Speaker 1: Hey, Orne, Hey, do you have a lot of cousins
Speaker 1: in your family? Yeah, I've got a few. I have
Speaker 1: maybe over thirty six cousins, maybeing around the number. Wow,
Speaker 1: that's a big family. Well, would you be surprised to discover,
Speaker 1: sort of late in life, a brand new cousin you'd
Speaker 1: never even heard of before? That would be pretty amazing,
Speaker 1: kind of weird, I guess, but maybe yeah, I would
Speaker 1: be surprised, all right. And then what if that cousin
Speaker 1: turns out to be exactly like you, like, look like
Speaker 1: you in every single way. Okay, Yeah, that's that's getting
Speaker 1: kind of weird, all right. And then what if this
Speaker 1: cousin looks exactly like you? Accept there are two hundred
Speaker 1: times more massive Dan, Hi, I'm Poor. Hey, I'm a
Speaker 1: cartoonist and the creator of PhD comics. Hi I'm Daniel.
Speaker 1: I'm a particle physicist, and I do not have thirty
Speaker 1: six cousins. Welcome to our podcast, Daniel and Jorge Explore
Speaker 1: your Family Tree, in which we examine all the amazing
Speaker 1: and fascinating things about the universe, about the big things,
Speaker 1: the small things, and about how things are related to
Speaker 1: each other. Yeah. So, um no, that's not the name
Speaker 1: of our podcast. It's actually Daniel and Jorge explain the
Speaker 1: university production of My Heart Radio, in which we do
Speaker 1: examine crazy things about the universe and we try to
Speaker 1: make them relatable. We try to present them in a
Speaker 1: way that you can understand them, so they connect to
Speaker 1: topics that matter to you. Yeah, in a way, we
Speaker 1: do sort of explore the family tree of the universe.
Speaker 1: You know, how you came to be here, what what
Speaker 1: sort of pairings and fusions occurred for you to be
Speaker 1: here in this universe appreciating it and listening to funny podcasts.
Speaker 1: H I think one of the reasons people are interested
Speaker 1: in the origins of the universe and the creations of
Speaker 1: our cosmos is because they want to understand how we
Speaker 1: got here and what it means in the same way
Speaker 1: people explore their family tree. They want to know where
Speaker 1: did my family come from, what stories are in our past,
Speaker 1: what is my personal context? And also I think it's
Speaker 1: a useful way for us to sort of organize our thoughts.
Speaker 1: You know, when we think about the the universe in
Speaker 1: terms of particles, we sometimes think about how those particles
Speaker 1: are related to each other, Like, do particles have families. Yeah,
Speaker 1: and I think you know, every part of anyone's family
Speaker 1: tree or origin tree kind of tells you a little
Speaker 1: bit of the story of the of the whole thing, right,
Speaker 1: like how you came to be, how things work, and
Speaker 1: how things move about in life, and other ways your
Speaker 1: life could have gone. Like if you have a very
Speaker 1: successful cousin that's a gazillionaire, then you know, you wonder
Speaker 1: could I have made different choices and been a gazillionaire?
Speaker 1: Or if be people's paths in life diverge. Yeah, or
Speaker 1: if you are that busile in our cousin, then good
Speaker 1: for you. Please please contact us. We would love to
Speaker 1: take your donations. That's right. It would be awesome to
Speaker 1: have at least one gazillionaire listener. Who is our richest listener?
Speaker 1: That's a good question. Pod. You have to send us
Speaker 1: a check. Whoever sends it is the biggest check that
Speaker 1: doesn't bounce. When's this little plaque here that I am
Speaker 1: just now putting together. It's made of platinum? Right, Yeah,
Speaker 1: well it's going to be once we get those checks. Yes,
Speaker 1: you'll get a drawing of a plaque that's made of platinum.
Speaker 1: Oh my gosh. Even more valuable from a well known
Speaker 1: internet cartoonist exactly. But we do try to understand the
Speaker 1: world around us, and sometimes that means putting things in
Speaker 1: context and understanding what are the patterns, what are the
Speaker 1: structures there, and what clues do those patterns give us
Speaker 1: about that sort of fundamental nature of the universe. Yeah,
Speaker 1: so to be on the podcast, we'll be talking about
Speaker 1: a particle in nature that is maybe not the most
Speaker 1: famous one um and maybe not the most well known
Speaker 1: one or consequential in your existence, but which does I
Speaker 1: think tell you a little bit about and told humanity
Speaker 1: a little bit about how the universe works. Yeah, this
Speaker 1: is the non gazillionaire cousin. This is the cousin that
Speaker 1: ended up maybe sleeping under the overpast and wearing funny
Speaker 1: clothes to the family reunion. I feel bad for this particle. Now,
Speaker 1: this particle doesn't need your help. It's very massive. Yes,
Speaker 1: So in today's episode, we'll be talking about the muan electrons, mysterious,
Speaker 1: lesser known, much more massive cousin. And I'm biased, of
Speaker 1: course because I'm a particle physicist, but I think it's
Speaker 1: really fascinating to think about how we know each particle
Speaker 1: is there. We talk about the standard model of particle
Speaker 1: physics sometimes, but that's a theoretical construct. It's like our
Speaker 1: idea for how these particles might relate to each other.
Speaker 1: And that's fascinating. We'll dig into all that, but I
Speaker 1: think it's also really important. Remember each of these were discovered.
Speaker 1: There's a story behind each particle. Humanity didn't know it
Speaker 1: existed and then boom, some experiment revealed it. And on
Speaker 1: the podcast, we've talked about the first discovery of the particle,
Speaker 1: how the whole concept of a particle was created, the electron.
Speaker 1: Then we talked about how we know the photon is
Speaker 1: a thing, how we know it's really a particle, the
Speaker 1: photo electric effect, And so now we're gonna take the
Speaker 1: next step and talk about the discovery of the muan. Yeah,
Speaker 1: because you know, I think that every particle tells a story,
Speaker 1: you know, and also every story is made out of particle.
