We could also mention that every corner of the planet is covered with radioactive fallout, but at this point, it doesn't matter that much anymore.

We could also mention that every corner of the planet is covered with radioactive fallout , but at this point , it does n't matter that much anymore .


This is humanity's extinction event.


The astronauts aboard the International Space Station get to enjoy a great view for a while,

The astronauts aboard the International Space Station get to enjoy a great view for a while ,


but it's not unlikely that the spray of rocks blast into orbit will destroy the station.

but it 's not unlikely that the spray of rocks blast into orbit will destroy the station .


Those lucky enough to be in bunkers or in submarines deep below the ocean surface may survive the longest,

Those lucky enough to be in bunkers or in submarines deep below the ocean surface may survive the longest ,


before they exhaust their food supplies and have to venture out for more.

before they exhaust their food supplies and have to venture out for more .


They'll find the world a charred, freezing, radioactive wasteland.

They 'll find the world a charred , freezing , radioactive wasteland .


The planet itself doesn't care at all.

The planet itself does n't care at all .


After just a few million years, the wounds of the explosions have healed and life is thriving, arguably even more so than when humans were around.

After just a few million years , the wounds of the explosions have healed and life is thriving , arguably even more so than when humans were around .


If intelligent life emerges again, it might be able to work out what happened.

If intelligent life emerges again , it might be able to work out what happened .


When they study geology, they'll find a bizarre and very thin layer of rock covering the entire world,

When they study geology , they 'll find a bizarre and very thin layer of rock covering the entire world ,


They would probably be very, very confused.

They would probably be very , very confused .


Videos like this one take well over 1,200 hours to finish.

Videos like this one take well over 1,200 hours to finish .


Over the years, we put more and more effort into research, conversations with experts, illustration and animation, sound design and fact-checking.

Over the years , we put more and more effort into research , conversations with experts , illustration and animation , sound design and fact - checking .


For this video, we put a lot of extra work into our sources document.

For this video , we put a lot of extra work into our sources document .


You can read how we got to the information in the video, what our experts thought about it, where they disagreed with each other.

You can read how we got to the information in the video , what our experts thought about it , where they disagreed with each other .


We can take the time to do this because of you, our viewers.

We can take the time to do this because of you , our viewers .


Because you watch and share our videos, buy our posters and support us on Patreon.com.

Because you watch and share our videos , buy our posters and support us on Patreon.com .


If you like what we're doing, please consider becoming a patron or get one of the nice things we made with love.

If you like what we 're doing , please consider becoming a patron or get one of the nice things we made with love .


Thank you for watching.


What would happen if we detonated humanity's most powerful nuclear weapon at the deepest point of the ocean?

What would happen if we detonated humanity 's most powerful nuclear weapon at the deepest point of the ocean ?


For sure, tsunamis hundreds of meters high would destroy coastal cities, earthquakes would level countries, new volcanoes would bring us nuclear winter.

For sure , tsunamis hundreds of meters high would destroy coastal cities , earthquakes would level countries , new volcanoes would bring us nuclear winter .


Maybe even Earth could be ripped apart or thrown out of orbit?

Maybe even Earth could be ripped apart or thrown out of orbit ?


Currently, Earth's deepest known point is inside the Mariana Trench.

Currently , Earth 's deepest known point is inside the Mariana Trench .


The Mariana Trench is a very deep valley right at the edge of two tectonic plates that looks like an upside-down mountain.

The Mariana Trench is a very deep valley right at the edge of two tectonic plates that looks like an upside - down mountain .


It reaches a depth of about 11 kilometers, almost three times deeper than the dark grave of the Titanic.

It reaches a depth of about 11 kilometers , almost three times deeper than the dark grave of the Titanic .


It's one of the last places on Earth for humans to explore.

It 's one of the last places on Earth for humans to explore .


Pitch black and under a thousand atmospheres of pressure, it's a relatively pristine environment thanks to the absence of humans.

Pitch black and under a thousand atmospheres of pressure , it 's a relatively pristine environment thanks to the absence of humans .


We'll use the most powerful nuclear bomb humans have ever exploded, the RDS-220 hydrogen bomb, or Tsar Bomba.

We 'll use the most powerful nuclear bomb humans have ever exploded , the RDS-220 hydrogen bomb , or Tsar Bomba .


Its explosion was so massive that its shockwave traveled around the Earth three times and its mushroom cloud stretched 56 kilometers into the sky.

Its explosion was so massive that its shockwave traveled around the Earth three times and its mushroom cloud stretched 56 kilometers into the sky .


Explosions like this release such an enormous amount of energy at once that they could boil away an entire lake.

Explosions like this release such an enormous amount of energy at once that they could boil away an entire lake .


And if we set off a nuclear bomb in the Mariana Trench, that's exactly what happens.

And if we set off a nuclear bomb in the Mariana Trench , that 's exactly what happens .


Let's pull the trigger.


In the first few microseconds, the nuclear fuel undergoes its chain reaction and explodes with the power of 50 megatons of TNT.

In the first few microseconds , the nuclear fuel undergoes its chain reaction and explodes with the power of 50 megatons of TNT .


A blinding flash of light illuminates the darkness of the trench for the first time in history.

A blinding flash of light illuminates the darkness of the trench for the first time in history .


The heat of the explosion produces a cavity, a flaming bubble of water vapor, radioactive nuclei and the remains of very unlucky fish.

The heat of the explosion produces a cavity , a flaming bubble of water vapor , radioactive nuclei and the remains of very unlucky fish .


The bubble grows quickly as it vaporizes the water around it.

The bubble grows quickly as it vaporizes the water around it .


The pressure of the bubble is immense, plowing outwards as if there's nothing in the way,

The pressure of the bubble is immense , plowing outwards as if there 's nothing in the way ,


And then, almost as fast as it emerges, it stops.

And then , almost as fast as it emerges , it stops .


On the surface of the Earth, this fireball bubble would grow to 10 kilometers the second after it's detonated as the atmosphere barely puts up a fight to hold it back.

On the surface of the Earth , this fireball bubble would grow to 10 kilometers the second after it 's detonated as the atmosphere barely puts up a fight to hold it back .


But the pressure at the bottom of the Mariana Trench is enormous.

But the pressure at the bottom of the Mariana Trench is enormous .


With 11 kilometers of water overhead, being in the Mariana Trench is like being crushed by a hydraulic press from every direction.

With 11 kilometers of water overhead , being in the Mariana Trench is like being crushed by a hydraulic press from every direction .


Here a second after the detonation, our bubble is about a kilometer across, when oddly enough, it starts to shrink.

Here a second after the detonation , our bubble is about a kilometer across , when oddly enough , it starts to shrink .


The bubble overextends itself, losing pressure as it expands, until the water turns it back, recompressing it.

The bubble overextends itself , losing pressure as it expands , until the water turns it back , recompressing it .


The tug of war between the fiery death bubble and water goes back and forth a few times, the bubble shrinking and growing, until eventually the bubble loses for good.

The tug of war between the fiery death bubble and water goes back and forth a few times , the bubble shrinking and growing , until eventually the bubble loses for good .


The pressure around it is too great, and turbulent water begins to chop it up.

The pressure around it is too great , and turbulent water begins to chop it up .


It becomes something like the underwater equivalent of a mushroom cloud, as it disintegrates into many smaller hot and radioactive bubbles drifting upwards.

It becomes something like the underwater equivalent of a mushroom cloud , as it disintegrates into many smaller hot and radioactive bubbles drifting upwards .


And as our mighty destructive blast rises to the surface, it does basically nothing.

And as our mighty destructive blast rises to the surface , it does basically nothing .


No tsunami will wash away Japan or California, although boats and whales in the area might have a bad time.

No tsunami will wash away Japan or California , although boats and whales in the area might have a bad time .


The radioactive fallout will be diluted into the Pacific after a few days,

The radioactive fallout will be diluted into the Pacific after a few days ,


although a fair amount of radioactive water and salt makes it to the atmosphere, where it collects and then rains down again.

although a fair amount of radioactive water and salt makes it to the atmosphere , where it collects and then rains down again .


Even if the wind blows the fallout directly towards the Philippines, the worst of it probably happens over the oceans.

Even if the wind blows the fallout directly towards the Philippines , the worst of it probably happens over the oceans .


Clearly, the real danger comes from our explosion triggering earthquakes and volcanoes, right?

Clearly , the real danger comes from our explosion triggering earthquakes and volcanoes , right ?


The explosion would vaporize a part of the sea floor and turn a lot of sand into glass, but most of the energy goes into the water, not seismic waves.

The explosion would vaporize a part of the sea floor and turn a lot of sand into glass , but most of the energy goes into the water , not seismic waves .


Earthquakes are already quite common at tectonic plate boundaries.

Earthquakes are already quite common at tectonic plate boundaries .


And earthquakes with as much seismic energy as our bomb happen a few times a year, without triggering any sort of apocalypse.

And earthquakes with as much seismic energy as our bomb happen a few times a year , without triggering any sort of apocalypse .


But maybe it will affect the Earth's orbit?

But maybe it will affect the Earth 's orbit ?


Since no mass is taken away or added to the Earth, our orbit is completely unaffected.

Since no mass is taken away or added to the Earth , our orbit is completely unaffected .


Also, there have been well over a thousand nuclear tests in the last 70 years, and that didn't change our orbit, so why would this time be different?

Also , there have been well over a thousand nuclear tests in the last 70 years , and that did n't change our orbit , so why would this time be different ?


