Latest / Daniel and Kelly’s Extraordinary Universe / Listener Questions 39: gravitons, antimatter and unified forces!

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Listener Questions 39: gravitons, antimatter and unified forces! · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Daniel, how's our podcast inbox looking like? These days?
0:12
Speaker 2: Always filled with such great questions from curious minds, young
0:16
Speaker 2: and old, sober and less than sober. Why do we
0:21
Speaker 2: get drunk called on the podcast? No more like ideas
0:24
Speaker 2: inspired by banana peels?
0:26
Speaker 1: No, I see drunk with curiosity about this amazing universe?
0:31
Speaker 1: Is that what you mean? Smoking in the fumes of
0:33
Speaker 1: scientific knowledge, becoming one with the universe, high on ideas
0:40
Speaker 1: about the cosmos? Put any good ideas in there? Any
0:43
Speaker 1: interesting questions or sparks that might inform your research?
0:47
Speaker 2: Hmm, Yes and no. No, in that I haven't exactly
0:50
Speaker 2: been mailed any promising theories of everything yet.
0:54
Speaker 1: But yes, in which way.
0:55
Speaker 2: Well, some listeners actually have useful skills and have volunteered
0:58
Speaker 2: to help out with my recent projects. I recently published
1:02
Speaker 2: a paper together with a listener about neutron stars.
1:04
Speaker 1: What did you pay them?
1:09
Speaker 2: I paid them in knowledge about the universe?
1:11
Speaker 3: Man?
1:13
Speaker 1: Is that a yes?
1:14
Speaker 4: And I no?
1:14
Speaker 1: Also, well, so we're not only disseminating signs, we're making
1:19
Speaker 1: signs here with our listeners.
1:21
Speaker 2: Yeah, depending on your definition of we, you.
1:24
Speaker 1: Mean, like, I don't count I'm getting paid. I'm a
1:27
Speaker 1: part of it.
1:27
Speaker 2: Well, when you and I published a paper about neutron stars,
1:30
Speaker 2: then you can get some credit.
1:31
Speaker 1: We have published a couple of books to say I
1:34
Speaker 1: definitely took the credit for that. But I guess that
1:36
Speaker 1: fits the professor model. They do all the work, you
1:39
Speaker 1: get the credit.
1:40
Speaker 2: Everybody gets a deep puff of knowledge about the universe.
1:43
Speaker 1: Well, I guess you can pay them in munchies later.
1:45
Speaker 2: Dorito's and ding Dong's moving signs forward.
2:03
Speaker 1: Hi am Warham and cartoonists and the creator of PhD comics.
2:06
Speaker 2: Hi, I'm Daniel. I'm a particle physicist and a professor
2:09
Speaker 2: at UC Irvine, and I make sure all of my
2:11
Speaker 2: researchers are.
2:12
Speaker 1: Paid in money or pats in the back.
2:15
Speaker 2: No, in money. I don't believe in unpaid internships, so
2:18
Speaker 2: everybody who participates and does some research definitely gets paid.
2:23
Speaker 1: Do you believe in summer undergrads underpaid internships?
2:29
Speaker 2: No, we provide funding for summer undergrads. Otherwise people who
2:33
Speaker 2: aren't independently wealthy couldn't afford to do research.
2:37
Speaker 1: Grad students a little underpaid. Wasn't there a big strike
2:39
Speaker 1: by grad students at the u SEE schools?
2:41
Speaker 2: There there was a massive strike by grad students and postdocs,
2:45
Speaker 2: and as a result, we are upping all of their
2:47
Speaker 2: salaries by a big chunk. So congrats on your successful
2:50
Speaker 2: unionization and activism.
2:52
Speaker 1: Which means you were underpaid them before.
2:54
Speaker 2: I think we're still underpaying them. I think we should
2:56
Speaker 2: pay them more absolutely.
3:00
Speaker 1: But anyways, welcome to our podcast, Daniel and Jorge Explain
3:03
Speaker 1: the Universe, a production of iHeartRadio.
3:05
Speaker 2: In which we try to pay it forward to the
3:07
Speaker 2: next generation of curious humans who want to understand the universe.
3:12
Speaker 2: All of science is driven forward just by people wondering
3:15
Speaker 2: and thinking and exploring the nature of the universe, and
3:17
Speaker 2: that's exactly what we do here on this podcast. We
3:21
Speaker 2: dive deep into the things that make us wonder, that
3:23
Speaker 2: make us curious, that make us ask questions about why
3:26
Speaker 2: the universe is this way and not some other way,
3:30
Speaker 2: and we do our best to answer those questions, or
3:32
Speaker 2: at least to introduce you to our current state of ignorance.
3:36
Speaker 1: It's right because ignorance and asking questions is how science
3:39
Speaker 1: starts and how science keeps going. Every time you answer
3:42
Speaker 1: question turnside, you feel ignorant about the next question, which
3:46
Speaker 1: you have to ask in order to try to get
3:48
Speaker 1: the answers.
3:48
Speaker 2: For like every four year old, we have discovered the
3:51
Speaker 2: power of the infinite Why why this? Why that? Well,
3:54
Speaker 2: why that other thing? We don't know if science is
3:57
Speaker 2: an infinite series of questions or if one day we
3:59
Speaker 2: will the answer which satisfies all of our curiosity. But
4:04
Speaker 2: until that day we can keep asking questions. And not
4:06
Speaker 2: just those of us getting paid to do science, but
4:08
Speaker 2: everybody out there asks questions and wonders about the universe
4:12
Speaker 2: and tries to figure it out. It's part of just
4:14
Speaker 2: living your life as a human being, building a model
4:17
Speaker 2: of the world around you and trying to figure out
4:20
Speaker 2: how to survive it.
4:21
Speaker 1: Do you think the universe gets annoyed at some point
4:23
Speaker 1: of humans asking so many pesky questions? You know, like
4:26
Speaker 1: the typical parent. At some point you want to be
4:28
Speaker 1: a good, supportive parent. But at some point it's like, because.
4:33
Speaker 2: I don't know, there's a lot of different ways you
4:34
Speaker 2: can go there, Like maybe the universe is set up
4:37
Speaker 2: as a mystery for us, you know. I was a
4:38
Speaker 2: guest on a podcast recently called The Universe is a
4:41
Speaker 2: video game which operates on the premise that not only
4:44
Speaker 2: is the universe a simulation, it's actively designed to be
4:47
Speaker 2: a video game, and we are basically playing it.
4:49
Speaker 1: Wait, like, the universe is an escape room, but if
4:52
Speaker 1: you escape the universe, where do you escape too?
4:54
Speaker 2: I don't know if it's an escape room, but there
4:55
Speaker 2: might be like a boss figure at some point you
4:57
Speaker 2: have to fight in the end to win the fi
5:00
Speaker 2: the knowledge of the universe.
5:01
Speaker 3: Mm.
5:02
Speaker 1: And then does it restart again basically as most Vida
5:05
Speaker 1: games do.
5:06
Speaker 2: I don't know, but I'd love to figure out the
5:08
Speaker 2: cheat code for the universe and like fast forward to
5:10
Speaker 2: the last level. That would be pretty fun.
5:12
Speaker 1: WHOA Like if you if you jump up, up, down, down, left, right, forward, backwards,
5:18
Speaker 1: do you somehow unlock some superpower?
5:21
Speaker 3: Mm hmm.
5:21
Speaker 2: But you know, there is one way in which science
5:23
Speaker 2: sort of is like a video game, except that we
5:26
Speaker 2: get to save the game. You know, when we start
5:28
Speaker 2: to understand the universe, we don't have to start from
5:30
Speaker 2: scratch the way you might when you load up a
5:32
Speaker 2: first video game. You get to start from where the
5:35
Speaker 2: last people figure it out. We are standing on the
5:37
Speaker 2: shoulders of so many giants who have understood so many
5:40
Speaker 2: things about the universe that we get to ask questions
5:43
Speaker 2: they may never even have considered.
5:45
Speaker 1: I feel like maybe you haven't played a Vita game
5:47
Speaker 1: since Atari. You know you can save games now, right,
5:52
Speaker 1: you can be able to do this since the Game Boy.
5:54
Speaker 2: I think it has been a while since I've played
5:56
Speaker 2: a classic video game. Actually, right now, I'm playing one
5:58
Speaker 2: suggested to me by a listener. It's called The Witness.
6:01
Speaker 2: You walk around an island and solve all sorts of
6:03
Speaker 2: fun geometric puzzles.
6:04
Speaker 1: But anyways, questions are how we move things forward, and
6:08
Speaker 1: questions is what we talk about here on the podcast,
6:10
Speaker 1: and sometimes those questions come from listeners.
6:13
Speaker 2: That's right. We don't just want you to be a
6:14
Speaker 2: passive participant falling asleep as we chat about the universe.
6:18
Speaker 2: We want to stimulate your curiosity. We want you to
6:21
Speaker 2: hear what we're saying, but try to fit it together
6:23
Speaker 2: in your own head so that it makes sense to you.
