All language subtitles for The.Day.the.Dinosaurs.Died.2017.1080p.WEBRip.x264-CBFM

Once upon a time,
dinosaurs ruled the world.

But 66 million years ago...

..they vanished,
virtually overnight.

So what precisely happened
in the minutes, the days, the weeks

that wiped out three-quarters
of the animal species on the planet?

Many scientists now believe
it was the impact of an asteroid

that caused their extinction.

But nobody has been able
to prove it...until now.

Evolutionary biologist Ben Garrod
and I have been granted

exclusive access to a
multi-million-pound drilling mission

into the exact point
where the asteroid hit.

This really is one of the most
impressive science laboratories

I've ever seen.

Could the team's findings
about the asteroid

finally solve the ultimate
dinosaur mystery?

This is an absolutely
amazing event -

mountains the size of the Himalayas
were formed in seconds.

With Ben at the impact site,

I will be travelling
across the world

to look for evidence of the events
that followed.

That is a bit of fossilised bone,

and they're everywhere,
scattered across this hillside.

It's just extraordinary.

Armed with astonishing
new revelations...

Right here, we have the smoking gun,
and here, we have the bodies.

..we may finally be able
to paint a picture

of the demise of the dinosaurs.

I'm off the coast of Mexico
right now

and this thing you can see behind me

is a specially adapted
drilling platform.

Now, there's an international
team of scientists on board

who are drilling far beneath
the seabed where we are now

to look for evidence to see why
and how the dinosaurs died.

This is the exact spot
of a huge asteroid strike

that happened at precisely the same
time the dinosaurs were wiped out.

This is Earth, 66 million years ago.

Here's the asteroid.

It's nine miles across -
the size of a city.

And here's the first
surprising thing -

the speed of it.

It may not look that fast
at this scale,

but it was travelling an
unbelievable 40,000 miles an hour.

Seen from the ground,

it would have gone from a mere dot
in the sky to impact

in a matter of seconds.

The asteroid smashed into
a shallow sea

north of modern-day Mexico,

exactly where the team
is starting to drill.

The theory goes that this impact
set off a chain reaction of events

that killed the dinosaurs.

But here's the heart
of the mystery...

When you compare the size
of the asteroid and the Earth,

well, the asteroid
is comparatively small.

It's like a grain of sand
hitting a bowling ball.

So how did this asteroid cause
a mass extinction

all around the globe?

By extracting rock
from the impact crater,

the team hopes to find out.

So, I'm not even strapped in,
and I don't especially like heights!

But this is great, this is great.

This multi-million-pound operation
has been decades in the planning

and we're the only film crew
to have access.

Professor Joanna Morgan
first proposed the operation.

It's been a long wait.

I've been excited for, you know,

16 years, so to actually...
For it to be happening

is quite scary.

We've had so much effort between us
to get us to this point

that...that you really want
some lovely results.

Joining her on board
to co-direct operations

is Professor Sean Gulick.

So, this is the ultimate test
of some ideas, right?

We have all these models about
how the extinction happened,

but without some samples
from ground zero,

we can't really test them.

This really is one of the most
impressive science laboratories

I've ever seen,
and it's an amazing place -

we're going to have
a quick look around.

This central area here
is incredibly important.

This is known as Main Street
by the crew and scientists.

Now, these shipping containers
are actually science labs

and, in each one...

..is a whole, entire laboratory.

You can see in here
huge amounts of equipment.

This is one of the scanning labs.

But there are still lots
of personal touches.

You can see where
all the different scientists

and the rest of the crew are from.

But my hometown's not on here!

But this is the star of the show.

This huge drill will bore through
1.5km of solid rock,

taking us back to the time
of the dinosaurs.

This is the drill bit.

Each one of these little nodules
is an industrial diamond.

We've had this one modified
with a higher-speed head

that allows us to core.

Literally collecting a column
of rock three metres at a time

and, as we go further
down the borehole,

we go further back in time,

until we actually get to
the moment of the impact,

about 66 million years ago.

As Ben joins the team
drilling down into the rock

for evidence of
the asteroid's effects,

I'm travelling the world
to look for clues from fossils.

My first stop,
1,700 miles from the crater,

is New Jersey.

I'm here to see
a mass prehistoric graveyard

unlike anything
that's been unearthed before.

This disused quarry

may be one of the most important
palaeontological sites in the world.

I'm here to view
an intriguing discovery

that may directly link
the mass extinction

to the asteroid impact.

There's something very strange
about this mass extinction.

So many animals died on that day,
and yet, it's virtually impossible

to find casualties of
this devastating event.

But palaeontologists
here in New Jersey

think they might have found
just that -

evidence of the day
the dinosaurs died.

It's such an extraordinary claim,

I want to see exactly
what they've discovered.

'I've arranged to meet
palaeontologist Kenneth Lacovara,

'one of the most experienced -

'and luckiest -
fossil hunters in the world.

