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What is the axion? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Daniel, if you ever discovered a particle, what would
0:12
Speaker 1: you name it? Oh? I feel a little bit put
0:15
Speaker 1: on the spot and no pressure. I mean, you wouldn't
0:17
Speaker 1: just name it the white sun or the white cuno, did, DANIELO. Well,
0:22
Speaker 1: you know, over the course of these podcasts, I've come
0:24
Speaker 1: to get a feeling of, I don't know, judgment from
0:27
Speaker 1: you by the quality of particle names. So I guess
0:30
Speaker 1: I feel some responsibility to like do it right and
0:33
Speaker 1: meet your high standards. Well, I'm glad I'm doing my
0:36
Speaker 1: bid to make physics better. You know. I just hope
0:39
Speaker 1: you don't give it a silly name, you know, like
0:40
Speaker 1: a random name, like a squiggly on or something. You know,
0:43
Speaker 1: those quiglyons. That would be a silly name. Well, I
0:46
Speaker 1: promised to do my best. I won't like name it
0:49
Speaker 1: after a random laundry detergent or something. All right, if
0:52
Speaker 1: you do that, this podcast is over. Hi am Orhammad,
1:10
Speaker 1: cartoonist and the creator of PhD comics. Hi. I'm Daniel.
1:14
Speaker 1: I'm a particle physicist who has never discovered a particle,
1:17
Speaker 1: at least one that nobody else has discovered. That's right.
1:20
Speaker 1: I found particles this morning when I had breakfast and
1:23
Speaker 1: I planned to find some more for lunch. But they're
1:25
Speaker 1: all your everyday running the mill quirks and electron Yeah,
1:28
Speaker 1: I find particles all the time in my belly button.
1:33
Speaker 1: That's probably not a picture we want to paint this
1:35
Speaker 1: really in the episode. That's probably what dark matter is. Jorge.
1:38
Speaker 1: It's just your belly button. Oh yeah, my billy win
1:40
Speaker 1: is full of dark matter and dark energy and physicists
1:45
Speaker 1: also can't explain it. But welcome to our podcast, Daniel
1:48
Speaker 1: and Jorge Explain the Universe, a production of I Heart
1:51
Speaker 1: Radio in which we try to tackle the biggest questions
1:54
Speaker 1: in the universe. What is dark matter, what is everything
1:56
Speaker 1: made out of? What is that weird thing in Jorge's
1:59
Speaker 1: belly button? And we try to do it in a
2:01
Speaker 1: way that educates you and entertains you along the way.
2:04
Speaker 1: And we like to talk about not just the science
2:06
Speaker 1: and what we know about the universe and what we
2:08
Speaker 1: don't know, but we also kind of like to talk
2:11
Speaker 1: sometimes about the process of science, like how are things
2:13
Speaker 1: discovered or what are scientists thinking about or what are
2:17
Speaker 1: they looking for. That's right, because the forefront of science,
2:19
Speaker 1: the edge of human curiosity, it belongs to everybody, and
2:23
Speaker 1: we want you to know what are scientists thinking about,
2:26
Speaker 1: what are they wondering about, what do they not know?
2:28
Speaker 1: And what are they doing to figure it out? How
2:30
Speaker 1: do we go from clueless too, slightly clued in, slightly
2:34
Speaker 1: less clueless, diminishing cluelessness. That'll be the title of my autobiography. Yeah,
2:39
Speaker 1: we would like to kind of stand at the precipice
2:42
Speaker 1: of ignorance. I'd like to call it like, we're right
2:44
Speaker 1: at the edge of what scientists know and don't know
2:47
Speaker 1: and what they're discovering right now at the moment. Do
2:49
Speaker 1: you think we are in danger of falling into that
2:51
Speaker 1: precipice or we're pushing it back. I think it's possible
2:54
Speaker 1: to go a little bit too deep into the rabid
2:57
Speaker 1: hole here of what we don't know in physics. Just
3:00
Speaker 1: following up on your metaphor there, does that make the
3:02
Speaker 1: rabbit is ignorance or rabbits are ignorant? Well, I don't
3:07
Speaker 1: want to insult any rabbits. We're definitely pro rabbit on
3:10
Speaker 1: this podcast. Were we are we like rabbits here? But
3:14
Speaker 1: you know, one question is that you know there are
3:16
Speaker 1: all these particles out there in the universe and there's
3:19
Speaker 1: a whole bunch of particles we've discovered in the universe,
3:22
Speaker 1: and and so the kind of the question is like,
3:24
Speaker 1: how do people find new particles? How do you physicists
3:27
Speaker 1: discover them? Yeah, there's sort of two big ways to
3:30
Speaker 1: do it. One is to look at the list of
3:31
Speaker 1: particles we have now and say it doesn't seem complete.
3:35
Speaker 1: We need another one. And this is the case when
3:38
Speaker 1: we talked about the top cork, for example, we had
3:40
Speaker 1: a nice little pattern of particles with a missing square
3:43
Speaker 1: in it. There was one particle that didn't have a
3:45
Speaker 1: partner and everything else was paired off, so we thought
3:48
Speaker 1: there must be one there. And sometimes, more abstractly, we
3:51
Speaker 1: say there's just a larger pattern that would make sense
3:54
Speaker 1: if we added one more particle. That's how the Higgs
3:57
Speaker 1: boson was discovered, for example. So you're saying particle physics,
3:59
Speaker 1: it's it's kind of like pokemon collecting or baseball card collecting. Yeah,
4:04
Speaker 1: except we can't trade. You know, if the aliens come,
4:07
Speaker 1: maybe we could trade our discoveries for their for theirs. Right,
4:10
Speaker 1: Oh my goodness, your nerve brain just exploded. I'll give
4:13
Speaker 1: you a Higgs boson for the dark matter. Please? Do
4:15
Speaker 1: you have dark matter? We want dark matter? Boy? That
4:20
Speaker 1: would be uh, that does sound kind of like fun.
4:22
Speaker 1: You know, you can get together the neighborhood and you
4:25
Speaker 1: exchange what do you know about the universe. I'm looking
4:28
Speaker 1: forward at that party. But there's a whole other way
4:30
Speaker 1: to discover particles, which is just to sort of stumble
4:33
Speaker 1: across them, to like find them in nature and see
4:36
Speaker 1: them and go what's that and then figure out how
4:39
Speaker 1: does it fit into the larger puzzle, where does this go?
4:42
Speaker 1: How do we connected? And we haven't done too much
4:45
Speaker 1: of that recently. Mostly we've been predicting particles and then
4:48
Speaker 1: find I see. So how would you stumble upon a
4:50
Speaker 1: particle like you're running the collider or any kind of
4:53
Speaker 1: collider and then suddenly you see something you weren't expecting. Yeah, precisely.
4:57
Speaker 1: This is how mu ones were discovered. For example, they
4:59
Speaker 1: had big blocks of photographic materials up on the tops
5:03
Speaker 1: of mountains and they saw these streaks of particles going
5:05
Speaker 1: through them, and the particles weren't consistent with electrons or
5:08
Speaker 1: anything else, and so they said, well, this must be
5:10
Speaker 1: some new particle we haven't seen before. And colliders are
5:14
Speaker 1: actually the best place to discover a new, unexpected particle
5:18
Speaker 1: because you smash the protons together and you get this
5:20
Speaker 1: little blob of energy which can turn into anything. Anything
5:24
Speaker 1: the universe is capable of making, and so you could
5:27
Speaker 1: just pop out some crazy new particle you've never seen
5:30
Speaker 1: before without you knowing that it exists. You don't have
5:33
Speaker 1: to know it's there in order to find it. That's
5:36
Speaker 1: the amazing thing about exploring the universe with colliders. You'd
5:39
Speaker 1: be like, who ordered that exactly where that? That's exactly
5:42
Speaker 1: literally what they said when they heard about the mule,
5:45
Speaker 1: and they said, what, we don't need that. That doesn't
5:47
Speaker 1: make any sense. Go take that somewhere else. Well, we've
5:51
Speaker 1: had several episodes where we talk about the discovery and
5:54
Speaker 1: the search for different particles. We had one about the
5:56
Speaker 1: top cork and the electron and all these other particles.
