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(theatrical music)
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Earth is born out of chaos and catastrophe.
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(planets explode)
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Despite such hostile conditions,
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life emerges on our planet.
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But it must withstand deadly disasters again and again.
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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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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,
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life as we know it would not exist
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on our "Fateful Planet".
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(theatrical music)
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66 million years ago when an asteroid impacted Earth,
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75% of all species became extinct,
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including all the non-avian dinosaurs.
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The tenacious life that re-emerged in the Cenozoic
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would ultimately lead to humankind today.
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But violent Earth forces and extreme climate changes
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continue to threaten our path forward.
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So scientists must investigate the past
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to prevent our extinction in the future.
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And while we have survived thus far,
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more dire calamities loom on the horizon
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that may again threaten all life as we know it,
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including us.
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(wind blowing)
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Morocco.
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Just two hours west of Marrakesh,
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archeologists have uncovered the oldest remains
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of homo sapiens, modern humans.
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Professor Abdeljalil Bouzouggar from the National Institute
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of Archeological Sciences and Heritage in Morocco
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hopes that the ancient bones will reveal new information
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about the development of humankind.
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The extinction of the non-avian dinosaurs
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66 million years ago paved the way
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to the development of other mammals.
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This leads to the development of hominids,
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including homo sapiens.
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Humankind has had a long evolutionary journey.
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Fossil records combined with DNA studies
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reveal the last common ancestor
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of both humans and chimpanzees
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live between five and 6 million years ago.
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After that, the species diverged.
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The hominids developed an upright posture.
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This was a critical point in human evolution
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because it freed our hands to handle objects.
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An upright posture is shared by all hominid species
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that would appear throughout Earth's history.
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Today, only one remains: homo sapiens.
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To learn more about our early ancestors,
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Abdeljalil meets with Professor Abdelouahed Ben-Ncer
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at the excavation site of Jebel Irhoud.
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The professor discovered remnants
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of an ancient human shelter
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that also yields groundbreaking information
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about human evolution.
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This is an exact replica of a skull
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found here by Ben-Ncer.
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It has rewritten the beginning of our human history.
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It's exciting, I'm holding out
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the oldest example of the homo sapiens in the world,
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because the date is around 315,000 years ago.
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We thought that homo sapiens existed in Africa
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around 200,000 years ago.
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With this new discovery in Jebel Irhoud,
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the scientists pushed back the age
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of more than 100,000 years ago.
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(light music)
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Ben-Ncer also found sophisticated tools
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and weapons from the Middle Paleolithic
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between 250,000 and 25,000 years ago.
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They represent a significant step in human evolution,
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proof of the growing intelligence
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that sets us apart from all other animals on Earth.
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In this place, there are a lot of fireplaces,
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and fire were used for many reasons.
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One of them was to cook the meat.
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That means that we will increase the protein in this food,
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which was really very necessary and helpful for the body,
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but especially for the brain,
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which was really something,
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a huge step in the human evolution
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in this part of the world.
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A larger, more organized brain
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was key to the next stages of our evolution.
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A day's drive from Jebel Irhoud,
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Professor Bouzouggar has found more evidence
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of increasingly refined evolution
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in our early ancestors.
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(cinematic music)
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Grotte Des Pigeons is a cave that was discovered
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by scientists over a century ago.
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This is a treasured trove.
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It's helping us to better understand homo sapiens,
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not only from a biological perspective,
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but also from a social and cultural perspective.
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Hi Miriam.
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How are you?
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I'm good, thank you.
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Professor Bouzouggar works
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with PhD student Miriam Benagati
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to record any archeological finds in the cave.
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Looks like there's something unusual here.
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(light music)
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Can you see?
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Yeah.
It's perforated.
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That's a shell bead.
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The most interesting and fascinating things we found
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are shell beads.
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These snails, they are marines
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and they came from the coast.
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So those people around 82,000 years ago,
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they went to the sea to collect these species,
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which means that it is really a long distance walking
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in order to collect such snails.
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The closest coastal spot today
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is about 30 miles from the Grotte Des Pigeons.
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Bouzouggar is certain this is where our ancestors
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must have collected the shells.
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Here in the beach,
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you would have seen thousands of shells,
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but our ancestors collected only tiny shells.
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'Cause they are only three centimeters,
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so they can't be brought to the cave
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to be consumed by these people.
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You have to get thousands of these tiny shells
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to even get half a kilo of the shells.
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So it can't have been
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a food source.
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So the question is,
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why did our ancestors
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bring them to the cave?
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When the scientists examined the shell beads,
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they realized stone or bone tools
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had been used to perforate them.
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This is the first time when homo sapiens
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will use something which is not a tool,
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but something which probably was decorating their bodies
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or probably their clothes.
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This crafting of shell beads
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mark significant progress in our evolution.
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To make such things like shell beads,
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you need to be able to talk,
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to explain to other members of the group
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that in one or two days walking from the cave,
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there is a coast where these shells are available.
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Our ancestors didn't just travel to the coast.
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They would migrate out of Africa
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in search of new food sources,
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and their journey would take them to the site
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of a deadly catastrophe.
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It was an event that had potential to cause
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the demise of humankind.
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A world away from Morocco,
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Antarctica holds surprising clues
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about a calamity our ancestors had to face.
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Ice can store vital details about our planet's history
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over millions of years.
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In the 1990s, scientists discovered something astonishing
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in ice cores dating back to 74,000 years ago,
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extremely high levels of sulfur.
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The presence of sulfur was the first indication
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that something catastrophic might have happened
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and the magnitude of the deposits revealed
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that it was possibly cataclysmic.
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An event of this magnitude
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had the potential to wipe out our early ancestors,
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and perhaps all life on Earth.
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Scientists scoured the planet for the possible origin
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of such a massive eruption.
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Their search finally drew them
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to one of the few features on Earth
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capable of producing such an event:
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the Pacific Ring of Fire.
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It's a vast chain of volcanoes that stretches
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more than 25,000 miles
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from the southern tip of South America
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along the west coast of North America,
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across the Bering Strait and down into Japan
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and New Zealand.
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The Ring of Fire boasts 75%
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of all active volcanoes on Earth.
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They form a horseshoe-like shape
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around the edge of the Pacific Ocean
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due to the movement of tectonic plates.
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This is a geologically active region,
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where the Pacific Plate slides beneath
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the surrounding continental plates
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in a process called subduction.
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(tense music)
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When the heavy Pacific Plate sinks below
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the lighter continental plates,
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pressure turns the dense mantle
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of the Pacific Plate into magma
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and pushes it towards Earth's surface.
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Over millions of years,
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this has created the chain of volcanoes.
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Sumatra.
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Indonesia is a country within the Ring of Fire.
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It has some of the highest rates
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of volcanic activity on the planet.
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So, geologist Dr. Martin Danisik has come here
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to search for clues about what may have happened
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74,000 years ago.
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His investigation begins at Mount Sinabung,
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where a deposit near the active volcano
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has caught his attention.
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(rock cracks)
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I'm using a hand lens to actually check
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what kind of composition we have in this particular rock.
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I can see it's very pores.
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I can see different minerals here.
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This rock is called ignimbrite.
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Ignimbrite is a volcanic rock
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that forms during explosive eruptions.
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The large size of this deposit
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indicates it was produced by a massive event.
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But although further analysis reveals
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that the eruption occurred 74,000 years ago,
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the geologist is doubtful it can be tied
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to the sulfur-heavy cores found in Antarctica.
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Danisik believes this volcano is not the culprit.
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Sinabung Volcano is simply too small.
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It's not capable to produce this size of pyroclastic flow.
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And what that means is that
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there must be a gigantic volcano
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that produced these rocks.
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(tense music)
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Danisik's search for possible sources
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of the eruption leads him to one
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of Sumatra's biggest landmarks.
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This is Lake Toba.
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It's enormous.
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It goes a hundred kilometers this way.
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It's about 30 kilometers wide.
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Lake Toba is so vast
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it contains an island the size of Singapore at its center.
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The island itself is also peculiar,
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with sheer cliffs rising unusually high
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above Lake Toba surface.
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(light music)
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This is Samosir Island.
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It's highest point is over 1600 meters.
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Now, we are at 900 meters.
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This can give you an idea of how high
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the island rises above this lake.
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Dr. Danisik is able to access
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the island's sub-surface at a local quarry.
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And an outcrop reveals a surprising layer of sediment.
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It's actually sediments that form in lake.
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Now, we are probably 400 meters
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above the current lake level.
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So the lake can be seen over here,
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but these sediments formed below water,
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if that makes sense.
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(tense music)
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The scientist sees
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only one explanation for this.
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The answer is that Samosir Island
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is a huge block that used to be below water,
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and then it was pushed up, was uplifted
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by a leftover magma in a magma chamber.
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Essentially we're standing in the middle of a giant volcano.
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(tense music)
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The extinct volcano is so large
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it's difficult to even recognize it from the ground,
275
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and Lake Toba is the caldera.
