Archive for the ‘Risk Calculations’ Category

Could the Real Risk to the Planet be Closer to 100%?

Wednesday, June 4th, 2008

The following exchange took place on the Talk page of the Wikipedia article for the Large Hadron Collider primarily between myself and Bill Wwheaton who has been representing CERNs interests concerning safety content of this article.

Wikipedia Large Hadron Collider Article, Talk Page

Rees & Close

Risk Calculations and Assumptions reasonable quality, short discussion of risks and calculations at Martin Meenagh blog and some related calculations at James Blodgett on Risks Including this assessment:

If the following reasonable and plausible assumptions prove to be correct, then the uncomfortable truth may be that the probability of destruction of Earth could be closer to 100%, far from the often quoted 1 in 50 million, though only mother nature currently knows for certain due to our limited understanding of the physics involved.
A. LHC Creates black holes as CERN Predicted (1 per second) 1.
B. Micro Black holes do not evaporate as LSAG accepts is plausible. 2
C. One or more micro black holes are captured by Earth’s gravity as LSAG accepts as plausible. 3
D. Micro Black holes grow exponentially as Dr. Otto E. Rossler‘s paper predicts and calculates. 4

Jtankers (talk) 15:45, 3 June 2008 (UTC)

Looking at the references, I think they do not support the attached statements, and in fact the entire post is just a copy of one to an outside blog. I think we are in a rut here, and have posted a suggestion for getting out in a new section below. Bill Wwheaton (talk) 10:27, 4 June 2008 (UTC)
I disagree, all of the statements are fully supported and supportable. Do you dispute the factuality of any of the statements? —Jtankers (talk) 15:25, 4 June 2008 (UTC)
Yes, I dispute A, that CERN predicted BH production at 1 BH/s, certainly not in the reference 1; B, I do not agree that LSAG (LHC Safety Assessment Group) accepts the invalidity of Hawking’s BH evaporation as plausible; or that the reference given 2, to Helfer’s paper, supports the assertion that they do; C, I do not see that your [8] ref 3, supports your claim that “LSAG accepts…”; and D, while Ressler predicts (& I agree) that a micro-BH inside the Earth would probably grow exponentially after reaching a certain size, this only leads to a meaningful statement about risk (compared to other inevitable planetary risks) when the characteristic timescale for the exponential growth is specified as well. The natural growth time with reasonable accretion efficiency seems to be millions of years, and it appears to me that at least twenty such periods should be required.
Then again, your apparent quotation re “…reasonable and plausible assumptions …” , which appears to be an outside reference, is actually just a verbatim copy of the above post, by you, as posted to a blog. It is clearly not a reliable source according to Wiki standards, and I cannot personally accept it as reasonable or plausible. Finally, your …“could be close to 100%”… statement, if supposed to be supported by multiplying your four likelihoods together—each cherry-picked from the extreme fringes of uncertainty in my opinion—is really not a probability at all (or else if it is, then I can respond that “the probability of destruction of the Earth is 99.9% in any case”, with perfect assurance. FYI, when I multiply my own “worst reasonable case” estimates of the above four probabilities together I get 1/300,000,000, with the additional caveat that if BHs are produced at LHC (only for special ranges of string theory compactification, etc) then they should interact strongly with the Earth, and the cosmic-ray argument, applied to neutron stars, would take hold and reduce the odds by a further factor of maybe 1000. And as one final point: I think it is not reasonable to assume that all the more than 2000 knowledgeable scientists working on LHC are so demented or in denial as to be incapable of assessing the danger of mass murder & suicide for themselves and their families. The essence of sanity is to be able to distinguish between what is possible and what is probable , after all. (This is supposed to be easy, but in the modern world, I fear it is not.)
So forgive me, James; I believe you are sincerely worried, and on a mission to save the Earth, and I have to honor that even though I think your arguments are not convincing. I will continue to defend this front until I see more clearly, either here or in another dedicated article. Best, Bill Wwheaton (talk) 00:29, 5 June 2008 (UTC)
Hello, Bill,

You state that you have some questions about or dispute points A, B and C. The following citations and relevant quotes support the assertions above, plus a brief summary of Dr. Otto E. Rossler’s theory of fast accretion that was posted to LHCFacts.org

