Five Particles

Simon Singh examines the significance of subatomic particles.

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01The Electron2008090820101011

Simon Singh examines the significance of five subatomic particles in five programmes In the first programme he tells the story of the discovery of the electron.

Just over a century ago, British physicist J.J.

Thomson experimenting with electric currents and charged particles inside empty glass tubes, showed that atoms are divisible into indivisible elementary particles.

But how could atoms be built up of these so called "corpuscles"? An exciting 30 year race ensued, to grasp the planetary model of the atom with its orbiting electrons, and the view inside the atom was born.

Whilst the number of electrons around the nucleus of an atom determines the chemistry of all elements, the power of electrons themselves has been harnessed for everyday use: electron beams for welding,cathode ray tubes and radiation therapy.

Producer Adrian Washbourne.

Simon Singh on the significance of five subatomic particles, starting with the electron.

British physicist JJ Thompson's experiments with electric currents showed that atoms are divisible into elementary particles.

But how has the power of electrons been harnessed for everyday use?

02The Quark2008090920101012

Simon Singh examines the significance of five subatomic particles 2) The Quark.

"Three Quarks for Master Mark! Sure he hasn't got much of a bark." James Joyce's Finnegans Wake left its mark on modern physics when physicist Murray Gell Mann proposed this name for a group of hypothetical subatomic particles that were revealed in 1960 as the fundamental units of matter.

Basic particles, such as protons and neutrons, it seems, are made up of even more basic units called quarks that make up 99.9% of visible material in the universe.

But why do we know so little about them? Quarks have never been seen as free particles.

They are inextricably bound together by the Strong Force that in turn holds the atomic nucleus together.

This is the hardest of Nature's fundamental forces to crack, but recent theoretical advances mean that the properties of the quark are at last being revealed.

Producer: Adrian Washbourne.

Quarks comprise virtually all visible material, but why do we know so little about them?

Quarks comprise virtually all visible material in the universe, but why do we know so little about them? They have never been seen as free particles, but recent theoretical advances are finally beginning to reveal their properties.

03The Antiparticle2008091020101013

Simon Singh looks at the stories behind the discovery of five of the universe's most significant subatomic particles.

3) The Antiparticle.

It appears to be the stuff of science fiction.

Associated with every elementary particle is an antiparticle which has the same mass and opposite charge.

Should the two meet and combine, the result is annihilation - and a flash of light.

Thanks to mysterious processes that occurred after the Big Bang there are a vastly greater number of particles than anti-particles.

So how could their elusive existence be proved? At CERN particle physicists are crashing together subatomic particles at incredibly high speeds to create antimatter, which they hope will finally reveal what happened at the precise moment of the Big Bang to create the repertoire of elementary particles and antiparticles in existence today.

Producer: Adrian Washbourne.

Every particle has an antiparticle.

Should the two combine, the result is annihilation.

Every elementary particle has an antiparticle.

Should the two meet and combine, the result is annihilation.

So where are all the antiparticles? At CERN, the European research centre in Geneva, physicists are crashing together subatomic particles at incredibly high speeds, hoping to create anti-matter and find the answer.

04The Neutrino2008091120101014

Simon Singh looks at the stories behind the discovery of five of the universe's most significant subatomic particles.

4) The Neutrino.

It's the most populous particle in the universe.

Millions of these subatomic particles are passing through each one of us.

With no charge and virtually no mass they can penetrate vast thicknesses of matter without any interaction - indeed the sun emits huge numbers that pass through earth at the speed of light.

Neutrinos are similar to the more familiar electron, with one crucial difference: neutrinos do not carry electric charge.

As a result they're extremely difficult to detect.

But like HG Wells' invisible man they can give themselves away by bumping into things at high energy and detectors hidden in mines are exploiting this to observe these rare interactions.

But they can give themselves away by bumping into things at high energy, and detectors hidden in mines are exploiting this to see inside stars for the very first time

Producer: Adrian Washbourne

The most common particle in the universe continuously passes through each of us.

is the most common particle in the universe.

Millions of these virtually undetectable subatomic particles are continuously passing through each of us.

However, they can betray their presence by bumping into things at high energy.

Detectors hidden in mines are exploiting this to observe these rare interactions.

05 LASTThe Next Particle20080912

A symmetric partner to all the known particles could be the answer to uniting them and their interactions under one grand theoretical pattern of activity.

But how do researchers know where to look for such phenomena and how do they know if they find them?