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<div class="rich-text">(This video is no longer available for streaming.) Explore the construction of the mother of all particle accelerators: the Large Hadron Collider at CERN, the international particle physics lab near Geneva, Switzerland. In this video, physicist David Wark reports on the ambitious goals of this 16-mile-long circular racetrack. Designed to smash protons together at near-light speed, CERN promises astonishing new discoveries about matter.
</div>

Go beneath the Alps to explore the biggest particle accelerator in the world, the Large Hadron Collider.

<div class="rich-text">Go beneath the Alps to explore the biggest particle accelerator in the world, the Large Hadron Collider.</div>

Beneath the Alps, the mother of all particle accelerators nears completion.

CERN

Physics & Math

<div class="rich-text"><h3>
 CERN
</h3>

 PBS Airdate: July 10, 2007



 NEIL
DEGRASSE TYSON:
 
 In the movies,
crazy scientists who build time machines are always obsessing about power, like
it takes so many jiggawatts of electricity to get the thing to work.


 Well,
a bunch of real scientists have been working for years on one giant experiment,
trying to create exotic particles that haven't existed in the universe
for 14 billion years, back to the Big Bang itself.


 Physicist
and correspondent David Wark reports that, in a way, it's a giant time
machine. Just like in the movies, it's all about energy.



 DAVE
WARK:
 
 (Correspondent)
 
 :
 
 You'd never guess that, hidden beneath
these French mountains, an army of workers is underground, constructing the
biggest and most complex machine on Earth.


 It's
a project that's got physicists around the world brimming with
anticipation.



 PETER
FISHER:
 
 It's
a big step, this is a big time.



 MEENAKSHI
NARAIN:
 
 We may find things which nobody
has ever thought of, or told us before.



 STEVE
AHLEN
 
 (Boston University)
 
 :
 
 It's a real adventure because we don't
know if it's going to work.



 DAVE WARK:
 
 The
goal of this giant construction project is nothing less than to find the basic
building blocks of the universe.



 MEENAKSHI
NARAIN:
 
 The basic quest of particle
physics is, "What is the world made of? Do we know everything? Do we know
all the constituents of matter? Do we have them all?"



 DAVE WARK:
 
 Scientists have already found a whole carnival of
subatomic particles that make up the universe.



 MEENAKSHI
NARAIN:
 
 List some names.



 STEVE
AHLEN:
 
 Matter as we know it today...



 PETER
FISHER:
 
 There
are protons, neutrons. That's what we're made of.



 MEENAKSHI
NARAIN:
 
 The top quark...



 STEVE
AHLEN:
 
 ...bottom
quark



 MEENAKSHI
NARAIN:
 
 The up...



 STEVE
AHLEN:
 
 ...and the down quarks.



 MEENAKSHI
NARAIN:
 
 ...the charm quark, the
strange quark...



 STEVE
AHLEN:
 
 There was a time when we just named everything something silly.



 PETER
FISHER:
 
 There
are pions, kaons...



 MEENAKSHI
NARAIN:
 
 ...W-bosons, Z-bosons.



 PETER
FISHER:
 
 ...five
different upsilon particles...lambdas...



 STEVE
AHLEN:
 
 ...gluons for the strong force...



 PETER
FISHER:
 
 ...omegas,
sigmas.



 MEENAKSHI
NARAIN:
 
 ...muons.



 STEVE
AHLEN:
 
 Who ordered that?



 PETER
FISHER:
 
 And
my favorite particle is the tau.



 DAVE WARK:
 
 This panoply of particles is called The Standard
Model, and it's our best picture of what the universe is made of.


 But
as dazzling as it is, we know that the carnival is incomplete. There have to be
other hidden particles out there, and we need a new experiment to find them.


 Normally
physicists don't get to ride in helicopters, but today we want to see the
world's largest experiment, and up here's really the only place you
can get a sense of the scale.


