StarTalk Radio - Why… Anything? With Harry Cliff

Episode Date: January 21, 2025

Why was there more matter than antimatter left over? Neil deGrasse Tyson and comedian Chuck Nice explore the quantum origins of the universe, charge parity violation, dark matter, and the many quarks that make up our world with CERN particle physicist Harry Cliff. NOTE: StarTalk+ Patrons can listen to this entire episode commercial-free here: https://startalkmedia.com/show/why-anything-with-harry-cliff/Thanks to our Patrons Diedre Austin, Robert R Able, Peter Onnasch, Valarie McCullar, tremayne johnston, Kurt Kwok, Gianfranco Iannotta, April007, Dale Frewaldt, Sergio Castañeda, Desiray Belcher, Steelfinger7 Steelfinger7, Arnav Madan, Jana, Stephan, Craig Cordwell, Emmanuel Nolasco, Micheal Dunthorn, Forgotten Glory, Thornman, Simba vortex, Justus Patrick, Joey Sandall, Ainsley Bhattan, Dan Teston, Nick Smith, Matt Curtis, Todd King, Reka, and Micheal Smith for supporting us this week. Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

Chuck, love me some particle physics. Oh, who doesn't? It's foundational to the world. Yes. And I foresee a day where you walk into your kitchen and they're all just the particles of the universe. Oh. And you just take whatever you need.

Just put whatever you need. And make whatever you want. And make whatever you want, that's cool. And I foresee a day where we will end this matter anti-matter feud. In the octagon. Coming up, all you ever thought you'd care about in the realm of particle physics on Star Talk. Welcome to Star Talk your place in the universe where science and pop culture collide. Star Talk begins right now.

This is Star Talk. Hilda Grass Tyson here, if you're a personal astrophysicist. Chuck, nice there. Hey man, what's happening? Can I say you're their personal comedian? No. Okay. Do not involve yourself with me on a personal basis at all.

Okay. Okay. Take it back. Take it back. Today's going to be a Cos basis at all. Okay. Okay. Take it back. Take it back. Today is going to be a Cosmic Queries. Yeah. Yeah, but not after we learn some stuff. Yeah.

Yeah. And it's good stuff. It's good stuff. Yeah. All right, it's going to be on particle physics. Wow. I didn't know it was going to be that good. Yeah.

You know, I know a little bit about particle physics, but I'm not an expert. Okay. So anytime we hit this kind of impasse, you've got to bring in the expert. And where's sort of best particle physics in the world happening? The collider? The collider?

That's a start, okay. Yeah, it'll be a collider. That's where it's going to happen. We've got someone who's worked at CERN in Geneva. And he's a particle physicist at the University of Cambridge in the UK. Oh dear. Help me welcome Harry Cliff. Harry, welcome to Star Talk.

Harry. Great to talk to you. Thanks for having me. Yeah. So, you worked with the Large Hadron Collider, which is one of the experiments of CERN, and what did you do? What was your role with that? Well, I still work on it, actually.

So the LHC is this massive 19-mile ring buried underground, and there are actually four experiments on the ring. So there are these four places where we smash particles together, and I work on one of them, which is called LHCb, and the B stands for beauty, which is a type of particle

that we're interested in studying. So I still work there, I analyze data, look for places where our current theory might break down or that we haven't found any yet, which is a bit frustrating. Although we're getting some hints, but that's the general job. It's going through loads and loads of data,

trying to find places where we're seeing new effects we've not seen before. But beauty, that's not the names on one of the quarks, is it? It is, yeah, yeah. So there are these six quarks that make up, well, two of them make up the nucleus of the atom, and then there are four others, and they have weird names. So the first two that were found after the original two

were called Strange and Charm, and then the last two, there was this disagreement about what to call them. Some people wanted to call them Truth and Beauty, which is really lovely and poetic, but in. Some people wanted to call them truth and beauty, which is really lovely and poetic, but in the end most physicists call them top and bottom, which is a little bit boring. But because we work on these particles, we study these bequarks, we'd rather be known

as beauty physicists than bottom physicists. So for us at least, it's beauty. It's got my vote. Beauty, yeah. Truth and beauty. I got to say though, I just think, you know, top and bottom might be a bit more interesting in some respects.

Stop, stop. Stop. Stop. Stop. Stop. It's a family show. Okay, all right. And, Harry, you left off the up and down quark.

So, completing the family of six quarks. So we get up and down. Up and down.ark, so completing the family of six quarks. So we get up and down. Up and down. Yeah, that's right. Strange and charmed. Yep. Truth and beauty, top and bottom. That's it?

Top and bottom, exactly, that's right, that's right, six, as far as we know. Maybe there's more, but we've only found six. Okay, so you're a quark man. We gotta love the quark people. And I delighted, just because I reach the public often, that you've written two popular level books. I love it.

