This has been in the works quite a while, but is only now reaching the web. In October, I did an interview with Carolyn Weaver of Voice of America TV about RHIC, it's science, and the controversies surrounding the various "doomsday" scenarios proposed in the 80's and 90's. It's now posted on the VOA website.What I hadn't realized when I agreed to give this interview was that Weaver had already spoken to Richard Posner, the eminent federal judge. Posner wrote a book in 2004, "Catastrophe: Risk and Response", which discusses the risks of RHIC, among other disasters, and how we are currently not dealing with various eventualities. And here in the final product (shown to the right), I find myself superimposed on Posner, if only for a brief instant. How many of my lawyer friends can say that?
I've discussed Posner and other critics various times in my previous blog, and I maintain that I find their arguments still less than compelling in their particulars. But I never imagined I'd get a chance to say so in public. I still believe that while we should take risks seriously, and in general scientists should be held accountable for the risks they take, and discuss them openly. However, we must constantly be updating the level of risk based on incoming information. Posner (and Rees, for that matter) are basing everything on several papers written in 1999 and before, well before the RHIC data came in. Since that time, we have found that the matter we create at RHIC essentially blows apart as soon as it is made. And more importantly, this matter is not baryon rich, as it was at the AGS. This suggests to me that we're even less likely to make stable strange matter than ever before. That said, I should not be construed to be a real expert on this subject. But that said, no expert I know has suggested that the risk level has increased. There have even been searches for strangelets at RHIC (in the baryon-rich forward region) which have (as always) come up empty!
So until my colleagues A) actually isolate even a hint of a strangelet signal, and B) start to believe (based on experimental data) that RHIC is really a better enviroment for their production than previous facilities (which have established stringent upper limits), I think it's premature to start any serious discussions of the risk of RHIC to humanity as a whole. But I'm sure someone out there already disagrees with me.
5 comments:
Peter:
I do not think you are actually taking risks seriously. It is true that the risks, evaluated based on our current knowledge, is small, extremely small. No one dispute that. However, the risk, however small, is not precisely zero, and consequence if something goes wrong is just too much a catastropy to be ignored. If for example a black hole is created, and that unfortunately Stephen Hawking was wrong and there is no blackhole evaporation, then too back the whole earth will be swallowed, together with the whole of humanity.
In such case the catastropy is infinity, and the chance of that happening, however small, let say only one out of a billion, or one out of a bizilion, when multiplied by infinity, is still an infinite.
Since any small number multiplied by infinity is still infitity, unless the number is exactly zero. It is now up to you to show me, on mathematically rigious terms, that the risks is not just negligible, but must be precisely ZERO. So you have to show me:
1.Our current knowledge is absolutely reliable and absolutely complete. And predictions made are absolutely correct, with no unexpected surprises possible.
2.We know everything already and there is no possibility that any part of our knowledge needs any correction in the future.
I don't know how you can tell me that, if you can, then there is no need for any high energy physics research. If there is need for research, that means our knowledge is incomplete and our assessment of the risk could be wrong and the risk is none-zero. And so when the consequence could be as serious as the complete annihilation of humanity, even the smallest possibility of risk is un-acceptable. Once again, infinity times any small number is still infinity.
Quantoken
BNL seems to post on its web site only the original "Review of Speculative Disaster Scenarios" at RHIC by Jaffe et al., not their later, revised version issued in response to criticism.
Links to that amended version, as well as to mathematician Adrian Kent's paper raising some of the risk-analysis and policy issues regarding RHIC are on the VOA web site next to my story. --Carolyn Weaver
Peter:
As a lawyer since 1977, and a nuclear physicist since 1973, and a biologist since 1970, I brought a unique perspective to an analysis of the RHIC when I filed suit in Federal court seeking a safety analysis prior to its start-up. The forthcoming LHC at CERN in Switzerland raises the same issues, but even more so.
It's been announced that no strangelets have been found in searches for them at RHIC. The predecessor accelerator (now the RHIC injector) also sought strangelets, but did not find them.
What has NOT been announced is that the search was for positive or negative strangelets. Neutral strangelets cannot be detected by their detectors, so if neutral strangelets are being produced, we won't know about it (until its too late, if they prove to be a 'toxic waste' as predicted). It is also quite possible that the energy is still too low (we need a LHC to create strangelets?), or more plausibly, strangelets are purely a figment of the imagination of theoreticians, and are impossible to create under any conditions.
The theoretical prediction for strangelets is that they will undergo a 'runaway fusion' process (because they are predicted to be a more stable state than normal nuclear matter, once created - this is well detailed in the literature), but that the 'runaway fusion' process will be at an extremely low but exponentially increasing rate (unlike fission, which increases exponentially rapidly, because on average 2.3 neutrons are released for each incoming neutron). It might take literally many millions to billions of years for a single strangelet to fuse with enough atoms over time to grow large and be able to produce an appreciable non-stoppable fusion energy output; yet with the production of thousands of them, the large-scale non-stoppable fusion energy output could be reduced to occurring only a few thousand years into the future, not millions to billions.
