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/v3-uk/news/2006988/physicists-raise-lhc-safety-doubts
29 Jan 2009, Iain Thomson , V3
New research by three physicists has raised concerns over the safety of the Large Hadron Collider (LHC), which is due to restart this summer.
Concerns had already been raised that the activities within the 27km particle accelerator could create black holes, which could in turn destroy the planet.
A lawsuit was even filed to prevent the LHC from operation which sparked ribaldry from internet users.
CERN, which operates the LHC, commissioned an extensive study which concluded that, if black holes were formed by the LHC, they would last for only milliseconds before extinguishing themselves.
However, a new study by Roberto Casadio of the University of Bologna, and Sergio Fabi and Benjamin Harms of the University of Alabama, has concluded that the black holes could survive for more than a second.
"While the growth of black holes to catastrophic size does not seem possible, it remains true that the expected decay times are much longer than is typically predicted by other models," the physicists state in a brief paper posted at the scientific discussion website ArXiv.org.
The danger would occur if the black holes stayed in existence long enough to absorb material and become self-sustaining, but the physicists say it is more likely that they would either collapse or stabilise at a very small level and drift out into space.
Do you agree?
They Have No Right To Do This
First they said it couldn't happen.
Then they say the black holes will be there for much longer but, c'mon, they're pretty sure it can't happen.
It's time for all the people who worship at the feet of Global Warming Doomsday to deflect themselves for a short time to the comparatively simple task of seeing to it that this collider never operates.
Al Gore - Mr. Nobel Prize! - could you step up, please? Your voice will carry some weight.
Dalai Lama - any comments on the moral responsibility here?
See wikipedia's article on the "Precautionary Principle".
http://en.wikipedia.org/wiki/Precautionary_principal
The have no right to do this. Let them scratch their heads over their scientific scribbles without putting all the Earth in danger.
Posted by Quite Well Acquainted With Physics, 29 Jan 2009
Seriously
even with all the ramifications of mild possibilities of minute, less than one second black holes I say plug it in and let all these doomsday folks sit and watch. The possibility of creating a blackhole that would cause significant damage is so astronomical, it's worth the risk.
Posted by PJ, 30 Jan 2009
Pull the plug
I posted a suggestion at www.whitehouse.gov that the National Security Council should advocate for the termination of the LHC, by way of this link: http://www.postmarks.com/blackhole
Posted by randy james, 29 Jan 2009
B4K4
For anyone who buys the poison kool-aid, Super Colliders have existed for a long time now. CERN just happens to have the largest. Fermi Labs happens to have a pretty large Super Collider (Largest running until LHC is up and fully functional). Anyone who believes this is replicating the "Big Bang" is also high on some narcotic. For the Big Bang to be replicated via current theory we would have to somehow re-create the "Super Force" and since we are a long way from having a real "Theory of Everything" that's not happening just yet.
Posted by medv4380, 30 Jan 2009
Does the LHC out do nature's extremes?
I take comfort in not knowing of stars the sun or planets disappering, as if from an unknown reason, into a black hole.
Posted by Oliver Hollister, 31 Jan 2009
misrepresented
This article misrepresents the research paper posted on arXiv. For instance, the ABSTRACT concludes with the sentence "Based on this analysis, we argue against the possibility of catastrophic black hole growth at the LHC." The authors of this paper do not claim that their research "raises serious LHC safety doubts." On the contrary, they claim that, based on a particular (and experimentally unverified) string theory model, catastrophic black hole production "doesn't seem possible."
Of course, theorists have been known to make mistakes, and even though nearly everyone in the field agrees that catastrophic black hole production at the LHC is impossible, they COULD all be wrong. However, there's a much simpler argument proving that the LHC cannot cause a catastrophe of this nature, which is just that cosmic rays have not done so in the 4+ billion years that the earth has been in existence. Some cosmic rays can have energies up to a million or so times the collision energies at the LHC, and yet over all that time, no catastrophic black holes have been created (clearly, since the Earth is still here.)
Anyway, for more details from better informed people, see:
http://public.web.cern.ch/public/en/LHc/Safety-en.html
Posted by Ben, 31 Jan 2009
Earlier paper by two of this papers contributors could suggest there's still room for danger..
I would say the safety concern is more severe than the authors of the above paper make out. Infact, they still don't see a possible risk.
In another paper that was published in 2002 by R Casadio and B Harms (pre-print http://arxiv.org/abs/hep-th/0110255v2), it was argued that it is possible under the same, so called - Randall-Sundrum theory - for a micro black hole to last atleast 30 years. So what happened to that prediction? Still covered by the more moderate looking >>1 sec claim I suppose.
