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What is a Neutrino? · Daniel and Kelly’s Extraordinary Universe

• 0:07
  Speaker 1: Or Hey, did you know that there's a whole universe
• 0:09
  Speaker 1: of particles that exists all around us, passing through us,
• 0:12
  Speaker 1: and you can't feel any of it. You mean like
• 0:14
  Speaker 1: a like a ghost world. Yeah, like zillions of particles
• 0:18
  Speaker 1: and you can't see or touch or detect or really
• 0:21
  Speaker 1: could even know that they're there. So what do you
• 0:23
  Speaker 1: mean it's like a whole universe passing through me, Like
• 0:25
  Speaker 1: there's stuff but we can't see it or touch it.
• 0:28
  Speaker 1: I mean that there's a huge amount of stuff in
• 0:29
  Speaker 1: the universe that you can't detect. It's there, it's interacting,
• 0:33
  Speaker 1: it's doing things, but you can't notice it. You don't
• 0:35
  Speaker 1: only notice things with your senses. That doesn't access everything
• 0:39
  Speaker 1: in the universe. In fact, we have no idea what
• 0:41
  Speaker 1: for acting in the universe We can't see at all. Right,
• 0:44
  Speaker 1: there could be huge amounts of crazy, invisible purple monsters
• 0:47
  Speaker 1: that we can't touch and never will. Well, those that
• 0:49
  Speaker 1: can't see sometimes you know, yeah, sometimes we can see
• 0:53
  Speaker 1: a little hints of it, and that gives us a
• 0:55
  Speaker 1: clue that there are vast amounts of things happening in
• 0:57
  Speaker 1: the universe that we only rarely get to see. Whoa
• 1:01
  Speaker 1: WHOA is right. Hi, I'm je and I'm Daniel, and
• 1:19
  Speaker 1: this is Daniel and Jorge Explain the universe. The universe,
• 1:23
  Speaker 1: The Universe, the universe. Yeah, it's a podcast where we
• 1:27
  Speaker 1: try to talk about all the crazy and amazing things
• 1:30
  Speaker 1: that make up this universe we live in. We want
• 1:32
  Speaker 1: to take the whole universe, wrap it up in about
• 1:35
  Speaker 1: twenty minutes and make it digestible to you fitted inside
• 1:39
  Speaker 1: of your brain, through your ears, or you know, really,
• 1:42
  Speaker 1: maybe we could grind it up, dry it and you
• 1:44
  Speaker 1: could snort the universe. That'd be pretty That's what we
• 1:47
  Speaker 1: just say. Or however you consume your podcasts, that's very
• 1:50
  Speaker 1: important in whatever, in whatever form you smoke or snort
• 1:54
  Speaker 1: or listen to your podcasts. But on today's program, we're
• 1:57
  Speaker 1: gonna talk about something mysterious, something you can't eat, but
• 2:00
  Speaker 1: something which is all around you right now. Billions and
• 2:03
  Speaker 1: billions of them are passing through you right now. And
• 2:06
  Speaker 1: we're not talking about last night's pizza. I know. The
• 2:10
  Speaker 1: topic of today's episode is the neutrino called the ghostly particle, right,
• 2:17
  Speaker 1: that's right. Some two people call it the ghostly particle.
• 2:20
  Speaker 1: The word neutrino is Italian for little neutral one. It's
• 2:23
  Speaker 1: a nickname given to the particle well before it was discovered,
• 2:27
  Speaker 1: and it's a really weird little particle. So we thought,
• 2:29
  Speaker 1: let's break it down to explain to people what it
• 2:31
  Speaker 1: actually is, because it's a fascinating mystery. Yeah, I imagine
• 2:34
  Speaker 1: not a lot of people who have heard of I
• 2:36
  Speaker 1: mean maybe some people have heard of the neutron, but
• 2:38
  Speaker 1: the neutrino that may not be as well known. In
• 2:41
  Speaker 1: order to get a sense for what people knew about
• 2:42
  Speaker 1: the neutrino, I went out and I asked people around
• 2:45
  Speaker 1: campus that you see Irvine what they knew. So play
• 2:49
  Speaker 1: along at home, think to yourself, what do you know
• 2:51
  Speaker 1: about the neutrino? And then listen to these interviews. Here's
• 2:54
  Speaker 1: what people had to say. I don't watch about it,
• 2:57
  Speaker 1: but it's I often hear that got like a cosmic
• 3:01
  Speaker 1: some one of those cosmic race and people try to
• 3:05
  Speaker 1: detect using specialized tools. I heard of it, but I
• 3:10
  Speaker 1: don't exactly what it is. Great, I do not know
• 3:13
  Speaker 1: what that is now, um no, no, alright, I'm not
• 3:18
  Speaker 1: exactly sure. So like some kind of funk esdays and nutrition,
• 3:21
  Speaker 1: I don't know what is it? Alright? Not a popular particle. No,
• 3:25
  Speaker 1: Almost nobody on campus had any idea what the neutrina was.
• 3:29
  Speaker 1: One person thought it was some sort of fungus that
• 3:31
  Speaker 1: might grow on your toes, which you could still be
• 3:34
  Speaker 1: I mean, well, I mean, we don't know a lot
• 3:37
  Speaker 1: about it. Right well, it could have potentially contribute to fungi,
• 3:40
  Speaker 1: or you could could be accumulating in your toes right now, Daniel.
• 3:44
  Speaker 1: More likely somebody creates or just or discovers a new
• 3:47
  Speaker 1: form of fungus and names it after the neutrino right
• 3:50
  Speaker 1: after this podcast goes wild. But yeah, pretty much across
• 3:53
  Speaker 1: the board, everyone said I've never heard of this, And
• 3:55
  Speaker 1: let me tell you how deeply disappointing that is to
• 3:58
  Speaker 1: me as a particle physicist. Work you see, Irvine, and
• 4:01
  Speaker 1: let me tell you why. The reason is that the
• 4:03
  Speaker 1: guy who discovered the new trino and won the Nobel
• 4:07
  Speaker 1: Prize for it. Okay, and down at you See Irvine.
