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Speaker 1: Hey, Daniel, does being a scientists require a lot of travel?

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Speaker 2: Yeah, you know, conferences and meetings and all that kind

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Speaker 2: of stuff.

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Speaker 1: But that's just talking about science. What about actually doing science?

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Speaker 1: And you need to go somewhere into the lab or

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Speaker 1: out into the field.

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Speaker 2: Yeah, you got to do that. Also, I'm pretty lucky

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Speaker 2: that the collider I work out is in a pretty

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Speaker 2: beautiful spot in Switzerland.

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Speaker 1: But do you actually have to go there, like you

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Speaker 1: have to press buttons or fix the machine?

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Speaker 2: Who else is going to hit that big red button

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Speaker 2: in the control room if not me? Man?

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Speaker 1: Or did you just go? Are of talk?

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Speaker 2: There's definitely a lot of talking and coffee drinking, But yeah,

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Speaker 2: somebody has to actually build a thing and make it run.

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Speaker 2: So people got to be there in person.

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Speaker 1: And I guess you got to talk to them, right,

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Speaker 1: I'm just wondering, an why do you actually have to

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Speaker 1: go to Switzerland?

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Speaker 2: Yeah, some of us have to actually go to build

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Speaker 2: a thing. We built part of the detector and the

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Speaker 2: readout systems that gather the data. We're responsible for making

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Speaker 2: it work, and you got to be there when it breaks.

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Speaker 1: M Now, is that the best physics location to get

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Speaker 1: stationed at?

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Speaker 2: I think it's one of the top ones. It's definitely

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Speaker 2: better than the suburbs of Chicago, where we worked more recently.

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Speaker 1: Hey, what's wrong with Chicago?

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Speaker 2: Chicago's awesome. The suburbs a little bit less exciting. But

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Speaker 2: there's an experiment on the Mediterranean. So those people basically

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Speaker 2: work on the French Riviera.

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Speaker 1: Nice. Do they work in speedos and swimsuits or not?

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Speaker 1: Since it's the French Priviera.

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Speaker 2: I don't think you want to visualize physicists and speedos.

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Speaker 1: Yeah, let's not do that.

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Speaker 2: On the other extreme, our experiments at the South Pole.

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Speaker 1: Ooh, that sounds super cool.

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Speaker 2: It's a little too cool for my tastes.

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Speaker 1: That sounds awesome, somewhere I want to go at least

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Speaker 1: once in my life. Hi am Jeha May, cartoonist and

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Speaker 1: the author of Oliver's Great Big Universe.

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Speaker 3: Hi.

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Speaker 2: I'm Daniel. I'm a particle physicist and a professor at

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Speaker 2: uc Ervine, and I'd be happy to die without ever

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Speaker 2: going to the South Pole.

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Speaker 1: Well, I guess you don't want to go to the

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Speaker 1: South Pool to die or have those two coin side.

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Speaker 1: But if you had the opportunity, when did you want

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Speaker 1: to go?

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Speaker 2: I actually have had the opportunity, but I said no

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Speaker 2: thank you.

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Speaker 1: You said no thank you.

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Speaker 2: I've said no thank you. Why the South Pole seems

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Speaker 2: kind of cold and uncomfortable. I'm not that into unpleasant travel,

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Speaker 2: same reason I don't really want to go to space.

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Speaker 1: Yeah, well I think space is a little bit colder

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Speaker 1: than the South Pole. Yeah, don't you want to go

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Speaker 1: for the adventure? See some penguins, some live penguins, not

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Speaker 1: in a zoo.

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Speaker 2: I think when I was younger, I was more into

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Speaker 2: adventure travel than I am now.

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Speaker 1: Now you're more into couch adventures.

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Speaker 2: I'm less into discomfort now than I used to be.

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Speaker 1: But anyways, welcome to our podcast, Daniel and Jorge Explain

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Speaker 1: the Universe, a production of our Heart Radio.

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Speaker 2: A mentally adventure, a way to travel the entire universe

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Speaker 2: and think about everything that's happening out there, how things

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Speaker 2: work at the tiny particle level, how things work at

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Speaker 2: the galactic scale, and everything in between. Physics is our

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Speaker 2: way of exploring this vast universe and trying to make

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Speaker 2: sense of it, and our job on the podcast is

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Speaker 2: to help you make sense of it as well.

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Speaker 1: That's right. We live in an amazing cosmos and we

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Speaker 1: are just tourists making our way through it, observing all

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Speaker 1: the sites and learning all of the languages that it has,

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Speaker 1: and eating all the foods it has to offer.

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Speaker 2: We're not tourists to this cosmos. We live here, man,

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Speaker 2: We are home here. We're just trying to understand our

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Speaker 2: own context. It's not like we came here from some

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Speaker 2: other part of the multiverse to poke in prad and

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Speaker 2: take pictures.

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Speaker 1: Well, we're tourists in the sense that we're early here

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Speaker 1: for a very short amount of time.

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Speaker 2: And we hope that in that time we can help

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Speaker 2: unravel some of the deep questions of the nature of

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Speaker 2: the universe.

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Speaker 1: Yes, because there are a lot of amazing things out

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Speaker 1: there for us to ask questions about and to explore

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Speaker 1: and to wonder why they exist.

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Speaker 2: Unfortunately, we can't mostly go out there to explore the universe.

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Speaker 2: We have to just see what comes to us here

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Speaker 2: on Earth. In this tiny little corner of the universe.

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Speaker 2: We can actually gather an incredible amount of information based

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Speaker 2: on all the particles that do arrive here on Earth,

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Speaker 2: the photons, the neutrinos, and sometimes the odd ball particles.

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Speaker 1: Wait, we can't just put physicists in a spaceship and

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Speaker 1: send them out to other planets.

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Speaker 2: If you want to fund that, I bet you'll have

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Speaker 2: lots of volunteer physicists. Just not me.

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Speaker 1: What if they have nice chocolates like they do in Switzerland.

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Speaker 2: I don't think chocolate is enough to counterbalance the discomfort, because,

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Speaker 2: after all, you can still get pretty nice chocolates without

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Speaker 2: getting in the spaceship.

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Speaker 1: How do you know, maybe they taste better in space.

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Speaker 2: We'll let someone else do that experiment and report back.

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Speaker 1: It would be chocolates that are out as this world.

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Speaker 2: Cosmic chocolates. Well, we can do lots of cool experiments

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Speaker 2: just here on Earth, and not just building telescopes to

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Speaker 2: capture photons or neutrinos. Sometimes we can actually use the

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Speaker 2: Earth itself to see these particles.

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Speaker 1: Yeah, the Earth is a big place and it catches

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Speaker 1: a lot of stuff from space, from other parts of

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Speaker 1: the galaxy, from other parts of the universe, and we

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Speaker 1: can use it to try to catch things that maybe

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Speaker 1: we haven't seen before.

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Speaker 2: Some of the telescopes that we build actually rely on

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Speaker 2: the Earth being there to induce the particles to interact

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Speaker 2: to reveal themselves without the Earth. Some of these particle

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Speaker 2: telescopes wouldn't even work.

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Speaker 1: So today on the podcast, we'll be asking the question

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Speaker 1: how can we look for magnetic monopoles?

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Speaker 2: Now?

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Speaker 1: Is this related to monopoly the game or the capitalism concept?

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Speaker 2: I think it's somewhat related to capitalism. Yeah, having just

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Speaker 2: like one source of chocolate, somebody has a monopoly on chocolate.

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Speaker 2: Monopoles are also like a source of charge.

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Speaker 1: Okay, it's a bit of a stretch. What are physicists

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Speaker 1: in this stretched analogy? Here are you the boot? Are

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Speaker 1: you the little car? Are you the top hat?

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Speaker 2: We are buying it up. We are trying to purchase

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Speaker 2: knowledge about the universe.

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Speaker 1: Hopefully you don't land and go to jail, do not

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Speaker 1: pass go.

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Speaker 2: I will happily go to physics jail if that's what's

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Speaker 2: required to unravel the mysteries of the universe.

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Speaker 1: I guess researches are a little bit like drawing chance cards.

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Speaker 2: Oh, it definitely is. I've had so many conversations with

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Speaker 2: students where they've been like, I've been working for sixty

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Speaker 2: hours a week for a year and haven't gotten anywhere.

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Speaker 2: I'm like, number one, don't work sixty hours a week.

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Speaker 2: Number two, there's no guarantee that time spent means progress made.

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Speaker 2: There's so much randomness in research.

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Speaker 1: And number three, you should be working eighty hours a week.

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Speaker 2: No, you should definitely not be working eighty hours a week.

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Speaker 2: You got to take care of your people's mental health. Man.

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Speaker 1: But yeah, I guess it's not maybe related to the

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Speaker 1: board game. I'm guessing it's maybe related to magnetism and

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Speaker 1: magnetic polls exactly.

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Speaker 2: It has to do with deep questions about where charge

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Speaker 2: comes from in electricity, where magnetism comes from in magnetism,

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Speaker 2: how the two are connected, why we have quantized amounts

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Speaker 2: of electric charge in this universe, and why we have

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Speaker 2: quantized amounts of electric charge in this universe. It's sort

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Speaker 2: of like a big open question in particle physics.

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Speaker 1: Yeah, we're gonna jump into what a magnetic monopole is,

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Speaker 1: but first we were wondering how many people out there

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Speaker 1: had heard of this concept and thought about the idea

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Speaker 1: of how to look for them.

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Speaker 2: So thanks very much to everybody who answers these questions.

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Speaker 2: If you would like to hear your voice on the

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Speaker 2: podcast answering the Question of the Day, please write to

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Speaker 2: me two questions at Danielandjorge dot com.

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Speaker 1: We think about it for a second. How do you

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Speaker 1: think we can look for magnetic monopoles? What people had

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Speaker 1: to say, I have no idea what that means. But

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Speaker 1: maybe yeah, if it was a monopole, it messed with

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Speaker 1: other magnetic fields, and so we could look for disturbances

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Speaker 1: and die poles.

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Speaker 3: First of all, I would ask who it really exists.

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Speaker 2: I know you have a podcast on that, but I

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Speaker 2: haven't listened to it yet. I actually don't know.

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Speaker 3: I really don't know. Looking forward to hear from it

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Speaker 3: from you, I.

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Speaker 1: Would say by closing one eye.

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Speaker 4: But I think they may not this because the needs

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Speaker 4: to rebalance the nature, and this just seems unbalanced.

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Speaker 5: Where are monocles?

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Speaker 4: I don't know what a monopole is, so I don't know.

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Speaker 4: Maybe something related to like the magnetic field of Earth,

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Speaker 4: just for the universe, Like maybe the universe has a

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Speaker 4: joint magnetic field. I don't know. I can't wait to

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Speaker 4: search it up.

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Speaker 5: I'm not sure how we could look for magnetic monopoles.

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Speaker 5: If they're large, then maybe we could look at how

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Speaker 5: things act around them out in space. But if they're

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Speaker 5: really small, I have no idea.

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Speaker 3: I wouldn't even know where to look, never mind how

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Speaker 3: to look. I believe classical electromagnetism doesn't allow for magnetic monopoles,

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Speaker 3: but maybe there is some kind of quantum weirdness that

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Speaker 3: at least theoretically predicts them. But I don't have a

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Speaker 3: clue about how to find.

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Speaker 1: All right, we got to tell comedians here in the batch.

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Speaker 1: Somebody say, maybe we can look for monopoles by wearing monocles.

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Speaker 2: The guy in Monopoly wears a monocole, after all, doesn't he?

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Speaker 1: Oh, yes, it's all there. It was a hidden sign.

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Speaker 2: You don't have a monopoly on jokes and physics.

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Speaker 1: Apparently apparently not, because two people have brought up this joke.

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Speaker 1: Somebody said you can also look for them by closing

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Speaker 1: one eye. But which I I guess that's the question.

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Speaker 1: Maybe you have to roll the die.

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Speaker 2: Depends if it's a left or right handed monopole.

