0:00:10 > 0:00:1513.7 billion years after it all began,
0:00:15 > 0:00:20we're about to go back to the beginning of time.
0:00:24 > 0:00:31'With the largest and most complex scientific experiment ever attempted.
0:00:31 > 0:00:35'The Large Hadron Collider, or LHC,
0:00:35 > 0:00:39'has just one simple but audacious aim -
0:00:39 > 0:00:42'to recreate the conditions of the Big Bang...
0:00:44 > 0:00:50'..in an attempt to answer the most profound questions about our universe.'
0:00:53 > 0:00:59The goal of particle physics is to understand the universe in which we live.
0:00:59 > 0:01:06We want to know why things are the way they are, how they work, what everything is...
0:01:06 > 0:01:08we want to understand.
0:01:10 > 0:01:15If you're going to go for the big questions then you have to go for it.
0:01:15 > 0:01:23There is no point in sort of messing around if you really want to understand how the universe ticks.
0:01:23 > 0:01:25The LHC is what you need.
0:01:27 > 0:01:32When the switch is thrown, this could be either the beginning of the end,
0:01:32 > 0:01:36when we find that our theories of what existed just after the Big Bang are right,
0:01:38 > 0:01:45or it could be the end of the beginning where we discover that the universe is more mysterious
0:01:45 > 0:01:50and more beautiful than we could possibly have imagined.
0:02:13 > 0:02:19The Large Hadron Collider spans the French/Swiss border just outside Geneva.
0:02:19 > 0:02:22It's the largest particle accelerator ever constructed.
0:02:26 > 0:02:30I'm Brian Cox and I've been helping build it,
0:02:30 > 0:02:38along with thousands of other scientists at CERN, the European Organisation for Nuclear Research.
0:02:41 > 0:02:44This is the experiment, if you like, Q1, Q2, Q3.
0:02:47 > 0:02:50One of the scientists overseeing the launch
0:02:50 > 0:02:56of the biggest experiment since NASA sent men to the moon is Paul Collier.
0:02:56 > 0:03:00It's going to be a like a moon shot where you see CAPCOM - "Go, go!"
0:03:00 > 0:03:06- There's going to be a bank of experts saying, "Mind it's all right."- Probably yes.
0:03:06 > 0:03:10You must get asked this all the time. Is there a button? Who's going to press it?
0:03:10 > 0:03:14There is not at the moment a button, but I'm considering buying one,
0:03:14 > 0:03:17but the LHC is not like... it's not like a rocket.
0:03:17 > 0:03:21There will not be a countdown, there will not be a button to press.
0:03:21 > 0:03:26Unfortunately, the buttons we have are all computer sequences
0:03:26 > 0:03:29which we have to go through to prepare the machine.
0:03:29 > 0:03:32In a few days, it'll be standing room only
0:03:32 > 0:03:36as the world's most eminent particle physicists
0:03:36 > 0:03:41gather to watch this remarkable machine spring to life.
0:03:41 > 0:03:47What's the scene going to be like on the day that the first beam goes around LHC?
0:03:47 > 0:03:50What's it going to feel like in this control room?
0:03:50 > 0:03:52Yeah, it's going to be an interesting time and quite exciting.
0:03:52 > 0:03:57The first thing I should say is there will be two people on duty here,
0:03:57 > 0:04:00one physicist and one technical engineer,
0:04:00 > 0:04:06so, if you like, two people will be doing the work, and then probably 200 people will be watching them work.
0:04:06 > 0:04:10And of course we will have to... we will have to keep control of that.
0:04:10 > 0:04:12It's brilliant, actually, it's fascinating.
0:04:12 > 0:04:19All of us who work at CERN hope that this will become the world's most renowned Big Bang laboratory.
0:04:22 > 0:04:29That here we'll discover something so fundamental that it will change our understanding of the cosmos.
0:04:32 > 0:04:36Because right now even the brightest minds and the best theories
0:04:36 > 0:04:43all fall short of explaining what occurred as the universe burst into existence.
0:04:44 > 0:04:50Physics is stuck and the only thing left to do is recreate the universe
0:04:50 > 0:04:56as it was a fraction of a second after the Big Bang, and that's what the LHC's designed to do,
0:04:56 > 0:05:01to smash bits of matter together at energies never before achieved
0:05:01 > 0:05:05so we can stare at the face of creation.
0:05:11 > 0:05:16Every civilisation has its own creation story.
0:05:20 > 0:05:24The ancient Chinese, Indian mystics and Christian theologians
0:05:24 > 0:05:29all place a divine creator at the heart of their creation stories.
0:05:30 > 0:05:36Science too has an elaborate story that describes the universe's genesis.
0:05:38 > 0:05:44It tells us how the fundamental constituents of the cosmos took on their form.
0:05:46 > 0:05:51The difference with this story is that we can test it.
0:05:51 > 0:05:57We can find out if it's true by tearing matter apart and looking at the pieces.
0:05:58 > 0:06:05All you need is a machine powerful enough to restage the first moments after creation.
0:06:11 > 0:06:15In the beginning there was nothing.
0:06:15 > 0:06:21No space, no time, just endless nothing.
0:06:24 > 0:06:29Then, 13.7 billion years ago, from nothing...
0:06:35 > 0:06:37..came everything.
0:06:40 > 0:06:43The universe exploded into existence.
0:06:47 > 0:06:53From that fireball of energy emerged the simplest building blocks of matter.
0:07:02 > 0:07:09Finding experimental evidence of these fundamental entities has become the holy grail of physics.
0:07:11 > 0:07:16Well, the universe is an object that is not stable.
0:07:16 > 0:07:19It is expanding and cooling, it's doing things.
0:07:19 > 0:07:24It was therefore different in the past and will be in the future.
0:07:24 > 0:07:27It has a history, it has a life, it has an evolution.
0:07:29 > 0:07:34As the early universe grew, its mysterious primeval constituents
0:07:34 > 0:07:42transformed themselves into atoms, then molecules and eventually stars and planets.
0:07:42 > 0:07:46Now, billions of years on from the Big Bang, the universe is so complex
0:07:46 > 0:07:50that all traces of the enigmatic building blocks are lost.
