Our World of Particles with Brian Cox

How much more physics is out there to be discovered? Neil deGrasse Tyson sits down with physicist, professor, and rockstar Brian Cox, to discuss everything from the Higgs boson, life beyond our planet, and the fundamental forces that guide our universe.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Neil deGrasse Tyson?

  Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:15Neil deGrasse Tyson?

  This is StarTalk. Neil deGrasse Tyson, you're a personal astrophysicist, and today we are featuring my exclusive one-on-one interview with my friend and colleague from across the pond, Brian Cox. Brian, welcome.

• 0:30Brian Cox?

  It's great to be back.

• 0:31Neil deGrasse Tyson?

  Oh, my gosh. Oh, it's been too long.

• 0:34Brian Cox?

  Yeah, and we don't usually get to do it in person. It's usually over Zoom or something.

• 0:38Neil deGrasse Tyson?

  Right. Let's get some of your biography out there for stateside people who might not fully know who you are. You cut your teeth as a particle physicist, is that correct?

• 0:48Brian Cox?

  Yeah, initially. I mean, actually, my degree is the University of Manchester, by the way, in the UK. I've never left. So I started there doing my undergraduate degree, postgraduate.

• 0:56Neil deGrasse Tyson?

  What do they call you there now? You are professor of particle physics at the University of Manchester?

• 1:02Brian Cox?

  Yeah.

• 1:02Neil deGrasse Tyson?

  And Royal Society, as in the Royal Society of London?

• 1:06Brian Cox?

  Yeah.

• 1:07Neil deGrasse Tyson?

  Royal Society professor of public engagement in science.

• 1:10Brian Cox?

  Yeah.

• 1:10Neil deGrasse Tyson?

  So we're kindred souls across the Atlantic.

• 1:13Brian Cox?

  Yeah.

• 1:13Neil deGrasse Tyson?

  So, okay, so you never left. Is that because they wanted you so badly, or that no one else wanted you?

• 1:18Brian Cox?

  Yeah, probably the latter. But I started, it was actually physics with astrophysics, my degree. So I did a degree in physics with astrophysics, then PhD in particle physics, although the first year was I was working on supernova neutrinos. So I was crossing over astroparticle physics, as we would call it. Then I got into particle physics, went to the Daisy Laboratory in Hamburg and worked on electron-proton collisions, so called diffractive scattering.

• 1:46Neil deGrasse Tyson?

  I've seen Daisy online, I've seen Daisy simulations of things. They simulate like colliding black holes and things. Fascinating. Daisy.

• 1:55Brian Cox?

  DESY, the Deutsche Elektronosynchrotron.

• 1:58Neil deGrasse Tyson?

  Yeah, they have a public facing platform.

• 2:02Brian Cox?

  See, I didn't know that. I didn't know. Because the accelerator is no longer operational there. But it's a big, it's a huge lab in Hamburg. So I did my PhD there, that's in particle physics, then moved to Fermilab in Chicago for a while, and then to CERN when we were building a large hadron collider. And then, but I've always...

• 2:22Neil deGrasse Tyson?

  CERN Switzerland, yes.

• 2:23Brian Cox?

  In Geneva.

• 2:24Neil deGrasse Tyson?

  And remind me that's... The European Center for Nuclear Research.

• 2:29Brian Cox?

  Research.

• 2:30Neil deGrasse Tyson?

  Yeah. Acronym, French acronym.

• 2:33Brian Cox?

  Yeah, because it was founded in the 1950s. And at the time, so it was, it was what part of the reconstruction of Europe really after the war. So it was a, that lab was founded, I think it was 1954, 1953. And so was nuclear physics at the time. There wasn't really such a thing as particle physics, I suppose, at the time. And then, and now it's by far the world's largest accelerator, particle physics lab.

• 2:55Neil deGrasse Tyson?

  Yeah, I mean, the center of mass of that whole world left the United States when we stopped funding our super.

• 3:01Brian Cox?

  The SSC in Texas.

• 3:03Neil deGrasse Tyson?

  Yeah.

• 3:03Brian Cox?

  The SSC, superconducting super collider.

• 3:06Neil deGrasse Tyson?

  Supercollider.

• 3:07Brian Cox?

  Yeah.

• 3:07Neil deGrasse Tyson?

  Yeah, I would have called it the super duper collider that might, might have kept its funding.

• 3:12Brian Cox?

  Yeah.

• 3:13Neil deGrasse Tyson?

  At that point, but yeah, so Europe still leads the world in, in nuclear particle research.

• 3:20Brian Cox?

  It's, it's, it's a very international lab. I mean, it is the world's collider. So, so although it's based in Switzerland and France, I would say it's a, it's a world lab.

• 3:31Neil deGrasse Tyson?

  Okay, that's very diplomatic of you.

• 3:33Brian Cox?

  Well, it certainly is. I mean, the US has a tremendous presence there, for example.

• 3:37Neil deGrasse Tyson?

  While you're saying all this to me, you're not describing this, this branch of your life as a musician. So just briefly remind me of that.

• 3:47Brian Cox?

  Yeah, so when I was 18, so traditionally you would go to university there, start a physics degree. But I didn't because I was in a band, a rock band that I joined just before.

• 3:57Neil deGrasse Tyson?

  I'm sure your parents loved that.

• 3:59Brian Cox?

  They, no, they did, actually. They, they, they loved it.

• 4:02Neil deGrasse Tyson?

  I could go to college and major in physics or continue with my band.

• 4:06Brian Cox?

  Well, but do you have that thing like a gap year, we call it, where you say, well, I'm going to take a year off the studies before I go to college or university. And so I'd said that, I'd say, I'm going to be in this band and I'm just going to do it for a year and then I'll go and do physics. But then we got a record deal. A big record deal with A and M Records. This is in nineteen eighty six, nineteen eighty seven. It's a long time ago. A big record deal. And so we, I came to Los Angeles and recorded an album with a, actually produced by Larry Klein, who was married to Joni Mitchell at the time. And so we recorded some of it in Joni Mitchell's studio in Los Angeles. So then we toured with, my first professional gig with that band was with Jimmy Page, the fourth Jimmy Page.

• 4:49Neil deGrasse Tyson?

  Did you open for Jimmy Page?

• 4:51Brian Cox?

  Yeah, we opened for Jimmy Page and Gary Moore, who'd also been in the band, Thin Lizzy, and then Europe, The Final Countdown. So you know this song, The Final Countdown, and Carrie was a big hit here in the US. So we opened for them, made a couple of albums. So I did that basically for five years.

• 5:07Neil deGrasse Tyson?

  And it charted?

• 5:08Brian Cox?

  Actually, no, we just, we did big shows. It was a rock and roll band. And then, and then we, I left that band, went straight back to Manchester and went to start a physics degree.

• 5:20Neil deGrasse Tyson?

  As one would do, yeah.

• 5:21Brian Cox?

  But then in that little gap, that I joined another band who then had some hit records. So a band called De Ream, this is in the early nineties now. And we, they didn't have a record deal when I joined them, and they got a record deal as well. So when I was at university, I was in this band. We had a number one hit in the UK and Australia with a song which violates the second law of thermodynamics, which you'll love, called Things Can Only Get Better, which is clearly incorrect, certainly.

• 5:47Neil deGrasse Tyson?

  Things can only get worse globally in the universe.

• 5:50Brian Cox?

  Exactly. So, and then, so, so yeah, so I had a two.

• 5:55Neil deGrasse Tyson?

  And that song, what helped it, if I remember correctly, some political candidate adopted it as their theme song.

• 6:02Brian Cox?

  Tony Blair, it was a very, yeah, it was Tony Blair in nineteen ninety seven.

• 6:06Neil deGrasse Tyson?

  It became his, associated with his election.

• 6:09Brian Cox?

  Yeah. And came back actually into fashion because we'd just had a, a change of administration in the UK. And that song came up again. And it came up and it got quite popular again. So I did Glastonbury this year with the band.

• 6:23Neil deGrasse Tyson?

  Wait, that's that huge place.

• 6:25Brian Cox?

  Yeah, the big festival, yeah.

• 6:26Neil deGrasse Tyson?

  That's the, any huge scene.

• 6:30Neil deGrasse Tyson?

  Of musicians in the UK isn't that location.

• 6:33Brian Cox?

  Well, it's the world. I mean, it's probably the biggest festival in the world, I would imagine. I would guess. It's a huge festival.

• 6:38Neil deGrasse Tyson?

  So you and Brian May.

• 6:40Brian Cox?

  Those we are the two. He did it the other way around, though. He he so he he got extremely well, yeah, he got extremely famous and then finished his PhD.

• 6:51Neil deGrasse Tyson?

  In astrophysics.

• 6:52Brian Cox?

  Yeah.

• 6:52Neil deGrasse Tyson?

  Yeah, OK. Brian May, a lead guitarist of.

• 6:56Brian Cox?

  Queen.

• 6:56Neil deGrasse Tyson?

  Queen, yes.

• 6:57Brian Cox?

  Yeah.

• 6:58Neil deGrasse Tyson?

  Yeah. So let's pick up some of the physics. We are both here right now in Las Vegas. At a World Skeptics Conference.

• 7:08Brian Cox?

  Yeah.

• 7:08Neil deGrasse Tyson?

  Yeah, we we're both skeptics. I mean, any scientist is a skeptic. But the problem is, when the world does weird things, who's going to put them in check? Somebody's got to show up at the scene and say, no, that's not how that works. Or the laws of physics prevent that. Or you so you've you've had to do this in the UK, right? There's certain resonances between the United States and the UK about how people miss think things. So what was your baptism into this world?

• 7:41Brian Cox?

  Well, actually, I mean, I was only interested in doing research for a long time. So I as a postdoc and that in that part of my career, I didn't want to know about anything else other than doing research. And that's all I did. But it was, I can't remember when it was now, but there was one of those regular funding crises, as you'll know from here in the US, when when government support, in particular for research, dipped. And so I got involved in trying to fight that. And we realize, I mean, it's kind of obvious, I suppose, but we realized that one of the reasons, talking to government, that they had cut the research budget, was that they didn't think anyone cared. So they thought it was a simple thing to do.

• 8:26Neil deGrasse Tyson?

  Democracy.

• 8:26Brian Cox?

  You could just and so we we all as a community, we were reed. We we learned again, we've learned over the years, but we learned again that popular support, popular support for what we do is important. And and where does the support come from? It comes from understanding. And I could. There are many reasons, by the way, why. Talking to people who are not in science about what we are doing as scientists is important. One of them, of course, is just purely democratizing knowledge. It's we taxpayers fund at least in part what we do. And therefore they have a right to know. So there's that level. But on the other level, which I think you're suggesting as well.

