Speaker 1: Hey, Daniel, you have an electric car, right, Yeah, I
Speaker 1: drive a Nissan Leaf these days, and last time I
Speaker 1: had a Chevy bolt, so you bolted from the bolt
Speaker 1: and to turn over a new leaf, I left it behind. Now,
Speaker 1: how much does it cost to charge up with one
Speaker 1: of those electric cars? Well, that's kind of a charged question,
Speaker 1: but usually less than ten dollars. Actually, oh wow, you
Speaker 1: only charge you ten bucks to charge your car? You
Speaker 1: go to one of those charging stations. No, I usually
Speaker 1: charge it at home where I'm in charge. You can
Speaker 1: charge ten bucks to charge your car where you're in charge,
Speaker 1: and charge it on my credit card. You should charge them.
Speaker 1: I'm positive that won't work. Hi'm for Hammo cartoonists and
Speaker 1: the creator of PhD comics. Hi, I'm Daniel. I'm a
Speaker 1: particle physicist and a professor at UC Irvine, and I
Speaker 1: actually do sell charges back to the electric company. Nice
Speaker 1: solar panels. I do have solar panels, but unfortunately the
Speaker 1: electrons I produced don't end up in my car. They
Speaker 1: have to go back to the company and then I
Speaker 1: buy fresh electrons from them. I don't have one of
Speaker 1: those massive home batteries yet. Yeah, you don't want old electrons?
Speaker 1: The cool kind of stale, right. The thing, I don't know.
Speaker 1: I've had some really vintage electrons created during the Big Bang,
Speaker 1: and they were pretty tasty. Aren't all electrons created in
Speaker 1: the Big Bang? Some of them might have been, but
Speaker 1: also electrons are being created all the time, and so
Speaker 1: some electrons might be very, very fresh, and some of
Speaker 1: them might have had many, many lives before you. Do
Speaker 1: you have like an electron summerlier that tells you the
Speaker 1: vintage of electrons? And how do you taste electrons? Do
Speaker 1: you just stick your tongue in the electrical outlet or what?
Speaker 1: What advice are we giving the public here? That's a
Speaker 1: shocking suggestion, Jorge, sticking your tongue in the outlet. I'm
Speaker 1: positive that's not a good idea. But it is an
Speaker 1: interesting philosophical question of whether you could taste the age
Speaker 1: of an electron or even somehow tell its age. We
Speaker 1: don't think so, because they're quantum particles, so they're all identical.
Speaker 1: Every electron is the same as every other electron, and
Speaker 1: so there's no way to tell if an electron is
Speaker 1: fourteen billion years old or fourteen billiseconds old. Yeah, it
Speaker 1: would be kind of rude. To ask anyways, But welcome
Speaker 1: to our podcast Daniel and Jorge Explain the Universe, a
Speaker 1: production of iHeartRadio, in which we try to be positive
Speaker 1: about all the charged questions there are about the age
Speaker 1: of the universe, how big it's been getting, and what
Speaker 1: it's been eating. We like to think about everything involved
Speaker 1: in understanding the universe, from the deep nature of the
Speaker 1: fabric of space itself, all the way up to the
Speaker 1: shape and size of the universe, and everything fascinating in between.
Speaker 1: We want to tickle the curiosity that we know is
Speaker 1: inside your mind and make you wonder at this marvelous universe.
Speaker 1: Why is it this way and not some other way.
Speaker 1: That's right because it is an electrifying universe, full of
Speaker 1: amazing things happening in it, things coming together, things being
Speaker 1: pushed apart, And we like to zap all of that
Speaker 1: knowledge into your brain so that you get a small buzz.
Speaker 1: And the electricity is one of the oldest topics that
Speaker 1: humans have been thinking about. After all, it's obviously out
Speaker 1: there in the world. You don't need a superconducting super
Speaker 1: collider in order to study electricity and magnetism. You just
Speaker 1: need to watch a rainstorm and look at lightning or
Speaker 1: zap yourself as you walk across a carpet. So humans
Speaker 1: have been aware of this strange phenomena of electricity for
Speaker 1: a long long time. And wait, wait, wait, wait, they
Speaker 1: had electricity back in the steam age. How did they
Speaker 1: power their light bulbs? You know, almost all electrical generations
Speaker 1: still uses steam. It's incredible how versatile the steam engine
Speaker 1: really is. That what the electrons are always wet. I
Speaker 1: don't know what's going on with the plumbing in your
Speaker 1: house that your electrons are wet. But that does not
Speaker 1: sound like a good combination. You know, not so much
Speaker 1: wet as steamy. I get steamy electron. Well, electricity has
Speaker 1: been something that's been tickling the minds of humans and
Speaker 1: physicists and proto physicists for a long long time, you know,
Speaker 1: watching a rainstorm and wondering like wow, what is that crazy?
Speaker 1: Zapping all the way up to Benjamin Franklin trying to understand,
Speaker 1: like what's going on. It's been something we've been working
Speaker 1: on for a long time. We've made a lot of progress,
Speaker 1: and yet there's still really basic questions about how it works.
Speaker 1: You know, the origin of the word electricity, Like I
Speaker 1: wonder when humans started to think of electricity as electricity
Speaker 1: because I imagine, you know, for millions of years we
Speaker 1: saw lightning, but we didn't think it was anything different
Speaker 1: other than light or you know, strips of light. Yeah.
Speaker 1: I think there's a long history of crazy ideas to
Speaker 1: explain what we see out there, and it wasn't until
Speaker 1: a few hundred years ago that people trying to be
Speaker 1: sort of systematic about it and come up with like
Speaker 1: something you could describe as a theory to explain what
Speaker 1: was going on. You know, before that we had basically
Speaker 1: mythology zoos throwing lightning bolts and this kind of stuff.
Speaker 1: I see, so Zoos was the first electric company. I
Speaker 1: wonder if zeus charge for lightning bolts, right, I don't know.
Speaker 1: They are pretty spectacular to look at. But anyways, electricity
Speaker 1: is one of those old subjects that humans have been
Speaker 1: thinking about and wondering about, and apparently it's still something
Speaker 1: that we wonder about today. That's right. We have graduated
Speaker 1: from thinking about electricity as the product of an angry
Speaker 1: god to thinking about it as a strange, invisible fluid
Speaker 1: that flows through matter, to modern ideas that electricity is
Speaker 1: carried by tiny, little discrete charged particles, each of which
Speaker 1: carry this strange quantum label of electric charge. It doesn't
Speaker 1: sound like we've progressed much there from saying electricity is
Speaker 1: something that God throws down from the sky to something
Speaker 1: that little tiny particles have. Well, maybe emotionally we've progressed.
Speaker 1: You know, we don't think electrons are angry as Zeus was.
Speaker 1: So you know, maybe it's just a calmer theory of
Speaker 1: the universe, or maybe you just don't know if your
Speaker 1: electrons are mad at you. It could be, especially if
Speaker 1: you ask them their age. But that means that all
Speaker 1: electrons in the universe would have to be mad at you.
Speaker 1: That's like a whole universe filled with screaming, mad electrons.
Speaker 1: That's kind of terrifying. Maybe it's only the ones that
Speaker 1: you use for your car. They don't like where you're going.