• 4:09
  Speaker 1: We have a few Nobel Prize winners. But it's not
• 4:11
  Speaker 1: like we have dozens and dozens. It's not like Berkeley
• 4:14
  Speaker 1: where they have a special parking lot for Nobel Prize winners.
• 4:17
  Speaker 1: Nobel Prize, Daniel, I do not have a Nobel Prize
• 4:20
  Speaker 1: as the recording of this podcast Breaking News, Breaking News.
• 4:25
  Speaker 1: You think that's something you would already know, because if
• 4:27
  Speaker 1: I had a Nobel Prize, I'd be wearing it around
• 4:29
  Speaker 1: my chest. Um So, so it was discovered by somebody
• 4:34
  Speaker 1: in your campus, right there, Fred Ryness. Yeah. In fact,
• 4:37
  Speaker 1: the building is now named after him. I work in
• 4:40
  Speaker 1: Ryness Hall, named after Fred Ryness, the discoverer of the
• 4:43
  Speaker 1: new Trino, and he won the Nobel Prize. This is
• 4:47
  Speaker 1: It's a pretty big deal around campus, and so you
• 4:50
  Speaker 1: think maybe somebody on campus here, you see Irvine, would
• 4:53
  Speaker 1: know that. What's one of the things that we're famous for?
• 4:56
  Speaker 1: Is it part of like the tours when people, you know,
• 4:58
  Speaker 1: people tour campuses and they say, this is where the
• 5:00
  Speaker 1: nutrina was discovered. Oh my god, don't even get me started.
• 5:03
  Speaker 1: It is part of the tour. But it drives me
• 5:05
  Speaker 1: crazy because every time they walk by my building and
• 5:08
  Speaker 1: they hear the tour and they say, oh, this is
• 5:10
  Speaker 1: the building named after Fred Ryan is so won the
• 5:12
  Speaker 1: Nobel Prize. Then they give a little spiel about the
• 5:15
  Speaker 1: neutrino and they get almost everything about it totally wrong.
• 5:18
  Speaker 1: And I'm tempted every time to step into the referende.
• 5:21
  Speaker 1: Excuse me, Actually, you're going to train our round run
• 5:25
  Speaker 1: with that voice. I love it. I know how that's
• 5:27
  Speaker 1: gonna go over. Nobody cares. But do you know I
• 5:29
  Speaker 1: feel like people visiting the campuses deserve a good explanation.
• 5:33
  Speaker 1: It might factor into their decision to go to u
• 5:35
  Speaker 1: c R. Vine. Let's record an excellent podcast about the neutrino,
• 5:39
  Speaker 1: and then it will make it required listening for all
• 5:42
  Speaker 1: the tour guides, and then I won't have to explain
• 5:44
  Speaker 1: it to every single one of them one aever. Well,
• 5:46
  Speaker 1: just just put it on a speaker. You'll stand outside
• 5:49
  Speaker 1: your building with a boom box playing the podcast, like
• 5:53
  Speaker 1: you to say anything that's right. Yeah, I definitely will
• 5:55
  Speaker 1: not get picked up by campus security to nanoseconds. Absolutely,
• 6:00
  Speaker 1: that's a great idea, Thank you, y. So let's break
• 6:07
  Speaker 1: it down. What is a neutrina all right? A neutrino
• 6:10
  Speaker 1: is a fundamental particle. What does that mean? Well, a
• 6:13
  Speaker 1: fundamental particle, as we see it, is a point in space.
• 6:17
  Speaker 1: It's a tiny dot, right, It's a place in space
• 6:20
  Speaker 1: where we think there might be electric charge, there might
• 6:23
  Speaker 1: be matter, there might be all sorts of quantum properties.
• 6:26
  Speaker 1: Other examples are the electron right or the corks. These
• 6:30
  Speaker 1: are all particles we think are not made of other
• 6:32
  Speaker 1: little particles. That's why we call them fundamental. So particles
• 6:36
  Speaker 1: are not like little balls. You're saying there's special points
• 6:38
  Speaker 1: in space. That's right. We're made out of atoms, which
• 6:40
  Speaker 1: are made out of particles and things we're made out of.
• 6:43
  Speaker 1: They're not little balls. They're actually just like little special
• 6:46
  Speaker 1: points in space. That's kind of your definition of a particle. Yeah, exactly.
• 6:50
  Speaker 1: And it's very tempting to think of particles a little
• 6:52
  Speaker 1: balls because, for example, cartoonists frea balls and slaggers. Shame
• 7:01
  Speaker 1: on them. Well, it's very difficult to draw a ball
• 7:03
  Speaker 1: that has no volume because it's literally not there. Right,
• 7:07
  Speaker 1: Any tiny point you draw is going to have a
• 7:10
  Speaker 1: left side and a right side, which means it has
• 7:12
  Speaker 1: a size right. But a particle is just a single
• 7:15
  Speaker 1: point in space. There's no extent to it. The left
• 7:18
  Speaker 1: side and the right side are at the same place
• 7:20
  Speaker 1: because there's no space there. It's a zero volume dot
• 7:24
  Speaker 1: in space with some quantum mechanical properties, electric charge, mass,
• 7:29
  Speaker 1: all sorts of stuff. So the universe is filled with
• 7:30
  Speaker 1: these little points that you call particles, and they're all different.
• 7:34
  Speaker 1: There's electrons, there, protons. The neutrino is one of these
• 7:37
  Speaker 1: particles that the universe likes to make, that's right. But
• 7:41
  Speaker 1: the proton is not one of them. Proton is not
• 7:43
  Speaker 1: a fundamental particle. Right, So let's review. You're made out
• 7:46
  Speaker 1: of atoms. Atoms have electrons and and then have a nucleus.
