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Higgs bosons, quarks, supersymmetric particles & miniature black holes
Into the unknownSomething extremely important is going on today in a giant tunnel beneath the Swiss countryside. But precisely what 'mysteries of the universe' are the scientists at Cern hoping to solve - and does it matter whether or not they succeed? Stuart Jeffries gets to grips with Higgs bosons, quarks, supersymmetric particles and miniature black holes
The universe is increasingly incomprehensible, don't you find? Consider that small part of it taken up by James Bond films. For decades they were satisfyingly stupid, making numbskulls such as me feel a glow of superiority. No one, with all due respect, has ever been intellectually challenged by Roger Moore. Not even me. Now, though, I can't even understand the title of the next 007 film. What does Quantum of Solace really mean? Is solace something that can be quantified? Or did Ian Fleming just throw words together, like an irresponsible God drunk with power on the eve of creation, hoping they would add up to something?
And if I can't understand Bond film titles, then what chance have I got of understanding what is going to happen in a 27km (17-mile) circular tunnel beneath the Geneva countryside this morning at the start of an experiment that, it has been suggested, will unlock the secrets of the universe? Despite the obvious answer to this question (ie: "None"), I am going on a crash course to try to find out what it all means, armed only with a misplaced assurance that I am not the thickest thing in the universe.
What, I want to know, do half the world's particle physicists hope to achieve by triggering a machine called a Large Hadron Collider (LHC) to drive two beams of particles in opposite directions around this 27km ring at 99.9999991% of the speed of light, steering the beams at four points during their circuit into head-on collisions with enough energy to recreate in miniature the cosmic circumstances that existed one trillionth of a second after the big bang?
Everything conspires against understanding. The European Organisation for Nuclear Research is confusingly known by its French acronym Cern, for instance. But that's nothing. Cern's scientists also hope to find extra dimensions, perhaps as many as 10, coiled up in microscopic loops. (I look back on that last sentence wondering what the hell it means.) They hope to create called a Higgs boson, which is a particle that hasn't existed since a split-second after the big bang and yet which, physicists hypothesise, was fundamental, billions of years ago, for the establishing the nature of reality. A Nobel prize-winner called the Higgs boson "the God particle", but every expert I speak to says that this term has no theological import, but is a silly, misleading piece of nomenclature. So thank you, Nobel laureate Leon M Lederman, for muddying further already murky waters.
Discombobulatingly, I read that only 5% of the universe is made of matter that scientists understand. A further 25% is so-called "dark matter", which clusters around galaxies, and the remaining 70% is even more enigmatic "dark energy", which drives the expansion of the universe. Or so scientists claim. But hold on: if scientists only understand 5%, how can they posit anything about the remaining 95%? Aren't they, then, only slightly less ignorant than me? Won't you let me hold on to that dream? Please?
Worse yet, the basic building blocks of the universe seemed to have been named by astrophysics postgrads on crack, or at least a dare. I'm familiar with quark, strangeness and charm, though only because this was the title of a Hawkwind album. I'd never come across a gluon before, though. Although it has an unwonted DIY vibe, like something you might use to hold your bookcase together if you'd lost the Allen key, a gluon turns out to be an elementary particle that causes quarks to interact, and is indirectly responsible for the binding of protons and neutrons together in atomic nuclei. What's more, your everyday gluon has something called negative intrinsic parity and zero isospin. It is, you will be astounded to learn, its own antiparticle. Again, I write these last three sentences and look back at them in bafflement. Oh God, this is hopeless! The only graspable part of particle physics for me is to be found in John Updike's poem Cosmic Gall: "Neutrinos, they are very small/ And do not interact at all." I understand that bit. The poor little sweethearts!
I ring the astronomer royal, Professor Martin Rees, for help. "I believe that the key ideas can be explained by people who need to make a bit of effort to communicate at the right pitch and to people who, similarly, need to think harder than usual," he says. " There is a special scientific vocabulary which is unfamiliar and the mathematics is very complicated, but learning about the experiment is like learning musical notation or like learning Spanish."
Heartened by these words (even though I barely read music or speak Spanish), I settle down for a pub chat with people who have never aspired to unlock the mysteries of the universe. After exhaustively analysing today's other important global event (how will England avoid humiliation in Zagreb this evening?), we reflect on sub-atomic activity. At the Old Queen's Head on the Essex Road in Islington, north London, the conversation starts shallow before plunging deeper. Barry asks me the following: "Did you see Frankie Boyle on Mock the Week?" Perhaps I did. "He said: 'I'm sure they're going to find out some interesting things about protons, but I would add: I don't give a ***.' That's how I feel about it." Barry goes off to buy drinks.
