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Speaker 1: Hey, Katie, how do your particles feel today? I guess

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Speaker 1: it depends on which particle you ask. All right, well,

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Speaker 1: let's start with your protons. How are they feeling this morning?

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Speaker 1: They're feeling pretty positive. And your electrons any negativity there? Well,

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Speaker 1: I would say they're all charged up. And what about

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Speaker 1: those neutrons. We don't want to overlook them? How are

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Speaker 1: they doing? There? Come scums? All right, well, let's see

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Speaker 1: if this podcast can get them excited. Well, I'm excited

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Speaker 1: even if my neutrons are kind of just meth. Hello.

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Speaker 1: I'm Daniel. I'm a particle of physicist and a professor

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Speaker 1: at UC Irvine, and I contain multitudes of particles. And

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Speaker 1: I am Katie Golden. I host the podcast Creature feature

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Speaker 1: about animals and my particles. Uh, I think I've got

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Speaker 1: at least ten of them. You know, really, your podcast

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Speaker 1: is also about particles, since all animals are also made

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Speaker 1: of particles. That's right, So who's the physicist? Now? We're

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Speaker 1: all physicists. That's the point. Every podcast is really about particles,

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Speaker 1: even those true crime podcasts, even the Bigfoot podcast, even

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Speaker 1: those paranormal e sp podcasts that consistently outrank ours in

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Speaker 1: the natural science category, but welcome to the podcast. Daniel

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Speaker 1: and Jorge explain the universe in which we treat the

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Speaker 1: entire universe as a crazy swarm of particles. Particles that

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Speaker 1: are mysterious, particles that are weird, particles that follow very

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Speaker 1: strange quantum rules, but particles that do follow rules in

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Speaker 1: the end, rules that we think we can understand, we

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Speaker 1: can digest, that we can explain to you. On this podcast,

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Speaker 1: we hope to wrap our minds around everything in the universe,

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Speaker 1: break it down to its time little particles, and feed

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Speaker 1: them to you one by one. My co host and friend,

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Speaker 1: Jorge Champ can't be here today, but we are very

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Speaker 1: lucky to have our regular co host, Katie. Katie thanks

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Speaker 1: a lot for joining us. Of course, I am ready

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Speaker 1: to learn about particles because you know, they seem important,

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Speaker 1: given that I need them in me to make me, me,

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Speaker 1: to make you you. Indeed, but you know what is

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Speaker 1: the units of you? Diving right into the philosophical questions

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Speaker 1: at the heart of particle physics, one thing we have

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Speaker 1: learned recently about particles and the universe is that we

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Speaker 1: all seem to be made up of the same kinds

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Speaker 1: of particles. I'm made of protons, neutrons, and electrons. You're

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Speaker 1: made of protons, neutrons and electrons. What's the difference? Are

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Speaker 1: there Katie particles and Daniel particles? No, it turns out

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Speaker 1: that the only different it's between Daniel and Katie fundamentally,

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Speaker 1: or between an apple and a banana, or between kittens

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Speaker 1: and lava, is how those particles are put together. You

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Speaker 1: take that same basic set of building box and you

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Speaker 1: can make anything. You're blowing my mind. So if we

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Speaker 1: sort of melted down Katie and Daniel into just the

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Speaker 1: particles and then rearranged all the Katie particles into Daniel

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Speaker 1: particle like the Daniel blueprints, then now would just create

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Speaker 1: a Daniel even though uh, those were originally my particles.

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Speaker 1: That's exactly right. It seems like our universe follows the

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Speaker 1: same principles as legos, that the same basic building blox

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Speaker 1: can be used to make anything. Right, if your little

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Speaker 1: brother used your legos to make a huge dinosaur and

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Speaker 1: then you smashed it and used it to build a

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Speaker 1: pirate boat, you could reuse those dinosaur legos to make

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Speaker 1: your pirate hip. Now Here, of course, I have to

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Speaker 1: quibble with the fundamental flaw of Lego toys. The original Legos,

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Speaker 1: We're just the basic building blocks, and I love that

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Speaker 1: simplicity that I had no bias to them. You you

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Speaker 1: could use them to make anything. These fancy new modern Legos,

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Speaker 1: you know, they come with stuff printed on the sides

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Speaker 1: or specific shapes, right, so the sort of like predetermine

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Speaker 1: what you have to build. I'm talking about the true

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Speaker 1: original Legos. Yeah. I usually just built the tallest tower

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Speaker 1: I could make out of my Legos, and then usually

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Speaker 1: put a bunch of guys on it, so it's like

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Speaker 1: just this big tower of Babel. I don't know what

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Speaker 1: that says about me, but yeah, I agree, Although I

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Speaker 1: do like that modern legos do have different kinds of Legos.

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Speaker 1: Like it started out, I think, with just the one

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Speaker 1: Lego block unit, but now you have all sorts of

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Speaker 1: different types of Legos. You have like the sort of

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Speaker 1: o G blocks, but you also have these long, skinny ones,

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Speaker 1: you have ones that can rotate, you have like connector legos.

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Speaker 1: But is that at all similar to how the universe works?

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Speaker 1: Seems to be very similar to how the universe works.

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Speaker 1: You know, I'm made of protons and neutrons and electrons

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Speaker 1: and store are you and so is basically everything that

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Speaker 1: you've ever eaten, everything you've ever tripped over, everything you've

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Speaker 1: ever thrown at your sibling. They're all made of the

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Speaker 1: same ingredients. And if you look at the periodic table,

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Speaker 1: you can see that that's true, right, Every element on

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Speaker 1: the periodic table is just made of protons and neutrons

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Speaker 1: and electrons arranged in different numbers. You start with one

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Speaker 1: proton and electron, you have hydrogen. You added another proton,

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Speaker 1: you get helium. Keep adding protons, do you get different elements?

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Speaker 1: You're just adding more of the same basic building blocks,

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Speaker 1: but you make fundamentally different elements. But those different elements

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Speaker 1: are not really fundamentally different. The only difference between carbon

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Speaker 1: and neon, or between lead and gold is the number

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Speaker 1: of protons inside those nuclei. So really you can build

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Speaker 1: anything with the same basic building blocks. It's so hard

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Speaker 1: to wrap my head around that. So, you know, just

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Speaker 1: like it's just seems that it's a numbers game, because

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Speaker 1: like usually with legos, if you just have like five legos,

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Speaker 1: it doesn't suddenly turn into from like you know, a

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Speaker 1: sugar into like gold or something like that. But with

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Speaker 1: these on the atomic levels. When you change just the

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Speaker 1: number of these these tiny particles, it turns from you know,

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Speaker 1: something that if you eat nothing would happen to you,

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Speaker 1: to something if you eat it it would be bad

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Speaker 1: and drive you crazy, like eating lead versus drinking air.

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Speaker 1: I guess we don't really drink air, but you get

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Speaker 1: the idea. Yeah. Absolutely. It might seem like a small difference.

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Speaker 1: You're just adding a proton, what's the big deal, But

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Speaker 1: it completely changes its emergent behavior. All these characteristics that

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Speaker 1: were familiar with the way metals are shiny and conduct electricity,

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Speaker 1: the way some of these elements are float around and

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Speaker 1: ignore the other ones that are not very active. All

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Speaker 1: of those properties are determined by how many protons and

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Speaker 1: how many electrons there are in each atom, and so like,

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Speaker 1: the fact that metals are metallic and conductive comes from

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Speaker 1: the fact that their electron shells are not filled, which

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Speaker 1: is determined by the number of protons inside the nucleus.

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Speaker 1: So it's not just an relevant detail, it's a totally

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Speaker 1: determining fact. But it's fascinating they're all made out of

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Speaker 1: the same bits. The other fascinating thing to me is

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Speaker 1: that we're all made out of roughly the same ratios

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Speaker 1: of bits, Like any given atom has basically a one

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Speaker 1: to one to one proton to neutron to electron ratio.

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Speaker 1: So lead has more protons than hydrogen, but it also

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Speaker 1: has more neutrons and also has more electrons. That means

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Speaker 1: that not only are we all made out of the

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Speaker 1: same three basic building blocks, but we're made out of

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Speaker 1: them in the same proportions. It's not like Katie has

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Speaker 1: more electrons and Daniel has more protons, right, where the

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Speaker 1: same building blocks in the same proportions just rearranged differently.

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Speaker 1: So you you mentioned that the number of protons sort

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Speaker 1: of changes the element. In the number of electrons, it's

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Speaker 1: kind of changes the characteristic of these elements, But you

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Speaker 1: didn't mention neutrons too much being sort of the determinant

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Speaker 1: of what these elements are. Why are neutrons different in

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Speaker 1: terms of pro tons and electrons. Yeah, it's a good point,

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Speaker 1: and neutrons are sadly often overlooked, which is why we

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Speaker 1: are dedicating almost our entire podcast today to talking about

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Speaker 1: these mysterious, funny particles. But you're right that neutrons don't

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Speaker 1: really determine as much the identity of the atom, and

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Speaker 1: that's because they are electrically neutral. Like if you add

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Speaker 1: another proton to the atom, then in order to make

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Speaker 1: it electrically neutral, you have to add another electron in

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Speaker 1: orbit around it, and that really changes the chemical properties.

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Speaker 1: It changes how this thing interacts, whether or not it's

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Speaker 1: electron orbitals are filled, or whether it's got an opening

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Speaker 1: that very strongly affects the behavior of the atom. You

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Speaker 1: add another neutron, then you don't need to add another electron.

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Speaker 1: So you can add neutrons, no big deal. You can't

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Speaker 1: just add neutrons anytime you like to any atom. It

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Speaker 1: doesn't make them heavier, and it makes these other versions

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Speaker 1: of the elements. These are called isotopes. So, for example,

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Speaker 1: you can have hydrogen, which is just a proton, but

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Speaker 1: you can also have deuterium, which is a proton and

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Speaker 1: a neutron. So you put those together inside the nucleus,

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Speaker 1: you have an electron around it. It's still called hydrogen,

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Speaker 1: but it's like a heavy version of hydrogen. For example,

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Speaker 1: if you put that together into H two O, but

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Speaker 1: instead of the hydrogen, you have this heavy version of

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Speaker 1: hydrogen with a neutron also in the nucleus. Then you

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Speaker 1: get what's called heavy water, which we sometimes use in

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Speaker 1: nuclear experiments. Right, so it does change a little bit

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Speaker 1: sort of the flavor of the element to add neutron,

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Speaker 1: sort to take them away, but it doesn't change its

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Speaker 1: fundamental identity, which is determined by the charged objects of

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Speaker 1: proton and the electron. So that's really interesting to me.

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Speaker 1: Why is the neutron involved at all in the atomic

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Speaker 1: structure if it's just kind of this It seems like

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Speaker 1: this neutral fluff particle just this like dead weight, But

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Speaker 1: is that really true. No, the neutron often overlooked, but

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Speaker 1: it does play a vital role in keeping the nucleus together.

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Speaker 1: We're gonna dig into it a bit more on the podcast,

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Speaker 1: but very briefly, think about how the nucleus stays together. Right,

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Speaker 1: If you have the nucleus of an atom that has

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Speaker 1: like twenty five protons in it, those things are all

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Speaker 1: positive of lee charged. Why don't they just like bust apart?

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Speaker 1: You know, why don't they repel each other because they

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Speaker 1: all have the same positive charge. The answer is that

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Speaker 1: the nucleus is held together by the strong force, which

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Speaker 1: is much more powerful than electromagnetism and neutrons. Even though

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Speaker 1: they are neutral electromagnetically, they do involve the strong force.

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Speaker 1: Turns out, the nucleus is a bit of a delicate

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Speaker 1: puzzle keeping those protons from flying apart. You need the neutrons.

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Speaker 1: It's a little bit of a spacer, and so it's

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Speaker 1: easier to make stable nuclei if you include the neutrons.

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Speaker 1: I see, So without the neutrons, the protons would not

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Speaker 1: be able to stand each other's presence. I know people

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Speaker 1: like that and like in group dynamics, that kind of

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Speaker 1: keep the peace. So that's that is really interesting. So

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Speaker 1: I guess without neutrons we wouldn't exist, we would not

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Speaker 1: be held together. But it's odd to me though, that

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Speaker 1: that neutrons have. It seems like they're fundamentally different from

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Speaker 1: like a proton or an election because they don't have

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Speaker 1: this charge. So you know, how did that even really happen? Yeah, well,

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Speaker 1: these are deep questions about the universe, like why do

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Speaker 1: we have neutrons anyway? Right, it's just sort of how

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Speaker 1: the universe coalesces. Remember, we go back to the very

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Speaker 1: early part of the universe where everything is just energy,

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Speaker 1: and the universe then expands and cools and as it cools.