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And approximately 74,000 years ago,
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this volcano produced a gigantic eruption.
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We call it super eruption.
279
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(tense music)
280
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Toba exploded in a cataclysmic eruption
281
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that released gas, ash, and magma
282
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on an unprecedented scale.
283
00:14:25,380 --> 00:14:28,890
The super volcano shot more than a thousand cubic miles
284
00:14:28,890 --> 00:14:30,873
of volcanic matter into the sky.
285
00:14:32,160 --> 00:14:33,960
The billowing clouds heated
286
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to over 1,000 degrees Fahrenheit,
287
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spelled death for any vegetation in their path.
288
00:14:42,210 --> 00:14:43,440
When the plume collapsed,
289
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it sent more than 8 trillion tons of volcanic material
290
00:14:46,830 --> 00:14:51,488
hurdling towards the ground at over 250 miles an hour.
291
00:14:51,488 --> 00:14:52,561
(intense music)
292
00:14:52,561 --> 00:14:53,394
(thunder claps)
293
00:14:53,394 --> 00:14:58,351
A lethal pyroclastic flow devastated everything in its path.
294
00:14:58,351 --> 00:15:01,080
(pyroclastic flow swooshes)
295
00:15:01,080 --> 00:15:05,760
Probably everything within a radius of 100 kilometers
296
00:15:05,760 --> 00:15:08,283
was obliterated by pyroclastic flows.
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Volcanic debris spread across
298
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the Indian Ocean and into Asia,
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covering several million square miles
300
00:15:16,740 --> 00:15:18,183
of the planet's surface.
301
00:15:19,080 --> 00:15:23,670
But, long-term consequences of the mega eruption
302
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would be even deadlier than the immediate aftermath.
303
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Sulfur dioxide emitted from the volcano
304
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formed a veil around the globe,
305
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blocking out sunlight.
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00:15:35,400 --> 00:15:38,070
Some scientists believe Earth's temperature
307
00:15:38,070 --> 00:15:40,780
dropped by up to 16 degrees Fahrenheit
308
00:15:42,930 --> 00:15:46,080
On a global scale, it's been proposed
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that this super eruption could have caused
310
00:15:49,920 --> 00:15:52,290
a bottleneck in human population.
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00:15:52,290 --> 00:15:54,870
Meaning, that the number of individuals
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00:15:54,870 --> 00:15:56,820
living on this planet would reduce
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to 3,000 to 10,000 individuals.
314
00:16:00,450 --> 00:16:03,450
If true, humankind came close to extinction
315
00:16:03,450 --> 00:16:05,790
74,000 years ago,
316
00:16:05,790 --> 00:16:08,550
and the theory assumes Africa and Asia
317
00:16:08,550 --> 00:16:11,154
sheltered the few survivors.
318
00:16:11,154 --> 00:16:12,780
(light music)
319
00:16:12,780 --> 00:16:16,140
Back in Morocco, Professor Bouzouggar has been investigating
320
00:16:16,140 --> 00:16:19,713
how our ancestors reacted to the super eruption.
321
00:16:21,090 --> 00:16:24,393
He isn't convinced of the bottleneck theory.
322
00:16:26,430 --> 00:16:30,270
We didn't only found 82,000 years old shell beads,
323
00:16:30,270 --> 00:16:33,750
but we found others which are much younger,
324
00:16:33,750 --> 00:16:38,750
like this one which is dated to around 70,000 years ago.
325
00:16:38,880 --> 00:16:40,680
This means that the Toba eruption
326
00:16:40,680 --> 00:16:43,830
didn't act as a bottleneck for homo sapiens.
327
00:16:43,830 --> 00:16:45,990
'Cause here what we can see is an evolution
328
00:16:45,990 --> 00:16:48,750
of homo sapiens without disruption.
329
00:16:48,750 --> 00:16:50,130
While the Toba eruption
330
00:16:50,130 --> 00:16:53,370
may not have endangered humankind survival,
331
00:16:53,370 --> 00:16:57,240
Earth still pose challenges for homo sapiens.
332
00:16:57,240 --> 00:16:59,340
Evidence of an environmental shift
333
00:16:59,340 --> 00:17:01,680
can be found within the cave.
334
00:17:01,680 --> 00:17:05,580
Our ancestors apparently needed to keep warm.
335
00:17:05,580 --> 00:17:08,850
This edge was probably used in order to cut,
336
00:17:08,850 --> 00:17:12,450
you know, branches of the trees.
337
00:17:12,450 --> 00:17:14,970
And this is something very new.
338
00:17:14,970 --> 00:17:17,700
This is a new technology in this context.
339
00:17:17,700 --> 00:17:21,873
And this shift could be related to a climate change.
340
00:17:22,860 --> 00:17:25,440
To understand how the environment changed,
341
00:17:25,440 --> 00:17:27,660
Professor Bouzouggar and his student
342
00:17:27,660 --> 00:17:30,120
search for hidden clues.
343
00:17:30,120 --> 00:17:33,120
The researchers want to understand how eruptions
344
00:17:33,120 --> 00:17:35,010
can affect the environment,
345
00:17:35,010 --> 00:17:36,990
because during the millennia that followed
346
00:17:36,990 --> 00:17:38,850
the Toba super eruption,
347
00:17:38,850 --> 00:17:42,153
Earth posed new challenges for homo sapiens.
348
00:17:44,970 --> 00:17:47,580
When analyzing these charcoals,
349
00:17:47,580 --> 00:17:51,600
we understand that in this part of the world, in Africa,
350
00:17:51,600 --> 00:17:53,613
the climate was dry.
351
00:17:54,690 --> 00:17:59,463
And if we compare it with Europe during the Ice Age,
352
00:18:00,900 --> 00:18:02,763
it's slightly different.
353
00:18:03,840 --> 00:18:05,790
The climate had changed
354
00:18:05,790 --> 00:18:08,913
due to the shifting of Earth's position to the sun.
355
00:18:11,370 --> 00:18:13,850
In the North, glaciers grew.
356
00:18:13,850 --> 00:18:17,490
50,000 years after the Toba eruption,
357
00:18:17,490 --> 00:18:18,993
they reached their maximum.
358
00:18:20,550 --> 00:18:23,280
Our early ancestors forged their way
359
00:18:23,280 --> 00:18:26,073
through the frozen wilderness of an Ice Age.
360
00:18:27,330 --> 00:18:31,110
Sharing the challenges with colossal creatures,
361
00:18:31,110 --> 00:18:34,473
somehow humans adapted and thrived.
362
00:18:35,310 --> 00:18:38,883
This Ice Age boasted a surprising array of megafauna.
363
00:18:40,980 --> 00:18:43,680
Majestic mammoths roamed the plains
364
00:18:43,680 --> 00:18:46,683
and saber-toothed cats proud for prey.
365
00:18:49,110 --> 00:18:52,773
Humans co-existed with these magnificent animals.
366
00:18:53,610 --> 00:18:57,300
Pleistocene cave art reveals the art ancestors had
367
00:18:57,300 --> 00:18:58,710
for these creatures
368
00:18:58,710 --> 00:19:02,553
as they immortalized their encounters on the stone walls.
369
00:19:05,580 --> 00:19:08,040
As the Ice Age drew to a close,
370
00:19:08,040 --> 00:19:10,830
the changing climate altered habitats
371
00:19:10,830 --> 00:19:13,530
and transformed landscapes.
372
00:19:13,530 --> 00:19:17,520
Soon, the balance between humans and animals
373
00:19:17,520 --> 00:19:19,323
also began to shift.
374
00:19:20,550 --> 00:19:22,680
During the Ice Age,
375
00:19:22,680 --> 00:19:26,740
homo sapiens was hunting megafauna for meat
376
00:19:27,660 --> 00:19:31,953
and to use their hides for shelters or for warms.
377
00:19:33,270 --> 00:19:37,920
And scientists now know that homo sapiens
378
00:19:37,920 --> 00:19:41,430
was sufficiently reproducing,
379
00:19:41,430 --> 00:19:46,380
and by having the size of the population growing,
380
00:19:46,380 --> 00:19:50,163
they were in need of more resources, food resources.
381
00:19:52,440 --> 00:19:55,260
The human population was growing,
382
00:19:55,260 --> 00:19:57,210
resources were dwindling,
383
00:19:57,210 --> 00:19:59,940
and competition for them with us
384
00:19:59,940 --> 00:20:03,513
may have caused the numbers of megafauna to decrease.
385
00:20:04,530 --> 00:20:06,963
The huge animals began to disappear.
386
00:20:08,730 --> 00:20:12,270
People hunted the once abundant Ice Age herds,
387
00:20:12,270 --> 00:20:16,023
and the animals weren't able to reproduce quickly enough.
388
00:20:18,510 --> 00:20:20,760
Homo sapiens group survived
389
00:20:20,760 --> 00:20:24,030
because they have a long history,
390
00:20:24,030 --> 00:20:29,030
and they were adopting also some kind of hunting strategies
391
00:20:30,960 --> 00:20:33,513
which helped them to survived.
