00:00Around 66 million years ago, dinosaurs disappeared from the Earth.
00:07Except for the ones that eventually turned into birds.
00:10Suddenly, the Earth went from the age of dinosaurs to the age of mammals.
00:15Scientists have special names for these time periods.
00:18The Cretaceous and Paleogene.
00:21And the event itself is called the KPG, or KT extinction.
00:25Picture this dramatic moment in Earth's history.
00:31It happened in the blink of an eye.
00:33A colossal asteroid as big as Mount Everest, and traveling at lightning speed, slammed into Earth.
00:42It crashed down in what we now call Southern Mexico, at a place known as the Chicxulub Crater.
00:50The impact was gigantic.
00:52Everything close to it was instantly vaporized, creating an enormous burst of energy.
00:59One of the most powerful in billions of years.
01:02Nothing could survive near the crash site.
01:05As the fiery aftermath cooled, the Earth's surface went haywire.
01:09The ground twisted and trembled, causing unbelievable earthquakes.
01:14The continent started to literally bounce.
01:17Then, the ocean floor got all stirred up, provoking the gigantic tsunami.
01:22Massive waves surged inland around the Gulf of Mexico.
01:26The debris that got blasted into the sky, started falling back to Earth like a rainstorm.
01:32Even if you weren't close to the huge pieces falling in Mexico, you'd still get hit by smaller, super-hot bits flying through the air.
01:40This heated up the atmosphere so much that forests all over the world burst into flames.
01:46The dinosaurs that lived far away from the impact area first felt a little rumble.
01:55Suddenly, the sky turned dark and gloomy, as if it was nighttime during the day.
02:00The temperatures dropped drastically, and this night during the day lasted for several weeks.
02:05And then, a blanket of ash started slowly covering the entire planet.
02:12Nasty things like carbon dioxide and bits of the sea floor started floating around in the air.
02:18This messed with the temperatures once again, making it swing wildly.
02:22The Earth was hot and cold at the same time.
02:26Nature was suffering.
02:28Forest fires, no sunlight, dangerous gases in the atmosphere.
02:32All this caused big problems for plant-eating dinosaurs.
02:37They started to vanish, and the meat-eaters were having a feast, but not for long.
02:42Soon enough, the whole food chain fell apart.
02:45This is when somewhere between 50 and 80 percent of dinosaurs said their final goodbyes.
02:51What's even sadder is that this number only counts the different types of dinosaurs.
02:56If we look at the number of individual dinosaur lives lost, it's even higher.
03:02Here's an interesting fact.
03:04If the asteroid had hit just 30 seconds earlier or later, landing in the Atlantic or Pacific rather than just off the coast of Mexico,
03:13we might have had some non-avian dinosaurs still around today.
03:17But the way it happened, the asteroid struck with a force equal to 10 billion Hiroshima's.
03:27But the only ones who made it were our mammalian ancestors.
03:31They were little shrew-like creatures who had super-fast energy systems, adaptable diets, or clever hiding spots.
03:38These early mammals survived because they were tiny and didn't need much food.
03:43We're incredibly lucky that they survived this chaos.
03:46They probably didn't even understand what was happening.
03:49They just noticed the horrible smell, huge bodies everywhere, acid rain and volcanoes erupting.
03:56So now that we know how terrible this event actually was, let's talk about a big question.
04:03Could we, modern humans, survive something like this?
04:07Well, it depends.
04:09Research from a different asteroid impact about 790,000 years ago suggests we could, but it wouldn't be easy.
04:20In that other event, a massive asteroid hit Earth once again.
04:26Just like with the Chicxulub asteroid, it sent debris into the atmosphere that covered a tenth of the planet's surface.
04:33Scientists found the pieces of that asteroid's impact, glassy rocks called tektites.
04:39They analyzed these rocks and discovered a rare mineral called rheodite.
04:44It requires extremely high pressure and temperatures to form.
04:48After studying it, scientists assumed that the impact happened in Southeast Asia, probably near Thailand.