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Speaker 1: It's sort of like crystallizes into lower energy states. Things

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Speaker 1: sort of like come together and form stable particles. And

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Speaker 1: by looking around in the universe and seeing sort of

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Speaker 1: what was made, we can tell sort of like what

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Speaker 1: the options were. We don't know like why it's possible

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Speaker 1: to build neutrons necessarily, but we see that a lot

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Speaker 1: of them sort of emerged from the chaos of the

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Speaker 1: early universe. And that's another really fascinating aspect of these

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Speaker 1: particles is their age. Like protons, we think that protons

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Speaker 1: probably live forever. Like you make a proton, you can

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Speaker 1: just hang out forever and stick around till the end

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Speaker 1: of time. Same with an electron. Electron is stable, right,

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Speaker 1: you have an electron sitting in empty space, it will

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Speaker 1: just stay an electron for a billion years, maybe a

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Speaker 1: trillion years, a quadrillion years. And what that means is

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Speaker 1: that the protons and electrons inside your body were probably

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Speaker 1: made during the Big Bang. So you are made of

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Speaker 1: ancient multitudes. I mean, you know, thank you for that,

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Speaker 1: thank you for calling me old. So neutrons weren't necessarily

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Speaker 1: made during the Big Bang. You're saying, so neutrons were

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Speaker 1: also made during the Big bang, right as the universe cooled,

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Speaker 1: we got protons, we've got electrons, we've got neutrons. But

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Speaker 1: there's a difference between protons, electrons, and neutrons that goes

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Speaker 1: beyond just their electric charge. Neutrons don't seem to last

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Speaker 1: forever the same way that protons and electrons do. In fact,

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Speaker 1: they don't last very long at all. So that makes

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Speaker 1: them fundamentally weird and different. And by studying the details

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Speaker 1: of how long the neutron lives and what it turns into,

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Speaker 1: we might get some clues to these questions about like

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Speaker 1: why are there neutrons after all? What's going on inside

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Speaker 1: the neutrons? Are they irrelevant little particles? Are they the

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Speaker 1: most important clue we have to the nature of the universe?

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Speaker 1: So yeah, no, I'm really curious, like what does it

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Speaker 1: mean for a neutron to be alive? And then how

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Speaker 1: does it die? And how long does that process take?

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Speaker 1: And so today on the podcast we'll be answering the

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Speaker 1: question how long does a neutron live? Alright, Katie, and

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Speaker 1: you've already called me out, I see for using the

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Speaker 1: word live in the title, because our neutrons alive after all,

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Speaker 1: and you know, as a particle physicist, I think about

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Speaker 1: these particles as sort of having a lifetime. But you're right,

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Speaker 1: neutrons are not alive, nor are they dead in any

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Speaker 1: sort of biological sense. I mean, if you corner a

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Speaker 1: biologist and try to get them to answer the question

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Speaker 1: what is life, They're gonna start sweating and giving you

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Speaker 1: a really complex answer. So it's not a simple question.

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Speaker 1: But but no, I get it. So it's like a

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Speaker 1: neutron does not always remain a neutron in the sense

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Speaker 1: that it does not stay the same forever, and so

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Speaker 1: that could be seen as it, you know, essentially decaying

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Speaker 1: or dying. Right exactly, When we talk about particle lifetimes,

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Speaker 1: we're talking about how long the particle exists before it

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Speaker 1: turns into something else. So some particles in the universe

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Speaker 1: are stable, like electrons and protons and the corks that

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Speaker 1: make up those protons and photons. For example, you can

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Speaker 1: create a photon with a flashlight, shoot it out into space,

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Speaker 1: and it might fly for billions or trillions of years.

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Speaker 1: Some of the photons received by your eyeballs when you

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Speaker 1: look up at night have been crawling across the universe

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Speaker 1: for billions of years. It's incredible how long they have survived.

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Speaker 1: So some particles sort of live forever. And again we're

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Speaker 1: using to live in a sort of anthropomorphic biological analogy

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Speaker 1: to life. Really we just mean exists, but other particles don't.

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Speaker 1: Other particles are not stable, and the neutron is one

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Speaker 1: of those. That's really interesting. So yeah, I didn't really

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Speaker 1: think of neutrons as being an impermanent thing. I think

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Speaker 1: about the building blocks of life. I mean I pictured

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Speaker 1: them as these like little permanent speares that you know,

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Speaker 1: make everything and just stay the same, and you know

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Speaker 1: that is just this kind of like solid foundation to everything.

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Speaker 1: But now you're shaking that all up. What if I

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Speaker 1: told you that one of your legos a specific kind

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Speaker 1: of lego, if you didn't use it, it would just

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Speaker 1: like evaporate or turn into other kinds of legos. That

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Speaker 1: sounds like an excuse a little brother would give when

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Speaker 1: you're stealing all my legos. All right, but this is

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Speaker 1: not a family therapy podcast, at least not yet. So

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Speaker 1: I was curious if other people had thought about the

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Speaker 1: lifetime of the neutron, if people were aware that neutrons

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Speaker 1: don't live forever, and how long they thought it might live.

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Speaker 1: So I went out there to our cadre of Internet

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Speaker 1: volunteers who are willing to answer hard physics questions without

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Speaker 1: any opportunity to prepare themselves. Thank you very much, and

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Speaker 1: if you would like to join this hearty group, then please,

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Speaker 1: they'll be shy right to me. Two questions at Daniel

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Speaker 1: and Jorge dot com. So think about it for a moment.

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Speaker 1: Do you know how long a neutron lives? Here's what

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Speaker 1: people had to say. I guess. My guess would be

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Speaker 1: that it would live indefinitely until some other force overpowers

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Speaker 1: the forces that hold it together. Tron lives um like

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Speaker 1: a free nel tron shouldn't been that long, but I

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Speaker 1: don't know, probably not more than a few minutes. I

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Speaker 1: think that actually this is something that's really confused me

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Speaker 1: as I've started to look into and tried to understand

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Speaker 1: particle physics and quantum physics and everything, and I think

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Speaker 1: that possibly it's just an instant. Yeah, neutrons, just like

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Speaker 1: like a lot of particles, just exists for an instant.

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Speaker 1: On the other hand, it could be they could last

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Speaker 1: for by entire lifetime, so yeah, it could be a

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Speaker 1: long time as well. Well. Neutrons makeup part of stomic nuclei,

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Speaker 1: so they live for at least as long as the

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Speaker 1: longest lived elements UM, so at least a few million years.

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Speaker 1: But I think UH universe skills tend to be quite extreme,

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Speaker 1: so I guess since they don't live for only fractions

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Speaker 1: of a millisecond, I'm going to guess they live for

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Speaker 1: billions of years. I don't know if a neutron lives forever,

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Speaker 1: and I think the answer to that question is we

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Speaker 1: don't know if neutrons live forever. I know that proton

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Speaker 1: decay is still actively being studied and debated, and I

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Speaker 1: don't think a neutron would be much different. And as

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Speaker 1: of now, I believe we do not know how long

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Speaker 1: they live or if they decay away. I know that

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Speaker 1: protons decay inter neutrons UM because they emit a positron,

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Speaker 1: so I'm gonna wonder whether neutrons can also emit an

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Speaker 1: electron and in a sense decay into protons. But this

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Speaker 1: process doesn't happen, so all the proton has a lifetime

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Speaker 1: of I don't know if the order of a few

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Speaker 1: seconds UM, and you'tron. I know it's a number of

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Speaker 1: years and I think it's the amount amount of time

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Speaker 1: is comfortable to the age of the universe something like that.

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Speaker 1: I really like the answer, probably just an instant, or

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Speaker 1: maybe my entire lifetime, because even though that seems funny,

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Speaker 1: like how could you compare an instant to an entire lifetime?

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Speaker 1: How could you be so equivocal? On the universal scale,

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Speaker 1: those are almost the same in a certain way, right,

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Speaker 1: Like when you look at the entire lifetime of the universe,

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Speaker 1: an instant in one human lifetime or not that different exactly.

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Speaker 1: And that's the incredible thing about all of these numbers

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Speaker 1: in physics that when you're talking about how long something lives,

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Speaker 1: it could be some crazy, tiny tiny number ten to

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Speaker 1: the minus twenty seconds, or it could be cosmic the

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Speaker 1: scale of the lifetime of the universe, right, which is like,

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Speaker 1: you know, six tillions of seconds, and so it's hard

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Speaker 1: to know, like on that huge scale where to put

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Speaker 1: these numbers, And so if you don't have any information,

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Speaker 1: then you're right, his entire lifetime does feel sort of

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Speaker 1: like an instant. And that's one of my favorite things

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Speaker 1: about physics that it may think about these cosmic sweeps

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Speaker 1: of time and recognize the fact that something that might

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Speaker 1: take our entire lifetime is basically meaningless on the time

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Speaker 1: scale of the universe. Well, way to make me feel

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Speaker 1: both old and small. So in terms of neutrons, like

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Speaker 1: it is interesting, like if they live like a human lifetime,

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Speaker 1: that makes me feel a little less alone, or if

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Speaker 1: they live like an instant, that almost makes me feel

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Speaker 1: sorry for them. It's really hard not to anthropomorphize something

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Speaker 1: once we're talking about how long it lasts, as if

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Speaker 1: the neutron particularly cares. But I guess I want to know, like,

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Speaker 1: what what is the neutron? Should I feel sorry for it? Well,

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Speaker 1: I'm not going to tell you how to feel about

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Speaker 1: the particles, but I'm happy to tell you how they're

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Speaker 1: put together and what they mean. And so in the

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Speaker 1: case of a neutron, we've been talking about it as

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Speaker 1: if it was a particle in itself, like atoms. We

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Speaker 1: said are made out of protons and neutrons in the

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Speaker 1: nucleus surrounded by electrons. And that's true, but we can

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Speaker 1: also drill one step deeper to understand what is the

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Speaker 1: neutron itself made out of? Now, in the case of

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Speaker 1: some fundamental particles like the electron, we don't know if

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Speaker 1: they're actually fundamental or made out of even smaller lego

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Speaker 1: building blocks. So far, the electron just looks like it's

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Speaker 1: only made out of itself, but that might just be

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Speaker 1: because we haven't zoomed in far enough. We don't have

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Speaker 1: colliders capable of blowing up electrons and seeing what's inside them.

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Speaker 1: In the case of protons and neutrons, we actually have

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Speaker 1: been able to break them up and see what's inside.

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Speaker 1: For about the last fifty years or so, we have

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Speaker 1: had colliders capable of smashing these particles and showing us

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Speaker 1: what they are made out of. And fascinatingly, the proton

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Speaker 1: and the neutron are made out of the same two

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Speaker 1: building blocks, up quarks and down corks, so there are

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Speaker 1: two funny little particles. They have weird fractional electric charges,

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Speaker 1: which allows them to get added up to make a

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Speaker 1: neutron or a proton. So, for example, a neutron is

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Speaker 1: an up cork which is charged two thirds, and then

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Speaker 1: two down corks, each of which are charged minus one third.

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Speaker 1: So neutron is an up, down, down Three of these

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Speaker 1: corks put together, and you get zero electric charge. So physicists,

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Speaker 1: when you're asked what's up cork? Do you just say

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Speaker 1: not much what's up cork with you? Or do you

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Speaker 1: have an actual answer to what's an up cork? And

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Speaker 1: I guess what's a down cork? I don't know what's

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Speaker 1: up is down, what's down is up? Sometimes in physics,

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Speaker 1: you know, as I always say, I'm not going to

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Speaker 1: be held responsible for the names of these particles, but

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Speaker 1: you know, there are some reasons why we called them

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Speaker 1: up corks and down corks. They're organized together by the

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Speaker 1: weak force into this pair, this up and down pair

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Speaker 1: that get linked together by the w boson, which we're

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Speaker 1: going to talk about in just a minute. But actually

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Speaker 1: in the nucleus, the upcorks and down corks are not

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Speaker 1: held together by the weak force. They're held together by

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Speaker 1: the strong force. So quarks have electric charges, but that's

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Speaker 1: not what's holding them together. Like you think about the

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Speaker 1: way molecules are held together, they're held together because of

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Speaker 1: the electric charges. These electrons are like whizzing around and

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Speaker 1: making these ionic bonds or covalent bonds. The electric charges

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Speaker 1: are basically irrelevant once you get inside the proton and

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Speaker 1: the neutron because there's a much more powerful force at play.

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Speaker 1: And that's the strong nuclear force, which totally overwhelms the

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Speaker 1: electromagnetic force, is able to hold all of these particles together.

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Speaker 1: And the strong nuclear force does that by using gluons.