392
00:20:35,820 --> 00:20:38,670
The megafauna numbers rapidly declined
393
00:20:38,670 --> 00:20:41,790
over about 2,000 years.
394
00:20:41,790 --> 00:20:44,580
Most of the majestic creatures vanished,
395
00:20:44,580 --> 00:20:47,883
never to roam the landscape again.
396
00:20:50,160 --> 00:20:53,223
Around 10,000 years ago, ice melted,
397
00:20:54,330 --> 00:20:56,700
which means that homo sapiens grew.
398
00:20:56,700 --> 00:21:00,750
They need a new to adapt a new behavior,
399
00:21:00,750 --> 00:21:04,260
and this behavior will lead
400
00:21:04,260 --> 00:21:06,750
to what we now know about storing
401
00:21:06,750 --> 00:21:11,004
and also about domesticating plants and other animals.
402
00:21:11,004 --> 00:21:12,990
(light music)
403
00:21:12,990 --> 00:21:16,110
Crop cultivation and the keeping of livestock
404
00:21:16,110 --> 00:21:18,780
provided our ancestors with a stable
405
00:21:18,780 --> 00:21:20,613
and reliable food supply.
406
00:21:21,570 --> 00:21:25,980
This radical shift from a nomadic, hunter-gatherer lifestyle
407
00:21:25,980 --> 00:21:30,630
to an agrarian one would define the Neolithic Revolution.
408
00:21:30,630 --> 00:21:33,780
And when you have this kind of activity,
409
00:21:33,780 --> 00:21:35,463
you need private property.
410
00:21:36,570 --> 00:21:39,663
When you got this, you need to build cities.
411
00:21:41,370 --> 00:21:44,613
And then you need to defend these cities.
412
00:21:46,380 --> 00:21:50,463
Settlements grew into towns and then cities.
413
00:21:51,300 --> 00:21:55,350
Trade became vital as civilizations were created.
414
00:21:55,350 --> 00:21:58,380
This was the beginning of the modern world,
415
00:21:58,380 --> 00:22:00,451
and it happened quickly.
416
00:22:00,451 --> 00:22:01,440
(light music)
417
00:22:01,440 --> 00:22:03,420
We have reshaped our planet
418
00:22:03,420 --> 00:22:05,730
and even traveled beyond it.
419
00:22:05,730 --> 00:22:08,790
But regardless of humankind's ingenuity,
420
00:22:08,790 --> 00:22:13,665
Earth's primal forces remain beyond our control.
421
00:22:13,665 --> 00:22:16,165
(light music)
422
00:22:19,427 --> 00:22:21,123
Hebgen Lake, Montana.
423
00:22:22,290 --> 00:22:27,290
We are a success as a species and we continue to progress.
424
00:22:27,360 --> 00:22:30,750
But on our planet and in the cosmos,
425
00:22:30,750 --> 00:22:34,770
unexpected threats to our survival still loom.
426
00:22:34,770 --> 00:22:37,890
These bare trees are silent witnesses
427
00:22:37,890 --> 00:22:40,560
to a catastrophe that unfolded here
428
00:22:40,560 --> 00:22:42,873
during the summer of 1959.
429
00:22:44,040 --> 00:22:48,240
Seismologist Dr. Jamie Farrell is investigating an event
430
00:22:48,240 --> 00:22:51,813
that was triggered by the ceaseless reshaping of Earth.
431
00:22:52,890 --> 00:22:54,633
On the night of August 17th,
432
00:22:55,470 --> 00:22:58,860
there was an earthquake, magnitude 7.3,
433
00:22:58,860 --> 00:23:00,600
that shook the entire region.
434
00:23:00,600 --> 00:23:03,690
Unfortunately, there were some people in the Madison Canyon,
435
00:23:03,690 --> 00:23:05,910
downstream from Hebgen Lake at a campground,
436
00:23:05,910 --> 00:23:08,580
and just above them, the mountain gave way
437
00:23:08,580 --> 00:23:09,900
due to the shaking.
438
00:23:09,900 --> 00:23:12,570
And there was a huge landslide, rock slide that came down
439
00:23:12,570 --> 00:23:13,916
on the campground.
440
00:23:13,916 --> 00:23:16,916
(suspenseful music)
441
00:23:18,330 --> 00:23:20,240
One of America's worst series of earthquakes
442
00:23:20,240 --> 00:23:22,770
in this century felt throughout the Northwest
443
00:23:22,770 --> 00:23:25,860
centers its forests on Southwestern Montana.
444
00:23:25,860 --> 00:23:29,730
In Madison River Canyon, 50 million tons of earth and rock,
445
00:23:29,730 --> 00:23:31,980
the top of an 8,000-foot mountain
446
00:23:31,980 --> 00:23:33,930
thundered across a forest campground
447
00:23:33,930 --> 00:23:36,060
in one of the biggest landslides.
448
00:23:36,060 --> 00:23:39,150
So many people were buried underneath that landslide
449
00:23:39,150 --> 00:23:40,918
that are still there today.
450
00:23:40,918 --> 00:23:42,510
(morose music)
451
00:23:42,510 --> 00:23:45,630
The event is tragic proof of the immense amount
452
00:23:45,630 --> 00:23:48,573
of seismic activity that occurs in this region.
453
00:23:50,340 --> 00:23:54,090
Around 2,000 earthquakes occur here every year.
454
00:23:54,090 --> 00:23:56,760
Many are never even felt.
455
00:23:56,760 --> 00:23:57,960
So right here where we're standing now,
456
00:23:57,960 --> 00:24:00,191
we're now at the actual fault scarp here
457
00:24:00,191 --> 00:24:02,070
from the Hebgen Lake earthquake in 1959.
458
00:24:02,070 --> 00:24:03,090
And what you see here is
459
00:24:03,090 --> 00:24:05,730
you see this big break in the earth here,
460
00:24:05,730 --> 00:24:07,800
and prior to the earthquake,
461
00:24:07,800 --> 00:24:10,260
these two levels would've been on the same level.
462
00:24:10,260 --> 00:24:13,080
And instantaneously, as soon as the earthquake happened,
463
00:24:13,080 --> 00:24:15,990
this side here mostly just dropped down along the fault.
464
00:24:15,990 --> 00:24:18,259
So, six meters of offset,
465
00:24:18,259 --> 00:24:19,680
(fingers snaps)
like that.
466
00:24:19,680 --> 00:24:21,450
But something must have triggered
467
00:24:21,450 --> 00:24:23,910
this fatal landslide.
468
00:24:23,910 --> 00:24:26,550
Jamie's research leads him to a huge
469
00:24:26,550 --> 00:24:29,283
and famous potential threat nearby.
470
00:24:30,570 --> 00:24:35,223
Yellowstone, the first national park in the world.
471
00:24:36,240 --> 00:24:40,140
Continuous hydrothermal activity beneath the park surface
472
00:24:40,140 --> 00:24:42,810
creates a natural spectacle,
473
00:24:42,810 --> 00:24:46,740
but it also hides a potentially lethal catastrophe
474
00:24:46,740 --> 00:24:49,770
much larger than the Toba eruption.
475
00:24:49,770 --> 00:24:51,900
So here we're looking at Grand Prismatic Spring.
476
00:24:51,900 --> 00:24:54,170
This is one of the iconic hot springs
477
00:24:54,170 --> 00:24:55,260
in Yellowstone National Park.
478
00:24:55,260 --> 00:24:58,260
It's one of the largest hot springs in the world,
479
00:24:58,260 --> 00:24:59,940
and this is one of many
480
00:24:59,940 --> 00:25:01,860
of the thermal features here we have in Yellowstone.
481
00:25:01,860 --> 00:25:05,313
We have over 10,000 thermal features here in the park.
482
00:25:06,600 --> 00:25:08,190
The incredible attractions
483
00:25:08,190 --> 00:25:11,580
draw millions of visitors every year.
484
00:25:11,580 --> 00:25:13,680
But while they're stunning,
485
00:25:13,680 --> 00:25:15,870
the hydrothermal vents and pools
486
00:25:15,870 --> 00:25:17,703
can quickly become dangerous.
487
00:25:20,040 --> 00:25:24,393
Geologic activity in Yellowstone must be closely monitored.
488
00:25:25,230 --> 00:25:28,470
One of Jamie's roles is to probe the source
489
00:25:28,470 --> 00:25:31,203
of the hydrothermal springs and geysers.
490
00:25:33,390 --> 00:25:38,280
So my job as a seismologist is to monitor Yellowstone
491
00:25:38,280 --> 00:25:40,110
for seismic activity.
492
00:25:40,110 --> 00:25:42,900
We have about 40 seismometers running
493
00:25:42,900 --> 00:25:45,030
in Yellowstone all the time.
494
00:25:45,030 --> 00:25:46,710
So this is a map of all the earthquakes
495
00:25:46,710 --> 00:25:49,080
that have been located in the Yellowstone region
496
00:25:49,080 --> 00:25:51,120
from the '70s to the present.
