June 22, 2023 • 52 mins
Daniel and Katie touch on the explosive question of nuclear weapons and explain the impact of space-based explosions.
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Speaker 1 (00:08):
Hey, Katie, what's the biggest thing that you've ever seen
blow up?
Speaker 2 (00:12):
Technically soup that I microwaved too high, But I've always
wanted to see one of those building demolitions.
Speaker 1 (00:20):
Oh, that does sound fun. I'd love to see you
blow up soup or watch a building get exploded. I
wonder if they sell tickets to those events.
Speaker 2 (00:27):
I hope they go on tour, and I hope they
come to my city. What about you, what is the
biggest explosion that you have seen?
Speaker 1 (00:35):
Well, there was the time that I made a strawberry
smoothie without putting a lid on the blender and I'm
still cleaning up strawberry in the kitchen years later. But
I did once see a shoe store explode when an
air and firework hitted on New Year's Eve. It was crazy.
You could feel the heat from blocks away.
Speaker 2 (00:53):
That's crazy, that's amazing. I'm sure you were going to
say something more dramatic, though.
Speaker 1 (00:59):
More dramatic than a flaming shoes door, but.
Speaker 2 (01:02):
I thought so you grew up in Los Alamos, Like,
isn't that the home of the atomic bomb?
Speaker 1 (01:08):
It is, but we don't just like set them off
on holidays.
Speaker 2 (01:12):
That seems like a shame.
Speaker 1 (01:14):
I guess you could say we've kind of blown it.
Speaker 2 (01:18):
You didn't blew it, and that's the problem.
Speaker 1 (01:35):
Hi. I'm Daniel. I'm a particle physicist and a professor
at UC Irvine, and I hope to never be near
a nuclear explosion.
Speaker 2 (01:43):
I am Katie Golden. I host the podcast Creature Feature,
and I hope there's never a nuclear explosion anywhere ever, space, Earth,
what have you? It seems like a bad sign of
things to come.
Speaker 1 (01:59):
Are you saying that nukes can never be used for good?
You're not aware of the Peacetime nuclear weapons program or
the design of the Orion spaceship, which literally uses nuclear
weapons blowing up behind it in order to propel it forward.
Speaker 2 (02:13):
I mean, if you're basically gonna do big space farts
with nukes to make your spaceship go, I'll make an exception.
Speaker 1 (02:22):
All right. We have already broken down your barriers here
and so welcome to the podcast. Daniel and Jorge Explain
the Universe, a production of iHeartRadio in which we dive
deep into everything that happens in the universe, how it
all works, how it all began, how it all might end,
and how humans might bring about their own demise.
Speaker 2 (02:42):
I'm a big fan of life on Earth. I love
all the animals on Earth, love all the plants, and
the humans, most of them, ninety nine percent of humans.
And you know, I have a lot of nuclear anxiety
when it comes to the planet Earth, because I don't
want one going off and you know, destroying a bunch
(03:04):
of stuff, radiating things, maybe causing a new ice age
with the clouds of debris. But I guess if it's
blown up in space, I'm a little less worried.
Speaker 1 (03:16):
Well, this to me is a really interesting area because
it brings together the sort of fascinating progress we make
in physics as we start to understand the way the
universe works, what the forces are that underlie everything, how
they weave themselves together to make our reality. Understanding that
also gives us new power, the power to use that
knowledge to develop new technologies, which of course can be
(03:38):
good in peace time, like transistors and iPhones, but also
can be used to make weapons of mass destruction that
are pointed at civilian populations for political gain. And so,
while we like on this podcast to think about the
physics side of it, the scientific edge of knowledge, how
we can always push that forward, and we generally think
about that knowledge as purely good as sausfying our curiosity
(04:01):
is scratching our itch that wonders about how the universe works.
It's not possible to really live in a bubble and
pretend that that knowledge can't be used in all sorts
of ways that the original scientists who worked on it
aren't in control of. Personally, I did grow up in
Los Alamo's home in the Manhattan Project in Los Almos
National Laboratory, where weapons projects are ongoing to this day,
(04:23):
and both of my parents worked at the lab and
worked on weapons related projects. What exactly they did, I
don't know. I didn't know. I will never know, because
I don't have particular rants to know such secrets. But
such power over the universe comes with real responsibility.
Speaker 2 (04:38):
Yeah, I think I remember that a lot of these
scientists who worked on the Manhattan Project became very anti
nuclear proliferation. You know. It's it's something that I think
people who really understand the devastating power of nukes also
are very much opposed to uncontrolled proliferation of dukes. I
(05:00):
don't think it's something where scientists are There's a bunch
of mad scientists who really just want to blow up
the planet. I think most of the scientists who really
understand this stuff are also probably pretty anxious and would
like a world with fewer nukes.
Speaker 1 (05:15):
Yeah. Absolutely, I do know that my mother worked on
nuclear non proliferation programs, ways that you can detect nuclear
fuel and nuclear explosions, et cetera. But my father definitely
worked on the weapons side of it. And I asked
him once, not, of course, like tell me some nuclear secrets,
but how do you feel about working on the design
of huge weapons that are in the end pointed at
(05:36):
civilian populations. And you know, back in the eighties when
he started that job, it was a different era. We
were still in the Cold War and developing our nuclear capabilities.
Sort of felt patriotic. Back then, it felt like, Hey,
you're contributing to your country, you're protecting us, you're defending us.
I'm not saying that it's morally crisp and clean. I
certainly chose to do particle physics because it has no
(05:58):
weapons applications, and nobody's ever use my research to kill anybody.
Speaker 2 (06:02):
Not yet, they haven't yet. Give me a pen and
a piece of paper, I'll come up with something that's.
Speaker 1 (06:09):
Right, The Higgs Boson bomb by Katie goldd Well. Nuclear
weapons are very powerful and very dangerous, and they have
also captured the public imagination and I get a lot
of interest in our podcast email box about nuclear weapons.
People wonder what would happen if you dropped the nuclear
weapon into the Sun, or could we really use nuclear
weapons to blow up the polar ice caps on Mars
(06:29):
and to make more atmosphere? Or what exactly happens when
you drop a nuclear weapon in X? Basically I get
these questions where X is anything? And so we're starting
a new series of podcasts titled what Happens if You
Explode a Nuke in Blank? And we're going to explore
everywhere you can imagine putting a nuclear weapon.
Speaker 2 (06:47):
So today, where are we exploding that nuke?
Speaker 1 (06:50):
Well, we're not putting that nuke in any sort of
biological locations. We're mostly going to focus on the physics locations.
And today on the podcast, we'll be answering the question
what happens if you explode a nuke in space?
Speaker 2 (07:08):
So we are definitely cordoning off any of the space whales,
any of the space jellyfish, any kind of free floating
space creatures that might be in the way of this nuke,
and presumably we're exploding it just in space space right
like where there's not too much around, just pure.
Speaker 1 (07:28):
Space, just pure space exactly. And I think this question
is super fascinating from a scientific point of view, because
mostly what we know and what we imagine about nuclear
weapons comes from the interaction of the nuclear blast with
the atmosphere or with the Earth, those shockwaves, and that
doesn't happen in space. So we'll go in detail through
exactly what does happen in a nuclear explosion and how
(07:50):
that propagates through space when it's not surrounded by a
cocoon of air. This also the really fascinating political and
sort of militaristic side of it, as humanity tries to
build a space based civilization. Space war is a big question,
and so like understanding what happens when you blow up
a nuke in space from a sort of political or
military strategic point of view is also really interesting and important.
Speaker 2 (08:14):
Could we go somewhere in the universe and not put
wars in there?
Speaker 1 (08:20):
I think only if we don't bring the humans right,
the wars come with the humans.
Speaker 2 (08:25):
I think only puppies should go to space so that
don't start any wars.
Speaker 1 (08:29):
But that's also a really fascinating question. You see in
a lot of science fiction novels human civilization spread out
through the galaxy, or humans and aliens spread out through
the galaxy able to access all these vast resources, and
yet still fighting right, still having wars, and I wonder
if that's really true. I often pose that question to
our science fiction author guests, like, what are these people
fighting about? There's essentially limitless resources. Like you want water,
(08:54):
go to Neptune, it's basically a planet of water. You
want gold, there's like enormous blobs gold out there. Platinum
like this asteroid's made of platinum. If you need something,
don't come kill us for it, just go get it.
If you want energy, like the Sun is out there
dumping out energy, it seems to me that once you
make it to space, I don't know why people would
(09:14):
still be having wars unless they're just fundamentally grumpy.
Speaker 2 (09:18):
That could be. I think that if you have resources
spread out relatively fairly, right, like you don't have a
space king that's hoarding all the Neptune water for himself,
that yeah, it would make sense that there would be
fewer wars because I think when people have a lot
of resources, they have a good quality of life, why
would they want to go to war? You know, what
(09:40):
would be the purpose for the everyday person to risk
it all for war? Again, if we have like space monarchies,
then yeah, there might be some wars.
Speaker 1 (09:48):
Yeah. Well, there are some really interesting science fiction explorations
of this, like the Culture series and other like post
scarcity novels where basically everybody has everything they ever want.
You just ask for something and you get it, and
they explore like what would life be like in that situation. Anyway,
back to the topic of today's podcast, we are not
yet there. We are not yet in outer space living
among the riches where everybody gets their own platinum throne. Instead,
(10:11):
we're still down here on Earth and wondering what would
happen if you blew up a nuclear weapon in space?
And so, as usual, I pulled our listeners to hear
what they thought might happen in this scenario. If you
would like to participate in this segment of the podcast
giving your informed or uninformed answers for us to hear,
please don't be shy write to me two questions at
(10:31):
Danielandjorge dot com. So think about it for a minute.
Do you know what would happen if we blew up
a nuclear bomb in space? Here's what our listeners had
to say, probably.
Speaker 3 (10:42):
Something very similar to what happens if you explode a
nuclear bomb not in space. A lot of energy is released.
Basically it's what the Sun is doing, so it's just
a bunch of energy pouring out into space.
Speaker 4 (10:53):
I think that exploding a nucleipon in space would have
very little effect. It would be a pretty clean explosion.
If there're at some radio active particles, but there's loads
of them flying around in space anyway, so essentially I
have no concerns.
Speaker 5 (11:07):
Go for it.
Speaker 6 (11:07):
So if I understand right how a nuke works, it
requires a chain reaction between the atoms of our atmosphere,
So in deep space without atmosphere, it will have no effects.
Speaker 7 (11:21):
You'd see a big, huge round flash, blinding flash of light,
and then you wouldn't hear anything, I guess because it's
the vacuum of space. And then as soon as all
the the fuel, the hydrogen was or uranium or plutonium
was gone, it should be done. And I don't think
(11:41):
it's any debris, because there's no like that start all
lighted up.
Speaker 8 (11:45):
Is this an atomic bomb or a hydrogen bomb? I
think either way. I think you just make a tiny
little sun for a second, and then that much would happen,
except for some more radiation in space.
Speaker 1 (11:55):
I assume it would just sort of do the same
thing it does here without a shock wave.
Speaker 9 (12:02):
I believe that unless it's something close or it is
something to you know, to a planet, or maybe close
to I don't know, like a nebula, maybe it will
you know, push away that. But other than that, maybe
the only thing in space that will happen, if you know,
if it's in the vacuum space, it will create maybe
a little bit of a gravitational waves maybe, I don't know.
Speaker 5 (12:24):
Well, you won't get a mushroom cloud, that's for sure,
because that only happens in the atmosphere. So when a
nuclear explosion happens, I believe that it releases basically lots
and lots of radiation in the form of photons and
the radioactive particles. So I imagine like a big bright
(12:45):
ball of light that will flash for a second and disappear.
Speaker 10 (12:50):
I would suppose that the nuclear bomb would still explode,
and having nothing for the explosion too press back against.
I would expect that the explosion would be equal in
all directions, and that the residual matter would fly out
in all directions equally.
