Nuclear Historian Answers Nuclear War Questions

I'm Alex Wellerstein.

I'm a nuclear historian.

I'm here today to answer your questions from the internet.

This is Nuclear History Support.

[upbeat music]

All right, first up, we have one from @AmericanVsGov.

What countries have nukes?

There are nine countries today in the world

with nuclear weapons that we know about.

The United States, first country that got them.

The Soviet Union got them in 1949.

Today, those nuclear weapons are in the hands

of the Russian Federation.

The United Kingdom, People's Republic of China, France.

These are the five officially allowed countries

under the nuclear non-proliferation treaty

to have nuclear weapons.

There is also Israel, India, Pakistan, and North Korea,

so nine countries total.

There were a few countries that inherited nuclear weapons

after the fall of the Soviet Union,

Ukraine, Belarus, and Kazakhstan,

but they returned all of those weapons

to Russia in an agreement.

LJWhitman1, asks, Who decides which countries

can have nukes and which countries can't?

What are their criteria?

The decision about who can quote, unquote, have nukes

and who quote, unquote, can't,

this is the result of a treaty,

the Nuclear Non-Proliferation Treaty,

which was created in 1968

to try and slow the spread of nuclear weapons.

If you sign the treaty, you agree that only five countries,

the countries that had tested nuclear weapons by 1967,

are allowed to have nuclear weapons.

Anybody else is not allowed under that treaty.

So if you sign that treaty,

you agree those are the only five that have nuclear weapons

and nobody else should have.

Pakistan, India, and Israel never signed the treaty,

have developed their own nuclear weapons.

There's also North Korea, which was a member of the treaty,

but then left the treaty and made nuclear weapons.

Is it illegal for them to have nuclear weapons?

Only in the sense that they're not members of the treaty.

What the nuclear Non-Proliferation Treaty does

is it allows any country without nuclear weapons

to know that anybody else who signed the treaty

is probably not also trying to get nuclear weapons.

So if you're worried that your rival across the way

might be getting nukes,

if you and they both signed the treaty,

then you're not going to have to worry as much

about them getting the weapons.

It also gives them access

to peaceful nuclear technology like nuclear reactors.

It means that they have the right

to work on that kind of stuff

without worrying that somebody's gonna try

and, you know, blow up their reactor

out of fear that it's a nuclear bomb.

zipthwung asks, Was Iran building a bomb?

If so, how close to a bomb was Iran?

How were the nuclear talks going

before Israel preemptively attacked?

Great question. Was Iran building a nuclear weapon?

No, I don't think anybody thinks Iran

was actively building a nuclear weapon.

The accusation, made particularly by Israel,

is that Iran was setting up the conditions

under which it could build a nuclear weapon

very quickly if it wanted to.

Iran did have a nuclear weapons program before 2003,

and the Iran deal was them essentially saying,

We're gonna close down

and disable all the little things we were doing

that were bad and we won't do them anymore.

Once the United States left the Iran deal,

Iran has been creeping up beyond the limits of the deal.

You know, depending on what your stance is,

you either think that's because

they are trying to get ready to make a bomb,

or because they're trying to compel the United States

to come back to the negotiation table as a way of saying,

Look, if you leave this deal, which we did,

we can do this now,

and if you want us to stop, come back to the deal.

Now, how are the nuclear talks going?

I don't think that great.

I don't think it's clear exactly what Iran wants, per se.

They're sort of leaving the door open for different options,

which would make a lot of sense

given the recent history that they've had

with the United States and with Israel,

but they were not, you know, racing to make a bomb.

hellherekitten asks, WTF is a nuclear football?

It's basically a suitcase.

What the nuclear football is meant to do

is allow the president of the United States

to order a nuclear strike

even if they are not in the White House or the Pentagon.

If the president is visiting some other country

or some other city, they have basically

a very burly, usually, military person

carrying a very heavy suitcase around.

And in that suitcase,

there are information about nuclear war plans.