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Speaker 1: I suppose monopoles are handed. There's handedness and magnetism.

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Speaker 2: If it has spin, then it's going to have handedness absolutely.

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Speaker 1: M All right, well let's dig into this concept. Maybe

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Speaker 1: a lot of people haven't heard what a monopole is.

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Speaker 1: A magnetic monopole is, so Daniel explained to us what

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Speaker 1: is a magnetic monopole.

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Speaker 2: A magnetic monopole is easiest to understand if you first

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Speaker 2: get your mind around what an electric monopole is. If

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Speaker 2: you could understand what a monopole is in electricity, then

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Speaker 2: we can understand what it is in magnetism. And in electricity.

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Speaker 2: A monopole is pretty simple. It's just something that has

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Speaker 2: an o overall charge, like an electron. Electron has negative charge.

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Speaker 2: It's a source of charge, and the proton has a

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Speaker 2: positive charge. It's a source of charge. You add up

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Speaker 2: all the charge on the object. It's either positive or

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Speaker 2: it's negative. It's not zero, and that creates a particular

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Speaker 2: kind of field. Gases law for electricity tells you, for example,

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Speaker 2: that the electric field through a surface depends on the

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Speaker 2: total amount of charge in the volume. So a monopole

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Speaker 2: and electricity is just something that has an overall charge

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Speaker 2: to it.

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Speaker 1: So, as you said, like an electron is maybe the

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Speaker 1: ultimate negative electric monopole, right, Like it's just the point particle.

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Speaker 1: It's just a little point in space that has a

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Speaker 1: negative charge to it, and it looks negative from all

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Speaker 1: directions exactly.

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Speaker 2: And the atom is the combination of the proton and

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Speaker 2: the electron. It's overall neutral. It has no overall charge,

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Speaker 2: so it's not a monopole, but it is a dipole

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Speaker 2: because the positive charge and the negative charge are not

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Speaker 2: exactly on top of each other. They don't totally cancel out,

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Speaker 2: so if you're closer to one than the other, you'll

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Speaker 2: still feel an electric field. But that's a dipole field.

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Speaker 2: It's a field that comes from something that has a

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Speaker 2: positive and a negative charge. Right, Dipole means two, so

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Speaker 2: it comes from something where the charge is overall zero,

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Speaker 2: but it has a distribution. So monopolsm that has an

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Speaker 2: overall charge, like the electron of the proton. A dipole

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Speaker 2: has no overall charge, but the distribution of charge inside

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Speaker 2: that neutral object still gives you an electric field, a

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Speaker 2: dipole field.

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Speaker 1: I think what you mean is like the nucleus of

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Speaker 1: an atom is neutral because there are or at least

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Speaker 1: it's positive, right, because it has protons and neutrons in it,

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Speaker 1: And then the outer part of the atom has the electron,

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Speaker 1: which is negative, and the electron is going around the nucleus,

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Speaker 1: so at any given time there's one side of the

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Speaker 1: atom that's more negative than the other side, right, But

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Speaker 1: it's sort of like it's electron is flying around, right,

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Speaker 1: So it's changing for an atom all the time, exactly.

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Speaker 2: And if you're really far away from the atom, then

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Speaker 2: the distance between the electron and the proton doesn't really matter.

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Speaker 2: You can think of them as on top of each other,

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Speaker 2: and the dipole field goes to zero very quickly. But

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Speaker 2: as you get close to it, then that does matter,

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Speaker 2: and so there is an electric field that doesn't cancel out. Right,

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Speaker 2: The electric field of the electron and the proton don't

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Speaker 2: cancel out, so you feel a dipole field.

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Speaker 1: Meaning like if you're really close to the atom, super

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Speaker 1: duper close to the and you're like an electron, for example,

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Speaker 1: you might be pushed in one direction more than the other.

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Speaker 2: Yeah, exactly. You can imagine a field from the electron

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Speaker 2: and a field from the proton. If you're really far away,

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Speaker 2: then they're basically canceling each other out. But if you're

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Speaker 2: really close to the two of them, you're going to

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Speaker 2: be closer to one than the other by a big

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Speaker 2: fraction and they're not going to cancel out. So that's

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Speaker 2: a dipole field.

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Speaker 1: So monopoles do exist, like an electron is a monopole,

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Speaker 1: isn't it.

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Speaker 2: Yes, an electric monopole does exist. You can have a

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Speaker 2: piece of matter with an overall charge to it that

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Speaker 2: creates this monopole field, right, just a very simple field.

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Speaker 2: And dipole fields exist in electricity, in quadrupole fields and

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Speaker 2: octopole fields. Actually, it's part of this multipole expansion. If

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Speaker 2: you like to think about vector spaces and linear algebra,

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Speaker 2: you can break any yield and the expansion of these

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Speaker 2: different poles. The first term is the monopole, then the dipole,

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Speaker 2: then the quadrupole, et cetera, et cetera. But conceptually you

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Speaker 2: can think about the monopole is coming from something that

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Speaker 2: has an overall charge.

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Speaker 1: All right, so that's an electric monopole. I'm guessing maybe

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Speaker 1: a magnetic monopole is different.

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Speaker 2: A magnetic monopole is the exact analog, except use magnetic

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Speaker 2: charge instead of electric charge.

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Speaker 1: Wait wait, wait, wait wait, what's the difference between magnetic

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Speaker 1: charge and electric charge?

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Speaker 3: All right?

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Speaker 1: I thought that was the same thing.

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Speaker 2: Well, they're very tightly connected because we've unified electricity and

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Speaker 2: magnetism into one overall force called electromagnetism. Right, But there

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Speaker 2: are two different parts of it. There's electricity and there's magnetism.

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Speaker 2: There are different components of electromagnetism.

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Speaker 1: Like what's the difference, Like, if two electrons are repelled

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Speaker 1: from each other, aren't they pushing away from each other

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Speaker 1: using the electromagnetic force?

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Speaker 2: Yes, absolutely they are, and there's components to that which

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Speaker 2: are electric, like this the Colombic repulsion just from the

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Speaker 2: electric charges. But if they're in motion, then one of

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Speaker 2: them can be generating a magnetic field, and that magnetic

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Speaker 2: field and also turn the other electron for example, So

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Speaker 2: there's both electric and magnetic components to how two electrons interact.

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Speaker 1: Hmmm, So I guess you would maybe have to dig

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Speaker 1: into the equations, But is there a way to sort

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Speaker 1: of explain the difference between magnetism and electricity, Like.

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Speaker 2: Magnetism has a different set of charges. We call them

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Speaker 2: north and south, right, So you can have a magnet

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Speaker 2: that has a north and a south and you know

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Speaker 2: that if you bring the north end close to another

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Speaker 2: north end, it repels two north's repel and two south repels.

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Speaker 2: So these are the magnetic charges, the north and the

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Speaker 2: south charges.

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Speaker 1: But aren't those like emergent properties, Like aren't the all

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Speaker 1: just made out of electrons, which are monopoles.

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Speaker 2: Yes, exactly, All the magnetic fields in the universe are dipoles.

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Speaker 2: All of magnetism is generated by electric monopoles, either moving

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Speaker 2: charges or quantum spin. So all the magnetic fields we

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Speaker 2: have in the universe are generated by electric monopoles. If

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Speaker 2: there are magnetic monopoles, then those would also generate pure

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Speaker 2: magnetic fields, like a pure north field or pure south field,

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Speaker 2: not a dipole field where you have like a north

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Speaker 2: on one end and a south on the other. If

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Speaker 2: you have a bar magnet, for example, it has a

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Speaker 2: north on one side and a south on the other.

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Speaker 2: You try to crack it in half, You're not going

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Speaker 2: to get a pure north on one side and a

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Speaker 2: pure south on the other. You're going to end up

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Speaker 2: with two bar magnets, each of which is a dipole

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Speaker 2: with a north and a south. As far as we know,

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Speaker 2: there are no pure magnetic charges out there, no like

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Speaker 2: particles that just have a north or particles that just

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Speaker 2: have a south. That would be a magnetic monopole, the

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Speaker 2: equivalent of like an electron, which is an electric monopole.

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Speaker 1: Okay, so I guess I'm still trying to wrap my

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Speaker 1: head around this difference, because I always thought it was

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Speaker 1: maybe the same thing. So you're saying, like, if I

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Speaker 1: have an electron and I spin it, it's going to

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Speaker 1: create a dipole.

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Speaker 2: It's going to create a magnetic dipole. Right, It's going

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Speaker 2: to have a north and a south. So electrons have

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Speaker 2: quantum spin. They don't literally spin in the way that

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Speaker 2: like a top spins, but their quantum spin does generate

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Speaker 2: a little magnetic field. But that magnetic field has a

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Speaker 2: north and a south. It's not just a north or

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Speaker 2: not just a south.

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Speaker 1: Right. But I guess the question is, like, what is

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Speaker 1: a magnetic field.

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Speaker 2: A magnetic field is something that's generated either by a

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Speaker 2: magnetic monopole or induced by an electric current, right, And

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Speaker 2: electric currents can only induce magnetic dipoles. They can't induce

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Speaker 2: magnetic monopoles.

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Speaker 1: I guess what I mean is like to the labors,

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Speaker 1: and how would you define a magnetic.

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Speaker 2: Field in the same way that you think about electric fields.

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Speaker 2: These are sort of theoretical concepts that explain how two

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Speaker 2: particles push on each other. So how does an electron

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Speaker 2: push on another electron? We say it's using the electric field.

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Speaker 2: Really that's just our way of saying, this is what

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Speaker 2: two electrons do to each other. Magnetic fields are similar,

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Speaker 2: the two are very closely paired. Electric fields and magnetic

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Speaker 2: fields very tightly coupled. But a magnetic field is different

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Speaker 2: from an electric field, right, It does different things. It's

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Speaker 2: generated in different ways. It applies different forces to charges,

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Speaker 2: or a magnetic field does different things to magnetic charges

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Speaker 2: than it does to electric charges. All these things are

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Speaker 2: described by Maxwell's equations, but in the end it's just descriptive, right,

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Speaker 2: Like we see these things happening to electrons and to

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Speaker 2: bar magnets and to other particles in the universe, we

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Speaker 2: try to boil them down into as compact the description

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Speaker 2: as possible, and then we come up with this story

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Speaker 2: that we tell ourselves about what's happening, and that story

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Speaker 2: includes fields. Are those fields real and physical things that

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Speaker 2: are out there in the universe. We can't like see

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Speaker 2: them directly, We only see their impact on other particles.

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Speaker 2: So when you ask me, like, well, what is a field, Well,

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Speaker 2: it's sort of a theoretical philosophical construct that explains the

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Speaker 2: motions of the particles that we see. They seem to

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Speaker 2: follow certain rules and those are best explained by these

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Speaker 2: fields that we've built up in our minds.

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Speaker 1: I guess maybe I think what you're saying is that

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Speaker 1: a field is sort of like an idea that tells you, like,

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Speaker 1: if I put an electron in here relative to this

385
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Speaker 1: other electron, it's going to field a repulsive electric force

386
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Speaker 1: in that direction. Or if I put it over here

387
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Speaker 1: and this other location is going to feel the force

388
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Speaker 1: in a different direction by a different amount. And so

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Speaker 1: maybe a magnetic field is sort of the same, Like

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Speaker 1: if I have a magnetic field and I throw an

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Speaker 1: electron add it, it's going to do different things depending

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Speaker 1: on whether it's you know, flying close to the north

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Speaker 1: side of this magnetic field, or it's the south side.