The strongest forces humanity can unleash are laughable compared to the forces of nature.

The strongest forces humanity can unleash are laughable compared to the forces of nature .


The planet is too big, it doesn't care.

The planet is too big , it does n't care .


So what happens to us if we detonate a nuclear weapon really deep in the ocean?

So what happens to us if we detonate a nuclear weapon really deep in the ocean ?


Did you know that every bird in our videos has an owner?

Did you know that every bird in our videos has an owner ?


More than 1,000 people have got their own bird.

More than 1,000 people have got their own bird .


It helps us explain things, clowns around in the background, or dies a horrible and avoidable death.

It helps us explain things , clowns around in the background , or dies a horrible and avoidable death .


If you want your own bird too and you want it to appear in one of our videos, you can get it at patreon.com/kurzgesagt.

If you want your own bird too and you want it to appear in one of our videos , you can get it at patreon.com/kurzgesagt .


Patreon is one of the main ways we sustain ourselves, so on top of getting a super nice avatar, you also help us make more and better videos.

Patreon is one of the main ways we sustain ourselves , so on top of getting a super nice avatar , you also help us make more and better videos .


Black holes are the most powerful and extreme things in the universe, and they're wildly weird and complicated.

Black holes are the most powerful and extreme things in the universe , and they 're wildly weird and complicated .


What would happen if you fell inside one, and what are they really?

What would happen if you fell inside one , and what are they really ?


First, we need to talk about space and time.

First , we need to talk about space and time .


Space and time are the grand stage where the play of the universe unfolds.

Space and time are the grand stage where the play of the universe unfolds .


But space isn't a fixed stage, and time doesn't tick the same for everyone everywhere.

But space is n't a fixed stage , and time does n't tick the same for everyone everywhere .


In short, they're relative.


Matter bends space, and bent space tells matter how to move.

Matter bends space , and bent space tells matter how to move .


Put some stars and planets on the stage, and it sacks underneath them.

Put some stars and planets on the stage , and it sacks underneath them .


That misshapen stage, with all its little warps and dips, gives us gravity.

That misshapen stage , with all its little warps and dips , gives us gravity .


Black holes do not just bend the stage, they're like trapdoors.

Black holes do not just bend the stage , they 're like trapdoors .


Most black holes form when very massive stars die.

Most black holes form when very massive stars die .


We explained this process in detail in our neutron star video.

We explained this process in detail in our neutron star video .


All you need to know now is that in the final moments of really massive stars, their insides implode at nearly a quarter of the speed of light.

All you need to know now is that in the final moments of really massive stars , their insides implode at nearly a quarter of the speed of light .


This packs so much mass so close together, creating something so dense that it sort of breaks the stage of the universe.

This packs so much mass so close together , creating something so dense that it sort of breaks the stage of the universe .


A black hole with ten times the mass of the sun would be barely 60 kilometers across.

A black hole with ten times the mass of the sun would be barely 60 kilometers across .


If you look directly at a black hole, it looks like nothing.

If you look directly at a black hole , it looks like nothing .


The space under their control is blocked by an invisible, one-way border called the event horizon.

The space under their control is blocked by an invisible , one - way border called the event horizon .


The event horizon forms a shell around a region of space that once entered is shielded from the rest of the universe forever.

The event horizon forms a shell around a region of space that once entered is shielded from the rest of the universe forever .


Because the black hole trapdoor deforms space so much, not even light can escape it.

Because the black hole trapdoor deforms space so much , not even light can escape it .


And with nothing escaping to transfer information from the inside, it's impossible to tell what it really looks like.

And with nothing escaping to transfer information from the inside , it 's impossible to tell what it really looks like .


We can still observe black holes because of their effect on matter.

We can still observe black holes because of their effect on matter .


Things can orbit black holes just as they can orbit the sun or a planet.

Things can orbit black holes just as they can orbit the sun or a planet .


Many black holes have disks of matter orbiting outside the event horizon.

Many black holes have disks of matter orbiting outside the event horizon .


This matter can become incredibly hot as close orbits can speed this matter up to half the speed of light,

This matter can become incredibly hot as close orbits can speed this matter up to half the speed of light ,


and tiny amounts of friction and collisions between particles heat them to a billion degrees, making the space around these black holes ironically incredibly bright.

and tiny amounts of friction and collisions between particles heat them to a billion degrees , making the space around these black holes ironically incredibly bright .


What would happen if you were to try to get close or even inside a black hole?

What would happen if you were to try to get close or even inside a black hole ?


First of all, you'd see the strangest funhouse mirror in the universe.

First of all , you 'd see the strangest funhouse mirror in the universe .


Matter isn't the only thing orbiting a black hole.

Matter is n't the only thing orbiting a black hole .


Gravity is so strong near them that light can orbit too.

Gravity is so strong near them that light can orbit too .


If you hover just outside the event horizon, at the photon sphere, in any direction, you just see yourself.

If you hover just outside the event horizon , at the photon sphere , in any direction , you just see yourself .


Straight ahead would be the back of your own head, as light from your back travels around the black hole to your eyes.

Straight ahead would be the back of your own head , as light from your back travels around the black hole to your eyes .


Gravity also alters the passage of time itself.

Gravity also alters the passage of time itself .


The stronger the gravity, the slower time passes.

The stronger the gravity , the slower time passes .


While you watch the universe above you speed up, those far away will watch you in slow motion.

While you watch the universe above you speed up , those far away will watch you in slow motion .


If you chose to fly away from the black hole, you might find that eons have passed for the rest of the universe,

If you chose to fly away from the black hole , you might find that eons have passed for the rest of the universe ,


But getting close to a black hole can be incredibly dangerous.

But getting close to a black hole can be incredibly dangerous .


A painful death by spaghettification awaits you.

A painful death by spaghettification awaits you .


Because your feet are closer to the black hole than your head, they feel a stronger pull of gravity, enough to pull you apart.

Because your feet are closer to the black hole than your head , they feel a stronger pull of gravity , enough to pull you apart .


As you descend, it gets worse.


The pulling gets stronger, your body squeezed thinner and straighter,

The pulling gets stronger , your body squeezed thinner and straighter ,


until you've been reduced to a thin stream of hot plasma, gobbled up in one final slurp, never to be seen again.

until you 've been reduced to a thin stream of hot plasma , gobbled up in one final slurp , never to be seen again .


Spaghettification is only a risk with smaller black holes, since they have much smaller radii.

Spaghettification is only a risk with smaller black holes , since they have much smaller radii .


If you go to the center of a galaxy and find a supermassive black hole, you might be able to experience crossing the event horizon.

If you go to the center of a galaxy and find a supermassive black hole , you might be able to experience crossing the event horizon .


As you approach the event horizon, a distant observer would think they never saw you enter it, seeing you stop and fade.

As you approach the event horizon , a distant observer would think they never saw you enter it , seeing you stop and fade .


Meanwhile, from your perspective, the void of the black hole rises up to meet you, as light from fewer directions can reach you.

Meanwhile , from your perspective , the void of the black hole rises up to meet you , as light from fewer directions can reach you .


The blackness envelops you until your only view of the universe you left is a tiny spot of light.

The blackness envelops you until your only view of the universe you left is a tiny spot of light .


Here, inside the event horizon, space and time are so horribly broken that real time travel is possible, so it's probably a good thing that nothing gets out.

Here , inside the event horizon , space and time are so horribly broken that real time travel is possible , so it 's probably a good thing that nothing gets out .


If anything could escape, it could create all sorts of time travel paradoxes and issues that break the universe.

If anything could escape , it could create all sorts of time travel paradoxes and issues that break the universe .


As scary as the event horizon is, it keeps us safe from that drama.

As scary as the event horizon is , it keeps us safe from that drama .


Whether you have survived this long doesn't really matter, as now there's only the certainty of crushing death in your near future.

Whether you have survived this long does n't really matter , as now there 's only the certainty of crushing death in your near future .


Inside the event horizon, space-time itself is so bent and warped that whatever direction you move here,

Inside the event horizon , space - time itself is so bent and warped that whatever direction you move here ,


every forward you go leads only towards the center of the black hole.

every forward you go leads only towards the center of the black hole .


Trying to go in any direction only brings you to the center faster.

Trying to go in any direction only brings you to the center faster .


To survive the longest, you must do nothing.

To survive the longest , you must do nothing .


In the center of the black hole, we find the singularity, a single point with all the matter that has ever crossed the event horizon,

In the center of the black hole , we find the singularity , a single point with all the matter that has ever crossed the event horizon ,


all crushed to a point infinitely small.

all crushed to a point infinitely small .


There is no memory of the things that made it, as stuff disappears down the black hole trapdoor forever.

There is no memory of the things that made it , as stuff disappears down the black hole trapdoor forever .


The singularity makes all things equal.

The singularity makes all things equal .


This actually breaks the universe in really cool ways.

This actually breaks the universe in really cool ways .


We've made a video about this problem if you want to learn more.

We 've made a video about this problem if you want to learn more .


But in a nutshell, everything that comes too close becomes black hole matter concentrated at the singularity.

But in a nutshell , everything that comes too close becomes black hole matter concentrated at the singularity .


This lack of a memory of its past means that a black hole has only three properties.

This lack of a memory of its past means that a black hole has only three properties .


Everything else is lost.


They're a lot like fundamental particles in that respect.

They 're a lot like fundamental particles in that respect .