Speaker 1: So there's kind of this really weird, confusing loop there
Speaker 1: that honestly, Yeah, this is like the Superhero Origin story
Speaker 1: particle version. Yeah. So the muan is not a name
Speaker 1: that rolls off the tongue. Makes me think of maybe cows,
Speaker 1: mu muans, maybe uan Muan, Muan mu Off, muanmu Off.
Speaker 1: I was thinking sort about karate kid thing there, but
Speaker 1: it's back to the eighties reference. Yeah, back to the
Speaker 1: age differences. And it's it's funny actually because the name
Speaker 1: Uan is totally inappropriate. We'll dig into it later. But
Speaker 1: they named it before they discovered it because they thought
Speaker 1: it was going to be a different particle, and then
Speaker 1: they sort of changed the name later. Um, it's not
Speaker 1: a great history for naming particles. Boy, my favorite topic
Speaker 1: in science. Yeah, and so I was wondering, how much
Speaker 1: do people know about me once? Is it a famous
Speaker 1: particle or is it sort of the darker cousin of
Speaker 1: the electron that nobody really knows about, hasn't gotten the
Speaker 1: same Instagram attention the black Sheep, the gotee wearing particle
Speaker 1: of the family tree. Now you're setting enough to be
Speaker 1: like the grumpy particle. It's going to come in with
Speaker 1: some evil plan to finally get It's it's revenge, and
Speaker 1: it's you already made this particle, the homeless particle that
Speaker 1: lives under a bridge. So yeah, that was the sad
Speaker 1: particle that deserves our love and compassion, not the one
Speaker 1: that's been plotting its victorious return to the center of attention. Well,
Speaker 1: you never know what these particles, you know, physics, there's
Speaker 1: a lot of drama. But as usual, I walked around
Speaker 1: and I asked people if they knew what the muan
Speaker 1: was and how we knew it was a thing. Yeah,
Speaker 1: So before you listen to these answers, think about it
Speaker 1: for a second. If someone asked you what a mu
Speaker 1: on is, would you know what it is? Have you
Speaker 1: heard it before? Here's what people had to say. I'd
Speaker 1: say it's a unit of measure. It's like one of
Speaker 1: the fundamental elements or particle of what makes up everything.
Speaker 1: Mu one. I believe this to be the name of
Speaker 1: a sub atomic particle uh luans luans uh. I don't
Speaker 1: remember what classification they follow under as far as the
Speaker 1: naming conventions. Fundamental particle, some sort. It's real small subotomic particles.
Speaker 1: I kind of represented what it does. How do we
Speaker 1: know nuance exist um particle starts. So what's your opinion
Speaker 1: of these answers today? Good? It sounds like most people
Speaker 1: have heard of it or I heard of the word before.
Speaker 1: You know, very only a few people said never heard
Speaker 1: of it or think it was a unit of measure,
Speaker 1: like a you know how much water? Would you like,
Speaker 1: I'll have seven muans of water. I wonder that if
Speaker 1: you pronounced it correctly, maybe they knew about it, but
Speaker 1: just under a different pronunciation. Do you think I'm mispronouncing
Speaker 1: the name of mu. I don't know. I mean, what's
Speaker 1: the correct way? Is it muan or muan? Like you're
Speaker 1: making it sound like a Disney movie, like, oh, my
Speaker 1: favorite Disney princess is mulan. My favorite Disney princess muan muan. Oh.
Speaker 1: That is a great way, though, to get more attention
Speaker 1: for particles in the mainstream. We should get Disney to
Speaker 1: name the next Disney Princess after a particle. Why not that?
Speaker 1: Why it could be the next Pixure movie. What it's like?
Speaker 1: What's the emotional roller coaster right of being a fundamental
Speaker 1: particle of nature? Yeah? So much to explore there, and
Speaker 1: I expect that will be getting checks from Pixar when
Speaker 1: they make a billion dollar movie out of it. But
Speaker 1: I was impressed with these answers, though, I want to
Speaker 1: pick a bone about one thing. People say, yes, it's
Speaker 1: a fundamental particle, totally cool. People also say it's a
Speaker 1: sub atomic particle or it's one of the fundamental particles
Speaker 1: that make up everything. And that's really a key idea
Speaker 1: that I think people have not understood about muans, that
Speaker 1: you can be a tiny particle and not be sub atomic,
Speaker 1: not be part of the atom. Oh, I see, subotomic
Speaker 1: doesn't just mean it's smaller than atom. You're saying that,
Speaker 1: it means that you're part of the atom. Remember, fundamental
Speaker 1: particles have no size, their dots, they're zero volumes, so
Speaker 1: they're all smaller than the atom. In that sense of
Speaker 1: being fundamental guarantees you'd be smaller than the atom. I
Speaker 1: think to me, sub atomic means it's part of the atom,
Speaker 1: like you break it up and you find it inside
Speaker 1: the atom. Okay, so we'll get into that, but let's
Speaker 1: bring it down for people. For us, what is a
Speaker 1: muan and why does it sound like an electron? You
Speaker 1: it ends with O N, but maybe, but it's not
Speaker 1: the electron. Yeah, but it really is related to the electron.
Speaker 1: It's sort of like the electrons cousin. And by that
Speaker 1: I mean that it's identical to the electron in so
Speaker 1: many ways. It has the same electric charge, it has
Speaker 1: the same interactions with matter like it interacts via the
Speaker 1: weak force and via the electromagnetic force, but it doesn't
Speaker 1: feel the strong force, just like the electron. It has
Speaker 1: a neutrino, just like the electron has its neutrino. So
Speaker 1: in so many ways, it's exactly the same as the electron.