'He's going to show me where
the discovery was made,

'in what used to be the seabed.'

We're going back through time.

We are. Now, if you take
one more step, Alice,

you will be in the Cretaceous.

Excellent.

'As we descend into the quarry,
we arrive at layers of sediment

'that were deposited during
the Cretaceous period,

'when dinosaurs ruled the Earth.'

So, down here,
we're in the Cretaceous period.

Here, we're in the Palaeogene
period, after the Cretaceous.

'The boundary between
the two periods marks the moment

'that the dinosaurs went extinct,
66 million years ago.'

So, this is the boundary right here.

No-one in the world has found
an in-place dinosaur fossil

one centimetre above that line.

The team uncovered a dense layer of
fossils right at this boundary line.

It's potentially a unique discovery.

Dinosaurs.

No dinosaurs.

Gosh, that's extraordinary.

'The animals found here are typical
of the late Cretaceous.'

That's a formidable-looking tooth.
It is, isn't it? Yeah.

What's that from?

This is from a mosasaur.

Mosasaur's a giant marine reptile,
an apex predator.

Think of a Komodo dragon
that's as long as a bus,

with paddles for limbs,

a two-metre jaw
packed full of these teeth.

We find mosasaurs here below
our bone bed and in the bone bed.

We never find mosasaurs
above the bone bed

because they go extinct
along with the dinosaurs.

Ken believes that the mosasaurs
he's found here

may be some of the last
that ever lived...

..and that they died as part of
the great extinction event.

To understand why,

we have to look at the other fossils
that Ken has found in the quarry.

This is incredible, Ken!

HE LAUGHS

Look at all those fossils.

25,000 of them.

SHE GASPS

The way you've laid them out in this
grid, is this as you found them?

These are the places in which
we've found them, yep.

170 square metres of them.

SHE GASPS

It's an astonishing amount of work.

All these fossils occur in a layer

that's no more than
ten centimetres thick.

'For Ken, the first clue
that these animals all died

'in a single catastrophic event

'is that the skeletons are largely
intact with no teeth marks on them.'

They weren't transported,
they weren't scavenged,

they died suddenly
and they were buried quickly.

That tells us that this is
a moment in geological time

that's days, weeks, maybe months,
but this is not thousands of years,

this is not hundreds
of thousands of years.

This is, essentially,
an instantaneous event.

'A second clue comes from
the surprising mix of species

'that had lived
in many different environments.'

I mean, I can pick out
large vertebrates.

Sure.
We see the occasional bird here.

There's a tibia from a crocodile.

And that's laying next to a piece
of the outer shell

of a huge sea turtle,

something that would be maybe
a metre-and-a-half across.

'And just a few feet away,

'Ken found another turtle from
a different part of the ocean.'

This is a coastal-living turtle.

You can see how tightly articulated
it is.

The shell doesn't flex,
so we know that this turtle

didn't dive deeply in the ocean.

This animal was living around
the coast, in the shallow water.

So, what do you think
you've got here?

All this stuff died suddenly,

and was buried all at about
the same time,

so that means all the stuff
that comes in from the coast

has to come in suddenly.

And that tells us that there is an
environmental disturbance going on

on the coastline, upshore from here.

Whatever was the cause,

this calamity that wiped out
these animals,

it was happening in the deep water,

it was happening
along the coastline,

and it's happening on land.

Ken's theory is controversial,
but if he's right,

this could be
the first fossil evidence

of a sudden mass death event
at the end of the Cretaceous...

..right at that point in time when
75% of life on Earth is wiped out.

But what caused
this mass death event?

Could all these animals have been
killed by the impact of an asteroid

1,700 miles away
in the Gulf of Mexico?

Ben is with the scientists who have
been drilling into the seabed

above the asteroid crater.

I'm here, right in the middle
of the drilling platform,

and there's a fresh core
about to come out.

We've already drilled through
500 metres of limestone sediment.

Now, we're going to start
to bring up rock core

for the scientists to examine as
we get closer to the impact crater.

This is the first full core
of the expedition,

we're excited to say.

The first full,
three-metre-long core,

some light layers.

We're wondering if they're ashes
or something.

We're pretty excited.

This, along with other core samples
like it,

can tell the team
so much information

about what was going on
at the time of the impact.

The first thing the team does
with each new core

is find out how old the rock is.

Exactly what's living,
exactly what fossils we find

tell us what age we are.

As soon as the core
comes up on deck,

we are given a small crumb
of material,

we take it back to the lab
and give an age call

within five minutes of the core
appearing on the deck.

I just got some sweet pictures.
Look at this crystal -

this is the same stuff from the core
catcher under the microscope.

Look at these crystals.

Though it contains
valuable information,

this core isn't from
the impact crater itself.

Instead, it's from the layers
of sediment above it.