• 7:50
  Speaker 1: The nucleus is made out of protons and neutrons, and
• 7:53
  Speaker 1: the protons and neutrons are made out of quarks. So
• 7:56
  Speaker 1: all the atoms that build up you and me and
• 7:58
  Speaker 1: hamsters and ice cream are made out of quirks and electrons. Right.
• 8:03
  Speaker 1: So the up cork and the down cork make up
• 8:05
  Speaker 1: the proton and the neutron which gives the nucleus, and
• 8:08
  Speaker 1: the electron surrounds it. And that you can make any atom.
• 8:11
  Speaker 1: You can make uranium, you can make you know, hydrogen,
• 8:14
  Speaker 1: you can make lithium. Anything. It's just made out of
• 8:16
  Speaker 1: those three particles. So these are just things that the
• 8:19
  Speaker 1: universe likes to make. And there's not just the kind
• 8:23
  Speaker 1: that we're made out of. But there's more much more
• 8:25
  Speaker 1: than that, that's right. And uh, it's fascinating because most
• 8:29
  Speaker 1: of the stuff in the universe that we know about,
• 8:31
  Speaker 1: you know, gas and planets, whatever is made out of
• 8:33
  Speaker 1: these three particles up corks, down corks, and electrons. In fact,
• 8:37
  Speaker 1: that is the recipe for almost everything, and I was
• 8:39
  Speaker 1: thinking about it the other day. It's sort of incredible.
• 8:42
  Speaker 1: It's not just the recipe for everything, but it's everything
• 8:45
  Speaker 1: in the same proportions. That is, every atom that makes
• 8:48
  Speaker 1: up you has the same number of up corks and
• 8:51
  Speaker 1: down corks and electrons, and every atom that makes up
• 8:54
  Speaker 1: ice cream or lava or hamsters, it's the same number
• 8:57
  Speaker 1: of particles. Right, So we're getting off in a bit
• 8:59
  Speaker 1: of tangent here, but it's sort of fascinating because, I
• 9:02
  Speaker 1: mean it's like there's a similar list of ingredients in
• 9:05
  Speaker 1: the same proportions, not just similar, exactly the same. So
• 9:08
  Speaker 1: if you had a kilogram of hamsters, or a kilogram
• 9:11
  Speaker 1: of ice cream or a kilogram of Jorge, it would
• 9:14
  Speaker 1: be made out of the same particles. The only difference
• 9:17
  Speaker 1: is in the arrangement of them. I mean, some some
• 9:19
  Speaker 1: arrangements are more awesome than others. I mean, come on,
• 9:22
  Speaker 1: that's right. Ice cream is really pretty awesome. I totally.
• 9:26
  Speaker 1: The interesting thing is that, as you were saying, there
• 9:28
  Speaker 1: are other particles, right, there's not just those three particles.
• 9:31
  Speaker 1: You can make all this crazy stuff out of those
• 9:33
  Speaker 1: three particles, but there are other particles out there. And
• 9:36
  Speaker 1: that's the first mistake that's made. On the u c
• 9:38
  Speaker 1: I campus tour. They describe the newtrino as a sub
• 9:41
  Speaker 1: atomic particle, the smallest part of the atom. But the
• 9:44
  Speaker 1: neutrino is not part of the atom. It's not in there.
• 9:48
  Speaker 1: You take the atom apart, and there's only up corks,
• 9:50
  Speaker 1: down corks and electrons and neutrino. It's a particle. It's
• 9:53
  Speaker 1: in the universe, but you don't need it to make
• 9:55
  Speaker 1: hydrogen or lithium or uranium or any of the other eums.
• 10:00
  Speaker 1: But maybe they mean subpotomic in terms of its size,
• 10:02
  Speaker 1: like it's much much smaller than an atom in the
• 10:05
  Speaker 1: sense that particles have no size. That's true, yes, maybe
• 10:10
  Speaker 1: in the sense that it's false, it's true, right, Well,
• 10:14
  Speaker 1: every particle is subatomic, and from from that definition, fundamental
• 10:18
  Speaker 1: particles have no size. Yeah, but it's just as small
• 10:21
  Speaker 1: as the electron or the up cork or the down cork,
• 10:24
  Speaker 1: and then it has zero volume. But the interesting thing
• 10:26
  Speaker 1: about it is that it's not part of matter, right,
• 10:29
  Speaker 1: So it's like, why is it there? Um? But the
• 10:31
  Speaker 1: neutrino is weird in in a few ways. Right. Not
• 10:34
  Speaker 1: only does it not make up the atom, it also
• 10:36
  Speaker 1: doesn't feel a lot of the forces. Like the neutrino
• 10:39
  Speaker 1: can pass right through you without interacting. That's what we're
• 10:42
  Speaker 1: talking about, the top of the episode is that neutrinos
• 10:44
  Speaker 1: are passing through us all the time in great numbers
• 10:47
  Speaker 1: and we don't feel them at all, which isn't true
• 10:49
  Speaker 1: for electrons, right, it's a huge rain of electrons. You
• 10:52
  Speaker 1: would definitely feel them, and you would get cancer pretty quick. Yeah.
• 10:55
  Speaker 1: And it's interesting because pretty much anything has the capacity
• 10:59
  Speaker 1: to move through other things things, Right, Because if everything
• 11:01
  Speaker 1: is made out of point particles, which have zero volume
• 11:04
  Speaker 1: they're just little points in space, then technically, if you
• 11:07
  Speaker 1: take a whole bunch of nothing, you should be able
• 11:08
  Speaker 1: to pass it through another whole bunch of nothing. Right,
• 11:11
  Speaker 1: that's right, that's right exactly. So if you take a
• 11:14
  Speaker 1: bunch of point particles that don't interact with each other
• 11:17
  Speaker 1: at all, then they will pass through each other. There's
• 11:20
  Speaker 1: no chance that they will collide because they have zero volume.