 Below
me is the construction site at CERN, a particle physics lab. The new experiment
is so big it stretches from the mountains in France, across the border, to the
Geneva Airport in Switzerland. That's because the main part consists of a
circular tunnel, 16 miles around. The tunnel is home to the world's
biggest, most powerful particle accelerator ever, called the Large Hadron
Collider or LHC. Because it's so big, LHC will let us probe deeper into
the stuff of the universe than we've ever gone before.


 This
tunnel is being filled with giant electro-magnets, and, in fact, you can see
some of them on the ground right there.


 This
is my stop.


 Each
tubular magnet costs close to a million dollars, and the LHC will need more
than 1,600 of them.


 So
what is this?



 MARTA
BAJKO
 
 (Accelerator Technology Group, CERN)
 
 :
 
 This is the magnet; this is the magnet which is
inside this big blue tube.



 DAVE WARK:
 
 The magnets are designed to keep those tiny parts
of an atom called protons flowing in a narrow beam through the tunnel. When
they are all connected together into a ring, the magnets will create a 16-mile
racetrack for protons.


 In
the ring, the powerful magnetic fields force the protons to go round in a
circle, and each time they go round they get a little kick from an electric
field, so they go faster and faster until, eventually, they are traveling
almost at the speed of light.



 MARTA
BAJKO:
 
 In
fact, the particles, they are traveling in these two tubes. In one of the tubes
the particles are traveling in one direction, in the other tube in the opposite
direction.



 DAVE WARK:
 
 So there's actually two beams of particles,
going in opposite directions?



 MARTA
BAJKO:
 
 Exactly.
Yes.



 DAVE WARK:
 
 One beam going one way and one beam going the
other way. And there are two beams because you are going to collide them?



 MARTA
BAJKO:
 
 Exactly.



 DAVE WARK:
 
 This is a technique that's familiar to
physicists. A proton traveling close to the speed of light, although absolutely
tiny, will carry a lot of energy. Two of them traveling in opposite directions
will carry twice the energy. Make them collide and most of that energy can be
released in a tiny, but powerful explosion.


 With
enough energy, the explosion should create fundamental particles that
we've never seen before. If that happens, it'll be in a tiny region
smack in the center of a vast underground cavern.


 This is one of the four places around the ring
where the two beams will actually collide. One beam will come from a tiny beam
pipe, from the middle of that hole over there, and fly over my head. The second
beam comes through that hole over there, and high up over my head, in the
middle of the cavity, the two protons will collide.


 Now,
we're colliding two tiny little protons. Why do we need this vast cavern
to find out what happens? Well, in order to detect if any new particles have
been created in a collision, researchers have to fill this cavern with some of
the most complex scientific instruments ever created.


 The
one here is called CMS.


 This
is one end of the vast CMS detector; the whole detector consists of a series of
these plates, each one of which is instrumented with thousands of detectors you
can see up here. As we move down we see a large number of these which will all
be slid together to make the final detector. No space at all is wasted. This
big hole looks like a hole in the detector, but in fact the hole in those
detectors is filled by these detectors.


 Different
detectors pick up different kinds of particles, and sandwiched together
they'll create a single enormous cylinder which completely surrounds the
point where the protons collide. That's important because, as the
particles fly away from the collision through the detector, they will leave
tracks which form a kind of fingerprint.


 It's
by analyzing these fingerprints that scientists should be able to tell if a new
particle was briefly created at the moment of collision.



 PETER
FISHER:
 
 That's
why the experiments are hugely complicated. They have to identify all the
things that come out of two protons that hit.



 STEVE
AHLEN:
 
 The LHC experiments are by far the most difficult that have ever been
done in high energy physics, and maybe any experiment.



 DAVE WARK:
 
 In fact, the experiments are so complicated it
takes physicists from dozens of countries to pull them off.



 LHC
TEAM MEMBER 1:
 
 I'm from Switzerland.



 LHC
TEAM MEMBER 2:
 
 I'm from Belgium.



 LHC
TEAM MEMBER 3:
 
 ...sono Italiana,
Toscana.



 LHC
TEAM MEMBER 4:
 
 ...France.



 LHC
TEAM MEMBER 5:
 
 ...Japan.



 LHC
TEAM MEMBER 6:
 
 ...Austin, Texas.