And I'm looking at the title of your first one, How to Make an Apple Pie from Scratch, in search for the recipe of our universe. Oh wow. That evokes something Carl Sagan said, which is 1980 Cosmos. Okay. He said, how do you make an apple pie?

He says, start with a big bang. Ha ha ha. Right. So does that inspire this title? Yeah, absolutely. Yeah, that scene, I think it's episode five where he's sitting in, he's actually sitting in Cambridge in Trinity College and this apple pie is brought out to him. And he looks at the camera with a little twinkle in his eye and says, if you wish to make an

apple pie from scratch, you must first invent the universe. And then he kind of goes off to talk about how the atoms in the apple pie were made inside stars. So it's kind of like, it's quite a well-known phrase in physics. I came up like during my university education. So it was kind of, I thought it was a neat way of talking about, you know, what the universe is made from, but through the lens of trying to find out how you make an apple pie, but a really complicated recipe.

Let's get down to basics. Yeah, I was going to say, I'm going to be honest though, it's a long walk around the block to get to an apple pie. From the starting off with it. Good things take a while, you know. But it's cool. 13.8 billion years. It works.

I'm especially delighted by your recently published book, I love this title, Space Oddities, that's very David Bowie of you, Space Oddities. In fact, that was his first hit. Did you know this? David Bowie's first hit was Space Oddity. Oh, okay. Yeah, ground control to Major Tom.

That's what put him on the map. And that's the title. The subtitle is The Mysterious Anomalies, Challenging Our Understanding of the Universe. Ooh, interesting. And it's based on that that we solicited questions challenging our understanding of the universe. Ooh. Ooh. Interesting. And it's based on that that we solicited questions from our audience, from our Patreon supporters.

We'll get to those in a minute. Right. I want to first extract more physics out of you. Tell us more about our inventory of fundamental particles. Are we there yet? Yeah. If we're there, I'll be out of a job. So I really hope there's more. We know about 17 particles in total at the moment.

So there are the six quarks that we've already talked about, two of which make up the nucleus of the atom. Then there's the electron, which goes around the atom. And the electron also comes in this triplet. There are three electron-like particles. The next one's called the muon, and then something called a tau. So that's another three, that gets you to nine.

And then there are three neutrinos, these ghostly particles that zip through the universe and through us and we don't really notice most of the time. So that gives you 12, what we call matter particles in total. Neutrinos are related to the three species of electrons, right, so they're kind of- Yeah, exactly, yeah. Can we think of them as a family? Yeah, exactly.

So the electron has a partner called the electron neutrino, the muon has its own version neutrino, and the same for the tau. So yeah, you've got these 12 particles. I mean, that in itself is a mystery, because they come in these three copies, these what we call the generations, and we don't know why.

It's very mysterious. So it's kind of like we have these Lego bricks in our set, but we don't understand why we have these particular pieces. And then there are the forces. So there are three forces in our quantum description of the world. We don't include gravity. We don't know how to deal with that yet. But we've got the electromagnetic force, the weak force and the strong force, and they each have particles. So the photon is the particle of light that goes with electromagnetism, something called a gluon, which is the particle of the strong force that sticks the quarks together and then the W and Z bosons, which

are the particles of the weak force, which is this weird force related to radioactive processes and other things. 16 in total and then the last one which was found about a decade ago at the LHC, which is the Higgs boson. So that kind of finishes off our 17 particles in what we call the standard model, but we don't think that's the end of the story for lots of reasons, mostly to do with astronomy actually, thanks to you and your colleagues

discovering this inconvenient stuff out there in the universe called dark matter. So that suggests there must be more stuff that we haven't found yet. Interesting. Yeah, whatever dark matter is, we have no idea. And maybe these guys will find it in their particle accelerator.

Right. And if they do, we'd be very happy, because right now, it's just this term in our equations. Right. It's like. But we know it's something. Something's there. Something's there.

So we throw it in the equation. Right. And let somebody else figure out what the hell it is. What the something is. What about dark energy though? Because that's not a particle. Well we don't know. Harry.

Harry. Harry I'm going to throw this one over to you Harry. I mean yeah, no, we have no idea right? We have absolutely no idea. I think it's fair to say. I mean this is when particle physicists try to talk about dark energy, things go really badly wrong. So I should be careful.