I turn from Barry, whose disregard for intellectual improvement and scientific knowledge is typical of modern Grazia-reading, X-Factor-venerating British society, to his friend Martin, who tries to explain what happened in that trillionth of a second after the big bang by using an empty beer glass - something I secretly hoped someone would do during my research for this article. "Imagine," says Martin, who has an A-level in physics and claims to have read such books as Schrödinger's Cat and the Fabric of the Cosmos and alleges that he's finished A Brief History of Time (as if), "that this glass is a very hot bowl with a frog on its rim." Right. "At the bottom of the glass are some worms that the frog wants to eat." Check. "The frog can't keep still on the glass because it's so hot and so hops around. But as the glass cools, the frog slides down, just like matter did when the universe cooled in that first second." I see, I say (lying). "But imagine if the bottom of the glass had a raised central podium on which the worms sat." Gotcha. "Well, the difference in altitude between the frog at the bottom of the glass and the worms is parallel to the Higgs field of bosons that pertained in that first second and gave all mass-bearing matter its properties." Why does the frog slide down the glass? "Because of time's arrow," says Martin, settling back in his seat proudly. Right. And what do the worms represent? "That's not important." Frankly, I don't think Martin did read all those books. Or if he did, he didn't understand them.
Barry, thankfully, comes back with his round. "And the other thing is," Barry says, "if we are going to get sucked through a black hole on Wednesday morning, I don't find it reassuring when scientists say these are going to be really small, miscroscopic black holes that they're going to be creating in Switzerland. That surely just means it's going to be more painful than if they were big holes, doesn't it?" Marginally, perhaps, I concede. "After all, it's more painful to get sucked through a hole smaller than the eye of a needle than one that's bigger, isn't it?"
I guess. At this point, I rise from the table and bid Barry and Martin, whom I would like to thank for their hospitality and for helping me not at all in increasing my knowledge of particle physics, a fond farewell.
The following day I ring Edward Pattison, a physics teacher at Hayes School in Bromley, south-east London, for a Cern primer, ideally not featuring hot frogs in beer glasses. "You're familiar, I hope with E=mc2," asks Pattison. Absolutely - and not just because it was a song by Big Audio Dynamite. "Well, the more energy, the more mass you create and so you can make big particles - things that previously only existed in the big bang. Tomorrow is just the start, but as the Large Hadron Collider speeds up and up, it'll show what was there in the earliest seconds after the big bang, and then earlier in the big bang and earlier still as it speeds up. We should be able to see dark matter, which is what holds much of the galaxies together. You'll be showing what black holes are like, creating microscopic ones."
Should I be worried that the creation of little black holes at Cern will mean I and my loved ones will be dragged towards Switzerland and thence to oblivion? "No. The smaller they are - and the ones they may create will be tiny - the faster they disappear because they radiate very quickly and so, as it were, evaporate. And anyway, we already find them in space. We shouldn't worry about being gobbled up." Excellent.
Next I ring Professor Jim al-Khalili, who is not only a theoretical nuclear physicist at the University of Surrey, but also has an OBE. Why is this experiment being undertaken now? "We seem to have got to the point in describing the Standard Model where the theory has guesswork in it and it needs to be verified or falsified by experiment." The Standard Model, you'll be eager to learn, describes three of the four known fundamental interactions among the elementary particles that make up all matter. That theory, I learn, predicts the Higgs boson particle which has never been observed except, possibly, by God - and then only billions of years ago for a split second. He might have blinked and missed it. So he might like a mini-reprise. If he exists.
"You see, particle experimentalists have been almost twiddling their thumbs because, up until now, we haven't been able to create the energies necessary to create theses particles - if they indeed exist - while theorists have been theorising wildly," says al-Khalili. "What we can do now is, for a fraction of a second, create the particles, the Higgs bosons, that theorists argue have not been around since the big bang." Why is that important? "Because the Higgs boson, it is hypothesised, endows other particles with its properties. Mass for instance."
Earlier, I had asked Rees to explain to me what a Higgs boson is. "No," he replied firmly. Why not? "It would take too long."