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Speaker 2: Right, Yeah, that's right. These fields were invented as a

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Speaker 2: concept to explain action at a distance, like how did

396
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Speaker 2: two electrons push on each other if they're not actually touching,

397
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Speaker 2: And so you create this field concept. Say an electron

398
00:18:17,000 --> 00:18:19,720
Speaker 2: creates a field through space, and that field can push

399
00:18:19,760 --> 00:18:24,240
Speaker 2: on the other electronic transfers momentum to the other electron. So, yeah,

400
00:18:24,320 --> 00:18:26,879
Speaker 2: magnetic fields have different rules, and these are all described

401
00:18:26,880 --> 00:18:30,040
Speaker 2: by Maxwell's equations. You throw an electron through a magnetic field,

402
00:18:30,280 --> 00:18:32,480
Speaker 2: it's going to curve. You throw an electron through an

403
00:18:32,560 --> 00:18:35,480
Speaker 2: electric field, it will get accelerated in some direction to

404
00:18:35,640 --> 00:18:36,760
Speaker 2: the rules are a little.

405
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Speaker 1: Bit different, So I guess the way the universe works,

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Speaker 1: it's just kind of weird thing. Like if you take

407
00:18:41,200 --> 00:18:44,679
Speaker 1: an electron and you spin it, it creates a field

408
00:18:44,840 --> 00:18:47,560
Speaker 1: around it, or like it hasn't affect on the things

409
00:18:47,600 --> 00:18:49,959
Speaker 1: around it, so that if you throw another electron near

410
00:18:50,000 --> 00:18:52,280
Speaker 1: that spinning electron, then it's going to curve a certain way,

411
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Speaker 1: depending on whether you're going like in the direction or

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Speaker 1: near its north and south poles. That's just the weird

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Speaker 1: thing that happens, right.

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Speaker 2: Yeah, I guess you could say allophysics is explaining the

415
00:19:02,359 --> 00:19:05,200
Speaker 2: weird things that happen. And if you're not really comfortable

416
00:19:05,240 --> 00:19:07,120
Speaker 2: with the idea of like quantum spin, you can also

417
00:19:07,200 --> 00:19:09,840
Speaker 2: just take electrons and run them in a circle. You

418
00:19:09,880 --> 00:19:11,960
Speaker 2: take a wire and you coil it and you pass

419
00:19:12,000 --> 00:19:14,879
Speaker 2: a current through it. That's electrons moving in a circle.

420
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Speaker 2: That will generate a magnetic field, which will bend the

421
00:19:17,560 --> 00:19:21,280
Speaker 2: path of other electrically charged particles. But the key thing

422
00:19:21,440 --> 00:19:23,600
Speaker 2: is that all of the magnetic fields we've seen in

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Speaker 2: the universe are generated by the motion of electric charges

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Speaker 2: or the spinning of those electric charges, and those generate dipoles,

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Speaker 2: a combination of a north and a south. In principle,

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Speaker 2: by symmetry, you might imagine, why aren't there particles that

427
00:19:37,520 --> 00:19:40,120
Speaker 2: can generate a pure north or pure south the way

428
00:19:40,119 --> 00:19:43,800
Speaker 2: an electron can generate a pure positive or negatively charged

429
00:19:43,840 --> 00:19:44,679
Speaker 2: electric field.

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Speaker 1: Well, it kind of seems like maybe there isn't such

431
00:19:47,480 --> 00:19:50,679
Speaker 1: a thing as a magnetic charge. Is there such a

432
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Speaker 1: thing as a magnetic charge? Isn't it more like? I

433
00:19:52,680 --> 00:19:54,560
Speaker 1: don't know, but maybe does it maybe have more to

434
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Speaker 1: do with the direction that these electrons are spinning, Like

435
00:19:59,240 --> 00:20:01,399
Speaker 1: is there such a thing as a magnetic charge? Or

436
00:20:01,480 --> 00:20:03,879
Speaker 1: is it just a direction that electrons are spinning.

437
00:20:04,080 --> 00:20:06,600
Speaker 2: There's such a thing as the polarity of a magnetic field, right,

438
00:20:06,680 --> 00:20:08,600
Speaker 2: Magnetic fields have a north and a south. When you

439
00:20:08,640 --> 00:20:10,760
Speaker 2: take two bar magnets, you try to push them together,

440
00:20:11,040 --> 00:20:13,720
Speaker 2: you flip one over, they'll repel instead of a tract. Right,

441
00:20:13,760 --> 00:20:17,119
Speaker 2: So there's definitely a direction to these magnetic fields. They

442
00:20:17,160 --> 00:20:19,840
Speaker 2: have a charge to them in that sense the same way, like,

443
00:20:19,880 --> 00:20:22,159
Speaker 2: what's the difference between a positive and negative charge? It

444
00:20:22,160 --> 00:20:24,919
Speaker 2: really is just defined by the effect of a field

445
00:20:24,960 --> 00:20:27,399
Speaker 2: on it. What's the difference between an electron and an

446
00:20:27,440 --> 00:20:29,480
Speaker 2: anti electron. They have a different charge, which means you

447
00:20:29,480 --> 00:20:31,920
Speaker 2: put them in an electric field that go in different directions.

448
00:20:32,119 --> 00:20:34,760
Speaker 2: That's sort of what charge means. And so in the

449
00:20:34,760 --> 00:20:38,040
Speaker 2: same way, there's two different kinds of magnetic fields. This's

450
00:20:38,280 --> 00:20:40,640
Speaker 2: the north and the south kind. We've only ever seen

451
00:20:40,680 --> 00:20:42,879
Speaker 2: them paired together. The way, for example, you can make

452
00:20:42,880 --> 00:20:45,359
Speaker 2: a dipole out of a positive and negative charge, putting

453
00:20:45,359 --> 00:20:48,240
Speaker 2: them together to have something an overall neutral but still

454
00:20:48,280 --> 00:20:50,359
Speaker 2: has an effect on stuff nearby because it has a

455
00:20:50,400 --> 00:20:54,240
Speaker 2: dipole field. We've only ever seen a magnetic dipole field.

456
00:20:54,240 --> 00:20:56,880
Speaker 2: So you're asking like, is there really a magnetic charge, Well,

457
00:20:57,040 --> 00:21:00,119
Speaker 2: there's a directionality to the magnetic field. We've never I've

458
00:21:00,119 --> 00:21:04,600
Speaker 2: seen a particle that has a pure magnetic charge by itself.

459
00:21:04,920 --> 00:21:07,680
Speaker 2: So in that sense, everything is generated from the electric charge.

460
00:21:07,720 --> 00:21:10,560
Speaker 2: But that doesn't mean that they don't exist. And actually

461
00:21:10,560 --> 00:21:13,400
Speaker 2: it would be theoretically beautiful and kind of symmetric if

462
00:21:13,440 --> 00:21:16,800
Speaker 2: they did exist. It would complete these equations in this

463
00:21:16,840 --> 00:21:18,040
Speaker 2: sort of very nice way.

464
00:21:18,160 --> 00:21:19,600
Speaker 1: I guess maybe what I'm trying to say is that

465
00:21:19,640 --> 00:21:23,280
Speaker 1: like an electron, right has electric charge and it has

466
00:21:23,480 --> 00:21:26,520
Speaker 1: a spin direction, but it doesn't really have like a

467
00:21:26,520 --> 00:21:30,720
Speaker 1: magnetic label or value or quantum quantity.

468
00:21:30,240 --> 00:21:32,040
Speaker 2: To it, right, it does not, You're correct.

469
00:21:32,200 --> 00:21:36,160
Speaker 1: The magnetic field and it's magnetic field direction comes from

470
00:21:36,560 --> 00:21:38,480
Speaker 1: the charge and the spin and in the same way

471
00:21:38,560 --> 00:21:40,760
Speaker 1: like for your fridge magnet. It's not like it's a

472
00:21:41,000 --> 00:21:43,080
Speaker 1: property of the things in it. It's just that the

473
00:21:43,520 --> 00:21:46,040
Speaker 1: electrons inside of that magnet are all spinning in a

474
00:21:46,040 --> 00:21:46,480
Speaker 1: certain way.

475
00:21:46,560 --> 00:21:46,720
Speaker 3: Right.

476
00:21:46,840 --> 00:21:49,600
Speaker 2: Yes, all magnetism we know of in the whole universe

477
00:21:49,680 --> 00:21:52,160
Speaker 2: are just dipoles or combinations of north and south, which

478
00:21:52,200 --> 00:21:56,120
Speaker 2: are generated from the electric charges. Fundamentally, but that doesn't

479
00:21:56,160 --> 00:21:58,960
Speaker 2: mean the only thing that can happen. It might be

480
00:21:59,160 --> 00:22:01,800
Speaker 2: that there are parts of out there that have a

481
00:22:02,040 --> 00:22:05,160
Speaker 2: magnetic charge the way the electron has an electric charge.

482
00:22:05,320 --> 00:22:07,800
Speaker 2: That would be a magnetic monopole. That's the question.

483
00:22:08,000 --> 00:22:10,000
Speaker 1: All right, Well, let's dig into that question a little

484
00:22:10,040 --> 00:22:14,080
Speaker 1: bit more, and also how physinessists are trying to look

485
00:22:14,119 --> 00:22:16,920
Speaker 1: for these monopolies in nature. But first let's take a

486
00:22:17,000 --> 00:22:31,760
Speaker 1: quick break. All Right, we're talking about a very magnetic

487
00:22:31,800 --> 00:22:35,840
Speaker 1: subject here today, magnetic monopoles and whether they exist or

488
00:22:35,880 --> 00:22:39,080
Speaker 1: can exist in how we're actually looking for them now, Daniel,

489
00:22:39,080 --> 00:22:41,080
Speaker 1: I guess I'm kind of confused here. It seems like

490
00:22:41,119 --> 00:22:43,480
Speaker 1: magnetic fields are just kind of what happens when you

491
00:22:43,520 --> 00:22:46,560
Speaker 1: take an electric charge and you spin it right, either

492
00:22:46,640 --> 00:22:49,280
Speaker 1: quantum spin or you actually like physically make an electron

493
00:22:49,359 --> 00:22:51,320
Speaker 1: go around in a circle. You create a magnetic field.

494
00:22:51,359 --> 00:22:53,479
Speaker 1: And a magnetic field is sort of defined by that

495
00:22:53,560 --> 00:22:56,080
Speaker 1: right by its direction, Like if you spin it, Let's

496
00:22:56,119 --> 00:22:59,720
Speaker 1: say I spin an electron clockwise, it's going to generate.

497
00:23:00,119 --> 00:23:02,800
Speaker 1: Can I feel in like going up or going down right?

498
00:23:03,280 --> 00:23:06,800
Speaker 1: And so I feel like going up or down automatically

499
00:23:07,200 --> 00:23:09,359
Speaker 1: gives you a diepole because you need an up and

500
00:23:09,400 --> 00:23:12,040
Speaker 1: a down to the fine a direction, And so I

501
00:23:12,080 --> 00:23:15,000
Speaker 1: don't even know what a monopole would look like, Like

502
00:23:15,040 --> 00:23:17,600
Speaker 1: how can something have the same direction from all sides.

503
00:23:17,440 --> 00:23:19,520
Speaker 2: Same way an electric field does? You have an electron

504
00:23:19,680 --> 00:23:22,600
Speaker 2: in empty space that has an electric field which you

505
00:23:22,640 --> 00:23:24,960
Speaker 2: know either points towards the electron or away from the

506
00:23:25,040 --> 00:23:29,359
Speaker 2: electron in every direction simultaneously. Right, there's a total overall

507
00:23:29,560 --> 00:23:32,840
Speaker 2: charge there. It's like a source of electric charge.

508
00:23:33,040 --> 00:23:35,000
Speaker 1: So then how would it act on something else? Like

509
00:23:35,640 --> 00:23:38,880
Speaker 1: let's say that a mono magnetic monopole did exist. Let's

510
00:23:38,880 --> 00:23:41,119
Speaker 1: say I have one in my hand, and now I

511
00:23:41,119 --> 00:23:44,040
Speaker 1: have a magnet on my other hand with a north

512
00:23:44,040 --> 00:23:46,439
Speaker 1: and a south pole. What would this thing do? It

513
00:23:46,440 --> 00:23:49,159
Speaker 1: would only attract the north part of my magnet or

514
00:23:49,160 --> 00:23:49,840
Speaker 1: something like that.