It is that scenario which has not been disproven, and which many theorists with excellent credentials show to be a possible, indeed plausible, outcome. We just don't know as of yet.
The cosmic ray argument is predicated upon the assumption that production of a single strangelet, should it prove 'dangerous', would result in near-instantaneous destruction of the moon. The argument fails when it fails to address the slow accumulation of lots of strangelets over time, produced at a rate far greater than produced in nature.
Walter
Another aspect of strangelet production not mentioned in my previous post here is that strangelets produced on the moon from energetic high-Z cosmic rays impacting on stray Uranium atoms lying on the moon's surface (which most closely mimics the RHIC and LHC collisions of Gold on Gold atoms), if neutral, would zip right on through the moon at nearly the speed of light. Even the occasional rare collision would not stop their forward motion, and they would simply exit the moon in a tiny fraction of a second after their creation.
Conversely, any neutral strangelets created at the RHIC or LHC would be relatively stationary compared to Earth's reference frame, and most would simply fall downward under gravity, though possibly after acquiring/incorporating a few Hydrogen or Helium nuclei, which are in great abundance at both colliders, but which low-Z atoms are in much greater scarcity at the moon.
That scenario is a qualitative difference between relatively rare potential strangelet production on the moon by nature, and strangelet production by colliders on earth.
The Large Hadron Collider [LHC] at CERN might create numerous different particles that heretofore have only been theorized. Numerous peer-reviewed science articles have been published on each of these, and if you google on the term "LHC" and then the particular particle, you will find hundreds of such articles, including:
1) Higgs boson
2) Magnetic Monopole
3) Strangelet
4) Miniature Black Hole [aka nano black hole]
In 1987 I first theorized that colliders might create miniature black holes, and expressed those concerns to a few individuals. However, Hawking's formula showed that such a miniature black hole, with a mass of under 10,000,000 a.m.u., would "evaporate" in about 1 E-23 seconds, and thus would not move from its point of creation to the walls of the vacuum chamber [taking about 1 E-11 seconds travelling at 0.9999c] in time to cannibalize matter and grow larger.
In 1999, I was uncertain whether Hawking radiation would work as he proposed. If not, and if a mini black hole were created, it could potentially be disastrous. I wrote a Letter to the Editor to Scientific American [July, 1999] about that issue, and they had Frank Wilczek, who later received a Nobel Prize for his work on quarks, write a response. In the response, Frank wrote that it was not a credible scenario to believe that minature black holes could be created.
Well, since then, numerous theorists have asserted to the contrary. Google on "LHC Black Hole" for a plethora of articles on how the LHC might create miniature black holes, which those theorists believe will be harmless because of their faith in Hawking's theory of evaporation via quantum tunneling.
The idea that rare ultra-high-energy cosmic rays striking the moon [or other astronomical body] create natural miniature black holes -- and therefore it is safe to do so in the laboratory -- ignores one very fundamental difference.
In nature, if they are created, they are travelling at about 0.9999c relative to the planet that was struck, and would for example zip through the moon in about 0.1 seconds, very neutrino-like because of their ultra-tiny Schwartzschild radius, and high speed. They would likely not interact at all, or if they did, glom on to perhaps a quark or two, barely decreasing their transit momentum.
At the LHC, however, any such novel particle created would be relatively 'at rest', and be captured by Earth's gravitational field, and would repeatedly orbit through Earth, if stable and not prone to decay. If such miniature black holes don't rapidly evaporate and are produced in copious abundance [1/second by some theories], there is a much greater probability that they will interact and grow larger, compared to what occurs in nature.
There are a host of other problems with the "cosmic ray argument" posited by those who believe it is safe to create miniature black holes. This continuous oversight of obvious flaws in reasoning certaily should give one pause to consider what other oversights might be present in the theories they seek to test.
I am not without some experience in science.
In 1975 I discovered the tracks of a novel particle on a balloon-borne cosmic ray detector. "Evidence for Detection of a Moving Magnetic Monopole", Price et al., Physical Review Letters, August 25, 1975, Volume 35, Number 8. A magnetic monopole was first theorized in 1931 by Paul A.M. Dirac, Proceedings of the Royal Society (London), Series A 133, 60 (1931), and again in Physics Review 74, 817 (1948). While some pundits claimed that the tracks represented a doubly-fragmenting normal nucleus, the data was so far removed from that possibility that it would have been only a one-in-one-billion chance, compared to a novel particle of unknown type. The data fit perfectly with a Dirac monopole.
While I would very much love to see whether we can create a magnetic monopole in a collider, ethically I cannot currently support such because of the risks involved.
For more information, go to: www.LHCdefense.org
Regards,
Walter L. Wagner (Dr.)
Post a Comment