The Short Happy Life of the Brown Oxford (collection)

Transcription

SIR PAUL NURSE: I thought it was an advert for a washing machine, and we were going to have one of these greener than green by-lines to this. Welcome to what I think is one of the great events of the society. The Michael Faraday Lecture. We have got a great speaker tonight, and so I'm going to say a few words about him. Welcome to everybody here and to those of you in the dining room. Although we are at capacity here, I believe we're also at or close to capacity down in the dining room too. So Frank, you are very popular! Already we can tell that. Tonight's talk is entitled The Asymmetric Universe, given by Frank Close, the winner of the 2013 Royal Society Michael Faraday Prize. We won't clap him just yet, it will happen a little later. This prize, very important prize for us, awarded annually for excellence in science communication. It recognises a scientist or engineer whose expertise in communicating scientific ideas in lay terms is exemplary. Recent winners include Professor Jim Al-Khalili, Jocelyn Bell Burnell, and last year Brian Cox. Frank Close is based at the University of Oxford. He gained his PhD at Oxford but didn't spend the rest of his life there, he had a period at Stamford at the linear accelerator, and then at CERN. He became Deputy Chief Science and Head of Physics, and later distinguished at Oakwood in Tennessee. He was head of communications at CERN; I have to say that CERN is pretty good at communications. They are always banging the drum. You have to keep all of those countries interested in spending all that money on magnets, I suppose. (Laughter) Anyway, Frank is obviously known to many of us, a noted particle physicist, with many papers involved in over 200 research papers and a dozen books. He won the British Science Writer Award on three occasions, I cannot say more, Professor Frank Close please come to the podium. (APPLAUSE) PROFESSOR FRANK CLOSE: Thanks, I was amused what you couldn't see on the bottom here when you came up with the washing machine it was "washing MP" (sic) came up. This was from the summer exhibition last year and many of those involved in the LHC put on the expo. Tonight I was going to wear the Higgs Boson shirt but my elder daughter told me I looked like I worked at Homebase! (Laughter) I decided not to do that. The talk could be called Peter Higgs, Life, the Universe and Everything Else. I plan to speak for 42 minutes if that is the case. On Twitter it is The Lopsided Universe, I make an apology, actually the title I'm using is the Un symmetric Universe, I apologise for ruining the English language. Symmetry, balance and harmony, you know it when you see it. There is this belief that somehow if you follow symmetry you will find how nature really works. I don't know if it has to be like that but it seems to work that way. The message I will show first of all is when you see symmetry sometimes there are surprises. But most things in nature are not symmetric even at first sight they might appear to be. This is the west front of Peterborough Cathedral, where I come from. It looks symmetric, mirror symmetric at first sight; if you look behind the front you see there is a tower on one side and no tower on the other side. Just do an experiment straightaway. How many of you feel that you want there to be two towers or no towers but not just one? And how many are happy with it as it is? And how many of the latter group are scientists! That's the trouble with being a Theoretical Physicist, your theories disappear so fast when you put them to experiment test. Thank you to all of those who got the right answer! (Laughter) There you have asymmetry, but the message of this is why? And asymmetry begets asymmetry. The answer to this I know, because I was told as a very young child, that after they had built the first tower they realised if they built the second tower the west front would collapse. So that is true! So that is the reason why you have an asymmetry. The question why did they build a tower on the left, if you like the tower on the north side first, well why not! That could be an answer. Actually this is an example perhaps of where one asymmetry begets another. If you look carefully you will see the shadows inside the arches. Of course the sun is in the south where we are. And so if you build the north tower first you are in the sunshine the whole time. If you build the south tower first you build the second one in the shade. I made that up, but it is an example of following asymmetry might lead you to interesting conclusions. Now symmetry, for the mathematicians, the rather boring but clear definition, if you perform an operation on something and it stays the same it is symmetric. This little ball here, if you rotate it around the image looks the same always. We say it is symmetric under rotation. This ball sitting on the top of a hump is also symmetric under rotation for a brief movement. You know what happens next; it will roll off and won't stay there. We managed to capture it in the brief moment when it did. This is to give me the basic idea, there are two ways that symmetry enters, one is stable and one is unstable. And in the best traditions of the Royal Institution, I now do the demonstration. If you can bring the camera on to this. So this piece of apparatus sits there. It sits happily in the base, there we are! Great. So I put the ball into here and it sits happily in the base, that is an example of complete stable symmetry. But if I now - in the old days you had a lab assistant do the next bit! - if I now turn this over and I put the ball on the top, of course you know what happens, but for a brief moment that is still radially symmetric, it looks the same from all directions. At random it will end up, in this particular case it landed up down here. If I rotate this around, it will look different. So that is an example. If we can go back to the slides of unstable symmetry and stable symmetry, stable symmetry will survive as long as the universe will, unstable symmetry will not. Nature might like symmetry, but the trump card is stability. That is the golden rule. The golden rule is this, if you have unstable symmetry, you will end up with stable un symmetry, that is why I'm using that horrendous word. The point being that the ball that started off completely and radially symmetric drops down to somewhere random, it is like roulette, case by case, you don't know where it will end, but spend all night and it will end up on the average. That is permeating huge amounts in nature, including the Higgs story. I want to show you many examples of this. We will start with Peter Higgs. 