Speaker 1: The ones we put to work, Yeah, exactly, just because
Speaker 1: you don't want to walk, Daniel, even if I'm walking,
Speaker 1: that uses electrons. Right, there's electrons in everything. Anytime you
Speaker 1: do some work, that's going to be electrons involved. So
Speaker 1: that's why the electron labor union is so powerful. I
Speaker 1: wonder how they hold together. But there is a lot
Speaker 1: we don't understand about the universe. And it's kind of
Speaker 1: surprising to think about the idea that there are things
Speaker 1: we don't understand about electricity. I feel like the electricity
Speaker 1: is something that we use every day. I mean, we're
Speaker 1: using it right now to record this, and also everyone
Speaker 1: is using this to listen to this podcast, and yet
Speaker 1: there are things we still don't know about it. Yeah. Well,
Speaker 1: you don't actually have to understand the universe in order
Speaker 1: to use it, right. You took advantage of gravity holding
Speaker 1: you under the earth surface long before anybody had any
Speaker 1: understanding of gravity, and even four hundreds of years when
Speaker 1: we had a pretty deep misunderstanding of gravity. So it's
Speaker 1: just sort of part of the process of science to
Speaker 1: develop these descriptions of what we see, try to explain them,
Speaker 1: and then refine them as time goes on. There will
Speaker 1: always be open questions things we don't understand. What I
Speaker 1: hope that listeners appreciate is that some of these questions,
Speaker 1: some of these things we still don't understand, are really
Speaker 1: pretty basic and have to do fundamentally with the nature
Speaker 1: of electricity. What is it anyway? Yeah, And so today
Speaker 1: on the program, we'll be tackling Could there be particles
Speaker 1: with different electric charges? That's right. We know about a
Speaker 1: few different kinds of particles with a few different kinds
Speaker 1: of electric charges. But the curious person always wonders, like, well,
Speaker 1: why is that? It? Is there more on the list?
Speaker 1: Is the universe capable of doing other things? And it
Speaker 1: just isn't? Or are there other particles out there with
Speaker 1: really weird electric charges? Yeah? I guess when we say
Speaker 1: different electric charges, we mean different charges than the electron, right, Like,
Speaker 1: could there be a particle out there with a charge
Speaker 1: that's not the same as the electron? Yeah, we actually
Speaker 1: do have a few examples of that, right, Like quarks
Speaker 1: have strange charges like two thirds and minus one third,
Speaker 1: and the electron is this charge negative one. But it's
Speaker 1: interesting to think about, like could there be particle with
Speaker 1: charges of like one millionth or one billionth or like
Speaker 1: pi or other strange numbers. There seems to be like
Speaker 1: a pattern to the electric charges, or they seem to
Speaker 1: prefer these sort of discrete units, But we don't really
Speaker 1: understand why that is. Oh, I mean we're asking today
Speaker 1: whether you can have a particle with like point zero
Speaker 1: zero zero one of the charge of the electron. Yeah,
Speaker 1: is that possible to do those particles exist? What would
Speaker 1: it mean for the universe if they did or they didn't?
Speaker 1: But you said that, we know about particles that have
Speaker 1: one third of the charge of the electron. That's a
Speaker 1: quart or some of the courts. That's right, Some of
Speaker 1: the quarks have charged one third, and some of the
Speaker 1: quirks have charged two third. Basically, every particle we've ever
Speaker 1: seen either has zero charge or some multiple of one
Speaker 1: third of the electrons charge. Nicee. So today we're asking
Speaker 1: if you can go smaller than that? Could there be
Speaker 1: particles with less than a third of the electron charge? Yeah?
Speaker 1: One fifth, one ninth, one billionth even are there limits?
Speaker 1: Is there a rule that prevents a particle from having
Speaker 1: some super tiny electric charge but not zero? And I
Speaker 1: assume that's not a question with a small answer, and
Speaker 1: maybe even answer that will shock us. That's right, it's
Speaker 1: a small question with big consequences for the philosophy of
Speaker 1: electric charges. Was usual. We were wondering how many people
Speaker 1: out there had thought about this question or wondered whether
Speaker 1: particles can have tiny electric charges. Thank you very much
Speaker 1: to our list of volunteers who answer these questions for
Speaker 1: everybody else's enjoyment and education. If you would like to
Speaker 1: contribute to your voice to this segment, please don't be shy.
Speaker 1: We don't describe. We let everybody participate. Right to me
Speaker 1: to questions at Daniel and Jorge dot com. So think
Speaker 1: about it for a second. Have you heard or think
Speaker 1: that electron can have tiny electric charges? Here's what people
Speaker 1: had to say. Yep, why not. I will accept particles
Speaker 1: of any coolure. I'm sure there's no discriminating against fractional
Speaker 1: electric charges. I would guess that particles with fractional electrical
Speaker 1: charges would be possible, given that in chemistry they have certeometry,
Speaker 1: and so it maybe does not real out the fact
Speaker 1: that this could be the same for sometime a particles.
Speaker 1: I have heard health spin as a quantum property, but
Speaker 1: never health electrical charge. So I will say no, But
Speaker 1: since you are asking it, maybe yes, my guess would
Speaker 1: be probably. I'm sure there's a law physics it says no,
Speaker 1: you have to be a plus or minus or no charge.
Speaker 1: But I don't see why you couldn't have a fractional charge.
Speaker 1: I suppose, so, yeah, I think that is the case. Today.
Speaker 1: I think we have quarks with like one third charge
Speaker 1: or two thirds charge, And I think the actual charge
Speaker 1: of an electron is some crazy fractional number and we've
Speaker 1: just chosen to assign it the value of one for convenience.
Speaker 1: So yeah, I think that's possible. Well, isn't charges caused
Speaker 1: by particles like electrons considered particles? Am I getting that wrong?
Speaker 1: I'm guessing no. Well, I'm going to walk into the
Speaker 1: obvious trap here and say that I think no particles
Speaker 1: cannot have tiny fractional electric charges. I think that an
Speaker 1: electric charge is either present, positive or negative or absent,
Speaker 1: and is an indivisible quality. I'm hoping, of course, that,
Speaker 1: true to the nature of this podcast, this obvious trap
Speaker 1: will turn out by the end of the podcast to
Speaker 1: have been an a double bluff and vindicate mind ignorance.
Speaker 1: All right, A lot of people said yes, because, of course,
Speaker 1: maybe we asked the question wrong. I think that most
Speaker 1: people don't even imagine the existence of like particles with
Speaker 1: one millions of the electric charge. Yeah, that's not something
Speaker 1: nice they open night usually wondering about. I mean, maybe
Speaker 1: one thousands, but not a million. There's some limit there.
Speaker 1: You're like, one thousands is reasonable. One millions. This crazy. Yeah, yes,
Speaker 1: that is what I think about at night. Well, you know,
Speaker 1: a way to explore the universe is just to try
Speaker 1: to be creative, to think about, like what assumptions are
Speaker 1: we making because we've only seen certain examples, what conclusions
Speaker 1: are we drawing because we've only seen a subset of
Speaker 1: what the universe can actually do. So sometimes it takes
Speaker 1: a little bit of creativity to like break out of
Speaker 1: the box we've been living in and wonder what could
Speaker 1: be outside that box. Sometimes we don't even realize the
Speaker 1: boxes that we are in. So I love this question
Speaker 1: precisely because a lot of people are like, huh, that's interesting.
Speaker 1: I never even consider that there could be other kinds
Speaker 1: of particles with weird electric charges in them. And that's
Speaker 1: what makes it exciting, because that's the best moment in physics,
Speaker 1: when we realize we've been overlooking something and maybe it
Speaker 1: shows us something new about the real universe out there.
Speaker 1: I wonder if maybe what we're asking here really is like,
Speaker 1: are there maybe particles with weird electric charges that we
Speaker 1: didn't know how weird electric charges? Is that kind of
Speaker 1: what we're asking, like, maybe there are things there are
Speaker 1: particles out there which just haven't seen them or known
Speaker 1: about them, that actually have these weird charges we just
Speaker 1: haven't noticed. Yeah, exactly. One possibility is that there's a
Speaker 1: new kind of particle out there with weird electric charges
Speaker 1: we just haven't noticed yet. The other possibility is that
Speaker 1: maybe some of the particles we do know don't actually
Speaker 1: have zero electric charge, they have very very very very
Speaker 1: small electric charges. All right, well, let's jump into this topic, Daniel.