The danger issue would still relate to the rate of evaporation over this time; when compared to the rate of accretion. According to the astrophysicist Rainer Plaga (see http://arxiv.org/abs/0808.1415v2), on a point seemingly challenged by this new paper, the mbh would only need to reach a mass of around 1kg for the conventional Hawking/Beckenstein derived luminosity to begin to be partially applicable here because of the 'warped' phase of the Randall Sundrum theory.
In the conventional world, the power output of this is most extreme at the lower end of our supposed, larger, non-warp/string theory-like size of scale. The value of Hawking radiation given for 1kg mbh if within the larger non string scale seems to give
an unimaginable 10^32 W. But a supposedly credible estimate given by Plaga and based on applying the Casadio/Harms 2002 approach, the power from a 1kg mbh here WITHIN the warp scale would be a colossully dangerous 5.2^16W. Anyone who wishes to, could confirm the first value atleast by looking under wiki Hawking radiation for the luminosity.
If you've recovered from that, unless you don't believe a word of this while your not checking me up, there is another issue that is puzzling about this recent Casadio et al paper. It claims that the net angular momentum of the mbh would be zero after randomly directed accretions from particles approaching it. This seems to refer to the overall average of change in angular momentum for the mbh over time. Surely then, it does not imply that at any given time the angular momentum would actually be likely to be zero!
But why am I talking about the angular momentum of micro black holes?
Because, curiously enough, in yet another paper of Casadio/Harms (Physical Review D Vol 64, p24016, 2001) it is claimed that mbh's with angular momentum can REDUCE OR EVEN ANNUL the potential for evaporation of the mbh!
It's not to say these physicists haven't raised serious issues in their work. Along with a number of others, after comparative evaluation, they have pointed out that the correct applied mathematical approach to micro black hole radiation/evaporation would be the 'microcanonical' one as opposed to the 'canonical' approach that is used by the CERN safety group and another earlier safety paper. This is one of several criteria (also angular momentum, 'back reaction', higher numbers of extra dimensions) thought to end up making the mbh duration longer - atleast for certain specific 'quantum gravity' theories.
Would you believe then, that Stephen Hawking and others dealt with this in 1978, when it was argued that the canonical approach was inappropriate? Try looking at this, I still can't quite believe how bad it makes CERN's safety people look myself..
'.. the attractive nature of gravity and the possiblity of having a black hole cause the canonical ensemble to break down. One would expect that this problem could be overcome by the use of the microcanonical ensemble.'
S Hawking/MJ Perry/GW Gibbons Jan '78
(see http://books.google.co.uk search for 'Euclidean Quantum Gravity', then Find 'microcanonical': first result).
Scandalous neglect by the CERN safety people?
Surely.
But I believe Casadio/Harms have become afflicted by a strange wishful thinking and excitement that seems to affect many physicists today.
Take such a title as 'High energy colliders as black hole factories: The end of short distance physics' and no, this one is not a disaster scenario paper.
Is there any sensible basis for such excitement?
Cosmic ray detectors in Argentina that include the new Pierre Auger detector, can analyse considerable numbers of cosmic rays with energies of upto 1,000,000 x that available for proton proton collision at the lhc. There are two papers, thru google scholar, that argue such detectors could detect evidence for even micro black holes emerging from them. [search: black holes cosmic detector].
So with only the opportunity to run vastly (10^7 x) more collisions than any human eye will be even given the opportunity to inspect - after extensive computer 'filtering' (Nature, Jul, '07) - I cannot even see a clear scientific basis for operating the lhc and hence no basis whatsoever, given the other clear economic, environmental (equivalent power supply per year for city of Geneva) and possibly vast safety costs.
Posted by Eric, 29 Jan 2009
hahaah Tankers...
Ok, so I just realized after reading some of these comments that 1) they are copy and pasted on any articles involving LHC... and 2) They have the same format as Tankers, who has been going around spouting the same stuff for a long time. Credibility suddenly is lost.
Posted by Shawn, 01 Feb 2009
Answer
Only God Knows!
Posted by Mickey, 08 Aug 2009
Black Holes--what are they?
Correct me if I'm wrong but isn't a black hole a region in space where the gravity is so strong that nearby mass and even electromagnetic radiation gets sucked in thereby creating a stronger gravitationbal field which sucks more stuff in? Then, it sucks more and more growing stronger until someday it has a galaxy of its own. Drifting into space harmlessly sounds out of character to me.
Posted by Ron, 02 Dec 2009