Speaker 2 (13:11):
That's a lot of different answers, really interesting ideas. I
think the main thing people are thinking of, like it
in space, Right, you don't have atmosphere, you don't have air,
so you're not going to have the things that air
and atmosphere provides, like say a shock wave or sound.
Speaker 1 (13:30):
Yeah, it's basically like a little sun in space. Is
a great little argument. There was somebody who said something
about how it requires a chain reaction in the atmosphere,
so in space it'll have no effect, which I think
might have some misunderstanding of how a nuclear weapon works.
But on the whole, yeah, these are great answers.
Speaker 2 (13:47):
Well, how I think nuclear explosions work is you take
it at them and you get a little axe, very
sharp ax, and Y split it in half and that
releases a bunch of energy in floats.
Speaker 1 (14:00):
Tell me I'm wrong, You're wrong, although you could be wronger,
I mean there is some elevation that is correct. Essentially,
there's two ways to make a nuclear explosion. One is
fission and one is fusion. Fission is when you're cracking
a big, heavy atom open. So you have like uranium
or something which already is on the verge of breaking apart,
(14:23):
and you take a little ax, which in this case
is a neutron, and you shoot it at the uranium
and it breaks open and it makes more neutrons, and
those neutrons fly out and hit other uranium atoms, which
then crack open and release energy and more neutrons, and
then you get this chain reaction. And so if your
axe is basically a tiny little neutron axe, then maybe
(14:44):
that works. And actually isn't. Thor's hammer supposed to be
made out of neutron star so there's already a precedent
there for like tools made of neutrons.
Speaker 2 (14:51):
I knew Marvel was scientifically accurate in every way. That's
the fission part, where you have a bunch of un
stable large atoms being hacked apart by neutrons, and then
that interurn releases more neutrons than that hacks apart other
unstable atoms you've mentioned, though, there's a fusion one as well.
Speaker 1 (15:13):
Yeah, exactly, so that's fission. And the design of a
fission bomb is actually quite interesting, like the way you
get that to blow up, because if you just have
a bunch of uraniums sitting around, it's not going to
have a chain reaction unless it has enough density, like
you pack those things dense enough, then it's going to
blow up. But what you want in a bomb is
something that blows up when you want it to, not
just like when you build it right. You want something
(15:34):
like a fuse, and so you need a controlled explosion.
And so what they do is they have two pieces
of uranium, both of which do not have enough mass
to blow they are subcritical masses. And then what happens
in the bomb is you basically smash those two together,
combine them together to make a super critical mass when
they can actually trigger this runaway effect and cause the explosion.
(15:56):
And sometimes they even have like a little trigger like
a pellet of polonium or rialium or something to get
the first neutrons going. But you're right, that's all fission.
And so the first bomb that was ever developed and
was blown up in Alamagordo, New Mexico, not too far
from where I grew up, was a fission bomb. But
there's another much more powerful nuclear process that we now
have a handle on, and that is fusion. Fusion is
(16:18):
the opposite. Instead of breaking up a big heavy atom
to release energy, you're sticking two light atoms together to
make a heavier one. So two protons, for example, come
together to make helium. It's actually a little bit more complicated.
You end up with like multiple protons making multiple helium nuclei.
But squeezing light atoms together to make heavier ones releases energy,
(16:39):
just like chopping up heavier atoms to make lighter ones
releases energy.
Speaker 2 (16:43):
You mentioned that the fusion bombs are more powerful. Why
is that?
Speaker 1 (16:47):
Yeah, that's a great question. And people also wonder like
why is it that when you stick light materials together
to make heavier ones you release energy, and if you
break up heavier ones to make lighter ones, you release energy.
And the answer to both questions just comes from the
sort of energy structure of the nucleus. So when you
squeeze two protons together to make helium, the way those
(17:08):
two protons are bound together by the strong force contains
like a deep potential well, sort of like the Earth
falling into a gravitational well being captured by the sun.
Those two protons capture each other, so you need a
lot of energy to break that up. Like if you
want it to take helium and break it up into hydrogen,
you'd have to zap it with a really powerful laser.
You have to add energy to that. So the energy
(17:30):
that's released from fusion has to do with the difference
between the sort of energy structure of two protons that
are far apart from each other and two protons that
are bound together in two helium. And why that number
is big. It just has to do with the strong
force and like how powerful it is. On the other
side of the spectrum. When you're breaking up uranium into
lighter stuff. That's a really big, heavy nucleus and it's
(17:52):
a little unstable already because of electromagnetism, which is pushing
all those protons apart, and the strong force isn't as
powerful because those protons are further or apart from each other,
just because the nucleus is like physically getting so big
that the strong force isn't as powerful over those distances,
So it's a little bit easier to break that up,
and the strong force bonds aren't as powerful because the
distance is a little bit greater there. So it all
(18:14):
has to do with like the structure of the energy
levels of the nuclear formation, which you're super complicated.
Speaker 2 (18:19):
So when something heavy unstable atom, I thought that things
like uranium would sort of naturally decay because they are unstable.
Why don't they just spontaneously explode when they are decaying?
Speaker 1 (18:33):
You mean, why don't you get runaway nuclear reactions in nature?
Speaker 2 (18:37):
Exactly?
Speaker 1 (18:38):
Actually you can. The crucial thing is just having enough uranium.
Uranium is typically dilute out in the world. It's in
oxides and it's not very pure. But if you do
happen to have a fairly pure uranium deposit, like sitting underground,
it will undergo a natural fission reaction. And there's a
spot in Africa where they're very certain that a couple
of billion years ago there was enough urinea and it
(19:00):
started a natural fission reaction and like cooked the rock
and like heated up the whole thing. We did a
whole podcast episode about it a year or so ago. Uranium,
of course, is unstable, and so it decays, and the
kind of uranium you need is getting more and more rare,
so it's not a likely thing to happen again, like
the conditions for natural fission reactions on Earth without human
intervention are no longer likely to exist.
Speaker 2 (19:22):
Oh, that's really interesting. So back to the nuclear bombs,
Like what either for a fission bomb or a fusion bomb,
Like once you have set off that reaction, what happens
like on planet Earth exactly? Like what is the effect
the impact of a nuclear bomb?
Speaker 1 (19:41):
So all bombs essentially are just a rapid release of
energy some process which is exothermic, maybe chemical for like
dynamite or nuclear for fusion fission bombs, but just a
very rapid release of energy. And the crucial things to
understand is how that energy is carried. In the case
of nuclear weapons, it's not just different carriers of energy
relative to chemical weapons, but it's also just much more dramatic. Right,
(20:04):
there's like so much more energy released per gram of
fuel because it's much more efficient at extracting energy from
those bonds. Chemical bonds and dynamite don't have nearly as
much energy as the nuclear bonds that we're releasing in
nuclear weapons, So you get different energy carriers flying out
and you just get a lot more So the energy
(20:25):
comes out in terms of photons, So like infrared photons,
visible light photons, UV photons, all of those things. You
also get a bunch of particles. You get neutrons, you
get electrons, you get protons, you get gamma rays, you
get all sorts of crazy things shooting out from the explosion.
Speaker 2 (20:43):
When I've seen footage of test explosions of a nuclear
bomb on like an uninhabited house, it looks like this
huge wave of air almost just obliterating the house as
it passes through. What's causing that big shockwave a of air?
Is that just all these particles being released, this super
energy particles, or is there some kind of heat that's
(21:05):
also being released from the bomb.
Speaker 1 (21:07):
So when you detonate a nuclear weapon, you produce all
of this energy in various forms, and then you have
to ask, like, Okay, the shell of stuff around the
nuclear weapon, the air or the water or whatever, is
that transparent to these energy carriers? Will it absorb that
energy or will it just pass through? And in some
cases it's transparent, in some cases it's not. So when
it's not transparent, when it's opaque, when it's going to
(21:29):
absorb that energy, then all that energy is getting dumped
into the air. So, for example, a lot of those
photons are absorbed by the air. The infrared, for example,
very efficiently absorbed by the air around the nuclear bomb,
and that heats up the air. So the energy has
been transformed from lower energy photons into temperature of the air.
So now that air is super duper hot. You've superheated
(21:51):
that air and it expands and then that heats the
air around it. And so that's where the shockwave comes from,
from the dumping of that energy from the particle that
come out of the nuclear weapons into the air itself,
and then the air becomes part of the explosion.
Speaker 2 (22:06):
I see. And so you're saying, unless it's transparent, I
would assume that both air and water would absorb energy
from a nuke. So it doesn't seem like there'd be
anywhere on Earth where you wouldn't have an impact of
a nuclear explosion, right.
Speaker 1 (22:22):
That's right. And so the breakdown is something like around
fifty percent of the energy in the air or in
the water goes into forming this shock wave. Basically it
gets turned into sound. Right, Sound is just matter pressing
on other matters compression waves. So like half the energy
of the nuclear bomb is absorbed by the matter that
surrounds it and then expands that something like forty percent
(22:43):
of it are photons to which the atmosphere or the
water are mostly transparent, so visible light UV light. Right,
the atmosphere is transparent to visible light. That's why we
can see each other and we can see the sun
because the atmosphere doesn't tend to absorb photons in this
range that we can see. And that's of course no accident.
That's why we can see these photons. We're evolved in
(23:04):
a situation to see these very useful photons. So fifty
percent into shock waves, forty percent into basically photons to
which the atmosphere of the water is transparent, and then
like ten percent of the energy in things like neutrons
and electrons, like other particles flying out like tiny bullets
with high energy, which can also pass right through the atmosphere.
Speaker 2 (23:24):
So is it as hot as like having a little
sun in that area where the bomb went off? Like
how hot does that get?
Speaker 1 (23:34):
Yeah, it gets to millions of degrees Calvin, It's really
incredibly hot. It's a huge amount of energy And that
sounds really hot, and it is really hot, and it's
actually hotter than the surface of the Sun, which is
just a few thousand degrees Calvin, and that's why it
can release energy like much much higher wavelengths. To remember
that the temperature of an object controls the energy spectrum
(23:56):
that's released. The hotter it is, the higher the frequency,
the higher energy the radiation, and so that's why nuclear
weapons release a lot of energy in the UV where
we can't even see it because they are so dang hot.
Speaker 2 (24:09):
It is extremely bright as well, right, Like I think
that's something that everyone's kind of aware of, how incredibly
bright a nuclear explosion is, like you said, because the
light passes through the air and then we can see it.
Is it a white light or a yellow light? It'd
be probably a white light, right.
Speaker 1 (24:26):
It's basically broad spectrum, And so if you're watching a
nuclear explosion, you actually see sort of two flashes. You
see an initial flash of light because it's very very
bright and it's very broad spectrum and it looks very white.
But then light that's released later is actually captured by
the shockwave. So you have the first flash which comes
out very quickly. Then the shockwave comes out and photons
(24:46):
which sort of bump up against the inner side of
that shockwave. Don't see it as transparent because the shockwave
has made that air denser and so it's no longer transparent.
And so until that shockwave dissipates, it's basically blocking the
light from the nuclear wave. And when it does, then
you see a second flash. You know, it's producing light
the whole time, but it's like momentarily blocked. So you
(25:06):
see this characteristic double peak of gamma radiation when you
blow up a nuclear bomb here on Earth, at least
underwater or in the air.
Speaker 2 (25:14):
The other thing I think people think of when we
picture a nuclear explosion is that characteristic mushroom cloud. Why
does it have such a you know, specific shape, that
mushroom cloud shape. Is that just sort of basic physics
when it comes to an explosion that's large enough, or
is there something else going on.
Speaker 1 (25:34):
That's basic physics from a really large explosion. It's typical
for nuclear explosions because they are so powerful. You know,
you have this sudden formation of a really large volume
of lower density gases, and then you get a buoyant
massive gas which rises rapidly, giving you all this turbulence
and curling down around the edges. But it can come
(25:54):
from chemical explosions also if they are big enough.