But there was this original, well, the idea, one idea for what dark energy is, is what we call vacuum energy. So it's the energy left over an empty space once you've taken away everything else, all the atoms and all the particles. And in particle physics, the actual truth is that particles aren't really the fundamental ingredients of the universe. They are actually made of something more fundamental, which is called a quantum field. For all of these 17 particles we talked about, there is a corresponding field, and the particles

are actually like little vibrations in that field. They're like ripples in an ocean, if you like. So those fields, even when you've got rid of all the particles, they're still there in the vacuum. And if you take, the idea was that maybe dark energy is all the kind of quantum fluctuations that's left over in these fields in the vacuum. But if you run the numbers, you find,

you get an answer that is 10 to the power 120 times too big. So that's 10 with 120 zeros at the end, which is a ludicrously enormous number. If it was that big, the universe would be ripped apart in an instant. So we have no idea what's going on really from a particle physics point of view. So it's the biggest discrepancy ever

between a theory and an observation. However, couldn't there also be something else, since we don't know what that is, couldn't there be something else that's tamping that, tamping the field so that it isn't ripping? Now you're just making stuff up. I mean, that's just as feasible as a field. I mean, no, you're dead right. Like, this is what theorists do. They go, okay, this number's crazy,

so let's add in another thing that cancels us out. That's exactly what people try to do. So, you know, you could be a theoretical particle physicist. This is just perhaps semantics, but of your 16 particles, plus the Higgs boson, and minus the three force carriers, so that takes us down to 13. I think do you count their antimatter

Versions of those particles as separate particles. Yeah, I mean you could you can multiply that number many times So like the quarks for example the version of electric charge for the strong force is called color and Whereas with electric charge is only one type of electric charge in the strong force. There color. And whereas with electric charge there's only one type of electric charge, in the strong force there are three. They're called red, green, and blue. So you get red quarks, green quarks, and blue quarks bizarrely. So that means actually there aren't six quarks, there are 18.

If you add in the anti-quarks that gives you 36. So you can go up to like crazy numbers if you take all these things into account. But basically the antiparticles, they exist in the same field. So you have your electron field. An electron or an anti-electron are just different sorts of vibrations, but in the same fields. We tend to just count that as one thing, not two. And if you start doing that, it gets mad.

Okay, just to clarify that. We were talking about the lifespan of particles before the show and you mentioned. Offline. Offline, offline. And you mentioned that you measured a particle, I don't. It's for his PhD thesis. For your PhD thesis. Measured a particle and the last,

its lifespan was one trillionth of a second. And you said that that was relatively long? Yeah. I mean, there are only a couple of very privileged particles that live forever. There's the electron that we think lives forever and the proton that lives forever. Everything else decays eventually. Even like the neutron, if you have a neutron floating about in space, it will decay in about 15 minutes. So as you get heavier and heavier,

particles tend to decay. Interesting. Yeah, 15 minutes, that's it. If you break off a neutron and set it free, 15 minutes later, it just goes, it goes. Well, it turns into a proton and an, no, you tell me, what are the decay products of a neutron? It turns into a proton, an electron,

and an anti-neutrino. You get three things out. Ah, gotcha, okay. And here's something cool. I want to show off the little bit of particle physics I know, okay? You hear what he said. Your neutron becomes a proton, an electron,

and an anti-neutrino. Anti-neutrino. Okay, now watch. The kind of particle the neutron is, you can't end up with something that isn't that kind of particle when you're done. Okay, it's conservation laws. It's okay for the neutron to become a proton,

but wait a minute, the proton has a plus one charge. Right, so now you gotta cancel that out. Cancel that out. Cancel that out. We cancel that with a what? Wait, the proton has a, oh, the, oh, wait, wait, the proton, so it's a proton. Plus one. Plus one.

Who's got a minus one? That's electron. Electron, boom! He said electron. And he said electron. So those cancel, we're good, however, we now have an electron that's a kind of particle that we didn't start with. We gotta undo the fact that we now have an electron. Oh, because you gotta need the conservation.

You gotta concentrate on this. So now. How do you get rid of the fact that we now have an electron. Oh, because you gotta need the conservation. You gotta concentrate this. So now. How do you get rid of the fact that you now have an electron? And the electron is paired up with these neutrinos, and what'd he say? You not only get the electron, you get the?

Anti-neutrino. Anti-neutrino, canceling out the electron. Now that's a great way to balance this out, but my question is, do these things, are these things actually here? Or are you just saying, okay, we need this to cancel it out? Well, take us there.

Were these hypotheses that we require of the universe, or were these observations that the universe requires of us? Ooh, that was a good one. That was a good one. I liked it, I liked it a lot. Well, I mean, I guess it goes back to 1896. So, Henri Becquerel, French physicist, famously discovered radioactivity in his lab

when he left these uranium salts on top of a piece of photographic paper. And he saw that even when there was like a bit of card in between the salt and the paper, the photographic film got exposed. So, that was what he was seeing there were neutrons decaying into protons, basically. That was the radiation that was being emitted by those uranium salts.

So we kind of knew about this process. It was called beta decay back in those days. And then Ernest Rutherford and others studied it in the late 19th century. So we kind of knew about this process way before we even knew what a neutron was. That took another 40 years or so. So the phenomena appeared first. It took a lot longer to actually figure out what was neutron was. That took another 40 years or so. So the phenomena appeared first, and it took a lot longer to actually figure out

what was going on. The beta particle was the electron, correct? Yeah, exactly, that's right, yeah. Because at the time, we didn't know about neutrons. Neutrons would come, we didn't know about neutrons until 1930, so we had to have clumsy other language to account for this. Okay.