Speaker 1: Sound like when you discover a new particle and it's
Speaker 1: totally different, like a cork or a gluon, it's just
Speaker 1: completely different from the electron. This one is very very
Speaker 1: similar to the electron. It's like weirdly similar, but then
Speaker 1: with one important difference. Okay, so it's a particles. It's
Speaker 1: not a cow, it's not a Disney princess. So it's
Speaker 1: a particle, meaning like it's a it's one of these
Speaker 1: things that you see nature in the universe, like things
Speaker 1: that pop up and you can touch them and and
Speaker 1: there it's a thing. Yes, muans are a thing. There
Speaker 1: are a little thing. There are particles, and there are
Speaker 1: little dots of matter. They have mass and they have
Speaker 1: charge and they interact. Okay, so it's it's a particle
Speaker 1: like the electron. But you're saying and you say it's
Speaker 1: a cousin of the electron, not that they share like
Speaker 1: not that their parents were siblings, but just like in
Speaker 1: the sense that it's very similar to the electron. Yeah,
Speaker 1: when we organize our knowledge, we look for patterns. We
Speaker 1: look for similarities. Right like when we were a hundred
Speaker 1: years ago, when the state of knowledge about the universe
Speaker 1: was the periodic table. We didn't just have like a
Speaker 1: pile of different elements and say here's an element. There's
Speaker 1: an element. We said, oh, look, this one is similar
Speaker 1: to that one. They're both really active, or these are
Speaker 1: really similar because they're both really inactive, or this one
Speaker 1: weighs a tiny bit more than that one. We notice patterns.
Speaker 1: We put those patterns together in the same way we're
Speaker 1: looking for patterns in the fundamental particles. So we try
Speaker 1: to figure out which ones are related to each other.
Speaker 1: And we have only a few handles on each particle.
Speaker 1: Is only like a few things we can know about
Speaker 1: a particle, right, And so is this a particle that
Speaker 1: we can see in our everyday lives, like is it
Speaker 1: floating around? Does it move around wires and electricity like
Speaker 1: the electron, or is this kind of a weird one
Speaker 1: of those weird particles And you know you don't ever
Speaker 1: actually see Yeah, you don't see the muan because it
Speaker 1: doesn't last for very long. It lives for two point
Speaker 1: two microseconds and then it turns into an electron and
Speaker 1: some neutrinos. But they are actually everywhere. There's ten thousand
Speaker 1: muons going through a square meter of Earth every minute,
Speaker 1: so there's a lots of muans everywhere, but you just
Speaker 1: can't really see them very easily because they don't last
Speaker 1: very long. Wait, what I mean? How can they be
Speaker 1: everywhere but also only last two point to microseconds? Does
Speaker 1: that mean that they're they're constantly coming into existence, lasting
Speaker 1: for two point two microseconds and then disappearing and breaking up,
Speaker 1: or what does that mean? How can they be all
Speaker 1: around is but also evaporating at the same time. Well,
Speaker 1: there's two things going on there. One is your right,
Speaker 1: they're being created um when particles hit the atmosphere. So
Speaker 1: protons hit the atmosphere and they create a shower of particles,
Speaker 1: some which include muans, and those muans fly along a
Speaker 1: little bit, but they don't last very long, just two
Speaker 1: point two microseconds, and then they turn into electrons. But
Speaker 1: they last for two point two microseconds according to their
Speaker 1: clocks because they move really fast. There's a relativistic time dilation.
Speaker 1: So the according to us that two point two microseconds
Speaker 1: takes longer to click, and so for us it can
Speaker 1: take like seconds or minutes from muans to decay. But
Speaker 1: for them, if you're sitting on top of the muan,
Speaker 1: it would only last You would only be alive for
Speaker 1: two point two microseconds. Yeah, that's the half life of
Speaker 1: a muan. So muon is not stable. It's not like
Speaker 1: an electron you can just sit there for eons and
Speaker 1: eons and just be itself. A muon is a heavy particle,
Speaker 1: and heavy particles like to decay into lighter particles. In
Speaker 1: this case, the muon turns into an electron very quickly
Speaker 1: according to its clock. Oh, I see the ones that
Speaker 1: we see. The ones coming from the atmosphere are moving fast,
Speaker 1: so they last longer. But if I just created a
Speaker 1: mew on here in front of me, it would last
Speaker 1: only for two point two micro seconds, and it's not
Speaker 1: going anywhere. If you could bake muans in your oven
Speaker 1: and you take them out of the oven two point
Speaker 1: two microseconds later, boom, they turn into a electro. Yeah,
Speaker 1: you gotta eat them up real quick. Exactly. They're like
Speaker 1: making fortune cookies or toss them really fast, have him
Speaker 1: pop out of the toaster really fast, in which case
Speaker 1: they would last longer technically, right, that's true. Yeah, exactly.
Speaker 1: Somebody could shoot muans into your mouth and it would
Speaker 1: last long enough to get there. I wouldn't recommend that.
Speaker 1: That's that's not a suggestion for something somebody should do.
Speaker 1: And actually, two point two microseconds it is kind of
Speaker 1: a long time for a particle that's this massive to last.
Speaker 1: And so what does it mean that it disappears or
Speaker 1: breaks up like it? It's just unstable like it, just
Speaker 1: it's made out of other things and it breaks up
Speaker 1: or literally just kind of evaporates into energy and that
Speaker 1: energy turns into something else. Yeah, that's a great question.
Speaker 1: These are fundamental particles, so they're not made up of
Speaker 1: anything else. As far as we know. The muon turns
Speaker 1: into the electron. It's not like it has an electron
Speaker 1: inside of it, and it breaks up into an electron
Speaker 1: and other stuff it converts. It goes from a muan,
Speaker 1: it turns via the weak force into a W particle
Speaker 1: and a neutrino, and then the W particle turns into
Speaker 1: an electron and another neutrino. So the muon turns into
Speaker 1: an electron and two different neutrinos, but it didn't have
Speaker 1: those bits inside of it. Remember, particle physics is like alchemy.
Speaker 1: We can convert one kind of matter into another kind
Speaker 1: of matter. Okay, so it's um. It doesn't break apart,
Speaker 1: it's just somehow. It's it's very existence. The universe sort
Speaker 1: of doesn't like it. Like it. It can just seesis
Speaker 1: to exist and in favor of other things existing instead
Speaker 1: of it. Yeah, and this is true for every particle
Speaker 1: that is pretty massive. The universe doesn't like massive particles.
Speaker 1: It's like putting a particle on the top of a hill.
Speaker 1: Eventually it's going to roll down. And so the muon
Speaker 1: is like the at the top of the on. The
Speaker 1: electron is rolling down to the bottom of the hill.
