I don’t think any real scientist would ever make a statement like “this is impossible”, or “this will never happen” — it is always “this is extremely unlikely”, with a qualifying “if current knowledge and theory holds”. It seems to be a fundamental property of science that we can never prove that something is true, but can only falsify hypotheses.
So, what is this “no conceivable danger” conclusion in the 22-page “Review of the Safety of LHC Collisions” November 2008 publication by the LHC Safety Assessment Group? How does one make any claims at all about what will not happen in an unexplored regime of experiment/theory?
The fine print that resolves the dilemma is that “unexplored regime” is not true. Homo sapiens may be patting ourselves on our backs for finally anticipating life at 10 TeV center-of-mass energy, but the universe has been ahead for some number of years equal to 1031 LHC experiments — and at a rate of 1013 LHC’s per second. Now we note that the universe still exists (as far as we can tell), planets and stars don’t spontaneously turn into black holes (as far as we can tell), and even the Earth has apparently survived 100 000 LHC-like experiments i.e. all those cosmic rays that the cosmos bestows upon us.
Could the 100 001-st time be particularly unlucky? It’s not impossible, but we probably have to work much harder to increase our ratings as a threat to reality.
This post was inspired by an interesting comment from a reader, who asked “when will the experiment finish?” After getting all excited about the lifetime of CMS and proposed Super-LHC upgrades — and hitting the “send” button — I suddenly realized that the concern was probably “hey, when will you stop gambling with all our lives?”, and not so much “hey, how long does a cool experiment like this take?”
I was going to mention that I believe politicians and military to be more active threats to humanity than the unbounded (but not unregulated) curiosity of scientists. But then, it can be argued that destroying an ecosystem is still a lesser crime than annihilating the planet and perhaps the universe too, while we’re at it.