Catastrophe - Episode 4 - Asteroid Impact

this city the people in it in fact everyone in the world are only here by chance you me an all life on earth inherited the world after a series of disasters wiped out 99% of all species but if it hadn't been for those catastrophes then none of us would be here at all 65 million years ago an asteroid the size of Mount Everest smashed into the earth at 60 times the speed of sound it unleashed a series of events that wiped out 70% of all species including the dinosaurs this is the story of that great impact we tend to think of evolution as a calm and orderly progression from one species to the next but scientists have made discoveries that turn that whole notion completely on its head they see it as a much more violent process and one surprisingly shaped by chance in this series we're looking at the theories on major global disasters that nearly stopped evolution in its tracks to put Earth's violent history in perspective think of it like a clock each minute represents three million years and midnight the planet formed just minutes later a cataclysmic collision created the moon at 8:27 p.m. the planet plunged into a killer ice age and at 10:40 p.m. massive volcanic eruptions wiped out 95% of all species on earth finally at 11:38 p.m. the earth suffered a catastrophic cosmic impact a strike so large it blasted billions of tons of debris into the atmosphere and set the whole planet ablaze it triggered a chain of events that wiped out 70% of all life on Earth including the dinosaurs now 65 million years later scientists are piecing together the story of the day the dinosaurs died this is the Red Deer River Valley in the Canadian Badlands paleontologist Phil curry is here to investigate one of the most significant events in Earth's history the last great mass extinction it was an event that changed the course of evolution and led directly to the emergence of mammals and eventually humans Harry is hunting for the fossilized remains of the last of the dinosaurs a wonderful thing about these Badlands is you know almost anywhere and at specific levels you can actually find bone and great abundance this was picked up in less than 10 minutes and we have things like whole claws sometimes whole teeth this bone which is very very dense and hollow is from one of the carnivorous dinosaurs so we can see that this is something perhaps like Velociraptor basically along the Red Deer River we have 10 million years of dinosaurian history represented and at each level there are different dinosaurs these layers of rock represent millions of years of evolution the deeper the layer the further back it is in time well as you can see the rock here is actually in layers so we have layer of sand stone here layer mud stone below it layers of coal layers of silt stone layers of different things but they're all laid down horizontally one on top of the other in a way it's kind of like looking at a book from the back forwards each one of these pages of course represents a different page in the history of the earth somewhere in these layers like clues to the death of the dinosaurs several feet below the surface is a layer that's intrigued scientists for generations the Cretaceous tertiary or KT boundary this is exactly what I was looking for this is where we have the cretaceous-tertiary boundary and this is the area that for a long time we suspected would tell us something about the extinction of dinosaurs because below the layer we have dinosaurs and above the layer we have no evidence of dinosaurs at all the layer dates to 65 million years ago it marks the exact time when the dinosaurs died out so this appears to be the smoking gun this may be the layer that indicated that there was a catastrophe 65 million years ago scientists have found this same layer all around the world below it fossils from countless species above it 70% of them are gone including the dinosaurs nobody knew what caused this mass extermination until Clues emerged 5,000 miles away in southern Europe Zumaya beach northern Spain hidden within these spectacular cliffs is evidence of what scientists believe wiped the dinosaurs off the face of the earth almost 30 years ago biologist Yan Schmidt came to these very cliffs he wanted to know what killed off the dinosaurs and he thought the k/t boundary layer might be the key I started to analyze the rocks chemically approaching the KT boundary right there because I thought there must be something hidden in the rocks to tell the story how they got extinct why they disappeared what he discovered shot the scientific world the samples contained an extremely rare metal iridium that is it's rare in rocks on earth most of the Earth's iridium is trapped 4,000 miles below ground in the planets core but it is found in meteorites and asteroids and when you find a high abundance of iridium we know you have a clue to extraterrestrial material it has to come from outer space rather than from the surface of the earth he thought there could only be one conclusion a very big object must have hit the earth