• 9:09Brian Cox?

  And what science does, I think it's not it's not about knowing the facts. It's not about really, it's not about knowing the universe 13.8 billion years old, for example. Or it's 13.8 billion years since the big bang. We could talk about that later, actually. Does that mean it had a finite origin in time in the past? Anyway, but it's not.

• 9:28Neil deGrasse Tyson?

  Put a pin in that, we'll get back to that, okay?

• 9:30Brian Cox?

  It's not about knowing facts so much as understanding something about the process by which we acquire reliable knowledge about the world. And and science is the process by which we acquire reliable knowledge. And so I I think that I realized.

• 9:48Neil deGrasse Tyson?

  In that.

• 9:49Brian Cox?

  Well, it's, yeah, in the sense, I think in a sense that nature is there, whether any, any the job of the scientist is to find out how it works. And of course, as Richard Feynman and many others have famously said, it doesn't care who you are or what your opinion is, or how popular you are, or how many votes you got, or anything, how much money you've got. It just doesn't care. So in that sense, I think it is a unique pursuit because the the standard by which your opinion is judged is is external to us. It's nothing to do with humanity.

• 10:23Neil deGrasse Tyson?

  Nature is the ultimate judge, jury and executioner.

• 10:26Brian Cox?

  So so I think I became involved initially just on that very narrow idea that we wanted to make sure that people understood what we did and what the value of it is. And then that branch that that became bigger and bigger in my career. And and branched out into television and and live shows and all sorts of things. But it came from that, that's, I wasn't interested in communicating science. I was just interested in doing it for a very long time.

• 10:54Neil deGrasse Tyson?

  So you had a certain duty and responsibility to the world.

• 10:58Brian Cox?

  Well, I think we all do. I mean, I've realized since that I I think.

• 11:04Brian Cox?

  Actually Feynman again said it's a very brilliant essay that anyone can download from 1955, I think it is, called "The Value of Science", it's just four pages and it's there, it's on Caltech's archive, I think. And in there, he says that it is our duty as scientists, our duty, knowing the great value of, he calls it, he defines science as a satisfactory philosophy of ignorance, which is a beautiful, just merely satisfactory, it's a philosophy of ignorance, he started out from not knowing, and he said, and he said, "The great value of the satisfactory philosophy of ignorance, the great value of freedom of thought, to proclaim that freedom and to try to protect it for all coming generations", he essentially says at the

• 11:46Brian Cox?

  end. But I like the framing, it is our duty as scientists to do that, as well as do our job, which is to find things out about nature.

• 11:56Neil deGrasse Tyson?

  About the natural world. And I, in this conference, I am to bestow upon you the Richard Dawkins Award for Science and Reason.

• 12:06Brian Cox?

  Bestow.

• 12:07Neil deGrasse Tyson?

  Bestow, yes. The Richard Dawkins Award is something I won last year and I was called back in to bestow it upon you.

• 12:16Brian Cox?

  Passion, passion gets taught, it's a great honour.

• 12:19Neil deGrasse Tyson?

  It is a, it will be a delight for me, it takes place tonight.

• 12:23Brian Cox?

  Yeah.

• 12:23Neil deGrasse Tyson?

  I look forward to that. And just the idea that science and reason is something, maybe it's sad that it's something that needs to be rewarded, because if, it's one of these awards that if the world functioned just right, you wouldn't need it.

• 12:40Brian Cox?

  And also, you know, although I said, as Feynman has said, it's in a sense our duty as scientists, it is also true that not all scientists want to, want to do that or feel comfortable with it. As I said, I didn't want to do it initially. Now, I very much enjoy it and think it's very important. But, so, we don't need everybody to do it, but, but some people will. And that's, that's important.

• 13:21Speaker 02

  Hello, I'm Vinky Barok Allen and I support StarTalk on Patreon. This is StarTalk with Neill Grass Tyson.

• 13:40Neil deGrasse Tyson?

  So, let's talk physics. Take me to the frontier of particle physics today. What's going on at CERN now that the Higgs boson is discovered and the Nobel prizes were granted? What are they doing now?

• 13:55Brian Cox?

  Well, at CERN-

• 13:56Neil deGrasse Tyson?

  Do they just close shop and go home?

• 13:58Brian Cox?

  No, I mean, what particle physics is, because we're talking about quantum mechanics, basically, it's statistical in the sense that you collide, what we do there is collide protons together at high energy and we collide a lot of protons together at high energy.

• 14:13Neil deGrasse Tyson?

  Protons have a charge so that you can put them in a magnetic field and accelerate them-

• 14:18Brian Cox?

  Yeah.

• 14:19Neil deGrasse Tyson?

  -to very high speeds.

• 14:20Brian Cox?

  Yeah, so they go around, so the LHC in kilometers is 27 kilometers and that's the number-

• 14:25Neil deGrasse Tyson?

  In circumference.

• 14:26Brian Cox?

  Yes, that's about 16 miles or something like that.

• 14:28Neil deGrasse Tyson?

  Mm-hmm.

• 14:29Brian Cox?

  And, uh, and the, the protons go around that ring 11,000 times a second. That's how fast they go.

• 14:36Neil deGrasse Tyson?

  That's fast.

• 14:37Brian Cox?

  That's 99.9999999% the speed of light.

• 14:41Neil deGrasse Tyson?

  Okay, so you, you've granted them energy so that when you collide them, you break them apart. You're basically deconstructing nature-

• 14:52Brian Cox?

  You do.

• 14:52Neil deGrasse Tyson?

  -to see what residue comes out of it. When I think of doing that for anything else, it's gonna break, right? I don't take chairs and slam them together and still have chairs. I have a pile of-

• 15:06Neil deGrasse Tyson?

  Kindling, okay, so who ever thought it was a good idea to smash nature into itself?

• 15:14Brian Cox?

  Well, I suppose Ernest Rutherford initially, so we go back to Manchester, the turn of the 20th century, and Rutherford was using radioactive decay to essentially produce the particles. I mean, it's just the decay of atomic nuclei that naturally happens to produce energy particles, which he then fired into gold foil and bounced them off the foil. In doing that, he discovered the atomic nucleus. So one way to think about particle physics is that when you collide things together, what are you doing? You're really building a microscope. One way to think of it is that the higher the energy of the collision,

• 15:54Brian Cox?

  the faster these things are traveling, the smaller the object you can see. So we were talking about seeing for the first time in those experiments, the atomic nucleus. You move forward to the, well, ultimately through the 50s and 60s, and we have higher and higher energy collisions, you start seeing that the nucleus is made of protons and neutrons, and then you start seeing in the 50s and 60s that the protons and neutrons are made of smaller things called quarks, and so we discover those. We've not discovered anything smaller than that, by the way.

• 16:28Neil deGrasse Tyson?

  Is it because you don't have enough energy to bust up a quark?

• 16:31Brian Cox?

  Yes, well, or to resolve what's inside it, let's say, to build a microscope.

• 16:35Neil deGrasse Tyson?

  Because right now, the inventory of fundamental particles includes quarks.

• 16:41Brian Cox?

  Yeah.

• 16:41Neil deGrasse Tyson?

  So somebody saying that's fundamental, which sounds a little like the Greeks saying atoms are fundamental.

• 16:45Brian Cox?

  Oh, no, they won't be fundamental. You're absolutely right. But they look point-like from the point of view, from the energies that we can generate today. But that's one side of particle physics. So we've been exploring the structure of matter, which is historically, you know, it goes back to Rutherford, I suppose.

• 17:02Neil deGrasse Tyson?

  And again, you have confidence that when you break matter apart, you didn't break the matter. You're just deconstructing it.

• 17:11Brian Cox?

  Yeah, you're, it really, I think the way to think about it, when you think about what a collision is. So let's say you collide, as we did in my PhD, electrons and protons together. So you get an electron beam and a proton beam and you smash them into each other. What's actually happening? What's actually happening is one way that the collision can happen is that the electron can emit a photon, which is a particle of light. And the particle of light goes and it, and it, and it hits the phot- the proton. Now, the, the wavelength of that light, which is, which is telling you how small a thing you can see, is proportional to the energy of the thing. That's how hard we're smashing the things together. So the faster you smash them together, yeah, so the faster you smash it together, the higher the energy,

• 17:55Brian Cox?

  the smaller the wavelength, so the smaller the things that you can see. So, so that's a way of thinking about particle collisions. So it really is a microscope in that sense, that analogy works.

• 18:05Neil deGrasse Tyson?

  I'm just thinking, if our proton, I wouldn't want to be busted apart into quarks. That would not be a nice day for me.

• 18:11Brian Cox?

  In some ways, I suppose it's like having, and like having an X-ray, I suppose, isn't it? Oh, you're right, though, you hit them hard enough and they fall to bits, but that would be the same for you. So, but we would try not to hit you that hard.

• 18:24Neil deGrasse Tyson?

  Except the bits that I fell into, no one's considered them fundamental bits of Neil, right?

• 18:30Brian Cox?

  But the other way to think about particle physics, which is, I think, so you say the Higgs particle you mentioned. So that's not in the proton. You're not, you're not smashing the things together and finding a Higgs particle buried in there somewhere. The other side is really, so you think of Einstein's famous equation, E equals mc squared. So energy and mass are interchangeable, let's put it like that. So it also says that if we have loads of energy in these collisions, then we can make new particles that are extremely massive, much more massive.

• 19:00Neil deGrasse Tyson?

  That would come spontaneously out of the available energy that would otherwise be doing nothing.

• 19:04Brian Cox?

  Yeah, so, so we have, when you collide protons together, these energies, you have plenty of energy there to make a Higgs particle, for example, or a top quark, which is a very heavy particle as well, far more massive than the protons. So, so that's, I suppose, the way to think about trying to manufacture Higgs particles so you can observe them. You need enough energy to make them.

• 19:28Neil deGrasse Tyson?

  So you're not just busting them apart, you're creating an opportunity. To view more massive particles than would otherwise be available to you.

• 19:36Brian Cox?

  Yeah, and the other thing to say, so to get a complete picture is these very massive things like Higgs particles, they have a very short lifetime. So you make them and they decay away into lighter particles, very, very fast. So you don't see the Higgs particle. What you see is the debris from the decay of the Higgs particle. And the challenge of particle physics is to detect all those bits that came off, basically. And by the way, you also have the bits of the protons that all got smashed up as well. So it's a big mess. And we have more than...

• 20:09Neil deGrasse Tyson?

  I've seen these dark these...

• 20:11Brian Cox?

  It's very hard because you don't only have one proton collision per... We send the particles around in little bunches, basically. So you can get 10, 20, 30 collisions at the same time. Only one of them, on a very good day, will be an interesting one. And then so you've got to sift through all this, which is the difficulty, or the professional challenge, let's say, of particle physics.