 LHC
TEAM MEMBER 7:
 
 ...Russian.



 LHC
TEAM MEMBER 8:
 
 ...UK.



 LHC
TEAM MEMBER 9:
 
 ...California.



 LHC
TEAM MEMBER 10:
 
 I'm from Senegal.



 LHC
TEAM MEMBER 11:
 
 ...New Jersey.



 LHC
TEAM MEMBER 12:
 
 ...Colombia.



 LHC
TEAM MEMBER 13:
 
 ...India, from Bombay.



 LHC
TEAM MEMBER 14:
 
 ...from Germany.



 LHC
TEAM MEMBER 15:
 
 ...Argentina.



 LHC
TEAM MEMBER 16:
 
 I'm from Togo, West
Africa.



 LHC
TEAM MEMBER 17:
 
 I'm from Brazil.



 LHC
TEAM MEMBER 18:
 
 And I'm from the
Czech Republic.



 JIM
BENSINGER
 
 (Brandeis University)
 
 :
 
 You meet people from all over the world. You talk
with them; you get their point of view; you exchange ideas. They all tend to be
physicists, so it's not that wide, but I find that's exciting. If
the rest of the world worked the way we do, we'd have far fewer problems.



 DAVE WARK:
 
 One problem they do have is analyzing the vast
mountain of data that the LHC is going to produce, because, when it's
running, it'll create about a billion proton collisions a second. And
it'll be running 24/7.



 TEJINDER
VIRDEE:
 
 We get 40 million megabytes of
data created every second.



 DAVE WARK:
 
 Forty million megabytes, 40,000 gigabytes, or
that would be 1,000 large discs for your home computer every second.



 TEJINDER
VIRDEE:
 
 Yes, it's mind boggling. The
amount of data that we are generating in one year is 10 times bigger than all
the World-Wide-Web-stored data.



 DAVE WARK:
 
 In fact, the World Wide Web was invented here at
CERN to analyze the results of earlier experiments.


 But
the LHC has so much more data, it will need the power of the Web's
successor, something called "the GRID." Using millions of computers
around the world, the GRID will turn high-speed computing power into just
another commodity, like music or telephone service, that, someday soon,
everyone will be able to buy online.


 It's
all part of a quest to understand the world in minute detail.


 One
mystery scientists would love to solve is why some of the particles now
whizzing around the universe have mass.



 STEVE
AHLEN:
 
 The fact is, from a physicist's point of view, from a
philosopher's point of view, from an observational point of view, mass is
actually quite mysterious.



 DAVE WARK:
 
 In our best theory of matter, the Standard Model,
all the really fundamental particles are like photons—the particles of
light—in that they have no intrinsic mass.


 But
we know that objects in the real world have mass, and scientists know that
particles like protons and electrons also have mass. So where does that mass
come from?



 PETER
FISHER:
 
 Why
do particles have different masses? And why do they have mass at all? Mass is
not something that emerges naturally from a theory.



 MEENAKSHI
NARAIN:
 
 We basically do not understand why
some particles got mass and others didn't. What happened? What gave mass?



 DAVE WARK:
 
 The leading idea for explaining mass is something
called the Higgs field, a field which we believe pervades all of space and
which the fundamental particles interact with.


 The
Higgs field is like cosmic cotton candy; it sticks to everything. And,
according to this idea, it's actually that stickiness that gives
particles their mass.


 If
the Higgs field, along with a Higgs particle, really exists, then the Large
Hadron Collider should find it. And that would be a triumph for the Standard
Model.


 But
since the LHC will take the particle hunt to a whole new level, many physicists
are hoping it will uncover types of matter we've never even dreamed of.



 MEENAKSHI
NARAIN:
 
 The best case, in my mind: we do
not find the Higgs particle, and we find a whole new set of new particles.



 STEVE
AHLEN:
 
 I don't really care what we find. You know, I just want to go off
there and look at something and see something no one's ever seen before.
That's what motivates me.



 PETER
FISHER:
 
 It's
just a voyage of discovery. It's looking out into the cosmos and trying
to see where we fit in it.
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