Episode Transcript
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Speaker 1 (00:07):
Hey, we're here. I want to play a new game
I invented. It's a free association particle physics game. You
might qualified doing need a physics degree? No, no, you
might actually be the most qualified person ever. Really, that's
the first time I hear those words ever. But but
I'm game. How do How does it work? All right?
It goes like this. I say a particle, and then
(00:29):
you describe your mental image. You've been doing this for
a while, translating science into visual art, and so I'm
curious what goes on in the mind of a comic
way Now I say the name of a particle. But
all right, I'm game. Hit hit me. Okay, alright, um, Proton, Proton.
I see the color blue, like a little little sphere
(00:49):
that has a soft blue glow. All right, well, then
let's go to the other side. What about electron? Electron?
I see something kind of jumpy, kind of electric like
it has little like electricity bolts coming out of it.
All right, what about the squiggly on Okay, I see uh,
I see Brian green somehow and being kind of squiggly
(01:10):
and shaky. Alright, well, let me try you and Daniel.
If I say the word quark. What do you see?
You're like grant money. If you say the word quirk.
I think of a bowl filled with glue and these
little particles swimming around inside of it like edible. Yeah,
(01:31):
that's my lunch, basically a bowl of glue. No, because
you know, the quarks are inside of proton. They're held
together by this seeding mass of gluons. This this frothing
foam of gluons, and so I can't think of quarks
except being surrounded by gluons. Hi am or hand make
(02:02):
cartoonists and the creator of PhD comics. Hi. I'm Daniel.
I'm a particle physicist, and I have no idea how
to draw a particle. And speaking of were not having
no idea. We are the co authors of the book
We Have No Idea, A Guide to the Unknown Universe,
and the host of this podcast you're listening to, Daniel
and Jorge Explain the Universe, a production of I Heart Radio.
(02:23):
That's right, our podcast in which we zoom around the
universe and find interesting, weird stuff to think about, to
imagine and try to bring clear images into your mind.
A very strange weird stuff that's happening out there. Yeah,
we talked about not just seeing weird stuff, but we
wonder how can we see all this weird stuff that's
out there in the universe. That's right, because part of
(02:45):
understanding the universe is building in your mind sort of
a mental model, like what's going on in the center
of the sun, how does this really work? And where
is the dark matter? Every time you want to understand something,
in some sense, you're building sort of a mental model
that you want to look at. And we're so, where
do those mental models come from? And how do we
form these images in our heads? And how do we
(03:07):
know they're true? Right? Like, how do we know that
what we imagine is happening is actually happening. That's right,
And this is especially relevant for things that are not
just super duper huge that are out there in the universe,
but things that are super duper tiny, like electrons, like protons.
What do they actually look like? And when I do
particle physics, I think about these things visually. I think
(03:28):
geometrically in my mind to think about the relationship of
these particles. But what do they actually look like? They
look like little little balls, don't they They don't look
like little balls. We know that little balls are just
sort of the mental model we have in our head.
It's part of the sort of analogy we make. We say,
we like to think of this in terms of something
that we know, something we're familiar with, and so it's
(03:50):
very easy to do. But then, of course sometimes these
things don't act like balls, that act like waves, right,
and so then you have to like, what do they
really look like? Can you see them? That's right? And
so on the podcast today, we'll be asking a very
deep question. We'll be asking the question what does an
(04:11):
electron look like? Or can you see an electron or
other small particles? That's right? If you were aunt Man
and you got minsculed down to the quantum realm, what
would that actually look like? You know? Frankly, I was
pretty impressed with the creative visuals in that movie for
the quantum Realm. I thought it was like crazy and
psychotic in this way they sort of evoked the weirdness
(04:34):
of quantum mechanics without trying to be too specific. What
do you think of that? He didn't scoff at their
depiction of an electron or electron clouds and stuff like that.
I will be honest, I was prepared to scoff I
had a scoff all loaded up and ready to deliver.
It was at the tip of your the tip of
your tongue, tip of my scoffer. But I was impressed,
(04:55):
and so I withheld my scoffing. I thought, you know,
what somebody really thought about Somebody must have like talked
to a physic cyst and try to imagine. And I
think there's a lot of real science there in imaging
um scientific ideas. You know, take what a scientist is
describing as a mathematical description of the universe and try
to translate it into human thought. And you know, uh,
(05:16):
there is really a lot of art there, and it's
an important part of science. I mean, if you think
about it, we're all made out of particles and electrons
and quarks and protons, um. But what do these things
actually look like? I mean, we know what they look
like when you stack them together, but if you were
to actually blow them up, or if you're where to
shrink down like ad Man down to that level, what
(05:37):
would what would you see? What would your brain register? Right?
