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Why do some particles die? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Or Hey, just starting a new decade? Make you feel
• 0:11
  Speaker 1: young or old? What? It's a new decade. It's gonna
• 0:14
  Speaker 1: be very soon when this podcast comes out, it will well,
• 0:18
  Speaker 1: you know, it makes me feel a little bit of both.
• 0:21
  Speaker 1: I guess I feel you old? You old? Is that
• 0:25
  Speaker 1: a quantum superposition of young and old kids? It's both
• 0:28
  Speaker 1: in neither. Well, here's something that might make you feel
• 0:31
  Speaker 1: kind of young. Oh, this is this invent the Fountain
• 0:35
  Speaker 1: of Youth. Still running a grand application for that project.
• 0:38
  Speaker 1: But I know it's more a sense of perspective. All right, well,
• 0:41
  Speaker 1: what is it? I'll take it. Well, did you know
• 0:43
  Speaker 1: that the particles in your body are more than thirteen
• 0:46
  Speaker 1: billion years old? Compared to that, you're like a baby. Wait,
• 0:51
  Speaker 1: you're telling me that I'm a billion years old and
• 0:53
  Speaker 1: that's supposed to make me feel young. Maybe it just
• 0:55
  Speaker 1: means you need a n APP. Sounds good, calculatory. Hi.
• 1:15
  Speaker 1: I'm Jorge. I'm a cartoonists and the creator of PhD Comics.
• 1:19
  Speaker 1: Hi I'm Daniel. I'm a particle physicist and I've seen
• 1:22
  Speaker 1: many many particles pass away. Welcome to a new decade
• 1:26
  Speaker 1: of our podcast. Daniel and Jorge explain the Universe, a
• 1:30
  Speaker 1: production of I Heart Radio, in which we venture forth
• 1:33
  Speaker 1: into a whole new decade and try to understand the universe,
• 1:36
  Speaker 1: a decade perhaps in which we will reveal new secrets
• 1:39
  Speaker 1: about the universe that nobody in human history has ever understood.
• 1:43
  Speaker 1: That's right. We like to talk about the planets and
• 1:46
  Speaker 1: the stars and the cosmos, but also the little tiny
• 1:50
  Speaker 1: things in the universe, the particles that we're all made
• 1:53
  Speaker 1: out of and that are all around us all the time.
• 1:57
  Speaker 1: I'm glad that you said we like to talk about
• 1:59
  Speaker 1: a particle. Sometimes I think it's just me. Well, I'm
• 2:04
  Speaker 1: using the Royal We, the Physicist podcast Arial We. But yeah, well,
• 2:12
  Speaker 1: I do like to talk about particles because I feel like,
• 2:15
  Speaker 1: in the end, we're all made of particles, and if
• 2:17
  Speaker 1: we want to understand the universe, we got to start
• 2:19
  Speaker 1: at the beginning, the smallest, the littlest nuggets. And if
• 2:23
  Speaker 1: we understand the way the universe works at these smallest scales,
• 2:26
  Speaker 1: then we have a chance to maybe understand the way
• 2:29
  Speaker 1: things work at larger scales. Yeah, you know, I think
• 2:31
  Speaker 1: that as human as we tend to kind of forget
• 2:33
  Speaker 1: that fact. You know, we're made out of tiny, little
• 2:36
  Speaker 1: molecules and atoms and tiny little particles. We I think
• 2:39
  Speaker 1: we love to think of ourselves as as these sort
• 2:42
  Speaker 1: of ethereal thinking beings, but really we're just like a
• 2:45
  Speaker 1: giant lego set of particles, right, Yeah, And ever since
• 2:49
  Speaker 1: I learned about quantum mechanics and the frothing vacuum and
• 2:52
  Speaker 1: how particles are popping in out of existence at all times,
• 2:55
  Speaker 1: it gives a different sense for what you are. You
• 2:58
  Speaker 1: are a collection of particles, but that set of particles
• 3:00
  Speaker 1: is changing, so you're more like a storm, like a cloud.
• 3:04
  Speaker 1: You're like an excitation of the space in which you
• 3:07
  Speaker 1: were living. He gives a different sense for what it
• 3:09
  Speaker 1: means to be you. And that's why I want to
• 3:11
  Speaker 1: understand the universe from the smallest scale, because it tells
• 3:14
  Speaker 1: us what it's like to be us, what it means
• 3:16
  Speaker 1: to be a thing. Well, I am definitely hopefully a thing,
• 3:19
  Speaker 1: and I'm definitely in a state of excitation. And I
• 3:22
  Speaker 1: have to say that I did get a fronting vacuum
• 3:25
  Speaker 1: for Christmas, so I'm glad you. Does that mean that
• 3:28
  Speaker 1: it makes phone for your coffee while it cleans the kitchen? Yeah,
• 3:32
  Speaker 1: it's it's it's a multitasker's dream. I'll have the cappuccino
• 3:36
  Speaker 1: vacuum please. Yeah. So, so today we'll be talking about
• 3:40
  Speaker 1: the things that everyone is made out of. You, me, this,
• 3:44
  Speaker 1: this um microphone that I'm speaking to, those speakers that
• 3:47
  Speaker 1: are broadcasting our voices. Everything is made out of particles.
• 3:52
  Speaker 1: And some people might be surprised, maybe or maybe not,
• 3:55
  Speaker 1: that particles don't last forever. That's right, particles are not
• 4:00
  Speaker 1: forever as far as we know. But there are kind
• 4:02
  Speaker 1: of two different kinds of particles. There's the particles that
• 4:05
  Speaker 1: make up me and you, and as we've talked about
• 4:08
  Speaker 1: in the podcast, those are mostly three different particles up quarks,
• 4:12
  Speaker 1: down quirks, and electrons. But then we talk about all
• 4:15
  Speaker 1: these other particles higgs bosons, top quarks, w bosons, and
• 4:20
  Speaker 1: those particles aren't around. You don't like find a pile
• 4:23
  Speaker 1: of them under rock somewhere, and that's because they don't
• 4:26
  Speaker 1: last very long. They flash into existence and then they
• 4:29
  Speaker 1: die very quickly. Hey, can I choose what kind of
• 4:31
  Speaker 1: quarks I'm made out of? Like? Can I be up
• 4:33
  Speaker 1: corks all the time. I don't know what kind of
• 4:35
  Speaker 1: special powers you have as a cartoonist, but if you're
• 4:38
  Speaker 1: made of protons and neutrons, and there's not a whole
• 4:40
  Speaker 1: lot of flexibility, so some of them disappear and some
• 4:44
  Speaker 1: of them are born all the time. Um, And so
• 4:46
  Speaker 1: to be on the podcast will be sort of tackling
• 4:48
  Speaker 1: that crazy phenomenon of what makes particles come into and
• 4:52
  Speaker 1: out of existence. Why is it that some particles were
• 4:55
  Speaker 1: born in the Big Bang and are still around, whereas
• 4:58
  Speaker 1: other particles only get to lie tend to the minus
• 5:01
  Speaker 1: twenty three seconds in our universe. So to be on
• 5:04
  Speaker 1: the podcast, we'll be talking about why do particles die?
• 5:13
  Speaker 1: It make it sound so sad, you know, Oh, I see?
• 5:17
  Speaker 1: Why do particles move on? We talk about why particles
• 5:21
  Speaker 1: are born and what they've accomplished in their brief, beautiful lives.
• 5:25
  Speaker 1: You know, why do particles go to Grandpa's farm where
• 5:29
  Speaker 1: they're running happily and jumping over streams streams of particles?
• 5:33
  Speaker 1: They go to the particle reserve where they're well taken
• 5:36
  Speaker 1: care of. And here's another example of where we're sort
• 5:39
  Speaker 1: of anthropomorphizing particles. Right, Particles definitely don't have feelings and
• 5:43
  Speaker 1: emotions and families and Thanksgiving dinners, but we talk about
• 5:46
  Speaker 1: them as if they are born and as if they die,
• 5:49
  Speaker 1: and I think it just helps us connect to them,
• 5:50
  Speaker 1: it helps us think about them. So some particles decay
• 5:54
  Speaker 1: and others don't. So some particles die and some of
• 5:56
  Speaker 1: them live forever? Is that true? Can some particles live
• 6:00
  Speaker 1: from the beginning of time till the end of time?