497
00:25:51,120 --> 00:25:52,980
And what you can see here, the green outline here,
498
00:25:52,980 --> 00:25:54,900
this is Yellowstone National Park.
499
00:25:54,900 --> 00:25:57,300
Each one of these dots represents one earthquake.
500
00:25:57,300 --> 00:25:59,430
There's over 50,000 earthquakes on this map
501
00:25:59,430 --> 00:26:02,620
that we've located from the '70s to now.
502
00:26:02,620 --> 00:26:04,920
(light music)
503
00:26:04,920 --> 00:26:06,630
The seismometers record
504
00:26:06,630 --> 00:26:08,643
even the faintest ground movement.
505
00:26:10,920 --> 00:26:12,780
So we can use data recorded on these instruments
506
00:26:12,780 --> 00:26:13,980
to find out that, you know,
507
00:26:13,980 --> 00:26:16,290
about five kilometers beneath our feet in Yellowstone,
508
00:26:16,290 --> 00:26:17,310
there's a magma reservoir.
509
00:26:17,310 --> 00:26:19,010
There's molten material beneath us
510
00:26:19,950 --> 00:26:23,430
that's feeding all the things that we see in Yellowstone.
511
00:26:23,430 --> 00:26:25,920
The thermal features, the earthquakes,
512
00:26:25,920 --> 00:26:26,850
the ground deformation,
513
00:26:26,850 --> 00:26:29,040
that's what's the source of all that,
514
00:26:29,040 --> 00:26:31,230
all that change that we can see.
515
00:26:31,230 --> 00:26:34,140
Yellowstone's intricate network of hot springs
516
00:26:34,140 --> 00:26:37,803
is fueled by magma stored below Earth's surface.
517
00:26:38,640 --> 00:26:42,030
The magma is also responsible for pressure changes
518
00:26:42,030 --> 00:26:44,793
that lead to the region's numerous earthquakes.
519
00:26:46,770 --> 00:26:48,870
Three miles below the landscape,
520
00:26:48,870 --> 00:26:50,790
the molten rock lies in a chamber
521
00:26:50,790 --> 00:26:55,113
nearly 55 miles long and 25 miles wide.
522
00:26:55,950 --> 00:26:57,210
It is the source for one
523
00:26:57,210 --> 00:27:00,240
of the largest volcanoes in the world,
524
00:27:00,240 --> 00:27:02,943
a super volcano like Toba.
525
00:27:04,020 --> 00:27:06,450
We're standing right now on the north rim
526
00:27:06,450 --> 00:27:08,280
of the Yellowstone Caldera.
527
00:27:08,280 --> 00:27:10,650
And down there to our south, about 40 kilometers
528
00:27:10,650 --> 00:27:13,290
where you can see those snow covered mountains,
529
00:27:13,290 --> 00:27:15,540
that's the southern edge of the caldera.
530
00:27:15,540 --> 00:27:16,770
So this is a good perspective
531
00:27:16,770 --> 00:27:19,050
of just how massive this caldera is.
532
00:27:19,050 --> 00:27:20,520
And this is the reason why, you know,
533
00:27:20,520 --> 00:27:22,560
a lot of people don't realize,
534
00:27:22,560 --> 00:27:24,450
they're asking where the volcano is,
535
00:27:24,450 --> 00:27:26,303
but they've been in it most of the time.
536
00:27:27,450 --> 00:27:29,280
This giant chamber holds
537
00:27:29,280 --> 00:27:31,710
a huge amount of magma.
538
00:27:31,710 --> 00:27:33,270
So with the scale you can see here,
539
00:27:33,270 --> 00:27:35,760
the magma is about the same size as the caldera
540
00:27:35,760 --> 00:27:37,620
that you can see behind me right here.
541
00:27:37,620 --> 00:27:40,500
And the amount of material that's down in there
542
00:27:40,500 --> 00:27:41,333
is kind of mind-boggling.
543
00:27:41,333 --> 00:27:43,170
There's enough material down there
544
00:27:43,170 --> 00:27:44,670
that if you took all of it,
545
00:27:44,670 --> 00:27:47,320
you could fill the Grand Canyon about 10 or 11 times.
546
00:27:48,330 --> 00:27:51,480
But where does all the magma come from?
547
00:27:51,480 --> 00:27:54,210
While Toba and many other volcanoes were formed
548
00:27:54,210 --> 00:27:58,110
from subduction at the boundary of tectonic plates,
549
00:27:58,110 --> 00:28:00,003
Yellowstone is different.
550
00:28:01,560 --> 00:28:03,360
This volcano was unusual
551
00:28:03,360 --> 00:28:05,643
because it formed in the middle of a plate.
552
00:28:06,630 --> 00:28:09,870
Underneath the plate lies an anomalous hotspot,
553
00:28:09,870 --> 00:28:12,690
much warmer than the surrounding mantle.
554
00:28:12,690 --> 00:28:16,320
Plumes of magma from the hotspot rise towards the surface
555
00:28:16,320 --> 00:28:19,143
to feed the reservoir beneath Yellowstone.
556
00:28:20,520 --> 00:28:24,120
Scientists need to know if the Yellowstone super volcano
557
00:28:24,120 --> 00:28:26,580
poses a threat today.
558
00:28:26,580 --> 00:28:28,710
Humankind survive the aftermath
559
00:28:28,710 --> 00:28:31,170
of a super explosion in the past,
560
00:28:31,170 --> 00:28:33,240
but what about in the future?
561
00:28:33,240 --> 00:28:35,790
Volcanologist Dr. Madison Myers
562
00:28:35,790 --> 00:28:38,250
is investigating Yellowstone's past
563
00:28:38,250 --> 00:28:40,650
to learn more about the destructive power
564
00:28:40,650 --> 00:28:43,923
this volcano might be capable of.
565
00:28:43,923 --> 00:28:44,940
(light music)
566
00:28:44,940 --> 00:28:48,750
A volcanologist job essentially is to look at rocks,
567
00:28:48,750 --> 00:28:50,640
try to understand what happened in the past,
568
00:28:50,640 --> 00:28:54,060
and then try to figure out what could happen in the future.
569
00:28:54,060 --> 00:28:55,860
Yellowstone's rocks reveal
570
00:28:55,860 --> 00:28:58,410
that the volcano erupted multiple times
571
00:28:58,410 --> 00:29:00,480
over millions of years.
572
00:29:00,480 --> 00:29:02,730
Most eruptions were minor,
573
00:29:02,730 --> 00:29:05,160
but two were devastating.
574
00:29:05,160 --> 00:29:07,830
So by studying the deposits around Yellowstone,
575
00:29:07,830 --> 00:29:09,510
we're able to tell that there was actually
576
00:29:09,510 --> 00:29:12,330
two, large, super eruptions that occurred here.
577
00:29:12,330 --> 00:29:14,550
The oldest at 2.1 million years ago
578
00:29:14,550 --> 00:29:16,020
is the Huckleberry Ridge Tuff,
579
00:29:16,020 --> 00:29:18,540
wrapped around 2,500 cubic kilometers,
580
00:29:18,540 --> 00:29:22,110
and then the younger one, at 630,000 years ago,
581
00:29:22,110 --> 00:29:23,340
is the Lava Creek Tuff,
582
00:29:23,340 --> 00:29:25,080
which formed the Yellowstone Caldera,
583
00:29:25,080 --> 00:29:26,100
which we can see here.
584
00:29:26,100 --> 00:29:28,750
We're actually sitting on the caldera edge right now.
585
00:29:30,180 --> 00:29:33,450
Nearly 250 cubic miles of material
586
00:29:33,450 --> 00:29:36,783
was ejected by Yellowstone's most recent eruption.
587
00:29:37,650 --> 00:29:40,680
Ignimbrites, ash, and quartz crystals
588
00:29:40,680 --> 00:29:42,723
are still found throughout the area.
589
00:29:43,680 --> 00:29:46,200
These remnants of the enormous event
590
00:29:46,200 --> 00:29:49,410
show that it dwarfed the most violent catastrophes
591
00:29:49,410 --> 00:29:50,613
in modern history.
592
00:29:51,540 --> 00:29:53,040
Well, if you think of Mount St. Helens,
593
00:29:53,040 --> 00:29:54,930
Mount St. Helens was this enormous,
594
00:29:54,930 --> 00:29:56,940
extremely impactful volcano.
595
00:29:56,940 --> 00:30:00,810
And you can imagine just the plume going up,
596
00:30:00,810 --> 00:30:03,750
the devastation that happened in the forest,
597
00:30:03,750 --> 00:30:05,790
that was one cubic kilometer, right?
598
00:30:05,790 --> 00:30:08,160
So if you have the ability to expand that
599
00:30:08,160 --> 00:30:09,870
by multiplying it by a thousand,
600
00:30:09,870 --> 00:30:12,617
that's what the Lava Creek Tuff eruption was like.
