The problem with all of the doomsday prophecies surrounding the LHC is that they are all the same ones that were brought out every other time a particle accelerator was about to be completed. Theoretically, it is possible that we destroy the universe with the LHC but a possibility is far from a high probability. Personally, I have been waiting on the edge of my seat for this since the first time I heard about its construction 7 or so years ago.