Speaker 1: Eventually the muon is going to turn into the electron.
Speaker 1: And every particle in nature that that can do this
Speaker 1: does this. The only reason the electron doesn't is that
Speaker 1: there's no lighter particle for it to turn into. Oh,
Speaker 1: and that's why we are able to exist, because the
Speaker 1: universe does seem to like electrons and quarks which make
Speaker 1: us up. And so that's why we were stable. But
Speaker 1: if we were made out of me as, we would
Speaker 1: disappear pretty quickly. Yes, exactly. We are made up of
Speaker 1: the lightest particles out there, up corks and down corks.
Speaker 1: Of the lightest corks. Electrons are the lightest version of
Speaker 1: that kind of particle called a lepton. So the matter
Speaker 1: that makes us up that's stable is made out of
Speaker 1: stuff that can't turn into lighter stuff because there is
Speaker 1: no lighter stuff for it to turn into. Right, Yeah,
Speaker 1: there's nothing for it to turn into, so we we
Speaker 1: stay where we are. But the muon is heavy and
Speaker 1: could turn into something else. So it does precisely. And
Speaker 1: for those of you wondering, like, well, what about a photon?
Speaker 1: Why can't an electron turn into a photon? Of photon
Speaker 1: is mass lists Remember that there are rules about how
Speaker 1: these things happen, and one of those rules is conservation
Speaker 1: of electric charge. An electron has a minus one charge,
Speaker 1: so it can't turn into a photon which has zero charge,
Speaker 1: because you have to somehow disappear that charge. The only
Speaker 1: way for that to happen is for an electron to
Speaker 1: hit a plus one positron, and then they can turn
Speaker 1: into a photon together, but for a particle to just
Speaker 1: spontaneously decay, it has to convert to another particle that
Speaker 1: has all the same sort of quantum mechanical numbers. Okay,
Speaker 1: so the muon is the electrons massive cousin or massive
Speaker 1: sort of like alternate universe version of the electron. Right, Yeah,
Speaker 1: it's two hundred times the mass of the electron. It's
Speaker 1: really really massive. That's a lot. It's like crunched into
Speaker 1: the same meat. Yes, exactly. It's like if you met
Speaker 1: another version of you, but you weren't bigger, you were
Speaker 1: denser or something. You're two hundred times as much mass,
Speaker 1: but still fundamental. And it doesn't hang around existence very long,
Speaker 1: and it usually breaks up into or not breaks up
Speaker 1: into runs into lighter particles, so we don't really seed
Speaker 1: around that much. But still it's sort of an important
Speaker 1: part of the universe, and it seems that it's important
Speaker 1: part of the universe and also tells us a lot
Speaker 1: about the mysteries of how everything is put together. Yeah,
Speaker 1: and it actually lasts a long time for a heavy particle.
Speaker 1: Other particles that are heavy, like the Higgs boson, they
Speaker 1: decay much more quickly. They decayed in like ten to
Speaker 1: the minus twenty seconds, whereas this one decays very slowly,
Speaker 1: it's just two point two microseconds. And the reason is
Speaker 1: that it decays via the weak force, which is very weak.
Speaker 1: To the weaker the force, the longer takes for that
Speaker 1: decay to happen. M hmm. All right, let's get into
Speaker 1: that a little bit more, and also how it was
Speaker 1: discovered and why it is such an important particle. But
Speaker 1: first let's take a quick break. All right, So the
Speaker 1: meuan decays by the weak force. What does that mean?
Speaker 1: How can something decay via a force like the force
Speaker 1: makes a decay? Yeah, the fource sort of provides the
Speaker 1: avenue for the decay to happen. Like, how does a
Speaker 1: muon turn into an electron just just roll down a
Speaker 1: hill and say, hey, now I'm an electron. It has
Speaker 1: to has to be an interaction there. And so what
Speaker 1: happens is the muon turns into a W particle and
Speaker 1: a neutrino. And the W particle, remember, is the particle
Speaker 1: of the weak force. It's like the weak force version
Speaker 1: of the photon. And so that's what we mean when
Speaker 1: we say uses the weak force to decay. It doesn't
Speaker 1: just spontaneously happen. Something has to sort of carry that information,
Speaker 1: so it has to make it happen. It's like a reaction,
Speaker 1: and that reaction always includes one of the forces, and
Speaker 1: in this case it uses the weak force, right, and
Speaker 1: that weak force came out of just its own energy.
Speaker 1: It uses the mass. Right. The muon is a huge
Speaker 1: amount of energy in it because it has so much mass,
Speaker 1: and that mass is turned into the energy of the
Speaker 1: electron and the neutrinos that come out of it. So yeah,
Speaker 1: the weak force turns the mass of the muan into
Speaker 1: very small masses of these other particles and gives them
Speaker 1: a lot of energy, right, and it ends up as
Speaker 1: an electron and to neutrinos precisely. All right, Well, to
Speaker 1: tell us Daniel, how was it discovered and why is
Speaker 1: this an important particle? Well, it was discovered initially in
Speaker 1: cosmic rays. Um. People saw these particles just sort of
Speaker 1: shooting from the sky and they didn't understand what was
Speaker 1: making them, and they thought, oh, well, you know, we
Speaker 1: found a few particles, so these are probably electrons. This
Speaker 1: is you know, in the early nineteen hundreds, we didn't
Speaker 1: have a really deep understanding of how particles work. We
Speaker 1: didn't have a good bench of particles, and so people thought,
Speaker 1: you know, everything they saw they thought in terms of
Speaker 1: the particles at the time. So you have to sort
Speaker 1: of wind your mind back to what we knew at
Speaker 1: the time. Back then, we knew about protons, we knew
Speaker 1: about neutrons, we knew about electrons, and so people saw
Speaker 1: these particles shooting from the sky. They didn't know what
Speaker 1: made them, but what they saw was that they penetrated
Speaker 1: really far into matter, much more than electrons could. We
Speaker 1: saw the actual nuance and not the not what it
Speaker 1: looks like after it decays or turns into something else.