this was the breakthrough scientists had been looking for the yridian suggested that 65 million years ago a massive asteroid hit the planet at the exact same time as the death of the dinosaurs it was hard to believe this was a coincidence many scientists were convinced that dinosaurs have been killed by a catastrophic asteroid strike they had a plausible murder weapon but to prove it they needed to find the crime scene the site of the asteroid impact so scientists began a global search for an impact crater by measuring the worldwide spread of iridium they estimated that the crater must have been enormous around a hundred and twenty five miles in diameter the problem with the Redeem is it's it's it's within the meteorite but the meteorite is totally vaporized and the iridium is strewn out over the whole world that doesn't matter why you're here or there on the surface of the planet you find the same amount of iridium so it doesn't tell you where to look for the scientists knew there'd been an impact and they knew it was big but where on the planet had it struck they still didn't know it's 11:30 8:00 p.m. on our clock of the Earth's history 65 million years ago 70% of all life on the planet has been wiped out including the dinosaurs scientists thought this could have been the result of a cataclysmic asteroid impact but they had no real evidence of an impact big enough to cause such mayhem dan Durda is a NASA planetary scientist he specializes in the aftermath of massive cosmic impacts and where better to come than here one of the world's most spectacular asteroid craters meteor crater Arizona the impact that created it happened just 50,000 years ago it's desert location means it's one of the most perfectly preserved impact craters on the planet meteor crater is many times smaller than the one that must have been made by the asteroid that killed the dinosaurs but it does demonstrate the enormous power of even a relatively small asteroid strike it's three-quarters of a mile across debris is scattered over tens of thousands of square miles and the asteroid that did all this was just 15 metres across if a meteorite the size of a large house could make a crater of this size imagine the devastation wrought by the impact of an asteroid the size of Mount Everest that's the scale of the KT impact meteor crater was a key clue in the search for the KT strike because buried in its wall was evidence of how cosmic impacts transformed stone that immense impact released an energy our modern estimates are something on the order of one to ten megatons that's that's the scale of the largest nuclear devices we've ever detonated that immense impact excavated millions of tons of rock it it peeled open the desert like the petals of an immense flower and sprayed blocks of ejecta huge masses of rock the size of a small house for four miles in every direction out into the desert the heat and trauma of the impact was enough to transform the rock itself shocking and pulverizing individual mineral grains one sign of the violence of an impact event like this can be found in the in the rocks themselves this is Coconino sandstone it's a pretty solid sandstone it's made out of quartz grains that have been cemented together when this rock was shocked in the impact itself it was pulverized and broke those sand grains down into a much finer material almost the consistency of flour you can see here with what the impact is done to that material which has now been cemented back together in the walls of the crater very violent event that can turn rock into flour this dramatic transformation was a vital clue in the search for the location of the dinosaur strike next stop Trinidad Colorado Derr Derr is here to examine specific minerals in the KT boundary line the layer contains tiny mineral crystals similar to the ones that meteor crator as small as grains of salt its corpse but that's not why it's interesting it's interesting because something smashed it to bits so here in the in the in the the KT boundary layer this this thin white clay layer deposited we we find evidence not only of the of the iridium which was the original signature that's something funny something extraterrestrial is going on here this is that layer where we also find the shot quartz shocked quartz is normal quartz only smashed say by something extremely heavy traveling at many thousands of miles an hour only one natural phenomenon could pack enough punch to shocked quartz an asteroid impact these tiny grains are further evidence that the earth was hit by a massive asteroid at the time of the dinosaur extinction but the quartz grains also took scientists a step closer to the impact site because while the iridium was spread evenly around the boundary layer the shocked quartz wasn't as we look at the thickness of this layer here in Colorado it's about a half an inch thicker so as we move to the southeast however that layer gets thicker and thicker it grows into meters thick as we move toward the southeast toward the Caribbean and so the increasing amount of shocked quartz and the