That's the question? Yeah, exactly. And when we do particle physics,
we're seeking to understand the universe at its lowest level,
we're going to take it apart. When what is it
made out of? You know? Is it all the way
down to strings? And when we talk about building the
universe out of these little vibrating strings, everybody gets an
image in their head. Right immediately I think of this
(05:59):
a little loop is sort of like fuzzy little loop
that's shaking around. And so it's very natural, I think,
for humans to think of ideas and mathematical models and
physical explanations in terms of mental images. And so today
we wanted to explore, like, what can we say about
what these things look like? How do you see an
individual particle? Because in the end at particle physics experiments
we're talking about electrons, and me wants as if we
(06:21):
have seen them. So we want to pull back the
curtain and show you what we can see and what
we actually are just imagining. Well, my question when I
see that ant and movie is you know, he shrinks
down to the size of an atom or an electron, Right,
that's kind of what happens in the movie, right, But
how does so what is he made out of at
that level smaller atoms and molecules? Do you know what
(06:43):
I mean, because he still looks like ant man. So
what are his clothes made out of? He's made out
of pin particles, right, that's a great question. Like he
starts out made out of electrons and part of and
other particles, right, and he shrinks down and he's the
size of an electron. But you're right, then have his
electrons got shrunk down to smaller electrons? Like? Does that
(07:04):
make sense? Or maybe he just gotten compressed so he
has the same number of particles but they're you know,
just a shorter distance. Because when he's small, doesn't he's
supposed to have the same strength and the same like
mass and weight as his larger version of himself. Oh,
I see, he's just condensed. Yeah, he's like super dense man.
That's that's what they should have been called. Man. Wait,
(07:27):
but then doesn't he also get big? But he gets big?
If that would be true, then he would be like
super light and fluffy man. Right, I'm not sure that.
I'm not sure the physics is really holding together. They're sorry, aunt, man,
you just ruined the movie for me. Thanks. I have
the feeling you're able to suspend disbelief and enjoy these
movies even if the physics is totally bologny. Am I wrong?
(07:49):
You mean, do I have a scoff ready when I
watch movies? Or do you We've been talking for long
enough that you have a sort of a mental Daniel
in your mind that says, Daniel would think this is crazy.
That's a little bit I have to say, and I'm
not super happy about that. I'm so sorry. I feel
like I have to watch every week with you now.
(08:09):
I wish I could go back in time. Daniel. Well,
the mental Daniel in your head says, that's impossible. Well,
that's actually one of my parenting goals is that my
kids have a little mental version of me in their
head that says, what would my dad say about this decision?
And at that point, you know, I'm sort of done.
I'm not needed anymore. Yeah, it sounds like a great
conversation your kids will have with their therapists later on. Alright,
(08:32):
So that's the question today, is what does the world
look like at the sort of quantum particle level. If
we could see an electron, an individual electron, what will
we see and how could we see it? Right? Yeah, exactly?
And how are we seeing it? Because we we aren't
getting sort of pictures of that in science right now.
(08:53):
And not only are we claiming to say we saw
an electron go this way, and we saw you and
go that way, we're claiming stay ments about the particles
they came from, things like the Higgs boson that last
a very brief moments in time. And so not only
are we claiming to have seen you know, electrons and muans,
which is sort of everyday particles, we're claiming they have
seen weird, exotic stuff. So we'll dig into exactly what
(09:14):
we mean when we say we saw the Higgs boson,
And I guess it's kind of a philosophical question, right,
like can you actually see one of these particles without
touching it or without interacting with it? You can? Can
you really like spy on a higgs boson or spy
and a cork? And would it still get a restraining
order if you there? Now? I think that's one of
the really interesting deep questions is are these things just
(09:38):
mental models, Are these just ideas we have in our
head calculational tools we use to predict future experiments, or
are these things really there? Right? And that's why we
want to see them, because it gives us a sense
that things are really there, right, Um, And you know,
I'm actually an expert in this area. You're a nice
bread being there. I think. I think I'm pretty good
(10:00):
there too, physically at least. No, I'm an expert in
pontificating ignorantly about the philosophy of physics. You're a professional
physical pontificator. No. I was actually given the title of
professor of philosophy. Oh right, right, that's right, that that
you do have as part of your job. That is
one of your job titles. You're a professor in the
(10:21):
philosophy department. Yeah. I just showed up at a bunch
of philosophy seminars for a while, and then eventually somebody said, hey,
who are you. What you're doing coming to all of
our seminars, And then I told him maybe I'm a
particle physicist. I'm interested in the philosophy philosophical imvocations of
the research. And they were like cool, and then they
gave me a joint appointment. Apparently that's all it takes
to become a philosopher. Did they even check your ide
(10:43):
where they're just like, hey, you look, you look kind
of like a physicist. I think I do come in.
I think I do look kind of like a physicist
and maybe a tiny little bit like a philosopher as
I get older and more scruffy physics philosopher, or maybe
I just look look more like a homeless person. I
don't know either one. You're qualified to be a philosophy professor,
(11:03):
or there's some quantum superposition between physicist, philosopher and homeless person.
