How was radiation discovered?

X-rays, U-rays, and cosmic rays! Hear the story for how we came to understand that our world is filled with invisible dangers.

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Episode Transcript

Speaker 1 (00:08):
Hey, Daniel, would you risk your life for science? It
might depend on the science we're talking about. Would you
risk getting eaten if you've got to meet Adians for example? Tempting,
but I'll pass. How about would you risk speghettification if
you got to see the inside of a black hole?
You know, I might actually take that trip. Or would

(00:29):
you risk deadly radiation to understand the nature of matter? Actually,
I've kind of already done that. One really does a
large hadron collider generate deadly radiation? It does, But that's
not how I've been exposed. How have you been exposed
to radiation? Well, flying the switzerlanded back like a thousand times,
you get a lot more radiation at high altitude, really

(00:49):
you have. Every Transatlantic trip is like a chest X ray.
I thought you said you've been been by a radioactive
Swiss spider, and I gained that spider's proportional physics, smart
and chocolate making ability. I am jorhandmade cartoonists and the

(01:19):
creator of PhD comics. I'm Daniel. I'm a particle physicist,
and I like to think of myself as radioactive. Are
you technically radioactive? Are most people radioactive? At some level,
like bananas are radioactive. Yeah, so you're probably more radioactive
than most people. But I grew up in Los Almos,
New Mexico, where we like to say we all glow
in the dark. Really, I did grow up in Los Almos,

(01:44):
but we don't actually like to say that. Well, I
do eat a lot of bananas, and I do have
a certain glow about me, i'd like to think, but yeah,
Welcome to our podcast. Daniel and Jorge explain the university
production of our Heart Radio, in which we shine a
radioactive glow into all the mysteries of the universe, the big,
crazy things that are out there tearing the universe apart,
the powerful forces that are holding it together, the things

(02:06):
far from home, and the things right here in our backyard.
All the mysteries of physics revealed and explained to you.
That's right, we radiate knowledge and give you an X
ray view of all of the amazing secrets that are
out there to discover in the universe, and all of
the secrets that are yet to be discovered. And all
the while you can stay home and safe, tucked into

(02:26):
your couch, sipping that mug of tea and learning about
the universe. No tinfoil hat needed or leadline hats. That's right.
This counts exactly zero as part of your annual dose
of radiation, even though you'll be learning all about it.
It's right. Well, we're technically getting to people through sound waves,
not light weights or radiation. That's right. But actually radiation

(02:47):
is sort of any sort of energetic particle or wave.
So sound is technically speaking a kind of radiation. So
we are radiating your ears with our voices. What no it,
I said a limit? Get you like, if I throw
a baseball, I'm radiating a baseball. Baseballs are radiation, yes, absolutely, Now,

(03:07):
the technical definition of radiation is sort of weirdly broad.
Any kind of light, any kind of particle, any kind
of way that transmits energy is radiation. But practically speaking,
when we talk about radiation, we mean very high energy
particles or higher energy waves that are going to deposit
a significant amount of energy. And so a flashlight or

(03:28):
this podcast are not typically categorized as radiation, even though technically,
according to physicists it is. Well it's a very loaded word,
isn't it. I mean, especially like in the eighties. I
feel in the nineties, you know, radiation was such a
negative thing, and nobody wanted radiation and the thing that
made you sick. Yeah, exactly. Radiation can be pretty dangerous.

(03:48):
They're basically these little invisible bullets flying through the universe,
and they can do real damage. They can fly through
your cells, they can bust up your DNA, they can
cause you cancer. And so radiation definitely is something to
think about and worry about. And it's one of these
things in the world that's not visible to our naked
eye yet turns out to be pretty important. So it's
a key that tells us that there's a lot going

(04:10):
on in the universe that we can't directly see. Yeah,
So a big question is how do we even discover
radiation or even come to believe it exists if it
is in fact invisible. Yeah, it's part of this story
of peeling back the nature of reality and figuring out
that the universe has a lot of stuff going on.
But to me, it's always fascinating to figure out how

(04:31):
that came to be, how that understanding sort of filtering
into human minds, because here we are standing on the
shoulders of giants, understanding all these things about the way
the world works. But this required a real shift in
people's understanding of the nature of the universe. So I'm
always super interested in those moments, like what was it
to convinced people? What experiments did people do that revealed that,

(04:53):
because I hope that will help us understand what experiments
in the future might again change the way we think
about the universe. Yeah. So usually people assign this discovery
to Madame Curie and her experiments, but there's actually more
to the story, right there is she did not, in
fact discover radiation. She won a couple of Nobel prizes.

