Episode #2 Transcript: Space: A journey through the Universe, in search for meaningful answers… with Professor Brian Cox.

[(4:37)] Martin: Can I kick off and start the question? The question that I would like to start with is, Is the universe eternal? First of all perhaps, Brian, you would like to define why that is important as a question.

[(4:51)] Brian: It is a good question and the very short answer is we do not know. That is a surprising thing to say though because what we do know is that 13.8 billion years ago, the universe was very different indeed from the universe that we see today. Today we see this universe full of stars and planets and galaxies, complex structures. What we know is that as you wind time backward and you go back 13.8 billion years, there were no stars, no planets, no galaxies. The universe was very hot and very dense and we call that moment, if you like, in the history of the universe; the Big Bang. It has always been synonymous with the origin of the Universe. I think in most people’s minds. Indeed that is the way that…

[(5:37)] Jax: So hold on, was it a state? The Big Bang? It was not like a moment. You are saying it was a state. 

[(5:44)] Brian: Well, that is the key point. We used to think that… If I rewind a bit, the framework that we use is Einstein’s theory of general relativity. It was published in 1915. That theory strongly suggests that the universe is not stable in the sense that it should be expanding or contracting. Einstein actually resisted that. So the theory is really strongly suggesting that space itself should be stretching or shrinking depending on how much stuff is in it. Most people at the time, I think Einstein included, thought that the universe should be eternal because it just feels better. You know you do not have to deal with thorny issues about a moment of creation or the origin of what caused the universe to come into existence. Whatever you want to say. 

[(6:31)] Jax: Is that not a cop-out?

[(6:33)] Brian: Well many people thought. Well, it is a good question, is it not? So we will get to that. So I think most people kind of thought it was eternal. Although obviously then you have various religions with creation myths and so on. But Einstein’s theory strongly suggests that it should be changing. Then the observation in the 1920s by people like Edwin Hubble, showed that the universe is indeed stretching. The fabric of the universe itself is stretching. The universe is expanding. That caused people like George Lemaitre who was one of the founders of cosmology. He was a very interesting man actually, a Belgian priest as well as a physicist and a mathematician. It caused him to say that it seems the universe had a day without a yesterday. Because if you just imagine, if the universe is expanding today then that means yesterday, everything was closer together and you can rewind time until everything is on top of each other. We call that the Big Bang. So that is kind of what you learn in school, right? That is the basics of the picture we have of cosmology. But whether or not that time when the universe was hot and dense is indeed a day without a yesterday. If that is the first moment or whether the universe existed in some other form before that and indeed whether that other form goes into the infinite past. It is just not known. I should say we strongly suspect the universe was in existence before it got hot and dense and that is a theory called inflation. It is essentially the idea that the universe was empty and cold, pretty much, before the hot big bang and expanding very rapidly indeed, and that expansion drew to a close. All the energy driving the expansion was kind of dumped into space which heated it up and made the particles out of which we are made. But when that began or if that began, honestly, we do not know.

[(8:25)] Jax: I struggle, I guess, with my limited human brain to take on the idea of infinity. Like what you are saying is that it has always been there. That just does not work for me. Do you know what I mean? 

[(8:38)] Brian: Well, I do not know. Especially I do not know whether it has always been there but nobody does. But it is interesting, is not it? Because the universe has an infinite future which we think of again, it probably may well have. That does not seem to bother us as much. I do not know whether it bothers you. 

[(8:56)] Jax: Yeah, I am kind of… It just leaves me… The emotion is more hopeful like okay cool, that is fine. And then there is not knowing where I began. I am speaking on behalf of the whole of the human race. It is slightly less comfortable. I am like, oh, okay. I guess you are looking for meaning, right? Why are we here? Do you know what I mean? How did we get here? 

[(9:19)] Brian: I think that is very important. The point actually, if you think about that question. What does it mean to be human? It does not sound like a scientific question. But in fact, what I would argue is that science provides the words are “necessary but not sufficient” framework. In other words, if we are going to approach that question. It is necessary to know that there are two trillion galaxies in the observable universe. The universe is at least 13.8 billion years old. The Earth formed four and a half billion years ago. There are 400 billion stars in the Milky Way galaxy. All those things are necessary to try and answer that question, but they are not enough on their own. I think that it is really an important point about the way that science fits into the culture and to our culture and our civilization because you cannot address deep questions without it. But that is not to say that it will answer all your deep questions. 

[(10:23)] Martin: I think that is a question of relevance. Is our place on Earth albeit time-based or at least we think it is physically time-based, maybe our soul goes somewhere or whatever? But we were concerned about what we do not know in as much that it might affect what we currently have today. Whereas if we were to wind forward a thousand years, I think most people are thinking, “Well, it does not really matter because it is not as relevant because I am not going to be participating in that journey.” 

[(10:56)] Brian: You think because you know legacy is something that many people feel they want to leave. They want to leave something for future generations. You see it now. I mean, serious issues such as climate. It is an interesting point you make. I think some people feel that because it does not appear to be a problem very imminently, although actually, that has changed in the last few years. It is becoming quite obvious now. But if you go back ten years, I think people felt that if you get a prediction saying in a hundred years time, there are going to be problems and I think you are right. Some people just switch off at that point and here we are talking about well, tens of billions, hundreds of billions of years in the future. 

[(11:39)] Martin: We all have some form of legacy that we care about. But something that is going to affect… It is not going to be around in a hundred years. Let alone a thousand years. It is almost out of grasp. Whereas right now, we stand on the ground. We use this concept called time and yet we do not really know why we exist at all. So the burden is whether it is a risk to humanity. Maybe it gets to some of the creation myth. It certainly gives us fabric for why religion exists because it bridges the unknown. I mean, is that how you see the creation myths? This idea that there is a suggestion of a God because it is not eternal.

[(12:21)] Brian: There are a lot of things to kind of unravel what you said. I mean, a basic point is if you think what science is, it is people who take delight in the unknown because you cannot do research without that. Research means that you are standing on the edge of the known, looking out into the unknown and enjoying that. You are not making something up. You accept that there are things that you do not know and then you set out to try and discover as much as you can about the things that you do not know. That is a different mindset, I think. On the other side of the coin, the other extreme is that we are afraid of the unknown. So you either decide not to go there, you do not open the door, you just hide or you just invent stuff. You just make stuff up. You just do not want to say I do not know for whatever reason. It bothers you and I think that is a really important point. There is a very famous essay, which I would recommend to everyone if you have not read it. It is called, “The Value of Science” by Richard Feynman, who is a great hero for virtually all scientists and physicists. Anyway, we all wanted to be Feynman at some point. Nobel prize-winning physicist, tremendous character, great book. “Surely You’re Joking, Mr. Feynman!” which is a collection of stories about him. But he wrote an essay in 1955. I think it is available on the web. MIT has made it publicly available, it is called “The Value of Science” by Richard Feynman, you type in and you get it. In that essay, he came out of the Manhattan Project. So he works on the atomic bomb with Oppenheimer and others. He says in the preamble that he was surprised he was even alive in the 50s because there is a strong feeling from Feynman, Oppenheimer, and other the people who worked on the atomic bomb that they delivered power to the politicians and society that politicians and society could not control. They were pretty right. They are almost right. You go forward a few years, there is the Cuban Missile Crisis, and so on. They were not far off. What it caused many of them to do is reflect on the value of this mode of thought. 

Brian: As I said, science is embracing the unknown and he said that probably, the most important thing of all and not the things, like in today’s language; the iPhones, the computers or the internet, or the vaccines that science delivers. Those things are not the most important. It is the mindset and the mindset is accepting the fact that we do not know everything. Accept that. That is the basis. That is the foundation on which all reliable knowledge, I would argue, that we have today about nature and the universe is built. It is because someone said I do not know. If you extend that, the more people we have in our society, particularly in positions of power actually are prepared to say, “I do not know. We might try or the data is changed, right? I know some more now, so I will change my position.” The more people that know that the better. Just to finish, he said that if you think about what democracy is, the most valuable thing that seems to have nothing to do with science. It is the same idea because the most important thing about democracy is that you change the government. That is the most important thing. You change every four or five years, why? Because you accept that nobody knows how to run a society. That is why if you thought you knew, you would be a dictator and you would not change the government. Its a brilliant essay. 

[(16:13)] Jax: That is a beautiful, beautiful thought. Just in itself, in order to accept that you do not know something, you need to have the humility to say, “I do not know the answer.” That takes a certain maturity.

[(16:27)] Brian: And honesty, intellectual honesty. 

[(16:30)] Jax: I feel like what you are saying about standing on the edge of the known is that science might arrive at an idea that God did exist or does exist and that is what we have discovered. Do you know what I am saying? 

[(16:46)] Brian: Science is the study of nature and nature is reality. It is out there. Science is not to go around proving or disproving things or having some preordained idea of what nature is like. We are just trying to understand nature. If there are elements of nature that are completely incomprehensible to us at the moment but we stumble across them and we can observe them, then I would argue that they are then science because science is the study of nature.

[(17:19)] Martin: Just to go back on the 13.8 billion years. It is the concept of time, right? This is clearly human-made, the word time. But it is actually a very very important aging instrument that gets us to talk about. If I look in the sky, how do I know it is 13.8 billion years old? How do I know there is a couple of trillion stars? How do I know that is just not light refracting a certain way?