0:07:53 > 0:07:59Understanding the evolution of the universe requires understanding what it is made of.
0:08:00 > 0:08:05As it turns out, most of that of which the universe is made
0:08:05 > 0:08:08are things that we do not understand at all.
0:08:08 > 0:08:14But we hope that the LHC is about to bridge this profound gap in our knowledge
0:08:14 > 0:08:18by peering further back in time than ever before.
0:08:22 > 0:08:26The LHC is truly colossal.
0:08:26 > 0:08:30Its accelerator ring is 27 kilometres long,
0:08:30 > 0:08:34big enough to encircle a small city.
0:08:34 > 0:08:38And around it we've built four enormous experiments
0:08:38 > 0:08:43that will investigate the Big Bang in exquisite new detail.
0:08:45 > 0:08:50This is my experiment, the experiment that I work on, Atlas,
0:08:50 > 0:08:54and what you can see is just the surface buildings.
0:08:54 > 0:08:58The experiment is actually 100 metres below the ground which is where the LHC is,
0:08:58 > 0:09:05and basically this is just a building that covers cranes where we winch everything down.
0:09:06 > 0:09:09And it's pretty much the last time
0:09:09 > 0:09:17that not only TV crews, but me and the people who built it will be able to go down
0:09:17 > 0:09:24because once it starts operating, the whole area becomes a radiation area, it becomes mildly radioactive.
0:09:26 > 0:09:29You've always got to be worried when you see those things.
0:09:34 > 0:09:38One of the most expensive bits of Atlas, if not the most, was digging the cavern.
0:09:43 > 0:09:48We even have iris scanners, so a little bit of science fiction.
0:09:51 > 0:09:57It's down here in caverns brimming with the latest technology that the Big Bangs will be made.
0:10:02 > 0:10:09We just take little bits of matter, little bits of this stuff and accelerate them to as close
0:10:09 > 0:10:16to the speed of light as we can get and then smash them together right in the middle of that detector
0:10:16 > 0:10:21to recreate the conditions that were present back at the beginning of time.
0:10:26 > 0:10:31The bits of matter we're going to fire around the LHC are called protons.
0:10:31 > 0:10:38They come from a family of particles that give the collider its name, the Hadrons.
0:10:38 > 0:10:43Protons are going to fly around here so close to the speed of light
0:10:43 > 0:10:47that they go round this 27km tunnel 11,000 times a second.
0:10:49 > 0:10:55The ring has two barrels that will shoot beams of protons around in opposite directions.
0:10:58 > 0:11:04When they collide, they'll have the energy equivalent to an aircraft carrier steaming at 30 knots.
0:11:07 > 0:11:13All this energy will be focused into a space just a fraction of the width of a human hair.
0:11:18 > 0:11:24The resulting explosion will be so intense that no-one's quite sure what will happen.
0:11:27 > 0:11:30This machine really is a leap into the unknown.
0:11:30 > 0:11:35I mean it's often said with scientific experiments but I think in this case it's absolutely right.
0:11:35 > 0:11:43We're, we're a step, something like a factor of ten in energy so it's a huge jump up in energy.
0:11:43 > 0:11:47It's a huge jump up in the number of times we can smash particles together per second.
0:11:47 > 0:11:54It collides protons together so often that your chances of seeing something incredibly interesting
0:11:54 > 0:11:59and profound are increased way beyond anything that we've had before
0:11:59 > 0:12:03and I can think of no better place to be actually at the moment.
0:12:03 > 0:12:05This is exciting.
0:12:17 > 0:12:21The dream of understanding the building blocks from which the universe is constructed
0:12:21 > 0:12:25has inspired the greatest minds for over two millennia.
0:12:28 > 0:12:34People have wanted to understand the universe and the stuff around them
0:12:34 > 0:12:36ever since they began to think about it.
0:12:39 > 0:12:43People have always been making theories about what matter is made of.
0:12:44 > 0:12:48But the universe like everybody else is made of little pieces which
0:12:48 > 0:12:51need to be understood in order to understand how the universe works.
0:12:53 > 0:12:57The earliest reference to this concept of the world being made up
0:12:57 > 0:13:03of tiny indivisible pieces dates back to ancient India in the sixth century BC.
0:13:05 > 0:13:13Two centuries on, the ancient Greeks were the first to call these pieces, atoms, which means uncuttable.
0:13:13 > 0:13:21But incredibly it was only in the early 20th century that the concept of the solid atom was shattered...
0:13:23 > 0:13:26..and the modern version of atomic theory was born.
0:13:28 > 0:13:34This new theory described the atom as being made up of a number of even smaller pieces.
0:13:35 > 0:13:39Around the particles which form the nucleus of the atom,
0:13:39 > 0:13:46other electrically charged particles called electrons constantly revolve like planets around the sun.
0:13:47 > 0:13:51This new sub-atomic theory inspired the great experimental physicist
0:13:51 > 0:13:56Ernest Rutherford to invent the art of particle colliding.
0:14:01 > 0:14:04And ever since, we've peeled away the atomic layers.
0:14:06 > 0:14:12Far from being uncuttable, the atom appeared to be more and more like a Russian doll.
0:14:24 > 0:14:29Today particle physicists are busy dreaming up ever more elaborate ways
0:14:29 > 0:14:32to torture matter.
0:14:32 > 0:14:38It almost seems like a paradox that the smaller the thing you are looking for,
0:14:38 > 0:14:40the bigger the instrument you need.
0:14:44 > 0:14:48This is Fermilab and I used to work here for three years.
0:14:48 > 0:14:52It's a beautiful piece of midwestern prairie.
0:14:54 > 0:14:56The reason I worked here is because over there
0:14:56 > 0:15:00is the biggest particle accelerator that's operating in the world today.
0:15:02 > 0:15:06'I served my apprenticeship on a machine here called the Tevatron.'
0:15:08 > 0:15:12Under that lake there, there's a tube that carries a beam of protons one way
0:15:12 > 0:15:18and anti-matter protons the other way and we accelerate them round 50,000 times a second.
0:15:18 > 0:15:19Imagine that!
