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(dramatic music)
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Earth is born out of chaos and catastrophe.
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(planets crashing)
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Despite such hostile conditions, life emerges on our planet.
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But it must withstand deadly disasters, again and again.
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(wave crashing)
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Planet Earth is a wild world,
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shaken by unimaginable impacts,
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volcanic eruptions that flood the landscape
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and drastic climate changes that lead to ice ages
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that freeze the world from pole to pole.
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(dramatic music)
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Yet each assault creates a path for something new.
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Life always finds a way
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despite being constantly put to the test.
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Without these catastrophes, life as we know it
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would not exist on our fateful planet.
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(dramatic music)
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(birds chirping)
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During the Cretaceous period about 66 million years ago,
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our closest ancestors are small mammals.
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For them, earth is a terrifying place,
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one fraught with danger and constant peril
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because this is a world ruled by terrifying creatures.
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(dinosaurs growling)
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The dinosaurs.
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(dinosaurs growling)
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They dominated earth undisputed
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for more than 150 million years
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until a catastrophe ended their reign.
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A disaster so enormous,
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it not only wiped out most of the dinosaurs,
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but 75% of all species on our planet.
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(fire raging)
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Scientists have been investigating the cataclysm for decades
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to determine what caused this mass extinction.
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There are various theories.
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The one states that an asteroid impact is responsible.
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(dramatic music)
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(asteroid exploding)
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Armed with the latest technology,
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experts are trying to unravel the mysterious circumstances
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behind the fateful event that changed our planet forever.
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(dramatic music)
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Lance Creek, Wyoming.
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(car engine revving)
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(dramatic music)
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Paleontologist Philipe Havlik, has come here to investigate
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how the world of the dinosaurs came to a sudden end.
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(dramatic music)
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He is visiting an excavation site
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filled with fossils of dinosaurs
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that lived at the end of the Cretaceous period,
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just before the disaster struck.
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(footsteps crunching)
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[Philipe Voiceover] The Lance Creek area is one of the
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most important historic dinosaur areas in the world.
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It was, especially at the beginning of 20th century
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when there was a lot of dinosaur hunters in this area.
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It's a place where you find plenty of dinosaur bones
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in one spot.
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It's a bone bed, let's say a layer,
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which is really kind of built up by dinosaurs.
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The rocks here reveal the ancient landscape
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that was home to the last dinosaurs.
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Observing the geology of the Lance Formation
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like this sandstone, like this layering and so on,
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we can see it was a big river system.
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There was a lot of water about 70 million years ago
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in this spot.
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So this means it was kind of
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the perfect place to live for dinosaurs.
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And this is what we have today,
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almost at every spot you go,
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we will find some isolated bones at least.
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It's kind of magic.
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This was home to some of earth's
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most iconic dinosaurs.
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One sports, two massive horns on its huge head
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and a third smaller horn on its nose.
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Its Greek name triceratops,
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means three horn face.
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The beast roams the plains feeding on vegetation
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and smashing down taller plants by using its horns,
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beak and sheer bulk.
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But the mighty triceratops has an even larger neighbor,
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one that can easily eat the three horn beast for lunch,
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the T-Rex.
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The king of dinosaurs is on the hunt.
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At nearly 42 feet long, this bipedal carnivore
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is one of the largest predators to ever live on land.
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Boasting the strongest bite of all terrestrial animals,
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this apex predator inspires fear.
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(dramatic music)
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(footsteps thudding)
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(dramatic music)
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(dinosaurs growling)
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This triceratops is lucky.
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(dinosaurs growling)
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The T-Rex realizes it is too dangerous to try for a meal.
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(dinosaurs growling)
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(dramatic music)
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(footsteps thudding)
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In the dust layered rocks. Havlik is searching for clues
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about gigantic battles like these fought eons ago.
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It's not long before he finds the first interesting fossil.
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This is a vertebrae of a dinosaur,
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actually of a duck-billed dinosaur of an edmontosaurus.
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A pretty small one.
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I think it's somewhere from the tate.
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Edmontosaurus is a bulky herbivore beast
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reaching 42 feet in size.
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It has a long flattened tail and became known
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as a duck-billed dinosaur because of its unique horny beak,
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perfect for smashing tough plants.
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Huge herds of edmontosaurus graze on this landscape
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and are much safer prey for a hungry T-Rex.
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(dramatic music)
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(birds chirping)
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(dramatic music)
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The entire area is rich with fossils
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that can reveal the fate of the dinosaurs
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at the end of the Cretaceous.
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But to uncover the secret behind their demise
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and that of 75% of all species on earth,
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Havlik's team comes up with an unusual idea.
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(dramatic music)
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So we wanted to get this absolutely unique bone bed,
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which is like that much of bones
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over a surface of several square miles.
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You should imagine how much this will be in bones, yeah.
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We want to take off a piece of about a five to five meters
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to uncover it totally to clean the surface,
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to fix anything we could find.
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We wanted to dig it out
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on the highest precision ever possible
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and then to take it into pieces with a chain saw
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and transporting it about 8,000 kilometers
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from Wyoming to Frankfurt, Germany.
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Two containers weighing a total of 30 tons
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were shipped by boat.
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The scientists hope the bone bed will reveal new details
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about what life was like
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just before the dinosaurs went extinct.
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Frankfurt, Germany, the dinosaur bone bed
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from the Lance Formation has arrived
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in the Senckenberg Museum for Natural History.
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Professor Andreas Mulch is the director
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of the Senckenberg Research Institute.
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He's hoping this bone bed will help him figure out
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what the world was like just before the catastrophe struck.
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(speaks in foreign language)
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In any good detective novel,
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the detective looks for the killer
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by investigating the crime scene.
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We're actually doing the same thing here.
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We want to understand what conditions
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the edmontosaurus lived in,
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what was the climate like, what was the vegetation like?
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So to understand how life an
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therefore the disappearance of the dinosaurs took place.
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At the end of the Cretaceous period.
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(speaks in foreign language)
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Professor Mulch and his colleagues
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recover many fossils from the bone bed,
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including teeth from the edmontosaurus.
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(speaks in foreign language)
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Take a look at this tooth pattern.
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They belong together?
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Yes, they belong together.
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Then the teeth just kept moving forward little by little.
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And this is the occlusal surface.
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These teeth were all hidden in the jaw.
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and then it grows out of the jaw.
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Yes, there were just lots of rows
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next to each other.
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Clues hidden within the tooth enamel
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will reveal more about the world
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in which the dinosaurs lived.
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(machine humming)
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(dramatic music)
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When we analyze the tooth enamel
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of this edmontosaurus we get a snapshot
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of the environmental conditions during the Cretaceous period
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just before the dinosaurs went extinct.
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While the isotope analyses do not allow us
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to directly measure temperature and climatic conditions,
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they do give us an insight into the conditions
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that prevailed at that time.
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We get a fingerprint of the climate
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and vegetation conditions
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and this allows us to reconstruct quite amazing things.
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(speaks in foreign language)
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By analyzing isotopes preserved
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within the dinosaurs tooth enamel,
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Mulch discovers what the edmontosaurus ate
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66 million years ago.
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(speaks in foreign language)
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Here we can see from the carbon isotopes
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that edmontosaurus fed on plants that grew
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in dried up lakes or salt marshes.
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So they give us a special insight into the entire ecosystem.
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(speaks in foreign language)
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This allows the scientists
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to reimagine the environment where the edmontosaurus lived
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at the end of the Cretaceous.
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Along with carbon isotopes, oxygen isotopes
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give further insight into the paleo environment.
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(speaks in foreign language)
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Oxygen isotopes give us information
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about the development of precipitation
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and temperature at the earth's surface.
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From the variation of oxygen isotopes within the teeth,
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we can see how the temperature has changed
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over the course of the year,
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and we can see here that winter temperatures
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must have been significantly warmer than they are today.
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Everything indicates that we have annual temperatures
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that were up to 14 degrees Fahrenheit warmer.
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In other words, a whole lot warmer.
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(speaks in foreign language)
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This happened because of a significant rise
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in carbon dioxide.
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What we know today from all the data
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is that the Cretaceous was basically a time
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of high atmospheric CO2 concentration.
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The last time CO2 levels soared
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was at the end of the Permian period
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where unprecedented volcanic eruptions
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triggered the largest mass extinction on earth.
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Where the changes seen in the Cretaceous atmosphere
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also extreme enough to end the reign of the dinosaurs?
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(speaks in foreign language)
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Unlike the rise in temperature
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at the Permian Triassic boundary
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or the climate change we are experiencing today,
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climate change during the Cretaceous
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took place over many millions of years.
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So ecosystems and also species had time to adapt.
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Long-lasting climate changes are thus much easier
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for ecosystems to withstand
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and can give rise to entirely new species
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and species communities.
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The bone bed reveals that many species
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benefited from the gradual increase in CO2.
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(speaks in foreign language)
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That's a really nice little section
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of the bone bed with an impressive variety of species on it.
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From predatory dinosaurs to edmontosaurus teeth
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and pieces of a turtle.
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(speaks in foreign language)
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We find plant remains, mammals, fish,
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everything that lived in and around the river.
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It is therefore clear that this great diversity
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also brought with it a diverse ecosystem.
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The high level of CO2 stimulates evolution
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for the majority of species.
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Dinosaurs in particular thrive in this new environment
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since their metabolism functions much better
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in warmer climates.
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We can definitely say
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that the high temperatures and the high CO2 concentration
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at the end of the Cretaceous
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were not the killer of the dinosaurs.
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66 million years ago, the concentration of CO2
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is high and so is the biodiversity.
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Life is thriving in a warming tropical world,
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but things are about to change.
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The rain of the dinosaurs is about to end
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along with three quarters of all life on the planet.
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00:13:24,240 --> 00:13:29,223
Only this time a changing atmosphere won't be to blame.
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Something even more deadly and immediate
273
00:13:33,660 --> 00:13:35,493
is just around the corner.
274
00:13:36,490 --> 00:13:40,140
(dramatic music)
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South Dakota in the Hell Creek Formation,
276
00:13:43,560 --> 00:13:45,780
one of the world's leading dino hunters
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00:13:45,780 --> 00:13:49,353
is looking for the remains of the ancient catastrophe.
