lava cools and forms a
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volcanic island
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this is how these islands formed
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in the future they will join together to
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form the first continents
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the infant earth has water and land it's
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beginning to look like the planet we
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call home but the atmosphere is toxic
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and the temperature is scorching
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nothing could live here
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meteors
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they've been raining down since the
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planets formation but now 3.8 billion
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years ago the assault has entered a
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violent new phase
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something has disturbed the orbits of
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these meteorites
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they already brought water to the planet
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but they're carrying something else too
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as the meteorites dissolve they release
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their minerals and transport carbon and
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primitive proteins amino acids from
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outer space to the bottom of the ocean
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it's dark the sun's rays can't reach
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beyond 300 meters and it's close to
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freezing
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this must be a mirage
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a city of underwater chimneys
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it's not smoke it's some kind of hot
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liquid
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see water has seeped down into the earth
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through cracks in the crust getting
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hotter collecting minerals and gases on
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the way
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it's this potent mixture that's spewing
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back out into the ocean building these
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towers
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add to this all those minerals and
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chemicals from the meteorites and the
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water has become a chemical soup
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it's impossible to know how or when but
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somehow these chemicals have come
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together to create life the water is now
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full of microscopic organisms these
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single-celled bacteria are the earliest
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forms of life on Earth
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this is a defining moment in the making
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of the planet
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microscopic life is underway
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to find more complex life we need to
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travel forwards through time to 3.5
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billion years ago and a shallow ocean
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these look like rocks or even plants
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they seem to grow out of the seabed
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each is a mountain of living bacteria
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colony called a stromatolite
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as if by magic these bacteria turns
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sunlight into food this process called
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photosynthesis
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uses the power of sunlight to transform
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carbon dioxide and water into glucose a
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simple form of sugar and similar to the
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stuff we put in our coffee
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and this magical transformation releases
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a byproduct a gas called oxygen
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underwater the stromatolites
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slowly fill the oceans with oxygen
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the oxygen turns traces of iron in the
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water into rust
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this falls to the ocean floor to form
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deposits of iron rich rock
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one day we'll use this mineral to build
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bridges ships and skyscrapers
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above the waves the oxygen transforms
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the atmosphere these stromatolites are
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creating a single most important element
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for life on Earth
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without them virtually every living
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thing wouldn't exist
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when we take our next breath we're doing
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it thanks to these colonies of ancient
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bacteria
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over the next two billion years oxygen