Speaker 1: Let's start with the basics. What is an electric charge? Well,
Speaker 1: we don't really know. All thanks for joining us. See
Speaker 1: you next time. It's fun to joke about that, because
Speaker 1: that really is the answer. We don't actually know what
Speaker 1: an electric charge is physically. It's part of our description
Speaker 1: of what we see happen in the universe. So we
Speaker 1: notice that some particles that accelerated if you put them
Speaker 1: in an electric field, and other particles don't. Right, And
Speaker 1: we even have an equation that describes it. Right. Force
Speaker 1: is equal to charge times the field strength. So if
Speaker 1: a particle is accelerated when you put it in an
Speaker 1: electric field, we say that particle has charge. If a
Speaker 1: particle ignores the electric field, we say the particle has
Speaker 1: no charge. And the bigger the charge of the particle,
Speaker 1: the greater the force that it feels. But it's just
Speaker 1: sort of like our description of what we see. We
Speaker 1: put this into our mathematical story about the universe. That
Speaker 1: doesn't mean we know like what it is, right, But
Speaker 1: it's even more confusing than that, because it's kind of like,
Speaker 1: how do you define an electric field? Isn't an electric
Speaker 1: field defined as how the or this change on a
Speaker 1: particle that has charge? Yeah, exactly right. We say the
Speaker 1: fields are generated by charged particles. We don't ever even
Speaker 1: see the fields themselves, right, you can't observe a field.
Speaker 1: The only thing you can observe is the field pushing
Speaker 1: on particles. So if you want to get down to
Speaker 1: the nitty gritty, what do we actually see is that
Speaker 1: some particles push on each other, and we have this
Speaker 1: intermediate thing we call a field, which allows particles that
Speaker 1: are far away from each other to push on each other.
Speaker 1: But fundamentally, we say, some particles push on each other
Speaker 1: and some particles pull on each other, and the charges
Speaker 1: in the fields. It's just sort of like our mathematical
Speaker 1: story of what's happening there that to describe what we see.
Speaker 1: So maybe you would define a charge more accurately. As
Speaker 1: you know, if you have an electron here and an
Speaker 1: electron there, they're going to push against each other, and
Speaker 1: that push sort of depends on this thing that you
Speaker 1: call a charge. Yeah, you can put a label on
Speaker 1: every kind of particle and that label tells you how
Speaker 1: to predict whether the particle will be pushed by another
Speaker 1: particle or it's field equivalently, and that works, and it
Speaker 1: works really, really really well. It works incredibly well. It's
Speaker 1: one of the best tested theories we have in physics.
Speaker 1: We can do pages and pages of calculations to predict
Speaker 1: how electrons will push on each other and how they
Speaker 1: will shoot photons at each other, and we can do
Speaker 1: experiments to test those predictions, and the experiment and the
Speaker 1: prediction agree to like eight or nine decimal places. It's
Speaker 1: really extraordinary how accurate it is. And so you look
Speaker 1: at that theory and you're like, hm, well, if it's
Speaker 1: so accurate, maybe it's really describing what happens in the universe.
Speaker 1: Maybe this thing we invented, this idea of charge, is
Speaker 1: a property of the particle itself, not just part of
Speaker 1: our story about the particle. Right, it's sort of like
Speaker 1: mass is for gravity, Right Like, if you have two
Speaker 1: particles out there in space, they're going to attract each
Speaker 1: other depending on this thing about them called mass, And
Speaker 1: that's kind of the same for charge, right Like, if
Speaker 1: you have two particles, they're going to either attract each
Speaker 1: other or repel each other by a certain amount, pending
Speaker 1: on whether they have this thing called charge. Yes, excellent, exactly,
Speaker 1: And in particle physics we generalize this concept of charge.
Speaker 1: Do not just refer to electromagnetism, as you say. You
Speaker 1: can think about gravity in terms of gravitational charges or masses,
Speaker 1: and you can think about the strong force in terms
Speaker 1: of strong nuclear charges on quarks. Those are even more
Speaker 1: complicated because instead of having two values like plus or minus,
Speaker 1: have three values red, green, and blue. The weak force
Speaker 1: also has a kind of charge that we call weak hypercharge.
Speaker 1: So in a more general sense, charge tells you whether
Speaker 1: a particle feels a force. Like the electron has an
Speaker 1: electric charge, but it has no strong nuclear charge. It
Speaker 1: doesn't feel the strong nuclear force. A quark has both
Speaker 1: an electric charge and a strong nuclear charge, and so
Speaker 1: it feels both forces. So really, charge in general is
Speaker 1: a label about saying whether or not a particle feels
Speaker 1: that force, and it's something philosophically we like attached to
Speaker 1: the particle. We say, this is a property of this particle.
Speaker 1: The electron has the charge physically, I don't really know
Speaker 1: what that means, like where in the electron is it.
Speaker 1: It's just sort of this like ineffable quantum label we
Speaker 1: attached to it. We don't really know where it comes from,
Speaker 1: like what generates the actual charge itself? Well, I think
Speaker 1: in quantum theory and correct me if I'm wrong. But
Speaker 1: it also because it sort of has to do whether
Speaker 1: a particle interacts with certain quantum fields or done right,
Speaker 1: Like maybe that's another way to define it. If the
Speaker 1: electron doesn't interact with the strong force field, then it
Speaker 1: just doesn't have a strong charge. Yeah, I think that's
Speaker 1: another way of saying the same thing. You can think
Speaker 1: about all these quantum pictures of the world either in
Speaker 1: terms of particles that are pushing on each other or
Speaker 1: in terms of fields, because remember, these particles are actually
Speaker 1: just little wiggles in quantum fields, and those fields can
Speaker 1: sometimes talk to each other. So, for example, the electromagnetic
Speaker 1: field for which the photon is a particle can interact
Speaker 1: with or talk to any field that has charges. So
Speaker 1: the electron field of which the electron is the wiggle
Speaker 1: is the particle, right, that will interact with the electromagnetic field,
Speaker 1: and so will the field of the w boson because
Speaker 1: it has electric charge. So as you say, the fields
Speaker 1: that interact with a certain force, we say their particles
Speaker 1: have that charge, and the fields that don't, we say
Speaker 1: the particles don't have that charge. So, for example, the
Speaker 1: neutrino field, neutrinos have no electric charge. Neutrino fields and
Speaker 1: electromagnetic fields totally ignore each other. Right, So then maybe
Speaker 1: you can define charges being like whether or not auto
Speaker 1: particle interacts with the electromagnetic field. Yeah, for the electric charge,
Speaker 1: And in terms of like particle theory, they often talk
Speaker 1: about it as coupling. The electric charge is the way
Speaker 1: that the photon field couples to the electron field. How
Speaker 1: those two fields sort of like let energy slide back
Speaker 1: and forth between them. I feel like we're getting a
Speaker 1: little steaming out there. Are we back to talking about
Speaker 1: steamia not steaming a not safe for workway? You know,
Speaker 1: we're just talking about connections. We're just talking about energy
Speaker 1: sliding from one kind of feel to the other. All right, well,
Speaker 1: what sounds like we kind of have a definition of
Speaker 1: what charge is. We just don't know where it comes
Speaker 1: from kind of right, That's the thing, like, we don't
Speaker 1: know why some particles interact with the electropicnet feels and
Speaker 1: why some don't. That's right. We have a very effective
Speaker 1: description of it, but we don't know why some particles
Speaker 1: have it, what the rules are for what charges you
Speaker 1: are allowed to have, and where it comes from at all. Yeah,
Speaker 1: I guess some particles just have that spark and others
Speaker 1: some particles just have a positive attitude. All right, Well,
Speaker 1: let's get into a little bit of the history of
Speaker 1: this idea of an electric charge. Where did it come from?
Speaker 1: How did humans start to figure this out? And then
Speaker 1: let's get into the bigger question of whether electrons or
Speaker 1: things with electrical charge can have tiny, almost imperceptible charges.
Speaker 1: But first let's take a quick break or I we're
Speaker 1: talking about charges, and we're charging ahead here with this topic,
Speaker 1: talking about whether electrons or charged particles that have the
Speaker 1: fuel electricity can have electrical charges that maybe have been
Speaker 1: escaping our notice for thousands of years. So Daniel, maybe
Speaker 1: step us through here a little bit on the history
Speaker 1: of charges. When did we start noticing that some things
Speaker 1: have electrical charge? So we certainly had noticed the properties
Speaker 1: of electricity for a long long time, right, static electricity
Speaker 1: and lightning, these are things everybody was aware of, and
Speaker 1: until around the mid seventeen hundreds, the idea to explain
Speaker 1: these things was dominated by concepts like effluvium or this
Speaker 1: basically this two fluid theory of electricity and magnetism. It
Speaker 1: was like this invisible fluid that flowed through objects, two
Speaker 1: different kinds of invisible liquids flowing through objects, one positive,
Speaker 1: one negative, that could cancel each other out right, Because
Speaker 1: as you said, I imagine that this is something we've
Speaker 1: noticed for maybe hundreds of thousands of years. Imagine, you know,
Speaker 1: even caveman would get you know, static electricity in their
Speaker 1: hair would stand up right, But for them it was
Speaker 1: probably just you know, magic, or they had no way
Speaker 1: to grant that there would be a reason for that exactly.