6:27
Speaker 2: And in that process, there might be some things that
6:29
Speaker 2: don't quite click together or that bump with other things
6:32
Speaker 2: that we told you or that you already knew. And
6:34
Speaker 2: doing physics is a process of trying to reconcile those
6:37
Speaker 2: conflicts of understanding how it can all click together into
6:40
Speaker 2: one understanding. So if you have questions about what you've
6:44
Speaker 2: heard or something else you read online, or things you're
6:46
Speaker 2: wondering about the universe banana pel inspired or not, Please
6:50
Speaker 2: write to us two questions at Danielandhorge dot com. We
6:54
Speaker 2: really mean it. We love your questions and we will
6:56
Speaker 2: respond to everybody.
6:57
Speaker 1: And if you make it to the next level, you
6:59
Speaker 1: get to fight dead as the final boss. Is how
7:02
Speaker 1: it works?
7:02
Speaker 2: Do you get to work with me on our research paper?
7:06
Speaker 1: Why is you they get to fight me as the
7:07
Speaker 1: final boss?
7:08
Speaker 2: Or maybe the universe is a game, but it's not
7:10
Speaker 2: one of those fighting or competitive games. Maybe it's one
7:12
Speaker 2: of those cooperative games.
7:14
Speaker 1: You know, you mean, like a like a giant citizen
7:16
Speaker 1: science project.
7:17
Speaker 2: Yeah, exactly.
7:19
Speaker 1: Wait are you saying a kademi is not competitive at all?
7:23
Speaker 2: Oh boy, there's a lot to dig into.
7:24
Speaker 1: There, don't they offer a giant price whoever discovers things first.
7:30
Speaker 2: It is competitive at many levels, of course, but in
7:32
Speaker 2: the end we are one community trying to unravel the
7:35
Speaker 2: nature of the universe. You do have to dangle a
7:38
Speaker 2: literal gold medal in front of some people to get
7:40
Speaker 2: them to work harder, but the goal in the end
7:43
Speaker 2: is cooperative. We do just want to understand the nature
7:46
Speaker 2: of this reality.
7:47
Speaker 1: Yeah, I guess you do share what you learn unless
7:50
Speaker 1: you're doing it for a company.
7:51
Speaker 2: I guess exactly. And so we ask questions. You ask questions,
7:53
Speaker 2: and we try to answer your questions. But sometimes people
7:56
Speaker 2: write in a really fun question that I think other
7:58
Speaker 2: people might want to hear the end to, or it
8:01
Speaker 2: just takes me a little bit of time to dig into,
8:03
Speaker 2: and so those questions get promoted to questions we talk
8:06
Speaker 2: about here on the podcast.
8:07
Speaker 1: Ooh, do you provide like a nice little sound effects
8:10
Speaker 1: like thing level up? Your question has leveled up plus
8:15
Speaker 1: one experience?
8:17
Speaker 2: I haven't yet, but I will now in the future.
8:19
Speaker 2: A great idea.
8:20
Speaker 1: Yeah, there you go, plus one PhD.
8:23
Speaker 2: Maybe I'll just sample your voice from what you just
8:25
Speaker 2: said and send that to them.
8:26
Speaker 1: Oh yeah, sure, I guess. I'm sure people want to
8:29
Speaker 1: listen to me more more every day. But today on
8:32
Speaker 1: the podcast, will he tackling listener questions number thirty nine? Ooh,
8:43
Speaker 1: what happens when we get to listener questions forty two?
8:46
Speaker 1: Are we going to reveal the final answer?
8:48
Speaker 2: We're gonna reveal the final question of everything in the universe?
8:52
Speaker 1: The wait The final question is forty two question mark.
8:55
Speaker 2: Nobody knows what the question is, right, that's the whole game.
8:58
Speaker 2: Figuring out what the question is really is a big
9:01
Speaker 2: part of science. I love that book for that reason.
9:03
Speaker 2: It's ridiculous, but it's also kind of.
9:05
Speaker 1: Deep, right right, Well, what if I just ask the
9:07
Speaker 1: question that comes after the answer forty two, like forty
9:11
Speaker 1: two or why forty two?
9:14
Speaker 2: What's forty one plus one?
9:16
Speaker 1: That's an answer, I guess, or that's a question exactly.
9:19
Speaker 2: This is like the Jeopardy version of science.
9:21
Speaker 1: But today we're answering questions from listeners, and we have
9:24
Speaker 1: three great ones here about gravitons, antime, matter, and the
9:29
Speaker 1: four forces and how they relate to quantum physics. So
9:34
Speaker 1: let's jump right in. Our first question is from Andres's
9:38
Speaker 1: a question about the Higgs boson.
9:40
Speaker 5: Hi, Daniel J.
9:40
Speaker 3: Jorge.
9:41
Speaker 5: This is Andres, and here's my question. Is the Higgs
9:44
Speaker 5: boson potentially the elusive graviton? On one hand, we have
9:48
Speaker 5: gravity as the only fundamental force without a known gouge boson,
9:52
Speaker 5: and on the other we have the Higgs boson, the
9:54
Speaker 5: boson that is not linked to a fundamental force. This
9:57
Speaker 5: is particularly intriguing given the relationship between and gravity and
10:01
Speaker 5: the fact that the Higgs field is associated with delivering
10:03
Speaker 5: master particles. Would be great to hear your thoughts on
10:06
Speaker 5: this topic. Thanks and congratulations for the success of the podcast.
10:10
Speaker 5: In the books by.
10:12
Speaker 1: All Right, awesome question for Andrez. We should just give
10:15
Speaker 1: them the Nobel Prize. You figured it.
10:16
Speaker 2: Out, ding, ding Ding. You have leveled up on dress.
10:20
Speaker 1: Oh, I think when you get the Nobel Prize, that's
10:22
Speaker 1: that's like the game over isn't unless unless you get
10:24
Speaker 1: to fight the ghost of Alfred Noble as the final boss.
10:28
Speaker 2: Well, it can't be the end of the game because
10:29
Speaker 2: some people have multiple Nobel Prizes, so you can just
10:32
Speaker 2: keep playing and keep winning.
10:33
Speaker 1: But don't you just play the same game? Kind of
10:36
Speaker 1: like the science doesn't get harder, does it? Once he's solved?
10:39
Speaker 1: Once you get the Nobel Prize.
10:41
Speaker 2: You can't just turn in the same paper and get
10:42
Speaker 2: another Nobel Prize and say, hey, this one earned me
10:45
Speaker 2: a Nobel Prize. Last time. You got to find something new.
10:48
Speaker 2: So yeah, you got to play the same game again
10:50
Speaker 2: but find a new solution.
10:51
Speaker 1: Well, it's still the same game. Kind of. There's some
10:54
Speaker 1: hope for winning multiple those but anyways, Andres has an
10:58
Speaker 1: interesting question. He's wondering the higgs boson is related to
11:01
Speaker 1: the graviton, because, as he said, the higgs boson is
11:05
Speaker 1: and the graviton seem related, but nobody seems to be
11:08
Speaker 1: maybe putting them in the same sentence as much.
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Speaker 2: Yeah, it's a really fun question because Andres is doing
11:14
Speaker 2: exactly what we suggest it, which is like trying to
11:16
Speaker 2: click pieces together. If gravity doesn't have a gauge boson
11:20
Speaker 2: and the higgs boson doesn't have a force, why can't
11:22
Speaker 2: we click those things together to make a single idea?
11:26
Speaker 2: And there's a great history of that kind of thing
11:28
Speaker 2: in physics, you know, clicking together electricity and magnetism to
11:31
Speaker 2: make electromagnetism, where each one has a missing bit that
11:34
Speaker 2: compliments the other. And even the higgs boson is an
11:37
Speaker 2: example of that, people clicking the weak force together with
11:41
Speaker 2: electromagnetism and noticing, ooh, there's a hole left over where
11:44
Speaker 2: a new particle sits. So Andres's idea is in the
11:47
Speaker 2: spirit of a great tradition. In this case, they don't
11:50
Speaker 2: quite fit together in the way that he's hoping.
11:52
Speaker 1: Well, you just boiled the answer, should we, you know,
11:56
Speaker 1: try to dig into it? A little bit. Let's dig
11:58
Speaker 1: into it. So I guess a lot of people might
11:59
Speaker 1: not be familiar with the Higgs boson and the gravit bond,
12:02
Speaker 1: So let's break each one of them down, one at
12:04
Speaker 1: a time.
12:04
Speaker 2: What is the Higgs boson? So the Higgs boson is
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Speaker 2: a particle, and it's a particle associated with a field
12:10
Speaker 2: that fills all of space. We call it the Higgs field.
12:13
Speaker 2: And like in the case of every particle, the particle
12:16
Speaker 2: is an excitation of that field. The field is just
12:18
Speaker 2: like a set of numbers through all of space. Every
12:20
Speaker 2: point in space has a number associated with it, and
12:23
Speaker 2: if at some point in space that number gets high,
12:26
Speaker 2: it gets excited. It's like a lot of energy there.