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levels continue to rise
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and as the planet spins slows the days
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get longer
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now they last at least 16 hours we're
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discovering it takes a long time to make
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a planet 1.5 billion years ago three
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billion years after the planets birth
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and there's no complex life no plants no
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dinosaurs no humans but the earth has
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something that no other planet has a
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force with the power to change
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everything
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our planet a beautiful blue ball dotted
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with volcanic islands one and a half
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billion years ago
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it's home to primitive life
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over millions of years we can see
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something is rearranging the islands
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hidden beneath the ocean the Earth's
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crust has broken into vast plates deeper
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still the Earth's cores at work it's
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hotter than the surface of the Sun so
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hot it generates movement in the rock
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beneath the crust these movements push
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and pull the plates around the globe and
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carry the oceans and the islands with
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them millions of years raced by seeing
20:45
it like this our planet seems active
20:48
changing alive over 400 million years a
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vast new supercontinent takes shape
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called Rodinia
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in the shallow waters around rodinia
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stromatolites have been working their
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magic for over two billion years pumping
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oxygen into the atmosphere the
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temperature is 30 degrees Celsius and
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the days are 18 hours long
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but this looks more like Mars than earth
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to find life here we need to move on
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through time
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the state of Washington
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750 million years ago some forts from
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deep inside the planet itself is ripping
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the crust to pieces it's as though the
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world is tearing apart
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and there's only one force powerful
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enough to do this
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heat it escapes from the Earth's molten
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core stretching and weakening the crust
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centimeter by centimeter year by year
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the great supercontinent is splitting in
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two
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the intense geological activity has
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spawned a mass of volcanoes these pump
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carbon dioxide into the atmosphere
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there's smoke and gas everywhere
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all that carbon dioxide mixes with water
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to make acid rain
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the rocks absorb the acid rain including
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its carbon dioxide and there are a lot
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of rocks on the earth right now exposed
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when the continent tore apart
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so many that vast quantities of carbon
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dioxide are absorbed out of the
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atmosphere and locked up in the Earth's
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rocks
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there's not enough carbon dioxide in the
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atmosphere to trap the sun's heat around
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the planet
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in just a few thousand years the
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temperature plummets to around minus 50
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degrees
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this frozen wasteland is southern
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Australia
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650 million years ago
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it's the start of what some scientists
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call snowball earth a period they
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believed to be the longest coldest ice
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age ever to grip the planet
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a vast wall of ice thousands of meters
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high
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the ice is unstoppable
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the more ice there is the more sunlight