• 20:34Neil deGrasse Tyson?

  With that reasoning, there's always some next energy level that you haven't visited.

• 20:39Brian Cox?

  Yes.

• 20:40Neil deGrasse Tyson?

  Where more and interesting physics can reveal itself.

• 20:42Brian Cox?

  And this is where it gets challenging at the moment. Because so the so-called standard model Higgs particle, and I should just say for a minute, that thing, the existence of this thing was predicted in the 1960s by Peter Higgs and others. And it was a suggestion, a theory, a guess, let's say, at the time, mathematically motivated, almost purely, by the way, mathematically motivated, of how things get mass in the universe at the most fundamental level. To have the quarks and these very heavy things called the W and Z bosons, that how those things got mass. And so it was a mathematical construct. It

• 21:25Brian Cox?

  predicted that there should be, in the simplest case, one, this thing, the Higgs boson. But there could be more complicated versions. And so we knew that if we collided protons together at the energies that we generate at the Large Hadron Collider, then we would either discover the Higgs boson... And prove this theory to be correct. Or we knew that if it wasn't there, we would see something else. So we had a very clear idea from experiment and theory that we were going to discover something with that machine. And you don't know what it is. It turned out it was the simplest thing. It was this thing that Peter Higgs had had dreamt of all those years ago, which is astonishing.

• 22:10Brian Cox?

  By the way, 50 years after the prediction. And there's a great essay that you might know by Eugene Wigner called The Unreasonable Effectiveness of Mathematics.

• 22:18Neil deGrasse Tyson?

  Of Mathematics, yeah.

• 22:19Brian Cox?

  Physical Sciences.

• 22:20Neil deGrasse Tyson?

  Yeah.

• 22:20Brian Cox?

  I think that's the one of the best examples. It's an astonishing achievement that we got it right. And so, so we discover the Higgs boson.

• 22:28Neil deGrasse Tyson?

  To put precision on that, that Wigner's

• 22:32Brian Cox?

  Yeah.

• 22:32Neil deGrasse Tyson?

  The point in that paper. It's not that math in a vacuum, no pun intended, makes discoveries. It's the mathematical representation of a physical idea.

• 22:44Brian Cox?

  Yeah.

• 22:45Neil deGrasse Tyson?

  And then you pursue the math. And it applies to the universe, but only if the physical idea is has captured reality in some fundamental way.

• 22:58Brian Cox?

  Although it was, I think, the, it was a very, a very mathematical framework, which became the standard model of particle physics, based on ideas of symmetries and all sorts of beautiful ideas, which really do have mathematical foundations. There's an aesthetic sense, I think, built into that model.

• 23:18Neil deGrasse Tyson?

  And that would be the pure mathematical. See, I'm, you know, my people in astrophysics, we have enough embarrassing historical examples of chasing, you know, elegance and beauty.

• 23:31Brian Cox?

  Kepler.

• 23:32Neil deGrasse Tyson?

  Kepler, I'm saying, look at Kepler.

• 23:34Brian Cox?

  But I, I think the genius of Kepler is he had these platonic solids and these ideas.

• 23:38Neil deGrasse Tyson?

  Right, he's got the pyramid and the cube and the this and.

• 23:41Brian Cox?

  But then he rejected it based on data.

• 23:44Neil deGrasse Tyson?

  Yes.

• 23:44Brian Cox?

  In 16.

• 23:46Neil deGrasse Tyson?

  His first thought was the universe is beautiful and divine and perfect. And these solids are perfect. Planets are in the universe, so it must be a connection. He spent 10 years looking at it.

• 23:58Brian Cox?

  Yeah, but then.

• 23:59Neil deGrasse Tyson?

  But then he rejected it.

• 24:00Brian Cox?

  And then the laws of planetary motion, which which are indicative of a very beautiful thing, which is Newton's law of gravitation, the inverse square law.

• 24:08Neil deGrasse Tyson?

  Yeah.

• 24:08Brian Cox?

  And so there is a there's a beauty underlying it.

• 24:10Neil deGrasse Tyson?

  But only after he had to scrap this other beauty that he had presumed it would be. That's why we step lightly when someone says, I have this beautiful idea. Yeah, OK, let's hear it.

• 24:21Brian Cox?

  But but it is true that I I think it's one of the great mysteries that there is. Historically, Einstein's theory of general relativity is another example, where where a quest for simplicity and beauty and elegance, which are judgments, and the human judgment, has led to very, very precise models of the way that nature works.

• 24:43Neil deGrasse Tyson?

  Given that CERN, which has the Large Hadron Collider, LHC, discovered the Higgs boson. If you're going to discover more particles, presumably you have to keep sort of upgrading the system as the LHC was compared to what was there before, so that you can ever with ever greater force bust into the particles and see what's lurking.

• 25:07Brian Cox?

  So we can't increase the energy of the LHC very easily. So or even easily, or we can't really.

• 25:15Neil deGrasse Tyson?

  At all.

• 25:15Brian Cox?

  So that would be a major change to the machine. But what we can do and are doing is so called high luminosity upgrades, which means you collide more protons together. And the thing about.

• 25:30Neil deGrasse Tyson?

  So then you win on the statistics of the event.

• 25:32Brian Cox?

  Because particle physics is a quantum mechanics. And so things happen statistically. So so it's, you know, one in, I don't know the numbers I've made, one in 10 billion collisions, you'll produce something interesting. A Higgs, it's less than that. But so so when when giving yourself more collisions gives you more chance to discover new particles, and it gives you more particles like Higgs bosons to explore.

• 25:59Neil deGrasse Tyson?

  If you get a Higgs particle. After however many collisions, and that's kind of rare. If you have more collisions, you'll get more Higgs.

• 26:08Brian Cox?

  Yeah.

• 26:08Neil deGrasse Tyson?

  To improve your statistics on what the hell the Higgs is.

• 26:11Brian Cox?

  Yeah, because we want to know.

• 26:12Neil deGrasse Tyson?

  But then, there could be a reaction that's even rarer to manifest than the Higgs.

• 26:18Brian Cox?

  Yes.

• 26:19Neil deGrasse Tyson?

  And if your sample wasn't large enough, you would just never go there.

• 26:21Brian Cox?

  Yes, you wouldn't see it. If you just made one thing, one particle, you know, one, whatever it is, Higgs prime, whatever. If you made one of those, then you wouldn't see it if you made one of them.

• 26:34Neil deGrasse Tyson?

  Sounds like superhero nemesis. I'm Higgs prime. You know, I've come to destroy.

• 26:39Brian Cox?

  By the way, and we do look for those things, the Z prime, the Z boson, we look for the Z prime, because they can be signatures of extra dimensions in the universe, by the way, so we look for this stuff. But the point is that i- if something is very, very rare, then you won't really see it. If you just make one or two of them, you need to make hundreds or thousands or whatever it is to see them.

• 26:58Neil deGrasse Tyson?

  Yeah, it's like, how many people have to live in a city before you stumble on someone who's seven feet tall?

• 27:03Brian Cox?

  Yeah. That's a statistic.

• 27:04Neil deGrasse Tyson?

  Statistically, you need, possibly millions.

• 27:09Brian Cox?

  Yeah. So the upgrades are, the upgrades that we can do, and you have to upgrade the detectors, the cameras that we use, as well as the machine.

• 27:16Neil deGrasse Tyson?

  Okay, so you kept the same hole in the ground?

• 27:18Brian Cox?

  Yeah, because we don't want to dig another one of those, or change all the magnets around, which are very expensive.

• 27:23Neil deGrasse Tyson?

  Does that hole go through more than one country, or is it all contained in Switzerland?

• 27:26Brian Cox?

  France and Switzerland.

• 27:27Neil deGrasse Tyson?

  Wow, okay.

• 27:28Brian Cox?

  Yeah, most of it's in France, actually.

• 27:29Neil deGrasse Tyson?

  Oh, didn't know that.

• 27:30Brian Cox?

  Only a little bit of it's in Switzerland.

• 27:32Neil deGrasse Tyson?

  Okay.

• 27:33Brian Cox?

  So that's one thing. And the other thing is, this Higgs that we've discovered, the question still remains, is it the simplest one, the standard model Higgs? Or is it something more complicated? How does it behave? So the analogy in planetary science would be, you know, we discovered a moon, and so you go, great. Then you would like to know about the moon. You don't want to just say, we've discovered this moon, it's a dot. That's fine. As you said, they're in.

• 28:01Neil deGrasse Tyson?

  Want to characterize it in whatever way you can.

• 28:03Brian Cox?

  For that, you need a lot of them to observe. So it's exciting, but, and it's challenging, because I think for the first time, it's probably true to say in particle physics. We don't know if there's anything else just around the corner, which is bad. You know, but it's also, I suppose it's just science. I mean, ultimately, it's neither bad nor good. It's the way nature is.

• 28:29Neil deGrasse Tyson?

  That's what triggers whatever next round of physics is complete.

• 28:33Brian Cox?

  Yeah.

• 28:34Neil deGrasse Tyson?

  You know, you get people, you get those people that show up and say, there's nothing left in physics to discover.

• 28:39Brian Cox?

  Well, they'd be

• 28:40Neil deGrasse Tyson?

  They show up every few decades.

• 28:42Brian Cox?

  So utterly wrong.

• 28:43Neil deGrasse Tyson?

  Yeah.

• 28:43Brian Cox?

  They're not even worth consuming. I mean, you know, there's tremendous progress, Bima. It's such an exciting time in fundamental physics at the moment. The particle physics, not only particle physics, but we said gravitational astronomy, the exploration of the force of gravity, black holes, quantum information, which is related to quantum computing and all sorts of, all that stuff is to me utterly fascinating. There's some really interesting, I read some stuff the other day, which I don't fully understand, actually, some of the progress in string theory. It's interesting because just as an aside, it's linking, it seems to me, it's linking one of the great mysteries,

• 29:27Brian Cox?

  which is the so-called cosmological constant. So the fact that we observed that the universe is accelerating in its expansion.

• 29:33Neil deGrasse Tyson?

  And Nobel Prize has been given for the observation, not for the understanding.

• 29:37Brian Cox?

  Yeah, a friend of mine, who by the way, didn't believe his, he didn't believe it when he saw it because it wasn't in the air, this idea. He was looking at light from supernova.

• 29:47Neil deGrasse Tyson?

  Right, right. I'm on, I'm on a paper with Brian Schmidt.

• 29:51Brian Cox?

  Yeah.

• 29:51Neil deGrasse Tyson?

  I'm like very minor author. You have to scroll down and then like my name is

• 29:56Brian Cox?

  In the supernova, yeah.