• 6:02
  Speaker 1: We can never say for sure. All we can say
• 6:05
  Speaker 1: is what we've seen and were in. Some particles, like electrons,
• 6:08
  Speaker 1: we have never seen them decay, so we can estimate
• 6:12
  Speaker 1: how long the lifetime of an electron is based on
• 6:15
  Speaker 1: never having seen any of them decay and having looked
• 6:17
  Speaker 1: at a lot of them, And the current estimate is
• 6:20
  Speaker 1: like seventeen ga jillion years. Now it might be is
• 6:24
  Speaker 1: that is that? The is? What that in a paper?
• 6:26
  Speaker 1: Actually I rounded up at six point nine gajillion years.
• 6:30
  Speaker 1: But the point is we make some statistical statement and
• 6:33
  Speaker 1: say it must be longer than this very very big number,
• 6:35
  Speaker 1: much longer than the age of the universe, or we
• 6:37
  Speaker 1: would have seen when decay. But we can never be sure.
• 6:41
  Speaker 1: And it's the same with a proton. They're pretty stable.
• 6:43
  Speaker 1: Like if you put an electron in a jar, it's
• 6:46
  Speaker 1: just gonna sit there. It's never gonna turn into anything.
• 6:49
  Speaker 1: It's never going to I guess collide with something and
• 6:53
  Speaker 1: turn into something else. Is that possible? Oh, it certainly
• 6:55
  Speaker 1: could actually could get absorbed and then disappeared. But an
• 6:58
  Speaker 1: electron in isolation could you to sit there forever, the
• 7:01
  Speaker 1: same way a photon can fly across the universe for
• 7:04
  Speaker 1: billions of years and still be a photon. But other particles,
• 7:08
  Speaker 1: you know, you put a neutron in a jar or
• 7:10
  Speaker 1: a top cork in a jar, and it will spontaneously decay,
• 7:13
  Speaker 1: will turn into other stuff. Some of the particles that
• 7:16
  Speaker 1: I am made out of might be zillions of years old,
• 7:19
  Speaker 1: and some of them could be, you know, three years old. Yeah, Unfortunately,
• 7:24
  Speaker 1: most of them are billions of years old. If you
• 7:28
  Speaker 1: were looking to feel young, that's not the way to
• 7:30
  Speaker 1: do it. I'd like to focus on the young part
• 7:32
  Speaker 1: of me, Daniel, I'm young inside. Yeah. And so in
• 7:36
  Speaker 1: particle physics, the technical term we use is that some
• 7:39
  Speaker 1: particles are stable. We think they just hang out forever,
• 7:41
  Speaker 1: they don't do anything, and other particles are unstable because
• 7:44
  Speaker 1: they decay into other particles. And so this is kind
• 7:48
  Speaker 1: of an interesting word, decay and particle using them for particles,
• 7:52
  Speaker 1: and so we were wondering, as usual, how many people
• 7:54
  Speaker 1: out there associate the two works together and know about
• 7:58
  Speaker 1: this process that all particles go through or don't go through. Yeah.
• 8:02
  Speaker 1: So I walked around campus a UC Irvine and I
• 8:05
  Speaker 1: asked people if they knew that heavier particles can decay
• 8:09
  Speaker 1: into lighter particles and why it happens. So think about
• 8:12
  Speaker 1: it for a second. How much do you know about
• 8:14
  Speaker 1: particle decay? And what would you be able to answer
• 8:17
  Speaker 1: if Daniel appros you on the street one day. Here's
• 8:20
  Speaker 1: what people had to say. Do you know that particles decay? No?
• 8:24
  Speaker 1: I didn't. Yes. Do you know why that happens? No? Yes?
• 8:28
  Speaker 1: Do you know why that happens? I'm gonna say energy emissions? Yes?
• 8:31
  Speaker 1: Do you know why that happens? A great active decay?
• 8:35
  Speaker 1: You know what is it? I just know that if
• 8:37
  Speaker 1: as too many neutrons and it's center, it's like unstable,
• 8:42
  Speaker 1: so they can't I'll stay they shut off. No, I
• 8:47
  Speaker 1: did not know that. I don't know because like there's
• 8:49
  Speaker 1: some kind of potentials high for them. I'm actually not sure.
• 8:52
  Speaker 1: Do you know why that happens? Uh? No, but I
• 8:55
  Speaker 1: do know, like the half life of particles, and so
• 8:59
  Speaker 1: all right, a couple of yes and no answers. None
• 9:02
  Speaker 1: of the answers changed, none of the answers decayed. They're
• 9:06
  Speaker 1: all stable in their ignorance of this question. You know,
• 9:09
  Speaker 1: some people said yes, and are you saying they maybe
• 9:12
  Speaker 1: they said yes, but they didn't really know. Some people
• 9:14
  Speaker 1: said yes, they know that it does happen, but they
• 9:17
  Speaker 1: weren't really clear on why. And when I pressed them,
• 9:19
  Speaker 1: they just sort of described the process that happens, you know,
• 9:23
  Speaker 1: like they have short lifetimes. That's like asking, you know,
• 9:26
  Speaker 1: why does something I have a short lifetime? Because it
• 9:28
  Speaker 1: has a short lifetime. There isn't really there wasn't really
• 9:30
  Speaker 1: much understanding for why it happens, Like why can these
• 9:33
  Speaker 1: heavy particles not just stick around forever? I see? Well,
• 9:36
  Speaker 1: some people said radioactive decay, But that's that's a little
• 9:40
  Speaker 1: bit different, right, that's when a whole atom sort of
• 9:43
  Speaker 1: breaks down, not a particular particle. Yeah, it's a little
• 9:46
  Speaker 1: bit different, but it's actually the same thing because what's
• 9:48
  Speaker 1: going on inside radioactive decay is just a particle decay.
• 9:53
  Speaker 1: It has an impact on the rest of the Atomate
• 9:55
  Speaker 1: changes the automate changes a neutron into a proton and
• 10:00
  Speaker 1: that changes what the atom is. But radioactive decay is
• 10:02
  Speaker 1: actually just an example of one of the particles inside
• 10:05
  Speaker 1: the atom decay. Oh wow, so it's like a Russian doll. Yeah, precisely.
• 10:09
  Speaker 1: Well that's what reality is. It's like Russian dolls, right,
• 10:11
  Speaker 1: you get these layers and layers of reality. Yeah, it
• 10:14
  Speaker 1: all leads back to Russia. We were going to try
• 10:18
  Speaker 1: to avoid politics on the show, but it's the new
• 10:21
  Speaker 1: in the New decade. We're not doing politics, all right,
• 10:23
  Speaker 1: So pretty good answers. And I have to admit I
• 10:25
  Speaker 1: don't know why particle decay. I know that they decay,
• 10:29
  Speaker 1: and they sometimes spontaneously trying to do other things, but
• 10:33
  Speaker 1: I also don't know why some of them don't decay.
• 10:35
  Speaker 1: That's kind of puzzling to me. So let's get into
• 10:38
  Speaker 1: a Daniel. Well, let's maybe define for people first, what
• 10:42
  Speaker 1: is particle decay. Yeah, decay is a funny word because
• 10:45
  Speaker 1: it implies like you've died and your bits are sort
• 10:48
  Speaker 1: of falling apart and blowing away in the winds really dramatically, right,
• 10:52
  Speaker 1: But really, by decay, we just mean that a particle
• 10:55
  Speaker 1: turns into other particles like it's it was kind of
• 11:00
  Speaker 1: particle and then an instant later it's like it's broke apart.
• 11:04
  Speaker 1: Did break apart or does it transform? Yeah, that's exactly it.
• 11:08
  Speaker 1: It doesn't break apart. It transforms like when a higgs
• 11:11
  Speaker 1: boson turns into a pair of bottom corks, which it
• 11:15
  Speaker 1: likes to do. It's not like it was made out
• 11:18
  Speaker 1: of a pair of bottom quarks and it broke up
• 11:20
  Speaker 1: into those. This is not like you're taking a molecule
• 11:24
  Speaker 1: of water and splitting it into the hydrogen and the
• 11:26
  Speaker 1: oxygen that you can do. But when particles decay, they
• 11:30
  Speaker 1: transform from one kind of matter to another. It's really
• 11:33
  Speaker 1: it's alchemy. So the higgs boson was not made of
• 11:36
  Speaker 1: bottom quarks. It transformed from higgs boson into a pair
• 11:40
  Speaker 1: of bottom corks. It's kind of like when the Beatles
• 11:42
  Speaker 1: broke up. It's not that they it's almost up. Good,
• 11:50
  Speaker 1: I'm glad, I'm right, Okay. So it's not like a
• 11:55
  Speaker 1: case like it breaks down, but it's more like, um,
• 11:59
  Speaker 1: it just decide it to be something else totally. Yeah.