Speaker 1: And the process of science is want to try and
Speaker 1: develop like an explanation for these things. How can we
Speaker 1: unify different phenomena that we see, the static electricity in
Speaker 1: your hair and the lightning in the sky, Which of
Speaker 1: these things are related and which of these are totally
Speaker 1: different phenomena. So that's the process of physics, right sorting
Speaker 1: out all the phenomena we see and trying to coalesce them,
Speaker 1: boil them down into a few simple explanations, and try
Speaker 1: to find the relationship between those to give, like, you know,
Speaker 1: a single description of everything that's happening. And so this
Speaker 1: really is an ancient process. It's a great example of
Speaker 1: the whole process of physics of trying to coalesce many
Speaker 1: different things down into one explanation. But I think you're
Speaker 1: saying that maybe we did have sort of some idea
Speaker 1: that it was something that flowed between things, right, Yeah,
Speaker 1: it was sort of considered to be a liquid. We
Speaker 1: didn't have the idea of particles yet. It wasn't until
Speaker 1: you know, the late eighteen hundreds when J. J. Thompson
Speaker 1: discovered the electron that we thought of it is like
Speaker 1: isolated to a little particle. It was sort of more
Speaker 1: similar to early concepts of heat. You know, this liquid
Speaker 1: that flowed between things. And it's really fascinating because the
Speaker 1: original idea was of two liquids, one positive and one negative,
Speaker 1: which could flow between things, and they could cancel each
Speaker 1: other out. It was mostly trying to explain like electrical
Speaker 1: attraction and repulsion and that theory. You know, it sounds
Speaker 1: right because we know that there are protons and there
Speaker 1: are electrons, which is actually not quite right because the
Speaker 1: protons don't really flow. Right. What happens with electricity in objects,
Speaker 1: It say it's the electrons that are moving. And so
Speaker 1: it was actually in the mid seventeen hundreds with Ben Franklin,
Speaker 1: came up with the one fluid theory of electricity. Basically,
Speaker 1: there's just one kind of thing that's moving around. Now
Speaker 1: we know, of course those are electrons, and that's a
Speaker 1: more accurate description of what's actually happening, but it sort
Speaker 1: of ignores the protons and the positive charge. So it's
Speaker 1: sort of fascinating from that point of view. Historically, I
Speaker 1: think you're saying that maybe like our early ideas about
Speaker 1: electricity was that it was sort of like a fluid.
Speaker 1: I guess I'm sort of like magical fluid in a way,
Speaker 1: and that maybe at first we thought there were positive
Speaker 1: fluids negative fluids, but more actually, when you see electricity
Speaker 1: on an everyday basis, it's usually the negative electric charges
Speaker 1: that are flowing around exactly in immaterial it's the electrons
Speaker 1: that are moving. The protons are usually in the crystal
Speaker 1: and can't really move very well. The nuclei don't flow,
Speaker 1: so it really is the electrons that are moving. And
Speaker 1: Ben Franklin did all these experiments with cloths and glass rods,
Speaker 1: and of course his famous experiments with lightning. He's one
Speaker 1: of the first people to try to explain all these
Speaker 1: things in terms of a single phenomena. Did he use
Speaker 1: hundred dollars bills? Also? He was all about the Benjamin's
Speaker 1: for sure. But then it was in the late eighteen
Speaker 1: hundreds that J. Thompson did his experiments with cathode ray
Speaker 1: tubes and he showed that there were these tiny little
Speaker 1: dots of matter that carried charge with them. He showed
Speaker 1: they could be deflected by electric fields. We have a
Speaker 1: whole episode about the discovery of the electron which want
Speaker 1: to dig into the details of that one. But it
Speaker 1: was a really interesting moment because he showed where the
Speaker 1: charge was. It went from being like this weird invisible
Speaker 1: not quite magic but imperceptible fluid, to being isolated to
Speaker 1: these little bits. There was something out there that was
Speaker 1: carrying these charges. We'd like identified a little bit of matter.
Speaker 1: It had mass and it had electric charge to it,
Speaker 1: So that made it like concrete in a new way.
Speaker 1: So wait, he could actually see individual electrons. How do
Speaker 1: you see an electron? Well, he couldn't see an individual electron,
Speaker 1: but he could see them land on a screen in
Speaker 1: his cathode ray You know, cathode ray tube is basically
Speaker 1: the way TVs used to work. They have a little
Speaker 1: gun of electrons that would shoot at the screen, and
Speaker 1: you would have fields that bend them, so they would
Speaker 1: shoot at different places at the screen it would scan across.
Speaker 1: And that's not very different from his original setup where
Speaker 1: he had a little hot bit of metal that boiled
Speaker 1: off electrons and then they were accelerated by a field
Speaker 1: and then bent by another field. So what he showed
Speaker 1: was that you could bend their path using fields, which
Speaker 1: meant that they were carrying the charge, and he could
Speaker 1: change where they landed by changing those fields. A really
Speaker 1: clever set of experiments. Right, But I wonder if he
Speaker 1: thought maybe there were just droplets of this fluid right,
Speaker 1: Like he maybe didn't think of them as particles necessarily,
Speaker 1: did he? Because the quantum idea wasn't around yet, that's right.
Speaker 1: But he actually is the one who came up with
Speaker 1: this concept that these things were all isolated on these
Speaker 1: tiny little dots. He didn't use the word particle. He
Speaker 1: invented this other word called the corpuscule, which he hoped
Speaker 1: was going to take off and that we'd all be
Speaker 1: corpuscular physicists by now. But fortunately that name was dropped
Speaker 1: later by other people. But he definitely identified these things
Speaker 1: as tiny little dots with mass and with charge bundled
Speaker 1: together into the same physical location. It's really the first
Speaker 1: moment where we started putting these labels on tiny dots
Speaker 1: of matter, sort of the invention of the concept of
Speaker 1: a particle. There. Did he call it an electron or
Speaker 1: when did the name come into use? He definitely called
Speaker 1: them corpuscules. The name electron came later, which I don't know.
Speaker 1: I'd prefer the word electron two corpuscule. It's really amountable.
Speaker 1: And it was Milliken a few decades later who did
Speaker 1: his famous oil drop experiments where he showed that the
Speaker 1: charge is discreete that you couldn't have like one and
Speaker 1: a half charges or two point seven charges but you
Speaker 1: could have like one, two, or three these very precise
Speaker 1: experiments that were balancing various forces and showing that they
Speaker 1: were integer quantities of them. So at that point we
Speaker 1: knew that charge was a thing, that it was attached
Speaker 1: to these tiny little particles, and that their charges were discrete.
Speaker 1: You didn't have like some particles running around with one
Speaker 1: point two seven charges and other ones with zero point
Speaker 1: eight nine. You either had one electron or two electrons
Speaker 1: or three electrons. You know, this is around the same
Speaker 1: time that quantum mechanics was being developed, when we had
Speaker 1: the understanding that light was packets of photons. You couldn't
Speaker 1: have like one point two of them. So the whole
Speaker 1: idea of discretization was sort of taking over physics. Sounds indiscreet,
Speaker 1: but I guess my question is how did Milliken figure
Speaker 1: this out? I mean, you're talking about the early nineteen hundreds.