601
00:30:12,617 --> 00:30:14,520
(suspenseful music)
602
00:30:14,520 --> 00:30:17,340
The landscape was in upheaval
603
00:30:17,340 --> 00:30:18,930
because of this eruption,
604
00:30:18,930 --> 00:30:22,200
and eventually the entire region collapsed.
605
00:30:22,200 --> 00:30:25,620
Now, researchers wonder if a similar explosion
606
00:30:25,620 --> 00:30:26,703
could happen again.
607
00:30:27,545 --> 00:30:29,610
(intense music)
608
00:30:29,610 --> 00:30:32,670
There's no reason to think that it couldn't happen again.
609
00:30:32,670 --> 00:30:35,640
We do have like a chain of essentially volcanic centers
610
00:30:35,640 --> 00:30:37,020
leading up to this that have shown
611
00:30:37,020 --> 00:30:39,330
that multiple, large eruptions have happened.
612
00:30:39,330 --> 00:30:41,820
So it is very feasible that in the future
613
00:30:41,820 --> 00:30:43,759
you might have a super eruption.
614
00:30:43,759 --> 00:30:44,592
(light music)
615
00:30:44,592 --> 00:30:46,290
To potentially forecast
616
00:30:46,290 --> 00:30:48,060
how much warning time we'd have
617
00:30:48,060 --> 00:30:50,073
before a catastrophic eruption.
618
00:30:50,910 --> 00:30:55,293
Dr. Myers examines the ancient volcanic deposits for clues.
619
00:30:57,690 --> 00:30:59,940
So with the rocks that we take back to the lab,
620
00:30:59,940 --> 00:31:02,520
we're able to look into them and kind of dissect
621
00:31:02,520 --> 00:31:04,380
what their histories were.
622
00:31:04,380 --> 00:31:07,560
So we use different instrumentation to try to image it,
623
00:31:07,560 --> 00:31:10,320
try to get a picture of what was happening.
624
00:31:10,320 --> 00:31:12,390
She is focused on tiny crystals
625
00:31:12,390 --> 00:31:14,610
within the rocks, which are snapshots
626
00:31:14,610 --> 00:31:17,010
from the last major eruption.
627
00:31:17,010 --> 00:31:18,750
They record details,
628
00:31:18,750 --> 00:31:21,720
much like the rings inside a tree trunk.
629
00:31:21,720 --> 00:31:24,930
So, in trees, you see these different zones
630
00:31:24,930 --> 00:31:27,300
that are representing growth of the tree's life.
631
00:31:27,300 --> 00:31:28,740
The same thing's true for crystals.
632
00:31:28,740 --> 00:31:32,220
They record the different kind of phases of their life.
633
00:31:32,220 --> 00:31:34,680
And so by looking at these different zones,
634
00:31:34,680 --> 00:31:38,133
we can see, oh, this eruption actually was triggered.
635
00:31:39,810 --> 00:31:41,250
Based on her research,
636
00:31:41,250 --> 00:31:44,760
Madison is certain that geologists will be able to predict
637
00:31:44,760 --> 00:31:48,183
an impending super eruption, well, in advance.
638
00:31:49,740 --> 00:31:52,380
Volcanic systems often have warning signs,
639
00:31:52,380 --> 00:31:53,880
and the more you monitor them
640
00:31:53,880 --> 00:31:55,860
the more warning signs they often give.
641
00:31:55,860 --> 00:31:58,500
And Yellowstone is one of the best monitored volcanoes
642
00:31:58,500 --> 00:31:59,370
in the United States.
643
00:31:59,370 --> 00:32:01,680
So it's gonna give off plenty of warning signs,
644
00:32:01,680 --> 00:32:04,020
likely for the same kind of decades
645
00:32:04,020 --> 00:32:06,540
to century long time skills that the crystals are recording,
646
00:32:06,540 --> 00:32:08,760
'cause the crystals are recording changes
647
00:32:08,760 --> 00:32:10,470
in pulses of magma coming in.
648
00:32:10,470 --> 00:32:11,880
That's an earthquake, right?
649
00:32:11,880 --> 00:32:15,420
So we would have signals that we could use
650
00:32:15,420 --> 00:32:17,880
to understand that unrest was happening.
651
00:32:17,880 --> 00:32:19,860
(suspenseful music)
652
00:32:19,860 --> 00:32:21,660
Seismologist Jamie Farrell
653
00:32:21,660 --> 00:32:24,573
is also on the lookout for these signs.
654
00:32:25,650 --> 00:32:27,810
The main things that we would look for,
655
00:32:27,810 --> 00:32:29,790
the main things that we monitor for here in Yellowstone
656
00:32:29,790 --> 00:32:31,893
are increased seismic activity,
657
00:32:32,730 --> 00:32:34,710
increased ground deformation,
658
00:32:34,710 --> 00:32:38,130
and then changes in the gas output in Yellowstone.
659
00:32:38,130 --> 00:32:40,080
So we would look for those three things.
660
00:32:40,080 --> 00:32:41,640
If one of those things changes,
661
00:32:41,640 --> 00:32:43,740
that doesn't necessarily mean anything's outta the ordinary.
662
00:32:43,740 --> 00:32:46,560
But if all three things happen at the same time
663
00:32:46,560 --> 00:32:48,270
and they're all pointing to the same thing,
664
00:32:48,270 --> 00:32:50,310
then we would know, okay, maybe magma's moving up
665
00:32:50,310 --> 00:32:51,630
into the shallow crest.
666
00:32:51,630 --> 00:32:53,280
It might make it to the surface.
667
00:32:53,280 --> 00:32:54,940
Let's look at this deeper.
668
00:32:54,940 --> 00:32:55,773
(intense music)
669
00:32:55,773 --> 00:32:56,673
The scientists know
670
00:32:56,673 --> 00:32:59,640
that if a super eruption does occur,
671
00:32:59,640 --> 00:33:02,790
it would have catastrophic consequences.
672
00:33:02,790 --> 00:33:03,900
Yeah, another super eruption
673
00:33:03,900 --> 00:33:05,160
would change our world completely.
674
00:33:05,160 --> 00:33:08,160
I mean, it would have at least decades of impact.
675
00:33:08,160 --> 00:33:09,630
One thing we would definitely have,
676
00:33:09,630 --> 00:33:10,830
we'll have a big explosion.
677
00:33:10,830 --> 00:33:14,190
You know, it would eject a lot of material, a lot of ash.
678
00:33:14,190 --> 00:33:16,350
We would have a lot of asphalt in the surrounding areas.
679
00:33:16,350 --> 00:33:19,830
We've had of pyroclastic flows coming out from the plume,
680
00:33:19,830 --> 00:33:22,770
devastating the area around here in the park.
681
00:33:22,770 --> 00:33:24,690
The effects of such an eruption
682
00:33:24,690 --> 00:33:27,153
would reach far beyond North America.
683
00:33:28,800 --> 00:33:30,690
These large volume eruptions
684
00:33:30,690 --> 00:33:33,060
are gonna have devastating consequences.
685
00:33:33,060 --> 00:33:36,452
They shoot these huge plumes way up into the stratosphere
686
00:33:36,452 --> 00:33:39,420
that likely cycle the world multiple times,
687
00:33:39,420 --> 00:33:41,550
leading to this global winter
688
00:33:41,550 --> 00:33:43,980
where vegetation's going to struggle,
689
00:33:43,980 --> 00:33:45,480
animals will struggle,
690
00:33:45,480 --> 00:33:47,820
and so it would be a completely devastating
691
00:33:47,820 --> 00:33:49,380
and life altering event.
692
00:33:49,380 --> 00:33:51,600
I would say that it's probably one of the top things
693
00:33:51,600 --> 00:33:53,223
that could threaten humankind.
694
00:33:54,300 --> 00:33:56,850
It would be a global catastrophe,
695
00:33:56,850 --> 00:33:59,550
far greater than the Toba eruption,
696
00:33:59,550 --> 00:34:02,883
that would endanger all life on Earth once again.
697
00:34:05,670 --> 00:34:06,503
(theatrical music)
698
00:34:06,503 --> 00:34:09,600
But life on our planet isn't just threatened by disasters
699
00:34:09,600 --> 00:34:11,853
created by Earth's processes.
700
00:34:12,870 --> 00:34:16,590
In 2013, residents of Chelyabinsk, Russia
701
00:34:16,590 --> 00:34:18,870
witnessed a dramatic event.
702
00:34:18,870 --> 00:34:23,283
The sky blazed as an asteroid entered Earth's atmosphere.
703
00:34:24,210 --> 00:34:27,030
Caught on dash cams and surveillance videos,
704
00:34:27,030 --> 00:34:28,533
people were stunned.
705
00:34:29,388 --> 00:34:31,777
(light music)
706
00:34:31,777 --> 00:34:33,750
Frascati, Italy.
707
00:34:33,750 --> 00:34:37,530
The European Space Agency is one of the few organizations
708
00:34:37,530 --> 00:34:40,233
dedicated to monitoring space hazards.