• 11:23
  Speaker 1: So that's sort of overlapping area. What we call the
• 11:25
  Speaker 1: cross section particle physics is zero, right, you can't make
• 11:29
  Speaker 1: two things that have zero volume hit each other. It's vable,
• 11:32
  Speaker 1: And so yeah, you're right. You could have a huge
• 11:34
  Speaker 1: density of them and a new one can come along
• 11:36
  Speaker 1: and just pass right through it. Yeah, because like the
• 11:38
  Speaker 1: reason I can't go through the wall here, the reason
• 11:41
  Speaker 1: I can't pass through it like a ghost. It's not
• 11:43
  Speaker 1: that like my particles hit against the other particles like
• 11:47
  Speaker 1: they bump against each other. It's just like they want
• 11:50
  Speaker 1: to get closed. But then there's other forces that that
• 11:52
  Speaker 1: prevent me from going near them. Exactly. The particles that
• 11:57
  Speaker 1: make up the wall have no volume to them at all. Right,
• 11:59
  Speaker 1: It's like a it's just a bunch of dots, and
• 12:02
  Speaker 1: you're a bunch of dots, and so you should be
• 12:03
  Speaker 1: able to pass through it. Except, of course, the particles
• 12:06
  Speaker 1: that make up the wall are not just a disconnected
• 12:08
  Speaker 1: bunch of dots. They're bound very tightly together with forces,
• 12:12
  Speaker 1: and those forces hold them together into sheets and structures,
• 12:16
  Speaker 1: and also those forces repel other particles that feel those forces.
• 12:20
  Speaker 1: So when your finger is pushing against the wall, what's
• 12:23
  Speaker 1: happening is not that the ball particles in your finger
• 12:26
  Speaker 1: are bouncing off the ball particles in the wall, but
• 12:28
  Speaker 1: they're repelling each other using mostly electromagnetism. So the sensation
• 12:34
  Speaker 1: of touching things and holding things and standing on top
• 12:37
  Speaker 1: of things that it's really just like we're all kind
• 12:40
  Speaker 1: of magnets repelling each other. Yeah, they're electrostatic forces mostly
• 12:43
  Speaker 1: their chemical bonds, right. And so you can think of
• 12:46
  Speaker 1: like a surface of something is like a chain link fence, right,
• 12:49
  Speaker 1: lots of big gaps, but then there's links holding it together.
• 12:52
  Speaker 1: And you know, another chain link fence coming up to it,
• 12:55
  Speaker 1: which is also mostly air, can't pass through it because
• 12:58
  Speaker 1: they both have these links. So that's the thing is
• 13:00
  Speaker 1: that something can only touch you or affect you, or
• 13:03
  Speaker 1: you can only feel it if it's affected by electromagnetic forces.
• 13:07
  Speaker 1: That's kind of the key, right. Yeah, So there's two
• 13:09
  Speaker 1: elements of the universe, not just particles, but also forces, right,
• 13:12
  Speaker 1: and those are the basic building blocks of how we
• 13:14
  Speaker 1: do science and particle physics. We got the particles and
• 13:16
  Speaker 1: we've got the forces. I mean, another time we can
• 13:18
  Speaker 1: talk about quantum field theory. And for those listeners out
• 13:20
  Speaker 1: there who know that, you know that everything is actually
• 13:23
  Speaker 1: just a quantum field. But let's talk about particles and
• 13:25
  Speaker 1: forces today extra credit podcast. That's right. So at this
• 13:29
  Speaker 1: level that we say it's particles and they're connected by forces,
• 13:32
  Speaker 1: the forces are how the particles talk to each other.
• 13:35
  Speaker 1: And if my particles are talking to your particles, then
• 13:37
  Speaker 1: when you punch me in the face, then that's why
• 13:40
  Speaker 1: I feel it right now. If you say when, as if,
• 13:42
  Speaker 1: it happens often, I'm trying to make this a concrete
• 13:46
  Speaker 1: example for the listeners, you know, not abstract type of
• 13:48
  Speaker 1: if I slowly caress your cheek. Hold on. I noticed
• 13:53
  Speaker 1: that you made that an if, not a when. Um,
• 13:57
  Speaker 1: let's keep this PG. Imagine that you were built out
• 14:02
  Speaker 1: of particles. It felt different forces than me than when
• 14:05
  Speaker 1: we high fived. Our hands would pass right through each
• 14:08
  Speaker 1: other because those forces would not pay attention to each
• 14:10
  Speaker 1: other or tract or repell or anything. We would like
• 14:13
  Speaker 1: phase right through each other because the particles that make
• 14:16
  Speaker 1: us up don't interact, right, So it's all about interacting. Okay,
• 14:19
  Speaker 1: So the neutrino is one of these particles that doesn't
• 14:22
  Speaker 1: speak the same language that our particles speak. That's right.
• 14:26
  Speaker 1: The neutrino is neutral. It has no electric charge. That's
• 14:30
  Speaker 1: one of the reasons it's called neutrino. Neutrino is Italian
• 14:33
  Speaker 1: for little neutral particle. And so it doesn't feel electromagnetism
• 14:37
  Speaker 1: at all. And not only does it not feel electromagnetism
• 14:40
  Speaker 1: like the electron does feel it, but it also doesn't
• 14:43
  Speaker 1: feel the strong nuclear force that's the one that holds
• 14:46
  Speaker 1: the corks together in the nucleus and affects the proton
• 14:49
  Speaker 1: and the neutron. So it doesn't feel the two strongest
• 14:52
  Speaker 1: forces in the universe, the strong nuclear force and electromagnetism.
• 14:56
  Speaker 1: Generally just likes to avoid conflict. Yeah, well, it's kind
• 14:59
  Speaker 1: of snob mostly ignores everything. It's nay or shy. I
• 15:03
  Speaker 1: don't know. You could see it both ways, says the introvert,
• 15:07
  Speaker 1: right standing up for the introverted particle, aren't you. Well,
• 15:10
  Speaker 1: let's get it more into it, but let's take a
• 15:12
  Speaker 1: quick break first. Okay, So the neutrino is a particle
• 15:27
  Speaker 1: in the universe that's there. There's a lot of them
• 15:30
  Speaker 1: out there, but it just doesn't feel the same forces.