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Speaker 1: So your mental picture of a neutron shouldn't be like

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Speaker 1: three little lego pieces that clicked neatly together and that's it. Instead,

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Speaker 1: it's more like three tiny little dots surrounded by a

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Speaker 1: swarm of these gluons that are holding it together. So

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Speaker 1: it's more like a bag of gluons with three hard

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Speaker 1: dots in it. So, oh my gosh, so gluons. It's

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Speaker 1: just this sort of like swarm of these things that

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Speaker 1: hold together the up quarks and down corks. So like,

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Speaker 1: the more we split things apart and try to think

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Speaker 1: about like the even smaller thing that holds the smaller

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Speaker 1: things together, it gets really difficult for my brain not

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Speaker 1: to start hurting. But all right, So, so do we

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Speaker 1: know like how many gluons are in a neutron or

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Speaker 1: is it just kind of this mass of stuff that

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Speaker 1: we know holds together of corks and down corks, But

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Speaker 1: we can't necessarily quantify how many of these things there are. Yeah,

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Speaker 1: that is a great question because probably you're wanting to

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Speaker 1: put together a model of what's going on inside the

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Speaker 1: neutron that has like a basic recipe, and those things

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Speaker 1: clicked together to make a neutron way like pieces of

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Speaker 1: a jigsaw puzzle get clicked together to make a bigger picture. Right,

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Speaker 1: But that's not really the way we think about these gluons.

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Speaker 1: Luans in this case are force particles. They're not matter particles.

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Speaker 1: What that means is that they don't really exist in

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Speaker 1: the same way that the matter particles do. They exist

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Speaker 1: as a representation of the force between the matter particles.

427
00:23:53,720 --> 00:23:56,000
Speaker 1: So you have the up cork and the two down corks.

428
00:23:56,000 --> 00:23:58,240
Speaker 1: They're sitting there and they're pulling on each other, the

429
00:23:58,280 --> 00:24:00,840
Speaker 1: strong forces holding them together there. How do you think

430
00:24:00,880 --> 00:24:03,119
Speaker 1: about that force, Well, there's a few different ways of

431
00:24:03,160 --> 00:24:05,840
Speaker 1: doing it. One is to think about them exchanging particles

432
00:24:05,840 --> 00:24:09,199
Speaker 1: like zooming gluons back together. That's how they hold themselves together.

433
00:24:09,680 --> 00:24:12,320
Speaker 1: And you can use that same strategy to think about

434
00:24:12,400 --> 00:24:15,280
Speaker 1: how other particles talk to each other, Like what happens

435
00:24:15,320 --> 00:24:17,840
Speaker 1: when two electrons push against each other because they have

436
00:24:17,920 --> 00:24:21,359
Speaker 1: the same electric charge. How does that actually work microscopically, Well,

437
00:24:21,400 --> 00:24:24,080
Speaker 1: you can think of them as shooting photons towards each

438
00:24:24,119 --> 00:24:28,320
Speaker 1: other because photons are the force particle for the electromagnetic force.

439
00:24:28,800 --> 00:24:31,640
Speaker 1: So inside the neutron, these corks are holding onto each

440
00:24:31,640 --> 00:24:34,800
Speaker 1: other by shooting gluons at each other. That's one way

441
00:24:34,800 --> 00:24:38,520
Speaker 1: of thinking about how the forces are working inside the neutron.

442
00:24:38,800 --> 00:24:41,000
Speaker 1: There's another way of thinking about it, which doesn't use

443
00:24:41,040 --> 00:24:43,840
Speaker 1: this sort of like virtual particles, these gluons sipping back

444
00:24:43,880 --> 00:24:46,480
Speaker 1: and forth. You just think about fields. Like if you're

445
00:24:46,520 --> 00:24:49,080
Speaker 1: more comfortable thinking about an electron being surrounded by its

446
00:24:49,119 --> 00:24:51,520
Speaker 1: electric field and the way that it pushes on other

447
00:24:51,560 --> 00:24:54,480
Speaker 1: electrons is that it's electric field pushes on it, then

448
00:24:54,520 --> 00:24:56,600
Speaker 1: you can think about the interior of the neutron that

449
00:24:56,680 --> 00:24:59,520
Speaker 1: same way as having three quarks each surrounded by a

450
00:24:59,640 --> 00:25:02,959
Speaker 1: field from the strong force, and those fields are tugging

451
00:25:02,960 --> 00:25:05,919
Speaker 1: on each other. Those are gluonic fields. You can think

452
00:25:05,960 --> 00:25:08,360
Speaker 1: about them as either like a huge tower or virtual

453
00:25:08,359 --> 00:25:11,159
Speaker 1: gluons which appear and disappear very quickly, or you can

454
00:25:11,200 --> 00:25:13,800
Speaker 1: think about them in terms of fields. Are two equivalent

455
00:25:13,920 --> 00:25:17,320
Speaker 1: mental pictures for the same fundamental process that's going on.

456
00:25:17,600 --> 00:25:19,800
Speaker 1: But you can't really like count the number of gluons

457
00:25:19,960 --> 00:25:22,200
Speaker 1: because they're not particles that exist in the same way

458
00:25:22,280 --> 00:25:25,440
Speaker 1: as the corks. So, Okay, in my recipe that I'm

459
00:25:25,480 --> 00:25:29,240
Speaker 1: writing for home baked neutrons, I'm just gonna put down

460
00:25:29,280 --> 00:25:34,440
Speaker 1: a pinch of gluons. So you said that this is

461
00:25:34,480 --> 00:25:39,600
Speaker 1: these are strong, uh, strong forces holding this neutron together.

462
00:25:39,960 --> 00:25:43,560
Speaker 1: But we were just talking about how maybe these neutrons

463
00:25:43,880 --> 00:25:46,600
Speaker 1: break apart. So how would they break apart if you

464
00:25:46,640 --> 00:25:49,760
Speaker 1: have these really strong forces holding them together? Great question,

465
00:25:49,800 --> 00:25:51,439
Speaker 1: and it reveals something about the way I think a

466
00:25:51,440 --> 00:25:54,439
Speaker 1: lot of people think about particles and their decay. What

467
00:25:54,560 --> 00:25:58,119
Speaker 1: happens when a particle decays? Is it breaking apart? Are

468
00:25:58,119 --> 00:26:00,520
Speaker 1: you taking its pieces and they're reassembling them to build

469
00:26:00,600 --> 00:26:04,639
Speaker 1: something else? Right, Well, what's happening when a neutron decays

470
00:26:04,760 --> 00:26:07,440
Speaker 1: is not actually that is breaking apart at all. It's

471
00:26:07,480 --> 00:26:10,920
Speaker 1: that one piece of its internal structure, one of those corks,

472
00:26:11,280 --> 00:26:15,800
Speaker 1: changes its nature. So remember that a neutron is up, down,

473
00:26:15,880 --> 00:26:18,680
Speaker 1: down right tow down corks and an up cork. Well,

474
00:26:18,680 --> 00:26:22,400
Speaker 1: what happens if one of those down corks changes its

475
00:26:22,400 --> 00:26:25,680
Speaker 1: flavor and becomes an up cork? Then you have two

476
00:26:25,760 --> 00:26:28,720
Speaker 1: upcorks in a down instead of two down corks and

477
00:26:28,800 --> 00:26:31,640
Speaker 1: an up. Remember that up coorks are charged plus two

478
00:26:31,800 --> 00:26:35,000
Speaker 1: thirds and a down cork is charged minus one third,

479
00:26:35,320 --> 00:26:37,800
Speaker 1: So now you have plus two third plus two third

480
00:26:38,280 --> 00:26:40,840
Speaker 1: minus one third gives you a charge of plus one.

481
00:26:41,320 --> 00:26:44,920
Speaker 1: That's a proton. So what happens when a neutron decays

482
00:26:45,480 --> 00:26:48,240
Speaker 1: is that one of its down corks converts into an

483
00:26:48,320 --> 00:26:51,920
Speaker 1: upcork and the neutron becomes a proton. So it doesn't

484
00:26:51,960 --> 00:26:54,720
Speaker 1: break apart. It flips from being a neutron to being

485
00:26:54,760 --> 00:26:58,040
Speaker 1: a proton. That's amazing. So it's less of a death

486
00:26:58,200 --> 00:27:00,720
Speaker 1: of a particle in more of a tram information of

487
00:27:00,880 --> 00:27:05,359
Speaker 1: a particle. Do we have any idea of why a

488
00:27:05,640 --> 00:27:08,800
Speaker 1: down cork would become up cork? Yeah, Like you know,

489
00:27:08,920 --> 00:27:11,040
Speaker 1: why does it down cork decide it wants to be

490
00:27:11,040 --> 00:27:13,159
Speaker 1: an upcork one day? You know, like why isn't it

491
00:27:13,280 --> 00:27:16,800
Speaker 1: just happy being an upcork. It's a great question, and

492
00:27:16,840 --> 00:27:18,920
Speaker 1: it's a really deep question. It's like why does any

493
00:27:19,000 --> 00:27:22,160
Speaker 1: particle decay? You know, why do muance just hang out

494
00:27:22,200 --> 00:27:24,760
Speaker 1: and be muance? Why do they decay to electrons and

495
00:27:24,840 --> 00:27:27,960
Speaker 1: a couple of neutrinos? Why does anything decay? And the

496
00:27:28,080 --> 00:27:31,200
Speaker 1: reason is that the universe is constantly getting colder and

497
00:27:31,400 --> 00:27:35,159
Speaker 1: spreading out. Entropy and statistical mechanics tells us that the

498
00:27:35,280 --> 00:27:38,520
Speaker 1: universe doesn't like to have energy localized in a little spot.

499
00:27:38,800 --> 00:27:41,400
Speaker 1: It likes for it to spread out. Sort of fascinating

500
00:27:41,520 --> 00:27:45,639
Speaker 1: quantum mechanical, the universe likes to occupy multiple quantum states

501
00:27:45,640 --> 00:27:48,160
Speaker 1: instead of like being focused on a single quantum state.

502
00:27:48,280 --> 00:27:51,639
Speaker 1: What that means essentially is that any particle will always

503
00:27:51,720 --> 00:27:56,000
Speaker 1: decay into a lower mass particle. If it's possible for

504
00:27:56,160 --> 00:27:58,560
Speaker 1: you to take a step down the mass ladder to

505
00:27:58,600 --> 00:28:01,359
Speaker 1: break up into smaller particle with less mass than you,

506
00:28:01,520 --> 00:28:04,480
Speaker 1: always will the universe is its constant pressure. It's the

507
00:28:04,480 --> 00:28:07,000
Speaker 1: same as if you have like a hot object sitting

508
00:28:07,040 --> 00:28:09,400
Speaker 1: on a surface, it's going to spread its energy out

509
00:28:09,640 --> 00:28:11,760
Speaker 1: to the neighboring stuff. The same way you have a

510
00:28:11,880 --> 00:28:14,880
Speaker 1: very high mass particle. It wants to break up into

511
00:28:14,960 --> 00:28:17,840
Speaker 1: lower mass particles. And it turns out that the neutron

512
00:28:18,160 --> 00:28:21,560
Speaker 1: is heavier than the proton just by a little bit,

513
00:28:22,160 --> 00:28:24,280
Speaker 1: and so the neutron can do this. It can take

514
00:28:24,280 --> 00:28:27,200
Speaker 1: a step down into a lower energy configuration. So the

515
00:28:27,280 --> 00:28:29,639
Speaker 1: neutron is a higher energy state, which means it has

516
00:28:29,640 --> 00:28:32,199
Speaker 1: a little bit more mass. And decays down into a proton.

517
00:28:32,320 --> 00:28:35,320
Speaker 1: It does this by flipping one of the down corks

518
00:28:35,400 --> 00:28:38,640
Speaker 1: into an upcorp. So it's my freshly biked neutron. It's

519
00:28:38,720 --> 00:28:40,920
Speaker 1: kind of like a hot soup flay. And then if

520
00:28:40,960 --> 00:28:43,320
Speaker 1: I leave that out, it's going to cool down and

521
00:28:43,360 --> 00:28:47,680
Speaker 1: then collapse into a proton. I got it. Oh, speaking

522
00:28:47,720 --> 00:28:49,959
Speaker 1: of su fla, I did leave one out, so we're

523
00:28:50,000 --> 00:28:52,560
Speaker 1: gonna need to take a quick break while I go

524
00:28:52,800 --> 00:28:55,000
Speaker 1: check on that. I'm sure it's fine, uh, And then

525
00:28:55,560 --> 00:28:58,520
Speaker 1: we hopefully will come back and I'll still have my

526
00:28:58,840 --> 00:29:01,520
Speaker 1: neutron soup fla attack and we'll continue talking about how

527
00:29:01,600 --> 00:29:04,560
Speaker 1: long do these neutrons live? How do I resuscitate my

528
00:29:04,680 --> 00:29:20,440
Speaker 1: neutron souflay? So we'll be right back. Okay, So bad

529
00:29:20,560 --> 00:29:23,960
Speaker 1: news is that my soup fla did collapse. The good

530
00:29:24,080 --> 00:29:26,720
Speaker 1: news is I guess it's now our proton, so all

531
00:29:26,840 --> 00:29:31,240
Speaker 1: isn't lost. That's always the backup plan for your neutron souflay.