709
00:34:41,940 --> 00:34:45,180
Dr. Richard Moissl, head of Planetary Defense,
710
00:34:45,180 --> 00:34:48,573
has been studying the Chelyabinsk event in detail.
711
00:34:50,430 --> 00:34:52,620
We know that the impactor had about
712
00:34:52,620 --> 00:34:54,990
a diameter of 20 meters.
713
00:34:54,990 --> 00:34:57,780
The asteroid approached with an estimated velocity
714
00:34:57,780 --> 00:35:00,840
of over 66,000 kilometers a second.
715
00:35:00,840 --> 00:35:03,210
The damage went into the millions.
716
00:35:03,210 --> 00:35:05,790
Unfortunately, many people got hurt.
717
00:35:05,790 --> 00:35:09,810
In total, there were more than 1,400 people injured.
718
00:35:09,810 --> 00:35:13,380
But we can consider this even a lucky event
719
00:35:13,380 --> 00:35:17,160
because the energy deposited in the atmosphere
720
00:35:17,160 --> 00:35:20,220
was several times that of the Hiroshima bomb.
721
00:35:20,220 --> 00:35:21,450
(light music)
722
00:35:21,450 --> 00:35:24,090
Things could have been much worse.
723
00:35:24,090 --> 00:35:26,490
With a diameter of 65 feet,
724
00:35:26,490 --> 00:35:29,490
this asteroid is tiny compared to those
725
00:35:29,490 --> 00:35:31,593
that impacted Earth in the past.
726
00:35:33,870 --> 00:35:37,590
66 million years ago, an asteroid with a diameter
727
00:35:37,590 --> 00:35:39,813
of around six miles struck Earth.
728
00:35:40,830 --> 00:35:43,800
Instantly, the energy of billions of nuclear weapons.
729
00:35:43,800 --> 00:35:47,160
was released when the impactor vaporized,
730
00:35:47,160 --> 00:35:49,713
melting the bedrock into molten plasma.
731
00:35:51,210 --> 00:35:55,230
The resulting thermal radiation, earthquakes, and tsunamis
732
00:35:55,230 --> 00:35:57,090
wreaked havoc around the globe
733
00:35:57,090 --> 00:35:59,460
on an unprecedented scale
734
00:35:59,460 --> 00:36:02,190
and was one of the most disastrous events
735
00:36:02,190 --> 00:36:04,140
in Earth's history.
736
00:36:04,140 --> 00:36:07,440
The impact caused a chain reaction of horrific events
737
00:36:07,440 --> 00:36:11,880
that caused the extinction of 75% of all species
738
00:36:11,880 --> 00:36:13,230
alive at the time.
739
00:36:13,230 --> 00:36:15,481
(asteroid explodes)
740
00:36:15,481 --> 00:36:18,398
(dinosaur roaring)
741
00:36:21,641 --> 00:36:24,224
(air swooshes)
742
00:36:25,800 --> 00:36:29,793
Asteroids remain among the biggest threats to our planet.
743
00:36:31,260 --> 00:36:32,850
There's a lot of stuff out there.
744
00:36:32,850 --> 00:36:36,000
Today, we know more than a million asteroids already
745
00:36:36,000 --> 00:36:37,350
which are out there.
746
00:36:37,350 --> 00:36:40,830
But of these, 30,000 are especially interesting
747
00:36:40,830 --> 00:36:42,240
because they come close to Earth.
748
00:36:42,240 --> 00:36:44,250
That's what we call the near-Earth objects,
749
00:36:44,250 --> 00:36:46,770
and these are the ones of particular interest to us.
750
00:36:46,770 --> 00:36:49,470
We track them as much as we can,
751
00:36:49,470 --> 00:36:51,420
but we don't only determine their orbits
752
00:36:51,420 --> 00:36:52,950
where they are at the moment.
753
00:36:52,950 --> 00:36:56,820
We determine their paths up to 100 years into the future
754
00:36:56,820 --> 00:36:58,590
and check if they actually will become
755
00:36:58,590 --> 00:36:59,883
a danger to us one day.
756
00:37:01,260 --> 00:37:03,630
Fortunately, most of these asteroids
757
00:37:03,630 --> 00:37:06,843
are only a few inches to a few yards in diameter.
758
00:37:08,160 --> 00:37:10,410
Every day, more than 100 tons
759
00:37:10,410 --> 00:37:13,170
of harmless debris and dust from space
760
00:37:13,170 --> 00:37:14,733
bombard our planet.
761
00:37:15,670 --> 00:37:17,850
(asteroid whooshes)
762
00:37:17,850 --> 00:37:22,850
They usually burn up in the atmosphere as shooting stars,
763
00:37:23,280 --> 00:37:25,200
creating a spectacle, nothing more.
764
00:37:25,200 --> 00:37:28,800
But once in a while, asteroids come along
765
00:37:28,800 --> 00:37:31,563
which are bigger in size and do pose a danger.
766
00:37:32,910 --> 00:37:36,330
This is what happened in Tunguska,
767
00:37:36,330 --> 00:37:39,510
a remote forested region of Siberia.
768
00:37:39,510 --> 00:37:41,310
A monster explosion caused one
769
00:37:41,310 --> 00:37:44,493
of the most devastating impacts in human history.
770
00:37:45,660 --> 00:37:48,270
On the morning of June 30th 1908,
771
00:37:48,270 --> 00:37:51,180
a massive event shook the landscape.
772
00:37:51,180 --> 00:37:53,520
Brilliant lights illuminated the sky
773
00:37:53,520 --> 00:37:56,523
and were seen as far away as the UK.
774
00:37:57,930 --> 00:38:00,300
The first scientific expedition
775
00:38:00,300 --> 00:38:02,610
to examine the resulting damage
776
00:38:02,610 --> 00:38:05,853
didn't occur until 1927.
777
00:38:07,620 --> 00:38:09,810
Footage taken at the location
778
00:38:09,810 --> 00:38:12,123
shows widespread destruction.
779
00:38:13,050 --> 00:38:15,990
Over 80 million trees were flattened
780
00:38:15,990 --> 00:38:20,990
and a 1,250 square mile area of forest was destroyed.
781
00:38:22,860 --> 00:38:24,720
But despite the devastation,
782
00:38:24,720 --> 00:38:27,480
there was no sign of an impact crater
783
00:38:27,480 --> 00:38:29,670
and scientists could not determine
784
00:38:29,670 --> 00:38:31,953
where the asteroid struck.
785
00:38:35,940 --> 00:38:38,010
So there has been no conclusive answer
786
00:38:38,010 --> 00:38:40,380
to what caused the Tunguska event to date.
787
00:38:40,380 --> 00:38:44,020
But the most probable explanation still remains to date
788
00:38:45,150 --> 00:38:48,600
an impact of a very porous body with low density
789
00:38:48,600 --> 00:38:52,530
that caused an airburst of the magnitude
790
00:38:52,530 --> 00:38:53,798
that we observe here.
791
00:38:53,798 --> 00:38:55,140
(asteroid swooshes)
792
00:38:55,140 --> 00:38:58,410
When an asteroid enters Earth's atmosphere,
793
00:38:58,410 --> 00:39:00,483
it creates an airburst.
794
00:39:01,410 --> 00:39:04,470
Because the impactor travels at high velocity,
795
00:39:04,470 --> 00:39:06,660
pressure builds in front of it
796
00:39:06,660 --> 00:39:11,280
until the asteroid bounces off its target or breaks apart.
797
00:39:11,280 --> 00:39:13,650
When this happens, energy is released
798
00:39:13,650 --> 00:39:16,167
in a huge burst of light and heat,
799
00:39:16,167 --> 00:39:17,550
(asteroid explodes)
800
00:39:17,550 --> 00:39:21,123
which causes immense destruction on the ground surface.
801
00:39:22,560 --> 00:39:26,580
Luckily, this event didn't cause any confirmed casualties.
802
00:39:26,580 --> 00:39:28,680
But it would be completely different story
803
00:39:28,680 --> 00:39:30,210
if something like this were to happen
804
00:39:30,210 --> 00:39:33,900
over a density populated area or a big city.
805
00:39:33,900 --> 00:39:35,730
At the European Space Agency,
806
00:39:35,730 --> 00:39:38,430
the Planetary Defense Team regularly simulates
807
00:39:38,430 --> 00:39:41,820
emergency scenarios so they will be prepared
808
00:39:41,820 --> 00:39:44,493
if an asteroid threat becomes a reality.
809
00:39:45,870 --> 00:39:47,070
We've taken the data
810
00:39:47,070 --> 00:39:49,230
from the Tunguska simulations
811
00:39:49,230 --> 00:39:51,480
and projected them right over Manhattan.
812
00:39:51,480 --> 00:39:54,210
The software now shows us the impact effects
813
00:39:54,210 --> 00:39:55,577
at the location.