Speaker 2 (25:57):
I see. Interesting. So when you have a nuclear explosion,
you have this huge amount of energy released. It superheats
the air, causes this shock wave, causes a massive amount
of energy to be released in heat in radiation, which
you know is a real sucker punch after the effects
of the bomb, right, Like, you have this radiation in
(26:18):
the area, and people can get radiation poisoning. But it dissipates,
it explodes, the energy dissipates, it reaks, whatever havoc it's
gonna reek and then it kind of it settles, the
dust cloud settles, the radiation settles, and then it's it's
a big explosion. And how long does it last? Typically
like the explosion part of a nuclear bomb.
Speaker 1 (26:41):
So the actual reaction is very quick, but you know,
the shockwave travels at the speed of sound, which is
being like a thousand feet per second, and so depending
on the strength of the bomb, it can be like
thirty seconds to a minute or so before that shock
wave dissipates. And you're right that the initial danger is
very very strong. You have the shockwave, you have the
radiation exposure. Sure, but then this is the lasting effects
(27:01):
of the fallout. Right, you have released a bunch of
radioactive material, not all of it has fused or fizzed.
And also that radiation creates more radioactive material. All these
high energy neutrons can slam into other stuff, turning them
into radioactive elements, and so the whole area is radioactor
for a while, and in the cloud they are radioactive
elements produced. When you have a fission reaction, we know
(27:23):
that it produces very dangerous toxic waste.
Speaker 5 (27:25):
Right.
Speaker 1 (27:26):
That's why nuclear reactors have such a tricky problem to
deal with. And a nuclear bomb that's not contained at all,
it's just blown up into the atmosphere, and so the
fallout can be very dangerous and it can drift, right,
you have wind for example, so it can drift over
hundreds of miles.
Speaker 2 (27:39):
Yeah, I mean that's one of the considerations that countries
have when they're thinking of using nukes. It's like, well,
if I use it on my neighbor, that might just
blow right back into my country, which I think is
in a way good, right, because you should think a
few times before you decide to ease a nuke. But
we should probably take a quick break practice our duck
(28:01):
and cover, and when we get back, talk about what
happens when you explode a nuke in space, not on Earth.
(28:22):
So I've practiced my duck and cover a few times,
which I'm sure would protect me really well if I
was in the heart of a nuclear explosion. My desk
is very sturdy. But we talked about what happens with
a nuclear explosion on Earth. Hopefully we'll never see one ourselves,
but what happens when you explode a nuke in space?
(28:44):
Because space is very different from our planet Earth. It's
missing a few things that we have that are nice
to have here on Earth that protects us in other life,
and so it seems like a nuclear bomb would react
differently in space.
Speaker 1 (29:01):
Yeah, it's really different, and in a fascinating way. The
actual core reaction, of course, is the same. When the
bomb goes off, it doesn't need the atmosphere or water
or anything around it in order to actually detonate. It's
not like a fire where you're using the oxygen from
the atmosphere to burn. It can go all by itself,
so it's happy to blow up in space or underwater
(29:22):
or underground or in the air. So the core reaction
is no different, and the things that it produces are
the same. So a nuclear bomb in space blowing up
produces the same spectrum of photon energies and neutron energies
and electrons, et cetera as the nuclear bomb blowing up
anywhere else. But of course the immediate surroundings of the
bomb are very different. And so now instead of having
(29:42):
some of that radiation immediately absorbed basically by a pillow
that was surrounded the bomb, a pillow of air or
water or dirt, now there's nothing there, so everything is transparent.
So all that radiation instead of getting dumped into some
blanket or some pillow, just flies out, so it all
stays as radiation. It just flies out like a mini sun,
(30:03):
as our listeners describe, filling nearby space with very dangerous radiation.
Speaker 2 (30:08):
So when I see things like in Star Trek or
Star Wars and they like fire some kind of missile
and then you see this like big explosion with like
a explodey cloud thing, if you're doing it just that
space right, like maybe I guess if you hit a spaceship,
you could get some debris that causes a bit of
(30:28):
a cloud. But if you're just firing out in space.
What exactly does an explosion look like when you're just
it's just happening in empty space?
Speaker 1 (30:36):
Yeah, great question. Those science fiction explosions use cues from
our intuition. On Earth, you know, where things are loud
and they are hot, But in space things would be different. Right.
There's no sound. I mean, there are some particles out
in space. It's not totally empty, so technically speaking, there
there is the ability to propagate sound waves, but there's
no sound, and there's also no flames, right, so what
(30:57):
you would see instead is a very bright flash of
light because all those particles are just flying out. There's
nothing burning there. And you say, maybe the ship itself
would explode if there's like fuel on board or whatever,
but there's no flame, there's no oxidization effects, no chemical
burning there. So essentially it's just a very bright pinprick
of light, extremely bright, like something you should definitely not
(31:19):
look at.
Speaker 2 (31:20):
So you don't get that double flash right like you
do with a nuke on Earth, because there's no shockwave
to absorb the light from and kind of prevent it
from reaching your eyes until the shockwave has moved on.
Speaker 1 (31:31):
Exactly, that shockwave is purely a product of a race
between the photons and the sound wave that's propagetting out.
But because there is no soundwave, there's no shockwave, there's
nothing there to absorb that radiation. All the radiation just
flies out, and so it looks quite different. And what
that means is that nuclear weapons are dangerous over much
greater distances in space because the radiation is not absorbed,
(31:54):
and so if a nuclear bomb blows up in space,
you can get significant radiation damage from it, even if
you're much further away.
Speaker 2 (32:01):
Say we exploded a nuke somewhere in our solar system,
would that radiation potentially hit.
Speaker 1 (32:09):
Earth, you still are protected by physics is one over
distance squared law. The same with the Sun is like
one hundred times dimmer if you're ten times further away,
or electric fields go down by a factor of four
if you're twice as far from the charge as all
these one over distance squared law in physics, which actually
not hard to understand. Like from a geometrical point of view,
(32:29):
you imagine, like particles flying out from a nuclear bomb
or photons flying out from the Sun, the same certain
number are released, and then as the radius grows, those
particles are now spread out over a larger and larger sphere,
and the area of that sphere goes like four pi
are squared. So as that sphere gets larger, the same
number of photons or dangerous particles are spread out over
(32:52):
a larger area. So for any given area of the
radiation drops like one over the distance squared. And so
if you're far away from this thing, you'll be safe. Now,
on Earth, you can be just a couple of miles, two, three,
four miles from an explosion and be mostly safe from
the radiation because so much of it is absorbed into
the atmosphere. But in space you've got to be like
(33:13):
forty fifty sixty miles to be as safe as you
would be on Earth, because essentially there's no protection. Right
on Earth, you're kind of protected from this nuclear bomb
by the atmosphere or by the ground, or by the water,
but in space there's nothing there to shield you.
Speaker 2 (33:28):
Right, So is this radiation constantly spreading out or does
it kind of stop dissipating after a while. Does it
keep dissipating forever until it just sort of has equalized somehow?
Speaker 1 (33:41):
Yeah, great question. Well, the initial explosion again is very brief.
The actual nuclear detonation doesn't last very long, and so
what you're thinking about is sort of like a pulse,
like all this radiation in a sphere that's traveling out
very very fast, in many cases actually at the speed
of light, and then getting dimmer and dimmer as it goes.
And so it's really just like a pulse that travels
through space, washing over things and damaging them.
Speaker 2 (34:03):
How long does that pulse last? Does it last like
seconds or hours or years?
Speaker 1 (34:09):
Well, the pulse itself would last for less than a second.
The actual explosion itself doesn't take very long, so it's
not like sitting there stewing, continuing to produce pulses of energy.
It's one very high intensity pulse over a short time.
But it's various kinds of radiation. Also. There's photons, very
high energies, and then there's neutrons, of course, and there's
also electrons. And the electrons can be particularly damaging and
(34:30):
also kind of fascinating because the electrons are traveling at
very very high speeds and they tend to radiate. So electrons,
when they move to a magnetic field or anything they
change direction, they radiate photons, and so that creates this
electromagnetic pulse. So all these electrons create this electromagnetic pulse
which can disrupt the flow of electricity or damage any
sort of electronics. And you see this in science fiction
(34:52):
all the time, right, that like electronics are blacked out
when there's a nuclear bomb, And that's really true. It
will create like pulses of energy in electronics.
Speaker 2 (35:00):
That's really interesting. So if you're a spaceship, right and
you're riding up and someone decides to blow up a
nuke in front of you, you're really screwed in many
ways because you've just got a huge dose of radiation
and then all of your electronics on your spaceship are
going to get messed up by that EMP pulse. Is
there anything else to look out for if you're on
(35:20):
that spaceship cruising and someone blows up a nuke, Miria, Well.
Speaker 1 (35:26):
If you're on that spaceship, I really hope you have
a special leadlined room to protect yourself, like we do
actually on the space station. Because the Sun, of course,
is a huge source of radiation, and solar storms can
generate EMPs and also other kinds of radiation which can
damage satellites and people, and so they have a special
room on the space station where the astronauts can go
(35:46):
like a panic room when there's going to be like
a high radiation solar weather event. And so I hope
your spaceship is outfitted with one of those, because if
somebody blows up a nuclear bomb, it's going to damage
your ship and also damage you if you're within tens
of miles.
Speaker 2 (35:59):
We know that for like when you explode a nuke
on Earth, long after the explosion, it's irradiated everything around,
and depending on how large the explosion is, the nature
of it, like with Chernobyl, the area in that exclusion
zone is still radioactive. Like it's still not necessarily a
safe place to be. It's not like you will immediately
(36:22):
get radiation poisoning and die if you step foot in
the exclusion zone, but you can get sick depending on
how long you're in there and how close you get
to the center where the explosion happened. But what happens,
like with this explosion in space, is there an area
like a sort of point in the middle that continues
(36:43):
to be sort of radioactive or does that without anything
to really absorb it, It just keeps moving until it
hits something that it can be absorbed by Yeah.
Speaker 1 (36:53):
Great question. And remember, of course Schernobyl was a nuclear
meltdown of a reactor, not an actual nuclear explosion, so
nothing blew up, so you still have a lot of
the fuel and all that stuff there in that same location.
The larger exclusion zone is because of the weather and
the air that pulled the smoke and the radioactive particles
further away, so there was never actually a nuclear explosion there.
And in space, you blow this bomb up, there's not
(37:15):
going to be really anything left in the location of
your detonation to poison people. Everything is going to fly
out because there's nothing stopping it, right, There's nothing holding
it in place at all, So you haven't like poured
radiation into a bunch of nearby dirt or water. Everything
is just going to flow away. So you could probably
come back in, you know, a month or so after
(37:36):
the nuclear bomb, and the space would be no different
from when you started. All of the dangerous elements would
be flying out from the source in lots of directions,
poisoning people or causing damage as they hit them, But
the actual location of the nuclear explosion in space isn't
going to be like affected in any way, have we.
Speaker 2 (37:53):
Ever thought to blow up a nuke? And I mean
I'm sure we've thought of it, but have we ever
actually done it before?
Speaker 1 (38:00):
Oh? Yes, we have actually blown up nuclear weapons in
lots of places. We've blown them up in more Unfortunately,
we've blown them up above ground, we've blown them up underground,
and we have actually done a nuclear explosion in space.
So we don't even have to wonder about what this
looks like. We know we have pictures.
Speaker 2 (38:18):
Well, that sounds terrifying. Let's take another quick break. I'm
gonna watch the little duck and cover turtle learn some
good lessons, and when we get back, I want you
to tell me about blowing up nukes and space, which
apparently we have already done. So we are back to
(38:48):
that little duck and cover turtle. He's got a turtle shell,
but he's also got a helmet redundant. Anyways, now we're
going to talk about how we actually have already blown
up a nuke in space. It terrifies me that we
may have pissed off some aliens and many generations from
now they'll finally reach us and give us a real scolding.
(39:10):
But Daniel, what happened? Why did we blow up space.
Speaker 1 (39:14):
So nuclear testing started in nineteen forty five with the
Manhattan Project. The US, of course the first country to
develop these things and to test them and then to
use them in war, where thousands of people were killed horribly.