A. LHC Creates black holes as CERN Predicted (1 per second)
STUDY OF POTENTIALLY DANGEROUS EVENTS DURING HEAVY-ION COLLISIONS AT THE LHC
“… we see that the (4 + d) black hole will be produced if M is not much larger than 1 TeV.”
The case for mini black holes, CERN Courier
“… the Large Hadron Collider (LHC) could allow it to become a black-hole factory with a production rate as high as about one per second”
B. Micro Black holes do not evaporate as LSAG accepts is plausible.
LHC: what if … ? Michelangelo Mangano CERN, TH-PH
“At the LHC, some [MBH] … could start growing”
LHCSafetyAssessment.Group@cern.ch Sun 3/16/08 6:06 AM
“… we are not working under teh assumption that BHs decay. …We are in fact working under the assumption that they are stable”
Dr. Adam D. Helfer Do black holes radiate?
“this prediction rests on two dubious assumptions…”
“no compelling theoretical case for or against radiation by black holes”
Dr. William G. Unruh and Prof. Ralf Schützhold On the Universality of the Hawking Effect
“Therefore, whether real black holes emit Hawking radiation or not remains an open question”
Prof. V.A. Belinski On the existence of quantum evaporation of a black hole
“…the effect [Hawking Radiation] does not exist.”
James Blodgett (Masters Degree in Statistics) 2004 Delphi Study on LHC Risks
“I asked [15] physicists… estimates that Hawking radiation would fail ranged from 0% to 50%…” [average 9.9% doubt].
C. One or more micro black holes are captured by Earth’s gravity as LSAG accepts as plausible.
LHC: what if … ? Michelangelo Mangano CERN, TH-PH
“At the LHC, some of them [MBH] will have v<10 km/s, will be gravitationally trapped”
LHCSafetyAssessment.Group@cern.ch Sun 3/16/08 6:06 AM
“…particles that in head-on collisions … find themselves at rest.” [percentage of at rest results from head-on symmetric collisions unknown]
D. Micro Black holes grow exponentially as Dr. Otto E. Rossler’s paper predicts and calculates.
Bill Wwheaton: “while Ressler predicts (& I agree) that a micro-BH inside the Earth would probably grow exponentially after reaching a certain size”
fyi: Professor Dr. Otto E. Rossler’s theory is that when a MBH accretes a charged particle, say electron, this will not go straight into the MBH, but will circulate around the MBH for a while, and by doing this, a magnetic field will be created which will attract positive and negative charged particles, each at the opposite poles of the MBH, thus accelerating the accretion rate. He estimates potentially as few as 50 months from creation to full Earth accretion

Jtankers (talk) 04:07, 5 June 2008 (UTC)

Do you have any references that don’t need to be misrepresented to back up the views expressed on your blog? I got through the first few refs you’ve provided, before giving up. You do realise that saying “Even if X were true, Y would still be false”, does not imply that the writers feel X is is any way true, right? — Mark Chovain 05:06, 5 June 2008 (UTC)
The assertion is merely that the concept is considered plausible and that it is not reasonable to exclude the possibility. In the case of Hawking Radiation the implication is that the net consensus of the cited authors is that the probability can probably be best estimated at 50% at most. But all that is asserted is only that the concept is plausible and not reasonable to exclude the possibility. —Jtankers (talk) 05:24, 5 June 2008 (UTC)
Then at best, this whole thing is original research, because you still haven’t provided a reference showing that there are valid safety concerns. Your refs do not say that it is plausible. Some say that micro black holes likely exist (at higher energies), while others say that even if they did exist at low energies, the LHC would still be safe. That is nothing like saying it is plausible that micro black holes will be created at a rate of 1 per second: an assumption your synthesis requires. — Mark Chovain 05:59, 5 June 2008 (UTC)
The prediction of possible creation of micro black holes at a rate of 1 per second was posted on CERN’s safety web site earlier in 2008. This prediction was also published in the CERN Courier and by other news sources: The case for mini black holes, CERN Courier Quote: “… the Large Hadron Collider (LHC) could allow it to become a black-hole factory with a production rate as high as about one per second” I believe this indicates that the assertion is considered plausible by CERN. —Jtankers (talk) 12:09, 5 June 2008 (UTC)

James Blodgett on Risks

Saturday, May 24th, 2008

James Blodgett has a masters degree is statisitcs and leads the Mensa Special Interest Group Global Risk Reduction
(Orginally posted at LHC Concerns)

Why are physicists building a collider if it is dangerous? Why are they not worried? I have talked to a bunch of physicists. I will tell you my model.

At first, physicists had good reason to think that there was no problem. When Walter Wagner suggested in 1999 that black holes might be created, fairly simple math (even Wagner’s own math) showed that the energy required would be beyond the reach of any collider. The collider of interest at the time was the Relativistic Heavy Ion Collider at Brookhaven, which started up in 2000. Brookhaven produced a safety paper that listed several safety factors. To this day, physicists still cite that paper to show that there is no problem.

