The Large Hadron Collider (LHC) is the world’s largest particle collider, recently built by CERN near the Swiss-French border. Having started up in September but then closed soon thereafter because of technical problems, it is not expected to reopen until July. The collider is designed to study particles produced by the collision of two beams of protons traveling in opposite directions at extremely high energies, and it may very well provide us with data that could revolutionize our understanding of physics.
A concern has been raised by a number of observers that these collisions could produce tiny black holes that could literally swallow up the Earth. I initially regarded such speculations with considerable skepticism, having seen how parallel alarmist fears have greeted just about every major technological advance since at least the beginning of the Industrial Revolution. No doubt, when Prometheus first discovered fire, there were critics who were concerned that he might inadvertently ignite a conflagration that would engulf the entire world in holocaust.
In the last few days, however, I’ve come upon two articles that seem to give some serious weight to the concerns in this case. When the black holes issue was first raised, calculations were produced predicting that any such black holes would decay practically immediately, in a tiny fraction of a second, long before any damage could be done. A recent article (http://arxivblog.com/?p=1136), however, discusses some more recent revised calculations that suggest that they could possibly survive for longer than a second, perhaps even for minutes. Although most scientists still don’t see them as a significant danger, they agree that the danger is a number of order of magnitudes greater than previously estimated. Furthermore, the very fact that the original calculations seem to have been incorrect leads one to wonder just how well the risks are understood.
The second article (http://www.newscientist.com/article/mg20126926.800-how-do-we-know-the-lhc-really-is-safe.html?page=1) raises an important question about the whole probability calculation, which originally estimated that the probability of a major disaster was of the order of 10**-9. Although I don’t agree with the mathematical methodology of the article (it suggests a formula that purports to assign numerical values to a kind of probabilities to which numerical values don’t apply), I think the underlying idea is valid. The underlying idea is that the calculations are predicated on a particular view of the physics involved, and there remains a very real possibility that this view is mistaken, so that we may be seriously underestimating the probability of catastrophe.
Even if one were to concede that the probability of disaster is miniscule (and it seems far from clear that such is the case), the magnitude of such a disaster would be beyond any other disaster imaginable, which I think compels us to look at this issue VERY carefully. It’s not my intention here to minimize discussions about global warming, but where those who are most fearful of GW speak of the destruction of the planet, they probably don’t mean it in the sense of annihilating the entire planet, perhaps in a fraction of a second.
I’d be very interested to see the opinions of others on this issue, particularly those who know more about the physics than I.
