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Quark-gluon plasma

  1. Feb 24, 2010 #1
    The Brookhaven National Laboratory's website has a news item on 'Hot Quark Soup' which seems to mean quark-gluon plasma. (http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=1077) The article refers to "this remarkable form of matter, which last existed some 13 billion years ago".

    At CERN, the LHC ALICE investigation intends to create/study quark-gluon plasma. But the CERN website says "Whatever the LHC will do, Nature has already done many times over during the lifetime of the Earth and other astronomical bodies." (http://public.web.cern.ch/public/en/LHC/Safety-en.html)

    I'm not knowledgeable in this area but these statements seem to contradictory. What am I missing?
  2. jcsd
  3. Feb 24, 2010 #2

    Physics Monkey

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    My first advice is, don't take these press releases too seriously, they're not necessarily trying to be consistent with each other. They are trying to sound cool.

    Nevertheless, here is my attempt untangle the two excerpts:

    The first statement refers to the last time in the universe's history that basically the whole universe was a quark gluon plasma.

    The second statement refers to the fact that high energy collisions are constantly occurring in an uncontrolled way due to cosmic rays, etc. These collisions can sometimes produce a momentary fireball analogous to that at RHIC or LHC, and this fireball may contain a tiny bit of quark gluon plasma.

    Hope this helps.
  4. Feb 24, 2010 #3


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    Hi BrianL,

    Take a look here: https://www.physicsforums.com/showthread.php?t=251509&page=5"

    Posts #89 - #92 jal's thread covers what you are asking about in greater detail...

    Also, check out jal's blog on the subject.

    Good luck...

    Last edited by a moderator: Apr 24, 2017
  5. Feb 24, 2010 #4
    I agree you shouldn't take press releases too seriously, but I don't think there's actually a contradiction here. The Brookhaven website is talking about heavy ion collisions at RHIC, where large nuclei are collided. The size of the system (potentially) allows for an approximately locally thermalized system (a quark gluon plasma) to exist for a short period of time. I'm not entirely sure, but I guess it may be reasonable to think that such a system has never existed since the early universe.

    Although there will also be heavy ion collisions performed at the LHC part time (which is what Alice focuses on), most of the time it will be running proton-proton collisions, and this is what the website you quote is talking about. There was some concern raised (by non-physicists) that mini black holes or some such things might be created, and they said we couldn't rule out the possibility since we had never collided particles at this high energy before. Very high energy collisions of (small) particles such as these happen all the time in the upper atmosphere, however.

    There's been no such speculation about creating black holes in heavy ion collisions that will be at lower energy than the proton-proton collisions, although it's true that, strictly speaking, these exact kinds of collisions do not occur naturally.
  6. Mar 3, 2010 #5
    According http://www.iop.org/EJ/article/1742-6596/78/1/012023/jpconf7_78_012023.pdf" [Broken] (section 2) QGP can exist also in cores of the neutron stars. Maybe The Brookhaven National Laboratory's website wants just say "It's quite real sure QGP existed at the beginging of universum" but doesn't mention QGP's existense at nowadays, because it's not absolutely sure.
    Last edited by a moderator: May 4, 2017
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