Thanks & regards.

High energy cosmic ray constituents — I haven’t followed up the question of what the range of view actually is in astrophysics about what the possible proportions of proton to iron cosmic rays would be, but within the LSAG report — and with the references that the report relies on — seems to given as between 10% and 90% for protons cosmic rays at these LHC comparable collision energies (with other nuclei being supposedly much less likely).

Cosmic ray to earth collisions — ie rate of cosmic rays hitting particles in the atmosphere of the earth. I don’t see a particular reason to doubt the estimate of Mangano and Giddings in their paper http://arxiv.org/abs/0806.3381 given at end of page 28 (including formulae) : 1/A x 10^22 (which is 1 × 10^22 for proton or 1.8x 10^20 for iron nuclei cosmic rays) during the time of the earth’s existence. (Actually that value doesn’t include the very highest energy cosmic rays whose flux is difficult to estimate).

That’s not to say that these sorts of statistics provide a reliable safety assurance.

LSAG and two –way collisions — they didn’t deal with this as they rely on the following couple of questionable arguments dependent on only nuclei cosmic ray to ‘stationary’ nuclei collisions — which you may be aware of. One of these tenuous assumption relates to strangelets — if there is a strangelet danger there would be enough undestructible, slow moving strangelet by products of collisions to have anyway led to higher than observed rates of supernovae. In the black hole case they effectively rely on the conclusion of Mangano and Giddings paper that the survival of 8 identified white dwarfs couldn’t have occurred if there was a risk from micro black holes. For the first argument no evidence, even of a very indirect and thereby unsatisfactory sort — from RHIC data — is actually presented to support it even though this is claimed. The second avoids any statistical analysis comparison in relation to any unobserved massive black holes that could have emerged subsequently from white dwarfs of the relevant vulnerable type if they were afflicted by micro black holes. But there are better arguments against this second assurance. One would be that high energy cosmic rays may actually emerge from only certain specific locations- as has been suggested in the relevant literature — and that furthermore their angular range of emission from these sources could be limited — something accepted in an email communication to me from an astrophysicist. Also various neglected factors in the calculations of accretion rates are involved in Mangano and Giddings paper along with their neglect of the slow decaying black hole scenario.

The maximum speed for a strangelet — this is estimated by Dar et al.s paper on RHIC/ LHC safety (1999) to be 1/10 of light speed. This seems to me could be significantly too slow as it is based on the speed for disruption of mult-nucleon nuclei — which themselves are not singly bound while strangelets are. But it can nevertheless be used within either pro-risk or pro-safety assessments.

Threshold energy for strangelet production — I think it is more likely the collision energy needs to be above a certain threshold than below (but possibly both). There is some indication for a minimum threshold at just above RHIC’s collision energy from cosmic ray detector results that are discussed in papers by team members of CERN’s own not so publicised strangelet search project at LHC — CASTOR.

Strangelets as dark matter. Don’t think I’ve come across that — doubtful I think.

Two way collisions and strangelets. Yes, it seems to make a lot more sense to talk about the starting point for stars being simply interstellar gas clouds not initially empty space (which would alledgedly be subsequently much contracted after supernovae shock waves) where the problems I mentioned in my last posts emerge.

Two-way collisions in the vicinity of compact stars/ stars/ planets or their satellites without atmospheres would be a good comparison to make certainly better than what LSAG report relies on. Would be better even there though if we have direct knowledge of the constituents of these high energy cosmic rays for the comparison.

Metastable particles — Yes possibility applies to both micro black holes and to collision induced strangelets and I think makes reliability of safety arguments more difficult again.

Higher energies and risk. The two issues for the longer term I think are the prospect of a minimum energy for black hole creation being from above the 8TeV to be achieved this year and also the total number of collisions [awkwardly given conventionally in terms of ‘anti femto barns’} that would be achieved by the end of this year. The value by then would still be very much lower than would be achieved some time after the highest/ design energy collisions have started in a few years — magnifying both the chances of creating dangerous stranglelets or micro black holes and of the number of any of them which itself increases the rate by which any catastrophe would occur.

Eric

A friend told me that the 4th link in my long answer to Peter Conant (Niccolò Tottoli on February 14, 2012 7:43 pm) does not work.
Here is it:
http://www.achtphasen.net/index.php/plasmaether/2011/09/02/h…uido#c5903
My intention was to show that different people came to a similar result which leads to the conclusion that the cosmic ray argument (CERN´s No.1 repeated safety argument) is flawed.

Thank you for your interest.

