You can easily guess why some people consider these experiments dangerous. The general consensus among scientists was that it’s safe. But not everyone is sure. It’s almost like with first tests of nuclear weapons. Edward Teller, Hungarian scientist, was concerned that nuclear testing in atmosphere could ignite it, and burn everything (I mean EVERYTHING). The speculation was later refuted by more-less mathematical proof, that it’s not possible. I would say that in the end, LHC can be as important for advances of human race as was Manhattan Project. Yes, I know that they created atomic bomb, but by doing so they started revolution in nuclear energy and certainly other research areas that were not possible before.
Anyway, read at least the Wikipedia article about LHC. It’s really worth it. Or even better, I think that BBC had a LHC documentary, go watch it.
Note: I will finally have time to write some more posts today hopefully. I was too busy living my life for the past week