Spectators look at the ATLAS detector construction (a Toroidal LHC Apparatus) at the CERN (Centre Europeen de Recherche Nucleaire) near Geneva, Switzerland, Thursday, May 31, 2007. The detector will be placed around the large hadron collider (LHC), CERN's highest energy particle accelerator. ATLAS is a general-purpose detector designed to measure the broadest possible range of particles and physical processes that could result from the collision of the proton beams within the LHC. A pilot run of the LHC is scheduled for summer 2007. (KEYSTONE/Martial Trezzini)

Spectators look at the ATLAS detector construction (a Toroidal LHC Apparatus) at the CERN (Centre Europeen de Recherche Nucleaire) near Geneva, Switzerland, Thursday, May 31, 2007. The detector will be placed around the large hadron collider (LHC), CERN's highest energy particle accelerator. ATLAS is a general-purpose detector designed to measure the broadest possible range of particles and physical processes that could result from the collision of the proton beams within the LHC. A pilot run of the LHC is scheduled for summer 2007. (KEYSTONE/Martial Trezzini)

View of the LHC (large hadron collider) in its tunnel at CERN (European particle physics laboratory) near Geneva, Switzerland, Thursday, May 31, 2007. The LHC is a 27-kilometre-long underground ring of superconducting magnets housed in this pipe-like structure or cryostat. The cryostat is cooled by liquid helium to keep it at an operating temperature just above absolute zero. It will accelerate two counter-rotating beam of protons to an energy of 7 tera electron volts (TeV) and then bring them to collide head on. Several detectors are being built around the LHC to detect the various particles produced by the collision. A pilot run of the LHC is scheduled for summer 2007. (KEYSTONE/Martial Trezzini)

**FILE**This March 22, 2007 file photo, shows the magnet core of the world's largest superconducting solenoid magnet (CMS, Compact Muon Solenoid) at the European Organization for Nuclear Research (CERN)'s Large Hadron Collider (LHC) particle accelerator, which is scheduled to be switched on in November, in Geneva, Switzerland. Some 2,000 scientists from 155 institutes in 36 countries are working together to build the CMS particle detector. (AP Photo/Keystone, Martial Trezzini, file)

Spectators look at the ATLAS detector construction (a Toroidal LHC Apparatus) at the CERN (Centre Europeen de Recherche Nucleaire) near Geneva, Switzerland, Thursday, May 31, 2007. The detector will be placed around the large hadron collider (LHC), CERN's highest energy particle accelerator. ATLAS is a general-purpose detector designed to measure the broadest possible range of particles and physical processes that could result from the collision of the proton beams within the LHC. A pilot run of the LHC is scheduled for summer 2007. (KEYSTONE/Martial Trezzini)

**ADVANCE FOR SUNDAY, JUNE 29--FILE** In this March 22, 2007 file photo, the magnet core of the world's largest superconducting solenoid magnet (CMS, Compact Muon Solenoid) at the European Organization for Nuclear Research (CERN)'s Large Hadron Collider (LHC) particle accelerator, which is scheduled to switch on in November 2007, in Geneva, Switzerland. Some 2000 scientists from 155 institutes in 36 countries are working together to build the CMS particle detector. (AP Photo/Keystone, Martial Trezzini, file)

Employees inspect the ATLAS detector construction (a Toroidal LHC Apparatus) at the the CERN (Centre Europeen de Recherche Nucleaire) near Geneva, Switzerland, on Thursday, May 31, 2007. The detector will be placed around the large hadron collider (LHC), CERN's highest energy particle accelerator. ATLAS is a general-purpose detector designed to measure the broadest possible range of particles and physical processes that could result from the collision of the proton beams within the LHC. A pilot run of the LHC is scheduled for summer 2007. (KEYSTONE/Martial Trezzini)

View of the LHC (large hadron collider) in its tunnel at CERN near Geneva

French police have arrested a scientist working at the giant European CERN atom smasher laboratory. He is being held on suspicion of being linked to al Qaida.

The physicist was one of more than 7,000 working at the European Organisation for Nuclear Research whose massive underground particle accelerator spans the French and Swiss borders.