278
00:13:52,080 --> 00:13:55,830
Peter Larson has discovered many fossils in the area
279
00:13:55,830 --> 00:13:58,503
that date to the extinction of the dinosaurs.
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00:13:59,340 --> 00:14:02,880
So about 66 million years ago,
281
00:14:02,880 --> 00:14:05,557
this looked a whole lot different than it does today.
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(dramatic music)
283
00:14:06,690 --> 00:14:10,260
Our fateful planet is constantly changing
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00:14:10,260 --> 00:14:13,564
as its tectonic plates reshape the surface.
285
00:14:13,564 --> 00:14:15,300
(dramatic music)
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During the Cretaceous, north America is slowly shifting
287
00:14:18,960 --> 00:14:21,679
into the geography we know today.
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00:14:21,679 --> 00:14:22,590
(dramatic music)
289
00:14:22,590 --> 00:14:24,990
The area around the Hell Creek Formation
290
00:14:24,990 --> 00:14:28,500
was a low-lying floodplain consisting of rivers,
291
00:14:28,500 --> 00:14:30,810
streams, and wetlands.
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It's the land of the dinosaurs
293
00:14:33,600 --> 00:14:36,366
where countless species roam freely.
294
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(dramatic music)
295
00:14:38,250 --> 00:14:41,400
So if we were here 66 million years ago,
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you'd probably see often the distance,
297
00:14:43,890 --> 00:14:47,100
a giant herd of of duck-billed dinosaurs,
298
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maybe as many as 10 to 20,000 of 'em in one group,
299
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out just basically foraging
300
00:14:51,900 --> 00:14:53,670
and getting as much food as they can.
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00:14:53,670 --> 00:14:55,680
Maybe you'd see an isolated triceratops
302
00:14:55,680 --> 00:14:58,530
or maybe a family group over in here.
303
00:14:58,530 --> 00:15:00,510
And then somewhere in the taller trees,
304
00:15:00,510 --> 00:15:02,100
maybe there's a T-Rex kinda waiting
305
00:15:02,100 --> 00:15:03,903
for its opportunity to strike.
306
00:15:06,090 --> 00:15:08,640
Larson's picture of the Cretaceous world
307
00:15:08,640 --> 00:15:12,483
is based on decades of work by many paleontologists.
308
00:15:13,770 --> 00:15:17,310
Every new discovery provides another clue
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00:15:17,310 --> 00:15:19,890
about the creatures that lived here.
310
00:15:19,890 --> 00:15:22,020
This is cool.
311
00:15:22,020 --> 00:15:24,900
It isn't long before the veteran dino hunter
312
00:15:24,900 --> 00:15:27,330
uncovers a new piece of the puzzle.
313
00:15:27,330 --> 00:15:29,190
We've got a couple of ribs,
314
00:15:29,190 --> 00:15:31,350
or maybe the same rib just broken.
315
00:15:31,350 --> 00:15:34,773
And this cervical vertebra of a triceratops.
316
00:15:36,180 --> 00:15:38,712
A bone broken in this way means a larger
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00:15:38,712 --> 00:15:41,820
and stronger dinosaur was involved,
318
00:15:41,820 --> 00:15:45,003
likely a T-Rex hoping for dinner.
319
00:15:46,680 --> 00:15:49,320
This triceratops was probably killed by a T-Rex.
320
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It's almost positive it was eaten by a T-Rex
321
00:15:51,960 --> 00:15:54,880
and it was actually one of the last dinosaurs to live
322
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These fossils paint a vivid picture
323
00:15:58,020 --> 00:16:01,734
of life here 66 million years ago.
324
00:16:01,734 --> 00:16:02,640
(dinosaur growling)
325
00:16:02,640 --> 00:16:04,980
But then the story ends.
326
00:16:04,980 --> 00:16:07,770
Just somewhere above us, there's a line in the sand
327
00:16:07,770 --> 00:16:09,423
that the dinosaurs never crossed.
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00:16:10,620 --> 00:16:12,780
To an untrained eye,
329
00:16:12,780 --> 00:16:17,085
this change in the rocks is nearly invisible.
330
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(dramatic music)
331
00:16:19,560 --> 00:16:22,605
But its significance is huge.
332
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(dramatic music)
333
00:16:25,710 --> 00:16:29,430
So this is the line in the sand
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00:16:29,430 --> 00:16:31,920
that the dinosaurs never crossed.
335
00:16:31,920 --> 00:16:34,890
And it was for a long time people looked at this
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00:16:34,890 --> 00:16:36,840
because there's no dinosaur bones above it,
337
00:16:36,840 --> 00:16:38,250
but there's dinosaur bones below it,
338
00:16:38,250 --> 00:16:40,500
all the time we find dinosaur bones below it.
339
00:16:41,400 --> 00:16:45,420
This line is known as the K-Pg Boundary.
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00:16:45,420 --> 00:16:48,810
It represents the end of the Cretaceous period
341
00:16:48,810 --> 00:16:51,660
and the end of the dinosaurs.
342
00:16:51,660 --> 00:16:56,660
This clay layer was deposited literally worldwide
343
00:16:57,270 --> 00:16:59,400
from some event.
344
00:16:59,400 --> 00:17:04,290
And there's, fellas by the name of Walter and Louis Alvarez
345
00:17:04,290 --> 00:17:06,990
who were tracing this clay layer and they found it
346
00:17:06,990 --> 00:17:09,150
in Italy and they found it in Denmark.
347
00:17:09,150 --> 00:17:11,160
And basically wherever we had marine sediment
348
00:17:11,160 --> 00:17:15,153
that preserves that moment in time, they find this clay.
349
00:17:15,990 --> 00:17:18,150
This boundary marks exactly
350
00:17:18,150 --> 00:17:20,700
when one of the greatest mass extinctions
351
00:17:20,700 --> 00:17:22,323
took place on earth.
352
00:17:23,340 --> 00:17:26,280
Radiometric dating reveals that the layer
353
00:17:26,280 --> 00:17:28,743
is 66 million-years-old.
354
00:17:29,580 --> 00:17:33,000
But scientists are still trying to solve the mystery
355
00:17:33,000 --> 00:17:34,950
of how and why it happened.
356
00:17:34,950 --> 00:17:37,800
This discovery of this boundary clay and what it means
357
00:17:37,800 --> 00:17:40,290
is super important to our understanding
358
00:17:40,290 --> 00:17:42,120
of how the dinosaurs died.
359
00:17:42,120 --> 00:17:44,460
It's about two centimeters thick,
360
00:17:44,460 --> 00:17:48,840
it's a layer of clay and it's high in the element iridium.
361
00:17:48,840 --> 00:17:50,370
Iridium is a rare earth element,
362
00:17:50,370 --> 00:17:52,980
which means it's very rarely found on earth,
363
00:17:52,980 --> 00:17:56,220
but it is common in asteroids and meteorites.
364
00:17:56,220 --> 00:17:58,500
Just after our planet formed,
365
00:17:58,500 --> 00:18:01,140
meteorite strikes were common,
366
00:18:01,140 --> 00:18:05,430
but as billions of years passed, most dangerous space debris
367
00:18:05,430 --> 00:18:08,010
was cleared from the solar system.
368
00:18:08,010 --> 00:18:11,443
Still the threat of a major impact remained.
369
00:18:11,443 --> 00:18:12,360
(dramatic music)
370
00:18:12,360 --> 00:18:15,510
And so they came up with a hypothesis
371
00:18:15,510 --> 00:18:18,240
that the this clay layer was formed
372
00:18:18,240 --> 00:18:21,300
by the collision of an asteroid with the earth.
373
00:18:21,300 --> 00:18:23,850
And with the amount of iridium they theorized
374
00:18:23,850 --> 00:18:26,280
that this asteroid would've had to have been
375
00:18:26,280 --> 00:18:27,420
somewhere between,
376
00:18:27,420 --> 00:18:30,270
or somewhere around 10 kilometers in diameter
377
00:18:30,270 --> 00:18:32,250
in order to deposit this much iridium
378
00:18:32,250 --> 00:18:34,470
in that small amount of time.
379
00:18:34,470 --> 00:18:37,140
And so, but there was no crater.
380
00:18:37,140 --> 00:18:40,650
Nobody knew of a crater that was that time or that size.
381
00:18:40,650 --> 00:18:44,010
Because that would mean it was a a 300 kilometer crater
382
00:18:44,010 --> 00:18:47,553
that this 10 kilometer wide asteroid would've created.
383
00:18:47,553 --> 00:18:48,450
(dramatic music)
384
00:18:48,450 --> 00:18:51,630
This killer asteroid theory is popular
385
00:18:51,630 --> 00:18:54,090
in the scientific community,
386
00:18:54,090 --> 00:18:57,240
but the crime scene remains elusive.
387
00:18:57,240 --> 00:18:58,607
Where did it strike?
388
00:18:58,607 --> 00:19:01,440
(dramatic music)
389
00:19:02,430 --> 00:19:04,650
The Barringer Crater in Arizona
390
00:19:04,650 --> 00:19:07,113
is one of the most famous craters on earth.
391
00:19:08,460 --> 00:19:10,650
It was formed by a meteorite
392
00:19:10,650 --> 00:19:12,240
that struck the earth's surface
393
00:19:12,240 --> 00:19:15,243
approximately 50,000 years ago.
394
00:19:16,260 --> 00:19:18,210
The meteorite is estimated
395
00:19:18,210 --> 00:19:21,603
to have been around 160 feet in diameter.
396
00:19:22,440 --> 00:19:26,130
The impactor that may have caused the dinosaurs to vanish
397
00:19:26,130 --> 00:19:29,640
is believed to be far larger.
398
00:19:29,640 --> 00:19:34,260
So the same must be true for the crater it created.
399
00:19:34,260 --> 00:19:38,340
But such a massive crater dating from the late Cretaceous
400
00:19:38,340 --> 00:19:41,550
had not been found anywhere on land.
401
00:19:41,550 --> 00:19:44,580
So scientists turned their search to the sea,
402
00:19:44,580 --> 00:19:47,897
perhaps the crater was hidden beneath the waves.