• 29:58Neil deGrasse Tyson?

  But it was, it was, it was analysis of high redshift supernovae.

• 30:01Brian Cox?

  Yeah.

• 30:02Neil deGrasse Tyson?

  And I totally enjoyed that work, but he obviously went on and made an entire sort of

• 30:07Brian Cox?

  Yeah.

• 30:07Neil deGrasse Tyson?

  branch of his career on it.

• 30:09Brian Cox?

  So there's this remarkable idea that, which comes from that, which is, which is in Einstein's theory, this idea that you can, you can have a kind of energy in the universe, let's say, or a thing, whatever it is, because we don't know what it is, but something that makes the universe, that the rate, the space stretches increase, which is, so that that's there and it's observed. It's one of the great mysteries because it's, I think it's the smallest number in all of physics by

• 30:39Brian Cox?

  What is it? It's something like a 10 to the power minus 122 or something inappropriate units, right? Which is absolutely ridiculously. So it's a tiny, tiny, tiny, tiny thing that's causing this rate of expansion. But it's not zero. And so the question becomes, why is it tiny?

• 30:59Neil deGrasse Tyson?

  Why is it tiny and not zero?

• 31:00Brian Cox?

  Yeah, yeah. And so because if it were even slightly bigger, we wouldn't be here. So the universe would have been blown apart. So it seems very unusual. But I saw the other week, the other day, actually, that there's some research that's linking that in the framework of a string theory, or M theory, to dark matter. So there's a kind of an idea that if you fix that, you get a prediction out that there should be dark matter. But it turns out it's to do with extra dimensions and gravitons in extra dimensions and things. So it's quite, but it's quite interesting. So I think there are some very interesting areas of string theory where progress is being made quite remarkably.

• 31:44Neil deGrasse Tyson?

  Do string theorists need a fuller or better inventory of particles? So for example, are we still looking for a graviton? Are we still looking for, you know, every, you shake a stick and there's a physicist proposing a hypothetical particle to explain dark matter, to explain whatever.

• 32:01Brian Cox?

  Wouldn't it be cool if the dark matter were related to gravitons, which is, this is not my field, I only heard of it the other day, but it sounded interesting. But it just shows you that we, so to go back to LHC, we have the Higgs particle, as you said. We had expected, I would say most particle physicists expected there would be other particles discovered. There's a particular theory.

• 32:28Neil deGrasse Tyson?

  In that same experiment?

• 32:29Brian Cox?

  Yeah, at LHC. So there's a particular theory, which motivated by string theory a long time ago, called supersymmetry, which is a property of the universe.

• 32:39Neil deGrasse Tyson?

  It's been around for many decades.

• 32:41Brian Cox?

  Yeah, and it came initially from.

• 32:44Brian Cox?

  Either from string theory or from some other and got incorporated in, I can't remember historically which way it came. But it's, um, but it essentially predicts that there are double the number of particles that we see, fundamental particles of this energy. So, so we, and they would have been great candidates for dark matter, by the way, which is an astrophysical discovery. So we should say, I suppose, the one, the one sentence description of dark matter is that we see the, the universe, there's far much more matter in the universe than we can see.

• 33:15Neil deGrasse Tyson?

  See, I would put it differently.

• 33:16Brian Cox?

  Yeah.

• 33:17Neil deGrasse Tyson?

  I would say there's far, it's not dark matter, it's dark gravity.

• 33:22Brian Cox?

  Well.

• 33:23Neil deGrasse Tyson?

  You say matter, we don't know what, we don't know what it is.

• 33:25Brian Cox?

  Well, it's true. So you see it through its gravitational.

• 33:27Neil deGrasse Tyson?

  So it's dark gravity.

• 33:29Brian Cox?

  Yeah.

• 33:30Neil deGrasse Tyson?

  We don't, see, otherwise you get newspaper headlines, say, oh, uh, we must abandon our ideas of dark matter. Well, if it's not matter, it's still there. Okay. It's misnamed.

• 33:42Brian Cox?

  Yes, I see what you mean. I mean, I, I, that's a cool newspaper, by the way, that would have a headline like that.

• 33:47Neil deGrasse Tyson?

  That it goes there at all.

• 33:48Brian Cox?

  It's usually about a football player and so I'm on board with that newspaper.

• 33:52Neil deGrasse Tyson?

  Yeah, I'm saying, if we don't know what it is, we had no business calling it matter at all.

• 33:57Brian Cox?

  So the thing to say, though, is that.

• 33:58Neil deGrasse Tyson?

  Dark gravity.

• 33:59Brian Cox?

  The best.

• 34:00Neil deGrasse Tyson?

  Which sounds cool.

• 34:01Brian Cox?

  So you build model, you build models and it is true that the best model that fits all the data, which is not just the way that gravity, that galaxies rotate and collide and the way that gravity's, that galaxies kind of lens, light and all those things, but also the cosmic microwave background radiation, which is the oldest light in the universe and how that worked and how the ripples, the sound waves went through the early universe and all that. You put it all together and it fits if you have a light, a light-ish particle that does not interact with light, but interact weakly.

• 34:35Neil deGrasse Tyson?

  So this would be another category of particle in the particle soup.

• 34:39Brian Cox?

  Yeah.

• 34:40Neil deGrasse Tyson?

  That has gravity, but doesn't interact electromagnetically, only very weakly.

• 34:45Brian Cox?

  So you can't see it.

• 34:46Neil deGrasse Tyson?

  And so just, it's, all right.

• 34:47Brian Cox?

  Yeah. So that's a model, though, you're right. So that's a model, which is kind of, I would say, the baseline model.

• 34:53Neil deGrasse Tyson?

  Yeah, it's the assumption, people assume that. And I don't have a problem with it, but if anything happens to that model. It gets shown it can't be true. People say, "Oh, then there is no dark matter." "No, there's still dark. It is a measurement in the universe." "We've just misnamed it."

• 35:09Brian Cox?

  Yeah, I agree. The measurement is just galaxies spin around too fast.

• 35:13Neil deGrasse Tyson?

  Too fast.

• 35:14Brian Cox?

  Or the way they collide, and so on. There's quite a lot of independent measurements of this thing.

• 35:19Neil deGrasse Tyson?

  So tell me about a graviton. I mean, is that a real particle?

• 35:22Brian Cox?

  I think most physicists would say that quantum mechanics

• 35:25Neil deGrasse Tyson?

  Requires it.

• 35:26Brian Cox?

  Is the base, is the base theory. I think the reason I'm careful is because there are some people who would say general relativity is a thing, spacetime is a real thing and all that. But I think generally, most people would say quantum mechanics is underlying it. And that if you have an interaction...

• 35:43Neil deGrasse Tyson?

  In other words, quantum physics is foundational

• 35:45Brian Cox?

  Yeah.

• 35:46Neil deGrasse Tyson?

  to the universe in ways that even general relativity would not be.

• 35:49Brian Cox?

  Yeah, so we could talk about this later, but the idea that space and time, or spacetime, emerge from a quantum theory is very fashionable at the moment. Partly because of the study of black holes, so we could talk about that.

• 36:02Neil deGrasse Tyson?

  Uh huh.

• 36:03Brian Cox?

  So, so given that, then you, so I should say, just for people who are watching and listening, that so how would we picture the electromagnetic force in particle physics? So we know that if you put light charges together, they repel and so on. So what's happening there? Or if you bring magnets together, right, they repel each other. Everybody knows the North Pole together and they repel. So what's happening in particle physics terms? You picture that as the exchange of a photon. It's a particle of light, goes from one particle to the other, and essentially carries the force. So that's what our particle physicists would picture, that force, all forces.

• 36:44Neil deGrasse Tyson?

  Have we successfully applied that to gravity?

• 36:47Brian Cox?

  No, so that's the point. So, but the assumption...

• 36:51Neil deGrasse Tyson?

  Give me a more resonant "no."

• 36:53Brian Cox?

  The very, the very strong, I suppose, I'm trying to find the right word for it. I think that's why I said conviction. It's almost, I don't know of any physicist who would disagree with this.

• 37:03Neil deGrasse Tyson?

  Because if you can't fold it into the quantum world...

• 37:08Neil deGrasse Tyson?

  You don't really have a right to start looking for a graviton. Because you're gonna say the graviton is the mediating particle.

• 37:14Brian Cox?

  Yes, it's the photon.

• 37:15Neil deGrasse Tyson?

  In the way the photon is the mediating particle.

• 37:17Brian Cox?

  So, and that's, I don't think you'd find anyone who would disagree with that statement.

• 37:22Neil deGrasse Tyson?

  Okay.

• 37:23Brian Cox?

  Although, I don't think you would. Although, it is true to say that because gravity is so weak, so this is the other thing to say. It is tremendously weak compared to the other three forces of nature, of which electromagnetism is one.

• 37:38Neil deGrasse Tyson?

  I tell people, you've surely done this in class. They say, how weak is gravity? Well, I can pick something up off the floor against the wishes of Earth.

• 37:45Brian Cox?

  Exactly, yeah.

• 37:46Neil deGrasse Tyson?

  Yeah, the whole Earth is pulling on this ball and I can just pick it up off and kick it into the goal.

• 37:53Brian Cox?

  And you're using electromagnetism, that's what's happening. So your muscles and all that things, this is all electromagnetic force, which completely destroys, as you said, the gravitational force. But gravity is only additive, so it only adds up in the universe. So it is the dominant force on cosmic distance scales. That's the point about gravity.

• 38:12Neil deGrasse Tyson?

  Here's a calculation I haven't verified, but it sounded legit. Very verifiable, I just never, I was too lazy. That if you take like the space shuttle in its glory days and you take one, remove the electrons from one cubic centimeter in the nose of the main tank and take all those electrons and put it at the base of the launch pad, it could, would not be able to launch. The attraction between the electrons at the base of the launch pad

• 38:41Brian Cox?

  See.

• 38:42Neil deGrasse Tyson?

  and the net positive charge at the top

• 38:43Brian Cox?

  Right, yeah.

• 38:44Neil deGrasse Tyson?

  is enough to prevent it from launching.

• 38:46Brian Cox?

  Yeah, that's a cool idea.

• 38:47Neil deGrasse Tyson?

  Yeah, that's cool.

• 38:48Brian Cox?

  I could see that that would be.

• 38:49Neil deGrasse Tyson?

  Yeah, yeah, actually it would

• 38:51Brian Cox?

  Yeah.

• 38:52Neil deGrasse Tyson?

  Borrow a whole.

• 38:54Brian Cox?

  It'd probably, yeah.

• 38:55Neil deGrasse Tyson?

  It's not a realistic experiment, but. To get some sense of the forces involved.

• 39:00Brian Cox?