[(17:47)] Brian: It is a perfect question because it seems impossible, is not it? How can you know? How can you measure the distance to a star? 

[(17:57)] Jax: How can you? Did just decide?

[(17:60)] Brian: It was a tremendous effort. If you go back to the 16th century to the 18th century, the LHC or the Large Hadron Collider or the Apollo program of the time was trying to measure the distance initially from the Earth to the Sun, which is called one astronomical unit. That was done in a very subtle and clever way by watching something called the transit of Venus, which is when Venus floats across the face of the Sun. By watching it from different positions on the Earth, you can do some geometry. They were very smart and they figured out they could use this to find the distance from the Earth to the Sun. Once you have that, you use parallax, believe it or not, to get the distance to the nearest stars. 

[(18:47)] Jax: What is Parallax?

[(18:47)] Brian: Parallax is, you know, with your eyes, if you close one eye and close the other eye and something moves, right? You can see that it moved.

[(18:54)] Jax: No way. So that is like, your true aim is the one that does not move when you close the other eye, right?

[(19:00)] Brian: Yeah, so you knew that. I mean, it is because of the distance between your eyes. You get closer and closer and the angles change a bit, and you can see how far something is away. That is how you perceive depth to some extent. If you know the distance from the Earth to the Sun then you can look at the position of a star in the sky, let us say in January. Then look at it in July, and you have gone halfway around the Sun. So your eyes, in that case, are twice the distance from the Earth to the Sun by 18 billion miles or something like that.

[(19:32)] Jax: That makes sense.

[(19:33)] Brian: You see the stars shift a bit because it is just the same as doing that from January to July. That is how you do the distance to the nearest stars. From then what happens is you try to find some relationship between the brightness of a star and something else that it does. There are things called variable stars, which vary, so they go light and dark and light and dark. They vary in a way that is proportional to how bright they actually are which is what we call cepheid variables. If you know how bright something is actually, and you know how bright it looks, then you can calculate how far away it is right? Because the further away, the dimmer it is. That is another way of doing it. Then we have things called type 1A supernovae explosions which are very bright. We know how bright they actually are and we can see them in distant galaxies. That allows us to tell how far away the galaxies are. Then finally, which goes to the end of your question, you find that if you look at very distant galaxies, then the light from them is stretched. It means it goes redder because longer wavelength light is redder. It is called Redshift. You find that the further away the galaxy is, the more stretched the light is. It is a direct measurement you can make and that tells you how fast the universe is expanding because what has happened is the light has been traveling across space for 50 million years or 100 million years or sort of billion, whatever. You can see them up to 10 billion years or something like that. 

[(21:13)] Jax: That is crazy.

[(21:14)] Brian: It means that the light has been traveling for 10 billion years across the universe and if it is stretched by let us say a factor of three, then it tells you the universe has stretched by a factor of three during that time. That allows you to measure the expansion rate of the universe. If you know how fast it is expanding in all these different times, then you can wind it back using Einstein’s theory actually to go back when everything was on top of each other. It is a whole thing that began back in the 1600s and 1700s with these missions around the world on sailing ships to measure the transit of Venus and then you get the distance and you get another distance and another distance. It is called the distance ladder. It is a story that spans centuries. This idea that people just wanted to measure distances. The distance to the stars. That is how you do that. 

[(22:06)] Jax: Can I ask a really stumpy question? So you have got the distance ladder. You are mapping the stars essentially. You quoted and there were some incredible numbers, you know all the numbers of a heart like that. But also the size, it is so hard to comprehend, right? In the physicist world do people pick up where the other person left off to continue the mapping?

[(22:34)] Brian: It is really exciting because now there is a satellite up there called Gaia, which is a satellite that is mapping the positions and speeds of stars in the Milky Way. It is doing thousands and thousands of them. It is building a 3D map of the galaxy and it is measuring how the stars are moving. If you know where the stars are and how they are moving then you can run that movie forwards and backward in time. You can see the history of the galaxy and the future of the galaxy. By doing that, this data is allowing us to say that five billion years ago, there was a collision between two smaller galaxies in the Milky Way. You can see those stars still orbit in a different way around the Milky Way today and trace that all back. You can do galactic archaeology and you start to see how the galaxies evolved. You start to see that there are connections between collisions between galaxies and the formation of our solar system because these collisions affect star formation rates and things. You could start to think, well, is it possible that we exist and we are talking now because of a galactic collision that happened seven billion years ago? We are at the level of precision where we can start to talk in those terms and answer questions like that. 

[(24:00)] Jax: When is it going to be? I do not know. When will they finish all the data?

[(24:02)] Brian: It is up there now.. I do not know exactly when it has taken data but its data set is being analyzed now. I think it is probably still taking data actually, but I cannot quote. I do not know the answer to that question, but I think it is still. I could go on my phone and check.

[(24:25)] Martin: Quick question to the layman, space and scientists have used this term “number of light-years away” perhaps you want to give a little definition of why we need to measure in light-years. Why do not they just say look we are five and a half years away from getting to Pluto or whatever, right?

[(24:43)] Brian: It is because light is one of the strangest things in the universe but is is one of the most useful because it always travels at the same speed. It is what is called a constant of nature. No matter how the thing that emits the light moves or how the things moving that is going to receive the light travels… There is a great book. I am recommending a book now. There is a great book on Relativity by Robert Geroch. It is kind of an older book now, but he is one of the great experts. He said in that book that light seems to care about space and time; the fabric of the universe. It does not care about what admitted it or what received it, it just goes along. So it is a perfect measuring instrument because it always travels at the same speed. It does not matter if the thing that emitted it is flying away from you at 99% the speed of light. If it comes toward you, the light comes at the speed of light and goes past you. It allows you to measure distances which is why it is useful because a light year is the distance light travels in a year. If I said the distance a baseball travels in a year, you would say well that is a stupid unit of measurement because of how fast you throw the baseball. 

Light travels at the same speed. So that is why it is useful. It is much more than that though. Light because it travels at the same speed always and nothing travels faster than light. It defines what is called, the causal structure of the universe. So it tells us that if you have something that happens, can that something influence something else or not? Like for example, let us say, there is a year light travel time. Anything that is further away than a light-year for that time, within the space of a year, you cannot communicate with it. It cannot influence it. There can be no communication between the two because you would have to go faster than light to get from that place to the other event. Light plays a fundamental role in relativity. It is not only useful. It actually defines what is called the causal structure of the universe. That is where you get into, which we might talk about black holes and things because they are regions of space…

[(26:54)] Brian: …from which even light cannot escape.

[(26:58)] Martin: There is a forthcoming attraction. The movie is coming soon.

[(27:02)] Jax: By the way, just for anyone listening, with all the books and outside reading that is being referenced. We will be listing them for sure.

[(27:13)] Brian: Yeah, this one is a classic book and it is written in the 70s. It is one of the great textbooks on black holes and cosmology, Stephen Hawking and George Ellis.

[(27:24)] Brian: I have put myself on the spot now and it is a really ridiculous thing to do on the podcast because I was going to read something from the introduction. 

[(27:29)] Martin: Are you going to read us poetry?

[(27:32)] Brian: That means that I need to… It is a textbook, “The Large Scale Structure of Space-Time” by Hawking and Ellis. I cannot find it but it is somewhere in the introduction where it says that because… The thing is that light travels through space and time at this constant speed and divides it up into regions that can influence particular events and regions where events cannot influence other events. So they said in there, something about how gravity tells you how all that curves and bends and warms, right? In that sense, it determines the causal structure of the universe. That is what they say in the introduction. It is gravity that warps space and tells you which regions can influence other regions and which cannot. It is beautiful.

[(28:23)] Martin: We will come back to gravity for a moment. We want to get past that wonderful ice-breaking session and back to a quick definition of what is particle physics as it will pertain to the rest of the discussion. 

[(28:38)] Brian: Particle physics is the study of the smallest building blocks of the universe and the forces that operate between them. In particular, the force is excluding gravity. Gravity does not come into particle physics at the moment. It should do, which is where black holes come in again, which we will talk about in a bit. But at the moment the reason is, gravity is so weak as a force between particles that it is completely immeasurable. But there are three other forces in the universe. The familiar one is electromagnetism, which is electricity, magnetism, fridge magnets, and so on. That is one force and then there are two forces that operate in the atomic nucleus called the weak and strong nuclear forces and the things that stick the nucleus together and allow radioactive decay and so on. The study of those forces and their fundamental particles that interact through those forces that I would define as particle physics. 

[(29:40)] Martin: That is a fabulous definition. Can you just describe those latter two forces? Because I think for most people, electromagnetism, some people will get and you gave a quick description of how we might see that in everyday life. But perhaps you can just elaborate a little further on the other two forces that we can describe. 

[(29:57)] Brian: I mean, what I mean by force, by the way, is the means by which things interact with each other in the universe. So you are sitting on a chair now or standing on the floor or something. There are forces acting why you do not fall through the chair. There is something stopping you from falling through the chair and that is electromagnetism actually.