403
00:19:47,897 --> 00:19:49,680
(dramatic music)
404
00:19:49,680 --> 00:19:53,760
During the 1970s Mexican oil company, Pemex,
405
00:19:53,760 --> 00:19:56,673
was scouting the sea floor in the Gulf of Mexico.
406
00:19:57,570 --> 00:19:59,550
They didn't find oil,
407
00:19:59,550 --> 00:20:02,490
but near the Yucatan town of Chicxulub,
408
00:20:02,490 --> 00:20:04,830
they did discover strange rocks
409
00:20:04,830 --> 00:20:06,813
that hit it at something else.
410
00:20:08,049 --> 00:20:11,040
(dramatic music)
411
00:20:11,040 --> 00:20:14,730
Professor Ulrich Riller, at the University of Hamburg
412
00:20:14,730 --> 00:20:17,343
analyzes maps of the area.
413
00:20:18,590 --> 00:20:19,860
(speaks in foreign language)
414
00:20:19,860 --> 00:20:22,380
The map shows a gigantic ring structure
415
00:20:22,380 --> 00:20:24,960
that is located at a depth of more than half a mile
416
00:20:24,960 --> 00:20:27,300
below the Earth's current surface.
417
00:20:27,300 --> 00:20:29,970
It extends to a depth of 12 miles
418
00:20:29,970 --> 00:20:32,924
with a diameter of about 120 miles.
419
00:20:32,924 --> 00:20:35,190
(speaks in foreign language)
420
00:20:35,190 --> 00:20:37,020
It is a huge pattern
421
00:20:37,020 --> 00:20:41,190
that has all the characteristics of an impact crater.
422
00:20:41,190 --> 00:20:43,500
Could this be the site?
423
00:20:43,500 --> 00:20:45,840
Half of the crater is submerged.
424
00:20:45,840 --> 00:20:49,803
So the scientist searching for the other half on land.
425
00:20:50,798 --> 00:20:52,080
(dramatic music)
426
00:20:52,080 --> 00:20:57,080
Mexico, a series of mysterious sinkholes dot the landscape.
427
00:20:57,721 --> 00:21:00,150
(dramatic music)
428
00:21:00,150 --> 00:21:04,290
These holes known as cenotes appear randomly
429
00:21:04,290 --> 00:21:06,693
across the vast Yucatan Peninsula.
430
00:21:08,490 --> 00:21:12,750
No rivers or lakes exist in this part of the Yucatan.
431
00:21:12,750 --> 00:21:15,990
So villages sprang up around many of the cenotes
432
00:21:15,990 --> 00:21:18,411
that filled with fresh water.
433
00:21:18,411 --> 00:21:21,244
(dramatic music)
434
00:21:22,114 --> 00:21:25,410
Professor Riller believes the fascinating cenotes
435
00:21:25,410 --> 00:21:29,531
may hold clues to what happened here eons ago.
436
00:21:29,531 --> 00:21:32,961
(dramatic music)
437
00:21:32,961 --> 00:21:34,170
(speaks in foreign language)
438
00:21:34,170 --> 00:21:36,990
Since the 1990s, there has been a suggestion
439
00:21:36,990 --> 00:21:41,160
that the cenotes could be related to an asteroid impact.
440
00:21:41,160 --> 00:21:43,950
NASA had mapped the water holes at that time
441
00:21:43,950 --> 00:21:46,893
and found that many of them are circularly arranged.
442
00:21:48,390 --> 00:21:51,690
However, a plausible explanation for this observation
443
00:21:51,690 --> 00:21:53,805
was not offered at the time.
444
00:21:53,805 --> 00:21:57,555
(speaks in foreign language)
445
00:21:58,923 --> 00:21:59,910
(dramatic music)
446
00:21:59,910 --> 00:22:01,890
Thousands of small dots
447
00:22:01,890 --> 00:22:04,920
show where the cenotes are located.
448
00:22:04,920 --> 00:22:08,493
A large part of them lies on a perfect semicircle.
449
00:22:09,899 --> 00:22:10,732
(speaks in foreign language)
450
00:22:10,732 --> 00:22:13,500
NASA experts suspected that this formation
451
00:22:13,500 --> 00:22:16,473
could represent the southern part of the crater ring.
452
00:22:17,670 --> 00:22:19,170
The underwater formation
453
00:22:19,170 --> 00:22:23,673
matches the ring of cenotes perfectly, except for one hitch.
454
00:22:24,516 --> 00:22:25,680
(speaks in foreign language)
455
00:22:25,680 --> 00:22:28,350
But the hypothesis had a problem.
456
00:22:28,350 --> 00:22:32,705
The rock in which the cenotes are located is much younger.
457
00:22:32,705 --> 00:22:34,089
(dramatic music)
458
00:22:34,089 --> 00:22:35,640
Ulrich Riller thinks
459
00:22:35,640 --> 00:22:39,360
the cenotes may have formed because of the impact crater,
460
00:22:39,360 --> 00:22:41,490
but more recently.
461
00:22:41,490 --> 00:22:44,310
To test his theory, he prepares an experiment
462
00:22:44,310 --> 00:22:47,820
with his PhD student, Jan-Oliver Heisman.
463
00:22:47,820 --> 00:22:50,010
They want to simulate how an impact crater
464
00:22:50,010 --> 00:22:51,960
might affect the surrounding sediment
465
00:22:51,960 --> 00:22:54,480
over a long period of time.
466
00:22:54,480 --> 00:22:57,270
The scientists pour a mixture of sand and flour
467
00:22:57,270 --> 00:23:01,740
over a layer of silicon, which simulates the earth's crust.
468
00:23:01,740 --> 00:23:04,440
A rotating blade produces a crater,
469
00:23:04,440 --> 00:23:07,953
then they check how this affects the surface over time.
470
00:23:09,000 --> 00:23:11,613
Time lapse records, any movement.
471
00:23:12,810 --> 00:23:15,300
The crater depression is partially leveled
472
00:23:15,300 --> 00:23:17,943
by the silicon substrate over time.
473
00:23:19,328 --> 00:23:20,161
(speaks in foreign language)
474
00:23:20,161 --> 00:23:22,350
The experiment clearly shows
475
00:23:22,350 --> 00:23:26,400
that the crater floor has risen as an entire platform
476
00:23:26,400 --> 00:23:29,828
and that the area surrounding the crater has sunk.
477
00:23:29,828 --> 00:23:31,590
(speaks in foreign language)
478
00:23:31,590 --> 00:23:35,250
This explains how the cenotes were formed.
479
00:23:35,250 --> 00:23:37,440
Because rock along the crater's rim
480
00:23:37,440 --> 00:23:41,070
moves in opposite directions after the impact,
481
00:23:41,070 --> 00:23:44,070
cracks form in the much younger rock.
482
00:23:44,070 --> 00:23:47,700
This ultimately creates cenotes.
483
00:23:47,700 --> 00:23:49,170
Everything fits
484
00:23:49,170 --> 00:23:51,750
and the crime scene of the killer asteroid
485
00:23:51,750 --> 00:23:53,790
seems to have been found.
486
00:23:53,790 --> 00:23:56,460
But for definitive proof, the scientists
487
00:23:56,460 --> 00:23:58,650
must obtain samples of the rock
488
00:23:58,650 --> 00:24:01,113
from inside the submerged crater.
489
00:24:02,129 --> 00:24:03,309
(waves crashing)
490
00:24:03,309 --> 00:24:04,650
(dramatic music)
491
00:24:04,650 --> 00:24:09,600
In 2016, professor Sean Gulick from the University of Texas
492
00:24:09,600 --> 00:24:12,900
led an international group of scientists on a mission
493
00:24:12,900 --> 00:24:15,987
to drill into the Chicxulub crater.
494
00:24:15,987 --> 00:24:17,280
(dramatic music)
495
00:24:17,280 --> 00:24:19,200
Right now, beneath the the drilling rig
496
00:24:19,200 --> 00:24:21,660
and beneath where we're sitting on this transport vessel
497
00:24:21,660 --> 00:24:23,910
is the peak ring of Chicxulub.
498
00:24:23,910 --> 00:24:28,323
It's buried by 66 million years of limestones.
499
00:24:29,190 --> 00:24:31,740
We've picked this site because it's the place
500
00:24:31,740 --> 00:24:34,814
where the peak ring is closest to the modern sea floor.
501
00:24:34,814 --> 00:24:37,737
(dramatic music)
502
00:24:37,737 --> 00:24:39,237
Woo hoo, here we go.
503
00:24:39,237 --> 00:24:41,396
(dramatic music)
504
00:24:41,396 --> 00:24:42,229
All right.
505
00:24:43,740 --> 00:24:47,250
It has taken years to prepare for the drilling,
506
00:24:47,250 --> 00:24:49,410
but the scientists may finally prove
507
00:24:49,410 --> 00:24:51,608
the crater's significance.
508
00:24:51,608 --> 00:24:53,130
(dramatic music)
509
00:24:53,130 --> 00:24:56,100
It was an opportunity to sort of put to bed
510
00:24:56,100 --> 00:24:57,990
all the questions about,
511
00:24:57,990 --> 00:25:01,500
is it for sure that, that impact crater
512
00:25:01,500 --> 00:25:05,550
is the one that is observed as the global boundary layer?
513
00:25:05,550 --> 00:25:08,430
Is it for sure that that is the impact
514
00:25:08,430 --> 00:25:10,590
that actually caused the mass extinction,
515
00:25:10,590 --> 00:25:12,359
66 million years ago?
516
00:25:12,359 --> 00:25:14,280
(dramatic music)
517
00:25:14,280 --> 00:25:17,730
The water is very shallow at the drilling spot,
518
00:25:17,730 --> 00:25:20,790
so the team must use unconventional equipment
519
00:25:20,790 --> 00:25:23,623
to sample the ancient sediments.
520
00:25:23,623 --> 00:25:25,350
(dramatic music)
521
00:25:25,350 --> 00:25:28,020
We used a land mining rig actually
522
00:25:28,020 --> 00:25:30,600
and hung it off the bow of the vessel
523
00:25:30,600 --> 00:25:34,440
and drilled for two months into the crater.