6:00
Speaker 1: And so today we'll tell the story of another particle,
6:03
Speaker 1: one that was proposed almost forty years ago and that
6:06
Speaker 1: we are still looking for. That's right, this is a
6:09
Speaker 1: particle which may or may not exist, and if it
6:13
Speaker 1: does exist, it may simultaneously solve two of the biggest
6:17
Speaker 1: problems in particle physics and weirdly, it's a particle almost
6:22
Speaker 1: nobody outside the field has even heard of. Wow, well,
6:25
Speaker 1: I guess we we don't know if it exists, and
6:27
Speaker 1: so if it doesn't exist, we have to erase this
6:29
Speaker 1: podcast episode. Daniel or no, we get paid Either way,
6:34
Speaker 1: it doesn't really matter. Okay, forget about that. Well apparently
6:39
Speaker 1: has the one of the citiest names in the history
6:42
Speaker 1: of particles. Yes, I'm looking forward to hearing your reaction
6:45
Speaker 1: to how this particle was named. It ends up with
6:47
Speaker 1: a really pretty cool name. But the reason for that
6:50
Speaker 1: name is really pretty ludicrous and whimsical. Oh man, I
6:54
Speaker 1: am not looking forward to that. But anyway, So today
6:58
Speaker 1: on the podcast, we'll be asking the question, what is
7:04
Speaker 1: the most important particle you've never heard of? It's just
7:08
Speaker 1: like a trendy band that everyone should listen to but
7:11
Speaker 1: nobody knows about. Yeah, this is the particle your teenager
7:14
Speaker 1: knows about, but you are clueless about it. It's super
7:16
Speaker 1: hot on TikTok You're like, what what is TikTok? That's
7:21
Speaker 1: precisely you don't even know the name of the social
7:24
Speaker 1: media app on which this particle is cool. That's how
7:27
Speaker 1: uncool you are. No, but it is. It is a
7:29
Speaker 1: really cool name. I like. I like the sound of
7:32
Speaker 1: the name of this particle. It's this particle is called
7:35
Speaker 1: the axion. That does sound pretty cool. It does sound
7:38
Speaker 1: pretty cool. What doesn't invoke in your mind or him
7:41
Speaker 1: like a robot or you know, like um like access
7:45
Speaker 1: maybe Unfortunately, the word for armpits in Spanish is kind
7:49
Speaker 1: of close to it, So it is making me think
7:51
Speaker 1: a little bit of art pits. But we won't go
7:54
Speaker 1: there is an unfortunate name. It makes me think of
8:00
Speaker 1: sort of like double edged axes being thrown in space
8:03
Speaker 1: along three different axes, you know, like X and y
8:06
Speaker 1: ax and your y ax and your zo throwing an
8:10
Speaker 1: X and X around. I don't know, I don't know,
8:13
Speaker 1: but it is a cool name. It's fun to say.
8:15
Speaker 1: It's got that same sound in their idea. I think
8:19
Speaker 1: as long as it sounds like a transformer, it sounds
8:21
Speaker 1: I think cool. In physics, you know, synchrotron, graviton megatron
8:27
Speaker 1: is not a particle, though the awesome there you go,
8:30
Speaker 1: that will be the name of a particle. Some of
8:32
Speaker 1: you may have heard about the new interesting axon result
8:35
Speaker 1: from the Zenon experiment. Now today we'll be talking about
8:38
Speaker 1: the axon more generally, but we're going to dig into
8:41
Speaker 1: the zenon solar axon question in a dedicated episode coming
8:46
Speaker 1: very soon. But as usual, I was curious, what did
8:49
Speaker 1: people know about the axon? Is this something people actually
8:52
Speaker 1: have heard of or is this something that only the
8:55
Speaker 1: cool kids on physics TikTok know about? And so is
8:58
Speaker 1: Daniel went out there into the files of the Internet
9:00
Speaker 1: to ask people what they know about the axion particle.
9:04
Speaker 1: So thank you to everybody who volunteered to answer random
9:07
Speaker 1: Internet questions and sending in your responses. If you'd like
9:12
Speaker 1: to participate in random person on the street internet questions,
9:16
Speaker 1: then please write to us at questions at Daniel and
9:19
Speaker 1: Jorge dot com. Before you hear these answers, think about
9:22
Speaker 1: it for a second and someone as you if you
9:24
Speaker 1: knew what the axion particle was, what would you say.
9:29
Speaker 1: Here's what people had to say. I think this is
9:31
Speaker 1: a way to classify particles. They like they can be axion,
9:36
Speaker 1: some boat songs and it has to do with them,
9:41
Speaker 1: for example, having mass or not. I don't know. I
9:45
Speaker 1: guess action access would perhaps be some sort of particle
9:50
Speaker 1: that other particles turn around. I have no idea but
9:54
Speaker 1: since it sounds like the word axel, I'm going to
9:56
Speaker 1: guess it has something to do with joining other particles together.
9:59
Speaker 1: I have no idea. I don't know. I think that's
10:03
Speaker 1: to do with what doll matter is might of I
10:07
Speaker 1: believe there are two options, are actions or whimps. Honestly,
10:12
Speaker 1: I have no idea. Because it has the word ion
10:14
Speaker 1: in it, maybe it's some kind of ion. It's got
10:17
Speaker 1: no idea. I never heard about something called axiom. Yeah,
10:22
Speaker 1: of course that's an elementary particle of an action figure
10:26
Speaker 1: the Caveman scientists in your book discussing what the most
10:30
Speaker 1: fundamental particle of a stone ax would be. I assume
10:36
Speaker 1: it's not a standard particle. Maybe it's more like strange matter.
10:43
Speaker 1: All right, not a lot of positive recognition there. I
10:47
Speaker 1: like the one that said it's it's an action figure,
10:49
Speaker 1: or it's related to an action figure, the fundamental element
10:52
Speaker 1: of an action figure. That makes a lot of sense. Well,
10:55
Speaker 1: if it does exist and it is part of nature,
10:57
Speaker 1: it could be part of all action figures. It could be.
11:00
Speaker 1: And the other great idea was the that maybe it's
11:03
Speaker 1: related to axles, so maybe like joins particles together at
11:06
Speaker 1: this some really creative responses here, I'm impressed, or maybe
11:08
Speaker 1: they were thinking like Axel Rose and like oh, I'm
11:11
Speaker 1: a gone some Roses fan, in which case the Axon's
11:14
Speaker 1: career has to also be in the dusk. Yeah, they
11:17
Speaker 1: better get on that physics TikTok right away. Some silly dances.
11:20
Speaker 1: But it did seem like none of these folks had
11:22
Speaker 1: heard of this particle or really had any clue about
11:25
Speaker 1: its incredibly important role in particle physics. Man, well, I
11:28
Speaker 1: would count myself among those numbers. I had no idea
11:32
Speaker 1: what this and have no idea of what this particle
11:35
Speaker 1: is before he sent me the outline for today's episode.
11:38
Speaker 1: But let's get into it, Daniel, what is the axion?
11:41
Speaker 1: It sounds kind of important but maybe not yet discovered. Yeah,
11:45
Speaker 1: the axion particle is totally theoretical, so we do not
11:49
Speaker 1: know if it's part of our universe at all. It
11:51
Speaker 1: may just be an idea in people's minds. And remember
11:54
Speaker 1: there's been a lot more ideas than actual particles. And
11:58
Speaker 1: sometimes these ideas are beautiful, they make perfect sense, and
12:01
Speaker 1: when the physicist has them, they go, Wow, everything is
12:04
Speaker 1: connected and this is the way the universe works. But
12:07
Speaker 1: then you go and you ask the universe like is
12:09
Speaker 1: it real? And Uver says, nice idea, but no, isn't
12:12
Speaker 1: that kind of strange? I feel like that's almost like
12:14
Speaker 1: trying to discover new animals by thinking of them before
12:18
Speaker 1: you actually find. It's like, oh, what if there's an
12:21
Speaker 1: animal with a duck bill, but then at a dinosaur
12:24
Speaker 1: nag and then butterfly wings, and then you go out
12:27
Speaker 1: looking for them. Wouldn't that be kind of not productive? Yeah? Well,
12:30
Speaker 1: but to stretch the you know, mixed metaphor of our
12:32
Speaker 1: rabbit holes here, it's more like that you see evidence
12:35
Speaker 1: for this animal. It's like what's eating all the deer?