[(30:20)] Jax: Why is that electromagnetism, that I am not falling through the chair? 

[(30:24)] Brian: There are two bits to it. One bit is that there are electrons which are negatively charged things in the atoms of your chair and in your ass, whatever is the best way of saying that.

[(30:37)] Jax: I was wondering when you are going to tell me about the magnet in my ass, basically.  

[(30:42)] Brian: Like charges repel, so there is a force.

[(30:46)] Jax: Wow.

[(30:48)] Brian: Actually, there is also, it should be said, a quantum mechanical effect, where electrons do not like to be close to each other which is called the Exclusion Principle. So you try and squash them closely, they repel each other and they also try and avoid each other and the combination of those is what makes stuff rigid, solid, right? So why is a brick wall solid? It is ultimately those effect. So it is forces. That is all there is. That is how you perceive the universe. It is why you stick together. So there is electromagnetism which is a long-range force that is responsible for everything that we experience other than gravity. But if you go deep into the atom, there is an atomic nucleus and the electrons go around the nucleus. That nucleus is made of little things; protons and neutrons. But they are in turn made of things called quarks, which are the smallest things that we know.

[(31:40)] Jax: I have never heard of a quark. I have got as far as the nucleus. 

[(31:43)] Brian: You have two quarks and a down quark roughly in a proton, and two downs and one up in a neutron.

[(31:51)] Brian: So they make up the protons and neutrons. Those things are stuck together by something called the strong nuclear force, which is way stronger than electromagnetism at very short, but it does not leak out of the nucleus. It kind of fades away and so you do not see it. You cannot feel it. We do not really interact with it other than it is holding our atomic nuclei together. It is really important. Then the other one, the weak force is something that allows protons to turn into neutrons and that is really important because of what happens in the Sun. In the sun, the sun shines by taking hydrogen which is a single proton, and building helium which is the next simplest element. The helium nucleus is two protons and two neutrons. So what has to happen is a proton has to turn into a neutron before it can stick together to make helium nuclei in the Sun and that is the weak nuclear force. Without that, the sun would not shine, the stars would not shine. 

[(32:52)] Martin: It seems like an appropriate time to talk about the particle that might be missing, the Large Hadron Collider experiments at CERN. I understand you have been or are involved in that as one of the researchers or you participated. I know you visited it and all the rest of it. But if I frame it as, there is this particle that has been described or being named the Higgs boson particle or also a.k.a the God particle. Perhaps you would like to describe for people what that is, why it is significant, and what the hell is this big thing in CERN trying to do at the speed of light to collide these particles?

[(33:34)] Brian: Yeah, and then we have discovered it now. It exists, the Higgs particle. It was predicted by Peter Higgs and others actually in the 1960s. It was discovered in the 21st century.

[(33:46)] Jax: When you say it was predicted, what was it that they predicted?

[(33:50)] Brian: It was a physical theory, right? It is some sort of framework, usually, a mathematical framework that allows you to predict things. We have this framework called the Standard Model of particle physics which was developed really from the 50s and 60s onwards and really became sort of a full physical theory, I would say, in the 70s and 80s. Then that theory had a problem with it and it had a problem with mass. So fundamentally, mass. If you give an electron, for example, they have mass, right? It was measured back in the turn of the 20th century. The mass of the electron was measured and so if you just give particles mass in the theory, just mathematically write it in, then there were huge mathematical problems. You basically could not do it. And so the physicists had to find a way of giving particles mass without breaking the theory, without messing up the structure of the theory. The way they found was the Higgs mechanism which is essentially, what you do, is you introduce something else into the universe and things get mass by interacting with it. An analogy that is often used. It’s like wading through treacle or maple syrup or something like that. If you walk through stuff and it interacts with you and it slows you down, then you get kind of more massive. In that analogy, the correct thing to say is that particles get mass fundamentally. The fundamental particles like electrons are getting mass by interacting with the Higgs field which permeates the universe. That was a way of allowing the particles to have mass in the theory without messing the whole beautiful structure of the theory up. It predicted that there was this thing called the Higgs boson, a particle associated with this field that fills the universe which we should be able to make if we bang particles together with high enough energy. If we build a big enough particle accelerator, we should be able to make Higgs particles and observe them. That is basically what the LHC was. It was guaranteed because we knew what the theory predicted, that we would either find the Higgs boson at the LHC or some kind of Higgs boson or something else. Because the whole theory collapsed at those energies, that the LHC bangs things together. The whole theory collapsed without the Higgs.

[(36:36)] Martin: It was an inevitability.

[(36:37)] Brian: We knew what machine to build. It was not inevitable we would find the Higgs because that was just a prediction. Nature can be clever and smarter than we are, right? Its often is. It could have been something else and in fact my most cited paper. In physics and science, you measure success of the paper by how many people refer to it in their own papers. My most cited paper, which is like loads, hundreds and hundreds and  maybe thousands citations was physics at the LHC without a light Higgs boson. So I wrote it before we discovered it, with a couple of colleagues and it gets cited for some other stuff that was developed in it. But it just shows you that in 2000, which I think I wrote the paper in 2000. It was perfectly legitimate to think that the Higgs particle would not be found but something else, some more exotic mechanism would be found at the LHC. But then we found the Higgs, which is quite incredible, right? It was fifty years after it was predicted mathematically and there is a deep point that you can use mathematics to make a prediction about reality. In this case, the existence of a particle. It is a real thing and then fifty years later you build the world’s biggest experiment, twenty-seven kilometers in circumference underneath Switzerland and France and all the eighty-eight countries, I think, of the world came together to do it. You switch it on and you see the thing that this guy derived with a pencil in 1963 or whenever it was. That is a remarkable thing, is not it? 

[(38:16)] Jax: That is incredible because it just reminds me of what you said earlier about thinking in more of future tense and that you can think in that way with science and math, right? Again it makes you want to take it more seriously. Basically, it is what it makes me feel when you say that. 

[(38:36)] Brian: For the great mysteries, there is a physicist called Eugene Wigner. He is a very famous physicist, and he said that it is one of the great mysteries in mathematics. He called it the unreasonable effectiveness of mathematics. In the physical sciences, there is another essay that you [inaudible] this time. But it is true in some sense. It is one of the great mysteries that for some reason mathematics can be a guide to reality. Remember science is the observation of reality and the fact that you can predict things about reality using mathematics is interesting. It is a whole discussion about why that might be the case. 

[(39:18)] Martin: I think of math as just another language to explain life and that is why it is so powerful. It has its own construct, its own principles. But it is, at the end of the day, a language and way to express. You are right, it is incredibly powerful when you think we have got to go and build plant machinery. We need technology. We need to evolve, to get what the power of a pen and a mind had all those years ago. I have two very quick things on this if I might, one is that I just want, for the audience sake, in this 27 kilometers underground that you are accelerating these particles. They were traveling at the speed of light, right? 

[(39:60)] Brian: No, just below. Massless particles have to travel at the speed of light and anything with mass has to travel slower than the speed of light.

[(40:09)] Jax: It makes total sense. It makes total sense right now. 

[(40:12)] Martin: That is great. You may have already answered this, Brian. Forgive me if I am taking on a lot of information today. The God particle has been discovered. So what is the significance? What do we do now? Cool, so there is an answer to the question of mass. Then what happens? 

[(40:28)] Brian: To say by the way, the God particle, it was Leon Lederman, one of the great Nobel prize-winning physicist who invented that term. He wrote a book which got called the God particle. It was about the Higgs and the quest for it. But he subsequently said that he really hated that. I think he blamed it on his publisher and said it was total bollocks. 

[(40:47)] Jax: He didn’t like God?

[(40:50)] Brian: No, but he sold books, right?

[(40:53)] Jax: I mean it got me. I am not gonna lie. It got me.

[(41:00)] Brian: As I said the Higgs, as far as we can tell, is one of the fundamental components of reality, right? It was a new kind of fundamental particle that we had suspected and now we know it exists. It opens a door to a deeper understanding. Now one of the many things we are doing other than searching for other particles is to try and make as many Higgs particles as we can, so we can watch them and see how they behave, and observe them because we want to know. There are a lot of big questions about this thing. How it came to be here? How it fits in with a wider framework? We are just at the beginning. It is almost like discovering a planet and saying good we discovered it now. We actually want to go to the planet. We want to know. It is not quite right. It is a very important part of our understanding of fundamental physics. It is not the God particle, right? It is not the answer. It is not the end, it is the beginning. It is just another of those fundamental components, which is extremely important. 

[(42:09)] Martin: Yeah. Sure. Just to describe to the layman, when we say it gives us mass, is it fair to say that we exist because of this particle?

[(42:20)] Brian: It is in a sense because if you took it away, then…

[(42:24)] Martin: We would be nothing

[(42:26)] Brian: …we would not be here. But then again, it is the same with the electron or the quarks or gravity. There is a long list of things that if you take any of them away, then we would not be here. But it is fundamental. I think it is profoundly important that without it, you would not have complex structures in the universe.

[(42:50)] Martin: Right, that is cool. Wow, unbelievable. I am wondering how deep that might be for the listeners.

[(42:56)] Brian: It is the deepest question. I have a friend I work with a lot, Jeff Forshaw at Manchester. I wrote papers and books with him. He always says that the most incredible thing is that anything exists at all, right? 