• 12:02
  Speaker 1: And it's not like it's making a decision, right, It's
• 12:03
  Speaker 1: like it's alive and his moods and it's like today
• 12:06
  Speaker 1: I'm not feeling it. I just want to be be
• 12:08
  Speaker 1: corks today. How do you know, Daniel, how do you
• 12:10
  Speaker 1: know his bosons? I've interviewed them. They're not very insightful.
• 12:15
  Speaker 1: You talk to them to find out that they don't talk.
• 12:17
  Speaker 1: Is that what you're saying. I try to interview them.
• 12:19
  Speaker 1: You know, their agent never calls me back, so you
• 12:22
  Speaker 1: know they're super important or they have nothing to say.
• 12:25
  Speaker 1: And we see the same process happened for lots of
• 12:27
  Speaker 1: other particles and not to the Higgs boson. Right, Really,
• 12:30
  Speaker 1: the neutron decays into a proton, and when it does so,
• 12:33
  Speaker 1: it kicks out an electron and some neutrino um. The
• 12:36
  Speaker 1: top cork decays into a W and a B corks.
• 12:39
  Speaker 1: This kind of stuff happens all the time. Like, what
• 12:41
  Speaker 1: do you mean It kicks out like it transformed into
• 12:43
  Speaker 1: one thing and another thing, but one of the things
• 12:46
  Speaker 1: flies away. Yeah, a particle can turns. We'll get into
• 12:50
  Speaker 1: this a little bit later. There are a lot of
• 12:51
  Speaker 1: rules for how particles decay, but one of the most
• 12:53
  Speaker 1: important one is that a particle cannot decay into one
• 12:56
  Speaker 1: other single particle. It can only decay into multiple particles.
• 13:00
  Speaker 1: So when a neutron decase, It decays into a proton
• 13:02
  Speaker 1: and an electron and an anti neutrino. And this is
• 13:05
  Speaker 1: what we called beta decay. This is actually what happens
• 13:08
  Speaker 1: inside the nucleus when an atom radioactively decays, is that
• 13:11
  Speaker 1: one of the neutrons is turned into a proton. And
• 13:14
  Speaker 1: this is all kind of that quantum mechanical magic. Don't
• 13:17
  Speaker 1: say magic, not magic, quantum mechanical wizardry. Science. Man's you
• 13:24
  Speaker 1: used to word alchemy? How is that any different? Alchemy
• 13:27
  Speaker 1: is science. For a long time people thought it was nonsense, impossible,
• 13:31
  Speaker 1: but then it turns out it's actually possible. We do
• 13:33
  Speaker 1: it all the time, so it's been brought back into science.
• 13:36
  Speaker 1: Well maybe he'll disabill happen for a wizardry. Okay, alright, alright,
• 13:41
  Speaker 1: I'll compromise. We'll call it quantum witching about that in
• 13:45
  Speaker 1: one way? Is that a compromise? I don't quite understand,
• 13:48
  Speaker 1: But all right, it's quantum something. Yes, yeah, yeah, yeah,
• 13:52
  Speaker 1: I guess what it's. What I mean is that it's
• 13:53
  Speaker 1: not like things are like you said. They don't break
• 13:56
  Speaker 1: apart into into the parts that they're made out of.
• 13:59
  Speaker 1: They literally sort of like become a ball of for
• 14:02
  Speaker 1: more deal energy, and then that energy transforms into other things. Yeah, precisely,
• 14:07
  Speaker 1: you're converting one kind of matter into another kind of matter.
• 14:11
  Speaker 1: And that seems really strange, right, like where did it go?
• 14:14
  Speaker 1: But remember all of these things are particles, and particles
• 14:17
  Speaker 1: are just excited states of the quantum fields. Space is
• 14:20
  Speaker 1: filled with these fields, and sometimes they ripple, and those
• 14:23
  Speaker 1: ripples are particles. So we're really talking about is moving
• 14:27
  Speaker 1: energy from one quantum field, like the Higgs field, into
• 14:30
  Speaker 1: another quantum field, like the field for bottom corks. It's
• 14:33
  Speaker 1: like the excitation passes from one field to the other. Yeah, exactly,
• 14:38
  Speaker 1: just like a wave can move from one kind of
• 14:40
  Speaker 1: fluid into another kind of fluid. Or when you strum
• 14:43
  Speaker 1: a guitar string, you're changing the shaking of the guitar
• 14:45
  Speaker 1: string into the shaking of the air. Interesting, and so
• 14:49
  Speaker 1: we go back to the Beatles because it's it is
• 14:51
  Speaker 1: sort of like the loneliest guitar. All right, Yeah, go
• 14:56
  Speaker 1: you win. You're right, it's just like the Beatles. But
• 15:00
  Speaker 1: that's kind of what we call particle decay or particle death.
• 15:03
  Speaker 1: I guess that. I mean, that's what we mean when
• 15:05
  Speaker 1: when we asked the question why do some particles die
• 15:08
  Speaker 1: because basically the elect the first particle that was there
• 15:12
  Speaker 1: basically stops existing, stops existing, and something else exists. Yeah,
• 15:18
  Speaker 1: and it's and it's bits are no longer there. We
• 15:20
  Speaker 1: don't know if the Higgs boson is made of smaller
• 15:22
  Speaker 1: bits right now we think of it. It's just fundamental.
• 15:24
  Speaker 1: But whatever it is is no longer around. It's not
• 15:27
  Speaker 1: just getting taken apart and rearranged like Jigsaw puscles into
• 15:31
  Speaker 1: something else, like Lego pieces into something else. It's really
• 15:33
  Speaker 1: getting transformed. And that's what we mean. You mean the
• 15:36
  Speaker 1: Higgs is not made out of little Higgy's um. I
• 15:41
  Speaker 1: think the Lego company has a copyrun on that name,
• 15:43
  Speaker 1: so we should avoid using it, all right, So that
• 15:44
  Speaker 1: and so it really dies, right, it's like it's no
• 15:47
  Speaker 1: longer in the universe. Yeah, it's gone. And so we
• 15:51
  Speaker 1: make particles like this in collisions all the time. We
• 15:53
  Speaker 1: collide protons together, we make some heavy particle z W
• 15:57
  Speaker 1: a top cork, Higgs boson, something else, and they live
• 16:01
  Speaker 1: for like ten to the minus twenty three seconds before
• 16:04
  Speaker 1: they turn into something else. And you know, that's what
• 16:06
  Speaker 1: makes it so hard to study these particles that they're
• 16:08
  Speaker 1: not around for very long, so it's hard to talk
• 16:11
  Speaker 1: to them. Wow. Well, it seems like some particles are
• 16:14
  Speaker 1: alive quote unquote for ten to the minus twenty three seconds,
• 16:18
  Speaker 1: and some of them are live for seven bizillion years.
• 16:22
  Speaker 1: It seems unfair, doesn't it. All right, so let's get
• 16:24
  Speaker 1: into why that is and what causes a particle to
• 16:28
  Speaker 1: decay or not. But first let's take a quick break,
• 16:44
  Speaker 1: all right, Daniel, So why does it happen? Why the
• 16:46
  Speaker 1: particles have to die? The key thing to understand is
• 16:49
  Speaker 1: that there's a difference in the mass of these particles.
