Speaker 1: Hey, Orgey, I have a question for you about forces.
Speaker 1: For me, you're asking the cartoonists about forces. Yeah, but
Speaker 1: it's not a physics question. It's a Star Wars question.
Speaker 2: Oh then yeah, I have a master's degree in Star Wars.
Speaker 2: It's like a jd but it's more like a Jedi.
Speaker 1: Nice. So there's like a dark side and the light
Speaker 1: side to the force, right, uhh, So are these really
Speaker 1: two separate forces, like unified by a physicist into a
Speaker 1: single force?
Speaker 2: Kinda? They're like two sides of the same force. That's
Speaker 2: how they call it. That's why it's called the dark
Speaker 2: side and the light side as a force venue.
Speaker 1: So they're sort of like doing physics in the Star
Speaker 1: Wars universe.
Speaker 2: I think it's more of a fantasy, although you just
Speaker 2: made me think, like, could there be physicists in the
Speaker 2: Star Wars universe? I mean, somebody had to design those spaceships.
Speaker 1: Maybe it's just engineers.
Speaker 2: Maybe the Jedi are engineers force engineers that would explain everything.
Speaker 2: You can be a Jedi. E. Hi, I'm Horamy Cartooniz.
Speaker 2: I'm the author of Oliver's Great Big Universe.
Speaker 1: Hi. I'm Daniel. I'm a particle physicist and a professor
Speaker 1: at UC Irvine, and I'm still forcing myself to try
Speaker 1: to understand physics.
Speaker 2: Yet the force yourself I said, you were doing it
Speaker 2: out of pure joy and curiosity.
Speaker 1: I am, But sometimes you got to force those ideas
Speaker 1: into your head. It's like reformatting your brain.
Speaker 2: Disc because it don't fit or because there are too
Speaker 2: complex what's going on.
Speaker 1: Because they're not always intuitive. You know, the way that
Speaker 1: we see the universe and experience it isn't always the
Speaker 1: way it makes most sense to describe it mathematically. So
Speaker 1: sometimes it takes a little bit of a brain reformat
Speaker 1: to make it all work in your mind.
Speaker 2: But if you have to force it doesn't mean you're
Speaker 2: donate the wrong way. Shouldn't it all flow.
Speaker 1: Dude, I'm not sure intuition and like sitting around the
Speaker 1: night staring up at the stars, is enough to figure
Speaker 1: out how the universe works. It needs some sort of
Speaker 1: method because sometimes the answers are really counterintuitive.
Speaker 2: Well, it worked for a long time, didn't it, using
Speaker 2: our intuition staring up the nice guy to work for
Speaker 2: thousands of years until maybe recently.
Speaker 1: Depending on your definition of worked. I mean it also
Speaker 1: led us to big misunderstandings in how the universe worked,
Speaker 1: thinking that the Earth was at the center of everything,
Speaker 1: for example, not really understanding all of the effects around us.
Speaker 2: Well, it's led us somewhere, and we're hoping that it's correct.
Speaker 2: Isn't that right?
Speaker 1: It's led us today here to this podcast, the culmination
Speaker 1: of all human wondering.
Speaker 2: That's where we are, the climax of science. We are
Speaker 2: the end result of all human curiosity, knowledge and inquiry
Speaker 2: right here, right now. This is what it's come down to. Now,
Speaker 2: Daniel say something profound.
Speaker 1: We are a flea on the shoulders of giant.
Speaker 2: I think somebody said that already.
Speaker 1: I'm a flea standing on the shoulder of the person
Speaker 1: who said that already.
Speaker 2: We're just fleas on the universe of podcasts.
Speaker 1: I think exactly. I hope nobody scratches this off.
Speaker 2: That's right, sucking up the blood of advertising money. But anyway,
Speaker 2: speaking of this podcast, Welcome to our podcast, Daniel and
Speaker 2: Jorge Explain the Universe, a production of iHeartRadio.
Speaker 1: In which we guide you on the journey of humanity
Speaker 1: from being totally bewildered and confused about the universe we
Speaker 1: find ourselves in to slowly piecing together a picture that
Speaker 1: makes sense, combining ideas and merging concepts into a unified
Speaker 1: understanding of how the whole universe works. What are these
Speaker 1: laws that underlie everything? How do they come together to
Speaker 1: make the universe that we love and experience?
Speaker 2: That's right. It is a lovely universe full of questions
Speaker 2: and mysteries. And we are the fleas that are making
Speaker 2: you scratch that itch of curiosity about how it all works,
Speaker 2: what's going on? And what are the forces or force
Speaker 2: behind the motion of the stars.
Speaker 1: Wow, we're the Flea's huh. That's not very glamorous.
Speaker 2: Flea's good, isn't it. He's a basis for Red Hot
Speaker 2: Chili Peppers, so you can be a cool flea.
Speaker 1: I have no idea what you're talking about. Isn't the
Speaker 1: flea also a superhero? You're thinking about the Tick?
Speaker 2: I think you're thinking of the Tick? Yes, wrong, Although
Speaker 2: faith there should be a superhero called the Flea.
Speaker 1: Is the Flea the name of a musician in Red
Speaker 1: Hot Chili Peppers?
Speaker 2: No, he's uh. He's got control of the Flea Force,
Speaker 2: both the dark side and the lights side of the
Speaker 2: Flea Force.
Speaker 1: What are you talking about? I am totally lost.
Speaker 2: I think we lost our way here a little bit.
Speaker 2: So let's scratch our way back and say that the
Speaker 2: podcast is it's about all questions out there, even the
Speaker 2: ones that have to do with superheroes and not superheroes.
Speaker 1: And as curious humans in the universe, we look around
Speaker 1: and we see all sorts of stuff happening. We see lightning,
Speaker 1: we see magnets, we see rain, we see stars. We
Speaker 1: want to understand each and everything. What is the story
Speaker 1: behind it, what is the mechanism, what is the mic
Speaker 1: groscopic explanation for what's really happening. But we don't want
Speaker 1: a bunch of individual stories. Here's the law for like being,
Speaker 1: and here's the law for magnets, and here's the law
Speaker 1: for rain. We want one understanding. We want to unify
Speaker 1: everything down into a single law that explains the whole universe,
Speaker 1: because we think the universe does follow a law.
Speaker 2: That's right. It's been one of the most amazing discoveries
Speaker 2: of humankind and of science to see that behind the
Speaker 2: chaos of motion around us, there are apparently fundamental laws
Speaker 2: which govern everything. And those laws can sort of be
Speaker 2: boiled down to a simple set of equations that describe
Speaker 2: only a few forces in the universe.
Speaker 1: And we can make progress in understanding these things by
Speaker 1: doing more experiments. But we can also make progress just
Speaker 1: by looking at the mathematical structure of these forces and say, hmm,
Speaker 1: what's the relationship between them? Why do so many of
Speaker 1: them have the same sort of force equation that's like
Speaker 1: one over are squared. Why is this one different from
Speaker 1: that one? We can look for patterns between them the
Speaker 1: same way that we've used them to explain the things
Speaker 1: we see in the universe, sort of like a mathematical
Speaker 1: exploration of how the universe works.
Speaker 2: Yeah, and I guess that's sort of been the history
Speaker 2: of science in general, right, Daniel, in the sense that,
Speaker 2: you know, the world is pretty complex when we see
Speaker 2: it around us, but little by little science has sort
Speaker 2: of found the commonalities, found, the patterns, found, the underlying
Speaker 2: laws that seem to govern different phenomena, and it all
Speaker 2: sort of turns out to be due to a simpler
Speaker 2: and ever simplifying set of equations and concepts.
Speaker 1: Yeah, that's been the trend, and it's sort of incredible.
Speaker 1: I mean, philosophically, you have no guarantee number one that
Speaker 1: the universe does make sense, but number two that we
Speaker 1: could figure it out, you know, that it's within like
Speaker 1: the realm of human intelligence to solve this puzzle. And
Speaker 1: number three that there even is a single unifying law
Speaker 1: that describes the universe. You might have had a scenario
Speaker 1: where like, different things are run by different laws that
Speaker 1: just don't overlap or draw dotted lines between them. But
Speaker 1: so far the trend seems to be towards unification, towards simplification,
Speaker 1: towards a single underlying law, one we haven't yet been
Speaker 1: able to uncover.
Speaker 2: Right, I guess it could have been that, you know,
Speaker 2: the universe worked in such a complicated way that it
Speaker 2: would have been the equivalent of like us being fleas
Speaker 2: or having the brain of a flea and trying to
Speaker 2: understand what we know now of the universe. Right Like,
Speaker 2: it could have been the universe was too complicated for
Speaker 2: our brains to even try to understand or figure out
Speaker 2: how it works.
