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  • This is the Large Hadron Collider.

  • It's 27 kilometers in circumference;

  • it's the biggest scientific experiment ever attempted.

  • Over 10,000 physicists and engineers

  • from 85 countries around the world

  • have come together over several decades

  • to build this machine.

  • What we do is we accelerate protons --

  • so, hydrogen nuclei --

  • around 99.999999

  • percent the speed of light.

  • Right? At that speed, they go around

  • that 27 kilometers 11,000 times a second.

  • And we collide them with another beam of protons

  • going in the opposite direction.

  • We collide them inside giant detectors.

  • They're essentially digital cameras.

  • And this is the one that I work on, ATLAS.

  • You get some sense of the size --

  • you can just see these EU standard-size

  • people underneath.

  • (Laughter)

  • You get some sense of the size: 44 meters wide,

  • 22 meters in diameter, 7,000 tons.

  • And we re-create the conditions that were present

  • less than a billionth of a second after the universe began --

  • up to 600 million times a second

  • inside that detector -- immense numbers.

  • And if you see those metal bits there --

  • those are huge magnets that bend

  • electrically-charged particles,

  • so it can measure how fast they're traveling.

  • This is a picture about a year ago.

  • Those magnets are in there.

  • And, again, an EU standard-size real person,

  • so you get some sense of the scale.

  • And it's in there that those mini-Big Bangs will be created,

  • sometime in the summer this year.

  • And actually, this morning, I got an email

  • saying that we've just finished, today,

  • building the last piece of ATLAS.

  • So as of today, it's finished. I'd like to say

  • that I planned that for TED,

  • but I didn't. So it's been completed as of today.

  • (Applause)

  • Yeah, it's a wonderful achievement.

  • So, you might be asking, "Why?

  • Why create the conditions that were present

  • less than a billionth of a second after the universe began?"

  • Well, particle physicists are nothing if not ambitious.

  • And the aim of particle physics is to understand

  • what everything's made of, and how everything sticks together.

  • And by "everything" I mean, of course,

  • me and you, the Earth, the Sun,

  • the hundred billion suns in our galaxy

  • and the hundred billion galaxies

  • in the observable universe.

  • Absolutely everything.

  • Now you might say, "Well, OK, but why not just look at it?

  • You know? If you want to know what I'm made of, let's look at me."

  • Well, we found that as you look back in time,

  • the universe gets hotter and hotter,

  • denser and denser, and simpler and simpler.

  • Now, there's no real reason I'm aware of for that,

  • but that seems to be the case.

  • So, way back in the early times of the universe,

  • we believe it was very simple and understandable.

  • All this complexity, all the way to these wonderful things --

  • human brains -- are a property of an old

  • and cold and complicated universe.

  • Back at the start, in the first billionth of a second,

  • we believe, or we've observed, it was very simple.

  • It's almost like ...

  • imagine a snowflake in your hand,

  • and you look at it, and it's an incredibly complicated,

  • beautiful object. But as you heat it up,

  • it'll melt into a pool of water,

  • and you would be able to see that actually it was just made

  • of H20, water.

  • So it's in that same sense that we look back in time

  • to understand what the universe is made of.

  • And as of today, it's made of these things.

  • Just 12 particles of matter,

  • stuck together by four forces of nature.

  • The quarks, these pink things, are the things that make up protons and neutrons

  • that make up the atomic nuclei in your body.

  • The electron -- the thing that goes around

  • the atomic nucleus --

  • held around in orbit, by the way, by the electromagnetic force

  • that's carried by this thing, the photon.

  • The quarks are stuck together by other things called gluons.

  • And these guys, here, they're the weak nuclear force,

  • probably the least familiar.

  • But without it the sun wouldn't shine.

  • And when the sun shines, you get copious quantities

  • of these things called neutrinos pouring out.

  • Actually, if you just look at your thumbnail --

  • about a square centimeter -- there are something

  • there are something like 60 billion neutrinos per second

  • from the sun, passing

  • through every square centimeter of your body.

  • But you don't feel them because the weak force

  • is correctly named.

  • Very short range and very weak,

  • so they just fly through you.

  • And these particles have been discovered

  • over the last century, pretty much.

  • The first one, the electron, was discovered in 1897,

  • and the last one, this thing called the tau neutrino,

  • in the year 2000. Actually just --

  • I was going to say, just up the road in Chicago. I know it's a big country,

  • America, isn't it?

  • Just up the road.

  • Relative to the universe, it's just up the road.

  • (Laughter)

  • So, this thing was discovered in the year 2000,

  • so it's a relatively recent picture.

  • One of the wonderful things, actually, I find,

  • is that we've discovered any of them, when you realize how tiny they are.

  • You know, they're a step in size

  • from the entire observable universe.

  • So 100 billion galaxies,

  • 13.7 billion light years away --

  • a step in size from that to Monterey, actually,

  • is about the same as from Monterey to these things.