• 16:52
  Speaker 1: So higher mass particles like the Higgs, like the top
• 16:56
  Speaker 1: they decay into lower mass particles. And this makes simple
• 17:00
  Speaker 1: sense because of conservation of energy. If you have a
• 17:03
  Speaker 1: high mass particle just at rest all of its energies
• 17:06
  Speaker 1: in its mass. If it turns into other particles, those
• 17:09
  Speaker 1: particles have to have lower mass, otherwise you'd be violating
• 17:12
  Speaker 1: conservation of energy. Oh, I see, And it's a it's
• 17:15
  Speaker 1: a spontaneous event, right, Like nothing triggers it. It's not
• 17:19
  Speaker 1: like it bumped into something and it broke up, or
• 17:23
  Speaker 1: you shot you shot a particle at it and then
• 17:25
  Speaker 1: that caused the transformation. It's like it was just sitting
• 17:27
  Speaker 1: there and because it had too much, too much mass,
• 17:31
  Speaker 1: it just suddenly breaks up. Yeah, it's spontaneous. It doesn't
• 17:35
  Speaker 1: need to be triggered from anything from the outside. And
• 17:37
  Speaker 1: it's also random. So if you have like a hundred
• 17:39
  Speaker 1: Higgs bosons and you have them all in an array
• 17:42
  Speaker 1: somewhere and you watch them, some of them would decay
• 17:45
  Speaker 1: very quickly and some of them would live a little
• 17:46
  Speaker 1: bit longer, and it's a distribution there. So we can
• 17:49
  Speaker 1: predict the probability of the Higgs boson decaying after a
• 17:52
  Speaker 1: certain time. You can't predict it for an individual one
• 17:55
  Speaker 1: because it's quantum mechanical. But we know, like what the
• 17:58
  Speaker 1: average lifespan is a Eiggs boson, where the average lifespan
• 18:01
  Speaker 1: is of a top cork, and it's totally random, Like
• 18:04
  Speaker 1: what what I guess? What triggers a death the death
• 18:07
  Speaker 1: of a particle. That's the deepest question in quantum mechanics, right.
• 18:11
  Speaker 1: We know that physics predicts the probability of things happening
• 18:14
  Speaker 1: at various times, but we don't know how the universe
• 18:17
  Speaker 1: makes a decision about what's going to happen when you
• 18:19
  Speaker 1: know in which Shortinger's boxes the cat alive or dead.
• 18:22
  Speaker 1: This is exactly that question, because the way the Shortinger's
• 18:25
  Speaker 1: box works, if you have an atom inside the box
• 18:27
  Speaker 1: that can decay or not decay, and it has a
• 18:30
  Speaker 1: certain lifespan, and if it's already decayed, that's killed the cat.
• 18:33
  Speaker 1: And if it hasn't decated, hasn't killed the cat. And
• 18:35
  Speaker 1: what makes a decision for an individual box We don't know.
• 18:38
  Speaker 1: The universe has some mysteriously not magical um which he
• 18:43
  Speaker 1: dies somewhere that makes those decisions. I see, it's not magic,
• 18:49
  Speaker 1: it's just mysterious. It is mysterious. Now. It's one of
• 18:51
  Speaker 1: my deepest questions about the universe is how it picks
• 18:54
  Speaker 1: random numbers. Where is the universe's random numbers generator? How's
• 18:58
  Speaker 1: that work? Um and and way. That's a deep fascinating question.
• 19:01
  Speaker 1: But the key thing to understand is that higher mass
• 19:03
  Speaker 1: particles decay into lower mass particles. Right that that you're saying,
• 19:07
  Speaker 1: that's like the Golden rule of particle decay. Yeah, there
• 19:11
  Speaker 1: is actually something called the Golden rule, and it helps
• 19:13
  Speaker 1: you sort of do that do onto other particles. As
• 19:17
  Speaker 1: other particles we do onto you. Yeah, I don't know
• 19:20
  Speaker 1: how particles behave and if they're nice to each other
• 19:22
  Speaker 1: or not, but firm me. The golden rule helps you
• 19:24
  Speaker 1: understand sort of why lower mass particles are more likely
• 19:28
  Speaker 1: to exist in the universe than higher mass Like, why
• 19:31
  Speaker 1: don't higher energy, lower mass particles turn into high mass
• 19:34
  Speaker 1: particles all the time. Why does it mostly go the
• 19:36
  Speaker 1: other way? Why do things sort of move down the
• 19:39
  Speaker 1: mass ladder? Well, to to make something heavier rooting, you
• 19:41
  Speaker 1: need to collide with something else and then from that
• 19:44
  Speaker 1: you can like join together. Yeah, and that's exactly what
• 19:47
  Speaker 1: we do in particle collisions. We make these heavy particles
• 19:50
  Speaker 1: very briefly by smashing lower mass particles with a lot
• 19:54
  Speaker 1: of energy together, So we have enough energy to create
• 19:56
  Speaker 1: these high mass particles. But then you might wonder, like,
• 19:59
  Speaker 1: why don't they just stick around? Why don't high mass
• 20:01
  Speaker 1: particles just sit there being high mass particles forever? Right?
• 20:06
  Speaker 1: And is that also a rule? I mean, so, the
• 20:08
  Speaker 1: one rule is that you can only decay do things
• 20:11
  Speaker 1: that are less massive than you, so kind of basically smaller,
• 20:16
  Speaker 1: lighter things. That's one rule. The other rule seems to
• 20:20
  Speaker 1: be that maybe the like the more mass you have,
• 20:23
  Speaker 1: the more the quicker you are you're going to decay.
• 20:25
  Speaker 1: Is there a correlation also in like if you have
• 20:29
  Speaker 1: more mass, the less life you have. Yes, that's certainly true.
• 20:33
  Speaker 1: The more mass you have, the more likely you are
• 20:36
  Speaker 1: to decay quickly. Also, the more ways you have to decay,
• 20:40
  Speaker 1: the more ways you're allowed to decay, the more rapidly
• 20:43
  Speaker 1: you're going to decay. So if you have a really
• 20:44
  Speaker 1: heavy particle but it can only decay via like the
• 20:48
  Speaker 1: weak force, then it's gonna be around for longer because
• 20:50
  Speaker 1: the weak force doesn't act for often. It's very weak.
• 20:54
  Speaker 1: Where if you can decay via the strong force hydronically,
• 20:57
  Speaker 1: then you can decay very very quickly because the strong
• 21:00
  Speaker 1: force is very powerful. Oh so it's kind of like
• 21:03
  Speaker 1: if it has a lot of options, then it's going
• 21:05
  Speaker 1: to take one of those options sooner or later precisely.
• 21:08
  Speaker 1: And the way I like to think about it is
• 21:09
  Speaker 1: that these particles sort of like to relax. They start
• 21:12
  Speaker 1: out in these very high mass states, and you think
• 21:13
  Speaker 1: of it like having a lot of tension, and it
• 21:16
  Speaker 1: wants to relax down to the lower mass the way
• 21:18
  Speaker 1: it's sort of water likes to flow downhill, right, and
• 21:20
  Speaker 1: everything in the universe likes to spread out and cool
• 21:23
  Speaker 1: down and and sort of smooth out, and being in
• 21:27
  Speaker 1: lower mass states is more smooth, has less energy sort
• 21:30
  Speaker 1: of concentrated in one place. So maybe we should rename
• 21:33
  Speaker 1: this episode why the particles like to relax? Why are
• 21:37
  Speaker 1: particles so smooth? All right? So what you're saying, um,
• 21:42
  Speaker 1: this death of this decay, this transformation is really just
• 21:46
  Speaker 1: like the universe kind of reverting or going towards the
• 21:50
  Speaker 1: lowest possible energy state. Yeah, imagine what happens, for example,
• 21:55
  Speaker 1: when you strum a guitar string, right, let's go back
• 21:57
  Speaker 1: to that. You have a lot of energy stored in
• 21:59
  Speaker 1: the guitar string. But then that guitar string interacts with
• 22:02
  Speaker 1: other stuff, right, It can bump into air molecules and
• 22:05
  Speaker 1: give it some of its energy, and then the sound
• 22:07
  Speaker 1: spreads out through the air and you enjoy the music
• 22:09
  Speaker 1: of the Beatles. This is just energy dissipating, right. Why
• 22:13
  Speaker 1: it is energy dissipated. It dissipates because of entropy, because
• 22:16
  Speaker 1: things like to spread out, things like they get more smooth,
• 22:19
  Speaker 1: and so in the same way, you can think of
• 22:21
  Speaker 1: a particle sort of like as the strumming of a
• 22:23
  Speaker 1: quantum field, it's like a field that's oscillating, and if
• 22:26
  Speaker 1: that field can talk to other fields, like the Higgs
• 22:29
  Speaker 1: field can talk to the bottom core field, that it
• 22:31
  Speaker 1: has a way to sort of spread out into those
• 22:34
  Speaker 1: other fields. It's like it's louder and so it it
• 22:38
  Speaker 1: can reach other fields better. Yeah, Or it's like, you know,
• 22:42
  Speaker 1: it's in a box and there are more holes in
• 22:44
  Speaker 1: the box, so it can spread out. If there are
• 22:46
  Speaker 1: lots of really big holes in the box, that it
• 22:47
  Speaker 1: can get out, whereas if you put it in a
• 22:49
  Speaker 1: box and there's almost no holes and it's gonna take
• 22:51
  Speaker 1: a long time for that energy to leak out. And
• 22:53
  Speaker 1: so the lower the mass, then the more stable you are. Precisely,
• 22:58
  Speaker 1: and if there's no particle with or mass than you,
• 23:01
  Speaker 1: than your stable because you can't spread out anymore. So
• 23:04
  Speaker 1: the particles at the bottom of the rungs that have
• 23:07
  Speaker 1: no particles below them, then they can't decay to anything
• 23:10
  Speaker 1: else and so they are stuck. And that's the situation
• 23:12
  Speaker 1: with the electron, because there's nothing with a less mass
• 23:16
  Speaker 1: then you or or do you have to do also
• 23:19
  Speaker 1: with the rules of particles, like an electron can just
• 23:23
  Speaker 1: turn into a super light I don't know, quark or
• 23:26
  Speaker 1: higgs or something. Yeah, there has to be something with
• 23:29
  Speaker 1: less mass than you that you are also allowed to
• 23:31
  Speaker 1: decay into. So, for example, a muan can decay into
• 23:35
  Speaker 1: an electron, it also has to create two neutrinos at
• 23:38
  Speaker 1: the same time for other rules, but the opposite can't happen.