Speaker 1: How did they have experiments that can measure things down
Speaker 1: to the one electron level? This is a really hard
Speaker 1: experiment to do. He took little drops of oil and
Speaker 1: he sprayed them out of a little sprayer, which basically
Speaker 1: strips them of some electrons, which basically ionizes them, and
Speaker 1: so now they have electric charge, and let them fall
Speaker 1: through this little chamber until they reached terminal velocity, and
Speaker 1: then he turned on electric field to try to make
Speaker 1: them levitate, and by tweaking the electric field, he could
Speaker 1: find exactly the right force he needed to balance the
Speaker 1: downward going velocity. You could make these particles float. Essentially,
Speaker 1: and what he noticed was needed a certain field or
Speaker 1: like twice that field or three times that field, which
Speaker 1: he hypothesized told him like how much each drop had
Speaker 1: been ionized. So essentially he was measuring like how much
Speaker 1: electric force you needed to levitate these drops, and he
Speaker 1: noticed that it always came intoger quantities, So he wasn't
Speaker 1: studying individual electrons. You couldn't see individual electrons, but he
Speaker 1: was studying the overall electric charge of these little drops
Speaker 1: of oil. But that sort of only works if the
Speaker 1: each drop is the size of one electron, right, Like
Speaker 1: if you have a whole cluster of things with electrons,
Speaker 1: would you still notice that kind of discrete electric field. Yeah,
Speaker 1: you can have a whole oil drop. But what he's
Speaker 1: measuring is the ionization of that drop, like essentially, how
Speaker 1: many non neutral particles are in that drop, Because that's
Speaker 1: what's going to affect the force that the drop feels
Speaker 1: when you put it in an electric field. So he
Speaker 1: was noticing that you could ionize these drops by one unit,
Speaker 1: or two units, or seven units, but not by three
Speaker 1: point two units. Interesting. All right, well, I think that's
Speaker 1: kind of the general history of electrons, right, And that's
Speaker 1: where the idea of the electron took off, right as
Speaker 1: a discrete thing. And then the rest is history. The
Speaker 1: rest is history. And now we regularly produce electrons and
Speaker 1: ar collider and study them in gory detail. In the
Speaker 1: mid nineteen fifties, we had quantum electrodynamics, this theory of
Speaker 1: photons and electrons as oscillating quantum fields, which is basically
Speaker 1: the modern story of electromagnetism. All right, well, let's get
Speaker 1: to our question of whether electrons or other particles can
Speaker 1: have charges that are smaller than one third of the
Speaker 1: charge of an electron. I guess, Daniel, why are we
Speaker 1: asking this question? Or I guess what do we know
Speaker 1: about charge in general? So what we know is that
Speaker 1: electrons have charged minus one, which is just something we assigned, right,
Speaker 1: We could have given electrons any charge. It's really just
Speaker 1: totally arbitrary, and that protons have the opposite charge. Protons,
Speaker 1: of course, are made of quarks, and those quarks have
Speaker 1: the weirdest charges we know. They have charges like plus
Speaker 1: or minus two thirds or plus or minus one third.
Speaker 1: There are also particles out there neutrinos that have charged zero.
Speaker 1: So all the fundamental particles that we know about have
Speaker 1: charges zero one thirds, two thirds, or like the electron,
Speaker 1: they have effectively charge one. These units are arbitrary, but
Speaker 1: everything seems to have a charge that a multiple of
Speaker 1: one third of the electric charge. That seems to be
Speaker 1: the minimum charge out there. Of the zero, of course,
Speaker 1: which you can consider still a multiple of one third.
Speaker 1: There's no particles out there that we've seen that have
Speaker 1: charged like two sevenths or fourteen ninety firsts or you know,
Speaker 1: pie times the electron. I guess, just to be clear,
Speaker 1: there's only four particles that we know about that have
Speaker 1: electric charge. Is that true? Well, there are the four
Speaker 1: kinds of fermions, right, electrons, neutrinos, of quarks, and down quirks.
Speaker 1: There are also the other generations like the charm, the top,
Speaker 1: the muon the towel. Those all have the same electric
Speaker 1: charges as the base particles. So yeah, there are four
Speaker 1: kinds of fermions, and each one has a different charge. Right,
Speaker 1: So I guess what I mean is that we haven't
Speaker 1: found any other particles other than these four and their
Speaker 1: generational cousins that have electric charge, right that we The
Speaker 1: only other particle with electric charge is the W. The
Speaker 1: W is one of the first particles of the weak force,
Speaker 1: and interestingly, it also has electric chart. So there's two
Speaker 1: of those. There's the W plus and the W minus,
Speaker 1: So those sub charges plus one and minus one. Those
Speaker 1: are the only other charge particles out there. The other
Speaker 1: particles like the Higgs boson and the photon and the
Speaker 1: gluon and the z boson, all of those have zero
Speaker 1: electric charge. Wait, the W particle also has electric chart,
Speaker 1: and it's exactly the same as the electron. It's exactly
Speaker 1: the same or opposite of the electron. And that's important
Speaker 1: because the W and the electron interact with each other.
Speaker 1: For example, a W can decay to an electron and
Speaker 1: a neutrino, and that conserves electric charge. You start out
Speaker 1: with charge minus one, you end up with an electron
Speaker 1: with charge minus one and a neutrino with charge zero.
Speaker 1: So electric chart starts at minus one ends at minus one.
Speaker 1: It's conserved. That's something else really fascinating that we know
Speaker 1: about electric charge is that it can't be created or destroyed.
Speaker 1: It's always conserved in the universe. Now, is that a
Speaker 1: cool incidence that the W happens to have the exact
Speaker 1: same charges the electron? I don't think we know the
Speaker 1: answer to that. But if it didn't have exactly the
Speaker 1: same charges the electron, then it wouldn't be able to
Speaker 1: interact with the electron. Like the W had a charge
Speaker 1: of one point two, then it couldn't decay to an
Speaker 1: electron and a neutrino because charge is conserved. And so
Speaker 1: basically it would mean that it couldn't interact with our
Speaker 1: kind of matter, and then it wouldn't participate in anything
Speaker 1: that we knew about, And so it might exist in
Speaker 1: the universe but not be something we could see or
Speaker 1: interact with. Right, And so the fact that the W
Speaker 1: has the same charge as the electron is what allows
Speaker 1: it to participate in our part of the universe, and
Speaker 1: so that's the reason we know about it. So it
Speaker 1: might be that there are particles out there with weird
Speaker 1: charges that don't interact in the same way as our particles,
Speaker 1: and that's exactly what people are looking for. M I see.
Speaker 1: That's I think this gets into kind of the heart
Speaker 1: of what we're asking here today and why maybe we
Speaker 1: may have observed other particles that have different terms. Because
Speaker 1: I know we talked about before, how the idea that
Speaker 1: the proton has exactly the opposite charge of an electron.
Speaker 1: It's sort of a coincidence in the universe, and if
Speaker 1: that was any different, we wouldn't have all those things
Speaker 1: we have today like us. That's right. It's sort of
Speaker 1: explained and sort of not explained. Right, It's not explained
Speaker 1: in the sense that, in principle it could have been
Speaker 1: something else. Right. It could have been that the quarks
Speaker 1: don't have exactly one third and two thirds the charge
Speaker 1: of the electron, so when you put them together you
Speaker 1: get a proton that's not exactly the opposite charge of
Speaker 1: the electron. That could work in physics, but it's explained
Speaker 1: in the sense that that universe would be so different
Speaker 1: from ours that it's sort of impossible to even imagine
Speaker 1: what that would be like. Would be very different from
Speaker 1: the universe we experience. So to have a universe like ours,
Speaker 1: requires that balance. That doesn't mean we know why that
Speaker 1: balance exists, right, So it's a really fascinating question philosophically. Yeah,
Speaker 1: all right, Well, let's get into this question of whether
Speaker 1: charges can be different than the ones from the electron,
Speaker 1: and specifically much smaller than one third the charge of
Speaker 1: an electron, Like maybe there are particles out there with
Speaker 1: that kind of charge, we just haven't seen them. So
Speaker 1: let's get into that question. But first, let's take another
Speaker 1: quick break. All right, we're talking about charges in the universe,
Speaker 1: and Daniel were saying that, you know, the electron has
Speaker 1: a charge of negative one because that's what we gave it,
Speaker 1: and we know that the proton, which is made out
Speaker 1: of quarks, has an overall charge of plus one, and
Speaker 1: the fact that they're exactly the opposite is sort of
Speaker 1: the reason that we can't have atoms and things like that. Right,
Speaker 1: if it was any different, what would happen If it
Speaker 1: was any different, then you couldn't get neutral hydrogen, for example. Right,
Speaker 1: there was this moment in the universe very early on,
Speaker 1: when electrons and protons cooled down. They slowed down enough
Speaker 1: that their mutual electrical attraction action could make them warm
Speaker 1: neutral hydrogen, and the universe suddenly became transparent. Right, this
Speaker 1: is the moment when the cosmic microwave background radiation was
Speaker 1: created and flew through the universe. And neutral hydrogen is
Speaker 1: essential for basically the formation of the whole universe. It's
Speaker 1: basically what makes up the universe, neutral hydrogen. Wait, wait,
Speaker 1: why is that important? I guess if let's say the
Speaker 1: proton had like one point one the charge of an
Speaker 1: electron plus one point one, you would still get hydrogen,
Speaker 1: but the hydrogen would just have an overall charge of
Speaker 1: plus point one, wouldn't it. Yeah, you could get hydrogen,
Speaker 1: it wouldn't be neutral hydrogen. And I think that has
Speaker 1: a lot of downstream effects for how chemistry happens and
Speaker 1: how life is formed and everything else that we rely on.