This actually means that every single black hole in the universe is the same.

This actually means that every single black hole in the universe is the same .


Sure, their mass is different, and some spin faster than others,

Sure , their mass is different , and some spin faster than others ,


but if we were to put all the singularities into a magical physics museum, they'd be identical, like electrons.

but if we were to put all the singularities into a magical physics museum , they 'd be identical , like electrons .


But just like fundamental particles, the properties of singularities are the best ways we can describe them on paper,

But just like fundamental particles , the properties of singularities are the best ways we can describe them on paper ,


Our current theories about the universe, namely general relativity, are just not able to describe or explain them.

Our current theories about the universe , namely general relativity , are just not able to describe or explain them .


The curvature of space becomes infinite, density becomes infinite, and our rules just don't make sense.

The curvature of space becomes infinite , density becomes infinite , and our rules just do n't make sense .


The singularity has no surface or size, something like a divide by zero error in the universe.

The singularity has no surface or size , something like a divide by zero error in the universe .


So singularities might not even exist, or be completely different things.

So singularities might not even exist , or be completely different things .


But this is all we know right now, from the best prediction we have, from our best current theory of space-time.

But this is all we know right now , from the best prediction we have , from our best current theory of space - time .


as far as we know, all black holes in the universe should be spinning right now.

as far as we know , all black holes in the universe should be spinning right now .


This means that in reality, black holes are even more screwed up than they usually get credit for.

This means that in reality , black holes are even more screwed up than they usually get credit for .


The singularities of rotating black holes are even wilder.

The singularities of rotating black holes are even wilder .


The rotation causes them to swell outwards into a sort of ringularity.

The rotation causes them to swell outwards into a sort of ringularity .


This rotation is so powerful that space itself is dragged along.

This rotation is so powerful that space itself is dragged along .


This creates another region around spinning black holes called the ergosphere, where it's impossible to stay still no matter how hard you try.

This creates another region around spinning black holes called the ergosphere , where it 's impossible to stay still no matter how hard you try .


Like a rushing whirlpool of space-time, the tide is irresistible, and the black hole makes you orbit it whether you want to or not.

Like a rushing whirlpool of space - time , the tide is irresistible , and the black hole makes you orbit it whether you want to or not .


Okay, so what will happen to black holes as the universe ages and dies around them?

Okay , so what will happen to black holes as the universe ages and dies around them ?


Again, we don't know, but we have some ideas based on our current understanding of physics.

Again , we do n't know , but we have some ideas based on our current understanding of physics .


In quantum field theory, the vacuum of space is boiling with quantum fluctuations.

In quantum field theory , the vacuum of space is boiling with quantum fluctuations .


These fluctuations are creating matter and antimatter pairs of particles from nothing, which only exist for a very short time before annihilating.

These fluctuations are creating matter and antimatter pairs of particles from nothing , which only exist for a very short time before annihilating .


When this happens near the event horizon of a black hole, one of these particles can fall in, stopping them from annihilating.

When this happens near the event horizon of a black hole , one of these particles can fall in , stopping them from annihilating .


The escaping particle is Hawking radiation.

The escaping particle is Hawking radiation .


Ultimately, the mass of this particle must come from the black hole, so over eons, black holes will shrink and radiate away.

Ultimately , the mass of this particle must come from the black hole , so over eons , black holes will shrink and radiate away .


Hawking radiation is not the stuff that fell into the black hole, it's new stuff stealing mass from it.

Hawking radiation is not the stuff that fell into the black hole , it 's new stuff stealing mass from it .


As the black hole shrinks, the Hawking radiation gets stronger, faster and faster,

As the black hole shrinks , the Hawking radiation gets stronger , faster and faster ,


until what's left eventually evaporates in a flash of high-energy radiation like a nuclear bomb.

until what 's left eventually evaporates in a flash of high - energy radiation like a nuclear bomb .


But that won't happen for a long, long time.

But that wo n't happen for a long , long time .


A black hole with the mass of our sun has a lifetime of 10 to the power of 67 years,

A black hole with the mass of our sun has a lifetime of 10 to the power of 67 years ,


But most black holes are way more massive than our sun.

But most black holes are way more massive than our sun .


The most massive supermassive black holes in the centers of galaxies have lifetimes of 10 to the power of 100 years.

The most massive supermassive black holes in the centers of galaxies have lifetimes of 10 to the power of 100 years .


How long is that?


Imagine an hourglass, filled with one grain of sand for every single particle in the universe.

Imagine an hourglass , filled with one grain of sand for every single particle in the universe .


Every 10 billion years, one single grain of sand falls to the bottom.

Every 10 billion years , one single grain of sand falls to the bottom .


If we waited for all the sand to fall down, not even 1% of the lifetimes of these black holes would have passed.

If we waited for all the sand to fall down , not even 1 % of the lifetimes of these black holes would have passed .


There is no good concept to help our brains grasp these timescales.

There is no good concept to help our brains grasp these timescales .


Will we ever truly understand black holes?

Will we ever truly understand black holes ?


No one knows.


We can only see their outsides, and the theories we have probably get their insides wrong.

We can only see their outsides , and the theories we have probably get their insides wrong .


But it's okay to not know everything.


It just means there's still work to be done.

It just means there 's still work to be done .


It means there are still mysteries to solve, and big ideas to think about, which is why humans do science.

It means there are still mysteries to solve , and big ideas to think about , which is why humans do science .


In the end, we can at least be sure that we still have plenty of time left to think about them, before the last one melts away.

In the end , we can at least be sure that we still have plenty of time left to think about them , before the last one melts away .


If you want to continue thinking about black holes, you can do so by getting one of the many black hole-related things the Kurzgesagt team has made with love.

If you want to continue thinking about black holes , you can do so by getting one of the many black hole - related things the Kurzgesagt team has made with love .


In which case, we've made a black hole and white hole plushie.

In which case , we 've made a black hole and white hole plushie .


And if that's still not enough, we've also just released super comfy space socks, very shiny space pins, a new tote bag and pouch set,

And if that 's still not enough , we 've also just released super comfy space socks , very shiny space pins , a new tote bag and pouch set ,


and we have many other great space-related products, that are all designed with love and care by us here at Kurzgesagt.

and we have many other great space - related products , that are all designed with love and care by us here at Kurzgesagt .


Getting something from our shop is the best way of supporting Kurzgesagt, while getting something beautiful in return.

Getting something from our shop is the best way of supporting Kurzgesagt , while getting something beautiful in return .


Because of you, we can keep making elaborate videos like the one you just watched, and release them for free for everyone.

Because of you , we can keep making elaborate videos like the one you just watched , and release them for free for everyone .


Thank you so much for your support.


Humans are proud of a lot of things, from particle accelerators, to poetry, to Pokemon.

Humans are proud of a lot of things , from particle accelerators , to poetry , to Pokemon .


We think of intelligence as a trait, like height or strength, but when we try to define it, things get fuzzy.

We think of intelligence as a trait , like height or strength , but when we try to define it , things get fuzzy .


In a nutshell, intelligence is a mechanism to solve problems, especially the problem of staying alive,

In a nutshell , intelligence is a mechanism to solve problems , especially the problem of staying alive ,


Intelligence is not a single thing.


It includes the ability to gather knowledge, to learn, be creative, form strategies, or engage in critical thinking.

It includes the ability to gather knowledge , to learn , be creative , form strategies , or engage in critical thinking .


It manifests itself in a huge variety of behaviors, from hard-wired or instinct-like reactions to different degrees of learning to some sort of awareness.

It manifests itself in a huge variety of behaviors , from hard - wired or instinct - like reactions to different degrees of learning to some sort of awareness .


But not all scientists agree where it begins or what even should count as intelligence.

But not all scientists agree where it begins or what even should count as intelligence .


To make this even more complicated, intelligence is also connected to consciousness, since awareness is helpful for problem-solving.

To make this even more complicated , intelligence is also connected to consciousness , since awareness is helpful for problem - solving .


But we're exploring consciousness in other videos, so today we'll leave it aside.

But we 're exploring consciousness in other videos , so today we 'll leave it aside .


Okay, intelligence isn't exactly clear-cut, so maybe we can think of it as more like a flexible set of skills.

Okay , intelligence is n't exactly clear - cut , so maybe we can think of it as more like a flexible set of skills .


The most basic tools in the intelligence toolbox are the ability to gather information, to save it, and to use it to learn.

The most basic tools in the intelligence toolbox are the ability to gather information , to save it , and to use it to learn .


Information about the world is gathered through senses such as vision, sound, smell, touch, or taste, and helps us navigate and react to the external world appropriately.

Information about the world is gathered through senses such as vision , sound , smell , touch , or taste , and helps us navigate and react to the external world appropriately .


But living things also need to keep track of the state of their own bodies, monitoring things like hunger and fatigue.

But living things also need to keep track of the state of their own bodies , monitoring things like hunger and fatigue .


Information is the basis of action for all living things, and without it, you're at the mercy of your surroundings, unable to react appropriately or flexibly.

Information is the basis of action for all living things , and without it , you 're at the mercy of your surroundings , unable to react appropriately or flexibly .


Information is much more powerful if we can keep and save it.

Information is much more powerful if we can keep and save it .


So the second tool is memory.


Memory is the ability to save and recall information so a living being doesn't have to start from scratch every time it perceives something relevant.

Memory is the ability to save and recall information so a living being does n't have to start from scratch every time it perceives something relevant .