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it reflects away from the planet and the
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faster the ice spreads
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and there's a second ice sheet just as
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high
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the two sheets spread away from the
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poles towards each other to meet at the
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equator
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now an ice sheet up to three kilometers
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thick in Tunes the entire planet
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first the planet was a molten ball of
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fire now it's a frozen ball of ice
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virtually all the sun's light and warmth
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reflects back into space
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but it can't last forever something must
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release the earth from this frozen
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prison and when it does who knows
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whether life will have survived beneath
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the ice the surface is frozen but the
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core is still hotter than the sun's
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surface
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volcanoes have been erupting since the
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world began to freeze but up until now
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even their heat and power made no impact
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on the ice
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volcanoes pump out billions of tons of
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carbon dioxide before the big freeze the
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Earth's rocks absorb most of the co2 but
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now with the rocks smothered in ice
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there's nothing to absorb the gas so it
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fills the atmosphere
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like a blanket it traps the sun's warmth
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around the planet temperatures rise
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until now after 15 million years the ice
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begins to melt
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it's thought that during snowball earth
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the ice pushed the cross down now as it
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melts the cross bounces up
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this creates fissures and weak spots and
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more and more volcanoes
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these volcanoes release more carbon
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dioxide and push the temperature up even
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higher
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the melt gathers momentum
29:15
oxygen levels rocket
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through a series of chemical reactions
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the ice has created oxygen
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while the planet was frozen the sun's
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ultraviolet rays reacted with water
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molecules in the ice to produce a
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chemical rich in oxygen
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hydrogen peroxide
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the same chemical that bleaches head
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now as the ice melts the hydrogen
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peroxide breaks down and releases
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massive amounts of oxygen
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the earth is waking up and it's a very
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different place
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now 600 million years ago the atmosphere
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is warmer it feels like a summers day
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and the days are about 22 hours long
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add all this water and it's the perfect
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recipe for life
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before snowball earth primitive bacteria
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had emerged in the oceans but surely
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they couldn't have survived an ice age
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75 times longer than the entire span of
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human history if something has survived
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then our best chance of finding it is
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where we last saw life in the ocean
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now 540 million years ago in an ocean
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full of oxygen those primitive bacteria
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have evolved a handful must have clung
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on through the big freeze there are
32:26
clients everywhere
32:29
and something else
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it looks like some kind of armored slug
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it's called we wax eeeh it's one of a
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new generation of complex multi-celled
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organisms
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we're entering one of the most dynamic
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periods in the earth story the Cambrian
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explosion
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increased oxygen levels allow creatures