Speaker 1: Like we actually you can actually see and feel the muants.
Speaker 1: You can't really feel them, but you can make particle
Speaker 1: detectors that can detect them. You can actually do this
Speaker 1: in your garage using something called the cloud chamber. They
Speaker 1: were able to see them using detectors that they put together.
Speaker 1: And these detectors were like a cubic piece of film,
Speaker 1: like remember the old way films worked, where like light
Speaker 1: was exposed on the film. You didn't have a digital
Speaker 1: camera or anything, and that made some kind of chemical change.
Speaker 1: You're saying, you can make like a solid cube of this. Yeah,
Speaker 1: you just take a solid cube of it, you leave
Speaker 1: it up on a mountain and you leave it there
Speaker 1: for like six months, and then you cart it back
Speaker 1: down or you guys your grad students to do that.
Speaker 1: Then you slice it into pieces and then you can
Speaker 1: develop each of those. And what you do is you
Speaker 1: see all the particles that shot through it in those
Speaker 1: six months, and so they can see and when they
Speaker 1: did this, they saw all these particles shooting through this
Speaker 1: film and they were surprised at how far they were going,
Speaker 1: because electrons shouldn't get that far. Electrons penetrating a little
Speaker 1: bit and then they stopped. But these particles were shooting
Speaker 1: all the way through. It's kind of like a bull
Speaker 1: in a china's shop universus, like a mouse in a
Speaker 1: china shop. Yeah, And they didn't understand that. They thought, well,
Speaker 1: you know, are there two kinds of electrons or there's
Speaker 1: sometimes electrons can penetrate really far. It was really a
Speaker 1: puzzle at the time. What made them think it was
Speaker 1: an electron? Why couldn't it be like, uh, some kind
Speaker 1: of new atom or something. We did know it had
Speaker 1: negative charge, and so I think that's what made people
Speaker 1: think it was more likely to be an electron or
Speaker 1: something like an electron than something positive like inside the nucleus.
Speaker 1: And remember, at the time, we only knew basically about protons, neutrons,
Speaker 1: and electrons, and so everything we saw where like all
Speaker 1: of a sudden, having this imagination that we could just
Speaker 1: explain everything in the universe in terms of these particles,
Speaker 1: and that was It was a great success of the
Speaker 1: particle model at the time, right, like everything could be
Speaker 1: built out of protons, neutrons, and electrons. What a wonderful simplification.
Speaker 1: And so when we first saw these particles that penetrated
Speaker 1: really far, we thought, well, it must be one of those, right,
Speaker 1: But it was not. It was not, and people were
Speaker 1: able to then later douce it in the laboratory using
Speaker 1: collisions and and all sorts of other stuff, and they
Speaker 1: discovered that if you put it in a magnetic field,
Speaker 1: it didn't bend as much as an electron. And that's
Speaker 1: when they decided, you know what, this must be a
Speaker 1: different kind of thing. It's like a new version of
Speaker 1: the electron, a different flavor of the electron, because it
Speaker 1: must be more massive, which is why it doesn't bend
Speaker 1: inside the magnetic field as much reflected as much because
Speaker 1: it has so much mass, it that just has more inertia. Precisely,
Speaker 1: it takes a stronger magnetic field to bend a mu
Speaker 1: on than it does for an electron. And this was
Speaker 1: kind of a scandal in particle physics at the time. Scandal. Yeah,
Speaker 1: people were upset. They were like, what a mu on?
Speaker 1: Who ordered that? Like, we don't need this. Get out
Speaker 1: of here with your ridiculous new particle. We have this
Speaker 1: beautiful description of the universe. We don't want more particles.
Speaker 1: Up until then, everything that you knew about helped make
Speaker 1: the universe. It's kind of what you're saying, like everything
Speaker 1: you knew about at a purpose. Yeah, we had taken
Speaker 1: apart the stuff around us and found the basic building blocks,
Speaker 1: and then we didn't. Some people were like I don't
Speaker 1: want to hear stories about other building blocks that could
Speaker 1: be out there. It just sort of confuses the issue, right,
Speaker 1: It's a shift in the question not just what are
Speaker 1: we made out of? But what is the basic organizing
Speaker 1: principle of the universe. It shows you all of a
Speaker 1: sudden that there's a larger question you didn't even think
Speaker 1: to ask. It's like you find something that you don't
Speaker 1: know what to do with it, like it it doesn't
Speaker 1: help you with what you knew about how things work. Yeah,
Speaker 1: you're putting together jigsaw puzzle and all of a sudden,
Speaker 1: somebody hands you like a really big piece that just
Speaker 1: doesn't fit, and you're like, what I didn't ask for,
Speaker 1: that I don't need. That doesn't help me with my problem. Like, well,
Speaker 1: but okay, but this piece is here and it's not
Speaker 1: going away, right, Yeah, And so it makes you think
Speaker 1: that maybe there's another puzzle, or that the puzzle is
Speaker 1: bigger than you think it is. Yes, all of a
Speaker 1: sudden you realize this is a three dimensional puzzle and
Speaker 1: you've been only playing on on two dimensions, and and
Speaker 1: it just blows your mind. And so that's. Ah, it's
Speaker 1: sort of an earthquake, an intellectual earthquake through the field
Speaker 1: at the moment. But also it's a great opportunity. Those
Speaker 1: are the kind of discoveries that make you realize, Wow,
Speaker 1: there's a whole larger question to ask, and there's a
Speaker 1: whole world of answers out there. And of course now
Speaker 1: we know there's not just the meal one. There's also
Speaker 1: the Tao, which is the even heavier version of it,
Speaker 1: and that every particle has these cousins. Yeah. I like
Speaker 1: how this counts as a scandal in physics, Like was
Speaker 1: it on the front page of the Daily Physics News
Speaker 1: or the National Enquiring Enquirer of Physics? Um newspapers, people
Speaker 1: to tabloids. People had to give testimony about this and
Speaker 1: there You know, physicists are not that exciting, so we
Speaker 1: just got to create drama wherever we can. There was
Speaker 1: even more drama because some people had predicted the existence
Speaker 1: of a particle sort of similar to this. Mm hmm,
Speaker 1: what do you mean predicted like just just guessing. Yeah. Well,
Speaker 1: there was a famous physicist named Yukaba the Genius and
Speaker 1: won a Nobel Prize for all sorts of fascinating stuff.