Memories can be about events, places, and associations, but also behaviors like hunting or foraging methods.

Memories can be about events , places , and associations , but also behaviors like hunting or foraging methods .


Some of these, like flying, have to be repeated over and over until they're mastered.

Some of these , like flying , have to be repeated over and over until they 're mastered .


This is what we call learning, the process of putting together a sequence of thoughts or actions.

This is what we call learning , the process of putting together a sequence of thoughts or actions .


These three tools enable seemingly stupid creatures to act in surprisingly intelligent ways.

These three tools enable seemingly stupid creatures to act in surprisingly intelligent ways .


The acellular slime mold, which is basically just a single huge slimy cell, shows behavior similar to an animal with a simple brain.

The acellular slime mold , which is basically just a single huge slimy cell , shows behavior similar to an animal with a simple brain .


When put in a maze with food at one end, the slime mold explores its surroundings and marks its path with slime trails, sort of smearing memories on the ground.

When put in a maze with food at one end , the slime mold explores its surroundings and marks its path with slime trails , sort of smearing memories on the ground .


As it continues exploring, it avoids the marked pathways and finds its way to the food.

As it continues exploring , it avoids the marked pathways and finds its way to the food .


Instead of blindly getting stuck in dead ends, the slime mold adapts its behavior to save time and effort.

Instead of blindly getting stuck in dead ends , the slime mold adapts its behavior to save time and effort .


This behavior is hardwired, and scientists can't agree if that's intelligent, although it does give the slime mold a certain advantage.

This behavior is hardwired , and scientists ca n't agree if that 's intelligent , although it does give the slime mold a certain advantage .


Bees are an example of more adaptive smart behavior.

Bees are an example of more adaptive smart behavior .


Scientists trained bumblebees to move a colored ball into a goalpost for a sugar reward.

Scientists trained bumblebees to move a colored ball into a goalpost for a sugar reward .


Not only were the bees very skillful at this behavior, which isn't natural to them, they got more efficient over time.

Not only were the bees very skillful at this behavior , which is n't natural to them , they got more efficient over time .


When several balls were available, bees chose the ball that lay closest to the goal, even if it was a different color than the ball they were trained with.

When several balls were available , bees chose the ball that lay closest to the goal , even if it was a different color than the ball they were trained with .


For more challenging problems, we need even more flexibility.

For more challenging problems , we need even more flexibility .


Building on the basic tools, more complex animals have a wider range of problems they can solve.

Building on the basic tools , more complex animals have a wider range of problems they can solve .


They can memorize all kinds of associations, connections, and mechanical tricks.

They can memorize all kinds of associations , connections , and mechanical tricks .


We'll call this tool the library of knowledge.

We 'll call this tool the library of knowledge .


Take raccoons.


Their favorite kind of food is human food.

Their favorite kind of food is human food .


Their approach to getting hold of such treats depends upon an assortment of theoretical and practical skills that makes them master burglars, able to open windows or pick locks.

Their approach to getting hold of such treats depends upon an assortment of theoretical and practical skills that makes them master burglars , able to open windows or pick locks .


In a study, raccoons were given boxes secured with different kinds of locks, like latches, bolts, plugs, or push bars.

In a study , raccoons were given boxes secured with different kinds of locks , like latches , bolts , plugs , or push bars .


They needed less than 10 attempts to figure out how to open each box,

They needed less than 10 attempts to figure out how to open each box ,


A year later, the raccoons still remembered how to open the boxes and were as fast as when they had first solved the puzzle.

A year later , the raccoons still remembered how to open the boxes and were as fast as when they had first solved the puzzle .


Beyond our library of associations and skills, the most impressive tool in our box is creativity, a sort of mental duct tape.

Beyond our library of associations and skills , the most impressive tool in our box is creativity , a sort of mental duct tape .


Being creative means producing something new and valuable from apparently unrelated things.

Being creative means producing something new and valuable from apparently unrelated things .


In the context of intelligence, this means making new and unusual connections, pairing input with memories and skills to come up with a unique solution to a problem.

In the context of intelligence , this means making new and unusual connections , pairing input with memories and skills to come up with a unique solution to a problem .


In another raccoon study, researchers showed the animals that by dropping pebbles into a water tank,

In another raccoon study , researchers showed the animals that by dropping pebbles into a water tank ,


they could raise the water level enough to reach a marshmallow floating at the top.

they could raise the water level enough to reach a marshmallow floating at the top .


One raccoon came up with a much better solution.

One raccoon came up with a much better solution .


It tipped the tub over.


Another facet of creativity is applying a new resource to a task, physical tools.

Another facet of creativity is applying a new resource to a task , physical tools .


or some octopuses which assemble collected coconut shells around themselves as a sort of portable armor to hide from enemies.

or some octopuses which assemble collected coconut shells around themselves as a sort of portable armor to hide from enemies .


Collecting materials for later use is connected to an even more advanced dimension of problem solving, planning.

Collecting materials for later use is connected to an even more advanced dimension of problem solving , planning .


Planning means considering the activities required for a desired goal and putting them together in a plan.

Planning means considering the activities required for a desired goal and putting them together in a plan .


When unforeseen circumstances and new possibilities present themselves, they need to be assessed according to whether they match the plan or not.

When unforeseen circumstances and new possibilities present themselves , they need to be assessed according to whether they match the plan or not .


An example of this intelligent behavior is hoarding food to eat it later.

An example of this intelligent behavior is hoarding food to eat it later .


This is an instinctive behavior in squirrels.

This is an instinctive behavior in squirrels .


But even though hiding food comes instinctively to them, they still need to use advanced thinking skills to make the best decisions.

But even though hiding food comes instinctively to them , they still need to use advanced thinking skills to make the best decisions .


Squirrels examine every nut and weigh the time and effort it would take to hide it against the benefits they would get from each one.

Squirrels examine every nut and weigh the time and effort it would take to hide it against the benefits they would get from each one .


Damaged or low-fat nuts are eaten right away, while nuts that still need to ripen go on the stockpile.

Damaged or low - fat nuts are eaten right away , while nuts that still need to ripen go on the stockpile .


Squirrels also pretend to bury nuts when they feel watched.

Squirrels also pretend to bury nuts when they feel watched .


These empty caches distract rivals from their real treasure.

These empty caches distract rivals from their real treasure .


This is pretty advanced strategizing because to make a plan to distract someone else, you first have to be aware that there are others like you that want the same things.

This is pretty advanced strategizing because to make a plan to distract someone else , you first have to be aware that there are others like you that want the same things .


The more complex the problem, the more tools are needed in combination to solve it.

The more complex the problem , the more tools are needed in combination to solve it .


So the more tools there are, the more flexibility a being has to solve the challenges life throws at them.

So the more tools there are , the more flexibility a being has to solve the challenges life throws at them .


But even for complex problems, each animal's individual situation is what counts.

But even for complex problems , each animal 's individual situation is what counts .


Squirrels are omnivores that defend their territories fiercely.

Squirrels are omnivores that defend their territories fiercely .


For them, it makes sense to remember where there's food in different locations and trick their enemies to improve their chances of survival.

For them , it makes sense to remember where there 's food in different locations and trick their enemies to improve their chances of survival .


Sheep don't have any such refined tricks up their sleeve, but they don't need to.

Sheep do n't have any such refined tricks up their sleeve , but they do n't need to .


They are grazers and live in flocks.


The skills relevant to them are social.

The skills relevant to them are social .


They recognize and remember many different sheep and even humans for years.

They recognize and remember many different sheep and even humans for years .


Evolving and retaining a complex set of mental abilities they might never use would be a waste of resources for them.

Evolving and retaining a complex set of mental abilities they might never use would be a waste of resources for them .


Humans went the opposite way and invested in an unusually diverse intelligence toolkit.

Humans went the opposite way and invested in an unusually diverse intelligence toolkit .


While this was helpful, by accident we added another set of tools on top.

While this was helpful , by accident we added another set of tools on top .


No single person could ever build a space rocket or particle accelerator.

No single person could ever build a space rocket or particle accelerator .


But thanks to our ability to work together and to share knowledge across generations, we can overcome challenges beyond any single individual's ability.

But thanks to our ability to work together and to share knowledge across generations , we can overcome challenges beyond any single individual 's ability .


This allowed us to shape the planet to our liking.

This allowed us to shape the planet to our liking .


We also created new problems in the process.

We also created new problems in the process .


To solve these, we'll need to look past short-term survival and think about the distant future.

To solve these , we 'll need to look past short - term survival and think about the distant future .


We have the toolbox.


We just need to use it.


Speaking of tools for learning, we've heard from many teachers that are using our infographic posters in class.

Speaking of tools for learning , we 've heard from many teachers that are using our infographic posters in class .


So we asked what would help them the most and made an education edition.

So we asked what would help them the most and made an education edition .


They're slightly larger posters about various things that will expand over time.

They 're slightly larger posters about various things that will expand over time .


You can get them in our shop and support us if you want.

You can get them in our shop and support us if you want .


And let us know which poster topics you want for your room or classroom.

And let us know which poster topics you want for your room or classroom .


This video was part two of a three-part video series relating to big questions of life and the universe.

This video was part two of a three - part video series relating to big questions of life and the universe .


You'll find our sources and further reading in the video description.

You 'll find our sources and further reading in the video description .


Life is fundamentally different from dead stuff, or is it?

Life is fundamentally different from dead stuff , or is it ?