Speaker 1: It could still be right, because we certainly have not
Speaker 1: figured out the whole universe. We don't know if that's
Speaker 1: just because we haven't had enough time, or smart enough
Speaker 1: human hasn't come along, or if the universe is just
Speaker 1: beyond our ken it might be that, like the kind
Speaker 1: of mathematics we use to think about the universe is
Speaker 1: not appropriate, and that we're not capable of the sort
Speaker 1: of higher level math that describes reality.
Speaker 2: When you're saying we could still be fleas, we.
Speaker 1: Could still general analogy exactly. It might be, for example,
Speaker 1: that it requires higher intelligence or more brain power, or
Speaker 1: a different kind of mathematical explanation, you know, one that
Speaker 1: doesn't favor simplification in terms of little mathematical stories, but
Speaker 1: more like tabulation. It might be that our ais are
Speaker 1: more capable of sort of grocking the way the universe
Speaker 1: works than we are. And then you have fun philosophical
Speaker 1: questions like, well, if you build an AI that understands
Speaker 1: the universe, do you also understand it right?
Speaker 2: Or it could be that maybe fleas can understand the
Speaker 2: universe what we do. Is that possible, like for them
Speaker 2: to have maybe some quirk in the brain that makes
Speaker 2: them capable of understanding the universe but not us.
Speaker 1: It's certainly possible. I think it's very unlikely with fleas
Speaker 1: because their brains are so simple.
Speaker 2: But takes. You're saying ticks can do it.
Speaker 1: There are other things on Earth that are definitely intelligent
Speaker 1: in different ways from humans. I mean, crows can count.
Speaker 1: Octopi have really interesting intelligences. You know. We think that
Speaker 1: their neural computation is mostly happening in their legs, so
Speaker 1: like their consciousness is a little bit more distributed. That
Speaker 1: might lead them to a different way of thinking mathematically
Speaker 1: and maybe an easier way to understand the universe. We
Speaker 1: just don't know what the deepest nature of the universe
Speaker 1: is and what kind of brain is best to explore.
Speaker 2: So just ask an octopus maybe to explain physics to you.
Speaker 1: You might get eight answers, though.
Speaker 2: Yeah, it might get wrapped up in all the tentacles
Speaker 2: of the answer. But yeah, it's been a journey for
Speaker 2: humans to boil everything down into a single sort of
Speaker 2: set of equations. Now, how far can we go? That
Speaker 2: is maybe the question we're asking today. So today on
Speaker 2: the podcast, we'll be tackling the question did all the
Speaker 2: forces used to be one? One?
Speaker 3: What?
Speaker 2: Daniel? One force, one band, one rock band, one octopus.
Speaker 1: I'm going with the flea theory of the universe. One
Speaker 1: flea explain every one flea?
Speaker 2: Huh? But then what was the flea on?
Speaker 1: What is the shoulder? Of the universe. No, it's boiling
Speaker 1: it all down to one force, is the question?
Speaker 2: So like all the forces used to be one, meaning
Speaker 2: first of all, that the forces can change like a
Speaker 2: force can change.
Speaker 1: Yeah, we think the forces operate differently at different sort
Speaker 1: of temperatures, and the universe is definitely cooling. So as
Speaker 1: the universe cools and expands, it goes through different phases,
Speaker 1: and so the forces look different as we move through
Speaker 1: those different phases of the universe.
Speaker 2: So we have some forces that we think govern the
Speaker 2: universe and how things move in it. And so the
Speaker 2: question here is was there a time in the universe
Speaker 2: when they were basically the same thing or when they
Speaker 2: were sort of acting the same way exactly?
Speaker 1: And can we recreate that scenario in our particle colliders.
Speaker 2: Well, as usual, we're wondering how many people had heard
Speaker 2: of this question, this idea and do they think that
Speaker 2: all the forces could have been one before?
Speaker 1: Thanks very much to everyone who plays in this audience
Speaker 1: participation segment. We love hearing your voices and if you're
Speaker 1: out there and would like to hear your voice on
Speaker 1: the podcast, don't be right to me. Two questions at Danielandjorge.
Speaker 2: Dot com So think about it for a second. Do
Speaker 2: you think all the forces used to be one? Here's
Speaker 2: what people had to say.
Speaker 3: I think we have a pretty good idea that strong, weak,
Speaker 3: and electromagnetism all used to be one force back in
Speaker 3: the first gazillionth of a second of existence. Gravity, we
Speaker 3: don't know. We may not even be a force like
Speaker 3: the others. That's still an open question.
Speaker 2: My simple answer would be yes.
Speaker 4: Whether you believe in creation or you believe in some
Speaker 4: other form evolution, everyone believes that there was one moment,
Speaker 4: one singularity, one moment, one thing that set everything in motion.
Speaker 4: So yes, all of the forces used to be one.
Speaker 5: I wonder if the four forces that there are, electromagnetism,
Speaker 5: weight force, and strong force all seemed to be very similar.
Speaker 5: But there's something different about gravity, I think. So, I
Speaker 5: think that the first story you potentially used to be one,
Speaker 5: but gravity, there's something different about that.
Speaker 6: Of course, the force, the one that unifies, give together
Speaker 6: all the universe, and the only master Jediyes able to control.
Speaker 6: That's for sure the original force for all the other forces.
Speaker 3: Well, not.
Speaker 7: In seriousness, I suspect that that is what physicists had
Speaker 7: been trying to do for a long time to unify
Speaker 7: the forces. And although the idea of all the forces
Speaker 7: coming from one sounds very evolutionary and very tempting, I
Speaker 7: think a lot of smart people have not been able
Speaker 7: to figure it out how to solve that.
Speaker 6: So I'm not sure at this point.
Speaker 8: I feel like all the forces would have necessarily had
Speaker 8: to have been one at the origination point, But what
Speaker 8: happened after that or how long they stayed one before
Speaker 8: becoming separate and distinct?
Speaker 2: I have no idea, all right, A wide range of answers,
Speaker 2: from religion to star Wars, which is a religion to
Speaker 2: some people, to.
Speaker 1: Faith in physics to figure it all out.
Speaker 2: Or faith not the Jedi, the physics Jedi doctor Yoda
Speaker 2: and his theories of the universe. All right, Well, a
Speaker 2: wide range of answers. Some people think that maybe yes,
Speaker 2: or maybe not one, or maybe we'll never.
Speaker 1: Know all reasonable answers.
Speaker 2: All right, Well, let's dig into Daniel. What are the forces?
Speaker 1: So first, just to put it in context, remember that
Speaker 1: physics doesn't just deal with forces. We also deal with
Speaker 1: stuff like we see stuff out there in the universe, particles, whatever.
Speaker 1: But those particles are being acted on by forces, and
Speaker 1: so we want to when we want to simplify the universe,
Speaker 1: really the end goal would be to explain what is
Speaker 1: the most basic stuff in the universe can be explained
Speaker 1: in terms of like one kind of stuff and can
Speaker 1: be explained all the motion the interactions of those things
Speaker 1: in terms of one force. So this is sort of
Speaker 1: like half of the larger physics school to unify everything
Speaker 1: down to like one kind of particle and one kind
Speaker 1: of force.
Speaker 2: And so far we boil it down to a handful
Speaker 2: of forces.
Speaker 1: Right, that's right, So we have three or four or
Speaker 1: five forces, depending on how you count those forces are,
Speaker 1: like electricity.
Speaker 2: What do you count within tentacles?
Speaker 1: Well, then you're counting in base eight, so you're still
Speaker 1: going to get the same number.
Speaker 2: It just kind of seems like you're guessing, you're sounding
Speaker 2: very undefinitive. You're like three or four or five or
Speaker 2: maybe six or seven, perhaps kind of maybe eight.
Speaker 1: It depends on how this is presented to people, And
Speaker 1: I've learned that a lot of people have had this
Speaker 1: presented in elementary school or in high school sort of
Speaker 1: very different ways. And so if you ask people like
Speaker 1: how many forces are there? Sometimes you hear three. Sometimes
Speaker 1: you hear five, and so I just wanted to be inclusive.
Speaker 1: Will clarify it. So if you think most broad we
Speaker 1: have sort of five forces. There's one electricity, two magnetism,
Speaker 1: three the weak nuclear force for the strong nuclear force,
Speaker 1: and then the fifth sort of question MARKI one is gravity.