There are some communication tools probably

to allow the president

to easily link up with top generals and advisors

and whatever is needed

to authenticate the president's nuclear war order

if the president decides to make that.

Sophikkelson asks, Once in a while,

I think about how many nukes the US has lost.

How tf do you lose a nuke?

Find them now.

There are a number of quote, unquote, lost nuclear weapons,

and what that really means is there is a nuclear weapon

that was on say, an airplane or a submarine,

and that airplane either crashed or the submarine sunk,

and the weapon is now in the environment, in the world.

These kinds of accidents

were not super uncommon during the Cold War.

The United States had a program in the 1950s and 1960s

to basically have airplanes with nuclear weapons

flying in the air 24 hours a day, seven days a week,

so that if nuclear war started,

they could have some kind of guarantee

that they'd have a plane ready to retaliate no matter what.

Same thing with submarines.

They still go around

with nuclear weapons on them all the time.

If you have thousands of airplanes

flying tens of thousands of flight hours,

you're gonna have an accident every once in a while.

Some of these accidents have resulted

in like the weapon either itself falling out of the plane,

or in the case of a submarine,

just going down to the bottom of the ocean.

Any kind of mishap you can imagine,

a lot of them have happened.

In most cases, of course, the United States

is very interested in recovering those weapons,

both because it's, you know, not a good look

to have lost nuclear weapons,

but also they contain the fuel you might need

to make more nuclear weapons

and you don't want that falling in the wrong hands.

And so the US always tried to recover these things,

but sometimes the warhead sunk so deep underground

that after weeks of trying to dig it out,

they couldn't get it or it's at the bottom of the ocean

and they couldn't find it.

They're lost in the sense that the US can't recover them,

not that they don't know, more or less, where they are,

and they're lost in the sense

that the US couldn't recover them

and thinks nobody else could either,

and decided to sort of cut their losses

and, you know, maybe they put a monument that says,

Don't dig here.

But they concluded

that if the army couldn't dig this thing up,

nobody else could either.

Matilda_Mother_67 asks,

Why did the United States bomb Hiroshima and Nagasaki

instead of some military headquarters

or other places where civilians weren't?

There were a lot of processes and meetings

and decisions made along the way

about what this bomb was, how it should work,

what it would be used against.

At the beginning of making the bomb, like say 1943,

the attitude was, We'll probably use this

against some sort of military installation.

The first target they even discussed

was basically the Japanese equivalent of Pearl Harbor,

it's called Truk.

And sure, there would be some civilians there,

but it's not dropping it in the middle of a city.

By 1945, 2 years later,

one, Truk is not an issue militarily anymore.

They had cut it off. It was not a target.

And two, the United States had gotten in the habit

of targeting cities.

In the early part of 1945, the United States

began firebombing Japanese cities with napalm.

They burnt Tokyo, they burnt Osaka.

They ended up burning 67 Japanese cities

by dropping basically flaming gasoline on them.

The other issue is that the bomb they ended up with

was one that would work best

if you detonated it pretty high in the air.

If you detonate it high in the air,

you spread the blast damage out wider,

but your blast damage is also less intense.

So if your target is some built-up bunker,

you're not gonna destroy it

by blowing up the bomb in the air.

If your target is a house,

you don't need as much blast pressure to destroy it.

So they had a bomb that they ended up with,

through technical decisions along the way,

that would be most impressive if you used it on a city.

And they had many discussions about what kind of target,

what's the goal of this weapon.

The goal of the weapon was essentially psychological.

They wanted to cause the Japanese people

to say, We cannot tolerate this.

We cannot win. Let's surrender.

One of the people involved in the discussion

said that the goal was to have the Japanese

basically capitulate to the power of the universe.

Oh, you don't wanna surrender to the United States

or the Soviet Union?

Well what if we use the power of the sun to destroy you?

To me, the really interesting thing is that Hiroshima

was not their first choice at all for a target.

The first choice that the military had was Kyoto,

former capital of Japan.