  Yeah, that's a really nice.

• 39:02Neil deGrasse Tyson?

  Okay, so gravity is weak. That somehow bails you out of this problem?

• 39:05Brian Cox?

  Well, it just means that you can't, we don't have experimental access to them.

• 39:09Neil deGrasse Tyson?

  Okay.

• 39:09Brian Cox?

  Because it's so weak.

• 39:11Neil deGrasse Tyson?

  I.

• 39:11Brian Cox?

  So.

• 39:12Neil deGrasse Tyson?

  Whereas we do have experimental access to photons.

• 39:14Brian Cox?

  Yeah, unless you could potentially have access if there were extra dimensions in the universe that are configured in the right way.

• 39:24Neil deGrasse Tyson?

  Physicists are always throwing in extra dimensions.

• 39:26Brian Cox?

  Well.

• 39:26Neil deGrasse Tyson?

  Whenever you need it, you know.

• 39:28Brian Cox?

  It is interesting, though, that that string theory works in 10 dimensions and only 10 dimensions mathematically. So that's an interesting observation, right? So.

• 39:40Neil deGrasse Tyson?

  I don't, I don't, I don't have the background to be an authentic string theory skeptic, but I know physicists who are. And so.

• 39:49Brian Cox?

  I don't, yeah, I think there are, I mean, it depends, I think it depends what you mean by string theory. I mean, there was, if you go back, you know, a few decades, you talk to Brian Greene, for example, and when he started working in this area, he was.

• 40:01Neil deGrasse Tyson?

  He's a friend of StarTalk.

• 40:02Brian Cox?

  Yeah, yeah. He would have, his great book, The Elegant Universe, is a beautiful description of string theory. And so I think the idea initially with the hope was that you'd have a theory and you could write it down. It's a theory of everything and it will predict the universe as we see it.

• 40:16Neil deGrasse Tyson?

  And then you go home and then.

• 40:17Brian Cox?

  Yeah, and I think that's gone as an idea. But the, the, the, the basic idea of these, I mean, why is it called string theory? It's because particles are not point like, these strings are like little strings, little loops and, and that, that idea, I think, is still at the foundation of most modern theoretical physics in this area. But it's got much more complicated and it's been much harder. I think the initial idea that you could just predict everything from one number maybe has gone away.

• 40:49Neil deGrasse Tyson?

  One simple equation on one line.

• 40:51Brian Cox?

  But there is tremendous progress being made in, in string theory. So it's, it's, it's not gone away. It's just become more complicated, I would say.

• 40:59Neil deGrasse Tyson?

  Well, thanks for catching me up on this. At this conference, you're giving a talk on black holes?

• 41:04Brian Cox?

  Yeah.

• 41:05Neil deGrasse Tyson?

  And there was some recent announcement, the biggest jet from a black hole ever discovered ever.

• 41:09Brian Cox?

  Yeah.

• 41:10Neil deGrasse Tyson?

  Ever. I, I, when I was asked about it by the press, I simply said, there's always a biggest jet in the universe. And so now this one. Is that?

• 41:22Brian Cox?

  It's the A380.

• 41:23Neil deGrasse Tyson?

  Okay.

• 41:24Brian Cox?

  Airbus A380, it's a fantastic aircraft.

• 41:26Neil deGrasse Tyson?

  Did I undersell the significance of this huge jet? So what if it's the biggest one unless there's some interesting physics that's coming out of it?

• 41:38Brian Cox?

  The area that I have, I share a PhD student who's working in the area is more theoretical. It's about quantum information, the way that information behaves inside and outside a black hole. What happens to things that fall in. But in terms of the astrophysical work, if you go back, you know, not long ago, we didn't really have any observation of how things behave in the vicinity of black holes. And so I would put it in that box. We've got several observations now. We've got the radio telescope observations from the Event Horizon collaboration that have shown us how the magnetic fields work, for example, around the black hole in the Milky Way. We've got these jets which are giving you access to the magnetic structure presumably in the way that they spin.

• 42:21Neil deGrasse Tyson?

  Thank you for putting it in that context. Now I can understand. It broadens the astrophysical dataset.

• 42:26Brian Cox?

  Yeah.

• 42:27Neil deGrasse Tyson?

  On which we can sharpen our hypotheses for what's going on.

• 42:30Brian Cox?

  Yeah, because they're hard things to observe.

• 42:32Neil deGrasse Tyson?

  Yeah.

• 42:33Brian Cox?

  And of course, you can't observe the interior because it's inside this thing called the Event Horizon. But what you can do, and we are doing, is observe the way that material behaves in the vicinity of them.

• 42:42Neil deGrasse Tyson?

  Mm-hmm.

• 42:43Brian Cox?

  Or the other remarkable thing we've been able to do in the last few years is watch them collide and see how the ripples in the fabric of the universe come out and we can detect those ripples. So all these things are allowing us to probe these objects. And it's worth remembering that they were present, they were described. Non-spinning ones were described fully by the work that Carl Swartshul did in 1916. So months after Einstein had published the theory of general relativity. He didn't know it at the time, but the mathematical description he found... Which describes how space and time are distorted in the presence of a star,

• 43:26Brian Cox?

  a non-spinning star, is kind of important. And those, those fully describe a black hole that isn't spinning.

• 43:32Neil deGrasse Tyson?

  If I remember correctly, he would die in the First World War. I don't think he made it out of the war.

• 43:37Brian Cox?

  No, he died in 1916, so shortly after. Not, not in action.

• 43:42Neil deGrasse Tyson?

  Oh, it was not in action, okay.

• 43:43Brian Cox?

  I think he died from diseases. He was on the Russian front.

• 43:48Neil deGrasse Tyson?

  Okay.

• 43:48Brian Cox?

  There was an, yeah.

• 43:49Neil deGrasse Tyson?

  It could be war-related, but not from an injury.

• 43:51Brian Cox?

  Yeah, I think it was, you would argue, war-related.

• 43:53Neil deGrasse Tyson?

  Yeah, so we've got, you know, more than a century of mathematical foundation for this.

• 43:58Brian Cox?

  And then you go forward to six.

• 44:00Neil deGrasse Tyson?

  With no data, no data.

• 44:02Brian Cox?

  No, and then, then, so it, it takes another 50 years, by the way, for someone to work out what it looks like for a spinning one, which is Roy Kerr, so famous Kerr solution. But those two solutions are there, they're in Einstein's theory in some, in a sense. And they describe the black hole. But observing them is something that we haven't been able to do till recently.

• 44:25Neil deGrasse Tyson?

  And multi-wavelengths as well.

• 44:27Brian Cox?

  Yeah, so now we have radio observations, the gravitational wave observations.

• 44:32Neil deGrasse Tyson?

  I'll be a little kinder to that.

• 44:34Brian Cox?

  Well, because it's the way, the thing is, as you said right at the start, science is about, yes, having ideas, building theories and so on. But it's, it's really fundamentally about testing those theories. And so we can talk about these theoretical objects, black holes, but really, and they are rich theoretically, but ultimately you've got to make observations. And that's where these jets and seeing how material behaves gives you access to the magnetic fields and how the thing's spinning and what it's doing. But that's important.

• 45:29Neil deGrasse Tyson?

  Let's talk about your work with the public. You said earlier, you share this commitment that Feynman declared duty to bring science to the public. You not only talk the talk, you walk the walk and you have spillage everywhere. You know, you've given tours, public tours in Australia, across Europe. And if I remember correctly, you're coming back to the United States next spring to give a tour across the country?

• 46:01Brian Cox?

  Yeah, yeah, it's a tour that's been going on for quite a long time. It wasn't meant to really, but we've ended up playing to over 400,000 people across the world with this tour.

• 46:12Neil deGrasse Tyson?

  Wait, wait, wait, you're not a musician. You say playing.

• 46:14Brian Cox?

  Playing.

• 46:15Neil deGrasse Tyson?

  Get your vocabulary straight.

• 46:16Brian Cox?

  I'm looking, I'm rock and roll, basically. I always have been that. So when we told you.

• 46:21Neil deGrasse Tyson?

  Playing to 400,000.

• 46:22Brian Cox?

  We have five trucks and two tour buses. It's brilliant. So I'm reliving my life as a.

• 46:27Neil deGrasse Tyson?

  So did I see a version of that when you came to the city?

• 46:29Brian Cox?

  Yeah, it was very early on, just after, it was just.

• 46:32Neil deGrasse Tyson?

  Yeah, you have these screens that interlock.

• 46:33Brian Cox?

  Yeah.

• 46:34Neil deGrasse Tyson?

  And then the whole stage is.

• 46:37Brian Cox?

  Yeah, and that was a very early iteration of this. And so it's changed a lot. Before I laid it to rest, this tour, and develop another one, I wanted to bring it back here in the form that it is now, which is so radically different from what it was three years ago.

• 46:51Neil deGrasse Tyson?

  And it's you celebrating the universe with and for the.

• 46:54Brian Cox?

  It is.

• 46:55Neil deGrasse Tyson?

  The public.

• 46:56Brian Cox?

  It also morphed into, there's a version that I do with the symphony orchestra, which is great fun. So I did it at Sydney Opera House, actually, initially, last year. And it's a big orchestra because it's 90-piece symphony orchestra because of the music that I chose. And so the. The reason, by the way, as a slight digression, it's part of this tour. The classical music is a big part of the tour. So it starts with Sibelius's Fifth Symphony, the third movement. And that was because a conductor friend of mine called Daniel Harding, I said to him, what should Stanley Kubrick have used in 2001 as a joke? Like, what should he have used? He immediately said Sibelius Fifth Symphony. And it is, it was written in 1915, same year that General Relativity was published.

• 47:41Brian Cox?

  But it's the basis of almost every science fiction theme you've ever heard. I go back to that. It's beautiful. And so the idea, which I've always strongly believed, but it came to my mind as I was doing this tour, is that what, if we're talking about deeper philosophical questions, which are raised by cosmology, I say right at the start, what does it mean to live a finite, fragile life in an infinite, eternal universe? Right, is it? And I say, of course, I don't know the answer to that. Is that uplift people or depress them? Well, but it's that, as you know, the moment you contemplate the scale of the universe. And I should say, we don't know whether it's infinite. We don't know whether it's eternal, right? But it could well be infinite and eternal. For all purposes, it kind of is, right? On a human scale, anyway.

• 48:26Brian Cox?

  Relative to a human scale, yeah. So, so the immediately when you contemplate the size and scale of the universe, you ask questions about our place and live quite vividly. What does it mean to live these little finite, fragile lives? And so I think I try to approach those questions and you realize, or I realize that there are other lights you can shine on that problem. And science is a necessary bright and vivid light that casts a very well delineated shadow, which is giving us some, obviously it's the framework within which we operate. But there are other lights. So you realize that Mahler, for example, so we use Mahler in the classical concerts. Mahler thought a lot about what it means to live a finite, fragile life.