thickening of that layer as we move to the southeast toward the Caribbean is a probably a pretty good indication that that the impact occurred in that region of the world the shocked quartz pointed to an impact somewhere in the Caribbean the trouble was there was still no crater then researchers got a lucky break in 1978 Pemex the Mexican oil company were surveying the Yucatan Peninsula geophysical data from the survey and gravity field maps revealed a giant horseshoe shaped structure buried three-quarters of a mile underground beneath the sea off the Mexican coast it was huge 112 miles across 12 miles deep without her impact rings stretching to 125 miles in diameter he's seeing circles around each other like a bull's eye and the Rings define the size of a crater and it turns out that the largest ring was around 200 kilometers in size and that was exactly the size of the crater which was predicted 10 years before it was massive it was old and it had all the signs of an impact crater Vic took samples during drilling and later on the microscope we found shocked quartz by analysis of the rocks we found high abundance of iridium Chichen Itza Mexico the Mayans worshiped here a thousand years ago but the land they built on was shaped by an event 65 million years earlier the area's famous for its Mayan temples and also for its cenotes or sinkholes they form when limestone rocks get hollowed out by groundwater forming underground caverns as the cavern gets bigger its roof weakens finally it collapses leaving an open cenote to the Mayans they were sacrificial pools to us their pointers to a species killing impact crater in 1996 NASA scientist Adriana Ocampo made the connection between the cenotes and the impact she realized that the pattern of the cenotes across the region pointed to the location of the crater the discovery really worth like a detective story and this sonata ring was the last piece of the puzzle that gave credence to to the theory cenotes normally occur along lines of weakness or faults in the bedrock a camper realized that the yucatan cenotes might not be on natural fault lines the faults could have come from an impact her team studied satellite images of the Yucatan Peninsula and compared them with the oil company's maps the cenotes were arranged in a semicircular ring exactly matching that of the impact crater here we are at the ream of the Cretaceous tertiary impact crater this anata is one of many hundred senators that form a semicircle that is the surface evidence of the cretaceous that are sharing impact crater finally scientists had the exact location of the impact they could begin to build up a detailed picture of the day the asteroid struck 11:38 p.m. on our clock of Earth's history 65 million years ago a giant loaf of rock hurtled through the solar system at 45,000 miles an hour it was six miles wide and weighed about a trillion tons the size of Mount Everest and it was on a collision course with earth it smashed through the atmosphere and crashed into shallow seas at 20 times the speed of a bullet the impact released six million times more energy than the 1980 eruption of Mount Helens it set up a trail of destruction that would end with the death of the dinosaurs and you realize that at that size when that asteroid impacted the earth at the moment it started to contact the surface of the earth its trailing edge was still up there at 35,000 feet that's that's you know the altitude that jet liners are flying so we're really talking a massive object slamming into the earth the initial plume of superheated gases and debris incinerated virtually all life in the impact zone nothing within a thousand-mile radius stood a chance it literally would have been hell on earth this mountain of rock would have immediate least the contact point would have started glowing with a brilliance like like the surface of the Sun you'd probably just from the heat of the of the fireball itself coming in the flesh would have been burned off your body just from just from the intensity of that of that fireball itself but the devastation was far from over the asteroid landed in the water creating a massive tidal wave the biggest the world had ever known and if that wasn't enough red-hot debris from the impact rained back on the earth setting it ablaze things look pretty bleak for all life on Earth 65 million years ago 11:38 p.m. on the clock of Earth's history a giant asteroid plowed into the seas off Mexico's Yucatan Peninsula the impact smashed a hole right through the atmosphere a blast wave shot out at 20 times the speed of sound everything within a thousand-mile radius was incinerated on the spot but that was just the beginning the impact was so powerful it blasted billions of tons of debris into the sky setting off a chain of events that would kill off most of the life on the planet amazingly with modern technology scientists can recreate this ancient impact in the lab this is NASA's Ames Research Center just outside San Francisco planetary geologist Peter Schultz uses the facilities here to analyze what happens