I like the real world view, where parades of scientists develop consensus around the ideas of a few. For example, the earth is completely flat, and the center of the universe. It’s easy to forget how our whole species believed this, with the same conviction we believe black holes will evaporate with a puff of Hawking Radiation.

CERN is the first device with enough energy to create an artificial black hole. Unfortunately, there are those who object to all the new colliders, creating the impression of a paranoid fringe, proven to be scientifically ignorant. CERN is a very big gun, able to probe matter on the scale of the weak force, the first device with this level of energy. I honestly wonder if physicists are better informed than the paranoid fringe–it’s absolutely new territory.

If everything goes according to plan, black holes created in the matter stream will quickly evaporate as Hawking radiation. Though we have confirmed the existence of black holes, we have never observed Hawking Radiation, so there does seem to be a risk that a black hole might be stable.

I guess we will find out. Such is the way of the world, with big science and
big money, gathering solid political support. We freak-out if Iran has a nuclear program, but dismiss the minority report on dangers in high-energy particle
physics, as crying wolf. Will the real fanatics please stand up? Probably not.
Self-awareness is just what fanatics lack.

I don’t think cosmic rays are good model for what will happen at CERN.
At CERN we have much lower momentum, inside a closed system. If a stable black hole were formed, we could see the demolition of our planet
in less than ten minutes–the most efficient weapon ever tested, or the final industrial accident.

The current accepted theory is one where no proposed experiement is dangerous, and experimenters have a green light for any experiment they
wish to conduct at high-energy.

I am also enjoying this adventure, but believe France should be much more serious in matters of risk accessment. It is risk accessment–not risk–that is
nonexistent. Leading scientists should reflect on the history of science, where a minority of one, frequently leads to a breakthrough in scientific thought, by individuals who reject accepted theory. They should admit we have never been able to tell the difference between blowhards and geniuses, before a
particular view of nature runs its course–which often takes decades.

We have years before CERN’s collider is operational. Why not assemble teams of teams of physicists to play the devil’s advocate? There are certainly credible scientists who worry about the risks of probing matter at these energies. We should listen attentively to the minority view, given what is proven knowledge on black holes (self-propagating collapse of matter), and
what is theory (Hawking Radiation never observed, cosmic ray interactions never observed).

The brute force approach of big money, big names, big theory and a project of unprecedented scope, runs over opposition like a steamroller. I would like to see CERN go forward as much as anyone else–but waving our arms to dismiss the minority reports is reckless and irresponsible. Sometimes, what we don’t want to hear–ideas can only delay or harm the CERN project–are exactly what we should hear. For a few dollars more–a very small cost in relation to CERN’s budget, and allow ourselves the benefits of open-minded debate.

Could this kill the project? That’s the whole point of risk accessment!
CERN would not be stopped by objections that don’t hold water, but we might find chilling reasons to proceed with caution, or not at all. We really don’t know if the reflex is censorship, and anyone expressing concerns is percieved as a
menace to progress. In examining all the risks, we only employ more scientists, engineers, mathematicians–just what drives CERN in the first place.

What could definitely kill the project is the public perception that CERN experiments are recklessly irresponsible. Censoring those who urge caution
and reflection certainly creates this impression. The risk we dismiss so
easily is the utter destruction of our planet. If there was ever a good time to listen, it is right now.

There is another danger. Suppose a group of scientists develop a resolutely convincing model for stable black holes when CERN is operational? Any state or nation is well within it’s rights to nuke the facility, if they believe they are in grave danger. So, should scientists present their objections to CERN, or should they present their findings to host governments and military establishments?
We don’t know what discoveries will happen before 2010–CERN could very well be shut down at gunpoint, by states or nations who think the risks are too great. No nation, including France, has the right to put everyone in jeapordy.

For working scientists, what would you do with new research assigning a 92 percent probability of stable black holes forming in the particle stream? How about a 1 percent probability? CERN is not listening, so who gets your paper?

Every war in history is based upon smaller issues than complete destruction of
our planet. I really think we need greater consensus and less pomp in matters of risk accessment.