(05:13):
She was quite a genius. She discovered a lot of stuff,
but you can't give her credit for discovering radiation. It's
a fascinating story. Well you can't even define it. I mean, sure,
then nobody discovered radiation or everyone discovered that's right. The
first little swimming organism that developed an eyeball, I supposed
discovered radiation when it used photons to guide itself around

(05:34):
the primordial soup on Earth. I suppose, yeah, right, like
the first organism to use or detect light. Right, that
definitely predates humanity. But I think we should focus on
the kind of radiation we're talking about, which is you know,
high energy particles or waves that come from like radioactive decay,
things that are different from the normal kinds of radiation
we used to live our lives. We're talking about a

(05:55):
change in how we've understood the universe. Okay, so it's
a invisible well, potentially dangerous and obviously very scientifically significant.
But how was radiation discovered? That's a big question, and
that's the question we're exploring today. So to the end
the program, we'll be talking about how was radiation discovered? So,

(06:20):
as usually, we were wondering how many people out there
knew how radiation was discovered? So thank you to everybody
who have volunteered their answers to these tricky physics questions
without referring to any reference materials, Google or Being or
ask Jeeves. And if you would like to participate in
future Baseless Speculations for the podcast, please write to us
two questions at Daniel and Jorge dot com. Maybe that

(06:42):
should be the name of that website, Daniel Baseless speculation
dot com. You might get a lot of hits. Yeah, exactly.
We just pointed to our book every single time we
have no idea. Dot com is the answer to all
these questions. Oh, interesting, interesting marketing technique. Lure people in
with a juicy website and then sell them a book.

(07:03):
Yeah exactly. I think they call that click bait. So
think about it for a second. If someone approached you
and asked you if you knew how radiation was discovered,
what would you say. Here's what people had to say.
I have no idea, but I think it has something
to do with Marie Curry playing around with some kind
of radioactive substance and like X raying her hand or
something like that. Radiation was discovered by Madame Cury. I

(07:24):
just know that was discovered Marie Cury. I believe radiation
was discovered by Marie Cury. I don't know how she
did it. She was probably experimenting with what became known
as radium and saw it glowing. I think radiation was
discovered in the eighteen hundreds when some radioactive material uranium

(07:47):
was glowing in the dark or was unusually hot. All right,
it looks like Marie Curry and the Curys have a
pretty good policies because most people went to them as
the discoverers of radiation. Yeah, she definitely ensconced in popular
culture as somebody deeply associated with radiation. And you know,
she actually did have a good publicist late in her career.

(08:08):
She did a whole tour of the United States giving
talks all about radiation stuff. So she became quite famous
and associated with radiation. So that has lasted up to
the present day, almost a hundred years later. Right, Well,
we don't want to take away anything that she did
or that the Crease did. It's really more about definition.
I think I think she discovered a particular type of

(08:29):
radiation or I guess we'll get into that, but generally speaking,
it kind of seems like radiation maybe is a broader
concept than most people assume it is. There's definitely that,
and she made important contributions and discovered particular kinds of
radioactive elopments. Will dig into that, but you're right, radiation
is a sort of a broader set of things. Radiation
is not just uranium decays and shoots out deadly particles.

(08:53):
There's a broader set of things. We consider radiation not
just ordinary light. But it starts, for example, with X rays,
Like X rays are just high energy photons, but we
consider them radiation. Yeah, I guess you're saying earlier that
any light is considered radiation. Even sound is considered radiation,
even like heat, I guess heat is radiation. Yeah, exactly,

(09:15):
you radiate heat. You run a lap and you get
really hot, you are radiating heat out into the universe.
And everything in the universe that has a temperature gives
off heat, and so everything in the universe is radiating constantly.
Radiation is everywhere. But that's sort of again the sort
of technical physical term for it. When we talk about radiation,
we think about sort of damaging radiation, radiation that's long

(09:36):
been invisible to us and reveals something different about how
the world works. And it was really crucial in understanding
things like the nature of the atom and the deep
structure of matter. Right, Well, we knew about light for
a long time. I mean, it's it's kind of in
the Bible, Daniel, that they'll be light. It was like
the first thing is that a reference book. I wasn't
familiar with that, you know, God at all. I think

(09:59):
there's some rata for that one. It's probably the most
impact factor of wall puplications in the history of man. Yeah,
I submitted something, but it got rejected by the referees.
So I mean of course, we've known about light for
a long time, So I guess when when do you
draw the line as us having discovered radiation, Like, is
it x rays? Is that the first kind of you know,

(10:21):
powerful kind of radiation invisible that we've discovered. Yeah, I
think the discovery of X rays really marked the turning point.
It's the time we discovered that there are ways to
transmit energy or other kinds of light that are different
from the kind of visible light we were familiar with.
And this specifically was a kind of light that we
saw could sort of pass through walls and pass through barriers,

(10:43):
and so it really was doing something different from the
kind of visible light we were familiar with. And that's
exactly how it was discovered. I see, like, if you're
shine a flashlight, it gets blocked by the wall. But
if you shine an X ray tube at at a wall,
it will go right through. It will go through most
of it. Yeah, exactly. And that's why we call it,
you know, X raying something because X rays passed through
the soft tissue of your body, but not your bones,

(11:05):
and so they reveal what's going on inside. And so
radiation is interesting because they can do these things in
visible light can't do. But also because it has this power,
it penetrates and so it reveals what's the inside, all right,
So then how do we discover X rays? So X
rays discovered by this guy Runken. And this guy was
a character. I think you'd like this. He actually was

(11:26):
kicked out of high school as a student because he
drew a caricature of one of his teachers, which is
not very flattering, and so he's sort of a physicist
and a cartoonist. I almost got exposed from my school
for the exact same reason, actually exactly. I didn't this
caricature one teacher, I did all of them. Well then
maybe there's a Nobel prize in your future. Yeah, stay tuned.