Speaker 1: So in the sort of broadest sense you have five.
Speaker 2: I see, I like that designation question marking. Like we'll
Speaker 2: just call it maybe the biggest most significant constant in
Speaker 2: the universe. That then space and time we'll just call
Speaker 2: it question marking.
Speaker 1: Well, we have a lot of question marks about gravity,
Speaker 1: you know, like is it even a force? How does
Speaker 1: it all work? Can it be described quantum mechanically?
Speaker 2: Dot dot dot dot dot YadA, YadA, yah.
Speaker 1: YadA, YadA YadA. So particle physicists tend't sort of put
Speaker 1: that one aside, be like, you know what, let's worry
Speaker 1: about gravity another day and just think about the other
Speaker 1: four the things that we know are actually forces, because
Speaker 1: you know, gravity we don't even think it is a force.
Speaker 1: It doesn't cause acceleration, It just bend space time. So
Speaker 1: the other four are things we definitely think are forces,
Speaker 1: and those are the ones we're working hard to unify
Speaker 1: into one idea.
Speaker 2: Does this Traditionally, there are four other forces besides gravity.
Speaker 1: Right, yeah, exactly, So you.
Speaker 2: Just listed them, So should we go one by one? Yeah,
Speaker 2: what's electricity or what's the electric force? Yeah, so this
Speaker 2: is just the force between particles that have charge. Right,
Speaker 2: two electrons will push away from each other, or an
Speaker 2: electron and proton pull on each other because they have
Speaker 2: electric charge. You could also say that's sort of like
Speaker 2: what electric charge is. Electric charge is a label we
Speaker 2: put on particles that seem to feel this electric force.
Speaker 2: So some things have no charge, like the neutron or
Speaker 2: the neutrino. Some particles do.
Speaker 1: Have charge, like the electron, the positron, the proton, and
Speaker 1: these definitely feel a force. Like you can make an
Speaker 1: electric field and use it to accelerate particles through that field.
Speaker 1: We definitely see that happening.
Speaker 2: In the universe, and an electric field would have to
Speaker 2: be generated by other particles would charge in the right.
Speaker 1: Yeah, exactly. So one particle creates an electric field and
Speaker 1: that operates on other particles and pushes and pulls on them.
Speaker 2: And by pushing it pointly, you mean like if you
Speaker 2: just leave them there, they'll they'll start moving. Yeah, exactly exactly,
Speaker 2: they accelerate f equals MA forces require acceleration, and the
Speaker 2: m in there is a then inertial mass of that object.
Speaker 2: And so basically anytime we see acceleration, we're like, okay,
Speaker 2: there's a force there, what's causing it? And its Historically
Speaker 2: we see electricity in lots of places, static electricity, lightning
Speaker 2: right now, of course we generate electricity and all of
Speaker 2: those really very disparate phenomena, those different early human experiences
Speaker 2: can now be explained using a single theory of electricity
Speaker 2: and electric forces. Now, like, what's an example of everyday
Speaker 2: life where we see the electric force, Like when our
Speaker 2: hair stands up. If you rub a balloon and you
Speaker 2: put in your hair, that's the electric force acting on
Speaker 2: your hairs.
Speaker 1: Right, that's definitely the electric force acting on your hair. Exactly,
Speaker 1: you have like ionized particles on the balloon and on
Speaker 1: your hair and they're attracting each other.
Speaker 2: Okay, what's another example of the electric force.
Speaker 1: Batteries, Right, batteries create an electric potential to create current flow.
Speaker 1: Or if you stick your fingers in the socket not recommended,
Speaker 1: you'll definitely become acquainted with.
Speaker 2: The electric force, but you'll get a zap, but it's
Speaker 2: not necessarily going to push or pull youard.
Speaker 1: There's a lot of energy there that's pushing and pulling
Speaker 1: on those electrons to create the current, right, and so
Speaker 1: that energy will get deposited into your skin in a
Speaker 1: very unpleasant way. But yeah, I won't push or pull
Speaker 1: push a whole bunch of electrons onto you, yeah, or
Speaker 1: through you. Now, what about like the atom, like the
Speaker 1: electrons hanging out near the nucleus which has positive protons,
Speaker 1: is that the electric force keeping the electron orbiting around
Speaker 1: the atom. Yeah, that's exactly it. There's a force between
Speaker 1: the electron and the proton and that's what's attracted them together.
Speaker 1: You know, in the early universe, electrons were moving really
Speaker 1: really fast, and then when they slowed down, the proton
Speaker 1: had enough electric force to pull on that electron and
Speaker 1: to bind it into an atom. So that's definitely because
Speaker 1: of the force between them. The same with it, Like
Speaker 1: the Earth is bound into the Sun's orbit by the
Speaker 1: force of graph gravity. Turned off, the Earth would just
Speaker 1: fly off into space. If you turned off electricity, electrons
Speaker 1: would fly off into space and leave their protons behind.
Speaker 2: Right, or at least in a question mark you kind
Speaker 2: of way. I guess, now, how is the electric force
Speaker 2: different than the magnetic force or force of magnetism, because
Speaker 2: I always kind of feel the same thing.
Speaker 1: Maybe, well, they're definitely very closely connected. And we'll get
Speaker 1: into that when we talk about the unification of the forces,
Speaker 1: because that was the first big success of that whole
Speaker 1: program of trying to explain multiple forces in terms of
Speaker 1: one idea. But historically, like a long time ago, in
Speaker 1: terms of like basic human experience, magnetism and electricity seem different.
Speaker 1: You know, there are magnets out there in the world
Speaker 1: and you don't get a spark when you touch them.
Speaker 1: You don't have to have charge to have magnetism. So
Speaker 1: like kitchen magnets, right, or like maglev trains, these are
Speaker 1: all examples of magnetism out there in the world.
Speaker 2: But they aren't they sort of maybe the same as
Speaker 2: the electric force, like I always thought, maybe like a
Speaker 2: magnet repels or is attracted to my fridge somehow because
Speaker 2: the negative electrons and my magnet are somehow attracted to
Speaker 2: the positive spots in the fridge. Or are you just
Speaker 2: talking about like what we thought before?
Speaker 1: Now, of course, We definitely know that electricity and magnetism
Speaker 1: are very closely related. So closely related some people are
Speaker 1: taught that they're the same thing, and you clearly have
Speaker 1: an understanding of them as two sides of the same coin.
Speaker 1: But yet historically they were different. And it wasn't until
Speaker 1: James Maxwell noticed that the mathematics of electricity and the
Speaker 1: mathematics of magnetism, like you wrote down the equations of
Speaker 1: the two, they were very very similar, and there's this
Speaker 1: like beautiful symmetry between them, and that they were interconnected.
Speaker 1: That things with electric charges can make magnetic fields, magnetic
Speaker 1: fields can generate electric fields. The two things definitely seem linked.
Speaker 1: So in your fridge magnet, where does that magnetism come from, Well,
Speaker 1: it's nothing in the universe we know of that like
Speaker 1: just generates magnetic fields the way that an electron generates
Speaker 1: electric fields. All the magnetic fields in the universe come
Speaker 1: from the motion of electric charges. For example, atoms have
Speaker 1: spin and electrons have spin, and these things have charge,
Speaker 1: and so that generates a magnetic field because moving charges
Speaker 1: generates a magnetic field. So all the little atoms in
Speaker 1: that fridge magnet all lined up with their quantum spin
Speaker 1: generating little tiny magnets with north and south poles. So
Speaker 1: it comes from the charges. In the end, there's a
Speaker 1: very deep connection between electricity and magnetism.
Speaker 2: Yes, And would you say maybe the difference is that
Speaker 2: electricity or the electric force is of course between charges
Speaker 2: that are plus or minus, but the magnetism force is
Speaker 2: maybe the force between like moving electrons. Like if you
Speaker 2: have a moving electron over here moving in a circle,
Speaker 2: it's gonna somehow influence other electrons around it to also
Speaker 2: move in a circle. But yet they have to be
Speaker 2: moving to do that.
Speaker 1: Yeah, and I think you've put your finger on one
Speaker 1: of the biggest differences between electricity and magnetism. Mathematically they're
Speaker 1: structured very similarly. But there are sources of electric charge
Speaker 1: in the universe electrons, for example, smilar source of magnetic
Speaker 1: charge in the universe. If they did exist, they would
Speaker 1: be called magnetic monopoles, be like a particle with a magnetic
Speaker 1: north or a magnetic south. But we've never seen those things.