And I'm going for three, you know, something to aim for? Yeah, well,
if this podcast doesn't work out, I might just be
that's right, if we end up in something everyone else
and get suited out of all our money. But I
was curious what people think about when we talk about
(11:24):
seeing particle and how do we see them? And so
I walked around campus at you See Irvine and I
asked people. I said, how can you see tiny particles?
How do they do that at particle physics experiments? So
those of you listening think about it for a second.
If somebody asked you on the street, how can you
see a particle? What would you answer? Here's what people
had to say. I think we have to use like
(11:44):
lens and stuff to use the light, like Prince principle
of light and princible of the lens, so that we
can use like we can manify the small stuff. This
is bigger in chemistry. You can literally see it through
spectroscopy or like atoms and space micro or atoms like microscopes,
electron microscope. So it depends on the particle size. Well,
(12:07):
electron microscopes, I guess get too pretty small. But beyond that,
I'm not sure. It's you know, they have devices that
can sense tiny particulates in air or gas. It was
a microscope, I hope. I don't know magnifying glass either.
One microscope, very powerful device. I believe they use something
(12:32):
called scintillators, which are kind of like really dense interactive slabs.
All Right, it seems that everyone's pretty much said, how
do you look at small things? The answer most people
gave was a microscope. Yeah, And that's not a terrible
answer because microscopes are good at seeing really small things,
and everybody has that experience, and so I think people
(12:53):
just imagine, like, well, if I have a little toy
microscope at home that I can use to look at
bugs in a lab, that a powerful microscope they can
use to look at individual cells. Surely you can just
make microscopes more and more powerful and see smaller and
smaller things. I think there's just sort of extrapolate bigger, right. Well,
I thought it was funny that the answer to how
do you look at small things is using a device
(13:14):
for looking at small things. Obviously I use my small
things looking at device andator. I mean that's what the
microscope means, right, microscope like looking at small things? Yeah, exactly, exactly. Um,
I think that's pretty common. I mean you could level
a lot of the same criticism at physics. You know,
what is dark matter? It's something that's dark and we
(13:36):
think it has matter, and that's about all we know
about it. So sometimes you just sort of like encapsulate
our ignorance or are to the totality of our knowledge
in a cool sounding name which is totally sketchy and
or genius if you think splash cutting edge science. Exactly.
All right, Well, let's dig into it. Let's talk about
what a microscope is, how it works, and what it
(13:56):
can actually see. What is the limit of microscopy. The
key you seem to understand there is that a microscope
is using light. Right, The way that you usually look
at things is that you use light right, photons hit
your eye then make an image in the back of
your retina. Your brain turns that into however you want
to interpret it. Right, So if you're just looking at
something macroscopic, you know, your hand or a ball or
(14:17):
or whatever, a homeless physics professor or something, then the
image just forms in the back of your eye. Right.
So microscope is just a fancy device to sort of
gather the light from really small things and make that
image on the back of your eye. You basically want
to cut out all the lights coming from other things
in the universe and just have the light that's coming
from the small thing you're trying to look at be
(14:38):
the one that hits your eye exactly. And you have
to remember that the back of your eye has a resolution, right,
has these cones and rods and uses a form an image.
If you have something really small and all of its
photons hit like the same rod or the same cone,
then any detail inside of it is just gonna get lost.
It's just gonna look like a dot, right, like one
pixel in your eye. But if instead you have these
lenses which spread the light out, so this tiny little
(15:01):
thing now forms an image that covers the entire back
of your eye. Then you can tell the difference between
one side of it another of the green parts and
the red parts. Right, So it's about spreading the same
light from this from this tiny thing over a larger
area on your eye so that you can resolve the
differences you can see different parts of it. I thought
it was interesting the way you said that. You basically
have to you're looking at things a light that you
(15:23):
have to bump off of the thing you're trying to
look at, right, like, you have to shadow it with photons,
and then you from the ones that bounce around. That's
how you tell what's there. Yes, exactly right. Remember that
things don't emit light unless they're like, you know, a
light bulb or a sun or whatever. If you're looking
at a sample of something saying you've gathered some you know,
cells from the inside of your mouth, or you picked
(15:44):
up some dirt from the ground and you want to
see it, it's not glowing. The only way you see
it is when it reflects lights. You need a light
source like a light bulb, shoots photons at it, and
then those photons bounce off and come to your eye,
and you know, different things have different colors, and so
they reflect different kinds of lights, and that's why things
look green or blue or whatever. And so regular microscopes
work with light, and they work with lenses, right, like
(16:07):
little pieces of glass that are curved in just the
right way to kind of gather all those photons and
kind of focus in or spread them in the right way. Right, yes, exactly,
and so it's all this reflected light, and then they
spread them out so that the thing you want to
look at occupy sort of the back of your eye,
and and you're looking at just that, and you know
(16:28):
that you can have a pretty weak one, like a
magnifying glass does, that you can have a more powerful one.