0:15:19 > 0:15:25It's as close to the speed of light as we can get and then we smash them together, two places actually,
0:15:25 > 0:15:30that red building there, which is called CDF and that blue building over there which is called D zero.
0:15:30 > 0:15:33And their job is to just simply take a picture of those collisions.
0:15:38 > 0:15:41Fermilab has been colliding particles for over 40 years.
0:15:44 > 0:15:47Probing the atom's secrets.
0:15:53 > 0:15:59Leading the way into this sub-atomic frontier was the renowned particle hunter, Leon Lederman.
0:16:06 > 0:16:08We didn't know anything about these particles.
0:16:08 > 0:16:12We knew about atoms, but we had no idea of the complexity of matter.
0:16:16 > 0:16:20What puzzled Lederman was that the more they looked inside the atom,
0:16:20 > 0:16:23the more fundamental particles they found.
0:16:25 > 0:16:29The moment of discovery is really a series of moments.
0:16:29 > 0:16:31The experiment has worked.
0:16:31 > 0:16:35We think it's OK, and then finally, "Hey, look at that, there's an event!"
0:16:39 > 0:16:46Eventually get enough data to say we're beginning to see a class of particles...
0:16:46 > 0:16:50that must have a very important role in the evolution of the universe.
0:16:52 > 0:17:00Because of the work of Lederman and other pioneers, scores of particles completely new to science emerged.
0:17:04 > 0:17:07The up quark, the down quark,
0:17:07 > 0:17:09the electron, the electron neutrino,
0:17:09 > 0:17:13the W-plus and the W-minus.
0:17:13 > 0:17:19As scientists made their discoveries they began to name these fundamental particles.
0:17:19 > 0:17:24The charm quark, the strange quark, the muon, the mu neutrino.
0:17:25 > 0:17:31With these building blocks they came to a remarkable understanding of the world.
0:17:31 > 0:17:33The top quark, the bottom quark,
0:17:33 > 0:17:36the tao and the tao neutrino,
0:17:36 > 0:17:38the Z particle and the photon.
0:17:40 > 0:17:45Now they could explain what anything and everything is made of.
0:17:46 > 0:17:53That's the Standard Model... Oh, no! The gluon, mustn't forget the gluon.
0:17:59 > 0:18:05The Standard Model has gone on to become the basis for all modern particle physics.
0:18:05 > 0:18:10So this was a model that was developed in the 1960s.
0:18:10 > 0:18:14The first experimental breakthroughs
0:18:14 > 0:18:20showing that it might be true came in the 1970s and I would say,
0:18:20 > 0:18:25was really established by experiments at CERN in the 1980s and the 1990s.
0:18:26 > 0:18:32Experimental science has shown that the nature of matter is more complex than anyone had foreseen.
0:18:35 > 0:18:42Rather than a single atom, it turns out that nature uses 16 different fundamental particles
0:18:42 > 0:18:45to make everything we see in the cosmos.
0:18:47 > 0:18:53The Standard Model itself is a triumph. We have not only
0:18:53 > 0:19:00the particles but the mathematics that gives a huge coherence
0:19:00 > 0:19:04to our world on the microscopic level.
0:19:14 > 0:19:19The Standard Model accurately describes the essential constituents of the universe.
0:19:21 > 0:19:27It's no exaggeration to say it's one of the most successful theories in the history of science.
0:19:33 > 0:19:37And yet many physicists feel uneasy about the Standard Model.
0:19:41 > 0:19:45The maths is too complex, even ugly.
0:19:49 > 0:19:54When scientists talk about beauty in a physical theory, they mean that
0:19:54 > 0:20:04it can describe a whole range of diverse phenomena with hopefully simple concepts and simple maths.
0:20:04 > 0:20:07Take Einstein's theory of general relativity,
0:20:07 > 0:20:11our theory of gravitation, you can write it down in one line.
0:20:19 > 0:20:21Now the trouble with the Standard Model is,
0:20:21 > 0:20:30well, it takes pages to write down but also there are elements in it that are mysterious, arbitrary even.
0:20:44 > 0:20:49There's something spooky about this Standard Model.
0:20:49 > 0:20:53It doesn't really work, so we know that there is something sick in our theory.
0:20:55 > 0:21:02For example, we have at the moment what we call a Standard Model of particle physics, works great.
0:21:02 > 0:21:07Only one small problem, if you write down the equations of this model
0:21:07 > 0:21:11it would seem to suggest that no particles would have any mass.
0:21:11 > 0:21:12Clearly that's not true.
0:21:18 > 0:21:22For all its power, the Standard Model overlooked
0:21:22 > 0:21:26one of the most basic fundamental properties of our world.
0:21:27 > 0:21:30It was incomplete in its description of the universe.
0:21:38 > 0:21:46What's missing is an explanation, a mechanism for how the fundamental particles acquire mass.
0:21:46 > 0:21:52Now we know intuitively that the things in the world around us have mass.
0:21:53 > 0:21:54We can feel it.
0:21:54 > 0:21:59It's... Well, it's what makes stuff, stuff.
0:21:59 > 0:22:04But what is mass and why does it exist?
0:22:04 > 0:22:11Sounds simple but it's become one of the most difficult and challenging problems in physics.
0:22:18 > 0:22:22There must have been a time in the early universe
0:22:22 > 0:22:26when the particles became substantial and took on their mass.
0:22:31 > 0:22:36The best theory we have to explain how this happened was dreamt up one day
0:22:36 > 0:22:41by a British physicist Peter Higgs, whilst walking in the Scottish Highlands.
0:22:44 > 0:22:49He came up with a theoretical mechanism that could explain
0:22:49 > 0:22:53how some but not all particles attain mass.
0:22:55 > 0:23:00The Higgs mechanism works by filling the universe with a field, the Higgs field,
0:23:00 > 0:23:05and by the universe I don't just mean up there amongst the stars.
0:23:05 > 0:23:09I mean here in front of me, and inside of me, and particles
0:23:09 > 0:23:15acquire mass by interacting with the Higgs Field, by talking to it.
0:23:18 > 0:23:24The theory is that every particle in the universe is traversing this invisible Higgs Field
0:23:24 > 0:23:30and some particles like the quarks and electrons acquire mass as they pass through.