• 15:33
  Speaker 1: It doesn't speak the same language that you and I
• 15:36
  Speaker 1: and all the particles that make us speak or use right,
• 15:40
  Speaker 1: that's right. Yeah, it's like, um, you know, it's like
• 15:43
  Speaker 1: it's a it's deaf or something. You can walk through
• 15:45
  Speaker 1: the loudest bar, you know, with thump thump thump music, right,
• 15:50
  Speaker 1: and not even hear anything, not even notice it's there. Right,
• 15:52
  Speaker 1: it's not purposely ignoring you, it just does not hear it. Interesting.
• 15:56
  Speaker 1: I was thinking a good analogy could also be you
• 15:58
  Speaker 1: know how in the Internet today people communicated using Facebook
• 16:02
  Speaker 1: or Twitter, or Instagram or email. Those are all different
• 16:06
  Speaker 1: ways that people interact with each other on the Internet.
• 16:09
  Speaker 1: But what if there was somebody who said, you know what,
• 16:11
  Speaker 1: I'm not going to use Twitter or Instagram or Facebook.
• 16:14
  Speaker 1: I'm just gonna respond to people if they write me
• 16:17
  Speaker 1: a handwritten letter. That's right. Yeah, those people are social
• 16:21
  Speaker 1: media neutrinos. Yes, yeah, that's kind of what it is.
• 16:25
  Speaker 1: It's like everybody else is talking to each other in
• 16:27
  Speaker 1: one way, but this one particle just says, you know what,
• 16:30
  Speaker 1: I'm going to ignore those different ways to interact. I'm
• 16:33
  Speaker 1: just gonna do my thing. Yeah, and given the toxicity
• 16:35
  Speaker 1: of social media, that probably means the neutrino is the
• 16:38
  Speaker 1: happiest particle. Yeah, you know, they made. That's the key
• 16:42
  Speaker 1: we should all learn from newtrinos. Yeah. Um, So let's
• 16:45
  Speaker 1: remind people though, what the forces are. So there's the
• 16:48
  Speaker 1: strong nuclear force that ties the nucleus together. There's electromagnetism
• 16:52
  Speaker 1: that's responsible for electricity and magnetism and light and all
• 16:55
  Speaker 1: that kind of stuff. And then there's the weak nuclear
• 16:58
  Speaker 1: force that's the weakest of of these forces. And then
• 17:01
  Speaker 1: there's gravity. Everything with mass feels gravity, right, but in
• 17:05
  Speaker 1: the case of particles, we don't really think about gravity
• 17:07
  Speaker 1: very much because particles have hardly any mass at all,
• 17:10
  Speaker 1: and so gravity doesn't really affect them to really those
• 17:12
  Speaker 1: other three. So the corks, the corks, they feel the
• 17:15
  Speaker 1: strong nuclear force and electromagnetism and the weak force. Okay,
• 17:20
  Speaker 1: so they feel everything. Electrons, they feel electromagnetism, and they
• 17:25
  Speaker 1: feel the weak nuclear force. Neutrinos only feel the weak
• 17:29
  Speaker 1: nuclear force, which is called the weak nuclear force because
• 17:32
  Speaker 1: it's super duper weak, not because it takes a week
• 17:35
  Speaker 1: to act or something like that. So it doesn't just
• 17:37
  Speaker 1: ignore some of the forces that everybody else fields, but
• 17:41
  Speaker 1: it only it's like the one it chose to interact
• 17:44
  Speaker 1: with the rest of the universe is like the week
• 17:46
  Speaker 1: is one. It's like the most incossequential one, right exactly.
• 17:50
  Speaker 1: It's like, you know, if you could only interact with
• 17:52
  Speaker 1: somebody by sending them a letter to the south pole,
• 17:54
  Speaker 1: and the letters only go every six months or something, right,
• 17:57
  Speaker 1: And you know, if the neutrino didn't feel any forces
• 18:00
  Speaker 1: at all, then we would have no way to even
• 18:02
  Speaker 1: know it existed. There could be a whole set of
• 18:05
  Speaker 1: particles that speak even maybe a whole different set of forces. Yeah,
• 18:09
  Speaker 1: like people think about dark matter, right, dark matter, we
• 18:12
  Speaker 1: don't know if it feels any of these forces, and
• 18:14
  Speaker 1: that's what makes it so difficult to look for and
• 18:16
  Speaker 1: to understand. Dark amount, as far as we know, only
• 18:18
  Speaker 1: speaks gravity, which is why you can only study it
• 18:21
  Speaker 1: when there's like a galaxy sized blob of it. Neutrinos
• 18:25
  Speaker 1: do feel one of these forces, which is why we
• 18:27
  Speaker 1: can talk about them and study them. Well, let's talk
• 18:29
  Speaker 1: about some of these properties that I was reading about
• 18:32
  Speaker 1: the neutrino. I read that it has a mass that's
• 18:35
  Speaker 1: maybe one less than one million of the mass of
• 18:38
  Speaker 1: the electron. That's right. Neutrinos are super duper duper low mass,
• 18:42
  Speaker 1: and we don't understand why at all. You know, we
• 18:45
  Speaker 1: look at the mass of these particles, the electron, the corks,
• 18:48
  Speaker 1: the other ones. We have no idea why these particles
• 18:50
  Speaker 1: are different masses. We did a whole episode on how
• 18:53
  Speaker 1: they get their masses, which is about interacting with the
• 18:55
  Speaker 1: Higgs boson. Some of them interact a lot with the
• 18:57
  Speaker 1: Higgs boson and so they get a lot of mass,
• 18:59
  Speaker 1: and some them don't interact hardly at all, so they
• 19:01
  Speaker 1: get almost no mass. But we don't know why, Like,
• 19:04
  Speaker 1: why does this one interact with the Higgs a lot
• 19:06
  Speaker 1: and this one almost none. It's like a bunch of
• 19:08
  Speaker 1: parameters in the control panel the universe, and we don't
• 19:11
  Speaker 1: know if there's a pattern to it, or if they
• 19:12
  Speaker 1: just set randomly at the beginning of the universe. We
• 19:15
  Speaker 1: have no clue, but it seems like an important hint
• 19:18
  Speaker 1: that the neutrinos are so close to zero mass but
• 19:22
  Speaker 1: not actually zero. Yeah, so they are kind of tiny, right,
• 19:26
  Speaker 1: I mean, I know everything is a point mass mathematically,
• 19:28
  Speaker 1: but these things, I mean they're not just a point mass,
• 19:31
  Speaker 1: but they're a point mass that are really really really
• 19:34
  Speaker 1: really really almost no mass. That's right. But if again,
• 19:37
  Speaker 1: it doesn't affect their size right. Their physical size is
• 19:41
  Speaker 1: a different thing from their mass. Their mass is like
• 19:43
  Speaker 1: a quantum mechanical label, like electric charge. Right, it's not
• 19:47
  Speaker 1: like something with more mass. It is more stuffed to it.