[(43:09)] Martin: Yeah. 

[(43:10)] Brian: The great unanswered question in which we started with really, is why does the universe exist at all?

[(43:20)] Jax: It is so complex as well. Like even when you were talking about the speed of light, right? I am just listening to that and I was like, “Wow. What a handy tool. Thank you very much light for being constant.” Do you know what I mean? 

[(43:33)] Brian: It is remarkable. I mean, it feeds into Einstein’s theory of relativity, which is, it is part of the structure of the universe itself. So space and time, how do they fit together? What the geometry is of the universe?

[(43:46)] Jax: So complex.

[(43:47)] Brian: That is intertwined with this speed of massless things. It is all part of the same construct. 

[(43:54)] Martin: I mean, obviously our assumptions and the discoveries that scientists made are there to be challenged, and they are there to evolve. One thesis may turn into a completely different outcome, revisited ten years later. Could our assumptions be wrong about the Higgs boson particle or about the way we define an electron? How much confidence do we have with this kind of taxonomy that we are using?

[(44:21)] Brian: It is a good question and it is almost certainly the case, that the electron is not the fundamental building block of nature. 

[(44:32)] Brian: Likewise, I suppose that the Higgs in that sense, we strongly suspect there is a deeper layer. You hear about things called String theory.

[(44:44)] Brian: Experimentally, which is all there really is in science, right? I suppose what we are saying is that with the biggest microscope in the world, these things look like point-like objects. We cannot measure any size when it comes to an electron. We can when it comes to a proton which we did in the 60s ultimately. We thought maybe that is a little point-like thing and it was not. It turned out that it is quite a big thing with internal structure because we got a bigger microscope.

[(45:16)] Jax: When you say bigger, can you just give me like some other better word to compare the size of a proton to an electron? You said it is bigger. Talking like a goldfish to a tadpole. What are we saying?

[(45:29)] Brian: In a sense of a proton, because we do not know how big an electron is, I cannot quite answer your question. As far as we can tell it has got no size at all.

[(45:41)] Jax: What?

[(45:43)] Brian: But that is probably not right. That is almost certainly not right. We have an idea called the Planck length which we will get to again if we do black holes. Which is something we can infer is the smallest distance we can talk of with any understanding and that is way way way way way way way way smaller than the proton. But we cannot measure those distances so that is experimental in a way. In particle physics, we have a theory that tells us how the smallest things we can see, as far as we can tell, have got no size. They probably do but how they interact with each other and how they build up the world that we see. But I am sure there is an underlying structure that we have not discovered yet. 

[(46:27)] Martin: Let us just define what people think space is. There are people like Felix Baumgartner going up 300,000. He was up there and what point is he actually in space versus he is somewhere in the stratosphere or within Earth’s gravity. 

[(46:44)] Brian: Space in that sense has got an arbitrary definition. I think it is a hundred kilometers or something.

[(46:52)] Martin: That is what I heard. 

[(46:54)] Brian: Yeah and people say if you go above that, you are an astronaut, you are in space. You are not really. There is no clear definition of what you mean by that because you never escape. If you think about it really technically, really pedantic, the gravitational pull of the Earth falls away as the square of the distance away. You double your distance away and it goes down by a factor of 4. In that sense, you never escape the pull of the Earth completely. I mean, you get into the gravitational influence of other objects, so it becomes negligible. Likewise, with the atmosphere, it just dissolves away tenuously until there is not much of it left as you go up. It is an arbitrary definition, but that is not what we talked about. 

[(47:40)] Jax: At that point, when the gentleman Felix discovered the distance where space is. If I get to that point, do I just start floating?

[(47:49)] Brian: No. The Earth’s gravitational pull is pretty much as strong as it is on the ground. The floating thing is extremely important if we want to talk about it. 

[(48:00)] Martin: Let us do it. Let us do it. 

[(48:04)] Brian: What is happening in the International Space Station where the astronauts are floating, right? That means that by floating you mean if the pen or something. 

[(48:15)] Martin: You let go of it  and it does not move.

[(48:16)] Brian: That is what you mean, is not it? You sat there, you go. It stays where it is. Newton would have said that what is happening is that the… I mean, this is the way you think of an orbit that the space station is falling towards the Earth, but it is moving sufficiently fast in that direction that it keeps missing. So it is constantly falling. The question though is kind of interesting if you think about it. The gravitational pull on the space station in Newton’s language is bigger than the gravitational pull on the astronaut. Because the space station is more massive and Newton says that the more massive you are the stronger the pull of gravity. But Newton also says that if you think about gravity pushing like a force pushing something, it is harder to accelerate something if it is more massive. It is harder to have to push a bus rather than a bike, to accelerate it to ten miles an hour or whatever. Those things cancel out in Newton’s picture. The gravitational pull is pulling everything down and it is pulling on the more massive things more than the less massive things, but it is also harder to accelerate the more massive things than the less massive things. It all cancels out and everything just stays there. 

[(49:31)] Martin: Right.

[(49:31)] Brian: Einstein realized that there is a better explanation for that and it is better in the sense that it is a better theory. Einstein says that the reason that everything just floats is that there are no forces acting on them at all. Now, this is really weird. But what is happening in Einstein’s picture is free fall. So you are falling towards the Earth from one picture. A Free fall is what you call it. There is a fancy name, which is an inertial frame of reference. It means no forces are acting. So in free fall, if I let go of something, why does it stay there? Because there are no forces acting. So nothing goes anywhere. Free fall is the natural state of things. Einstein says it is actually on the surface of the Earth, standing on the surface of the Earth is where something is happening to you. You are not in free fall anymore. Some things got in the way if you free fall through space and time actually through space, some things are in the way to the surface of the Earth. The Earth is exerting a force on you stopping you, falling in your nice natural way of things. That force is accelerating you because it does. Because the force is accelerated. So what is happening in Einstein’s picture is that you sat on your chair now and the reason you think you have got weight is because you are flying upwards. You are being accelerated upwards at 9.8 meters per second squared and you are being pressed into your chair. It is just in the same way that if you accelerate in a car, you get pressed into the seat. It is exactly the same thing in Einstein’s picture. And you say well how is all this working? Ultimately, what Einstein says is that there is a fabric of the universe which is called space-time. We always call it the fabric of the universe and it is distorted by the presence of matter and energy. So it curves and everything on its natural way of things will fall, will just take nice straight lines through that curved space. That is the natural way of things. If you are taking an actual straight line which the astronauts and the space station are. Then everything is fine and there are no forces. There is nothing and everything just floats and it is all very nice. If you disrupt that straight line because of something is in the way, then you feel a force. That is the fundamental basis of Einstein’s theory of gravity, completely different from Newton’s. I always say, you know Newton said, the apple and it is apocryphal but the apple fell on his head from the tree. He would have said well because there is a force on the apple, which is the Earth’s gravitational force, it pulls the apple down. Well actually, it pulls them together. The force on both of them pulls them together. Einstein said, “No, Newton accelerated up to headbutt the apple.” That is basically a completely different way of looking at it.

[(52:32)] Martin: I am going to challenge something here. Maybe I am going crazy because I have read about this and I am still confused. Getting back to the term free fall, right? Why could it not have been… In the idea of using your apple pen, if there are no forces at work. It is just constant. It is not doing anything. Why could it not have been free climb rather than free fall? Why do we have to fall at all?

[(52:56)] Brian: It is free fall in the sense that space is a language. It is the sense that it looks from our perspective, if I drop that pen then it falls to the ground. 

[(53:05)] Martin: Yeah. 

[(53:06)] Brian: What is interesting from Einstein’s perspective is actually what is happening is that now when the pen fall, when I let go of it, it is now on a straight line through space-time which is great. Nothing is happening but the ground is coming up. The ground comes up to hit it and then you have all sorts of conceptual problems about why is…  If the ground is coming, accelerating in London and also in Sydney, then why is not the Earth getting bigger?

[(53:35)] Martin: I was going to say that, yeah.

[(53:37)] Brian: That really is harder to picture but it has to do with this distortion of space-time. It is the warping of space and time by the presence of the Earth that is causing these straight-line trajectories to look unusual from our perspective.

[(53:53)] Martin: I mean we got so many more questions but let us deal with the black hole. 

[(53:57)] Jax: We have been dancing around.

[(53:58)] Martin: We have been flirting with the idea. So why does the theory not working and start with, if you could for everyone, at a kind of general definition of a black hole?