• 49:09Brian Cox?

  And he gave a very eloquent answer, many eloquent answers in his symphonies. And he was once asked, by the way, what are you trying to say? What's this answer? And he said, well, if I could say it, I wouldn't have written the music. Good answer. So you have this music. So the music. So there's composers that I chose and that they are in the tour that we're going to do this coming year, next April.

• 49:34Neil deGrasse Tyson?

  Twenty twenty five.

• 49:34Brian Cox?

  Twenty twenty five. They're in there as music. The composers were chosen because they explored this question and gave very eloquent answers. So it adds to, I think, the more philosophical exploration of the questions that are raised by the science.

• 49:51Neil deGrasse Tyson?

  What's the name of the tour?

• 49:52Brian Cox?

  Called Horizons.

• 49:53Neil deGrasse Tyson?

  Horizons. That's easy enough to remember. Okay, very cool.

• 49:57Brian Cox?

  But there's a lot of black holes in it as well, I should say. So it's an exploration of the ideas that I find interesting.

• 50:03Neil deGrasse Tyson?

  Black holes are a horizon of its own.

• 50:04Brian Cox?

  They have horizons, yes. But also life in the universe, the origin, evolution of life, speculations on, we could talk about it, speculations on how many civilizations there might be as a guess.

• 50:15Neil deGrasse Tyson?

  Well, this thing about life in the universe, you've done many, many TV series and most recently one on the solar system.

• 50:24Brian Cox?

  Yeah.

• 50:24Neil deGrasse Tyson?

  Where the search for life is a main theme.

• 50:28Brian Cox?

  Well, yeah, we just saw, as we speak, last week, the Europa Clipper spacecraft was launched.

• 50:33Neil deGrasse Tyson?

  Yes.

• 50:33Brian Cox?

  On the way to Europa.

• 50:34Neil deGrasse Tyson?

  We have an entire show devoted just to that. We visited the Jet Propulsion Labs and felt the excitement of everyone there.

• 50:41Brian Cox?

  It's great, isn't it? It's the first spacecraft I've seen, major spacecraft, being built. So I saw the Clipper. And the thing is, the scale of that thing, it's the largest spacecraft, isn't it, that's ever been sent into the atmosphere?

• 50:53Neil deGrasse Tyson?

  Well, if you add that...

• 50:54Brian Cox?

  Or the most massive, I think.

• 50:56Neil deGrasse Tyson?

  Here's the... It may be, but there's another important fact. Solar panels have gotten more efficient. In the day, back if you were going to explore beyond the asteroid belt, you couldn't use solar panels. The intensity of the sun wasn't high enough. This one has a very deployable, large solar panel. It'll help it along without having to rely entirely on the nuclear decay of plutonium.

• 51:20Brian Cox?

  Yeah. So it's a huge spacecraft.

• 51:22Neil deGrasse Tyson?

  Yes.

• 51:23Brian Cox?

  The point is that Europa, Jupiter's moon, is a prime candidate for a habitable world. In what we know, almost certainly, I'm always, the people who I know who work on the mission say, don't say we know, we're almost sure there's a saltwater ocean below the surface. I think it's pretty indisputable now, so we're pretty sure it's there.

• 51:45Neil deGrasse Tyson?

  Yeah, but whatever is the skepticism, what would it be were it not? A global ocean.

• 51:50Brian Cox?

  Yeah, it's very difficult to be because and that's from many measurements.

• 51:53Neil deGrasse Tyson?

  Was it made of ammonia? I mean, there's not, you know, water molecule is not rare.

• 51:57Brian Cox?

  Yeah, it looks like salt water.

• 52:00Neil deGrasse Tyson?

  Yeah, and and we have a lot of comparative planetology with is it the Arctic? When it freezes over, you have these chunks of ice that will break and refreeze and readjust. And and you can compare the images and you'd think you were looking at the frozen Arctic.

• 52:15Brian Cox?

  Yeah, yeah. So it it looks and there's more water in that ocean than all the oceans of the Earth combined. Geologically active, there are questions about how the ice cracks and moves on the surface. So it's a fascinating mission. So that's Europa, Mars, of course, which you've probably spoken about many times on this podcast. And Celadus is another one, Saturn's moon, even even that's a pluto.

• 52:38Neil deGrasse Tyson?

  And so it's the ones we see, the plumes of geysers, I guess.

• 52:43Brian Cox?

  Yeah.

• 52:44Neil deGrasse Tyson?

  When at the right sun angle, you can see, who who took those pictures? That must have been Cassini, right, right, right.

• 52:51Brian Cox?

  Yeah, and also there's some measurements from Cassini. The particles in those jets of water, which are consistent with hydrothermal vent activity on the floors. And hydrothermal vents are one of the plausible candidates for the origin of life on Earth.

• 53:07Neil deGrasse Tyson?

  Yes.

• 53:07Brian Cox?

  So you seem to have everything. The one thing I think Europa's got that arguably nowhere else has is it looks like that ocean has been there for many billions of years. That's the the baseline scenario.

• 53:20Neil deGrasse Tyson?

  And we evolved life in less time than that here on Earth.

• 53:23Brian Cox?

  Yeah, yeah, I mean, it was present, what, 3.8 billion years ago.

• 53:26Neil deGrasse Tyson?

  3.8 ish, yeah, yeah.

• 53:28Brian Cox?

  And the Earth's four and a half billion years old.

• 53:30Neil deGrasse Tyson?

  Right.

• 53:30Brian Cox?

  Yes, so it looks like you have a habitat that's been stable there. And I think that you can't blame that with.

• 53:35Neil deGrasse Tyson?

  In fact, you know, it was taught that it took about a half a billion years on Earth to get life going. But we were able to revise that number down. Because in the early Earth, these periods of heavy bombardment, it's not fair to start the clock while we're still getting slammed by, you know, still accreting leftover rocks from the solar system. As the temperature of the surface of the Earth is high enough to prevent complex molecules. Give us a chance, please. So the, the periods of bombardment subside, Earth's surface cools, now start the clock. And then it's about a hundred, hundred million years.

• 54:10Brian Cox?

  Yeah, yeah.

• 54:11Neil deGrasse Tyson?

  And it's like that.

• 54:12Brian Cox?

  Yeah, which is one of the reasons, I think, that, I think, if you speak to many biologists, they would say that that might suggest that, given the right conditions, then wherever the origin of life is, there's a reasonable probability, given the right conditions, because it happened quickly here.

• 54:28Neil deGrasse Tyson?

  Right.

• 54:29Brian Cox?

  So but that now, that's not, that's not definitive in any sense.

• 54:31Neil deGrasse Tyson?

  But it's certainly tempting to go there.

• 54:34Brian Cox?

  But then, but what I find very interesting, Dan, is though, when you ask, okay, but when did life get more complex than a single cell? You're, you're then, I don't think there's any evidence in the fossil record back beyond about 600 million years ago.

• 54:47Neil deGrasse Tyson?

  It took a while. Yeah, we, we languished as single-celled creatures.

• 54:51Brian Cox?

  Three billion years.

• 54:52Neil deGrasse Tyson?

  Yeah.

• 54:52Brian Cox?

  Plus, but it seems.

• 54:54Neil deGrasse Tyson?

  So I think people who think about this problem are honest about that. And so in the search for life on other planets, we're really looking for single-celled organisms.

• 55:03Brian Cox?

  Well, it would be, it would be remarkable to see anything more complex. Well, it'd be remarkable to see a single cell. Cause then you'd know.

• 55:12Brian Cox?

  Especially if it were biologically different. So you can really show that it's got a different origin. Cause it's worth saying that on Mars, the materials exchanged between Earth and Mars. So it's not obvious.

• 55:21Neil deGrasse Tyson?

  Yeah.

• 55:22Brian Cox?

  That you couldn't have.

• 55:22Neil deGrasse Tyson?

  You make all these points in your series.

• 55:24Brian Cox?

  Yeah.

• 55:24Neil deGrasse Tyson?

  Right. So where, where, where can people find your series? It's streaming, I presume.

• 55:28Brian Cox?

  Yeah, yeah, we've got, the new one is just on at the moment, actually.

• 55:31Neil deGrasse Tyson?

  That's what I'm gonna say.

• 55:31Brian Cox?

  The solar system, so that will appear on Apple, I suppose, at some point. And, and other places, yeah. I mean, at the moment, it's on the BBC. So, um, and it's streaming on the BBC, and then it will head off around the world. One of the coolest things, I think, about Europa is that the, the habitat. The potential habitat requires Jupiter because of the heating, it's liquid because of the it's orbiting around a big planet. But it also seems to require, well, it requires the other moons, Io and Ganymede, to keep it in this orbital resonance, which keeps feeding the energy in from the gravitational field.

• 56:07Neil deGrasse Tyson?

  The family affair.

• 56:08Brian Cox?

  But it also might need the material from the volcanoes of Io on the surface of Europa, because they might provide the, what we call the oxidant, right? So that, so, so life is...

• 56:21Neil deGrasse Tyson?

  So you're saying that the, an Io, which is badly stressed...

• 56:27Brian Cox?

  It's just one big volcano.

• 56:28Neil deGrasse Tyson?

  It's one big volcano. So it spews volcanic substance faster than its escape velocity, apparently.

• 56:36Brian Cox?

  Yeah, which lands on Europa.

• 56:39Neil deGrasse Tyson?

  And it goes into pathways that intersect other moons, Europa included. And you do this for a billion years.

• 56:46Brian Cox?

  And then the chemistry, and then it gets irradiated.

• 56:49Neil deGrasse Tyson?

  It helps out the chemistry.

• 56:50Brian Cox?

  Yeah, so we, it, one of the theories that I've spoken to people who are on the Clipper missions said, is that that's part of the battery of life, that chemistry. So life, I can't remember who said it, but he said life, it was, someone said it's light, it's an electron looking for a place to land. That's what life is. There's just, in one way, you can see life as electrons moving around. But that means you need the chemistry for it to...

• 57:14Neil deGrasse Tyson?

  Is that all we are? Just electrons looking for a place to land?

• 57:17Brian Cox?

  Well, that's, that's what a description...

• 57:19Neil deGrasse Tyson?

  I'd rather be dust in the wind. Whatever. All we are.

• 57:23Brian Cox?

  So, but I find that wonderful, because then you've got this habitat, which is a system. And as you said, comparative planetology, you mentioned earlier, it's also true of Earth, isn't it? You can't understand Earth without understanding the system, the solar system. You need to understand the moon and how it stabilizes the spin axis, and you need to understand, of course, the sun, the way it interacts with Earth and so on.