• 19:49
  Speaker 1: But yeah, you're right. Neutrinos are weird because they have
• 19:51
  Speaker 1: almost no mass but not zero, like they're not the
• 19:54
  Speaker 1: lightest thing in the universe though. Right. Photons have no
• 19:57
  Speaker 1: mass exactly zero. They travel to speed of light. Neutrinos
• 20:01
  Speaker 1: just less than the speed of light because they have
• 20:03
  Speaker 1: just more than zero mass. These particles only choose to
• 20:08
  Speaker 1: interact with the rest of the universe using the weak force.
• 20:11
  Speaker 1: And the weak force is not just weak, but it's
• 20:14
  Speaker 1: also really short, meaning that it doesn't work over long distances.
• 20:19
  Speaker 1: You have to be within the diameter of a proton
• 20:23
  Speaker 1: just to feel this force. That's right. The weak force
• 20:26
  Speaker 1: is super limited, right, And not only is it weak,
• 20:29
  Speaker 1: as you're saying, but it's short range. And the reason
• 20:32
  Speaker 1: is that the particles that communicate that force. Remember, we
• 20:35
  Speaker 1: have particles that make up matter, and then we also
• 20:37
  Speaker 1: have forces, and the forces themselves are communicated using particles. So,
• 20:41
  Speaker 1: for example, electromagnetism is communicated using the photon, right, And
• 20:46
  Speaker 1: electromagnetism goes everywhere in the universe has infinite range, and
• 20:49
  Speaker 1: the reason is that the photon is massless. Right, the
• 20:52
  Speaker 1: photon has no mass. But the particles that communicate the
• 20:55
  Speaker 1: weak force, they're called the w and the z bosons
• 20:58
  Speaker 1: are really really v particles, sort of ironic. The lightest
• 21:02
  Speaker 1: particle of all the matter particles in neutrino uses the
• 21:06
  Speaker 1: heaviest force particles, which means that they don't go very far.
• 21:09
  Speaker 1: So this particle not only is it um ignoring a
• 21:14
  Speaker 1: lot of the forces, but the forces that it does
• 21:16
  Speaker 1: feel are super weak. And this particle is super light.
• 21:19
  Speaker 1: It's almost like it's almost not there, you know, like
• 21:23
  Speaker 1: what is the not at all? Not at all? In fact,
• 21:26
  Speaker 1: there's zillions of neutrinos. I mean, it's not there in
• 21:29
  Speaker 1: the sense that you can almost not tell that it's there.
• 21:31
  Speaker 1: But there are a huge number of neutrinos. Like if
• 21:34
  Speaker 1: you hold out your fingernail, it's approximately one square centimeter.
• 21:38
  Speaker 1: There are a hundred billion neutrinos passing through your fingernail
• 21:43
  Speaker 1: every second. D yes ten to the eleven neutrinos per
• 21:49
  Speaker 1: square centimeter per second. Let's count. So look at your
• 21:52
  Speaker 1: fingernail one one, two, three hundred billion neutrinos just went
• 22:00
  Speaker 1: in my fingernail, that's right, and ignored you. Right, And neutrinos,
• 22:04
  Speaker 1: I mean, not only can we not detect them, they
• 22:06
  Speaker 1: can't really detect us right to them, we are like
• 22:09
  Speaker 1: an invisible haze in the universe. Right then, don't even
• 22:12
  Speaker 1: know where I would exist, right, They hardly interact with.
• 22:15
  Speaker 1: A neutrino interact with the rest of the universe so
• 22:17
  Speaker 1: weakly that it can pass right through the Earth without interacting. Again,
• 22:22
  Speaker 1: not because it's small. It's not that it like wiggles
• 22:25
  Speaker 1: through cracks between atoms, right, It's that it doesn't interact.
• 22:29
  Speaker 1: It just doesn't care. It just yeah, it just flies
• 22:31
  Speaker 1: right through. Um. A neutrino can pass through a light
• 22:34
  Speaker 1: year of lead. Okay, So imagine a blob of lead
• 22:38
  Speaker 1: that's a light year long, which is how far light
• 22:40
  Speaker 1: travels any year, which is really really far, and lead
• 22:44
  Speaker 1: it's a really kind of like dense metal. Right, Yeah,
• 22:47
  Speaker 1: it's a huge amount of stuff. Right. Um, neutrino can
• 22:50
  Speaker 1: pass through a wall that thick and have about a
• 22:52
  Speaker 1: fifty percent chance of interacting. So it's just going through
• 22:56
  Speaker 1: the universe doing its own thing. Yeah, making us feel
• 22:59
  Speaker 1: even more insignificant. It's all about you, Jorge, It's all
• 23:04
  Speaker 1: about you. It's something insignificant. Is making us feel even
• 23:07
  Speaker 1: more insignificant. Well, we are pretty insignificant. Nothing we do
• 23:12
  Speaker 1: is important. Um, But it turns out that neutrinos are
• 23:16
  Speaker 1: not just ignoring us, they're also ignoring the whole Earth
• 23:19
  Speaker 1: and other suns and everything. And you might be asking, like,
• 23:23
  Speaker 1: why are there so many neutrinos? Where are they coming from?
