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Ken Bloom | USLHC | USA

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More exciting than politics!

Some weeks ago, New York Times columnist Gail Collins wrote a piece about the possibility of black-hole production at the LHC.  I think she took this far too seriously; the chance of the LHC making black holes is super-tiny, and these aren’t the sort of black holes that are going to eat anything anyway.  Today Collins (who really is one of my favorite columnists, very trenchant political commentary) returned to the matter.  This time she did talk to an actual physicist, Brown’s Greg Landsberg, who is the US CMS physics coordinator.  She’s still too hung up on it, but at least she gave us some publicity for the big September 10 date, and even said that LHC startup will be as exciting as the upcoming Democratic and Republican conventions.  For sure, it will be more suspenseful!


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4 Responses to “More exciting than politics!”

  1. Harry Wertmuller says:

    Reasons “civilians” take black hole risks “far too serioiously”:

    1. So many physicists salaries and lives are dependent on the LHC

    2. Physics is a mess. Science is always a mess. Competing theories. Unanswered questions. Et cetera.

    So why would a layperson trust the promise of only “super tiny” chances of absolute catastrophe? It would be wiser if professionals would stress the extremely precise observations of magnetars and pulsars which have been called “the canaries in the coal mine” proving that bombardment with cosmic rays more powerful than the LHC are harmless. Google “Peskin Symmetry magazine”.

  2. Ken Bloom says:

    Hi Harry,

    I certainly accept your points — I didn’t attempt to make any real scientific case for my point, nor did I even explain what the black holes in question are. That’s because I’m no expert on the matter, and because my salary depends on the LHC (well, and my teaching; today is the first day of class here), not this blog :). I’ll see if I can recruit someone to explicate further.

  3. Colin Bembridge says:

    the same type of people that bought into “the whole atmosphere will catch fire” claims before the first H-Bomb test are the ones buying into this spurious claim.
    And “super-tiny” is more of a reference to the level of understanding of the issue that those people possess. If anyone actually thinks that this may happen, I suggest that they sell everything they own and buy lottery tickets. ;)

  4. Greg Landsberg says:

    Hi All,

    Since this whole thread was initiated by a quote from me, Ken asked me to comment on the safety issues. There are three main reasons to believe that black hole production at the LHC doesn’t pose any danger.

    First, these black holes are expected to be extremely short lived, with a typical life-time of 10^-26 seconds. Theoretically it is very hard to make a black hole stable. After all, gravity preserves time invariance, so if a black hole can be formed in the collision of two quarks, there is nothing that prevents its decay into two quarks, which is expected to be very rapid, given large available phase space for such a decay.

    Second, even if one imagines that the black hole is stable, most of them will be produced at the LHC with the velocity exceeding escape velocity of the Earth. Only one black hole out of 100,000 would actually be trapped by the gravitational field of the Earth.

    Third, even if we consider that one black hole out of 100,000 to be absolutely stable, there are very stringent limits on such a possibility. They come from the observation that ultra-high energy cosmic rays can produce black holes when they slam into neutron stars. Ina recent paper Giddings and Mangano showed that if black holes produced in such collisions were stable, all the neuron stars would have been converted into black holes by now, which is known not to be the case.

    Finally, for more on the LHC safety issues, please refer to an excellent Web page maintained by CERN:


    P.S. Gail actually misquoted me on the probability for the molecules to cross on one side of the room. It’s not 10^-25, but 2^(-10^25), which is much smaller. I guess I pronounced the number too fast.

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