Speaker 1: But yeah, I'm not an expert on chemistry and biochemistry.
Speaker 1: But you could still have a universe way with suns
Speaker 1: and planets and stuff, couldn't you. You could have a universe.
Speaker 1: And I imagine that fusion could still happen because fusion
Speaker 1: fundamentally is really just a process between proton You don't
Speaker 1: really need the electrons. Like inside the heart of stars,
Speaker 1: protons are anyway ionized to you don't really have the
Speaker 1: electrons around when you do fusion, So you can still
Speaker 1: have fusion if protons don't have exactly the opposite charge
Speaker 1: of electrons, so you can still have light in the universe. Right,
Speaker 1: that's good. Remember that electromagnetism is much stronger than gravity,
Speaker 1: So for gravity to take over and to tug things
Speaker 1: together into dense objects probably requires everything to be electrically neutral.
Speaker 1: Nothing is electrically neutral, and everything is repelling each other.
Speaker 1: Gravity might not be able to overcome that and form
Speaker 1: dense objects like planets and stars and ice cream. Well,
Speaker 1: I wonder if that's true. One you could still form them,
Speaker 1: they would just maybe be different proportions of the different elements, right,
Speaker 1: Like you know, if hydrogen was like plus point one,
Speaker 1: then maybe you could have other materials that are like
Speaker 1: negative point eight, and then you could have you know,
Speaker 1: two of these and one of these. Yeah, it might
Speaker 1: be possible to still form neutral objects. But for that
Speaker 1: to work, then the charge can't just be arbitrary. They
Speaker 1: have to be like some rational fraction of each other.
Speaker 1: You know, the proton is charged pi and the electrons
Speaker 1: charged negative one, then no, arrangement of protons and electrons
Speaker 1: will give you a neutral object. It's just impossible. But
Speaker 1: if they are a rational fraction of each other, if
Speaker 1: the proton is like five fourths or nine eighths or something,
Speaker 1: then yeah, you can have a certain relationship. You can
Speaker 1: make weird atoms out of eight protons and nine electrons
Speaker 1: or something like that, Right, And I wonder if that
Speaker 1: would be okay, right, Like, like we can have molecules
Speaker 1: in our body that have an overall charge, right, we
Speaker 1: certainly could, Like a molecule in our body can lose
Speaker 1: an electron in one of its atoms and it would
Speaker 1: still be a molecule. Like maybe I wonder if biology
Speaker 1: or nature needs neutral particles. I know that a lot
Speaker 1: of our biological processes rely on charges, right, Like our
Speaker 1: entire nervous system is basically electrically charged and uses ions.
Speaker 1: So probably things like that could function. But I think
Speaker 1: the whole structure of the universe would be very different
Speaker 1: if you had these different kind of chemicals. But even
Speaker 1: this is relying on an assumption, right, It's an assuming
Speaker 1: that you could still build something neutral so that gravity
Speaker 1: could take over. If instead charges could have any value,
Speaker 1: then there's no guarantee you could put particles together to
Speaker 1: make things that are neutral. And I think that's one
Speaker 1: of the deepest questions, like why are these particles rational
Speaker 1: fractions of each other's charge one third, two thirds, five
Speaker 1: fourths even, you know, these kinds of things instead of
Speaker 1: zero point eight seven two or irrational numbers. Yeah, I
Speaker 1: guess that's the main question we're asking today, is like,
Speaker 1: why can't that be because as far as we know,
Speaker 1: the particles that we do know about have these multiple
Speaker 1: charges of each other. Right, that's kind of the idea exactly.
Speaker 1: And so if you ask theoretical physics, like what prevents
Speaker 1: us from having particles with charge zero point oh one
Speaker 1: or zero point one seven nine two, or you know,
Speaker 1: just keep going, and the answer is nothing, like there
Speaker 1: is no theoretical prohibition against it. But that's mostly because
Speaker 1: we don't really understand where charge comes from and how
Speaker 1: these labels get us signed, and so we haven't invented
Speaker 1: rules that say you can't do it. We just haven't
Speaker 1: seen any particles like that in the universe. Right. And
Speaker 1: the weird thing I guess is that you know, an electron,
Speaker 1: it comes from the electric quantum field and a quark
Speaker 1: comes from the quantum quark field, and yet they seem
Speaker 1: to have charges that are kind of multiples of each other.
Speaker 1: That's the weird thing too about the universe, right, Yeah,
Speaker 1: that is definitely a weird thing because as far as
Speaker 1: we know, those fields are not that closely related, Like
Speaker 1: there are similarities there between the electron, the neutrino, and
Speaker 1: the quarks are either paired together in similar ways, Like
Speaker 1: the W for example, can decay to an electron and
Speaker 1: a neutrino. It can also decay to a pair of
Speaker 1: quarks because that pair of quarks have a charge difference
Speaker 1: of plus or minus one. So there's definitely relationships between them,
Speaker 1: but we don't really understand all those relationships. What this
Speaker 1: suggests is that there's some deeper relationship between the electron
Speaker 1: and the quarks than we even understand. Like maybe the
Speaker 1: electron and the quarks are all made out of some
Speaker 1: tinier little particle, and some arrangement of those little tiny particles,
Speaker 1: which each have their own electric charge, is what gives
Speaker 1: you the electron with charge one or the quark with
Speaker 1: charge minus one third, the same way that like atoms
Speaker 1: are built out of the same building blocks and you
Speaker 1: get all sorts of different behavior and overall charges and whatever.
Speaker 1: Maybe electrons and quarks and neutrinos are all built out
Speaker 1: of the same tiny little building blocks, and that would
Speaker 1: explain all the relationships between them, including this strangely fortuitous
Speaker 1: relationship of their electric charges. Maybe there are puscals out
Speaker 1: there in the universe, and maybe you are corpuscular particle,
Speaker 1: I mean, opuscular physicist. It's so much fun to say.
Speaker 1: But there are theories out there about these so called
Speaker 1: milly charged particles, particles that have really really tiny electric charges.
Speaker 1: We're talking about things down to like a thousands or
Speaker 1: less of the charge of the electron, and there are
Speaker 1: experiments out there searching for them as well. Well. I
Speaker 1: feel like there's maybe two possibilities, right, Like, there's a
Speaker 1: possibility that there is a whole new kind of particle
Speaker 1: that we don't know about that has a charge that's
Speaker 1: one thousands of the electron or you know, a point
Speaker 1: nine to infinity charge. That's one possibility, is that you
Speaker 1: have a whole new kind of particle that we hadn't
Speaker 1: seen before. And then there's the other possibility. Then maybe
Speaker 1: there are electrons out there with one point one electrical charge.