It was taken off the list by the Secretary of War,

Henry Stimson, because he thought

that the city was too civilian in nature,

was a cultural heritage site.

Hiroshima got then bumped up to first place

because it had some military bases

and manufacturing in it.

It had not yet been bombed.

Its geography was such that it was

sort of like a bowl-shaped city surrounded by hills,

and that meant it would kind of intensify

the effect of the weapon.

So from the point of view of the United States military

and the scientists who consulted from them,

it was a perfectly good target.

Nagasaki was only added to the target list

after Kyoto was taken off of it

because they wanted a backup target.

The actual target for the second bombing run

was a different city, Kokura.

Kokura had a major arsenal in the center of it

that produced weapons for the Japanese

and was surrounded by workers' houses.

So by their criteria, this was a great target.

When they got to Kokura though,

they found that it was covered by smoke or clouds or haze.

It's not clear exactly what.

But they could not see it to exactly target the bomb on it.

So they went to the backup target,

which was Nagasaki, which was nearby.

matthewswaite asks, I can't help

but think gun control debates

mirror that of nuclear weapons proliferation.

Does every country having nukes make us all safer?

This is a classic question.

Is the world safer if there are only

a couple countries with nuclear weapons

or would it be safer if all the countries

had nuclear weapons?

If there were a lot of countries with nuclear weapons,

presumably they would be very hesitant

to go to war with one another

because the consequences would be terrible.

On the other hand, if you think that the chances

of either accidental nuclear war

or people thinking nuclear war was winnable,

or terrorism, if you think the chances

of those are relatively high,

then more nuclear weapons in the world

is a much more dangerous world

because that's a world in which nuclear war

is more likely to occur.

It's not clear what the answer is here.

Generally speaking, I'm more swayed by the arguments

that is a little bit dangerous

to have lots of countries with nuclear weapons in the world.

I know that's a really hot take,

but I don't trust the systems

or governments of these countries to be sort of perfect

with regard to they're not starting a nuclear war.

And if you don't think that they're going to be perfect,

then it becomes very dangerous over time,

the more people who have nuclear weapons.

Huge_Bag69 asks, Enriched uranium, what is it?

What is the process of enriching?

How dangerous is it on its own?

So uranium is an element.

You can mine it out of the ground.

It's a rock.

You can even get it out of sea water.

It's relatively abundant.

By itself, if we went out and got a rock of uranium,

the uranium we would find

would have two types of uranium inside of it.

One of 'em would be called uranium-238.

There would be 99% of that

in any uranium we pulled out of the ground.

And less than 1% of it,

it's like 0.7% would be uranium-235.

So these are two of the same element,

but they differ in that uranium-238 has three more neutrons

inside of it than uranium-235.

So we call these different isotopes.

Uranium-238 will not explode in a bomb.

Uranium-235 will.

So enrichment is when we take this uranium

and pull out the uranium-235,

almost literally atom by atom.

This is a very difficult process to do

because the difference between these

is only three neutrons, which is not very much.

They are chemically identical.

So we have to rely on the fact

that one's a little bit lighter than the other.

So uranium enrichment,

there's different processes for doing it.

And the most famous right now is the centrifuge

where we basically are spinning

around uranium in a gaseous form,

and as we spin it,

the centrifugal forces will cause the lighter uranium

to move slightly and more one direction

and the heavier slightly another,

and we skim off the part that would have the lighter.

And we have to run it through another centrifuge

to skim off a little more

and then another to skim off a little more.

And so we're taking advantage

of little tiny statistical differences

in how heavy they are.

And we do this for thousands of centrifuges

and you will eventually end up

with more and more uranium-235.

When we want uranium for fuel in a nuclear power plant,

we tend to enrich it up to about 3% uranium-235.

When we want it for a bomb,

we want it to be much higher than that.

The bomb dropped on Hiroshima

was about 80% uranium-235.

In the United States now, the standard amount in a weapon,

if we use enriched uranium, is around 93% enriched uranium.

The4thResident asks, Wait, but Einstein

was not a part of the Manhattan Project,

so how or why did they get his help during it?