Yeah, so you're saying that the universe is requiring it of us to recognize these properties and they become rather helpful, correct, in calculations you do and in predictions you make. Yeah, I mean, the whole subject of particle physics is kind of built on this idea of mathematical symmetry, these symmetries that are either respected or broken and that generates this very powerful mathematical description

of the universe. And I mean, this way of looking at the world is extraordinarily successful. Like to give you an example of how amazing this theory is, there's one quantity that we can, one example of a quantity you can use to calculate is the magnetism of the electrons. The electron, as well as having an electric charge,

it behaves like a little magnet and limits a magnetic field. And you can calculate how strong that little magnet should be to one part in, I think now 10 billion. And if you do an experiment, a really, really precise experiment, you get the same number to 10 decimal places, which is crazy.

So this kind of way of looking at the world is incredibly powerful. About the same time, we know we're massively missing something because we don't know what dark matter is or dark energy or any of this other stuff. So it's this amazingly successful theory, but also incomplete. Yeah, you know enough about the universe

to quantify your ignorance. Yeah, I'm going to say, yeah, without a doubt. Anything you get to ten places, you pretty much nailed it. Yeah, you nailed it. You nailed it. I'm Jasmine Wilson and I support Star Talk on Patreon. This is Star Talk with Neil deGrasse Tyson.

Let's go to our questions now. You got it. By the way, they were our Patreon supporters. These are patrons of StarTalk. They are occasionally solicited for questions they might have, specifically tuned for the guest. So you're not in studio with us, you're coming to us from London,

but that doesn't matter to the questioner, they don't care where you are. All right, that's what you got, Chuck. He says, hi, StarTalk team, Andrew here from Cork City, Ireland. Dr. Cliff, can you please explain how your research on CP violation in B. Masons contributes to our understanding of the matter anti-matter asymmetry

in the universe. Thanks a million. I like that. Let me tee this up. Okay. Because I can do the astronomy part of this and then he can go in to the particle physics part of it. Right? So you look in the early universe,

you have matter and there's energy there, and matter and energy we know are equivalent, and from this bath of energy, you can spontaneously make particles. And if you do that, the laws of symmetry of the universe say the particles are matter-antimatter pairs. They came out of nothing, you gotta be able to come back together and be nothing again.

And be nothing. Again, okay, so you got the, and this is just going on, okay? And, but, at some point, the universe, out of this soup of energy, created one extra matter particle for every 100 million particles that it made. And so in the dance-off, all the pairs go away.

So that's annihilation, annihilation, annihilation. And there's one person left, and he's got nobody to annihilate with. That is everything we know and love in this universe that we call matter. So wait a minute, all matter? Yes, from that one. Wait.

Yes, yes. All matter? Yes, yes, everything else is a photon. Everything else turned into energy. From this leftover, just the one out of 100 million It's all matter. Yes, yes, everything else is a photon. Everything else turned into energy. From this leftover, just the one out of 100 million playing musical chairs. In the musical chairs, everybody pairs off,

and they're happy, and then you think everybody's paired, and then one person is left, and there's no one to pair it with ever more. And that makes up everything. All the matter that we love and know in this universe. So Harry, why did you do this? What? I mean, I wish I could claim responsibility

for the existence of the universe. Well, I mean, yeah, this is a big problem, as you say. Because we see this in experiments. When we bang particles together at the Large Hadron Collider, you always see equal numbers of particles and antiparticles being made. So this is what happens. So the question is, how did you get this asymmetryetry and there was a Russian physicist back in the 70s?

I think called Andrei Sakharov who came up with three conditions that had to be satisfied To allow matter to win this battle with antimatter in the early universe The first one pretty obviously is you need a process that makes more particles and antiparticles. That's number one the second one though is this condition known as CP violation, so obviously, is you need a process that makes more particles than antiparticles. That's number one. The second one, though, is this condition known as CP violation. CP stands for charge parity, which is a sort of symmetry that relates matter to antimatter. It's kind of like a mirror. If you put matter in the CP mirror, it shows up as antimatter.

What we're looking for are processes that violate this symmetry. These B mesons that the questioner asked about, these are particles which contain a beauty quark and another quark, paired up with an anti-quark usually. There are a particular type of these particles that do this really weird dance where you create one of these B mesons and as it travels through your experiment, it oscillates backwards and forwards between matter and antimatter, so it will flip its identity with this very nice periodic way. What you then do is you watch how often does it decay in the matter state and how often does it decay in the antimatter state, and you measure the difference.