• 57:46Neil deGrasse Tyson?

  I'm a few years your senior, I don't know if you would remember this, but I definitely do, the era where no one was thinking or caring about moons in the solar system. You know, we had a, we have a dead moon orbiting us, oddly large, but fine, let's go look at the planets. And so every mission out to the planets, we, they looked over their shoulder and found moons which had way more...

• 58:09Neil deGrasse Tyson?

  Geological diversity than anything we're finding on the planet.

• 58:12Brian Cox?

  You know, I found it interesting because you.

• 58:14Neil deGrasse Tyson?

  I mean, when you were in school, did where were we?

• 58:17Brian Cox?

  Pre voyage, well, voyage, so.

• 58:19Neil deGrasse Tyson?

  See, I'm pre Voyager and Voyager turned the moons into worlds.

• 58:22Brian Cox?

  Yeah.

• 58:22Neil deGrasse Tyson?

  That's what happened.

• 58:23Brian Cox?

  Yeah.

• 58:23Neil deGrasse Tyson?

  Yeah.

• 58:24Brian Cox?

  So the idea of a habitable zone in a solar system, which is the the zone within which if you have a rocky planet orbiting and everything's right, then and the atmosphere is right. You could have the conditions to support life on the surface.

• 58:36Neil deGrasse Tyson?

  Liquid water.

• 58:36Brian Cox?

  Liquid water, let's say.

• 58:38Neil deGrasse Tyson?

  Right.

• 58:38Brian Cox?

  And so and so.

• 58:40Neil deGrasse Tyson?

  But that turned out to be needlessly limiting.

• 58:42Brian Cox?

  Well, exactly. So you just say, well, Mars, Earth, Venus in our solar system.

• 58:47Neil deGrasse Tyson?

  That's it.

• 58:48Brian Cox?

  But then you find habitable zones around gas giants that and that, as you said, that was the great discovery of Voyager, I would say.

• 58:56Neil deGrasse Tyson?

  Yeah, it began with Voyager, really, for sure.

• 58:58Brian Cox?

  Yeah.

• 58:58Neil deGrasse Tyson?

  Yeah.

• 58:58Brian Cox?

  It should be nineteen, early nineteen eighties, right?

• 59:00Neil deGrasse Tyson?

  So I'm delighted, even as a particle physicist, you get to also platform the solar system because you have the name recognition.

• 59:08Brian Cox?

  I was always, but that's why I said I started with astrophysics. I really just wanted to be an astronomer. So I've always been, I've got a telescope.

• 59:15Neil deGrasse Tyson?

  You confessed to me.

• 59:17Brian Cox?

  I did.

• 59:17Neil deGrasse Tyson?

  It's a safe space to do that.

• 59:19Brian Cox?

  I ended up in particle physics. It was almost, so I was doing astrophysics. That's what I was doing. And I thought I want to be an astronomer. Well, University of Manchester has the Jodrell-Bang Radio Telescope, for example, which is one of the big radio telescopes in the world still. And so I.

• 59:32Neil deGrasse Tyson?

  That wasn't the one that discovered the first pulsar, was it?

• 59:34Brian Cox?

  Uh, no, that was Cambridge.

• 59:36Neil deGrasse Tyson?

  Cambridge, Cambridge, okay.

• 59:37Brian Cox?

  Justine Bell.

• 59:37Neil deGrasse Tyson?

  Jodrell-Bell discovered something else. I mean, just Jodrell-Bang.

• 59:41Brian Cox?

  It was one of the first, so it's one of the pioneering, it's a, does a lot of the work on the crab pulsar and so on. But it was, so I thought I'd be an astronomer and I have a telescope. That's what I do. I sit there and look at my telescope.

• 59:53Neil deGrasse Tyson?

  We'll accept you in the club, even though you you you drifted to particle physics.

• 59:58Brian Cox?

  And space exploration. So that's all what, but it was at university. I just got interested in mathematics. I didn't think I was very good at mathematics at school. And but I found out with a bit of practice, then I I enjoyed it. So I ended up really getting more into theoretical physics and went that way. So that's why I ended up in particle physics, really. But then now, of course, I've every every opportunity I get, I seem to drift back.

• 1:00:26Neil deGrasse Tyson?

  Because the universe is cool, you know.

• 1:00:27Brian Cox?

  And black hole.

• 1:00:28Neil deGrasse Tyson?

  I want to brag about the universe, but.

• 1:00:30Brian Cox?

  And black holes, actually, are where they intersect. They absolutely, particle physics and general relativity.

• 1:00:38Brian Cox?

  Astronomy.

• 1:00:38Neil deGrasse Tyson?

  And the Big Bang itself.

• 1:00:40Brian Cox?

  Yeah.

• 1:00:41Neil deGrasse Tyson?

  Yeah.

• 1:00:41Brian Cox?

  Yeah.

• 1:00:41Neil deGrasse Tyson?

  Yeah. With your particle physics hat, where are we with neutrinos now? I thought they're sort of fully understood. We solved the neutrino problem in the sun. A Nobel Prize was given for that. Is there anything left to discover?

• 1:00:55Brian Cox?

  Oh, yeah.

• 1:00:56Neil deGrasse Tyson?

  This elusive particle that belongs in the, in the, I would say, tree of life, in the particle tree of life?

• 1:01:02Brian Cox?

  Yeah, I mean, there are, neutrinos are fascinating things. They're very, very, very, they're almost massless, but not quite.

• 1:01:10Neil deGrasse Tyson?

  And that matters.

• 1:01:12Brian Cox?

  That should ring bells, you know, it's like, why? That's the thing with science, isn't it? You go, well, why is this unusually light? Or maybe it isn't, maybe the other things are unusually heavy, but, but, but it's telling us something.

• 1:01:22Neil deGrasse Tyson?

  And it's only neutrinos, how hard it is to interact with them, that gives me any belief at all in some other set of particles that might exist that we don't interact with? Because neutrinos are our own species.

• 1:01:36Brian Cox?

  Well, they interact through a, the weak force.

• 1:01:39Neil deGrasse Tyson?

  Yes.

• 1:01:39Brian Cox?

  They're interacting.

• 1:01:39Neil deGrasse Tyson?

  But that's us, that's our little world here, right? Any other symmetric particles, there are other forces that mediate them, is that correct?

• 1:01:48Brian Cox?

  There would be, so if you have sort of extensions to the standard model of particle physics, then you can have forces that change things into other things, and so different forces. But as far as we know, as far, the zoo that we have discovered is described by the three forces. The strong nuclear force, the weak nuclear force, electromagnetism, and then hanging out there, as we've discussed, is gravity in really a different framework at the moment.

• 1:02:17Neil deGrasse Tyson?

  So I corralled Steve Weinberg in an elevator one day, and a physicist, I'm telling you, I'm telling the audience, a particle physicist.

• 1:02:28Brian Cox?

  One of the greats.

• 1:02:29Neil deGrasse Tyson?

  Yeah, and he went to my high school.

• 1:02:31Brian Cox?

  Did he?

• 1:02:32Neil deGrasse Tyson?

  Allow me to add, one of our eight.

• 1:02:33Brian Cox?

  Nobel Prize winner.

• 1:02:34Neil deGrasse Tyson?

  One of our eight Nobel laureates from my high school. And I said, how can you live with yourself at night, given how many particles there are? Come on, I lost count. What does, what does this mean about our universe? And he said, it's not how many particles there are.

• 1:02:56Neil deGrasse Tyson?

  It's how many laws we have that describe them all.

• 1:03:00Brian Cox?

  Yeah.

• 1:03:01Neil deGrasse Tyson?

  And it's only just a few.

• 1:03:02Brian Cox?

  Yeah.

• 1:03:03Neil deGrasse Tyson?

  I thought, damn, good answer.

• 1:03:05Brian Cox?

  Yeah, he's, I remember Stephen Weinberg.

• 1:03:08Neil deGrasse Tyson?

  Good answer.

• 1:03:09Brian Cox?

  I think I'm right in quoting him as saying that he almost wished black holes didn't exist because they're so perplexing that it would be just easier. And he was kind of joking, of course, because physicists love a mystery. But he was almost like, this is too difficult, this is too bizarre. Maybe nature doesn't make them.

• 1:03:29Neil deGrasse Tyson?

  Oh, I got it. So you see, he's invoking human limitations on the capacity of nature.

• 1:03:35Brian Cox?

  He was kind of joking. He was just saying these things are so baffling and so weird. In some ways, I'd rather they weren't.

• 1:03:40Neil deGrasse Tyson?

  Did he say that in his old age so that he was getting tired of solving the universe?

• 1:03:45Brian Cox?

  He was joking.

• 1:03:46Neil deGrasse Tyson?

  So we're still trying to explore neutrinos. And as I understand, there's a new neutrino experiment that just came online.

• 1:03:54Brian Cox?

  I mean, there are several. I mean, I, so, I mean, the fundamental question, they do seem, the reason we're interested in them, just we're interested in them because they're three of the 12 fundamental particles, right?

• 1:04:09Neil deGrasse Tyson?

  Okay.

• 1:04:09Brian Cox?

  So we are made of basically three particles. That's us.

• 1:04:15Neil deGrasse Tyson?

  And the electrons, protons, neutrons?

• 1:04:18Brian Cox?

  Well, no. So the protons and neutrons are made of quarks.

• 1:04:20Neil deGrasse Tyson?

  Oh, so, okay.

• 1:04:21Brian Cox?

  So quarks, down quarks.

• 1:04:22Neil deGrasse Tyson?

  Let's start from the Greek. We're made of atoms.

• 1:04:25Brian Cox?

  You can start with, we're made of atoms. And we're atoms made of.

• 1:04:28Neil deGrasse Tyson?

  Greek means indivisible.

• 1:04:30Brian Cox?

  Yeah.

• 1:04:31Neil deGrasse Tyson?

  That's what that word means.

• 1:04:32Brian Cox?

  Yeah, and it is remarkable, by the way. You say the Greeks 2,000 years ago, we only discovered that the structure of atoms in the 20th century.

• 1:04:42Neil deGrasse Tyson?

  Or that atoms existed.

• 1:04:43Brian Cox?

  Well, yeah, it was up for debate. The turn of the 20th century, it was one of the debates in science. Is there such a thing as an atom?

• 1:04:50Neil deGrasse Tyson?

  Yeah.

• 1:04:50Brian Cox?

  It's incredible.

• 1:04:51Neil deGrasse Tyson?

  Incredible, yeah, yeah.

• 1:04:52Brian Cox?