532
00:29:31,600 --> 00:29:34,360
Speaker 1: Turns out, charge it up to a proton south lag.

533
00:29:35,360 --> 00:29:38,040
Speaker 1: Like you know, a sou flay that collapses is still

534
00:29:38,080 --> 00:29:41,480
Speaker 1: gonna taste pretty good. So a neutron that decays into

535
00:29:41,520 --> 00:29:45,440
Speaker 1: a proton is still a particle. It'll still build things

536
00:29:45,680 --> 00:29:50,080
Speaker 1: like delicious soufleas exactly. And so we were talking about

537
00:29:50,280 --> 00:29:53,840
Speaker 1: how neutrons decay and how they turn into protons, and

538
00:29:54,280 --> 00:29:56,960
Speaker 1: people might be wondering, like what's going on with the

539
00:29:57,040 --> 00:30:00,760
Speaker 1: electric charges? Like can you just turn a down cork

540
00:30:00,920 --> 00:30:04,360
Speaker 1: which is charged minus a third into an upcork, which

541
00:30:04,480 --> 00:30:07,320
Speaker 1: is charged plus two thirds? Like charge doesn't just come

542
00:30:07,360 --> 00:30:09,760
Speaker 1: for fruit. You can't just like create charge. How do

543
00:30:09,880 --> 00:30:13,600
Speaker 1: you just convert a neutron into a plus one charged proton? Right?

544
00:30:13,760 --> 00:30:16,320
Speaker 1: The answer is that the universe does do the accounting

545
00:30:16,440 --> 00:30:19,640
Speaker 1: quite carefully. And when a downcourt converts into an upcork,

546
00:30:19,760 --> 00:30:23,440
Speaker 1: it also emits a W particle. Okay, now you're just

547
00:30:23,600 --> 00:30:27,480
Speaker 1: making up particles. What's the W particle? So a W

548
00:30:27,720 --> 00:30:32,120
Speaker 1: particle is the force particle for the weak nuclear force. Right,

549
00:30:32,120 --> 00:30:35,160
Speaker 1: we got all these different forces. We have electromagnetism, we

550
00:30:35,240 --> 00:30:37,840
Speaker 1: have a strong force, we have the weak force. Each

551
00:30:37,960 --> 00:30:40,680
Speaker 1: one we think of as carried by a particle. So

552
00:30:40,800 --> 00:30:45,280
Speaker 1: photons carry the electromagnetic force, gluons carry these strong force.

553
00:30:45,760 --> 00:30:49,000
Speaker 1: W particles carry the weak nuclear force. The weak nuclear

554
00:30:49,080 --> 00:30:52,960
Speaker 1: force is like the weirdest, strangest, most amazing sporce there is.

555
00:30:53,320 --> 00:30:55,560
Speaker 1: It's not very powerful, but it can do all sorts

556
00:30:55,600 --> 00:30:57,640
Speaker 1: of really strange stuff. And we have a couple of

557
00:30:57,720 --> 00:31:00,920
Speaker 1: podcast episodes dedicated just to under standing the weak force

558
00:31:01,000 --> 00:31:03,760
Speaker 1: and parity violation and all that crazy stuff. But in

559
00:31:03,840 --> 00:31:06,600
Speaker 1: this case, the weak force is here to help balance

560
00:31:06,640 --> 00:31:09,320
Speaker 1: the books. When a down cork becomes an upcork, that

561
00:31:09,400 --> 00:31:12,600
Speaker 1: sort of costs one electric charge. You've gone from a

562
00:31:12,680 --> 00:31:15,040
Speaker 1: neutron to a proton. So to balance the books, you

563
00:31:15,120 --> 00:31:18,240
Speaker 1: also need to create something with negative charge. The amazing

564
00:31:18,280 --> 00:31:21,560
Speaker 1: thing about these W particles is that they do have charge,

565
00:31:21,720 --> 00:31:24,800
Speaker 1: so the W can have a positive or a negative charge.

566
00:31:24,840 --> 00:31:29,040
Speaker 1: In this case, you emit a W minus which balances

567
00:31:29,080 --> 00:31:31,320
Speaker 1: the charges. So have you've gone from a neutron to

568
00:31:31,440 --> 00:31:34,520
Speaker 1: a proton and a W minus. So the proton is

569
00:31:34,520 --> 00:31:36,960
Speaker 1: plus one, the W minus is minus one. That all

570
00:31:37,000 --> 00:31:40,120
Speaker 1: adds up to zero. The W minus itself doesn't live

571
00:31:40,200 --> 00:31:42,720
Speaker 1: for very long and it turns into an electron and

572
00:31:42,800 --> 00:31:46,280
Speaker 1: an anti neutrino. Okay, so an electron does have a

573
00:31:46,360 --> 00:31:49,400
Speaker 1: negative charge, so it still retains that negative charge. What

574
00:31:49,600 --> 00:31:52,400
Speaker 1: is an anti neutrino? Yeah, and anti neutrino is one

575
00:31:52,440 --> 00:31:54,880
Speaker 1: of these little ghostly particles. So you and I are

576
00:31:54,960 --> 00:31:57,680
Speaker 1: made of protons and neutrons and electrons, which are made

577
00:31:57,680 --> 00:32:00,479
Speaker 1: of upcorks and down corks. But there's this other particle,

578
00:32:00,560 --> 00:32:04,520
Speaker 1: this neutrino, which exists in the universe and can be made,

579
00:32:04,760 --> 00:32:07,760
Speaker 1: and the Sun is pumping out like jillions of them

580
00:32:07,880 --> 00:32:10,720
Speaker 1: every second. But they're very strange little particles because they

581
00:32:10,760 --> 00:32:14,160
Speaker 1: don't appear normally inside matter, Like I am not made

582
00:32:14,160 --> 00:32:16,440
Speaker 1: out of neutrinos, and you're not made out of neutrinos

583
00:32:16,440 --> 00:32:19,520
Speaker 1: in any way. But it's something that the universe can exist.

584
00:32:19,600 --> 00:32:22,720
Speaker 1: It's like a Lego building block that's never used in

585
00:32:22,960 --> 00:32:25,520
Speaker 1: making anything bigger or larger. It's just sort of like

586
00:32:25,640 --> 00:32:29,360
Speaker 1: floating around in the universe. Yeah, I remember those Lego blocks.

587
00:32:29,400 --> 00:32:33,600
Speaker 1: They're usually like these like weirdly shaped, clear little ones,

588
00:32:33,720 --> 00:32:36,600
Speaker 1: and they would just kind of not be used in anything,

589
00:32:36,640 --> 00:32:40,480
Speaker 1: get quickly lost or eaten exactly. And neutrinos are strange

590
00:32:40,520 --> 00:32:43,440
Speaker 1: because they're very very low mass, they're almost massless but

591
00:32:43,600 --> 00:32:46,440
Speaker 1: not entirely, and they also hardly interact. They don't have

592
00:32:46,480 --> 00:32:49,480
Speaker 1: any electric charge, they don't have the strong force, so

593
00:32:49,560 --> 00:32:52,640
Speaker 1: they basically just fly through everything. So neutrino when it's produced,

594
00:32:52,720 --> 00:32:55,520
Speaker 1: can fly through like a star without blinking an eye

595
00:32:55,600 --> 00:32:59,320
Speaker 1: into a neutrino. The whole universe is transparent, and so

596
00:32:59,480 --> 00:33:01,920
Speaker 1: that just sort of flies out. And so to summarize them,

597
00:33:01,960 --> 00:33:05,600
Speaker 1: when a neutron decays, it turns into a proton, an electron,

598
00:33:05,840 --> 00:33:08,800
Speaker 1: and then an anti neutrino, and so that's what happens

599
00:33:08,800 --> 00:33:12,000
Speaker 1: when a neutron decase. That's spooky. So neutron does kind

600
00:33:12,000 --> 00:33:18,680
Speaker 1: of create a ghost when it decays scientifically speaking exactly.

601
00:33:18,760 --> 00:33:20,520
Speaker 1: And we should also be clear about what we mean

602
00:33:20,640 --> 00:33:23,680
Speaker 1: about neutron decay because people might be wondering, like, does

603
00:33:23,720 --> 00:33:26,080
Speaker 1: that mean that the neutrons that are in my body

604
00:33:26,320 --> 00:33:28,800
Speaker 1: right now are going to like break up, like they

605
00:33:28,800 --> 00:33:31,080
Speaker 1: don't last for long? Like, am I dying because my

606
00:33:31,160 --> 00:33:33,680
Speaker 1: neutrons are decaying? Yeah, I want to know if I

607
00:33:33,760 --> 00:33:37,240
Speaker 1: will spontaneously turn into a pile of protons, electrons and

608
00:33:37,320 --> 00:33:42,000
Speaker 1: ghost particles in my best interest to know. And that's

609
00:33:42,040 --> 00:33:45,280
Speaker 1: one of the really fascinating mysteries about neutron decay is

610
00:33:45,320 --> 00:33:48,080
Speaker 1: that neutrons do decay, but only sort of like when

611
00:33:48,160 --> 00:33:51,760
Speaker 1: they're on their own, floating out in the universe. When

612
00:33:51,800 --> 00:33:54,719
Speaker 1: a neutron is inside a nucleus when it's hanging out

613
00:33:54,800 --> 00:33:57,440
Speaker 1: with other protons. When it and it's proton brethren have

614
00:33:57,560 --> 00:34:00,240
Speaker 1: built something larger, then he can last forever. You know,

615
00:34:00,360 --> 00:34:03,760
Speaker 1: you have a stable nucleus like iron, right, iron can

616
00:34:03,880 --> 00:34:06,200
Speaker 1: live forever. We think if you have an iron atom

617
00:34:06,480 --> 00:34:09,480
Speaker 1: sitting alone in the universe, it's made of protons and

618
00:34:09,560 --> 00:34:12,360
Speaker 1: neutrons and electrons, it can sit there, we think forever.

619
00:34:12,520 --> 00:34:14,799
Speaker 1: We think it's stable. If it's not perturbed, it will

620
00:34:14,880 --> 00:34:18,200
Speaker 1: just hang out until the end of time. That includes

621
00:34:18,400 --> 00:34:22,400
Speaker 1: the neutrons inside the iron right there there. They're neutrons.

622
00:34:22,600 --> 00:34:25,440
Speaker 1: They will hang out forever. Their down corks are not

623
00:34:25,520 --> 00:34:28,320
Speaker 1: going to flip into up corks, turning them into protons.

624
00:34:28,680 --> 00:34:33,200
Speaker 1: This is like the ultimate ziplock bag techniques. So keeping

625
00:34:33,440 --> 00:34:37,680
Speaker 1: neutrons fresh forever. I love that technology for my strawberries.

626
00:34:38,040 --> 00:34:41,480
Speaker 1: They're so good, but they go bad so fast. Exactly so,

627
00:34:41,560 --> 00:34:44,279
Speaker 1: the neutrons in your body are in atoms, and so

628
00:34:44,400 --> 00:34:47,200
Speaker 1: they are likely to last as long as those atoms last.

629
00:34:47,280 --> 00:34:49,200
Speaker 1: But if you take a neutron out of the atom

630
00:34:49,239 --> 00:34:52,040
Speaker 1: and you have it by itself hanging out in free space,

631
00:34:52,280 --> 00:34:54,760
Speaker 1: now we can talk about the lifetime of that neutron.

632
00:34:54,880 --> 00:34:57,040
Speaker 1: What does it do when it's left alone? Well, the

633
00:34:57,080 --> 00:35:00,360
Speaker 1: neutrons sitting there in empty space last till end of

634
00:35:00,480 --> 00:35:02,840
Speaker 1: time or will it decay? So if you put like

635
00:35:02,880 --> 00:35:05,640
Speaker 1: a proton and then a neutron and electron, you have

636
00:35:05,760 --> 00:35:07,759
Speaker 1: them just hanging out in free space and you just wait.

637
00:35:07,920 --> 00:35:10,680
Speaker 1: The proton will last forever, we think, the electron will

638
00:35:10,760 --> 00:35:13,920
Speaker 1: last forever, we think, but the neutron will not. The

639
00:35:14,000 --> 00:35:17,479
Speaker 1: neutron by itself will decay. One of those down corks

640
00:35:17,560 --> 00:35:20,440
Speaker 1: will flip. That's the actual sound it makes, and it

641
00:35:20,440 --> 00:35:24,000
Speaker 1: will turn into a proton electron and an anti neutrino.