[(54:06)] Brian: A black hole, I mean, the way that they are made in nature which is a good place to start, the ones that we observe in the sky by the collapse of some of the smaller ones, the collapse of stars, very massive stars. You got a very very massive star. Let us say thirty to forty times the mass of the Sun. Those are really big and there are plenty of those around in the universe. They hold themselves up against the pull of their own gravity by burning nuclear fuel which releases energy, which then creates pressure that holds them up. They kind of have an equilibrium. They are trying to collapse and they are hot, and everything is moving around, they hold up. But ultimately they will run out of nuclear fuel because of their finite size and so they stopped doing that and they collapse. For these very massive things, tens of times the mass of the Sun, nothing can stop them from collapsing. So they get denser and denser and denser. They collapse, they collapse, they collapse. For every object, if you think about the pull of gravity on the surface of the Earth, then you can build a rocket and you can escape. You have to go at a certain speed whatever is 17,000 miles an hour. I cannot remember exactly what it is that you need to get out. If you crush the Earth down and make it denser. Then you get closer and closer to all these mass and so the gravitational pull of the surface gets bigger. So you keep crushing it. Imagine you get to a point where you would have to travel at the speed of light to get off. It is called the Schwarzschild radius of the Earth. For the Earth, it is about, if I remember rightly, about 1.4 millimeters or something like that. I know what it is for the sun. For the sun, it is three kilometers. So if you squash the Sun, down into a ball that was three kilometers, then even light could not escape from the surface. That collapse is what makes a black hole. So it is when something collapses and collapses and collapses. Nothing can stop it and it goes inside its Schwarzschild radius. There is a region of space where you would have to go faster than light to get out. 

[(56:19)] Jax: So there is space inside that little ball.

[(56:27)] Brian: In Einstein theory, absolutely yes. So the space and essentially the thing collapses out of existence and so you just got this kind of really heavily distorted space inside and this singularity that we do not know about. Somewhere, which is in a very real sense, the end of time actually in there. You get this complete distortion of space and time, so that is a black hole. It is defined by this region which we call the Event Horizon, which we just got this,  everyone knows the word. It is basically the region of space where if you go in you are fine according to general relativity. You would be in there, but you cannot get out and more than that. Not only can you not get out but you are going to the end of time. And actually for black holes that are quite big even like the one at the center of the Milky Way galaxy. These things are millions of times the mass of the Sun. The end of time is minutes away from you, even in the biggest ones. So you can go in but the time is going to end for you. You go into the singularity if you like, but it is better to say you are going to the end of time. So that is a black hole. 

[(57:38)] Jax: Can you see every event? What is it? Can you see every event that has happened in that space ever? As you go in obviously, you cannot come out but you are going in and you see everything, right? 

[(57:52)] Brian: Yeah. It is actually a misnomer. People often say it but it is not right. I mean people have said it, loads of people say it. But it is wrong actually. When you look at it. One way to think about it because you are in there for quite a short time before your time ends. You do not receive anything. 

[(58:10)] Martin: There is no epiphany. 

[(58:12)] Brian: No, so that is kind of interesting. It is cool. It is a really fascinating idea; these completely collapsed stars, the supermassive black holes billions of times the mass of the Sun at the center of galaxies. It is all fascinating. But the reason, they are really interesting is because in the 1970s Stephen Hawking noticed that they are not… People say black holes are not completely black so you might think in black holes nothing escapes. So that is it. If you go in, you are gone, and it just stays there forever because nothing gets out. He found that they do actually radiate. They have a temperature. They behave like anything else and the radiation comes off them. It is called Hawking radiation and that ultimately makes them evaporate away in the very far future, in billions of billions of times the current age of the universe. These things last forever almost but not quite. It looks like they evaporate and that caused absolute havoc in physics. The reason it caused havoc is because people were worried about what happens when you throw something in. What happens to the information? So if I get this book, Stephen’s textbook, and throw it into the black hole. Does that information get destroyed or does it come back into the universe in the Hawking radiation eventually? Now, it is a fundamental part of all of science, I would say, physics certainly. Information is not destroyed. If you know and this is kind of an act of belief almost. It is foundational. If you know everything about the universe at some point, some time. You know everything that is moving around and everything that is in there. Then you can predict what is going to happen in the future and you could predict what had happened in the past. Information is not destroyed but it looked to many people like black holes destroy information. But the question was when this thing’s evaporated away, what has happened to all the stuff that went in? 

[(60:21)] Jax: Then you said time ends. Like you said.

[(60:25)] Brian: Yeah in general relativity, it is the end of time in the middle. So there is something funny going on basically in black holes. This argument went on for fifty years. That is probably still going on but it is pretty much been solved now most people think the answer. But basically, the information comes out in the Hawking radiation, but in order to do that we had to completely destroy, I would say, our notion of what space and time is. This is when you start. You have probably heard it when people say the universe is a hologram. 

[(60:60)] Jax: Yeah.

[(61:01)] Brian: You may have heard that stuff. It is because the way that the information appears to get out of the black hole in the Hawking radiation, seems to require a non-locality in the universe. It seems to say that in some

sense the interior of the black hole might be also the far distant Hawking radiation, that has gone out into the universe. Hundreds of billions of light-years away, probably by the time the black hole evaporates. But in some sense, it seems to be the same place. The other weird thing which is easier to say perhaps is that if information goes into that black hole and then comes out again, eventually. It is stored somewhere, right? 

[(61:42)] Jax: It has to.

[(61:45)] Brian: It is like a hard disk. Black holes are the ultimate hard drives, right? They can store more information than anything else in the universe. But if you say how much information can I fit in a black hole? What is it going to be proportional to? Well, you think if information is going to fit in the library, it must be something to do with the volume of the library. How many books can I get in it? 

[(62:09)] Jax: There must be a capacity in the library? 

[(62:10)] Brian: The capacity of the library. How much can I fit in? With a black hole, the amount of information, you can store there is proportional to its surface area and not its volume. 

[(62:23)] Martin: Right. 

[(62:24)] Brian: So it is the surface area of the Event Horizon. It seems that in some sense, the maximum amount of information you can fit any area of space is nothing to do with the volume. It has to do with the surface area only and that is the holographic thing. That saying, well that is like a hologram. It is saying that these things seem to be telling us that the universe is really in a sense, got lesser dimensions. It is somehow that everything is happening on a surface. What we perceive in the interior, the interior does not really exist in the sense that the hologram does not exist. It is all flat. All the information on some surface and that seems to be what they are telling us.

[(63:11)] Jax: I no longer want to travel through a black hole if I can just get all the information on the surface. Right? If the volume is not important. 

[(63:19)] Brian: Yeah, and then you start saying what happens then? Because as I said before, although it is probably too [inaudible] When I talked about Einstein earlier, I was talking about free fall and the fact that when you are falling freely then nothing is happening to you. In Einstein’s description of a black hole, the Event Horizon is nothing. It is not there in the theory of relativity. You just fall through it. You do not notice a very big black hole in particular. You do not notice anything. It is part of the fundamental structure of the theory because you are just floating. You might as well be standing still. I mean, just in a deep sense, you just float. Then we have also got this quantum mechanics and the stuff that Stephen had originally calculated which is saying somehow, that information is stored on the boundary of the black hole, in the Event Horizon but Event Horizon is not there in Einstein’s theory. So, what is it? What what are we saying? This led to probably the deepest insights into fundamental physics in the last few decades. Trying to just reconcile those two things and it is all very simple questions about what happens if you throw something into a black hole. Does it come out? How does it get out? How is the information encoded? The last thing I will say which is the best thing of all and I have no understanding of what this means. So this year and last year some of the… You might say, well if the information comes out in the Hawking radiation, how is it encoded? How am I going to measure it? How can I reconstruct what went in? It turns out that the people who seem to have worked that out are quantum computer engineers and not physicists. It seems that the information is encoded in a way that we use when we are building quantum computers to make error correction work in the memory of quantum computers. So there is some deep link between quantum computing and black holes. 

[(65:24)] Jax: That is mind-blowing. That is incredible.

[(65:28)] Brian: Space and time quantum mechanics, all mixed up in these bizarre objects, and that is why they are so fascinating.

[(65:35)] Martin: It is fascinating. When you were describing the black hole and the way it contracts. For some reason, I kept thinking of solid-state drives. The chip, that is it is contracted to something so dense. 

[(65:49)] Brian: Solid-state drive is a good example. You could say, well what will happen if I kept putting information in? If I kept trying to store more and more information in my solid-state drive. How much can I get in? And also if you keep doing it and keep putting stuff in and making smaller and smaller things, ultimately what happens is it collapses into a black hole. It collapses into a black hole in such a way that the maximum amount of information is just the area of its Event Horizon. 

[(66:16)] Martin: You said something earlier, with your example of a black hole with the size of four times the Sun. You said it will collapse at some point [inaudible] is the equilibrium between the two. So I assume that at some point the sun will collapse. 

[(66:31)] Brian: Yeah, but it is not massive enough. So there is something that will stop that. So gravity is squashing it down. There is a thing called… We actually spoke about it earlier, which is the fact that electrons do not like to be close to each other. I said that plays a role in getting solid. So what happens when the sun collapses, is that those electrons get pushed closer and closer together and they collapse. They move around faster and faster, trying to avoid each other and that makes a pressure which can hold it up. It is called electron degeneracy pressure. So for anything less than 1.4 times the mass of the Sun. It is called the Chandrasekhar limit.

[(67:19)] Jax: The Chandrasekhar limit.

[(67:21)] Brian: That is after the physicist Chandrasekhar. He worked it out. Then that pressure can hold it up. It becomes what is called a white dwarf star. So a white dwarf star is held up by that. There is another one if you are going to get more mass and it goes again. Basically, what happens is the electrons have to move faster than light to hold it and they cannot so it collapses again. The protons turn into neutrons and you get a neutron star and that is held up by the same thing. But for neutrons, they are like stars the size of cities. Those things are more massive than the Sun at ten kilometers across or something like that held up by the neutrons. But if you do more and more and more, if the neutrons cannot hold it up, that is when you go through the Schwarzschild radius. It gets so small that you go through the Event Horizon. The Event Horizon comes out essentially.