524
00:25:34,440 --> 00:25:36,270
And then we continued drilling, literally,
525
00:25:36,270 --> 00:25:40,881
until we ran outta money at 1,335 meters down.
526
00:25:40,881 --> 00:25:42,120
(dramatic music)
527
00:25:42,120 --> 00:25:44,460
And so when we were finally on the drilling platform
528
00:25:44,460 --> 00:25:46,047
drilling into the impact crater
529
00:25:46,047 --> 00:25:50,463
and the first cores came up, it was just a heady experience.
530
00:25:52,080 --> 00:25:54,390
Look at the color of the matrix,
531
00:25:54,390 --> 00:25:57,870
it goes from green to red.
Red.
532
00:25:57,870 --> 00:25:58,703
That looks like melt.
533
00:25:58,703 --> 00:25:59,850
That does look like melt, doesn't it?
534
00:25:59,850 --> 00:26:00,720
That looks like a giant
535
00:26:00,720 --> 00:26:02,130
cast of melt.
Yeah.
536
00:26:02,130 --> 00:26:05,160
We are now fully into impact rocks directly.
537
00:26:05,160 --> 00:26:08,280
It's really easy to see because it's granite.
538
00:26:08,280 --> 00:26:13,280
And so you can see these spotted leopard looking big chunks.
539
00:26:13,410 --> 00:26:18,210
We reached rocks that were clearly not normally laid down
540
00:26:18,210 --> 00:26:20,940
as you see in the ocean sediments, but something else.
541
00:26:20,940 --> 00:26:23,940
And we realized of course, that, that was the impact.
542
00:26:23,940 --> 00:26:25,080
The evidence suggests
543
00:26:25,080 --> 00:26:28,890
that a six mile wide asteroid impacted Earth at this site
544
00:26:28,890 --> 00:26:31,024
completely altering the rock.
545
00:26:31,024 --> 00:26:32,010
(dramatic music)
546
00:26:32,010 --> 00:26:34,200
One of the amazing things was just the, if you will,
547
00:26:34,200 --> 00:26:36,090
the resolution of the record.
548
00:26:36,090 --> 00:26:38,580
'Cause normally, you know, at most a centimeter
549
00:26:38,580 --> 00:26:41,476
might be a thousand years in an ocean core,
550
00:26:41,476 --> 00:26:43,320
in a scientific drill core.
551
00:26:43,320 --> 00:26:46,350
And in this case, we actually had 130 meters,
552
00:26:46,350 --> 00:26:49,170
that because it had a tsunami layer on the top
553
00:26:49,170 --> 00:26:51,270
and had impact melt on the bottom,
554
00:26:51,270 --> 00:26:54,390
we could say was effectively all deposited
555
00:26:54,390 --> 00:26:56,250
within the first day of the Cenozoic.
556
00:26:56,250 --> 00:26:58,170
So you can normally think about drilling
557
00:26:58,170 --> 00:27:00,930
into the ocean sediments that you might get,
558
00:27:00,930 --> 00:27:04,170
you know, a sense about a time.
559
00:27:04,170 --> 00:27:06,570
And because we have 130 meters,
560
00:27:06,570 --> 00:27:10,500
it's like we have an entire novel about a single day
561
00:27:10,500 --> 00:27:12,930
preserved in the rock record.
562
00:27:12,930 --> 00:27:15,030
All of the Chicxulub drill cores
563
00:27:15,030 --> 00:27:18,510
are safely stored in the expeditions repository
564
00:27:18,510 --> 00:27:20,792
at College Station, Texas.
565
00:27:20,792 --> 00:27:22,260
(dramatic music)
566
00:27:22,260 --> 00:27:25,920
This is where Sean Gulick examines them hoping to prove
567
00:27:25,920 --> 00:27:30,243
that Chicxulub was in fact ground zero of the impact.
568
00:27:31,440 --> 00:27:33,900
So it turns out that the peak ring itself
569
00:27:33,900 --> 00:27:36,180
was made of granites, but these granites
570
00:27:36,180 --> 00:27:38,520
are fundamentally altered by having been
571
00:27:38,520 --> 00:27:39,840
in an impact crater.
572
00:27:39,840 --> 00:27:41,940
It is much more porous than it should be.
573
00:27:41,940 --> 00:27:43,260
It's actually weaker.
574
00:27:43,260 --> 00:27:46,230
In fact, you could crush it with your hands.
575
00:27:46,230 --> 00:27:48,060
And in fact, that's proof positive
576
00:27:48,060 --> 00:27:50,100
that this is in an impact crater
577
00:27:50,100 --> 00:27:52,800
that you see these planet affirmation features
578
00:27:52,800 --> 00:27:55,980
and all of these other observations of shock
579
00:27:55,980 --> 00:27:58,593
also say it has to be in an impact crater.
580
00:27:59,820 --> 00:28:01,920
The analysis shows that Chicxulub
581
00:28:01,920 --> 00:28:04,533
is definitely an impact crater.
582
00:28:05,430 --> 00:28:08,700
But can the scientist conclude that this impact
583
00:28:08,700 --> 00:28:11,223
led to the demise of the dinosaurs?
584
00:28:12,390 --> 00:28:15,330
What is viewed as the global boundary layer, right,
585
00:28:15,330 --> 00:28:16,590
what is viewed as the evidence
586
00:28:16,590 --> 00:28:18,971
everywhere outside of the crater,
587
00:28:18,971 --> 00:28:21,060
that there was an impact
588
00:28:21,060 --> 00:28:23,970
is the presence of of iridium, right.
589
00:28:23,970 --> 00:28:26,160
And so one of the interesting questions here is,
590
00:28:26,160 --> 00:28:28,440
do we find it in the crater itself?
591
00:28:28,440 --> 00:28:30,930
Can we directly tie the impact crater
592
00:28:30,930 --> 00:28:32,640
back to this global layer?
593
00:28:32,640 --> 00:28:35,430
And so to check that, we sent samples
594
00:28:35,430 --> 00:28:38,340
to four different laboratories around the world.
595
00:28:38,340 --> 00:28:41,970
And what we discovered is all the laboratories agreed
596
00:28:41,970 --> 00:28:43,620
that right at that location,
597
00:28:43,620 --> 00:28:45,750
right in that singular spot in the core
598
00:28:45,750 --> 00:28:48,210
is where the iridium is found.
599
00:28:48,210 --> 00:28:50,310
All of the evidence suggests
600
00:28:50,310 --> 00:28:53,700
that Chicxulub is ground zero.
601
00:28:53,700 --> 00:28:57,600
By finding the iridium layer in the crater
602
00:28:57,600 --> 00:29:00,150
directly on top of all of the deposits
603
00:29:00,150 --> 00:29:02,880
generated by the impact in the first day,
604
00:29:02,880 --> 00:29:05,973
to weeks, to months, to a few years,
605
00:29:05,973 --> 00:29:09,420
we were able to conclusively say that, you know,
606
00:29:09,420 --> 00:29:13,203
Chicxulub absolutely is the location of the impact.
607
00:29:14,310 --> 00:29:17,280
The drill cores provide indisputable proof
608
00:29:17,280 --> 00:29:19,650
that the Chicxulub crater was formed
609
00:29:19,650 --> 00:29:22,053
by a six mile wide asteroid.
610
00:29:23,487 --> 00:29:27,720
And the impact occurred at the exact time the dinosaurs
611
00:29:27,720 --> 00:29:31,623
and many other life forms vanished from our planet.
612
00:29:32,670 --> 00:29:35,850
To understand if this single event was strong enough
613
00:29:35,850 --> 00:29:37,950
to cause the mass extinction,
614
00:29:37,950 --> 00:29:39,600
the scientists must calculate
615
00:29:39,600 --> 00:29:43,293
the effects an impactor of size would have on the earth.
616
00:29:45,930 --> 00:29:47,223
Freiburg, Germany.
617
00:29:48,210 --> 00:29:50,490
At the Fraunhofer Ernst-Mach-Institut,
618
00:29:50,490 --> 00:29:53,130
Frank Schafer and Professor Thomas Kenkmann
619
00:29:53,130 --> 00:29:57,210
want to see what happens when a six mile diameter asteroid
620
00:29:57,210 --> 00:30:01,050
crashes into a planet at several thousand miles per hour.
621
00:30:01,050 --> 00:30:03,210
For this experiment, they engage
622
00:30:03,210 --> 00:30:06,809
one of the fastest guns ever created.
623
00:30:06,809 --> 00:30:08,730
(speaks in foreign language)
624
00:30:08,730 --> 00:30:10,950
So this is our projectile,
625
00:30:10,950 --> 00:30:13,260
the down-scaled asteroid.
626
00:30:13,260 --> 00:30:16,320
The aim is to achieve as much speed as possible
627
00:30:16,320 --> 00:30:19,290
to simulate the impact on the Chicxulub crater
628
00:30:19,290 --> 00:30:20,326
in the laboratory.
629
00:30:20,326 --> 00:30:23,250
(speaks in foreign language)
630
00:30:23,250 --> 00:30:25,410
The two stage, light gas gun
631
00:30:25,410 --> 00:30:28,920
uses a combination of highly pressurized gases
632
00:30:28,920 --> 00:30:30,540
and rapid expansion
633
00:30:30,540 --> 00:30:34,530
that will accelerate projectiles at super high speeds.
634
00:30:34,530 --> 00:30:37,320
The first stage initiates the acceleration,
635
00:30:37,320 --> 00:30:40,200
while the second stage provides additional propulsion
636
00:30:40,200 --> 00:30:42,673
for even greater velocity.
637
00:30:42,673 --> 00:30:44,040
(speaks in foreign language)
638
00:30:44,040 --> 00:30:45,990
Unlike natural craters,
639
00:30:45,990 --> 00:30:49,140
here we are witnessing the process as it happens.
640
00:30:49,140 --> 00:30:51,570
Chicxulub is a gigantic crater,
641
00:30:51,570 --> 00:30:53,580
but we only see the end result
642
00:30:53,580 --> 00:30:56,460
of a very, very complex process.
