- 2 hours ago
Recent shifts in global weather patterns have sparked debate over whether Earth could be entering a new period of extreme cooling. Scientists are examining unusual temperature drops, disrupted ocean currents, and changes in solar activity that challenge expectations of a warming-only future. The question now is not just how cold it might get—but whether humans are prepared for temperatures that could push the limits of survival.
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00:00Did you know that the Pleistocene era was a really important time in Earth's history?
00:06It's when the last ice age happened, and glaciers covered a lot of the planet.
00:11This period of time lasted for about 2.6 million years, and ended around 11,700 years ago.
00:18What's even cooler is that modern humans, like us, had actually evolved during this time,
00:25and had spread all over Earth before it ended.
00:29There were also some really fascinating animals that lived during the Pleistocene,
00:33like woolly mammoths and saber-toothed cats.
00:38Unfortunately, many of them went extinct at the end of this era.
00:43Earth has had some pretty wild weather patterns over the last 2.4 billion years.
00:48Although the planet is mostly ice-free, we now cycle in and out of freezing ice ages.
00:54During these glacial periods, temperatures drop, and huge areas of the planet get covered in ice.
01:01It all starts with a bit of snow, which then builds up over time.
01:06The ice reflects sunlight, making things even cooler.
01:09The result?
01:10Vast glaciers that slowly move toward the equator, changing the landscape as they go.
01:16And when the ice melts, sea levels rise again, and everything changes all over again.
01:23In total, there have been at least 5 ice ages so far.
01:28The first one was so intense that the whole planet turned into a huge snowball.
01:34Right now, we're actually in the middle of an ice age.
01:38But we're currently in a temporary warm spell that started around 11,000 years ago.
01:43These warm periods are called interglacials, and we're not quite sure how long they last.
01:50There are still massive ice sheets covering Antarctica and Greenland
01:54that hold 75% of Earth's fresh water.
01:57When these finally melt, it'll mark the end of the current ice age.
02:02Earth's temperature is affected by something called the Milankovitch cycles.
02:07Basically, the amount of heat we receive from the sun changes over years, decades, and millennia
02:14because of Earth's orbit, tilt, and axis angle.
02:19There are three different patterns to these cycles.
02:22The first is called eccentricity, which is all about the shape of our orbit.
02:27The second is obliquity, which has to do with the tilt of the Earth.
02:32And the third is precession, which is like a wobble as Earth spins.
02:38Depending on where we are in these cycles, we might experience colder or warmer temperatures.
02:44But other things, like the position of continents and the atmosphere,
02:48also play a role in our planet's fate.
02:52For example, our planet's orbit is not quite circular.
02:56It's actually a bit elongated, shaped almost like an egg.
03:01That means we're sometimes a little closer or farther from the sun, depending on the time of year.
03:06We call the point farthest away from the sun the apogee,
03:10and the closest point is the perigee.
03:13When we're at the apogee, we're moving away from the sun,
03:16but gravity eventually pulls us back toward it.
03:19This means our orbit changes a little each time,
03:23gradually shifting our position relative to the sun.
03:26Don't worry, even though the orbit changes over thousands of years,
03:30it doesn't have a big impact on our day-to-day lives.
03:35Changes in Earth's orbit can affect how much sunlight we get during the summer.
03:39This means that ice sheets in the northern hemisphere will melt less,
03:44and over time, they actually start to grow.
03:46As they grow, they reflect even more sunlight,
03:50which makes the climate even cooler and spreads the ice even farther.
03:55This process can last for a really long time,
03:58like 10,000 to 20,000 years,
04:01and eventually, it brings the planet into its next freezing season.
04:07As for the next ice age,
04:09scientists believe it might be postponed indefinitely.
04:13They've found that our human interaction with the environment,
04:16like the use of fuels,
04:18could delay the next ice age by up to 100,000 years.
04:23Earth's past ice ages were linked to the amount of solar radiation
04:27and carbon dioxide concentration in the atmosphere,
04:30and this research can even help us predict future cycles.