515
00:23:49,960 --> 00:23:52,560
Speaker 2: If you're holding a north charge and then you have

516
00:23:52,640 --> 00:23:54,959
Speaker 2: another north charge, they would repel. If you have a

517
00:23:55,000 --> 00:23:57,520
Speaker 2: south charge, they would attract. You can apply all of

518
00:23:57,560 --> 00:23:59,960
Speaker 2: your intuition from electricity because we think the things are

519
00:24:00,080 --> 00:24:03,919
Speaker 2: perfectly symmetric. The equations should be the same. So if

520
00:24:03,960 --> 00:24:06,200
Speaker 2: you think, like, well, what happens to a neutral atom

521
00:24:06,280 --> 00:24:09,360
Speaker 2: if I have an electron nearby, Well, the electron repels

522
00:24:09,359 --> 00:24:12,000
Speaker 2: the other electron and attracts the proton. So if you

523
00:24:12,040 --> 00:24:13,720
Speaker 2: have a north charge in your hand and then you

524
00:24:13,720 --> 00:24:16,840
Speaker 2: have a dipole nearby, then it will attract the south

525
00:24:16,880 --> 00:24:18,919
Speaker 2: part of the dipole and repel the north part of

526
00:24:18,920 --> 00:24:22,280
Speaker 2: the dipole. That dipole will align itself in that magnetic field.

527
00:24:22,600 --> 00:24:25,600
Speaker 1: I see, repel the north part. But what will attract

528
00:24:25,600 --> 00:24:27,040
Speaker 1: the south part of my magnet?

529
00:24:27,240 --> 00:24:28,160
Speaker 2: Exactly? Yeah?

530
00:24:28,200 --> 00:24:30,200
Speaker 1: What if I have like a spinning electron.

531
00:24:31,240 --> 00:24:34,200
Speaker 2: A spinning electron will create a dipole field, right, so

532
00:24:34,280 --> 00:24:35,600
Speaker 2: then you'll have two dipoles.

533
00:24:35,760 --> 00:24:37,520
Speaker 1: Oh, I think I see the difference. Like, if I

534
00:24:37,520 --> 00:24:40,560
Speaker 1: have a monopole in my left hand and a dipole

535
00:24:40,560 --> 00:24:42,919
Speaker 1: in my right hand, the forces it exerts on my

536
00:24:43,080 --> 00:24:46,280
Speaker 1: right dipole magnet are always going to be sort of

537
00:24:46,280 --> 00:24:50,080
Speaker 1: pointing away from the north monopole. Right, That's kind of

538
00:24:50,119 --> 00:24:51,919
Speaker 1: what it means to have a monopole. Whereas if I

539
00:24:51,960 --> 00:24:55,560
Speaker 1: had a dipole in each hand, how they affect each

540
00:24:55,560 --> 00:24:57,560
Speaker 1: other sort of depends on how I twist my hands

541
00:24:57,640 --> 00:24:59,840
Speaker 1: or in what direction or where I put them relative

542
00:24:59,880 --> 00:25:02,800
Speaker 1: to each other. But a monopole magnetic monopole would sort

543
00:25:02,800 --> 00:25:05,119
Speaker 1: of act like a point particles that I think is

544
00:25:05,119 --> 00:25:08,200
Speaker 1: what you're saying. It would like exert forces the same

545
00:25:08,280 --> 00:25:09,160
Speaker 1: in all directions.

546
00:25:09,840 --> 00:25:12,600
Speaker 2: And theoretically this comes from exactly the kind of questions

547
00:25:12,640 --> 00:25:16,000
Speaker 2: you're asking. You're basically saying, it seems like magnetism is

548
00:25:16,040 --> 00:25:19,040
Speaker 2: like just a part of electricity, right, because electricity is

549
00:25:19,080 --> 00:25:21,880
Speaker 2: really the source of everything. But the theory says, well,

550
00:25:21,880 --> 00:25:25,040
Speaker 2: if electric sources can generate magnetic fields, why can't we

551
00:25:25,119 --> 00:25:29,480
Speaker 2: have like magnetic sources that generate electric fields, right? Why

552
00:25:29,520 --> 00:25:32,040
Speaker 2: can't we do that? Also? Why isn't there a symmetry there?

553
00:25:32,400 --> 00:25:34,560
Speaker 2: Why can't we have things that are just sources of

554
00:25:34,600 --> 00:25:38,320
Speaker 2: magnetic fields and then when they spin they make electric dipoles.

555
00:25:38,359 --> 00:25:41,080
Speaker 2: Or if you have a current of magnetic sources that

556
00:25:41,119 --> 00:25:43,919
Speaker 2: would generate an electric field the same way a current

557
00:25:43,960 --> 00:25:46,879
Speaker 2: of electric charges would generate a magnetic field. Wouldn't it

558
00:25:46,880 --> 00:25:49,600
Speaker 2: be awesome if there was symmetry to them? And if

559
00:25:49,640 --> 00:25:53,160
Speaker 2: you look at the equations Maxwell's equations for electromagnetism, there

560
00:25:53,240 --> 00:25:56,840
Speaker 2: is this weird asymmetry. The universe seems to prefer electricity.

561
00:25:56,880 --> 00:25:59,159
Speaker 2: It seems to be more primary, and that's because we

562
00:25:59,320 --> 00:26:02,600
Speaker 2: have electric charges. And if you say, well, actually, what

563
00:26:02,680 --> 00:26:05,160
Speaker 2: if there are monopoles in the universe and you change

564
00:26:05,400 --> 00:26:09,760
Speaker 2: Maxwell's equations to allow for monopoles, then they become perfectly symmetric.

565
00:26:10,080 --> 00:26:12,720
Speaker 2: All the equations are just like mirror images of each other.

566
00:26:12,920 --> 00:26:15,840
Speaker 2: Electricity and magnetism is just two sides of exactly the

567
00:26:15,880 --> 00:26:18,919
Speaker 2: same coin. So if there were monopoles, it would be

568
00:26:18,920 --> 00:26:23,240
Speaker 2: this like beautiful theoretical clicking together of these two pieces.

569
00:26:23,640 --> 00:26:26,480
Speaker 1: Hmmm, interesting, I guess maybe I wonder if the big

570
00:26:26,560 --> 00:26:29,239
Speaker 1: question is really sort of related to the idea that,

571
00:26:30,520 --> 00:26:33,920
Speaker 1: like we don't really know why spinning charges create magnetic fields.

572
00:26:33,960 --> 00:26:34,480
Speaker 1: Do we know that?

573
00:26:34,640 --> 00:26:36,800
Speaker 2: I guess it depends on what kind of answer you're

574
00:26:36,840 --> 00:26:40,800
Speaker 2: looking for for why. I mean, we know that it happens.

575
00:26:40,960 --> 00:26:44,520
Speaker 2: We have a mathematical description of it. We've invented this

576
00:26:44,680 --> 00:26:47,119
Speaker 2: concept of a field to explain like the forces on

577
00:26:47,240 --> 00:26:50,639
Speaker 2: particles in the vicinity of moving charges. What kind of

578
00:26:50,680 --> 00:26:51,840
Speaker 2: why are you looking for?

579
00:26:52,080 --> 00:26:54,400
Speaker 1: Like if I have a spinning electron on my right

580
00:26:54,440 --> 00:26:57,720
Speaker 1: hand and a spinning electron on my left hand, why

581
00:26:57,760 --> 00:27:00,320
Speaker 1: does the spinning electron in my right hand one make

582
00:27:00,400 --> 00:27:03,280
Speaker 1: this other spinning electron spin in the same direction?

583
00:27:03,520 --> 00:27:05,040
Speaker 2: I think actually they want to make each other spin

584
00:27:05,080 --> 00:27:06,440
Speaker 2: any opposite directions.

585
00:27:06,200 --> 00:27:07,040
Speaker 1: Right, opposite directions?

586
00:27:07,119 --> 00:27:08,720
Speaker 2: Yeah, oh yeah, that's a good question. You know in

587
00:27:08,800 --> 00:27:11,800
Speaker 2: our universe, that's what happens, right, we see, that's what happens.

588
00:27:11,880 --> 00:27:13,600
Speaker 2: And if you try to make an explanation for it

589
00:27:13,640 --> 00:27:17,080
Speaker 2: without magnetic fields, it doesn't work. If you add this

590
00:27:17,119 --> 00:27:19,960
Speaker 2: thing called the magnetic field, then it does work. Right,

591
00:27:20,119 --> 00:27:23,080
Speaker 2: So far, just descriptive. You know, you're basically asking, like,

592
00:27:23,119 --> 00:27:25,439
Speaker 2: why do you have magnetic fields? Could you have a

593
00:27:25,520 --> 00:27:28,719
Speaker 2: universe without magnetic fields? You certainly could, But our universe

594
00:27:28,760 --> 00:27:30,760
Speaker 2: seems to have them. You're asking, could you have a

595
00:27:30,840 --> 00:27:34,120
Speaker 2: universe without magnetic fields? I think that would be more complicated.

596
00:27:34,119 --> 00:27:36,480
Speaker 2: It would be a very different universe. You wouldn't have light,

597
00:27:36,640 --> 00:27:38,879
Speaker 2: for example. So I'm not sure you could have a

598
00:27:39,000 --> 00:27:41,480
Speaker 2: universe without magnetic fields. I think maybe that's the question

599
00:27:41,520 --> 00:27:43,119
Speaker 2: you're asking, like why are they here?

600
00:27:43,359 --> 00:27:45,480
Speaker 1: No, I think I'm more asking, like, you know, how

601
00:27:45,600 --> 00:27:47,840
Speaker 1: like in space, if you have a whole bunch of

602
00:27:47,920 --> 00:27:51,920
Speaker 1: rocks twirling around an object like the Sun for example,

603
00:27:52,040 --> 00:27:54,399
Speaker 1: their orbits are going to collapse down into a disc

604
00:27:54,640 --> 00:27:57,919
Speaker 1: because like the forces balance out in the direction that

605
00:27:57,960 --> 00:28:01,080
Speaker 1: they're not spinning around the Sun, but they don't align.

606
00:28:01,680 --> 00:28:05,160
Speaker 1: You know, there's like a mechanical explanation for why orbits

607
00:28:05,200 --> 00:28:06,439
Speaker 1: tend to be discs.

608
00:28:06,600 --> 00:28:09,680
Speaker 2: Yeah, that comes from conservation of angular momentum, right.

609
00:28:09,600 --> 00:28:11,600
Speaker 1: Right, right. So Now, like if I have a spinning

610
00:28:11,600 --> 00:28:14,240
Speaker 1: electron on my right hand, I wonder I'm just wondering

611
00:28:14,400 --> 00:28:17,800
Speaker 1: if maybe it wants to make the other electron spin

612
00:28:17,880 --> 00:28:20,440
Speaker 1: in the opposite way, because if it's spinning, you know

613
00:28:20,440 --> 00:28:23,080
Speaker 1: what I mean, Like the motion plus the electric forces

614
00:28:23,240 --> 00:28:27,160
Speaker 1: somehow make it so that if they're spinning in opposite directions.

615
00:28:27,160 --> 00:28:29,080
Speaker 1: That's the most balanced way that they can be.

616
00:28:29,200 --> 00:28:31,920
Speaker 2: I don't think there's a simple mechanical explanation for it

617
00:28:32,119 --> 00:28:34,120
Speaker 2: in that sense. It's just that the kind of thing

618
00:28:34,160 --> 00:28:36,960
Speaker 2: we see happen in our universe, and I think that

619
00:28:37,000 --> 00:28:40,000
Speaker 2: theoretically it'd be pretty hard to build the universe without

620
00:28:40,080 --> 00:28:42,880
Speaker 2: magnetic fields. To me, that's the best answer for why

621
00:28:42,920 --> 00:28:46,120
Speaker 2: they're here. You know, it's something we see that happens,

622
00:28:46,160 --> 00:28:48,160
Speaker 2: and we don't know how to build a universe without it.