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to grow larger and develop bony
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skeletons
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there are worms
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sponges and these
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they're trilobite distant relatives of
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insects lobsters even scorpions
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life in the oceans is blossoming
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from microscopic bacteria to a monster
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like this this is an ama lak Eris it's
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about 60 centimeters long
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look at its large eyes its razor-sharp
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teeth and grasping limbs
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all anomalocaris has to do is take it
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speak
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the trilobite guard right itself it's
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soft belly is exposed
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these are pic aiya they're just five or
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so centimetres long but they've got what
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may be the first ever spine over
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millions of years this simple structure
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will evolve into the spine that keeps us
35:19
standing erect and creatures are
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beginning to take on familiar forms
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beneath the waves there are already tens
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of thousands of plant and animal species
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the advance of life seems unstoppable
35:51
we're looking to life on land
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460 million years ago and the plates
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have moved again below lies a new
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continent Gondwana
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it's a warm 30 degrees Celsius oxygen
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levels are close to those in which we
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live the land should be covered with
36:18
plants crawling with creatures
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but there's not much here beside a few
36:27
patches of algae
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there's only one explanation
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the son
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it blasts the surface with deadly
36:51
radiation
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the complex life we've seen in the ocean
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doesn't stand a chance on land
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but 50 kilometers are where the rays
37:08
enter the Earth's atmosphere
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something strange is happening when
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oxygen meets the sun's radiation the
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oxygen turns into another kind of gas
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called ozone this gas forms a blanket
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around the planet this ozone layer
37:27
absorbs the lethal radiation
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over 120 million years the ozone layer
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gets thicker and stops more and more
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radiation from reaching the Earth's
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surface without this layer life on land
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simply wouldn't exist
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now shielded from radiation life
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blossoms
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those small mossy lumps are the first
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land plants and they're pumping out even
38:08
more oxygen levels saw
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375 million years ago
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there's something down there in the
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water it's moving swimming
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it's a strange fish called a Tiktaalik
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you
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it's neck allows it to raise itself up
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it uses its fins as if their legs
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and moves out of the water where Clarke
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life is exploding
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over 15 million years these creatures
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call tetrapods evolve they grow stronger
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limbs and spend more time out of the
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water until 360 million years ago they
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make the land their home
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it's from a creature like this that all
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four-legged vertebrates will evolve
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dinosaurs birds mammals and eventually
40:29
you need
40:40
we've come a long way from a lump of
40:43
burning rock and dust to a Bluegreen
40:47
planet bursting with life
40:54
there are still no humans but there are
40:58
fish plants and this
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it's a dragonfly a dragonfly the size of
41:10
an eagle
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this giant is called meganula
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what were once legs have evolved into
41:22
wings extending the dragonflies hunting
41:25
territory over a vast area
41:33
there are millipedes spiders all sorts
41:37
of bugs down there
41:40
these creatures called arthropods were
41:43
among the very first to set foot on land
41:46
they've already been around for hundreds
41:49
of millions of years they look almost
41:52