2012, before the famous boson was discovered, I was interviewing Peter at the Edinburgh Festival, and I started off by saying it is much harder to be a Theoretical Physicist than Beethoven or Shakespeare. In Beethoven or Shakespeare change a few notes or words you still have a wonderful work of art. Change a couple of symbols in the equations of the Higgs mechanism, and it doesn't work. And the point is, that's what the difficulty of being a Theoretical Physicist is: you can write a beautiful equation, but if nature doesn't do it, it is useless. It is experiments that decide. That is why I was saying that Peter Higgs had a unique feature out of many people who had this idea back in 1964. He alone drew attention to the way to experimentally test the whole idea. There we were before the boson had been discovered. And I said, so in 1964 you were writing equations on a piece of paper and as a result of this we now have a 27km ring of magnets underneath the Swiss countryside, sending protons almost at the speed of light headlong into each other, so when they collide they make intense heat, similar to what the universe itself was like just after the big bang. We have these wonderful cameras that record what happens, with state of the art electronics filling them, the size of battleships. They produce wonderful images you could use as works of art and put on the wall. But these images are telling you what is going on in a profound way in nature. This is not one of the experimental collaborations. It is the number of people in one of the collaborations that happen to come to one of the meetings, and there are four collaborations like this. So the sum total of people working on this as scientists is in the several thousands, not to mention the engineers and technicians that built the machine, the detectors and the infrastructure. Over time, the whole cost is 10 billion euro, I said the result of writing the equations it has cost 10 billion euro. If tomorrow you found a mistake would you tell anybody?! We now know there wasn't a mistake and the boson is for real. But at that stage we didn't know that. Then the boson was discovered the following month. Incidentally, for those of us in the field who watched it happen, it was an incredibly powerful emotional moment. So scribbling equations on a paper, and 50 years later experiments shows one of these great mysteries, that mathematics knows first how nature works. Later on we do an experiment and discover it for ourselves. It is a profound feeling. As the announcement was made and the evidence was shown and became clear, that what we had believed in our hearts for years or even decades was now known to be true forever. A very profound sense came over. And many people were in tears. I wouldn't have been half surprised if at that moment a thunderbolt had come through the CERN auditorium roof and Charlton Heston's voice would have been berating us for trespassing where we shouldn't. It is a profound sense that science; once or twice in a lifetime you know nature and it is a very humbling experience. Before this I had spent quite a time researching this whole 50 years of stuff. And I wrote this book and the Economist very nicely had this comment, "the Noble Committee would be well advised to read Mr Close's book before making their decision". No pressure there. What was interesting was after the boson was discovered, and then there was a lot of discussion around in the media and so forth, there were several people who had some of the ideas and most have a prize awarded to three. How do you select three theorists out of the group and experiments and all of that? I was at a dinner in Imperial College last summertime and Lars Brink, the chair of the Physics Committee asked me, (in an accent) said "what do you think of all this"? I said, well I think actually this is a triumph for engineering. The machine, the detectors and so forth is a triumph for engineering and we have the Queen Elizabeth Prize for Engineering, that will be an analogue of the Noble Prize in merit, and if the creators and constructors of the LHC could be recognised in that, that would be appropriate. The experimental discovery of the boson itself, you have to choose how you identify who will be credited, but I thought the experimental discovery could be recognised with a physics prize, and then I noted Higgs, Englert and Kibble for the prize for chemistry. There was a reason for that. He said (in accent) "if that happens I will nominate you for the peace prize" (Laughter). Which I didn't get, because they didn't get the prize for chemistry, but Rutherford did. I then showed back in 2012, with Peter on the stage, this slide from 1912, Rutherford and the nuclear atom. One's immediate thought is, the point here is to contrast that picture of thousands of experimentalists today with just one guy discovering the nuclear atom in his experiment at Manchester, which is of course one possible way of interpreting this. But the thing that I was astonished with was this: from 2012 back to 1912, exactly a century, it is roughly half of that time that since Peter Higgs and company came up with the idea and being proved to be correct. There is the same span of time from Peter Higgs’ discovery and the nuclear atom itself. It struck me the huge time spans involved, or how recently it is that we understood that atoms are made this way. And the question of what does this Higgs business do, the common parlance is it gives mass to everything. That is not strictly true; most of our mass is locked up in the atomic nucleus. That is nothing at all to do with the Higgs business, as we will see. It gives mass to the fundamental part, the electron, which you find on the outside of an atom. Why is the hydrogen atom the size it is, in part it is driven by the strength of the electrical forces that hold it together. But in sense of scale, why it is that big not this big is proportion to the mass of the electron, which is on the outside. If the mass of the electron was heavier than, the hydrogen would be smaller. If the mass of the electron was smaller, hydrogen would be bigger. If the electron had no mass at all, hydrogen would be infinitely big, it wouldn't exist. The mass of the electron gives the size to hydrogen, it turns out that the masses of the quarks that created the proton in the middle are the things that cause the nucleus to be compact. The compact nuclear atom we have known since 1912 we now know why it has that structure, it is because the fundamental quarks and the electron gained their mass through the electron. That is in part when I side the prize for chemistry, I wasn't actually making a complete joke. Now let's look, however, at the hydrogen atom to see the symmetry, but symmetry with a surprise. It is this, we are held together by electrical forces, the negative charges and the positive charges of electrons and atomic nuclear, attract and build up atoms but overall there is no electrical charge left over. At long range it is gravity that