But are the unknowns as bad as Crichton suggests? Almost certainly not. The very first value is "number of warheads". This number can certainly be estimated... There are probably people in the U.S. whose entire job is estimating this number. The numbers given in non-proliferation treaties are likely not more than an order of magnitude off. Likewise, we can probably estimate the "size of warhead" and "height of detonation". I don't know how well the others can be estimated; they appear to be physically based, so perhaps small-scale experimentation would yield reasonable values and probabilities.

But Crichton insists none of these numbers can be known at all -- that how much smoke a city gives off when it burns is every bit as unknowable as the probability that a planet will generate intelligent life. I think he may be exaggerating a little.