Speaker 1: We've only ever seen electrically charged things like electrons generating
Speaker 1: little dipoles like magnet with a north and a south.
Speaker 1: So I think basically what you're saying is that all
Speaker 1: magnetism in the universe is actually generated by things with
Speaker 1: electric charge. And that's totally correct as far as we.
Speaker 2: Know, so like before we thought it was something else,
Speaker 2: but really it's just maybe another part or another aspect
Speaker 2: of the electric force.
Speaker 1: Yeah, Or there are two sides of the same coin, right,
Speaker 1: Electricity and magnetism are really one thing. You could say
Speaker 1: it's all electric whatever. You can call it electromagnetism to
Speaker 1: reflect that there's two sides of it. But yeah, mathematically
Speaker 1: it makes much more sense to think about it as
Speaker 1: one thing because electric fields cause magnetic fields, magnetic fields
Speaker 1: cause electric fields, and even light is like an oscillation
Speaker 1: between electra and magnetic field back and forth. So it
Speaker 1: makes much more sense you click them together.
Speaker 2: It's like magnets.
Speaker 1: Yeah, it's like treating the front of an elephant in
Speaker 1: the back of the elephant is totally separate things, Like
Speaker 1: obviously they're connected, right, It makes much more sense to
Speaker 1: just think about the elephant and not just the two
Speaker 1: separate pieces.
Speaker 2: Unless it's like a weird Siamese elephant.
Speaker 1: Does that happen for other species?
Speaker 2: I don't know, I think so maybe aren't there like
Speaker 2: two headed snakes.
Speaker 1: I'm gonna google two headed elephant when we're done here.
Speaker 2: Okay, but why wait? So we've talked about some of
Speaker 2: the basic forces around those electricity, magnetism, and now let's
Speaker 2: dig into the nuclear forces that govern how things move
Speaker 2: in at the particle level inside of the atom, and
Speaker 2: then we'll see if maybe they're all just the same
Speaker 2: force underneath it all. So we're gonna explore that be first,
Speaker 2: let's take a quick break, all right, we're forcing our
Speaker 2: way into a discussion of the forces and whether or
Speaker 2: not they can all be described as one force, either
Speaker 2: now or maybe in the past history of the universe.
Speaker 2: Do they have the same origin? All the forces that
Speaker 2: we know about, And so we talked about the electric
Speaker 2: force and the magnetism force, which turned out to be
Speaker 2: the same force kind of right, You sort of see
Speaker 2: it now as the same force.
Speaker 1: We definitely see it as one concept. We originally discover
Speaker 1: them sorta separately and then realized that it made much
Speaker 1: more sense if you click them together into one idea.
Speaker 2: Well, you keep saying it's a concept or an idea,
Speaker 2: Is it a force or not?
Speaker 1: Yeah, it's a force for sure. Electromagnetism is a force. Absolutely,
Speaker 1: it causes things to accelerate, and you can think about
Speaker 1: it either in terms of the electromagnetic field or if
Speaker 1: you like the particle picture, you can think about as
Speaker 1: exchanging virtual photons back and forth to carry that momentum.
Speaker 2: Okay, so that's one force electromagnets. Okay. So then how
Speaker 2: did they realize that the electric force and the magnetic
Speaker 2: force were the same thing or part of the same force.
Speaker 1: This is really an example of like the triumph of
Speaker 1: theoretical physics, because it wasn't an experiment. It wasn't like
Speaker 1: somebody went out and did a bunch of experiments and
Speaker 1: then had an Aha moment when they proved that electricity
Speaker 1: and magnetism were the same thing. It was just a
Speaker 1: guy sitting in his study like writing out equations and
Speaker 1: noticing patterns. So this is the Scotsman. Maxwell figured out
Speaker 1: a way to write down a bunch of different laws
Speaker 1: like Ampier's law and Gauss's law and Kulamb's law and
Speaker 1: all this stuff describing different parts of electricity and magnetism.
Speaker 1: He figured out a way to write it all in
Speaker 1: very similar way, and he noticed, like, oh my gosh,
Speaker 1: we're talking about this thing called the electric field and
Speaker 1: talking about that thing called the magnetic field. But the
Speaker 1: math is so similar that basically the same equations for
Speaker 1: both things. And that's what led him to the discovery
Speaker 1: that there really are two parts of something larger, but.
Speaker 2: They weren't exactly the same. Right. They didn't describe like
Speaker 2: the like the magnetic the you know, the force. The
Speaker 2: equations for magnetism didn't describe how electric charges move. So
Speaker 2: what do you mean they were similar? Like you could
Speaker 2: get one from the other, or you could have them
Speaker 2: all on the same equations, then they would be okay
Speaker 2: with each other.
Speaker 1: What do you mean, Well, the law for like how
Speaker 1: you generate a magnetic field and the law for how
Speaker 1: you generate an electric field. You write them down mathematically,
Speaker 1: they look the same. You just like replace electric field
Speaker 1: with magnetic field, and now you have the other law.
Speaker 1: It's like finding replace E for B. But they work
Speaker 1: the same. But that doesn't mean they're the same. If
Speaker 1: you can write them down using the same mathematics, that's
Speaker 1: a strong hint that maybe they are closely related. And
Speaker 1: it's not just that they have the same mathematics, but
Speaker 1: they're very closely linked. Like the magnetic field appears in
Speaker 1: the laws for the electric field, because like, changing magnetic
Speaker 1: fields will cause an electric field, and changing electric fields
Speaker 1: cause a magnetic field. So not only is the mathematics
Speaker 1: for each one similar, but they appear in each other's equations.
Speaker 2: But then this appearing in each other's equations, didn't they
Speaker 2: have to figure that out experimentally?
Speaker 1: Yeah, and that's something we knew that, Like, for example,
Speaker 1: you could generate a magnetic field by changing electric fields, right,
Speaker 1: and that's something we already knew. But Maxwell actually noticed
Speaker 1: that there was like a flaw in this symmetry. He's like,
Speaker 1: you know, the equations we have are really beautiful and symmetric,
Speaker 1: and they match each other perfectly, except there's a missing piece.
Speaker 1: There's like a hole here, Like if the equations were
Speaker 1: a little bit different, they would be even more beautiful
Speaker 1: and symmetric. So he said, like, hmm, maybe we just
Speaker 1: missed something, and so he corrected one of the existing
Speaker 1: laws was ampire's circuit law, and added a term, the
Speaker 1: term that tells you get electric currents from changing magnetic fields.
Speaker 1: And he sort of like predicted that this thing was real,
Speaker 1: and then it went out there and did the experiment
Speaker 1: and found it so like the symmetry of the mathematics
Speaker 1: by itself led him to discover something physical.
Speaker 2: It kind of seems like he was looking at physical
Speaker 2: things that other experimental is found and then he kind
Speaker 2: of pieced it all together from his couch.
Speaker 1: Yeah, exactly. He was sitting in his study and had
Speaker 1: this like moment of insight. Been really incredible. And so
Speaker 1: really what this shows you is that they are part
Speaker 1: of this larger concept that it just makes much more
Speaker 1: sense to treat them together rather than trying to pull
Speaker 1: them apart. It's like taking the Earth and drawing a
Speaker 1: dotted line through half of it. Like, yeah, you could
Speaker 1: do that, you could talk about the northern hemisphere in
Speaker 1: the southern hemisphere, but it really makes more sense to
Speaker 1: talk about the whole Earth.
Speaker 2: And so what we thought were two forces were actually
Speaker 2: one force.
Speaker 1: Yeah, actually we're just one force. And this is really
Speaker 1: important work because not only did it help us unify
Speaker 1: it and like reduce our list of forces down by one,
Speaker 1: but it also was like the groundwork for relativity. You know,
Speaker 1: understanding that light was a wave in electromagnetic fields, and
Speaker 1: the questions about the velocity of that wave is what
Speaker 1: led to attempts to measure the velocity of light in
Speaker 1: different directions, and the whole puzzle of how light moves
Speaker 1: at the same speed for all observers and basically led
Speaker 1: to relativity. So if it hadn't been for Maxwell, we
Speaker 1: wouldn't have had Einstein's.
Speaker 2: Breakthroughs are you saying Eislein was the flee who stood
Speaker 2: on the shoulder of Maxwell.
Speaker 1: I think he was a giant standing on the shoulders
Speaker 1: of another giant.
Speaker 2: Let's just hold flee, the giant flee standing on the
Speaker 2: shoulders of another giant flee exactly.