0:23:33 > 0:23:37Whereas mass-less particles, particles like photons,
0:23:37 > 0:23:43don't interact with the Higgs Field and they just pass through the universe at the speed of light.
0:23:53 > 0:23:59The Higgs brings simplicity and beauty to a nature which looks too complicated.
0:24:01 > 0:24:08It introduces a kind of symmetry and a kind of beauty to nature which gives us an understanding of
0:24:08 > 0:24:13one of the most puzzling features of this little model I told you about, the Standard Model.
0:24:14 > 0:24:19The Higgs Field may solve the problem of missing mass in the Standard Model
0:24:19 > 0:24:23but the only trouble is we haven't been able to detect it yet.
0:24:25 > 0:24:29But there is hope, because it's a law of quantum physics
0:24:29 > 0:24:33that all fields must have an associated particle.
0:24:35 > 0:24:42And it's a key prediction of this Higgs theory that there should be a quantum of this field, a particle
0:24:42 > 0:24:45associated with it and that's what's called the Higgs boson.
0:24:45 > 0:24:50Is there a Higgs particle, and if there is, how does it appear?
0:24:50 > 0:24:53How does it come about to simplify our view of the world?
0:24:53 > 0:24:56It would be a tremendous discovery.
0:24:57 > 0:25:02If we can find this new fundamental particle, the Higgs boson,
0:25:02 > 0:25:07then we'll be one step closer to understanding how the universe came to be the way it is.
0:25:07 > 0:25:12No wonder Lederman called it the God particle.
0:25:12 > 0:25:18The Higgs mechanism is our best attempt to repair the Standard Model
0:25:18 > 0:25:22but over 40 years after it was first thought of,
0:25:22 > 0:25:28the Higgs particle, the one thing that could prove the theory correct hasn't been found.
0:25:30 > 0:25:33EXPLOSION
0:25:33 > 0:25:39So the only way to prove the theory correct is to try and create the Higgs boson
0:25:39 > 0:25:42for an instant inside a particle collider.
0:25:49 > 0:25:53Some thought that Fermilab with its powerful Tevatron collider would have found it.
0:25:56 > 0:26:00Fermilab is working day and night, night and day with a machine
0:26:00 > 0:26:04that's ever increasing the number of collisions
0:26:04 > 0:26:10but I would say probabilistically we won't find it.
0:26:12 > 0:26:18Ever since the Higgs particle was dreamt up and despite billions of dollars worth of research,
0:26:18 > 0:26:25Fermilab has not seen even a hint that the God particle exists.
0:26:32 > 0:26:35So the hunt for the Higgs boson is about to step up a gear at CERN...
0:26:37 > 0:26:42..where Europe is about to overtake America in the high-energy particle-hunting race.
0:26:48 > 0:26:52Building an instrument capable of recreating the early universe
0:26:52 > 0:26:55and finding the massive Higgs boson has taken decades.
0:26:58 > 0:27:03We've had to devise new ways of handling uniquely, not one,
0:27:03 > 0:27:07but the two most powerful proton beams ever created.
0:27:10 > 0:27:15There'll be a beam of protons going that way in that pipe at almost the speed of light,
0:27:15 > 0:27:19another beam of protons going that way in that pipe,
0:27:19 > 0:27:25at almost the speed of light and they'll cross inside Atlas and recreate the conditions
0:27:25 > 0:27:29that were present just after the beginning of the universe.
0:27:29 > 0:27:32Fantastic.
0:27:32 > 0:27:37A ring of 9,500 super-conducting magnets has been designed
0:27:37 > 0:27:42to safely contain and control the direction of the proton beams.
0:27:42 > 0:27:4713,000 amps of current to the magnets,
0:27:47 > 0:27:551.9 Kelvin minus 271 degrees, colder than the space between the galaxies to cool the magnets down
0:27:55 > 0:28:00and then the two beam pipes, one there and one there.
0:28:01 > 0:28:07All joined up, these magnets make a collider four times longer than Fermilab's Tethertron.
0:28:08 > 0:28:13To put the scale of the experiment in context, each circuit the protons make
0:28:13 > 0:28:21is the same distance as the half-way mark from England to France along the Channel Tunnel
0:28:21 > 0:28:24and they'll do this 11,000 times a second.
0:28:33 > 0:28:39To understand how we hope to transform two tiny protons
0:28:39 > 0:28:44into a massive Higgs boson requires the help of a genius.
0:28:46 > 0:28:51Einstein's astonishing insight into the connection between matter
0:28:51 > 0:28:57and energy is the engine which drives all particle physics.
0:28:58 > 0:29:01His theory used just five characters
0:29:01 > 0:29:07but with them he had shown us the way to a modern form of alchemy.
0:29:08 > 0:29:12Einstein's famous equation, E = mc2,
0:29:12 > 0:29:16that basically says that energy and mass are two sides of the same coin.
0:29:16 > 0:29:19They're basically the same thing and they're interchangeable.
0:29:19 > 0:29:23In this idea I think that Einstein was truly the first.
0:29:23 > 0:29:25Mass is just a form of energy.
0:29:25 > 0:29:27That was a very deep insight of Einstein.
0:29:27 > 0:29:33There's absolutely no question. And there was no precedent for that idea.
0:29:33 > 0:29:38One thing we take for granted as particle physicists is that we can convert energy into mass.
0:29:38 > 0:29:42We do it all the time. That's how the LHC essentially works.
0:29:42 > 0:29:46It speeds protons around faster and faster, gives them more and more energy
0:29:46 > 0:29:52and then smashes them together, and the idea is to make new particles, like the Higgs boson, for example,
0:29:52 > 0:29:58that's many, many tens or even hundreds of times heavier than the protons that collided to make it.
0:30:02 > 0:30:08So Einstein's most famous equation is at the heart of the hunt for the Higgs particle.
0:30:08 > 0:30:13In effect, the Large Hadron Collider is a relativity machine.
0:30:14 > 0:30:21When the ultra high-speed protons smash into one another, they'll have phenomenal amounts of energy.
0:30:23 > 0:30:28Each collision can produce hundreds of new particles.