when an asteroid hits shallow seas just as scientists think it did 65 million years ago a substrate of sand represents the sea floor with a layer of water on top to simulate the ancient ocean what we're trying to do is to put an ocean in here we're trying to cover up the land with a shallow ocean so this is kind of like something comparable to the impact on the Yucatan 65 million years ago to simulate the asteroid he uses the NASA Ames vertical gun range so powerful it can fire a projectile at 18,000 miles per hour we should probably be able to see everything coming in exploding and then moving down range so that should be good he raises the barrel of the gun to recreate the angle of impact a steel ball stands in for the asteroid sweet okay get her saved come on kerosene that it's so cool look at this weekly super slow-motion cameras capture the impact in detail that is simply extraordinary look at that Oh okay let's see what we'll see what really happened step through this slowly oh oh let me go back look at this oh this is gorgeous Kapow it came in this direction slam dude this is now vapor was expanding heating up the atmosphere just turning it into fiery hot almost as hot as the surface of the Sun it's really intense this isn't the part that would have been lasting seconds and then would have translated all the way down range and then the crater began to form the effect of the impact amazes even shoots if we imagine this being the earth our atmosphere or if we were imagining ourselves in a jet plane 65 million years ago we'd be flying along and we would be only about less than my fingernail height the simulation shows the pattern of debris ejected from the sand and water the bullet throws up pounds of debris 65 million years ago the asteroid would have kicked up billions of tons we're talking about 500 billion tons on debris that was tossed out we saw in the experiment that this was just as these were small splatters but imagine this being the size of buildings larger than buildings the size of a small city the material thrown up from the crater reached means of up to 25,000 miles per hour some of the debris would have actually achieved escape speed and would have gone faster than the earth could hold it together to hold it in and so forming that material could have made it to the moon there may be some material sent from the earth to the moon at the point of impact the temperature hit 8,000 degrees Celsius in melted surrounding rocks and sent molten bullets flying out at supersonic speeds superheated 2000 mile an hour winds raced from the impact site this was hell on earth any creature in the impact zone would have been incinerated in an instant this is not this is worse than a horror movie this is worse than your worst dream it is very difficult to contain our imagination when it comes to thinking about something to scale Peter Schultz his recreation shows in miniature what he thinks happen next the shock wave from the impact itself actually causes the water to splash out so we've already created a shock that is the beginning of a tsunami that would have traveled all the way across the Gulf of Mexico it would have been speeding along and then crashing on the shores in Alabama and Georgia that whole region and over on the western side of Mexico the tsunami of 2004 was around 30 feet high the tsunami 65 million years ago would have been 10 times higher and thousands of times more destructive a 300-foot wall of water hurtled out from the impact zone at hundreds of miles an hour first a superheated fireball then a mega tsunami nothing within the impact zone could have survived the onslaught and on the other side of the world far from the impact many dinosaurs were also wiped out it doesn't make sense unless the aftermath of the impact was even greater than thought back at the KT boundary in Colorado dan Durda has unearthed a microscopic clue could explain how the impact triggered a global catastrophe in addition to the iridium we see in this layer and the shocked quartz grains we find small particles of soot in some cases actual charcoal but the soot we certainly see all across the layer and in all parts of the world and in fact if you add up the total amount of soot in that boundary layer it adds up to something spread globally it's something on the order of 70 billion tons of soot and that's roughly equivalent to you know all the Earth's vegetation going up in flames at once this layer of soot around the world suggests a global inferno it seems the entire planet had burst into flames not Alamos New Mexico birthplace of the atomic bomb Los Alamos scientists Kathy Plesk oh and a team at the Applied Physics Division have used supercomputers to study how an impact can incinerate a planet they've spent a million computing hours constructing a 3d simulation of the KT impact the simulation reveals for the first time how the impact would have turned the planet into a fireball it was so powerful it held over 500 billion tons of debris into the air a lot of it makes it up into the upper atmosphere and some of it