12:28
Speaker 2: We can call that a Higgs boson. But the exciting
12:30
Speaker 2: thing about the Higgs field is what it does to
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Speaker 2: other particles. It interacts with the other particles. So other
12:37
Speaker 2: particles like electrons or top quarks that are oscillations in
12:40
Speaker 2: their own fields, as they move through space, they interact
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Speaker 2: with the Higgs field, and the interaction changes how they move.
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Speaker 2: So a electron flies through space differently because it's interacting
12:50
Speaker 2: with the Higgs boson, and the interaction there is very
12:53
Speaker 2: different from any other kind of interaction. Doesn't just like
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Speaker 2: change the momentum of the electron the way a photon might.
12:59
Speaker 2: The higgson does something a little bit different. It makes
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Speaker 2: the electron move as if it had mass. So we
13:05
Speaker 2: say the Higgs boson gives mass to particles, that's what
13:08
Speaker 2: we mean. We mean the particles move through the universe
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Speaker 2: interacting with their Higgs field, and then interaction changes the
13:13
Speaker 2: way they move so that it looks as if they
13:15
Speaker 2: actually had mass. But really their mass comes from this interaction.
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Speaker 1: So when you say like it interacts as if it
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Speaker 1: has mass. For example, like the electron is just cruising
13:25
Speaker 1: along at a constant velocity, that means that it doesn't
13:29
Speaker 1: interact with the Higgs field, right, because something that is
13:32
Speaker 1: in motion, the mass tends to stay in motion, right,
13:35
Speaker 1: So for example that in that interaction nothing happens.
13:38
Speaker 2: Well, the true electron before it interacts with the Higgs
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Speaker 2: field doesn't have any mass. The electron on its own
13:43
Speaker 2: would be massless. Like if you turned off the Higgs
13:45
Speaker 2: field in the universe, the electron would be massless. And
13:48
Speaker 2: so an electron flying through space with constant velocity that
13:51
Speaker 2: requires the Higgs boson, because otherwise it would be moving
13:55
Speaker 2: at the speed of light.
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Speaker 1: But I guess once it gets a velocity it then
13:58
Speaker 1: it stays in that velocity.
14:00
Speaker 2: That's right, and that's inertia, right, we call this inertial mass.
14:03
Speaker 2: It's the property of objects to move in a straight
14:05
Speaker 2: line and to not accelerate unless a force acts on them.
14:09
Speaker 1: So then you're saying the interaction of the electron with
14:11
Speaker 1: the Higgs field is that it somehow the Higgs field
14:13
Speaker 1: pushes it along and keeps it going at a certain velocity.
14:16
Speaker 2: Or what what it does is it changes how that
14:18
Speaker 2: particle reacts to a push, Like because it has mass,
14:22
Speaker 2: it reacts differently to a force. You know, force equals
14:24
Speaker 2: mass times acceleration. So you have a particle with a
14:26
Speaker 2: lot of mass, you apply a force, it's not going
14:28
Speaker 2: to accelerate very much. If you have a particle with
14:31
Speaker 2: very very low mass, you apply that same force, it
14:34
Speaker 2: will accelerate much much more. So, the mass delivered by
14:37
Speaker 2: the Higgs boson changes how those particles will respond to
14:40
Speaker 2: a push. So if the electron had more mass, if
14:43
Speaker 2: it interacted more strongly with the Higgs field, then it
14:45
Speaker 2: wouldn't get as much acceleration for the same force. That's
14:48
Speaker 2: really what inertial mass is.
14:51
Speaker 1: So it sort of affects motions and pushing and pulling,
14:55
Speaker 1: but there's no force involved. I guess at least another
14:57
Speaker 1: fundamental forces are involved.
14:59
Speaker 2: Yeah, that's a bit of a feel plosophical point. And
15:01
Speaker 2: Dress says that the Higgs boson doesn't have a force
15:03
Speaker 2: associated with it. And you know, the Higgs boson is
15:05
Speaker 2: a boson, and the other bosons that we've talked about,
15:08
Speaker 2: like the photon, the W, the Z, the gluon, they're
15:12
Speaker 2: all associated with a force associated with electromagnetism or the
15:16
Speaker 2: weak force or the strong force. And so you can ask, like,
15:19
Speaker 2: does the Higgs boson have a force? And we don't
15:21
Speaker 2: often say that it does, but we don't really have
15:23
Speaker 2: a great reason for saying that. I mean, the Higgs
15:26
Speaker 2: boson does transfer momentum and kinetic energy the same way
15:30
Speaker 2: other bosons do. The reason we don't say it's the
15:32
Speaker 2: mediator of a force is that it's not the mediator
15:35
Speaker 2: of like a fundamental force the way electromagnetism and the
15:39
Speaker 2: weak force and the strong force are those are fundamental
15:42
Speaker 2: in a slightly different way than a force that you
15:44
Speaker 2: would associate with the Higgs boson.
15:46
Speaker 1: Is okay, So then the Higgs boson is a boson,
15:49
Speaker 1: but it doesn't have a force associated with it. It
15:51
Speaker 1: just kind of interacts with particles in order to give
15:55
Speaker 1: them the effect of inertia. All right, Now, let's dig
15:57
Speaker 1: into the graviton. What is the graviton or does it
16:00
Speaker 1: even exist?
16:01
Speaker 2: Yeah, so the graviton is a hypothetical particle. We don't
16:05
Speaker 2: know if gravity is a classical theory, meaning that it
16:09
Speaker 2: ignores quantum mechanics, or if it's a quantum theory, meaning
16:12
Speaker 2: that it respects the rules of quantum mechanics, the uncertainty,
16:16
Speaker 2: the fact that things have to be discretized. You know,
16:18
Speaker 2: you can have like one photon or seven photons, but
16:21
Speaker 2: not three point one two photons. These kinds of rules,
16:24
Speaker 2: those quantum rules apply to all of the other forces, electromagnetism,
16:29
Speaker 2: strong force, the weak force, even the Higgs field. These
16:32
Speaker 2: are all quantum theories, but gravity, so far, our theory
16:35
Speaker 2: of it is general relativity, which is not a quantum theory.
16:39
Speaker 2: But there are versions of gravitational theories that try to
16:42
Speaker 2: make it into a quantum force, to say maybe gravity
16:46
Speaker 2: isn't the curvature of space time like Einstein described. Maybe
16:49
Speaker 2: it's a quantum force like the other forces like the
16:52
Speaker 2: strong force and electroweak, et cetera. And if that's the case,
16:55
Speaker 2: it would have a boson. That boson would be called
16:58
Speaker 2: the graviton. But that's hypothetical because we haven't yet seen
17:02
Speaker 2: the graviton. Nobody's observed that it's out there that exists
17:05
Speaker 2: in our universe. It's just like, if gravity is a
17:08
Speaker 2: quantum force, there should be a boson, and this is
17:10
Speaker 2: the name of it.
17:11
Speaker 1: Is that necessarily true though, Like you know, it sounds
17:14
Speaker 1: like you can have a boson without a force. Can
17:16
Speaker 1: you have a force without a boson, or something like
17:19
Speaker 1: a force or that gives you the effect of a
17:21
Speaker 1: force without actually having a boson.
17:23
Speaker 2: It's a great question. You can't. I mean, what a
17:26
Speaker 2: force really is is the transmission of energy through a field,
17:29
Speaker 2: and that's going to come in the form of a ripple,
17:32
Speaker 2: and we can call that ripple a particle. Also, all
17:34
Speaker 2: these forces that we're talking about, these are called gauge forces,
17:37
Speaker 2: and they exist to protect some symmetry in the universe.
17:41
Speaker 2: We have a whole episode on this really interesting mathematical
17:43
Speaker 2: principle called local gauge invariance, which requires that this weird
17:48
Speaker 2: number through all of space is preserved and the forces
17:52
Speaker 2: exist in order to preserve that. So like the photon
17:54
Speaker 2: exists to preserve this symmetry in electromagnetism, and the other
17:58
Speaker 2: bosons existent that symmetry. So if we build gravity in
18:02
Speaker 2: the same way, if we make a quantum theory of
18:04
Speaker 2: gravity and require the same sort of gauge invariance that
18:08
Speaker 2: we do for the other fields, then it would have
18:10
Speaker 2: a graviton to sort of mediate that momentum and preserve
18:13
Speaker 2: the local gauge symmetry. There are other theories of quantum
18:16
Speaker 2: gravity that don't have a graviton, but they don't treat
18:19
Speaker 2: the force as a quantum theory like efforts to quantize
18:22
Speaker 2: space itself. Like loop, quantum gravity doesn't necessarily have a graviton,
18:26
Speaker 2: but theories that make gravity to a quantum force they
18:29
Speaker 2: do have a graviton.
18:30
Speaker 1: Oh I see, So a graviton is the particle that
18:33
Speaker 1: would transmit the gravitational quantum force, but it's maybe not
18:37
Speaker 1: necessary in order to marry quantum physics and gravity. In
18:41
Speaker 1: general relativity, you don't need the graviton necessarily.