The team needs to drill a further
130 metres down into the sediment

to get to the crater itself.

The further down they go,
the harder the rock is,

so that means weeks
of 24-hours-a-day drilling.

They want to pull core from an area
of the inner crater

called the peak ring,

found only in the largest
of super craters.

They're formed when the massive
impact of an asteroid

forces rock to erupt
in a central uprising,

which then collapses outwards
to form the distinctive peak ring.

It's these rocks that contain
the clues to what happened

in the moments after impact.

It's been three weeks since the team
started drilling into the seabed

and time and money
are running short.

We didn't sample that because
it's in the middle of a core.

The drill is nearly through
the hundreds of metres of limestone

that has built up since
the asteroid struck,

approaching rock layers
from the day of impact.

I mean, look at this
on the microscope.

I would say somewhere between
about 64.5 million years ago

and 63.5.

Wow.

Wow, so this was E4... Yup.
..which is 53 million.

Now we are 63,
so we have 10 million.

Yeah, that sounds like
a good estimate,

so 10 million years in three metres.
In three metres.

We've been stuck in the same zone
for a while,

going forward very slowly,
and then all of a sudden...

HE CLICKS HIS FINGERS

..boom, big jump in time.

The team are noticing clues
in the latest cores -

something extraordinary.

But as you go down, it's just more
and more and more of it.

It's got this greenish tint.

Yeah, there's one right there.

We've now had four cores
of ever-coarsening sands.

I think the only process on Earth
that can do that is a tsunami.

Tsunamis are huge, turbulent waves
that rip material from the seabed.

When the wave passes,

the material is deposited back on
the ocean floor in size order.

The heaviest, most coarse sand
settles first,

the finer sand on top.

The thicker the deposit,
the bigger the tsunami.

And the fact it's already,
like, 12 metres thick

probably already makes it
one of the largest,

maybe the largest tsunami
deposit ever discovered.

And if it keeps getting thicker
as we go, it will absolutely,

unquestionably, be the largest
tsunami deposit ever discovered.

And, of course, it's right here
in ground zero of the impact.

It's the first major clue of
how the impact of this asteroid

could have caused a deadly chain
of events,

starting with the biggest tsunami
in history.

1,700 miles away in New Jersey,

Ken Lacovara has also
picked up evidence

of what could have been a tsunami.

After that asteroid hit,
it's just chaos on the continent.

There are tsunami waves lapping up
against the continent.

You're going to have trees floating
down the estuaries.

You're going to have sediment
choking the rivers.

And that's exactly
what we see there.

Here in our fossil bed,
we get a mixture of marine organisms

and organisms that came in
from the land.

One of our more common fossils
is wood.

In the Gulf of Mexico,
the crew are on the verge

of breaking into
the asteroid impact crater,

but, at the worst possible moment,
they've hit a roadblock.

So they just woke me up
because there's

a problem with the drilling.

We don't know if it's snapped or
if it just got stuck a little bit.

We don't know, but they have
to bring it back

to the surface to take a look.

As they get nearer the crater,

the rock is getting tougher
to penetrate,

and that's causing
problems with the drill.

TOOL BUZZES

Getting to the point where you start
pushing the drill

beyond its capacity, and right now,
there's no...

There's no drilling rods, no bit,
no anything in the hole.

While the engineers fix the rig,

the scientists lose valuable
drilling time.

Behind me, you'll notice
the rig is not moving.

SPARKS CRACKLE

The pump that allows it to turn
is actually broken.

RUMBLING

We're in a bit of a race
against time now.

We're going to struggle
to get to 1,500 metres.

So we're all hopeful -

fingers, toes and so on
are crossed -

and we'll see how this goes.

Finally, after a month of drilling,

the team are pulling rock from
the asteroid crater itself.

Already, they're seeing evidence
of the incredible heat

generated by the impact -

rock that has melted.

And look at...

In this part, it is very clear that
we have different kinds of colours,

like this red colour.

It goes from green to red...

I think it's melting the material.
Melted... Yeah.

What about this?
I think that is a big cluster melt.

That does, too. Look at that.
That looks like the suevite.

And we are now fully into
impact rocks directly,

and it's really easy to see,
because it's granite,

and so you can see these spotted,
leopard-looking big chunks.

So, in effect, you know,

these were formed, you know,
on the days that the dinos died.

Quite heavy, these, aren't they?

Yeah, you really appreciate
just...just how solid this rock is.

How deep have you gone
with this so far?

We've got to just 1,330 metres,
about that.

So, we were hoping to get
1,500 metres,

but we've got 700 metres
of peak ring materials,

so we're pretty happy.

Why couldn't you get 1,500?

SHE LAUGHS

Cos...cos the budget ran out.

Oh, no!

I'm dying to ask the question
that I wanted to know as a kid -

where's the asteroid?

Yes, a lot of people think I'm going
to find the asteroid... Yeah.