And since then there's been about two thousand nuclear explosions
conducted by humans. And in the early days it was
free for all, there were no laws. People were blowing
(39:35):
stuff underground, above ground, et cetera. But we pretty rapidly
realized that blowing up stuff in our atmosphere was a
bad idea, creating radioactive particles and fallout. They could drift anywhere.
We blew up a bunch of islands, which is terrible,
destroying people's homes. And so that was in the fifties,
and things were of course very tense between the US
and the USSR. The US had stopped atmospheric testing, but
(39:57):
in the early sixties the USSR started atmospheric testing again,
which was sort of part of a larger political struggle
within the USSR to like stand up to the US.
We really should have like a Russian political expert on
to tell us about why they started that up again.
But in nineteen sixty two, the US wanted to know, like, well,
what happens if you blow up a nuke in space?
They were basically curious, and they didn't want to do
(40:19):
any more atmospheric testing, and so they tested a nuke
over the Pacific in July of nineteen sixty two.
Speaker 2 (40:26):
So I'm thinking, like, if we blow it up just
a little bit above our atmosphere, that's not going to
cut it. Like how far away did we go? Because
you know, it seems like if you're too close you
can still have an impact on the Earth that you're
not going to want.
Speaker 1 (40:43):
Yeah, exactly, if it's too far away, you won't be
able to see it because we don't have great instruments
in space. If it's too close, then it's basically in
your atmosphere, and said they chose an altitude of two
hundred and forty miles above the Earth's surface, and they
launched a one point four mega ton nuke from Johnston Island,
which is like fifteen hundred kilometers southwest of Hawaii. And
(41:05):
the idea was like, well, if something bad happens, does
have it happen over less populated areas, I guess, And
people imagine like, oh, that's far enough away from Hawaii
to not be a big deal, right, And they check
with a scientist and the sounds just like yeah, right,
no problem. Turns out those scientists were wrong. Oh boy, yep. Scientists,
especially physicists, can be wrong.
Speaker 2 (41:25):
Yeah, which is a big deal when you're talking about
a nuke and talking about people just trying to live
their lives. And then you're like, but we're curious to
see what this will do. Yikes.
Speaker 1 (41:37):
You can google this thing. It's called starfish prime and
just as we expect, it makes a spherical explosion. So
you don't get like a mushroom cloud that's a product
of blowing up in an atmosphere. You just get this
spherical explosion. It's not completely perfectly spherical, because the nuclear
bomb is not perfectly symmetric. There's like some small differences
in how the explosion happens based on exactly how the
(41:59):
fuel is ranged. But it's almost completely spherical.
Speaker 2 (42:03):
It kind of looks like a flower or like a
drawing of a sun where you kind of make the
outsides a little spiky, but yeah, it is pretty round,
and you've got like this bright white point in the middle,
and then you've got sort of a blue corona around it,
and then a larger white corona around the blue. What
is that sort of color difference. Why do you have
(42:24):
that like bright white light and then this blue and
then bright white light again on the outer edges.
Speaker 1 (42:30):
Yeah. I think it's similar to the effects we were
talking about in the atmosphere, that there is some debris
that comes out of the explosion, and then the radiation
that's emitted after that is partially absorbed by some of
that debris, some of those heavier ions that are created
by the explosion, So you get this multiple effect with
the products of the explosion then absorb things that are
later produced in the latter stages of the explosion. And
(42:53):
it was a pretty dramatic event on Earth.
Speaker 2 (42:55):
Yeah, I mean where people told this was going to happen.
Speaker 1 (42:58):
People were told it was going to happen, and even
the newspapers were aware, and they kind of advertised it.
There's a headline in the Honolulu Advertiser, which is a newspaper,
which says, in blast night maybe dazzling, good view likely,
And a bunch of hotels in Hawaii had like rooftop
parties for people to watch this nuclear explosion happen.
Speaker 2 (43:16):
I would be in a basement, but what would it
look like to someone on one of these rooftop parties.
Speaker 1 (43:24):
So you can't see the actual explosion the same way
because of the atmosphere, but there aren't these great pictures
that people took from Hawaii. And you see all this
air glow. You see all this red light because the
radiation has hit the atmosphere and it's excited a bunch
of oxygen atoms which then glow. So it's basically like
heated up the atmosphere which then glows in this red light.
Speaker 2 (43:45):
I mean that seems spectacular but also maybe kind of
apocalyptic looking. That would scare me.
Speaker 1 (43:52):
Yeah, And then after the actual explosion there's a massive
aurora scene for like thousands of kilometers. You know, the
Northern Lights. These are high energy particles hitting the atmosphere.
They're mostly funneled up to the Northern and Southern poles
because of the magnetic field. But when a huge number
of high energy photons hit the atmosphere, they make the
atmosphere glow and you don't just get red, you get
(44:13):
greens and blues depending on exactly what it is that
has been like zapped and energized and then re emitted.
And so whereas you don't normally see auroras in Honolulu,
they had this massive aurora which stretched for thousands of
kilometers over the Pacific.
Speaker 2 (44:28):
Well, maybe worth it to take a chance to accidentally
blow up a bunch of people, But you did mention
that the scientists had not quite calculated this right, So
were people actually in danger here? Like was there some
negative consequences to this?
Speaker 1 (44:46):
Well, it like blew out street lights in Hawaii?
Speaker 2 (44:48):
Oh wow, So this.
Speaker 1 (44:49):
Electromagnetic pulse that was created went much further than the
scientists thought. I think they didn't realize how much of
that is absorbed by the atmosphere when you blow this
thing up on Earth, or when you blow it up underwater.
And so the radiation effects of this bomb in space
were much broader than they had anticipated. And so, yeah,
there were effects on Hawaii. They destroyed a bunch of
satellites that were up in space. Back then, there weren't
(45:12):
that many satellites. This is the beginning of the space era,
so only like six satellites were destroyed. These days, you
blew up a nuclear weapon and that kind of location,
you destroyed dozens of satellites, billions of dollars of damage,
and people were able to see this thing for like
thousands of miles away. People on Fiji described the light
show as breathtaking.
Speaker 2 (45:31):
Wow. I mean, so you mentioned that the radiation spread
out much further than they had suspected. Did that negatively
impact Hawaiians? Did that hurt people on the island or
did it not actually have too much of a human impact.
Speaker 1 (45:45):
It doesn't have very much of a human impact because
fortunately we are under the atmosphere, which is a really
thick blanket to protect ourselves from a lot of this radiation.
And so really the only impact in Hawaii was the
dramatic light show and the pulse from the EMP, which
damaged some electrical devices and blew out street lights and
dumped a bunch of energy basically in any conductor that
(46:05):
can absorb electromagnetic energy for hundreds of kilometers, and so
satellights and street lights are basically the only real damage.
There may also be some very small amounts of radioactive material,
but distributed over such a large area that doubt has
really any impact on it, like human life.
Speaker 2 (46:21):
Well, it could have gone worse, it could have been.
Speaker 1 (46:25):
Wronger, and actually some scientists were wondering if this was
going to have a long lasting effect on other features
of nearby space. Remember that near the Earth there are
these huge bands of radiation. They're called the Van Allen Belts,
and they're basically just particles like whizzing around the Earth
that were discovered in the fifties whence we sent up
our first space missions. That as you leave the Earth
(46:47):
you pass through these bands of massive radiation. There's an
inner belt and there's an outer belt. They're not very
well understood, and at the time they were seen as
like an impediment to space travel, that if you go
up into space, you have to survive passage through these
basically radiation guns. And some scientists were wondering, if we
blow up a nuclear weapon in these radiation belts, maybe
it would like disturb them or dissipate them, though some
(47:09):
people were sort of hopeful that it would blow up
the radiation belts, which to me is kind of crazy.
It's like, before you even really understand these things and
their purpose and their benefits and their detriments, you want
to just like blow them up and see what happens
to life on Earth.
Speaker 2 (47:22):
Yeah, I mean, it's kind of looking forward and not
looking at the current situation right because you're thinking, like,
let's make space travel easier. But we have this functional
planet that we're pretty cozy on, so you might not
want to mess that up for some kind of future
space highway. I think that it is a lot of
(47:42):
decisions that we make we don't often think about, like,
but how will this impact the planet before we build
this space highway or regular highway? Did it impact these
radiation belts or did it not really have a permanent impact.
Speaker 1 (47:57):
I had basically no impact on the radiation belts, which
contain an enormous amount of energy which could not be
affected by one nuclear bomb. But this nuclear explosion did
have sort of shockwaves through the political climate on Earth.
Things cooled down a little bit, and in nineteen sixty
three they passed a partial Test Ban treaty which prohibited
all nuclear testing except for underground testing, which was seen
(48:19):
as safer because it really is very well contained. And
so for about thirty years, the US and Soviet Union
did a bunch of underground tests until they were prohibited
in nineteen ninety six. I still remember my dad traveling
to the Nevada test site to participate in some of
those tests. So the US was still testing nuclear weapons
(48:39):
into the nineties. We have not blown one up since then.
The last nuclear test from the US was in the nineties.
Speaker 2 (48:45):
It really feels like such a scary time though, during
the Cold War, when you're having all these tests going on,
you wonder about how many close calls we had in
terms of a test going wrong where it actually hurts people,
or a test that happens is misread by like say
that Russians are you know, by the US, and we think, well,
(49:06):
we're being attacked and that starts a whole cascade of nukes.
It feels like this wild West time where we were
just i mean, maybe not playing around with nukes, but
the fact we were doing so many of these tests,
and it feels like we just kind of escaped some
kind of horrible fate by the skin of our teeth.
Speaker 1 (49:26):
We certainly did. If you dig too deep into his history,
it's terrifying. There were times when like a flock of
seagulls were mistaken for the launch of a nuclear weapon.
Another time when like a training tape was accidentally loaded
into a computer which became convinced that the Russians were
attacking us. It's really terrifying how close we came to
all out nuclear war several times. And you know, the
(49:47):
US and the USSR haven't tested nuclear weapons since the nineties,
but you know, India and Pakistan detonated nuclear weapons in
the very late nineties, and then of course North Korea
has done tests fairly recently of nuclear weapons. So it's
not like we're out of the woods in terms of
nuclear weapons. Nope, yeah, exactly. Israel actually is the only
(50:08):
country we think has nuclear weapons but has never done
a nuclear test that we know of, that we know of.
Speaker 2 (50:14):
Yeah, I mean, it's interesting because at the start of
the Russian Ukraine War, I started following a bunch of
nuclear proliferation experts and sort of people who understood the politics,
who understood the science of nukes, because I was terrified,
and I'm not gonna say I got less terrified after
(50:36):
hearing what the experts had to say. I think the
knowledge of exactly the kind of circumstances that we were
in and stuff was helpful. Like, even though the Cold
War is over, the fact that there are so many
nukes out there, it's terrifying, so we should probably send
them all the space blaw them all up put them
in space.
Speaker 1 (50:55):
I guess if I had to choose where to blow
up nuclear bombs, I probably choose to blow them up
in space, over the atmosphere or anywhere else on Earth.
But it is really interesting to understand what happens to
a nuclear bomb when you blow it up in space.
It turns out to be quite different from what happens
in our atmosphere. It doesn't dump that energy and create
a shock wave. It's basically like a little miniature sun,
(51:16):
and so there is no shockwave to hurt you, but
that radiation will travel much much further and damage things
that are much further away, especially electronics. So let's hope
that we don't end up in a nuclear space war
anytime soon.
Speaker 2 (51:29):
And if you're flying your spaceship and you want to
fire some nukes, wear sunglasses.
Speaker 1 (51:35):
And be careful microwaving your soup, and put a lid
on your blender when you make that strawberry smoothie.
Speaker 2 (51:39):
All of this is practical advice.
Speaker 1 (51:42):
Thanks Katie very much for joining us on this exclusive episode,
Thanks for having me, and thanks to all of our listeners.
Tune in next time. Thanks for listening, and remember that
Daniel and Jorge Explain the Universe is a production of iHeartRadio.