623
00:28:48,240 --> 00:28:50,640
Speaker 1: All right, maybe that's the answer. It's just the way

624
00:28:50,640 --> 00:28:50,880
Speaker 1: it is.

625
00:28:51,600 --> 00:28:53,240
Speaker 2: It is just the way it is. But in terms

626
00:28:53,280 --> 00:28:56,320
Speaker 2: of balance, it's like fascinating that the universe has all

627
00:28:56,320 --> 00:28:58,320
Speaker 2: these electric charges in it. We see them all over

628
00:28:58,360 --> 00:29:01,480
Speaker 2: the place, but we've never seen a magnetic charge, and

629
00:29:01,520 --> 00:29:05,200
Speaker 2: it would be so beautiful and symmetric if it did not,

630
00:29:05,280 --> 00:29:08,400
Speaker 2: only because it would like balance the equations of maxwell

631
00:29:08,400 --> 00:29:11,280
Speaker 2: in this way that like, let us have electric charges

632
00:29:11,320 --> 00:29:14,880
Speaker 2: generating magnetic field and magnetic charges generating electric fields and

633
00:29:14,880 --> 00:29:17,200
Speaker 2: all sorts of stuff. But it would also answer other

634
00:29:17,360 --> 00:29:21,400
Speaker 2: deep theoretical questions we have, like why is electric charge

635
00:29:21,480 --> 00:29:24,680
Speaker 2: quantized at all? Like why is electric charge always this

636
00:29:24,760 --> 00:29:28,320
Speaker 2: weird number of rational number one, third two third minus

637
00:29:28,320 --> 00:29:31,120
Speaker 2: one plus two. Why is it never like zero point

638
00:29:31,200 --> 00:29:32,000
Speaker 2: seventy one four?

639
00:29:33,520 --> 00:29:36,040
Speaker 1: All right, So it sounds like breaking this problem or

640
00:29:36,040 --> 00:29:38,520
Speaker 1: figuring it out would tell us about why things are

641
00:29:38,560 --> 00:29:40,880
Speaker 1: the way they are, which is my question in the

642
00:29:40,920 --> 00:29:41,440
Speaker 1: first place.

643
00:29:42,800 --> 00:29:44,720
Speaker 2: Yeah, it's really interesting, and it actually does have to

644
00:29:44,720 --> 00:29:46,560
Speaker 2: do with angular momentum, as you were talking about a

645
00:29:46,560 --> 00:29:50,480
Speaker 2: minute ago. In our universe, angular momentum is quantized, right,

646
00:29:50,560 --> 00:29:53,800
Speaker 2: how fast things spin around. Other things can't just have

647
00:29:54,000 --> 00:29:58,160
Speaker 2: any arbitrary value. They have to be quantized, like linear momentum,

648
00:29:58,360 --> 00:30:01,239
Speaker 2: how fast you're moving through space, how much momentum you have,

649
00:30:01,320 --> 00:30:03,800
Speaker 2: your mass times your velocity doesn't have to be quantized,

650
00:30:03,840 --> 00:30:07,200
Speaker 2: it can be any number, but your angular momentum. Right,

651
00:30:07,240 --> 00:30:10,800
Speaker 2: How the momentum of spinning does have to be quantized

652
00:30:10,840 --> 00:30:13,640
Speaker 2: in our universe. That's a really fascinating fact. But if

653
00:30:13,680 --> 00:30:16,479
Speaker 2: you have magnetic monopoles in the universe, you have electric

654
00:30:16,560 --> 00:30:19,480
Speaker 2: charge particle and a magnetically charged particle, then their angular

655
00:30:19,520 --> 00:30:22,960
Speaker 2: momentum is related to the product of their two charges,

656
00:30:23,280 --> 00:30:25,560
Speaker 2: like the amount of magnetic charge and the amount of

657
00:30:25,560 --> 00:30:28,480
Speaker 2: electric charge. And because the product has to be quantized,

658
00:30:28,640 --> 00:30:31,560
Speaker 2: that means they both have to be quantized. So if

659
00:30:31,600 --> 00:30:34,920
Speaker 2: there's a single magnetic monopole anywhere in the universe that

660
00:30:35,000 --> 00:30:38,040
Speaker 2: dates angular momentum has to be quantized, which means its

661
00:30:38,160 --> 00:30:41,320
Speaker 2: charge has to be quantized, and so does electric charge.

662
00:30:41,800 --> 00:30:45,640
Speaker 2: So if magnetic monopoles exist, then electric and magnetic charges

663
00:30:45,680 --> 00:30:47,200
Speaker 2: both have to be quantized.

664
00:30:47,320 --> 00:30:49,560
Speaker 1: I think you're saying that you know, are electric charges

665
00:30:49,720 --> 00:30:52,480
Speaker 1: are quantized? Like can you have just any amount of

666
00:30:52,720 --> 00:30:55,080
Speaker 1: electric charge right now? As far as we.

667
00:30:55,040 --> 00:30:57,280
Speaker 2: Know they are quantized. You cannot just have like an

668
00:30:57,360 --> 00:31:00,239
Speaker 2: arbitrary charge. You can't. We're not like seeing particles like

669
00:31:00,400 --> 00:31:03,280
Speaker 2: one point series or is there one to two electric charges?

670
00:31:03,320 --> 00:31:06,600
Speaker 2: And point nine nine nine seven electric charges? They seem

671
00:31:06,640 --> 00:31:08,720
Speaker 2: to be quantized in these discrete units.

672
00:31:09,120 --> 00:31:12,120
Speaker 1: But then magnetic charge it sort of depends on that

673
00:31:12,240 --> 00:31:14,080
Speaker 1: electric charge and how fast it's spinning.

674
00:31:14,280 --> 00:31:17,800
Speaker 2: Well, magnetic dipoles do, right, If there are magnetic monopoles,

675
00:31:17,840 --> 00:31:21,040
Speaker 2: there are north charges and south charges out there, then

676
00:31:21,080 --> 00:31:23,400
Speaker 2: you can also ask the question are those quantized? And

677
00:31:23,440 --> 00:31:26,560
Speaker 2: if so, then why The question is really like why

678
00:31:26,680 --> 00:31:29,360
Speaker 2: is electric charge? Why is any charge at all quantized?

679
00:31:29,400 --> 00:31:32,040
Speaker 2: Why isn't it just some arbitrary value. Why don't we

680
00:31:32,040 --> 00:31:34,480
Speaker 2: see like electrons out there with at big spectrum of

681
00:31:34,520 --> 00:31:37,000
Speaker 2: different charges. Why do they all have the same one?

682
00:31:37,080 --> 00:31:40,280
Speaker 1: Well, isn't it the case that electric charges quantized because

683
00:31:40,320 --> 00:31:42,440
Speaker 1: it's small at the unit that we know, and the

684
00:31:42,880 --> 00:31:44,120
Speaker 1: electron is a.

685
00:31:44,080 --> 00:31:45,720
Speaker 2: Particle, right, it is a particle.

686
00:31:45,760 --> 00:31:48,160
Speaker 1: Yeah, you're asking like, why can't electron have half of

687
00:31:48,160 --> 00:31:49,240
Speaker 1: them an electron charge?

688
00:31:49,320 --> 00:31:52,720
Speaker 2: Yeah? Or a real number right? Or an irrational charge?

689
00:31:52,760 --> 00:31:56,280
Speaker 2: Why is it always this integer or irrational ratio of

690
00:31:56,280 --> 00:31:58,800
Speaker 2: the integers? You know, we seem like one third or

691
00:31:59,040 --> 00:32:02,520
Speaker 2: minus two thirds or one seems to be quantized. Yes,

692
00:32:02,600 --> 00:32:04,760
Speaker 2: you're right, all electric charges are built out of electrons.

693
00:32:04,760 --> 00:32:07,680
Speaker 2: But the question is like why do particles themselves have

694
00:32:07,800 --> 00:32:11,520
Speaker 2: quantized electric charges? And the existence of a single magnetic

695
00:32:11,560 --> 00:32:15,400
Speaker 2: monopole in the universe would force all electric charges to

696
00:32:15,480 --> 00:32:19,760
Speaker 2: be quantized because their angular momentum depends on their charge.

697
00:32:19,760 --> 00:32:22,640
Speaker 2: An angular momentum we know has to be quantized. I

698
00:32:22,640 --> 00:32:25,440
Speaker 2: think the deep question is like why are things quantized?

699
00:32:25,520 --> 00:32:27,880
Speaker 2: To me? That's really fascinating, Like we could have had

700
00:32:27,920 --> 00:32:31,960
Speaker 2: a universe where particles have any random charge. Instead, we

701
00:32:32,000 --> 00:32:35,120
Speaker 2: seem to have a universe where particles have these fixed charges.

702
00:32:35,160 --> 00:32:37,760
Speaker 2: It's like a ladder of charges instead, of a spectrum,

703
00:32:38,120 --> 00:32:40,280
Speaker 2: and the question is why, and nobody really has an

704
00:32:40,280 --> 00:32:44,080
Speaker 2: answer to that except for this one explanation. If there's

705
00:32:44,080 --> 00:32:46,800
Speaker 2: a monopole out there in the universe, then particles have

706
00:32:46,840 --> 00:32:49,800
Speaker 2: to have quantized electric charges because it relates to their

707
00:32:49,840 --> 00:32:52,959
Speaker 2: angular momentum, which we already know has to be quantized.

708
00:32:53,040 --> 00:32:55,680
Speaker 2: We also think that magnetic monopoles were probably made in

709
00:32:55,720 --> 00:32:58,120
Speaker 2: the early universe, like when the Big Bang happened, it

710
00:32:58,200 --> 00:33:01,880
Speaker 2: made a bunch of particles of all, and if monopoles

711
00:33:01,920 --> 00:33:03,640
Speaker 2: are a thing, then a lot of them should have

712
00:33:03,720 --> 00:33:06,160
Speaker 2: also been made in the Big Bang and they should

713
00:33:06,240 --> 00:33:08,080
Speaker 2: still be flying around the universe.

714
00:33:08,320 --> 00:33:10,400
Speaker 1: But wait, I guess maybe the question is what would

715
00:33:10,400 --> 00:33:13,800
Speaker 1: this monopole be embodied in. Would it be a particle

716
00:33:13,840 --> 00:33:16,480
Speaker 1: with a monopole? Would it just be like a random

717
00:33:16,480 --> 00:33:19,440
Speaker 1: monopole that exists out there, like a random like magnet

718
00:33:19,480 --> 00:33:21,680
Speaker 1: floating out in space that has this Is it made

719
00:33:21,680 --> 00:33:23,880
Speaker 1: out of something or is it would it just exist?

720
00:33:24,040 --> 00:33:26,200
Speaker 2: It would be a new kind of particle, right, a

721
00:33:26,240 --> 00:33:29,080
Speaker 2: particle with some kind of mass and other properties you know, spin,

722
00:33:29,640 --> 00:33:33,280
Speaker 2: and it would have some kind of overall magnetic charge

723
00:33:33,720 --> 00:33:36,680
Speaker 2: the way electric charge doesn't just like float around unembodied

724
00:33:36,680 --> 00:33:39,880
Speaker 2: in the universe. It's attached to particles the same way

725
00:33:39,880 --> 00:33:42,280
Speaker 2: a magnetic charge would be attached to this new particle,

726
00:33:42,320 --> 00:33:45,360
Speaker 2: which we call a magnetic monopole. That would be the particle.

727
00:33:45,680 --> 00:33:48,680
Speaker 2: It's like the magnetic version of an electron, call it

728
00:33:48,720 --> 00:33:50,000
Speaker 2: the magnetron or whatever.

729
00:33:51,040 --> 00:33:53,880
Speaker 1: Okay, now see now you're talking about a whole new

730
00:33:53,960 --> 00:33:54,680
Speaker 1: kind of particle.

731
00:33:54,920 --> 00:33:57,280
Speaker 2: Yes, a whole new kind of particle exactly.