..and ask me that question a lot.

Something like 95 or more percent
of the asteroid is vaporised.

Mm-hm. So, in fact, there's hardly
any asteroid here

beneath the surface.

The asteroid material
has been, sort of,

spread all around the globe,

so it's been ejected way above
the Earth's atmosphere,

travelled round the globe,
and landed around the Earth.

After eight weeks,
the work here is done.

I don't think it could have
gone much better.

I'll not forget this place.

It's been an amazing expedition,
and I expect we'll have lots more

discoveries to come.

More than 300 rock cores
have been extracted,

which the team hopes will tell
the story of how the dinosaurs died.

Four months and
over 5,000 miles later,

the rock cores are now here

at the University of Bremen
in Germany,

for the second phase

of this colossal and unparalleled
scientific journey.

I'm inside a huge fridge that's now
home to all the samples that

were taken up from
the Gulf of Mexico,

and it's really cold in here,
as you might expect.

Now, this is to stop
any organisms from growing

and contaminating these samples.

This is a test recording.
Say something.

Oh. Hello, hello.

Here in Bremen, the research team is
working to find out what happened,

minute by minute,
after the asteroid struck,

and what that meant
for the dinosaurs.

OK, this is day two that
we've had the samples,

and I'm going to take you through
the...around the labs

where everybody's started
their analyses.

Over here we can see people
looking through microscopes,

looking at thin slides that have
been collected from offshore.

Hi, Philippe. I'm going to film you
while you take a look at this core.

Hey!

Unravelling these cores
is a mammoth task.

Over 800 metres of rock
has to be carefully split,

tested and photographed.

But what they're starting to reveal
about the force of the impact

is literally earth-shattering.

This core, from above the crater,
is what typical geology looks like -

layer upon layer of
similar-looking rock,

laid down on the seabed very slowly.

This three metres of limestone took
millions of years to accumulate.

But when the asteroid struck...

..it was geology at hyperspeed.

The next 600 metres of rock
were deposited in a single day,

leaving a unique and chaotic jumble.

Sean, I mean, how do you make sense
of this incredible place

that you've got here? It is amazing.

This is 150km worth of core,

collected by the International Ocean
Discovery Programme

and all its predecessors
back to the late '60s. Mm-hm.

But from all these cores,

the most amazing is the one
we just collected... Yeah.

..in the Chicxulub impact crater.
Of course, yeah.

You can see this black,
flowing texture of the rock.

This is actually...

It looks like it flowed, right? Mm.
You can see the textures in it.

This is actually
melted basement rock,

melted granite, and it actually
takes amazing pressures to do that,

and amazing pressures
to melt the rock.

This is...

So I've got a piece of what
would be considered, sort of,

normal granite, if you will -

the kind that you might put on
your countertop,

and that's why we use it,
cos it's nice and hard.

I mean, it... Right? Pretty solid.

But this... Yeah, exactly.

This stuff has actually seen shock
of an incredible level,

so think of it as pressure waves
moving down through the granite,

like lots and lots of
little earthquakes.

And what it's done to it is,

all the way down at
the scale of a crystal,

is it's actually deformed it...
Mm-hmm.

..so that the final granite...

..can be broken.

It just crumbled up.
That's...that's amazing. Yeah.

Oh, wow. Just such incredible,
amazing forces at work here.

This whole event, it's...
I'm still finding it difficult.

Well, even as a geophysicist,
where we study this for a living,

it's really hard to wrap our brains
around the enormity of

the pressures involved,
and the enormity of the destruction

that happens in the middle of
an impact, and so quickly. Mm-hm.

This all happened
in less than ten minutes.

It's becoming clear
just how mind-bogglingly huge

the Yucatan impact really was.

And to help grasp its scale,

Sean is taking a trip to a more
recent impact site in Arizona.

This simple crater here was created
by about a 50-metre, or 150-foot,

asteroid impacting the Earth,
about 50,000 years ago.

It's about a mile across.
It's actually quite small.

It's basically, simply,
a bowl-shaped crater.

Everything above the red line
that you see there is actually

material that used to be buried
that has been flipped up on end,

and is now...or flipped upside-down,

and is now laying as a pile
of broken-up material.

By studying the shape of the crater
and the upheaval of the rock layers,

Sean, Jo and the team can
compare this site to

the Yucatan impact zone,

Even a small asteroid strike
like this

would have had
dramatic consequences.

So it comes in at something
like 26,000mph.

10km away from here, we would have
a fireball reaching,

maybe 20km away from here,
a shock wave,

and, say, 40km away from here
are hurricane-force winds,

but that would just have been
a bad day

in, today, northern Arizona.

So this is what a 50m-wide
asteroid can do -

it's devastating, but localised.

but what about an asteroid
that is nine miles across

and leaves a crater 120 miles wide?