[(68:15)] Jax: But that is not happening to our Sun?

[(68:17)] Brian: So they burn hydrogen into helium. So what the sun is doing now is called the main sequence star. When they run out of hydrogen then their core is basically helium. So the thing starts to collapse and then it heats up to the level where the helium can start to stick together to form carbon and oxygen. That is where the carbon and oxygen of the universe come from. That regenerates the star for a while and it gets bright and hot and then it will run out of that and the big ones can collapse again. They can build things all the way up to iron, in fact, in their cores. In the process, they swell up to become red giant stars. They become enormous in that phase. The sun will probably engulf the Earth in that phase. It might not be quite that sometimes because it loses some mass. The Earth drifts out a bit, but roughly speaking, it will certainly engulf Mercury and Venus and come out to what will approach the orbit of the Earth in size in that final phase of its life before ultimately it will collapse. But the Sun is not that massive. 

[(69:29)] Jax: When do you envisage that happening? 

[(69:31)] Brian: We know it is about… I mean it starts to change in a few billion years. Ultimately, it has got about five billion years left or so. What happens is the outer layers drift away and it becomes a white dwarf and something called a planetary nebula.

[(69:50)] Martin: If we have just a couple more definitions because I think these words are not in popular culture. Perhaps you would like to frame first what a supernova is, not a champagne supernova, just a supernova. 

[(70:01)] Brian: Supernova, there are some different types but basically it is when the star reaches the end of its life. It runs out of fuel and collapses.

[(70:09)] Martin: Right.

[(70:10)] Brian: This collapse is what you will get even when you form a black hole. It does not just collapse and go. It kind of bounces and it is chaotic. You emit loads of energy. So it is basically an explosion that releases a tremendous amount of energy. There are different types. The other one, the one we use actually. I said that some Supernovas we know how bright they actually are. They are called type 1A supernovae and they are different.  They are usually something like a white neutron star or a white dwarf. It will be a white dwarf actually, with a companion star next to it. Remember that the white dwarf has a limit; the Chandrasekhar limit. It cannot be more than 1.4 times the mass of the Sun. Let us say it was 1.39 and it was there and there was a big star going around it. There is stuff falling onto it from the big star so it goes over the limit and then collapses and explodes in a supernova. Because we know the limit, we know the process is always the same. When we see one of these things we can say, “Well, we know how bright you are actually, and we know how bright you look so that allows us to measure the distance to you.” They are so bright that we can see them in galaxies that are hundreds of millions of light-years away. So that is how we measure the distance to galaxies.

[(71:42)] Jax: Brian, when was the last time we saw a supernova? 

[(71:45)] Brian: We see them reasonably regularly and so it would have been last year. We are always looking for them because every time we see one. We may well have seen one this year. Actually, we see because there are so many galaxies out there. So the rate of them is something… A rule of thumb is one per galaxy per century, we tend to say. But of course, we can see hundreds of millions of galaxies so we see a lot of them. Every time we see one of these special ones, the type 1A. We can use that data to refine our measurement of the age of the universe because we can refine our measurement of the expansion of the universe. We are looking for them all the time and we see them all the time. 

[(72:29)] Martin: What are the definitions that might be interesting in popular culture to understand space as we know it? I am going to throw one out there as the one you could possibly answer for us, is an exoplanet. 

[(72:41)] Brian: Exoplanets, if you go back to the early 1990s, also the 1980s. Better synthesizers, but the keyboards we talk about that. It is not bad but with more characters. Anyway, we did not know of any planets beyond our solar system because we have not detected them. So even if we thought, well we cannot be special. We did not know. Then in the early 1990s, we started being able to detect planets and now we have detected well over 3,000. I cannot remember the exact number. We have got missions up there like the Kepler telescope that are just trying to detect planets, so thousands of them. Now, the statement is that pretty much every star in the sky will have planets around it, which is remarkable. If you go out on a clear night, it is quite clear now actually. If it is clear tonight, you go out and look at stars. You can imagine that there will be solar systems around everyone.

[(73:36)] Martin: Pretty much. 

[(73:38)] Jax: Yeah.

[(73:37)] Brian: So that allows us to start thinking, do statistics and say, “Well, how many potentially Earth-like planets might there be in the Milky Way galaxy?” The answer is about 20 billion. 

[(73:49)] Martin: We are on to some of the more controversial stuff. 

[(73:51)] Jax: There is an Earth-like there, about 20 billion…

[(73:55)] Brian: Potential earth-like planets. The reason people say potentially is what you mean there is a rocky planet. The right distance from its star possibly if everything is right, to have liquid water on the surface and so on. So we do not know exactly but rocky planets in a nice distance from the star. Perhaps one in ten stars has an Earth-like planet in that sense. 

[(74:18)] Martin: So an exoplanet is something with water on it. Is Earth an exoplanet? Is there a distinction?

[(74:25)] Brian: No. Exo, it just means not in our solar system.

[(74:28)] Martin: Not in our, okay. So what is the definition of a water planet? One that is likely to have water?

[(74:35)] Brian: Well, we call them… We talk about a thing called the habitable zone around a star. Now in the solar system, there are three planets in the habitable zone. There is Venus, Mars, and Earth. Earth is in the middle. Venus is closest to the Sun. Mars is further away. All of those planets that we think had water at one time or another on the surface. They all could have been habitable in that sense. Still, we are looking for life on Mars to this day. 

[(75:00)] Jax: Why are we looking at Venus for a potential place?

[(75:04)] Brian: It had a runaway greenhouse effect. It is now the hottest planet on its surface in the solar system. It is 470 C° or something.

[(75:13)] Jax: Is that predictive in some sense for what we are heading towards?

[(75:16)] Brian: A greenhouse effect?

[(75:17)] Jax: Yes.

[(75:18)] Brian: So we think that Venus probably had oceans. Maybe, a couple of billion years ago, not just after it formed but maybe for quite some time. It is covered in volcanoes and what we think is there was a runaway greenhouse effect that turned it from something that could have supported water to something that now will melt lead. So the greenhouse effect does that.

[(75:43)] Martin: Yeah, climate change. I mean, I just think if there was ever an example. Is there any way to closely examine Venus given those kinds of [inaudible] material?

[(75:56)] Brian: The Russians landed on it. 

[(75:59)] Martin: When did the Russians land on it?

[(76:02)] Brian: In the 80s. The Russians have made, I think at least two successful landings. They did not last very long, but they took pictures. Also, there is a spacecraft, I think it is called the [inaudible]. There are various spacecraft up there and all have been in orbit around Venus. They use radar to map the surface. So we have maps of Venus. We have seen the volcanoes by bouncing radar off them. The thing is it is always shrouded in the cloud though. So you never see anything in optical light. If we take pictures of Venus it is just the cloudy thing. Which we see even in the 50s, I have got these books by people like Patrick Moore. Real astronomers, who used to speculate that there might be life on Venus in the 40s, 30s. It was not until we had radio telescopes that we could see that it was hot. Because again, it is one of those questions. It is a simple question. How do you know? If you have never been there, how do you know? 

[(76:60)] Martin: How do you know? Yeah.

[(77:02)] Brian: But you can see it from what it radiates. If you got a radio telescope, you can see the radiation coming off it and you guess it is hot. 

[(77:08)] Martin: You said there are 20 billion earth-like planets. 

[(77:10)] Jax: Here we go. Here we go. 

[(77:12)] Martin: This is it. 

[(77:12)] Jax: Here we go. All right. It is getting a bit lofty but 20 billion Earth-like planets. Why are we on this one? And surely, there must be another Jax Jones somewhere out there in the universe. 

[(77:26)] Brian: Well, yeah, and that is just in the Milky Way, by the way. Within 20 billion in the Milky Way, there are two trillion galaxies in the observable universe. There is plenty of room, you are right. What is interesting is when you talk to astronomers. Well, we think, we estimate the 20 billion potentially Earth-like planets out there in our galaxy. Surely, there must be life all over the place. I would agree with that. With life, it is a guess because we are not found anywhere, but what we know from the history of life on Earth is that life began pretty much as soon as it could here on Earth. We have good evidence that life was around, let us say 3.8 billion years ago. The Earth is only four and a half billion years old. So pretty much as soon as the Earth had formed and the oceans formed on the earth. You see evidence of life. That might give you a sense that the origin of life on a planet might have been a  high probability given the right conditions just because of what we see on Earth. But this is really important, if you then say, “Well, when did complex life appear?” So not just a single cell.

[(78:36)] Jax: That is the key definition here. 

[(78:37)] Brian: Not just slime but stuff that can you know… animals, plants, and things that can think, and make a podcast, that kind of stuff.

[(78:45)] Jax: Thanks for putting me in the complex category. 