04:35It's amazing to think that our actions now
04:38could affect Earth's future for thousands of years to come.
04:42And while it's not really important when the next ice age begins,
04:46it's pretty cool to know that humans have the power to shape the future
04:50on a geological timescale.
04:52Ice ages have had a huge impact on our planet
04:55and human civilization.
04:57So it's fascinating to think how our actions now might change things,
05:02maybe even for the better.
05:05What did life look like on our planet during the last ice age, though?
05:09Well, North America, for instance,
05:11was home to some huge creatures.
05:13Mammoths,
05:15saber-toothed cats,
05:17giant ground sloths,
05:18and mastodons were just a few of them.
05:21And get this,
05:22even Europe had an 11-foot-tall flightless bird
05:26that weighed almost as much as a polar bear.
05:30Meanwhile, down under in Australia,
05:32there was a giant lizard
05:34that lived in all sorts of habitats during the same time period.
05:38Even though some animals from the Pleistocene era aren't around anymore,
05:43you might recognize many of those that are still around today.
05:46In Alaska, for example,
05:48you can still find brown bears,
05:51caribou,
05:51and wolves.
05:54People just like us
05:55actually lived through the ice age, too.
05:58Our species,
05:59Homo sapiens,
06:00has been around for about 300,000 years.
06:03And we've spread all around the world since then.
06:06Some of our ancestors
06:07stayed in Africa during the ice age
06:10and didn't feel the full effects of the cold.
06:12And others ventured out
06:14into other parts of the world,
06:15even into the chilly, glacial environments of Europe.
06:20Our early relatives,
06:22like the Neanderthals in Europe,
06:24and the mysterious Denisovians in Asia,
06:27were also around during this time.
06:30Although they seem to have gone extinct
06:32before the end of the ice age,
06:34it's pretty amazing to think about
06:35all those different hominids
06:37that roamed Earth during that period.
06:41What's also fascinating
06:43is how our species managed to survive the ice age,
06:46while some of our cousins didn't.
06:49Some experts believe that our adaptability,
06:52social and communication skills,
06:54and the use of tools
06:55played a huge role in it.
06:57And guess what?
06:59Humans didn't just hunker down during that time.
07:01We actually moved into new areas.
07:05Fossilized footprints found at White Sands National Park
07:08in New Mexico
07:09prove that humans have been in North America
07:12since at least 23,000 years ago.
07:15That's close to the peak of the last ice age.
07:19While a full-blown ice age might still be far away,
07:22there is a possibility of a mini-ice age coming our way.
07:27Some scientists believe that in about 10 years,
07:30we might experience a significant drop in solar activity,
07:34leading to colder temperatures in the Northern Hemisphere.
07:38This could result in conditions
07:40similar to the Little Ice Age in the late 17th century,
07:43when the Thames River in the UK froze over.
07:47While scientists aren't quite sure what caused that cooling,
07:51it's fascinating to think about the potential changes.
07:55We've done it before,
07:56so we know that humans will most likely survive
08:00the next real ice age,
08:02even if we don't manage to figure out a way
08:04to stop the next freezing era.
08:06But it would come at a high cost.
08:08All the ice that would cover most of the Northern Hemisphere
08:11would have to come from oceans,
08:14which would cause the sea level to drop.
08:16This could mean more land for some countries,
08:19but it would also create other problems.
08:23Sea levels going down might seem like a great thing at first,
08:26but actually, it could lead to some challenges.
08:30Having been covered with salt water for thousands of years,
08:33the new land might not be very fertile.
08:36This means it wouldn't be great for growing crops,
08:39and we'd have to find other ways to feed ourselves.
08:43Back when humans first started out,
08:45there weren't many of us,
08:46and there was plenty of food.
08:50Now, with over 7 billion people on the planet,
08:53it's a different story.
08:55We'll need to be resourceful
08:56to make sure everyone has enough food to eat.
09:02Put on your woolen hats,
09:04find the warmest mittens,
09:05and go buy the thickest blankets.
09:07The next ice age might be just around the corner.
09:11And the trigger is much more shocking
09:13than anyone might have expected.