Speaker 1: And there's one more really important lesson in this unification
Speaker 1: that we're going to see happen again and again, and
Speaker 1: we hope to see again in the future, and that's
Speaker 1: the unification of the strength of the forces. Like magnetism
Speaker 1: in general feels weaker than electricity, Like electricity just seems
Speaker 1: like a more powerful force. And if you look at
Speaker 1: like the force equation for like how an object is
Speaker 1: affected by electric fields and magnetic fields, they're a little
Speaker 1: bit different. The Lorentz force law that maybe people out
Speaker 1: there know if they're electrical engineers or whatever, it tells
Speaker 1: you that the force on electron depends on the strength
Speaker 1: of the electric field and the force from magnetism also
Speaker 1: depends on the velocity, Like as things move faster, the
Speaker 1: force from magnetism has a stronger effect.
Speaker 2: So what does that tell you about the forces?
Speaker 1: So what that tells you is that as you approach
Speaker 1: the speed of light, these two forces get the same strength.
Speaker 1: Like at very very low speeds, if your velocity is
Speaker 1: close to zero, magnetism has almost no effect, but electricity
Speaker 1: is still very strong. But as you approach the speed
Speaker 1: of light, magnetism grows in strength to be the equal
Speaker 1: of electricity. That's why light is so perfectly balanced between
Speaker 1: electricity and magnetism. The energy flows back and forth because
Speaker 1: the magnetic fields and the electric fields are the same
Speaker 1: strength at the speed of light. And that's the clue
Speaker 1: about the history of the universe, because as we look
Speaker 1: back in time in the universe, things get hotter and denser,
Speaker 1: higher velocity, electricity and magnetism basically become the same thing.
Speaker 1: So at the speed of light, I eat earlier in time,
Speaker 1: these things really were much more unified.
Speaker 2: Wait wait, I thought they were already unified. You're just saying,
Speaker 2: like back in the beginning of the universe, they were
Speaker 2: more balanced with each other. But now that things are cooler,
Speaker 2: like one of them is obviously is stronger than the other.
Speaker 1: Yeah, exactly. You can still unify them today and do
Speaker 1: the same mathematical framework, but they were more in balance
Speaker 1: back in the early universe.
Speaker 2: Everything was better before, back.
Speaker 1: In the good old days when electronics moved at the
Speaker 1: speed of light in.
Speaker 2: The Big Bang, didn't have all these kids with their tiktoks.
Speaker 1: But if you think about in terms of history, there's
Speaker 1: like a moment in the universe when basically everything is
Speaker 1: moving at the speed of light, very very early on,
Speaker 1: and back then electricity and magnetism had the same strength.
Speaker 1: But as the universe cools, magnetism gets weaker because it
Speaker 1: depends on velocity and electricity doesn't, and that's when the
Speaker 1: two split. That's the pattern we hope to see in
Speaker 1: the other forces that as we rewind the universe backwards,
Speaker 1: we go deeper into our history, higher speeds, hotter temperatures,
Speaker 1: denser material, maybe things get to have the same equal strength.
Speaker 2: Well, they have the same strength, but that doesn't mean
Speaker 2: they're more or less unified. Like you just said, like
Speaker 2: as things cool, they split, but did they really split
Speaker 2: it's more like they preserved its strength as the universe. Cool,
Speaker 2: but that doesn't mean that they're like it's only became different.
Speaker 2: It just sort of looked different to us. Yeah, it
Speaker 2: looks different, exactly. It's like cracks, like the symmetry is
Speaker 2: broken a little bit. They're not so indistinguishable, or they're
Speaker 2: more distinguishable.
Speaker 1: Yeah, they're more interesting thing exactly. And if the forces
Speaker 1: do have the same strength back in the early universe,
Speaker 1: that's a clue that may be.
Speaker 2: I mean they were the same back in the beginning
Speaker 2: of the universe. There is still different or two sides
Speaker 2: of the same coin. There was just you're just saying
Speaker 2: that they were equal in magnitude.
Speaker 1: Yeah, they were equal in magnitude, and so the differences
Speaker 1: between them were less apparent, and so it's like even
Speaker 1: more arbitrary to draw a dot line between them in
Speaker 1: the early universe. Now it makes a little more sense
Speaker 1: because like, they are two different sides of the same coin,
Speaker 1: and those sides are quite different, right, I mean they
Speaker 1: still click together into one idea, but the sides are
Speaker 1: quite different. But back in the early universe, it sort
Speaker 1: of made no sense. It's sort of like the Earth
Speaker 1: right again, with the hemispheres. If the Earth wasn't spinning,
Speaker 1: you could split it in any way, it wouldn't make
Speaker 1: any difference. Now that the Earth is spinning around exactly
Speaker 1: one axis and no other axis, there is a north
Speaker 1: and a south hemisphere, right, there is a way that
Speaker 1: makes sense to split it up in the same way.
Speaker 1: Electricity magnetism used to be much more balanced, and so
Speaker 1: drawing a dot line between them really made no sense.
Speaker 1: Now that their symmetry is broken between them, it makes
Speaker 1: sense to draw a line between them, even though we
Speaker 1: still know they're connected.
Speaker 2: I'm not so sure about that analogy. It feels a
Speaker 2: little forced, but I think maybe the overall point is
Speaker 2: that we used to think that we had these two forces,
Speaker 2: electric and magnetic forces, but we figured out they're the same,
Speaker 2: and then it's not the last time it happened, Right,
Speaker 2: Like there was a third force that we thought was
Speaker 2: a separate force, but then we figured out it's also
Speaker 2: part of the same thing.
Speaker 1: Yeah, that's exactly right. The story continues, and again scotsman
Speaker 1: with impressive beards play a big role.
Speaker 2: Is that is that the formula? Is that why you
Speaker 2: have a beard? Yeah?
Speaker 1: Plants and moved to Scotland. I'm really not a fan
Speaker 1: of Haggis, so the whole plan is not gonna not
Speaker 1: gonna work out for me. You're not a fan of Haggis,
Speaker 1: but you're a fan of the Higgs. I'll take a
Speaker 1: bowl of hagges fan, but not a Haggis. I'll take
Speaker 1: Higgs for dinner, but not has.
Speaker 2: You know they're made of the same thing, aren't they
Speaker 2: isn't Hags technically made or has to the Higgs boson
Speaker 2: in it?
Speaker 1: The Higgs gives Haggis its mass, that's true.
Speaker 2: Oh, there you go. And then the Haggis gives your
Speaker 2: stomach its mass and indigestion. It's all in connected. It's
Speaker 2: all part of the same Metichlorian force.
Speaker 1: Yeah, and then you make dark matter the next day.
Speaker 2: There you go. It's all connected me all right. So
Speaker 2: then what's this third force that we ended up unifying
Speaker 2: with the other two.
Speaker 1: So the next force on the list is the weak
Speaker 1: nuclear force. The weak nuclear force is the one we
Speaker 1: think about in terms of the like radioactive decay, where
Speaker 1: the proton turns into a neutron, for example, and shoots
Speaker 1: off an anti electron, or when uranium cracks open all
Speaker 1: of these things. This is due to the weak nuclear force.
Speaker 2: Well, what do you mean? How is it a force?
Speaker 3: Like?
Speaker 2: What's it pushing or pulling?
Speaker 1: So some particles out there have electric charge and they're
Speaker 1: pushed and pulled by electric fields made by other particles
Speaker 1: with electric charges, but not everything out there does have
Speaker 1: an electric charge, like neutrinos don't have electric charge. But
Speaker 1: every particle out there has weak charges. This is like
Speaker 1: another label you can put on a particle. There's actually
Speaker 1: two different kinds of weak charges. It's not a one number,
Speaker 1: it's two numbers you need to describe the weak force.
Speaker 1: Every particle has this pair of weak charges that create
Speaker 1: these weak fields, and these weak fields push and pull
Speaker 1: on other particles.
Speaker 2: Meaning like if I'm a neutrino and I'm flying through space,
Speaker 2: I don't have an electric charge, so I don't feel
Speaker 2: the electric or magnetic forces. But if I come near
Speaker 2: maybe another neutrino or another kind of particle that does
Speaker 2: feel the weak force, what's going to happen? Is it
Speaker 2: going to pull me in? Is it gonna impart some
Speaker 2: velosophy on me, repel me, or track me? Or is
Speaker 2: it something different? Like how is it involved in decay?