Einstein's role in the atomic bomb

was at the very beginning.

He wrote a letter to President Roosevelt saying,

Hey, we have learned how to split atoms.

Germany might be working on this.

Maybe somebody in the United States government

should be looking at this.

And that's more or less

his role in the whole Manhattan Project.

Why didn't they use him?

They actually did consider using him

and they concluded two things.

One, Einstein at this point is pretty old.

He's not your cutting-edge scientist.

The kind of science he does

is not actually that useful for making an atomic bomb.

Yes, yes, =mc2 sort of explains, in a way,

where the energy comes from an atomic bomb.

It does not tell you how to make one.

It doesn't tell you how to make a factory

and design the things and the parts.

You don't need somebody like Einstein to do that.

The other thing is that Einstein

was considered politically radical.

He supported really out-there ideas like civil rights.

And that, at that time, meant that he was considered

to be politically questionable

by some people in the US government.

And so if he is the kind of person who,

to be fair, might have strong ideas

about how atomic bombs ought to be used

and has a lot of fame

and is the kind of person that presidents would listen to,

maybe you don't want him to be in the project

if your goal is to just sort of get the thing done.

CoastalBuckeye asks,

Is there still a radiation field in Hiroshima or Nagasaki?

Great question.

Hiroshima and Nagasaki had atomic bombs dropped on them

in World War II.

Here's Hiroshima. This is not far from ground zero.

You can see this building, the very famous Atomic Bomb Dome,

ground zero is very close to that.

These weapons were detonated very high above the city.

If you look at pictures of these bombs,

this is a mockup of the kind of bomb dropped in Hiroshima.

This is one for Nagasaki.

You can see they've got this equipment on them,

weird little wires.

These are fuses that detect

how high above the ground the bomb is,

and they were set to detonate at the height

that the scientists had calculated

would maximize the blast effect of the weapon.

You can think of the blast

as going sort of as a sphere out from the explosion.

And if it's really close to the ground,

a lot of that is gonna be going sort of sideways

and it's gonna be running into buildings

and they're gonna be absorbing the energy

and also reducing it as a consequence.

If you detonate it in the air,

you're sort of going down with the blast force

and it's gonna be much wider area.

So it was detonated high in the air.

The consequence of that is the people

at Hiroshima and Nagasaki,

they got a blast of immediate radiation.

It's like almost like a light switch turning on and off.

You wouldn't be able to see it,

but imagine it's just like a quick exposure,

almost like X-rays or something like that.

And that was very bad for the people

who were in the range at which that would occur.

But it's a short immediate effect.

It's sort of almost like a one-time exposure.

The thing that makes nuclear weapons so contaminating

is the nuclear fallout.

These are the split atoms from the weapon

and these are in the mushroom cloud.

And one interesting thing

you can actually see in some of these pictures,

so this is a picture of Nagasaki's mushroom cloud

taken from someone on the one of the airplanes

that was involved in the bombing of Nagasaki.

And if you look closely,

you can see the cloud is actually two different parts.

You have this top part, the head,

and then you have this dark stem underneath it,

and you can actually see that they don't connect.

This is an artifact of the weapon being detonated higher up.

This cloud contains

the most radioactive residues from the bomb.

This is mostly created by fire and debris

and dust that is being pulled up

by the negative pressure of this cloud moving upwards.

And it is not that radioactive.

Now, if this bomb had been detonated on the ground,

these two parts would be mixed together.

And if that happens,

then the radioactive bits attach themselves to the dirt

and then fall out of the cloud relatively quickly

because the dirt is pretty heavy, relatively speaking.

If it doesn't happen, this part stays relatively light

and it'll blow on with the wind

and as it blows, it'll take a while

for it to start to fall out of the cloud.

And what that gets you is two things.

One, the most radioactive stuff with short half lives,

they get to sort of burn out before they fall down.

But this cloud, because it has time to spread,

it means that it's diluting.