Physicist Erwin Schrodinger defined life this way.

Physicist Erwin Schrodinger defined life this way .


Living things avoid decay into disorder and equilibrium.

Living things avoid decay into disorder and equilibrium .


What does this mean?


Let's pretend that your download folder is the universe.

Let 's pretend that your download folder is the universe .


It started orderly and got more and more chaotic over time.

It started orderly and got more and more chaotic over time .


By investing energy, you can create order and clean it up.

By investing energy , you can create order and clean it up .


This is what living things do.


But what is life?


Every living thing on this planet is made of cells.

Every living thing on this planet is made of cells .


Basically, a cell is a protein-based robot too small to feel or experience anything.

Basically , a cell is a protein - based robot too small to feel or experience anything .


It has the properties we just assigned to life.

It has the properties we just assigned to life .


It has a wall that separates it from the surroundings creating order.

It has a wall that separates it from the surroundings creating order .


It regulates itself and maintains a constant state.

It regulates itself and maintains a constant state .


It eats stuff to stay alive.


It grows and develops.


It reacts to the environment and it's subject to evolution.

It reacts to the environment and it 's subject to evolution .


And it makes more of itself.


But of all the stuff that makes up a cell, no part is alive.

But of all the stuff that makes up a cell , no part is alive .


Stuff reacts chemically with other stuff, forming reactions that start other reactions, which start other reactions.

Stuff reacts chemically with other stuff , forming reactions that start other reactions , which start other reactions .


In a single cell every second, several million chemical reactions take place, forming a complex orchestra.

In a single cell every second , several million chemical reactions take place , forming a complex orchestra .


A cell can build several thousand types of protein.

A cell can build several thousand types of protein .


Imagine driving a car at 100 kilometers an hour while constantly rebuilding every single part of it with stuff you collect from the street.

Imagine driving a car at 100 kilometers an hour while constantly rebuilding every single part of it with stuff you collect from the street .


That is what cells do.


But no part of the cell is alive.


Everything is dead matter moved by the laws of the universe.

Everything is dead matter moved by the laws of the universe .


So is life the aggregate of all these reaction processes that are taking place?

So is life the aggregate of all these reaction processes that are taking place ?


Eventually every living thing will die.

Eventually every living thing will die .


The goal of the whole process is to prevent this by producing new entities.

The goal of the whole process is to prevent this by producing new entities .


And by this we mean DNA.


Life is in a way just a lot of stuff that carries genetic information around.

Life is in a way just a lot of stuff that carries genetic information around .


Every living thing is subject to evolution and the DNA that develops the best living thing around it will stay in the game.

Every living thing is subject to evolution and the DNA that develops the best living thing around it will stay in the game .


If you take DNA out of its hull, it certainly is a very complex molecule, but it can't do anything by itself.

If you take DNA out of its hull , it certainly is a very complex molecule , but it ca n't do anything by itself .


This is where viruses make everything more complicated.

This is where viruses make everything more complicated .


They are basically strings of RNA or DNA in a small hull and need cells to do something.

They are basically strings of RNA or DNA in a small hull and need cells to do something .


We're not sure if they count as living or dead.

We 're not sure if they count as living or dead .


And still there are 225 million cubic meters of viruses on Earth.

And still there are 225 million cubic meters of viruses on Earth .


They don't seem to care what we think of them.

They do n't seem to care what we think of them .


There are even viruses that invade dead cells and reanimate them so they can be a host for them, which blurs the line even more.

There are even viruses that invade dead cells and reanimate them so they can be a host for them , which blurs the line even more .


They are the power plants of most complex cells and were previously free living bacteria that entered a partnership with bigger cells.

They are the power plants of most complex cells and were previously free living bacteria that entered a partnership with bigger cells .


They still have their own DNA and can multiply on their own, but they are not alive anymore.

They still have their own DNA and can multiply on their own , but they are not alive anymore .


They are dead.


So maybe life is information that manages to ensure its continued existence.

So maybe life is information that manages to ensure its continued existence .


By our most common definitions, we are very close to creating artificial life in computers.

By our most common definitions , we are very close to creating artificial life in computers .


It's just a question of time before the technology we build gets there.

It 's just a question of time before the technology we build gets there .


And this is not science fiction either.

And this is not science fiction either .


There are a lot of smart people actively working on this.

There are a lot of smart people actively working on this .


You could already argue that computer viruses are alive.

You could already argue that computer viruses are alive .


So what is life then?


This got confusing very fast.


One thing is for sure, the idea that life is fundamentally different from non-living things

One thing is for sure , the idea that life is fundamentally different from non - living things


Before Charles Darwin, humans drew a line between themselves and the rest of living things.

Before Charles Darwin , humans drew a line between themselves and the rest of living things .


There was something magical about us that made us special.

There was something magical about us that made us special .


Once we had to accept we are, like every living being, a product of evolution, we drew a different line.

Once we had to accept we are , like every living being , a product of evolution , we drew a different line .


But the more we learn about what computers can do and how life works, the closer we get to creating the first machine that fits our description of life,

But the more we learn about what computers can do and how life works , the closer we get to creating the first machine that fits our description of life ,


the more our image of ourselves is in danger again.

the more our image of ourselves is in danger again .


And this will happen sooner or later.


And here's another question for you.


Does this mean we can never die because we were never alive in the first place?

Does this mean we can never die because we were never alive in the first place ?


Is life and death an irrelevant question and we haven't noticed it yet?

Is life and death an irrelevant question and we have n't noticed it yet ?


Is it possible we are much more part of the universe around us than we thought?

Is it possible we are much more part of the universe around us than we thought ?


Don't look at us.


We don't have any answers for you, just questions for you to think about.

We do n't have any answers for you , just questions for you to think about .


The international banking system is an enigma.

The international banking system is an enigma .


There are more than 30,000 different banks worldwide,

There are more than 30,000 different banks worldwide ,


and they hold unbelievable amounts of assets.

and they hold unbelievable amounts of assets .


The top 10 banks alone account for roughly 25 trillion US dollars.

The top 10 banks alone account for roughly 25 trillion US dollars .


Today, banking can seem very complex,


but originally, the idea was to make life simpler.

but originally , the idea was to make life simpler .


11th century Italy was the center of European trading.

11th century Italy was the center of European trading .


Merchants from all over the continent met to trade their goods,

Merchants from all over the continent met to trade their goods ,


but there was one problem.


In Pisa, merchants had to deal with seven different types of coins

In Pisa , merchants had to deal with seven different types of coins


and the difficulty of getting a loan got people thinking.

and the difficulty of getting a loan got people thinking .


It was time for a new business model.


Hornbrokers started to give credit to businessmen,

Hornbrokers started to give credit to businessmen ,


Networks of banks spread all over Europe,

Networks of banks spread all over Europe ,


This is a simplified version of the way it works.

This is a simplified version of the way it works .


People keep their money in banks and receive a small amount of interest.

People keep their money in banks and receive a small amount of interest .


The bank takes this money and lends it out at much higher interest rates.

The bank takes this money and lends it out at much higher interest rates .


It's a calculated risk, because some of the lenders will default on their credit.

It 's a calculated risk , because some of the lenders will default on their credit .


This process is essential for our economic system,

This process is essential for our economic system ,


So banks take funds that are unused by savers


Other sources of income for banks include accepting saving deposits,

Other sources of income for banks include accepting saving deposits ,


The main problem with banks nowadays is that a lot of them have abandoned their traditional role as providers of long-term financial products

The main problem with banks nowadays is that a lot of them have abandoned their traditional role as providers of long - term financial products


During the financial boom, most major banks adopted financial constructs that were barely comprehensible

During the financial boom , most major banks adopted financial constructs that were barely comprehensible


This was nothing short of gambling and damaged whole economies and societies.

This was nothing short of gambling and damaged whole economies and societies .


This led to the collapse of the housing market in the US and parts of Europe,

This led to the collapse of the housing market in the US and parts of Europe ,


Hundreds of billions of dollars just evaporated.

Hundreds of billions of dollars just evaporated .


Millions of people lost their jobs and lots of money.

Millions of people lost their jobs and lots of money .


Most of the world's major banks had to pay billions in fines and bankers became some of the least trusted professionals.

Most of the world 's major banks had to pay billions in fines and bankers became some of the least trusted professionals .


The US government and the European Union had to put together huge bailout packages to purchase bad assets and stop the banks from going bankrupt.

The US government and the European Union had to put together huge bailout packages to purchase bad assets and stop the banks from going bankrupt .


New regulations were put into force to govern the banking business.

New regulations were put into force to govern the banking business .


Compulsory bank emergency funds were enforced to absorb shocks in the event of another financial crisis.

Compulsory bank emergency funds were enforced to absorb shocks in the event of another financial crisis .


But other pieces of tough new legislation were successfully blocked by the banking lobby.

But other pieces of tough new legislation were successfully blocked by the banking lobby .


Today, other models of providing financing are gaining ground fast.

Today , other models of providing financing are gaining ground fast .


In a nutshell, they provide the same financial services as banks,

In a nutshell , they provide the same financial services as banks ,


The self-proclaimed goal is to help members create opportunities like starting small businesses,

The self - proclaimed goal is to help members create opportunities like starting small businesses ,


They are controlled by their members, who also elect the board of directors democratically.

They are controlled by their members , who also elect the board of directors democratically .


Worldwide, credit union systems vary significantly,

Worldwide , credit union systems vary significantly ,


Aside from making awesome video games possible, platforms arose that enable people to get loans from large groups of small investors, circumventing the bank as a middleman.

