5 comments on “The Precipice

  1. > They were careless about evaluating whether the first nuclear explosion would ignite the atmosphere.

    Many year ago, by pure chance, I picked up a 1943 study about exactly this question, which had been recently declassified. They made a serious evaluation of this question, and concluded that there was a safety margin of about 10^7 (in ratio of energy liberated vs. energy needed to support a self-sustaining fusion reaction in the atmosphere), even assuming an igniting blast much larger than anything they knew how to create. So at least, judging from that single study, someone took it seriously enough, evaluated the risk, and found it low. Of course I have no knowledge of whether they left out something else important, did their physics or math wrong, etc.

  2. Bruce,
    Ord’s main reason for concern is the risk of model error. The group that made that study also made another estimate about nuclear ignition, specifically that lithium-7 would not ignite. The Castle Bravo test showed that was wrong, and it looks like that mistake caused at least one death.

  3. I see. How wrong was their other estimate? They’d have to be pretty wrong for a ratio they estimated as 10^-7 to be more than 1.

    (I’m not arguing any position here, since I have no knowledge about it — just curious.)

  4. The bomb produced 2.5 times the expected energy. That implies lithium-7 released about as much energy as lithium-6, whereas they expected lithium-7 to produce approximately(?) zero energy.

  5. That does sound concerning… is everything about it understood now? That is, is it understood in detail, what erroneous old model produced the old prediction, and is there a correct new model (not just experimental data) that agrees with what happened?

    BTW, that is all just a detail about one anecdote — I completely acknowledge your and Ord’s central point, which I understand to be (in part) “prediction errors occur, and people in charge of projects are heavily biased towards making them happen as opposed to being cautious in ways that might delay or stop them”. Short of altering human nature, or a political/social revolution of an unprecedented kind (which we have no evidence is possible in a good direction), is there any realistic solution? I do consider space colonization realistic (at least technically) — is that the easiest/quickest solution?

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