12:38
Speaker 1: And you know, I see all these strange footprints, and
12:41
Speaker 1: maybe that would be explained if there was this new
12:43
Speaker 1: predator out there I've never seen before. And so you're
12:46
Speaker 1: trying to like tie up loose ends and complete the
12:49
Speaker 1: picture by suggesting an explanation. And that's exactly what the
12:53
Speaker 1: axion and a lot of other theoretically motivated particles do,
12:56
Speaker 1: is they sort of trying to tie together what we
12:58
Speaker 1: see in a small all are more compact explanation. It's
13:01
Speaker 1: just been a pretty horrible picture of this animal. Daniel
13:04
Speaker 1: because around eating deer. Oh my goodness, it's like a
13:08
Speaker 1: wolf man. You're trying to go for a cool animal wolf,
13:12
Speaker 1: the duck bill and butterfly wings. It does sound pretty cool.
13:15
Speaker 1: That does sound pretty cool. I want to see that
13:16
Speaker 1: animal if it exists, and you can name it. We
13:21
Speaker 1: already use that name for something else. That would be
13:23
Speaker 1: so confusing. But what if you find animal first, right, Like,
13:27
Speaker 1: what if you find animal and call it the axion
13:30
Speaker 1: before you discover this particle. I think we've already used
13:32
Speaker 1: up the name though. That's sort of like, you know
13:34
Speaker 1: how the Space Force television show on Netflix has trademarked
13:38
Speaker 1: the term Space Force before the actual US Space Force
13:42
Speaker 1: got around doing it. Oh that's a problem. That's a problem, yeah, exactly. Anyway,
13:47
Speaker 1: back to particle physics, the axion, if it exists, is
13:51
Speaker 1: a lot like a photon, but it doesn't have zero mass.
13:55
Speaker 1: It has a super tiny, little whispy mask really massive photon. Yeah,
14:01
Speaker 1: but it's not very massive. Like the mass if it
14:03
Speaker 1: has some is like two hundred billion of the mass
14:07
Speaker 1: of the electron, which is already one of the lightest particles.
14:12
Speaker 1: So it's like a light light particle. It's like light light. Exactly.
14:16
Speaker 1: It's very light light light, but not quite light, not
14:19
Speaker 1: quite light. It's not coke zero. It's like coke light, Yeah, exactly,
14:23
Speaker 1: it's that coke with a tiny little bit of real
14:25
Speaker 1: sugar in it, right, Um, And why did somebody come
14:28
Speaker 1: up with this, Well, they came up with it to
14:29
Speaker 1: sort of answer the biggest problem in physics that nobody
14:33
Speaker 1: ever heard of, which is, we're looking at the way
14:35
Speaker 1: that interactions happen in physics, and we noticed something weird,
14:39
Speaker 1: something that we cannot explain. And so it's sort of
14:41
Speaker 1: thought up to explain this other mystery the same way
14:45
Speaker 1: you know, you might hypothesize wolves if you see your
14:48
Speaker 1: dear missing. This is sort of like hypothesizing the axon
14:51
Speaker 1: to explain this other problem, which is called the strong
14:54
Speaker 1: CP problem. Interesting, and now is its official title, the
14:57
Speaker 1: biggest problem with notity has ever heard of? Like, do
15:00
Speaker 1: you guys talk about it that way? Yeah, it's sort
15:03
Speaker 1: of a famous problem that nobody really has any answer
15:05
Speaker 1: to except the axio. And so that's why people think
15:09
Speaker 1: the axon might really be real. And then we'll talk
15:12
Speaker 1: later in the program about how it could also simultaneously
15:15
Speaker 1: solve another huge problem, which makes the axon sort of
15:18
Speaker 1: a sexy particle right now. But it was originally dreamt
15:22
Speaker 1: up to solve this other problem called the strong CP problem.
15:25
Speaker 1: So what what's the strong CP problem? So this problem
15:28
Speaker 1: has to do with basically, why does the strong force
15:31
Speaker 1: not break some symmetries and particle physics, we have all
15:34
Speaker 1: these symmetries like charge symmetry and parity symmetry and time symmetry.
15:39
Speaker 1: These symmetries tell us whether something works the same when
15:43
Speaker 1: you flip it the other way. Like, if we say
15:46
Speaker 1: something could happen to an electron, we ask, well, can
15:48
Speaker 1: the same thing happen to a positron, which is the
15:51
Speaker 1: opposite charge version of it. Because we like symmetries in
15:55
Speaker 1: particle physics, we like the smallest set of rules, so
15:57
Speaker 1: we don't want a different set of rules for electron
16:00
Speaker 1: ones and for positrons for example. So it's kind of like,
16:02
Speaker 1: you know, like if two negative electrons propel each other,
16:06
Speaker 1: you can ask, like to positive electrons propel each other too,
16:09
Speaker 1: and if they do, then that means it's like symmetric.
16:11
Speaker 1: That's right, it's symmetric in charge. If you flip the
16:14
Speaker 1: charge and you get the same thing, and then it's
16:16
Speaker 1: symmetric in charge, and so we call that C for
16:19
Speaker 1: charge symmetry, and we ask that question about everything, and
16:22
Speaker 1: electromagnetism is charge symmetric. Everything that happens in electromagnetism would
16:28
Speaker 1: happen the same way if you flipped all of the charges,
16:30
Speaker 1: not just one, but all of the charges, okay. And
16:33
Speaker 1: then the second one is called P for parity violation,
16:37
Speaker 1: and that says, would the same thing happen if you
16:39
Speaker 1: did it in the mirror. So, if you like set
16:42
Speaker 1: up some particle experiment or particle decays to two other ones,
16:46
Speaker 1: or two particles collide into each other or whatever, and
16:49
Speaker 1: then you put that experiment in front of a mirror,
16:52
Speaker 1: the thing that happens in the mirror is not exactly
16:54
Speaker 1: the same as the thing that's happening in real life.
16:56
Speaker 1: It's flipped in one dimension. Yeah, a mirror will flip
17:00
Speaker 1: like the Z axis, for example, the axis perpendicular to
17:03
Speaker 1: the mirror, but not the other two. So, for example,
17:06
Speaker 1: if you hold up your left hand in front of
17:08
Speaker 1: a mirror, then it looks like your right hand doesn't
17:10
Speaker 1: look like your left hand, and so your hand has parody.
17:14
Speaker 1: It's not parody symmetric, right, because it doesn't look the
17:17
Speaker 1: same in the mirror. Doesn't look the same, but like
17:19
Speaker 1: a like a ball does sort of look like a
17:21
Speaker 1: perfectly round ball with no drawings or features on it
17:25
Speaker 1: does is parody symmetric because it looks the same in
17:28
Speaker 1: the mirror exactly. So for a long time, this is
17:30
Speaker 1: this thought that all of particle physics was charged symmetric
17:34
Speaker 1: and parody symmetric because it just sort of made sense, right,
17:38
Speaker 1: and this is like to do that. They say, the
17:40
Speaker 1: universe is beautiful and natural, and so it should follow
17:43
Speaker 1: this rule, Like it'd be weird if the electron looked
17:45
Speaker 1: like my right hand in front of the mirror, or
17:47
Speaker 1: if you had electrons for hands, that would also be weird,
17:50
Speaker 1: but for different reasons. And for a long time, everybody
17:52
Speaker 1: assumed that everything followed all these rules. And then in
17:56
Speaker 1: the fifties people realized, oh, nobody had ever actually checked this.
17:59
Speaker 1: For the weak force, we had a whole episode we
18:02
Speaker 1: dug into how the weak force actually violates parity. Interesting, Yeah,
18:06
Speaker 1: if you have a reaction in the mirror, it looks
18:08
Speaker 1: different than the reaction you're having like in your actual laboratory.
18:12
Speaker 1: And when we're talking about these These are particles, right,
18:14
Speaker 1: so they don't have features like hands, but they'll do
18:17
Speaker 1: things like they'll turn a certain way in a magnetic field,
18:20
Speaker 1: or they'll they'll react a certain way when they hit
18:23
Speaker 1: something else. Right. Yeah, the experiment that discovers the violation
18:25
Speaker 1: of parody did just that. It like takes a bunch
18:28
Speaker 1: of nuclei, aligns them in a magnetic field, and then
18:31
Speaker 1: watches the direction that they emit electrons. Is it like
18:34
Speaker 1: in the same direction as the magnetic field or backwards?