To understand the effects
of that impact,

the team needs to know exactly
how much energy it released.

To do that, they're comparing
rock samples from Yucatan

to data gathered from some of the
largest ever man-made explosions.

This is the Nevada Test Site,

the most bombed place in the world.

The US military have detonated
904 atomic bombs here.

To help us understand how atomic
bombs connect to asteroids,

we've enlisted the help

of physicists Mark Boslough
and David Dearborn.

The blast must have come
all the way through,

and I bet these windows blew out.

Those shards of glass would be
accelerated by 90mph wind.

Wind, the windows were gone. Yes.
And they're totally...boom.

This house was part of
a test village called Survival Town,

built to study the effects
of a nuclear blast.

It actually survived a blast
called Apple-2 in May 1965.

EXPLOSION

WIND HOWLS

Most of the damage is done
by the fireball...

..and the heat that is generated,
or the blast wave as it goes by...

..and the houses that were in closer
didn't survive.

Those of us who work
on asteroid impacts,

we naturally started comparing them
to nuclear explosions.

It's a similar phenomenon.

The experimenters had
high-speed cameras,

they had gauges that measured
the intensity of the shock wave,

the blast wave in the air.

The tests found that nuclear
explosions are devastating

even at a microscopic level,

causing catastrophic shock
to minerals such as quartz.

The pressure is so high in a shock
wave from a nuclear explosion

that it actually exceeds
the strength of a crystal.

Crystal is made up of
a uniform array of atoms

and that uniformity is completely
disrupted by a strong shock wave,

and that's what shocked quartz is.

In Bremen, Professor Joanna Morgan
is looking at quartz

found in rock cores from
the asteroid impact site.

From nuclear test data,
she knows exactly how much force

it takes to shock quartz.

From this, she can tell how much
force the Yucatan rock

has been subjected to and begin to
calculate the exact amount of

energy released when
the asteroid struck.

So this is a piece of shocked quartz
that we recently drilled

from the Chicxulub impact crater.

There's lots of lines here.

Essentially, the more lines
we have on the screen,

different directions,
the more shocked this rock has been.

These are caused by the impact,

by the shock wave that travels
through this piece of quartz.

So we used exactly
the same hydrocodes, they're called,

to model nuclear explosions as we do
to model the impact craters.

We've actually stolen these codes
and applied them to our simulations

of impact crater formation.

What sort of force were
we actually talking about

from the asteroid hitting it?

This event was equivalent
to about 10 billion Hiroshimas,

so, absolutely enormous.

The most dramatic event in
the last 100 million years.

10 billion Hiroshimas combined?

That's the amount of force
going into this? Absolutely.

It's incredible, it really is.

Finally, we have hard evidence

of just how powerful
the asteroid strike really was.

10 billion Hiroshimas.

It's a major revelation.

But the truly incredible thing
about this asteroid strike

was that it changed the face
of our planet within seconds.

And now we know that,

we can do something that
has never been done before.

'Create a simulation of exactly
how the impact affected Earth

'and the dinosaurs.'

Here's what the new results tell us
about those crucial initial minutes

after the asteroid struck.

The asteroid, nine miles wide,

smashes into the Yucatan
at 40,000mph...

..vaporising instantly.

The impact makes a hole in the earth
20 miles deep and 120 miles across,

turning the surrounding sea to steam
and shattering the earth below.

Rock from deep in the Earth's crust
then rises miles into the air,

forming a tower higher
than the Himalayas

that collapses to form a strange
ring of peaks that exists today.

All this in the first ten minutes.

What did this mean
for the dinosaurs?

Well, it started an unstoppable and
devastating chain of events.

First, like an enormous nuclear
explosion,

a radiation fireball
10,000 degrees centigrade

spreads out from the impact zone.

This searing hot sphere fries
everything within

a 600-mile radius in an instant.

The truly global devastation
had its roots not in the blast,

but in the huge vapour plume

that rose out of the crater
and through the atmosphere.

A red-hot cloud of vaporised
asteroid and rock,

expanding upwards 600 miles,

spreading rapidly outwards
to fill the planet's atmosphere.

Back then, faraway New Jersey
was covered in ocean.

And it too would soon feel
the effects of the impact.

1,700 miles
from the site of the impact,

the fireball wouldn't have
been visible.

That blazing, towering,
swirling cloud

would've been just
over the horizon,

but we might have seen a faint glow.

The animals here were safe
from the direct radiation.

Two-and-a-half hours later,

like the sound of heavy traffic
in the distance,

the shock wave, now a sound wave,
arrived.

Wind starts to whip up,
growing stronger and stronger until

we're facing into
hurricane-force winds.

The blast wave from the impact

surged across the Earth
at enormous speed.

Its effects would have been
short-lived,

but those few traumatic hours

left an indelible impression
in the earth's geological record.

These are beads of molten rock
that rained down from the skies

and as they cool, they become glass.