Speaker 1: And he was trying to understand the strong force. He
Speaker 1: was like, okay, the weak force, we have that one.
Speaker 1: We have the photon for the electromagnetism um, but what
Speaker 1: mediates the strong force? And he did some calculations that
Speaker 1: he thought, I bet there's a particle out there about
Speaker 1: two hundred times the mass of the electron and it
Speaker 1: mediates the strong force. All right, So that's his prediction, right,
Speaker 1: And back in the day, physics would just make predictions,
Speaker 1: like here's my idea and here's what I predict, Like
Speaker 1: we need this for this for what we know to
Speaker 1: make sense. Yeah, just like with the Higgs Boson. Peter
Speaker 1: Higgs said, this doesn't make sense to me, but if
Speaker 1: you look at the universe in a new way, then
Speaker 1: it makes more sense. And this new way predicts a
Speaker 1: new particle, so you can test my theory. That was
Speaker 1: what you Kala did, and he predicted a new particle
Speaker 1: about two hundred times the mass of the electron. Then
Speaker 1: they found this particle and you Kal was like, who
Speaker 1: I was right, But it turns out this particle has
Speaker 1: nothing to do with the strong force at all. So
Speaker 1: it's just like a coincidence, right, And he still got
Speaker 1: the Nobel Prize. He still got the Nobel Prize, but
Speaker 1: not for this and um, not for this one. But
Speaker 1: he's sort of the reason why this particle has a
Speaker 1: strange name. Oh really, he he was a fan of Cows.
Speaker 1: I don't know if he liked Kobe Beef, you know,
Speaker 1: the guy's Japanese or anything, but he you know, we
Speaker 1: had the electron, which is really really light, and we
Speaker 1: had the proton, which is like two thousand times the
Speaker 1: mass of the electron, and he predicted a particle sort
Speaker 1: of an intermediate mass, and so he wanted it called
Speaker 1: like the you know, the mazo tron something where mazing
Speaker 1: means like middle, and so that was the sort of
Speaker 1: the origin of this, like, let's call these particles here,
Speaker 1: you know, in this mass region, we'll call the meso particles. Well,
Speaker 1: what do you have to call it the messo on
Speaker 1: or messing on or I feel like just to be
Speaker 1: consistent here. And then later people were like, well, it's
Speaker 1: not really have anything to do with these other particles
Speaker 1: we found in the same mass, but we'll just keep
Speaker 1: calling it the muon anyway, I bet he wanted to
Speaker 1: call it the me on. I'm so smart. Yeah, but
Speaker 1: this is where like, come on, dude, but it's a
Speaker 1: it's a fascinating moment in physics because or the yuan
Speaker 1: is the mean, or how about we calling muan done compromise.
Speaker 1: That's exactly how these decisions get made, and that's why
Speaker 1: we have such terrible names for particles. Yeah. So, but
Speaker 1: now it's so it's a well known thing, like everyone
Speaker 1: knows about muans. Did they know that they're there and
Speaker 1: you can study them. You can. You can. They're coming
Speaker 1: through going through our bodies right now at ten thousand
Speaker 1: times per minute. Yeah, ten thousand muans per square meter
Speaker 1: per minute, and you're right. At first it was totally
Speaker 1: exotic and what is this weird thing? And now we
Speaker 1: know it's a relative of the electron, but also created
Speaker 1: another field, which is cosmic ray physics. It was the
Speaker 1: first cosmic ray scene. And at first people weren't sure,
Speaker 1: like where are these particles coming from? We know they're
Speaker 1: coming down from the sky, but are they made in
Speaker 1: the sky or whatever. And people did all these crazy experiments,
Speaker 1: like balloon experiments with a shot detectors up into the
Speaker 1: atmosphere with balloons and discovered that the higher up you go,
Speaker 1: the more muans there are, and that tells you that
Speaker 1: like muanes are being created in the upper atmosphere, and
Speaker 1: then they're decaying as they sort of come down to Earth.
Speaker 1: And finally people put together this picture like particles were
Speaker 1: hitting the top of the atmosphere and creating these showers
Speaker 1: of particles and we were just sort of picking up
Speaker 1: the little last bits of the fireworks as they hit
Speaker 1: the surface. Right. I bet they also try to shoot
Speaker 1: a cow to the moon. That's where the inspiration. Well,
Speaker 1: you know how the Russians put a dog in one
Speaker 1: of their first attempts to go to space. I won't
Speaker 1: comment as to whether particle physicists ever used a weather
Speaker 1: balloon to launch a cow. Yeah, they're like, we gotta
Speaker 1: up those Russians a dog. Anyone can launch a dog
Speaker 1: into space. This is this is well before the space race.
Speaker 1: This is the cow race. But I love thinking about
Speaker 1: what it must have been to be a physicist at
Speaker 1: that time, and too like crack in a whole new
Speaker 1: era of discovery bye bye, you know, putting photographic plates
Speaker 1: up on mountains and just seeing like what's up there.
Speaker 1: There's so many amazing things to discover. Somebody like new
Speaker 1: World were opened up. They discovered that all this invisible
Speaker 1: stuff is happening around us. That's really wonderful to sort
Speaker 1: of like crack open a new way of looking at
Speaker 1: the universe. Yeah, all right, let's get into the last
Speaker 1: bit here, which is what does the Muan teaches, what
Speaker 1: does it tell us about how the universe is put together?
Speaker 1: But first let's take another quick break, all right, I know,
Speaker 1: so the muan is a thing. It's there. It's super massive,
Speaker 1: looks just like the electron. We can feel it. It's
Speaker 1: going through us right now. Why is it there? That's
Speaker 1: the question that maybe a lot of people have. I mean,
Speaker 1: we don't need the muan to make iPhones or ezas,
Speaker 1: so why is it there? Is that the standard upon
Speaker 1: which we judge things. Now, if we don't need you
Speaker 1: for iPhones or pizzas, you don't need to exist. What
Speaker 1: else is there? Daniel? That's my whole life basically, just personally.