Speaker 1: Of particles. So the weak force can both push and pull,
Speaker 1: and it's much more complicated than electricity because it has
Speaker 1: two charges, so you have to know like a combination
Speaker 1: of those two charges. We did a whole podcast episode
Speaker 1: about whether the weak force pushes or pulls. The answer
Speaker 1: is it depends, but it can do both. And so
Speaker 1: the weak field is much more complicated than the electromagnetic
Speaker 1: field in that way, which is very simple. So it
Speaker 1: can do both push and pull. And the fascinating thing
Speaker 1: is that no particle escapes this field. Not every particle
Speaker 1: fields the strong force we'll talk about later, or electromagnetic force,
Speaker 1: but every particle feels the weak force as far as
Speaker 1: we know. Dark matter, if it's a particle, does escape
Speaker 1: the weak force, but every particle we've discovered feels the
Speaker 1: weak force. And ther other question was about radioactive decay,
Speaker 1: like how is the weak force exactly involved in radioactive decay?
Speaker 1: And the answer there involves like the particles that we
Speaker 1: think about in terms of the weak force. For electromagnetism,
Speaker 1: we think about in terms of these fields, or sometimes
Speaker 1: we think about those fields as virtual photons like electrons
Speaker 1: or exchanging momentum using virtual photons we have a whole
Speaker 1: episode about how that happens that came out recently. In
Speaker 1: terms of the weak field, we have three different particles.
Speaker 1: There's two W particles that actually have electric charge of
Speaker 1: their own, and the Z and so particles can decay
Speaker 1: into other particles by giving off a W or giving
Speaker 1: off a Z. When that happens, we say that the
Speaker 1: weak force is responsible. So, for example, if an upquark
Speaker 1: gives off a W boson becomes a downquark, and that's
Speaker 1: what needs to happen for a neutron to decay into
Speaker 1: a proton, then we say the weak force has decayed
Speaker 1: that neutron into a proton.
Speaker 2: I feel like you're saying a lot of words. I
Speaker 2: wonder if some of our listeners are getting lost. I
Speaker 2: guess you're saying, like, maybe the weak force isn't a
Speaker 2: force in the same way that we are used to
Speaker 2: it for electric and magnetic forces. But you see it
Speaker 2: mathematically when things the k or they transform at the
Speaker 2: quantum particle level from one thing to another. Maybe you
Speaker 2: see these other particles popping into existence.
Speaker 1: Well, it definitely is a force. It can push and pull,
Speaker 1: but was it pulling and pushing? It can do it
Speaker 1: for any particle. For example, a neutrino passing through a wall.
Speaker 1: It can get bounced off by an electron or by
Speaker 1: something in the nucleus using the weak force, in fact,
Speaker 1: only using the weak force, because the neutrino doesn't feel
Speaker 1: the electromagnetic force.
Speaker 2: Right, we got that. But when you say it's involved
Speaker 2: in the k what is it pulling or pushing?
Speaker 1: So forces don't just push and pull, right, These are
Speaker 1: interactions between particles that can also transform those particles.
Speaker 2: Well, so that's a different concept. So you're saying a
Speaker 2: force isn't just about pushing and pulling, it's also about transforming.
Speaker 1: Forces are fields that fill the universe or if you like,
Speaker 1: virtual particles, and they also allow particles to transform from
Speaker 1: one kind into another. For example, you can have an
Speaker 1: electron and a positron annihilate themselves turn into a photon,
Speaker 1: and that photon can turn into like a muon and
Speaker 1: an anti muon. Right, that's using the photon, so it's
Speaker 1: using the electromagnetic field. Means the energy of those two
Speaker 1: particles gets dumped into electromagnetic field and then back out
Speaker 1: as in other particles. Again, that's an example of like
Speaker 1: converting one kind of particle into another using the electromagnetic field.
Speaker 2: Oh, I see, you're saying the weak force can push
Speaker 2: and pull things, but it can also kind of act
Speaker 2: like a little like placeholder for energy between particles as
Speaker 2: they transform between things.
Speaker 1: I guess a force turns out to just be like
Speaker 1: a feature of a field. Fields can apply forces too particles,
Speaker 1: but it's not all that they do. You know, like
Speaker 1: your bank will change money, but it also like lends
Speaker 1: it out and does all sorts of other stuff. So
Speaker 1: fields are more complicated than just pushing and pulling on particles.
Speaker 1: The forces are features of those fields, but those fields
Speaker 1: can do lots of other stuff to like transform particles
Speaker 1: and let them interact.
Speaker 2: So you're saying, like the weak force is really like
Speaker 2: let's just think about it as a field. They can
Speaker 2: also push and pull, yes, okay, all right. And then
Speaker 2: later we found out that the weak force is actually
Speaker 2: part of the electromagnetic force exactly.
Speaker 1: And this is the story of Peter Higgs in a
Speaker 1: way that's like kind of amazingly and oddly parallel to
Speaker 1: what happened with Maxwell. That Peter Higgs actually doesn't have
Speaker 1: a beard. I lied. Maxwell is an impressive beard, But
Speaker 1: Peter Higgs, Yeah, and I guess actually, technically everybody has
Speaker 1: a beard. Even if you just shaved, you have a
Speaker 1: tiny little beard, right.
Speaker 2: I think you mean maybe half the population gets beard.
Speaker 1: Yeah, exactly.
Speaker 2: I think you're missing Yes, I think you're missing a
Speaker 2: lot of people here.
Speaker 1: So he was looking at electromagnetism and the weak force
Speaker 1: and he was trying to do the same thing that
Speaker 1: Maxwell did. He's like, can I put these together into
Speaker 1: a larger mathematical framework? Can I click all these complicated
Speaker 1: feels for the weak force and electromagnetism together to make
Speaker 1: a bigger idea?
Speaker 2: All right? And apparently he was able to do that.
Speaker 2: And now we've reduced the number of forces even more,
Speaker 2: And so can we keep doing that? Can we unify
Speaker 2: all of the things we see as forces in the
Speaker 2: universe as one, including maybe gravity question markuee. And so
Speaker 2: let's dig into this big question of unification. But first
Speaker 2: let's take another quick break. All right, we're talking about
Speaker 2: unifying all the forces in the universe, and it seems
Speaker 2: like physicists are doing pretty good. Like we started with
Speaker 2: four apparent forces and now we're down to two apparent forces.
Speaker 2: Because you unified the electric magnetic forces into one, and
Speaker 2: then you modified those two in with the weak force
Speaker 2: to get the electroweak force.
Speaker 1: Right, Yeah, that's right. Higgs connected electromagnetism and the weak
Speaker 1: force by putting them together into a larger idea, and
Speaker 1: in the same way that like when Maxwell tried to
Speaker 1: do that with electricity and magnetism, he noticed a missing
Speaker 1: piece and then went out and found that it was
Speaker 1: actually real out there in the universe. For Higgs, what
Speaker 1: he noticed was it was a missing particle, like these
Speaker 1: two forces didn't actually click together perfectly because you know,
Speaker 1: like the W and the Z, these particles that come
Speaker 1: from these forces, they're very very heavy, and the photon
Speaker 1: has no mass, so he's a little bit of trouble
Speaker 1: fitting them together, which is why he had to add
Speaker 1: a piece, the Higgs boson, and then later we discovered it.
Speaker 1: So it's another example of like mathematics leading us to
Speaker 1: a clearer picture of the physical universe, which is super fascinating.
Speaker 1: And it's also a continuation of that same story we
Speaker 1: were telling earlier about how things come together or are
Speaker 1: more balanced at higher energies because the weak force, why
Speaker 1: is it so weak after all? It's weak because the
Speaker 1: particles that transmitted this field, that carry it is very massive.
Speaker 1: These particles, the W and the Z, are super duper heavy.
Speaker 1: They weigh like eighty or ninety times the mass of
Speaker 1: a proton, which is what makes the force weak.
Speaker 2: Right, which is kind of counterintuitive, right, Like why if
Speaker 2: the particles of it are so massive, why of force?
Speaker 1: Week? You can think about it, like, it takes a
Speaker 1: lot more energy to get this field into play. You
Speaker 1: have to create the wiggles in this field. Takes more
Speaker 1: energy because the field itself has more mass, Like it's bigger,
Speaker 1: so it's lazier. Yeah, it's bigger, and so it's lazier exactly.
Speaker 1: But what happens if you dump a lot of energy
Speaker 1: into this field, Like what happens if everything is moving
Speaker 1: at nearly the speed of light, Then it doesn't really
Speaker 1: matter anymore that the W and the Z have mass
Speaker 1: because you have so much energy, it's like irrelevant, you know.