And if you melt rock
and you cool it fast,

it doesn't have a chance to turn
back into rock, it forms glass.

Glass called spherules.

And we find these little spherules
right here

in this mass death assemblage.

What produces the kind of energy
and heat needed

to form these spherules, then?

Well, when you have
an asteroid impact,

it melts the rock and it flies up
through the atmosphere

and these bits of molten rock
rain down on the planet.

'These 66-million-year-old droplets
of molten rock show that

'debris was falling on landscapes

'far away from the impact zone
itself.'

Protected by the water,
marine creatures like the mosasaurs

may have been able to survive
these immediate events.

But for the dinosaurs on land,
with nowhere to hide,

this was the beginning of the end.

To show how the effects might
have played out

for dinosaurs on the ground,

we've enlisted palaeontologists
Steve Brusatte and Tom Williamson

to our international team.

They've come to New Mexico,

1,200 miles from the impact zone,

hunting for remains in one of
the richest dinosaur fossil sites

in the world.

Yeah. OK. Whoa.

Got a bone layer.
Look at this. Check this out.

A lot of times, we'll just be
walking around in the Badlands,

looking for stuff
that's sticking out of the rock.

That's always the first clue.

This one's really sticking out.
We can tell from the shape of it

that it's part of the backbone
of a dinosaur.

It's a bone from the backbone
of a horned dinosaur.

This is probably Pentaceratops,

which means five-horned face,

two brow horns, a nasal horn
and then a cheek horn on each side.

Triceratops has three horns
on its face.

This guy had two more horns,
so five horns total,

so an even gaudier dinosaur.

The ceratopsians, like Pentaceratops
and Triceratops,

were a large group of plant-eating
dinosaurs

that roamed the American landscape

for the 20 million years
leading up to the asteroid impact.

There it is. Pretty good.
Look at that. Not bad.

This whole area here,

honestly, it's littered with
these kind of bones.

These were the cows
of the Cretaceous,

they would've been everywhere
on this landscape.

66 million years ago, this area
would've looked very different.

Today, it's known as
the San Juan Badlands.

Back then, it wasn't so bad at all.

This whole area was a lush jungle.

Dense vegetation.

Thick forests cut through
by flowing rivers.

When that day started, this whole
area here would've been teeming

with dinosaurs, and then,
about 2,000km or so,

1,200 miles in this direction
to the south-east, the asteroid hit.

And very quickly, the dinosaurs
would've realised

that something was wrong,

because there would've been
an enormous red glowing cloud

that would've filled up
much of the sky here.

The glowing cloud
would've looked dramatic,

but this far from the impact zone,

the dinosaurs here would've
been safe...for now.

Now, their cousins down in Texas,

about 1,000 kilometres closer
to the impact site,

they were toast.

They were incinerated,
they were vaporised.

By studying the Yucatan rock core,

we know the exact timing
of what happened next.

11 minutes after the impact,

the vapour cloud arrived
in New Mexico.

The skies darkened
and the temperature started to rise.

It wasn't really a case of fire
and brimstone

raining down from the heavens.

It was more a case of all of that
stuff heating up the atmosphere

and turning the atmosphere
into a giant radiator.

The heat was so intense that,

over 1,000 miles away
from the impact,

many animals would have been
roasted alive.

Climate specialist Dr Brian Toon

is the first scientist ever
to theorise what happened next.

A devastating global firestorm
he's studied for more than 20 years.

It wasn't falling on you,
it was 60km above the ground or so,

and the glowing hot lava was
emitting an amount of energy

that's a few times larger
than the sun.

This is not a normal fire.

The fire was started everywhere,
which causes what's called

a mass fire.

Mass fires can be much hotter
than a normal fire.

Well, the leaves on the ground
caught fire,

leaves in the trees caught fire...

The underbrush caught fire.

There's winds at hurricane speeds
rushing into the fire,

drawing upward into
the rising flames

and they consume everything.

And this vapour quickly spread
across the planet.

Probably only took a few hours

for it to reach the furthest
reaches of the Earth.

Thanks to our new model of
what happened after the impact,

we now know that fires spread
right around the globe.

But were these fires devastating
enough to cause the extinction

of all of the world's dinosaurs
in a single day?

'To find out, I'm travelling far
from the impact site

'to the very tip of South America

'and the remote wilderness
of Patagonia.'

Over 4,000 miles away
from where the asteroid hit.

I am all the way down here in Chile.

Now, we tend to think
of this asteroid

as being absolutely enormous,
and it was - 14km in diameter -

but in the context of the size
of the Earth,

that's like a grain of sand
impacting on a bowling ball.

And I want to understand
what kind of impact

the asteroid landing here
had on the dinosaurs

right down here at the toe
of South America.

Leading the hunt for clues
is palaeontologist Marcelo Leppe.