rules. And that's because the negative charged at electron precisely balances the positive charge of the proton. That is the example of the symmetry, why is symmetry with a surprise? If you are an accountant you say it is obvious, you add one, take away one, no big deal. With due respects to one of my daughters, it is easier to be an accountant than Theoretical Physicist, as we shall now see! It is this: if the electron, as far as we know, is one of the basic letters of nature's alphabet, there is nothing smaller than it, if there is a Morse code we have yet to find it. It is made of little things called quark. These quarks carry fractions of electrical charge, and they don't look like that as far as we know! But the up quark and the down quark have charges positive two thirds and negative one third, in units where the proton overall has plus one. So this is the hydrogen atom not to scale. The single electron on the outside is negative, these quarks cluster in three, never two or four but threes. And the fact that on the average each of them has about one third of electrical charge, causes the proton to miraculously counterbalance the electron. Is that an accident? I will take another test here. How many people think that's an accident or is it a clue to something? Who thinks it is a clue to something? Very good! You are winning! How many think they have the answer? Pity, because if you did I would invite you to come out with me afterwards and share it! This is an example of asymmetry which at first time appears positive, negative and positive balancing, it gives you a clue that there is something going on here, and we don't know what it is. In the space of ten minutes I have brought you to a frontier question that we don't know the answer to. The symmetry of electric charges hints that there must be some relation between electrons and quarks. At the moment we have no clue as to what it is. So it is symmetry with a surprise! Of course when it comes to the mass, there is a huge lobsidedness, that the electron only carries one part in 2,000 in the mass, most of the mass is in the middle. And it is very massive in the middle because the little quarks are gripped in a very small region. And the price of them being gripped there to make protons in the nucleus, it turns out there is a lot of energy, which is E=mc2, the big mass of the protons and neutrons is the energy gripping the quarks in the future; it has nothing whatsoever to do with Higgs. You have this massive asymmetry, and it is good, because it is the masses of the nuclei that look them in place, and the sill flighty electrons can what was the around and do chemistry and biology on the outside. That is asymmetry that is useful. It now raised a question, why is it that all electrons are negatively charged and all protons are positively charged. All it seems to care is opposite charges attract the whole things together. Why couldn't we have positively charged electrons and negatively charged proton as it would work just as well. That brings us to the world of antimatter, because positively charged electrons are called positron. If anyone has had a pet scan, it is positrons that are used. Antiprotons are less common around but we can make them at CERN and use them. The basic particles of antimatter have been known for decades, a mathematician, appealing to symmetry in his equations, discovered that the symmetry, the balance of equation, wanted there to be these opposites. And then three or four years later they are discovered. This was another example of how the mass knows. So there you have a beautiful symmetry. Matter and antimatter in perfect symmetrical counterbalance. How many people here are of the Star Trek generation? Fewer, how many people read Dan Brown's Angels and Demons? Please nobody put your hands up! You know when matter and antimatter meet they annihilate into energy. You can imagine them playing the film in reverse, the energy in the first moments of the big bang turning into counterbalanced matter and antimatter. Our best experiments that suggest that is how things were, and yet, today, some billions of years later, that is what the observable universe appears to be. It is a complete lobsidedness. All matter that we are aware of has negatively charged electrons and positively charged protons. The antimatter, if it exists, we have never found it. Whether this is a hint that there is deep down some fundamental difference, some lobsidedness in the basic rules of antimatter rules we don't know. Or whether they are indeed perfectly balanced at the particle level? But it is an example of an unstable symmetry, because they miss some and some are left over, and you will have clusters of matter that happens to be hundreds of millions of light years across and we happen to live in one. And there will be antimatter clusters elsewhere, we don't yet know. This is an example of a lobsidedness necessary for there to be anything at all. Why it is we don't know. At least we have the conditions to have life, we are matter left over. And 150 years ago, Louis Pasteur said, he said it in French! "I can even imagine that the existence and structure of all living creatures is a function of cosmic asymmetry.” He really, I think, was talking about mirror symmetry here. It is interesting again, that is 150 years ago. That is only three times longer than Higgs writing his paper. So here we have the example, you know of the spherical embryo after some years ends up as the famous, apparently symmetric human that Leonardo drew. It is not symmetric. You will see how observant that Leonardo was, the left testicle is lower than the right. Gentlemen, you don't need to check now! If you do, check the mirror image, but it doesn't matter. There is not a total correlation. But this is the, or an external manifestation of a profound internal asymmetry in the bodily organs. For example, this, that the stomach is on the left and the liver on the right. Not for everybody, for about 1 in 20,000 people you have complete what's called situs inversus - all the organs being mirror inverted. As far as human health is concerned, it doesn't really matter, if your organs are all mirror inverted you have exactly the same health characteristics as most people do. With one exception, that you are more likely to suffer problems with surgery! This is not what you think that the surgeon opened up the wrong side, it is actually a bit more subtle than that. I was talking to a surgeon recently on holiday, a man of my generation from Boston, the medical centre in the States. Had he done gall bladder operations, two a day for 30 years. In the order of that time had he done 30,000 operations. On one occasion he operated on somebody with situs inversus, the organ itself is invertus, here is a man who has done it like tying your shoe lace, who now has to do with