Speaker 1: It's like if you're a billionaire, then paying your traffic
Speaker 1: tickets doesn't really matter, whereas if you're a normal person,
Speaker 1: paying your traffic tickets can be really expensive. But billionaires
Speaker 1: will just park anywhere because ninety bucks means nothing to them.
Speaker 1: So back in the early universe, when there's lots of
Speaker 1: energy floating around, you couldn't tell the difference between the
Speaker 1: strength of the electromagnetic force and the strength of the
Speaker 1: weak force that had the same strength back then.
Speaker 2: I think what you're saying is like to activate the
Speaker 2: weak force, you need a lot of energy, and so
Speaker 2: that's why it tweak. It's like it takes so much
Speaker 2: energy you hardly ever see it, right, Like two particles
Speaker 2: are like, now, this is too much work to interact
Speaker 2: through the weak force, forget about it. But you're saying,
Speaker 2: like me, at the beginning of the universe, things were
Speaker 2: so hot and so crazy that like the we force
Speaker 2: got activated all the time, which means that it was
Speaker 2: actually not a week exactly.
Speaker 1: And so that helps us bring these things together. Like
Speaker 1: as you run time back together, magnetism joins with electricity
Speaker 1: to have the same strength keep running time backwards. Then
Speaker 1: the weak force joins with electromagnetism. Now those three all
Speaker 1: have the same strength. So this picture of like the
Speaker 1: forces merging together as you rewind time or if you
Speaker 1: think about it forwards, like as the universe cools, it
Speaker 1: sort of like crystallizes and breaks the symmetries, and these
Speaker 1: things crack out in different ways.
Speaker 2: But again it's conceptual because they don't really break apart, right, Like,
Speaker 2: they're still the same and there's still the same math equations.
Speaker 2: They just start behaving differently.
Speaker 1: Yes, exactly. They're not like getting a divorce or anything.
Speaker 2: Right, I mean, it's not like they're transforming into something else.
Speaker 2: It's just like the weak force gets lazier, basically.
Speaker 1: Yeah. But there's sort of analogous to phase transitions. Like
Speaker 1: water is water is water, but sometimes it acts like
Speaker 1: a solid, and sometimes it acts like a liquid and
Speaker 1: sometimes like a gas. So in different temperatures, use different
Speaker 1: rules to describe them, and so as the temperature of
Speaker 1: the universe cranks up, use different laws to describe the
Speaker 1: physics that's happening because there are different phases there.
Speaker 2: But ultimately you can use the same equations for the weak,
Speaker 2: the electric and magnetic force. It's you're saying, like, there
Speaker 2: now there's three sides of the same coin.
Speaker 1: Yeah exactly, And so now we'd like to continue that
Speaker 1: program and also add the strong force, Like wouldn't it
Speaker 1: be awesome if we showed that all these things are
Speaker 1: just different sides of the same four sided coin or
Speaker 1: something that's.
Speaker 2: Pretty the coin there. So let me let's reach out
Speaker 2: for listeners. What is the strong force?
Speaker 1: Yeah, so the strong force is the force between quarks,
Speaker 1: for example. And the strong force, like the other forces,
Speaker 1: acts between things that have its kind of charge. Every
Speaker 1: kind of force has its own charge. Electric forces are
Speaker 1: things that happen between things with electric charge. Weak forces
Speaker 1: are things that happen between particles that have the special
Speaker 1: weak charges. And there is also a strong force with
Speaker 1: its own strong charge. And some particles, quarks, have this
Speaker 1: strong charge we call it color, and other particles like
Speaker 1: electrons and muons and neutrinos don't, so they don't feel
Speaker 1: the strong force. And the strong force is crucial to
Speaker 1: our universe. It's what binds quarks together to make protons
Speaker 1: and to make neutrons and the building blocks of the
Speaker 1: nucleus of the atom.
Speaker 2: And that's where it's pushing and pulling. It's it's basically
Speaker 2: pulling the quarks together, or like if you try to
Speaker 2: separate to quarks, that's the force that keeps them stuck.
Speaker 1: Yeah, exactly, it's what binds quarks together. And we think
Speaker 1: back in the very early universe, there was so much
Speaker 1: energy that quarks were flying around free. We call that
Speaker 1: the quark glue on plasma. But these days, when things
Speaker 1: are pretty distant and cold, everything is stuck together. The
Speaker 1: quarks don't have enough energy to escape those bonds. The
Speaker 1: strong force is very very powerful.
Speaker 2: Ideally, or to keep simplifying things, you want to show
Speaker 2: that the strong force is actually also part of the
Speaker 2: lecture weak force exactly.
Speaker 1: That would be great. Nobody's figured out how to do
Speaker 1: that yet, Like the game that Maxwell and Higgs played
Speaker 1: and we're successful at trying to put these things together
Speaker 1: into a larger mathematical structure hasn't worked so far. Like
Speaker 1: people have tried it and they've jammed them together, but
Speaker 1: it's not really pretty. And the extra bits that it predicts,
Speaker 1: we haven't seen those yet, in the same way that
Speaker 1: we saw the Higgs boson or saw the displacement current.
Speaker 2: Well, what do you mean it's not pretty? What happens?
Speaker 2: You get ugly equations?
Speaker 1: You get ugly equations. Yeah, what we're looking for is
Speaker 1: the kind of symmetry we saw with electromagnetism, Like, oh, look,
Speaker 1: these equations if you write them in this way, they're symmetric,
Speaker 1: it's the same. You can replace electric fields and magnetic
Speaker 1: fields the equations of the same or with the weak force.
Speaker 1: You put them in this larger structure of group theory.
Speaker 1: We show you can rotate one equation into another equation,
Speaker 1: and so the strong force has its own symmetry within it,
Speaker 1: but we can't really click that symmetry together with the
Speaker 1: other symmetries to make it into like some larger machine
Speaker 1: where the gears all rotate nicely and meshed together.
Speaker 2: Well, when you mixed electric and magnetic forces, you figured
Speaker 2: out that there's really just electric charge. When you mix
Speaker 2: the weak force in that you also have to get
Speaker 2: rid of weak charge or that's still around.
Speaker 1: No, that's still around. And you know, we could live
Speaker 1: in a universe with magnetic charge that's not a product
Speaker 1: of the unification. The unification allows for them to be
Speaker 1: magnetic charge. It just so happens to that we've never
Speaker 1: seen one in our universe. It's a mystery. And why
Speaker 1: there are no magnetic monopoles. You don't have to give
Speaker 1: up a charge when you unify.
Speaker 2: And so so now the electric weak force, it's like
Speaker 2: this one equation one force, but it's at the same
Speaker 2: quantum field. Different fields, but they're all somehow connected through
Speaker 2: the equations.
Speaker 1: They're different fields the same way you can talk about
Speaker 1: an electric field and magnetic field. You can still talk
Speaker 1: about the field of the W and the Z, but
Speaker 1: there's a symmetry between them. They're differently part of one
Speaker 1: larger thing, and as you rewind the universe, their strength
Speaker 1: balances together. And one mystery about the strong force is
Speaker 1: that as you rewind time and make things hotter and denser,
Speaker 1: the strong force doesn't get to be the same strength
Speaker 1: as electricity and magnetism and the weak force. It's still different.
Speaker 1: Those two lines sort of don't cross as you go
Speaker 1: back to the early universe, which the mystery is sort
Speaker 1: of like a problem for unifying them.
Speaker 2: Now, I'm wondering if, like the lack of unification here
Speaker 2: with the strong force, does it mean that the strong
Speaker 2: force is totally independent of the other forces. Part of
Speaker 2: the reason you could mix the other two into one
Speaker 2: equation was that they're all sort of, I guess, depend
Speaker 2: on each other, right intertwined.
Speaker 1: They were all intertwined, and we definitely show that they're
Speaker 1: all part of the same sort of larger structure. What
Speaker 1: we'd like to do is do the same thing with
Speaker 1: a strong force, but we don't know, Like maybe it
Speaker 1: really is just its own thing and it comes from
Speaker 1: somewhere else, and the universe has a couple of things
Speaker 1: to it. Right. The whole assumption that you can describe
Speaker 1: everything in terms of one force, well, that is an assumption, right,
Speaker 1: it would be, so what are pretty But it might
Speaker 1: be that there are two forces in the universe, the
Speaker 1: strong force and the electroweak force, and they sort of
Speaker 1: like pushing question PARKI and the question mark these stuff.