He's taking me to look
for dinosaur remains

in a mountain valley
that's best accessed on four legs.

Marcelo, can you explain to me how
the geology of this valley works?

Actually, we are passing
through time

and we are moving to the end
of the Cretaceous,

to the end of the age
of the dinosaurs.

We are, at the moment,
in 80 million years ago,

this is Campanian.

So this is fantastic.

As we ride along the valley,
as we ride north,

we're riding from 80 million
to 66 million years.

Through time.

Getting closer
to that extinction event.

We've reached
the Valley of the Dinosaurs.

Now I want to see what sort of
dinosaurs lived here and find out

what happened to them in
the hours after the impact.

So, shall we get off and
have a look?

Yeah, let's leave the horses
and look. Seems like a good idea.

The place is literally
full of bones.

As you can see,
this sunlight is the best

because the angular light
is reflecting the bones.

Let's see if we can find a dinosaur,
then. Yeah, let's...let's see.

Oh, for example, there.

Or here.

Look, just beside you.

This, here?
Yes, this is a dinosaur bone.

Oh. That's fantastic.

They're different colour.
Greyish, or white.

Yeah, so what's that, then?

Oh, it looks like a vertebrae.

Probably the first one.

OK, so...yeah.

That looks like a facet, it looks
like the surface of a joint

and that would be
where the skull sits.

Any ideas what species?

Yeah, probably a hadrosaur. 99%.
Really? Yeah.

That's your first hadrosaur, yeah?
Yeah, it is.

'This valley is now a bone bed,
four miles long.'

Yes, that is a bit of fossilised
bone and they're everywhere.

Scattered across this hillside.

It's just extraordinary.

Once, it was home to herds
of hadrosaurs.

Plant-eaters up to 30-feet long
with a distinctive duck-billed face.

But did the dinosaurs
down in Patagonia

die on the day the asteroid hit?

Thanks to the team in Bremen,

we now know that once the asteroid
struck the Yucatan Peninsula

over 4,000 miles away,

it took 42 minutes for
the superheated cloud of debris

to reach Patagonia.

For much of the planet,

the fires triggered
by the burning sky

led to total destruction.

But Marcelo has found evidence

that that may not have been
the story here.

Plants that the hadrosaurs
used to eat.

This is Nothofagus,
the southern beech.

They're all around here,
aren't they?

And if you want to see it,
look at that architecture.

And I want to show you
also this one.

This is from Las Chinas,

the same valley we were looking
for the hadrosaurs.

Oh, this is fantastic.

This is what the hadrosaurs
were walking on. Yeah.

And if you want to compare it...
Well, that looks incredibly similar.

Is there actually a relationship

between this fossil leaf
and this living one?

Oh, there is a direct line

from this fossil and this one that
is living today in Patagonia.

So this is fantastic evidence that,
down here in Patagonia,

some spaces did actually
make it through.

66 million years ago,
this region was warm, wet

and dense with vegetation
like the southern beech.

A species of plant that survived
the fires on impact day.

And if plants survived,

maybe the dinosaurs here
could have done, too.

Life down here should
have been badly hit,

but the fossil evidence,
particularly of plant life,

is telling us a different story -

that the immediate fallout
from Chicxulub

in Patagonia
was not as bad as predicted.

So perhaps our hadrosaurs
had a stay of execution,

maybe they made it through
that first day.

But something...

Something got them in the end.

To determine exactly what did happen
in the days, weeks and months

after the asteroid struck,
the Bremen team are still

hard at work studying rock samples
from the impact crater.

Dr Philippe Claeys thinks he's found
perhaps the most important clue yet.

So, Philippe,
when this asteroid struck Earth,

it had a massive
and devastating impact.

But that didn't quite seal the fate
of the dinosaurs, did it?

Probably not. Remember,
the dinosaurs were ideally adapted

to the late Cretaceous environment.

They were the ultimate animal
for the Cretaceous.

What happened here is that

we have an incredible change
in the Earth's system,

basically kills the dinosaur
everywhere on Earth -

in Africa, Antarctica,
in the forests, or in the savanna.

But what made them extinct?

You talk about a global scale,
suddenly.

What went global? What happened?
What went global is really

the ejection of material
from the crater.

Look at what I have in my pocket -
this is gypsum. Right, OK.

This was part of Yucatan
at the time of impact. Yeah. OK?

And this material here
contains sulphate.

And this gypsum affects
the chemistry of the atmosphere.

It changes it drastically.

This area's meant to be rich
in this sort of stuff.

It's supposed to be full of it.
But it's not.

We can look for the remnants
of it here.

In the core, it's totally absent,

which means that almost
the entire sequence of gypsum

that was present
in the sedimentary target

at the time of impact
went into the atmosphere.

This is a huge discovery.

The presence of gypsum means
the plume of vaporised rock

that spread across the world
was dense with sulphates

that blocked sunlight.