mirror inverted. You could get a left- handed surgeon to do it, but that is where the surgical problems can happen, it is because everything is mirror inverted. This begs two questions. Why is the heart on the left and not on the right? Why isn't it symmetric in the first place? Well why it is not symmetric in the first place is because at the level of the heart, the heart is doing an asymmetric job. Now I'm way above my pay grade here, I know people are being very polite and not screaming at me here, anyway, the heart has to pump oxygenated blood to the whole of the body, that is a powerful pump needed. The blood that comes back without the oxygen needs to be sent to the lung is by are nearby, only a little pump. The heart has an asymmetric job. Nearby lungs on the one side, the whole body on the other. That is I presume is an evolutionary thing. Why waste energy having the lungs far way. That is an example of asymmetry. When you have a plumbing problem, once you have asymmetry there, putting all the bits and pieces in gives you asymmetry, why it should be this way and not that way overall, I don't know, I don't know if anybody does. It is not true for everybody. It is only one in 20,000 that goes wrong. But when you come down to the level of molecule force life then it gets interesting. Life is built on carbon, and carbon has this wonderful property of having four legs that it likes other atoms and molecule that is it likes to attach themselves to. The example is to have four hydrogens making methane, and they form this structure you see here. That is what you have is all four are the same. Imagine that all four are different. These might be simple molecules or whole chains of molecules, we are focusing on one carbon atom with the tetrahedron coming out. Can you see there are two ways you can do it? Can you have them on the left or the mirror form on the right? An examination of one of these, well milk, or mirror milk to drink, but mirror humans maybe amenoacid, here you have a simple amenoacid, and it can exist in two mirror symmetric forms, held together with forces that do not care between left and right. Yet living things make use only of one of these. Here is another example of complete lobsidedness. Why? I don't know. And I don't know whether anybody has an agreed opinion on this. But it could be another example that at the pure molecular level you have this symmetry, but it is unstable with regard to living things where you have got to reproduce and procreate. If you have got to find a mate whose DNA, if you like, is coloured the same way as yours rather than opposite, it is inefficient in an evolutionary sense. It could be an example of what becomes unable symmetry. Let me move to something, where I know that stable symmetry turning into unstable symmetry is the rule of the game, that is gravity. Gravity, Newton's law says the force of attraction between two masses is proportional to the masses, it is inverted proportional to the distance of the square between them. It doesn't care about direction, all directions pull together the same. So that has the effect that things being pulled together by gravity will form spheres. And here you have an example of a spherical galaxy. A beautiful example of that. But not all galaxies are spherical. You have these beautiful images of spiral galaxies. Now, if this was the only galaxy that you had ever seen, and you were trying to deduce the rule to the law of gravity from this, if the student said this makes it look like gravity acts in a plain, you would probably have to agree and tick the box that you got the answer right. We happen to know that the fundamental law of gravity is spherical and yet here you see something which is almost in plain. This is an example of unstable symmetry turning into stable un symmetry. Why do I say unstable symmetry, that picture is the picture we have taken today, imagine what it will look like 100 million years into the future. All those stars would be collapsing inwards under the force of gravity. And to maintain that spherical structure they have all got to be in just the right place that they keep heading towards each other. That is very unlikely. And they have got to not be disturbed at all by any other galaxies around that might give them a little tweak. At the end of the day it is exceedingly unlike that you maintain that spherical structure forever and you end up with more stable systems. But there is more than that one spiral galaxy in nature. If you go and look at the night sky you see them pointing every which way. And this is the example again of what happens when you go from unstable symmetry to stable un symmetry, the ball can land anywhere. But over enough throw and it will land in all possible places. The memory of the rule is preserved overall. And you see it here also. That if you plotted where all of the spiral galaxies in the universe are orientated, they would be orientated through all three dimensions. The fundamental three dimensional symmetry of gravity is remembered over the whole collection on the average, but on a case by case basis it gets lost. And that is one of the general rules of this. It is a rule that has been known for hundreds of years, Buridan many years ago considered this. He considered a donkey, completely symmetric, precisely between two bunches of carrots, by the symmetry of the situation he argued it is impossible for the donkey to choose the carrots on the right relative to those on left, then it will starve to death. If you are a philosopher that is sort of conclusion can you come to. We laugh, we know it wouldn't happen, but why wouldn't it happen is more interesting? You can say well something would happen to disturb the donkey. But you are introducing something through the back door when you do that. And that is the sort of thing that I imagine perhaps people might have wondered even in the starting demonstration. I was saying that nature will always take the unstable symmetry and turn it into stable un symmetry. And you are going to say, well that's because you didn't put the ball in carefully enough. And I will say, you are probably right, but let's imagine what's called, I mean theorists love doing experiments in the mind which conditioned be tested. Let's imagine we have a perfectly engineered spherical ball on top of a perfectly engineered spherical hump, made of perfectly spherical atoms lined up perfectly on top of each other. The catch is at room temperature, what is temperature? Things moving around. The hotter you are the more violent they are moving, so these atoms are actually moving around, so at random you can't keep them there. OK you say, let's go to absolute zero, where they are all frozen and not moving at all. Now something very profound happens, quantum uncertainty, the one bit of quantum everybody has heard of and