40km tunnel will try to unravel secrets of universe

Details of a giant machine for discovering the secrets of the universe were revealed yesterday by scientists who believe the massive device could revolutionise how we understand the cosmos.

Details of a giant machine for discovering the secrets of the universe were revealed yesterday by scientists who believe the massive device could revolutionise how we understand the cosmos.

An international panel of particle physicists has decided that the high-energy linear collider - a £3bn machine for smashing matter against antimatter - will use revolutionary superconducting technology to shed light on the origin and nature of the universe. Plans for the International Linear Collider have still to be finalised but scientists hope that construction of the underground machine will begin in six years.

The collider will be housed in a dead-straight tunnel up to 40km long. It will set a precedent by becoming the first truly globally owned instrument built by all the major countries of the world.

By colliding pencil-thin beams of electrons and positrons - the antimatter equivalent of electrons - scientists believe they will be able to answer some of the greatest unsolved mysteries of the universe, said Neil Calder, director of communications at the Stanford Linear Accelerator Centre in California.

"In the last 10 years there has been a revolution in our concept of the universe and the realities of our new knowledge are very much stranger than could be have been imagined," he said.

Last year, physicists accurately measured for the first time how the universe is composed. They found that only 4 per cent of it was made up of visible atoms, with the rest being mysterious dark matter and dark energy - neither of which entities can be seen.

"The implications of this new understanding are enormous. We and everything we can see with our most powerful instruments make up only 4 per cent of the universe," Dr Calder said. "We are a tiny minority. The rest is waiting to be discovered... The linear collider is the key to understanding this weird and wonderful universe that we inhabit," he said.

Professor Brian Foster of Oxford University said that the linear collider will be fully integrated with existing atom smashers such as the Large Hadron Collider currently being built at the Cern high-energy physics centre in Geneva.

"The linear collider will take our science into completely new areas which will hopefully reveal new and exciting physics, addressing the 21st century agenda of compelling questions about dark matter and dark energy, the existence of extra dimensions and the fundamental nature of matter, energy, space and time," Professor Foster said.

Professor George Kalmus of the Rutherford Appleton Laboratory in Oxfordshire said that the linear collider was needed because existing atom smashers could only take the understanding of sub-atomic physics so far.

"We're at a point where we understand a great deal of how the world is put together, but we certainly don't understand it all, such as what is the origin of mass," said Professor Kalmus, who is a member of the international panel which decided on the technology to be used in the linear collider.

Professor Kalmus said that when quantum mechanics was first discussed 80 years ago by scientists such as Albert Einstein, no one could have predicted that this esoteric area of physics would eventually form the basis of all modern microelectronics. "When we understand things at a deeper level, which we will with the linear collider, we get an insight into other areas," he said.

Spending £3bn on a single machine would almost certainly generate practical spin-offs, although no one at this stage can predict what these would be, Professor Kalmus said. "If we could foresee what will come out of this, the case for building it would be easy to make," he said.

Germany, Japan and the United States are leading contenders for the site of the new machine. Millions of pounds are being spent on researching the technology of the linear collider but a final decision on whether to go ahead and build it is not likely for another three or five years.