My wife has really powerful microscopes in her labs because
she looks at individual cells and tries to look at
individual viruses. And so you might imagine, I can just
build a bigger one and a bigger one, and I
can build one the sides of a football stadium, and
that'll let me see an electron. Right, what's the current
limit for optical microscopes or light based microscopes. The limit
(16:52):
is that light itself sort of has a size. It's
not that photons are particles that you can measure with
a ruler or anything. Remember, photons are sort of wiggles, right.
We think of them as these waves, and the waves
have a wavelength, and the wavelength is like how long
it takes them to wiggle up and then wiggle back down.
And different frequencies of light correspond to different wavelengths, right,
(17:13):
So high frequencies means short wavelengths. High frequency just means
they wiggle more often, right, So they have shorter wavelengths
and longer wavelengths like radio waves have a low frequency.
And the thing is that light has a frequency, right,
And that's sort of like the size of the light.
And you can't really see anything that has a that's
smaller than the wavelength of light that you're using. Um,
(17:37):
I guess my question is why not? I think the
best way to think about it is that you're using
light as a probe. You're like shooting photons at something
and you're seeing how it bounces off, right. And but
instead of light, which is hard to sort of visualized,
imagine you're like poking at it with a stick. Right.
If you had like a really wide stick, then you
wouldn't really be able to tell small differences and stuff.
Whereas if you had a really narrow stick, like with
(17:59):
a real point to it, you can really tell the edge.
Like a record player works. Record player works. This has
a tiny little needle and it goes through the ridges
on the record and tells you, like what those little
bumps are. Imagine if instead of having a tiny needle,
you just use like your finger and you couldn't tell,
like how many little bumps are there. You couldn't get
that information out. So what you need is a small
(18:21):
little probe to bounce off of to see the tiny
little differences so that you see so that the light
is actually affected by the thing that you're trying to
look at, you know what I mean, Like if yes,
and then it's affected only by that because if you
have if your light is too large a wavelength, then
things smaller than that are going to affect the light,
but also the things next to it will, right Like
(18:43):
if the thing you're trying to look at is ten
nimes and your light has five hundred nimes, then the
light's going to bounce off the fifty things fifty nime
things next to each other, and it's gonna give you
sort of an average over those If you want to
see things that are really really small, then you need
a probe that's that size so it doesn't bounce off
it and it's fifty neighbors right, all right, So I
(19:05):
get that you need a really short wave length of
light to look at really small things exactly. I guess
My question is why is that a limitation? Like, couldn't
we just make light smaller and smaller and smaller? Also,
just like super high freuency light, Yes, you can with
visible light the and microscopy, the limit is about two nimes.
And the reason is that above that the light has
(19:25):
such high frequency that it has such high energy that
doesn't bounce off anymore. Instead, it becomes X rays, it
becomes gamma rays, and they just go right through. And
so there's no limit to the energy you can have
of light. But eventually you're just you're building like a
laser and you're just zapping these things instead of you know,
probing them. Oh, I see, at some point you shrink
the wavelength down, but that also increases its energy, and
(19:49):
so they start to ignore the thing you're trying to
look at. Is that kind of what's going on? Yeah,
that's one part of it. The other part of it
is the lenses, right, we need lenses to bend this light.
The ability of lenses to work depends on the frequency
of light, and the higher the frequency, the harder it is.
And so like, there aren't lenses that can bend X
rays or gamma rays very well. And that's the basic
principle of the microscope is you're using this lens to
(20:11):
expand to bend the light to take a small image
and make it large, and you can't really do that
anymore as the light gets very very high frequency. At
some point, the light starts to ignore your lenses, is
what you're saying, Not just the thing you're trying to
look at, but just your ability to like focus them, Yes, exactly,
your ability to focus it and make the image degrades
very quickly as the photons get to very high energy.
(20:33):
Plus now you're shooting deadly radiation at whatever it is.
You mean, it kills the things you're trying to look at. Two. Yeah,
I mean X rays you know, are damaging, ionizing radiation,
and they're great for seeing through things, right, but they're
not great for reflecting off of stuff. But I mean,
if we're trying to look at things that don't really die, right,
like an electron or a proton, or you know, a
(20:54):
small piece of rock. Does it really matter if you're
shooting it with X rays? Man, all particles matter. Well,
you know, we we could do without the neutrinos probably, right,
while the neutrinos lobby is going to be knocking on
your door. Uh no, you're right, and we and we
can do that, right. We can probe individual particles by
(21:14):
shooting X rays at them and shooting gamma rays at them, certainly,
but you know, are you forming an image in that case? Right?
You're shooting individual particles at these particles and they're bouncing off,
but you're not really forming an image in the same way.
It's not really my cross copy anymore because you're not
focusing that image, you know, distorting and focusing that image
to make something that you can visually see. Yeah, you
can use gamma rays and X rays to probe stuff.