732
00:33:57,600 --> 00:34:00,280
Speaker 1: And so this new particle that we've had I haven't

733
00:34:00,280 --> 00:34:03,840
Speaker 1: seen yet so far would have mass maybe, and it

734
00:34:03,840 --> 00:34:07,200
Speaker 1: would also have electric charge or would not have electric charge.

735
00:34:07,280 --> 00:34:09,600
Speaker 2: It probably wouldn't have electric charge the way like an

736
00:34:09,600 --> 00:34:11,880
Speaker 2: electron doesn't have magnetic charge.

737
00:34:11,960 --> 00:34:15,240
Speaker 1: Okay, and so it we just have this magnetic charge

738
00:34:15,320 --> 00:34:18,520
Speaker 1: to a no spin either. Don't all particles need to

739
00:34:18,560 --> 00:34:18,919
Speaker 1: have spin.

740
00:34:19,120 --> 00:34:21,319
Speaker 2: Not all particles have spinned like the Higgs boson has

741
00:34:21,320 --> 00:34:24,480
Speaker 2: no spin, but every other particle does. And so this

742
00:34:24,560 --> 00:34:27,440
Speaker 2: particle probably would have spin. There's a bunch of different

743
00:34:27,520 --> 00:34:30,560
Speaker 2: theories of magnetic monopoles, but in most cases they have spin,

744
00:34:31,239 --> 00:34:35,400
Speaker 2: and a magnetic monopole spinning would create an electric dipole

745
00:34:35,760 --> 00:34:38,000
Speaker 2: the same way that an electron spinning has a little

746
00:34:38,040 --> 00:34:41,480
Speaker 2: magnetic field. A magnetic monopole spinning would have a little

747
00:34:41,520 --> 00:34:42,520
Speaker 2: electric field, all.

748
00:34:42,520 --> 00:34:45,560
Speaker 1: Right, And so then this new particle would somehow exist

749
00:34:45,600 --> 00:34:47,320
Speaker 1: in ems. But we haven't seen it before.

750
00:34:47,480 --> 00:34:51,120
Speaker 2: We've never seen one. Nobody has ever spotted a magnetic monopole.

751
00:34:51,160 --> 00:34:54,600
Speaker 1: Wouldn't we have noticed by now, you know, like there

752
00:34:54,680 --> 00:34:57,800
Speaker 1: are a bunch of north pole particles out there floating.

753
00:34:57,800 --> 00:35:00,719
Speaker 1: Wouldn't they have been attracted to our south pole we

754
00:35:00,800 --> 00:35:03,000
Speaker 1: have known? Is that they you know, our soft poles

755
00:35:03,000 --> 00:35:03,720
Speaker 1: are getting heavier.

756
00:35:03,800 --> 00:35:04,120
Speaker 3: M hm.

757
00:35:04,400 --> 00:35:08,439
Speaker 2: Exactly. If magnetic monopoles were as common as electrons, then

758
00:35:08,520 --> 00:35:11,239
Speaker 2: absolutely yes, we would have noticed them, and they would

759
00:35:11,280 --> 00:35:13,840
Speaker 2: have played a big role in life, and experience of

760
00:35:13,880 --> 00:35:16,520
Speaker 2: living in this universe would be very different, and magnetism

761
00:35:16,560 --> 00:35:19,040
Speaker 2: would be very different, and it would have then bubbled

762
00:35:19,120 --> 00:35:22,240
Speaker 2: up through our primary experience. And when Maxwell wrote his laws,

763
00:35:22,320 --> 00:35:25,360
Speaker 2: instead of making them asymmetric and basing everything on electric charges,

764
00:35:25,440 --> 00:35:28,960
Speaker 2: it would have written magnetic monopoles into his equations. But

765
00:35:29,120 --> 00:35:32,080
Speaker 2: magnetic monopoles, if they do exist, are very very rare.

766
00:35:32,239 --> 00:35:34,920
Speaker 2: They're either none in the universe or very very few

767
00:35:35,200 --> 00:35:36,399
Speaker 2: because we've never seen any.

768
00:35:36,480 --> 00:35:38,480
Speaker 1: Well, I guess that begs the question, how can we

769
00:35:38,520 --> 00:35:41,279
Speaker 1: look for them, and have we found any. So let's

770
00:35:41,360 --> 00:35:45,360
Speaker 1: dig into our search for this possibly imaginary maybe the

771
00:35:45,440 --> 00:35:48,480
Speaker 1: sense of making particle and what we're doing about it.

772
00:35:49,000 --> 00:36:04,960
Speaker 1: But first let's take another quick break. All right, you

773
00:36:05,040 --> 00:36:09,960
Speaker 1: have the monopoly today here on magnetic confusion for cartoonists,

774
00:36:10,800 --> 00:36:13,040
Speaker 1: and it sounds like there is a concept out there

775
00:36:13,080 --> 00:36:17,440
Speaker 1: called a monopole, which is maybe this theoretical or maybe

776
00:36:17,640 --> 00:36:21,799
Speaker 1: potential particle that might exist that has magnetic charge to it.

777
00:36:21,800 --> 00:36:25,320
Speaker 1: It attracts north and south or repels north and south

778
00:36:25,640 --> 00:36:29,040
Speaker 1: magnetic holes, but it doesn't really have a direction to it.

779
00:36:28,760 --> 00:36:31,680
Speaker 1: It only has either north or south to it as

780
00:36:31,719 --> 00:36:34,800
Speaker 1: an inherent property of its particleness.

781
00:36:34,080 --> 00:36:38,000
Speaker 2: Exactly, and nobody ever seen one in that sense, it's theoretical,

782
00:36:38,080 --> 00:36:41,759
Speaker 2: but it's also very theoretically motivated. Like the universe is

783
00:36:41,800 --> 00:36:43,440
Speaker 2: sort of weird and out of whack, it would make

784
00:36:43,440 --> 00:36:45,799
Speaker 2: a lot of sense to see monopoles the same way

785
00:36:45,840 --> 00:36:49,200
Speaker 2: the universe seems weird and out of whack without anti matter. Right,

786
00:36:49,200 --> 00:36:51,759
Speaker 2: the equations work for matter, and they should also work

787
00:36:51,800 --> 00:36:54,040
Speaker 2: for antimatter, and so Direc said, like, hmm, let's go

788
00:36:54,080 --> 00:36:56,239
Speaker 2: look for antimatter, and then we found it. It's not

789
00:36:56,360 --> 00:36:58,640
Speaker 2: very much of it. It's pretty rare, but it shows

790
00:36:58,680 --> 00:37:01,160
Speaker 2: us that the universe has this symmetry. It was also

791
00:37:01,280 --> 00:37:03,759
Speaker 2: direct who said maybe we should go look for monopoles

792
00:37:04,080 --> 00:37:07,440
Speaker 2: as this sort of symmetric version of electrically charged particles.

793
00:37:07,960 --> 00:37:09,400
Speaker 2: So it would make a lot of sense if it

794
00:37:09,480 --> 00:37:11,919
Speaker 2: existed in the universe, but so far we've never seen one.

795
00:37:12,200 --> 00:37:14,839
Speaker 1: Okay, which begs the questions are we looking for them?

796
00:37:14,920 --> 00:37:17,680
Speaker 1: Are physicists trying to find these or just sitting back

797
00:37:17,680 --> 00:37:19,280
Speaker 1: on their couch wondering if they exists.

798
00:37:21,200 --> 00:37:24,280
Speaker 2: Some physicists are trekking out to the South Pole building

799
00:37:24,400 --> 00:37:27,720
Speaker 2: crazy amazing telescopes out of the ice in the South

800
00:37:27,760 --> 00:37:30,880
Speaker 2: Pole to look for neutrinos but also to look for

801
00:37:31,000 --> 00:37:32,160
Speaker 2: magnetic monopoles.

802
00:37:32,440 --> 00:37:35,000
Speaker 1: Nice. So this is a famous experiment, or a big experiment.

803
00:37:35,040 --> 00:37:36,919
Speaker 2: It's a famous and big experiment. There's a big group

804
00:37:36,960 --> 00:37:38,960
Speaker 2: here at you see Irvine that works on it. It's

805
00:37:38,960 --> 00:37:43,200
Speaker 2: called the Ice Cube Neutrino Observatory, and it literally is

806
00:37:43,239 --> 00:37:46,960
Speaker 2: an ice cube. They take a cubic kilometer of ice

807
00:37:47,440 --> 00:37:50,520
Speaker 2: on the South Pole, they drill holes in it, and

808
00:37:50,560 --> 00:37:54,040
Speaker 2: they bury cameras on these long strings within the ice.

809
00:37:54,600 --> 00:37:58,240
Speaker 2: So they basically have instrumented a cubic kilometer of ice

810
00:37:58,400 --> 00:38:01,920
Speaker 2: looking for flashes of light of particles traveling through that ice.

811
00:38:02,120 --> 00:38:04,480
Speaker 1: Wait, what, so they just take like an ice shelf

812
00:38:04,480 --> 00:38:07,600
Speaker 1: down in Antarctica and they drill down like a kilometer

813
00:38:07,719 --> 00:38:12,600
Speaker 1: or two, and they rope down cameras instruments. But then

814
00:38:12,640 --> 00:38:15,359
Speaker 1: they're pretty far apart from each other, aren't they.

815
00:38:15,440 --> 00:38:18,160
Speaker 2: Yeah, they have like ninety of these strings. Each one

816
00:38:18,239 --> 00:38:21,439
Speaker 2: is like one to two kilometers long. And as you say,

817
00:38:21,480 --> 00:38:24,960
Speaker 2: they drill these crazy deep holes in the ice and

818
00:38:25,000 --> 00:38:27,480
Speaker 2: then they have these strings. So every string has like

819
00:38:27,520 --> 00:38:29,680
Speaker 2: a lot of cameras on it, a lot of these

820
00:38:29,760 --> 00:38:33,640
Speaker 2: light sensors. They lower those down into these holes and

821
00:38:33,640 --> 00:38:35,840
Speaker 2: then they pour water in so the whole thing freezes

822
00:38:35,920 --> 00:38:38,520
Speaker 2: up again. So then you have this cubic kilometer of

823
00:38:38,520 --> 00:38:41,960
Speaker 2: ice with about five thousand sensors distributed through it. You're right,

824
00:38:41,960 --> 00:38:45,320
Speaker 2: they're not like equally distributed. They'd love to have more strings,

825
00:38:45,320 --> 00:38:47,040
Speaker 2: but this is sort of the best they can do.

826
00:38:47,239 --> 00:38:48,960
Speaker 1: So then how are they looking for monopoles?

827
00:38:49,120 --> 00:38:51,000
Speaker 2: So what you can do with this ice is you

828
00:38:51,040 --> 00:38:54,399
Speaker 2: can look for Cherenkov light. That's light that particles emit

829
00:38:54,440 --> 00:38:57,960
Speaker 2: when they fly through material. Faster than photons can fly

830
00:38:58,200 --> 00:39:01,600
Speaker 2: through that material, where you can't move faster than light

831
00:39:01,760 --> 00:39:04,120
Speaker 2: in a vacuum. But when light moves through ice, it

832
00:39:04,160 --> 00:39:06,960
Speaker 2: moves that's slower than the speed of light in a vacuum,

833
00:39:06,960 --> 00:39:09,280
Speaker 2: and particles don't always have to follow that same limit.

834
00:39:09,719 --> 00:39:12,080
Speaker 2: So if a muon, for example, is moving through the

835
00:39:12,120 --> 00:39:15,359
Speaker 2: ice faster than a photon could, it creates this sort

836
00:39:15,360 --> 00:39:18,680
Speaker 2: of superluminal wake. The way, for example, if you're on

837
00:39:18,760 --> 00:39:21,719
Speaker 2: a jet ski in a lake, you're creating a wake

838
00:39:21,880 --> 00:39:24,759
Speaker 2: behind you because the boat that's making the ripples is

839
00:39:24,760 --> 00:39:27,640
Speaker 2: moving faster than the ripples, so the ripples sort of

840
00:39:27,680 --> 00:39:30,440
Speaker 2: like add up to make this wake, this cone of

841
00:39:30,520 --> 00:39:33,480
Speaker 2: ripples behind you. The same way, particles moving through this

842
00:39:33,560 --> 00:39:36,920
Speaker 2: material emit this special light, this cherankof light in a

843
00:39:37,080 --> 00:39:39,640
Speaker 2: cone as they move, so you can use this to

844
00:39:39,680 --> 00:39:43,279
Speaker 2: spot particles moving really really fast through the ice. And

845
00:39:43,320 --> 00:39:45,520
Speaker 2: they build this thing not to look for monopoles, but

846
00:39:45,600 --> 00:39:48,800
Speaker 2: to look for neutrinos that move up through the Earth.