  • Absolutely, exquisitely minute,

  • and yet we've discovered pretty much the full set.

  • So, one of my most illustrious forebears

  • at Manchester University, Ernest Rutherford,

  • discoverer of the atomic nucleus,

  • once said, "All science is either physics

  • or stamp collecting."

  • Now, I don't think he meant to insult

  • the rest of science,

  • although he was from New Zealand, so it's possible.

  • (Laughter)

  • But what he meant was that what we've done, really,

  • is stamp collect there --

  • OK, we've discovered the particles,

  • but unless you understand the underlying

  • reason for that pattern -- you know, why it's built the way it is --

  • really you've done stamp collecting -- you haven't done science.

  • Fortunately, we have

  • probably one of the greatest scientific achievements of the 20th century

  • that underpins that pattern.

  • It's the Newton's laws, if you want,

  • of particle physics.

  • It's called the "standard model" -- beautifully simple mathematical equation.

  • You could stick it on the front of a t-shirt,

  • which is always the sign of elegance.

  • This is it.

  • (Laughter)

  • I've been a little disingenuous, because I've expanded it out

  • in all it's gory detail.

  • This equation, though, allows you to calculate everything --

  • other than gravity -- that happens in the universe.

  • So you want to know why the sky is blue, why atomic nuclei stick together --

  • in principle, you've got a big enough computer --

  • why DNA is the shape it is.

  • In principle, you should be able to calculate it from that equation.

  • But there's a problem.

  • Can anyone see what it is?

  • A bottle of champagne for anyone that tells me.

  • I'll make it easier, actually, by blowing one of the lines up.

  • Basically, each of these terms

  • refers to some of the particles.

  • So those Ws there refer to the Ws, and how they stick together.

  • These carriers of the weak force, the Zeds, the same.

  • But there's an extra symbol in this equation: H.

  • Right, H.

  • H stands for Higgs particle.

  • Higgs particles have not been discovered.

  • But they're necessary -- they're necessary

  • to make that mathematics work.

  • So all the exquisitely detailed calculations we can do

  • with that wonderful equation

  • wouldn't be possible without an extra bit.

  • So it's a prediction --

  • a prediction of a new particle.

  • What does it do?

  • Well, we had a long time to come up with good analogies.

  • And back in the 1980s, when we wanted the money

  • for the LHC from the UK government,

  • Margaret Thatcher, at the time, said,

  • "If you guys can explain, in language

  • a politician can understand,

  • what the hell it is that you're doing, you can have the money.

  • I want to know what this Higgs particle does."

  • And we came up with this analogy and it seemed to work.

  • Well, what the Higgs does is, it gives mass to the fundamental particles.

  • And the picture is that the whole universe --

  • and that doesn't mean just space, it means me as well, and inside you --

  • the whole universe is full of something called a Higgs field.

  • Higgs particles, if you will.

  • The analogy is that these people in a room

  • are the Higgs particles.

  • Now when a particle moves through the universe,

  • it can interact with these Higgs particles.

  • But imagine someone who's not very popular moves through the room.

  • Then everyone ignores them. They can just pass through the room very quickly,

  • essentially at the speed of light. They're massless.

  • And imagine someone incredibly important

  • and popular and intelligent

  • walks into the room.

  • They're surrounded by people, and their passage through the room is impeded.

  • It's almost like they get heavy. They get massive.

  • And that's exactly the way the Higgs mechanism works.

  • The picture is that the electrons and the quarks

  • in your body and in the universe that we see around us

  • are heavy, in a sense, and massive,

  • because they're surrounded by Higgs particles.

  • They're interacting with the Higgs field.

  • If that picture's true,

  • then we have to discover those Higgs particles at the LHC.

  • If it's not true -- because it's quite a convoluted mechanism,

  • although it's the simplest we've been able to think of --

  • then whatever does the job of the Higgs particles

  • we know have to turn up

  • at the LHC.

  • So that's one of the prime reasons we built this giant machine.

  • I'm glad you recognize Margaret Thatcher.

  • Actually, I thought about making it more culturally relevant, but --

  • (Laughter)

  • anyway.

  • So that's one thing.

  • That's essentially a guarantee of what the LHC will find.

  • There are many other things. You've heard

  • many of the big problems in particle physics.

  • One of them you heard about: dark matter, dark energy.

  • There's another issue,

  • which is that the forces in nature -- it's quite beautiful, actually --

  • seem, as you go back in time,

  • they seem to change in strength.

  • Well, they do change in strength.

  • So the electromagnetic force, the force that holds us together,

  • gets stronger as you go to higher temperatures.

  • The strong force, the strong nuclear force, which sticks nuclei together,

  • gets weaker. And what you see is the standard model --

  • you can calculate how these change -- is the forces --

  • the three forces, other than gravity --

  • almost seem to come together at one point.

  • It's almost as if there was one beautiful

  • kind of super-force, back at the beginning of time.

  • But they just miss.

  • Now there's a theory called supersymmetry,