(11:48):
But he was doing experiments at the time with these
things called Crooks tubes. We talked about these before because
they were how electrons were discovered. They're basically just these
glass tubes that are mostly have vacuum in them. You
have an anode and a cathode with voltage across them,
and so you pull electrons off. People have seen these
seeing before and you get these beams, these glowing beams

(12:08):
inside that look really cool because the electrons were like
knocking off atoms and ionizing them, and people were doing
lots of experiments with them trying to understand what they were.
And again J. J. Thompson used them to discover the electrons.
But Runkin was really interested in whether or not the
rays that were being produced inside these tubes could pass
through the glass. He was curious to see what they

(12:30):
could get through. But these rays were originally electrons, like
like a stream of electrons or or were they light?
These were a stream of electrons and that's what J. J.
Thompson discovered. But the glow that you saw that was
visible light. And so the electrons would knock into a
few atoms inside the tube, ionized them, they would give
off some light, and then they would decay back to

(12:51):
their ground state. So what people were sort of ooing
and aweing over, we're seeing a beam of electrons exciting
the gas inside the tube. Okay, but just clear the
the X ray is not the electrons and X rays
is a light beam, right, that's right. The X ray
is not an electron electron as a particle, and X
ray is a piece of light. Right, It's a photon
of a specific energy. But this is what Runkin started

(13:13):
with He started with these tubes and he was playing
around with them, and he accidentally discovered that they also
generate X rays, like along with the electrons or when
the electrons hit stuff. So the electrons, one of the
things they do is they generate a glow that you
can see with your naked eye, but they also sometimes
generate X rays, and we can get into the whole
details of exactly how that happens, how they're accelerated and radios.

(13:35):
But sometimes they generate visible light in our spectrum, and
sometimes they generate photons that are higher energy, and these
are X rays. So he was interested in understanding, like
what is this thing generating? Can it pass through the
glass walls of the tube. So what he did was
he built a big black box, like a light proof box.
And his idea was, I'm gonna put this box around

(13:57):
my tube. I'm gonna see what light is show mind,
and the inside of the box from this tube, so
I can see sort of like you know what, light
comes out of the tube and hits the side of
the box. So I guess he wanted to know. He
thought he was trapping the light that was coming from
the Catherine tube, but actually he saw that the light
kind of leaked outside of it. Yeah, exactly, he turned

(14:19):
off the lights in his laboratory just to sort of
like get things warmed up, and he was going to
look inside the box to see if he could see
like light on the inside walls of the box. But
before he did that, he noticed that he saw this
weird light outside the box on the wall of his laboratory,
and he was like, what's that over there? And it
turns out he had a special sort of screen over

(14:40):
there just happened to be in the right location that
can receive X rays and glows when it hits X rays,
And so he discovered that the light doesn't just go
through the glass. It also went through his box all
the way out to the side of his lab and
hit this special screen. So it was quite by accident
that he discovered these X rays. Whoa was a special

(15:00):
screen that he just had that that seems like such
an accidental discovery. It's totally an accidental discovery. And it's
a special screen covered with a material that phosphoresces, so
it absorbs photons at one wavelength and then it gives
off photons at a different wavelength. So it's a wavelength
shifting effect. And this is the kind of thing we
do all the time in physics these days. We absorb

(15:21):
photons of one thing and it give off photons of
another color. So he happened to have a screen covered
in this material. It was a barrio phosphorescent material that
could absorb X rays and glow in the visible light.
And he was like, what's that over there, and did
a bunch of experiments, and he discovered that it could
pass through his box, and it could pass through lots
of other things, but that it wouldn't pass through metal,

(15:43):
for example. Now, was this the first time that, you know,
humans kind of got the idea that light can go
through things, or did we already kind of know that
there are things in nature that can go through things? Now,
this is the first time we understood that light could
pass through something that we thought was the wise solid.
And famously, the first X ray picture he ever took

(16:04):
was of his wife's hand, and you could see her
hand with its wedding ring on it, and he showed
it to her and he thought, this is gonna be
so romantic and awesome. She was actually really creeped out,
and she thought oh my gosh, I've seen my own death,
because she'd seemed like her own skeleton inside her hand.
And I think it really changed the way people felt
about like the solidity of stuff. Right, you think of

(16:25):
yourself as solid and opaque, but you're not. You're transparent
in some wavelengths of light, in your opaque in other
wavelengths of light. So then from that they they invented
X rays, you know, for medical purposes. Yeah, things happened
really fast because people very quickly understood how powerful this was.
Like you could see broken bones inside the body, or
you could see if you're tiled, it's swallowed something metal,

(16:48):
and so just seeing inside the body without having to
cut it open was immediately and enormously powerful. And within
a year people were using it in hospitals. And it
wasn't hard to make X rays, like Crookes tubes were
a thing that already existed, and so the technology sort
of was all around. It just took the right combination
of knowing what to do and how to do it.