So more area gets some radioactive bits,

but they get less like per square meter, per square foot.

So the amount of radiation is diffused in a way

that doesn't actually make it a contamination hazard.

So the long and short of it

is because they're detonated at high altitude,

they did not really get a lot of nuclear fallout.

Today, they are not radioactive in any significant way.

If the bombs had been detonated on the ground,

it would be a different story.

xjsscx on Reddit asks, What actually happens

to someone in an atomic bomb explosion?

The first thing, if you saw a nuclear weapon go off,

one, the brightness of it, it's very bright.

With that brightness comes this flash of radiation.

So if you are close enough to an atomic bomb,

you will instantly get a lot of radioactive particles,

gamma rays, beta particles, things like this

going through your body.

For the Hiroshima bomb,

the radius from the detonation point

where you get a fatal amount of radiation

is about three quarters of a mile.

If you're in that zone, you're probably dead

no matter what happens next.

If you're a little out of that zone,

you might get some radiation.

That is probably not your biggest concern

for most nuclear weapons, but it's not the best, right?

The next thing that you would experience is heat.

The surface of the fireball is hotter than the sun.

Briefly.

If you're in direct line of sight with this,

it's sort of like if the sun

was suddenly a lot closer to you than it is right now.

If you're really close to the fireball,

you could be literally vaporized as people say.

Most of the people at Hiroshima Nagasaki are not vaporized

or melted or anything, but they were severely burned.

You can get really bad burns.

The next effect,

that fireball in that first split second of it going off,

is sort of super-heating the air around it.

And what's gonna happen then

is it's going to be moving outward.

This is the shock wave, the blast wave.

And as it goes out, it's this sort of wave of pressure

that's going to intersect with the ground

and move along it and push,

and the more it goes, the weaker it goes.

But this is powerful enough at different distances

to do a lot of damage.

So at Hiroshima,

if you were about 300 meters from ground zero,

that would be enough blast pressure,

about 20 pounds per square inch,

to destroy almost any building that is standing.

Any buildings that are still remaining at Hiroshima,

like the famous Atomic Bomb Dome, are gutted.

Like nobody's doing well who was inside this building.

They're all dead.

If you go out a little further,

if you were about 1.7 kilometers

from ground zero at Hiroshima,

that's the radius at which there's enough

to definitely destroy light structures.

So houses, things like that.

You go out further to maybe about 2.8 miles,

and now the blast wave is weak enough

that the most it's doing is sort of breaking windows.

That's still not great.

If you're standing at a window as this thing comes to you,

it's gonna break all the glass and push it into you,

and now you've been injured by a window.

So depending on where you are,

there's different effects that can happen.

Stranfort asks on Reddit,

For how long do I stay in a fallout shelter

after a nuclear war?

The amount of time you need to stay in there

depends on how radioactive the fallout is.

Now a lot of people think of fallout shelters

like the game or show Fallout,

and they think we're gonna stay in there

for a hundred years or something like that.

That is not what they're built to do.

They are built to basically accommodate people

to maybe stay in there for at most two weeks,

maybe even less.

You might recognize these signs.

These are from the 1960s program

to identify places that could be used as fallout shelters.

A fallout shelter is not meant

to protect you from a nuclear weapon that drops on you.

What it's meant to do is be a place

that puts mass, so concrete or dirt ideally,

in between you and the outside world

so that if radioactive particles fall on top of you,

there is something in between you and them

to cut the amount of radiation.

So you can think of it when you go to the dentist

and they take an X-ray

and they put one of these heavy lead aprons on you.

It's sort of like a building equivalent of that lead apron.

Mac60five asks, How dangerous is Chernobyl Today?

There are people who visit Chernobyl

or did before the Ukraine-Russia war.

There are people who work at Chernobyl still today,

and they have means of checking

how much radiation they pick up.

There are tools called dosimeters.

This is one from the Cold War.

It basically tracks how much radiation you get.

This one works by looking through it at a light

and a little wire moves as it absorbs radiation.