none of us understand. But it is the way the universe is. You cannot both localise something and know at the same time what its motion is. It is in principle impossible, even at absolute zero, to have two atoms sitting perfectly on top of each other and being perfectly at rest. They will be moving somewhere at random. And so quantum rules themselves, in principle, will make that ball drop. You cannot preserve, I will get my unstable symmetry, you can't preserve unstable symmetry, the quantum will necessarily force you to the stable situation and the symmetry gets lost. That is, I think, the general rule. I have used words like "quantum" let me say one thing. There is a free app I worked on with the Science Library, A Z of particle physic, if you go to the app store you can find more about what I have been saying things, the names of experiments and the names of great scientists and mini biographies and what the experiments are, go and search that and it will cost you nothing. Get it because your students will ask the questions and you can find out why they got it from. What has this do with Higgs and all of that? It is this: that the electromagnetic force is what we are seeing as a result of that electromagnetic radiation is coming into your eyes off me, and in quantum theory, electromagnetic waves come in particle bundles called photon is and they have no mass at all. In the heart of the sun there is another force at work, it is one turns the photons of hydrogen, the fuel, by a series of ash and radiation into energy. We call this the weak force, because it is very feeble compared to the electromagnetic. It is a good job it is feeble, it is so feeble that the sun is only just manage to go stay alight. That is what has enabled it to be there for five billion years, enabling evolution to happen and us to be here. It is feeble, we now know, because the analogue of the photon, the quantum of the magnetic radiation has an analogue here, the analogue of the weak red nation is called a double boson. It is massive. And we know it is the mass of the W boson that causes the force to be feeble. We know that because the measurements that have been done in CERN and other places over many years show if the W boson's mass was nothing, just like a photon, the strength of that weak force would be the same as the electromagnetic force. In fact there is the hint of a balance between these two forces. Where there is no mass at all these two forces would be the same. The Nobel Prize for that idea was given to Abdus Salam, and Weinberg 20 or 30 years ago, in the real world the W boson is massive, not massless. What is the symmetry and how does it all work and what has it do with Higgs? In truly empty space that means, not just the vacuum that we know, but in truly empty space, and we will see in a minute or two it is not. But this is a theorist's universe. In truly empty space the equations show that a photon would have no mass, which indeed is how it is, and the W boson would have no mass. You have there a beautiful symmetry, but it is an unstable symmetry, it is only true in empty space. And I can give you an example in the real world where the photon does have a mass, or appear to. It is when space isn't empty. If you have a plasma, what plasma is, it doesn't need to concern us but I will show you an example in a moment, not literally! When an electromagnetic wave hits a plasma and goes through a plasma, I plasma, rather than the nucleus and the electromagnets locked for atom, the nucleus is locked but the electrons can flow everywhere like gas. When the electromagnetic waves goes through that funny things happen. The photon acts as if it has mass. That is a phenomenon known in the real universe, have plasma and the photons will appear to have a mass. The simple idea is to say let's suppose the universe is filled with something else, let's call it a Higgs plasma, whatever that is. So that when W bosons propagate through the Higgs plasma they appear to have a mass. Now this is the point when you think is this scientist going crazy and at what point do I stop believing this? Let me show you the ideas behind this, and it is this. So the real world, what happens when electromagnetic waves hits a plasma. The ionosphere, above us is an example of plasma, and those of us of a certain age used to be able to listen to good old fashioned radio and occasionally the following thing would happen, and you would pick up a radio signal from New York. That signal hadn't gone through the curvature of the earth, it had been heading out into space and then it had hit the ionosphere and been reflected back. This is an example of what happens when a low frequency electromagnetic wave hits a plasma. It can't get in, it bounces back. So you hear the New York radio signal, because that is a low frequency electromagnetic wave. But you can still see the stars shining through. They are shining in visible light, which is a high frequency electromagnetic wave. So this is an example of how plasma will happily accept high frequency waves, but not low frequency. Let's just do the one diagram in this talk. The green represents the plasma, the red at the top is a low frequency wave arriving and failing to get in. And below is a high frequent say wave arriving and happily getting through. Now the leap of imagination. Suppose you were a creature that lived inside that plasma. Your experience of electromagnetic waves would be this, you wouldn't know of any low frequency ones. You would only know of high frequency ones. There would be a minimum frequency, it is called the plasma frequency, but there would be a minimum frequency, so here is this creature, living inside the plasma, for centuries and centuries and they build science, and they build quantum theory of these electromagnetic waves with a minimum frequency. And they discover the idea that frequency is proportional to energy. It says in the mass, the plasma creatures think photons have a minimum energy, the only thing with minimum energy is mass, plus MC2, if you have a mass there is a minimum energy, that is the energy you have at rest. So the creature inside the plasma would perceive electromagnetic waves to come in little quantum bundles with mass. Of course we know what's going on. We are sitting outside and saying you were just fooling yourself, really it is the wave propagating along and it hits the plasma and it is the interaction of plasma that does it. That is because we live outside and we can see what is going on. The creature inside the plasma doesn't know that. They will interpret this as a massive photon going through. But this is a very clever creature, because he decides there is a way of experimentally testing this. And that is this. The plasma if you hit it with the right frequency, it is like old bath night, you used to be able to get in the bath