(21:37):
Or could you make like special lenses, maybe not made
out of glass that it gets ignored by X rays,
but you know, can you make a special lens made
out of something that X rays don't ignore. They're working
on that, and you know people are doing that for example,
to develop X ray lasers. That's one of the challenges.
But it's very difficult to get any sort of material
that will bend X rays or gamma rays. All right,
So that's that's kind of the limitations of tradition microscopes
(22:01):
that use light. Yeah, exactly, it's down to about two nimes.
It's sort of the smallest thing you can see with
a light based microscope. But of course, um one of
the wonders of particle physics is that we think of
everything and that's a particle also is sort of a wave.
So we can talk about the wavelength of particles like electrons,
and you can ask, oh, could we instead of using light,
(22:23):
instead of bouncing light off of stuff, could we bounce
something else off of it's something with a smaller wavelength.
So people have this idea of decades ago, and they said,
what about electrons. Let's get into that idea of a wavelescope?
Is that how you would call it, maybe electroscope, a
particularscope scope? Somebody copyright that quick Yeah, but first let's
(22:46):
take a quick break. All right. We're talking about microscopes
and probing the smallest things in the universe, and so
we talked about how the optical regular microscopes that we're
(23:10):
all used to from physics in high school have a
limitation of about two d and fifty nanometers. That's the
smallest thing we can see with those, which to me
sounds pretty small, but maybe for particles that's really big. Yeah,
Like you want to see an individual molecule, right, or
you want to look at some complicated thing and see
like what, how do the bonds work? Right? You want
(23:31):
to zoom down and look at a single hydrogen atom, right,
They're much smaller than two And so of course I
want to see things that are released some all. I'm
a particle physicist. I want to be aunt Man and
zoomed down to the quantum realm and see how the
universe works. And so I'm definitely interested in ultra microscopy. Right.
And so instead of using light, something else that we
can do is we can use and use electrons to
(23:53):
see something. And so the idea behind using electrons is
that just like when you use light, Right, when you
use light for a microscope, you shine a light bulb
on something and then you're looking at the light that
comes off of it to make your image. It's the
same with electrons. We shoot a beam of electrons it's something,
and then we see how the electrons bounce off, and
then we use that to reconstruct an image. It's not
(24:14):
a direct image. It's not like the electrons hit your
eye and then make an image in your eye. They
go into a computer and the computer says, Okay, this
electron bounced off at that angle, which means is something
here that looks like that these electrons were there bounced
off that angle and sort of sort of uses it
to reconstruct, um, what the electrons must have bounced off of. Okay,
So the idea is that electrons are smaller than photons.
(24:37):
Is that is that the idea? Or you can get
an electron to have a smaller wavelength than a photon. Yes, exactly.
Electrons can have smaller wavelength than photons because they have
um they have more mass and so that ends up
giving them a smaller wavelength. Oh I see, and also
they don't kill the thing you're trying to look at, right,
that's kind of part of the idea. That's right. And
(24:58):
there's actually different kinds of elect on microscopes. There's the
ones with the electrons go bounce off of it, which
is very similar to light based microscopes. There's also other
electron microscopes with electrons do go through the material, the
transmission electron microscopes, but the basic idea is the same,
is that the wavelength of the electron is small enough
that you're sensitive to tiny features. Right. It's it's the
(25:20):
tip of that stick that you're using to sort of
drag across the surface of something to see like where
are the bumps, And then you you have to catch
the electrons and kind of tell what's happening to them. Yes,
you have to catch the electrons or you have no
idea what happened to them, right, So you need like
a little particle beam. You shoot electrons at something and
then you have to catch the electrons, and from the
angle of the electrons you can tell what happened. It's
(25:42):
sort of like, you know, imagine that you're in the
dark and you're I don't know, and there's a wall
in front of you. You want to know what the
shape of it is, so you throw tennis balls at it, right,
and if the tennis balls are dark, tennis balls obviously
exactly glow with electrons. Um. Yeah, I carry I carry
glow that our tennis balls with me at all times,
just in case I end up in this situation, just
(26:04):
in case there there's a power outage. To throw tennis
balls to the wall and if they bounce up, you
know that the wall has a certain angle to it.
And if they bounce right, then you know the wall
has a certain angle to it, and you know, and
if it says out the exactly your wife, then you
found your kids, you know. And if you're really careful
about it, and you're throwing these tennis balls at different
parts of the wall and measuring the angles they bounce out,
(26:24):
then you can build a mental image of what the
wall looks like without seeing using light. Right, that's exactly
the idea. And you know, the smaller the ball that
you throw the wall, the more you can resolve really
small features on the wall. And that's why we want
to use small wavelengths. But you have to be really
good at throwing these tennis balls right and measuring where
they're going, yes, exactly. You have to be very accurate
(26:48):
about shooting them, and you have to be very good
at catching them, and then you need a computer to
put that all together and to make an image for
your brain and it's pretty cool because we've been able
to look at single molecules right with these electrons on microscopes. Yeah, exactly.