(17:08):
And he went on to win the first Nobel Prize
in physics just a few years later. Really the first one,
the first one, yeah, exactly, and you know it sort
of satisfies all the requirements. It teaches you something deep
about the universe and also made a very big impact
on humanity. Wo and it sounds like it was really
more about discovering the screen is a combination. You have

(17:31):
to have the radiation and you have to have a
screen that can receive it. Right, X rays are invisible
to us, and so if they can just fly through
the universe and fly through a wall to see them,
you have to put something in their path that they
will interact with and that transform that information into something
your eyeballs can see. All right, Well, that's X ray radiation,
which is light radiation. But I guess the more popular

(17:53):
kind of radiation, or at least in people's consciousness, is
particle radiation. And that's where the curies come in. And
so let's get into that kind of radiation. But first,
let's take a quick break. All right, we're talking about

(18:19):
radiation and how it was discovered and how you should
probably wear sunscreen when you're outside and near particle colliders?
Would that help Daniel and near physicists? Probably because they
they're so shiny and beaming. Well, they just had to
do these crazy experiments which sometimes you know, do damage
their own help. All right, Well, I guess we talked

(18:40):
about X ray radiation, which which is really just light
at higher frequencies that can pass through things, and some
people associate that with radiation. But maybe the more common
type of radiation that people think of is kind of
the dangerous kind, I guess, the nuclear kind, and that's
more like particle radiation. Yeah, and X rays, of course
also dangerous. They can deposit a lot of energy in

(19:02):
your skin, and they can cause cancer and UV radiation
all that stuff, So it's definitely dangerous. But particle radiation
also very dangerous and more famous because I think of
the radioactive decays involved in nuclear physics, for example. But
particle radiation was discovered pretty soon after particles were discovered. Remember,
the whole idea of a particle didn't really exist until J. J.

(19:25):
Thompson discovered the electron in the late eighteen hundreds. You know,
this notion that everything was made out of tiny little bits,
and we could find those things and we could associate
like a tiny dot in space with mass and with
other quantities. This is a whole new idea in physics
at the time. It's not something which had existed for
a long time right before, Like light was just like

(19:45):
a beam, right, like pure energy kind of. Yeah, the
wave properties of light were dominant, and people thought about
light as a wave. They thought about matter and waves existing.
But the whole idea that things were made out of
tiny particles, or that these tiny particles could fly through
space invisibly and hurt you, for example, this was brand new,
but it was discovered pretty soon after the electron was

(20:07):
discovered again in the late eighteen hundreds, like the next year. Yeah,
and it was spurred by the discovery of X rays.
Like everybody in the world was very excited about the
X ray discovery made a huge wave in the world
of physics. Pun definitely intended and I thought it was unintentional. No,

(20:28):
And this bit about the screen that you latched onto.
This guy Beck Carrell, he also was really excited about that.
He thought it's really cool for something to absorb energy
in one wavelength and emit in another. To absorb one
kind of energy and emit another kind of thing. It's
called luminescence. And he thought he was really exciting and
he wanted to follow up in this and make also

(20:49):
some kind of crazy discovery and he came from a
long line of physicists people have been studying this sort
of kind of thing of generation of heat and energy.
So he did a series of experiments with uranium crystals
and he was the first to discover particle radiation. So
he actually came well before the curies. So interesting. Well,
apparently his father was also a physicist and a radiation

(21:11):
physicist too. That's right. He actually came from several generations
of physicists and they all had the same job. They
all had like the same chair in the head of
the natural science department in Paris, and so it was
sort of like a hereditary position almost. He's like a
legacy physicist in France. So his father looked into radiation,
but he didn't discover it. His father also had been
studying uranium crystals, and after Beccarel discovered radiation, people went

(21:35):
back and looked at his father's notebooks and there was
plenty of evidence in his father's notebooks to document evidence
of radiation, but his father just sort of didn't put
it together. And this is something you can do in physics.
When people make a big discovery, you can look back
at people who might have discovered it. If they had
only believed their results or followed up on something they
didn't understand. It sort of missed opportunities in physics. I

(21:59):
one know, if you want people to see that or
it's just kind of a little bit embarrassing from a
physics point of view. I think it's super fascinating from
a sort of history of science point of view. You
get a result that you don't understand or doesn't make sense,
do you always follow up on it or do you
sort of leave it behind? And those missed opportunities, you know,
those times when signs could have gone differently if somebody

(22:21):
had taken a different path and thought about something different
or had a different conversation at a conference. It's fascinating
to me to imagine the sort of alternate universes in
which we discovered things in different orders, because that's what
everyone wants in their tombstone, you know. Could have won
a Nobel prize. Yeah, But they did these experiments with
uranium crystals. So uranium was a thing, it was known,