18:37
Speaker 1: And that's a fascinating experiment that if you're interested in
18:40
Speaker 1: you should dig into that whole podcast episode. But for
18:43
Speaker 1: a whild people thought, okay, parody is violated by the
18:45
Speaker 1: weak force. What about the combination of charge and parody?
18:50
Speaker 1: So put it in the mirror and flip the charge,
18:53
Speaker 1: so that says, will an electron look the same if
18:56
Speaker 1: you put it in the mirror and turn it into
18:58
Speaker 1: a positron? And then we discovered that that the weak
19:02
Speaker 1: force actually violates this also, so we call this c P.
19:06
Speaker 1: If an interaction or a particle physics thing that happens
19:10
Speaker 1: violates CP, it means that it doesn't look the same
19:13
Speaker 1: when you flip the charge and put it in the mirror.
19:15
Speaker 1: So and so the weak force violates parody, and it
19:20
Speaker 1: also violates charge and parody. That's right now violates parody
19:24
Speaker 1: big time. It's like a really big violation. And that
19:27
Speaker 1: was a Nobel prize. And then people thought, well, it
19:30
Speaker 1: must then preserve CP. It must be that parody is violated,
19:33
Speaker 1: but the combination of these two things is still preserved.
19:36
Speaker 1: And then they discovered that they violates CP, and that
19:39
Speaker 1: was another Nobel prize. So that's the weak force. A
19:43
Speaker 1: weak force violates CP, and that was sort of surprising.
19:46
Speaker 1: But then people realized, well why not, I mean, why
19:49
Speaker 1: shouldn't these things violate CP. They looked at the way
19:52
Speaker 1: that we write down these interactions and the way we
19:54
Speaker 1: understand these theories, and we say, well, it's actually totally
19:57
Speaker 1: natural for them to violate CP. So like the theorist
20:00
Speaker 1: went from that's impossible, that's absurd, to actually make a
20:03
Speaker 1: perfect sense. All right, Well, it sounds like there's a
20:06
Speaker 1: lot going on with the weak force here. It violates
20:08
Speaker 1: all kinds of symmetries, and so let's talk about some
20:11
Speaker 1: of the other forces and how that could maybe lead
20:13
Speaker 1: people to come up with a brand new particle called
20:16
Speaker 1: the axion. But first let's take a quick break. All right, Diane,
20:32
Speaker 1: we're we're talking about a potentially existing particle with a
20:36
Speaker 1: cool name called the axion, and you're telling me that
20:39
Speaker 1: it's definitely related to this idea of the CP problem,
20:43
Speaker 1: which is like a problem in theoretical physics about the
20:46
Speaker 1: symmetry of particles and whether or not they act the
20:50
Speaker 1: same way in all kinds of situations. And so we
20:53
Speaker 1: talked about how the weak force doesn't follows parody or
20:57
Speaker 1: charged parody symmetry, and so and and that's now become
21:01
Speaker 1: the normal. Before we gave them people a norval price.
21:03
Speaker 1: We're figuring that out. But now it's like, okay, that's
21:06
Speaker 1: the way, that's right. We realize that it's actually not
21:09
Speaker 1: outrageous for the weak force to violate CP. And then
21:12
Speaker 1: we looked at the other forces. We said, you know,
21:14
Speaker 1: the same thing that allows the weak force to violate CP,
21:18
Speaker 1: why doesn't it also allow the strong force to do it? Like,
21:21
Speaker 1: the strong force could also violate CP, No big deal,
21:25
Speaker 1: as the sort of same freedom inside it. It also
21:28
Speaker 1: interacts with corks, which is what the weak force does
21:31
Speaker 1: when it violates parody, and so people thought, oh, well,
21:33
Speaker 1: the strong force, maybe that also violates CP. But but
21:37
Speaker 1: it doesn't. But it doesn't. And we've made really really
21:41
Speaker 1: precise measurements of this, like crazy precise measurements, and so
21:45
Speaker 1: the strong force observes CP sort of for no good reasons. Interesting, so, like,
21:52
Speaker 1: if you try the strong force, it seems to be symmetric.
21:56
Speaker 1: It follows the rules. It's like, it follows the rules.
21:59
Speaker 1: It's the good citizen of physics. Yeah, it's like if
22:02
Speaker 1: you were watching people drive down the highway and every
22:04
Speaker 1: single one of them was driving exactly at the speed limit,
22:07
Speaker 1: no higher, no lower, to like one billions of a
22:10
Speaker 1: mile per hour, you'd be like, that's weird. That would
22:12
Speaker 1: be suspicious precisely, and you'd wonder, like, oh, maybe there's
22:16
Speaker 1: a speed trap out there or something like that. Ord
22:19
Speaker 1: their engines are fixed or something. You look for a reason, right,
22:22
Speaker 1: or they're all using cruise control. Yeah, precisely, and it's
22:26
Speaker 1: automated by the government or something. And so that's what
22:29
Speaker 1: makes us wonder. We see this parameter in the strong
22:32
Speaker 1: force that would very naturally allow for the strong force
22:35
Speaker 1: to violate CP, but it doesn't. It's like this angle
22:38
Speaker 1: that would allow it is set to exactly zero, and
22:41
Speaker 1: that seems weird. It seems like it needs an explanation.
22:44
Speaker 1: And that's the strong CP problem is why doesn't the
22:47
Speaker 1: strong force violate CP. It's called I just got it, Daniel.
22:51
Speaker 1: It's called the strong CP problem because it applies to
22:53
Speaker 1: the strong force, that's right, not because it's a strong problem. Well,
22:59
Speaker 1: you know something, problems are called like the you know,
23:01
Speaker 1: like in uh, I don't know, the hard problem of consciousness, etcetera. Yeah,
23:05
Speaker 1: or in computer science and they're like, you know, strong
23:08
Speaker 1: there is the strong and thropic principle and the weakend
23:10
Speaker 1: thropic principle. Yeah there you go. Yeah, I'm not crazy
23:14
Speaker 1: that those exist. But that doesn't mean you're not crazy, Okay, Right,
23:17
Speaker 1: it's not an exclusionary all right. So, um, it's the
23:20
Speaker 1: strong city people, But it's not actually a problem. It's
23:22
Speaker 1: more like it's like a strong why does it follow
23:25
Speaker 1: the rules? Yeah? Question, it's not really a problem, right,
23:28
Speaker 1: Like it's not causing any problem. It's just something that's
23:31
Speaker 1: it's hard to understand why it doesn't break the rules. Yeah,
23:35
Speaker 1: it's not gonna like fundamentally rip the universe. Apart or something.
23:37
Speaker 1: It's not gonna bring the apocalypse upon us or anything.
23:40
Speaker 1: We don't have to call Bruce Willis. It's not that
23:42
Speaker 1: kind of problem. It's the why does this work that
23:45
Speaker 1: way when it doesn't have to? You know, it's it's strange.
23:50
Speaker 1: And anytime you see something unexplained and weird, a pattern
23:52
Speaker 1: you don't understand in physics, you've got to ask why,
23:55
Speaker 1: and you've got to think, is there a simpler explanation?
23:57
Speaker 1: Is there something that's making this happen? So some people,
24:00
Speaker 1: I guess I had to think of this question, right
24:03
Speaker 1: because before you thought that was totally normal. It was
24:06
Speaker 1: following the rules, but now it's weird. Suddenly became weird
24:09
Speaker 1: that it was following the rule. Yeah, exactly. Once we
24:12
Speaker 1: realized the rules could be broken, we thought, hey, how
24:14
Speaker 1: come everybody's gonna breaking the rules? Right? Why is the
24:17
Speaker 1: strong force over there being so nice but you can
24:19
Speaker 1: drive as fast as you want in the highway? Why
24:22
Speaker 1: is everyone driving under the speed limit? Yeah? The weak
24:24
Speaker 1: forces like driving the wrong way, it's driving any speed,
24:26
Speaker 1: it's driving the mill of the night, it's like going
24:28
Speaker 1: off road. And the strong forces like driving Miss Daisy
24:31
Speaker 1: right down in the right in the correct lane. Oh man,
24:36
Speaker 1: all right, so um, so that's weird. And so people
24:38
Speaker 1: started asking this question in the seventies. Yeah, it was
24:41
Speaker 1: in the seventies that people came up with maybe the
24:44
Speaker 1: first answer to this question. People started asking this question
24:47
Speaker 1: basically after CP violation was discovered, which is, you know,
24:51
Speaker 1: just a few years earlier. And then people came up
24:53
Speaker 1: with his explanation, and it's from Roberto Pechy and Helen Quinn.