847
00:39:48,880 --> 00:39:50,759
Speaker 2: So they come from the Sun or somewhere out in

848
00:39:50,840 --> 00:39:54,160
Speaker 2: deep space, they move up through the Earth, interact somewhere

849
00:39:54,200 --> 00:39:56,600
Speaker 2: in the Earth, and they create like a muon which

850
00:39:56,640 --> 00:39:58,840
Speaker 2: flies through the ice, and that tells them that a

851
00:39:58,920 --> 00:40:02,000
Speaker 2: neutrino was there. That's why they built this experiment as

852
00:40:02,040 --> 00:40:03,359
Speaker 2: a neutrino observatory.

853
00:40:03,440 --> 00:40:05,719
Speaker 1: Wait, so they built it to technittrinos, but you can

854
00:40:05,800 --> 00:40:10,120
Speaker 1: also use it to potentially a monopole particle exactly.

855
00:40:10,160 --> 00:40:12,840
Speaker 2: This is one of the clever like reapplications of these things.

856
00:40:13,040 --> 00:40:15,200
Speaker 2: They build it for one thing, but then they realize, actually,

857
00:40:15,239 --> 00:40:17,640
Speaker 2: we could also use this to look for something else,

858
00:40:18,200 --> 00:40:20,600
Speaker 2: because a muon and a monopole going through the ice

859
00:40:20,600 --> 00:40:24,320
Speaker 2: would look very very different. Magnetic monopoles, if they exist,

860
00:40:24,320 --> 00:40:27,880
Speaker 2: would make a spectacular signature in the ice. Because of

861
00:40:27,920 --> 00:40:31,759
Speaker 2: this relationship between the magnetic and electric charges. We know

862
00:40:31,840 --> 00:40:35,000
Speaker 2: that the minimum magnetic charge of a monopole, if it exists,

863
00:40:35,160 --> 00:40:38,480
Speaker 2: is basically the equivalent of like sixty eight electric charges.

864
00:40:38,600 --> 00:40:41,399
Speaker 2: So a magnetic monopole, if it exists, it's like very

865
00:40:41,560 --> 00:40:44,879
Speaker 2: very magnetically charged. So when it flies through the ice,

866
00:40:44,960 --> 00:40:47,719
Speaker 2: it would create like a series of brilliant flashes of

867
00:40:47,719 --> 00:40:48,640
Speaker 2: this drank off light.

868
00:40:48,840 --> 00:40:51,080
Speaker 1: Wait, I guess there's so many questions there. Why do

869
00:40:51,120 --> 00:40:54,520
Speaker 1: you think a monocle would be so magnetically charged? Firs,

870
00:40:54,640 --> 00:40:56,600
Speaker 1: Whill where does that guess?

871
00:40:56,600 --> 00:40:59,080
Speaker 2: Come from. So it comes from this argument that electric

872
00:40:59,120 --> 00:41:02,600
Speaker 2: and magnetic charging are connected by angular momentum. Parames to

873
00:41:02,600 --> 00:41:04,719
Speaker 2: the two has to be quantized because that's related to

874
00:41:04,800 --> 00:41:07,640
Speaker 2: angular momentum. So that let's you actually calculate what the

875
00:41:07,680 --> 00:41:12,040
Speaker 2: minimum magnetic charge has to be. If that argument holds,

876
00:41:12,120 --> 00:41:14,920
Speaker 2: it's sort of like the fine structure constant over two,

877
00:41:15,040 --> 00:41:17,279
Speaker 2: So that's like one thirty seven over two. So the

878
00:41:17,280 --> 00:41:20,040
Speaker 2: minimum magnetic charge has to be like sixty eight and

879
00:41:20,120 --> 00:41:23,880
Speaker 2: a half times the electric charge. So basically, if there

880
00:41:23,880 --> 00:41:27,080
Speaker 2: are magnetic monopoles out there, they are very very magnetic.

881
00:41:27,160 --> 00:41:28,840
Speaker 2: They're not just like a little bit magnetic.

882
00:41:29,800 --> 00:41:32,760
Speaker 1: And so as it goes through the ice, this particle

883
00:41:32,800 --> 00:41:34,680
Speaker 1: wouldn't interact with the water molecules.

884
00:41:34,800 --> 00:41:37,400
Speaker 2: It would interact with the water molecules. That's what generates

885
00:41:37,400 --> 00:41:40,080
Speaker 2: the trenk Off radiation is the interaction of this particle

886
00:41:40,160 --> 00:41:43,560
Speaker 2: with the electromagnetic fields of the water. That's what generates

887
00:41:43,560 --> 00:41:47,359
Speaker 2: this radiation because it's interacting with the material it's moving through,

888
00:41:47,600 --> 00:41:50,719
Speaker 2: and that interaction would generate all of this radiation. It

889
00:41:50,719 --> 00:41:53,279
Speaker 2: wouldn't interact in the same way an electron interacts, right,

890
00:41:53,320 --> 00:41:56,840
Speaker 2: because electron has a different charge than a magnetic monopole

891
00:41:56,880 --> 00:42:00,239
Speaker 2: would and because this thing is basically more charge urged

892
00:42:00,400 --> 00:42:02,160
Speaker 2: than an electron is even though it also has a

893
00:42:02,160 --> 00:42:05,200
Speaker 2: different kind of charge, its magnitude is also greater. It

894
00:42:05,239 --> 00:42:09,280
Speaker 2: emits more radiation, like eight thousand times as much radiation.

895
00:42:10,360 --> 00:42:12,800
Speaker 1: I guess you know we talked last time about neutrinos

896
00:42:12,800 --> 00:42:15,040
Speaker 1: that they can go through things because they don't feel

897
00:42:15,600 --> 00:42:19,520
Speaker 1: the electromagnetic force, only the weak force. Right, But here

898
00:42:19,600 --> 00:42:22,359
Speaker 1: is something that is totally super magnetic. You're saying it's

899
00:42:22,440 --> 00:42:25,239
Speaker 1: very magnetic. Why wouldn't it sort of bounce around when

900
00:42:25,239 --> 00:42:28,920
Speaker 1: it hits or flies close to all of these water molecules?

901
00:42:28,960 --> 00:42:29,759
Speaker 1: Why would it keep going?

902
00:42:29,800 --> 00:42:31,680
Speaker 2: Yeah, that's a good question. If you shoot an electron

903
00:42:32,000 --> 00:42:34,120
Speaker 2: and a big blob of ice, it doesn't go all

904
00:42:34,120 --> 00:42:35,880
Speaker 2: the way through, right, it gets absorbed. But if you

905
00:42:35,920 --> 00:42:38,560
Speaker 2: shoot a muon through it. Muon, remember is an electron,

906
00:42:38,640 --> 00:42:41,120
Speaker 2: but with more mass it can penetrate through because it

907
00:42:41,160 --> 00:42:43,880
Speaker 2: has more mass, so it like has more momentum to

908
00:42:43,960 --> 00:42:46,360
Speaker 2: keep going. In a monopole, we think also would be

909
00:42:46,400 --> 00:42:49,560
Speaker 2: massive and so it would survive making it through the ice.

910
00:42:49,600 --> 00:42:52,520
Speaker 2: It's more like a muon than an electron, but also

911
00:42:53,000 --> 00:42:55,960
Speaker 2: has this crazy magnetic charge that makes it radiate a

912
00:42:56,000 --> 00:42:57,319
Speaker 2: lot as it flies through.

913
00:42:57,719 --> 00:42:59,640
Speaker 1: Wait, so you think it would also be massive. Why

914
00:42:59,680 --> 00:43:00,719
Speaker 1: do you think it would be massive?

915
00:43:00,760 --> 00:43:03,279
Speaker 2: There are lots of different theories for magnetic monopoles. Some

916
00:43:03,360 --> 00:43:05,080
Speaker 2: of them predicted it would be massive, some of them

917
00:43:05,120 --> 00:43:08,560
Speaker 2: predicted wouldn't be. Basically, this experiment can only see the

918
00:43:08,600 --> 00:43:11,359
Speaker 2: ones that are massive. If there's a magnetic monopole out

919
00:43:11,360 --> 00:43:13,400
Speaker 2: there that has very very low mass, then it wouldn't

920
00:43:13,400 --> 00:43:15,120
Speaker 2: make it through the ice, and so you wouldn't see

921
00:43:15,120 --> 00:43:15,759
Speaker 2: this signature.

922
00:43:15,880 --> 00:43:19,000
Speaker 1: So now I feel like this is just getting more

923
00:43:19,120 --> 00:43:22,160
Speaker 1: theoretical by the minute. So now you're assuming it exists,

924
00:43:22,160 --> 00:43:24,759
Speaker 1: and also that it's massive, and also that it has

925
00:43:24,800 --> 00:43:27,000
Speaker 1: a huge magnetic charge to it, and also.

926
00:43:26,920 --> 00:43:29,239
Speaker 2: That it's going super duper fast. We can only see

927
00:43:29,280 --> 00:43:32,480
Speaker 2: these things if they're moving like relativistically, right. Cherenkov light

928
00:43:32,560 --> 00:43:35,200
Speaker 2: is only emitted if the thing is moving faster than

929
00:43:35,280 --> 00:43:38,240
Speaker 2: photons through that material. If you have a slow massive monopole,

930
00:43:38,239 --> 00:43:40,800
Speaker 2: it wouldn't emit this light. We wouldn't see it. But

931
00:43:41,040 --> 00:43:44,680
Speaker 2: this telescope is capable of seeing massive monopoles with a

932
00:43:44,719 --> 00:43:48,000
Speaker 2: lot of magnetic charge if they're also moving faster than

933
00:43:48,000 --> 00:43:50,160
Speaker 2: three quarters of the speed of light. So you're right,

934
00:43:50,200 --> 00:43:52,160
Speaker 2: it can't look for every kind of monopole, but it's

935
00:43:52,160 --> 00:43:55,319
Speaker 2: definitely worth looking because if they are there, they would

936
00:43:55,360 --> 00:43:58,840
Speaker 2: be spectacular signature, would be like very obvious, very easy

937
00:43:58,880 --> 00:44:00,520
Speaker 2: to see it, and very hard to spoof.

938
00:44:00,640 --> 00:44:03,600
Speaker 1: But I guess, hasn't this observatory been out there for

939
00:44:03,640 --> 00:44:06,920
Speaker 1: a while. Wouldn't this have boundaries by now? Or no,

940
00:44:07,000 --> 00:44:08,240
Speaker 1: it is these weird streaks.

941
00:44:08,400 --> 00:44:10,160
Speaker 2: Yeah, you're right, it seems like it would be kind

942
00:44:10,160 --> 00:44:12,279
Speaker 2: of obvious in their data. Why wouldn't they have noticed it?

943
00:44:12,719 --> 00:44:14,760
Speaker 2: But you know, it's not like people are always looking

944
00:44:14,800 --> 00:44:17,320
Speaker 2: through the data by eye. When you do an analysis

945
00:44:17,320 --> 00:44:19,359
Speaker 2: of your data in a particle physics experiment, you're looking

946
00:44:19,360 --> 00:44:21,799
Speaker 2: for a particular kind of thing usually, and so this

947
00:44:21,920 --> 00:44:24,120
Speaker 2: might have been missed if nobody was looking for it.