If you see a difference, that tells you that the laws of the universe violate this CP symmetry, this symmetry between matter and antimatter. So this is the kind of key ingredient, one of the key ingredients we need to explain this mystery. The universe has the power to violate its own laws by this process. Yeah, exactly. So this was first discovered, I don't know,

back in the 80s originally, and we're studying it in lots of different particles now. So we know that this Cp symmetry is broken, which is a good thing, because if it wasn't, we wouldn't be here. But the mystery is, our current particles we know about don't break it enough. So the symmetry is only very slightly broken,

and we need way more of this symmetry breaking to explain the fact that we exist and the universe is there to look at. I didn't know we had any mechanism at all to explain the fact that we exist and the universe is there to look at. I didn't know we had any mechanism at all to break the symmetry. I'm, my cockles are warmed by this knowledge. Wow.

Okay, next question. That is fascinating stuff. Good one. Okay, this is Sauron Sarkar, friend of ours. Is matter, anti-matter asymmetry the cause for the Big Bang? We just talked about it, but could that, I mean, are you going to make a Big Bang, man? Yeah, yeah, what are you hiding from us?

Yeah. Astrophysically, it happens much later than the formation of the universe, but with your Large Hadron Collider, you are probing the conditions that would have prevailed at the Big Bang itself, or very close to the very beginning. So do you think that this, I'm re-wording this question, that this matter, anti-matter asymmetry

would have mattered before it otherwise mattered astrophysically in the universe? I mean, it's not, we don't really know when the process that broke this symmetry happened. The LHC, as you say, is kind of recreating the conditions of the Big Bang. We're probing conditions that existed about a trillionth of a second after time zero, if there was ever such a thing. That's kind of where we are.

There is a possibility that that was the moment. It's all actually related to the Higgs boson. There was this thing that happened about a trillionth of a second into the universe's existence called the Electroweak Symmetry Breaking, which is basically where the Higgs field, which gives mass to the particles that we're made from, switched on for the first time. That reset the laws of, well, reset the basic ingredients of the universe, set the form of the forces.

It was a transition a bit like water boiling. It's like a kind of, like a change of state, but a change of state of the vacuum itself. And that may have been the moment which created more mass than antimatter. And that's why we're doing, one of the reasons we built the LHC is to recreate those conditions,

to see if we see that process happening. These phase transitions, you said water boiling, going from just regular water to boiling, or even freezing, right? Water going, it's water completely changing its state. And you now use this vocabulary sort of loosely in the early universe, or maybe literally, the universe is changing its state of existence.

Are you just saying, if it's going to happen anywhere, that's where it's going to happen, because that's where there's some serious action going down the pipe. Yeah, I mean, it's, well, theoretically, you can, when you do the, you sort of figure out what this event looked like, under certain conditions, you find in the equations of the standard model

that you can make more particles than antiparticles. In certain, this phase transition has to happen in a very particular way, and you actually need of the Standard Model that you can make more particles than antiparticles in certain... This phase transition has to happen in a very particular way, and you actually need more particles than exists in the Standard Model. So the Standard Model on its own can't do it, but the Standard Model plus some other things can do it. But it's also possible it happened earlier. So we're talking not a trillionth of a second after the Big Bang, but a trillionth of a trillionth

of a trillionth of a second. So you're getting closer to time zero. That helps me become more accepting of the fact that you can blame these transition, you can blame all the weird oddities that are going on on these transitional moments in the universe, right? Because that's where stuff is going down. Right, okay. Excellent. Time for a couple more.

What do you got? All right. You know, I'm going to go to Magnus here. Says, Magnus. I am Magnus, son to a fallen father, husband to a murdered wife. I am Magnus, and I shall have my revenge. Okay, I'm sorry.

Did that just come out of you? Yeah, I don't know. It just sounds like what you should say. Well, your name is Magnus. Your name is Magnus. You know? Clearly, the plight of Magnus. Okay.

All right, he says, my respects, Dr. Cliff. May you describe the link, as you see it, between A, quantum field theory as the gold standard of the standard model until now, a perfect description of our current knowledge, B, various versions of quantum gravity, i.e. string theory and loop quantum gravity, which depend on the ADS-CFT

duality with or without background dependency. And just to add, I'm a Swede in Switzerland confusing, no? What? Sorry. Okay. So how? It's only confusing to Americans, okay, Magnus? Because. So what is that question?

I don't get the question. Go ahead. So Harry, did you follow the question? Did you follow the question? I think so. I think they were asking about, well, the relationship between quantum field theory, which is the language of the Standard Model,

the language of particle physics, and string theory and loop quantum gravity. I mean, I think that was the question. I mean, what I would say is that I am really underqualified to talk about quantum gravity, not my area. I think the... But what I would say is that quantum gravity theories, they say very little about particle physics at the moment.