643
00:30:56,460 --> 00:31:00,240
Here we can experience all stages of the formation.
644
00:31:00,240 --> 00:31:02,070
The high speed cameras allow us
645
00:31:02,070 --> 00:31:05,493
to follow what is happening at microsecond intervals.
646
00:31:05,493 --> 00:31:07,500
(speaks in foreign language)
647
00:31:07,500 --> 00:31:08,700
The gas gun cannon
648
00:31:08,700 --> 00:31:13,650
can launch projectiles at more than 17,000 miles per hour.
649
00:31:13,650 --> 00:31:16,413
So the team must take extra precautions.
650
00:31:17,502 --> 00:31:20,411
(machine beeping)
651
00:31:20,411 --> 00:31:21,244
(speaks in foreign language)
652
00:31:21,244 --> 00:31:24,401
Three, two, one, fire.
653
00:31:24,401 --> 00:31:27,068
(cannon firing)
654
00:31:33,850 --> 00:31:34,683
(speaks in foreign language)
655
00:31:34,683 --> 00:31:37,410
Nominal trigger points, all right.
656
00:31:37,410 --> 00:31:39,480
I think that was a successful shot.
657
00:31:39,480 --> 00:31:41,423
Yeah, let's take a look at it.
658
00:31:43,050 --> 00:31:44,700
In addition to analyzing
659
00:31:44,700 --> 00:31:46,410
the high speed footage,
660
00:31:46,410 --> 00:31:49,893
the team wants to investigate the crater that was created.
661
00:31:51,023 --> 00:31:52,260
(speaks in foreign language)
662
00:31:52,260 --> 00:31:54,510
The crater is quite deep,
663
00:31:54,510 --> 00:31:57,450
flat at the bottom and full of dust.
664
00:31:57,450 --> 00:31:59,300
There's a lot of dust in the chamber.
665
00:32:00,660 --> 00:32:04,470
You can see steep edges in the limestone and in the center.
666
00:32:04,470 --> 00:32:06,608
This seems to be the deep rock.
667
00:32:06,608 --> 00:32:08,284
(dramatic music)
668
00:32:08,284 --> 00:32:10,110
(speaks in foreign language)
669
00:32:10,110 --> 00:32:11,490
What really surprises me
670
00:32:11,490 --> 00:32:14,490
is the amount of dust and small splinters
671
00:32:14,490 --> 00:32:15,870
that have been produced.
672
00:32:15,870 --> 00:32:18,600
It's very finely fragmented material.
673
00:32:18,600 --> 00:32:20,550
You can see it, you can feel it,
674
00:32:20,550 --> 00:32:22,230
you can hold it in your hand.
675
00:32:22,230 --> 00:32:23,910
It's fine dust.
676
00:32:23,910 --> 00:32:27,180
And this dust was also ejected by Chicxulub.
677
00:32:27,180 --> 00:32:29,818
But this topic is still subject of debate.
678
00:32:29,818 --> 00:32:33,510
(speaks in foreign language)
679
00:32:33,510 --> 00:32:37,079
The impact didn't just make a crater.
680
00:32:37,079 --> 00:32:40,050
(dramatic music)
681
00:32:40,050 --> 00:32:43,590
The incredible force changed the molecular structure
682
00:32:43,590 --> 00:32:45,448
of the once solid rock.
683
00:32:45,448 --> 00:32:47,319
(dramatic music)
684
00:32:47,319 --> 00:32:48,270
(speaks in foreign language)
685
00:32:48,270 --> 00:32:51,330
What we see here is the mineral quartz.
686
00:32:51,330 --> 00:32:53,760
There are strange straight lines.
687
00:32:53,760 --> 00:32:56,640
These lines are exactly what we were looking for.
688
00:32:56,640 --> 00:32:59,130
They are shock indicators that show us
689
00:32:59,130 --> 00:33:01,773
that a shockwave has traveled through the rock.
690
00:33:02,640 --> 00:33:04,740
That's what the experiment shows us.
691
00:33:04,740 --> 00:33:07,743
It's just like the subsurface of the Chicxulub crater.
692
00:33:09,930 --> 00:33:11,940
Professor Kai Wunnermann
693
00:33:11,940 --> 00:33:16,203
must now apply data from the experiment to the proper scale.
694
00:33:17,220 --> 00:33:20,910
He plans to calculate the effects from the asteroid impact,
695
00:33:20,910 --> 00:33:22,733
66 million years ago.
696
00:33:22,733 --> 00:33:24,394
(keyboard keys clacking)
697
00:33:24,394 --> 00:33:25,740
(speaks in foreign language)
698
00:33:25,740 --> 00:33:27,750
Now we can actually simulate
699
00:33:27,750 --> 00:33:30,210
the right dimensions and quantities
700
00:33:30,210 --> 00:33:31,863
such as the right gravity,
701
00:33:33,270 --> 00:33:34,770
and that should tell us something
702
00:33:34,770 --> 00:33:37,608
about how much energy was released.
703
00:33:37,608 --> 00:33:40,170
(speaks in foreign language)
704
00:33:40,170 --> 00:33:42,120
The colossal asteroid was on
705
00:33:42,120 --> 00:33:44,853
an inescapable collision course with earth,
706
00:33:46,620 --> 00:33:49,530
traveling at an astronomical speed.
707
00:33:49,530 --> 00:33:52,080
When the behemoth pierced the atmosphere,
708
00:33:52,080 --> 00:33:53,943
it ignited in the sky.
709
00:33:54,960 --> 00:33:59,960
It hurdled towards earth at nearly 45,000 miles per hour.
710
00:34:00,210 --> 00:34:03,690
Its path of compressed air caused a shockwave
711
00:34:03,690 --> 00:34:06,540
to reverberate across the planet's surface
712
00:34:06,540 --> 00:34:08,133
with a cosmic boom.
713
00:34:09,000 --> 00:34:10,890
Blazing a trail of fire,
714
00:34:10,890 --> 00:34:14,131
the asteroid plummeted towards the ground.
715
00:34:14,131 --> 00:34:14,964
(asteroid crashing)
716
00:34:14,964 --> 00:34:17,070
Then it crashed into the shallow ocean
717
00:34:17,070 --> 00:34:18,870
with apocalyptic force,
718
00:34:18,870 --> 00:34:22,920
the impact released 4.5 billion times the energy
719
00:34:22,920 --> 00:34:25,296
of the Hiroshima atomic bomb.
720
00:34:25,296 --> 00:34:27,540
(speaks in foreign language)
721
00:34:27,540 --> 00:34:30,750
This energy that is released melts the rock,
722
00:34:30,750 --> 00:34:32,373
and it doesn't just melt it,
723
00:34:33,300 --> 00:34:35,100
it actually reaches temperatures
724
00:34:35,100 --> 00:34:39,270
in the region of 36,000 degrees Fahrenheit,
725
00:34:39,270 --> 00:34:42,532
that leads to the rock being vaporized.
726
00:34:42,532 --> 00:34:45,210
(asteroid crashing)
727
00:34:45,210 --> 00:34:48,303
The energy it released was devastating.
728
00:34:49,320 --> 00:34:52,110
After a flash illuminates the sky,
729
00:34:52,110 --> 00:34:56,193
an eerie bright white sphere grows over the impact site.
730
00:34:57,270 --> 00:35:00,420
Bedrock melts into a scalding plasma
731
00:35:00,420 --> 00:35:04,620
that releases a shockwave even greater than the first.
732
00:35:04,620 --> 00:35:07,470
Even deep rocks are so heavily fractured,
733
00:35:07,470 --> 00:35:09,430
they fly like water.
734
00:35:09,430 --> 00:35:10,440
(speaks in foreign language)
735
00:35:10,440 --> 00:35:12,720
It's actually very similar to what you see
736
00:35:12,720 --> 00:35:14,490
when you throw a stone into water,
737
00:35:14,490 --> 00:35:16,020
which also creates a crater.
738
00:35:16,020 --> 00:35:18,900
It usually doesn't last very long, we hardly see it.
739
00:35:18,900 --> 00:35:20,280
But it also collapses
740
00:35:20,280 --> 00:35:22,410
and then it splashes up in the middle
741
00:35:22,410 --> 00:35:25,140
and it forms what we call a central mountain.
742
00:35:25,140 --> 00:35:28,302
So it resembles the splashing up in the middle.
743
00:35:28,302 --> 00:35:29,610
(dramatic music)
744
00:35:29,610 --> 00:35:32,550
The surrounding ocean water is displaced
745
00:35:32,550 --> 00:35:36,003
or instantly evaporates when the asteroid strikes.
746
00:35:37,560 --> 00:35:40,650
Molten crust forms a temporary mountain
747
00:35:40,650 --> 00:35:43,023
taller than any on earth today.
748
00:35:44,880 --> 00:35:49,457
This tower of fiery liquid plasma collapses quickly.
749
00:35:49,457 --> 00:35:51,601
(dramatic music)
750
00:35:51,601 --> 00:35:53,640
(speaks in foreign language)
751
00:35:53,640 --> 00:35:55,050
And at the same time,
752
00:35:55,050 --> 00:35:57,330
the water that was previously displaced
753
00:35:57,330 --> 00:35:59,700
flows back into the crater.
754
00:35:59,700 --> 00:36:02,250
And through the collapse of this temporary mountain,
755
00:36:02,250 --> 00:36:04,710
in interaction with the returning water
756
00:36:04,710 --> 00:36:07,770
waves are generated that are nearly a mile high
757
00:36:07,770 --> 00:36:11,700
and then spread out comparable to tsunami waves.
758
00:36:11,700 --> 00:36:14,940
And this of course, all also devastates coastlines
759
00:36:14,940 --> 00:36:17,938
thousands of miles away from the impact center.
760
00:36:17,938 --> 00:36:20,520
(speaks in foreign language)
761
00:36:20,520 --> 00:36:23,250
The impact destroys everything living
762
00:36:23,250 --> 00:36:25,590
in the immediate vicinity.
763
00:36:25,590 --> 00:36:29,523
First it is burned, then blasted by the shockwave.
764
00:36:31,470 --> 00:36:34,980
Anything left drowns in a miles high tsunami.