814
00:39:55,577 --> 00:39:56,880
(intense music)
815
00:39:56,880 --> 00:39:58,860
A Tunguska-sized asteroid
816
00:39:58,860 --> 00:40:01,050
about 160 feet wide
817
00:40:01,050 --> 00:40:03,360
would demolish the metropolis
818
00:40:03,360 --> 00:40:07,453
even after it broke apart 20 miles above Earth.
819
00:40:07,453 --> 00:40:08,944
(intense music)
820
00:40:08,944 --> 00:40:10,230
(asteroid explodes)
821
00:40:10,230 --> 00:40:12,750
The blast wave would shatter all windows,
822
00:40:12,750 --> 00:40:14,490
would damage all buildings not built
823
00:40:14,490 --> 00:40:17,890
out of reinforced concrete to a considerable degree.
824
00:40:17,890 --> 00:40:18,723
(asteroids exploding)
825
00:40:18,723 --> 00:40:20,490
Many people would die
826
00:40:20,490 --> 00:40:23,013
and millions would be affected and injured.
827
00:40:24,660 --> 00:40:26,550
The blazing heat would destroy
828
00:40:26,550 --> 00:40:31,200
block after block, affecting most of New York City.
829
00:40:31,200 --> 00:40:33,090
An asteroid strike like this
830
00:40:33,090 --> 00:40:36,759
would be a tremendous catastrophe for humankind.
831
00:40:36,759 --> 00:40:38,550
(intense music)
832
00:40:38,550 --> 00:40:40,250
These things are the reason why
833
00:40:40,250 --> 00:40:42,930
we have developed early warning systems
834
00:40:42,930 --> 00:40:45,900
so that we can notify the authorities ahead of time,
835
00:40:45,900 --> 00:40:48,150
so that in turn they can step in
836
00:40:48,150 --> 00:40:50,070
and evacuate the affected areas,
837
00:40:50,070 --> 00:40:53,250
thereby saving up to millions of lives.
838
00:40:53,250 --> 00:40:55,380
Once an asteroid is spotted,
839
00:40:55,380 --> 00:40:58,710
it is ranked and added to the asteroid risk list.
840
00:40:58,710 --> 00:41:00,780
The more Richard and his team can learn
841
00:41:00,780 --> 00:41:03,120
about the asteroid's potential path,
842
00:41:03,120 --> 00:41:06,690
the better they can determine if it will strike our planet.
843
00:41:06,690 --> 00:41:08,880
But is there anything that can be done
844
00:41:08,880 --> 00:41:12,742
if a dangerous asteroid is heading straight for Earth?
845
00:41:12,742 --> 00:41:14,358
(tense orchestral music)
846
00:41:14,358 --> 00:41:19,020
In 2021, the European Space Agency teamed with NASA
847
00:41:19,020 --> 00:41:22,260
to launch what became known as the DART mission,
848
00:41:22,260 --> 00:41:25,323
or the Double Asteroid Redirection Test.
849
00:41:26,820 --> 00:41:28,890
The goal was to prevent asteroids
850
00:41:28,890 --> 00:41:32,700
that might pose imminent threats from hitting Earth.
851
00:41:32,700 --> 00:41:35,310
The DART probe mission planned to rendezvous
852
00:41:35,310 --> 00:41:37,200
with a double system
853
00:41:37,200 --> 00:41:39,420
consisting of the asteroid Didymos
854
00:41:39,420 --> 00:41:41,790
and its moon, Dimorphos.
855
00:41:41,790 --> 00:41:45,120
This was the first attempt in space exploration
856
00:41:45,120 --> 00:41:48,930
to change the course of an astronomical body.
857
00:41:48,930 --> 00:41:50,790
The plan was to send a probe
858
00:41:50,790 --> 00:41:53,523
that would deliberately collide with the asteroid.
859
00:41:54,360 --> 00:41:55,950
During its final approach,
860
00:41:55,950 --> 00:41:59,070
DART transmitted a live stream of images
861
00:41:59,070 --> 00:42:02,520
while it was homing in on the double asteroid system.
862
00:42:02,520 --> 00:42:06,000
This is footage that has never seen it the likes before.
863
00:42:06,000 --> 00:42:09,000
And we first see how DART is closing in
864
00:42:09,000 --> 00:42:10,800
on the double asteroid system.
865
00:42:10,800 --> 00:42:13,800
Then passing by the primary, the big one,
866
00:42:13,800 --> 00:42:17,670
zooming in ever closer on the small one, on Dimorphos.
867
00:42:17,670 --> 00:42:20,670
Finally, the small one fitting the field of view
868
00:42:20,670 --> 00:42:23,907
until, bam, DART hits the asteroid,
869
00:42:23,907 --> 00:42:25,593
and the transmission ends.
870
00:42:26,610 --> 00:42:29,460
The test was successful.
871
00:42:29,460 --> 00:42:33,480
But would the technology be sufficient to save us?
872
00:42:33,480 --> 00:42:36,210
The course of the asteroid was indeed changed
873
00:42:36,210 --> 00:42:38,820
for the first time in human history.
874
00:42:38,820 --> 00:42:42,870
At first, it would only move by a fraction of a millimeter.
875
00:42:42,870 --> 00:42:46,950
But in time, if an asteroid is hit early enough
876
00:42:46,950 --> 00:42:49,260
when it still has billions of kilometers to go
877
00:42:49,260 --> 00:42:51,450
to reach its target Earth,
878
00:42:51,450 --> 00:42:54,000
a tiny distance can grow in time
879
00:42:54,000 --> 00:42:56,040
to be thousands of kilometers,
880
00:42:56,040 --> 00:42:58,920
turning a potential impact of a killer asteroid
881
00:42:58,920 --> 00:43:00,273
into a harmless flyby.
882
00:43:01,132 --> 00:43:02,580
(light music)
883
00:43:02,580 --> 00:43:04,530
Emergency strategies developed
884
00:43:04,530 --> 00:43:06,450
by the Planetary Defense Team,
885
00:43:06,450 --> 00:43:09,270
combined with ever advancing technology,
886
00:43:09,270 --> 00:43:12,510
could potentially divert a rogue asteroid
887
00:43:12,510 --> 00:43:14,973
to prevent the extinction of humankind.
888
00:43:16,830 --> 00:43:20,100
But, even if we can avert threats from space
889
00:43:20,100 --> 00:43:22,230
and from within the Earth itself,
890
00:43:22,230 --> 00:43:25,563
humans pose a growing menace to our own survival.
891
00:43:27,690 --> 00:43:30,150
Rhone Glacier, Switzerland.
892
00:43:30,150 --> 00:43:33,633
The Swiss Alps are a relic from the last glacial period.
893
00:43:36,090 --> 00:43:39,240
As the head of the Swiss Glacial Monitoring Network,
894
00:43:39,240 --> 00:43:40,590
Dr. Matthias Huss
895
00:43:40,590 --> 00:43:43,980
from the Swiss Federal Institute of Technology in Zurich
896
00:43:43,980 --> 00:43:46,773
regularly checks on the conditions of the glacier.
897
00:43:48,600 --> 00:43:52,110
This glacier, like all glaciers in the Alps and worldwide,
898
00:43:52,110 --> 00:43:54,030
has receded considerably.
899
00:43:54,030 --> 00:43:56,400
12 years ago, it extended all the way
900
00:43:56,400 --> 00:43:57,930
to the end of the lake here,
901
00:43:57,930 --> 00:43:59,640
which didn't exist at the time.
902
00:43:59,640 --> 00:44:01,710
Now, the glacier has retreated.
903
00:44:01,710 --> 00:44:03,873
Its thickness has decreased dramatically.
904
00:44:05,580 --> 00:44:07,380
Dr. Huss is worried about
905
00:44:07,380 --> 00:44:09,150
the extent of the changes.
906
00:44:09,150 --> 00:44:11,850
So, he has set up a monitoring system
907
00:44:11,850 --> 00:44:15,056
to record the rate of the glacial melt.
908
00:44:15,056 --> 00:44:17,556
(light music)
909
00:44:20,910 --> 00:44:23,610
We have had so-called glacial selfie sticks
910
00:44:23,610 --> 00:44:26,370
on this glacier for several years now.
911
00:44:26,370 --> 00:44:29,280
They take a picture of the glacier every hour,
912
00:44:29,280 --> 00:44:32,433
which allows us to see how much it melts from day to day.
913
00:44:35,550 --> 00:44:38,550
The stick is firmly embedded in the ice.
914
00:44:38,550 --> 00:44:42,030
As the ice melts and the camera sits on the surface,
915
00:44:42,030 --> 00:44:46,173
it looks as if the stick is growing out of the ice.
916
00:44:48,000 --> 00:44:49,530
High resolution cameras
917
00:44:49,530 --> 00:44:53,343
capture the rate at which the ice is receding.
918
00:44:54,630 --> 00:44:57,990
The glacier surface decreases a lot throughout the year.
919
00:44:57,990 --> 00:45:02,133
We lose around 20 to 26 feet of ice annually in this area.