• 23:26
  Speaker 1: And the answer is that they come from the Sun.
• 23:28
  Speaker 1: They're produced in the fusion reaction at the core of
• 23:31
  Speaker 1: the Sun. Well, I think the question that I want
• 23:33
  Speaker 1: to know is, if they're so light, so inconsequential, so ignoring,
• 23:38
  Speaker 1: how do we even know that it's there? And why
• 23:40
  Speaker 1: should we even care that it's there? All right? Great,
• 23:43
  Speaker 1: great question? How do we know that it's there? Well,
• 23:46
  Speaker 1: it does interact, right, so it can interact with our world.
• 23:50
  Speaker 1: And because there are so many of them, the big
• 23:53
  Speaker 1: number of how many there are and the small number
• 23:55
  Speaker 1: of the probability of them to interact actually balance out
• 23:58
  Speaker 1: to give us a reasonable number of times. And neutrinos
• 24:02
  Speaker 1: do interact with normal matter. And so if you set
• 24:04
  Speaker 1: up a big experiment. You can catch neutrinos right, because
• 24:08
  Speaker 1: there's a huge number of them. So out of the
• 24:10
  Speaker 1: hundreds of billions fault flowing through my fingernail, every once
• 24:14
  Speaker 1: in a while, one mom would be like, oh, hey,
• 24:16
  Speaker 1: what's this. It's a fingernail exactly. I don't know what
• 24:19
  Speaker 1: a fingernail is, but I just ran into it. Yeah.
• 24:22
  Speaker 1: So what you do if you want to catch new
• 24:23
  Speaker 1: trinos is you set up a big vat, for example,
• 24:27
  Speaker 1: of water underground, and you shield it from everything else,
• 24:30
  Speaker 1: so you make sure you don't get any background from
• 24:32
  Speaker 1: muans or anything else crazy, and you wait until one
• 24:35
  Speaker 1: of those atoms of water and gets bumped by something mysterious,
• 24:39
  Speaker 1: and there are ways to tell whether or not it
• 24:41
  Speaker 1: was bumped by something like a neutrino. And that's the
• 24:43
  Speaker 1: way that we measure neutrinos. Today. We have these huge detectors,
• 24:46
  Speaker 1: like the ones called super Comioconda in Japan that measure
• 24:49
  Speaker 1: neutrinos from the Sun and from other sources. And they
• 24:52
  Speaker 1: do about having these big tanks of heavy water and
• 24:54
  Speaker 1: waiting for one of them to get bumped by neutrino.
• 24:58
  Speaker 1: So that's how we know where they were there, like,
• 25:00
  Speaker 1: can definitely see them, You can definitely see them interacting. Yeah,
• 25:03
  Speaker 1: and that's how fred Ryan saw them. He signed neutrinos
• 25:06
  Speaker 1: bouncing off of protons and turning into a very characteristic
• 25:10
  Speaker 1: signal that you couldn't mimic with anything else. And so
• 25:12
  Speaker 1: I mean in that sense, he doesn't see the neutrinos
• 25:14
  Speaker 1: themselves directly. It's not like he captured one, put it
• 25:17
  Speaker 1: in the box, said ah ha, look here's my Nobel
• 25:19
  Speaker 1: Prize winning discovery. What he saw was something that happened
• 25:23
  Speaker 1: that only a neutrino could do. Well, I have more questions,
• 25:27
  Speaker 1: but let's take a quick break. So, I think a
• 25:42
  Speaker 1: lot of particle physics laboratories in the country and across
• 25:45
  Speaker 1: the world. Now there's kind of a renewed interest in
• 25:47
  Speaker 1: neutrinos now that we found the Higgs boson and and
• 25:50
  Speaker 1: a lot of these particles in the standard model of physics.
• 25:54
  Speaker 1: There's a lot of interest down the netrino. So why
• 25:56
  Speaker 1: is that, Well, why is the neutrino interesting or why
• 25:59
  Speaker 1: is it a big deal? Yeah, it's a big deal,
• 26:01
  Speaker 1: and not just because it's weird, but one of the
• 26:04
  Speaker 1: things we want to do in particle physics is understand
• 26:07
  Speaker 1: the universe at its smallest scale, right, understand the tiniest
• 26:10
  Speaker 1: little bits. And to do that, we need to look
• 26:12
  Speaker 1: not just at the kind of matter that makes us up,
• 26:14
  Speaker 1: but the kind of matter that's everywhere in the universe.
• 26:16
  Speaker 1: Because we're looking for ideas and patterns that go bigger
• 26:20
  Speaker 1: than humanity, right, that that are tell us something fundamental
• 26:23
  Speaker 1: and deep about the universe. So for that we need
• 26:26
  Speaker 1: to cast our net as widely as possible and understand
• 26:29
  Speaker 1: how this kind of matter works, how other kinds of
• 26:31
  Speaker 1: matter works. And so it's important to understand neutrinos because
• 26:34
  Speaker 1: they are there their clue somehow about how the universe
• 26:37
  Speaker 1: is put together. Right, And it could be and I said,
• 26:40
  Speaker 1: neutrinos are fundamental, that they're not made of other things.
• 26:43
  Speaker 1: That's our current state of knowledge. It could be the
• 26:45
  Speaker 1: neutrinos and corks and electrons and every particle we know
• 26:49
  Speaker 1: are actually made out of something smaller neutrinos. Neutrinos. To
• 26:55
  Speaker 1: answer your question, why should we study them, Well, they
• 26:58
  Speaker 1: give us clues as to how the whole principles working together. Right.
• 27:01
  Speaker 1: We wanted to get the big picture so we can
• 27:03
  Speaker 1: see all the patterns because those patterns give us clues
• 27:05
  Speaker 1: as to what's going on to underneath, what these things
• 27:07
  Speaker 1: are all made out of, and what the answers are.