Speaker 1: Um No, it's a good question. It's a question I'd
Speaker 1: like to know the answer to. Why does the muan exist?
Speaker 1: The short version of the answer is the title of
Speaker 1: a great book I read last year. It's called We
Speaker 1: Have No Idea? Because we really do have new idea.
Speaker 1: Why the muan is there? Doesn't seem to be used
Speaker 1: for anything, is what you're saying. Like neutrinos, I think
Speaker 1: also are there, but we don't know why why they're
Speaker 1: they're right, Yeah, neutrinos and muans and many of the
Speaker 1: other particles are not part of the atom. You know,
Speaker 1: build them, You don't use them to build up the
Speaker 1: stuff that we're familiar with, but they sort of can
Speaker 1: exist there on Nature's menu. You might ask the same
Speaker 1: question about like some of the really heavy elements, like
Speaker 1: why is plutonium a thing? Well, it turns out you
Speaker 1: can assemble protons and new trons and electrons in this
Speaker 1: way that's stable, and it hangs out and it does
Speaker 1: this funny thing. We call it plutonium, and plutonium also
Speaker 1: the case, right, it like breaks up. This one actually
Speaker 1: breaks up into other things. But it's also kind of ephemeral,
Speaker 1: like it's only there for so long before it becomes
Speaker 1: something else. Precisely, and in the same way we organize
Speaker 1: our list of particles, and we want to like, why
Speaker 1: are these there? What does this tell us about maybe
Speaker 1: one deeper layer of reality, Like maybe the muans and
Speaker 1: electrons are made out of smaller particles and these are
Speaker 1: just like different ways to assemble those little internal bits, right,
Speaker 1: And there's a few ways to assemble them, the way
Speaker 1: that there's a few ways to assemble protons and neutrons
Speaker 1: to get different elements. Maybe there's a few ways to
Speaker 1: assemble these little tiny ons. One way is to get
Speaker 1: an electron, in other ways to get a muan, in
Speaker 1: other ways to get a towel, which is the third
Speaker 1: member of that family. We just don't know. We know
Speaker 1: it's a clue, though, right, it's a tantalizing clue that
Speaker 1: there's something going on here. We just don't know what
Speaker 1: it means. It's a clue as to some sort of
Speaker 1: hint that there's some sort of rule for how electrons exist.
Speaker 1: Like if you can make an electron that's heavier, maybe
Speaker 1: that tells you something about what makes an electron an
Speaker 1: electron precisely, and why there are three of them tells
Speaker 1: you something about how that rule has to play out.
Speaker 1: Because there's three electrons, the electron, the muant in the towel,
Speaker 1: there's three neutrinos. There's also three up corks is three
Speaker 1: down quarks. Like there's something really fundamental going on there
Speaker 1: we just don't understand. But it seems like an obvious clue.
Speaker 1: You know. It's like you're doing your jigsaw puzzle and
Speaker 1: you find this other weird piece. It turns out, oh,
Speaker 1: that piece fits into a different jigsaw puzzle you didn't
Speaker 1: even know about, and you know it's as you start
Speaker 1: to get this larger picture right or you find it
Speaker 1: like all of your pieces have three sides to them.
Speaker 1: Then you start thinking, you know, whoever made this puzzle,
Speaker 1: if it was made by somebody had a thing for threes, Yeah,
Speaker 1: the universe has a thing for threes, and we don't
Speaker 1: know why that is. The Muan was our first clue
Speaker 1: that particles have copies at all, and now it turns
Speaker 1: out every particle has three copies, and so that's a
Speaker 1: huge open question. Is a kind of question people are
Speaker 1: gonna look back in a hundred years and be like, man,
Speaker 1: that was so obvious. Why couldn't they figure it out?
Speaker 1: If I was a physicist in I would totally figured
Speaker 1: it out. But it's not so easy when you don't
Speaker 1: know the answer when you have to come up with it.
Speaker 1: But it's important for people to understand it's not you know,
Speaker 1: it's not part of the stuff that we are made of,
Speaker 1: but it does answer this larger question. It's like what
Speaker 1: is the sort of context of everything? That's why we're
Speaker 1: trying to figure out, like what are all the particles?
Speaker 1: Because the more particles you put into this table, the
Speaker 1: more clues we get as to what the rules are
Speaker 1: for making this table. And then maybe we can peel
Speaker 1: back a layer and show how this table is put together, right,
Speaker 1: or I guess maybe a question I would have is,
Speaker 1: how do you even know it's a separate thing? Like
Speaker 1: why isn't it just called the heavy electron? Could it
Speaker 1: just be an electron that just gets a lot of
Speaker 1: mass added onto it somehow through energy or something. That's
Speaker 1: a deep question and goes sort of to like what
Speaker 1: do we call a particle? Part of the idea entity
Speaker 1: particle is its mass? Like that's how we identify what
Speaker 1: particle we're talking about. We measure the mass and we say, well,
Speaker 1: if it has this mass, it's an electron a sort
Speaker 1: of semantics, but it's it's what we mean by an electron.
Speaker 1: We mean quantum dot in space that has these properties,
Speaker 1: and one of those is the mass. And there are
Speaker 1: only a few. It's not like this, it's a there's
Speaker 1: a knob you can't have halfway between ELECTRONO mu on
Speaker 1: this like the electron mass, the muan mask, the town mass.
Speaker 1: There's some notches there, right, And so this was the
Speaker 1: first particle that kind of we found outside of the
Speaker 1: ones that make up atoms. Is that what you're saying
Speaker 1: that this was the first one that was weird? Yeah, precisely,
Speaker 1: it's weird and cute. I'm glad you're finally putting positive
Speaker 1: attributes on the on the muon you're trying to make it.
