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Another Way the LHC Could Self-Destruct

Posted by kdawson on from the no-physics-whatsoever dept.

KentuckyFC writes "Just when you thought it was safe to switch on the LHC (though it won't be for a while yet), another nightmare scenario has emerged that some critics worry could cause the particle accelerator to explode. The culprit this time is not an Earth-swallowing black hole but a 'Bose supernova' in the accelerator's superfluid helium bath. Physicists have been playing with Bose Einstein Condensate (BECs) for over 10 years now. But in 2001, one group discovered that placing them in a powerful magnetic field could cause the attractive forces between atoms to become repulsive. That caused their BEC to explode in a Bose supernova — which they called a 'Bosenova,' a name that fortunately did not catch on. This was little more than a curiosity when only a microscopic blob of cold matter was involved. But superfluid liquid helium is also BEC. And physicists have suddenly remembered that the LHC is swimming in 700,000 liters of the stuff while being zapped by some of the most powerful magnetic fields on the planet. So is the LHC a Bose supernova waiting to go off? Not according to the CERN theory division, which has published its calculations that show the LHC is safe (abstract). They also point out that no other superfluid helium handling facility has mysteriously blown itself to pieces."

9 of 367 comments (clear)

  1. bad physics, bad press by Goldsmith · · Score: 5, Informative

    An expanding BEC isn't anywhere close to a supernova. This would be similar to snapping the valve off of a liquid helium tank. The guys at CERN could blow themselves up with this, but that's about it. They could blow themselves up lots of ways.

    It was called a "bosenova" because it shrinks before it expands, not because it's super destructive.

  2. Worser by hcg50a · · Score: 5, Informative

    Could it be worse than melting a 40-ton magnet, which actually happened?

    --
    HCG 50a = 2MASX J11170638+5455016
    11h17m06.4s +54d55m02s
  3. Re:First Law? by Scubaraf · · Score: 5, Informative

    Excellent point. Add to that the fact that superfluid helium is not a uniform Bose-Einstein Condensate and you have full debunking.

  4. Re:Phase change by geckipede · · Score: 5, Informative

    Helium isn't explosive, it's the most inert material you can get. If you want to make it explode it's going to have to be taking in energy from the magnetic field it is in, so the LHC's helium can never explode any more powerfully than a loss of superconductivity in the magnets would do anyway. Conservation of energy.

    also, lolwtfsig

  5. Cassandra's predictions were right by Reality+Master+201 · · Score: 5, Informative

    That's the point of the myth: Apollo granted her the gift of prophesy, then cursed her by making it so nobody would ever believe her predictions.

  6. Re:More Cassandra warnings... by Bob+The+Cowboy · · Score: 5, Informative

    oh and BTW, the windshield is necessary to allow a human driver to continue breathing at today's highway speeds. it's very hard to properly exhale at 50-60 mph.

    Uh huh. And the various (admittedly foolish) motorcycle drivers I see riding on their bikes at 80mph without helmets are just holding their breath?

  7. Re:First Law? by sdpuppy · · Score: 4, Informative
    Exactly. Besides, isn't it rather difficult to make a Bose-Einstein Condensate - you need to be fractions of a degree close to absolute zero, the liquid helium used is hotter than that, like 1.9K.

    In addition, magnets have been run at that temperature before.

  8. Re:Phase change by geckipede · · Score: 4, Informative

    Ah yes, I had forgotten that, there is a pretty hefty heat gradient allowing the helium to take heat energy from the surrounding environment. Still the point stands that there is a limited supply of energy available, it's never going to be a craterworthy explosion. I wouldn't want to be standing nearby if it did get a coolant rupture though... I have a mental image of the "I am invincible!" scene from goldeneye.

  9. Re:I was worried, but am ok now by ultracool · · Score: 4, Informative
    Maybe I can explain it, since I work with BECs. Whether atoms repel or are attracted to one another depends on the magnetic field they are in. A Feshbach resonance is a kind of magnetic field resonance at which the strength of attraction or repulsion is enhanced. If you set the magnetic field to a value where the attraction is strong, you can get a Bosenova (and yes, the name DID stick). You can have resonances at many magnetic field values, not just high ones. Most alkali atoms have a dozen or more resonances in the range of hundreds of gauss, so a really high magnetic field isn't anything special. The way Feshbach resonances work is by tuning hyperfine splitting. Helium-4 has no hyperfine structure and the atoms repel one another, therefore you can't force them to be attractive by tuning the magnetic field.

    I don't know how this FUD even came up. It's such a ridiculous idea to begin with.