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Will particle accelerators destroy the Earth?

  1. Sep 16, 2006 #1
    'An accelerator usually consists of a vacuum chamber surrounded by a long sequence of vacuum pumps, magnets, radio-frequency cavities, high voltage instruments and electronic circuits. Each of these pieces has its specific function.

    The vacuum chamber is a metal pipe where air is permanently pumped out to make sure the residual pressure is as low as possible.

    Inside the pipe, particles are accelerated by electric fields. Powerful amplifiers provide intense radio waves that are fed into resonating structures, the Radio-Frequency (RF) cavities. Each time the particles traverse an RF cavity, some of the energy of the radio wave is transferred to them and they are accelerated.

    To make a more effective use of a limited number of RF cavities, accelerator designers can force the particle beam to go through them many times, by curving its trajectory into a closed loop. That is why most accelerators will look roughly circular.

    Curving the beam's path is usually achieved by the magnetic field of dipole magnets. This is because the magnetic force exerted on charged particles is always perpendicular to their velocity - perfect for curving the trajectory! The higher the energy of a particle, the stronger the field that is needed to bend it. This means that, as the maximum magnetic field is limited (to some 2 Tesla for conventional magnets, some 10 Tesla for superconducting ones), the more powerful a machine is, the larger it needs to be.'
     
    Last edited: Sep 16, 2006
  2. jcsd
  3. Sep 16, 2006 #2
    Not one proton - more like 10^18 of them. Of course a charged particle is easily stopped by ordinary electronic matter (think alpha particles and the sheet of paper, or gold foil); 100keV ~ 10^-13 Joule is (by itself) nothing really; but with large beams at TeV level -

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

    Equivalent of 0.17 ton TNT in the beam, and 25 ton TNT in the superconducting magnets. Not quite earth-shattering.

    Use - 1 electron-volt ~ 1.6x10^-19 Joule
    1 ton TNT ~ 4.2 GJ
     
    Last edited: Sep 16, 2006
  4. Sep 16, 2006 #3

    HallsofIvy

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    But what does anything you've said have to do with "Will particle accelerators destroy the earth"?
     
  5. Sep 16, 2006 #4
    i think he cut and pasted and forgot his original question,
     
  6. Sep 16, 2006 #5
    Look at the edit times in the UR corners - he posted at 0129, I replied at 0144, and then he deleted his question at 0343 for unknown reasons. HallsOfIvy came in at 0503.

    He had attributed the pasted excerpt to the CERN website.
     
  7. Sep 17, 2006 #6
    Probably something about creating black holes
     
  8. Sep 17, 2006 #7
    I thought my question to be poor so I erased it and simply left the interesting CERN excerpt for those interested, as I was, in how accelerators work.

    The question was what would happen if the accelerator's dipole magnets suddenly turned off and the particles inside were no longer bent to the loop's curvature. Would the particles, say protons, penetrate the walls of the accelerator or would they merely glance off them with no damage? Rach pointed out how stupid my question was because protons are charged and thus easily repelled by the walls.

    Now I ask the same question but with a relativistic neutron of 100KeV, would it penetrate the accelerators walls and cause a catastrophe?
     
  9. Sep 17, 2006 #8
    A relativistic neutron won't cause a catastophe. You get cosmic rays hitting the earth with very high energies every day.

    http://www.ast.leeds.ac.uk/haverah/high.shtml

    But referring to your title, I do feel uncomfortable about phrases like "probing energies not seen since the big bang".
     
  10. Sep 17, 2006 #9

    DaveC426913

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    I wrote this as a short story many years ago! If you made a collider powerful enough to probe energies like in the Big Bang, you would actually recreate said Big Bang, with ... destructive results.
     
  11. Sep 17, 2006 #10

    ZapperZ

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    How would it be possible to make a collider powerful enough to recreate the exact energy in the Big Bang? Think about it - ALL of the energy in the universe right now all compressed into such a collision. BY DEFINITION, the matter that made up the earth and the accelerator will not be part of it.