(52:03):
For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to your favorite shows.
Hey, Katie, what's the biggest thing that you've ever seen
blow up?
Speaker 2 (00:12):
Technically soup that I microwaved too high, But I've always
wanted to see one of those building demolitions.
Speaker 1 (00:20):
Oh, that does sound fun. I'd love to see you
blow up soup or watch a building get exploded. I
wonder if they sell tickets to those events.
Speaker 2 (00:27):
I hope they go on tour, and I hope they
come to my city. What about you, what is the
biggest explosion that you have seen?
Speaker 1 (00:35):
Well, there was the time that I made a strawberry
smoothie without putting a lid on the blender and I'm
still cleaning up strawberry in the kitchen years later. But
I did once see a shoe store explode when an
air and firework hitted on New Year's Eve. It was crazy.
You could feel the heat from blocks away.
Speaker 2 (00:53):
That's crazy, that's amazing. I'm sure you were going to
say something more dramatic, though.
Speaker 1 (00:59):
More dramatic than a flaming shoes door, but.
Speaker 2 (01:02):
I thought so you grew up in Los Alamos, Like,
isn't that the home of the atomic bomb?
Speaker 1 (01:08):
It is, but we don't just like set them off
on holidays.
Speaker 2 (01:12):
That seems like a shame.
Speaker 1 (01:14):
I guess you could say we've kind of blown it.
Speaker 2 (01:18):
You didn't blew it, and that's the problem.
Speaker 1 (01:35):
Hi. I'm Daniel. I'm a particle physicist and a professor
at UC Irvine, and I hope to never be near
a nuclear explosion.
Speaker 2 (01:43):
I am Katie Golden. I host the podcast Creature Feature,
and I hope there's never a nuclear explosion anywhere ever, space, Earth,
what have you? It seems like a bad sign of
things to come.
Speaker 1 (01:59):
Are you saying that nukes can never be used for good?
You're not aware of the Peacetime nuclear weapons program or
the design of the Orion spaceship, which literally uses nuclear
weapons blowing up behind it in order to propel it forward.
Speaker 2 (02:13):
I mean, if you're basically gonna do big space farts
with nukes to make your spaceship go, I'll make an exception.
Speaker 1 (02:22):
All right. We have already broken down your barriers here
and so welcome to the podcast. Daniel and Jorge Explain
the Universe, a production of iHeartRadio in which we dive
deep into everything that happens in the universe, how it
all works, how it all began, how it all might end,
and how humans might bring about their own demise.
Speaker 2 (02:42):
I'm a big fan of life on Earth. I love
all the animals on Earth, love all the plants, and
the humans, most of them, ninety nine percent of humans.
And you know, I have a lot of nuclear anxiety
when it comes to the planet Earth, because I don't
want one going off and you know, destroying a bunch
(03:04):
of stuff, radiating things, maybe causing a new ice age
with the clouds of debris. But I guess if it's
blown up in space, I'm a little less worried.
Speaker 1 (03:16):
Well, this to me is a really interesting area because
it brings together the sort of fascinating progress we make
in physics as we start to understand the way the
universe works, what the forces are that underlie everything, how
they weave themselves together to make our reality. Understanding that
also gives us new power, the power to use that
knowledge to develop new technologies, which of course can be
(03:38):
good in peace time, like transistors and iPhones, but also
can be used to make weapons of mass destruction that
are pointed at civilian populations for political gain. And so,
while we like on this podcast to think about the
physics side of it, the scientific edge of knowledge, how
we can always push that forward, and we generally think
about that knowledge as purely good as sausfying our curiosity
(04:01):
is scratching our itch that wonders about how the universe works.
It's not possible to really live in a bubble and
pretend that that knowledge can't be used in all sorts
of ways that the original scientists who worked on it
aren't in control of. Personally, I did grow up in
Los Alamo's home in the Manhattan Project in Los Almos
National Laboratory, where weapons projects are ongoing to this day,
(04:23):
and both of my parents worked at the lab and
worked on weapons related projects. What exactly they did, I
don't know. I didn't know. I will never know, because
I don't have particular rants to know such secrets. But
such power over the universe comes with real responsibility.
Speaker 2 (04:38):
Yeah, I think I remember that a lot of these
scientists who worked on the Manhattan Project became very anti
nuclear proliferation. You know. It's it's something that I think
people who really understand the devastating power of nukes also
are very much opposed to uncontrolled proliferation of dukes. I
(05:00):
don't think it's something where scientists are There's a bunch
of mad scientists who really just want to blow up
the planet. I think most of the scientists who really
understand this stuff are also probably pretty anxious and would
like a world with fewer nukes.
Speaker 1 (05:15):
Yeah. Absolutely, I do know that my mother worked on
nuclear non proliferation programs, ways that you can detect nuclear
fuel and nuclear explosions, et cetera. But my father definitely
worked on the weapons side of it. And I asked
him once, not, of course, like tell me some nuclear secrets,
but how do you feel about working on the design
of huge weapons that are in the end pointed at
(05:36):
civilian populations. And you know, back in the eighties when
he started that job, it was a different era. We
were still in the Cold War and developing our nuclear capabilities.
Sort of felt patriotic. Back then, it felt like, Hey,
you're contributing to your country, you're protecting us, you're defending us.
I'm not saying that it's morally crisp and clean. I
certainly chose to do particle physics because it has no
(05:58):
weapons applications, and nobody's ever use my research to kill anybody.
Speaker 2 (06:02):
Not yet, they haven't yet. Give me a pen and
a piece of paper, I'll come up with something that's.
Speaker 1 (06:09):
Right, The Higgs Boson bomb by Katie goldd Well. Nuclear
weapons are very powerful and very dangerous, and they have
also captured the public imagination and I get a lot
of interest in our podcast email box about nuclear weapons.
People wonder what would happen if you dropped the nuclear
weapon into the Sun, or could we really use nuclear
weapons to blow up the polar ice caps on Mars
(06:29):
and to make more atmosphere? Or what exactly happens when
you drop a nuclear weapon in X? Basically I get
these questions where X is anything? And so we're starting
a new series of podcasts titled what Happens if You
Explode a Nuke in Blank? And we're going to explore
everywhere you can imagine putting a nuclear weapon.
Speaker 2 (06:47):
So today, where are we exploding that nuke?
Speaker 1 (06:50):
Well, we're not putting that nuke in any sort of
biological locations. We're mostly going to focus on the physics locations.
And today on the podcast, we'll be answering the question
what happens if you explode a nuke in space?
Speaker 2 (07:08):
So we are definitely cordoning off any of the space whales,
any of the space jellyfish, any kind of free floating
space creatures that might be in the way of this nuke,
and presumably we're exploding it just in space space right
like where there's not too much around, just pure.
Speaker 1 (07:28):
Space, just pure space exactly. And I think this question
is super fascinating from a scientific point of view, because
mostly what we know and what we imagine about nuclear
weapons comes from the interaction of the nuclear blast with
the atmosphere or with the Earth, those shockwaves, and that
doesn't happen in space. So we'll go in detail through
exactly what does happen in a nuclear explosion and how
(07:50):
that propagates through space when it's not surrounded by a
cocoon of air. This also the really fascinating political and
sort of militaristic side of it, as humanity tries to
build a space based civilization. Space war is a big question,
and so like understanding what happens when you blow up
a nuke in space from a sort of political or
military strategic point of view is also really interesting and important.
Speaker 2 (08:14):
Could we go somewhere in the universe and not put
wars in there?
Speaker 1 (08:20):
I think only if we don't bring the humans right,
the wars come with the humans.
Speaker 2 (08:25):
I think only puppies should go to space so that
don't start any wars.
Speaker 1 (08:29):
But that's also a really fascinating question. You see in
a lot of science fiction novels human civilization spread out
through the galaxy, or humans and aliens spread out through
the galaxy able to access all these vast resources, and
yet still fighting right, still having wars, and I wonder
if that's really true. I often pose that question to
our science fiction author guests, like, what are these people
fighting about? There's essentially limitless resources. Like you want water,
(08:54):
go to Neptune, it's basically a planet of water. You
want gold, there's like enormous blobs gold out there. Platinum
like this asteroid's made of platinum. If you need something,
don't come kill us for it, just go get it.
If you want energy, like the Sun is out there
dumping out energy, it seems to me that once you
make it to space, I don't know why people would
(09:14):
still be having wars unless they're just fundamentally grumpy.
Speaker 2 (09:18):
That could be. I think that if you have resources
spread out relatively fairly, right, like you don't have a
space king that's hoarding all the Neptune water for himself,
that yeah, it would make sense that there would be
fewer wars because I think when people have a lot
of resources, they have a good quality of life, why
would they want to go to war? You know, what
(09:40):
would be the purpose for the everyday person to risk
it all for war? Again, if we have like space monarchies,
then yeah, there might be some wars.
Speaker 1 (09:48):
Yeah. Well, there are some really interesting science fiction explorations
of this, like the Culture series and other like post
scarcity novels where basically everybody has everything they ever want.
You just ask for something and you get it, and
they explore like what would life be like in that situation. Anyway,
back to the topic of today's podcast, we are not
yet there. We are not yet in outer space living
among the riches where everybody gets their own platinum throne. Instead,
(10:11):
we're still down here on Earth and wondering what would
happen if you blew up a nuclear weapon in space?
And so, as usual, I pulled our listeners to hear
what they thought might happen in this scenario. If you
would like to participate in this segment of the podcast
giving your informed or uninformed answers for us to hear,
please don't be shy write to me two questions at
(10:31):
Danielandjorge dot com. So think about it for a minute.
Do you know what would happen if we blew up
a nuclear bomb in space? Here's what our listeners had
to say, probably.
Speaker 3 (10:42):
Something very similar to what happens if you explode a
nuclear bomb not in space. A lot of energy is released.
Basically it's what the Sun is doing, so it's just
a bunch of energy pouring out into space.
Speaker 4 (10:53):
I think that exploding a nucleipon in space would have
very little effect. It would be a pretty clean explosion.
If there're at some radio active particles, but there's loads
of them flying around in space anyway, so essentially I
have no concerns.
Speaker 5 (11:07):
Go for it.
Speaker 6 (11:07):
So if I understand right how a nuke works, it
requires a chain reaction between the atoms of our atmosphere,
So in deep space without atmosphere, it will have no effects.
Speaker 7 (11:21):
You'd see a big, huge round flash, blinding flash of light,
and then you wouldn't hear anything, I guess because it's
the vacuum of space. And then as soon as all
the the fuel, the hydrogen was or uranium or plutonium
was gone, it should be done. And I don't think
(11:41):
it's any debris, because there's no like that start all
lighted up.
Speaker 8 (11:45):
Is this an atomic bomb or a hydrogen bomb? I
think either way. I think you just make a tiny
little sun for a second, and then that much would happen,
except for some more radiation in space.
Speaker 1 (11:55):
I assume it would just sort of do the same
thing it does here without a shock wave.
Speaker 9 (12:02):
I believe that unless it's something close or it is
something to you know, to a planet, or maybe close
to I don't know, like a nebula, maybe it will
you know, push away that. But other than that, maybe
the only thing in space that will happen, if you know,
if it's in the vacuum space, it will create maybe
a little bit of a gravitational waves maybe, I don't know.
Speaker 5 (12:24):
Well, you won't get a mushroom cloud, that's for sure,
because that only happens in the atmosphere. So when a
nuclear explosion happens, I believe that it releases basically lots
and lots of radiation in the form of photons and
the radioactive particles. So I imagine like a big bright
(12:45):
ball of light that will flash for a second and disappear.
Speaker 10 (12:50):
I would suppose that the nuclear bomb would still explode,
and having nothing for the explosion too press back against.
I would expect that the explosion would be equal in
all directions, and that the residual matter would fly out
in all directions equally.
Speaker 2 (13:11):
That's a lot of different answers, really interesting ideas. I
think the main thing people are thinking of, like it
in space, Right, you don't have atmosphere, you don't have air,
so you're not going to have the things that air
and atmosphere provides, like say a shock wave or sound.