[(78:49)] Brian: The evidence of complex multicellular living things on Earth goes back to let us say, 600 million years or so. Not much further than that. So it is within the last billion. On Earth what happened was that there are single-cell things doing interesting stuff, photosynthesis, and things. Let us say three billion years from the origin of life. Nothing else. Not much going on. Slime for three billion years and only in the last billion half a billion-ish, do you see complex life. It took about a third of the age of the universe on Earth to go from the origin of life to civilization. That is a very long time. You are asking if the star was stable and did not run out of fuel and the orbit of the planet was stable. It did not get hit by too many asteroids and nother planet did get hit during that time. All these things. I think if you start asking for stability on these exoplanets, for billions of years, if that is what it takes typically to go from the origin of life to something that can think. Then there may be very few places indeed where you said…

[(80:15)] Jax: That lowers the odds significantly. 

[(80:17)] Brian: That is a guess. It is an educated guess. That is my view though. And I think most biologists I speak to, tend to take that view. Most not all but most. Biologists are much more pessimistic, I find, when it comes to complex life than astronomers because they know what a tortuous path it was from the origin of life to us. If you think of the eukaryotic cell, which is what we are made of, and every complex living thing on the planet is made of. Every plant, every blade of grass, every insect. Everything is made of it these eukaryotic cells. And the other ones are called prokaryotes which are bacteria and things like that. The eukaryotes, it looks like those things evolved once on this planet and it looks like what happened is one type of

a primitive cell called a bacteria in this case, got inside another kind of cell called archaea, which is still around now; single-cell. It got inside and it did not die and somehow managed to multiply like that. It looks like that happen once and it looks like that is the origin of all complex life on Earth.

[(81:28)] Martin: Fascinating.

[(81:30)] Jax: That is amazing. 

[(81:32)] Brian: When you see things like that, which probably happened about what, 2 billion years ago or something in some primordial ocean. You think well, what are the chances? When you start seeing the things that had to happen to make us, you start to think that this place may be extremely special. You can make the argument and I do actually. I think it is very important politically as well that this could be the only planet in our galaxy currently that has anything on it that can think. And your first question, you talked about meaning in the universe. Meaning, what is it? It exists because the universe means something to us. So it would be ridiculous to say. We do not live in a meaningless universe because meaning self-evidently exists because we exist. It is a property of ours, I would argue. It is a property of human brains, a property of thoughts, consciousness. If we are the only planet currently in the Milky Way where brains exist, where conscious thought exists. We are the only place where meaning exists in a galaxy of 400 billion stars. Now that I think is a good working hypothesis. You then ask yourself, should we be treating ourselves and our planet the way that we are? Because we are indescribably valuable. Notwithstanding our physical insignificance. It would be astonishing. Imagine if we decide to press the button tomorrow, nuclear war right? Press the button. The person who does that might wipe out meaning in a galaxy. That is a very real possibility. 

[(83:15)] Martin: Thanks for kicking a football the size of the universe into my goal. I mean, what you are saying is it is the ultimate sacrifice or the ultimate loss. But it is based on the principle that you hold or the opinion you hold that actually, it is an arduous journey that we have traveled to complex life. How well do you think that is informed? In your mind, could evidence actually get to where we are as complex humans? It is not only a couple of billion years but you have got to survive the odds of traffic. They might be called a meteor. It might be a meteor strike, asteroids and whatever.

[(83:55)] Brian: Well, you are right to point it out. We have a sample size of one in the technical jargon, which is Earth. We can say on Earth, that is what happened. We know that we are related to all living things on the planet. We know there is an unbroken chain of life that stretches back 3.8 billion years to something probably around a vent system in a primordial ocean. So we know that. We have not seen anywhere else. It might be that that was unusual. That we were just unlucky. It took a long time on this planet and that is not the way of things or it might be that we are on the lucky side. We just do not know. But all I think, if asked to form a view. In your industry, all you can do is look at the data that you have.

[(84:45)] Martin: Absolutely.

[(84:47)] Brian: We have this data so we will extrapolate from that until we have some more. 

[(84:51)] Martin: So you believe then, let us put it out there. Do you believe that it is probably, quite unlikely in the Milky Way and perhaps beyond, that there is complex life? That we could be pretty damn special. 

[(85:06)] Brian: Yeah. That is my guess. 

[(85:08)] Martin: Yeah. I think that is a really honest answer. But do you, therefore, believe that if we take the word “complex” out, that microbes, other kinds of molecular structures, things that do not necessarily do much thinking but are happily living somewhere else and that is probably in abundance in this universe?

[(85:31)] Brian: That would be my guess again. Just based on the observation that life began pretty much as soon as it could here. Life, I mean it is quite hard to define life actually. It is something that is chemistry. All this is chemistry, but it is a chemistry that can pass the information on. So it can replicate and pass the information on. That seems to have happened here quite early. So that is what I can say. 

[(85:57)] Martin: I think this leads to another important question. Let us just squash this myth. Do you believe that we are going to be visited by a UFO? We are not sure where it is coming from but it definitely does not belong in our orbit?

[(86:14)] Brian: I mean, I would not be surprised. I always say this, because the thing is, like we said, the flip side of this is there are loads of planets out there. And there have been loads of time. This got a name, actually. It is called the Fermi Paradox after someone called Enrico Fermi, a great Italian physicist. He asked this very simple question, which is where are they? Because given the number of planets, given the number of stars, and given the amount of time, that has been in this galaxy for life to emerge. It seems as if, at least a few civilizations should have become interstellar civilizations. 

[(86:51)] Jax: What he did was made the odds even smaller or larger? Sorry because of the nature of a single event. Do you know what I mean?

[(87:01)] Brian: Part of the evidence, part of the great conundrum here is that on one side yes, we have got the history of life on Earth, which says that we took a long time to emerge. As though it looked quite like an unlikely process. On the other side, you have got all this real estate, which we are discovering every day, all these places where life could emerge. If you think about where we could go. What could we become as a civilization? So already we have got what SpaceX is doing. I think today they are launching two Falcon 9 up there, you have got reusable rockets. We are becoming a spacefaring civilization now very quickly. It is not a hundred years ago that the Wright brothers flew for the first time. Sixty years after that, we went to the moon and now we are becoming a true spacefaring civilization. Give us a thousand years, if we do not destroy ourselves or do anything stupid. I am sure we are going to be on Mars. We are going to be on the moon. We are going to be thinking about perhaps taking our first steps out to the stars. Give us a million years, one million from now, if we survive we should be an interstellar civilization. We should be the ones that are going out into the galaxy. You would think that there is nothing in the laws of physics that says you cannot do it. Now one million years, the galaxy has been around for the age of the universe, 13 billion years. It only takes a few civilizations to have evolved a bit ahead of us, a million years. Give it let us say, a billion years. The billion years is still nothing. You get some civilizations that evolved a billion years before us. Why are they not there? Why cannot we see them? 

[(88:52)] Jax: Maybe they finished already.

[(88:54)] Brian: Well, exactly. Then people start saying, “Well, maybe there is a finite life that all civilizations have. Maybe they destroy themselves. Maybe they do not become spacefaring civilizations. It is Elon musk’s argument. When you ask him, why do you want to go to Mars? He says because I do not want the human race to destroy itself. It is his essential argument.

[(89:12)] Jax: He argues that the patterns are almost guaranteed if we stay here?

[(89:20)] Brian: Not to have all our eggs in one basket, right? 

[(89:24)] Martin: He likes to colonise right? I mean today, we colonize another planet because we feel safer in that colony, right?

[(89:31)] Brian: Well, there are two rather than one. It is absolutely fascinating question. It is called the Fermi Paradox because it is a paradox. Knowing nothing else, you accept what we know about the size and scale of the universe or the galaxy. You can find it in the galaxy because the galaxies are a long way away, but what we know is that you would expect. You might expect it to be crawling with civilizations, right? The fact that we do not see any is a paradox and a potential answer to that that makes sense to me is biology. It is just very unlikely that you get complex living things. This is all opinion but it is really interesting to think about it because you can make a very strong argument. It should be like Star Wars, right? It should be crawling with things.

[(90:30)] Martin: We do not want to wait a thousand years or even a million years because I get where that kind of endpoint might be. That the longer we go, we might end up being cowboys and indians in space or Star Wars. This idea that we are living on ships instead, or the idea that we go to create different colonies. I think of the film Passenger and we have got all our plant life in one of the rooms and everything. That is fascinating but what could we get, you think, in your lifetime? We are of similar age. Or our kids’ lifetime from space. What would you hope to get? 

[(91:02)] Brian: I think we will have a permanent presence on the moon pretty soon and Mars within our lifetime. My guess is it is not the SpaceX time scale. I imagine it is more than twenty, thirty, or forty years, but I could be wrong. I mean the key point from an aerospace perspective is reusable rockets. 

[(91:27)] Martin: Yeah.