So string theory, loop quantum gravity, whatever your favorite flavor of quantum gravity theory is, it has no bearing on any experiments that we do in high-energy particle physics at the LHC. One of the big problems with these theories is they don't really make testable predictions so far. I would love it if string theorists or someone else could come along and say, if string theory is right, you can do this experiment at a collider and you'll see this, but so far that hasn't happened. Really, quantum field theory is the gold standard. It's the theory that works. Maybe it'll be replaced by one of these theories later, but I think we're a ways from that.

Interesting. Alright, so what he says, he doesn't care about gravity. Really? I'd love to include gravity. I'd love it, but it's a hard problem. Currently, what is our best understanding of the most things going on in the universe? Is it just sort of quantum field theory? Is that what gives us the best understanding of the most things going on in the universe? Is it just sort of quantum field theory?

Is that what gives us the best understanding of everything and maybe we'll just have to modify that? Or is there something else ready to take over all of it? Waiting in the wings, an umbrella to it all. Yeah, I mean, as you know, like in modern physics, we have these two pillars of, which describe pretty much everything in physics, which are quantum field theory, on the one hand, which describes particles, quantum mechanics, you know, all that stuff.

And then we have gravity on the other on the other hand, in general relativity, which is a classical theory, a non quantum theory. And so you have these two separate theories, but they, they actually don't really overlap with each other. I mean, the only places where you would see quantum gravitational effects are at the center of black holes or at the very earliest moments of the Big Bang, these really extreme conditions. For everything else, these two separate theories

work perfectly well. So that's kind of the problem actually, because the only place you get evidence for quantum gravity are in these really extreme conditions, which we're way, way away from being able to recreate in the laboratory. So that's what makes it very difficult. Cool, man.

Okay, all right, give me another. Here's another one. This is Friedrich Johansson, who says, hello, Friedrich here from Northern Sweden. What do you think? Friedrich, I'm up in the hood. Right. Hello, Friedrich here from Detroit.

No. No. So he says, Friedrich here from Northern Sweden, do all fundamental particles of a type have exactly the same mass? And how can we know that? Oh, I'd love that. It's a know that? Ooh, I love that. That's a really cool question.

I love that. Yeah. So are all particles of any species identical in every way to the limits of all measurements? I mean, well, because you can measure it, right? So, yeah, every electron is exactly the same as every other electron. Every proton is exactly the same as every other electron. Every proton is exactly the same as every other proton.

The reason is, well, protons are a bad example actually, but say electrons. The electrons are actually made of this thing called the electron field, which is an invisible fluid-like thing. It's all throughout the universe, and every electron is a little ripple in this same field. As a result, when you hit the electron field, you make an electron, you make the same type of thing everywhere. So that's why they're identical. I mean, you can almost, you can always argue that every electron is the same thing.

It's part of the same object. So every particle of a certain species is absolutely identical and indistinguishable. And that's really fundamental actually to our understanding of particle physics and quantum theory. Is it a borg like that? Yeah, that is the borg. All the members of the borg, they're not is the visual. Cons't a borg like that? Yeah, that is the borg.

All the members of the borg, they're not is the visual. Conscious-wise. Conscious-wise, yeah. They're all, they're all one entity. They're all one entity. Although electrons don't come along and try and turn you into an electron. Oh, okay.

All right. Good, Star Trek geek. Yeah, I am Locutus of electron. Resistance is futile. But part of the question was how do you know, because you haven't measured every electron in the universe, and you're saying you know enough about the field to know that there's only one kind of particle it can make in that case, and therefore you're going to get

the electron every single time. That is really cool. Yeah, yeah, yeah. Oh man, okay. Yeah, no, yeah, yeah. Oh man, okay This is Yazan Al-Hajari, and he says, cheers from New Jersey. I'm Yaz, an artist and filmmaker studying relativity. I'm fascinated by how Einstein's theory is applied to the Large Hadron Collider, where particles approach to the speed of light.

Dr. Cliff, could you explain how relativity shapes our understanding of these high energy collisions and whether it might someday be possible to safely create a small black hole somewhere in the Collider? And Neil, if that were possible, would you like to throw something into that black hole? Totally, oh yeah.

We can make it like an amusement park game. Hit the black hole, and it just disappears into the singularity. That question reminds me of earlier in our conversation. So, Harry, you studied particles that decayed in a trillionth of a second. It seems to me that can be a trillionth of a second only at a certain speed,

because the faster a particle goes, the longer it would take to decay, because its time frame has shifted relative to the observer. So you can't just declare a trillionth of a second without specifying a speed, or is that that particle at rest? So that trillionth of a second is from the particle's point of view, so in the frame of the particle, so the particle's at rest, basically.

So if you were the particle, you'd live a trillionth of a second. But from our point of view in the lab, as you say, these things are going close to the speed of light, so they live way longer. So they actually will travel, they live long enough because of this relativistic time dilation to fly a centimeter or so

in the experiment, which if they just live a trillionth of a second, they wouldn't go anywhere near that far. So you're absolutely right. I mean, like, relativity, special relativity, I should say, is fundamental to colliders, because what they basically do is, they are E equals MC squared machines.