identical to the bugs that invade our
41:54
homes today except for one big
41:57
difference like mega Noura they're
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monsters
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we've stumbled into a lost world of
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giants where millipedes are two meters
42:12
long and scorpions the size of wolves
42:17
all the oxygen in the atmosphere allows
42:19
their respiratory systems to be more
42:21
efficient and frees up space for their
42:24
bodies to grow
42:27
a lizard-like creature called anonymous
42:34
the creatures we've seen so far laid
42:37
their eggs in the water
42:43
but these eggs contain all the water and
42:46
nutrients the developing Heil anima
42:48
Sneed's the babies are growing in their
42:52
own self-contained pond
43:00
the egg is a major evolutionary
43:03
breakthrough
43:08
now animals can leave the water behind
43:11
and conquer the land
43:21
this baby hi Lana mas will lead the
43:24
advance
43:27
it's a new kind of creature a reptile
43:48
inevitably with life comes death there's
43:53
so much dead plant matter it builds up
43:55
and decays into dense soggy layers
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over hundreds of millions of years rocks
44:04
will cover these layers heat from the
44:08
Earth's core and pressure from the
44:10
overlying rocks will transform the
44:13
layers of dead plants into seams of coal
44:18
each lump of coal we burn today to warm
44:21
our homes and fire our power stations is
44:24
made of flowers that died 300 million
44:27
years ago
44:35
amidst the decay hidden from sight life
44:39
is stirring
44:41
soon seeds will germinate plants will
44:45
grow and this wasteland will live again
44:50
life seems to have conquered the planet
45:20
a herd of creatures graze the Siberian
45:23
Plains they're not dinosaurs
45:26
they won't set foot on earth for at
45:28
least another 20 million years but
45:32
they're big evolution has taken a huge
45:36
leap forwards the small lizards we saw
45:39
earlier and now giant reptiles
45:44
these are scooter soars the distant
45:48
relatives of turtles they're plant
45:54
eaters and if the plant eaters look this
45:57
tough the karlik wars must be seriously
46:00
mean it's a Gorgon awesome
46:08
a perfectly engineered prehistoric
46:11
killing machine
46:22
the gorgonopsids saber teeth have
46:25
wounded the scooter sir
46:41
the predator is watching as its prey
46:45
grows weak from blood loss until hold on
46:57
it's backing off something strange is
47:01
happening
47:03
the ground is getting hot
47:06
you
47:12
there must be enormous pressure beneath
47:15
the surface
47:43
there's larvae but this isn't one single
47:47
volcano the entire landscape is erupting
47:54
it's a flood basalt eruption a massive
47:59
plume of mantle is rising up from deep
48:01
inside the earth pushing molten rock out
48:04
through fissures in the Earth's crust
48:15
the lush paradise is now a lifeless hell
48:20
the SCOOTER sores and the gorgonopsids a
48:23
debt they're the first casualties in the
48:27
greatest mass extinction the world has
48:29
ever seen the Permian extinction
48:43
on the other side of the continent of
48:46
Gondwana it's as if nothing happened
48:59
snow
49:02
but the temperature is about 20 degrees
49:04
Celsius
49:07
it's not snow it's ash fallout from the
49:11
eruption some 16,000 kilometers away
49:19
the ash burns suffocates and kills
49:23
animals around the world
49:36
the atmosphere is full of sulfur dioxide
49:38
from the eruptions and it rains the gas
49:42
turns to sulfuric acid and burns
49:45
everything it falls on
49:52
at first it seemed like this was a local
49:55
disaster but now it's gone global
50:02
the Siberian eruptions increase the
50:05
Earth's carbon dioxide levels
50:12
the atmosphere gets hotter
50:15
water evaporates
50:19
the vegetation dies
50:23
we saw life had finally found a foothold
50:32
now it looks like we were wrong
50:45
there are no signs of life on land but
50:49
in the oceans
50:52
this can't be right the oceans are
50:56
turning pink
51:04
and the plants the trilobites
51:07
the Predators everything's gone
51:10
everything except for this pink algae
51:14
the new hotter atmosphere must have
51:17
heated the oceans and stripped them of
51:18
oxygen
51:21
now nothing except algae can survive in
51:25
the stagnant water
51:29
the Siberian eruptions are transforming
51:32
the entire planet
51:34
nothing not even the deepest ocean floor
51:38
is beyond their reach
51:42
look bubbles
51:49
but it's not oxygen it's methane
51:52
escaping from vast pockets of methane
51:54
gas beneath the seabed methane is a
51:59
greenhouse gas at least 20 times
52:02
deadlier than carbon dioxide
52:06
until now the gas has been frozen but as
52:09
the sea temperature rises the gas begins
52:12
to melt
52:28
released into the atmosphere this
52:30
powerful gas pushes up temperatures even
52:32
further
52:35
up to almost 40 degrees six degrees
52:39
hotter than before the Siberian
52:41
eruptions
52:47
now even the creatures that have made it
52:50
this far are tuned
52:56
it's 500,000 years since the eruptions
52:59
first began and all this time for half a
53:03
million years the lava has been pouring
53:06
out by now it covers an area the size of
53:10
the United States with a layer of molten
53:13
rock nearly six kilometers deep 250
53:20
million years ago we're back where we
53:22
started on a lifeless planet
53:27
almost it's 50 million years since
53:37
virtually all life on Earth was wiped
53:40
out and the planet has been transformed
53:48
it's now 200 million years ago and
53:52
there's just one supercontinent called
53:55
Pangea stretching from pole to pole
54:13
after the trauma of the mass extinction
54:16
the planet is healing
54:20
temperatures are stabilizing the acid
54:23
rain is neutralizing and vegetation
54:25
returning
54:39
and with 95% of all life on Earth wiped
54:43
out the field is open for a new species
54:46
to emerge one that will dominate the
54:50
planet like no other before or since
54:59
the dinosaurs
55:05
these dinosaurs are called Amazon's like
55:09
all dinosaurs they've evolved from the
55:11
handful of reptiles that survived the
55:13
Permian extinction
55:18
at four and a half meters tall their
55:21
size makes them slow and vulnerable I
55:28
don't offer Soros two of them they're
55:40
small and fast
55:45
you
56:10
the Allosaurus is too big a meal for one
56:13
Dilophosaurus but not for too
56:31
the dinosaurs have repopulated the earth
56:35
but no species contain this Restless
56:39
volatile planet
56:47
the Earth's crust is thinning here it's
56:50
releasing lava shaking with earthquakes
56:53
as though it's been stretched by some
56:55
unseen force
57:02
and the same thing is happening all the
57:04
way down what will be North America's
57:06
eastern seaboard
57:16
the Earth's plates are on the move again
57:20
