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Breathe easy, the LHC still won’t swallow the Earth

The CMS experiment

By James Dacey

“Of the billions who tuned in for the switch-on, I suspect that many were only interested in seeing whether or not we would be blown to smithereens.”

The words there are those of John Ellis, a senior research scientist at CERN, talking just now at the AAAS conference in San Diego about why the Large Hadron Collider (LHC) was never really going to destroy the planet.

I was half expecting (rather, hoping) that the talk would be gate-crashed by a gang of doomsday mongers; or perhaps even Walter Wagner, the high-school physics teacher who filed a federal lawsuit in the US District Court in Honolulu in 2008 to prevent the LHC from starting up.

Alas, they all failed to show.

Ellis, who has worked on several LHC experiments, gave an eloquent description of how CERN responded to all the scaremongering. It was the usual stuff, but it was interesting to here of how Ellis’ colleagues had taken “months” out of their research to calculate the exact nature of the tiny black holes – the ones that almost certainly wouldn’t be produced, and even if they were, would possess the “energy of a fly”.

If you’ve never really trusted those CERN guys, or you’re just really bored, you can find extensive details of all the LHC’s safety precautions here.

Despite his sensible words, I’ve got to say I was a bit surprised by Ellis’ reply to my question over whether physicists, when talking with the media, should stop discussing doomsday scenarios in terms of statistics and just say “no – there is no chance”. “I’m a scientist,” he said. “We deal in probabilities.”

Ellis was speaking as part of a larger discussion entitled Organizer: Doomsday Versus Discovery, in which other speakers discussed how the media have reacted to the developments at CERN and the historical and philosophical issues surrounding the fear of big science.

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  1. Why be surprised?
    If the probability of an event is so small, but never zero according to quantum mechanics, that a person should wait billions of years for it to happen, three possibilities exist:
    1) Either the person worried suffers from illusions of immortality, or
    2) The person worried has to readjust priorities in life, or
    3) The person worried has not considered more amusing and relaxing events that have much greater probability of happening.

  2. Dear George Triantaphyllou, you repeat a misleading argument: The probability of disaster at LHC is not as small as anything else theoretically possible in some ideas of quantum mechanics, like the one of a pencil falling “up” instead of down because of an accidental, spontaneous new arrangement of the matter involved.
    By the way, I don’t believe in such ideas at all presently. But if I would, it would still be ridiculous that scientists, journalists and bloggers still repeat this as a safety argument in favour of the big bang machine. One is for sure: It is not as likely that a severe accident occurs in an experiment with ant populations or anywhere else on the planet as it is in high energy experiments of this dimensions.
    Another misleading argument, mosquito comparison, recently repeated by AFP: “Before the LHC experiment, no particle accelerator had exceeded 0.98 TeV. One TeV is the equivalent to the energy of motion achieved by a flying mosquito.”
    In the LHC the energy is compresses to a millionth of a millionth of the volume of a mosquito. That’s why it will get much hotter than in the interior of the Sun. The LHC running at full energy would be equivalent to the power of an aircraft carrier – concentrated in a beam thinner than a hair. Is it the task of a news agency to report only about what it receives from CERN?
    Well it could: Here is a CERN scientist’s calculation: One beam could hit a 30 meter deep hole in a solid block of copper. This would be more appropriate as a comparison to illustrate what’s going on than a “mosquito race”, as if it was a natural event.
    Let’s have a third misleading argument: You might have heard that one already: “If you do the arithmetic, you’ll find that you’d have to run the LHC for 100,000 years in order to have the same collisions that the universe has brought to Earth already.” This sounds assuring. But the same figures show: 10 years LHC collisions are equivalent to 400.000 years of cosmic ray collisions on the whole earth.
    (Other figures roughly mentioned result in 1 magnitude less – and point into the same direction.)
    Then, presently we don’t know the sort, mass, velocity and origin of high energetic cosmic rays. Their energy is taken from indirect measurements. So if the comparison between cosmic ray collisions and LHC collisions is not right in any principle way – which is still in question – not even the figures above would be adequate.

  3. Jimbo

    The paranoia persists for one cinematic reason:
    and one literary reason: `The Genesis Machine’, James P.Hogan.
    `The Void’, was a 2001 scifi movie depicting a black hole generating accelerator. Despite being a box office flop, the word spread, not just of Amanda’s nipples, but of what could happen if black holes materialized out of an accelerator.
    So EVERYONE hopped on the bandwagon, and the result is today’s nuttiness about the LHC.
    Just like the conservatives do, blame it on Hollywood primarily. Much more intelligently done, but less well known, was Hogan’s 1979 hard scifi novel, in which black holes were used as a defense technology to stop war altogether.

  4. Dear LHC-Kritik,
    I did not mention any of the arguments you list, because they refer to different physical processes that can hardly be compared with the ones taking place at the LHC.
    My argument was based on pure probability theory. The probability of a disaster is so small that one should not worry for purely practical reasons. If one kept worrying for all possible, however improbable, eventualities in life, one would be immobilized in inaction. One would never use electricity, never travel, never make children, never strive for personal and social advancement. It would be too risky.
    The unfairness surrounding the discussion of LHC dangers is at least twofold:
    1) It is based on scientific calculations, the results of which are then used by non-specialists against science and rationalism itself.
    2) It uses a high-profile scientific endeavour to gain in importance, while other human activities like travelling, electricity, construction, nutrition, health care etc. hide dangers of a probability several orders of magnitude larger.


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