Speaker 1: I said weird, I didn't say cute. I think somebody
Speaker 1: has a particle fetish and it's not the cartoon is. Yes, well,
Speaker 1: maybe the particle physicist has a particle fetish. I will
Speaker 1: totally own up to that. I love you, particles. I
Speaker 1: think we all love particles by necessity. We can't live
Speaker 1: without you, like particles when they make up pizza and iPhones,
Speaker 1: though otherwise you don't care about them. You objectify particles
Speaker 1: and cartoon is cartoonists. Well, I think this particle is
Speaker 1: interesting in that it also kind of hints, you know,
Speaker 1: at the the universe is full, is full of these
Speaker 1: small little details that people can't explain right now, and
Speaker 1: then maybe tell us a little bit about that there
Speaker 1: are other mysteries yet to discover. Yeah, and you know
Speaker 1: the story of how the muan was discovered is also motivational, right,
Speaker 1: people saw this weird stuff in these pictures and they
Speaker 1: could have just shrugged it off. It could have been like,
Speaker 1: I don't know, electrons are doing some weird that day whatever,
Speaker 1: but instead of cracked open this whole other mystery, and
Speaker 1: we are still doing that. We still don't totally understand
Speaker 1: the muan. One thing we'd like to understand is the
Speaker 1: muan's magnetic field. Oh, it's a it's odd. It has
Speaker 1: a weird magnetic field. Yeah. These particles, remember, have quantum spin,
Speaker 1: so they're doing something we like spinning. That's giving them
Speaker 1: each a little magnetic field because they have electric charge
Speaker 1: and spinning charges give magnetic fields. But when we predict
Speaker 1: the magnetic field of the mu want from what we
Speaker 1: know about it, and then we go when we measure
Speaker 1: the magnetic field, it's a little bit different. It's not
Speaker 1: exactly right, And that little difference we could say, I
Speaker 1: don't know, shrug it off. Maybe mu want is doing
Speaker 1: some weird that day, or it could be a clue.
Speaker 1: It could be that the muant is like interacting with new,
Speaker 1: weird heavy particles we haven't even seen before. It could
Speaker 1: be the first evidence that there are more particles out
Speaker 1: there that we haven't yet discovered. And also they help
Speaker 1: us unravel ancient mysteries like maybe you heard about how
Speaker 1: muans are used to take a picture of the inside
Speaker 1: of pyramids. What do you mean, like we can make
Speaker 1: an meon viewer, like like me on glasses. No, you
Speaker 1: can use me on to like x ray a pyramid,
Speaker 1: because what happens is muans, zillion muans shooting from the
Speaker 1: sky through everything. And if you take a muan detector
Speaker 1: and you put it on the other side of something,
Speaker 1: you can tell sort of the density of that thing,
Speaker 1: because muans will penetrate air differently than they'll penetrate raw,
Speaker 1: for example. And so you take a lot of muans,
Speaker 1: you shoot them through something, you can tell whether that
Speaker 1: thing is full, is hollow or not hollow. And so
Speaker 1: they did this recently by looking at muans that went
Speaker 1: through the Great Pyramids, because we're curious, like what's inside
Speaker 1: the Great Pyramid, but you don't want to take it apart,
Speaker 1: and so they use it basically to x ray the
Speaker 1: Great Pyramids, like you put a detector underneath the pyramid
Speaker 1: or or what. Yeah, you take the detectors as far
Speaker 1: underneath the pyramids as you can in some of those
Speaker 1: rooms that do exist. And you know, you can't build
Speaker 1: an x ray gun the size of the pyramids. But
Speaker 1: the sky is a muan gun, right, The sky is
Speaker 1: shooting muans at us all the time. The sky is
Speaker 1: a muan gun. Oh my god. Yeah, put on your
Speaker 1: tin hats, folks, because the sky really is shooting particles.
Speaker 1: That was like, I need like a lead titanium head,
Speaker 1: not a tin head. Maybe, you know, maybe the Pharas
Speaker 1: have the right idea. Maybe that's why they have those
Speaker 1: really weird head dresses. Well, that's what I was going
Speaker 1: to ask, is how do you know what meal On
Speaker 1: look like after they go through aliens? If there are
Speaker 1: aliens inside the pyramid, you wouldn't know. Wow. I was
Speaker 1: so ready with an answer to that question until you
Speaker 1: went to aliens. And now I'm totally at all awesome.
Speaker 1: That's why I'm here, Daniel, to ask the tough questions
Speaker 1: that are on everyone's minds. Joking aside, they did find
Speaker 1: something inside the pyramids. They think they may have found
Speaker 1: a new empty room inside the pyramids that they didn't
Speaker 1: know about before. Is the way the muans full of
Speaker 1: cows before the cows are the aliens actually to wrap
Speaker 1: it all up, then we're in deep trouble when they're
Speaker 1: overlords coming and they're like, what are you guys doing?
Speaker 1: And they say, welcome to our our leader, King muon
Speaker 1: the first first of his name. No, they found that
Speaker 1: inside the Great Pyramid there may be a new hollow
Speaker 1: section that nobody knew about before. And it's only things
Speaker 1: to Muans that we were able to Muan x ray
Speaker 1: the p It's a new on chamber they found. Thanks. Yes,
Speaker 1: so it may not be inside your iPhone and it
Speaker 1: may not be inside your pizza, but it does help
Speaker 1: unravel ancient mysteries about ancient civilizations. Al Right, well, with that,
Speaker 1: we will wrap it up and we hope you enjoyed
Speaker 1: that little discussion about this unknown but supermassive and mysterious
Speaker 1: part of the universe, part of our family of cousins, particles, big, small,
Speaker 1: massive or not. We'd love you all, at least I do.
Speaker 1: Thanks for tuning in. See you next time. Before you
Speaker 1: still have a question after listening to all these explanations,
Speaker 1: please drop us a line. We'd love to hear from you.
Speaker 1: You can find us on Facebook, Twitter, and Instagram at
Speaker 1: Daniel and Jorge that's one word, or email us at
Speaker 1: Feedback at Daniel and Jorge dot com. Thanks for listening,
Speaker 1: and remember Daniel and Jorge explain the universe is a
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Speaker 1: or wherever you listen to your favorite shows. Yeah.