In two thousand nine, they made an image of a
single molecule. And when I first saw that, I thought, wow,
(27:08):
Like I've had an image in my head of what
a molecule looks like. You know, it's got a bunch
of particles zooming around whatever. But here's like a picture.
You know. It's like you think you know what Saturn
looks like. And then we fly a probe by and
you get actual pictures from Saturn. Right, that's much more satisfying.
And to see like a picture of an atom than
your imagination, yes, exactly, to go from imagination to reality.
(27:29):
That's a transformational moment in science. And so that's what
did it look like? Um? Did it look like? Paul Rudd?
There was some would be a shocker. It looks like
a man, Oh my god, he's been here. Yeah, and
he wrote s os right helped me. Finally somebody can
see me. I'm stuck down here. I'm slack down here
with Michelle Peiffer. Go away. Actually I'm fine. Um no,
(27:53):
it looks sort of like what you would imagine, you know,
you can see the electrons orbiting the nucleus, but you
can see that stuff is there. You know, it gives
you the idea that it's real, that it's not just
a mental calculation. That's it's pretty fascinating. And then a
few years later they were able to image a single
hydrogen atom. Right, that's just a proton with an electron
around it. It um It's pretty impressive. And these days
(28:14):
electron microscopes can get you down to half of a
N animator. So light based microscopes are two animators. Electron
microscopes down to half a N animator, So that's a
big difference. To mean, that's kind of weird because it's
kind of like you're saying, hey, I saw this glue
in the dark tennis ball that was sitting there, and
then I asked you, how do you know it was there?
And then you say, well, I throw a bunch of
(28:34):
glue in the dark tennis balls at it, and that's
how I know there is a glue in the dark
tennis ball there. Do you know what I mean? Isn't
that weird? It is kind of weird, and if you
want to be really strict about it, philosophically, then yeah,
you're not really seeing it. You're inferring its existence from
you know, probing it, and you're building a mental model. Right.
(28:55):
But that's sort of the same with everything, Like how
do you know that there's a watermelon in front of you?
You're like, oh, I see it? Well do you see it?
Or do you see the photon that bounced off of it?
And then your brain built a mental model in the end,
it's really the same. Oh I see you're saying that
the watermelon itself didn't hit your eyeball hopefully not hopefully
(29:16):
notice you know, looking in the dark with the watermelon
throwing it around. Uh, you never see the thing you're
trying to see, you know. I mean like you never
directly touch the thing that you're trying to see. You
just touched things that touched it. Yeah, So you can
either say you never really see anything, or you can
say that's what seeing is, right, interacting with the universe
(29:37):
and building a mental model of what you think is
out there. And so from that perspective, seeing with light
and seeing with electrons it's really the same. I mean,
it's maybe more layers of indirection, but they're both indirect
at the same level. Well, you know what my grandmother
always used to say, I'm prepared for some Joree grandma
wisdom hit me. So he said, you know that seeing
(29:58):
is believing that seeing can be whatever you define it
to be. Yeah, exactly. And I think that seeing plays
a big role in making people believe something because it's
it's such an overwhelming amount of data. It really affects
the way you think about things. It's it's such a
dramatically important part of how we build this model of
where we are in the universe. And so I think
(30:19):
a lot of people don't believe something unless they can
see it. For example, I was listening to the Bologny
documentary on Netflix about Bob Lazarre and UFOs, and like,
he claims to have seen these things, but if I
don't see them, I can't believe what he's saying. It
has to be repeatable, right, like checkable. Yeah, Well, especially
for something really crazy, like I found an alien spacecraft.
(30:42):
It uses anti gravity propulsion. You know, extraordinary claims require
extraordinary evidence. And you know I wouldn't believe those claims
from Stephen Hawking if I couldn't see the ship myself.
So I'm certainly I canna believe it from some random dude. Well,
all right, so that's electron microscopes. We can shoot electrons
and things and by measure aring how they get deflected
or bounce back, then you can look at some pretty
(31:05):
small things because electrons are smaller than light. That's the
idea where you can get electrons down smaller too, smaller
sizes and exactly. Okay, so now we get into the
weirder stuff, right, like, how can we see an electron itself? Right?
How can we see the tennis balls themselves? So how
do we know what the tennis balls actually look like?
But first let's take another quick break. All right, So now, Daniel,
(31:41):
how do we see an electron? Because we our best
technology sort of is in microscope, is to use electrons
to look at things. But how can we see something
as small as an electron itself? Yeah? That's really tricky,
and I think the most honest answer is that you
can't really. If you could somehow isolate one electron in
trap and you could balance electrons off of it so
(32:02):
you could tell that it was there, but you know,
you can't really use tennis balls to see tennis balls.