    I think people get carried away with this whole thing without thinking it through. First of all, contrary to popular claims even from some of these particle collider website, what is being created is more closely defined as the energy density that approaches (still several order of magnitude away) what was thought to be the similar parameters that of the BB. Compare to the BB, the total energy being scale used in such human facility is miniscule!

    Secondly, you also need to give us a little bit of credit for our intelligence. Even before any plan of making any kind of collider, a very stringent safety envelope is required. This includes the energy scale of a collision, all possible by product of such collision, the result of such energetic particles hitting the beam pipe, etc.. etc. There are people who majored and work in such fields related to health physics that do this full time. You have to know such things because one needs to make an effective shielding and take necessary steps in terms of safely operating such facility.

    Take note that, in the US, there is a standing policy from the DOE that if something cannot be done safely, from the perspective of the work participants, the general public, and the environment, then it cannot be done at all. So you can bet that if a particle collider cannot be designed in such a way that it poses no threat, be it immediate or not, it will not be constructed.

    Pet peeve: particle accelerator does not automatically equal to particle collder.

    Zz.
     
  12. Sep 17, 2006 #11
    About possible destructive experiments, is someone in the world planning to make micro black holes in laboratory?
     
  13. Sep 17, 2006 #12

    DaveC426913

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    I do not think this is true.
    1] You're thinking about the Big Bang and universe as if it is a zero sum. There are some hypotheses that posit that the entire universe popped into existence from nothing (not the technical term), such that the initial Big Bang was not simply a very dense collection of all the energy in the present universe. There are also hypotheses that the initial mass of the BB was a mere 25 pounds, and all the rest of the mass in the universe came from residual energy (bah, I'm spouting gibberish, I know. The references are in Brian Greene's latest book).

    2] You're presuming there can only be one Big Bang at a time. Who says you can't create a new one in an existing universe? There are hypotheses that propose this.

    3] In my story, the Big Bang was basically rolled backwards. i.e. the device that was made caused a contraction that sucked the universe (including the Earth) in, sort of like a colossal black hole. So, yes, ultimately, my BB did include the mass of the Earth.


    An odd thing to say. When did I ever make comment on anyone else's intelligence? You don't think I'm some sort of writer do you? It was a class. I was half the age I am now.

    My story was not not a simple accelerator/collider device causing a snowball reaction. My story was more Asimovian - a zillion years in the future, the "device" was the size of an asteroid and had taken hundreds of years to build. The purpose of the device was to actually create the conditions at the Big Bang, where all the forces join.

    In short, it was fantasy, not sci fi.
     
  14. Sep 17, 2006 #13

    ZapperZ

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    I'm not talking about before or at the moment of the BB. We have no physics on that, and invoking quantum fluctuation is very flimsy. I'm talking about the total energy of the BB itself after creation. Unless you are arguing that total energy of the universe isn't conserved (more or less) at that point, then I will put it to you that there's nothing we can create here on earth that will have a total energy even remotely equivalent to what was there then.

    I was making a generalized response, not to your post in particular. I should have made my reply clearer.

    Eeek. Then you shouldn't have brought it up, since one can easily interpret as if you're offering an agreement or explanation.

    Zz.
     
  15. Sep 18, 2006 #14
    If we are creating energy densities in labs on the order of small black hole singularity energy densities, why do they fizzle out and not grow?
     
  16. Sep 18, 2006 #15

    DaveC426913

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    Because they don't feed it a constant supply of matter?


    . . . . . . . . . . . . . . . . .
    .. . . . . . . . . . . . . . . ..
    .. .Please do not feed . .
    . . .the black holes. . . ..
    .. . . . . . . . . . . . . . . ..
    . . . . . . . . . . . . . . . . .
     
    Last edited: Sep 18, 2006
  17. Sep 18, 2006 #16
    Last edited: Sep 18, 2006
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