(22:43):
it wasn't understood what it was doing, but they were
doing early studies with it. And essentially what they did
basically is they just put it next to photographic plates,
Like photographs were a thing back then, so they just
wrapped them in paper and put them next to photographic plates,
and they wanted to see what would happen. Oh right,
because they had photo grass at that time, and that
it is also kind of like magic, like light hits

(23:04):
it and or not hit it and it changes color. Yeah, exactly.
It's a special process that absorbs photons and develops in
a different way based on you know, the amount of
photons that hit it. To really sort of awesome chemical
process for absorbing things and taking data. And back before
we had computers and digital cameras and stuff, everything was analog.
This was a powerful way to do science experiments. But

(23:26):
Beckerel sort of started off on the wrong track. Remember
he was interested in luminescence. He thought if you took
these uranium crystals and you left them in the sun,
that they would absorb a bunch of energy from the
sun and then they might glow in some new invisible way.
So he put these uranium crystals in the sun, then
he wrapped them in paper to block an invisible light,
and he put them next to these photographic plates. So

(23:48):
he was hoping maybe he would like find a new
way to make X rays, or that they would admit
in the X ray because X rays had just been discovered,
all right, So he saw radiation and X rays and
he thought, hey, I wonder if that works everything. So
do do you think he tried a bunch of different materials,
not just these uranium crystals. Yeah, he tried a bunch
of different materials wondering what would glow. But these uranium salts,

(24:09):
these uranium crystals were the things that gave him the
best results. But that's not actually the most interesting part
of his discovery. I mean, first he did that, he said,
I'm gonna put these things out in the sun. Then
I'm gonna wrap them in paper to block in a
visible light and see if they make an impact on
the photographic plates. And they did so he thought, oh,
that's cool. But then he accidentally left a bunch of

(24:31):
them in a drawer next to these photographic plates without
shining them in the sun, so he sort of messed
up his experiment. He thought it was necessary to leave
it in in the sun to absorb energy and then it
would give off this radiation, but he accidentally left over
the weekend a bunch of iranium crystals next to one
of these photographic plates and came back the next week

(24:51):
and said, m oops for guys to leave this stuff
in the sun. But let's just develop this film and
see what it says. What seriously, seriously, total accident, total accident.
And he thought, well, you know, I guess I did
this weird experiment where I skipped the step with the sun.
Let's see what happens. And he developed it and the
picture looked exactly the same, which tells him that it

(25:12):
didn't need to absorb energy from the sun. It wasn't
luminescence where it was slurping in energy from the sun
and then changing it into X rays or something. It
was different. The uranium crystals were just giving off energy
on their own. They were just like a source of
some new kind of radiation, some new kind of invisible ray. Right,
that's really what he thought, Right, something invisible is coming

(25:34):
out of this, and this invisible thing somehow had energy. Yeah,
and you didn't have to put in energy. It's not
like with the Crooks too, where you have to apply electricity.
And it generated energy for the electrons which generated the
X rays. And it wasn't like phosphorescence where you have
to sit out in the sun and absorb the energy
and then give it off. It was just like pumping
out this invisible energy. And now we know that it

(25:56):
was alpha radiation and beta radiation, but he didn't know
that at the time, and he just knew he was
admitting some crazy new rays. And then he also won
a Nobel Prize for it, right, he won like the
third one he did, he won the third one, but
just barely. He discovered this, and the day after he
made this discovery he gave a presentation at like the
local scientific society, and he beat out some English physicists

(26:19):
who made the discovery like later that week. What we what?
But if he gave the presentation, then the other one
technically didn't the discovery or I guess he wasn't at
the presentation. He wasn't there yet, because you know the
world was much smaller, so you could give a whole
presentation and a society and friends, and nobody would hear
about it in England until weeks later or so. And
so Sylvanis Thompson made very very similar experiments, very similar

(26:43):
discoveries just a few days later and lost out on
the Nobel Prize because Beckerel made this discovery and was
very quick to report it. Oh, I see Beckrell was
in another country. Yes, this is in France. Interesting. Wow,
that's crazy. Two people in two different countries make the
same fundamental discovery almost a week apart, and there was

(27:03):
no internet. There was no internet. But this is all
spurred by Runkin's discovery of X rays and like cracked
open a whole new area of research. People looking for
these invisible rays. How can we find them, what's making them?
What kinds are out there? And it really did sparkle,
you know, a whole new field of research, all right.
So then that's where we get to Madame Curie and

(27:24):
Pierre Curie and that that this is kind of where
their story starts, right like the year after, Yeah, exactly,
this is where their story starts. So they came in
after Beckarel had already discovered radiation and Runkin had discovered
X rays, and they were really interested in this. And
Curie herself has a really fascinating backstory. Remember it's very
difficult for women in science to have any position and

(27:47):
to have any engagement, to even get an education. She
and her sister, for example, had to take turns working
and going to school. They had this deal where one
of them would work and the other one would go
to school, and then they took turns. And you have
to be really dedicated and sort of fend off all
out of societal pressure even to get to have an education,
not to mention be a scientist at the leading edge