• 27:09
  Speaker 1: But also because neutrinos themselves are really weird. They can
• 27:13
  Speaker 1: do things that other particles can't, Like they can change
• 27:16
  Speaker 1: from one type into the other. You know, for example,
• 27:18
  Speaker 1: an electron is an electron is an electron. It's never
• 27:21
  Speaker 1: going to change into a muan, but an electron neutrino.
• 27:25
  Speaker 1: Neutrinos come in three different flavors electron, muon, and taw.
• 27:29
  Speaker 1: They can switch from one to the other. So you
• 27:31
  Speaker 1: create one type in the Sun and as it's flying
• 27:35
  Speaker 1: to the Earth that has about a one third chance
• 27:37
  Speaker 1: to change into another kind of neutrino. That's really strange.
• 27:40
  Speaker 1: It's not something we've seen before, and it actually breaks
• 27:43
  Speaker 1: a pretty basic rule in the standard model of particle
• 27:46
  Speaker 1: physics that you can't switch from one kind of flavor
• 27:49
  Speaker 1: to another. So we don't know why that is when,
• 27:51
  Speaker 1: don't know what it means. Lots of possibilities. It's like
• 27:54
  Speaker 1: it's not only ignoring Twitter and Facebook and Instagram, it's
• 27:57
  Speaker 1: changing its address every three months, like it really doesn't
• 28:01
  Speaker 1: want to be found. That's right. Yeah, it's a pretty
• 28:04
  Speaker 1: weird little particle can do all sorts of things, and
• 28:06
  Speaker 1: so we're hoping that figuring out what he can do
• 28:08
  Speaker 1: and how it interacts and nailing down all these details
• 28:11
  Speaker 1: will give us a clue as to some of the
• 28:13
  Speaker 1: deeper mysteries. You know, how did all the matter come
• 28:15
  Speaker 1: to be? Why do we have the matter or not antimatter?
• 28:18
  Speaker 1: What are all these things made out of? We're hoping
• 28:20
  Speaker 1: that just nailing down and tying up the loose ends
• 28:22
  Speaker 1: and new trinos gives us clues to answer these other bigger,
• 28:25
  Speaker 1: deeper questions, because that's kind of how science works, you know, right.
• 28:29
  Speaker 1: I mean, science doesn't just study human beings and our biology.
• 28:33
  Speaker 1: Science also studies other animals and other organisms, because that
• 28:37
  Speaker 1: tells us a lot about why we're here, or what
• 28:39
  Speaker 1: the rules are for why we're here. Yeah, exactly exactly.
• 28:42
  Speaker 1: To understand humanity, you understand all of our closest cousins
• 28:45
  Speaker 1: and our distant relatives and the whole spectrum of life
• 28:48
  Speaker 1: on Earth to get the context. And so we want
• 28:50
  Speaker 1: to understand how particles work. We want to we need
• 28:52
  Speaker 1: to study all of them. Yeah, I mean, the weird
• 28:54
  Speaker 1: ones that don't want to be found. That's right, We're
• 28:57
  Speaker 1: going to ignore all of their preferences and study him anyway. Yeah,
• 29:01
  Speaker 1: I'm not a particle physicist. I'm a particle stalker. Yeah,
• 29:04
  Speaker 1: particle hunter. Isn't that what they sometimes they call you guys,
• 29:07
  Speaker 1: particle hunters? Particle hunters? Yeah, look, I found one, this
• 29:10
  Speaker 1: one right here. So what do you think learning about
• 29:16
  Speaker 1: this ghostly particle is going to teach us? Like, what
• 29:19
  Speaker 1: are the possibilities of things we can learn from it? Well,
• 29:21
  Speaker 1: we could learn that there are other kinds of particles
• 29:24
  Speaker 1: out there. Some people think that there might be four
• 29:26
  Speaker 1: kinds of neutrinos out there. There's a new kind of
• 29:29
  Speaker 1: of neutrino called the sterile neutrino, which doesn't even feel
• 29:32
  Speaker 1: the weak force. Right, people think that there there might
• 29:35
  Speaker 1: be this other kind of particle out there. Um, it
• 29:38
  Speaker 1: might tell us something about why we have matter and
• 29:40
  Speaker 1: antimatter because it it might be related to how things
• 29:43
  Speaker 1: switch back and forth. Um. But most likely I think
• 29:46
  Speaker 1: it's going to contain some surprises. You know, particle physics,
• 29:49
  Speaker 1: the history of us has been full of surprises. Do
• 29:51
  Speaker 1: you think think this is happening? Turns out bad's happening,
• 29:54
  Speaker 1: and the only way to dig into it is to
• 29:55
  Speaker 1: just explore, dig into it and figure it out and
• 29:58
  Speaker 1: see what nature has to tell us. The asked, he
• 30:00
  Speaker 1: would be neutral. That's right. And so I hope after
• 30:04
  Speaker 1: listening to this episode those folks out there, I'll know
• 30:07
  Speaker 1: now what a neutrino is. That's not a fungus on
• 30:09
  Speaker 1: your toneail, and that it's a tiny particle. Yes, And
• 30:12
  Speaker 1: also it was that it was discovered in the campus
• 30:15
  Speaker 1: of UC Berkeley, Irvine, UC Irvine. That's wait, it's not
• 30:19
  Speaker 1: UC Berkeley. Actually you know that. You just said that
• 30:25
  Speaker 1: to Ryan me up. All right, Well, thank you for
• 30:28
  Speaker 1: joining us. See you next time. Another piece of the
• 30:30
  Speaker 1: universe explained before. You still have a question after listening
• 30:42
  Speaker 1: to all these explanations, please drop us a line. We'd
• 30:45
  Speaker 1: love to hear from you. You can find us at Facebook, Twitter,
• 30:48
  Speaker 1: and Instagram at Daniel and Jorge that's one word, or
• 30:52
  Speaker 1: email us at Feedback at Daniel and Jorge dot com.