0:30:28 > 0:30:32For a moment, we've created a mini Big Bang.
0:30:32 > 0:30:35It's in these "events", as they're known,
0:30:35 > 0:30:41that we hope for a fleeting moment that the massive Higgs particle will be seen
0:30:41 > 0:30:45for the first time in 13.7 billion years.
0:30:47 > 0:30:52These will be the highest-energy collisions we've ever made.
0:30:52 > 0:30:55It's led some to wonder if we know what we're doing.
0:31:02 > 0:31:06One of the wildest speculations is that the LHC will be capable
0:31:06 > 0:31:10of creating black holes that will devour the Earth.
0:31:13 > 0:31:17I get page after page of e-mails saying,
0:31:17 > 0:31:21"You maniac, you're going to destroy the planet!"
0:31:21 > 0:31:24What do you say to these people? You must get the same e-mails.
0:31:24 > 0:31:27I've seen that too. It's what everybody wants to know about
0:31:27 > 0:31:30cos it's such a cool idea, right? Here we have LHC,
0:31:30 > 0:31:34looking at the universe at the earliest time. What if it could make black holes?
0:31:34 > 0:31:37Wow! Two interesting things happening at the same time.
0:31:37 > 0:31:39But personally speaking I think it's incredibly unlikely.
0:31:39 > 0:31:42I don't think there's any way they can be made.
0:31:42 > 0:31:45Don't forget, people take this very seriously.
0:31:45 > 0:31:48When there was this theory that came out that we could make black holes,
0:31:48 > 0:31:53CERN took it so seriously that they made this special risk assessment, really just to make sure
0:31:53 > 0:31:58that there wasn't going to be anything untoward happening. So no-one need worry.
0:31:58 > 0:32:01I really think that there's absolutely no way we are going
0:32:01 > 0:32:05to make anything like that. It's just too strange a theory.
0:32:06 > 0:32:12Even if black holes do show up, they will not destroy the Earth.
0:32:12 > 0:32:16'Much more likely is that the LHC will create Higgs particles
0:32:16 > 0:32:21'and we've had to go to extraordinary lengths to be sure of detecting them.'
0:32:21 > 0:32:26Not one, but four colossal particle detectors have been installed
0:32:26 > 0:32:31around the ring to take pictures of what happens when protons collide.
0:32:37 > 0:32:41Early particle detectors also took photographs of similar events.
0:32:41 > 0:32:44It's these pictures that first captured
0:32:44 > 0:32:47the fundamental particles in the Standard Model.
0:32:47 > 0:32:51Here is evidence for a neutrino caught on film.
0:32:54 > 0:32:58This was the first glimpse of the W boson at CERN in the 1980s.
0:33:00 > 0:33:04And the Z boson's scientific debut.
0:33:06 > 0:33:08But the one missing picture,
0:33:08 > 0:33:13the one that would go on the wall if we find it, is the Higgs boson.
0:33:16 > 0:33:20The reason it's been so elusive is to do with its mass.
0:33:22 > 0:33:26Our theories predict that the Higgs particle is immensely heavy
0:33:26 > 0:33:29and it's a general rule in particle physics
0:33:29 > 0:33:32that heavy particles are unstable.
0:33:32 > 0:33:36They simply fall apart into lighter particles.
0:33:36 > 0:33:40So if the Higgs is a real part of nature,
0:33:40 > 0:33:44it would have long ago vanished from the early universe.
0:33:44 > 0:33:47And today, even if we manage to recreate the Higgs,
0:33:47 > 0:33:50- it'll disappear... - EXPLOSION
0:33:50 > 0:33:53..before we can see it.
0:33:54 > 0:33:59Instead, we'll be hunting for its decay artefacts,
0:33:59 > 0:34:05other Standard Model particles like W and Z bosons, quarks and muons.
0:34:05 > 0:34:11This is a simulation of a single proton/proton collision at the LHC.
0:34:11 > 0:34:15It's actually the simulation of the production of a Higgs particle.
0:34:15 > 0:34:17Now, the Higgs particle you don't see, of course.
0:34:17 > 0:34:20It just decays in a fraction of a second.
0:34:20 > 0:34:23But what you do see is the smoking gun,
0:34:23 > 0:34:27in this case, two very clear red tracks,
0:34:27 > 0:34:30these two particles here, called muons,
0:34:30 > 0:34:33that have gone straight out to the very edges of the detector.
0:34:35 > 0:34:40And if we see not just one collision like this, but maybe 10, maybe 100,
0:34:40 > 0:34:43then we'll have discovered the Higgs and for the first time
0:34:43 > 0:34:47we'll understand the origin of mass in the universe.
0:34:51 > 0:34:54That is if the experiment works.
0:34:54 > 0:35:01Switching on the planet's largest particle collider is an anxious time for everyone.
0:35:04 > 0:35:08The sheer magnitude of this complex machine
0:35:08 > 0:35:10and the power in the beam
0:35:10 > 0:35:14is something that nobody's ever done in the world,
0:35:14 > 0:35:19and we have to not forget anything important that we destroy something.
0:35:24 > 0:35:28It takes months to cool each section of the LHC down
0:35:28 > 0:35:33to its operating temperature of less than minus 271 degrees Celsius,
0:35:33 > 0:35:38no mean feat since this is colder than deep space.
0:35:40 > 0:35:46And if anything fails, it'll be a major setback in the search for the Higgs.
0:35:49 > 0:35:55It would take us two, three months to repair that part of the machine, even though it's based on a sector basis,
0:35:55 > 0:35:58and it takes enormous time to warm up the whole sector
0:35:58 > 0:36:03of 3.3 kilometres, the cryogenic, so there is a lot of time issues involved.
0:36:03 > 0:36:07Even one week is too long so certainly two, three months is very long.
0:36:07 > 0:36:13People are waiting for beam, waiting for physics. We can't afford that.
0:36:14 > 0:36:17So CERN's management decided last year to cancel
0:36:17 > 0:36:21an engineering run scheduled to test the entire ring.
0:36:22 > 0:36:27Instead of beginning slowly with some safe but dull low-energy collisions,
0:36:27 > 0:36:32the machine's first run will accelerate particles
0:36:32 > 0:36:35to high energies straight away.