09:15What's even worse?
09:16We have no control over our bitterly cold future.
09:21Earth's climate has been on a wild ride
09:24for millions of years.
09:25It's been warming up,
09:27freezing over into ice ages,
09:28then heating up again
09:29to the more normal temperatures we know today.
09:33These cycles, called quaternary ice ages,
09:36are part of a much longer pattern
09:38of global freezing and thawing.
09:40For a long time,
09:42scientists thought Earth's orbit around the sun
09:44had something to do with triggering ice ages,
09:47but figuring out exactly how was tricky.
09:50Well, new research has finally connected the dots.
09:53It shows how tiny changes in Earth's tilt,
09:56wobble, and orbit
09:57mess with the growth and melting of huge ice sheets.
10:02This is a pretty big deal
10:04because it helps scientists understand
10:06not just what happened in the past,
10:08but also what might happen
10:10to our climate in the future.
10:13Even small shifts
10:14in how Earth moves through space
10:16can have huge effects
10:17over thousands of years.
10:19These changes control
10:20how much sunlight
10:21different parts of the planet get,
10:23which affects how ice sheets grow and shrink.
10:27Earth doesn't orbit the sun
10:29in a perfect circle.
10:31It actually follows
10:32a slightly oval-shaped path.
10:34This phenomenon
10:35is called orbital eccentricity.
10:37Since the sun isn't sitting
10:39right in the center of this oval,
10:41Earth's distance from it
10:42changes throughout the year.
10:44Plus, the oval itself
10:46slowly shifts position in space over time,
10:49which is called orbital precession.
10:51On top of that,
10:53Earth's tilt, aka obliquity,
10:56also changes slightly
10:57as our planet moves around the sun.
11:01Scientists have known for a while
11:03that these orbital quirks
11:04impact our planet's climate,
11:06causing cycles of warming and cooling.
11:08As different parts of Earth's orbit shift,
11:11they change how sunlight
11:12is distributed across the planet,
11:14influencing seasons and ice ages.
11:17These Milankovitch cycles
11:19happen roughly every 20,000,
11:2140,000, 100,000,
11:23and even 400,000 years.
11:27The difficult part
11:28is to figure out
11:29how each of these orbital changes
11:31affects climate shifts.
11:33Earth's climate
11:34is a complicated system,
11:35with tons of factors
11:37influencing it at the same time.
11:40Modeling all these processes
11:41is no easy task.
11:43It needs huge computing power
11:45and a deep understanding
11:46of each factor's role
11:47in shaping our planet's past
11:49and future climate.
11:52There are two cycles
11:53that are super close
11:54to each other in timing.
11:56Precession,
11:57which happens every 21,000 years,
12:00and the second harmonic
12:02of obliquity
12:03that happens at 20,500 years.
12:06But even though they're so close,
12:08no one has been able
12:09to directly connect
12:10either of these cycles
12:11to the end of an ice age.
12:13On top of that,
12:14for the past 800,000 years,
12:17ice ages have ended
12:18every 100,000 years,
12:20and scientists still haven't figured out
12:22what causes this pattern.
12:24To get to the bottom of it,
12:26researchers turned to the deep sea.
12:28They studied changes
12:29in oxygen isotope ratios
12:31found in the tiny,
12:32fossilized shells
12:33of marine creatures.
12:35These tiny creatures
12:37live in the ocean,
12:38and their exoskeletons
12:39preserve clues
12:40about past climate,
12:42specifically,
12:43changes in ice sheets.
12:44This allowed the researchers
12:46to track the beginning
12:47and end of ice ages
12:49over the past 800,000 years.
12:52By comparing the changes
12:53in the ice sheets
12:54with Earth's orbital changes,
12:56they found an incredible pattern.
12:58The key moments
13:00when Earth moved
13:00between ice ages
13:01and warmer periods
13:02were perfectly lined up
13:04with specific relationships
13:05between precession
13:06and obliquity.
13:08It turns out
13:09that the end of an ice age
13:11called deglaciation
13:12is closely linked
13:13to the way precession
13:14and obliquity align.