I mean, you can tell that it's it's there, but
you can't like see it to resolve features that are
that are smaller than it. Right, you want to know
more than it was there. You want to see, you know,
what does this side of it look like? What does
that side of it look like? And so you can't
do that with this. It looks like Paul Rudd also
(32:25):
exactly is it getting wrinkles or is it getting botox?
You know, um, what are the features of it? So
you can't use an electron to see an electron in
any detail? Can you use something smaller? Can you like,
can we shoot quarks at it? Are quark smaller than electrons?
Or you know, little strings? Can we shoot little strings
at it? All these particles are microscopic. They're basically point particles.
(32:45):
What we can do is we can shoot other particles
at them, but we can't really resolve any features. You know,
you could shoot super high energy particles at them, and
you can try to get a sense for like where
is the charge distribution, But you're not really going to
get a satisfying image out of these things. And in
the end, all you can do is really detect that
it's there. So I don't think you can see and
you can resolve any features. All you can do is
(33:07):
make a statement about its existence. Oh, I see, we
can't touch it, or we can't poke at it the
same way that we poke at other things because we
don't have anything to poke it with. That's right. And
if you poked it with another electron, with another particle,
all you would do is say that it's there. You
can't really see anything smaller than that particle. It could
be that there's things inside the electron. Right, imagine that
(33:28):
the electron is not fundamental, it's not a point particle,
but it's made of smaller particles. Okay, how would you
tell s? Quickly? On? Yes, quickly? On exactly? How would
you tell what? You would have to take super duper
high energy particles and shoot them at the electron and
then try to see like a variation in the response,
Like if I shoot them at the top of the
electron or the middle of the electron or this part
(33:50):
of electron, do I get different responses? And this is
for example, how we discovered that the atom has a nucleus. Right,
we shot high energy particles at gold atom and we saw, Oh,
if you go right in the center, boom, they bounce back,
and if you miss the center, then they don't bounce back,
so we could tell if there was something there in
the center. So what you need for that is really
really high energy particles, so they have really short wavelengths,
(34:13):
and we've done that kind of stuff. We shot really
high energy electrons at each other um and we've never
seen anything inside the electron. So as far as we
can tell, we haven't been able to resolve any features
inside the electron, not yet. At least. It's like taking
a little box and shaking it to try to figure
out what's inside of it, but you can't open the box. Yeah, yeah,
exactly exactly. And so all we need is, you know,
(34:34):
a hundred billion dollars to build a really big accelerator
so we can shoot these things at each other with
even more energy and maybe start to figure out where
the stuff is inside the electron. Oh man, Daniel, is
this what this has all been about? You're just trying
to ask me for money. Just take out your check
book and write a bunch of zeros. I mean, how
(34:54):
hard is it? Sure it's easy, I'll do it here,
hold on, I don't never the check will go through.
But I can definitely write you a check. You might
have to wait to cash it, but here you go.
That's right, I don't have the cash flow right now.
But and in the end, that's what we're doing with
particle colliders, is that we're just shooting higher and higher
energy particles at each other to try to see inside them.
(35:16):
And that's how we found out what's inside the proton. Right.
We saw that if you shoot the protons at each
other with that high enough energy, or actually if you
shoot high energy electrons at protons, then sometimes they bounce
back with a lot of energy and sometimes they go through.
And that's how we found that there were quarks inside
the protons. We could see these little spots inside the
(35:36):
protons where the electrons are more likely to bounce off
and interact. So that's how we discovered quarks from the
way that it behaves when you shooted it, not from
what you measure of the things that you shoot at it,
which is how it's sort of like what happens if
I shoot at it and some weird things happen, and
from that you can tell what was inside the box. Yeah,
we shoot like super duper tiny high energy tennis balls
(35:59):
at these protons and sometimes they bounce back and sometimes
they go through, and that tells us you know, where
the stuff is inside the proton, and that sort of
gives us an image. Is sort of like X raying
the proton. I guess you could say, so, does that
mean that we can exceed the limit of half a
nanometer that you mentioned before as being the limit that's
the limit for electron microscopy for like seeing samples. But
(36:20):
if you use particle colliders, then yeah, you can get
smaller than that. But you know, it's it's not as
clear that you're seeing. I mean, you're not like you
can't take an individual proton and scan it and send
a bunch of electrons at it. Right, this is a
one off experiment, one electron against one proton, and then
you do it again and you build up a sort
of statistical model for what's going on inside the proton.
(36:42):
But you can't take one proton and like, you know,
zoom a bunch of electrons at it and get an
image of it in the same way that you can,
for example, a hydrogen atom or molecule. Oh, I see,
you can't look like if I had a special electron
that I wanted to look at that, that would be impossible. Yeah,
you basically just get one look. But you can sort
look at electrons in general to maybe see what's inside
(37:04):
a whole bunch of them. But like if I gave
you a special electron, said hey, this electron came from Mars,
can you check it out? You would not be able
to tell me anything about it. I could, you know,
probe it once. Basically, it's sort of like it's a
destructive technique. Here's this really special electron, Daniel, do you
tell me what it looks like? Sure, it looks like this.
