The upcoming Large Hadron Collider (LHC) at CERN could be dangerous. It could produce potentially dangerous particles such as mini black holes, strangelets, and monopoles.
A CERN study indicates no danger for earth, [Ref. 1] but its arguments are incomplete. The reasons why they are incomplete are discussed here.
This paper considers mainly micro black holes (MBHs) with low speeds. The fact that the speed of resultant MBHs would be low is unique to colliders. An important issue is the rate of accretion of matter subsequent to MBH creation.
This study explores processes that could cause accretion to be significant.
Other dangers of the LHC accelerator are also discussed.
I. Arguments for danger in LHC particle accelerator experiments
“In the 27-kilometer-long circular tunnel that held its predecessor, the LHC will be the most powerful particle accelerator in the world. It will smash fundamental particles into one another at energies like those of the first trillionth of a second after the Big Bang, when the temperature of the Universe was about ten thousand trillion degrees Centigrade.” [Ref. 5]
1. There is a high probability that micro black holes (MBHs) will be produced in the LHC. A reasonable estimation of the probability that theories with (4+d) dimensions are valid could be more than 60%. The CERN study indicates in this case a copious production of MBHs at the LHC. [Ref. 1] One MBH could be produced every second. [Ref. 4 & Ref. 5]
2. The CERN study indicates that MBHs present no danger because they will evaporate with Hawking evaporation. [Ref. 1] However, Hawking evaporation has never been tested. In several surveys, physicists have estimated a non trivial probability that Hawking evaporation will not work. [Ref. 9] My estimate of its risk of Hawking evaporation failure is 20%, or perhaps as much as 30%.
The following points assume MBH production, and they assume that Hawking evaporation will fail.
3. The cosmic ray model is not valid for the LHC. It has been said that cosmic rays, which have more energy than the LHC, show that there is no danger. This may be true for accelerators that shoot high energy particles at a zero speed target. This is similar to cosmic ray shock on the moon’s surface. In these cases the center of mass of interaction retains a high speed. This is different from the situation at the LHC, where particles with opposing speeds collide. With cosmic rays (mainly protons in cosmic rays) we need a speed of 0.9999995 c to create a micro black hole of 1 TeV and after the interaction the micro black hole center of mass will have a speed of 0.999 c. As MBHs are not very reactive with matter, calculations indicate that this is more than enough velocity to cross planets or stars without being caught and to escape into space.
4. Lower speed MBHs created in colliders could be captured by earth. Using Greg Landsberg’s calculation [Ref. 3] of one black hole with velocity less than escape velocity from earth produced every 10^5 seconds at the LHC, we have 3.160 (US notation 3,160) MBHs captured by earth in ten years. More precise calculations show that we could have a distribution of MBHs at every range of speed from 0 m/sec to 4 m/sec. The probability of very low speed MBHs is not zero. We need to evaluate if low speed MBHs present more risks.
5. The speed of a MBH captured by earth will decrease and at the end MBHs will come to rest in the center of earth. The speed will decrease because of accretion and interaction with matter.
If we consider that:
a. The CERN study’s calculus for accretion uses the “Schwarzschild radius” for the accretion cross section. [Ref. 1] In the case of low speeds, we must not use the Schwarzschild radius for the calculus of accretion. There are several reasons the capture radius extends beyond the Schwarzschild radius. For example, if the MBH speed were zero, gravitational attraction would be active at a distance greater than the Schwarzschild radius.
b. If a MBH accretes an electron, it will acquire a charge and then probably accrete a proton.
c. If a MBH accretes a quark it will then probably accrete a proton. When a quark is caught, the whole nucleon can be expected to be caught because otherwise the black hole would have acquired a charge which is not complete. (For example minus 1/3.) In a nucleus a fractional charge is unstable and is not allowed. This strongly suggests that the MBH will be required to accrete other divided charges to reach a completed integer number of charges. The same process can be expected in regard to quark color.
d. Gauge forces at short distances could also help to capture an atomic nucleus.
Our calculus indicates that a slow speed MBH can be expected to capture 8.400 (US notation 8,400) nucleons every hour, at the beginning of an exponential process.
6. In the center of earth new processes could occur: As stated above, it has been estimated that in ten years 3.160 (US notation 3,160) MBHs could be captured by earth. All MBHs will progressively lose speed because of numerous interactions. After a time (calculations have to be completed to estimate this time) all these MBHs will go toward the precise gravitational center of earth. (Kip Thorne [Ref. 7 p. 111]) After numerous interactions they will stop there at rest and then coalesce into a single MBH. To get an idea and for a first approach our calculus indicates that the mass of this MBH could be on the order of 0.02 g with a radius of 4 x 10^-17 m. At the center of earth, the pressure is 3.6 x 10^11 Pascals. [Ref. 8]. This pressure results from all the matter in Earth pushing on the electronic cloud of central atoms. The move of electrons is responsible of a pressure (called degenerescence pressure) that counterbalance the pressure of all the matter in Earth.
Around a black hole there is not an electronic cloud and there is no degenerescence pressure to counterbalance the pressure of all the Earth matter.To indicate the pressure we must use the surface If in an equation Pressure P = Force F / Surface S if we keep F= Constant and we reduce surface, we are obliged to notice that Pressure P will increase. Here F is the weight of all the matter of Earth and this do not change. As the surface of the MBH will be very small, calculus indicate on this surface an impressive increase of pressure in the range of : P = aprox 7 x 10 ^ 23 Pa .
The high pressure in this region push strongly all the matter in direction of the central point where the MBH is.
