Cern in Geneva is preparing to start up the Large Hadron Collider (LHC), which will fire particles together at near the speed of light, recreating in miniature the energy released in the Big Bang. But scientists have been besieged by anxious members of the public concerned that the LHC will create a black hole or cataclysmic cosmic rays. Do you think the atom smasher will destroy the planet or merely reveal some quaintly named subatomic particle?