24:57
Speaker 1: There's the nineteen seventy seven and of course very three
25:00
Speaker 1: is let's think up a new quantum field that fills
25:03
Speaker 1: the whole universe. Like that's the go to course. Let's
25:09
Speaker 1: just add more things to the zoo, I know. And
25:12
Speaker 1: it feels complicated, right, it feels counterintuitive, like we're trying
25:15
Speaker 1: to simplify things, and to simplify things, we have to
25:18
Speaker 1: add a new complicated bit. Like yeah, that's all right,
25:21
Speaker 1: It's that seems counterintuitive. But it's like say you're trying
25:24
Speaker 1: to describe how an engine worked and you were missing
25:26
Speaker 1: the pistons. You'd be like, well, this doesn't really make sense.
25:29
Speaker 1: I'm gonna add one more piece. Oh look, it all
25:31
Speaker 1: clicks together now it makes sense and so sometimes you
25:34
Speaker 1: have to add one missing piece in order to make
25:37
Speaker 1: the whole machine work, or your understanding of the machine
25:39
Speaker 1: work at least. Right. Well, I imagine it's weird because
25:43
Speaker 1: you know, really, you guys, I sort of just looking
25:45
Speaker 1: at some equations on a page, right, But it's like, oh,
25:48
Speaker 1: if I, if I could add just one number here
25:50
Speaker 1: would work. But really you're like you're adding a whole
25:53
Speaker 1: new field to the entire universe just by putting that number.
25:57
Speaker 1: Some of us experimentalists do more than just look at
26:00
Speaker 1: pencils and paper, you know, we actually go out and
26:02
Speaker 1: smash particles and try to make this stuff. Oh sorry, yeah,
26:04
Speaker 1: you also look at computer screens. That's right. That is
26:07
Speaker 1: fundamentally different. Okay. My wife used always tease me that
26:11
Speaker 1: my research was just quote on the computer and therefore
26:14
Speaker 1: wasn't real research. I see, you don't make chemicals, or
26:18
Speaker 1: you don't have to wear a lab code. I'm not
26:20
Speaker 1: wearing a lab coade, So how can it be science? Right, exam,
26:24
Speaker 1: you can, but it's just strictly cosmetic, that's right. And
26:26
Speaker 1: so they thought of this field, and they said, well,
26:28
Speaker 1: what if there's this new field that fills up all
26:31
Speaker 1: of space, and it's connected to the same field that
26:35
Speaker 1: controls the strong force, this field of quantum chromodynamics, the
26:39
Speaker 1: field of the gluons, these particles that mediate the strong force,
26:43
Speaker 1: and what if it talks to those, It like interacts
26:45
Speaker 1: with those, and it basically keeps it in line. And
26:48
Speaker 1: so there's this new field created in a very early
26:51
Speaker 1: universe with everything else, and it sort of pushes the
26:54
Speaker 1: strong force in the direction of having no CP violation
26:58
Speaker 1: I see, but not the other forces like it only
27:01
Speaker 1: somehow affects the strong force. That's right, only affects a
27:04
Speaker 1: strong force. And it was created just with everything else.
27:08
Speaker 1: And then in the first sort of a few moments
27:10
Speaker 1: of the universe, it pushed the strong force towards having
27:14
Speaker 1: a zero value for this angle that controls the CP violation.
27:18
Speaker 1: So not instantaneously like there may be in like a
27:21
Speaker 1: bill of second there in the very early universe where
27:24
Speaker 1: the strong force could violate CP. But then it was
27:27
Speaker 1: sort of like pushed in line by this other field. Really,
27:30
Speaker 1: but I guess my question is why do you need
27:32
Speaker 1: this special field? Couldn't did just say that the strong
27:35
Speaker 1: force that's the way it is, like it was born
27:38
Speaker 1: with this angle. Why do you need to bring in
27:40
Speaker 1: like a field that accent it and then somehow disappears. Yeah,
27:43
Speaker 1: you could go with the non answer right to say,
27:45
Speaker 1: you know, physics doesn't have explanations, so stop asking questions.
27:49
Speaker 1: You know, like the numbers just are what they are.
27:52
Speaker 1: It's not really satisfying. You wonder like why is it
27:55
Speaker 1: this and not that? Especially when the numbers are a
27:57
Speaker 1: simple value. I mean, if the number is like point
27:59
Speaker 1: four to one seven, you wonder what it is. But
28:01
Speaker 1: when the number is like zero or one's just it
28:05
Speaker 1: hints at something else happening. It hints at something else
28:08
Speaker 1: controlling it. Just like seeing those people drive down the
28:10
Speaker 1: street at all the same speed. You wonder what's doing it?
28:13
Speaker 1: But I guess you know, like how does it adding
28:15
Speaker 1: a whole new field help Because we had a whole
28:17
Speaker 1: new field. Then you have to ask why does that
28:18
Speaker 1: field exist? Yeah, exactly, just like you have to ask
28:21
Speaker 1: why do the pistons exist in the engine. But if
28:23
Speaker 1: you think them up, it does simplify all the parts
28:26
Speaker 1: working together in the way that you observe. And so
28:30
Speaker 1: they thought of this field and they try to make
28:31
Speaker 1: it as simple as possible and very naturally connected to
28:35
Speaker 1: the strong force, and in in that connection between the
28:38
Speaker 1: strong force and this new field forced the strong force
28:41
Speaker 1: sort of automatically to have zero CP violation. It's sort
28:45
Speaker 1: of like transforming one question into another. You're saying, you know,
28:49
Speaker 1: why is this angle? Zero gets transformed into why does
28:52
Speaker 1: this field exist? Sure? Okay, and that's I guess that's
28:55
Speaker 1: a more comfortable question for you, guys, because because we
28:58
Speaker 1: like fields, man, because then without it you get out
29:02
Speaker 1: of a job. Well, also, the field is something we
29:06
Speaker 1: could discover, right, and so if this field exists, we
29:10
Speaker 1: can go out and find it, and then you can ask, Okay,
29:12
Speaker 1: why does that field exists? Why do we need all
29:13
Speaker 1: these fields? Is it part of some larger strategy. I
29:16
Speaker 1: don't know, but it is something that we can test
29:19
Speaker 1: and fine, right, as opposed to like just some weird
29:21
Speaker 1: property of the strong force. Yeah, you can measure this
29:24
Speaker 1: property the strong force all day long and say zero.
29:27
Speaker 1: That doesn't help you understand why it happens. If it,
29:29
Speaker 1: if it can transform into it's forced to happen because
29:32
Speaker 1: this field exists, and we can prove that field exists,
29:35
Speaker 1: then we can start to think about the larger puzzle
29:37
Speaker 1: and like, well, why this field and does this mean
29:39
Speaker 1: other fields have to exist? And what does this tell
29:41
Speaker 1: us about the pattern of all the fields, which is
29:43
Speaker 1: sort of the larger mission of particle physics is to
29:46
Speaker 1: understand how all the fields fit together into one. Right.
29:48
Speaker 1: And I guess it's not totally crazy because that's how
29:51
Speaker 1: they discovered the Higgs boson, right, Like you thought of
29:53
Speaker 1: a field to patch something in your theories, and then
29:57
Speaker 1: you found the particle that belonged to that field. So
30:00
Speaker 1: it's all sort of been buttoned up. Yeah, exactly. The
30:02
Speaker 1: question there was like, why does the photon have no
30:05
Speaker 1: masks and these other particles do have masks? Can you
30:07
Speaker 1: explain that? And some people were like, hey, just accept
30:10
Speaker 1: it and move on, man, but Higgs was like, no,
30:13
Speaker 1: I'm going to create a new field that explains it.