18:43
Speaker 2: That's right. In some theories of quantum gravity, you have
18:46
Speaker 2: a graviton, but again it's just theoretical, like we haven't
18:49
Speaker 2: ever seen the graviton because gravity is so weak, right,
18:52
Speaker 2: gravity is so much weaker than the other forces. It's very,
18:55
Speaker 2: very difficult to observe the graviton. It would require an
18:58
Speaker 2: enormous particle accelerator.
18:59
Speaker 1: All right, well, now let's dig into Andres's real question,
19:02
Speaker 1: which is, could the Higgs boson be the graviton with
19:06
Speaker 1: it all make it click together and win a noble
19:09
Speaker 1: price or two. So let's dig into that, but first
19:11
Speaker 1: let's take a quick break. All right, we're answering listener
19:26
Speaker 1: questions here today, and our first question came from Andres,
19:29
Speaker 1: who asked, is the Higgs boson the graviton? Which is
19:32
Speaker 1: a really tantalizing question, And so we talked about what
19:35
Speaker 1: the Higgs boson is and what the graviton is or
19:38
Speaker 1: could be, and so now the question is are they
19:40
Speaker 1: the same? And it sort of sounds like maybe the
19:42
Speaker 1: answer is no, because we talked about how the Higgs
19:44
Speaker 1: boson is about inertial mass, but the graviton is about gravity,
19:48
Speaker 1: and those two things are not necessarily the same.
19:50
Speaker 2: Yeah, it's tempting to group them together in your mind
19:53
Speaker 2: because they both do seem to be related to mass,
19:56
Speaker 2: but that doesn't mean that they actually play the same role. Right, So,
20:00
Speaker 2: as you say, the Higgs boson gives you inertial mass,
20:02
Speaker 2: but it's actually not the only source of inertial mass.
20:05
Speaker 2: It doesn't have a monopoly on giving mass to things.
20:08
Speaker 2: Remember that mass is just a measure of how much
20:11
Speaker 2: internal stored energy there is in something, and that energy
20:15
Speaker 2: can come from interactions with the Higgs field, but it
20:17
Speaker 2: can also come in other ways. It can come from
20:20
Speaker 2: other fields. Like the proton is made of quarks, and
20:23
Speaker 2: those quarks have very very small masses, but the proton
20:26
Speaker 2: is really massive. Most of the mass of the proton
20:29
Speaker 2: doesn't come from the mass of the quarks that make
20:31
Speaker 2: it up, but from the energy in the strong force
20:34
Speaker 2: that binds those quarks together, and so it's mostly that
20:38
Speaker 2: stored energy. So the Higgs boson does have a relationship
20:41
Speaker 2: with mass, but not a monopoly on it. There are
20:43
Speaker 2: other ways to get mass, so mass is sort of
20:46
Speaker 2: independent from the Higgs mechanism itself.
20:49
Speaker 1: How do the other kinds of masses get inertia, then
20:52
Speaker 1: we have no idea.
20:53
Speaker 2: Right, yeah, exactly. We say that the Higgs field interacts
20:56
Speaker 2: with these particles and so it sort of stores internal energy.
21:00
Speaker 2: Why internal stored energy leads to inertia is sort of
21:03
Speaker 2: a deeper mystery, right, And you alluded to it earlier
21:07
Speaker 2: when you talked about the difference between inertial mass and
21:09
Speaker 2: gravitational mass. And in Newton's time that was a mystery.
21:12
Speaker 2: We had the inertial mass, which was m in f
21:15
Speaker 2: equals ma that told us how things responded to pushes,
21:19
Speaker 2: and then we had the gravitational mass in his gravitational formula.
21:22
Speaker 2: And according to Newton, these are two different concepts, and
21:25
Speaker 2: it was sort of miraculous that everything seemed to have
21:27
Speaker 2: the same inertial and gravitational mass. Einstein tells us that
21:30
Speaker 2: those two things are the same concept, and that's basically
21:33
Speaker 2: his whole theory of gravity, that acceleration due to gravity
21:36
Speaker 2: really is inertial motion, and there is no gravitational force,
21:41
Speaker 2: there is no gravitational mass. There's just the inertial mass,
21:43
Speaker 2: and things move through space because space is curved and
21:46
Speaker 2: all that good stuff. So general relativity sort of unifies
21:49
Speaker 2: those two concepts.
21:50
Speaker 1: So then why couldn't the graviton be the Higgs because
21:52
Speaker 1: the graviton is about gravity and not inertial mass.
21:55
Speaker 2: Yeah, exactly, the graviton doesn't give inertial mass to objects.
21:58
Speaker 2: You know, the graviton in this case would sort of
22:01
Speaker 2: like bend space. Sort of weird. You have a quantum
22:03
Speaker 2: theory with emitted particles, and then those particles themselves are
22:07
Speaker 2: responsible for curving space, so you have like quantum field
22:11
Speaker 2: theory on curved space, but that can affect massless particles.
22:14
Speaker 2: So for example, gravity has effect on massless particles like photons.
22:19
Speaker 2: Gravity bend space, right in Einstein's theory of relativity, masses
22:24
Speaker 2: bend space. I mean, even in a quantum version of gravity,
22:27
Speaker 2: you would have to bend space with these gravitons and
22:29
Speaker 2: photons moving through that bend space will curve, and so
22:33
Speaker 2: there's no involvement of the Higgs boson there at all.
22:35
Speaker 2: There's no inertial mass on these objects, and yet they
22:38
Speaker 2: still do move through curved space. So gravity does things
22:42
Speaker 2: that the Higgs boson can't do.
22:43
Speaker 1: All right, So then I guess the answer is that
22:45
Speaker 1: it's not the same thing gravity and inertia. So then
22:47
Speaker 1: the Higgs boson can't be the graviton or is that
22:50
Speaker 1: still possible.
22:51
Speaker 2: No, it's not still possible. I mean there is a
22:53
Speaker 2: close connection between gravity and inertia and general relativity. But
22:56
Speaker 2: you can again have gravitational effects on objects with no MA,
23:00
Speaker 2: and you can have mass even if there wasn't gravity.
23:03
Speaker 2: Like an electron flying through totally empty space, as you
23:06
Speaker 2: said earlier, is still going to have inertia even if
23:08
Speaker 2: it doesn't feel the gravity of anything. So these really
23:11
Speaker 2: are separate concepts and require separate particles.
23:15
Speaker 1: It is pretty fascinating to think that quantum mechanics, like
23:18
Speaker 1: this huge theory that we have totally disregards or doesn't
23:22
Speaker 1: take gravity into account, like gravity as far as quantum
23:24
Speaker 1: mechanics knows, gravity doesn't exist, right.
23:27
Speaker 2: Yeah, that's right. Our quantum field theory that describes these
23:29
Speaker 2: other forces can't really grapple with gravity. I mean, we
23:32
Speaker 2: can do quantum field theory in curved space. If you
23:35
Speaker 2: have a reason why space is curved, you can do
23:37
Speaker 2: those calculations. But we don't know how to make gravity
23:40
Speaker 2: into a quantum theory. Like we have this idea of
23:42
Speaker 2: a graviton, but when you do the calculations and quantum theory,
23:45
Speaker 2: everything blows up and you get nonsense answers. So we
23:47
Speaker 2: don't know how, like mathematically, how to build a quantum
23:50
Speaker 2: theory of gravity. Yet it's a huge open area of research.
23:54
Speaker 1: All right, So then the answer under this is not
23:56
Speaker 1: really Unfortunately game over for you. You have to start over.
24:00
Speaker 1: Can you at least send them another quarter or something?
24:02
Speaker 2: Yeah, you get three more lives undress.
24:08
Speaker 1: That's moore than most of us get. I guess my
24:10
Speaker 1: last question is you know, if you beat the Higgs boson,
24:12
Speaker 1: do you then get to the final boss on?
24:17
Speaker 2: Nice? I can't believe you didn't see that coming.
24:21
Speaker 1: All right, well, let's get to our next question, and
24:23
Speaker 1: this one comes from Richard, and it's about matter and antimatter.
24:27
Speaker 4: I have a question regarding how particles are assigned to
24:30
Speaker 4: the matter versus antimatter categories. In popular science, matter and
24:34
Speaker 4: antimatter are defined as opposites with the same properties but
24:38
Speaker 4: opposite charges. But that does not indicate how to determine
24:41
Speaker 4: which of a pair of opposites is matter and which
24:43
Speaker 4: is antimatter. For a single particle, the distinction is arbitrary,
24:47
Speaker 4: but not for a group. If the categories of matter
24:49
Speaker 4: or antimatter have some relational meaning between the particles. For instance,
24:53
Speaker 4: suppose tomorrow we discovered two new particles X and Y,
24:57
Speaker 4: which are identified as matter antimatter pairs. How would physicists
25:01
Speaker 4: decide which of these particles is categorized with the other
25:04
Speaker 4: matter particles and which are to be categorized as antimatter.