Speaker 1 (13:30):
Yeah, it's basically like a little sun in space. Is
a great little argument. There was somebody who said something
about how it requires a chain reaction in the atmosphere,
so in space it'll have no effect, which I think
might have some misunderstanding of how a nuclear weapon works.
But on the whole, yeah, these are great answers.
Speaker 2 (13:47):
Well, how I think nuclear explosions work is you take
it at them and you get a little axe, very
sharp ax, and Y split it in half and that
releases a bunch of energy in floats.
Speaker 1 (14:00):
Tell me I'm wrong, You're wrong, although you could be wronger,
I mean there is some elevation that is correct. Essentially,
there's two ways to make a nuclear explosion. One is
fission and one is fusion. Fission is when you're cracking
a big, heavy atom open. So you have like uranium
or something which already is on the verge of breaking apart,
(14:23):
and you take a little ax, which in this case
is a neutron, and you shoot it at the uranium
and it breaks open and it makes more neutrons, and
those neutrons fly out and hit other uranium atoms, which
then crack open and release energy and more neutrons, and
then you get this chain reaction. And so if your
axe is basically a tiny little neutron axe, then maybe
(14:44):
that works. And actually isn't. Thor's hammer supposed to be
made out of neutron star so there's already a precedent
there for like tools made of neutrons.
Speaker 2 (14:51):
I knew Marvel was scientifically accurate in every way. That's
the fission part, where you have a bunch of un
stable large atoms being hacked apart by neutrons, and then
that interurn releases more neutrons than that hacks apart other
unstable atoms you've mentioned, though, there's a fusion one as well.
Speaker 1 (15:13):
Yeah, exactly, so that's fission. And the design of a
fission bomb is actually quite interesting, like the way you
get that to blow up, because if you just have
a bunch of uraniums sitting around, it's not going to
have a chain reaction unless it has enough density, like
you pack those things dense enough, then it's going to
blow up. But what you want in a bomb is
something that blows up when you want it to, not
just like when you build it right. You want something
(15:34):
like a fuse, and so you need a controlled explosion.
And so what they do is they have two pieces
of uranium, both of which do not have enough mass
to blow they are subcritical masses. And then what happens
in the bomb is you basically smash those two together,
combine them together to make a super critical mass when
they can actually trigger this runaway effect and cause the explosion.
(15:56):
And sometimes they even have like a little trigger like
a pellet of polonium or rialium or something to get
the first neutrons going. But you're right, that's all fission.
And so the first bomb that was ever developed and
was blown up in Alamagordo, New Mexico, not too far
from where I grew up, was a fission bomb. But
there's another much more powerful nuclear process that we now
have a handle on, and that is fusion. Fusion is
(16:18):
the opposite. Instead of breaking up a big heavy atom
to release energy, you're sticking two light atoms together to
make a heavier one. So two protons, for example, come
together to make helium. It's actually a little bit more complicated.
You end up with like multiple protons making multiple helium nuclei.
But squeezing light atoms together to make heavier ones releases energy,
(16:39):
just like chopping up heavier atoms to make lighter ones
releases energy.
Speaker 2 (16:43):
You mentioned that the fusion bombs are more powerful. Why
is that?
Speaker 1 (16:47):
Yeah, that's a great question. And people also wonder like
why is it that when you stick light materials together
to make heavier ones you release energy, and if you
break up heavier ones to make lighter ones, you release energy.
And the answer to both questions just comes from the
sort of energy structure of the nucleus. So when you
squeeze two protons together to make helium, the way those
(17:08):
two protons are bound together by the strong force contains
like a deep potential well, sort of like the Earth
falling into a gravitational well being captured by the sun.
Those two protons capture each other, so you need a
lot of energy to break that up. Like if you
want it to take helium and break it up into hydrogen,
you'd have to zap it with a really powerful laser.
You have to add energy to that. So the energy
(17:30):
that's released from fusion has to do with the difference
between the sort of energy structure of two protons that
are far apart from each other and two protons that
are bound together in two helium. And why that number
is big. It just has to do with the strong
force and like how powerful it is. On the other
side of the spectrum. When you're breaking up uranium into
lighter stuff. That's a really big, heavy nucleus and it's
(17:52):
a little unstable already because of electromagnetism, which is pushing
all those protons apart, and the strong force isn't as
powerful because those protons are further or apart from each other,
just because the nucleus is like physically getting so big
that the strong force isn't as powerful over those distances,
So it's a little bit easier to break that up,
and the strong force bonds aren't as powerful because the
distance is a little bit greater there. So it all
(18:14):
has to do with like the structure of the energy
levels of the nuclear formation, which you're super complicated.
Speaker 2 (18:19):
So when something heavy unstable atom, I thought that things
like uranium would sort of naturally decay because they are unstable.
Why don't they just spontaneously explode when they are decaying?
Speaker 1 (18:33):
You mean, why don't you get runaway nuclear reactions in nature?
Speaker 2 (18:37):
Exactly?
Speaker 1 (18:38):
Actually you can. The crucial thing is just having enough uranium.
Uranium is typically dilute out in the world. It's in
oxides and it's not very pure. But if you do
happen to have a fairly pure uranium deposit, like sitting underground,
it will undergo a natural fission reaction. And there's a
spot in Africa where they're very certain that a couple
of billion years ago there was enough urinea and it
(19:00):
started a natural fission reaction and like cooked the rock
and like heated up the whole thing. We did a
whole podcast episode about it a year or so ago. Uranium,
of course, is unstable, and so it decays, and the
kind of uranium you need is getting more and more rare,
so it's not a likely thing to happen again, like
the conditions for natural fission reactions on Earth without human
intervention are no longer likely to exist.
Speaker 2 (19:22):
Oh, that's really interesting. So back to the nuclear bombs,
Like what either for a fission bomb or a fusion bomb,
Like once you have set off that reaction, what happens
like on planet Earth exactly? Like what is the effect
the impact of a nuclear bomb?
Speaker 1 (19:41):
So all bombs essentially are just a rapid release of
energy some process which is exothermic, maybe chemical for like
dynamite or nuclear for fusion fission bombs, but just a
very rapid release of energy. And the crucial things to
understand is how that energy is carried. In the case
of nuclear weapons, it's not just different carriers of energy
relative to chemical weapons, but it's also just much more dramatic. Right,
(20:04):
there's like so much more energy released per gram of
fuel because it's much more efficient at extracting energy from
those bonds. Chemical bonds and dynamite don't have nearly as
much energy as the nuclear bonds that we're releasing in
nuclear weapons, So you get different energy carriers flying out
and you just get a lot more So the energy
(20:25):
comes out in terms of photons, So like infrared photons,
visible light photons, UV photons, all of those things. You
also get a bunch of particles. You get neutrons, you
get electrons, you get protons, you get gamma rays, you
get all sorts of crazy things shooting out from the explosion.
Speaker 2 (20:43):
When I've seen footage of test explosions of a nuclear
bomb on like an uninhabited house, it looks like this
huge wave of air almost just obliterating the house as
it passes through. What's causing that big shockwave a of air?
Is that just all these particles being released, this super
energy particles, or is there some kind of heat that's
(21:05):
also being released from the bomb.
Speaker 1 (21:07):
So when you detonate a nuclear weapon, you produce all
of this energy in various forms, and then you have
to ask, like, Okay, the shell of stuff around the
nuclear weapon, the air or the water or whatever, is
that transparent to these energy carriers? Will it absorb that
energy or will it just pass through? And in some
cases it's transparent, in some cases it's not. So when
it's not transparent, when it's opaque, when it's going to
(21:29):
absorb that energy, then all that energy is getting dumped
into the air. So, for example, a lot of those
photons are absorbed by the air. The infrared, for example,
very efficiently absorbed by the air around the nuclear bomb,
and that heats up the air. So the energy has
been transformed from lower energy photons into temperature of the air.
So now that air is super duper hot. You've superheated
(21:51):
that air and it expands and then that heats the
air around it. And so that's where the shockwave comes from,
from the dumping of that energy from the particle that
come out of the nuclear weapons into the air itself,
and then the air becomes part of the explosion.
Speaker 2 (22:06):
I see. And so you're saying, unless it's transparent, I
would assume that both air and water would absorb energy
from a nuke. So it doesn't seem like there'd be
anywhere on Earth where you wouldn't have an impact of
a nuclear explosion, right.
Speaker 1 (22:22):
That's right. And so the breakdown is something like around
fifty percent of the energy in the air or in
the water goes into forming this shock wave. Basically it
gets turned into sound. Right, Sound is just matter pressing
on other matters compression waves. So like half the energy
of the nuclear bomb is absorbed by the matter that
surrounds it and then expands that something like forty percent
(22:43):
of it are photons to which the atmosphere or the
water are mostly transparent, so visible light UV light. Right,
the atmosphere is transparent to visible light. That's why we
can see each other and we can see the sun
because the atmosphere doesn't tend to absorb photons in this
range that we can see. And that's of course no accident.
That's why we can see these photons. We're evolved in
(23:04):
a situation to see these very useful photons. So fifty
percent into shock waves, forty percent into basically photons to
which the atmosphere of the water is transparent, and then
like ten percent of the energy in things like neutrons
and electrons, like other particles flying out like tiny bullets
with high energy, which can also pass right through the atmosphere.
Speaker 2 (23:24):
So is it as hot as like having a little
sun in that area where the bomb went off? Like
how hot does that get?
Speaker 1 (23:34):
Yeah, it gets to millions of degrees Calvin, It's really
incredibly hot. It's a huge amount of energy And that
sounds really hot, and it is really hot, and it's
actually hotter than the surface of the Sun, which is
just a few thousand degrees Calvin, and that's why it
can release energy like much much higher wavelengths. To remember
that the temperature of an object controls the energy spectrum
(23:56):
that's released. The hotter it is, the higher the frequency,
the higher energy the radiation, and so that's why nuclear
weapons release a lot of energy in the UV where
we can't even see it because they are so dang hot.
Speaker 2 (24:09):
It is extremely bright as well, right, Like I think
that's something that everyone's kind of aware of, how incredibly
bright a nuclear explosion is, like you said, because the
light passes through the air and then we can see it.
Is it a white light or a yellow light? It'd
be probably a white light, right.
Speaker 1 (24:26):
It's basically broad spectrum, And so if you're watching a
nuclear explosion, you actually see sort of two flashes. You
see an initial flash of light because it's very very
bright and it's very broad spectrum and it looks very white.
But then light that's released later is actually captured by
the shockwave. So you have the first flash which comes
out very quickly. Then the shockwave comes out and photons
(24:46):
which sort of bump up against the inner side of
that shockwave. Don't see it as transparent because the shockwave
has made that air denser and so it's no longer transparent.
And so until that shockwave dissipates, it's basically blocking the
light from the nuclear wave. And when it does, then
you see a second flash. You know, it's producing light
the whole time, but it's like momentarily blocked. So you
(25:06):
see this characteristic double peak of gamma radiation when you
blow up a nuclear bomb here on Earth, at least
underwater or in the air.
Speaker 2 (25:14):
The other thing I think people think of when we
picture a nuclear explosion is that characteristic mushroom cloud. Why
does it have such a you know, specific shape, that
mushroom cloud shape. Is that just sort of basic physics
when it comes to an explosion that's large enough, or
is there something else going on.
Speaker 1 (25:34):
That's basic physics from a really large explosion. It's typical
for nuclear explosions because they are so powerful. You know,
you have this sudden formation of a really large volume
of lower density gases, and then you get a buoyant
massive gas which rises rapidly, giving you all this turbulence
and curling down around the edges. But it can come
(25:54):
from chemical explosions also if they are big enough.
