Sit tight, a bigger bang is coming...

THE vast new Cern particle collider has only just hummed into life, but physicists are already drawing up plans for a still larger machine to answer the questions even Albert Einstein was unable to resolve.

The International Linear Collider (ILC) would be a machine up to 31 miles long, comprising two giant “guns” that would accelerate electrons and particles of antimatter called positrons to near-light speeds before smashing them together.The results could open up some of the hottest topics in physics, such as the existence of extra dimensions, the origins of gravity and even how the big bang – the event that created the universe – happened.

“The ILC would build on the work of Cern’s new Large Hadron Collider [LHC],” said Brian Foster, professor of experimental physics at Oxford University and European director of the project. “The LHC smashes protons together to discover new particles but also generates lots of debris that obscures the fine detail. The ILC would be a much cleaner machine and tell us far more about their real nature.”

Physicists around the world have spent about £150m on designs for the new machine, nicknamed “Einstein’s telescope”, since the project was set up three years ago. About £10m has come from Britain.

This weekend 80 researchers from many countries gathered at Emmanuel College, Cambridge, to study plans for the giant detectors that would investigate the collisions. Mark Thomson, Cambridge’s newly appointed professor of experimental particle physics, who was among those present, said the new machine would cost about £4 billion, with a final design expected around 2012.

“Physics theory suggests the LHC will find a subatomic particle called the Higgs boson, but if it does, this will raise many new questions,” he said. “It would be a completely bizarre and new form of matter and we would need the ILC to really pin down its properties.”

Such a machine would have to be huge – and very different from the circular LHC. When accelerated along a curved path, electrons and positrons lose much of their energy as they emit bursts of x-rays.

The ILC would need to be completely straight, with two huge linear accelerators pointing at each other and collisions happening at the point where their respective particle beams meet. They would at first be 11 miles long but could be extended to 15½ miles each. The accelerators would hurl 10 billion electrons and positrons at each other every second.

When matter meets antimatter, the particles annihilate each other, releasing a burst of energy that is converted into yet more particles plus radiation. The ILC’s beams would generate around 14,000 such collisions each second, possibly creating new combinations of particles that could answer fundamental questions.

Physicists have dreamt of such a machine for decades but the technology needed to accelerate electrons and positrons to such high speeds has been developed only in the past few years. It works by sending massive bursts of radio waves into the tunnels. The particles can lock onto these waves and “surf” them, becoming faster with each successive wave.

Such a machine might be able to resolve some of the questions raised by Einstein’s theories of relativity. The problem for Einstein, still unresolved, was that he could not reconcile the laws of the very large with the laws of the very small.

The world of atoms and particles is dominated by the three forces of electromagnetism and strong and weak nuclear forces.

On the scale of planets and stars, however, a fourth force, gravity, is in charge. Einstein’s problem was that the way gravity works seemed mathematically impossible to reconcile with the other three.

Physicists believe, however, that immediately after the big bang just one force existed. As the early universe cooled, this split into the four forces seen today. The ILC team hopes to recreate the elemental single force and find how it gave rise to its four successors. It could also shed light on the nature of the mysterious dark matter thought to constitute more than 90% of the universe.