Better: “I often say a bit provocative that there was never a frontal collision, with two equally fast protons or lead ions with LHC design energy or more 1 meter…”

Better: “If the probability estimate (that there would be absolutely no risk) given by an argument (the cosmic ray argument) is enlarged by the chance that the argument itself is flawed, then the estimate is suspect.“
—–

Dear Eric

Now to your comment.
Thank you for your argument: “the mentioned lack of direct evidence for cosmic ray particles at energies comparable to LHC is well worth taking into account”.
Then you wrote: “even that calculation would have to assume at least some proportion of such ordinary nuclei cosmic rays.” The question is: how many? For example I have read that only cosmic rays with 2TeV have directly been measured. Please see the very interesting comment (regarding other points too) of LHC Kritik on February 16, 2012 1:25 pm on lifeboat in the following blog theme (11th paragraph):
http://lifeboat.com/blog/2012/02/lhc-critique-press-release-…ent-102017

I just found it remarkably that all people in the various links that I have shown in my answer to Mr. Conant have come to a similar conclusion — that natural head-on collisions with LHC-design energy or more, with two (with respect to neighboring celestial bodies) equally fast particles are very seldom and do usually not happen near celestial bodies, because of various reasons (for example the shadow of the body and so on).

You say that you would doubt about the calculation result relating to number of cosmic ray collisions on Earth at “relativ-kritisch” from LHC-design energy but I have shown other links too. One point is that it seems they have not considered the different distribution of matter in the young universe. Perhaps you can tell us an other value? Formulas are often too difficult for me but I collect them, read the words and compare the results. If you have additional links or calculations then it would be great to have them. Physicists should double check them.

The difference it makes. One thing are frontal collisions of pairs of protons or lead ions in the (nearly) empty space of our solar system or the Milky Way. But it is an other thing if both collision partner have an equal velocity with respect to the celestial body near to the collision. To avoid confusion one has to tell these parameters in all safety arguments regarding cosmic rays. Obviously they have often been not so precise in the LSAG-report. Why?

Strangelets could be produced in the “empty” space of the Milky Way. But it depends on the speed. If a strangelet is smashed very fast into matter, the strangelet could be destroyed. How slow must a strangelet be, to survive if it strikes matter?

Strangelets are hypothetical particles and nobody knows the collision energy at which they might be produced. The higher the required collision energy the rarer the natural strangelets. Perhaps slow natural strangelets have never (or very seldom) been produced enough near celestial bodies to pose a risk and have had time to decay to their ground state, which is predicted by most models to be positively charged, so they are electrostatically repelled by nuclei, and would rarely merge with them. But high-energy collisions could produce negatively charged strangelet states which would live long enough to interact with the nuclei of ordinary matter, because they would be produced very near the surface of Earth (respectively at the LHC).
http://en.wikipedia.org/wiki/Strangelet#Dangers

Ok, you have told about the gas clouds in the young Milky Way. I can not find the value of 2500 strangelets, which would have been produced by cosmic rays (heavy nuclei) so please can you tell me the time-span? But then, what about the decay to their ground state? Could strangelets or micro black holes be part of dark matter? Scientists tell that there is much more dark matter in the universe than ordinary matter.
Why is this so? Should we not be more careful?

The LSAG-report makes many assumptions, estimations and often tells not the complete truth (I could show you various examples), therefore it is great if people like you do research and try to find “holes” in such safety papers, to show risks. We know both that the strangelet issue is a very contradictory one. I am sure that you could show a link or tell some facts here with respect to it…

Micro black holes are hypothetical particles too and we do not know at which collision energy they will be produced. They say it depends on the fundamental Planck scale. The higher the required collision energy for MBH-production, the rarer the MBHs.
Calculations and variable computer models should be made, to see whether there could be a risk in certain circumstances and within certain parameters.
Your point regarding the creation of the universe is a very good one and all parameters of such aspects should be included into these proposed computer models too, to evaluate “LHC-like” cosmic ray collisions or the natural production of all hypothetical dangerous particles over the required period of time.
For the moment very long periods (as the evolution of the Milky Way) may only tell something about infinitely stable hypothetical particles like micro black holes.
But one more time: It is very important to consider metastable dangerous particles too. To be absolutely safe, all possible reactions and islands of stability of all possible particles and fields have to be theoretically considered, also in terms of their velocity, growth rate, penetration depth and similar things, when they traverse space-time and different densities of matter.

I often say a bit provocative that there was never a frontal collision, with two equally fast protons or lead ions with LHC design energy 1 meter or less above the surface of dense celestial bodies in our entire solar system and probably not too in the Milky Way since the existence of Earth. Nobody has shown me the contrary yet. Can you?

We can be obviously glad that the planet has not yet be blown up by men but how can we be sure that nothing dangerous will happen at higher energies?

I am sure that a continuous interdisciplinary and independent safety assessment between CERN and the scientists referring to risks would help much more to be safe than discussions in blogs between laymen like me and critical minds like you.

Thank you for the interesting discussion and for your great research.

Sincerely yours,

Niccolò
——-

Worst mistake to make is to have to correct a correction back to original! Unfortunately my last comment requires that. The volume of strangelets produced by this mechanism would be for within the volume of our milky way — though from a vastly greater initial volume of contracted interstellar medium. The vastness of that initial volume per solar mass star is given in the Dar et al. paper in section 3 or 4 (1x10^-57cm^3).

Eric