Speaker 2 (25:57):
I see. Interesting. So when you have a nuclear explosion,
you have this huge amount of energy released. It superheats
the air, causes this shock wave, causes a massive amount
of energy to be released in heat in radiation, which
you know is a real sucker punch after the effects
of the bomb, right, Like, you have this radiation in
(26:18):
the area, and people can get radiation poisoning. But it dissipates,
it explodes, the energy dissipates, it reaks, whatever havoc it's
gonna reek and then it kind of it settles, the
dust cloud settles, the radiation settles, and then it's it's
a big explosion. And how long does it last? Typically
like the explosion part of a nuclear bomb.
Speaker 1 (26:41):
So the actual reaction is very quick, but you know,
the shockwave travels at the speed of sound, which is
being like a thousand feet per second, and so depending
on the strength of the bomb, it can be like
thirty seconds to a minute or so before that shock
wave dissipates. And you're right that the initial danger is
very very strong. You have the shockwave, you have the
radiation exposure. Sure, but then this is the lasting effects
(27:01):
of the fallout. Right, you have released a bunch of
radioactive material, not all of it has fused or fizzed.
And also that radiation creates more radioactive material. All these
high energy neutrons can slam into other stuff, turning them
into radioactive elements, and so the whole area is radioactor
for a while, and in the cloud they are radioactive
elements produced. When you have a fission reaction, we know
(27:23):
that it produces very dangerous toxic waste.
Speaker 5 (27:25):
Right.
Speaker 1 (27:26):
That's why nuclear reactors have such a tricky problem to
deal with. And a nuclear bomb that's not contained at all,
it's just blown up into the atmosphere, and so the
fallout can be very dangerous and it can drift, right,
you have wind for example, so it can drift over
hundreds of miles.
Speaker 2 (27:39):
Yeah, I mean that's one of the considerations that countries
have when they're thinking of using nukes. It's like, well,
if I use it on my neighbor, that might just
blow right back into my country, which I think is
in a way good, right, because you should think a
few times before you decide to ease a nuke. But
we should probably take a quick break practice our duck
(28:01):
and cover, and when we get back, talk about what
happens when you explode a nuke in space, not on Earth.
(28:22):
So I've practiced my duck and cover a few times,
which I'm sure would protect me really well if I
was in the heart of a nuclear explosion. My desk
is very sturdy. But we talked about what happens with
a nuclear explosion on Earth. Hopefully we'll never see one ourselves,
but what happens when you explode a nuke in space?
(28:44):
Because space is very different from our planet Earth. It's
missing a few things that we have that are nice
to have here on Earth that protects us in other life,
and so it seems like a nuclear bomb would react
differently in space.
Speaker 1 (29:01):
Yeah, it's really different, and in a fascinating way. The
actual core reaction, of course, is the same. When the
bomb goes off, it doesn't need the atmosphere or water
or anything around it in order to actually detonate. It's
not like a fire where you're using the oxygen from
the atmosphere to burn. It can go all by itself,
so it's happy to blow up in space or underwater
(29:22):
or underground or in the air. So the core reaction
is no different, and the things that it produces are
the same. So a nuclear bomb in space blowing up
produces the same spectrum of photon energies and neutron energies
and electrons, et cetera as the nuclear bomb blowing up
anywhere else. But of course the immediate surroundings of the
bomb are very different. And so now instead of having
(29:42):
some of that radiation immediately absorbed basically by a pillow
that was surrounded the bomb, a pillow of air or
water or dirt, now there's nothing there, so everything is transparent.
So all that radiation instead of getting dumped into some
blanket or some pillow, just flies out, so it all
stays as radiation. It just flies out like a mini sun,
(30:03):
as our listeners describe, filling nearby space with very dangerous radiation.
Speaker 2 (30:08):
So when I see things like in Star Trek or
Star Wars and they like fire some kind of missile
and then you see this like big explosion with like
a explodey cloud thing, if you're doing it just that
space right, like maybe I guess if you hit a spaceship,
you could get some debris that causes a bit of
(30:28):
a cloud. But if you're just firing out in space.
What exactly does an explosion look like when you're just
it's just happening in empty space?
Speaker 1 (30:36):
Yeah, great question. Those science fiction explosions use cues from
our intuition. On Earth, you know, where things are loud
and they are hot, But in space things would be different. Right.
There's no sound. I mean, there are some particles out
in space. It's not totally empty, so technically speaking, there
there is the ability to propagate sound waves, but there's
no sound, and there's also no flames, right, so what
(30:57):
you would see instead is a very bright flash of
light because all those particles are just flying out. There's
nothing burning there. And you say, maybe the ship itself
would explode if there's like fuel on board or whatever,
but there's no flame, there's no oxidization effects, no chemical
burning there. So essentially it's just a very bright pinprick
of light, extremely bright, like something you should definitely not
(31:19):
look at.
Speaker 2 (31:20):
So you don't get that double flash right like you
do with a nuke on Earth, because there's no shockwave
to absorb the light from and kind of prevent it
from reaching your eyes until the shockwave has moved on.
Speaker 1 (31:31):
Exactly, that shockwave is purely a product of a race
between the photons and the sound wave that's propagetting out.
But because there is no soundwave, there's no shockwave, there's
nothing there to absorb that radiation. All the radiation just
flies out, and so it looks quite different. And what
that means is that nuclear weapons are dangerous over much
greater distances in space because the radiation is not absorbed,
(31:54):
and so if a nuclear bomb blows up in space,
you can get significant radiation damage from it, even if
you're much further away.
Speaker 2 (32:01):
Say we exploded a nuke somewhere in our solar system,
would that radiation potentially hit.
Speaker 1 (32:09):
Earth, you still are protected by physics is one over
distance squared law. The same with the Sun is like
one hundred times dimmer if you're ten times further away,
or electric fields go down by a factor of four
if you're twice as far from the charge as all
these one over distance squared law in physics, which actually
not hard to understand. Like from a geometrical point of view,
(32:29):
you imagine, like particles flying out from a nuclear bomb
or photons flying out from the Sun, the same certain
number are released, and then as the radius grows, those
particles are now spread out over a larger and larger sphere,
and the area of that sphere goes like four pi
are squared. So as that sphere gets larger, the same
number of photons or dangerous particles are spread out over
(32:52):
a larger area. So for any given area of the
radiation drops like one over the distance squared. And so
if you're far away from this thing, you'll be safe. Now,
on Earth, you can be just a couple of miles, two, three,
four miles from an explosion and be mostly safe from
the radiation because so much of it is absorbed into
the atmosphere. But in space you've got to be like
(33:13):
forty fifty sixty miles to be as safe as you
would be on Earth, because essentially there's no protection. Right
on Earth, you're kind of protected from this nuclear bomb
by the atmosphere or by the ground, or by the water,
but in space there's nothing there to shield you.
Speaker 2 (33:28):
Right, So is this radiation constantly spreading out or does
it kind of stop dissipating after a while. Does it
keep dissipating forever until it just sort of has equalized somehow?
Speaker 1 (33:41):
Yeah, great question. Well, the initial explosion again is very brief.
The actual nuclear detonation doesn't last very long, and so
what you're thinking about is sort of like a pulse,
like all this radiation in a sphere that's traveling out
very very fast, in many cases actually at the speed
of light, and then getting dimmer and dimmer as it goes.
And so it's really just like a pulse that travels
through space, washing over things and damaging them.
Speaker 2 (34:03):
How long does that pulse last? Does it last like
seconds or hours or years?
Speaker 1 (34:09):
Well, the pulse itself would last for less than a second.
The actual explosion itself doesn't take very long, so it's
not like sitting there stewing, continuing to produce pulses of energy.
It's one very high intensity pulse over a short time.
But it's various kinds of radiation. Also. There's photons, very
high energies, and then there's neutrons, of course, and there's
also electrons. And the electrons can be particularly damaging and
(34:30):
also kind of fascinating because the electrons are traveling at
very very high speeds and they tend to radiate. So electrons,
when they move to a magnetic field or anything they
change direction, they radiate photons, and so that creates this
electromagnetic pulse. So all these electrons create this electromagnetic pulse
which can disrupt the flow of electricity or damage any
sort of electronics. And you see this in science fiction
(34:52):
all the time, right, that like electronics are blacked out
when there's a nuclear bomb, And that's really true. It
will create like pulses of energy in electronics.
Speaker 2 (35:00):
That's really interesting. So if you're a spaceship, right and
you're riding up and someone decides to blow up a
nuke in front of you, you're really screwed in many
ways because you've just got a huge dose of radiation
and then all of your electronics on your spaceship are
going to get messed up by that EMP pulse. Is
there anything else to look out for if you're on
(35:20):
that spaceship cruising and someone blows up a nuke, Miria, Well.
Speaker 1 (35:26):
If you're on that spaceship, I really hope you have
a special leadlined room to protect yourself, like we do
actually on the space station. Because the Sun, of course,
is a huge source of radiation, and solar storms can
generate EMPs and also other kinds of radiation which can
damage satellites and people, and so they have a special
room on the space station where the astronauts can go
(35:46):
like a panic room when there's going to be like
a high radiation solar weather event. And so I hope
your spaceship is outfitted with one of those, because if
somebody blows up a nuclear bomb, it's going to damage
your ship and also damage you if you're within tens
of miles.
Speaker 2 (35:59):
We know that for like when you explode a nuke
on Earth, long after the explosion, it's irradiated everything around,
and depending on how large the explosion is, the nature
of it, like with Chernobyl, the area in that exclusion
zone is still radioactive. Like it's still not necessarily a
safe place to be. It's not like you will immediately
(36:22):
get radiation poisoning and die if you step foot in
the exclusion zone, but you can get sick depending on
how long you're in there and how close you get
to the center where the explosion happened. But what happens,
like with this explosion in space, is there an area
like a sort of point in the middle that continues
(36:43):
to be sort of radioactive or does that without anything
to really absorb it, It just keeps moving until it
hits something that it can be absorbed by Yeah.
Speaker 1 (36:53):
Great question. And remember, of course Schernobyl was a nuclear
meltdown of a reactor, not an actual nuclear explosion, so
nothing blew up, so you still have a lot of
the fuel and all that stuff there in that same location.
The larger exclusion zone is because of the weather and
the air that pulled the smoke and the radioactive particles
further away, so there was never actually a nuclear explosion there.
And in space, you blow this bomb up, there's not
(37:15):
going to be really anything left in the location of
your detonation to poison people. Everything is going to fly
out because there's nothing stopping it, right, There's nothing holding
it in place at all, So you haven't like poured
radiation into a bunch of nearby dirt or water. Everything
is just going to flow away. So you could probably
come back in, you know, a month or so after
(37:36):
the nuclear bomb, and the space would be no different
from when you started. All of the dangerous elements would
be flying out from the source in lots of directions,
poisoning people or causing damage as they hit them, But
the actual location of the nuclear explosion in space isn't
going to be like affected in any way, have we.
Speaker 2 (37:53):
Ever thought to blow up a nuke? And I mean
I'm sure we've thought of it, but have we ever
actually done it before?
Speaker 1 (38:00):
Oh? Yes, we have actually blown up nuclear weapons in
lots of places. We've blown them up in more Unfortunately,
we've blown them up above ground, we've blown them up underground,
and we have actually done a nuclear explosion in space.
So we don't even have to wonder about what this
looks like. We know we have pictures.
Speaker 2 (38:18):
Well, that sounds terrifying. Let's take another quick break. I'm
gonna watch the little duck and cover turtle learn some
good lessons, and when we get back, I want you
to tell me about blowing up nukes and space, which
apparently we have already done. So we are back to
(38:48):
that little duck and cover turtle. He's got a turtle shell,
but he's also got a helmet redundant. Anyways, now we're
going to talk about how we actually have already blown
up a nuke in space. It terrifies me that we
may have pissed off some aliens and many generations from
now they'll finally reach us and give us a real scolding.
(39:10):
But Daniel, what happened? Why did we blow up space.
Speaker 1 (39:14):
So nuclear testing started in nineteen forty five with the
Manhattan Project. The US, of course the first country to
develop these things and to test them and then to
use them in war, where thousands of people were killed horribly.