920
00:45:03,480 --> 00:45:05,820
The Rhone Glacier is only one glacier
921
00:45:05,820 --> 00:45:07,560
that is melting.
922
00:45:07,560 --> 00:45:09,840
At the current rate, around two-thirds
923
00:45:09,840 --> 00:45:12,000
of the continent's current glacial cover
924
00:45:12,000 --> 00:45:14,553
will be lost by the end of the century.
925
00:45:17,550 --> 00:45:22,080
Natural variation in ice volume is to be expected.
926
00:45:22,080 --> 00:45:24,630
Since the beginning of the last Ice Age,
927
00:45:24,630 --> 00:45:27,930
this glacier has grown and shrunk,
928
00:45:27,930 --> 00:45:30,870
normal for such an immense body of ice.
929
00:45:30,870 --> 00:45:34,353
But, what we are seeing now is different.
930
00:45:36,690 --> 00:45:39,720
The warming we had until a few hundred years ago
931
00:45:39,720 --> 00:45:43,830
was natural due to solar radiation and other factors.
932
00:45:43,830 --> 00:45:47,433
But what we are witnessing now is manmade climate change.
933
00:45:51,600 --> 00:45:54,810
Human actions, like burning fossil fuels,
934
00:45:54,810 --> 00:45:58,050
industrialization, deforestation,
935
00:45:58,050 --> 00:46:00,840
and intensive agriculture, have all created
936
00:46:00,840 --> 00:46:03,483
a tremendous increase in greenhouse gases.
937
00:46:05,400 --> 00:46:08,610
The massive amount of CO2 we relentlessly pump
938
00:46:08,610 --> 00:46:11,370
into the atmosphere is warming our planet
939
00:46:11,370 --> 00:46:12,693
at an alarming rate.
940
00:46:13,920 --> 00:46:16,350
Global temperatures are estimated to rise
941
00:46:16,350 --> 00:46:18,660
by nearly five degrees Fahrenheit
942
00:46:18,660 --> 00:46:20,073
by the end of this century.
943
00:46:22,080 --> 00:46:26,010
Glaciers are primary indicators of climate change.
944
00:46:26,010 --> 00:46:28,440
They clearly demonstrate the consequences
945
00:46:28,440 --> 00:46:32,430
of rising temperatures as ice melts with warmer weather.
946
00:46:32,430 --> 00:46:34,050
Everyone understands that.
947
00:46:34,050 --> 00:46:36,500
You don't have to be a scientist to realize that.
948
00:46:38,460 --> 00:46:42,030
The changes seen here are impressive.
949
00:46:42,030 --> 00:46:45,150
Within a single generation, the alpine landscape
950
00:46:45,150 --> 00:46:46,713
has completely changed.
951
00:46:48,030 --> 00:46:50,610
Globally, the melting of this glacier in the Alps
952
00:46:50,610 --> 00:46:52,350
may seem insignificant.
953
00:46:52,350 --> 00:46:54,810
However, if all glaciers worldwide
954
00:46:54,810 --> 00:46:57,480
along with the large polar ice caps melt,
955
00:46:57,480 --> 00:46:59,133
sea levels will rise.
956
00:47:00,420 --> 00:47:03,120
This poses one of the greatest long-term threats
957
00:47:03,120 --> 00:47:06,363
to life on Earth and to the way we currently live.
958
00:47:08,850 --> 00:47:11,280
Since industrialization began,
959
00:47:11,280 --> 00:47:13,830
global warming has caused sea levels to rise
960
00:47:13,830 --> 00:47:16,110
by nearly eight inches.
961
00:47:16,110 --> 00:47:17,730
By the end of this century,
962
00:47:17,730 --> 00:47:19,713
they could rise over three feet.
963
00:47:21,390 --> 00:47:23,910
Mega cities like Jakarta, Indonesia
964
00:47:23,910 --> 00:47:26,370
could be swallowed by the sea.
965
00:47:26,370 --> 00:47:28,650
Coastal settlements would be lost
966
00:47:28,650 --> 00:47:32,343
and even further inland, the severe effects would be felt.
967
00:47:34,920 --> 00:47:38,250
We're talking about heavy rainfall, floods.
968
00:47:38,250 --> 00:47:40,830
We're talking about droughts and heat waves
969
00:47:40,830 --> 00:47:43,710
that will become much more frequent in the future.
970
00:47:43,710 --> 00:47:47,250
All of this renders regions uninhabitable.
971
00:47:47,250 --> 00:47:49,050
We will witness climate refugees,
972
00:47:49,050 --> 00:47:51,930
and perhaps wars over water in the future
973
00:47:51,930 --> 00:47:56,130
as a result of very, very significant consequences,
974
00:47:56,130 --> 00:47:57,960
far reaching consequences
975
00:47:57,960 --> 00:48:00,573
that humanity must somehow get control of.
976
00:48:03,540 --> 00:48:06,630
Global warming will cause natural disasters
977
00:48:06,630 --> 00:48:11,310
like hurricanes, floods, and droughts to increase.
978
00:48:11,310 --> 00:48:14,400
Fresh water is becoming increasingly scarce,
979
00:48:14,400 --> 00:48:16,143
and famine is on the rise.
980
00:48:18,180 --> 00:48:22,233
Forest migration and unrest leading to wars could result.
981
00:48:23,070 --> 00:48:27,030
Between 3.3 and 3.6 billion people on Earth
982
00:48:27,030 --> 00:48:30,750
are extremely vulnerable to the negative consequences
983
00:48:30,750 --> 00:48:32,703
brought about by climate change.
984
00:48:35,910 --> 00:48:39,180
The problem lies primarily in the extreme velocity
985
00:48:39,180 --> 00:48:42,480
at which we can now observe manmade climate change.
986
00:48:42,480 --> 00:48:44,460
We are transitioning from one dimension
987
00:48:44,460 --> 00:48:46,380
to a completely different one
988
00:48:46,380 --> 00:48:47,793
within a generation or two.
989
00:48:49,020 --> 00:48:51,810
Adapting to this is incredibly difficult
990
00:48:51,810 --> 00:48:53,730
and represents the greatest challenge
991
00:48:53,730 --> 00:48:56,433
humanity will be facing in the coming decades.
992
00:48:59,820 --> 00:49:03,480
Yet, Dr. Huss remains optimistic.
993
00:49:03,480 --> 00:49:06,090
While humans are the cause of this problem,
994
00:49:06,090 --> 00:49:09,420
we also have the tools to create the solution,
995
00:49:09,420 --> 00:49:10,923
if we act soon.
996
00:49:13,590 --> 00:49:16,080
We actually have a choice now.
997
00:49:16,080 --> 00:49:19,290
We still have it in our hands to set the direction
998
00:49:19,290 --> 00:49:21,000
in which our planet is moving
999
00:49:21,000 --> 00:49:23,793
and whether it will remain habitable in the future.
1000
00:49:26,580 --> 00:49:30,570
We still have a few decades to make this course correction,
1001
00:49:30,570 --> 00:49:34,473
and I hope that we can achieve this as a global community.
1002
00:49:37,620 --> 00:49:40,980
Earth now has more than 8 billion people,
1003
00:49:40,980 --> 00:49:44,160
and collectively, our existence has caused the demise
1004
00:49:44,160 --> 00:49:46,320
of many other species.
1005
00:49:46,320 --> 00:49:48,960
The current rate of extinction is higher
1006
00:49:48,960 --> 00:49:51,630
than any of those seen during the last five,
1007
00:49:51,630 --> 00:49:53,643
major mass extinctions.
1008
00:49:54,780 --> 00:49:57,450
If Earth continues to grow warmer,
1009
00:49:57,450 --> 00:50:00,000
this rate will accelerate.
1010
00:50:00,000 --> 00:50:03,840
Some scientists believe that we are already experiencing
1011
00:50:03,840 --> 00:50:06,180
a sixth mass extinction,
1012
00:50:06,180 --> 00:50:10,143
and it is one that might eventually include humankind.
1013
00:50:11,040 --> 00:50:15,000
But as Earth stewards, we can learn from the past
1014
00:50:15,000 --> 00:50:19,200
while using technology now and in the future
1015
00:50:19,200 --> 00:50:21,480
to protect our planetary home
1016
00:50:21,480 --> 00:50:24,423
for ourselves and other species.
1017
00:50:26,130 --> 00:50:29,070
The future of life on our fateful planet
1018
00:50:29,070 --> 00:50:32,070
now rests in our hands.
1019
00:50:32,070 --> 00:50:36,405
It's up to us whether we are a part of it.
1020
00:50:36,405 --> 00:50:38,032
(cinematic music)
1021
00:50:38,032 --> 00:50:40,090
(water splashing)
1022
00:50:40,090 --> 00:50:43,007
(theatrical music)
1023
00:51:00,154 --> 00:51:03,904
(theatrical music continues)
1024
00:51:20,188 --> 00:51:23,938
(theatrical music continues)