  And Einstein, indeed, in 1905, one of his famous papers was on Brownian motion, which one of the three famous papers in that year. One of the other one was special relativity. And the other one, when he got the Nobel Prize for was the photoelectric effect. So the third one.

• 1:05:06Neil deGrasse Tyson?

  Yeah, Einstein, we should just retroactively give him like a dozen Nobel Prizes.

• 1:05:10Brian Cox?

  It's astonishing.

• 1:05:10Neil deGrasse Tyson?

  Yeah.

• 1:05:11Brian Cox?

  He didn't get the Nobel Prize for relativity. He got it for basically the foundation to quantum mechanics.

• 1:05:16Neil deGrasse Tyson?

  Yeah, yeah.

• 1:05:16Brian Cox?

  We discovered that matter's made of atoms. And then we very quickly discover after that that the atom is a electrons. Initially, we had this almost solar system like model that it's a nucleus, a dense nucleus with an electron going around it. And then we discover the nucleus is made of protons and neutrons. That's 1930s, by the way.

• 1:05:37Neil deGrasse Tyson?

  That orbit model is still the symbol for an atom.

• 1:05:40Brian Cox?

  Yeah.

• 1:05:40Neil deGrasse Tyson?

  You know.

• 1:05:41Brian Cox?

  Yeah, the atomic.

• 1:05:42Neil deGrasse Tyson?

  We kept it just because it's classic, you know, but that's atoms look nothing like that.

• 1:05:46Brian Cox?

  No, no, no. And so then quantum mechanics comes in, tells you you can't have that because charged particles moving around in the vicinity of other charged particles radiate energy away and they wouldn't be stable. And that was known, of course. And so then you find that the nucleus is made of protons and neutrons. And as I said, the neutron, it's a 1930s discovery. So we're not that long ago.

• 1:06:05Neil deGrasse Tyson?

  I'm amazed when so much, you know, we're now in the centennial decade of the discovery of quantum physics back in the 1920s. And the whole 1920s was done before we discovered the neutron. That's crazy.

• 1:06:19Brian Cox?

  Yeah, it's, it's, it's almost living, it is living memory for some people just about this.

• 1:06:25Neil deGrasse Tyson?

  Okay, so let's get back to the fundamental particles.

• 1:06:28Brian Cox?

  Yeah, then, then we discovered that the protons and neutrons are made of quarks.

• 1:06:30Neil deGrasse Tyson?

  Quarks.

• 1:06:31Brian Cox?

  So they are, as far as we can tell, point like objects, that they're fundamental. They won't be, but as far as we can tell, they are experimentally.

• 1:06:40Neil deGrasse Tyson?

  So we have the photon, the electron.

• 1:06:43Brian Cox?

  Well, let's take the matter particles. So we have, so the up and down quarks make up protons and neutrons. So a proton is, is two ups and a down, and a neutron is two downs and an up.

• 1:06:52Neil deGrasse Tyson?

  Got it. And we have two quarks per energy stratum here, correct?

• 1:06:58Brian Cox?

  Well, so then, so then we discovered, so we had this, we have this nice thing. So we have the electron, as you said, the up and down quark, and then the thing called the electron neutrino, which we, so we just talked about neutrinos.

• 1:07:11Neil deGrasse Tyson?

  Only four fundamental particles in anything we know or care about.

• 1:07:13Brian Cox?

  So we have four of them. Yep.

• 1:07:15Neil deGrasse Tyson?

  That's it.

• 1:07:15Brian Cox?

  That's it. And then we have.

• 1:07:16Neil deGrasse Tyson?

  So I can construct you out of these particles?

• 1:07:19Brian Cox?

  Yes.

• 1:07:19Neil deGrasse Tyson?

  If I had the recipes?

• 1:07:20Brian Cox?

  Yes. But then. So we have four of them. So that's it. There's four of them. And then the forces that mediate the interactions, right?

• 1:07:28Neil deGrasse Tyson?

  Okay.

• 1:07:28Brian Cox?

  And which we can also think of as being carried by particles, as we said.

• 1:07:33Neil deGrasse Tyson?

  Okay.

• 1:07:33Brian Cox?

  We have the photon.

• 1:07:34Neil deGrasse Tyson?

  The massless particles.

• 1:07:35Brian Cox?

  The electromagnetic force. We have the W and Z bosons, which do the weak nuclear force, and the gluons, which do the strong nuclear force and stick the quarks.

• 1:07:43Neil deGrasse Tyson?

  Aply name, gluon.

• 1:07:44Brian Cox?

  The gluons, yeah.

• 1:07:45Neil deGrasse Tyson?

  Okay.

• 1:07:46Brian Cox?

  And so that's it, it seems, except that there are two copies of those that are identical, except they're more massive. So there's the charm and strange quarks and the muon and the mu neutrino. That's another family.

• 1:08:04Neil deGrasse Tyson?

  That's the next level up in energy.

• 1:08:06Brian Cox?

  They're more massive.

• 1:08:07Neil deGrasse Tyson?

  More massive. Okay, okay.

• 1:08:09Brian Cox?

  So you have the charm and strange and the muon and the mu neutrino. And then

• 1:08:13Neil deGrasse Tyson?

  You have another one.

• 1:08:14Brian Cox?

  Yeah, which are the bottom and top, or sometimes called beauty and truth, depending on how you want to do it, the quarks, and then the tau and the tau neutrino. And that's it, as far as we can tell. So those are the massive particles.

• 1:08:27Neil deGrasse Tyson?

  Four, eight, twelve fundamental particles, and their antimatter counterparts.

• 1:08:30Brian Cox?

  Yeah, and then the antimatter counterparts. And so that, why, we don't know. So why there are three? And with experimentally proven, really, with some very small caveats, only three generations, only three families of these things.

• 1:08:49Neil deGrasse Tyson?

  Is there a reason for there to be only three? Could there be five or 10?

• 1:08:52Brian Cox?

  Yeah, so we don't know. It must be something to do with the underlying. So it looks like a periodic table. So remember, you go back to Mendeleev and the periodic table. How do you understand that pattern in the chemical properties of the elements? You understand it when you know that everything's made of atoms.

• 1:09:09Neil deGrasse Tyson?

  Yeah, I mean, the chemist arranged it, but didn't have any understanding of it.

• 1:09:13Brian Cox?

  No.

• 1:09:13Neil deGrasse Tyson?

  So quantum physics.

• 1:09:14Brian Cox?

  Well, you need to know the structure. You need to know that there's a nucleus and there's, you know, hydrogen's got one electron and helium's got two and carbon's.

• 1:09:21Neil deGrasse Tyson?

  I'll only get you so far.

• 1:09:23Brian Cox?

  Yeah. So you understand chemistry. You understand the pattern when you understand the building blocks.

• 1:09:28Neil deGrasse Tyson?

  Okay.

• 1:09:29Brian Cox?

  So we don't know why that pattern is there, but it's clearly telling us about the building blocks or the underlying theory, which we don't know. So it's one of the great mysteries. So that's the zoo of particles, as we know. And then there's the Higgs.

• 1:09:43Neil deGrasse Tyson?

  And just to be clear, when I attacked Steven Weinberg in the elevator, most of the particle identities I was referencing. Are different combinations of different quarks.

• 1:09:53Brian Cox?

  Yeah.

• 1:09:54Neil deGrasse Tyson?

  That come together.

• 1:09:54Brian Cox?

  Yeah, so all these, you said in the 50s and that people were discovering all these things. And they're different combinations of ups and downs and strange and charm and bottom and so on.

• 1:10:07Neil deGrasse Tyson?

  So they exist in our universe, but again, they're made of the more fundamental.

• 1:10:11Brian Cox?

  Yeah, so basically, these things, the proton and neutron, they're analogous to an atom in a way. So they're a thing, they're quite a big thing in particle physics, and they have an internal structure.

• 1:10:24Neil deGrasse Tyson?

  Within themselves, yeah.

• 1:10:25Brian Cox?

  And one of the things that I was involved in, that we did it back in Hamburg all those years ago, was we were mapping the structure of the proton. So we're saying, what is in the proton? How does it work?

• 1:10:35Neil deGrasse Tyson?

  Mapping the interior structure of the proton.

• 1:10:36Brian Cox?

  And we need that, we needed that for the LHC. So we need, because we collide protons together. So we have very detailed maps, if you like. They're called structure functions, but they're maps of the proton.

• 1:10:48Neil deGrasse Tyson?

  Well, Brian, thank you.

• 1:10:49Brian Cox?

  Pleasure.

• 1:10:50Neil deGrasse Tyson?

  For joining me.

• 1:10:51Brian Cox?

  I always love talking to you.

• 1:10:53Neil deGrasse Tyson?

  Oh, no, we're just kindred spirits in this world. And I wish you great success with your spring tour. Does it go beyond the United States? Is it a world tour?

• 1:11:04Brian Cox?

  It has been a world, so we've been to, I don't know, 20 or 30 countries. As I said, we were probably approaching half a million people who've come to this one.

• 1:11:12Neil deGrasse Tyson?

  Okay, so that's the, that would...

• 1:11:14Brian Cox?

  We're at the end, really, of this one.

• 1:11:17Neil deGrasse Tyson?

  Oh, okay.

• 1:11:17Brian Cox?

  And so I just wanted to bring it back here. It's changed so much. We started in the States, actually, in its proto-form. And now I've loved doing it so much, and I just wanted to bring it back.

• 1:11:30Neil deGrasse Tyson?

  I just like the idea that a science talk is being given, but there are trucks that have to unload the staging for it.

• 1:11:35Brian Cox?

  It's proper rock and roll. I got roadies, I've got everything.

• 1:11:39Neil deGrasse Tyson?

  Do you have a tour T-shirt with the cities on it?

• 1:11:42Brian Cox?

  Yeah, oh, yeah.

• 1:11:43Neil deGrasse Tyson?

  All right.

• 1:11:44Brian Cox?

  I should have brought one to show you.

• 1:11:45Neil deGrasse Tyson?

  I want one of those shirts.

• 1:11:46Brian Cox?

  Yeah.

• 1:11:46Neil deGrasse Tyson?

  Oh, my God.

• 1:11:46Brian Cox?

  Oh, we've got everything. And we've done so many shows. And how many is 150, 200? They don't all fit on one T-shirt. So we've got different T-shirts for different regions of the world.

• 1:11:57Neil deGrasse Tyson?

  Physics takes the world. Very good, Brian. Again, thanks for being on the show. This has been an exclusive conversation between me and my good friend Brian Cox from the UK, who's coming stateside. With a tour and we're going to look for the solar system on It should be around, yeah. Yeah, it does its BBC. How many, how many episodes is it? Five. Five episodes. We'll look for it. All right. This has been StarTalk. I'm your host Neil deGrasse Tyson. As always, keep looking out.