While reading Steven Hawking’s excellent book “Universe in Nutshell”, I was struck by how he characterized science in the information age. In his field, papers are being published at a continuous rate of 7 per minute. In terms of raw information, a professional physicist is marginally better informed than
janitors who mop the floor. The bias towards accepted theories, which are often wrong, is simply enormous.

I would love to see Dr. Hawking get a Nobel Prize when small black holes in the CERN particle stream disappear with a puff of Hawking Radiation. He’s really a wonderful guy. If we get a stable black hole, all life on earth–and the planet–would evaporate instead. The CERN project is certainly among the wonders of the world, but refusal of the French governent to explore and manage possible risks could be called insanity. I think every nation supporting CERN should insist upon exhaustive accessment of risks, and examine ALL relevant theories as if our lives depended on it (this might very well be true).

Lacking momentum, a heavy object like a stable black hole, would simply
sink to the earth’s core, where it would do what black holes are proven to do:
Eat all the matter the crosses an expanding event horizon. The CERN experiment will mass-produce black holes, which we hope will be unstable and disappear in nanoseconds, or less. If they do not, it will be our final experiment.

If France does not provide an atmosphere of careful risk-accessment, that doesn’t mean nobody else will. Our bias, proven to be enormous, for the entire history of science, could be our undoing. It is especially disturbing when we favor theory and seem to ignore established facts–or act as though working scientists are just trouble-makers, because they urge caution.

I guess I’m a little worried . . . (blab, blab, blab). Let me leave you with this thought for reflection. How many physicists, who believe that risk of a stable black hole is zero—also believe the universe was created a point of zero volume and infinite density? If you believe that, contrary to conservation of
mass/energy, it’s possible to believe in most anything. If physics is an experimental science–which is what CERN is all about–then we should base our perception of risk on experimental facts, not popular or accepted theory, having no empirical validation.

So if that’s not real, then what use are the accretion disks of risk assessment, and I find myself all over the map, but still trying to understand.

You have to remember that these are hard for the layman to follow. However, I note that Jacobson says this:

“To predict the state of the positive free-fall frequency modes T+ and T− from the initial state thus seems to require trans-Planckian physics. This is a breakdown of the usual separation of scales invoked in the application of effective field theory and it leaves some room for doubt[52, 30, 53] about the existence of the Hawking effect.

While the physical arguments for the Hawking effect do seem quite plausible, the
trans-Planckian question is nevertheless pressing.”

The paper he cites at 53 is the Helfer paper I originally mentioned. Thus, he does not seem to be dismissing it out of hand. (In fact, the other 2 papers he cites are earlier papers by Jacobson himself.)

Now, in section 7.1 which you specifically referred me to, I take it to mean (in a paraphrase) that string theory suggests that, at least for some black holes, there isn’t a problem with this trans planckian issue. However, the section finishes with this fairly opaque (to me) sentence:

” However, neither of these approaches from string theory has so far been exploited to address the origin of the outgoing modes, since a local spacetime picture of the black hole horizon is lacking. This seems to be a question worth pursuing.”

Correct me if I am wrong, but this seems to leave the question open somewhat, even if Jacobson seems to lean towards the idea that there really is no problem.

Now I think I may be coming to the heart of the issue. Your position is that:
“indeed if the calculations of black hole production are correct (requiring semi-classical gravity), then I expect the Hawking radiation results will also be reliable.”

However, it comes down to whether one necessarily follows the other. Are you saying that it is a matter of “calculations showing the possible creation of MBH also show that they must evaporate via HR” or is it more the case that if one happens, it suggests the other will also happen (or if you prefer, strongly suggests the other).

The way I read Jacobson, and your earlier comment, it is more the second case.

If my understanding is correct (and feel free to tell me I do not understand you or Jacobson correctly) then I would think that there is in fact sufficient reason to say a risk assessment should include the possibility of HR not occurring.

It is clear from all of this thread that there is a lot of legitimate speculation as to what the LHC might or might not reveal. Now, my concerns are not those that Dissident raised, because by his own argument, you can’t predict risk on something that is completely unforeseen and outside of your current “model”. However, unless I am misunderstanding you, you think the failure of HR would be extremely unlikely, but not impossible. But surely as long as it can be modeled, then risk assessment can be done. I think….

http://en.wikipedia.org/wiki/CP_violation

If there was ever an understatement previous to hindsight, the maybe :Let there be Darkness

just might be such an understatement?