(28:07):
of physics knowledge. Yeah, it's amazing, pretty powerful story. So
she was in France and she I guess she knew
about Beckarel's discovery. She knew about Beckarel's discovery, but most
of the world was more excited about the X rays,
like these new uranium rays that they called them you raise.
People are like, Okay, that's cool, but X rays are
better because they're easier to use, they're faster, they're cheaper

(28:28):
than make sharper images. But she was really interested in
these you rays. She was like, what are these? What's
making them? What does it tell us about the atom
that these things are just being created out of there?
And she was working with her husband, Pierre, and they
had this really cool device, this thing called an electrometer,
and he could basically measure very sensitively how well things

(28:49):
could conduct electricity. And Pierre had developed this technology from
his earlier research, which was into pezo electronics, these little
devices which create electricity if you squeeze them or move
if you apply electrical voltage across them. So we had
this technology and they applied it to the study these
you rays, and they found something pretty cool, which is
that if you have a bunch of uranium, the air

(29:11):
around the uranium tends to get ionized. They can conduct
electricity more easily than if you don't have uranium around
I see. And that was a big clue that it
was maybe giving all some kind of energy. Yeah, that
was a big clue that it was shooting out something
because it was like changing the air, right, This energy
was coming out and it was changing the air around
the uranium. And Pierre and Marie they took like no

(29:34):
safety precautions. They gotta readiated so much in their research.
There are all these moments you can read about in
their lab notebooks where they're like, Pierre has been sick
every single day for the last three months. I wonder
if it's coinciding with all these experiments we've done, whatever,
And they just kept going. It was pretty incredible. They
were really pretty sick during this whole period. Like nine ten,

(29:57):
which is a very intense period of their research, and
discover they're basically sick the whole time. And they never
really associated like all this illness with the research they
were doing. I'm not sure if that was like a
cognitive choice, like let's not influence our research with these
petty details of life, or if they knew and they
just sort of didn't care because it just we're so

(30:18):
hungry to reveal the knowledge. Well, technically, we don't know.
I mean, they could have just been, you know, on
a rash of eating badgers. I suppose so, but you know,
you look at the pattern of damage to their bodies,
like their fingertips had the really terrible damage to them.
You know, Murray Curie, she's now like a hero in France.
Of course, they moved her ashes from wherever they had

(30:39):
been born just about twenty years ago. They moved them
to the Pantheon in Paris, which is where you know,
France inters the ashes and the remains of its most
highly revered citizens. And those ashes were still radioactive. This
is like, you know, seventy years later, Yeah, exactly. She
definitely hurt herself for science, Her legacy lives. She was

(31:01):
really fascinated with this fact that the uranium the U
raise could change the air around them, and this is
what led her to this hypothesis that it wasn't like chemical,
It's not like the electron is giving off some energy
that it's absorbed from some other way. She thought it
was something deep in the atom, that the atoms themselves
or maybe not stable, that there was something changing internally

(31:22):
and it was giving off this energy. And of course
now we know she's right, it was radioactive to Kay,
but this was a really big and sort of bold
idea at the time. Right well, at this point in
our history, we knew about the atom, and we knew
about the kind of structure of it. We knew about
the electron, but we hadn't yet even discovered the nucleus
of the atom. It wasn't ntil Rutherford bombarded gold foil

(31:45):
with radiation later that we understood that there was like
a hard center to the atom that had a nucleus.
God forbid, you know, understanding the proton and the neutron
inside of it. At the time, after J. J. Thompson
discovered the electron, he thought that matter was like a
bunch of electrons floating in a positively charged jelly, and
so we didn't really even understand the structure of the atom.

(32:06):
So this is a really big leap for anybody to make. Yeah,
I mean, she's saying that it comes from deep within
the atom, but we didn't even know there was an atom. Well,
we knew there were atoms, we just didn't really know
like what was going on inside there. We didn't really
understand there was a hard nucleus that was made out
of these smaller particles. So yeah, it's a pretty big leap.
All right, let's get into her actual experiment in which

(32:26):
he discovered this nuclear radiation and what that means and
what other types of radiation were surrounded by. But first
let's take another quick break. All Right, we're talking about

(32:48):
the discovery of radiation, and we're up to Marie Currey
and her discovery that the nuclei of atoms also radiate things,
because we knew about X ray radiation, but we didn't
know about this particular kind which is coming from the nucleus. Yeah,
and we didn't even really know about the nucleus yet.
So this is giving us an inside that there's something

(33:10):
inside the atom, some mechanism which is capable of generating
powerful particle radiation. And so this was discovered originally in uranium, right,
Beckarel saw that it happened. But what the curious did
was that they sort of refined it. They discovered that
uranium itself was radioactive, but that there were variations of
uranium or that was even more radioactive than pure uranium itself,