Aside from making awesome video games possible , platforms arose that enable people to get loans from large groups of small investors , circumventing the bank as a middleman .


But it also works for industry.


Lots of new technology companies started out on Kickstarter or Indiegogo.

Lots of new technology companies started out on Kickstarter or Indiegogo .


The funding individual gets the satisfaction of being part of a bigger thing and can invest in ideas they believe in,

The funding individual gets the satisfaction of being part of a bigger thing and can invest in ideas they believe in ,


Nowadays, the granting of microcredits has evolved into a multi-billion dollar business.

Nowadays , the granting of microcredits has evolved into a multi - billion dollar business .


So, banking might not be up your street, but the bank's role of providing funds to people and businesses is crucial for our society and has to be done.

So , banking might not be up your street , but the bank 's role of providing funds to people and businesses is crucial for our society and has to be done .


Who will do it and how it will be done in the future is up for us to decide though.

Who will do it and how it will be done in the future is up for us to decide though .


Light is the connection between us and the universe.

Light is the connection between us and the universe .


Through light, we can experience distant stars and look back at the beginning of existence itself.

Through light , we can experience distant stars and look back at the beginning of existence itself .


But what is light?


In a nutshell, light is the smallest quantity of energy that can be transported.

In a nutshell , light is the smallest quantity of energy that can be transported .


A photon, an elementary particle without a real size that can't be split, only created or destroyed.

A photon , an elementary particle without a real size that ca n't be split , only created or destroyed .


Light also has a wave-particle duality, being kind of a particle and a wave at the same time, although this is a lie.

Light also has a wave - particle duality , being kind of a particle and a wave at the same time , although this is a lie .


Also, when we say light, we actually mean visible light, which is a tiny part of the electromagnetic spectrum, energy in form of electromagnetic radiation.

Also , when we say light , we actually mean visible light , which is a tiny part of the electromagnetic spectrum , energy in form of electromagnetic radiation .


Electromagnetic radiation consists of an enormous range of wavelengths and frequencies.

Electromagnetic radiation consists of an enormous range of wavelengths and frequencies .


Gamma rays have the smallest wavelengths because they're the highest energy photons.

Gamma rays have the smallest wavelengths because they 're the highest energy photons .


But most gamma rays are just under 10 picometers, which is still way smaller than a hydrogen atom.

But most gamma rays are just under 10 picometers , which is still way smaller than a hydrogen atom .


For reference, a hydrogen atom compared to a cent is about as big as a cent compared to the moon.

For reference , a hydrogen atom compared to a cent is about as big as a cent compared to the moon .


Visible light is in the middle of the spectrum, in the range of about 400 nanometers to 700 nanometers, about the size of bacteria.

Visible light is in the middle of the spectrum , in the range of about 400 nanometers to 700 nanometers , about the size of bacteria .


On the other end of the spectrum, radio waves can be up to 100 kilometers in diameter,

On the other end of the spectrum , radio waves can be up to 100 kilometers in diameter ,


From a physics standpoint, all these different waves are the same.

From a physics standpoint , all these different waves are the same .


They all have the wave-particle duality and travel at C, the speed of light, just at different frequencies.

They all have the wave - particle duality and travel at C , the speed of light , just at different frequencies .


So what makes visible light special then?

So what makes visible light special then ?


We just happen to have evolved eyes that are good at registering exactly this part of the electromagnetic spectrum.

We just happen to have evolved eyes that are good at registering exactly this part of the electromagnetic spectrum .


This is not a complete coincidence, though.

This is not a complete coincidence , though .


Visible light is the only set of electromagnetic radiation that propagates well in water, which happens to be where most eyes first evolved millions of years ago.

Visible light is the only set of electromagnetic radiation that propagates well in water , which happens to be where most eyes first evolved millions of years ago .


That was a smart move because light not only interacts with matter,

That was a smart move because light not only interacts with matter ,


it's also altered by it and can be used to gather information about the world around us with almost no delay, which is arguably really helpful for survival.

it 's also altered by it and can be used to gather information about the world around us with almost no delay , which is arguably really helpful for survival .


Okay, where does light come from?


A vast range of electromagnetic waves are created when atoms or molecules drop from a higher state of energy to a lower one.

A vast range of electromagnetic waves are created when atoms or molecules drop from a higher state of energy to a lower one .


They lose energy and emit it in the form of radiation.

They lose energy and emit it in the form of radiation .


At the microscopic level, visible light is created when an electron within an atom, that is, in an excited state, drops to a lower energy state and loses this excess energy.

At the microscopic level , visible light is created when an electron within an atom , that is , in an excited state , drops to a lower energy state and loses this excess energy .


The same way incoming light can elevate an electron to a higher state of energy by being absorbed by it.

The same way incoming light can elevate an electron to a higher state of energy by being absorbed by it .


Macroscopically, the moving charge of the electron creates an oscillating magnet field, which creates an oscillating electric field perpendicular to it.

Macroscopically , the moving charge of the electron creates an oscillating magnet field , which creates an oscillating electric field perpendicular to it .


These two fields move themselves through space, transferring energy from one place to another, carrying information about its place of creation with it.

These two fields move themselves through space , transferring energy from one place to another , carrying information about its place of creation with it .


Why, of all the things in the universe, is light the fastest thing there is?

Why , of all the things in the universe , is light the fastest thing there is ?


Let's change the question.


What is the fastest way to travel through space in the universe?

What is the fastest way to travel through space in the universe ?


It's C.


Electromagnetic radiation just happens to move this fast.

Electromagnetic radiation just happens to move this fast .


Any particle that has no mass travels at C, without acceleration or any in between.

Any particle that has no mass travels at C , without acceleration or any in between .


The light that's being released from a candle does not speed up until it reaches light speed.

The light that 's being released from a candle does not speed up until it reaches light speed .


At the very instant of its creation, its speed is C.

At the very instant of its creation , its speed is C.


So why is C, or the speed of light, finite then?

So why is C , or the speed of light , finite then ?


Well, nobody knows.


Our universe is just built this way.


We don't have a smart answer here.


So light is a part of a spectrum, an elementary particle that also behaves like a wave, propelled by two perpendicular fields, traveling at the speed limit of the universe.

So light is a part of a spectrum , an elementary particle that also behaves like a wave , propelled by two perpendicular fields , traveling at the speed limit of the universe .


Okay, that's nice and all, but what about all the crazy stuff about traveling at the speed of light and time, the twin paradox, quantum stuff, and things like that?

Okay , that 's nice and all , but what about all the crazy stuff about traveling at the speed of light and time , the twin paradox , quantum stuff , and things like that ?


We have to save them for another video.

We have to save them for another video .


For now, let's just be happy that we evolved eyes that pick up waves of information permeating the universe, making us see things that help us to put our existence into perspective.

For now , let 's just be happy that we evolved eyes that pick up waves of information permeating the universe , making us see things that help us to put our existence into perspective .


The simple questions are the hardest ones to answer.

The simple questions are the hardest ones to answer .


What is a thing?


Why do things happen?


And why do they happen the way they do?

And why do they happen the way they do ?


Let's try to approach this step by step.

Let 's try to approach this step by step .


What are you made of?


You are matter, which is made of molecules, which are made of atoms, and those are made of elementary particles.

You are matter , which is made of molecules , which are made of atoms , and those are made of elementary particles .


But, if elementary particles are the smallest things that exist, what are they made of?

But , if elementary particles are the smallest things that exist , what are they made of ?


To answer a simple question, let's start simply.

To answer a simple question , let 's start simply .


Let's wipe the universe clean, away with matter, antimatter, radiation, particles, anything.

Let 's wipe the universe clean , away with matter , antimatter , radiation , particles , anything .


Now let's take a closer look at absolutely nothing.

Now let 's take a closer look at absolutely nothing .


What is empty space?


Is it what we call a vacuum?


There are no atoms, no matter, nothing.

There are no atoms , no matter , nothing .


Is it really all that empty?


Nothing gives us the building blocks for everything.

Nothing gives us the building blocks for everything .


In a sense, empty space is a lot like a vast calm ocean.

In a sense , empty space is a lot like a vast calm ocean .


While the water is very still when nothing is happening, a stiff breeze can create some serious waves.

While the water is very still when nothing is happening , a stiff breeze can create some serious waves .


Our universe works a lot like this.


There are these oceans everywhere.


Physicists call them fields.


This might be strange and new, but think about radiation, for example.

This might be strange and new , but think about radiation , for example .


By exciting what's known as the electromagnetic field, a little kink is created, which is the particle we call the photon, the particle that carries radiation.

By exciting what 's known as the electromagnetic field , a little kink is created , which is the particle we call the photon , the particle that carries radiation .


We perceive it as light.


This isn't unique to light.


Every particle in the universe is made this way.

Every particle in the universe is made this way .


There are fields for every particle of matter, all with their own rules.

There are fields for every particle of matter , all with their own rules .


For example, along with the electromagnetic field, there is an electron field everywhere in the universe, and little kinks in that field are electrons.

For example , along with the electromagnetic field , there is an electron field everywhere in the universe , and little kinks in that field are electrons .


Altogether, the fields of our universe can produce 17 particles, which can be divided into three categories.

Altogether , the fields of our universe can produce 17 particles , which can be divided into three categories .


Leptons consist of the electron as well as its cousins, muon and tau particles.