04:55But strangely, they still haven't found the exact crater.
04:59But the main thing is, the asteroid collision did happen, and our ancestors were around during this.
05:06It surely got their attention.
05:08Even though they might not have fully grasped what was happening, the debris from this event would have caused significant climate changes.
05:15It's tough to understand how it affected our humans' evolution.
05:19All that we know is that we survived it.
05:25Currently, there are about 1,200 asteroids on a list of potential asteroid threats.
05:31But luckily, we're not in immediate danger.
05:34These asteroids are smaller than 0.6 miles in diameter.
05:38The chance of a massive asteroid like the one that hit Chicxulub between 3 to 9 miles wide striking Earth is incredibly low.
05:46Major events like this happen about once every 100 to 200 million years.
05:52On top of that, most asteroids are located between Mars and Jupiter and don't pose a threat to Earth.
06:00However, there are thousands of smaller asteroids that could potentially hit us.
06:05Most of these are small and burn up in the atmosphere, causing no harm.
06:09Some larger ones could damage buildings or cities, but wouldn't threaten all life on our blue planet.
06:15But what if a comet or a serious asteroid were to collide with Earth today?
06:23In that case, first of all, it could alter Earth's orbit.
06:27The initial energy released during an impact would cause a scorching blast wave of 570 degrees Fahrenheit.
06:35The fire would ignite vast areas of the Earth's surface.
06:38Then, it would cause a long-term impact on winter.
06:42The smoke from the megafires, along with dust and water vapor, would form a thick layer of clouds in the upper atmosphere.
06:49Just like with the dinosaur event, it would reduce sunlight and cause temperatures to drop for decades.
06:55Most plant life would die off within weeks.
06:58Large trees might survive for decades due to stored sugars and a slow metabolism.
07:03Beyond that, not much life would remain, except for microbes and smaller creatures.
07:09There are three possible strategies for humans to deal with all this mess.
07:16The best strategy is to prevent the impact in the first place.
07:19Scientists are already searching for asteroids that might cross Earth's path and discussing how to defend against them.
07:26One option is to use our biggest weapons to break up the asteroid into smaller pieces.
07:32These tiny pieces could miss Earth or burn up in our atmosphere.
07:37That would work for asteroids around 0.6 miles wide.
07:41However, this won't work for massive Chicxulub-sized asteroids.
07:45The amount of energy we'd need to destroy them exceeds our entire current arsenal.
07:51But, if we notice the asteroid early enough, maybe a series of blasts could change its course and save the day.
07:58And, according to the researchers, asteroids larger than 25 miles in size would be nearly impossible to stop with our current technology.
08:07Luckily, the chances of something like this hitting Earth are very tiny.
08:12But, okay, what if we can't prevent the impact?
08:18Here comes the second strategy.
08:20We'd have to go deep underground and create large bunkers.
08:24We know that many burrowing or deep-sea species survived the mass extinction 66 million years ago.
08:30So, these underground habitats could protect us from the direct impact effects like blasts and fires, as well as an impact winter.
08:39We'd have to harness the Earth's natural heat and live inside protective domes.
08:44They could be built in stable continental cores or deep beneath the oceans.
08:49We'd have some essential supplies like food, medicine, fuel, and water.
08:54Maybe even have some gene banks to preserve species.
08:57And the last strategy would be to copy the movie Don't Look Up and to ignore the problem until it's too late.
09:04We know that it would take collaboration among governments and institutions from many countries to design, build, and launch a series of devices into space in order to prevent the impact.
09:15If humanity will be able to pull that cooperation off, that would be a miracle.
09:21In any case, NASA takes the threat of asteroids pretty seriously.
09:25It has a well-thought-out plan involving early detection, assessment, deflection strategies, collaboration, public communication, and backup plans to protect Earth from these cosmic dangers.
09:37So we can only hope that if something like that happens, logic would prevail.
09:42We'll be back in a while.
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