The problem was, subsequent physics papers eroded several of the safety factors. String theorists developed a new theory that showed how colliders could create black holes. The theory behind Hawking radiation, supposed to dissipate black holes, was found to have theoretical problems. And so forth. It is somewhat like a frog in water that is slowly heated. The frog will not notice the heat.

Part of the problem is that physicists are not risk analysts. They feel, correctly, that the theories that permit trouble are a small subset of all theories, so that trouble is not likely. As one physicist said to me “You do not understand probability. A probability of 0.001 means it is not going to happen.” Well, I have a master’s degree in statistics. I do understand probability. What the physicist did not understand is that 0.001 times the value of Earth gives a tremendous negative expected value. We should NOT be taking chances like that. A shuttle astronaut faces similar personal risks at every launch. If physicists where shuttle astronauts, we would applaud their confidence in their craft and their willingness to back up their confidence by risking their lives. However, a shuttle astronaut is a volunteer. A commercial airplane with a 0.001 risk would not be allowed to fly. A commercial airplane carries many passengers who did not volunteer for a risky mission. The Earth has 6.5 billion passengers, so we should hope for a risk to Earth that is less than that of a commercial airplane.

I once interviewed a physicist who had written an article for a popular publication telling us not to worry. His reasons were not clear from the article, so I asked him over lunch. It was a stimulating conversation, he seemed to be a nice guy, and he paid for lunch. His reason turned out to be that he did not believe in any kind of black hole. As he said, “When an equation goes to infinity, that is a sign that there is something wrong with the equation.” He has a point, and he might just be right. But that is not what most physicists believe. I applaud him for his theoretical creativity. I understand why he might not be personally concerned. But he doesn’t quite realize that he is betting the Earth, and telling others it is okay to bet the Earth, based on a theory that many would question.

Scientists are used to testing theories carefully. In order to publish, data need to be statistically significant, and they need to pass peer review. They tend to think like this about risk too, wanting it to be proven before they will believe it. (Consider, “The risk is only 50%, that is not proven, so we will launch.”) To address this, risk specialists have developed what they call the precautionary principle. The precautionary principle reverses the burden of proof in areas of scientific risk. Precaution does not need to prove risks to a high degree of confidence. Rather, the burden of proof is on those who propose risky experiments, to show that they are safe. The precautionary principle has been touted by many risk specialists, and has been formally accepted by the European Union, the home of CERN. Unfortunately, many scientists are not used to this type of thinking, are not aware of the precautionary principle, or if aware do not like it. Even those who accept it are sometimes reluctant to apply it. Even though the precautionary principle has been formally adopted by the European Union, EU functionaries are currently passing the buck as to who is responsible for its implementation.

The Large Hadron Collider at CERN is Europe’s moon shot. They have spent billions. It will bring them back to the preeminence in physics they enjoyed in 1910, when Einstein and Bohr and Heisenberg were all Europeans. Also, a sizable portion of the world’s physicists are working on the LHC, or on theories that will be impacted by the LHC. They are reluctant to hear that it might have a problem. If that problem is a low probability risk, that is a risk they are willing to take, or rather willing to ignore.

I should add that estimates of components of collider risk are quite subjective and quite variable. In 2004, I tried a series of Delphi questionnaires in which I asked physicists their estimates of several components of collider risk. As an example of the variability, estimates that Hawking radiation would fail ranged from 0% to 50%. The data are as follows: 0, 0, 1E-10, 0.001, 0.01, 0.01, 0.01, 0.02, 0.02, 0.07, 0.1, 0.1, 0.3, 0.35, 0.5. This was at the time that CERN was relying on Hawking radiation, before we were aware of the papers questioning its theoretical background. I guess that estimates would be higher now. (Note that even then, when Hawking radiation was relied upon by CERN, most physicists estimated a non- zero probability that it would fail.) Also, ten of these physicists were aware of my interest in the collider issue from the Delphi instructions. A few may have been shading their estimates to game the results. CERN’s Chief Scientific Officer, Jos Engelen, was quoted in the New Yorker as instructing CERN scientists to say that the risk (the overall risk of the LHC) is zero.

The model of risk in the Delphi questionnaires was [ Total risk ] = [ Risk that black holes would be created ] x [ Risk that Hawking radiation would fail ] x [ Risk that accretion would be rapid ] x [ Any other risk factor they propose ]. (These probabilities were stated as successively conditional, given that the earlier ones were true.) Ten of the physicists received these questionnaires, the others received a preliminary questionnaire. The fact that none proposed a fourth factor at least suggests that this model is plausible. I would consider the collider/cosmic ray analogy as a separate consideration that would limit the risk calculated by this model, but that should not be calculated into it.