even makes it out of the atmosphere and it orbits in space for a little bit and then re impacts into the surface of the earth somewhere else so this debris actually went all over the surface of the earth and as it was coming back in just like when you see in a meteor shower things heat up as they come back in to Earth's atmosphere this debris would have heated up to but there was so much of it that it would have heated up the entire atmosphere and started forest fires just from spontaneous combustion on the opposite side of the globe four hours after the impact billions of tons of superheated debris rains down on earth it buried the planet in burning rock and set the earth on fire just minutes after the impact the earth was ablaze many animals on the far side of the world that had survived the initial blast were consumed by raging wildfires for the dinosaurs anywhere on the planet would have been lethal at that point anything standing anywhere on the surface of the planet even in Antarctica or Siberia on the other side of the world would have been in real trouble it was a very very bad day for the dinosaurs incredibly against all the odds a few dinosaurs did find shelter and survived the tsunami and the global fires but even their days were numbered the final nail in the coffin was that the asteroid couldn't have struck a worse place on the planet at 11:38 p.m. on the clock of Earth's history a massive asteroid struck off the Mexican coast the impact the tsunami and the global wildfires wiped out 70% of life on the planet a few Hardy creatures did survive but they faced an even greater threat sudden and dramatic climate change the impact lofted all of this ash and debris and dust into the atmosphere blanketing the entire atmosphere with a thick opaque layer that made it night for about two to six months you couldn't see anything you couldn't have seen your hand in front of your face on the other side of the world for six months doston ash blocked out the Sun temperatures dropped like a stone and kept on dropping thanks to the impacts location if there was one place on earth that would have been a bad place to be hit it was Yucatan Peninsula the fact he is that that area had a lot of sulfur bearing minerals and that has longer term effects on the colonial climate as well as the media poisoning in the area around it the blast generated incredible heat it vaporized the rock and blasted tons of sulfur dioxide into the air it mixed with water in the atmosphere to form sulfuric acid droplets and that was a disaster the droplets were highly reflective they bounced sunlight away from the earth and sent temperatures plummeting so at first you have the dust lofted into the atmosphere which blocks out the Sun that eventually falls back as the atmosphere convects and cleans itself out but then you've still got these sulfur oxides up in the upper atmosphere which reflects sunlight and cool the planet so this prolonged the impact winter for probably another couple of years temperatures dropped by around five degrees Celsius forests destroyed by fire struggled to regenerate eventually the sulfur dioxide fell to earth and temperatures returned to normal but there was a sting in the tail the sulfur dioxide fell as acid rain first you have this six month long winter where there's no sunlight at all and then finally you get a little bit of sunlight and the plan to think oh good finally I can sprout my seeds and grow again and then the sulfur dioxide falls as acid rain and burns all the leaves off your plants the food chain collapsed the few animals that had survived the blast the tsunami the raging fires and the plummeting temperatures began to starve and the asteroids After Effects just kept on coming as global cooling made way for global warming the rocks the asteroid hit didn't just contain sulfur they also contained carbon dioxide the impact released billions of tons of greenhouse gas the equivalent of three thousand years of modern fossil fuel burning the carbon dioxide was the last effect of the impact and it hung on for centuries now warming the planet instead of cooling it so the climate is then artificially warm and not returning to normal values for several centuries after the impact carbon dioxide choked the planet temperatures increased by around 20 degrees Celsius over the next hundred years it was global warming on a fast track he was a true ecosystem collapse something that we can't even imagine at any scale today and there was no recovery it wasn't a bad summer it was devastating hundreds of years temperatures soared much of the land turns to parched desert even the hardiest plants died herbivore dinosaurs starved to death leaving the carnivores with nothing to eat they died too after 150 million years the reign of the dinosaurs ended and now here we are the supreme species on the planet but we survive and impact the size of the KT strike if something as big as the KT impact occurred now only a portion of the world would survive most of North America would be wiped out and the debris coming back to the atmosphere