T-violating muon polarizations, are as far as I am aware, beyond the standard model?

The experiments one can do by accelerating Particles, and colliding them is opposite the above:Blackhole’s created from Particles.

The “reverse engeneering” process needed to create conditions that are close to the big-bang, are all based upon “what we actually know”?

The inner products from accelerated particle collisions, are all quark oriented:
http://www.th.physik.uni-frankfurt.de/~gerland/stoecker/ger/node16.html

The fact that the “reverse” process is being investigated, is no way sure that there may be a particle phase that is not fully understood, and this does not rult out the appearance of some form of “NEGATIVE” phased matter?

Unfortunately the analogy is not exact. A cosmic ray particle moving at close to light speed hits an earth particle that is moving slowly with respect to earth. If this creates a mini black hole, it would be moving much faster than escape velocity from earth. If it accretes slowly like a neutrino it will zip right through earth with very low probability of hitting anything. It would have to accrete millions of particles to slow it below escape velocity, the probability of this happening even once in trillions of trials over billions of years is essentially zero. On the other hand, when two particles collide in a collider, their velocity more or less cancels. They would drop into earth and have forever to accrete. There are several possible accretion mechanisms.

Actually, “more or less cancels” happens only occasionally. The collision of consequence is the collision of the quarks, and they carry a random proportion of proton energy. This is expressed in proton structure functions. Landsberg did some calculations, and I have been working on replicating them, that show that a bunch of black holes per year would be moving at less than escape velocity.

I would love to have someone help check the math behind these statements.

Incidently, the collider / cosmic ray analogy does suggest that accelerators producing particles that hit fixed targets would be safe. These might be used to explore higher energy ranges first.

While roaming the internet I have come across another paper: http://arxiv.org/PS_cache/gr-qc/pdf/0408/0408009.pdf which again is so technical as to be impossible for me to follow the detail. However, it does contain these lines:

“As the known equations of quantum fields in curved space-times are expected
to break down at such wavenumbers, the derivation of the Hawking radiation has the flaw that it applies a theory beyond its region of validity.” And:

“Therefore, whether real black holes emit Hawking radiation remains an open question and could give non-trivial information about Planckian physics.”

It may be that I am misunderstanding this paper, but it seems to be suggesting that HR works under certain assumptions, but there are other possible assumptions that may make it not “work”.

How these “assumptions” relate to MBH that might be created in the LHC, I don’t know.

My earlier question about black hole “remnants” also is left open. I am not sure if your earlier post means that you don’t think they will happen at all. However, if they do happen, as some say is a possibility, will they definitely not interact with matter (or each other) in any way that could be dangerous? ( I am expecting that they won’t be dangerous, but just asking!)

I know that you may not have time to address all these issues in detail right now. But, I suppose the fundamental point that Blodgett is making is that if there is any legitimate theory work which suggests that MBH may not disppear due to HR, and there is no “real life” observations to confirm it one way or the other, should not the risk assessment for LHC have looked at this scenario and spent time on the issue of “worst possible” accretion rates for a MBH (or indeed, hundreds of them) in the earth?

Just to be clear here: no one seems to think there is any chance at all of accretion rates being so high as mean the earth would disappear in a day, a year or even a thousand years. However, if it was barely possible within (say) 10,000 or 100,000 years, how would people would think about it then?

And also to be clear: the cosmolgical argument (about “naturally” created MBH not causing apparent problems) might “win” the risk issue for LHC too, but I think (as a layman) that Blodgett proposes interesting criticisms of the analogy that (as far as my internet searching so far indicates) have not yet been addressed in any published detail.

What I hope is not happening here is analogous to the way the first Shuttle disaster happened. Namely, a few people recognized a possible danger, but their concern got lost in the clamour to get a project going. (Not a perfect analogy, as Blodgett has apparently not got any actual physicist perfectly on side!) But you get my drift.

Do you think this risk assessment, was ongoing from 1955, from the time of divergence and from how cosmic analysis took place, plays a key role?

I mean, I see gravitatinal waves predominante in our views of acceptance, yet, the move to extra dimensional understanding, far from understood from those who critize string/M theory’s work.

Have I missed something here?