642
00:35:24,160 --> 00:35:25,839
Speaker 1: So when we talked about the neutron last time, we're

643
00:35:25,840 --> 00:35:29,239
Speaker 1: talking about the isolated neutron, not a neutron that's inside

644
00:35:29,320 --> 00:35:32,560
Speaker 1: the nucleus. So, when it's inside the nucleus, what is

645
00:35:32,640 --> 00:35:35,600
Speaker 1: that zip block effect that is keeping it from decaying. Yeah,

646
00:35:35,640 --> 00:35:37,720
Speaker 1: it's a great question, and there's a lot of mysteries

647
00:35:37,800 --> 00:35:41,040
Speaker 1: there because we don't really understand very well how the

648
00:35:41,160 --> 00:35:44,120
Speaker 1: strong force works. We talked about it briefly a little earlier,

649
00:35:44,239 --> 00:35:47,760
Speaker 1: but when protons and neutrons are locked together inside a nucleus,

650
00:35:47,960 --> 00:35:50,520
Speaker 1: it's not like you just have these particles and they're

651
00:35:50,560 --> 00:35:53,400
Speaker 1: stuck together like legos. They're also talking to each other

652
00:35:53,600 --> 00:35:56,320
Speaker 1: because remember a proton and a neutron, they're not just

653
00:35:56,560 --> 00:36:00,440
Speaker 1: linked together quarks, they're little bags of gluons. When you

654
00:36:00,480 --> 00:36:03,520
Speaker 1: get a proton and neutron close enough together, then their

655
00:36:03,560 --> 00:36:06,880
Speaker 1: gluons talk to each other. Those bags leak a little bit.

656
00:36:07,080 --> 00:36:09,600
Speaker 1: They're not totally separate from each other, and really they

657
00:36:09,640 --> 00:36:12,759
Speaker 1: sort of like weave themselves into a larger mosaic. You

658
00:36:12,880 --> 00:36:16,800
Speaker 1: might wonder inside a heavy hydrogen atom, where you have

659
00:36:16,960 --> 00:36:19,000
Speaker 1: not just a proton, but a proton or a neutron,

660
00:36:19,440 --> 00:36:22,520
Speaker 1: what's making the proton and neutron stick to each other? Right,

661
00:36:22,800 --> 00:36:25,960
Speaker 1: the proton is positively charged, the neutron is negatively charged.

662
00:36:26,200 --> 00:36:27,960
Speaker 1: Why did they stick together at all? Why don't they

663
00:36:28,000 --> 00:36:31,440
Speaker 1: just float apart? The answer is their gluons. When you

664
00:36:31,480 --> 00:36:34,239
Speaker 1: get them that close together, then the gluons inside each

665
00:36:34,280 --> 00:36:37,080
Speaker 1: other's bags talk to each other, and they click together

666
00:36:37,120 --> 00:36:39,960
Speaker 1: into sort of a larger object which is not really

667
00:36:40,040 --> 00:36:44,160
Speaker 1: anymore just and isolated proton, not really any more isolated neutron,

668
00:36:44,320 --> 00:36:47,719
Speaker 1: but this combined object that has these linkages together. So

669
00:36:47,880 --> 00:36:51,160
Speaker 1: is that why when you keep adding neutrons to an

670
00:36:51,280 --> 00:36:54,759
Speaker 1: atom that it becomes maybe less stable because you start

671
00:36:54,920 --> 00:36:57,840
Speaker 1: to weaken those gluon forces. Yeah, you can make it

672
00:36:57,960 --> 00:37:00,960
Speaker 1: less stable or more stable. Right, The way that you

673
00:37:01,120 --> 00:37:04,360
Speaker 1: organize the protons and the neutrons inside the nucleus totally

674
00:37:04,480 --> 00:37:07,200
Speaker 1: determined whether something is stable or not. We have a

675
00:37:07,239 --> 00:37:10,200
Speaker 1: fun podcast episode about the islands of stability and how

676
00:37:10,320 --> 00:37:13,239
Speaker 1: heavy you can make something and keep it stable. We

677
00:37:13,280 --> 00:37:15,839
Speaker 1: don't know the answer to that because the strong force

678
00:37:16,000 --> 00:37:18,919
Speaker 1: is very difficult to do calculations with, Like we can't

679
00:37:18,920 --> 00:37:21,600
Speaker 1: sit down with pencil and paper and solve the quantum

680
00:37:21,640 --> 00:37:24,360
Speaker 1: mechanics of the nucleus the way we can with the

681
00:37:24,440 --> 00:37:27,400
Speaker 1: hydrogen atom. Folks who have done physics in college have

682
00:37:27,480 --> 00:37:29,880
Speaker 1: done like the shortening your equation for the hydrogen atom.

683
00:37:29,920 --> 00:37:32,560
Speaker 1: When we know those equations, we can solve them, we

684
00:37:32,640 --> 00:37:35,040
Speaker 1: can find the states of the electron. We don't know

685
00:37:35,160 --> 00:37:37,439
Speaker 1: how to do those calculations for the strong force because

686
00:37:37,480 --> 00:37:41,400
Speaker 1: it's much more powerful and much more sensitive to tiny details,

687
00:37:41,840 --> 00:37:44,040
Speaker 1: So we don't actually know like the answer to those

688
00:37:44,080 --> 00:37:45,640
Speaker 1: We can't do it with pencil and paper. We have

689
00:37:45,760 --> 00:37:49,320
Speaker 1: massive computers trying to do those calculations, but it's really challenging,

690
00:37:49,719 --> 00:37:52,680
Speaker 1: So mostly it's experimental. We try to like build heavier

691
00:37:52,719 --> 00:37:55,120
Speaker 1: stuff and see if we can keep it together. People

692
00:37:55,200 --> 00:37:57,520
Speaker 1: shoot like neutrons at atoms and see like, oh, can

693
00:37:57,560 --> 00:37:59,680
Speaker 1: I get one to stick in there and make something

694
00:37:59,760 --> 00:38:02,640
Speaker 1: which lasts longer. So it's a whole area of research.

695
00:38:02,880 --> 00:38:06,600
Speaker 1: How do weave protons and neutrons together into stable objects?

696
00:38:06,960 --> 00:38:09,760
Speaker 1: We think that they organize themselves in terms of these shells.

697
00:38:09,920 --> 00:38:12,880
Speaker 1: Is this nuclear shell model that tells you how to

698
00:38:12,960 --> 00:38:16,560
Speaker 1: build protons and neutrons together into a stable nucleus sort

699
00:38:16,600 --> 00:38:20,080
Speaker 1: of analogous to the way electrons organize themselves in shells

700
00:38:20,120 --> 00:38:22,880
Speaker 1: on the outside of the atom. It's really fascinating. So

701
00:38:23,200 --> 00:38:25,439
Speaker 1: I am feeling more and more like a physicist based

702
00:38:25,520 --> 00:38:28,000
Speaker 1: on my childhood because I would try to just build

703
00:38:28,040 --> 00:38:29,840
Speaker 1: the biggest thing out of legos and then kind of

704
00:38:29,920 --> 00:38:32,120
Speaker 1: hold it up and see if it could sustain and

705
00:38:32,200 --> 00:38:34,280
Speaker 1: self for if it would fall apart. And it sounds

706
00:38:34,360 --> 00:38:36,839
Speaker 1: like that's what you guys are doing, just with more

707
00:38:36,920 --> 00:38:40,920
Speaker 1: expensive equipment. But yeah, so that that is interesting is

708
00:38:41,440 --> 00:38:45,520
Speaker 1: you're saying that, like maybe they arrange themselves into shells.

709
00:38:45,600 --> 00:38:48,080
Speaker 1: When you're talking about shells, I'm assuming this is not

710
00:38:48,320 --> 00:38:51,759
Speaker 1: like a mollusk shell or something. So what is a

711
00:38:51,880 --> 00:38:54,719
Speaker 1: shell in terms of particle physics. Yes, when we talk

712
00:38:54,760 --> 00:38:57,839
Speaker 1: about shells we think of like spheres and other arrangements.

713
00:38:58,360 --> 00:39:00,840
Speaker 1: We think of The protons and neutrons inside the nucleus

714
00:39:00,960 --> 00:39:04,560
Speaker 1: have somehow found stable ways to organize themselves into these

715
00:39:04,640 --> 00:39:07,520
Speaker 1: like little mosaics. Instead of thinking about them really as

716
00:39:07,640 --> 00:39:10,400
Speaker 1: protons and neutrons anymore, you really should think about them

717
00:39:10,440 --> 00:39:14,279
Speaker 1: as components of this fabric, this nuclear fabric, which likes

718
00:39:14,320 --> 00:39:16,800
Speaker 1: to weave itself together. And the incredible thing is that

719
00:39:16,920 --> 00:39:20,359
Speaker 1: it's stable, like in many configurations, even for very very

720
00:39:20,400 --> 00:39:23,799
Speaker 1: heavy elements, these things are quite stable. Again, we don't

721
00:39:23,840 --> 00:39:26,680
Speaker 1: really understand it. And so there's two different communities of

722
00:39:26,719 --> 00:39:29,279
Speaker 1: physicists here, the ones that like to make really big

723
00:39:29,400 --> 00:39:32,200
Speaker 1: blobs of protons and neutrons and understand like how are

724
00:39:32,239 --> 00:39:34,200
Speaker 1: they working together? And then there's the folks who just

725
00:39:34,320 --> 00:39:36,480
Speaker 1: want to like dig inside one neutron and say, well,

726
00:39:36,520 --> 00:39:39,720
Speaker 1: let's just study the neutron by itself. Let's zoom inside

727
00:39:39,760 --> 00:39:42,480
Speaker 1: the neutron and see if we can understand what makes

728
00:39:42,600 --> 00:39:45,560
Speaker 1: that cork flip from one to the other. How often

729
00:39:45,600 --> 00:39:47,840
Speaker 1: does that happen? How long does it take? And what

730
00:39:48,000 --> 00:39:50,120
Speaker 1: does that mean about the neutron. So you've got like

731
00:39:50,160 --> 00:39:53,800
Speaker 1: the nuclear physicists studying like huge blobs of neutrons and

732
00:39:54,120 --> 00:39:57,160
Speaker 1: protons inside the nucleus, and they have us particle physicists

733
00:39:57,200 --> 00:39:59,759
Speaker 1: looking to break it apart and see what's inside. That's

734
00:40:00,000 --> 00:40:04,440
Speaker 1: really interesting. So now that we have isolated the neutron,

735
00:40:04,520 --> 00:40:08,560
Speaker 1: it's we've broken apart that atom. It's outside, it's vulnerable.

736
00:40:08,920 --> 00:40:11,600
Speaker 1: Now what happens? So now we can see how long

737
00:40:11,680 --> 00:40:15,200
Speaker 1: it takes to pop into a proton and electron and

738
00:40:15,280 --> 00:40:17,840
Speaker 1: a neutrino. And so this is a really interesting question,

739
00:40:17,920 --> 00:40:20,279
Speaker 1: just like how long does it take? Remember, protons will

740
00:40:20,320 --> 00:40:23,560
Speaker 1: live for trillions of years. There's two amazing things about

741
00:40:23,600 --> 00:40:26,520
Speaker 1: the neutron lifetime how long a neutron will survive on

742
00:40:26,600 --> 00:40:29,279
Speaker 1: its own. First is that it's very short. It's like

743
00:40:29,600 --> 00:40:33,440
Speaker 1: fifteen minutes. The neutron does not last very long. The

744
00:40:33,520 --> 00:40:36,800
Speaker 1: person is that it's basically instantaneous on a cosmic timescale.

745
00:40:36,920 --> 00:40:40,120
Speaker 1: That's right, you know, neutron's last for like fifteen minutes.

746
00:40:40,160 --> 00:40:43,320
Speaker 1: It's it's nothing. You know, cosmically, do you make a neutron?

747
00:40:43,520 --> 00:40:45,480
Speaker 1: You leave it there, you go to get a coffee

748
00:40:45,719 --> 00:40:48,680
Speaker 1: and you come back it's gone. You know, that's kind

749
00:40:48,719 --> 00:40:51,520
Speaker 1: of sad to me. I don't know why. Again, I'm

750
00:40:51,560 --> 00:40:55,320
Speaker 1: like attributing emotions to these things in the universe that,

751
00:40:55,760 --> 00:40:58,160
Speaker 1: as far as I know, don't feel emotions, but it does.