25:08
Speaker 4: I've heard you speak about the asymmetry of the week
25:11
Speaker 4: fourth with respect to how it interacts with left or
25:14
Speaker 4: right handed particles differently from matter than antimatter. So would
25:18
Speaker 4: this be the determining factor? What if a particle did
25:21
Speaker 4: not interact with the weak force? Is there something more
25:24
Speaker 4: basic in the standard model which determines this. A related
25:27
Speaker 4: question is whether or not there is any flexibility in
25:29
Speaker 4: the way we categorize the currently known particles. For instance,
25:33
Speaker 4: can we flip the quarks matter antimatter categories so an
25:37
Speaker 4: adam would consists of a quote unquote antimatter nucleus and
25:42
Speaker 4: a matter set of electrons Or would this lead to
25:45
Speaker 4: a complication in other Standard model rules which would seem
25:48
Speaker 4: less elegant and simple.
25:50
Speaker 1: All right, awesome question from Richard. I feel like he
25:52
Speaker 1: wrote out a whole thesis here for us. Does he
25:55
Speaker 1: get an automatic Noble Prize?
25:57
Speaker 2: Maybe he gets the anti Nobel Prize for sending an
26:00
Speaker 2: answer instead of a question.
26:01
Speaker 1: Ooh, I want an anti Nobel prize. What do I
26:04
Speaker 1: anti have to do?
26:05
Speaker 2: I don't know. But when you get it, don't let
26:06
Speaker 2: it touch your Nobel Prize.
26:08
Speaker 1: I think we're safe from that because I don't have one.
26:12
Speaker 1: But it's an interesting question about matter and antimatter, I
26:15
Speaker 1: guess basically his question is why do we call some
26:18
Speaker 1: things matter and something's antimatter? Like how do we know
26:21
Speaker 1: if you find a new particle whether you should call
26:24
Speaker 1: it a matter particle or an antimatter particle.
26:27
Speaker 2: Yeah, it's a great question. I love this. He's wondering,
26:30
Speaker 2: like how we built these ideas and how much freedom
26:32
Speaker 2: is there really? And are these choices arbitrary or are
26:35
Speaker 2: they required by some other sort of mathematical structure. Great question.
26:39
Speaker 1: Cool, So let's dig into it, Daniel, what is antimatter?
26:42
Speaker 2: So it turns out that for every kind of particle
26:45
Speaker 2: that we know about electron, a core, commuon, there's another
26:49
Speaker 2: kind of particle that can exist in the universe that's very,
26:52
Speaker 2: very similar to that particle. Except that it has the
26:56
Speaker 2: opposite quantum numbers. So if you have a particle with
26:59
Speaker 2: negative one charge, it's anti particle has positive oid charge.
27:03
Speaker 2: And if it's a particle with red color for the
27:06
Speaker 2: strong force, there's another version of it with anti red color,
27:09
Speaker 2: for example. So all the quantum numbers of the particle,
27:13
Speaker 2: the charges, for example, associate with each of the forces,
27:16
Speaker 2: so charge, weak, hypercharge, strong color are flipped for the
27:20
Speaker 2: anti matter particle. And so this is something that the
27:23
Speaker 2: universe can do. It's like a feature of the universe,
27:26
Speaker 2: but it's not something that exists very often, like the
27:29
Speaker 2: stuff that we see around us is all made of matter.
27:31
Speaker 2: I'm made of matter, you're made of matter. But this
27:33
Speaker 2: is something the universe has the capacity for, even if
27:36
Speaker 2: it doesn't exist very often in reality.
27:40
Speaker 1: Now, are those the only quantum numbers, because is in
27:42
Speaker 1: like spin quantum number. You can flip that and not
27:45
Speaker 1: get antimatter, right.
27:46
Speaker 2: That's right. But an electron can have like positive or
27:48
Speaker 2: negative spin, so it's not like an inherent property of
27:51
Speaker 2: the electron to be positive or negative, and positrons, the
27:54
Speaker 2: anti particle of the electron can also have positive or
27:57
Speaker 2: negative spin, and the kind of spin they can have
28:00
Speaker 2: is the same. Like both of them are spin one
28:03
Speaker 2: half particles, meaning they're fermions. So that's not different between
28:06
Speaker 2: matter and antimatter. The spin structure is the same.
28:09
Speaker 1: Okay, I guess I'm just saying, like the difference between
28:12
Speaker 1: matter and antimatter is if you flip some of the
28:14
Speaker 1: quantum numbers, specifically I guess the ones that you would
28:17
Speaker 1: call charge, right, like electrical charge in terms of the forces.
28:21
Speaker 2: Yes, exactly, you flip the charges of the particle.
28:24
Speaker 1: Which are sort of the numbers associated with forces.
28:27
Speaker 2: Right exactly. And interestingly, you don't flip the mass, Like
28:31
Speaker 2: the positron doesn't have negative mass, and you might think
28:34
Speaker 2: it would if gravity was also a quantum force and
28:37
Speaker 2: you thought of mass as like the charge in a
28:40
Speaker 2: gravitational force, but you don't, and gravity we don't know
28:43
Speaker 2: if it's a quantum force. But anyway, positron and an
28:46
Speaker 2: electron have the same.
28:47
Speaker 1: Mass, although it is possible, right, I mean, theoretically it
28:51
Speaker 1: is possible for something to have negative mass, right kind
28:54
Speaker 1: of like the theories don't prevent it, which has never
28:57
Speaker 1: seen it.
28:57
Speaker 2: Well, we don't fundamentally understand what mass is. As we said,
28:59
Speaker 2: Earth and there are some theories of negative mass particles,
29:03
Speaker 2: though that raises all sorts of other complicated issues, But
29:06
Speaker 2: we did a whole podcast about that, so people who
29:08
Speaker 2: are curious about negative mass particles dig into that. But
29:12
Speaker 2: in our universe, we've never seen any negative mass particles,
29:14
Speaker 2: and the antimatter particles we have seen all do have
29:17
Speaker 2: positive mass, though we don't actually know what the gravitational
29:21
Speaker 2: force is on antimatter. We recently did a podcast episode
29:24
Speaker 2: about that, whether antimatter falls up or down, it might
29:28
Speaker 2: have positive mass but repulsive gravity. That would be fascinating,
29:32
Speaker 2: all right.
29:33
Speaker 1: But in general, if you have a particle and you
29:35
Speaker 1: flip all of its charges to charge the hypercharge and
29:38
Speaker 1: the color, then you get the anti matter version of
29:43
Speaker 1: that particle. That's kind of the rule, or that's kind
29:46
Speaker 1: of what the anti matter is exactly.
29:48
Speaker 2: And it's part of this beautiful trend in the universe
29:51
Speaker 2: that we have these symmetries, Like the universe doesn't just
29:54
Speaker 2: have like, oh, here's a kind of particle, there's a
29:56
Speaker 2: kind of particle. It seems to like to reflect each
29:58
Speaker 2: kind of particle in multiple ways, Like the electron has
30:01
Speaker 2: the muon version of it, it also has the antimatter
30:04
Speaker 2: version of it. So there's these weird reflections of each particle.
30:08
Speaker 2: It can exist in multiple ways, which might be like
30:11
Speaker 2: hints about what's going on inside these particles. Why there
30:15
Speaker 2: are these symmetries. We just don't really understand it.
30:18
Speaker 1: A little bit like how the proton is a plus
30:21
Speaker 1: one charge and the neutron has a zero charge, But
30:24
Speaker 1: it's all because of the quarts inside of them and
30:26
Speaker 1: how they're arranged exactly.
30:28
Speaker 2: It might be that positrons and electrons are actually built
30:30
Speaker 2: out of the same bits, just organized in different ways,
30:33
Speaker 2: and organize them in another way and you get a muon.
30:35
Speaker 2: We just don't know what's inside these particles, but it's
30:37
Speaker 2: a big screaming clue that there's some interesting internal structure
30:41
Speaker 2: that we haven't yet discovered. But right now all we
30:43
Speaker 2: can do is sort of look at it, categorize it,
30:45
Speaker 2: describe it. We haven't been able to explain these phenomena
30:48
Speaker 2: at all all.
30:49
Speaker 1: Right, So, now, if I have an electron and I
30:51
Speaker 1: flip its charge, I get the positron, which is the
30:54
Speaker 1: antimatter version of the electron. But if I have another
30:57
Speaker 1: particle that has hypercharge and I flip that charge, and
31:00
Speaker 1: that becomes the anti matter particle version of that particle. Right,
31:03
Speaker 1: But some charges have like three charges, So how do
31:06
Speaker 1: you flip those?
31:06
Speaker 2: Yeah, great question. Well, you know the color, there are
31:09
Speaker 2: three options. There are red, green, and blue, but there's
31:11
Speaker 2: also anti red, anti blue, and anti green. So you
31:15
Speaker 2: can take a red quark and flip it to an
31:17
Speaker 2: anti red quark.