And the workers on these kinds of places

are making sure that the amount of radiation they pick up

is within what we consider to be the safe amounts.

You probably wouldn't wanna live in Chernobyl though.

There are some people who have been living there,

people who used to live there

that eventually went back and they've said,

You know what? I just wanna live in my own home.

I don't care if it's contaminated.

Are they at risk?

Well, a little.

But if they're 70 years old and living at Chernobyl

increases their cancer risk by say 5%,

they're probably gonna die of something else anyway

because it takes a long time

for those kinds of cancers to develop.

If we talk about, what if 10,000 people lived there

and the cancer risk goes up by 5%,

you're gonna start seeing that

as 5% more cancers in this community than you would already.

austinsburner asks, How tf does radiation work?

How does a place be radioactive?

How does someone die from radiation poisoning?

You can think of it as little particles.

That's basically what the word radiation means.

It means little things spitting out.

And there's lots of different kinds of radiation.

The kind that people are usually talking about

is called ionizing radiation, and that means radiation

of types and energies that are capable

of knocking electrons off of other atoms and molecules.

The problem is that if you're made out of cells,

and especially if you have DNA,

ionizing things, that changes their chemistry.

And if you were a rock, who would care?

But if you're a biological system,

that means you're like shooting little bullets into cells

which can kill them, which is fine.

You have a lot of cells.

Or it can, in some rare cases,

change the DNA in a way that turns it into a cancerous cell.

Radiation poisoning is when you get so much radiation

that the number of cells you're killing

becomes actually significant.

So radioactive contamination is when a place

has radioactive stuff that is sending out the radiation.

So I have a Geiger counter here.

A Geiger counter is a tool for detecting radioactivity.

So what it has in it is a sensor that can tell

when a radioactive particle has gone across it.

And whenever it does this,

you're hearing this little click happening.

Why does it click?

Because we hooked it to a speaker

and we wanna be able to hear it.

Now I could have a radioactive substance.

This is trinitite, the glass from the first nuclear test.

This is something that contains trace amounts

of plutonium and uranium

and long-lived fission products.

And if I put the sensor over it,

[Geiger counter clicks]

you can hear that the clicking increases by a bit.

The air right above this radioactive material

is getting about twice as much radioactivity

as the normal air around here.

That's not that much.

If this was something actually dangerous,

it would be getting a lot more, a hundred times more.

But this is the sort of tool

that lets you measure when these radioactive particles

are being emitted from this radioactive substance.

GlitteringWeakness88 on Reddit asks,

What is the theoretical upper power limit

of a nuke we can produce currently?

If you wanted to,

you can make essentially an unlimited power nuclear weapon.

A thermonuclear weapon basically works

by having one nuclear weapon act

as sort of the detonator for another nuclear weapon.

And if you wanted to, you could make

that weapon be the detonator for another nuclear weapon.

And that detonator for another nuclear weapon.

The largest nuclear weapon ever made

was the Soviet Tsar Bomba.

It was tested in 1961 as a 50-megaton-sized weapon,

so 50 million tons of TNT,

and that was at half its power.

It was deliberately scaled back by half

to prevent contamination.

By comparison, the Hiroshima bomb

is 15,000 tons of TNT.

So this is a weapon thousands of times more powerful

than the first atomic bombs.

The United States could have done that.

They actually looked into doing

that kind of thing in the Cold War and decided not to.

So the largest weapon that I know of

that was ever taken seriously

by weapon scientists in the United States

was called the Sundial.

It was never built.

They didn't get that far in researching it.

But it was a weapon that was 10,000 megatons of TNT.

Why did the United States not do this?

Why did even the Soviet Union not really do this?

The Tsar Bomba was sort of a stunt

more than a practical weapon.

The answer is, one, you don't get that much from it.

Because of the way nuclear weapons work,

because they're basically a sphere expanding in the air.

Think of it as a balloon that you're like pumping air into.

What we care about for the damage

is the amount of the balloon that's gonna touch the ground.