CERN said he was assigned to analysis projects under contract with an outside institute.

The man had no contact with anything that could be used for terrorism, said the organisation.

The LHCb experiment where he worked is the smallest of a series of installations along the 17-mile circular tunnel under the borders.

The projects are aimed at making discoveries about the makeup of matter when the Large Hadron Collider - the world largest atom smasher - starts collecting data later this year or early next year.

LHCb is an experiment set up to explore what happened after the Big Bang that allowed matter to survive and build the universe we inhabit today.

The Big Bang was a vast explosion that scientists theorise was the beginning of the universe 14 billion years ago.

The European laboratory has been working for years to build the collider.

The man, who has not been named, was arrested yesterday in the eastern French city of Vienne accused of links to terrorist organisations in Algeria.

The case is being handled by the anti-terrorist section of the Paris prosecutor's office.

Many of the scientists at the laboratory, whether or not they are employees of the organisation or of other institutes around the world, live in France, and about half the operation is on French territory.

The man has been working on analysis projects with the LHCb experiment at CERN since 2003.

"None of our research has potential for military application, and all our results are published openly in the public domain," the organisation said in a statement.

The Big Bang Machine 1/5

The Large Hadron Collider: End of the world, or God's own particle?

A bewildered Cole Moreton goes in search of the science behind the spin...

Yes, but what is it? That has been many people's reaction to the furore over the Large Hadron Collider, due to be switched on this Wednesday. The biggest, most expensive experiment in history is attracting both scientific hyperbole and hysteria. Some say it will reveal the universe's secrets and lead to the elusive Theory of Everything. A few fear that unleashing unimaginable power beneath the Swiss countryside will result in the end of the world. But how? And what do all these words mean?

Large

Is an understatement. A giant circular tunnel, with several loops, stretches for 27km under the land between France and Switzerland. One of its experimental chambers is bigger than the nave of Westminster Abbey.

Hadron

The name for one of the types of particle that make up an atom. These tiny bits of energy will be propelled by giant magnets around the tunnel circuit at almost the speed of light.

Collide

Is what they will do when they meet other hadrons being beamed in the opposite direction, at the same great speed. The resulting explosion will create 100,000 times more heat than the sun, apparently. Thankfully, it will only happen for a moment, in an area a billion times smaller than a speck of dust.

Cern

Pronounced "sern". The French acronym for the European Organisation for Nuclear Research, which built the £5bn collider. The money came from 20 countries, including Britain, which has played a leading role.

The Big Bang

Is what they are trying to recreate. Or rather what happened a trillionth of a second after the universe was created by an explosion, 13.7 billion years ago. For that tiny moment, it is believed everything was molten plasma. This cooled to create everything we see around us. The hope is that by remaking the moment, in miniature, the scientists will be able to see things that are invisible now.

The God Particle

Big name, very small thing; and the first great discovery they hope to make. It is believed we have only detected a quarter of the particles in everything. We don't, for example, know why things have mass. (To get a feeling for what that is, hit yourself over the head with an inflatable hammer, then a real one. The one that hurts has more mass.) In 1964 Professor Peter Higgs of Edinburgh University predicted an unseen particle that provided mass (its official name is a Higgs boson). The hope is it will be detected for the first time. Other possible revelations include so-called dark matter, which in theory "stretches through space like an invisible skeleton".

The Theory of Everything

The Holy Grail of science. A unifying theory providing one explanation for the forces at work in the natural world, from the nucleus of an atom to the movements of the planets. Sounds like alchemy to non-scientists, but some very respectable minds believe it is possible, and that the collider may show the way.

The End of the World

Some scientists, on the other hand, went to the European Court for Human Rights to try to stop the collider being turned on. They fear it may create a black hole – which would certainly violate our rights by sucking the planet into... well we don't really know. Professor Sir Chris Llewellyn Smith of Cern says: "The chance we produce a black hole is minuscule." Which is not all that reassuring. But he adds: "Even if we do, it can't swallow up the Earth." It would be too small, and disappear in moments.

Belfast Telegraph