765
00:36:34,980 --> 00:36:38,730
But such an apocalyptic wave should have left evidence
766
00:36:38,730 --> 00:36:40,599
in the rock record.
767
00:36:40,599 --> 00:36:43,432
(dramatic music)
768
00:36:44,670 --> 00:36:47,580
800 miles from the impact crater,
769
00:36:47,580 --> 00:36:52,580
Sean Gulick searches for clues in the Brazos River in Texas.
770
00:36:53,133 --> 00:36:56,250
(dramatic music)
771
00:36:56,250 --> 00:36:57,960
This is one of the locations
772
00:36:57,960 --> 00:37:01,740
where the exact time of the impact comes to the surface.
773
00:37:01,740 --> 00:37:03,870
So right where the end of the Cretaceous
774
00:37:03,870 --> 00:37:06,090
and the start of the Paleogene is preserved,
775
00:37:06,090 --> 00:37:07,710
it's preserved in the Brazos River
776
00:37:07,710 --> 00:37:09,840
and it's preserved within little waterfalls
777
00:37:09,840 --> 00:37:11,640
within the creeks nearby.
778
00:37:11,640 --> 00:37:14,820
So it's a great place to search for evidence of the impact.
779
00:37:14,820 --> 00:37:17,160
Gulick wants to build a complete picture
780
00:37:17,160 --> 00:37:19,170
of one of the most terrifying days
781
00:37:19,170 --> 00:37:21,600
in the history of our planet.
782
00:37:21,600 --> 00:37:24,440
Three quarters of life on earth died out
783
00:37:24,440 --> 00:37:26,820
in the same geologic moment.
784
00:37:26,820 --> 00:37:31,290
It's an incredible exposure of the K-Pg boundary.
785
00:37:31,290 --> 00:37:33,450
Basically the shaley stuff at the bottom
786
00:37:33,450 --> 00:37:34,830
predates the impact.
787
00:37:34,830 --> 00:37:37,320
This is the time of the dinosaurs
788
00:37:37,320 --> 00:37:39,420
and the large marine reptiles.
789
00:37:39,420 --> 00:37:41,250
And then this is the boundary.
790
00:37:41,250 --> 00:37:43,860
And the contact is actually, you know,
791
00:37:43,860 --> 00:37:47,460
it's kind of erosional, it's got a lot of energy in it
792
00:37:47,460 --> 00:37:50,280
that carves into what was there before.
793
00:37:50,280 --> 00:37:53,820
And then a series of events are basically recorded
794
00:37:53,820 --> 00:37:56,910
in this, more than a meter of material,
795
00:37:56,910 --> 00:37:58,890
that is the K-Pg boundary.
796
00:37:58,890 --> 00:38:02,310
You see it here, right, these are these cross stratified,
797
00:38:02,310 --> 00:38:04,410
these dipping layers that are present
798
00:38:04,410 --> 00:38:06,090
right here within the rocks
799
00:38:06,090 --> 00:38:08,520
and this high energy looking material above it,
800
00:38:08,520 --> 00:38:10,590
of the finer particles.
801
00:38:10,590 --> 00:38:14,370
All of this probably represents the arrival of the tsunami
802
00:38:14,370 --> 00:38:16,620
here in central Texas,
803
00:38:16,620 --> 00:38:18,840
The tsunami is global
804
00:38:18,840 --> 00:38:22,320
with an estimated force 30,000 times greater
805
00:38:22,320 --> 00:38:24,603
than any in recorded history.
806
00:38:25,890 --> 00:38:30,180
Each piece of evidence gives the scientists a clear snapshot
807
00:38:30,180 --> 00:38:34,020
of how the disaster unfolded at the end of the Cretaceous.
808
00:38:34,020 --> 00:38:36,630
If you were living 66 million years ago,
809
00:38:36,630 --> 00:38:39,180
the effects of the impact would depend
810
00:38:39,180 --> 00:38:42,600
where you were compared to ground zero
811
00:38:42,600 --> 00:38:43,920
in the Yucatan Peninsula.
812
00:38:43,920 --> 00:38:47,370
So we're at about 1300 kilometers away from the site.
813
00:38:47,370 --> 00:38:50,460
Anything within probably 1500 kilometers
814
00:38:50,460 --> 00:38:54,480
would've experienced the direct heat from the impact itself.
815
00:38:54,480 --> 00:38:57,990
In other words, the the impact explosion was so large,
816
00:38:57,990 --> 00:38:59,910
you could see it over the horizon.
817
00:38:59,910 --> 00:39:00,900
You would've been killed
818
00:39:00,900 --> 00:39:03,360
at the speed of light by just the thermal radiation
819
00:39:03,360 --> 00:39:04,980
coming out from the impact.
820
00:39:04,980 --> 00:39:06,870
If you were a little bit further away,
821
00:39:06,870 --> 00:39:08,820
you would've felt the hurricane force winds,
822
00:39:08,820 --> 00:39:11,010
you'd have felt the earthquakes.
823
00:39:11,010 --> 00:39:12,450
The extent of the impact
824
00:39:12,450 --> 00:39:15,060
is impossible to imagine.
825
00:39:15,060 --> 00:39:19,530
Thousands of miles away on both Pacific and Atlantic shores,
826
00:39:19,530 --> 00:39:21,810
enormous tsunamis, wreak havoc,
827
00:39:21,810 --> 00:39:24,303
inundating everything in their paths.
828
00:39:25,740 --> 00:39:27,600
The presence of of a tsunami layer,
829
00:39:27,600 --> 00:39:30,450
especially one as thick as this, you know,
830
00:39:30,450 --> 00:39:32,130
1300 kilometers away from the crater,
831
00:39:32,130 --> 00:39:34,920
is just testament to the incredible energy.
832
00:39:34,920 --> 00:39:37,710
In fact, the energy released by the impact
833
00:39:37,710 --> 00:39:39,990
is billions of times the energy
834
00:39:39,990 --> 00:39:42,510
of a World War II era nuclear bomb.
835
00:39:42,510 --> 00:39:44,850
But despite the epic scale of the event,
836
00:39:44,850 --> 00:39:47,010
Gulick needs more evidence to support
837
00:39:47,010 --> 00:39:50,340
that the impact had global consequences for life.
838
00:39:50,340 --> 00:39:53,700
The thermal radiation, the tsunamis and the hurricanes
839
00:39:53,700 --> 00:39:55,230
were not sufficient to cause
840
00:39:55,230 --> 00:40:00,230
the extinction of 75% of species 66 million years ago.
841
00:40:00,990 --> 00:40:03,510
He must search for additional clues
842
00:40:03,510 --> 00:40:07,860
to uncover what happened to dinosaurs worldwide.
843
00:40:07,860 --> 00:40:11,070
By carefully analyzing the prehistory recorded
844
00:40:11,070 --> 00:40:12,900
in the K-Pg rocks,
845
00:40:12,900 --> 00:40:15,930
he finds a clue that might explain their demise.
846
00:40:15,930 --> 00:40:17,790
Yeah, you can see the spherules,
847
00:40:17,790 --> 00:40:20,700
yeah, that there's little glassy looks,
848
00:40:20,700 --> 00:40:23,070
but you can still see little hints
849
00:40:23,070 --> 00:40:24,300
of the layers of spherules
850
00:40:24,300 --> 00:40:26,200
that are all present inside this rock.
851
00:40:27,570 --> 00:40:30,330
Spherules look like little glass balls.
852
00:40:30,330 --> 00:40:33,180
The largest you might ever find would be maybe a centimeter,
853
00:40:33,180 --> 00:40:34,680
but most of the time they're millimeters
854
00:40:34,680 --> 00:40:36,600
or even sub millimeters in scale.
855
00:40:36,600 --> 00:40:39,240
So they're either referred to as melt
856
00:40:39,240 --> 00:40:42,900
that ejected out of the crater and cooled into a sphere
857
00:40:42,900 --> 00:40:45,060
and traveled and then rained down.
858
00:40:45,060 --> 00:40:48,330
Or they're actually vapor in the plume
859
00:40:48,330 --> 00:40:50,820
that condensed into a glass,
860
00:40:50,820 --> 00:40:52,803
you know, sphere that then rained down.
861
00:40:54,660 --> 00:40:57,090
These innocuous glass balls are key
862
00:40:57,090 --> 00:41:00,714
to the events set in motion after the impact.
863
00:41:00,714 --> 00:41:02,550
The spherules are found
864
00:41:02,550 --> 00:41:05,790
on the K-Pg boundary around the world
865
00:41:05,790 --> 00:41:08,250
and clearly coincide with the impact
866
00:41:08,250 --> 00:41:12,420
at the end of the Cretaceous 66 million years ago.
867
00:41:12,420 --> 00:41:15,933
They are a solid connection to that moment in time.
868
00:41:18,243 --> 00:41:20,400
(asteroid crashing)
869
00:41:20,400 --> 00:41:23,400
When the asteroid slams into the bedrock,
870
00:41:23,400 --> 00:41:27,420
molten and vaporized rock is thrown into the sky,
871
00:41:27,420 --> 00:41:29,734
some even reaches space.
872
00:41:29,734 --> 00:41:30,900
(dramatic music)
873
00:41:30,900 --> 00:41:33,360
Small droplets of rock in the plume,
874
00:41:33,360 --> 00:41:35,490
condense and solidify,
875
00:41:35,490 --> 00:41:39,266
falling back to earth as tiny glass beads.
876
00:41:39,266 --> 00:41:42,300
(dramatic music)
877
00:41:42,300 --> 00:41:45,570
So in any location around the world
878
00:41:45,570 --> 00:41:48,540
that has a well-preserved boundary layer,
879
00:41:48,540 --> 00:41:51,210
you see material that arrived as ejecta
880
00:41:51,210 --> 00:41:54,300
and you see material that was basically a dust
881
00:41:54,300 --> 00:41:55,740
that rained out later.
882
00:41:55,740 --> 00:41:59,010
The ejecta was moving at at high velocities.
883
00:41:59,010 --> 00:42:01,710
And so that is the spherules that we see here
884
00:42:01,710 --> 00:42:04,410
is a big wedge shaped deposit here
885
00:42:04,410 --> 00:42:06,210
underneath the tsunami layer.
