The worlds of physics and computing naturally find their paths crossing on numerous occasions (the undertanding of how tiny circuits behave has paved the way for todays powerful CPUs), so the switch-on of the Large Hardon Collider at Cern on the Swiss-French border will probably be of interest to some of you. The £5bn (nearly $9bn) machine was started for the first time today, with two beams of protons being fired around the 27km tunnel. These were simply test beams fired around the circuit in clockwise and anti-clockwise directions. Scientists aren't sure when exactly they will run the first collisions (where the beams smash into each other in an attempt to create conditions simlar to those found a short time after the big bang), but these could come within the next few days (albeit it at low energies). So you still have time to worry about all the highly improbable consequences of what could go wrong yet.