• 23:42
  Speaker 1: Electrons don't decay into muans because muons are heavier than
• 23:45
  Speaker 1: electrons and the electrons are the are the lightest ones,
• 23:48
  Speaker 1: right Tows and muans can both decay into electrons electrons
• 23:51
  Speaker 1: the bottom of the ladder, but electrons can't decay into
• 23:55
  Speaker 1: corks and whatever. And there's all sorts of rules preventing
• 23:57
  Speaker 1: some kind of decays from happening. So um, as long
• 24:01
  Speaker 1: as you're not breaking one of the rules, you always
• 24:02
  Speaker 1: decay into the lightest particle around. Oh I see. So,
• 24:06
  Speaker 1: like a muon can't decay into something that's not an electron,
• 24:10
  Speaker 1: muans almost always decay into electrons. Sometimes a particle will
• 24:14
  Speaker 1: have several things that can decay into. So for example,
• 24:16
  Speaker 1: the higgs can decay into a pair of bottoms, but
• 24:18
  Speaker 1: it can also decay into a pair of photons or
• 24:21
  Speaker 1: a pair of w bosons or something else, or a
• 24:24
  Speaker 1: pair of charm corks or even a pair of electrons.
• 24:27
  Speaker 1: So sometimes a particle will have lots of different places
• 24:29
  Speaker 1: it can go, all right, So there are sort of
• 24:31
  Speaker 1: rules to these decays, but generally they follow that rule,
• 24:35
  Speaker 1: like if you decay, you're going to decay into lower
• 24:38
  Speaker 1: mass particles until you hit the bottom, until you're like
• 24:41
  Speaker 1: the gopher, and then working in the mail room. You
• 24:44
  Speaker 1: can't get fired demoted more than that. Yeah, it's just
• 24:48
  Speaker 1: like that. It's like getting fired down the hierarchy. And
• 24:51
  Speaker 1: once you're at the bottom, you know, um, then you
• 24:54
  Speaker 1: can hang on forever. I guess it's not like having
• 24:57
  Speaker 1: a job, because you could get kicked down this street.
• 24:59
  Speaker 1: But I guess maybe stable particles are the unemployed ones
• 25:02
  Speaker 1: in this analogy. Right, Oh, there you go. You don't
• 25:05
  Speaker 1: have a job, so you can't get fired, all right.
• 25:07
  Speaker 1: And so then that's why some particles never never decay
• 25:10
  Speaker 1: like electrons. You're saying, they can't decay in to anything lighter,
• 25:14
  Speaker 1: and so they just hang around forever. As far as
• 25:18
  Speaker 1: we know, they hang around forever. I mean, we don't
• 25:20
  Speaker 1: know that we know all the list of particles that
• 25:22
  Speaker 1: are out there but for the electron to decay into
• 25:25
  Speaker 1: a lighter particle, there would have to be another particle
• 25:27
  Speaker 1: out there that we hadn't heard it before, and it
• 25:30
  Speaker 1: would have to interact with the electron. So it has
• 25:32
  Speaker 1: to be some force that couples the electron to this
• 25:35
  Speaker 1: particle to allow to decay, to create sort of that
• 25:37
  Speaker 1: hole in the box, to let the electron turn into
• 25:40
  Speaker 1: that other particle. Um. And you know, there are other
• 25:42
  Speaker 1: particles like neutrinos, but electrons can't decay into neutrinos because
• 25:47
  Speaker 1: that violates one of the rules, like electrons have a charge,
• 25:50
  Speaker 1: neutrinos don't. So you can't turn electron into a neutrino
• 25:53
  Speaker 1: because then where does the charge go. There has to
• 25:56
  Speaker 1: be conservation not just of mass, but also all these
• 25:58
  Speaker 1: other quantum magical quantities. Yeah, and we have this whole
• 26:03
  Speaker 1: list and we'll go into it in a minute for
• 26:05
  Speaker 1: all the rules of particles have to follow in the decay.
• 26:08
  Speaker 1: And the things to understand about that is that this
• 26:10
  Speaker 1: is just a list of rules we invented um to
• 26:13
  Speaker 1: sort of describe the things that don't happen. We're like, well,
• 26:15
  Speaker 1: this doesn't happen. Why not, Well, let's make a rule
• 26:18
  Speaker 1: that says it can happen. That doesn't mean we know
• 26:20
  Speaker 1: why the rule is there, right, It's just we've noticed
• 26:23
  Speaker 1: this never happens, and so there must be a reason.
• 26:26
  Speaker 1: We just don't know yet. It's not it's not so
• 26:28
  Speaker 1: it's not it's less rules, but more like trends or
• 26:33
  Speaker 1: you know, things we've never seen happen. Yeah, and our
• 26:36
  Speaker 1: goal is to make the sort of minimal set of trends,
• 26:40
  Speaker 1: like what's the minimal set of rules you need to
• 26:42
  Speaker 1: describe everything we've seen. And then we look at those
• 26:44
  Speaker 1: and we say, well, do this makes sense? And what
• 26:46
  Speaker 1: does it mean about the universe? And can we find
• 26:49
  Speaker 1: a reason why these rules have to exist and stuff
• 26:52
  Speaker 1: like that, And so what are some of the other
• 26:54
  Speaker 1: particles that also live forever? The quarks lift forever. The
• 26:58
  Speaker 1: up corks and the down corps do live forever. Yes,
• 27:01
  Speaker 1: there are no lighter quarks, right. The charm cork and
• 27:04
  Speaker 1: the strange cork, those are heavier, and so they decay
• 27:07
  Speaker 1: into the up and the down and the top cork.
• 27:09
  Speaker 1: In the bottom cork they're even heavier, so they decay
• 27:12
  Speaker 1: also down the ladder to charm and strange and then
• 27:15
  Speaker 1: into up and down. So literally every particle in my
• 27:18
  Speaker 1: body then is is as old as time itself. All
• 27:22
  Speaker 1: the particles in your body are just three different kinds
• 27:24
  Speaker 1: of particles up quarks, down quirks, and electrons. And I
• 27:28
  Speaker 1: think that those particles have been around since just after
• 27:30
  Speaker 1: the Big Bang. None of my particles have were created
• 27:33
  Speaker 1: more recently than that. It's not because you can create
• 27:36
  Speaker 1: those particles. You know, if for example, one of the
• 27:39
  Speaker 1: electrons in your body hits a piece of antimatter coming
• 27:43
  Speaker 1: from a cosmic ray, it can get annihilated into a photon,
• 27:46
  Speaker 1: and then that photon lives very briefly and turns back
• 27:49
  Speaker 1: into an electron and positron, so then it's been reborn.