Leptons consist of the electron as well as its cousins , muon and tau particles .


Each has an associated neutrino.


Then there are quarks.


The quarks are the nuclear family of particles.

The quarks are the nuclear family of particles .


They're always found bound together in groups and pairs and make up protons and neutrons, which make up the nuclei of atoms.

They 're always found bound together in groups and pairs and make up protons and neutrons , which make up the nuclei of atoms .


Together, the leptons and quarks are the matter particles.

Together , the leptons and quarks are the matter particles .


They make up all the things you see.


But things don't just exist, they also do stuff.

But things do n't just exist , they also do stuff .


In some philosophical sense, the properties of a thing are just as much a part of it as existence itself.

In some philosophical sense , the properties of a thing are just as much a part of it as existence itself .


This is where the bosons and the fields that make them come into play.

This is where the bosons and the fields that make them come into play .


While the quarks and leptons are made by matter fields, the bosons are made by force fields.

While the quarks and leptons are made by matter fields , the bosons are made by force fields .


We call a rule of the universe a force, and so far, four fundamental forces have been discovered.

We call a rule of the universe a force , and so far , four fundamental forces have been discovered .


These forces are the rulebook of a game where the pieces are particles and the game is the universe.

These forces are the rulebook of a game where the pieces are particles and the game is the universe .


They tell particles what they can do and how they can do it.

They tell particles what they can do and how they can do it .


Bishops move diagonally, massless particles move at the speed of light, knights can jump, gravity attracts.

Bishops move diagonally , massless particles move at the speed of light , knights can jump , gravity attracts .


The forces are the rules for how particles interact, which ultimately make them the rules for how particles assemble into all the big things we see in the universe.

The forces are the rules for how particles interact , which ultimately make them the rules for how particles assemble into all the big things we see in the universe .


Gravity isn't just the rule for orbits around the sun or apples falling from trees.

Gravity is n't just the rule for orbits around the sun or apples falling from trees .


As a rule, it says matter attracts, which builds planets and stars.

As a rule , it says matter attracts , which builds planets and stars .


Electromagnetism isn't just a rule for magnets attracting or repelling or electric currents in light bulbs.

Electromagnetism is n't just a rule for magnets attracting or repelling or electric currents in light bulbs .


It governs all atomic bonds, building every molecule.

It governs all atomic bonds , building every molecule .


Together, forces and particles are sort of like the Tinker Toys of existence.

Together , forces and particles are sort of like the Tinker Toys of existence .


The bosons are like messengers, passed between, you could say, connecting, the matter particles, which they use to tell each other how to move.

The bosons are like messengers , passed between , you could say , connecting , the matter particles , which they use to tell each other how to move .


Each particle uses a certain set of the forces to interact with other particles.

Each particle uses a certain set of the forces to interact with other particles .


Quarks, for example, can interact with each other with electromagnetism and the strong nuclear force, but electrons don't use the strong force, just electromagnetism.

Quarks , for example , can interact with each other with electromagnetism and the strong nuclear force , but electrons do n't use the strong force , just electromagnetism .


The quarks exchange strong force bosons, communicating the strong nuclear attraction to each other,

The quarks exchange strong force bosons , communicating the strong nuclear attraction to each other ,


while the protons they build exchange particles of electromagnetism, photons, with the electrons.

while the protons they build exchange particles of electromagnetism , photons , with the electrons .


Thus, the quarks end up locked up in nuclei, while the electrons remain attached by their electric attraction, building atoms.

Thus , the quarks end up locked up in nuclei , while the electrons remain attached by their electric attraction , building atoms .


if you zoom in far enough on anything, you just get 17 particles emerging from underlying fields, playing a game with four rules.

if you zoom in far enough on anything , you just get 17 particles emerging from underlying fields , playing a game with four rules .


To summarize, in the most basic form we know right now, this is what things are.

To summarize , in the most basic form we know right now , this is what things are .


This theory is what physicists call the standard model of particle physics.

This theory is what physicists call the standard model of particle physics .


You are basically nothing more than disturbances on an ocean that's excited by energy and guided by forces that make up the rules of the universe.

You are basically nothing more than disturbances on an ocean that 's excited by energy and guided by forces that make up the rules of the universe .


But why? And what is a force?


We'll have to explore a few more simple questions to get to the bottom of this.

We 'll have to explore a few more simple questions to get to the bottom of this .


We made some wallpapers from some of the graphics in this video.

We made some wallpapers from some of the graphics in this video .


You can get them on patreon.com.


If you want to help us make more videos, you can do so there.

If you want to help us make more videos , you can do so there .


We really appreciate your support.


While you decide, here are some more videos we made.

While you decide , here are some more videos we made .


Playing around with nuclear weapons in videos is fun.

Playing around with nuclear weapons in videos is fun .


There's a visceral joy in blowing things up and a horrifying fascination with things like fireballs, shockwaves and radiation.

There 's a visceral joy in blowing things up and a horrifying fascination with things like fireballs , shockwaves and radiation .


And while it does help put our destructive power in perspective, it's not the best way of understanding the real impact of a nuclear explosion.

And while it does help put our destructive power in perspective , it 's not the best way of understanding the real impact of a nuclear explosion .


This isn't about silly stacks of TNT or about how bright an explosion is.

This is n't about silly stacks of TNT or about how bright an explosion is .


Nuclear weapons are about you.


So we've partnered with the Red Cross and Red Crescent Movement to explore what would really happen if a nuclear weapon were detonated in a major city today.

So we 've partnered with the Red Cross and Red Crescent Movement to explore what would really happen if a nuclear weapon were detonated in a major city today .


We begin our story in the middle of downtown in a major city.

We begin our story in the middle of downtown in a major city .


People are going to work, studying for exams, are lost in their thoughts and daily lives.

People are going to work , studying for exams , are lost in their thoughts and daily lives .


Right here, a nuclear weapon is detonated and time freezes.

Right here , a nuclear weapon is detonated and time freezes .


The first phase of the explosion happens within less than a second.

The first phase of the explosion happens within less than a second .


In a millisecond, a ball of plasma hotter than the sun appears and grows in a fireball to more than 2 kilometers across.

In a millisecond , a ball of plasma hotter than the sun appears and grows in a fireball to more than 2 kilometers across .


Within this ball, everyone is just gone.

Within this ball , everyone is just gone .


Think of water dripped onto a very hot pan.

Think of water dripped onto a very hot pan .


All evaporated.


First, the flash, an intense tsunami of light, washes over the city in an instant.

First , the flash , an intense tsunami of light , washes over the city in an instant .


If you happen to have your head pointed in the direction of the explosion, it renders you blind for a few hours.

If you happen to have your head pointed in the direction of the explosion , it renders you blind for a few hours .


The heat of this light produces a thermal pulse, so energetic and hot that it just burns everything as far as 13 kilometers from the detonation site.

The heat of this light produces a thermal pulse , so energetic and hot that it just burns everything as far as 13 kilometers from the detonation site .


What this means is that everything in an area of 500 square kilometers that is able to burn starts burning.

What this means is that everything in an area of 500 square kilometers that is able to burn starts burning .


If you happen to be in reach of the thermal pulse, one moment you're on your way to work, the next moment you're on fire.

If you happen to be in reach of the thermal pulse , one moment you 're on your way to work , the next moment you 're on fire .


Now the second phase begins.


It happens in a few seconds.


Most people will now first notice that something is wrong, but it's already too late for hundreds of thousands.

Most people will now first notice that something is wrong , but it 's already too late for hundreds of thousands .


The flash is followed by the shockwave.

The flash is followed by the shockwave .


The heat and radiation of the fireball create a bubble of superheated and super compressed air around it that's now expanding explosively.

The heat and radiation of the fireball create a bubble of superheated and super compressed air around it that 's now expanding explosively .


Human infrastructure is no match for its power.

Human infrastructure is no match for its power .


Most major buildings within a kilometer of the fireball are just ground up down to their base.

Most major buildings within a kilometer of the fireball are just ground up down to their base .


Only steel reinforced concrete is able to partially resist the pressure.

Only steel reinforced concrete is able to partially resist the pressure .


In the surrounding parks where retirees feed the ducks, trees blackened and smoldering from the heat a second before snap like toothpicks.

In the surrounding parks where retirees feed the ducks , trees blackened and smoldering from the heat a second before snap like toothpicks .


If you're outside, you get tossed away like a grain of dust in a tornado.

If you 're outside , you get tossed away like a grain of dust in a tornado .


The shockwave weakens as it travels outwards,

The shockwave weakens as it travels outwards ,


Still, about 175 square kilometers of houses collapse like they're made of cards,

Still , about 175 square kilometers of houses collapse like they 're made of cards ,


Gas stations explode and fire spread throughout the rubble.

Gas stations explode and fire spread throughout the rubble .


A mushroom cloud made from the remains of the fireball, dust and ash, rises kilometers into the sky in the next few minutes and casts a dark shadow over the ruined city.

A mushroom cloud made from the remains of the fireball , dust and ash , rises kilometers into the sky in the next few minutes and casts a dark shadow over the ruined city .


This violently pulls in fresh air surrounding the city, destroying more buildings and providing an abundance of oxygen.

This violently pulls in fresh air surrounding the city , destroying more buildings and providing an abundance of oxygen .


It depends on the city what happens next.

It depends on the city what happens next .


If there's enough fuel, fires may turn into a firestorm that burns the rubble, everybody trapped in it and people trying to flee the devastation.