886
00:42:06,210 --> 00:42:07,950
And they're little glass balls that,
887
00:42:07,950 --> 00:42:09,535
you know, rained out of the sky.
888
00:42:09,535 --> 00:42:12,453
They traveled here at kilometers per second, speed.
889
00:42:13,290 --> 00:42:15,420
Could the ejecta have contributed
890
00:42:15,420 --> 00:42:17,763
to the extinction of the dinosaurs.
891
00:42:18,628 --> 00:42:20,580
(dramatic music)
892
00:42:20,580 --> 00:42:23,860
Back in Hell Creek, Peter Larson is analyzing
893
00:42:23,860 --> 00:42:28,053
how the Chicxulub effects unfolded across the planet.
894
00:42:31,890 --> 00:42:34,410
So here we have a piece of the boundary clay
895
00:42:34,410 --> 00:42:36,213
and the coal that's just above it.
896
00:42:37,650 --> 00:42:42,300
So if we kind of scrape away the boundary clay a little bit,
897
00:42:42,300 --> 00:42:45,480
and I'm not sure that that's soot,
898
00:42:45,480 --> 00:42:48,600
but sometimes we can find a layer of soot
899
00:42:48,600 --> 00:42:51,360
that's actually right above the very top
900
00:42:51,360 --> 00:42:52,710
of the boundary clay here.
901
00:42:52,710 --> 00:42:55,173
So that is indicative of forest fires.
902
00:42:56,220 --> 00:42:58,380
Remnants of ancient burned forests
903
00:42:58,380 --> 00:43:01,440
are expected at an impact site.
904
00:43:01,440 --> 00:43:04,020
But Larson is in South Dakota,
905
00:43:04,020 --> 00:43:07,310
2000 miles from where the meteorite struck.
906
00:43:07,310 --> 00:43:09,750
(dramatic music)
907
00:43:09,750 --> 00:43:12,090
All of this molten material was flung up
908
00:43:12,090 --> 00:43:14,550
out of the atmosphere and rained down,
909
00:43:14,550 --> 00:43:16,140
that as they came through the atmosphere,
910
00:43:16,140 --> 00:43:18,450
they heated the atmosphere up to the point
911
00:43:18,450 --> 00:43:21,450
where basically all the forests and all the plants
912
00:43:21,450 --> 00:43:24,180
had to burn, the atmosphere was so hot,
913
00:43:24,180 --> 00:43:27,540
as some have estimated is more than 2000 degrees
914
00:43:27,540 --> 00:43:29,699
at the surface of the earth, in some places.
915
00:43:29,699 --> 00:43:30,532
(dramatic music)
916
00:43:30,532 --> 00:43:31,365
(fire raging)
917
00:43:31,365 --> 00:43:33,213
Earth is on fire,
918
00:43:34,170 --> 00:43:36,750
wildfires are reaching globally
919
00:43:36,750 --> 00:43:41,364
with trees and life within the forest turning to ash.
920
00:43:41,364 --> 00:43:42,990
(fire raging)
921
00:43:42,990 --> 00:43:47,583
Earth is scorched in the aftermath and many creatures die.
922
00:43:48,690 --> 00:43:51,360
But was this the definitive mechanism
923
00:43:51,360 --> 00:43:53,538
that led to the mass extinction?
924
00:43:53,538 --> 00:43:57,337
(dinosaur growling)
925
00:43:57,337 --> 00:43:59,910
(dramatic music)
926
00:43:59,910 --> 00:44:02,880
Sean Gulick returns to the lab to reexamine
927
00:44:02,880 --> 00:44:05,790
the Chicxulub crater drill cores.
928
00:44:05,790 --> 00:44:09,333
They might hold a hidden piece that will solve the puzzle.
929
00:44:10,260 --> 00:44:13,953
Sean discovers a strange anomaly he missed before.
930
00:44:15,060 --> 00:44:18,000
It isn't because of what he finds,
931
00:44:18,000 --> 00:44:21,600
but about what he doesn't see.
932
00:44:21,600 --> 00:44:25,200
There is a glaring absence of sulfur bearing minerals
933
00:44:25,200 --> 00:44:26,877
and they should be here.
934
00:44:26,877 --> 00:44:28,290
(dramatic music)
935
00:44:28,290 --> 00:44:32,430
And one of the key clues to understanding,
936
00:44:32,430 --> 00:44:35,550
you know, what ultimately caused the extinction event
937
00:44:35,550 --> 00:44:40,380
turned out to be that even though we knew the original rocks
938
00:44:40,380 --> 00:44:45,240
of the Yucatan Peninsula were 30 to 50% sulfur rich rocks,
939
00:44:45,240 --> 00:44:48,930
we don't find any evidence of the anhydrite or the gypsum
940
00:44:48,930 --> 00:44:50,490
left in the crater.
941
00:44:50,490 --> 00:44:53,903
And so the conclusion that comes from that
942
00:44:53,903 --> 00:44:57,660
is that preferentially, all of these sulfur risk rocks
943
00:44:57,660 --> 00:44:59,373
got put up into the atmosphere.
944
00:45:00,270 --> 00:45:03,840
66 million years ago, life was doomed
945
00:45:03,840 --> 00:45:06,870
when the Chicxulub asteroid impacted a spot
946
00:45:06,870 --> 00:45:09,486
that caused marine rocks to vaporize.
947
00:45:09,486 --> 00:45:10,590
(dramatic music)
948
00:45:10,590 --> 00:45:15,077
Copious amounts of sulfur were released into the sky.
949
00:45:15,077 --> 00:45:16,530
(asteroid crashing)
950
00:45:16,530 --> 00:45:19,230
We would've had an incredible amount of sulfur.
951
00:45:19,230 --> 00:45:23,760
In fact, the estimates are something like 335 gigatons
952
00:45:23,760 --> 00:45:26,673
of sulfur would've been put into the atmosphere.
953
00:45:27,930 --> 00:45:29,250
A chemical reaction
954
00:45:29,250 --> 00:45:33,030
between sulfur from the vaporized rocks and water
955
00:45:33,030 --> 00:45:37,050
expels more than 300 gigatons of sulfur aerosols
956
00:45:37,050 --> 00:45:38,343
into the atmosphere.
957
00:45:39,360 --> 00:45:42,900
The aerosols scatter incoming solar radiation,
958
00:45:42,900 --> 00:45:45,180
which reduces the sun's ability
959
00:45:45,180 --> 00:45:47,910
to warm the surface of the earth.
960
00:45:47,910 --> 00:45:51,330
This leads to rapid planetary cooling.
961
00:45:51,330 --> 00:45:54,360
Even if you use just a hundred gigatons of sulfur
962
00:45:54,360 --> 00:45:56,010
and you run a climate model,
963
00:45:56,010 --> 00:46:00,870
you can drop the global temperatures by 25 degrees Celsius,
964
00:46:00,870 --> 00:46:02,580
just with, you know, a third
965
00:46:02,580 --> 00:46:04,813
of what we think we put into the atmosphere.
966
00:46:04,813 --> 00:46:06,390
(asteroid crashing)
967
00:46:06,390 --> 00:46:08,670
Plunging temperatures on the planet
968
00:46:08,670 --> 00:46:12,063
are just one terrible effect produced by the sulfur.
969
00:46:13,470 --> 00:46:16,762
The ensuing darkness is even deadlier.
970
00:46:16,762 --> 00:46:19,260
(dramatic music)
971
00:46:19,260 --> 00:46:21,360
There's the dust and the sulfur in the atmospheres
972
00:46:21,360 --> 00:46:24,540
that cause darkness or maybe twilight for years.
973
00:46:24,540 --> 00:46:26,970
That meant that all of the things
974
00:46:26,970 --> 00:46:29,070
that eat the sun for their energy,
975
00:46:29,070 --> 00:46:33,420
so phytoplankton in the oceans and plants on land,
976
00:46:33,420 --> 00:46:35,850
that these would've started dying out
977
00:46:35,850 --> 00:46:39,270
and therefore, those that ate the phytoplankton
978
00:46:39,270 --> 00:46:41,670
or ate the plants on land started dying out,
979
00:46:41,670 --> 00:46:44,397
and then the carnivores that ate them started dying out,
980
00:46:44,397 --> 00:46:48,306
and it caused this collapse all the way up the food chain.
981
00:46:48,306 --> 00:46:49,440
(dramatic music)
982
00:46:49,440 --> 00:46:53,220
The impact winter lasts many years.
983
00:46:53,220 --> 00:46:56,883
It freezes and starves most life on our planet.
984
00:46:57,720 --> 00:47:00,570
Darkness in the wake of the Chicxulub impact,
985
00:47:00,570 --> 00:47:05,400
66 million years ago, spells death for plants.
986
00:47:05,400 --> 00:47:08,640
Consequently, most herbivores die,
987
00:47:08,640 --> 00:47:11,493
which leads to the death of carnivores too.
988
00:47:12,660 --> 00:47:14,490
As the food chain collapses,
989
00:47:14,490 --> 00:47:19,260
75% of all life forms on earth become extinct.
990
00:47:19,260 --> 00:47:22,440
Sulfur turns out to be the real killer.
991
00:47:22,440 --> 00:47:25,470
Perhaps the dinosaurs would've survived
992
00:47:25,470 --> 00:47:29,100
if the asteroid hadn't crashed into sulfur rich rocks.
993
00:47:29,100 --> 00:47:31,680
If it had actually hit 30 seconds earlier
994
00:47:31,680 --> 00:47:32,880
and hit the Atlantic ocean
995
00:47:32,880 --> 00:47:35,850
or 30 seconds later and hit the Pacific Ocean,
996
00:47:35,850 --> 00:47:39,600
instead of sulfur rich rocks and limestone dust,
997
00:47:39,600 --> 00:47:41,430
we'd have just had water vapor
998
00:47:41,430 --> 00:47:43,950
and probably not a massive extinction event
999
00:47:43,950 --> 00:47:46,197
like happened 66 million years ago.