(33:33):
which suggested that there might be something else in there,
even more radioactive. Oh, I see interesting, Like it's possible
to make an element like an atom the extra radioactive. Yeah, exactly.
They were working with this material called pitch blend, which
is a version of uranium ore, and they discovered that
before you purified it, before you purified it to make
just pure uranium, it was actually more radioactive. So they

(33:57):
had this hypothesis that there was something else in there,
a new element that was even more radioactive than uranium.
So they developed this technique to purify it, and a
lot of the time they spent, a lot of their
actual science was in this process of isolating this bit.
It took them, for example, three years of work on
pitch blend just to isolate a tenth of a gram

(34:20):
of this new substance. That's crazy. I imagine most people
think of radioactive things is like rocks or something, but
for them, this is probably like a powder or something. Right, Yeah,
these are like salts, right. They're grinding them up, they're
purifying that. They're doing chemistry to try to separate the
bits from the other, like does this dissolve in that?
How do we pull this thing apart? So it really
is sort of chemical. And what they discovered is that

(34:42):
there really is something in there that's more radioactive than uranium,
and so they're big discovery was the discovery of a
new element, which Marie called polonium after her native Poland.
I see, because like if you take a uranium atom
and you give it extra protons and new tron's, then
it becomes a different element. Yeah. Actually, uranium breaks down, right,

(35:04):
It splits open, it's unstable, and it turns into other
stuff now we know, into thorium and into radium and
eventually into polonium and all sorts of stuff. So if
you have a bunch of uranium, it eventually turns into
this combination of other elements. It breaks open and turns
into smaller, lighter elements, some of which are more radioactive

(35:24):
than uranium itself. So I guess you could say her
discovery was kind of about nuclear physics, right, even before
we knew there was a nucleus. She sort of maybe
intuited that, you know, there's something going on here inside
of matter and atoms that can somehow, you know, give
off energy and change into different elements. Right, that's maybe

(35:45):
was sort of a big contribution, and not so much
about the radiation, but just kind of about the nature
of the insides of atoms. Yeah, exactly what the radiation
reveals about the structure of atoms and the structure of
matter itself. And you're right, it's totally fascinating to see
one element turned into another element, and if it does
that by giving off a particle, that tells you that

(36:06):
what defines an element must be something related to its
particle content. Right, You're giving off a piece and you
turn into something else. That tells you that peace was
essential for you to be uranium or for you to
be radium. So that was pretty fascinating clue into the
structure of the atom itself yet early nuclear physics. And
so she went on to win the Nobel Prize in

(36:27):
nineteen o three, same year she got her pH d thesis.
Oh my goodness, yeah, pretty awesome. Not only the first
woman to win a Nobel Prize in physics, but the
first woman in France to receive a PhD. Wow, I
wonder which one is more significant in a way. So
she was also in on the third Nobel Prize ever. Yeah,
she and her husband, Pierre and Beckerel all won the

(36:50):
Nobel Prize in nineteen o three. But you know, obviously
she was very deserving, but the initial nomination was only
for Pierre and Bequerel. They excluded her, probably because she
as a woman. But Pierre insisted that, hey, look Marie
has done at least as much work as anybody else.
She's very deserving. So she ended up being included in
the Nobel Prize. Great husband there, yeah exactly. Unfortunately he

(37:12):
died tragically. He was hit by a horse cart filled
with heavy equipment and was crushed one day, no way
after all this, so he was killed by horse radiation
a way exactly. Horses are an energetic particle. I suppose.
Now we shouldn't laugh over anybody's death. It was tragic
and it was very difficult for Marie, but she persevered

(37:33):
and she did a bunch more chemistry and isolated another element, radium,
for which she won the nineteen eleven Nobel Prize, this
time in chemistry. Also, it's rare how many people get
a Nobel Prize for their PhD work. Almost nobody, right,
not very many. There was the guy who got the
Nobel Prize for his pH d work. He discovered the
binary pulsars, which were an excellent test of general relativity.

(37:57):
Fascinating story there is that he did this work as
a p h d student. It wasn't really understood or
appreciated at the time, so he actually left the field
and then won the Nobel Prize and ended up coming
back and getting to do more research. So that's pretty fun.
He was like selling cars and then he gets a
call not quite that far. He was working in the
computing division, I think at Princeton, and then he won

(38:18):
the Nobel Prize and they called him up and they
were like, so, how big an office would you like? Yeah,
it's weird to kind of peak that early in your career, right,
Although Marie kept going. She won a second Nobel Prize,
and even her daughter won one. Two. Yes, her daughter
and her daughter's husband worked together again. On radiation and
they induced artificial radioactivity. They took an element which was

(38:40):
not radioactive, alunium, and then bombarded it with radiation and
they made it radioactive. And so that was a pretty
interesting discovery and they won the Nobel Prize in so
there's a lot of Nobel Prizes in the Curie family.
All Right, Well, then at this point, I guess radiation
is pretty much discovered. I mean, and we sort of

(39:01):
at that point they knew about X rays and then
also about kind of particle radiation coming from the nu kids. Yeah,
and everybody thought that radiation came from stuff, right. We
had found it in oars, from metals deep within the earth,
and so people thought, well, if there's radiation around, it's
coming from the ground beneath us. So people thought if
you went higher up, like higher altitude, the radiation should decrease,