and see the water resonate up and down with you. If you hit the plasma with just the right frequency of energy the whole plasma will recoil and oscillate. A plasma wave, which in quantum theory acts like a particle called a plasmon. And that is all for real. That has been well known. And that is the idea that Higgs and friends then picked up on. The vacuum that we know is not empty, let us suppose it is filled with a Higgs plasma. We now know that is true, because if you hit it with just the right frequency, you can excite the Higgs plasma wave and in particle physics that becomes a particle, or the Higgs Boson. We are creatures that live inside the weird plasma wave marks we know it, and we excited it and bound the boson that was in there. The W boson we interpret as having a mass is because it is affected by this plasma. It is completely analogous, except there are people saying, just a second, I was told that the ether disappeared some way back in Einstein's time and this guy has reinvented it. Yes and no, this is why what these people did is clever, and to show that I have not made this up, this is Peter Higgs' paper in 1964, and in the red box, "they phenomenon, which we call the Higgs mechanism, is just the relativistic analogue of the plasmon," the plasmon I originally gave you was done by Phil Anderson in 1962, two years before Higgs and Kibble and others did their work. What they did was show how to take the idea and make it satisfy relativity. That was the key feature. But the basic idea that when you have a "stuff", plasma, call it what you will, electromagnetic wave, propagating through, if they interact with the stuff will appear to be carrying mass, that is the basic idea behind this. It is the basic idea but how does it apply to the real world. Because in the real world W bosons have mass, but photons don't. Now Higgs, Englert and Brout, who died a few years ago. Independently in 1964 discover the trick of giving mass to things, if you imagine this plasma stuff is there. It was three years later that Tom Kibble, from Imperial College, showed how to take this basic idea and make it work in the real universe. These guy who is share the Nobel Prize this year discovered how to give mass to things, Tom Kibble showed though keep the photon massless. For me that was why I included Kibble with Higgs Englert and Higgs. I think the prize committee were right, by giving it only to Higgs and Higgs, Englert, they were implicitly implying that Brout who did the work was being recognised by the omission of the third person, if so that was quite right. So to conclude, because of Higgs Englert, we know why the W boson is mass, yes because the W boson is massive, we know why the force that keeps the sun burning is very feeble, and that the sun has lasted for five billion years therefore, enabling evolution to happen. If the W boson had been massless the sun would have burnt out within a million years and we wouldn't be here. This is not just arcane, it is relevant to things. What we don't know. It is all very well saying these particles with mass, why the protons should be lighter than the neutron is a mystery. It is very important that it is. Because the proton is positively charged and is the seed for the hydrogen atom. If the neutron was lighter there would be nothing there to grip things. And if you asked a student would you expect the neutron to be lighter than the proton or the other way round, they would say the proton is heavier because it is the energy. It is not like that, nature is the other way round. We don't know why. What we do know, as I said at the start, is why Rutherford's atom has the structure it does. The mass of the electron gives the size, the mass of the quarks gives the compact centre. 100 years after Rutherford's nuclear atom was discovered, Higgs Englert have found the explanation of why the structure is there, which is why I nominated them for chemistry. So to draw the analogy to end with, the Higgs field I say is like the ocean, if it was completely placid you would not know that it was there. But if you put the right amount of energy in, waves started to appear and you would begin to see the ocean at work. And the Higgs field, when things interact with it they gain mass and give rise to structures like starfish and sandcastles and maybe future scientists. So that's the end of The Lobsided Universe. Thank you. Let me leave this up on the screen while you are asking question, that the next thing happening is Atom in March, anybody within the vicinity of that, the first science and technology festival in the heart of where the British and international physics and science labs are is going to be taking place. If you are within reach please check it out. There are some people in the audience who will be appearing at it, they want somebody to be there. Thank you. SIR PAUL NURSE: Thank you very much. We have time for questions. Now there are two microphones that are going to circulate and you need, if you want to ask a question, to put your hand up, wave it, we have got a question over here, and then when you have the microphone stand up please and ask your question. Try to be brief with it so we can get a number of questions. Over there please. FLOOR: Thank you very much, such an interesting lecture. Please excuse my ignorance if this question doesn't make much sense, but from your lecture are you telling us does nothing exist? So is there such a thing as vacuum based on now our discovery of the Higgs particle. PROFESSOR FRANK CLOSE: The brief answer is a vacuum is not empty. Even apart from being filled with the Higgs field, whatever it is, it is filled with gravitational fields, electromagnetic fields and in quantum mechanics it is bubbling in and out of particles all the time. The vacuum is a medium and can change its structure it is an interesting medium, not totally empty. SIR PAUL NURSE: Hands please, right at the back, on the left. FLOOR: Does that connect with dark energy or dark matter or anything like that? PROFESSOR FRANK CLOSE: Very interesting question, it wasn't planted, I thought somebody might ask that so...that is what we know about dark matter! We know that there is more stuff around than shine, because the way that the galaxies behave shows us much more gravitational tug that we could otherwise account for. There appears to be either something fundamentally flawed in our understanding of Newton's law, which one cannot totally eliminate that in my opinion. There are people who persevered with that line. Or that there is a lot of stuff which doesn't shine in any electromagnetic wavelength but is manifesting itself by the gravity. We call it dark matter for that reason. It is possible you could get two for the price of one. One thing I didn't say and I thought some chemists here might raise is, is there is an asymmetry in