30:15
Speaker 1: And he was right. And so now we can of
30:17
Speaker 1: course ask a questions like why is there a Higgs
30:19
Speaker 1: field dot dot We get to get onto the next question.
30:22
Speaker 1: And so just like that, this new field creates a
30:26
Speaker 1: new particle, and that new particle is something we could discover,
30:30
Speaker 1: all right. And so there's a fun story and by
30:33
Speaker 1: fun I mean crazy story about how it was name,
30:36
Speaker 1: how they name axion came about, so tells the story.
30:39
Speaker 1: So it's it's sort of funny for two reasons. First
30:41
Speaker 1: of all, Petchi and Quinn, who thought of this field,
30:44
Speaker 1: forgot to name the particle. Like they came up with
30:46
Speaker 1: this field, and of course, naturally the field exists, that
30:50
Speaker 1: it's possible for the field to get like an excited
30:52
Speaker 1: bundle of energy, which we call a particle. But they
30:55
Speaker 1: didn't name the particle. And so another physicist came along,
30:59
Speaker 1: Frank will Check, who's famous and he won a Nobel
31:02
Speaker 1: Prize for understanding how quirks interact with each other with
31:05
Speaker 1: a strong force. He decided to name it. He's like, well,
31:08
Speaker 1: let's think about this field and how we might see it.
31:11
Speaker 1: And of course he thought about the particle, and then
31:13
Speaker 1: he had to give it a name. No how he
31:15
Speaker 1: got to name it, but the particle already had parents.
31:17
Speaker 1: How can you just go in and like name somebody
31:19
Speaker 1: else's kids. Say you met a family and they didn't
31:22
Speaker 1: give their kids a name, you would probably come up
31:24
Speaker 1: with a nickname for it, right, You wouldn't want to
31:26
Speaker 1: say that kid's name. I would tell the parents to
31:29
Speaker 1: give him a name. I would ask the parents, what
31:31
Speaker 1: do they call what do they say when they want
31:33
Speaker 1: the kid to come over? Well, then you are more
31:35
Speaker 1: modest than Frank will Check, which is true for almost
31:38
Speaker 1: all of humanity anyway. Oh my goodness. So wait they
31:41
Speaker 1: but did they name? Did Peshi and Helen Quinn name
31:44
Speaker 1: the field at least? Or did they just say like
31:47
Speaker 1: a field? Yeah, a field? They just gave it a
31:49
Speaker 1: mathematical symbol, right. They didn't give a name to the
31:51
Speaker 1: particle that comes from it. And so you know, if
31:54
Speaker 1: Frank Wilcheck had been less modest, he would have called
31:56
Speaker 1: it the Petchy Quinn particle or something, or the field
31:59
Speaker 1: or what will Check called the field? Yeah, well now
32:01
Speaker 1: it's called the Axion field. Oh man, he totally took
32:05
Speaker 1: it over. He totally took it over. And on top
32:08
Speaker 1: of that, he gave it a totally ridiculous name, like
32:11
Speaker 1: Axon is a cool name. But he got the idea
32:13
Speaker 1: when he was grocery shop. Oh no, what happened. He
32:16
Speaker 1: was in the aisle for laundry detergent and he saw
32:19
Speaker 1: this laundry detergent called Axion detergent booster, and he thought Axion,
32:24
Speaker 1: that's kind of a cool name. Oh no, well, he
32:28
Speaker 1: was what was he thinking, like this particle that I'm
32:31
Speaker 1: earth surfing and stealing from this other other physicists would
32:35
Speaker 1: clean everything up pretty well. So, hey, laundry detergent makes
32:38
Speaker 1: perfect sense. It's a physics booster, so we need a
32:40
Speaker 1: detergent booster. Yeah, so somebody in some marketing department created
32:45
Speaker 1: the name for this laundry detergent, which ended up naming
32:48
Speaker 1: a theoretical particle. But didn't they copyrighted? Can you do that?
32:53
Speaker 1: That's a great question. Can you name a particle after
32:55
Speaker 1: like U copyrighting your name in a particle like the
32:58
Speaker 1: Nintendo Switch particle or like the Netflix particle. Can't do that?
33:04
Speaker 1: You know, that's a question for our legal department, for
33:06
Speaker 1: the physics lawyers. You stumped me on that one. Through
33:09
Speaker 1: the physics lawyers, of whom I am not one. And
33:11
Speaker 1: you know, there was competition. There were other famous Nobel
33:14
Speaker 1: Prize winning physicists like Stephen Weinberg. He wanted to call
33:18
Speaker 1: it the Higgs lit because he thought, oh, this is
33:21
Speaker 1: only reminds me a little bit of the Higgs boson,
33:23
Speaker 1: So he wanted to call it things you're gonna say.
33:24
Speaker 1: You wanted to name it clox or Kleenex or the
33:30
Speaker 1: tidy no particle um no and accalon sort of stuck.
33:34
Speaker 1: And you know, these things are not fair, and they're
33:36
Speaker 1: not always done the right way. Like we talked about
33:39
Speaker 1: how quirks are named quarks because the famous physicists came
33:42
Speaker 1: up with the name, even though a young physicist came
33:45
Speaker 1: up with the name aces before that and it was
33:47
Speaker 1: sort of buried in obscurity. But these things are not
33:50
Speaker 1: always done correctly. They're not always given to the people
33:52
Speaker 1: who to That's right, Yeah, it's not always fair. It's
33:56
Speaker 1: just sort of like what people end up calling something.
33:59
Speaker 1: All right, Well let's get into why this action is
34:03
Speaker 1: super duper cool and why we think it could be real.
34:08
Speaker 1: But first let's take a quick break. All right, Daniel,
34:22
Speaker 1: we're talking about the Axon and it got its name
34:25
Speaker 1: from a laundry detergent, which is I guess not too
34:28
Speaker 1: surprising in physics, because you know, I'm not impressed by
34:32
Speaker 1: the general imagination and naming things. But it is a
34:36
Speaker 1: cool sounding name at least, you know, it satisfies your
34:38
Speaker 1: transformer principle. Well well, why then did you still Megatron's name,
34:42
Speaker 1: you know, Optimus Prime? Yeah, maybe they had better lawyers. Right,
34:46
Speaker 1: the detergent companies lawyers are not as good as the
34:48
Speaker 1: transformers has bro. Yeah, that is a little bit scarier. Alright.
34:53
Speaker 1: So you're telling me that this particle is cool because
34:56
Speaker 1: it would answer the question of why the strong force
34:59
Speaker 1: the is not violate some of these symmetry conditions in
35:03
Speaker 1: the universe and that. But it could also be cool
35:06
Speaker 1: because it explained another big problem. Yeah, there's another big
35:09
Speaker 1: problem in particle physics, which is where is all the stuff? Right,
35:14
Speaker 1: we know that most of the stuff in the universe
35:17
Speaker 1: is not made of quarks and electrons or any other
35:20
Speaker 1: kind of familiar matter. It's a man of this new
35:22
Speaker 1: thing that we call dark matter, even though we don't
35:25
Speaker 1: really know what it is. And just like with the
35:28
Speaker 1: other sort of physics mysteries, we see evidence for it
35:31
Speaker 1: and how galaxy spin and how light bends through space,
35:35
Speaker 1: but we don't know what it is and what it's
35:37
Speaker 1: made out of. So it's one of the biggest pressing
35:39
Speaker 1: questions in particle physics, or I think in modern science,
35:43
Speaker 1: what is the matter of the unit? What is dark matter? Right?
35:46
Speaker 1: And so it could be axios, it could be laundry detergent,
35:50
Speaker 1: it could be exactly the dark matter could be scrubbing
35:53
Speaker 1: the universe. It seems ironic that dark matter would be
35:57
Speaker 1: something that's supposed to get the stains out reisely. Well,
36:01
Speaker 1: it satisfies a lot of the requirements you need for
36:03
Speaker 1: a dark matter doesn't interact with normal matter, so we
36:06
Speaker 1: wouldn't have seen it. That's what makes it dark. It
36:08
Speaker 1: has some mass to it, although it's very very light.