(39:24):
right because you're further away from the Earth and all
these sources of radiation. But people who did measurements found
something really strange. They found it as you went up
to the tops of mountains, the amount of radiation seemed
to be increasing, and that was weird and surprising to people. Right. Yeah,
that's when we discovered cosmic radiation. Yeah, exactly. So there's
this wonderfully hilarious pioneering physicist named Victor Hess. This guy

(39:47):
was born in the castle and his father was a
royal forester to a prince, and he did these amazing
experiments where he went up on a balloon with his
equipment he improved on Pierre's electroscope to measure like ionization
due to radiation, and he went up on balloons. But
you couldn't just like send up the balloon and then
get the data later right like the way we do now,

(40:07):
because there's no way to record this information. So he
actually went on these balloon chips himself, like sometimes up
at night, really high in the atmosphere, a great personal risk.
But he discovered that as you went up higher and higher,
even above mountaintops, the amount of radiation increased dramatically. So
this pointed to something really new and interesting that most
of the radiation that we were feeling around us wasn't

(40:30):
coming from the earth beneath us, but from the skies
above us. I guess once you sort of understand that
there are invisible, you know, things flying around you coming
from the earth, and kind of makes you wonder where
else are these things coming from, or where else can
you find them exactly? And every time you discover a
new way to look at the universe, you are bound
to find something surprising. So discovery of radiation not just

(40:53):
showed us what was inside the atom and helped us
see inside our bodies. It also helped us see the
universe in a new way and to see really really
bright sources of this new kind of information. And most
of it was coming from space, and so that was
a big question mark for decades, like what is making
radiation out in space and shooting it at us? And

(41:13):
that's an area of research still today, Like we understand
a lot of the source of that cosmic radiation now,
but not all of it, right, Yeah, it's a big mystery.
It's like it could be anything. Yeah, at the time,
people really didn't understand. Now we know that a lot
of that radiation comes from the Sun, it's the solar wind,
and also comes from outside our solar system, from the galaxy,
from the black hole at the center of the Milky Way,
for example, emits a lot of radiation, and other crazy

(41:35):
stuff out there emits radiation. But there's still a lots
of this radiation from space that we do not understand.
The very very high energy particles very tip of that
spectrum are higher energy than anything we understand can make.
So radiation is still telling us about the universe and
giving us clues about things out there that we don't
know about. I'm guessing the scientists just wanted a better

(41:55):
view out of his lab. So he's like, I mighta
put it on a balloon. Yeah, I don't know. Or
maybe he needed a break from whatever was going on
in his life and you just need an excuse to
take a flight this castle to watch castle drama. It's
like I'm hopping down my balloon to do signs as
we all do. If they ad made a reality show
about it, that would have been the dramatic ending to
an episode as he floats away in his balloon. All right, Well,

(42:17):
I think that's just a really interesting kind of view
into how we came to see that there are a
lot of things that we can't see, right, because how
else would you know that there's things there if we
can't see them or hear them. Yeah, and this is
a pattern in physics that we keep discovering that their
entire segments of the universe we didn't know anything about

(42:37):
because for a long time they were invisible to us.
The discovery of dark matter, for example, we know that
dark matters out there. It's all around us, it's streaming everywhere.
It contains vast amounts of information about what's going on
in the universe and how it was born and how
it came to be, and we only recently discovered it exists.
And that tells us that there's almost certainly more stuff

(42:58):
going on that we haven't yet to open and we
haven't discovered. That will tell a future physicists crazy things
about the universe that we cannot yet even anticipate. Yeah,
and it kind of also reminds you that physics can
be dangerous, you know, like you're probing the unknown, you're
exposing yourself to things, yet you don't know whether or
not the exist or not, or what they're doing to

(43:18):
your body. Right, that's right. I've eaten a lot of
very dangerous airline food and all of my trips to
the large hage On collider. So yeah, your ashes will
probably glow too, Daniel. All that swift that you're eating,
it's probably radioactive, Yes, fund is probably not good for you.
But it's delicious. Yeah, all right, Well that's a pretty
fascinating trip down science history lane, and I hope it

(43:40):
encourages all of you who are curious about things we
don't understand, things we have not yet unraveled, to follow
up those threads. If you see something you don't understand,
try to figure it out. If something doesn't make sense
to you, ask yourself questions until it does. Because remember
that the history of science is just people being curious,
trying to figure stuff out, and pushing full word on

(44:00):
the envelope of human knowledge. Right, yeah, you two can
win a Nobel prize even if you get kicked out
of high school for drawing cartoons. That's not an exaggeration.
All right, Well, we hope you enjoyed that. Thanks for
joining us, See you next time. Thanks for listening, and

(44:22):
remember that Daniel and Jorge Explain the Universe is a
production of I Heart Radio or more podcast for my
Heart Radio, visit the I Heart Radio Apple Apple Podcasts,
or wherever you listen to your favorite shows.