The same thing happened after
the 1991 eruption of Mount Pinatubo

in the Philippines.

Sulphates reduced the amount
of sunlight reaching land by 10%,

which caused a drop
in global temperatures.

25 years ago, Pinatubo had an
incredible effect on the atmosphere.

It cooled it by very little,
but it had an effect.

And it stayed for a couple of years.
Right.

Here, we have an event which is
orders of magnitude more important.

Pinatubo is nothing compared
to the Chicxulub impact.

It is really going global,
no place is protected,

no dinosaur can escape

the consequence of
the Chicxulub impact.

This is the gypsum.

This is what killed
the dinosaurs. Wow.

This astonishing find is
the final piece of the jigsaw...

..allowing us, for the first time,

to model what finally
killed the dinosaurs.

It's what happened in the days
after the impact

that made it a global extinction.

Our blue planet turned grey.

Long after the hot skies cooled,
ash and dust in the atmosphere

almost completely
blocked out the sun.

As the lights went out,
global temperatures plunged

more than ten degrees centigrade
within days.

This is where we get to
the great irony of the story.

Because in the end, it wasn't
the size of the asteroid...

..the scale of the blast,

or even its global reach
that made dinosaurs extinct.

It was where the impact happened.

Had the asteroid struck
a few moments earlier,

or maybe even a couple of seconds
later,

then rather than hitting
shallow coastal waters,

it might have hit deep ocean.

An impact in the nearby
Atlantic or Pacific oceans

would have meant much less
vaporised rock,

including the deadly gypsum.

The cloud would have been less dense

and sunlight could have still
reached the planet's surface...

..meaning what happened next
might have been avoided.

In this cold, dark world,

food ran out in the oceans
within a week,

and shortly after, on land also.

With nothing to eat
anywhere on the planet,

the mighty dinosaurs stood
little chance of survival.

In Patagonia, 10% of plant species
went extinct.

The southern beeches would have
shed their leaves,

shutting down for the long winter
that the asteroid set off.

The hadrosaurs were left to starve.

The demise of the dinosaurs
down here in Patagonia

was nowhere near as dramatic as
being obliterated by a blast wave,

or drowned in a tsunami,

or even being caught up
in a colossal forest fire.

But they were doomed, nonetheless.

The dinosaurs as a group were
hugely successful and diverse,

they'd been on the planet for
more than 150 million years.

But this Chicxulub event was more
than just a local phenomenon.

It changed the climate globally,

plunging the world
into a deep, deep winter.

And there was no time to adapt.

So, in some ways,

the dinosaurs that died
instantaneously were the lucky ones.

This sudden climate change may
finally solve the mystery of

what happened in New Jersey.

As the food supply
in the oceans dwindled,

shallow water creatures
roamed ever deeper.

But eventually,
the food would run out.

And all of those animals from
different parts of the oceans died,

coming to rest in a single layer.

It's been an incredible adventure
decades in the planning.

A multi-million-pound
scientific expedition,

weeks of drilling rock samples
from deep inside a super crater,

and months of studying hundreds
of metres of rock samples.

So, this was E4. Yep.
Which is 53 million to 55.

We were just jazzed about
the science, all day long.

Many people have been up
for 20 hours

and they were still just going
with enthusiasm,

describing the cores,
looking at the microfossils.

It was a heady experience.

All that hard work
has paid off in a big way.

The team has been able to reveal
extraordinary new details,

evidence about
how the dinosaurs died.

But perhaps even astonishing than
what killed the dinosaurs...

..is what happened
after they were gone.

The asteroid and its aftermath
ended the age of the dinosaurs.

But as the cloud started to clear,
months or years later,

the dormant plants came back to
life.

And a tiny group of animals came out
of hiding to inherit the Earth.

Creatures that would,
over millions of years,

evolve into a huge range
of different species...

Including us.

On the tip of my finger right here

is a lower tooth of something
called mesodma.

This was a little guy who was
probably about the size of a mouse.

This is one tough little mammal.

One of the very few species
known to survive

through the global devastation.

It's a blade-like tooth.

It was able to feed on things like
insects and seeds,

so it didn't have to rely on
photosynthesis.

Mammals had lived in the shadow of
the dinosaurs for 100 million years.

But now it was their turn.

This chance event that was the doom
of the dinosaurs

was a stroke of luck for
the surviving mammals.

With the dinosaurs gone,

suddenly, the landscape
was empty of competitors

and ripe with possibilities.

Just half a million years after
the extinction of the dinosaurs,

and landscapes around the globe
had filled up with mammals

of all shapes and sizes.

Fast forward another
60 million years or so,

and we have the evolution of
an extraordinary upright walking ape

that contemplates its own existence

and the demise of ancient creatures
they'd never even seen.

Chances are,
if it wasn't for that asteroid,

we wouldn't be here
to tell the story today.