752
00:40:58,280 --> 00:41:03,600
Speaker 1: It seems very um disconcerting. That's something as fundamental as

753
00:41:03,640 --> 00:41:06,560
Speaker 1: a neutron, less about as long as it takes for

754
00:41:07,200 --> 00:41:09,600
Speaker 1: my soup to cool down. Yeah, So if you want

755
00:41:09,640 --> 00:41:11,479
Speaker 1: to build something out of neutrons, and you make yourself

756
00:41:11,480 --> 00:41:13,319
Speaker 1: a big pile of neutrons, you better get to work.

757
00:41:13,400 --> 00:41:15,520
Speaker 1: No time for a coffee break, you know, before you

758
00:41:15,560 --> 00:41:17,799
Speaker 1: get started. Like you got to use them or lose them.

759
00:41:18,000 --> 00:41:20,840
Speaker 1: The other fascinating thing about the neutron lifetime is we

760
00:41:20,920 --> 00:41:24,279
Speaker 1: don't actually know what it is. We've tried to measure it,

761
00:41:24,520 --> 00:41:27,000
Speaker 1: and we have two very different ways of measuring the

762
00:41:27,080 --> 00:41:30,560
Speaker 1: neutron lifetime, like two very different experimental setups, and they

763
00:41:30,600 --> 00:41:34,279
Speaker 1: get different results. Like one group put a bunch of

764
00:41:34,320 --> 00:41:36,680
Speaker 1: them in a bottle and wait to see how many

765
00:41:36,760 --> 00:41:39,040
Speaker 1: they have like ten minutes later, and they get an

766
00:41:39,040 --> 00:41:42,719
Speaker 1: answer of like fourteen minutes and thirty nine seconds. And

767
00:41:42,880 --> 00:41:45,520
Speaker 1: other folks use a beam of neutrons and count how

768
00:41:45,640 --> 00:41:48,720
Speaker 1: many protons come out, and they get a different answer.

769
00:41:49,160 --> 00:41:52,440
Speaker 1: They get fourteen minutes and forty eight seconds, So there's

770
00:41:52,480 --> 00:41:56,520
Speaker 1: like a nine second difference, so we don't even actually know. Well,

771
00:41:56,600 --> 00:41:59,200
Speaker 1: I see what the problem is. Probably one group is

772
00:41:59,400 --> 00:42:02,319
Speaker 1: using one Mississippis and the other group is using one

773
00:42:02,400 --> 00:42:05,920
Speaker 1: potato to potato. You have solved this mystery. It is

774
00:42:06,120 --> 00:42:09,920
Speaker 1: funded physicists for decades and today you have figured it out. Katie. Wow,

775
00:42:10,000 --> 00:42:13,400
Speaker 1: thank you so much your contributions to particle physics. So

776
00:42:13,800 --> 00:42:18,080
Speaker 1: you're welcome everyone for me solving this physics problem. And

777
00:42:18,320 --> 00:42:21,680
Speaker 1: when we get back, um, I'm sure Daniel will make

778
00:42:21,760 --> 00:42:24,240
Speaker 1: some kind of argument that no, it's not as simple

779
00:42:24,400 --> 00:42:28,520
Speaker 1: as one Mississippi or one potato, but you know all

780
00:42:28,560 --> 00:42:30,480
Speaker 1: of them have a short break to work that one out,

781
00:42:30,520 --> 00:42:46,480
Speaker 1: because I think my argument is prettier tight. Okay, And

782
00:42:46,680 --> 00:42:49,960
Speaker 1: so we're back and we've got this. Two teams of

783
00:42:50,440 --> 00:42:54,080
Speaker 1: I would assume, very smart, very professional scientists, but they're

784
00:42:54,120 --> 00:42:57,959
Speaker 1: coming to slightly different answers on how long it takes

785
00:42:58,080 --> 00:43:02,240
Speaker 1: for a neutron on to decay. One group fourteen minutes

786
00:43:02,280 --> 00:43:05,680
Speaker 1: thirty nine seconds, the other group fourteen minutes and forty

787
00:43:05,719 --> 00:43:08,520
Speaker 1: eight seconds. So what the heck is going wrong? Is

788
00:43:08,600 --> 00:43:12,560
Speaker 1: one group just wrong? We don't know. It's really fascinating

789
00:43:12,640 --> 00:43:15,279
Speaker 1: to have watched this series of experiments over a couple

790
00:43:15,360 --> 00:43:17,680
Speaker 1: of decades. You know, whenever you do something in physics,

791
00:43:17,760 --> 00:43:20,040
Speaker 1: you try to do it a couple of ways because

792
00:43:20,160 --> 00:43:22,799
Speaker 1: it's easy to make mistakes. You're doing something hard, you're

793
00:43:22,800 --> 00:43:25,560
Speaker 1: making assumptions, you're doing the best you can, but it's

794
00:43:25,640 --> 00:43:27,640
Speaker 1: very easy for mistakes to creep in, and so it's

795
00:43:27,680 --> 00:43:30,279
Speaker 1: great practice to have two different groups of people doing

796
00:43:30,320 --> 00:43:33,360
Speaker 1: it two different ways, making different mistakes. In the end,

797
00:43:33,400 --> 00:43:36,040
Speaker 1: we're supposed to be measuring the same thing about the universe.

798
00:43:36,120 --> 00:43:38,480
Speaker 1: The neutron should just have a certain lifetime and we

799
00:43:38,480 --> 00:43:40,320
Speaker 1: should be able to measure it and get the same answer.

800
00:43:40,480 --> 00:43:42,680
Speaker 1: And if we don't, that means that one of our

801
00:43:42,719 --> 00:43:45,520
Speaker 1: assumptions is wrong, where somebody is making a mistake, or

802
00:43:45,760 --> 00:43:48,840
Speaker 1: there's something deeper going on. Right, something is happening in

803
00:43:48,920 --> 00:43:51,160
Speaker 1: one of these experiments that we don't understand, which could

804
00:43:51,160 --> 00:43:54,240
Speaker 1: be like a clue as to how the universe works.

805
00:43:54,360 --> 00:43:56,960
Speaker 1: So originally these two groups made these measurements and they

806
00:43:56,960 --> 00:43:59,200
Speaker 1: didn't get the same answer, But nobody was worried because

807
00:43:59,239 --> 00:44:02,000
Speaker 1: their airbor were pretty large. You know, the difference was

808
00:44:02,080 --> 00:44:04,120
Speaker 1: like eight or nine seconds, but the uncertainty was like

809
00:44:04,239 --> 00:44:06,960
Speaker 1: thirty seconds. So people have thought, we'll just keep working

810
00:44:07,239 --> 00:44:09,440
Speaker 1: and maybe the numbers will creep together as they get

811
00:44:09,520 --> 00:44:13,080
Speaker 1: more precise. The opposite has happened. Both groups have been

812
00:44:13,120 --> 00:44:16,560
Speaker 1: working hard to reduce those uncertainties, you know, figure out

813
00:44:16,600 --> 00:44:19,480
Speaker 1: the sources of error and potential bias in their experiments,

814
00:44:19,680 --> 00:44:22,319
Speaker 1: shaving them off, calibrating them, cross checking them. And as

815
00:44:22,360 --> 00:44:24,719
Speaker 1: the uncertainties have decreased, and now those uncertainties are like

816
00:44:24,920 --> 00:44:27,560
Speaker 1: less than a second or two, the size of the

817
00:44:27,680 --> 00:44:30,520
Speaker 1: difference between the two experiments has stayed the same. In fact,

818
00:44:30,600 --> 00:44:32,799
Speaker 1: it's even crept up a little bit, from like eight

819
00:44:32,880 --> 00:44:37,920
Speaker 1: to almost ten seconds. Okay, so we have Team Bottle,

820
00:44:38,000 --> 00:44:41,239
Speaker 1: I'm going to say, and then Team Beam. So what

821
00:44:41,440 --> 00:44:44,880
Speaker 1: are these teams doing? Because they have very different methods

822
00:44:44,960 --> 00:44:48,759
Speaker 1: going on here, which that may somewhat explain why they're

823
00:44:48,800 --> 00:44:52,040
Speaker 1: getting different results. So first let's go over like Team Bottle.

824
00:44:52,120 --> 00:44:55,120
Speaker 1: What is Team Bottle doing just you know, shaking up

825
00:44:55,160 --> 00:44:57,640
Speaker 1: some neutrons and a bottle, seeing what happens to them.

826
00:44:57,880 --> 00:45:00,800
Speaker 1: That's basically, yeah, they have a new tron source. This

827
00:45:00,880 --> 00:45:03,319
Speaker 1: is actually at Los Alumos, New Mexico, where I grew up.

828
00:45:03,440 --> 00:45:05,759
Speaker 1: I was wasn't involved in this experiment. It's a huge

829
00:45:05,800 --> 00:45:09,200
Speaker 1: facility there. As far as you know. Anyways, go on,

830
00:45:10,560 --> 00:45:14,080
Speaker 1: I may have been unwittingly roped into this experiment. They

831
00:45:14,160 --> 00:45:16,759
Speaker 1: have a bunch of neutrons there and basically they put

832
00:45:16,840 --> 00:45:18,960
Speaker 1: them in a bottle. They get them ultra cold, so

833
00:45:19,000 --> 00:45:21,040
Speaker 1: they're not moving very fast, and neutrons are a bit

834
00:45:21,120 --> 00:45:23,120
Speaker 1: hard to store because they don't have electric charts, so

835
00:45:23,160 --> 00:45:26,759
Speaker 1: you can't use magnetic fields or electric fields to control them.

836
00:45:26,960 --> 00:45:29,279
Speaker 1: You have to use gravity to get them cold. So

837
00:45:29,360 --> 00:45:31,719
Speaker 1: they slow down and let them just like fall into

838
00:45:31,760 --> 00:45:35,239
Speaker 1: this container. They call it the bathtub, And basically they

839
00:45:35,320 --> 00:45:37,759
Speaker 1: just collect a bunch of neutrons. They very carefully count

840
00:45:37,800 --> 00:45:39,760
Speaker 1: how many introns they start with, and then they measure

841
00:45:39,760 --> 00:45:41,520
Speaker 1: the number of neutrons in their bottle, and then they

842
00:45:41,600 --> 00:45:43,880
Speaker 1: come back ten minutes later, measured again. And they come

843
00:45:43,880 --> 00:45:45,840
Speaker 1: back ten minutes later and they measure it again. And

844
00:45:45,920 --> 00:45:47,960
Speaker 1: that's the essence of the experiment, is like, if you

845
00:45:48,000 --> 00:45:49,960
Speaker 1: think something doesn't last very long, put a bunch of

846
00:45:50,000 --> 00:45:52,200
Speaker 1: them in a bottle. Count how many you have come

847
00:45:52,239 --> 00:45:54,920
Speaker 1: back later and count them again. So it's very simple

848
00:45:55,000 --> 00:45:57,719
Speaker 1: experiment in that way. So you've got this this ice

849
00:45:57,840 --> 00:46:01,840
Speaker 1: cold bottle of delicious new atron's man that makes me thirsty.