the left and right in the weak force, nature is a weak left hander. Neutrines go one way and not the other. The neutrinos we know that are lightweight things maybe there are massive right handed verges of them we haven't yet found. That would be another example of a massive unsymmetry, we have seen this bit and those things are waiting to be found. If they are found then they indeed could be things with the right property to build up the dark matter. Because neutrino could be dark matter but for one thing, they are light and flit around quickly, the modelling that cosmologists do of galactic structures appear to want massive neutral things rather than lightweight neutral things. The possibility that all of these things could fall into place is exciting. If that is the case we will hopefully find examples of these dark particles at CERN when it starts up again next year. SIR PAUL NURSE: We all want to know what is the next answer you have on your computer! PROFESSOR FRANK CLOSE: That is in case what detailed physicists wanted to know what had had to do with the Higgs mechanism. FLOOR: It is worth developing the theme a little bit that you mentioned the weak force violates parity, it makes an absolute distinction between right and left handed spin polarised particles at various interactions. It is just worth mentioning that the weak interaction infiltrates to a tiny extent into all electromagnetic processes. It infiltrates into the everyday world. This is something that came out of the, you know, the unification of the weak and the electromagnetic interaction, and that infiltration, it generate as very tiny energy difference between left and right handed ciral molecules like amenoacid, and Abdus Salam in the last few years of his life got very interested in that. He thought perhaps he discovered that the secret of life, why we are all made of amenoacids and blah blah, so a huge industry has developed over several decades over trying to show this parity violation and lifting of the degeneracy is why we have homochirality, it is a lovely idea but there is no experimental evidence for it at all so far. There is no question it exist, you can compute it to within an order of magnitude, but it is very tiny. There are now many more mundane mechanisms which can show how you can get a complete excess of one hand over the other with chiral molecule, that just develops your theme a little bit. PROFESSOR FRANK CLOSE: I was going to ask you has the huge industry succeeded yet? FLOOR: No, they compute it quite accurately, but there is no experimental evidence. PROFESSOR FRANK CLOSE: Let me ask the question back to people in the audience, I'm a bit beyond my pay grade here, I think the following thing is certainly true that the energy difference between the left hand and right handed forms is triflingly small on the scale of room temperature, I always feel it would be completely washed out. It is an interesting thing if you did a precision experiment but washed out in reality. But the question isn't that these things don't exist, L and R do exist, it is just that life only makes use of one of them. And that is the issue to me, why doesn't life, why does only one of them procreate? FLOOR: It is because, once one gets started it takes over, it could have been in the early days there were both, there was life based on both left and right amenoacid, but once gets going it takes over, and life has to be based on homochiral, it is like engineering, once you establish a convention of left hand bolts you have to have right handed nuts to go on it. It is like looking at a glass of milk, it is not good to drink because it is the wrong handedness your enzymes won't touch it. PROFESSOR FRANK CLOSE: I'm feeling like a right handed nut, it is an example of what I'm saying, a light dominance becomes an unstable symmetry, which becomes a stable un symmetry. FLOOR: You were talking about how the Higgs field would stop the longer wavelengths of the W boson from propagating through it, but the W boson is of course related to the Z boson and gamma and everything, but I was wondering how the Higgs field and gravity might interact and if they do and if we know how and any research is being done into it. PROFESSOR FRANK CLOSE: I will, I should have held my party card which says "I don't do gravity"! The understanding of gravity is very tricky and I'm very happy as a particle physicist I'm able to ignore it in practice. Because although gravity is very powerful when it is acting on mega things like the size of the earth, at the level of individual atoms it is so triflingly small we can neglect it. I hope it got me out of the second part of your question. It is a good question, why is it that the Higgs field affects W bosons and Z bosons and not photons. We don't know. Tom Kibble showed how you can create the mathematical description with those properties, but why it is those properties and not other properties, they are, if you like, put in by hand. And indeed, why is it that the weak interaction is left handed, whereas everything else doesn't care. We put that in by hand. And to my mind, to me the two immediate questions that are left hanging after all of this is why are weaker interactions intrinsically left handed and why do the pattern of masses turn out as they are. If the proton was heavier than the neutron we wouldn't be here. But we put that in by hand. So I think we have found the in principle way it all works, but the details of it that is what makes science exciting, that is what future generations and maybe you and your colleagues have chance to answer. I hope I'm around here to see the answers. At the moment it is open. SIR PAUL NURSE: There is somebody but I can't see them. OK. Over there, there is one over here somewhere. FLOOR: A bit of a meta physical one if it may be permitted. I was struck across your talk you posed a number of unanswered "why" questions, I wonder if you would be able to explain why it is meaningful to ask why for instance a sub atomic particle has one property and not another. Must there always be a reason, is the universe not allowed to have properties that are perhaps just arbitrary and irreducible? PROFESSOR FRANK CLOSE: The last question is one, if I had another ten minutes, I threw some slides away. But one of the slides, well, maybe this example we have here, that snowflakes, let me just jump a second, when you melt snow you get a nice bowl of water and you can look at the service of the water and it is rotating and symmetric, then you freeze it and you get a snowflake. Maybe the snowflake is six fold pointing at 10.00 or 1.00 or some other angle. It is possible to draw an analogising’s that there was some sort of meta universe around before the big bang, whatever those words mean, and when it sort of froze is froze and made the snowflake this way, which is the one