31:19
Speaker 1: So really there's six colors in terms of charge. Right,
31:23
Speaker 1: because plus and minus for the electron counts as two
31:26
Speaker 1: kinds of charges. It sounds like color you can have
31:29
Speaker 1: them six kinds of charges.
31:30
Speaker 2: Yeah, I suppose that's true. Makes you wonder what anti
31:33
Speaker 2: blue looks like. Maybe it's anti bluetiful.
31:35
Speaker 1: Well, that's a colorful analogy.
31:37
Speaker 2: I got a whole rainbow of analogies over you're here.
31:39
Speaker 1: Well, at least it's not adult or a gray theory there.
31:43
Speaker 1: It's no gray area there, right, So then I guess
31:45
Speaker 1: Richard's question is like, how do you know something is
31:48
Speaker 1: matter or you should be calling it antimatter? Like he said,
31:51
Speaker 1: if you discover a new particle and it has you know,
31:56
Speaker 1: plus this or minus a, how do you know whether
31:58
Speaker 1: you should call it matter or anti matter?
32:00
Speaker 2: Yeah, it's a great question. And to dig into it,
32:02
Speaker 2: we have to think about like the differences between matter
32:05
Speaker 2: and antimatter, like what is the difference? Why do both
32:08
Speaker 2: of them exist? Is it really totally symmetric? And we know,
32:12
Speaker 2: of course, the answer is that it's not totally symmetric.
32:14
Speaker 2: I mean, I'm made of matter. You're made of matter.
32:16
Speaker 2: The Earth and the Solar System and the galaxy are
32:18
Speaker 2: made of matter. There's little bits of antimatter created here
32:21
Speaker 2: and there in collisions, but mostly we're made of matter,
32:25
Speaker 2: and the universe as a whole seems to be made
32:27
Speaker 2: of matter instead of antimatter. So that tells you right
32:30
Speaker 2: off the bat that they can't be symmetric because it's
32:32
Speaker 2: an imbalance. There's a lot more matter than antimatter, so
32:35
Speaker 2: there's got to be some difference between matter and antimatter,
32:38
Speaker 2: and that's not something that we understand, Like there are
32:41
Speaker 2: a few processes out there that seem to prefer making
32:43
Speaker 2: matter instead of antimatter, but we still can't explain how
32:46
Speaker 2: you could have started the universe in a symmetric state
32:49
Speaker 2: of equal amounts of matter and antimatter and ended up
32:52
Speaker 2: with only matter left over, Like we just don't understand that.
32:55
Speaker 2: So there is some imbalance between the two, but we
32:58
Speaker 2: still don't understand it. And the short answer to your
33:01
Speaker 2: question is that matter is what we call the stuff
33:03
Speaker 2: that's around you know, the things that we find around us.
33:06
Speaker 2: Electrons we call them matter because they're here, and positrons
33:10
Speaker 2: we call them antimatter because they're not.
33:12
Speaker 1: So theoretically, as far as we know, there is a symmetry.
33:15
Speaker 1: There's no difference between matter and antimatter. You're saying, like, experimentally,
33:20
Speaker 1: from what we can see out there, there's just a
33:21
Speaker 1: whole bunch more of what we call matter than there
33:24
Speaker 1: is of what we call antimatter.
33:26
Speaker 2: Yeah, that's almost true. To be more precise, theoretically, there
33:29
Speaker 2: is a small difference, Like in the Standard model, there
33:31
Speaker 2: are a few processes we call them CP violation that
33:34
Speaker 2: break the symmetry between matter and antimatter, but they're really
33:37
Speaker 2: really small effects. They can't explain the large difference we
33:41
Speaker 2: see experimentally. So experimentally we see a large difference. Theoretically
33:45
Speaker 2: we expect a very small difference and that we can't explain.
33:48
Speaker 1: So then really you're saying, what we call matter and
33:50
Speaker 1: not antimatter is kind of what we see. The most
33:54
Speaker 1: of out there in the universe.
33:55
Speaker 2: Yeah, exactly, And it could be that there are galaxies
33:59
Speaker 2: out there of antimatter, really really far away, beyond our
34:02
Speaker 2: ability to probe. There could be whole galaxies made out
34:05
Speaker 2: of antimatter, and they would also emit photons and shine
34:08
Speaker 2: at us. Some of the galaxies seen by the James
34:10
Speaker 2: Webspace Telescope might be made of antimatter, and aliens in
34:15
Speaker 2: those galaxies would call their antimatter matter because it's what
34:18
Speaker 2: they're made out of. So it's really just sort of
34:20
Speaker 2: like a relative arbitrary label.
34:22
Speaker 1: Whoa like, we could be the antimatter versions, right, or
34:26
Speaker 1: like maybe we are the villains, We're the evil plants.
34:29
Speaker 2: Yeah, we have some cool techniques to figure out if
34:31
Speaker 2: distant things are made of matter or antimatter. Basically, we
34:35
Speaker 2: look for regions in between our island of matter and
34:39
Speaker 2: any potential island of antimatter where the particles radiated by
34:42
Speaker 2: those galaxies would slam into each other and cause bright flashes.
34:45
Speaker 2: We haven't seen any of those, which convinces us that
34:48
Speaker 2: the neighborhood at least isn't made of antimatter. But this
34:51
Speaker 2: is a limit to how far out we can look
34:53
Speaker 2: so there might be islands of antimatter out there, just
34:55
Speaker 2: sort of beyond where we've seen.
34:58
Speaker 1: I think that's the name of a new Netflix reality show,
35:01
Speaker 1: Antimatter Island.
35:03
Speaker 2: Every week somebody gets annihilated.
35:07
Speaker 1: Or at least ridiculed in public. Well, then, I guess
35:10
Speaker 1: Richard's question is, like, if you find a new particle
35:12
Speaker 1: out there, like a totally new particle, not relate to
35:16
Speaker 1: any of the ones that we know or see around,
35:18
Speaker 1: how do you know whether you should call it a
35:20
Speaker 1: matter particle or an antimatter particle.
35:22
Speaker 2: Yeah, And the answer is that it's arbitrary. It doesn't
35:25
Speaker 2: really matter, you know, Like what we call matter is
35:28
Speaker 2: just one side of the coin, and what we call
35:30
Speaker 2: antimatter is just the other side. It doesn't really have
35:33
Speaker 2: any importance. Like, we could all decide to call the
35:37
Speaker 2: muon antimatter and to its antiparticle matter, right, We could
35:42
Speaker 2: do that and it wouldn't create any problems theoretically, it
35:44
Speaker 2: wouldn't change the way we do any calculations, doesn't really
35:48
Speaker 2: affect anything. It's just the name we give things. We
35:51
Speaker 2: like to be consistent, so we look for patterns. We say, well,
35:54
Speaker 2: the electron, we start by calling that matter. The muon
35:57
Speaker 2: will call that matter also because has the same charges
35:59
Speaker 2: as the elect and so the tow also, right, and
36:02
Speaker 2: we'll say the proton is matter, and so the quarks.
36:04
Speaker 2: It's made out of our matter. But we could have
36:07
Speaker 2: made other choices. We could say, oh, the quarks are antimatter, right,
36:10
Speaker 2: that could be cool. We wouldn't create any problems. But
36:13
Speaker 2: the quarks, you know, they have the same weak charges
36:15
Speaker 2: as the electron, So we'd like to say that those
36:17
Speaker 2: things are matter, just sort of like out of consistency.
36:20
Speaker 2: But it's not a strong requirement, doesn't really change anything.
36:23
Speaker 2: So for example, if we discover dark matter and there
36:26
Speaker 2: are two versions of it where one is the anti
36:28
Speaker 2: particle of the other, Richard's question is a great one.
36:30
Speaker 2: Which one do we call matter? In some sense it
36:33
Speaker 2: would be totally arbitrary, But if there's like a lot
36:35
Speaker 2: more of one of them and a lot less of
36:37
Speaker 2: the other, we probably call it the dominant one.
36:39
Speaker 1: Matter interesting, all right, So then that's the answer for Richard.
36:44
Speaker 1: You know, it's kind of arbitrary what we call matter
36:47
Speaker 1: and antimatter. We go with matter for the stuff we're
36:49
Speaker 1: made out of, and the stuff that looks like the
36:51
Speaker 1: stuff we're made out of, right, And if we alread
36:54
Speaker 1: discover a new particle, we would just have to I guess,
36:56
Speaker 1: either flip a coin or see which one is more popular.
37:00
Speaker 1: I guess we'll go by popularity.
37:01
Speaker 2: That what you're saying, Yeah, it doesn't really matter in
37:04
Speaker 2: the end, And there's a possibility, of course, So we
37:06
Speaker 2: also discover a new particle and it doesn't have an
37:09
Speaker 2: anti particle. We think there might be versions of matter
37:12
Speaker 2: out there that are called Mayorana particles. Check out our
37:15
Speaker 2: podcast episode about that that are their own anti particles,
37:18
Speaker 2: and neutrinos might even be mairana particles. They might not
37:22
Speaker 2: be anti neutrinos, so we might not have to make
37:25
Speaker 2: that decision.