13:16But it's obliquity alone
13:18that seems to trigger
13:19the start of an ice age.
13:21This discovery
13:22is the key
13:23to understanding
13:24the 100,000-year cycle
13:26of ice ages.
13:27The researchers say
13:29it was always there,
13:30just waiting to be noticed.
13:32Before the discovery,
13:34people thought the timing
13:35of ice ages
13:36was more random.
13:37But this new study
13:39shows there's
13:40a clear, predictable pattern.
13:42This means
13:43we might actually
13:44be able to predict
13:45when ice ages
13:46will happen in the future.
13:48Right now,
13:50Earth's tilt
13:50is slowly decreasing
13:51and in about 11,000 years,
13:54it'll hit its lowest point.
13:56Based on the team's calculation,
13:58the next ice age
13:59is expected to begin
14:00before then.
14:02At the same time,
14:03according to the latest reports,
14:05humans have already started
14:06pushing Earth's climate
14:08off its natural path
14:09by releasing greenhouse gases.
14:12Another thing scientists
14:14are warning about
14:15is a massive shift
14:16that's happening
14:17in the Atlantic Ocean,
14:18and it could drastically
14:19change the world's climate.
14:22The Atlantic meridional
14:23overturning circulation
14:25is a system of ocean currents
14:27that moves warm and cold water
14:29around the planet.
14:30And right now,
14:31it is showing signs
14:33of weakening.
14:34What will happen
14:35if it collapses?
14:37Freezing temperatures
14:38in Europe,
14:39extreme weather
14:40across the world,
14:41shifting monsoons,
14:43and even an Amazon rainforest
14:45drying up.
14:46And the scariest part?
14:47Some researchers say
14:49there's a 95% chance
14:51this could happen
14:51before the end
14:52of the century.
14:54Think of the AMOC
14:55like a giant conveyor belt
14:57in the ocean.
14:58Warm, salty water
15:00from the tropics
15:00flows north towards Europe,
15:02and North America.
15:04When it reaches colder areas,
15:06it cools down,
15:07becomes heavier,
15:08and sinks to the bottom
15:09of the ocean.
15:10This deep, cold water
15:12then moves southward,
15:13while fresh, warm water
15:15from the equator
15:15keeps flowing north
15:17to replace it.
15:18This system helps
15:19regulate global temperatures,
15:21keeps Europe's winters mild,
15:23and prevents the U.S. east coast
15:25from flooding.
15:26It also controls monsoon patterns
15:28that bring seasonal rain
15:30to parts of Africa,
15:31South America,
15:32and Asia.
15:33Without it,
15:35the world's climate
15:35would look completely different.
15:37Right now,
15:38melting ice from Greenland
15:40and Antarctica,
15:41along with increased rainfall
15:42and river runoff,
15:43is dumping too much freshwater
15:45into the North Atlantic.
15:48Since freshwater is lighter
15:50than seawater,
15:51it disrupts the sinking process
15:52that keeps the AMOC moving.
15:55If too much freshwater builds up,
15:57it will mess up
15:58the entire system.
15:59And once it collapses,
16:01there will be no reversing it,
16:03even if the climate
16:04later cools down.
16:06Scientists have seen
16:08two big warning signs.
16:10First of all,
16:11the warming of the ocean
16:12off the U.S. east coast,
16:13which suggests the AMOC
16:15is already slowing down.
16:18Plus, there's a cold blob of water
16:21south of Greenland.
16:22It might be a sign
16:23of the weakening
16:24of the ocean current.
16:25And that's exactly what happens
16:27before the system fails.
16:30What would happen
16:31if the AMOC fully shut down?
16:34Europe would enter an ice age.
16:37The AMOC plays an important role
16:39in keeping Europe's winters
16:41relatively mild
16:42by bringing warm water north.
16:44If this process stopped,
16:46Europe would be plunged
16:47into deep winter.
16:49London's climate would drop
16:50by 18 degrees Fahrenheit,
16:52making it feel like northern Canada.