we happen to be in. And maybe there are other freezings, other ways, which have particles with different properties, that is one possible further example that actually our universe, in a sense, is another stable, un symmetry, and that on the average the true symmetry is averaged out between our universe and lots of others. But you read a lot about these things, Valerie is here, the New Scientist love these sorts of things, whether they are science or not is a question which I find actually quite difficult coming to terms with. If you could do an experiment to test whether there are other universes out there, with different properties, then in a sense by definition it is part of our universe. If it is another universe you can't test it experimentally. Where I came in at the start it is experiment that decides. Can you have wonderful array, but if experiment cannot decide in principle it might not even be science. SIR PAUL NURSE: I was going to ask you how you define science, but I guess that is where you would go. PROFESSOR FRANK CLOSE: It is a wise thing to say "yes"! SIR PAUL NURSE: I wand say "no" anyway. I think somebody else was asking something in the middle. No? There was one up here? Please? FLOOR: I was going to ask something similar to what was being asked, how much of it would you attribute to the anthropic principle? PROFESSOR FRANK CLOSE: Where is John Barrow, ask him! (Laughter) SIR PAUL NURSE: A bit cowardly! PROFESSOR FRANK CLOSE: I don't know, this is one of these questions which I don't see how to approach it in an experimentally testable way. My mind has gone suitably blank, in a parallel universe I have answered your question and been incredibly impressive but not the universe we're in. If the particles did have different properties we wouldn't be here having the discussion. That is a bit of a cop out. On the other hand that might be how it is. The question which is perhaps nearer to this is are these masses and properties in a sense fundamental and that there is some reason for them that we can find, or are they accidental in the sense like radius of the planets years ago people were want to go explain the planetary orbit, we know they are accidental today, are the planetary objects accidental or is there a fundamental symmetry behind the scenes that will reveal the numbers. I don't know the answer to that at the moment. If the answer to the latter is yes then it is not anthropic we are here because it is being like that. There are biologists and those who worry about these things, I throw my sixpence in. I don't think anyone has shown that if the particle masses were different that you could not have living things. We know certain processes in the universe as we experience would not happen. I don't think that anyone has proved that you couldn't have consciousness with a whole different set of parameter, I don't think anyone understand what is consciousness is. A question I put to an audience like this, what is the minimum number of atoms I need before they know they are there? (Laughter) SIR PAUL NURSE: I'm tempted to stop there actually! So there is one more. We will hear that. FLOOR: John Barrow! I think one thing is worth saying. If one is talking about predictions from the early universe of things that affect life, then because of knowledge that the universe has this quantum complexion we shouldn't expect that they would be completely sharp and specific. They will have a probablistic nature. And if your predictions have that statistical character, then you have to start asking well what's the probability distribution of outcome that is you expect and what do you then compare observation with? And you might think well I will compare it with the prediction of the most probable outcome. If the most probable outcome is one that doesn't allow life to evolve and persist that would not be what you would test your theory against. So if you don't have an understanding of how the existence of life is affected by different possible outcomes of a probabilistic prediction, you will draw the wrong conclusions from it. So it is just a method logical principle, if you don't appreciate there are selection effects that might affect your experiment, you will draw wrong conclusions from it. If you don't appreciate there are selection effects imposed by our existence on some probabilistic collection of outcomes you will draw a wrong conclusion again. The big problem, I guess, is telling which other things that have the probabilistic outcomes. So if you were Kepler in 1600, thought the number of planets in the Solar System was a fundamental law of nature. Now no planetary astrophysicist in their right mind would try to predict the number of planets in the Solar System. It is absurd, like trying to predict the number of cars going past in the next five minutes. It as random outcome. And we don't know whether some of these fundamental numbers of physics may not be random outcomes of one of your very deep processes. That is why it is a good game to play. PROFESSOR FRANK CLOSE: I will say one thing about the anthropic principle, I think there is accident that enables us to be here. The three alpha particle, how is carbon made? The fact that there is a resonance level in carbon, in just the right place, that was what I think Fred Hoyle predicted. It is probably the only time in nuclear physics that somebody predicted the existence of a resonance state, the probability of life to happen. A nuclear physicist to calculate that thing is in just the right of place, it is calculation of a whole lot of things, like the planetary orbits, I would say that it is pretty much an accident. I would say that we are here because of an accident, I don't like that, but that is probably how it is. SIR PAUL NURSE: OK, I am going to top it there, I will thank Frank, what we have heard this evening is the reason why we need the Michael Faraday Lecture. Because what we actually need are scientists who can communicate to the public, it is so important that we are engaged with society and telling the public about science is one of the important ways of engaging. The Michael Faraday Lecture is meant to recognise it, it tells us this is important. But it also tells us with what we have heard tonight why Frank Close is such a worthy winner of the award of this lecture. Because he has given us a very lucid lecture, as we have heard, about a very difficult subject, and he has also made us laugh too. I think combining all that is difficult, we have seen how it is done. We have got a master in science communication here tonight. I just want to thank you and congratulate you on your lecture tonight. (APPLAUSE) Know we have a presentation, but poor as the society is we do manage to put together a scroll. A medal. A very nice medal and a cheque. PROFESSOR FRANK CLOSE: Thank you very much. (APPLAUSE)