Speaker 1: So which which one are we talking about here? We're
Speaker 1: talking about both of those possibilities, but we're also talking
Speaker 1: about a third possibility. Maybe there's another kind of particle
Speaker 1: out there. They call it a para electron, and it's
Speaker 1: got plus or minus para charge. So like some whole
Speaker 1: new kind of charge the way we were talking about,
Speaker 1: like the strong force has its own charge. Now I'm
Speaker 1: badge in a new force with a new charge and
Speaker 1: a new particle with that force, and it has its
Speaker 1: own new particle, like the photon. So you have a
Speaker 1: para electron with its para charge and its para photon. If, however,
Speaker 1: that new photon and the paraphoton talk to each other
Speaker 1: a little bit, if they mix a little bit, that
Speaker 1: can exchange information a tiny bit, then that para electron
Speaker 1: would look to us as if it had a tiny
Speaker 1: electric charge. So it would really have its own parrot
Speaker 1: charge of plus or minus one, but we would see
Speaker 1: it as having a tiny electric charge because we would
Speaker 1: only capture a little bit of it through this photon
Speaker 1: para photon mixing. Wait, I don't get it. So we're
Speaker 1: imagining a whole new particle a whole new kind of force,
Speaker 1: and you're saying that maybe that new fours leaks a
Speaker 1: little bit or interacts a little bit with ours in
Speaker 1: that it's its own force. But it's sort of to us,
Speaker 1: it looks like it's like it overlaps with the electromagnetic
Speaker 1: forces that we're saying a little bit. Yeah, you've got
Speaker 1: it exactly, that's exactly right. So it has the same
Speaker 1: strength as electromagnetism, but we mostly can't see it. So
Speaker 1: we see it as if it was a tiny little
Speaker 1: version of electromagnetism, like electrons with a tiny charge. Now,
Speaker 1: why do you need this whole setup to imagine a
Speaker 1: particle with point o one charge? Can I just imagine
Speaker 1: a particle with point on one charge? You can? Theorists
Speaker 1: don't like that. I was reading some papers about that,
Speaker 1: and theorists always just dismissed that possibility as not very esthetic.
Speaker 1: I think that they want a reason why a particle
Speaker 1: would have some arbitrary, tiny little chart rather than just
Speaker 1: like putting the number in by hand. You know, often
Speaker 1: theoretical physicists don't like to add parameters to the universe
Speaker 1: that don't have an explanation, and so they look for
Speaker 1: a reason why it would have to be this way,
Speaker 1: So it's a little bit more indirect. But theoretical physicists
Speaker 1: preferred like sits better in their minds for reasons. Honestly,
Speaker 1: I don't totally understand. I see they prefer to think
Speaker 1: about it coming up with a whole new fours in
Speaker 1: a whole new particle that has a little bit of
Speaker 1: coupling with the electromagnetic force, rather than just coming up
Speaker 1: with a whole new particle that has a little bit
Speaker 1: of an electromagnetic Yeah, that's exactly right, you know. And
Speaker 1: a lot of things that happen in theoretical physics are
Speaker 1: guided by a sense of aesthetics, like what would be
Speaker 1: a pretty way for this to work mathematically? What would
Speaker 1: give us a beautiful description of the universe? And that
Speaker 1: in the end is subjective, you know. We like to
Speaker 1: think about science as objective and based in fact and
Speaker 1: making progress in lockstep as we approach the truth. But
Speaker 1: a lot of it really is also a search for
Speaker 1: beauty and elegance in the universe, and that's kind of controversial.
Speaker 1: There are some folks out there who think that's misguided.
Speaker 1: The universe doesn't have to be beautiful and other folks
Speaker 1: that think that the search for elegance and beauty in
Speaker 1: our theoretical description of the universe has led to great discoveries.
Speaker 1: So it's a very controversial approach, but anyway, it's part
Speaker 1: of the literature of milli charged particles. Now, you said
Speaker 1: this is one kind of possible millicharged particle, having this
Speaker 1: whole new particle with whole new force. But then they're
Speaker 1: the other two that I mentioned, which is like, maybe
Speaker 1: there are particles with just a little tiny bit of
Speaker 1: electric charge, or maybe like the electrons we know sometimes
Speaker 1: have a little bit or a little bit more or
Speaker 1: less electric charge. And you're saying we're looking for all
Speaker 1: of these things, or just we're only looking for the
Speaker 1: new force, new particle model, we're looking for all these things.
Speaker 1: Is a lot of different experiments searching for these things.
Speaker 1: Some people are looking for these para electrons. Other people
Speaker 1: are looking to see if maybe the neutrino doesn't have
Speaker 1: zero charge, maybe it has a tiny, tiny, tiny charge. Remember,
Speaker 1: whenever we measure something in physics, it's never exact right.
Speaker 1: You can't measure something to be exactly zero. You know,
Speaker 1: we've just set a limit on it, you can say, well,
Speaker 1: if neutrinos had a charge, it would be less than
Speaker 1: some tiny value, or we would have seen it. So
Speaker 1: people are trying to like nail that down. Is it
Speaker 1: possible that the neutrino might have a tiny little charge.
Speaker 1: There's a whole broad set of experiments looking for these things. No,
Speaker 1: I guess, maybe walk us through how do you even
Speaker 1: look for these things? So first of all, to discover
Speaker 1: one of these particles, you have to see it by itself.
Speaker 1: You need to isolate it and demonstrate that it really
Speaker 1: has its own electric charge, sort of like the way
Speaker 1: we have seen quarks inside the proton. Right, you can say, oh,
Speaker 1: maybe quarks have a charge two thirds, but until you
Speaker 1: see them operating on their own, you can't really say
Speaker 1: that you have found it. And so we try to
Speaker 1: do this in accelerators. For example, we smash protons together
Speaker 1: and we see new stuff that comes out. And everything
Speaker 1: that's created in the accelerator is immersed in a magnetic
Speaker 1: field that bends its path. So electrons fly out of
Speaker 1: the collision and they curve, and how much they curve
Speaker 1: depends on their charge. So one thing you can do
Speaker 1: pretty easily is look for particles that bend weirdly in
Speaker 1: your magnetic field because they have a tiny electric charge,
Speaker 1: they'll bend a tiny little bit. If they have some
Speaker 1: huge electric charge, they'll bend a lot. And so that's
Speaker 1: one quick thing that you can do is just like
Speaker 1: look for weirdly bending particles created in accelerators. But I
Speaker 1: guess the hard thing is, like we mentioned earlier, is
Speaker 1: that the universe is quantum, right, Like, if something has
Speaker 1: point o one electric charge, that doesn't mean it's going
Speaker 1: to interact with something that has one electric charge, right
Speaker 1: Like the universe only likes to make exchange. It if
Speaker 1: you have exact change, that's right, But some of those
Speaker 1: interactions are still allowed. Like if you have a particle
Speaker 1: flying by with zero point zero one electric charge, it
Speaker 1: can radiate a photon that doesn't violate conservation of charge,
Speaker 1: and then that photon can knock off an electron in
Speaker 1: your material can it can it generate a photon, but
Speaker 1: they aren't photons also quantized. Photons are quantized, but they're
Speaker 1: not electrically charged. So an electron can generate a photon
Speaker 1: or this para electron could also generate a photon, wouldn't
Speaker 1: break any of the rules. Yes, you have to quantize them.
Speaker 1: You have to generate one electron or two electrons. But
Speaker 1: having a tiny electric charge doesn't prevent you from generating
Speaker 1: an integer number of photons. But they would have to
Speaker 1: be really tiny photons, right like point or one of
Speaker 1: a photon. Kind of Now, you would still generate one photon,
Speaker 1: you just have a smaller probability of generating photons. So
Speaker 1: particles with smaller electric charge generate basically fewer photons, so
Speaker 1: they ionize material less. This is actually another way people
Speaker 1: are looking for these things. It might be that we
Speaker 1: are generating these millicharged particles in our accelerators, but we're
Speaker 1: not seeing them because they just don't leave a trace
Speaker 1: in our detectors, which mostly require particles to ionize the
Speaker 1: material to knock things out of the way as they
Speaker 1: fly through with their electric charge. So some folks have
Speaker 1: set up dedicated experiments far away from the collider, like
Speaker 1: near the collider, but through like meters and meters of rock.