They take E energy, kinetic energy, in these accelerated particles, they bang them together, and they make M. They make new particles, new matter effectively. So like it's absolutely fundamental to what we're doing. But the question about black holes, that's really general relativity. And there were some ideas back when the LHC switched on that if there were extra dimensions of space, so extra directions that you can move in, that it would be possible to create microscopic black holes

at the LHC. This led to a load of tabloid stories about the LHC is going to create a black hole, it's going to swallow Geneva and then swallow the rest of the planet and we're all going to disappear. This caused such a big storm in the British tabloid press actually really got hold of this story. CERN had to create this health and safety report, which is the most exciting risk assessment you'll ever read.

It basically describes these various hazards, one of which is a black hole that swallows the earth. The other is the creation of a bubble universe that expands to destroy the entire of reality. They had this risk assessment where the destruction of the universe was one of the possible outcomes. They basically said, this is very unlikely to to happen and so it's all fine. It's unlikely. And you still got money. They gave you, they still let you do it.

Well, no one's going to sue you if you destroy the planet, right? Right, right. He's already thought this through. I am telling you. So there's a YouTube video before the Large Hadron Collider was turned on, but there was a countdown to it.

There's a YouTube video of the parking lot outside of CERN, and you have the clock counting down, and then it gets to zero, and then the parking lot falls in. On itself, wow. And the whole, it's pretty funny. Terrifying. Yeah, I was going to say,

it's funny if you're an astrophysicist. For the rest of us, it's not funny. I should say, there is a reason why we knew this wasn't going to happen, For the rest of us, it's not funny. I should say there is a reason why we knew this wasn't going to happen, and that's because the universe has been doing this experiment for billions of years where we have protons that hit the upper atmosphere much higher in energy than the LHC.

So if this was possible, every object in the universe would have been turned into a black hole. So we kind of knew for that reason that it wasn't going to happen. All right. Right, there's no greater particle accelerator than the universe itself. Than the universe itself?

Ooh, look at that. All right, all right. This is Viper who says, hello, Dr. Tyson, Dr. Cliff, Lord Nice. I am Sam from Othallan, Missouri. I am 16 and have been wondering about tachyons for a few years now. I would like to- wondering about tachyons for a few years now. I would like to know more about them.

And if you guys can go into more depth explaining what is the deal with tachyons. Oh. Wow, okay. Yeah, I mean, well, all I really know about tachyons is they're hypothetical particles that travel faster than light, but I don't about tachyons is that hypothetical particles that travel faster than light But I don't think they're allowed to exist because they would violate causality

This idea that like one event leads to another and not the other way around So they are I think there are things you can kind of cook up in your equations, but they're basically forbidden They turn up in Star Trek. I think all like, you know science fiction as a way of like Facilitating time travel, but all the time. But I don't think that there are things that can exist in reality. But maybe Neil may know more about this than me.

Well, let's see what Merlin has to say about this. Dear Merlin, what is a tachyon? Rick McFarlane, Dallas, Texas. Tachyons are hypothetical particles that travel faster than the speed of light. Named for the Greek, tachis, meaning swift, where we also get the word tachometer. Einstein's equations of special relativity

bestow this particle with an array of bizarre properties. Here are the top five. One, the slowest a tachyon can move is slightly greater than the speed of light. Two, a tachyon can have infinite velocity. Three, when a tachyon loses energy, it speeds up. When it gains energy, it slows down. A tachyon appears to travel backwards in time

for some observers. If you send your friends a message with a tachyon, they can receive the message before you sent it. Tachyons have yet to be detected. There you go. There's the end. That'd be useful for those emails that you forget to reply to, right,

that sit in your inbox for weeks, and then if you could send them back in time, that would be amazing. Yeah, and my favorite tachyon account would be, you see someone walking down the corridor, and then they slip on a banana peel. But he's your friend, then you don't want them to be harmed. So you go to a Tachyon texting app, okay?

And you, because it's already happened, so you send them a text and say, watch out for the banana peel. So then they get the text before they step on the banana peel. Okay, so now the person's walking down the corridor and they get a text. And they look at the text and it says,

watch out for the, and they slip on the banana peel. And they slip on the banana peel. Because they're not looking. Because of your text. Because of your text. Right. There it is. Chuck, we've got time for one, maybe two more questions.

Actually, let's go with Jonas Dravland. And Jonas says, good morning, Dr. Cliff, Dr. Tyson, and Astro Lord Nice. Okay. Okay. Jonas from the Appalachian foothills of North Carolina, here, is there any dark matter in my living room? Or, stated more seriously, is dark matter scattered throughout the universe,

or is it all in clumps around distant galaxy clusters? If it is present on Earth, does that allow one to search for it in settings such as your collider, sir? Oh, I love it. Well, thank you, Jonas. What a great question. When you live in the hills of the Appalachian, you got a lot of time on your hands.

