Large Hadron Collider Concerns

Discussion in 'Astronomy, Exobiology, & Cosmology' started by __your_Zahir_, Aug 10, 2008.

  1. Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    About once in the life of every scientifically advanced planet?
     
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  3. rpenner Fully Wired Valued Senior Member

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    As LC demonstrates -- a complete ignorance of relativistic kinematics.

    The upper energies of Cosmic rays (protons and other nuclei) are so powerful that they hit terrestrial matter with greater center-of-mass energies than the LHC's head-on collisions. So all the phenomena to be seen at the LHC have already happened -- just not where our detectors were pointed.
     
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  5. Lamont Cranston Registered Senior Member

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    Forgive my crass ignorance, can you educate me? How can the energy of a particle hitting earth ever be equivalent to two protons colliding head on at 99.9999% light speed? Give me a simple worked example and I'll be happy.
     
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  7. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    What's important is what's called the center of mass energy in the collision. The proton proton collisions will be occurring at roughly 14 TeV. If you don't know what "TeV" means, just take it as being a unit of energy. This is about \(14\times10^9\) eV, whatever an "eV" is. Collisions in the upper atmosphere have been observed (http://www.auger.org/) in excess of \(10^{12}[\tex] eV. So we're really a long way away from the highest energy cosmic rays that have been bombarding Earth for, oh, 4 billion years or so.\)
     
  8. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    The relevant particles aren't emitted from the sun, and in fact, no one really knows WHERE the ultra-energetic particles are emitted from. There was a paper claiming a correlation between these particles and what astronomers call "Active Galactic Nuclei", but I think that the work is still being questioned.

    See the link above. They have several well-written explanations about cosmic rays.
     
  9. Lamont Cranston Registered Senior Member

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    Many thanks indeed, Ben.. But in the LHC we potentially have 600,000 collisions/s happening in a small area at the same time, if my understanding of collider operation is correct. Does this proximity and concentration of collisions happen in nature.
     
  10. camilus the villain with x-ray glasses Registered Senior Member

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    http://news.yahoo.com/s/ap/20080910/ap_on_sc/big_bang

    Massive particle collider passes first key tests
    By ALEXANDER G. HIGGINS, Associated Press Writer

    GENEVA - The world's largest particle collider passed its first major tests by firing two beams of protons in opposite directions around a 17-mile (27-kilometer) underground ring Wednesday in what scientists hope is the next great step to understanding the makeup of the universe.

    After a series of trial runs, two white dots flashed on a computer screen at 10:26 a.m. (0826 GMT) indicating that the protons had traveled clockwise along the full length of the 4 billion Swiss franc (US$3.8 billion) Large Hadron Collider — described as the biggest physics experiment in history.

    "There it is," project leader Lyn Evans said when the beam completed its lap.

    Champagne corks popped in labs as far away as Chicago, where contributing and competing scientists watched the proceedings by satellite.
     
  11. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    The Pierre Auger announced last November that the nearby AGN were the probable sources of the 100 highest energy cosmic rays [protons], as there was a strong correlation between those locations in the sky, and the apparent point of origin of the highest-energy particles. They calculated that the correlation was simply due to chance at about 1%; further studies are continuing to narrow that down. Google reveals hundreds of articles on it.

    The COM energy of an energetic incoming cosmic ray striking a stationary particle that would be comparable to the 1,000+ TeV COM of the Lead collisions would be about E18 eV. LC is correct, however, that these are single events in nature, whereas the LHC would have multiple events in a very small volume. That is essentially the Paul Dixon concern.

    Even ignoring that concern, the LHC would collide Lead-on-Lead, which does not happen in nature at those energies; but rather proton-on-Lead [assuming that the reported high-E of those rare cosmic rays is correct - some have questioned those values as to whether they are even reliable] , which could be why we don't create strangelets in nature. However, that might be disproven if the AMS-2 is launched in 2009 and attached to the ISS and detects strangelets, showing that they exist in nature, and we won't make them for the first time at the LHC when Lead collisions commence.
     
  12. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    It doesn't matter. It's only the center of mass energy in each collision that is important.
     
  13. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    Multiple collisions in a small volume, but an exceedingly small chance of multiple collisions at 14 TeV happening in a small volume. Surely, Walter, during your undergraduate degree in nuclear physics you learned something about parton distribution functions?
     
  14. Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    From Wiki on High energy cosmic rays

    Cosmic rays with even higher energies have since been observed, among them the Oh-My-God particle (a play on the nickname "God particle" for the Higgs boson), observed on the evening of October 15, 1991, over Dugway Proving Grounds, Utah. Its observation was a shock to astrophysicists, who estimated its energy to be approximately 3 × 1020 electronvolts (50 joules)— in other words, a subatomic particle with macroscopic kinetic energy equal to that of a baseball (142 g) thrown at 100 km/h (60 mph).
     
    Last edited: Sep 11, 2008
  15. Lamont Cranston Registered Senior Member

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    But I'm still thinking that collisions of these energies do not happen in such large concentrations in nature as they do in the LHC, in fact no concentrated collisions of that kind have been observed before. So I do feel that it's naughty of CERN to say that their collisions can be compared with what happens in the natural world. They are an unknown quantity and it should be admitted publicly
     
  16. Lamont Cranston Registered Senior Member

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    So how heavy would the particle be, and how fast would it have been travelling?
     
  17. Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    They think it was a proton.
    They didn't have much time for careful examination.
    Speed 99.999.......% c
    Someone with better maths than myself may work out how many 9s, but fast enough surely to have the same effect on any particle it hits as the two far less energetic LHC particles have on each other.
     
    Last edited: Sep 10, 2008
  18. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    Yes, agreed, most collisions would not be head-on. I simply pointed out that that was Dixon's concern, not that I found it compelling. But why don't you work out the energy distributions for us?
     
  19. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    Because I hate nuclear physics. And parton distribution functions are really freaking complicated. But (assuming your interest was genuine and not just to test me as to whether or not I knew what I was talking about) you can find all the information you need here: http://www.phys.psu.edu/~cteq/.
     
  20. Lamont Cranston Registered Senior Member

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    You mean....something like the things rattling around the LHC but with a '9' or two difference in velocity...?

    I hope those two lonely LHC operatives are equipped with baseball bats as well as state-of-the-art protective clothing. :jawdrop:
     
    Last edited: Sep 10, 2008
  21. Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    Those 9's represent a lot of extra energy.

    I'm not sure why Walter believes that the concentration of collisions will make a difference. Some kind of chain reaction?
     
  22. nietzschefan Thread Killer Valued Senior Member

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    That would be pretty funny if this 4 Billion dollar machine went back in time even 30 seconds and was found a little beyond high orbit, where the earth was at that time.
     
  23. Lamont Cranston Registered Senior Member

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    More collisions give a Bigger Bang
     

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