And since then there's been about two thousand nuclear explosions
conducted by humans. And in the early days it was
free for all, there were no laws. People were blowing
(39:35):
stuff underground, above ground, et cetera. But we pretty rapidly
realized that blowing up stuff in our atmosphere was a
bad idea, creating radioactive particles and fallout. They could drift anywhere.
We blew up a bunch of islands, which is terrible,
destroying people's homes. And so that was in the fifties,
and things were of course very tense between the US
and the USSR. The US had stopped atmospheric testing, but
(39:57):
in the early sixties the USSR started atmospheric testing again,
which was sort of part of a larger political struggle
within the USSR to like stand up to the US.
We really should have like a Russian political expert on
to tell us about why they started that up again.
But in nineteen sixty two, the US wanted to know, like, well,
what happens if you blow up a nuke in space?
They were basically curious, and they didn't want to do
(40:19):
any more atmospheric testing, and so they tested a nuke
over the Pacific in July of nineteen sixty two.
Speaker 2 (40:26):
So I'm thinking, like, if we blow it up just
a little bit above our atmosphere, that's not going to
cut it. Like how far away did we go? Because
you know, it seems like if you're too close you
can still have an impact on the Earth that you're
not going to want.
Speaker 1 (40:43):
Yeah, exactly, if it's too far away, you won't be
able to see it because we don't have great instruments
in space. If it's too close, then it's basically in
your atmosphere, and said they chose an altitude of two
hundred and forty miles above the Earth's surface, and they
launched a one point four mega ton nuke from Johnston Island,
which is like fifteen hundred kilometers southwest of Hawaii. And
(41:05):
the idea was like, well, if something bad happens, does
have it happen over less populated areas, I guess, And
people imagine like, oh, that's far enough away from Hawaii
to not be a big deal, right, And they check
with a scientist and the sounds just like yeah, right,
no problem. Turns out those scientists were wrong. Oh boy, yep. Scientists,
especially physicists, can be wrong.
Speaker 2 (41:25):
Yeah, which is a big deal when you're talking about
a nuke and talking about people just trying to live
their lives. And then you're like, but we're curious to
see what this will do. Yikes.
Speaker 1 (41:37):
You can google this thing. It's called starfish prime and
just as we expect, it makes a spherical explosion. So
you don't get like a mushroom cloud that's a product
of blowing up in an atmosphere. You just get this
spherical explosion. It's not completely perfectly spherical, because the nuclear
bomb is not perfectly symmetric. There's like some small differences
in how the explosion happens based on exactly how the
(41:59):
fuel is ranged. But it's almost completely spherical.
Speaker 2 (42:03):
It kind of looks like a flower or like a
drawing of a sun where you kind of make the
outsides a little spiky, but yeah, it is pretty round,
and you've got like this bright white point in the middle,
and then you've got sort of a blue corona around it,
and then a larger white corona around the blue. What
is that sort of color difference. Why do you have
(42:24):
that like bright white light and then this blue and
then bright white light again on the outer edges.
Speaker 1 (42:30):
Yeah. I think it's similar to the effects we were
talking about in the atmosphere, that there is some debris
that comes out of the explosion, and then the radiation
that's emitted after that is partially absorbed by some of
that debris, some of those heavier ions that are created
by the explosion, So you get this multiple effect with
the products of the explosion then absorb things that are
later produced in the latter stages of the explosion. And
(42:53):
it was a pretty dramatic event on Earth.
Speaker 2 (42:55):
Yeah, I mean where people told this was going to happen.
Speaker 1 (42:58):
People were told it was going to happen, and even
the newspapers were aware, and they kind of advertised it.
There's a headline in the Honolulu Advertiser, which is a newspaper,
which says, in blast night maybe dazzling, good view likely,
And a bunch of hotels in Hawaii had like rooftop
parties for people to watch this nuclear explosion happen.
Speaker 2 (43:16):
I would be in a basement, but what would it
look like to someone on one of these rooftop parties.
Speaker 1 (43:24):
So you can't see the actual explosion the same way
because of the atmosphere, but there aren't these great pictures
that people took from Hawaii. And you see all this
air glow. You see all this red light because the
radiation has hit the atmosphere and it's excited a bunch
of oxygen atoms which then glow. So it's basically like
heated up the atmosphere which then glows in this red light.
Speaker 2 (43:45):
I mean that seems spectacular but also maybe kind of
apocalyptic looking. That would scare me.
Speaker 1 (43:52):
Yeah, And then after the actual explosion there's a massive
aurora scene for like thousands of kilometers. You know, the
Northern Lights. These are high energy particles hitting the atmosphere.
They're mostly funneled up to the Northern and Southern poles
because of the magnetic field. But when a huge number
of high energy photons hit the atmosphere, they make the
atmosphere glow and you don't just get red, you get
(44:13):
greens and blues depending on exactly what it is that
has been like zapped and energized and then re emitted.
And so whereas you don't normally see auroras in Honolulu,
they had this massive aurora which stretched for thousands of
kilometers over the Pacific.
Speaker 2 (44:28):
Well, maybe worth it to take a chance to accidentally
blow up a bunch of people, But you did mention
that the scientists had not quite calculated this right, So
were people actually in danger here? Like was there some
negative consequences to this?
Speaker 1 (44:46):
Well, it like blew out street lights in Hawaii?
Speaker 2 (44:48):
Oh wow, So this.
Speaker 1 (44:49):
Electromagnetic pulse that was created went much further than the
scientists thought. I think they didn't realize how much of
that is absorbed by the atmosphere when you blow this
thing up on Earth, or when you blow it up underwater.
And so the radiation effects of this bomb in space
were much broader than they had anticipated. And so, yeah,
there were effects on Hawaii. They destroyed a bunch of
satellites that were up in space. Back then, there weren't
(45:12):
that many satellites. This is the beginning of the space era,
so only like six satellites were destroyed. These days, you
blew up a nuclear weapon and that kind of location,
you destroyed dozens of satellites, billions of dollars of damage,
and people were able to see this thing for like
thousands of miles away. People on Fiji described the light
show as breathtaking.
Speaker 2 (45:31):
Wow. I mean, so you mentioned that the radiation spread
out much further than they had suspected. Did that negatively
impact Hawaiians? Did that hurt people on the island or
did it not actually have too much of a human impact.
Speaker 1 (45:45):
It doesn't have very much of a human impact because
fortunately we are under the atmosphere, which is a really
thick blanket to protect ourselves from a lot of this radiation.
And so really the only impact in Hawaii was the
dramatic light show and the pulse from the EMP, which
damaged some electrical devices and blew out street lights and
dumped a bunch of energy basically in any conductor that
(46:05):
can absorb electromagnetic energy for hundreds of kilometers, and so
satellights and street lights are basically the only real damage.
There may also be some very small amounts of radioactive material,
but distributed over such a large area that doubt has
really any impact on it, like human life.
Speaker 2 (46:21):
Well, it could have gone worse, it could have been.
Speaker 1 (46:25):
Wronger, and actually some scientists were wondering if this was
going to have a long lasting effect on other features
of nearby space. Remember that near the Earth there are
these huge bands of radiation. They're called the Van Allen Belts,
and they're basically just particles like whizzing around the Earth
that were discovered in the fifties whence we sent up
our first space missions. That as you leave the Earth
(46:47):
you pass through these bands of massive radiation. There's an
inner belt and there's an outer belt. They're not very
well understood, and at the time they were seen as
like an impediment to space travel, that if you go
up into space, you have to survive passage through these
basically radiation guns. And some scientists were wondering, if we
blow up a nuclear weapon in these radiation belts, maybe
it would like disturb them or dissipate them, though some
(47:09):
people were sort of hopeful that it would blow up
the radiation belts, which to me is kind of crazy.
It's like, before you even really understand these things and
their purpose and their benefits and their detriments, you want
to just like blow them up and see what happens
to life on Earth.
Speaker 2 (47:22):
Yeah, I mean, it's kind of looking forward and not
looking at the current situation right because you're thinking, like,
let's make space travel easier. But we have this functional
planet that we're pretty cozy on, so you might not
want to mess that up for some kind of future
space highway. I think that it is a lot of
(47:42):
decisions that we make we don't often think about, like,
but how will this impact the planet before we build
this space highway or regular highway? Did it impact these
radiation belts or did it not really have a permanent impact.
Speaker 1 (47:57):
I had basically no impact on the radiation belts, which
contain an enormous amount of energy which could not be
affected by one nuclear bomb. But this nuclear explosion did
have sort of shockwaves through the political climate on Earth.
Things cooled down a little bit, and in nineteen sixty
three they passed a partial Test Ban treaty which prohibited
all nuclear testing except for underground testing, which was seen
(48:19):
as safer because it really is very well contained. And
so for about thirty years, the US and Soviet Union
did a bunch of underground tests until they were prohibited
in nineteen ninety six. I still remember my dad traveling
to the Nevada test site to participate in some of
those tests. So the US was still testing nuclear weapons
(48:39):
into the nineties. We have not blown one up since then.
The last nuclear test from the US was in the nineties.
Speaker 2 (48:45):
It really feels like such a scary time though, during
the Cold War, when you're having all these tests going on,
you wonder about how many close calls we had in
terms of a test going wrong where it actually hurts people,
or a test that happens is misread by like say
that Russians are you know, by the US, and we think, well,
(49:06):
we're being attacked and that starts a whole cascade of nukes.
It feels like this wild West time where we were
just i mean, maybe not playing around with nukes, but
the fact we were doing so many of these tests,
and it feels like we just kind of escaped some
kind of horrible fate by the skin of our teeth.
Speaker 1 (49:26):
We certainly did. If you dig too deep into his history,
it's terrifying. There were times when like a flock of
seagulls were mistaken for the launch of a nuclear weapon.
Another time when like a training tape was accidentally loaded
into a computer which became convinced that the Russians were
attacking us. It's really terrifying how close we came to
all out nuclear war several times. And you know, the
(49:47):
US and the USSR haven't tested nuclear weapons since the nineties,
but you know, India and Pakistan detonated nuclear weapons in
the very late nineties, and then of course North Korea
has done tests fairly recently of nuclear weapons. So it's
not like we're out of the woods in terms of
nuclear weapons. Nope, yeah, exactly. Israel actually is the only
(50:08):
country we think has nuclear weapons but has never done
a nuclear test that we know of, that we know of.
Speaker 2 (50:14):
Yeah, I mean, it's interesting because at the start of
the Russian Ukraine War, I started following a bunch of
nuclear proliferation experts and sort of people who understood the politics,
who understood the science of nukes, because I was terrified,
and I'm not gonna say I got less terrified after
(50:36):
hearing what the experts had to say. I think the
knowledge of exactly the kind of circumstances that we were
in and stuff was helpful. Like, even though the Cold
War is over, the fact that there are so many
nukes out there, it's terrifying, so we should probably send
them all the space blaw them all up put them
in space.
Speaker 1 (50:55):
I guess if I had to choose where to blow
up nuclear bombs, I probably choose to blow them up
in space, over the atmosphere or anywhere else on Earth.
But it is really interesting to understand what happens to
a nuclear bomb when you blow it up in space.
It turns out to be quite different from what happens
in our atmosphere. It doesn't dump that energy and create
a shock wave. It's basically like a little miniature sun,
(51:16):
and so there is no shockwave to hurt you, but
that radiation will travel much much further and damage things
that are much further away, especially electronics. So let's hope
that we don't end up in a nuclear space war
anytime soon.
Speaker 2 (51:29):
And if you're flying your spaceship and you want to
fire some nukes, wear sunglasses.
Speaker 1 (51:35):
And be careful microwaving your soup, and put a lid
on your blender when you make that strawberry smoothie.
Speaker 2 (51:39):
All of this is practical advice.
Speaker 1 (51:42):
Thanks Katie very much for joining us on this exclusive episode,
Thanks for having me, and thanks to all of our listeners.
Tune in next time. Thanks for listening, and remember that
Daniel and Jorge Explain the Universe is a production of iHeartRadio.
(52:03):
For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to your favorite shows.
Hosts And Creators
Daniel Whiteson
Kelly Weinersmith
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