37:25
Speaker 1: All right, I guess it's a very democratic endeavor science.
37:29
Speaker 1: Whoever gets the most votes gets to decide what they're called.
37:32
Speaker 2: Whatever happens, I'm sure we'll argue about it all rights.
37:35
Speaker 1: To get to our last question of the day, it's
37:37
Speaker 1: an interesting question about the four forces and how they
37:40
Speaker 1: unify with quantum mechanics. So let's dig into that. But
37:43
Speaker 1: first let's take another quick break. All right, we're talking
37:59
Speaker 1: about listener questions here, questions from listeners and their amazing curiosity.
38:04
Speaker 1: Our last question comes from Ryan, who is a question
38:07
Speaker 1: about unifying the four fundamental forces?
38:10
Speaker 3: Hi, Daniel, and Jorge. I'm a big fear of the show.
38:14
Speaker 3: I started listening in high school and now I'm a
38:17
Speaker 3: college student. I wrote this question in a while ago,
38:19
Speaker 3: but your response email went in the spam and I
38:22
Speaker 3: finally saw it now, So now finally ask the question
38:27
Speaker 3: why does it matter that the four fundamental forces of physics,
38:32
Speaker 3: the like strong force, weak force, electromagnetic and gravity are unified?
38:38
Speaker 3: And then kind of similar to that, why is does
38:41
Speaker 3: classical mechanics need to be unified with quantum mechanics That
38:45
Speaker 3: we know they all work in their own realms, so
38:48
Speaker 3: why do they have to be unified?
38:50
Speaker 1: All right? Awesome question from Ryan, who is a longtime listener.
38:54
Speaker 1: I was kind of glad he said he's in college
38:55
Speaker 1: because if he said he was in grad school, it'd
38:58
Speaker 1: be like, what are we that old?
38:59
Speaker 2: We're not old enough to have earned a PhD. Almost
39:01
Speaker 2: though everybody's been listening that long has a PhD in
39:04
Speaker 2: Internet physics.
39:05
Speaker 1: Yeah, or we others people who get their PhDs in
39:07
Speaker 1: like two or three years. It's totally possible, right, Yeah, absolutely,
39:11
Speaker 1: that's true. I hope we've been out there guiding some
39:13
Speaker 1: folks through their PhDs. All right, Well, Ryan's question is
39:16
Speaker 1: kind of an interesting one, but kind of a philosophical
39:18
Speaker 1: or a subtle one. I think he wants to know, like,
39:21
Speaker 1: why are you trying to unify the four forces of nature?
39:24
Speaker 1: Or why are you trying to unify classical mechanics or
39:27
Speaker 1: like general relativity with quantum mechanics. Can you just let
39:31
Speaker 1: them be their own thing? And maybe we're in a
39:33
Speaker 1: universe where they don't have to be unified, or they
39:36
Speaker 1: don't want to be unified, or you know, we should
39:38
Speaker 1: just think of them as separate things. I think that's
39:40
Speaker 1: his question, right. I think you're right, And I love
39:42
Speaker 1: the audacity of this question. You're like, aren't all y'all
39:45
Speaker 1: wasting your time? What's the whole point of.
39:48
Speaker 2: This big project of physics to try to explain the
39:50
Speaker 2: whole universe?
39:52
Speaker 1: Well? I don't know if you said that, but it
39:54
Speaker 1: does sound like you're sensitive about that.
39:56
Speaker 3: No.
39:56
Speaker 2: I love that because it takes sometimes young people showing
39:59
Speaker 2: up up and looking at what us senior folks have
40:02
Speaker 2: done and scratching their heads and going is this the
40:04
Speaker 2: right direction? Or did you guys make a basic wrong
40:07
Speaker 2: assumption like on step one. That's how we can make
40:10
Speaker 2: really great progress because some of us are sort of
40:12
Speaker 2: stuck in certain ways of thinking. So I love these
40:15
Speaker 2: sort of basic naive questions about the whole project of science.
40:18
Speaker 1: Cool. Well, his question is why bother, Daniel, why are
40:21
Speaker 1: you trying to find a theory of everything? Couldn't we
40:24
Speaker 1: just have a four nice theories of everything and be
40:27
Speaker 1: happy with that? Or maybe that's just how the universe is,
40:29
Speaker 1: that it has four separate rules that it's stuck too.
40:34
Speaker 2: Well, he's right to question, because philosophically, the universe doesn't
40:38
Speaker 2: necessarily have to have a single theory of everything. I mean,
40:42
Speaker 2: that would be pretty weird to have like several different
40:45
Speaker 2: theories that seem to be based on different principles and
40:47
Speaker 2: operate under different rules. But we don't have any guarantee
40:51
Speaker 2: that the universe has a single theory of everything. We
40:53
Speaker 2: recently had a philosopher on the podcast to talk about
40:56
Speaker 2: this exact topic and philosophy, it's called disunity, the idea
41:00
Speaker 2: that you can't combine all the theories of physics into one,
41:03
Speaker 2: that there might be just like different regimes in different
41:05
Speaker 2: realms where different laws apply. That would be weird, though,
41:09
Speaker 2: because you've got to ask, like what happens in between,
41:12
Speaker 2: you know, the boundaries between the two laws or where
41:15
Speaker 2: they kind of overlap. That's where the questions are. But
41:18
Speaker 2: you know, we don't know for sure. Nobody's promised us
41:21
Speaker 2: that physics can be boiled down to a T shirt.
41:23
Speaker 1: Sounds like the answer to Ryan's question then, is that
41:27
Speaker 1: we don't need to unify classical mechanics and quantum mechanics.
41:30
Speaker 1: You're just doing it to be annoying, to be that
41:32
Speaker 1: annoying kid who keeps asking why why do they need
41:34
Speaker 1: to be unified? Why not? I'm still getting paid.
41:37
Speaker 2: We're not just doing it to be annoying. We're doing
41:39
Speaker 2: it for a few pretty good reasons. One is that philosophically,
41:43
Speaker 2: it makes a lot more sense to have a single
41:45
Speaker 2: theory of the universe. I mean, something is happening out
41:48
Speaker 2: there in the universe, and we imagine that that something
41:51
Speaker 2: is following some rules, and those rules should be like
41:54
Speaker 2: self consistent. And if you have multiple rules, then you
41:57
Speaker 2: got to sometimes wonder, like, well, which rule applies? You know,
42:00
Speaker 2: It's like if mom and dad have different rules a
42:02
Speaker 2: boy dessert and then they're both home for dinner. Like
42:05
Speaker 2: whose rule applies? Do you get ice cream after dinner
42:07
Speaker 2: or not? You know, the universe has to make decisions, right,
42:10
Speaker 2: things have to happen or not happen, and so there's
42:13
Speaker 2: no room for things to clash. That's sort of philosophical answer.
42:18
Speaker 1: Is that necessarily true? Though, canny? You have two fundamental
42:21
Speaker 1: rules about the universe that don't clash, Like, you know,
42:24
Speaker 1: Dad can say you can't have dessert on Monday, Wednesday,
42:26
Speaker 1: and Friday, but mom says you can't have dessert Tuesday,
42:29
Speaker 1: Thursday and on weekends, and that kind of works out. No,
42:33
Speaker 1: it actually doesn't work out for the kid because then
42:35
Speaker 1: they can't have dessert.
42:36
Speaker 2: If you had rules that were exclusive, that had separate
42:38
Speaker 2: regimes that never conflicted, then sure. And the fascinating thing
42:42
Speaker 2: is that that's almost true for Ryan's suggestion about classical
42:46
Speaker 2: mechanics and quantum mechanics, Like classical mechanics and general relativity
42:50
Speaker 2: specifically mostly deals with really really big stuff. Gravity is
42:55
Speaker 2: so weak that basically it's only relevant for things like
42:58
Speaker 2: bigger than a baseball or or a planet or a galaxy.
43:02
Speaker 2: And quantum mechanics mostly applies to the very very small stuff, right.
43:05
Speaker 2: Its effects basically wash out or average out for anything
43:08
Speaker 2: that's big enough for gravity to play a role. That's
43:10
Speaker 2: one reason why it's been hard to unify them because
43:13
Speaker 2: they rarely talk about the same thing. They're mostly non overlapping,
43:17
Speaker 2: except of course, where it gets really interesting. Inside a
43:21
Speaker 2: black hole, for example, things are super duper small, so
43:23
Speaker 2: quantum mechanics is important, and super duper massive, so gravity
43:28
Speaker 2: is important. So what happens inside a black hole? Right?
43:31
Speaker 2: What happens when mom and dad disagree about the dessert
43:34
Speaker 2: you're going to get. In the case of quantum mechanics
43:36
Speaker 2: and general relativity, they're not completely exclusive. They do have
43:40
Speaker 2: to agree on what happens inside a black hole.