• 27:52
  Speaker 1: Right in that sense, These particles are always having interaction
• 27:55
  Speaker 1: and and sometimes they get they disappear and come back.
• 27:58
  Speaker 1: So some of these electrons have been born more recently,
• 28:01
  Speaker 1: but it's possible for an electron to stick around the
• 28:03
  Speaker 1: whole lifetime in the universe. Yeah, every particle that I
• 28:06
  Speaker 1: am made out of was made at the Big Bang,
• 28:09
  Speaker 1: or you know, it was there when it all happened.
• 28:12
  Speaker 1: It's got stories to tell around. Yeah. Oh, if you
• 28:15
  Speaker 1: could interview particles, if only they could talk. Part If
• 28:21
  Speaker 1: these particles could talk, these particles could talk, they probably
• 28:24
  Speaker 1: tell stories like in old folks homes, you know, while
• 28:26
  Speaker 1: when I was a kid and I have an onion
• 28:28
  Speaker 1: on my belt and the universe was young. You think
• 28:32
  Speaker 1: you have it bad now? We had to live through
• 28:35
  Speaker 1: the hot plasma. Yeah, I think. I think about what
• 28:38
  Speaker 1: it was like in the Big Bang. We have to
• 28:41
  Speaker 1: walk up hill both ways, all right, So that is
• 28:45
  Speaker 1: kind of what happens is when particles die. And so
• 28:48
  Speaker 1: let's get into a little bit more of what these
• 28:50
  Speaker 1: rules are in more detail and what they mean for
• 28:54
  Speaker 1: us as billion of year old beings. But first let's
• 28:59
  Speaker 1: take a quick break. Yeah, all right, Daniel. So particles die, unfortunately,
• 29:14
  Speaker 1: is just the way of the universe. Uh. And then,
• 29:18
  Speaker 1: and that means that particles sometimes, if they're too heavy,
• 29:20
  Speaker 1: they will transform into lower energy particles until you get
• 29:25
  Speaker 1: to a certain types of particles which apparently never decay,
• 29:30
  Speaker 1: like quorcs and electrons. Yeah, and not just lower energy particles,
• 29:34
  Speaker 1: lower mass particles or lighter particles. As we have this
• 29:37
  Speaker 1: rung of particles and they decay down, down down the rung,
• 29:41
  Speaker 1: and they get to the bottom of the ladder, and
• 29:43
  Speaker 1: they can't decay any further. And the particles ever spontaneously
• 29:46
  Speaker 1: go up the ladder. Absolutely they do. If they get
• 29:49
  Speaker 1: a burst of energy, they absorb some energy, then they
• 29:52
  Speaker 1: can go up the ladder. And that's exactly the kind
• 29:54
  Speaker 1: of thing we do in particle collisions, is that we
• 29:56
  Speaker 1: bring particles together with a lot of energy and low mass,
• 29:59
  Speaker 1: and we create we push them up the ladder briefly,
• 30:02
  Speaker 1: because our question is like what particles are on the ladder,
• 30:05
  Speaker 1: how far up the ladder can you go. It's like
• 30:08
  Speaker 1: we're swimming in very cold, cold universe and we're trying
• 30:11
  Speaker 1: to climb up the ladder to see like what could exist,
• 30:14
  Speaker 1: what used to exist. So we create these pockets, momentary
• 30:17
  Speaker 1: pockets of density to push a particle up the ladder
• 30:20
  Speaker 1: to see like, oh look you can make top quarks.
• 30:22
  Speaker 1: Oh look you can make Higgs bosons. Yeah, And so
• 30:25
  Speaker 1: that kind of answers the question why the particles die
• 30:28
  Speaker 1: is that that's just kind of the way of the universe.
• 30:30
  Speaker 1: Nothing heavy last forever. That's the kind of caveat right,
• 30:34
  Speaker 1: like something's last forever. But if you're too heavy, you're
• 30:37
  Speaker 1: not gonna last for a long time. I feel like
• 30:39
  Speaker 1: that should be on your tombstone. Nothing heavy lads forever,
• 30:44
  Speaker 1: or maybe the you know, the motto of the universe
• 30:47
  Speaker 1: would be like only electrons and quarks last wherever. Yeah,
• 30:50
  Speaker 1: it's true that nothing heavy last forever. It's a deep
• 30:52
  Speaker 1: principle of the universe that things spread out. You know,
• 30:55
  Speaker 1: it's connected to entropy that things tend to like to
• 30:58
  Speaker 1: transform into more relaxed states and the ones with more disorder,
• 31:03
  Speaker 1: and the things that lower mass particles, they just have
• 31:06
  Speaker 1: a lot of different ways to be. Like a higher
• 31:09
  Speaker 1: mass particle, it can basically just sit there. It's used
• 31:11
  Speaker 1: up all of its energy to create this particle. But
• 31:15
  Speaker 1: if it decayed into lower mass particles, then there's a
• 31:18
  Speaker 1: zillion different arrangements for it, and the universe prefers that.
• 31:20
  Speaker 1: It prefers configurations with lots of different arrangements. It's more disorder,
• 31:25
  Speaker 1: and so that's just the way the universe flows. Even
• 31:28
  Speaker 1: for an electron. I guess I'm curious. Even for an electron,
• 31:30
  Speaker 1: you're saying, we'll probably never decay, but but it can,
• 31:34
  Speaker 1: Like can is one of its possibilities that it just
• 31:37
  Speaker 1: one day disappears for no no reason and transform into
• 31:41
  Speaker 1: I don't know, fluton or something. Yeah, potentially, I mean,
• 31:43
  Speaker 1: electrons are stable. But again, all these statements that we
• 31:46
  Speaker 1: make are statistical. We've never seen an electron decay and so,
• 31:51
  Speaker 1: and there are a bunch of rules that prevented from
• 31:53
  Speaker 1: turning into the particles that are lighter than it, things
• 31:56
  Speaker 1: like charge conservation and electron number concert ration, all sorts
• 32:00
  Speaker 1: of other rules we invented just to sort of describe
• 32:03
  Speaker 1: the fact that we never see them decay. But in principle,
• 32:07
  Speaker 1: there could be some lighter particle of the electron that's
• 32:10
  Speaker 1: connected to the electron with some very very weak force
• 32:13
  Speaker 1: that we haven't discovered yet, and eventually, after sixty two
• 32:16
  Speaker 1: chillion years, electrons will decay into those other particles. It's possible.
• 32:20
  Speaker 1: Was that time you used their chillion chilion just invented it.
• 32:25
  Speaker 1: But it's technically like the Chilian it's it represents the
• 32:30
  Speaker 1: flow of the universe. Man, Oh dude, yeah, alright, So
• 32:34
  Speaker 1: I let's getting through these rules because I feel like
• 32:37
  Speaker 1: that's where the meat of this is, right, Like, it's
• 32:39
  Speaker 1: not like any particle can just die spontaneously. It has
• 32:44
  Speaker 1: to follow some rules that the universe seems to follow
• 32:49
  Speaker 1: or maybe not rules. Are these more like we've never
• 32:52
  Speaker 1: seen these things happen, but maybe they but they they're
• 32:55
  Speaker 1: not absolute rules. Maybe. Well, it's that way with all
• 32:58
  Speaker 1: the physics. We see stuff happen. We write down rules
• 33:01
  Speaker 1: that we think describes what happens, and that we hope
• 33:04
  Speaker 1: those rules are fundamental to the universe. But we could
• 33:06
  Speaker 1: be wrong. There could be exceptions to these rules we
• 33:09
  Speaker 1: just haven't observed yet. So in the same way, we're like,
• 33:12
  Speaker 1: you know, let's write down all the results of particle
• 33:14
  Speaker 1: physics experiments, and then let's try to simplify that into
• 33:17
  Speaker 1: a set of rules that we think describes all those experiments,
• 33:20
  Speaker 1: and then we try to understand those rules, like do
• 33:22
  Speaker 1: they make any sense? And why this rule and why
• 33:24
  Speaker 1: of that other rule? Er what are the patterns among
• 33:26
  Speaker 1: the rules. That's sort of the stage we're ad in
• 33:28
  Speaker 1: particle physics. So it's it's interesting to think about what
• 33:31
  Speaker 1: these rules are and what they might mean. I see.
