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Comment by Taniwha | Hacker News Reader

The fact that the earth has seen these bombarding us regularly for millions of years does rather imply that the whole "OMG the LHC will make a black hole" panic was unfounded

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The best explanation of the LHC black hole issue I have ever seen was a The Daily Show interview which pegged the odds at 50/50:

Either it will. Or it won't.

The best part is around 3:00 in. http://thedailyshow.cc.com/videos/hzqmb9/large-hadron-collid...

while I agree with the general sentiment that the idea that the LHC will create a blackhole is silly, surely there is a difference between creating such a particle and simply being in the trajectory of a particle that has already been created.

The idea that it would create a black hole isn't silly, it could well do. The silly bit is the thought that it would be dangerous if it did, given particle collisions at higher energies than the LHC happen regularly in the atmosphere and there is nothing particularly special about the LHC ones, bar the fact they are in a massive detector.

Note: I also think the public's LHC worries were unfounded.

One way that the LHC collisions differ from cosmic ray impacts is that the center of mass velocity is much lower. If high energy collisions created small black holes, cosmic rays could make ones that simply zip past at escape velocity (because (lots+0)/2 is still lots) while the LHC ones are captured (because (lots+-lots)/2 can be tiny).

I don't think that follows. The LHC is many, MANY orders of magnitude too weak to produce this kind of thing, but it can produce beams of many protons or, alternatively lead nuclei. Thus, it could conceivably create entirely different effects.

Actually, it does follow. If there are particles of the energy described in the original link, there are many more particles of lower energies also hitting the Earth's atmosphere, including energies accessible at the LHC. And none of these resulted in the Earth's destruction.

The same logic applies to the argument that any black-holes or otherwise dangerous particles would simply zip by the Earth (stated in a sibling comment to yours). Particles of slightly lower momenta come in higher numbers, so these would produce the dangerous particle, but not retain enough momentum to escape. Since the Earth has not been destroyed, there are no particles produced at low enough energies for us to destroy ourselves.

If I understand you correctly, your argument is based on the assumption that particle energies have some sort of continuous distribution. That's not necessarily true.

It's based on the fact that particle energies follow a continuous distribution.

See, for example: http://www2.astro.psu.edu/users/nnp/cr.html.

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