16:55Stockholm could get up
16:57to 54 degrees Fahrenheit colder,
16:59turning it into Siberia-like conditions.
17:02And snow and ice would cover
17:04much of northern Europe year-round.
17:08Next, monsoons would shift,
17:11leading to severe droughts.
17:12The AMOC helps regulate tropical rainfall,
17:16especially in Africa,
17:17South America, and Asia.
17:19If it collapsed,
17:21West Africa's monsoons would shift
17:23or disappear,
17:24leading to devastating droughts
17:26and a massive food crisis.
17:28The Amazon rainforest could dry up,
17:31transforming into a savannah or grassland.
17:34In India and Southeast Asia,
17:37monsoon rains would disappear,
17:39and millions of people rely on them
17:41for agriculture.
17:43The U.S. East Coast
17:44could see catastrophic flooding.
17:46With the AMOC weakening,
17:48water is already piling up
17:50along the U.S. East Coast,
17:52triggering higher sea levels
17:53and stronger hurricanes.
17:55If the system shut down,
17:57sea levels would rise
17:58by up to 3.2 feet,
18:00which would make the coastal cities
18:02more vulnerable to flooding.
18:05Finally, hurricanes and extreme storms
18:08could become even more powerful
18:10because of warmer waters
18:11along the coast.
18:13Now, how close are we to disaster?
18:16For thousands of years,
18:18the AMOC has remained stable,
18:20but recent studies suggest
18:22it's weaker now than at any point
18:23in the past 1,600 years.
18:26Ocean temperatures are hitting record highs,
18:29and many researchers believe
18:31we are dangerously close
18:32to the tipping point.
18:34A study published in Nature
18:36claims that if greenhouse gas emissions
18:38continue at their current pace,
18:40there's a 95% chance
18:42that the AMOC will collapse
18:44before 2100.
18:49Divers have found something incredible
18:52in a Florida sinkhole,
18:53and it was...
18:54Stop.
18:55We need to leave a warning here.
18:56You're about to hear
18:58some pretty unusual scientific information.
19:01This knowledge will make you
19:02the smarty pants in your friend group.
19:05But there's also a risk
19:06that they'll look at you as a nerd.
19:08So perhaps it would be better for you
19:10to keep this knowledge a secret.
19:12In any case,
19:13it won't be superfluous.
19:16So, you know that scientists
19:18divide the history of our planet
19:20not only by time periods,
19:22but also by which animals lived
19:24at a certain time.
19:26For example,
19:282,000 years ago,
19:29Earth was inhabited
19:30by the blobfish,
19:31and scientists call this time
19:34the blobfish period.
19:35It's a joke.
19:36There's never been such a period,
19:37but you get the gist.
19:39The period between about
19:41419.2 million
19:43and 358.9 million years ago
19:46is called the Devonian period,
19:49or the age of fish.
19:51Do you know why?
19:52Because the first fish
19:54began to appear on the planet.
19:57The Paleogene
19:58is the period of large mammals.
20:00The famous Jurassic period
20:02marks the appearance
20:03of giant dinosaurs,
20:05which we often see
20:06in the movies.
20:07Even now,
20:08we live in a certain period
20:10called the Quaternary period.
20:12It began about
20:132.6 million years ago
20:15and continues to this day.
20:18This is the time
20:19of humans
20:20and modern animals.
20:21So the next time
20:22somebody asks you
20:23what time it is,
20:24you can just answer.
20:26It's the Quaternary period.
20:28In short,
20:29the names of these periods
20:30depend more on what creatures
20:32inhabit the planet.
20:33The longest period
20:35is the Precambrian period,
20:36or age of early life,
20:38the time when life
20:40on the planet
20:40started to form.
20:42Soft-bodied worms
20:43and jellyfish
20:44swam in the ocean,
20:45while microorganisms
20:46lived on land.
20:49This period occupies
20:50almost 90%
20:52of the Earth's
20:53total geological time.
20:55It started about
20:574.5 billion years ago
20:58and ended
21:00540 million years ago.
21:03Oh,
21:04it's still a video
21:05about divers,
21:06don't forget.