0:36:36 > 0:36:40If it works, this incredible machine, this vast effort
0:36:40 > 0:36:44of thousands of scientists and billions of Euros
0:36:44 > 0:36:48is certain to change our understanding of the universe.
0:36:51 > 0:36:55If the Higgs exists, then it'll be created here
0:36:55 > 0:36:59in the centre of Atlas over the next few years.
0:36:59 > 0:37:05If we don't see it, then it wouldn't help to build a bigger machine and a bigger accelerator.
0:37:05 > 0:37:09It really means that the God particle doesn't exist.
0:37:14 > 0:37:18And for some theorists, finding nothing at the LHC
0:37:18 > 0:37:21is actually the most exciting prospect.
0:37:25 > 0:37:29It can be argued that the most interesting discovery at the LHC
0:37:29 > 0:37:33would be that we cannot find the Higgs,
0:37:33 > 0:37:35proving practically that it isn't there.
0:37:35 > 0:37:39That would mean that we really haven't understood something,
0:37:39 > 0:37:43very deeply not understood something. That's a very good scene for science.
0:37:43 > 0:37:46Revolutions sometimes come from the fact that you hit a wall
0:37:46 > 0:37:50and you realise that you truly haven't understood anything.
0:37:59 > 0:38:03The theorists may long for a revolution but most of us
0:38:03 > 0:38:07are pretty sure that the Higgs boson is a real part of nature.
0:38:11 > 0:38:16What are the chances we're ever going to solve the mystery of mass?
0:38:34 > 0:38:37For the first time in a generation
0:38:37 > 0:38:41we stand at a crossroads in physics
0:38:41 > 0:38:45and that's what makes this place so exciting,
0:38:45 > 0:38:50because nobody knows what the next steps are in our quest
0:38:50 > 0:38:53to understand the universe,
0:38:53 > 0:38:57but I'm convinced that this place will show us the way
0:38:57 > 0:38:59to new physics.
0:39:19 > 0:39:22Even if the Higgs boson does turn up at the launch party,
0:39:22 > 0:39:26work at the Big Bang machine won't stop.
0:39:26 > 0:39:31Beyond the mystery of mass lies a much thornier challenge
0:39:31 > 0:39:36for the Standard Model, a puzzle that defeated even Einstein.
0:39:45 > 0:39:49Why does the world appear to obey different rules?
0:39:49 > 0:39:53There's the world of the small, the quantum world,
0:39:53 > 0:39:56that the Standard Model explains so well,
0:39:56 > 0:39:59and then there's the world of the large,
0:39:59 > 0:40:02the world of stars and planets and galaxies.
0:40:02 > 0:40:05The Standard Model has nothing to say about how they interact.
0:40:09 > 0:40:13And it's a problem we've yet to solve.
0:40:25 > 0:40:30When you want to understand the way the universe has evolved -
0:40:30 > 0:40:35so what happened to it straight after it began and how it got to how it is today -
0:40:35 > 0:40:38you've not only got to know about how many galaxies there are,
0:40:38 > 0:40:41the way that stars work and the way that planets form...
0:40:44 > 0:40:48..you've also got to know what the fundamental building blocks
0:40:48 > 0:40:51of all those things are and how they interact together.
0:40:53 > 0:40:57And in particular it's not only the stuff that's in the universe,
0:40:57 > 0:41:00but the way that stuff talks to other stuff. It's about the forces.
0:41:01 > 0:41:07If these forces didn't act on matter, nothing would happen.
0:41:07 > 0:41:09The stars wouldn't shine,
0:41:09 > 0:41:14the atoms that make up the planetary bodies would fall apart.
0:41:16 > 0:41:19The universe would disintegrate.
0:41:22 > 0:41:27It's the forces in the Standard Model which hold everything together.
0:41:29 > 0:41:33There are four forces that we know of in the universe at the moment,
0:41:33 > 0:41:37the thing called the strong force which sticks nuclei together...
0:41:37 > 0:41:40This strong force is what binds the quarks together
0:41:40 > 0:41:44to form the nucleus at the heart of the atom.
0:41:44 > 0:41:49There's electro-magnetism, that kind of quite familiar force to everyone.
0:41:49 > 0:41:54This force holds the electrons in orbit around the atomic nucleus.
0:41:55 > 0:41:59And a thing called the weak force which is quite unfamiliar
0:41:59 > 0:42:02but it allows the sun to shine, so it's incredibly important.
0:42:03 > 0:42:09The weak force explains why some atoms undergo radioactive decay,
0:42:09 > 0:42:13the process which fuels every star in the universe.
0:42:20 > 0:42:24But, crucially, one force is missing from the Standard Model.
0:42:32 > 0:42:34Gravity.
0:42:37 > 0:42:40In the everyday world you and I inhabit,
0:42:40 > 0:42:43clearly gravity is all around us.
0:42:47 > 0:42:50It's what keeps you in your chair at home,
0:42:50 > 0:42:53it's what keeps Earth in orbit around the Sun
0:42:53 > 0:42:56and it's what holds our galaxy together.
0:43:05 > 0:43:09And Einstein too thought gravity was pretty important.
0:43:10 > 0:43:15His General Theory of Relativity beautifully describes
0:43:15 > 0:43:19how every celestial body interacts with every other body
0:43:19 > 0:43:21through this force.
0:43:26 > 0:43:31'The universe on the grand scale can be entirely explained
0:43:31 > 0:43:34'by Einstein's equations.'
0:43:36 > 0:43:38But there's a problem.
0:43:41 > 0:43:46The moment we try to merge General Relativity with the Standard Model,
0:43:46 > 0:43:49we encounter immense difficulties,
0:43:49 > 0:43:54so immense, in fact, that nobody's been able to work out how to do it.
0:43:54 > 0:43:59They're completely incompatible pictures of the universe.
0:43:59 > 0:44:03The problem is they're pictures of the same universe.
0:44:03 > 0:44:05Something has to be wrong.
0:44:06 > 0:44:12The Standard Model is incredibly powerful at describing the world of the small, the quantum world.