36:12
Speaker 1: So if it were dark matter, you would need like
36:14
Speaker 1: a ridiculous number of these things. You need like two
36:18
Speaker 1: hundred billion just to make the mass of one electron,
36:22
Speaker 1: and we need enough to make five times as much
36:25
Speaker 1: mass as everything in the universe. And so like, if
36:28
Speaker 1: axions are the dark matter and they are real, then
36:31
Speaker 1: we are swimming and swimming and jillions of axions all
36:36
Speaker 1: the time, meaning that um, if these particles exist and
36:41
Speaker 1: they explained this strong force problem, they could also be there,
36:45
Speaker 1: but we wouldn't see them. Like they don't interact with
36:47
Speaker 1: the electromagnetism. That's right, they don't interact with electromagnetism, and
36:51
Speaker 1: they do connect to the strong force, but only in
36:54
Speaker 1: this way that they make the strong force not violate CP.
36:59
Speaker 1: The field also has some other super duper heavy particles
37:02
Speaker 1: in it that do interact with a strong force, but
37:05
Speaker 1: they're so heavy that they potentially don't exist, and so
37:08
Speaker 1: we don't have to worry about them. And so effectively,
37:10
Speaker 1: axions are totally inert except for the fact that they
37:14
Speaker 1: have a small mass. And so if they have this mass,
37:17
Speaker 1: then they contribute to gravity. And that's what dark matter is.
37:20
Speaker 1: It's something mysterious out there that's adding gravity to the universe,
37:24
Speaker 1: and so it could be the act All right, well,
37:26
Speaker 1: would that be sort of a coincidence that we have
37:29
Speaker 1: this particle and it just so happens to fill in
37:31
Speaker 1: the blankford dark matter? It would be amazing, Like who
37:34
Speaker 1: wouldn't want to solve two big problems in physics at once, Right,
37:38
Speaker 1: you think of this particle to solve one problem, and boom,
37:41
Speaker 1: it turns out to solve the other problem at the
37:43
Speaker 1: same time. You can collect two Nobel Prizes in one trip.
37:47
Speaker 1: I mean that sounds pretty. You get to like, do
37:48
Speaker 1: you get too in the same ceremony? I wonder I
37:51
Speaker 1: think you have to come back the next year. I'm
37:53
Speaker 1: not sure, but that's attractive but also makes you a
37:56
Speaker 1: little suspicious, Like we thought this particle up to explain
37:59
Speaker 1: the strong ep problem, and then we have this other problem.
38:01
Speaker 1: We're gonna try to sort of squeeze this particle into
38:04
Speaker 1: solving the dark matter problem. It actually sort of reflects
38:08
Speaker 1: something else about the dark matter problem, which is that
38:10
Speaker 1: we're getting a teensy bit desperate. Like we thought we
38:14
Speaker 1: would have figured out dark matter by now. We had
38:16
Speaker 1: better ideas for what dark matter could be, these weakly
38:19
Speaker 1: interacting massive particles stuff like that, and none of that
38:22
Speaker 1: has really panned out, and so now we're sort of
38:25
Speaker 1: like dragging along the bottom of the barrel looking for
38:27
Speaker 1: other ideas that might explain dark matter. And so that
38:31
Speaker 1: sort of led to a resurgence and interest in the axons.
38:34
Speaker 1: People think, wait a second, what about axons? Maybe those
38:38
Speaker 1: could be the dark matter. Like so desperate, you're reaching
38:40
Speaker 1: for the non brand laud exactly what you're saying, that's
38:45
Speaker 1: exactly where we are. And it could also maybe solve
38:47
Speaker 1: another big problem, right it could it could solve another
38:49
Speaker 1: big problem. That was a really fascinating paper out there
38:52
Speaker 1: last year that talked about those first few moments in
38:55
Speaker 1: the universe when this field was created and it forced
38:58
Speaker 1: the strong field to not violate CP and it turns
39:01
Speaker 1: out when it did that, it had sort of two directions.
39:04
Speaker 1: It could go sort of like imagine a marble in
39:07
Speaker 1: an upside down hat, and it's rolling towards the bottom,
39:10
Speaker 1: and that's how it forces the strong force to not
39:13
Speaker 1: violate CP. But if instead of just rolling strength down,
39:16
Speaker 1: what if it had like a little bit of a kick,
39:18
Speaker 1: so it sort of went around in a circle and
39:20
Speaker 1: then relaxed to the center, then it could have done
39:23
Speaker 1: it clockwise or counterclockwise. Oh boy, it's like another symmetry.
39:27
Speaker 1: It's another symmetry. And it turns out if it goes clockwise,
39:30
Speaker 1: then the universe is filled with matter, and if it
39:33
Speaker 1: goes counterclockwise, the universe is filled with anti matter. What
39:38
Speaker 1: it's like flipping a coin. We could have been made
39:40
Speaker 1: out of antimatter. Yes, And that's a big question in physics,
39:43
Speaker 1: is like why is the universe made out of matter
39:46
Speaker 1: and not antimatter? And we don't know. And it feels
39:48
Speaker 1: like a coin was flipped and it could be that
39:51
Speaker 1: this was the coin. It was a laundry detergent coin
39:55
Speaker 1: that determined the entire universe. Yeah, and so the axon
40:00
Speaker 1: could solve this other problem also, so it really could
40:04
Speaker 1: be key to a lot of these big, big mysteries
40:07
Speaker 1: in particle physics. And I guess you're because I imagine
40:09
Speaker 1: you were saying that this is not the only idea,
40:12
Speaker 1: like this is not the only field or particle that
40:16
Speaker 1: people have dreamed of, but this one is somehow more
40:19
Speaker 1: attractive because it's sort of makes more sense, well, because
40:22
Speaker 1: the other ones have been sort of ruled out. You know,
40:24
Speaker 1: you have your first idea, you go look for it,
40:26
Speaker 1: the experiment says no, sorry. Then you go for your
40:29
Speaker 1: second idea, you know, and you just keep looking through
40:31
Speaker 1: ideas until you find one that the universe says yes to.
40:35
Speaker 1: And so that's sort of led to a resurgence. And
40:37
Speaker 1: you know, also theoretical physics, there are trends, there are fads.
40:41
Speaker 1: People get excited about an idea and they work on
40:43
Speaker 1: it furiously, and then they get bored with it. Somebody
40:45
Speaker 1: else comes up with a new idea, and so the
40:47
Speaker 1: idea sort of have cycles. You know, People get bored
40:50
Speaker 1: of an idea, put it aside, and then twenty years later,
40:53
Speaker 1: some new young woman says, hey, I have found a
40:56
Speaker 1: new way to use this old idea, and then everybody
40:58
Speaker 1: gets excited about it. Again, it's a human endeavor, all right.
41:01
Speaker 1: So then the action is is trending is what you're saying,
41:04
Speaker 1: Like it's it's having a popularity, surgeon popularity. And so
41:09
Speaker 1: I guess the question is is it real? Like does
41:11
Speaker 1: it actually exist? And can I find it in places
41:14
Speaker 1: not my laundry the diurgent aisle at my grocery store. Well,
41:18
Speaker 1: we don't know, but there are experiments out there to
41:20
Speaker 1: look for it, sort of two different categories of experiments
41:23
Speaker 1: that both use magnetic fields. The idea is that the
41:27
Speaker 1: axion is still or like a photon and it doesn't
41:31
Speaker 1: interact with photons and normally, but it turns out that
41:33
Speaker 1: if you put the axion into a super duper strong
41:37
Speaker 1: magnetic field, then sometimes it will turn into photons. Wait,
41:42
Speaker 1: a magnetic magnetic field can cause particles to change. Yes,
41:46
Speaker 1: the magnetic field will change the way the particles interact. Right,
41:49
Speaker 1: it has energy in it, and if those particles can
41:52
Speaker 1: feel photons in any sort of way, then they can
41:55
Speaker 1: get enhanced and they can change the way they decay.
