You can sleep easy in the knowledge that the world's most powerful particle smasher, the Large Hadron Collider, will not gobble us all up in the middle of the night. So says a new safety assessment released by CERN, the European Organization for Nuclear Research, based near Geneva, Switzerland .

The lab hopes this will quash relentless rumours that the LHC could create Earth-obliterating particles. Favourite examples are mini black holes and ravenous "killer strangelets" that could swallow our...