[(91:28)] Brian: I remember I had the pleasure of speaking to him. I have spoken to all three of those people actually; Elon Musk, Jeff Bezos, and Richard Branson. They are the three leading entrepreneurs I suppose. With Jeff Bezos, he said imagine that we set off. Let us say we are going to fly from London to New York. You fly to New York and you get off the plane in New York and then you blow it up. One use, single-use 747, triple sevens on it. How expensive is that ticket? That is obviously what we have always done. We do not do that anymore, right? We now have low-cost, reliable access to a near-earth orbit. Near-Earth orbit is already industrialized. It is already an extremely lucrative area to do business in the communication satellites, geological satellites that look for raw materials, weather forecast, everything. It is already industrialized. And now it can be that Jeff Bezos, he said an interesting thing, actually. He said if you think about Amazon what I needed to make Amazon was two pieces of infrastructure; the postal service and the internet. Given that an entrepreneur could move in from his garage initially and build one of the world’s largest companies. In space, it will be the same. So now you have the infrastructure in orbit. You have the possibility of refueling satellites on-orbit. With easy access up and down, the entrepreneurs can move in and they will industrialize that. That will then spread to the moon and ultimately in decades, to Mars and onwards. So I think we will all see that in our lifetime. Certainly the routine use of near-earth orbit. I think that is coming in a decade.

[(93:11)] Jax: Is that okay? Can I circle around on that? We talk about global warming a bit in this conversation and that is due to our productivity, where we produce in and take out resources. Is that okay to go to another planet and continuing the same process almost?

[(93:29)] Brian: Yeah. I think that is better, is not it? 

[(93:32)] Jax: Do we just chill? 

[(93:35)] Brian: What would you like to do? You would like to zone the Earth residentially. I would love to do that because this is the best planet we know of anywhere in the universe. Obviously, there is a selection effect. We evolved on it. We are made for it. It is the best place for us, but if you want to do heavy industry ultimately, then who cares? Stick it on Mars. But I mean, if it is just a rock. You can concrete over the thing and turn it into a parking lot. I think I am kind of being facetious. It is a beautiful place. We are not going to wreck it. But then again, as I said earlier that I thought that we bring meaning to the local universe. So that means to me that the rest of the universe is there. I do not have any problem with going and mining asteroids or digging up Mars for raw materials. Why would anyone have a problem with that? The most remarkable thing that exists in the universe that we know of, is us. We have got some concerns with that. We cannot keep thinking that, you know, you hear people sometimes say the world will be better off without us. That is bollocks. 

[(94:42)] Jax: Yeah.

[(94:47)] Brian: The world would not be better off without us. The world would then be like every other world. There were billions of these rocks. What I am arguing is there might be very few with meaning on them. 

[(95:00)] Martin: Totally. Yeah. Absolutely. 

[(95:02)] Jax: I cannot sit on this call talking to the great Brian Cox and not bring up D ream. We were talking about a prior when before we kicked off about your extensive keyboard collections and what keyboard you are using and stuff. I just find it fascinating that you had significant success in music. I get the impression that it still plays a part in what you do today because the shows you are putting on have got big musical production, right? Then you are an acclaimed, incredible physicist. It is like, wow, what makes Brian Cox tick?

[(95:40)] Brian: I did not have lessons or anything. I did not. Growing up, we were not in a musical household. So I got into it [inaudible] to music and it was I remember, because I was born in 1968, so I am a bit older than you. I got into some of the early electronic bands. It is a bit geeky. I was into Kraftwerk and then OMD’s first album [inaudible] box and those things. I like that music and that technology so I formed a band with a friend of mine. In those days you had to build bits of electronic kit. You cannot buy it. I mean, there were no computers, right? You cannot get them. There’s an x 81 or something with… 

[(96:19)] Jax: I remember that.

[(96:21)] Brian: I remember building things with it that. We built a noise gate at school because we had a drum machine and we had an organ. One of those electric organ things. We wanted to make polyphonic triggers like Ultravox do. So we made a noise gate with soldering ions and everything. We triggered it off the hi-hat of the drum machine and then you could put the cord into it and make it trigger. It was all that kind of DIY electronic music. Then I thought I better teach myself out to play something. So I started with a monosynth and just started trying to play keyboards and to this day I have never ad a lesson. So I do not know how to read music or anything. I cannot read chords. Then my dad was in the local pub and Darren Wharton who is a keyboard player from Thin Lizzy was in the pub and he had moved in close to us in Oldham. And so he gave Darren the demo tape that we had made [inaudible] or something which of course, it was not very good. But he remembered when he was putting a band together after Lizzy split up that there is a keyboard player on Oldham and asked me to go and audition. What I could do by that point was program stuff. He needed a programmer as well. So I got in and I joined this band with him. We got a record deal with A&M records. This is the late 80s, loads of money around, at the time. Up in Los Angeles we recorded an album in Joni Mitchell’s house, actually. We met at Joni Mitchell’s house with Larry Klein who is a great bass player who is married to Joni Mitchell at the time. Then I toured with Jimmy Page and Gary Moore in Europe, ultimately. I had this career with a rock band. I left that band because we had a fight literally in a bar in Berlin. I applied to go to university and then during the time I was fine to go to university. I needed a job and I became a sound engineer. A friend of mine, a really good friend of mine got this band that did not have a deal called D ream. He hated it. He hated that kind of music. He was a rock and roll, kind of roadie. He said, well you do it. You just drive around in a car. They have got a dap player and a mic and go to the clubs and set him up and just do it. You will get a 50 quid or whatever. That is it and it will keep you going to go to university. Then D ream got a deal and did not have a keyboard player for some TV show that they were doing.  They said, you can do that. Can you just stand there and play the keyboards? So I signed it. I ended up accidentally joining the D ream while I was at university. 

[(98:55)] Jax: It is so cool. 

[(98:56)] Brian: So that is what happened.

[(98:57)] Jax: Can we bring all those worlds together for you and create basically the most exciting proposition you have ever heard in, that you are about to hear in 2021?

[(99:05)] Martin: Here we go. Here we go. 

[(99:07)] Jax: So can we do the 2021 equivalent of Baz Luhrmann’s Sunscreen, but with Brian Cox, talking about a futurist monologue. I just put some music to it put it into the world. I think that is a knocker if you ask me.

[(99:23)] Brian: Absolutely. I am totally up for that. 

[(99:28)] Jax: That would be so sick. 

[(99:28)] Martin: By the way Brian, that is so great. That is truly a great offer.

[(99:33)] Jax: Dude, it is your birthday. Let us all the people know that it is your birthday. Okay everyone, sing it with me now. Happy birthday to you. I cannot hear anyone. Happy birthday to you. Happy birthday to Martin. Happy birthday to you.

[(99:58)] Martin: Thank you. That was actually really sweet and the harmony was nice as well. That was cute. I was gonna say it is my first time I have heard that today and it will probably be my last. It is on a podcast and it is with my great friend. I am happy. 

[(100:13)] Jax: Listen. I am sad that we are not in the same room right now. For those of you who did not know, we are doing this podcast on Zoom. We are not united in person. It is also kind of gloomy into this meaningful day. Obviously, the best birthday present is that you recorded your podcast today with Brian Cox. What a guy.

[(100:31)] Brian: Awesome. 

[(100:32)] Jax: Which brings us to the thought of the day which is usually where you and I give something that we have been thinking about. I think it is only right that we talk about something that is a special because it is your birthday. But also highly emotional because it is the anniversary of your father’s burial, his funeral today. 

[(100:52)] Martin: Yeah. 

[(100:54)] Jax: Today of all days it is today. You guys, Martin asked me to prepare a song. There is a song that means a lot to him and his dad. I have gone away and learned it. It is Cat Stevens, Father and Son. Why is this something special to you bro? 

[(101:09)] Martin: Well, one of the things that connect me to my father’s memories is music. He introduced me to a broad range of music and I credit him with my desire to listen to different genres. But in particular, Cat Stevens is a favorite because it was my father’s favorite. I grew up listening to his songs and in particular, Father and Son. When I hear it, it just reminds me of my father and it is impossible to not draw references to the relationship between the Father and Son.

[(101:40)] Jax: When you came up with the idea of performing it as a tribute to your dad, which is what we are about to do guys. Martin is about to make his first public singing performance.

[(101:47)] Martin: In years. 

[(101:49)] Jax: I was up learning this record this morning at 5:00 AM. 

[(101:53)] Brian: I am so appreciative.

[(101:56)] Jax: Well, let us do it, man.

[(101:59)] Brian: Let us do it. Let us pay tribute to your dad. 

[(102:01)] Martin: Wonderful.

[singing] 

[(102:15)] Martin: It is not time to make a change just relax

Take it easy

You’re still young

That’s your fault

There’s so much you have to know

Find a girl, settle down

If you want you can marry

Look at me, I am old but I’m happy

I was once like you are now 

And I know that it’s not easy 

To be calm when you’ve found

Something going on, 

But take your time, think a lot

Think of everything you’ve got

For you will still be here tomorrow

But your dreams may not 

How can I try to explain?

When I do he turns away again

It’s always been the same, same old story.

From the moment I could talk

I was ordered to listen

Now there’s a way

And I know that I have to go away

I know I have to go

[(103:52)] Martin: Hey, thanks for listening to the Jax Jones and Martin Warner show. We value your feedback so please leave comments below or head to our website https://jaxandmartinshow.com/ to get in touch with us. There you will also find a ton of stuff about Professor Brian Cox, his book recommendations, the books he has written, his live shows, and much more about space. We videoed all of this as well, so head to our YouTube for that. Do not forget to like and subscribe, wherever you are listening to this podcast. We will see you next time. Love you.