Electrons directly in contact with the Micro Black Hole will first be caught, then the nucleus will be caught.
It is sure that the atoms will be caught one after the other but the more the pressure will be important the more the caught will be quick. When a neutron star begins to collapse in a black hole (implosion), at the beginning the black hole is only a micro black hole as we see in [Ref. 7 Page 443]. At this very moment the high gravitational pressure in the center of the neutron star is there breaking the “strong force” which lays between the quarks located into the neutrons.
The MBH will grow there only because of the high pressure.
In center of Earth pressure is normally far to small for such a process, but if we create a slow speed MBH that does not evaporate and if this MBH comes at rest in the center of Earth, the pressure in the center of Earth could be sufficient for the growing of the MBH. We must remember that in the surrounding of the MBH the “strong force” is broken and this could mean that the same kind of pressure process than in neutron star could work there ( in a slow mode compared with a neutron star of course ). In the center of Earth, the high pressure, the high temperature, the increasing mass associated with electrical and gauge forces process could mean important increase of capture and a possible beginning of an exponential dangerous accretion process. Our calculus indicates as a first approximation with a MBH of 0.02 g at rest at the center of earth that the value for accretion of matter could be in the range of 1 g/sec to 5 g/sec.
7. Conclusion about MBHs : We estimate that for LHC the risk in the range of 7% to 10%.
II. Other Risk Factors
The CERN study indicates that strangelets and monopoles could be produced and present no danger for earth. [Ref. 1]
We will present arguments of possible danger.
Strangelets are only dangerous for earth if they are not moving rapidly through matter. If only one strangelet is at zero speed there would be danger. We have seen for MBHs that the cosmic ray model is very different from the LHCwhere particles with opposing speeds collide. We have seen that, given the impact of opposite speed particles, the distribution of speeds of resultant particles indicates the probability of very low speeds (0 m/sec < speed < 4 m/sec) and this could mean dangerous strangelets. We estimate a minimal risk for strangelets on the order of 2%. We might estimate as high as 10 % if we want to be wise because the danger is primary!
Monopoles could be produced in the LHC. [Ref. 1] .CERN’s calculations indicate that one monopole produced in LHC could destroy 1.018 (US notation 1,018) nucleons but it will quickly traverse the earth and escape into space. However, we know that photons produced in the center of the sun need thousands of years to traverse the sun and escape into space because of the numerous interactions. If the speed given to the monopole after interaction is a speed in a random direction, we can imagine that the monopoles produced in the LHC could stay a very long time in earth and be dangerous. 3. Estimate of danger due to our ignorance of ultimate physical laws: We have not exhausted processes that might cause danger. There are other particles, black energy, black mass, quintessence, vacuum energy, and many non definitive theories. We estimate this danger ranging from a minimal 2% risk to 5%.
The CERN study [Ref. 1] is a remake of a similar study for the earlier Relativistic Heavy Ion Collider at Brookhaven (RHIC) [Ref. 6] adapted to the LHC.
It is important to notice that: The study for the RHIC had concluded that no black holes will be created. For the LHC the conclusion is very different: “Black holes could be created!” !
The main danger could be now just behind our door with the possible death in blood of 6.500.000.000 (US notation 6,500,000,000) people and complete destruction of our beautiful planet. Such a danger shows the need of a far larger study before any experiment ! The CERN study presents risk as a choice between a 100% risk or a 0% risk. This is not a good evaluation of a risk percentage!
If we add all the risks for the LHC we could estimate an overall risk between 11% and 25%!.
We are far from the Adrian Kent’s admonition that global risks that should not exceed 0.000001% a year to have a chance to be acceptable. [Ref. 3] .Even testing the LHC could be dangerous. Even an increase in the luminosity of the RHIC could be dangerous! It would be wise to consider that the more powerful the accelerator will be, the more unpredicted and dangerous the events that may occur! We cannot build accelerators always more powerful with interactions different from natural interactions, without risk. This is not a scientific problem.
This is a wisdom problem!
Our desire of knowledge is important but our desire of wisdom is more important and must take precedence. The precautionary principle indicates not to experiment. The politicians must understand this evidence and stop these experiments before it is too late!
Fausto Intilla –
1.. Study of potentially dangerous events during heavy-ion collisions at the LHC: Report of the LHC Safety Study Group. CERN 2003-001. February 28, 2003.
2.. E-mail exchange between Greg Landsberg and James Blodgett, March 2003, http://www.risk-evaluation-forum.org. (No longer posted. Request a copy. Risk Evaluation Forum, BOX 2371, Albany, NY 12220 0371 USA.)
3.. A critical look at risk assessment for global catastrophes, Adrian Kent, CERN-TH 2000-029 DAMTP-2000-105. Revised April 2003. hep-ph/0009204. Available at: http://arxiv.org/PS_cache/hep-ph/pdf/0009/0009204v6.pdf
4.. High energy colliders as black hole factories: the end of short distance physics, Steven B. Giddings, Scott Thomas. Phys Rev D65 (2002) 056010.
5.. CERN to spew black holes, Nature October 2, 2001.
6.. Review of speculative disaster scenarios at RHIC September 28, 1999 W.Busza, R.L. Jaffe, J.Sandweiss and F.Wilczek.
7.. Trous noirs et distorsions du temps, Kip S. Thorne, Flammarion 1997. ISBN 2-08-0811463-X. Original title: Black holes and times warps. 1994 Norton. New York.
8.. Centre de la Terre, Science & Vie N 1042. Gallate 2004.
9.. Results of several Delphi groups and physicist questionnaires, James Blodgett, Risk Evaluation Forum, forthcoming.