(37:25):
Where is it? I'd be like, well, first sign this waiver,
you know, yeah, I promise you won't sue me. Yeah, exactly. Um,
But you know, there are lots of things that we
started at the large hage On collider that we can't
see directly, and yet we claim they exist. So maybe
before we wrap up we should dig into that a
little bit. All of this has been kind of seeing
(37:48):
things that we already know about. But you guys had
the collider are trying to look for things that you
don't even know what they look like. If you could
even look at them, that's right, And to make it
even crazier these particles is that we think exist, they
don't last very long. So for example, every time we
make a Higgs boson, it lives a very brief, happy
life for about ten to the minus twenty three seconds, right,
(38:11):
So these things, it's not like we make a pile
of Higgs bosons and then they have a bowl of
them and we're like, okay, what are these things? Like?
Each one lives for just the briefest, briefest moment. Not
only do you not know what they look like, but
they barely exist at all exactly. And what happens is
they exist briefly and then they turn into other particles,
particles that were familiar with photons or electrons or muans
(38:32):
or something. And then we have a big camera essentially
that tracks the passage to those particles, like we these
electrons or muans or whatever. As they fly out from
the point of the collision, they leave these little traces
in our detectors, in little scintillators or trackers or calorimeters,
are all sorts of stuff. They give us a clue
about the direction that these particles came out of. So
(38:53):
we don't see the Higgs boson itself. We just see
the particles it turned into. And even those we don't
see those particles themselves. We see we see sort of
the trace they left in our detectors. You know that
they were there, but you don't actually know what they
look like. Like the Higgs boson could look like Paul Rodd,
which just would never know, that's right. Um, we can
just see the sort of their footprints, and so it's
(39:14):
sort of like I don't know, arriving at like a
big fight scene and you see like footprints running off
in every direction, and then you try to imagine, like
what happened. You know, somebody ran away this way and
this blood stains this direction, someone fighting with Kenna Reeves
and it was Jorge versus Paul. What happened? But we
can use that to tell like, oh, this was an
(39:34):
electron and had this energy, and that was a muan
had this energy in this direction, and we can use
that with a bunch of physics arguments to reconstruct what
we think happened in the collision and whether or not
a Higgs boson existed briefly. And so in the end,
it's all sort of indirect and it's all statistical and
We have no idea what a Higgs boson looks like,
but we're pretty sure it was there just to maybe
(39:55):
recap here and start to wrap up. We it seems
like we kind of have a like a progression, right Like,
if you want to see things with your actual eyeballs,
the limit of that is about two hundred and fifty nanometers,
right Like, if you use lenses and optical microscopes, and
if you want to actually want to see the photons
hit your eyeball, that's about the limit, right, yeah, exactly.
(40:16):
But if you want to be a little bit more indirect,
you can use electron mics with microscopes and you don't
actually see the electrons, but you maybe see the image
that comes from the electrons hitting some sort of sensor,
And that one gets you down to about half an animeter.
And then if you want to spend a couple of
billion dollars and be more sort of removed from the
(40:37):
thing you're looking at, then you have to get into
particle colliders and and those maybe you don't have a limit.
There's no limit except for money. Right. You can build
a particle collider the size of the Solar system and
see things down to like ten to the minus twenty
ten of the minus twenty five um. As far as
we know, there's no limit until you get to like
the plank length, like what we think is the smallest
(40:58):
spatial resolution of the universe itself. But that would require
like jillions of dollars a very special microscope. That's right,
And so everybody, get get at your checkbooks and support science.
No just kidding, Tell your congress people or your members
of government that all this stuff is worth the money
because we want to know what the universe looks like.
We want to tear it apart at the smallest scale
(41:19):
and build an image in our minds of what's going on.
Just focus on all those tax dollars and making into science.
That's right, alright, So thanks for tuning in everyone. That's
the answer to the question can you see an electron?
And what's the smallest thing that we can see? And
does it look like Paul Rudd? Now we know that
(41:39):
we may never know possibly, all right, Well, thanks for
tuning in. We hope you enjoyed that and hope you
got some clarity into seeing things at the very smallest
of levels. See you next time if you still have
a question after listening to all these explanations. Please drop
(42:02):
us a line. We'd love to hear from you. You
can find us at Facebook, Twitter, and Instagram at Daniel
and Jorge That's one Word, or email us at Feedback
at Daniel and Jorge dot com. Thanks for listening, and
remember that Daniel and Jorge Explain the Universe is a
production of I Heart Radio from More podcast from my
heart Radio, visit the i heart Radio app, Apple Podcasts,
(42:25):
or wherever you listen to your favorite shows.