There's a very detailed and carefully argued article by a US Assistant Professor of Law about the LHC and safety concerns available at arXiv. (It would seem the article is to appear in the Tennessee Law Review, but I can't see if Glenn Reynolds of Instapundit fame, who is a Tennessee Law Professor, has noted it yet.)
It's very long, and I have only looked through the first half, but it seems very careful and accurate in its summary of the history of the scientific debate over its safety.
It even covers the concerns of Rainer Plaga, and agrees with my view that they never seem to have been adequately addressed.
The arXiv blog summary of the article is here. Both it and the original article are well worth a read.
UPDATE: hey, I've been Instapundit-ed! Thanks, and welcome all. There's a lot of old posts here about the LHC and black holes, but sadly you have to use the somewhat erratic search function to find them. (Why can't Google perfect search within the very blogs it owns?)
"I can't see if Glenn Reynolds of Instapundit fame, who is a Tennessee Law Professor, has noted it yet.)"
ReplyDeleteHe has now.
Hello; found your post on Glenn Reynold's blog.
ReplyDeleteThere's misinformation about the LHC's capacity to create a black hole that would threaten the planet's existence. First of all, FermiLab's Tevatron has already been operating at smililar magnitudes of energy as the LHC (when comparing proton collisions) and in 2 decades of operations has yet to create a singularity capable of consuming the planet.
Second, if you lay aside the speculative theories and simply sit with what the physics community already knows, then the LHC is not powerful enough to produce the sort of microsingularities that are the center of discussion.
Third, even if you presume the highly speculative theories are correct, when you do the math, you'll see that the maximum mass of an LHC produced singularity would be 2.5x10^-14 grams (25 femtograms), which would result in an event horizon many orders of magnitude smaller than a single proton. This translates into a very limited ability to actually capture matter. See the following link for further info about such a singularity's ability to affect nearby matter:
http://startswithabang.com/?p=878
And while we're at it, when you do the math, a black hole so small would would only last fractions of a second before decaying into elementary particles. In short, they'd evaporate very, very quickly. In fact, here's where we get an indication that the speculative theories have a flaw: A 25 femtogram sigularity would evaporate off via Hawking radiation in 1x10^-66 seconds. That's smaller than the Planck time (10^-43 seconds) which is the smallest unit of time that has any physical meaning. Or in short, the evaporative time is smaller than the smallest possible unit of time according to physical laws. And this indicates a problem with the theory predicting the creation of these singularities to begin with.
Fourth, and again, even if you grant that the speculative theories are correct, the LHC is still only maxing out at 14 teraelectron volts (TeV). Cosmic rays on the order of 400 TeVs hit the earth all the time and still don't cause the effect critics like Plaga and others are concerned about.
Now, I don't intend to suppress good natured and honest criticism of any scientific project, including the LHC. When a concern is raised, it should indeed be answered. It's a good thing for citizenry to ask questions and request that concerns be addressed. But that is what I'm trying to do here: Answer concerns. The criticisms being raised don't take into account the entirety of the physics that's known, and even when you grant credence to the speculative theories suggesting the possibility of a micro black hole, you discover that those speculative theories predict a singularity so small and so extremely short lived that it would have basically zero effect. That's if the theories are correct. And in nature, the planet is bombarded with collisions well above the energies the LHC produces, and no planet-consuming singularity has been produced yet. The point is that raising concerns is healthy for knowledge, but the concerns in this particular instance have been demonstrated to be unwarranted.
Still, though, it's good to see that people care and pay attention to what's happening around the world.
FermiLab's Tevatron has already been operating at smililar magnitudes of energy as the LHC (when comparing proton collisions) and in 2 decades of operations has yet to create a singularity capable of consuming the planet.
ReplyDelete"Yet" !
OMG !!!
""Yet" !
ReplyDeleteOMG !!!"
LOL! Yeah, when they hit that 3rd decade, we are so screwed. :D
To Anonymous 2:34 am:
ReplyDeleteI have no idea if you are right or wrong, but I cannot recall reading such a well-written and *reasonable* post on any subject anywhere.
Kudos.
My own comments tend to stray towards the polemical, so/but ditto to Anon/7:04AM.
ReplyDelete(Why "Anonymous," people? Can't you just enter some name, any name?)
Yes Anon, you raise good points, and I understand that it is only if theorised 'extra dimensions' exist that there is any prospect of a mini black hole being created at all.
ReplyDeleteRainer Plaga's concerns are also, as I understand it, only valid if a certain model is correct.
But your point about cosmic rays falling on earth is not an exact analogy to the situation at the LHC, and as I understood it, that is why the (last minute) safety review paper concentrated on the long existence of neutron stars as proving they can't be a danger.
Plaga thinks he has found a case where even that may not be conclusive proof of safety, and I suspect he has not been adequately answered.