A lot of that balloon is not gonna touch the ground.

And as we're putting energy into it,

the part that's touching the ground,

it's not increasing as a linear function.

It's increasing as what's called a cubic root.

The takeaway is,

if we wanted to double the damage of a weapon,

we typically have to increase the size of the weapon

by around eight times.

The real killer though is, to make them bigger,

we do more or less have to linearly increase the weight

and size of the weapon.

So the Tsar Bomba is a powerful weapon,

but it's the size of a school bus.

That weapon could not fit inside

the airplane that carried it

and had to sort of sit underneath it like a big egg.

If you are another country

and you see a plane coming towards you

with a big egg attached to it,

you're gonna really work hard to shoot that down.

That is not convenient.

If you're talking about weapons

that are the size of the Sundial, 10,000 megatons,

that's a weapon that's probably

the size of the space shuttle.

That's not easy to use. That's not easy to deploy.

That's gonna be also really expensive as an aside.

Trends in nuclear weapons design didn't go in that area.

What they did was they went for more compact weapons

so you can put 10 of them onto one missile

and then target 10 targets with one missile.

It's a weapon the size of a large trash can,

but it's 30 times more explosive than Hiroshima.

That's peak weapons design, not just more bang.

Perfect-Football2616 on Reddit asks,

Did the tactic of duck and cover

provide any protection from an actual nuclear strike?

Duck and Cover was a public education program

put out by the United States government,

and it was particularly aimed at school children.

And you'll see pictures

of children hiding under their desk from this period.

There was a short film created

with a turtle cartoon mascot, Bert the Turtle,

trying to talk to students about nuclear war.

And, of course, a lot of it looks pretty sketchy.

There are lots of people who lived through this who said,

That was the moment I realized

adults did not know what they were doing

if they thought this desk

was gonna protect me from an atomic bomb.

They are not saying

that if an atomic bomb lands on your school,

your desk is gonna keep you safe.

What they are doing with this policy

is saying there's gonna be an area where the bomb goes off,

where you just have no hope.

I'm sorry.

They don't say this in the movie

because it's aimed at children.

They don't even say this things aimed at adults

because the United States government

has a very hard time admitting

that people are gonna die in large numbers

if nuclear weapons go off,

even though it is self evidently true.

There's also a zone much further out

where you're far enough away that you'll say,

What was that? Oh my gosh, what's going on?

You are not going to be affected by the weapon, right?

You're gonna learn from the news.

So in between is a pretty small zone

where you have a chance of surviving

if you do the right thing.

Duck and Cover is for that zone,

and it's for an area where the blast pressure

is going to be enough

that it is gonna be sort of like an earthquake.

They're worried about the ceiling collapsing,

they're worried about windows breaking.

They're worried that if you have exposed skin,

you might get burned.

And so the tactic is get down,

cover up your most vulnerable parts,

and you can increase your chance of survival

a little bit that way.

TheMuteNewt on Reddit, great name,

How close did Nazi Germany actually get

to developing an atomic weapon?

Nazi Germany did not get close

to making an atomic bomb.

At the end of World War II they were almost to the place

that the United States was in 1942.

So they almost had a prototype nuclear reactor,

not an atomic bomb.

Why not? Because they weren't trying to make an atomic bomb.

I know that's a hot take

because we like to talk about the race for the atomic bomb.

The Americans feared they were working on atomic bomb,

but the Germans had actually decided they were gonna have

a pretty small research program for nuclear reactors,

maybe in the future, making atomic bombs.

But they concluded in 1942

that it would take a lot of work

from a lot of their scientists

to try and make an atomic bomb

that could be useful for World War II.

And in 1942, they thought they were gonna win the war

so they didn't think they needed an atomic bomb.

They thought that making an atomic bomb

would be very hard and they were correct on that.

And as a result, they thought nobody else

was gonna make one either.

So this is a problem for after the war.

Well, that's it. That's all the questions.

I hope you learned something.

I hope you don't make an atomic bomb.

Until next time. [upbeat music]