190 million years ago the great
57:23
supercontinent of Pangaea breaks up
57:31
a vast slab of land has broken away you
57:35
creates a chasm and this fills with a
57:38
new ocean called the Texas over what
57:41
will one day be the Middle East
57:45
currents are pushing nutrients up into
57:47
the coastal waters running along what
57:49
will be Saudi Arabia Iraq and Iran
57:56
and the nutrients attract fish in their
57:59
Millions
58:04
and with so much life also comes death
58:11
dead fish and plankton carpet the ocean
58:13
floor
58:20
over the next 10 million years layers of
58:24
rock will bury and heat the dead
58:26
creatures ancient fish and plankton will
58:32
become oil
58:42
every litre of fuel in our cars every
58:48
piece of plastic on the planet the paint
58:51
on our walls the carpet under our feet
58:54
even the soap you wash with almost all
58:58
originated in this way
59:19
180 million years ago and further west
59:23
the North American plate is still moving
59:25
away from the European and Asian plate
59:31
it happens slowly at about two and a
59:35
half centimeters each year the same
59:37
speed as our fingernails grow
59:41
but hit fast-forward and a new ocean
59:44
forms right beneath us and new
59:48
continents
59:51
Montreal moves away from Marrakesh New
59:54
York from West Africa
59:57
the world as we know it is taking shape
60:00
the chasm between the two continents
60:03
fills to create a vast ocean
60:07
the Atlantic
60:16
and they're in the middle a volcano
60:21
we've seen plates move before we know
60:25
it's caused by currents deep beneath the
60:27
earth's crust this process is happening
60:30
down there right now
60:47
the entire seafloor has been torn in two
60:50
and pushed up into a ridge of mountains
60:53
and volcanoes it's growing higher than
60:57
the Himalayas and longer than the
60:59
Rockies
61:02
the waters hot here molten lava is
61:06
forcing its way out from deep inside the
61:08
earth
61:13
as the lava cools it's creating a new
61:16
range of volcanic mountains and new
61:19
ocean floor
61:22
this is what's pushing the plates and
61:24
Pangaea apart
61:27
and rearranging our world
61:45
it's this geological activity that makes
61:48
the earth Restless creative unique
61:56
and every time the planet reinvents
61:58
itself the things that live on it must
62:01
adapt and evolve
62:11
things like these there akia sores
62:18
they're reptile ancestors lived on land
62:21
but as the planet changed so did they
62:24
they grew fins and moved into the newly
62:27
formed Atlantic Ocean
62:34
this one is six meters long and fast it
62:38
travels at about forty kilometres an
62:39
hour
62:46
it's the oceans fastest creature the
62:50
most efficient predator and it's ruled
62:53
the Earth's oceans for 50 million years
63:11
but now there's a new contender for the
63:14
crown
63:29
appliance or
63:33
longer than a bus as heavy as a truck
63:37
its jaws are immense over eight times
63:41
more powerful than a great white sharks
63:43
and its teeth a 30 centimeters long
64:01
the earth and the creatures that live on
64:03
it has changed beyond recognition
64:07
this was once solid ground now it's the
64:11
Atlantic Ocean
64:13
it was on this very spot that we stood
64:16
and watched
64:17
Amazon's graze and I'll office or stalk
64:20
their prey the dinosaurs world may be
64:24
different but there is dominant as ever
64:28
they appear invincible
64:46
it's a shrew-like mammal and it's
64:50
evolved from the small number of mammals
64:52
that survived the mass extinction 185
64:54
million years ago it's also prey for the
64:58
dinosaurs this is why most mammals live
65:02
in the trees or underground and venture
65:05
out at night mammals are no threat to
65:08
the dinosaurs
65:16
nothing on earth can challenge their
65:18
dominance
65:25
nothing on earth
65:38
it's a lump of space rock a large one
65:49
this asteroid is about ten kilometers
65:51
across bigger than Mount Everest
66:03
and it's traveling at over 70,000
66:06
kilometers an hour straight towards the
66:09
earth
66:20
it's heading for the Gulf of Mexico just
66:24
off the Yucatan Peninsula
66:35
it travels so fast blink and we'd miss
66:38
the impact unless we slow down time it's
66:46
a split second that will change the
66:48
world forever
66:56
at the moment of impact the asteroids
66:59
back edge is still nearly 11,000 meters
67:03
the same height as a commercial aircraft
67:05
flies
67:21
the asteroid strikes with such immense
67:25
force it destroys everything it hits
67:30
even the asteroid itself instantly
67:33
vaporizes
67:43
the impact unleashes the energy of
67:45
millions of nuclear weapons
67:59
nowhere is safe not even way up here
68:06
some of these boulders are as big as
68:09
entire city blocks
68:29
the blastwave races out from the impact
68:32
zone like shrapnel from an exploding
68:34
bomb
69:12
I mean it's after impact thousands of
69:14
kilometers from where the asteroid
69:16
struck the earth is under attack from
69:19
every direction
69:24
boulders rained down
69:31
earthquakes shake the ground
69:38
and tsunamis batter the coasts
69:54
but the onslaught has only just begun
69:58
the plume of molten rock and dust
70:01
spreads out and engulfs the planet
70:06
the entire sky is acting like a giant
70:09
sunlit
70:17
the Earth's surface heats up to 275
70:21
degrees vegetation begins to
70:26
spontaneously ignite
70:36
even months after the impact smoke and
70:39
ash still block out the sun's rays
70:43
with less sunlight plants died and the
70:47
animals that eat them starve
70:52
against this onslaught it's hard to see
70:55
how anything can survive the dinosaurs
71:01
165 million year reign is over
71:13
but the dinosaurs demise is an
71:17
opportunity for another species mammals
71:22
by living underground they've avoided
71:25
the heat in the fires and by eating
71:28
anything and everything they thrive
71:31
while more selective eaters die
71:42
these are the unlikely inheritors of the
71:45
dinosaurs crown
71:54
and as one story ends another begins
72:02
with the dinosaurs out of the way this
72:06
could be our ancestors chance the
72:14
dinosaurs are long dead the planet is
72:17
peaceful
72:24
in this new world our mammal ancestors
72:26
are evolving
72:39
this lake 47 million years ago in what
72:43
will one day be Germany should be the
72:45
perfect place to spot them
73:04
this isn't like the mammals we saw
73:06
earlier its eyes and brain are bigger
73:10
this is Darwinian massive a or EDA she
73:17
looks nothing like us but fossil
73:19
evidence from our own time tells us
73:21
these creatures could evolve into
73:23
monkeys apes and eventually humans
73:31
we're looking back through 47 million
73:33
years of evolution to what may be one of
73:37
our earliest known ancestors
73:43
the lake sits on a volcanic crater it
73:47
belches out noxious gas
73:58
now the lake that killed her will
74:01
preserve her in its oxygen-depleted
74:04
deaths
74:15