41:58
Speaker 1: And so the axion and if it's in a chamber
42:01
Speaker 1: that sort of resonates with it and it's that chamber
42:04
Speaker 1: is filled with magnetic field, and this magnetic fields is
42:07
Speaker 1: like a hundred and fifty thousand times the strength of
42:10
Speaker 1: the Earth's magnetic field, then it could sometimes turn into
42:14
Speaker 1: like little microwave photons. So they have this cavity up
42:17
Speaker 1: in University of Washington where they have very cold and
42:21
Speaker 1: they have a very powerful magnetic field, and they're just
42:24
Speaker 1: listening for a little microwave blip, so that we can't
42:27
Speaker 1: see them, but they might turn into things. We can
42:30
Speaker 1: see them precisely into in need these weird conditions, in
42:33
Speaker 1: very strange, very strong conditions, they might turn into photons. Really,
42:37
Speaker 1: you can predict that with the equations. The equations say
42:40
Speaker 1: should happen if you get the magnetic field at the
42:43
Speaker 1: right frequency and you get it down to cold enough conditions,
42:47
Speaker 1: and they've been running it for a while and they
42:49
Speaker 1: haven't seen them, but they're sort of like tuning the
42:50
Speaker 1: magnetic field, like are they over here? Are they over there?
42:53
Speaker 1: And so far they haven't seen anything, but it's sort
42:56
Speaker 1: of getting more and more powerful. The device pretty cool.
43:00
Speaker 1: All So that's one way. What's the other way that
43:01
Speaker 1: we might see them? The other way, sort of the opposite,
43:04
Speaker 1: is to try to turn light into axions, Like instead
43:07
Speaker 1: of having axon turn into photons, turn that around. Take
43:11
Speaker 1: a beam of light and try to turn it into
43:13
Speaker 1: axions by putting the light. Yeah, like make light disappear. Yes,
43:17
Speaker 1: And so this experiment is called light shining through walls
43:21
Speaker 1: because you basically have a wall and a really strong
43:23
Speaker 1: magnetic field and then a beam of light and the
43:26
Speaker 1: ideas maybe the light will turn into axions which can
43:30
Speaker 1: then pass through the wall with no problem, which will
43:32
Speaker 1: then turn back into light and you can sort of
43:35
Speaker 1: like have your light, you know, passed through the wall
43:38
Speaker 1: by phase through the wall, by becoming an axon as
43:41
Speaker 1: it's going through the wall. I feel I feel like
43:43
Speaker 1: you're getting to the point where you're like, we need
43:45
Speaker 1: ideas or what's what's this is? This is a comic book?
43:47
Speaker 1: What there was a superhero that can go through walls?
43:50
Speaker 1: Oh that sounds like a great idea. Yeah, well it's
43:53
Speaker 1: pretty cool because if we figured out then we could
43:55
Speaker 1: actually build beams of light that go through walls. Right.
43:59
Speaker 1: So also sort a cool experiment because you just need
44:01
Speaker 1: like a light beam and a wall and then you
44:03
Speaker 1: just look for light making it through the wall. Right,
44:06
Speaker 1: So it's pretty dramatic, seething magical X rays. Yeah yeah,
44:12
Speaker 1: turning light and X rays making them penetrate just like
44:15
Speaker 1: X rays. And it's pretty fun, you know, to see
44:17
Speaker 1: these experiments. These are clever ideas, These are wacky ideas,
44:21
Speaker 1: and personally, I never expect these experiments to actually discover
44:24
Speaker 1: the axion. What though, isn't this your field? This is
44:29
Speaker 1: my field? Yes, but the accon has always seems sort of,
44:33
Speaker 1: I don't know, out there to me, like too crazy.
44:36
Speaker 1: An idea just feels like a little bit out there
44:38
Speaker 1: in left field, like yeah, it's a little too sutsy.
44:41
Speaker 1: Like I've read this interview with Helen Quinn, one of
44:44
Speaker 1: the two people who came up with the original idea,
44:47
Speaker 1: and even she's a little amused that this idea is
44:49
Speaker 1: still lacks She's like, I don't know what all the
44:52
Speaker 1: fuzzes about. Direct quote from her is Roberto and I
44:55
Speaker 1: spent a few months cooking up this theory, and now
44:57
Speaker 1: the experimentalist has spent forty years look for it. She's
45:01
Speaker 1: laughing at you, Daniel, It's like she's she's amused by you.
45:05
Speaker 1: The whole thing was a joke to begin with. What
45:07
Speaker 1: you guys doing wasting your time, Like that's what. We
45:10
Speaker 1: didn't give it a name. It was all a big
45:13
Speaker 1: practical joke, and then we planted the detergent for Frank
45:16
Speaker 1: whil Chick to find it using their time travel device, right,
45:20
Speaker 1: their magical X ray life. But it's fun, and you know,
45:24
Speaker 1: sometimes an idea can begin from a silly place, just exploring,
45:28
Speaker 1: just fuxing around with the math, and then turn into
45:31
Speaker 1: something real. I mean, if the axion is real and
45:33
Speaker 1: it solves these big open questions in physics, then that
45:37
Speaker 1: would have been a productive few months cooking up that
45:39
Speaker 1: crazy theory and productive forty years because you know, like
45:42
Speaker 1: the it's almost like the Higgs boson, right, do you
45:44
Speaker 1: predicted it? And like forty years later they found it. Yeah,
45:47
Speaker 1: it took almost fifty years to find the Higgs. So
45:49
Speaker 1: sometimes you come up with a theory for a particle
45:52
Speaker 1: that's really really hard to find. It's not always easy
45:55
Speaker 1: to go out and just like look for this thing,
45:56
Speaker 1: even if you know what it's supposed to do and
45:58
Speaker 1: how it's supposed to look, creating those conditions to find
46:01
Speaker 1: it is not always easy, especially if it's elusive. I mean,
46:04
Speaker 1: if it's the dark matter. Then it's been hiding for
46:06
Speaker 1: a long time, and and the stakes are pretty high, Like,
46:09
Speaker 1: if you find it, it would explain to so many things,
46:11
Speaker 1: including dark matter and antimatter and strong CP problem. Yeah,
46:15
Speaker 1: it would really close off a lot of big open
46:18
Speaker 1: questions in physics. So from that point of view, I
46:20
Speaker 1: sort of hope it is real because they would be
46:22
Speaker 1: a fascinating inside into the universe. And then, like as
46:25
Speaker 1: always with physics, when we get to ask the next question,
46:28
Speaker 1: like all right, well, why is there an axion? What
46:31
Speaker 1: does that mean? Is there another axion? You know, the
46:34
Speaker 1: whole spectrum of axion particles, And so the questions never
46:37
Speaker 1: really end right whenever there are lawyers that the Axon Corporation,
46:41
Speaker 1: they're like just waiting for you guys to discover it
46:43
Speaker 1: to give them that marketing boost in popular culture, or
46:47
Speaker 1: that's when they're going to see right there you go,
46:50
Speaker 1: They're gonna they're waiting, like, we own this. You can't
46:54
Speaker 1: you can't make X rays light special laser beams without us.
46:58
Speaker 1: That's right, We demand you pack up all your axions
47:00
Speaker 1: and boxes and send them to us immediately. Alright, Well,
47:04
Speaker 1: I think as usual, this just points to the things
47:06
Speaker 1: we don't know and how you know, science is actively
47:09
Speaker 1: still trying to explain the universe. That's right, And then
47:12
Speaker 1: a hundred years we could look back and think, what
47:14
Speaker 1: was it like before physics knew about the axion particle
47:18
Speaker 1: or the chlorox particle or whatever it is we're going
47:20
Speaker 1: to discover in twenty years, but before we know it,
47:23
Speaker 1: it's just an idea. It feels very different to be
47:26
Speaker 1: on the ignorance side of a discovery than on the
47:29
Speaker 1: knowledge side, because you never know what could turn out
47:31
Speaker 1: to be true. That's right, because the universe is no
47:33
Speaker 1: strangers to weirdness. All right, Well, we hope you enjoyed that.
47:37
Speaker 1: And the next time you're going down the grocery store
47:40
Speaker 1: laundry detergent, I'll look around. You might discover a new
47:44
Speaker 1: particle that explains the universe. Keep your eyes open, or
47:49
Speaker 1: at least discover a cool name for somebody else's good idea.
47:52
Speaker 1: You go. Thanks for joining us. Let's see you next time. Yeah,
48:03
Speaker 1: thanks for listening, and remember that. Daniel and Jorge Explain
48:06
Speaker 1: the Universe is a production of I Heart Radio. For
48:09
Speaker 1: more podcast for my heart Radio, visit the i Heart
48:12
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48:16
Speaker 1: favorite shows,