0:44:15 > 0:44:21But as soon as you try to add gravity into the Standard Model equations, they break.
0:44:23 > 0:44:28Einstein was searching for just one set of equations
0:44:28 > 0:44:32that would work on both planets and particles,
0:44:32 > 0:44:35nothing less than a theory of everything.
0:44:37 > 0:44:41This was Einstein's greatest failure.
0:44:41 > 0:44:45At the smallest distance scales, his theory just falls apart.
0:44:46 > 0:44:51Einstein spent the last 30 years of his life trying to rectify the problem
0:44:51 > 0:44:53but he never succeeded.
0:45:01 > 0:45:07'53 years after Einstein's death his theory of everything still eludes us.'
0:45:16 > 0:45:19This is CERN's theory corridor.
0:45:21 > 0:45:24Inside each room is a theoretical physicist.
0:45:28 > 0:45:31And inside the head of each theoretical physicist
0:45:31 > 0:45:35is a different conception of our universe.
0:45:38 > 0:45:43'The first physicist to coin the term "a theory of everything"
0:45:43 > 0:45:46'was CERN's John Ellis.'
0:45:48 > 0:45:51When we talk about a theory of everything,
0:45:51 > 0:45:56we mean a theory of the fundamental constituents
0:45:56 > 0:46:00of matter and the forces between them.
0:46:00 > 0:46:07You can somehow think of it as a sort of cosmic genetic code, right?
0:46:07 > 0:46:10In fact, the Standard Model already you can regard
0:46:10 > 0:46:16as being a sort of genetic code for making up the regular visible matter in the universe.
0:46:16 > 0:46:21All the visible matter in the universe is made up out of the same quarks and electrons and things
0:46:21 > 0:46:23that we can measure in the laboratory.
0:46:23 > 0:46:29Somehow or other, these things can be combined in all sorts of ways
0:46:29 > 0:46:34to make people as complicated and bizarre as you or me.
0:46:36 > 0:46:42The search for this cosmic genetic code is the ultimate quest for physicists.
0:46:42 > 0:46:45We want to finish what Einstein started.
0:46:50 > 0:46:54You might wonder why we believe the baffling complexity of the universe
0:46:54 > 0:46:58can ever be reduced to a single theory.
0:46:58 > 0:47:02The answer can be found back at the Big Bang.
0:47:04 > 0:47:09If we journey back through time, the universe shrinks,
0:47:09 > 0:47:14galaxies disappear and the stars evaporate into gas.
0:47:18 > 0:47:26As we draw to within a couple of hundred thousand years of the Big Bang, the universe becomes opaque.
0:47:29 > 0:47:33Eventually we approach the moment when atoms vanish.
0:47:36 > 0:47:39Now things get really strange.
0:47:41 > 0:47:45Seconds away from the Big Bang, the atomic nuclei break apart.
0:47:48 > 0:47:52The universe is now so small and so hot
0:47:52 > 0:47:57that only the naked fundamental particles of the Standard Model exist.
0:48:01 > 0:48:04This is the time of the Higgs.
0:48:06 > 0:48:11It's at this time that the LHC will spend most of its working life.
0:48:14 > 0:48:20This is what this machine was designed to do, to open a window onto the time
0:48:20 > 0:48:23when the Higgs ruled the universe.
0:48:23 > 0:48:28But some of us believe that it may give us a glimpse of something even more profound.
0:48:31 > 0:48:36Beyond the Higgs, the universe continues to condense.
0:48:36 > 0:48:39Eventually even the fundamental particles
0:48:39 > 0:48:42of the Standard Model disappear.
0:48:42 > 0:48:46We are approaching the moment of the Big Bang itself.
0:48:46 > 0:48:49In the instant of creation there must have been a time
0:48:49 > 0:48:54when the universe was nothing more than a single, unimaginably hot,
0:48:54 > 0:48:57fantastically small entity,
0:48:57 > 0:49:01the entire universe was made of just one thing,
0:49:01 > 0:49:04pregnant with possibilities.
0:49:07 > 0:49:10Remarkably, we have a highly speculative theory
0:49:10 > 0:49:13that attempts to describe this era.
0:49:13 > 0:49:16It's called String Theory.
0:49:17 > 0:49:23The String Theory concept is that particles, the objects that exist,
0:49:23 > 0:49:26are actually vibrations of a single string
0:49:26 > 0:49:31and like, like the notes of a piano,
0:49:31 > 0:49:36they vibrate once or twice or three times, and each note corresponds to a different particle.
0:49:36 > 0:49:40So if everything was just a note that you could play on the piano,
0:49:40 > 0:49:43a single piano, maybe a single string, that would be a very simple idea.
0:49:43 > 0:49:49String theory is certainly the best candidate we have for a theory of everything which would combine
0:49:49 > 0:49:54all the different forces, all the different particles and make a decent cup of coffee.
0:49:56 > 0:50:00These peculiar strings, if they exist,
0:50:00 > 0:50:06are our best attempt to understand what might underpin everything.
0:50:06 > 0:50:09They're unimaginably small,
0:50:09 > 0:50:12they were the first things in the universe,
0:50:12 > 0:50:19and they have multiplied to create every particle we see today.
0:50:27 > 0:50:30Incredibly, String Theory may succeed
0:50:30 > 0:50:33where the Standard Model fails...
0:50:34 > 0:50:38..because when gravity is added to the Standard Model,
0:50:38 > 0:50:42the equations break down and produce infinities.
0:50:47 > 0:50:51These horrendous infinite answers come about,
0:50:51 > 0:50:56we think, because we're treating the particles as being tiny little points
0:50:56 > 0:50:59and when you bring these tiny little points together
0:50:59 > 0:51:02the gravitational force becomes incredibly strong
0:51:02 > 0:51:05and we don't know how to handle that.
0:51:08 > 0:51:13Gravity can become so strong because point light particles
0:51:13 > 0:51:16can get infinitely close together...
0:51:17 > 0:51:22..and that means that the gravitational force between them
0:51:22 > 0:51:24becomes infinitely strong.
0:51:26 > 0:51:30Supposing the particles, instead of being tiny little points,
0:51:30 > 0:51:35were sort of warm, fuzzy, extended things, right?