850
00:46:02,000 --> 00:46:04,399
Speaker 1: And so they would measure these and they would find

851
00:46:04,520 --> 00:46:07,239
Speaker 1: that they are sort of disappearing at a certain rate,

852
00:46:07,440 --> 00:46:10,279
Speaker 1: and that is how they got at fourteen minutes and

853
00:46:10,320 --> 00:46:13,320
Speaker 1: thirty nine seconds exactly. The important thing to understand is

854
00:46:13,360 --> 00:46:16,560
Speaker 1: that the neutron lifetime doesn't mean that every neutron has

855
00:46:16,600 --> 00:46:19,520
Speaker 1: a clock in it and it expires exactly after fourteen

856
00:46:19,560 --> 00:46:23,000
Speaker 1: minutes and thirty nine seconds. It's an exponential decay. Every

857
00:46:23,080 --> 00:46:26,440
Speaker 1: neutron has a probability to decay in any moment. And

858
00:46:26,640 --> 00:46:29,600
Speaker 1: if some fraction of your neutrons will decay in shorter time,

859
00:46:29,680 --> 00:46:31,840
Speaker 1: and a fraction of the neutrons will last longer, just

860
00:46:31,960 --> 00:46:35,000
Speaker 1: like radioactive decay, it's the same fundamental process. In fact,

861
00:46:35,040 --> 00:46:38,080
Speaker 1: it is that process protons turning into neutrons, which drives

862
00:46:38,120 --> 00:46:41,480
Speaker 1: also radioactive decay. So you don't like watch one neutron,

863
00:46:41,640 --> 00:46:43,719
Speaker 1: just ask how long did it live. Have a whole

864
00:46:43,760 --> 00:46:46,560
Speaker 1: population of neutrons, and you count how many you have

865
00:46:46,719 --> 00:46:49,160
Speaker 1: over time, and you fit that to a function and

866
00:46:49,239 --> 00:46:51,960
Speaker 1: exponential decay, and you measure sort of the parameter the

867
00:46:52,080 --> 00:46:54,560
Speaker 1: slope of that function. So it's a bit more than

868
00:46:54,640 --> 00:46:56,840
Speaker 1: just watching one neutron decay. That's why you have a

869
00:46:56,880 --> 00:46:59,399
Speaker 1: population of them. So they have these in a little

870
00:46:59,480 --> 00:47:01,359
Speaker 1: bathtub and then every once in a while they're trying

871
00:47:01,360 --> 00:47:03,440
Speaker 1: to count all of them. They pushed them against this

872
00:47:03,560 --> 00:47:06,360
Speaker 1: counter which is covered in boron and zinc, and that

873
00:47:06,560 --> 00:47:08,560
Speaker 1: makes the neutrons give off a little flash of light,

874
00:47:08,600 --> 00:47:10,799
Speaker 1: and they count how many flashes of light they saw,

875
00:47:11,080 --> 00:47:13,399
Speaker 1: and that tells them how many neutrons they have left

876
00:47:13,520 --> 00:47:16,160
Speaker 1: I see. So these two experiments would be like two

877
00:47:16,520 --> 00:47:22,399
Speaker 1: groups of alien scientists measuring the average lifespan of a human. Like, sure,

878
00:47:22,480 --> 00:47:24,680
Speaker 1: our lifespans are going to differ, but they're not going

879
00:47:24,760 --> 00:47:27,680
Speaker 1: to differ by like hundreds of years. They're going to

880
00:47:27,840 --> 00:47:29,960
Speaker 1: differ by a matter of a few years. And so

881
00:47:30,560 --> 00:47:33,920
Speaker 1: you should in theory, even if these two alien scientists

882
00:47:34,000 --> 00:47:37,800
Speaker 1: groups have different methods of measuring our lifespan, they should

883
00:47:37,840 --> 00:47:40,200
Speaker 1: in theory be able to both come up with the

884
00:47:40,400 --> 00:47:43,440
Speaker 1: same average lifespan. But in this case they're not. So

885
00:47:43,560 --> 00:47:46,160
Speaker 1: then what is what is Team Beam doing? The Team

886
00:47:46,200 --> 00:47:48,800
Speaker 1: Beam is taking the opposite approach, where his team Bottle

887
00:47:48,880 --> 00:47:51,600
Speaker 1: is saying, let's count how many neutrons we still have left,

888
00:47:51,680 --> 00:47:54,920
Speaker 1: Team Beam is asking how many neutrons disappear. So they

889
00:47:54,960 --> 00:47:57,600
Speaker 1: have a beam of neutrons that they create, and they

890
00:47:57,680 --> 00:48:01,040
Speaker 1: count how many protons are created within these beams, because

891
00:48:01,080 --> 00:48:04,240
Speaker 1: remember a neutron decays and it decays into a proton,

892
00:48:04,680 --> 00:48:07,839
Speaker 1: So to count how many neutrons have disappeared, they count

893
00:48:07,880 --> 00:48:10,720
Speaker 1: how many protons are created. And so instead of counting

894
00:48:10,719 --> 00:48:13,319
Speaker 1: how many neutrons they still have, like the Bottle guys

895
00:48:13,360 --> 00:48:16,560
Speaker 1: are doing, they're counting how many neutrons have left the room.

896
00:48:16,760 --> 00:48:19,640
Speaker 1: So in the analogy you were talking about with human lifetime,

897
00:48:19,840 --> 00:48:22,359
Speaker 1: instead of counting how many humans do we still have left,

898
00:48:22,480 --> 00:48:26,200
Speaker 1: they're counting graves. I see. I mean it makes me wonder.

899
00:48:26,360 --> 00:48:29,640
Speaker 1: And again this is probably you know, me strolling in

900
00:48:30,000 --> 00:48:34,359
Speaker 1: without having done the rigorous testing that Team Beam has done.

901
00:48:34,400 --> 00:48:38,160
Speaker 1: But like, could there be like some infiltration of protons,

902
00:48:38,239 --> 00:48:41,560
Speaker 1: like protons coming from some other source that is messing

903
00:48:41,640 --> 00:48:44,400
Speaker 1: with their results. Absolutely, that's the kind of thing that

904
00:48:44,480 --> 00:48:46,920
Speaker 1: they've been thinking about for like the last twenty years.

905
00:48:47,040 --> 00:48:49,080
Speaker 1: So you're right, it's something to be worried about, but

906
00:48:49,160 --> 00:48:52,600
Speaker 1: they're very careful. They shield their experiments that magnetic fields

907
00:48:52,640 --> 00:48:55,600
Speaker 1: to prevent anything from creeping in, and they filter these

908
00:48:55,640 --> 00:48:58,879
Speaker 1: protons out using magnetic fields and very careful to only

909
00:48:58,960 --> 00:49:01,920
Speaker 1: count the protons that they think come from their beam.

910
00:49:02,040 --> 00:49:04,600
Speaker 1: So each experiment has like a long list of ways

911
00:49:04,719 --> 00:49:06,879
Speaker 1: that they can get it wrong. And over the last

912
00:49:06,920 --> 00:49:09,560
Speaker 1: ten years they've been like going down that list and thinking,

913
00:49:09,719 --> 00:49:11,880
Speaker 1: how can we check this, How do we really know

914
00:49:12,080 --> 00:49:14,360
Speaker 1: this is true? Can we do this another way just

915
00:49:14,480 --> 00:49:17,080
Speaker 1: to verify, just like as a sanity check, maybe there's

916
00:49:17,120 --> 00:49:19,600
Speaker 1: something going wrong here. And they've gone down that list

917
00:49:19,840 --> 00:49:22,520
Speaker 1: and nobody's found any basic mistakes, and as a result,

918
00:49:22,600 --> 00:49:25,640
Speaker 1: they've been able to shave down their uncertainty because now

919
00:49:25,680 --> 00:49:28,120
Speaker 1: they have like multiple ways of doing every step of

920
00:49:28,200 --> 00:49:31,960
Speaker 1: their experiment to convinced themselves that their number is correct.

921
00:49:32,239 --> 00:49:34,799
Speaker 1: So we still have Team Bottle and Team Beam doing

922
00:49:34,920 --> 00:49:37,520
Speaker 1: very careful work. Nobody has an idea for what might

923
00:49:37,600 --> 00:49:40,319
Speaker 1: be different where the mistake could be, but they're still

924
00:49:40,440 --> 00:49:43,839
Speaker 1: getting different answers. Also, bringing it back to the aliens

925
00:49:44,280 --> 00:49:47,919
Speaker 1: observing Earth analogy, I mean, I wonder if maybe there

926
00:49:48,000 --> 00:49:51,759
Speaker 1: could like these teams could be doing everything perfectly and

927
00:49:52,160 --> 00:49:55,880
Speaker 1: executing the experiments perfectly, still getting the different results, but

928
00:49:56,000 --> 00:49:59,080
Speaker 1: not because they made an error, but because there's something

929
00:49:59,120 --> 00:50:02,680
Speaker 1: else going on. So, for instance, maybe if the Team

930
00:50:02,800 --> 00:50:06,479
Speaker 1: Alien one is just counting the number of humans left

931
00:50:06,520 --> 00:50:08,759
Speaker 1: after a certain amount of time and average getting the

932
00:50:08,920 --> 00:50:13,359
Speaker 1: lifespan average from that, they may not be taking into

933
00:50:13,400 --> 00:50:16,719
Speaker 1: account like a new births or something. And then for

934
00:50:17,320 --> 00:50:20,560
Speaker 1: Team Alien just measuring the graves. You know, what if

935
00:50:20,600 --> 00:50:22,879
Speaker 1: you have a grave that has like more than one

936
00:50:23,000 --> 00:50:25,719
Speaker 1: person in it, So could there be something going on

937
00:50:26,719 --> 00:50:29,719
Speaker 1: where these these two you know, let's not blame the

938
00:50:29,760 --> 00:50:33,000
Speaker 1: groups of scientists or the intern or the janitor. Nobody's

939
00:50:33,040 --> 00:50:37,080
Speaker 1: doing anything wrong. But they are actually correct. But just

940
00:50:37,400 --> 00:50:40,560
Speaker 1: because their method of measurement is different, there is some

941
00:50:40,960 --> 00:50:45,480
Speaker 1: some mysterious mechanism going on that is creating that difference. Yes, absolutely,

942
00:50:45,600 --> 00:50:47,960
Speaker 1: that is sort of the hope, right. The boring answer

943
00:50:48,160 --> 00:50:50,160
Speaker 1: is like, oh, it turns out the cable wasn't plugged

944
00:50:50,200 --> 00:50:52,760
Speaker 1: in right, or this temperature was set to the wrong number,

945
00:50:52,960 --> 00:50:55,239
Speaker 1: and like you know, from an experimental point of view,

946
00:50:55,239 --> 00:50:57,560
Speaker 1: that would be satisfied to figure it out. More exciting

947
00:50:57,600 --> 00:50:59,279
Speaker 1: would be is if it reveals that one of the

948
00:50:59,360 --> 00:51:02,480
Speaker 1: assumptions that are made that suggests that these two experiments

949
00:51:02,480 --> 00:51:05,520
Speaker 1: should be getting the same answer are fundamentally wrong. So

950
00:51:05,640 --> 00:51:08,120
Speaker 1: people have been very creative about this, and there is

951
00:51:08,280 --> 00:51:11,560
Speaker 1: one cool idea floating out there that maybe when the

952
00:51:11,640 --> 00:51:15,439
Speaker 1: neutron decays, it doesn't always decay into a proton. Maybe

953
00:51:15,640 --> 00:51:19,719
Speaker 1: sometimes it decays into something else like dark matter. Some

954
00:51:19,880 --> 00:51:22,919
Speaker 1: tiny fraction of time, the neutron turns into dark matter,

955
00:51:23,160 --> 00:51:26,120
Speaker 1: and that would explain this difference because remember that the

956
00:51:26,280 --> 00:51:29,240
Speaker 1: beam folks, they won't see it if the neutron decays

957
00:51:29,280 --> 00:51:32,040
Speaker 1: into something else. They only count the number of times

958
00:51:32,080 --> 00:51:34,480
Speaker 1: the neutron decays into a proton because they assume it

959
00:51:34,600 --> 00:51:37,600
Speaker 1: always decays into a proton. Now the bottle folks, they

960
00:51:37,640 --> 00:51:41,120
Speaker 1: will see that neutron disappear because they're counting the neutrons themselves.

961
00:51:41,360 --> 00:51:43,840
Speaker 1: So if the neutrons sometimes decay into something which is

962
00:51:44,000 --> 00:51:47,520
Speaker 1: not a proton, then these two groups will get different numbers.

963
00:51:48,040 --> 00:51:50,120
Speaker 1: So this is fun idea out there about how maybe

964
00:51:50,200 --> 00:51:54,200
Speaker 1: neutrons will sometimes decay into dark matter instead of into protons.

965
00:51:54,520 --> 00:51:57,760
Speaker 1: That is really cool. I love that when in science,

966
00:51:57,840 --> 00:52:01,160
Speaker 1: like if you get an unexpected result bolt or something

967
00:52:01,200 --> 00:52:03,520
Speaker 1: that seems like a mistake, it could actually lead you

968
00:52:03,600 --> 00:52:07,200
Speaker 1: to an even bigger, even more interesting discovery. And there's

969
00:52:07,239 --> 00:52:09,200
Speaker 1: so many times in the history of science when you

970
00:52:09,280 --> 00:52:11,480
Speaker 1: do that, When people do experiments, they think just like

971
00:52:11,840 --> 00:52:14,600
Speaker 1: wrapping up everything, tying up the loose ends. We're pretty

972
00:52:14,600 --> 00:52:16,680
Speaker 1: sure we understand what we're gonna see. And then there's

973
00:52:16,680 --> 00:52:19,520
Speaker 1: a discrepancy and it's persistent and it won't go away,

974
00:52:19,760 --> 00:52:22,680
Speaker 1: and sometimes you tug on that thread and it unravels

975
00:52:22,800 --> 00:52:25,360
Speaker 1: like everything we thought we knew about the universe. You know,

976
00:52:25,480 --> 00:52:28,400
Speaker 1: the whole discovery of quantum mechanics was from people like

977
00:52:28,480 --> 00:52:30,680
Speaker 1: m that's weird. You don't really understand what's going on

978
00:52:30,800 --> 00:52:34,440
Speaker 1: with the photoelectric effect. So these little discrepancies are very important.