• 33:33
  Speaker 1: So it's kind of like you if you dropped an
• 33:35
  Speaker 1: egg and it broke on the floor, and you dropped
• 33:37
  Speaker 1: an egg again, and it broke on the floor, and
• 33:39
  Speaker 1: you dropped another egg and it's broken the floor, and
• 33:41
  Speaker 1: so and your mom is like, why did I have
• 33:43
  Speaker 1: an experimentalist as a kid? And so you made a
• 33:47
  Speaker 1: rule that set if you drop an egg it'll break. Yeah,
• 33:51
  Speaker 1: and that describes what you've seen and and then of
• 33:53
  Speaker 1: course you should test your prediction and try dropping eggs
• 33:56
  Speaker 1: in other people's houses and tom toomps the mountains and
• 33:59
  Speaker 1: to see if it is a deep rule of the
• 34:01
  Speaker 1: universe or just something specific like if you drop an
• 34:04
  Speaker 1: egg on the space station doesn't break. So it turns
• 34:07
  Speaker 1: out your rule needs to qualifier, right, I see this
• 34:11
  Speaker 1: is a special egg breaking rule only in whore his kitchen,
• 34:16
  Speaker 1: or only on Earth, or only near objects with gravity.
• 34:19
  Speaker 1: If you drop egg, does this break? Yeah, there's a
• 34:22
  Speaker 1: difference between general eggcticity and special eggticity. All right, So
• 34:27
  Speaker 1: what are some of the rules that govern particle decay
• 34:30
  Speaker 1: and just I guess real quickly here. Yeah. Well, one
• 34:32
  Speaker 1: of them we talked about already is that they have
• 34:34
  Speaker 1: to decay from heavier particles in the lighter particles because
• 34:36
  Speaker 1: of conservation of energy. The other is that electric charge
• 34:41
  Speaker 1: has to be conserved, so electrons, for example, can't decay
• 34:45
  Speaker 1: into neutrinos um muans have to decay into electrons. They
• 34:49
  Speaker 1: can't decay into positrons. You have to conserve because the
• 34:54
  Speaker 1: universe can't do anything with that extra charge. Is that
• 34:57
  Speaker 1: it it's like it has to do thing with it. Yeah, precisely,
• 35:01
  Speaker 1: electric charge is conserved. The universe cannot create or just
• 35:04
  Speaker 1: destroy electric charge. It sticks around, and that's not something
• 35:08
  Speaker 1: we understand why. But we've noticed that that it's the
• 35:11
  Speaker 1: case that electric charge is always conserved. I guess my
• 35:14
  Speaker 1: question is where did all this charge come from? Ymtanu
• 35:16
  Speaker 1: the Big Bang? And you know electric charge comes in
• 35:19
  Speaker 1: positive and negative, right, So you can create a positive
• 35:22
  Speaker 1: charge if you also create a minus or photon can
• 35:25
  Speaker 1: turn into an electron and a positron, because the total
• 35:28
  Speaker 1: electric charge is then conserved, all right, So that's a
• 35:30
  Speaker 1: that's another rule you have to concern And that also
• 35:34
  Speaker 1: works for the other charges I imagine, right, like the
• 35:37
  Speaker 1: color charge and the the smelly charge and all the
• 35:42
  Speaker 1: other charges. Yeah, for the other charges, there are similar
• 35:45
  Speaker 1: conservation rules. And you know these charges also are important,
• 35:49
  Speaker 1: for example, because the photon can only interact with charge particles.
• 35:53
  Speaker 1: So for example, the photon can turn into a electron impositron,
• 35:57
  Speaker 1: but it can't decay into neutrinos and interact with neutrinos
• 36:01
  Speaker 1: at all because it only talks to the electron and
• 36:04
  Speaker 1: the positron. Can it kind of do like a three
• 36:07
  Speaker 1: point turn like kind of decay into an electron which
• 36:10
  Speaker 1: then decase into a neutrino. Well, remember electrons are stable,
• 36:13
  Speaker 1: so if a photon decase and electrons, it can't then
• 36:15
  Speaker 1: turn into neutrinos. But if a photon decayed into like
• 36:19
  Speaker 1: a muon and an anti muon, that muant an antimu
• 36:22
  Speaker 1: and could then turn into a pair of electrons and
• 36:24
  Speaker 1: positrons and produce neutrinos at the same time. So yeah,
• 36:28
  Speaker 1: photons can eventually produce neutrinos, but not directly. I think
• 36:31
  Speaker 1: what I'm getting here is that if you are a
• 36:33
  Speaker 1: person who likes rules and memorizing rules, then particle physics
• 36:38
  Speaker 1: is for you. And we've got fewer rules than like
• 36:41
  Speaker 1: organic chemistry. You know, we're trying to keep it simple.
• 36:45
  Speaker 1: That's true that organic chemistry is all rules, and that
• 36:48
  Speaker 1: it's just a list of rules that nobody understands and
• 36:50
  Speaker 1: it's an exception for every single case. That's that's why
• 36:53
  Speaker 1: I didn't do organic chemistry. Didn't see what I mean
• 36:55
  Speaker 1: because the list is shorter. That's the only difference. Actually,
• 37:00
  Speaker 1: totally Pegg, dude, I'm interested in particle physics because it
• 37:02
  Speaker 1: has the smallest list of things to memorize. Did I
• 37:05
  Speaker 1: ever tell you why I became an engineer? No, because
• 37:08
  Speaker 1: you wanted to work with cockroaches. Because my dad said
• 37:12
  Speaker 1: to me in high school, He's like, engineering is the best. Man.
• 37:15
  Speaker 1: You don't have to memorize anything. If anyone asks you
• 37:18
  Speaker 1: a question, you just look it up in a book.
• 37:20
  Speaker 1: And I was like, that's for me when your classes
• 37:23
  Speaker 1: or when your homeworkers due or no to turn out,
• 37:27
  Speaker 1: you don't need those things either. Um, but maybe we
• 37:32
  Speaker 1: should just round it up with my favorite rule of
• 37:34
  Speaker 1: particle decay. Okay, okay, you have a favorite favorite is
• 37:37
  Speaker 1: that a particle cannot decay into one other particle has
• 37:40
  Speaker 1: to decay into at least two. Yeah. You can't just
• 37:43
  Speaker 1: have like a Higgs Boson decay into a bottom cork,
• 37:47
  Speaker 1: or you can't even just have like a Muon decay
• 37:50
  Speaker 1: into an electron. Why not? We're not exactly sure why not,
• 37:54
  Speaker 1: but we know that if it could happen, it would
• 37:56
  Speaker 1: break another rule, which is conservation of momentum. Imagine you
• 38:00
  Speaker 1: have a heavy particle it's just sitting there, has no momentum,
• 38:04
  Speaker 1: and it turns into a lower mass particle. Now, now
• 38:07
  Speaker 1: that energy that from the difference in mass has to
• 38:10
  Speaker 1: go somewhere, and usually that goes into the motion of
• 38:12
  Speaker 1: the particle. Okay, So if a muon, for example, turned
• 38:15
  Speaker 1: into an electron, there's extra energy there from the mass difference,
• 38:19
  Speaker 1: so the electron is moving. But then that violates conservation
• 38:22
  Speaker 1: the momentum because the muon originally had no momentum and
• 38:25
  Speaker 1: now the electron has momentum. So you have to create
• 38:27
  Speaker 1: another particle to balance out the momentum that the electron
• 38:31
  Speaker 1: is getting to go the other direction. But wait, what
• 38:33
  Speaker 1: if the muan, the first one, was moving a little bit,
• 38:38
  Speaker 1: can it decay to a smaller particle that's moving faster,
• 38:41
  Speaker 1: because then you can still conserve momentum. They can't because
• 38:44
  Speaker 1: there's some of potentially some observers moving to the same
• 38:47
  Speaker 1: speed as the muan, and they also need to see
• 38:50
  Speaker 1: something that makes sense. And so that's true for all
• 38:52
  Speaker 1: particles that have mass, that there's always the potential to
• 38:55
  Speaker 1: catch up to it and see it motionless. And so
• 38:58
  Speaker 1: you have to have a rule that works also for
• 39:00
  Speaker 1: those observers. You can always look at it in a
• 39:03
  Speaker 1: way that had that it has zero momentum because it's
• 39:06
  Speaker 1: not moving. And in that frame where has no momentum,
• 39:09
  Speaker 1: it can't just spontaneously turn into an electron that's moving,
• 39:13
  Speaker 1: because then you've created momentum. And conservation momentum is another
• 39:17
  Speaker 1: one of those rules about the universe. We don't know
• 39:19
  Speaker 1: why it exists. Um, we don't know why it's there.