still would have affected them and then the longer term effects of the sudden change in climate may be oscillating from something that would be incredibly warm to the incredibly cold would have been very difficult to adjust it would have been a long time of survival frankly our prospects aren't good maybe it was a one-off of course it will happen again and this is nature this is what happens we get hit now and then and something that's as big as the KT impact should happen every 100 million years or so the bigger the impact the rarer it is so we could be waiting another 35 million years for another dinosaur killer but smaller impacts are much more frequent fifty thousand years ago a 50 meter asteroid created meteor crater in Arizona devastating an area the size of Greater London as recently as 1908 the Tunguska asteroid destroyed an area of 830 square miles impacts this big happen around every hundred years or so so where do you another one soon scientists believe that the KT impact wiped out around 70% of all species on earth but despite the death and destruction life persisted a few species not only survived they thrived with the dinosaurs out of the way new kinds of animal took center stage one was particularly successful the mammal these Hardy creatures survived the impact and the climate change one species of mammal has come to dominate practically everything us the extinction of the dinosaurs clearly cleared the way if you will emptied the world of that particular a jackal niche and gave the mammals a chance to to rise to prominence and so the extinction of the dinosaurs was sort of the the crucible of human evolution ultimately if you will we're we're here because they're not Golden Colorado Jalen Emily hunts for fossils in a layer just above the KT boundary these are the bones of some of the animals that survived the impact the fireball and the climate chaos they were small mammals the size of rodents unlikely heirs to the dinosaurs crown but the qualities that had once kept them near the bottom of the food chain now tuck them to the top starting with their small size if we compare the Katy meteorite impact to say something we can envision today such as a nuclear war the organisms that would be most likely to survive something like that are going to be the small ones the ones that can escape the surface in some way through burrowing living underground they had a much higher chance of surviving than anything that would be on the surface such as these large dinosaurs and these subterranean survivalists had another thing in their favor they want omnivores they'd eat anything the mammals that you have right after the KT impact such as this fellow right here by Akana Don these guys are generals meaning they could probably eat a variety of different things for mammals being a generalist would be very helpful after the KT boundary because there are there going to be a variety of foods on the scene and I think if you were to specialized the KT boundary might have been might have been where you met your end unlike the dinosaurs they didn't lay their eggs on the ground or raise their young in exposed nests dinosaurs lay eggs and their young developing eggs and then hatch mammals on the other hand they lay their eggs on the inside if you will and their young develop on the inside with that added protection of the mother the mother's body that probably was advantageous right after the KT boundary because those young I just had further protection from the environments the elements predators scavengers a few egg layers did make it some with the flying dinosaurs who laid their eggs in trees they evolved into birds and the primitive reptiles survived like crocodiles that buried their eggs underground along with the mammals these survivors of the catastrophe flourished after 150 million years the dinosaurs one of the most successful species that ever lived were wiped out it was the meek the burrowers and the scavengers who inherited the earth and eventually they evolved into us it's extraordinary that we may owe our very existence to one freak event a cataclysmic impact that turned our planet into a fireball and unleash deadly global chaos but if it hadn't we might not be here at all on the next catastrophe humans have arrived they too must overcome super volcanoes climate chaos and cosmic impacts but for how long you

Channel: Naked Science

Views: 1,852,009

Rating: 4.504158 out of 5

Keywords: catastrophe, asteroid, impact, meteor, strike, earth, fireball, documentary, tony, robinson, natural, disaster, planet, history, dinosaurs, species, massive, event, devastating, humans, evolution, palaeontologists, geologists, theory, cretaceous, paleogene, tertiary, boundary, extinction, fossils, iridium, metal, crust, rare, extraterrestrial, alien, crator, deadly, cataclysmic, chance, violent, clock, zone, time, killer, global, fire, hell, threat, caribbean, space, armageddon, scenario, nasa, research, aftermath, eggs, world, odds, survival

Id: hqt4US72yec

Length: 48min 8sec (2888 seconds)

Published: Tue Apr 15 2014