979
00:52:34,440 --> 00:52:37,560
Speaker 1: They're very powerful ways to test your assumptions and to

980
00:52:37,800 --> 00:52:40,680
Speaker 1: maybe get a clue that there's something new going on

981
00:52:40,960 --> 00:52:43,200
Speaker 1: in the universe we don't know. And the dark matter

982
00:52:43,280 --> 00:52:46,120
Speaker 1: idea is just sort of like a category of possibilities.

983
00:52:46,520 --> 00:52:48,960
Speaker 1: The specific theory that was bounced around for a few

984
00:52:49,040 --> 00:52:51,440
Speaker 1: years about the neutrons decay in the dark matter doesn't

985
00:52:51,520 --> 00:52:53,960
Speaker 1: look like it works. They made this very specific prediction

986
00:52:54,239 --> 00:52:56,200
Speaker 1: that it would decay into a new state, and in

987
00:52:56,360 --> 00:52:58,640
Speaker 1: that state, we decay into dark matter, and along the

988
00:52:58,680 --> 00:53:00,520
Speaker 1: way it would make a tiny little lash, a very

989
00:53:00,560 --> 00:53:03,200
Speaker 1: specific light. And so the bottle folks looked for this

990
00:53:03,320 --> 00:53:05,080
Speaker 1: flash of light, but they didn't see it. But that

991
00:53:05,120 --> 00:53:07,080
Speaker 1: doesn't mean that it's wrong. There might be some other

992
00:53:07,280 --> 00:53:10,479
Speaker 1: explanation in the same vein the neutrons could be turning

993
00:53:10,520 --> 00:53:12,680
Speaker 1: into something else. We don't expect a new kind of

994
00:53:12,800 --> 00:53:15,879
Speaker 1: dark matter or even something else weirder, So, are are

995
00:53:16,160 --> 00:53:19,400
Speaker 1: they looking into new experiments that they could potentially do

996
00:53:19,600 --> 00:53:22,440
Speaker 1: to sort of find out what's going on here exactly?

997
00:53:22,440 --> 00:53:24,680
Speaker 1: They're trying to develop like a third way to measure

998
00:53:24,719 --> 00:53:26,919
Speaker 1: the neutron lifetime, because that will give us a handle.

999
00:53:26,920 --> 00:53:29,240
Speaker 1: It's like a vote, right, we develop a third, totally

1000
00:53:29,280 --> 00:53:32,239
Speaker 1: independent way with different assumptions than either the first two.

1001
00:53:32,360 --> 00:53:34,440
Speaker 1: It will tell us which of those first two is

1002
00:53:34,520 --> 00:53:37,160
Speaker 1: correct and which one is not. Actually measuring the neutron

1003
00:53:37,239 --> 00:53:39,399
Speaker 1: lifetime the way we thought it was. A third way

1004
00:53:39,480 --> 00:53:42,759
Speaker 1: to measure this is actually in space because one way

1005
00:53:42,840 --> 00:53:47,080
Speaker 1: to make neutrons is to smash protons against the Earth's atmosphere,

1006
00:53:47,160 --> 00:53:49,720
Speaker 1: which happens all the time out there in space because

1007
00:53:49,760 --> 00:53:53,200
Speaker 1: space is filled with high energy cosmic rays. Protons from

1008
00:53:53,239 --> 00:53:55,600
Speaker 1: the center of the galaxy or from other solar systems

1009
00:53:55,960 --> 00:53:59,600
Speaker 1: smashing into Earth's atmosphere, creating these showers of particles, including

1010
00:53:59,640 --> 00:54:02,359
Speaker 1: neutron on. Now, most of these neutrons then like rain

1011
00:54:02,520 --> 00:54:05,239
Speaker 1: down on the Earth's surface, and as they do, because

1012
00:54:05,239 --> 00:54:08,640
Speaker 1: they're by themselves, they're not inside atomic nuclei, they turn

1013
00:54:08,760 --> 00:54:11,839
Speaker 1: into protons. So if you can count like the number

1014
00:54:11,880 --> 00:54:14,080
Speaker 1: of neutrons created at the edge of the atmosphere with

1015
00:54:14,160 --> 00:54:17,640
Speaker 1: a number of protons you then see raining down, you

1016
00:54:17,719 --> 00:54:19,800
Speaker 1: can get a sense for how many of those neutrons

1017
00:54:19,840 --> 00:54:23,239
Speaker 1: have converted from neutrons into protons. And that's a way

1018
00:54:23,320 --> 00:54:25,520
Speaker 1: to measure the neutron lifetime. It's a bit tricky and

1019
00:54:25,520 --> 00:54:27,360
Speaker 1: it's more complicated, which is why it wasn't like the

1020
00:54:27,440 --> 00:54:30,440
Speaker 1: first option or the second option. But now we need

1021
00:54:30,480 --> 00:54:32,279
Speaker 1: a third option and we need to figure this out.

1022
00:54:32,400 --> 00:54:34,880
Speaker 1: And so people are even talking about like building probes

1023
00:54:34,920 --> 00:54:38,000
Speaker 1: that an orbit Venus, because Venus might have the perfect

1024
00:54:38,080 --> 00:54:40,960
Speaker 1: atmosphere to do this kind of experiment, because it's got

1025
00:54:41,040 --> 00:54:43,160
Speaker 1: so much C O two in it, So it's using

1026
00:54:43,200 --> 00:54:48,680
Speaker 1: a whole planet as a test tube exactly. Particle physicists

1027
00:54:48,680 --> 00:54:51,760
Speaker 1: are not content to just do experiments in one tiny

1028
00:54:51,840 --> 00:54:54,759
Speaker 1: little lab. We want to use the whole universe as

1029
00:54:54,840 --> 00:54:57,200
Speaker 1: our experiment. I see you're just trying to use your

1030
00:54:57,600 --> 00:55:02,400
Speaker 1: research budget for travel. I get it, exactly. What's this

1031
00:55:02,560 --> 00:55:05,560
Speaker 1: first class ticket to Venus? Daniel? Can you explain this charge?

1032
00:55:07,760 --> 00:55:09,719
Speaker 1: But this is something that's really important, you know, not

1033
00:55:09,920 --> 00:55:12,720
Speaker 1: just because we want to understand what's inside the neutron

1034
00:55:12,840 --> 00:55:14,759
Speaker 1: and how does it work and is the neutron turning

1035
00:55:14,800 --> 00:55:17,640
Speaker 1: into something else? The neutron lifetime is a really important

1036
00:55:17,680 --> 00:55:21,160
Speaker 1: component of our universe. You know, in the early universe,

1037
00:55:21,280 --> 00:55:23,480
Speaker 1: neutrons were made, as we talked about, but if they

1038
00:55:23,480 --> 00:55:25,960
Speaker 1: didn't last for long enough, they couldn't get served up

1039
00:55:26,040 --> 00:55:29,200
Speaker 1: into atomic nuclei. So the length of the neutron lifetime

1040
00:55:29,280 --> 00:55:32,960
Speaker 1: sort of determines how many isotopes are made, how much

1041
00:55:33,080 --> 00:55:35,440
Speaker 1: helium is made, and so it's important to get this

1042
00:55:35,640 --> 00:55:38,560
Speaker 1: number right. You know. They determines like the hydrogen to

1043
00:55:38,640 --> 00:55:41,960
Speaker 1: helium ratio that's made during the Big Bang, but also

1044
00:55:42,040 --> 00:55:45,520
Speaker 1: determines like how long stars will live, because the more

1045
00:55:45,640 --> 00:55:49,000
Speaker 1: helium you get, the smaller and heavier the stars are

1046
00:55:49,120 --> 00:55:51,200
Speaker 1: that are made, which don't burn as long. So this

1047
00:55:51,360 --> 00:55:54,799
Speaker 1: is like a fundamental ingredient to the early universe calculations.

1048
00:55:54,840 --> 00:55:57,200
Speaker 1: It's something we really need to understand. So even a

1049
00:55:57,280 --> 00:56:01,560
Speaker 1: discrepancy of a few seconds is very important to determine

1050
00:56:01,719 --> 00:56:04,040
Speaker 1: what is causing that and what the answer is to

1051
00:56:04,160 --> 00:56:06,360
Speaker 1: this right, and it goes to really deep questions in

1052
00:56:06,440 --> 00:56:09,200
Speaker 1: particle physics about the strong force. You know, this is

1053
00:56:09,239 --> 00:56:12,200
Speaker 1: something that we can't sit down and predict very confidently.

1054
00:56:12,560 --> 00:56:15,120
Speaker 1: It takes massive calculation to try to get a sense

1055
00:56:15,440 --> 00:56:17,640
Speaker 1: for how corks talk to each other because the forces

1056
00:56:17,719 --> 00:56:20,120
Speaker 1: are so strong and so difficult to calculate with. It's

1057
00:56:20,160 --> 00:56:23,399
Speaker 1: something physicists called non perturbative, which means that we can't

1058
00:56:23,480 --> 00:56:26,520
Speaker 1: make many of our typical assumptions and simplifications when we

1059
00:56:26,640 --> 00:56:29,880
Speaker 1: do these calculations. So this is a great laboratory to

1060
00:56:30,040 --> 00:56:32,520
Speaker 1: force the universe to teach us something about how the

1061
00:56:32,600 --> 00:56:35,440
Speaker 1: strong force actually works, to force it to like tell us,

1062
00:56:35,680 --> 00:56:38,600
Speaker 1: here's how this happens. Here's the result of this calculation.

1063
00:56:38,840 --> 00:56:40,560
Speaker 1: So it's a really powerful way to try to get

1064
00:56:40,640 --> 00:56:43,640
Speaker 1: some inside how these little particles are talking to each other.

1065
00:56:43,760 --> 00:56:46,520
Speaker 1: And in the end, I got neutrons and you got neutrons.

1066
00:56:46,640 --> 00:56:48,480
Speaker 1: So this should be important to all of us. Yeah,

1067
00:56:48,520 --> 00:56:51,360
Speaker 1: it is interesting. It's such a humble particle that you

1068
00:56:51,440 --> 00:56:55,600
Speaker 1: think of this like neutral doesn't seem to have such

1069
00:56:55,640 --> 00:56:58,280
Speaker 1: a big role to play, But really it's so important

1070
00:56:58,320 --> 00:57:01,560
Speaker 1: to not only to keep us together apparently, like I

1071
00:57:01,600 --> 00:57:03,799
Speaker 1: don't want to fall apart into a bunch of protons

1072
00:57:03,920 --> 00:57:07,440
Speaker 1: and w minuses and then which turns into ghost particles

1073
00:57:07,480 --> 00:57:10,040
Speaker 1: and electrons. I want to stay me for as long

1074
00:57:10,120 --> 00:57:12,680
Speaker 1: as possible, but also just it seems like it's really

1075
00:57:12,719 --> 00:57:16,400
Speaker 1: important to understand them, to understand the universe. Yeah, and

1076
00:57:16,560 --> 00:57:19,120
Speaker 1: it's an enduring mystery. We're gonna stay tuned to figure

1077
00:57:19,120 --> 00:57:21,640
Speaker 1: out what's going on with these neutrons, how long they live,

1078
00:57:21,840 --> 00:57:24,680
Speaker 1: and whether Team Bottle or Team Beam got it right.

1079
00:57:24,960 --> 00:57:27,720
Speaker 1: This is exciting. I want to print shirts Team Bottle,

1080
00:57:27,800 --> 00:57:31,120
Speaker 1: Team Beam and see we're the dialay. Thank you everybody

1081
00:57:31,160 --> 00:57:34,120
Speaker 1: for joining us on this journey, the journey inside our

1082
00:57:34,200 --> 00:57:37,880
Speaker 1: atoms and your atoms and the universe's atoms, where tiny

1083
00:57:38,040 --> 00:57:40,840
Speaker 1: little clocks determine the fate of neutrons and the fate

1084
00:57:40,920 --> 00:57:43,760
Speaker 1: of stars. And thanks very much Katie for joining us

1085
00:57:43,840 --> 00:57:47,080
Speaker 1: on this very particular podcast. Thanks for having me, and

1086
00:57:47,160 --> 00:57:51,120
Speaker 1: good luck with your neutron soup. Flay tune in next time. Everybody,

1087
00:57:59,080 --> 00:58:01,840
Speaker 1: thanks for listening, and remember that Daniel and Jorge Explain

1088
00:58:01,920 --> 00:58:04,760
Speaker 1: the Universe is a production of I heart Radio. For

1089
00:58:04,960 --> 00:58:07,840
Speaker 1: more podcast from my heart Radio, visit the i heart

1090
00:58:07,960 --> 00:58:11,520
Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your

1091
00:58:11,600 --> 00:58:14,080
Speaker 1: favorite shows. Ye