Speaker 1: They stead of special detectors, hoping that a millicharged particle
Speaker 1: will fly all the way through that rock, not ionize
Speaker 1: anything because of it's low electric charge, and then suddenly
Speaker 1: decay in their detector, and nothing else basically could survive
Speaker 1: all of that rock. So if they see something there,
Speaker 1: they'll be pretty convinced they see something that can survive
Speaker 1: all that rock and also decay into photons, and so
Speaker 1: probably a particle with very low electric charge. I feel
Speaker 1: like this gets a little bit into the idea that
Speaker 1: maybe charge is really or of a probability which we
Speaker 1: probably can't deep too deep into, but maybe talk to
Speaker 1: us a little about the other ways that we're looking
Speaker 1: for these particles. Another way to look for these things
Speaker 1: is in cosmic rays. A lot of discoveries have been
Speaker 1: made just by looking at the particles that come from
Speaker 1: space because they smash into our atmosphere and are basically
Speaker 1: like little particle collisions that can produce all sorts of
Speaker 1: crazy stuff and so muans, for example, we're discovered by
Speaker 1: looking at particles coming from the upper atmosphere. And if
Speaker 1: you use a cloud chamber, this is just a chamber
Speaker 1: where the air is super saturated with water, so charge
Speaker 1: particles flying through it will tend to create droplets, so
Speaker 1: you can see the path of particles. You might have
Speaker 1: seen one in a museum sometime. You can see muons
Speaker 1: flying through it. Well, the drop density, like how many
Speaker 1: drops you make per centimeter, for example, depends on the
Speaker 1: charge because it depends on how often you're shooting out photons.
Speaker 1: And so if you saw a particle flying through there
Speaker 1: with very low drop density, that would tell you that
Speaker 1: you have a particle with low electric charge. So people
Speaker 1: are using cloud chambers to study cosmic rays and see
Speaker 1: if they can spot some of these very low electrically
Speaker 1: charged particles cool and how else are we looking for these?
Speaker 1: There's really fun experiments that are basically the successors of
Speaker 1: Milican's oil job experiment. They're taking a blob of matter
Speaker 1: and they're looking to see if there's basically the kind
Speaker 1: of atom that you were talking about earlier somewhere inside
Speaker 1: this blob of matter. Like imagine some other particle with
Speaker 1: a tiny charge orbiting a proton right bound to the nucleus,
Speaker 1: making some new kind of atom. And if it's also
Speaker 1: very massive, if this low charged particle has a high mass,
Speaker 1: it would be like bound to the nucleus and very
Speaker 1: very close to the nucleus. So people are looking for
Speaker 1: this like weird kind of stuff embedded in matter, and
Speaker 1: they theorize that it might have been formed early in
Speaker 1: the universe. But because these things would be very heavy,
Speaker 1: they were on Earth, they might have sunk down through
Speaker 1: the Earth's crust and all have pooled up near the
Speaker 1: center of the Earth. So you can't just like scoop
Speaker 1: up a chunk of dirt and look for these weird
Speaker 1: objects inside of them because they probably aren't any So
Speaker 1: what they're doing is they're looking for asteroids. They take
Speaker 1: like a slice of an asteroid and they see if
Speaker 1: they can find these weirdly charged heavy objects inside an
Speaker 1: asteroid slice. And they use an experiment similar to Milligans.
Speaker 1: It's called a leavetometer, where they have like a blob
Speaker 1: of the stuff magnetically suspended in this oscillating an eclectric field,
Speaker 1: and they watch the motion of it to see if
Speaker 1: they can detect something which can't be explained by an
Speaker 1: integer number of charges, very similar to the oil job experiment.
Speaker 1: Like maybe there is this kind of new kind of
Speaker 1: material here on Earth. Is that what you're saying with
Speaker 1: the new forest and the new particles, is that what
Speaker 1: you're looking for, You're looking for like regular asteroid rocks
Speaker 1: that somehow have this new kind of matter somehow stuck
Speaker 1: to it. Yeah, exactly, maybe deep within it there's one
Speaker 1: of these things. And they can try to figure out
Speaker 1: if a huge blob of matter has one or maybe
Speaker 1: two of these things by oscillating in an electric field
Speaker 1: and seeing it behaves strangely. It's a lot of details
Speaker 1: there we don't have time to get into, but the
Speaker 1: basic version is that you can take a chunk of
Speaker 1: matter and study its behavior in electric fields to see
Speaker 1: if it has any of these new weird atoms in
Speaker 1: it that might have milli charged particles within them. So
Speaker 1: you're you're basically looking for a new kind of matter, right, yeah,
Speaker 1: exactly that we had never seen before. And you're wondering,
Speaker 1: I wonder if it's in this rock or this rock,
Speaker 1: or how about that rock? Is it in this rock? No?
Speaker 1: How about there? Yeah that's exactly right, And that seems crazy,
Speaker 1: but you know, it could be that it's everywhere, that
Speaker 1: it's in all the rocks, and so might as well check.
Speaker 1: And so what they can do is they can say, look, oh,
Speaker 1: well we didn't find it, and so maybe it's just rare,
Speaker 1: and that they can do bigger and bigger experiments and
Speaker 1: check more and more rocks. You know, but imagine the
Speaker 1: universe where they're in every rock and nobody bothered to check. Right,
Speaker 1: What a crazy discovery that would be. All right, well,
Speaker 1: good luck finding this magical kind of matter in every
Speaker 1: rock out there in the universe. I guess we give
Speaker 1: us a sense of you know, why we're looking for
Speaker 1: this stuff. I mean, it sounds kind of impossible because
Speaker 1: we haven't seen it doesn't need to affect the rest
Speaker 1: of the universe in any strong way, otherwise we would
Speaker 1: have discovered this new kind of matter. Are we just
Speaker 1: trying to check the box that it doesn't exist. We're
Speaker 1: trying to check the box that it doesn't exist, but
Speaker 1: also we're trying to get a little bit of an
Speaker 1: answer to the question like why is there charge? And
Speaker 1: why does it have these properties? Why does it all
Speaker 1: seem to come in these rational fractions of each other.
Speaker 1: It's just not something that we understand, and so if
Speaker 1: we could find this thing, it would be a huge clue.
Speaker 1: Tell us, Oh, that's not a rule in the universe.
Speaker 1: It's not required to have that. That's just the examples
Speaker 1: you happen to discover early on. You know, there's lots
Speaker 1: of times in the universe when we drew big conclusions
Speaker 1: based on incomplete information. All of Newtonian physics, for example,
Speaker 1: is based on not ever seeing things go really fast
Speaker 1: or not ever seeing space get bent really really hard.
Speaker 1: So we want to be careful not to jump to
Speaker 1: conclusions based on the small amount of information we have.
Speaker 1: We want to check and see if it's possible well
Speaker 1: to do other things, and that'll tell us like, oh,
Speaker 1: this is a rule in the universe, or Nope, that's
Speaker 1: not a rule in the universe. Don't worry about it.
Speaker 1: I feel that this idea wouldn't really help you, right,
Speaker 1: Like if there is a new kind of matter with
Speaker 1: its own force and its own particle and field and everything,
Speaker 1: and that only sort of tinggently interacts with our that
Speaker 1: only looks like it has a small electric charge, that
Speaker 1: still wouldn't help you understand why electrical charges are the
Speaker 1: way they are, right, It would just open up a
Speaker 1: new question, like why does it only interact a little
Speaker 1: bit with this new magical field. But if that other
Speaker 1: field exists and it does interact with the photon, that
Speaker 1: means it has some connection to charge itself, and so
Speaker 1: it would shed some light on the nature of charge.
Speaker 1: But yeah, absolutely would opened up a whole bunch of
Speaker 1: other questions. All right, well, stay tuned, and in the meantime,
Speaker 1: I guess keep driving those electric cards because it's putting
Speaker 1: those electrons to work. And don't overcharge your credit card.
Speaker 1: All right. We hope you enjoyed that. Thanks for joining us,
Speaker 1: see you next time. Thanks for listening, and remember that
Speaker 1: Daniel and Jorge Explain the Universe is a production of iHeartRadio.
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