New York's Long Island, physicists are preparing to travel back to the dawn of the universe. In a few weeks their time machine, buried beneath the department of energy's Brookhaven National Laboratory, will begin stripping gold atoms of their electrons and accelerating them to 99.995 per cent of the speed of light. Then it will smash pairs of the atoms together with such violence that the collissions will generate temperatures 10,000 times hotter than the sun.