one day when the water has gone an EDA
74:19
is fossilized in stone we will discover
74:25
her and recognize in this primitive
74:28
primate what could be the very beginning
74:31
of our own story the story of human life
74:51
we're closer to understanding how
74:53
everything we've seen from ocean
74:55
bacteria through walking fish and
74:58
subterranean rodents leads to us and to
75:03
understanding how our planet was made
75:14
47 million years ago and the atmosphere
75:18
is much like our own
75:23
the temperature is 24 degrees Celsius
75:27
and a day lasts just under 24 hours the
75:33
earth we're looking at now is almost
75:35
identical to the planet we call home
75:38
almost
76:00
the Earth's plates have been on the move
76:01
again with the continents on their backs
76:06
India moves north towards Asia
76:18
the Indian and Asian plates are locked
76:21
in a titanic struggle
76:24
you
76:31
neither plate is winning both plates
76:35
begin to buckle
76:38
what was once oh she and floor contorts
76:41
upwards along a two and a half thousand
76:43
kilometer line
76:52
a vast mountain range rises up
76:56
1,500 meters 4,500 meters
77:06
now over 8,000 meters
77:13
you
77:17
these are the Himalayas
77:29
and there it is the highest mountain of
77:33
all
77:34
Mount Everest
77:41
when the snow on the peaks melts it
77:44
feeds great rivers the Ganges Indus
77:49
Yangtze and yellow rivers
77:57
the Himalayas are like a vast water
77:59
tower one day their rivers will supply
78:03
water for almost half the world's
78:05
population
78:22
20 million years ago this is our planet
78:27
with every continent every ocean just as
78:32
we know it
78:34
except there's one thing missing us the
78:39
human race
78:42
for humans to evolve something somewhere
78:46
down there has to change
79:08
along Africa's East Coast between the
79:11
plates that make up the Earth's crust a
79:13
great rift opens up
79:21
the rift stretches nearly 6,000
79:24
kilometers
79:30
along its edge mountains grow
79:41
there
79:44
it looks like a name not a human it
79:48
might stay in these trees forever but
79:51
its world is changing
79:59
the growing mountains act like a wall
80:02
they stop moisture from the Indian Ocean
80:05
passing over the land it's getting
80:09
hotter and drier the lush rainforest is
80:13
becoming arid savanna
80:18
the new hotter climate destroys the
80:20
creatures habitat
80:27
it forces them to search further afield
80:30
for food to stop dragging their knuckles
80:33
on the floor like Apes to stand and walk
80:40
on two feet it's the most important step
80:43
in the human story
80:48
this mountain range along Africa's East
80:51
Coast could be the reason we walk on two
80:54
feet it seems incredible the random
80:58
movement of two plates may have
81:00
kick-started a chain of events that will
81:03
lead to the first humans
81:32
the man and child it could be a scene
81:37
from our own time but it's one and a
81:41
half million years ago these are an
81:44
early species of human called Homo
81:47
erectus
81:51
and these are the first footprints like
81:53
our own civilizations past and present
81:58
everyone that's ever lived the greatest
82:01
inventions the most brilliant ideas
82:04
human history in all its complexity and
82:08
splendour begins here and now
82:31
the climate changes again 70,000 years
82:37
ago sea levels fall the gap between
82:40
Africa and Arabia shrinks down to just
82:43
13 kilometers the Red Sea is narrow and
82:49
shallow enough for this small group to
82:52
cross out of Africa
82:57
they're another later species of human
83:01
called Homo sapiens
83:16
they've made it across scientists
83:21
believe every man woman and child
83:22
outside of Africa is descended from
83:25
these 200 or so individuals over time
83:32
our ancestors multiply and spread out to
83:35
India on to Asia and into Europe
83:47
but while humans head north a giant wall
83:50
of ice travels south
84:04
Europe 40,000 years ago our Homo sapiens
84:11
ancestors are arriving only to find a
84:14
world that's changing fast it's getting
84:18
colder it should be the height of summer
84:20
but the plants are frostbitten the
84:24
rivers are frozen
84:32
natural changes in the Earth's orbit co2
84:37
levels and the flow of warm water around
84:39
the planet conspire to lower the earth's
84:42
temperature
84:44
the earth and its inhabitants enter an
84:48
ice age
84:50
Glacia is as high as skyscrapers creep
84:53
over the northern hemisphere at 30
84:54
centimeters a day
84:57
slow and powerful they sculpt the
85:00
landscape as they move over it
85:02
gouging out great depressions
85:06
the planet will never look the same
85:08
again
85:16
now around 20,000 years ago they grind
85:20
to a halt
85:22
much of the Northern Hemisphere is
85:24
covered by ice sheets up to two and a
85:26
half kilometers thick with trillions of
85:30
gallons of water locked up as ice sea
85:33
levels fall
85:45
twenty thousand years ago a strip of
85:48
land emerges from the ocean between
85:50
Siberia and Alaska
85:56
it's a bridge between two vast
85:59
continents a gateway that takes humans
86:03
from Asia to a new world America it's
86:09
the last great continent to be colonized
86:11
the last great human migration and
86:15
somewhere down there are the first
86:18
Americans
86:33
now 14,000 years ago the changes that
86:37
triggered the ice age go into reverse as
86:41
the ice retreats it reveals a very
86:43
different northern hemisphere the
86:47
glaciers gouged out huge depressions now
86:50
they fill with water to become North
86:53
America's Great Lakes
87:08
6,000 years ago the ice retreats back to
87:13
the poles to the Arctic and Antarctic
87:40
after a four and a half billion year
87:43
dirty we've made it we're back home this
87:49
is our world our time now for the first
87:55
time we can piece together our planet's
87:57
incredible story we can understand how
88:01
and why everything we see around us is
88:04
here today from the skies above us to
88:13
water the essential ingredient for life
88:20
the ground beneath our feet
88:27
and finally life
88:32
the spectacular result of a chain of
88:35
catastrophes and coincidences
88:42
each triumph each disaster is a step on
88:47
the trail that leads to here
88:51
to each and every one of us right now
88:57
the earth story doesn't end here
89:03
a lot has happened but there's more to
89:07
come
89:10
the earth will live for at least another
89:12
four and a half billion years everything
89:18
we've seen on our journey is only half
89:20
the story
89:25
just imagine what wonders what terrors
89:29
what strange creatures lie ahead for our
89:32
Restless creative planet
89:40
the next chapter of Earth's story is
89:44
still to be written
89:49
take another epic voyage in journey
89:51
through the Milky Way brand-new next
89:53
Sunday at 7:00
89:54
stay tuned for 2012 the final prophecy
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