Speaker 1: But there is one really other tantalizing clue, which is
Speaker 1: if you add a bunch more particles particles we call
Speaker 1: supersymmetric particles, ones that are partners of our current particles,
Speaker 1: that changes the way all these forces behave and it
Speaker 1: makes it so that if you do rewind time and
Speaker 1: heat up the universe, that the strong force and the
Speaker 1: electroweak force do end up at the same strength. So
Speaker 1: that's sort of like a clue. It makes people feel like,
Speaker 1: oh wait, maybe there's two problems here that solve each other,
Speaker 1: you know, like maybe supersymmetry is real. These particles do exist,
Speaker 1: and they help unify the forces early on in the
Speaker 1: history of the universe. So far, we haven't seen any
Speaker 1: of those super symmetric particles, which has been kind of
Speaker 1: a disappointment, but it would have been awesome because it
Speaker 1: would have helped us unify the strong force with the
Speaker 1: other forces.
Speaker 2: These supersymmetric particles that you just mentioned, they were never real.
Speaker 2: You just sort of like invented them and you try
Speaker 2: to make them work, but they you never saw them
Speaker 2: in a collider or anything.
Speaker 1: We don't know if they're real. They're just an idea,
Speaker 1: and if they exist, they answer all sorts of other
Speaker 1: questions about the nature of the universe, etc. That particle
Speaker 1: physicists are interested in. But they also change the way
Speaker 1: the strong force behaves at high energy in a way
Speaker 1: that make it to have the same strength as the
Speaker 1: electroweak force. That's just like an added bonus. So we
Speaker 1: don't know if they exist, but if they do, then
Speaker 1: they help unify the forces. But we haven't seen them yet, right,
Speaker 1: They've been searching for like decades. Yep, we haven't seen
Speaker 1: any of them. Maybe they're just too heavy, or maybe
Speaker 1: they don't exist. We don't know. I guess maybe the
Speaker 1: larger question is, like why is it important for them
Speaker 1: to be the same magnitude, Like why can't you just
Speaker 1: have a one big one and a little one, or
Speaker 1: why do they all have to be, you know, the
Speaker 1: same strength. They don't have to be the same strength.
Speaker 1: But that's part of the simplification. Like how many numbers
Speaker 1: do you need to describe the universe? Well, it's sort
Speaker 1: of cool if you need numbers. You only need one
Speaker 1: number to describe the electro weak force, Like the very
Speaker 1: strength of the parts of the electro weak force can
Speaker 1: all be explained with how the universe cooled and cracked,
Speaker 1: But you only need one number to define its strength.
Speaker 2: Wait, what do you mean only one number? Like at
Speaker 2: the beginning of the universe the forces were indistinguishable.
Speaker 1: Well, they were part of a larger thing, but you
Speaker 1: only need one number to descrive its strength because they
Speaker 1: were in balance, right, Like magnetism and electricity had the
Speaker 1: same strength at the speed of light. You don't need
Speaker 1: separate numbers for them, And the same thing with the
Speaker 1: weak force, so you could still have two numbers. Like
Speaker 1: that's something I guess you know what I mean? Like
Speaker 1: did something happen in these conditions that make them lose
Speaker 1: a degree of freedom. Yeah, that's exactly the right way
Speaker 1: to think about it. That like you had this unification
Speaker 1: and then it cracked and then broke into two, and
Speaker 1: then you have another degree of freedom. You sort of
Speaker 1: gain a degree of freedom as the universe cools and
Speaker 1: the symmetry is broken between.
Speaker 2: Them, whereas before maybe they were act together.
Speaker 1: It's maybe more what you mean. Yeah, yeah, exactly.
Speaker 2: You know the universe, these forces were all sort of
Speaker 2: in sync.
Speaker 1: Exactly, And we don't think it's coincidence that the strength
Speaker 1: of these forces was the same number back then. They're
Speaker 1: parts of the same thing. To have the same strength,
Speaker 1: that doesn't seem like a coincidence, Right, You don't need
Speaker 1: two numbers to describe one phenomena, especially if the numbers
Speaker 1: are equal.
Speaker 5: Now.
Speaker 2: In terms of making the ultimate progress, which is like
Speaker 2: finding out that even gravity is part of these forces,
Speaker 2: I think scientists are maybe envisioning a time in the universe,
Speaker 2: maybe very close to the big Bag, where maybe even
Speaker 2: gravity was part of these forces.
Speaker 1: Yeah. Maybe we don't know, and it's very speculative because
Speaker 1: we haven't even unified the strong force with electroweek. But
Speaker 1: the idea is that maybe back when the universe was
Speaker 1: so hot and so dense that even gravity, which is
Speaker 1: crazy weak, was as powerful as these other forces. That
Speaker 1: maybe it was all just one. And that's the you know,
Speaker 1: very speculative theory of quantum gravity or theory of everything
Speaker 1: combines the strong force, electroweak and gravity together. But that's
Speaker 1: like double question, markie, I see.
Speaker 2: So what you're saying like maybe a long time ago,
Speaker 2: in a galaxy far far away, there was only the force.
Speaker 2: Is that kind of what you're say as a physicists.
Speaker 1: That's a beautiful idea. We don't know if it's true.
Speaker 1: We've seen the first two chapters, like electricity and magnetism
Speaker 1: join together to make electric magnetism, the weak force joins
Speaker 1: to make electra week. We don't know if the next
Speaker 1: season strong force will unify and if in the sequels,
Speaker 1: you know, gravity comes in to link up together and.
Speaker 2: With the new hope they joined electric and magnetic forces.
Speaker 2: Then the Empire strikes back was the weak force joining
Speaker 2: and then maybe we're still waiting for the return of
Speaker 2: the Jedi engineers. Yeah, exactly, unify the rest together.
Speaker 1: Return of quantum gravity, exactly. And it might be that
Speaker 1: back in the early universe there was only one force
Speaker 1: and then it cracked as the universe cooled and passed
Speaker 1: through the different phases, or maybe it didn't, maybe there
Speaker 1: were multiple forces to begin with. We don't know.
Speaker 2: Well, that would mean that even today, they're all still
Speaker 2: all the same force. They're just you know, acting at
Speaker 2: different levels.
Speaker 1: Kind of yeah, exactly, they all respond differently to the
Speaker 1: universe cooling. But it'd be beautiful we can figure out
Speaker 1: a way to describe them all in terms of one force. Absolutely.
Speaker 2: So what's needed right now more experiments or more theory
Speaker 2: or both.
Speaker 1: Either we're desperate, like either we need new ideas, like
Speaker 1: new mathematical ways and looking at what we've already seen,
Speaker 1: the patterns that we've described, or we need new experiments
Speaker 1: to show us more of the patterns so we can
Speaker 1: get better ideas. We don't know which way is the
Speaker 1: path forward right now, and in the history of physics
Speaker 1: is sort of leapfrogged each other. Experimentalists discover a bunch
Speaker 1: of new particles and nobody understands. Theorists fit them together
Speaker 1: into a new idea and then predict new stuff. Experimentalists
Speaker 1: discover some more stuff. It's sort of gone back and
Speaker 1: forth right now, We don't know which direction is the
Speaker 1: best to make progress.
Speaker 2: It does sound a little desperate, but I wish you
Speaker 2: the best of luck physicists, or as they say, may
Speaker 2: the force be with you, May the force be won
Speaker 2: made the funds keep flowing. All right? Well, another interesting
Speaker 2: conversation about how you know, little by little we make
Speaker 2: progress and making sense of the universe, simplifying the equations,
Speaker 2: making them all work within the same framework. And it
Speaker 2: seems like we've made a lot of progress. But it
Speaker 2: sounds like maybe we've hit sort of a brick wall
Speaker 2: for now, and maybe you just need to force yourself
Speaker 2: through it.
Speaker 1: We need some clever fleas to sit on our shoulders.
Speaker 2: That's right, you just need bigger fleas.
Speaker 1: I'll put them my next grand proposal.
Speaker 2: There you go, make it a clever acronym, Force Leapton's
Speaker 2: Engineering Astronomy.
Speaker 1: Done.
Speaker 2: All right, Well, we hope you enjoyed that. Thanks for
Speaker 2: joining us, See you next time.
Speaker 1: For more science and curiosity, come find us on social
Speaker 1: media where we answer questions and post videos. We're on Twitter,
Speaker 1: disc Word, Insta, and now TikTok. Thanks for listening, and
Speaker 1: remember that Daniel and Jorge explain the universe is a
Speaker 1: production of iHeartRadio. For more podcasts from iHeartRadio, visit the
Speaker 1: iHeartRadio app, Apple Podcasts, or wherever you listen to your
Speaker 1: favorite shows.