1000
00:47:46,197 --> 00:47:48,570
(dramatic music)
1001
00:47:48,570 --> 00:47:51,060
But how could any living thing
1002
00:47:51,060 --> 00:47:53,583
have survived this catastrophe?
1003
00:47:56,100 --> 00:47:58,620
The Chicxulub impact triggered the last
1004
00:47:58,620 --> 00:48:02,220
of the five mass extinctions in earth's history.
1005
00:48:02,220 --> 00:48:04,110
But if there's one lesson we can learn
1006
00:48:04,110 --> 00:48:06,210
from the previous cataclysms,
1007
00:48:06,210 --> 00:48:09,063
it's that life always finds a way.
1008
00:48:10,170 --> 00:48:12,900
It takes around 20 years for the atmosphere
1009
00:48:12,900 --> 00:48:16,113
to be cleared of dust and sulfate aerosols.
1010
00:48:17,700 --> 00:48:20,733
Once again, the sun pierces through a clean sky.
1011
00:48:21,810 --> 00:48:23,283
Plants reappear.
1012
00:48:24,450 --> 00:48:26,026
But what about the animals?
1013
00:48:26,026 --> 00:48:27,300
(dramatic music)
1014
00:48:27,300 --> 00:48:29,490
Paleontologist Philipe Havlik
1015
00:48:29,490 --> 00:48:32,550
joins Pete Larson at Hell Creek.
1016
00:48:32,550 --> 00:48:34,620
(dramatic music)
1017
00:48:34,620 --> 00:48:37,080
They're hunting for clues that might reveal
1018
00:48:37,080 --> 00:48:40,023
how life reemerged after the impact.
1019
00:48:41,400 --> 00:48:43,950
Near the edge of the K-Pg boundary,
1020
00:48:43,950 --> 00:48:46,173
they spot a familiar fossil.
1021
00:48:48,450 --> 00:48:49,440
Holy crap.
1022
00:48:49,440 --> 00:48:51,690
This is not a rock.
That is not a rock,
1023
00:48:51,690 --> 00:48:52,714
that's a dinosaur boat.
1024
00:48:52,714 --> 00:48:54,120
Oh wow.
1025
00:48:54,120 --> 00:48:56,190
Oh, and look at how close we are.
1026
00:48:56,190 --> 00:48:57,690
Oh man.
1027
00:48:57,690 --> 00:48:58,860
Oh, that's so cool.
1028
00:48:58,860 --> 00:49:02,520
It's a tail vertebra from a duck-billed dinosaur.
1029
00:49:02,520 --> 00:49:06,270
It's like, holy crap, right here, right here,
1030
00:49:06,270 --> 00:49:08,220
half a meter below the boundary.
1031
00:49:08,220 --> 00:49:10,810
But it's actually washed down, so it maybe was
1032
00:49:11,670 --> 00:49:13,290
really, really close to the boundary.
1033
00:49:13,290 --> 00:49:18,270
So this dinosaur might have seen that asteroid
1034
00:49:18,270 --> 00:49:19,350
crash into the earth.
1035
00:49:19,350 --> 00:49:21,960
I mean, it's possible, it's close enough
1036
00:49:21,960 --> 00:49:23,730
that it could have washed down that much.
1037
00:49:23,730 --> 00:49:24,563
Oh yeah.
1038
00:49:24,563 --> 00:49:25,440
For sure.
1039
00:49:25,440 --> 00:49:27,780
Certainly one of the last dinosaurs to live,
1040
00:49:27,780 --> 00:49:29,283
no question about that.
1041
00:49:30,420 --> 00:49:31,833
You poor unlucky thing.
1042
00:49:33,420 --> 00:49:35,460
Soon they find signs
1043
00:49:35,460 --> 00:49:38,278
of what they are really searching for.
1044
00:49:38,278 --> 00:49:39,510
(dramatic music)
1045
00:49:39,510 --> 00:49:40,494
No.
1046
00:49:40,494 --> 00:49:41,406
Is it?
1047
00:49:41,406 --> 00:49:42,470
I think it's a little,
1048
00:49:42,470 --> 00:49:44,380
I think it's a little multituberculate tooth.
1049
00:49:44,380 --> 00:49:46,136
Come on, come on.
1050
00:49:46,136 --> 00:49:46,969
I think so.
1051
00:49:46,969 --> 00:49:48,213
It can't be.
1052
00:49:48,213 --> 00:49:49,680
Is that cool?
1053
00:49:49,680 --> 00:49:50,550
(both laughing)
1054
00:49:50,550 --> 00:49:52,117
Hey, I can see the rootlets.
Holy moly.
1055
00:49:52,117 --> 00:49:54,090
It is.
Ah, ah.
1056
00:49:54,090 --> 00:49:56,430
So this is a multituberculate tooth.
1057
00:49:56,430 --> 00:49:58,500
Multituberculates lived in Hell Creek,
1058
00:49:58,500 --> 00:49:59,760
they lived in the Cretaceous
1059
00:49:59,760 --> 00:50:02,700
and they made it all the way through into the paleo scene.
1060
00:50:02,700 --> 00:50:04,650
They're a very small mammal.
1061
00:50:04,650 --> 00:50:07,080
With over 200 distinct species,
1062
00:50:07,080 --> 00:50:09,810
these rodent like mammals range in size
1063
00:50:09,810 --> 00:50:14,340
from tiny mice like creatures to the bulk of modern beavers.
1064
00:50:14,340 --> 00:50:16,860
They leave diverse lifestyles,
1065
00:50:16,860 --> 00:50:18,840
some tunnel underground,
1066
00:50:18,840 --> 00:50:22,050
while others navigate canopies like squirrels
1067
00:50:22,050 --> 00:50:23,973
or hop across the landscape.
1068
00:50:24,900 --> 00:50:27,240
These little guys were able to survive
1069
00:50:27,240 --> 00:50:29,880
simply because they were so tiny and so small.
1070
00:50:29,880 --> 00:50:32,280
They could hide in little cracks and crevices
1071
00:50:32,280 --> 00:50:35,280
into a burrow where a dinosaur couldn't go.
1072
00:50:35,280 --> 00:50:37,500
They also didn't need all the food to eat.
1073
00:50:37,500 --> 00:50:42,150
So if this animal could survive on dried out,
1074
00:50:42,150 --> 00:50:44,940
and maybe even partially burnt plants,
1075
00:50:44,940 --> 00:50:46,680
or if it was a carnivore,
1076
00:50:46,680 --> 00:50:49,440
it could exist in the carcass of a dinosaur,
1077
00:50:49,440 --> 00:50:51,420
there's lots of food there, you know, lots of jerky
1078
00:50:51,420 --> 00:50:54,360
that this animal could exist on for a long, long time.
1079
00:50:54,360 --> 00:50:57,390
And so it was able to survive that nuclear winter
1080
00:50:57,390 --> 00:51:00,090
that was the result of that asteroid
1081
00:51:00,090 --> 00:51:01,290
crashing into the earth.
1082
00:51:02,340 --> 00:51:05,370
As the impact winter finally fades away.
1083
00:51:05,370 --> 00:51:09,810
Small mammals like these find ways to thrive in a world
1084
00:51:09,810 --> 00:51:12,780
that had been leveled by catastrophe.
1085
00:51:12,780 --> 00:51:15,870
They are the true survivors.
1086
00:51:15,870 --> 00:51:19,920
They owe their success to one special characteristic,
1087
00:51:19,920 --> 00:51:20,943
being small.
1088
00:51:21,900 --> 00:51:23,370
The larger the animal,
1089
00:51:23,370 --> 00:51:26,520
the more energy it requires to survive.
1090
00:51:26,520 --> 00:51:30,270
When food is scarce, size is a liability
1091
00:51:30,270 --> 00:51:32,793
and only the smallest persevere.
1092
00:51:33,870 --> 00:51:36,330
When all these dinosaurs died,
1093
00:51:36,330 --> 00:51:38,250
not only were there some survivors,
1094
00:51:38,250 --> 00:51:41,190
but it left open ecological niches,
1095
00:51:41,190 --> 00:51:43,380
which were kinda like job opportunities.
1096
00:51:43,380 --> 00:51:46,830
And so little guys like this, little tiny, tiny mammals
1097
00:51:46,830 --> 00:51:48,330
grew into things like,
1098
00:51:48,330 --> 00:51:52,140
eventually into things like elephants.
1099
00:51:52,140 --> 00:51:55,890
Today, mammals are extremely diverse.
1100
00:51:55,890 --> 00:51:58,920
From the tiny to the colossal,
1101
00:51:58,920 --> 00:52:03,030
mammals span a remarkable range of sizes.
1102
00:52:03,030 --> 00:52:06,240
They inhabit wildly different ecosystems
1103
00:52:06,240 --> 00:52:10,350
from icy arctic tundras to lush rainforests
1104
00:52:10,350 --> 00:52:12,570
and arid deserts.
1105
00:52:12,570 --> 00:52:17,373
They enjoy the air, the water and the land.
1106
00:52:18,300 --> 00:52:21,120
Surprisingly, dinosaurs didn't become
1107
00:52:21,120 --> 00:52:23,730
completely extinct either.
1108
00:52:23,730 --> 00:52:27,570
Some of the small avian like dinosaurs survived
1109
00:52:27,570 --> 00:52:30,390
and evolved into birds.
1110
00:52:30,390 --> 00:52:34,950
Their ancestors thrive today with a vast array of colors,
1111
00:52:34,950 --> 00:52:37,830
shapes and behaviors.
1112
00:52:37,830 --> 00:52:39,810
The dramatic chain of events
1113
00:52:39,810 --> 00:52:42,600
that began with a Chicxulub asteroid impact,
1114
00:52:42,600 --> 00:52:47,600
66 million years ago, drastically altered life on earth.
1115
00:52:49,110 --> 00:52:53,490
All non avian dinosaurs, including the iconic T-Rex,
1116
00:52:53,490 --> 00:52:57,870
could not survive the long-term effects of the impact.
1117
00:52:57,870 --> 00:53:02,070
Their demise would pave the way to the rise of mammals
1118
00:53:02,070 --> 00:53:05,937
and ultimately to the evolution of humankind.
1119
00:53:06,889 --> 00:53:09,722
(dramatic music)