If there 's enough fuel , fires may turn into a firestorm that burns the rubble , everybody trapped in it and people trying to flee the devastation .


Up to 21 kilometers from the explosion, people just like you rush to their windows to take pictures of the mushroom cloud,

Up to 21 kilometers from the explosion , people just like you rush to their windows to take pictures of the mushroom cloud ,


The third phase begins in the coming hours and days.

The third phase begins in the coming hours and days .


We're used to the idea that help will come no matter the disaster.

We 're used to the idea that help will come no matter the disaster .


This time is different.


A nuclear explosion is like every natural disaster at once.

A nuclear explosion is like every natural disaster at once .


There are hundreds of thousands or millions of people with serious injuries, lacerations, broken bones, serious burns.

There are hundreds of thousands or millions of people with serious injuries , lacerations , broken bones , serious burns .


In the next few minutes and hours, thousands more will die because of these injuries.

In the next few minutes and hours , thousands more will die because of these injuries .


Countless people are trapped in collapsed buildings like in earthquakes or blinded by the flash,

Countless people are trapped in collapsed buildings like in earthquakes or blinded by the flash ,


They're terrified, confused and don't know what's happened to them or why.

They 're terrified , confused and do n't know what 's happened to them or why .


Most likely, many hospitals have been leveled along with all the other buildings and most medical professionals are either dead or injured along with everyone else.

Most likely , many hospitals have been leveled along with all the other buildings and most medical professionals are either dead or injured along with everyone else .


The survivors lucky enough to have been in metro tunnels or standing in the right place to be unburned and unhurt won't have truly escaped harm yet.

The survivors lucky enough to have been in metro tunnels or standing in the right place to be unburned and unhurt wo n't have truly escaped harm yet .


Depending on the type of weapon, where it explodes and even the weather, an awful black rain can begin,

Depending on the type of weapon , where it explodes and even the weather , an awful black rain can begin ,


The invisible, malicious, silent horror of radiation takes its turn.

The invisible , malicious , silent horror of radiation takes its turn .


Every breath carries poison to the lungs of the survivors.

Every breath carries poison to the lungs of the survivors .


Over the coming days, the people who receive the highest doses of radiation exposure will die.

Over the coming days , the people who receive the highest doses of radiation exposure will die .


There will be no help, not for hours or maybe even days.

There will be no help , not for hours or maybe even days .


Civilization doesn't operate when there is a total breakdown of infrastructure.

Civilization does n't operate when there is a total breakdown of infrastructure .


Help from surrounding cities will have a hard time entering the disaster zone and even if they can, the radioactive contamination will make it risky to get too close.

Help from surrounding cities will have a hard time entering the disaster zone and even if they can , the radioactive contamination will make it risky to get too close .


After a nuclear attack, you're on your own.

After a nuclear attack , you 're on your own .


So, bit by bit, people emerge from the rubble, on foot, contaminated with radioactive fallout, carrying what little they may have left.

So , bit by bit , people emerge from the rubble , on foot , contaminated with radioactive fallout , carrying what little they may have left .


They are slow, in pain, traumatized, and they all need food, water and medical treatment fast.

They are slow , in pain , traumatized , and they all need food , water and medical treatment fast .


And the damage done by a nuclear weapon doesn't end when the fires burn out and the smoke clears.

And the damage done by a nuclear weapon does n't end when the fires burn out and the smoke clears .


The hospitals in the neighboring cities are under-equipped for a disaster of this scale and overwhelmed with tens or hundreds of thousands of patients with serious injuries.

The hospitals in the neighboring cities are under - equipped for a disaster of this scale and overwhelmed with tens or hundreds of thousands of patients with serious injuries .


In the weeks, months and years to come, many of those who survived will succumb to cancers like leukemia.

In the weeks , months and years to come , many of those who survived will succumb to cancers like leukemia .


The reason no government wants you to think about all this is because there is no serious humanitarian response possible to a nuclear explosion.

The reason no government wants you to think about all this is because there is no serious humanitarian response possible to a nuclear explosion .


There's no way to really help the immediate victims of a nuclear attack.

There 's no way to really help the immediate victims of a nuclear attack .


This is not a hurricane, wildfire or earthquake or nuclear accident.

This is not a hurricane , wildfire or earthquake or nuclear accident .


It is all of these things at once, but worse.

It is all of these things at once , but worse .


No nation on Earth is prepared to deal with it.

No nation on Earth is prepared to deal with it .


The world has changed in the past few years, with world leaders again explicitly and publicly threatening each other with nuclear weapons.

The world has changed in the past few years , with world leaders again explicitly and publicly threatening each other with nuclear weapons .


Many experts think the danger of a nuclear strike is higher than it has been in decades.

Many experts think the danger of a nuclear strike is higher than it has been in decades .


Governments tell their citizens that it's good that we have nuclear weapons, but it's bad when anyone else gets them.

Governments tell their citizens that it 's good that we have nuclear weapons , but it 's bad when anyone else gets them .


That it's somehow necessary to threaten others with mass destruction to keep us safe.

That it 's somehow necessary to threaten others with mass destruction to keep us safe .


But does this make you feel safe?


It only takes a small group of people with power to go crazy or rogue, a small misstep or a simple misunderstanding to unleash a catastrophe of unimaginable proportions.

It only takes a small group of people with power to go crazy or rogue , a small misstep or a simple misunderstanding to unleash a catastrophe of unimaginable proportions .


Exploding stuff in videos is fun.


There is a solution though.


and the international Red Cross and Red Crescent movement, agreed to prohibit and eliminate nuclear weapons.

and the international Red Cross and Red Crescent movement , agreed to prohibit and eliminate nuclear weapons .


It's not about who has nuclear weapons and who doesn't.

It 's not about who has nuclear weapons and who does n't .


The weapons themselves are the problem.

The weapons themselves are the problem .


They are deeply immoral and an existential threat to all of us.

They are deeply immoral and an existential threat to all of us .


No matter what country you come from, no matter what political side you find yourself on, we need to demand that they disappear forever.

No matter what country you come from , no matter what political side you find yourself on , we need to demand that they disappear forever .


This will not happen without pressure.


If you want to be part of this pressure, there are things you personally can do too.

If you want to be part of this pressure , there are things you personally can do too .


Visit notanukes.org to learn more about nuclear weapons and what you can do about them.

Visit notanukes.org to learn more about nuclear weapons and what you can do about them .


What would happen if we were to detonate a very, very powerful nuclear weapon on the Moon?

What would happen if we were to detonate a very , very powerful nuclear weapon on the Moon ?


Would the explosion knock its orbit towards Earth, causing tidal waves and misery?

Would the explosion knock its orbit towards Earth , causing tidal waves and misery ?


Could the Moon be destroyed, showering the Earth in a rain of meteoric death?

Could the Moon be destroyed , showering the Earth in a rain of meteoric death ?


During the Cold War, the Moon was a major target for space exploration and, you know, military bases.

During the Cold War , the Moon was a major target for space exploration and , you know , military bases .


So, the US Air Force commissioned a serious study into the effects of a nuclear detonation on the surface of the Moon.

So , the US Air Force commissioned a serious study into the effects of a nuclear detonation on the surface of the Moon .


But just quoting stuff is boring, so let's conduct a very important scientific experiment with an imaginary 100 megaton thermonuclear warhead

But just quoting stuff is boring , so let 's conduct a very important scientific experiment with an imaginary 100 megaton thermonuclear warhead


We'll also place a number of curious astronauts around the Moon as observers.

We 'll also place a number of curious astronauts around the Moon as observers .


Let's push the button and slow down time.

Let 's push the button and slow down time .


For the first few milliseconds, nothing much happens outside our weapon.

For the first few milliseconds , nothing much happens outside our weapon .


Meanwhile, inside, high explosives send a shockwave to a radioactive metal core, compressing it so much that it reaches criticality and starts a nuclear fission chain reaction.

Meanwhile , inside , high explosives send a shockwave to a radioactive metal core , compressing it so much that it reaches criticality and starts a nuclear fission chain reaction .


The 100 million degree plasma created in this first stage sets off the second stage with atomic nuclei fusing like they do in the core of a star.

The 100 million degree plasma created in this first stage sets off the second stage with atomic nuclei fusing like they do in the core of a star .


Very briefly, our weapon contains one of the hottest places in the Universe.

Very briefly , our weapon contains one of the hottest places in the Universe .


And only now, barely 10 milliseconds later, does the rest of the Universe find out that anything has happened as suddenly the bomb dissolves and a flaming star of nuclear death is born.

And only now , barely 10 milliseconds later , does the rest of the Universe find out that anything has happened as suddenly the bomb dissolves and a flaming star of nuclear death is born .


But everything that happens now is very different from what we're used to on Earth because of one major difference.

But everything that happens now is very different from what we 're used to on Earth because of one major difference .


There's no atmosphere.


As the fireball shines, it releases a flash of X-rays and thermal photons, a wave of silent heat which rushes outwards in all directions.

As the fireball shines , it releases a flash of X - rays and thermal photons , a wave of silent heat which rushes outwards in all directions .


On Earth, this heat would char and burn everything within a 50 km radius at least.

On Earth , this heat would char and burn everything within a 50 km radius at least .


But on the Moon, without an atmosphere and oxygen-rich air, there's no burning at all.

But on the Moon , without an atmosphere and oxygen - rich air , there 's no burning at all .


Also, there are no things to burn.