Al-Khalili is more forthcoming. There is a story, he relates, that William Waldegrave, when science minister in Margaret Thatcher's government in the 1980s, launched a competition to explain what the hell this chuffing boson was (he didn't quite use those words). The winner compared the Higgs boson to treacle or molasses through which other particles passed shortly after the big bang. "Another, better, story that appealed to Waldegrave was that of a cocktail party in a room into which a famous celebrity walks, Margaret Thatcher for instance. A huddle forms around her as she walks through the room and she finds it difficult to move. Then other non-celebrities come through the room and find it easy to move around - these are the particles that don't have much mass." Like neutrinos? "That's right." The poor little sweethearts! Hold on, though; what do the guests at the party represent? "The huddle of guests represents the Higgs bosons that form a field. It's, so far, a mathematical description, and the hope is that we will find, by means of the LHC, that it does exist by crashing these protons into each other." In the sub-atomic post-collision debris? "That's it."
What will happen if the experiment doesn't produce Higgs bosons? "Well, the whole hypothesis might be wrong, and we will discover whether it's right or wrong in the next two years. For me, if it is proved wrong then it could be very exciting. All kinds of other possibilities could be discovered."
Indeed, what al-Khalili calls one of the most powerful rival ideas is the so-called supersymmetric particles. What are they? "They are the mystery, the dark matter that has been missing that we have never been able to see." Spooky. How do we know that they exist? "We know dark matter is there because we know how it affects what we do see. It would be nice to see it, which is a possibility that the LHC holds out."
Rees also hopes that the LHC will discover these hypothesised particles. "Speaking as a cosmologist, I'm hopeful - indeed, I rather expect - that the LHC will reveal so-called supersymmetric particles," he says, "because it is quite possible that they are 80% to 90% of what holds the galaxies together." That makes the research sound very important indeed. "It is. It is absolutely the biggest science experiment ever conducted and so very exciting and important." Why? "It may give us an answer to one of the key mysteries about the universe - the "dark matter." Atoms make up only around 10% of the gravitating stuff that holds galaxies together. [I thought it was 5%, but let's not get sidetracked.] The rest probably consists of particles left over from the fiery beginning of the universe, but as yet we have only the haziest idea what they are." Again, I find it cosmically reassuring that even astronomers royal have only hazy ideas about such things.
Is Cern's work worthwhile? After all, Sir David King, the government's former chief science adviser, recently argued that the £500m Britain has contributed to the LHC project diverts top scientists away from tackling the more pressing issues of the age, such as climate change and how to decarbonise the economy. "I hear that kind of objection a lot," says al-Khalili. "It's certainly not going to lead to a quality-of-life improvement, but even from just a cultural point of view it's important to know. There are certain things that a civilised, enlightened society should try to know. If it also captures the admiration and imagination of children who get into science as a result - which I think it will - then it is surely a good thing."
Good point. If future generations are less ignorant than me about the nature of reality and what happened at the dawn of time, then that would be to the glory of humanity (among other things). "It's a good moment to be a physics teacher," says Pattison. "I keep getting stopped in the corridor by kids asking what it's about - the big bang, the LHC, all that. It's the most weird and wonderful things that interest them - stuff like this and quantum physics.
"There's a problem with the curriculum," he adds. "What children study is supposed to be relevant to children's lives. As a result, we no longer teach relativity as part of an A-level course. But it is just this sort of thing that entrances children. If I had my way, I would teach 11-year-olds about space, quantum mechanics and relativity - obviously at a basic level. But to get children thrilled by physics at an early age seems to me to be important and Cern is helping with that."
This resonates for me. I recall that my physics O-level course ended before we had even broached radioactivity. It ended without a big bang, but with something of a whimper. Perhaps that is why I stopped studying physics at 16 and now find myself struggling to understand the exciting things that physicists are doing. Many of the great heroes of physics - Faraday, Rutherford, Einstein, Dirac - never got namechecked in my class (I had to piece them together in remedial reading as an adult); still less were we as thrilled by the subject as the pupils Edward Pattison says have been bombarding him with questions, inspired by what will soon happen beneath some Swiss fields. It would be good if British children are less scientifically ignorant than I am. Perhaps, in my dotage, they could even explain to me what Quantum of Solace means. Or maybe that's too much to hope.
Stuart Jeffries The Guardian, Wednesday September 10 2008