948
00:44:24,440 --> 00:44:26,680
Speaker 2: So people went and did a dedicated search, like, let's

949
00:44:26,719 --> 00:44:28,520
Speaker 2: look through the data to see if there's any kind

950
00:44:28,520 --> 00:44:31,399
Speaker 2: of these weird things. So they've been running your life

951
00:44:31,400 --> 00:44:33,279
Speaker 2: for like almost a decade, and so they look through

952
00:44:33,320 --> 00:44:34,920
Speaker 2: all of their data trying to see if there are

953
00:44:34,920 --> 00:44:38,640
Speaker 2: any big, spectacular signatures of bright monopoles passing through this

954
00:44:38,760 --> 00:44:42,000
Speaker 2: cube of ice. And they didn't see any want.

955
00:44:41,800 --> 00:44:46,880
Speaker 1: Want wam, so all this setup was for nothing.

956
00:44:47,000 --> 00:44:49,480
Speaker 2: All this setup tells us that if there are monopoles

957
00:44:49,520 --> 00:44:52,200
Speaker 2: out there, they're either not moving fast, or they don't

958
00:44:52,200 --> 00:44:54,840
Speaker 2: have enough mass, or there's something very different from what

959
00:44:54,880 --> 00:44:58,120
Speaker 2: we expected. But it's pretty awesome to take this cube

960
00:44:58,120 --> 00:44:59,880
Speaker 2: of ice in the South Pole and to look for

961
00:45:00,040 --> 00:45:03,120
Speaker 2: these things. I love how dramatic the signature is. I

962
00:45:03,160 --> 00:45:05,279
Speaker 2: love how exciting it is. Because also they're going to

963
00:45:05,400 --> 00:45:07,759
Speaker 2: keep running it. It might be that monopoles are just

964
00:45:07,800 --> 00:45:10,759
Speaker 2: pretty rare, Maybe there aren't very many left over, Maybe

965
00:45:10,760 --> 00:45:13,200
Speaker 2: there weren't very many made in the Big Bang. Maybe

966
00:45:13,239 --> 00:45:15,880
Speaker 2: they're all clustered together the center of the galaxy. We

967
00:45:16,040 --> 00:45:18,520
Speaker 2: just don't know, so it's worthwhile to keep looking. So

968
00:45:18,520 --> 00:45:20,400
Speaker 2: they're going to keep running this experiment, and they're going

969
00:45:20,440 --> 00:45:22,640
Speaker 2: to keep looking for monopoles, and you know, it only

970
00:45:22,680 --> 00:45:27,520
Speaker 2: really takes one because it's such a dramatic and spectacular signature.

971
00:45:27,440 --> 00:45:29,359
Speaker 1: And it sounds I give you fine one. It would

972
00:45:29,360 --> 00:45:31,520
Speaker 1: be pretty significant, right, like you're just trying to prove

973
00:45:31,560 --> 00:45:33,000
Speaker 1: its existence exactly.

974
00:45:33,040 --> 00:45:35,040
Speaker 2: Just knowing that it's possible for them to exist would

975
00:45:35,040 --> 00:45:38,200
Speaker 2: be amazing game changing, right the same way that like

976
00:45:38,560 --> 00:45:42,880
Speaker 2: discovering one single particle of antimatter proved that antimatter is

977
00:45:42,920 --> 00:45:46,160
Speaker 2: a thing, and this symmetry exists in the universe, like

978
00:45:46,160 --> 00:45:48,640
Speaker 2: the guy got the Nobel Prize for literally a picture

979
00:45:48,680 --> 00:45:52,640
Speaker 2: of one particle that he found in nineteen twenty nine.

980
00:45:53,000 --> 00:45:55,480
Speaker 2: And so the discovery of a single monopole would tell

981
00:45:55,560 --> 00:45:58,319
Speaker 2: us something really deep about the nature of electricity and

982
00:45:58,440 --> 00:46:01,840
Speaker 2: magnetism in our universe. I would answer your question, like,

983
00:46:01,880 --> 00:46:04,799
Speaker 2: why is magnetism a thing, well, because magnetic monopoles are

984
00:46:04,840 --> 00:46:07,280
Speaker 2: part of our universe for the same reason the charges

985
00:46:07,320 --> 00:46:09,520
Speaker 2: are a thing, and so to me that would be

986
00:46:09,560 --> 00:46:12,200
Speaker 2: really fascinating and these things are totally worth looking. Every

987
00:46:12,239 --> 00:46:14,360
Speaker 2: time I hear about magnetic monopoles, I'm like, ooh, I

988
00:46:14,400 --> 00:46:15,239
Speaker 2: hope they found it.

989
00:46:16,040 --> 00:46:18,200
Speaker 1: I guess maybe a question you can ask is what

990
00:46:18,239 --> 00:46:20,640
Speaker 1: if they don't exist, what does that mean about the universe.

991
00:46:20,680 --> 00:46:24,160
Speaker 2: It means the universe is imbalanced in this weird, uncomfortable way.

992
00:46:24,360 --> 00:46:27,279
Speaker 2: We like symmetry in our equations, we like balance, We

993
00:46:27,440 --> 00:46:30,600
Speaker 2: like things to not prefer one direction or another. So

994
00:46:30,640 --> 00:46:34,120
Speaker 2: it's pretty weird if electricity and magnetism have this deep relationship,

995
00:46:34,280 --> 00:46:37,640
Speaker 2: but the universe prefers electricity for some reason. It's the

996
00:46:37,680 --> 00:46:40,359
Speaker 2: same as being uncomfortable about like why matter is matter

997
00:46:40,400 --> 00:46:44,160
Speaker 2: and antimatter is pretty rare. We'd like an explanation for that,

998
00:46:44,360 --> 00:46:46,680
Speaker 2: And so if there's a symmetry, then we don't need

999
00:46:46,680 --> 00:46:48,920
Speaker 2: an explanation. If there isn't a symmetry, then we need

1000
00:46:49,000 --> 00:46:49,760
Speaker 2: to know why.

1001
00:46:50,040 --> 00:46:52,480
Speaker 1: Well, it sort of sounds like, you know, generally you

1002
00:46:52,480 --> 00:46:56,839
Speaker 1: can explain magnetism. We just electric charge and spin or

1003
00:46:57,080 --> 00:46:59,799
Speaker 1: spin direction. I wonder you even need magnetism.

1004
00:47:00,760 --> 00:47:03,960
Speaker 2: Yeah, well that's why we combined electricity magnetism too one theory.

1005
00:47:04,400 --> 00:47:06,960
Speaker 2: So in that sense, is magnetism even really a thing? Well,

1006
00:47:07,000 --> 00:47:11,200
Speaker 2: electromagnetism is a thing, and so magnetism on its own

1007
00:47:11,360 --> 00:47:13,520
Speaker 2: doesn't really make sense. It's sort of like saying, you know,

1008
00:47:13,920 --> 00:47:16,800
Speaker 2: do you need elephant tails? Well, they're part of elephants

1009
00:47:16,800 --> 00:47:19,360
Speaker 2: that don't exist by themselves, but they're also an important

1010
00:47:19,400 --> 00:47:22,120
Speaker 2: part of the elephant, right, elephants don't want you chopping

1011
00:47:22,160 --> 00:47:22,839
Speaker 2: their tails off.

1012
00:47:23,000 --> 00:47:28,359
Speaker 1: I don't know, I haven't asked any elephants, and they

1013
00:47:28,440 --> 00:47:30,279
Speaker 1: need to be fine with their tails. I guess what

1014
00:47:30,320 --> 00:47:33,040
Speaker 1: I mean is maybe like a you know, like maybe

1015
00:47:33,280 --> 00:47:35,200
Speaker 1: our wonder if we're trying to look for an effect

1016
00:47:35,200 --> 00:47:37,560
Speaker 1: that we can already explain. Do you know what I mean?

1017
00:47:37,600 --> 00:47:40,560
Speaker 1: Like we have like a charge, we have spin. That

1018
00:47:40,840 --> 00:47:42,400
Speaker 1: kind of explains maganism, doesn't it.

1019
00:47:42,640 --> 00:47:45,439
Speaker 2: Yeah. Absolutely, we can explain all the phenomena we see

1020
00:47:45,480 --> 00:47:49,920
Speaker 2: in the universe without magnetic charges. But the explanation we

1021
00:47:50,000 --> 00:47:52,320
Speaker 2: build has this hole in it, which makes us wonder

1022
00:47:52,320 --> 00:47:54,560
Speaker 2: if we're missing something, the same way that when we

1023
00:47:54,600 --> 00:47:57,080
Speaker 2: put the periodic table together, we notice there's some holes

1024
00:47:57,080 --> 00:47:59,120
Speaker 2: in it. There's some gaps in there. I wonder if

1025
00:47:59,120 --> 00:48:01,239
Speaker 2: that kind of thing exist. Let's go out and try

1026
00:48:01,280 --> 00:48:05,239
Speaker 2: to make technetium. Oh, look, it does exist. That feels satisfactory. Right,

1027
00:48:05,280 --> 00:48:08,320
Speaker 2: It's like an OCD person filling in that last square.

1028
00:48:08,400 --> 00:48:11,560
Speaker 2: So the structure of the theory of electromagnetism seems so

1029
00:48:11,680 --> 00:48:15,799
Speaker 2: tantalizing and tempting it suggests that they might exist. So

1030
00:48:15,840 --> 00:48:18,080
Speaker 2: you're right, we don't need them to explain anything we've

1031
00:48:18,120 --> 00:48:19,880
Speaker 2: seen in the universe. In fact, we have to go

1032
00:48:19,920 --> 00:48:22,760
Speaker 2: out and make special experiments, just a hunt for effects.

1033
00:48:22,800 --> 00:48:26,120
Speaker 2: They can't be explained with electric charges. But we'd love

1034
00:48:26,160 --> 00:48:27,880
Speaker 2: if they did exist because it would just make the

1035
00:48:27,880 --> 00:48:29,520
Speaker 2: theory more beautiful and balanced.

1036
00:48:29,719 --> 00:48:32,520
Speaker 1: And that's what physics. It's all about beauty and balance.

1037
00:48:32,760 --> 00:48:35,920
Speaker 2: It's about finding simple explanations for the complex phenomena.

1038
00:48:36,000 --> 00:48:38,479
Speaker 1: Yeah, all right, well, good luck to the ice cubed

1039
00:48:38,520 --> 00:48:42,279
Speaker 1: nutrino experiment. I hope they find a monopole or a

1040
00:48:42,320 --> 00:48:45,640
Speaker 1: fast moving heavy monopole, right, but those are the requirements,

1041
00:48:45,920 --> 00:48:48,440
Speaker 1: a highly magnetic, fast massive monopole.

1042
00:48:48,560 --> 00:48:50,200
Speaker 2: And if they do, I hope they invite you down

1043
00:48:50,200 --> 00:48:51,360
Speaker 2: there to help them celebrate.

1044
00:48:51,560 --> 00:48:54,919
Speaker 1: Oh man, for sure, in fact, invite me now, I'll

1045
00:48:54,960 --> 00:48:58,440
Speaker 1: totally go. I'll help you dig one of the one

1046
00:48:58,440 --> 00:48:58,839
Speaker 1: of the holes.

1047
00:48:58,880 --> 00:48:59,839
Speaker 2: All right, put that on your tour.

1048
00:49:00,400 --> 00:49:03,319
Speaker 1: Sounds good. Well, we hope you enjoyed that. Thanks for

1049
00:49:03,400 --> 00:49:04,719
Speaker 1: joining us, see you next time.

1050
00:49:12,440 --> 00:49:15,240
Speaker 2: Thanks for listening, and remember that Daniel and Jorge Explain

1051
00:49:15,320 --> 00:49:19,319
Speaker 2: the Universe is a production of iHeartRadio. For more podcasts

1052
00:49:19,320 --> 00:49:23,960
Speaker 2: from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever

1053
00:49:24,040 --> 00:49:25,760
Speaker 2: you listen to your favorite shows.