Yeah, he's taking hikes and thinking about dark matter. Yeah, so what you got there? I mean, there's definitely, there would be dark matter in your living room, yeah, for sure. Because we, well, this is actually really astronomy rather than particle physics, but the idea is that every galaxy like our own sits in this big spherical cloud of dark matter and the galaxy is kind of in the middle of this cloud.

So if there are dark matter particles floating around in the galaxy, they're floating through us and through the earth and then there'll be a few in the room. It depends on how massive they are as to how many there would actually be, but yeah, they'd be there. And that doesn't actually help us at the LHC because at the LHC we're trying to make them out of energy. But there are other experiments that go live down big mine shafts where you have tanks of really cold xenon or other kinds of noble gases and you wait for a dark matter particle

to drift through the earth, hit a xenon atom in your detector and create a little flicker of light and then you directly detect dark matter. So it's a bit like a poltergeist moving, throwing some crockery around in your living room. That's kind of what we're waiting to see. But these detects are getting more and more and more sensitive. They still haven't seen anything,

which is very frustrating. But hopefully one day they'll pick something up. Last question. All right, this is David Smith. He says, hello, Dr. T, Dr. C, Lord Nice. Dave Smith here, hailing from Naples, Florida. How do you know you have found anti-matter if anti-matter and matter cancel each other out?

Is it the violence of the inner action, the aftermath, or the moment of ever so slight when you see the matter and anti-matter just before their epic confrontation. So he made it into a boxing match. He's the Don King of particles. Particles in the octagon. Exactly.

Two particles enter, one particle leaves. No, no, in this case, two particles enter, no particles leave. Oh, that's a real good fight. That's a real good fight, yeah. An antimatter particle out in the wilderness, can you identify it as such unless you then see it annihilate? You can, yeah.

And actually, the way it was discovered originally was by Carl Anderson, American physicist back in 1932. So he had this thing called a cloud chamber, which is this amazing instrument that allows you to see individual subatomic particles. They basically create these trails of water droplets as they go through the chamber, which you can see as little traces. He had one of these chambers at Caltech in California, and he was seeing cosmic rays

coming from outer space. You see electrons, you see protons, and he had magnetic field on his chamber. He saw one track that looked just like an electron. It had the same kind of form, but it was bending the wrong direction. So it was an electron with positive charge. That one photograph was enough for Anderson to say, I've discovered antimatter. Now at CERN, there's a really cool experiment called ALFA, where they actually make atoms of antimatter. They make antihydrogen, and they trap make atoms of antimatter.

They make anti-hydrogen and they trap it in a magnetic bottle. You can't obviously keep it in a bottle because it would annihilate the bottle. If you have a really strong magnetic field, you can store these things and keep them stored for hours now. Then you can shine light on them and look at spectroscopy and all kinds of really cool stuff. We can actually effectively store this stuff in very small quantities now. So anti-hydrogen would be an anti-proton

with an anti-electron in orbit around it. Yeah, if you get a chance to go to CERN, you should visit the Alpha experiment, because it's awesome. And just in all, in the interest of disclosure regarding Carl Anderson, the existence of antimatter had just been predicted, okay? That was Fermi, correct? Direct, direct.

Direct, direct, thank you. There was some framework to even be able to interpret that result. And there was, electron doing the opposite for its charge. But otherwise it was identical to an electron. Same mass, same everything. That's pretty cool. Yeah, that was very cool.

Yeah. Very cool. Who knew I had a twin? An evil twin. An evil twin. Why does that twin have a goatee? That's right. That electron has a goatee.

What's going on? That's the comic strip. Right. The anti-matter comic strip that we need. All right, well listen, Harry, thank you for being on Star Talk. We love what you do and we love how you talk about it. And now that you're in arm's reach,

I'd love to come back to you when we have particle physics questions. Yeah, I'd be happy to. It was great talking to you, really good fun. Do you have a presence on the internet? Do you have a handle that people can track you down? I do, yeah. You can find me at my website, harrycliff.co.uk

if you want to see what I'm up to. I'm also on Twitter or X or whatever we're calling it, at harryvcliff. And your latest book, The Mysterious Anomalies, Space Oddities, The Mysterious Anomalies Challenging Our Understanding of the Universe. Nice. And there aren't many books about what we don't know,

and this is just that kind of book, the things that are, that's odd, what's that? You know what, I could write that book. You can? I could write a whole book on what I don't know. I'm telling you right now. But you know, scientists love things we don't understand. That's how science makes progress, and that's what the book's about.

It's about all these weird little effects that could be nothing, or they could be the clue to something really big, and we're sort of trying to figure that could be nothing, yet another installment of Star Talk, Cosmic Queries, Particle Physics Edition.