LHC Facts

You ask good questions. You ask me to explain the sources for the following chain of dangerous events:

1) A black hole is created at CERN, as predicted by some theories.

The following two papers predict black holes at CERN. These were followed by dozens of other papers making the same prediction.

Savas Dimopoulos and Greg Landsberg, “Black holes at the Large Hadron Collider,” Physical Review Letters, 87(16) 161602, (2001).

Steven Giddings and Scott Thomas, “High energy colliders as black hole factories: the end of short-distance physics,” Physical Review D 65(5) (2002) 056010.

CERN itself considered the possibility of black hole production in the following paper. This paper predicts that black holes will dissipate by “thermal processes,” which in this context means Hawking radiation.

J.-P. Blaizot, J. Iliopoulos, J. Madsen, G.G. Ross, P. Sonderegger, and H.-J. Specht, “Study Of Potentially Dangerous Events During Heavy-Ion Collisions At The LHC: Report Of The LHC Safety Study Group” CERN, 2003.

2) The black hole does not dissipate via Hawking radiation. This failure to dissipate is predicted by some physics papers.

The following two papers question the fundamental theory behind Hawking radiation.

Adam D. Helfer, “Do black holes radiate?” Reports on Progress in Physics. Vol. 66 No. 6 (2003) pp. 943-1008.

William G. Unruh and Ralf Schützhold, “On the Universality of the Hawking Effect,” Physics Review D 71(2005) 024028.

3) The black hole then begins to slowly accrete particles. This accretion increases exponentially, with the increase in mass and size of the black hole. In a few years (or a few billion, depending on the theory) it swallows Earth.

You don’t want me to mention Roessler, but he has the only published work that I know of on this topic. Wouldn’t you be more comfortable if something this serious had been studied in more detail? I know of another Ph.D. physicist who also calculated that a collider-created black hole could eat earth in a few years, but his work has not been published. I had a posted debate with Landsberg where he made an offhand estimate that accretion would take a very long time, but that was not published in a peer-reviewed journal. Others also say that it would take a very long time. Until there is more peer reviewed work on this topic, we really don’t know what would happen, but at least some physicists calculate rapid accretion.

You also ask: “who are those theorists and how do they know ‘precisely’ what is going on at CERN? Do they or are they involved in the project? Are they as qualified as those who do?”

All of these theorists know the published design energy specifications for CERN collisions. Their predictions are based on those specifications. Unruh is a top specialist in quantum gravity. Landsberg has a top reputation. Helfer is thought to be pretty competent. I believe that all authors of papers I have cited are Ph.D. physicists.

However, you are asking the wrong question. The issue is not who is the most competent. The issue is whether any are total crackpots who we should dismiss out of hand. Any who are not total crackpots just might be correct. In the case of the safety of Earth, we do not want to dismiss a warning just because it was issued by the number three guy. In the case of the space shuttle challenger disaster, the engineer who warned of o-ring problems was not the lead engineer.

Are you familiar with the precautionary principle? The precautionary principle reverses the burden of proof in cases of scientific risk. Normally scientific publication requires good evidence that one’s theories are true. For example, the standard for publication is statistical significance, meaning loosely that the probability that the data shows the observed effect is at least 95 percent. (Some statisticians would quibble with this wording, but I have an MS in statistics, and I will defend it.) Now imagine applying this standard for proof to a risky activity. For example, the probability that the airplane will crash is only 50 percent. We haven’t proved that it will crash, so we will approve it to fly. Would you want to fly on that airplane? The precautionary principle reverses the burden of proof in cases of risk. Instead of requiring that risks be proved, the precautionary principle requires that those who propose a risky activity prove that it is safe. The precautionary principle is accepted by many risk specialists.

I bring up the precautionary principle because the spirit of your questions is to try to prove what is most likely to happen, in this case by consulting the most qualified specialists. In this case the thing that is most likely to happen is that CERN will turn out to be safe. The precautionary principle, on the other hand, tells us to worry about things that might not happen. Remember our risky airplane. It is most likely that it will not crash. It is most likely that the tiger is not hungry today. We are talking about possible destruction of Earth here. I think most rational people want that to be very unlikely to happen. If there is a serious reason to think it might happen, that is of concern, even if the serious reason comes from someone who is not the top scientist at CERN. In fact, CERN’s Chief Scientific Officer, Jos Engelen, was recently quoted in the New Yorker as instructing CERN scientists to say that the risk is zero. Should we simply salute and accept that? As a statistician I can tell you that a zero probability doesn’t make sense.