43:42
Speaker 1: Yeah, they do have to agree, but we don't know
43:44
Speaker 1: that they disagree, right, Like, we just don't know what
43:46
Speaker 1: happens inside of a black hole. I think you said
43:48
Speaker 1: earlier that you can have quantum mechanics on curve space,
43:52
Speaker 1: and so maybe what if gravity's used to think the
43:54
Speaker 1: curve space and quantum mechanics just sits on top of that,
43:57
Speaker 1: and maybe inside of a black hole they find a
43:59
Speaker 1: way to agree about who eats deserved on Sundays.
44:03
Speaker 2: But if they agree, then you're unifying them, right, You're
44:06
Speaker 2: bringing them together to make the same prediction. You're showing
44:09
Speaker 2: that they're fundamentally the same theory. They make the same
44:12
Speaker 2: prediction inside a black hole.
44:14
Speaker 1: Or I guess not that they maybe not that they agree,
44:16
Speaker 1: but that they don't disagree.
44:18
Speaker 2: I guess, yeah, well, right now they do disagree, right.
44:20
Speaker 2: General relativity predicts singularities and quantum mechanics says nuh uh no,
44:24
Speaker 2: deserve for you. So they definitely disagree right now, which
44:28
Speaker 2: means we need to modify one of them to make
44:30
Speaker 2: them agree.
44:31
Speaker 1: Do they disagree? I wonder? I mean, like, you know,
44:35
Speaker 1: general relativity says that a singularity is possible, right, but
44:39
Speaker 1: what if it's just not possible because quantum mechanics doesn't
44:43
Speaker 1: allow particles to have singularities.
44:45
Speaker 2: Yeah, that's one solution is to just carve out that
44:48
Speaker 2: region and say general relativity doesn't apply here. The rules
44:52
Speaker 2: of generalativity apply outside of ent horizons and not inside
44:55
Speaker 2: of horizons. It creates event horizons, but then inside of
44:58
Speaker 2: it it doesn't work, and in fact, the of general
45:00
Speaker 2: relativity are kind of nonsense. Inside of event horizon, a
45:03
Speaker 2: singularity we don't think is a physical prediction, and so
45:06
Speaker 2: you could just carve out general relativity and say outside
45:08
Speaker 2: this dotted line, it applies. Inside that dotted line it doesn't,
45:11
Speaker 2: and quantum mechanics rules there. I think that's less satisfying
45:14
Speaker 2: than finding a way to unify them, but it might
45:16
Speaker 2: be the way the universe works. We do not have
45:19
Speaker 2: a guarantee that everything is unified into a complete, single theory.
45:22
Speaker 2: On the other hand, we have a lot of historical
45:26
Speaker 2: trends in that direction, like unity seems to be the
45:30
Speaker 2: rule of the universe. We've had a lot of success
45:32
Speaker 2: finding ways to click together other phenomena to simplifier explanations
45:36
Speaker 2: of the universe down from more forces to fewer forces.
45:40
Speaker 1: Right, Like you mentioned earlier, electricity and magnetism were combining
45:44
Speaker 1: to electromagnetism and electromagtism, and the week four we're combining
45:48
Speaker 1: to electroweak force. Could you merge electroweak force with the
45:51
Speaker 1: strong force to get the electromediocre force.
45:56
Speaker 2: It is a really fun question about what would happen
45:58
Speaker 2: to the names there, because you notice that when electromagnetism
46:02
Speaker 2: and the weak force got merged, magnetism got dropped It's
46:05
Speaker 2: like that middle partner that when the law firms merge,
46:07
Speaker 2: it just got removed from the name, right, it's just
46:10
Speaker 2: electro week. And so when we merge electroweek with a
46:13
Speaker 2: strong force, what's going to get dropped? I don't know
46:15
Speaker 2: if it becomes electro strong or something else. But anyway,
46:19
Speaker 2: we haven't been able to do that yet. Those are
46:21
Speaker 2: called grand unified theories. They exclude gravity. Just adding the
46:25
Speaker 2: strong force together with electricweek would be a grand unified theory,
46:29
Speaker 2: and we haven't able to do that. But we do
46:30
Speaker 2: have some interesting hints. If we think about what happens
46:33
Speaker 2: at very very high energies, there's this fascinating clue that
46:37
Speaker 2: suggests that we might be able to unify the forces.
46:40
Speaker 1: But I guess Ryan's question is more like, why do
46:43
Speaker 1: they have to be unified? Like couldn't I mean, you're
46:45
Speaker 1: calling them already fundamental forces. Why can't we just live
46:48
Speaker 1: in a universe where there's the electroweak force and the
46:51
Speaker 1: strong force at the same time. Those two don't conflict,
46:53
Speaker 1: do they?
46:54
Speaker 2: Those two do non conflict, And yeah, we could, I
46:56
Speaker 2: think just esthetically, we prefer simpler explanations, right, That's the
47:00
Speaker 2: reason we started this project. That's the reason we discovered
47:03
Speaker 2: that electricity and magnetism were actually just one thing, not
47:07
Speaker 2: two separate things, because we were looking for unity for simplicity.
47:11
Speaker 2: So I think it's just philosophical. We prefer those kinds
47:14
Speaker 2: of explanations, so we search for them. We hope to
47:17
Speaker 2: find a simple explanation for the universe, but we're not
47:19
Speaker 2: guaranteed that it will be simple or that it will
47:21
Speaker 2: be unified. It just has to be self consistent, and
47:24
Speaker 2: it either comes by unifying them or by drawing dotted
47:27
Speaker 2: lines and saying, y'all have to play in different sandboxes.
47:29
Speaker 1: And I guess to answer Ryan's question, like, philosophically, we
47:32
Speaker 1: could just leave it at that, right, Like we could
47:34
Speaker 1: just say, well, the electroweak force is separate than the
47:37
Speaker 1: strong force. There just two different things doing their own things.
47:41
Speaker 1: We could just leave it at that, right, But then
47:43
Speaker 1: all of your physicists would have nothing to do.
47:45
Speaker 2: Kind of Yeah, we could stop asking questions and stop
47:48
Speaker 2: being curious and stop looking for patterns and simplicity. But
47:51
Speaker 2: it's gotten us pretty far so far, so I think
47:53
Speaker 2: it's a worthwhile effort. I'm going to keep looking for
47:56
Speaker 2: patterns and looking for ways to click these puzzle pieces
47:59
Speaker 2: together in two simpler ideas that explain the universe. And
48:03
Speaker 2: again we do have some really tantalizing hints. You know,
48:05
Speaker 2: as you crank up the energy of all these things,
48:08
Speaker 2: the strength of the forces change, right, the force of
48:11
Speaker 2: the weak force and the electromagnetism and the strong force.
48:14
Speaker 2: The power these forces changes with the energy you use
48:17
Speaker 2: in the interaction, and it seems like as you crank
48:20
Speaker 2: up the energy, those strengths sort of converge, like the
48:23
Speaker 2: strong force gets weaker and the other forces get stronger,
48:25
Speaker 2: and they seem to be sort of growing towards a
48:27
Speaker 2: single value, which suggests that maybe they actually are a
48:31
Speaker 2: part of the same force, but we haven't figured that
48:34
Speaker 2: out yet.
48:35
Speaker 1: It sounds to me like maybe the real answer to
48:37
Speaker 1: Ryan's question is why are we trying to unify the forces.
48:40
Speaker 1: The answer is because we don't know that they're not unified, right.
48:43
Speaker 2: That's right, and we have lots of examples of successfully
48:45
Speaker 2: unifying them in the past, so let's keep.
48:48
Speaker 1: Going, right. It's like you're trying to basically find the answer,
48:52
Speaker 1: positive or negative, whether or not they can be unified,
48:54
Speaker 1: because that's kind of what science does, is you come
48:56
Speaker 1: up with a question and you can have to answer
48:58
Speaker 1: it right, even if it annoys the universe.
49:01
Speaker 2: Or even if the answer annoys us. If we discover
49:03
Speaker 2: that the explanation for everything requires like a bunch of
49:06
Speaker 2: different ideas with dotted lines drawn between them, that won't
49:10
Speaker 2: be so satisfying. But hey, it will be the.
49:12
Speaker 1: Truth at least until the sequel game comes out, now
49:16
Speaker 1: with more forces, now with the ability to save your progress.
49:20
Speaker 1: All right, well, thank you to all of our listeners
49:22
Speaker 1: for sending in their question, and especially thanks to the
49:25
Speaker 1: three whose question we answered here today. Thanks for your curiosity.
49:28
Speaker 2: Thank you everybody, and please don't be shy. If you
49:31
Speaker 2: have a question about how the universe works, or doesn't
49:33
Speaker 2: work or shouldn't work, please write to us to questions
49:37
Speaker 2: at Danielandjorge dot com.
49:39
Speaker 1: We hope you enjoyed that. See you next time.
49:49
Speaker 2: Thanks for listening, and remember that Daniel and Jorge Explain
49:52
Speaker 2: the Universe is a production of iHeartRadio. For more podcasts
49:56
Speaker 2: from iHeartRadio, visit the iHeartRadio app, Apple podcast, or wherever
50:01
Speaker 2: you listen to your favorite shows.