21:06We'll get back
21:07to them soon.
21:09Considering all these periods,
21:11do you know
21:11which one
21:12is of the most
21:13poorly studied?
21:15A period
21:16about which scientists
21:17know almost nothing?
21:19Especially
21:20about the animals
21:21that lived
21:22at that time.
21:23This
21:24is the
21:24Irvingtonian
21:25North American
21:26Land Mammal Age.
21:29It lasted
21:30from about
21:311.6 million
21:32to 250,000 years ago.
21:35Scientists
21:36have very few fossils
21:37that belong
21:38to this time.
21:39But recently,
21:40everything has changed.
21:43In the USA,
21:44there's the
21:45Steinhatchie River,
21:46which stretches
21:47for several tens of miles
21:49in the area
21:49of Big Bend,
21:50Florida.
21:51And just
21:52500,000 years ago,
21:53there was a sinkhole
21:55instead of the river.
21:57This is a hole
21:58in the ground
21:59that forms
21:59when water
22:00dissolves
22:00the upper rock.
22:01This rock
22:02is often limestone.
22:04Sinkholes
22:05appear in places
22:06with a lot
22:07of precipitation.
22:09Sometimes,
22:09these pits
22:10can be invisible.
22:11They look like
22:12ordinary ground,
22:13but the soil in them
22:14is loose
22:14and can easily collapse.
22:17If you accidentally
22:18get into a sinkhole,
22:19people will hear
22:20your screams
22:21and help you.
22:22But in the distant past,
22:24about half a million years ago,
22:26when animals got there,
22:27they couldn't get out
22:28of the pit,
22:29so it became
22:30their grave.
22:31After many,
22:32many years,
22:33a river appeared here,
22:34and then
22:35several fossil collectors
22:37decided to check out
22:38this place
22:39and discovered
22:39a real
22:41paleontological
22:41treasure in it.
22:43They plunged
22:44into the river
22:45and reached the bottom,
22:46there in the murky water,
22:48they saw
22:49horse teeth
22:50sticking out
22:51of the sediment.
22:52It'd be pretty scary
22:53to find for many of us,
22:54but for these guys,
22:55it was the jackpot.
22:57After the teeth,
22:58they found a hoof shaft
23:00and the skull
23:00of an unusual animal.
23:03At that moment,
23:04the collectors realized
23:05they had made
23:06a major discovery.
23:09Over the years,
23:10the sinkhole
23:11at this place
23:12had been filled
23:12with sedimentary rocks.
23:14Then,
23:15the river compacted
23:16all this mass,
23:17which made it possible
23:18to keep everything
23:19inside the sinkhole
23:20in good condition.
23:22Many animals
23:23got trapped
23:24in this pit
23:25half a million years ago,
23:26and only now
23:27have people managed
23:28to get them out.
23:29More precisely,
23:31what's left of them?
23:33Divers have found
23:34more than 500 fossils
23:35belonging to ancient animals,
23:37including unknown species.
23:39They got well-preserved bones
23:41of ancient horses,
23:43giant armadillos,
23:45sloths,
23:46and a new species
23:47of tapir.
23:49The Florida Museum
23:50examined the remains
23:52and determined
23:53that they belonged
23:53to the poorly studied
23:55Irvingtonian
23:56North American
23:56land mammal age.
23:58Most of all,
23:59scientists were struck
24:00by two finds
24:01in this collection.
24:02The first
24:04was the remains
24:04of a giant armadillo-like creature,
24:07and the second
24:08was the skull
24:09of an ancient tapir.
24:11In case you didn't know,
24:13this is a very cute
24:14pig-like mammal
24:15that has a short trunk
24:16like an elephant.
24:18Divers in Florida
24:19found the remains
24:20of a distant ancestor
24:21of this animal,
24:22which may be
24:23a new unknown species.
24:26Most of the fossils
24:28in this sinkhole
24:28belong to early
24:29Cabaline horses,
24:30a subgroup
24:31that includes
24:32modern domestic horses.