0:51:35 > 0:51:40Then you could bring them together and the gravitational force would not blow up in your face.
0:51:40 > 0:51:45So maybe that's the answer, maybe particles are not actually points
0:51:45 > 0:51:50but actually extended objects, maybe they're pieces of string.
0:51:51 > 0:51:57Strange as it may seem, by imagining a universe made of string,
0:51:57 > 0:52:02we have a way of creating the extra space that gravity needs to work.
0:52:07 > 0:52:12The extraordinary thing about String Theory is that, for the first time
0:52:12 > 0:52:16in the history of physics, it offers a bridge
0:52:16 > 0:52:21between the two contradictory descriptions of the world we see today -
0:52:21 > 0:52:26the Standard Model of particle physics and Einstein's General Theory of Relativity.
0:52:26 > 0:52:30It's a contender for a theory of everything.
0:52:30 > 0:52:36What would Einstein have thought of our current attempts to bring General Relativity into the fold?
0:52:36 > 0:52:39What would he have thought of String Theory?
0:52:39 > 0:52:44I think he would have been delighted for a while.
0:52:44 > 0:52:49That is to say, he would have been fascinated by the beauty of the theory
0:52:49 > 0:52:56till he realised that it didn't have any convincing predictions
0:52:56 > 0:53:02that we could check now. He would be very unhappy about that.
0:53:03 > 0:53:06Einstein would have spurned String Theory
0:53:06 > 0:53:12because so far nobody has produced a single prediction that we can put to the test.
0:53:12 > 0:53:17It remains an intriguing but unprovable concept.
0:53:21 > 0:53:25This is science at its most esoteric.
0:53:25 > 0:53:32It's like philosophy, religion even, because all it has going for it is beauty.
0:53:32 > 0:53:39We have a mathematical description of the first few moments after creation but nothing more.
0:53:40 > 0:53:47To see far enough back in time to discover a string would require a collider the size of our galaxy.
0:53:49 > 0:53:55For now, the LHC is as large as it gets,
0:53:55 > 0:54:01although perhaps instead of creating a string we can search for one of its most remarkable properties.
0:54:05 > 0:54:09The original idea was that, OK if they're not points, maybe they extend out
0:54:09 > 0:54:13along some sort of line, might be a curvy line, like a piece of string.
0:54:13 > 0:54:15That's named the String Theory.
0:54:15 > 0:54:18In fact, people realised that that's not enough.
0:54:18 > 0:54:22If they're going to be extended in one dimension,
0:54:22 > 0:54:27they're probably extended in two dimensions, maybe three dimensions, maybe more dimensions.
0:54:27 > 0:54:33So in fact String Theory nowadays is a bit of a wrong name, right?
0:54:33 > 0:54:37And in fact people nowadays often talk about something called M Theory,
0:54:37 > 0:54:43which is supposed to contain this idea that particles are not just extended in one dimension
0:54:43 > 0:54:46but maybe M for many dimensions.
0:54:52 > 0:54:55Multiple dimensions are notoriously difficult to imagine,
0:54:55 > 0:54:58let alone detect,
0:54:58 > 0:55:02yet one of the wildest hopes is that we might just catch sight
0:55:02 > 0:55:05of an extra dimension at the LHC.
0:55:07 > 0:55:09Space has three dimensions,
0:55:09 > 0:55:13we all know that. But we think that maybe each point of our space
0:55:13 > 0:55:17is actually not a point but a sort of little sphere
0:55:17 > 0:55:20with extra dimensions inside.
0:55:20 > 0:55:24And if we could penetrate into these little spheres at the energies
0:55:24 > 0:55:28that we are exploring, maybe we'll find these extra dimensions.
0:55:28 > 0:55:34That idea of extra dimensions is very connected with String Theory.
0:55:40 > 0:55:44If we do detect another dimension at the LHC,
0:55:44 > 0:55:52then we'll be able to show that the universe is at least a place where strings might feel at home,
0:55:52 > 0:55:59a universe in which gravity and the other forces can harmoniously co-exist in our mathematics.
0:56:00 > 0:56:06We'll be one step closer to completing our story of creation.
0:56:08 > 0:56:11This is maybe the most important thing about the LHC.
0:56:11 > 0:56:15For a long time now, we've been speculating about String Theory,
0:56:15 > 0:56:17about extra dimensions,
0:56:17 > 0:56:21but we haven't had hard facts to confront them with.
0:56:24 > 0:56:30Now, if we find extra dimensions at the LHC, that would be kind of a hint
0:56:30 > 0:56:34that String Theory might be right, but it wouldn't be a proof.
0:56:34 > 0:56:37It would be, if you like, a smoking gun for String Theory.
0:56:37 > 0:56:41But it would encourage us to think that maybe we were on the right track.
0:56:44 > 0:56:47It would be a tremendous breakthrough,
0:56:47 > 0:56:50but with today's technology
0:56:50 > 0:56:53finding another dimension
0:56:53 > 0:56:56is highly unlikely.
0:57:00 > 0:57:06The LHC will allow us to explore the earliest times in the universe.
0:57:06 > 0:57:13Within a few years it will tell us whether the Higgs boson, the God particle, really exists.
0:57:16 > 0:57:21And it may even tell us that there are extra dimensions in the universe.
0:57:21 > 0:57:23This is exploration.
0:57:23 > 0:57:27It's a journey to the very edge of our understanding.
0:57:33 > 0:57:36Today is the moment.
0:57:37 > 0:57:41We don't know what the LHC is going to discover.
0:57:41 > 0:57:46We've got all these ideas. They can't all be right, a lot of them are going to be proved to be wrong.
0:57:46 > 0:57:49But if just one of them gets proved to be right,
0:57:49 > 0:57:54then it's going to be the most exciting event in my scientific lifetime.
0:57:56 > 0:58:02And, for me, that's what science at the Large Hadron Collider is all about.
0:58:02 > 0:58:06It represents the noblest side of humanity -
0:58:06 > 0:58:10our need to know.
0:58:32 > 0:58:36Subtitles by Red Bee Media Ltd.
0:58:36 > 0:58:40E-mail subtitling@bbc.co.uk