• 39:22
  Speaker 1: We show a whole podcast episode about these rules because
• 39:25
  Speaker 1: they're really fascinating, and they highlight a famous woman in
• 39:28
  Speaker 1: physics who has long been overlooked, Emily Nurther, who invented
• 39:32
  Speaker 1: sort of the symmetry that that describes all these things.
• 39:35
  Speaker 1: H interesting. Well, I feel like you're saying that every
• 39:39
  Speaker 1: particle is that a stand still for somebody, every particle
• 39:43
  Speaker 1: that has mass. Yes, photons are never to stand still
• 39:46
  Speaker 1: because they have no mass and if they were to
• 39:48
  Speaker 1: stand still, they'd be nothing. Okay, So you always need
• 39:51
  Speaker 1: to decay to two particles because everything is particles, right,
• 39:55
  Speaker 1: even sort of like energy? Whoa man? That was deep?
• 40:01
  Speaker 1: Did I tell you I didn't have a banana today?
• 40:03
  Speaker 1: So I am running on fubes man, everything is energy
• 40:06
  Speaker 1: and energy particles. Let's go with that. You're like, let
• 40:11
  Speaker 1: me take a puff here? Yeah, man, what did you said?
• 40:16
  Speaker 1: Go for it? I'm smoking my banana appeals. But it's
• 40:21
  Speaker 1: I think it's fascinating that every particle when it decays
• 40:23
  Speaker 1: has to turn into two others. It can't just turn
• 40:25
  Speaker 1: into one. That means that the number of particles increases,
• 40:29
  Speaker 1: so there's no conservational rule and like the overall number
• 40:32
  Speaker 1: of particles in the universe, that's not a problem, all right,
• 40:34
  Speaker 1: Maybe just to wrap it all up then, um, you know,
• 40:37
  Speaker 1: I feel like we started off with the question why
• 40:40
  Speaker 1: do particles die? And I feel like I feel like
• 40:44
  Speaker 1: we arrived at a good answer. You know, I feel
• 40:46
  Speaker 1: like it what is the meaning of last of particles
• 40:49
  Speaker 1: or two? It's it's like, that's the way the universe is,
• 40:55
  Speaker 1: you know, nothing, Um, most particles don't last forever. You know.
• 41:00
  Speaker 1: That's just the way. That's a constant truth truth of
• 41:02
  Speaker 1: the universe, unless you're you get to the bottom rung,
• 41:06
  Speaker 1: in which case you can last forever. You can last, right,
• 41:09
  Speaker 1: you can hang on forever at that bottom rung. But yeah,
• 41:12
  Speaker 1: the universe just likes to spread out. That's what it
• 41:14
  Speaker 1: means for time to move forwards in some sense is
• 41:17
  Speaker 1: that pockets of energy density spread out and diffused themselves
• 41:21
  Speaker 1: across the universe. The whole universe is spreading out and
• 41:23
  Speaker 1: getting colder and more dilute, and so the same thing
• 41:26
  Speaker 1: happens on the particle level. So in that way, we
• 41:29
  Speaker 1: have that in common with particles. And I think it's
• 41:31
  Speaker 1: amazing to think about that, the idea that every particle
• 41:35
  Speaker 1: in my body, like every single one potentially or most
• 41:38
  Speaker 1: of them, they were all there at the Big Bang, right,
• 41:42
  Speaker 1: and maybe part with the Big Bang? Is that true? No,
• 41:45
  Speaker 1: we think they were. That matter was created just after
• 41:48
  Speaker 1: the Big Bang. Oh, I see, okay, so it was
• 41:50
  Speaker 1: there in the Big Bang. All of these particles that
• 41:52
  Speaker 1: are made out of the journey fourteen billion years just
• 41:58
  Speaker 1: for the privilege of being part me. And I hope
• 42:02
  Speaker 1: they're not disappointed. Yeah, I hope this is not their
• 42:05
  Speaker 1: peak moment here. You know, they've been in the heart
• 42:08
  Speaker 1: of stars, they've flown through the universe, but this is
• 42:11
  Speaker 1: where it is, This is where it's good. Maybe maybe
• 42:13
  Speaker 1: the answer to why particles eyes that they realized they
• 42:16
  Speaker 1: travel all this way just to be part of For
• 42:18
  Speaker 1: here sously the aspultaneously decay, because why even go on? Man. Yeah,
• 42:29
  Speaker 1: but it's cool, even if this is not their peak.
• 42:31
  Speaker 1: It's cool to think that every particle in my body
• 42:34
  Speaker 1: may be here until the end of time, right like it.
• 42:38
  Speaker 1: It was there the Big Bang, and now it's part
• 42:40
  Speaker 1: of me and it they'll still be around buzillions of
• 42:44
  Speaker 1: years into the future most likely. Yeah, because, like we've
• 42:47
  Speaker 1: talked about on this podcast several times, the thing that
• 42:49
  Speaker 1: is you is not the things that make you up.
• 42:51
  Speaker 1: It's the arrangement of those bits. Because you could take
• 42:54
  Speaker 1: your bits and rearrange them and to make a star
• 42:57
  Speaker 1: or lava or kittens. It's all the same stuff when
• 42:59
  Speaker 1: the same proportions. It's just how it's put together, so
• 43:03
  Speaker 1: you can put it together to make a whorehey, or
• 43:04
  Speaker 1: a Daniel or you know, BMW or whatever you like.
• 43:08
  Speaker 1: It's all the same stuff, and it's been around for
• 43:10
  Speaker 1: a long time, and it's gonna be here for sixty
• 43:13
  Speaker 1: two chillion years. I think what you're saying, Daniel is
• 43:15
  Speaker 1: that my particles are old, but I can be as
• 43:18
  Speaker 1: young as I want to be. That's right, That's exactly
• 43:21
  Speaker 1: what I'm saying. Your particles are fourteen billion years old,
• 43:24
  Speaker 1: but you're as fresh as a breath of air. But
• 43:26
  Speaker 1: then that that air is also made out of old particles. Yeah, precisely,
• 43:31
  Speaker 1: but we don't know, and we can tell where it's
• 43:32
  Speaker 1: been based on how it smells. All right, Well, we
• 43:35
  Speaker 1: hope you enjoyed that discussion about death, the death of particles,
• 43:39
  Speaker 1: the death and birth and rebirth sometimes of particles, and
• 43:42
  Speaker 1: the eternal life of other particles, and all the rules
• 43:44
  Speaker 1: in between. And we are struggling to understand these rules.
• 43:47
  Speaker 1: And the more we smash particles together and see the
• 43:49
  Speaker 1: rules for new particles, the more we can understand why
• 43:52
  Speaker 1: we have these rules and not those rules. And are
• 43:54
  Speaker 1: these rules really universal? And do they only exist in
• 43:56
  Speaker 1: our part of the universe or for for the particles
• 43:58
  Speaker 1: that we have seen so far. And one day we
• 44:00
  Speaker 1: hope to have a very simple, concise set of rules
• 44:03
  Speaker 1: that we totally describe everything in one line, and hopefully
• 44:06
  Speaker 1: we'll be around to explain that line. So stay tuned,
• 44:10
  Speaker 1: keep listening, subscribe and follow us on Instagram and Twitter,
• 44:13
  Speaker 1: and have a great twenty everybody. See you next time.
• 44:23
  Speaker 1: Before you still have a question after listening to all
• 44:25
  Speaker 1: these explanations, please drop us a line. We'd love to
• 44:29
  Speaker 1: hear from you. You can find us on Facebook, Twitter,
• 44:31
  Speaker 1: and Instagram at Daniel and Jorge That's One Word, or
• 44:35
  Speaker 1: email us at Feedback at Daniel and Jorge dot com.
• 44:39
  Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain
• 44:42
  Speaker 1: the Universe is a production of I Heart Radio. For
• 44:45
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• 44:52
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