24:34The remains of horses
24:35are so well-preserved
24:36that scientists
24:37have seen signs
24:38of wear on their teeth.
24:41This will allow experts
24:42to understand
24:43the diet
24:43of these ancient creatures.
24:46We often hear news
24:47about people
24:48finding the remains
24:49of ancient animals
24:50or dinosaurs
24:51in caves, ravines,
24:52or at the bottom
24:53of lakes.
24:54But imagine
24:55if they found
24:56such remains
24:56in a museum!
24:59It all started
25:00in the early 2000s,
25:02north of the Florida
25:03border
25:03in southwest Georgia.
25:05There was a mine
25:06where workers
25:07mined clay.
25:09One day,
25:09they found the remains
25:10of some ancient animals
25:12and gave them
25:13to the Florida Museum
25:14of Natural History.
25:15There,
25:16these remains
25:17lay in storage,
25:19waiting in the wings.
25:20And then one day,
25:21some guy started
25:23sorting them up
25:23and noticed
25:24a mysterious vertebra
25:25of an unknown animal.
25:28This little grab
25:29caught the guy's attention,
25:30so he returned to it
25:32over and over again.
25:34He studied it,
25:35trying to figure out
25:36what species
25:37the bone belonged to.
25:39One day,
25:40he realized
25:41the bone belonged
25:42to an unknown
25:43extinct lizard species
25:45that looked
25:46like a tegu.
25:47You've probably seen
25:48these predatory creatures
25:49that looked
25:50like monitor lizards.
25:52so the age
25:53of the bone
25:54was about
25:5515 to 17
25:57million years old.
25:59Let's wrap up
26:00our video
26:00with something weird.
26:02You see this piece
26:03of amber-colored
26:04stone with stripes?
26:06Or is it not
26:06the stone?
26:07It looks like
26:08an ancient seashell.
26:10So right now,
26:11you're looking
26:11at the oldest fossil
26:12in history.
26:13It's a stromatolite,
26:15and its ages
26:16you won't believe it.
26:18Make a guess.
26:19100 million years?
26:21500 million years?
26:231 billion?
26:24No.
26:25This fossil
26:26is about
26:273.4 billion years old.
26:29It represents
26:30one of the earliest
26:31forms of life
26:32on Earth.
26:33No,
26:33not the stone itself.
26:35Stromatolite
26:35is just a playground.
26:37The early form
26:38of life here
26:38is these
26:39thin strips.
26:41They're called
26:42cyanobacteria,
26:43tiny,
26:44single-celled creatures.
26:46Okay,
26:47what about
26:48the remains
26:48of something bigger?
26:50Some ancient animals,
26:52for example?
26:53Meet the trilobites.
26:55They lived here
26:56during the Cambrian period,
26:57which began
26:58about 500 million years ago.
27:00This is the time
27:02when many invertebrates
27:03and fish
27:03began to appear.
27:05Their exoskeletons
27:07helped the trilobites
27:08stay remarkably well-preserved,
27:10considering their age.
27:12They were arthropods
27:13that looked like
27:14something between
27:15a spider,
27:16a scorpion,
27:17and a mutant
27:17from another galaxy.
27:20These animals
27:20lived for a very long time,
27:22and people find their remains
27:24almost all over the world.
27:26They appeared
27:27at the very beginning
27:28of the Cambrian period,
27:29survived it,
27:30and became extinct
27:31at the end
27:32of the Permian period,
27:33during the Permian mass extinction,
27:35when about 90%
27:37of all living beings
27:38were wiped off
27:39the face of the Earth.
27:41These creatures swam
27:42in open water,
27:44burrowed into the seafloor,
27:45or crawled along it.
27:46They lived like predators
27:48and scavengers.
27:50The front of the animal
27:51was protected
27:52by a strong head shield.
27:54It had crescent-shaped eyes
27:56and a calcified plate
27:57on its lower body.
27:58This plate covered
28:00its esophagus and mouth.
28:02It had several pairs of legs
28:04growing from its body.
28:05The trilobite could also curl up
28:07into a ball like a woodlouse.
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