22 December 2015

Manhattan-ish projects

So today I saw yet another of these stories where “Politician X calls for a new Manhattan Project to Do Some Impossible Thing”.

I don't want to pick on this particular politician right now (though I am mightily disappointed), I want to talk about learning the wrong lesson from the Manhattan Project.

Many people seem to think that the Manhattan Project shows that you can just order up any breakthrough you want and if you give enough scientists enough money, they will just cook it up for us. “Here's a trillion dollars, go invent an antigravity machine.”

That's not how it works.

FDR did not wake up one morning and say, “Hey, wouldn't it be great if we had a bomb that could blow up a whole city? Let's get our scientists working on that.”

No, it was a thing physicists thought of, not politicians or generals. Grad students had been standing at chalkboards through the late 1930s working out the cross-sections of uranium nuclei, and the difference in mass between uranium nuclei and their fission products, and saying, “Huh, it ought to be possible to make a mind-bogglingly powerful bomb”, half-joking and half-horrified. “Boy, it's a good thing that to really build something like that you'd have to deal with a bunch of weird engineering problems that would be hugely expensive to solve,” they would say, nervously.

Then after a few years of that the US was at war with Nazi Germany. American universities, as a result, were hosting an awful lot of German Jewish physicists who had emigrated because they saw the writing on the wall. Physicists got to talking. Who was the one person in the world who was best-qualified to crack the problem of making a fission bomb not at a blackboard bull session but in real life? Werner Heisenberg, obviously. And where was he? Still in Germany. What was he working on these days? Nobody knew for sure.

Other pieces were falling into place, too. Better and better understanding of chain reactions. Better and better techniques for handling uranium.


So some physicists got together and wrote a letter to the President of the United States explaining the potential for fission bombs. They got the most famous and respected scientist in the world, a German Jew named Albert Einstein, to sign it. And that led, ultimately, to the Manhattan Project and the Bomb.

The Bomb is so stunning and counterintuitive and such a dramatic demonstration of the power of technology to bend the Cosmos to our will — and the Manhattan Project such a dramatic example of a big, expensive, resource-intensive project bearing fruit that changes the world — that it creates the impression that anything is possible. But that is the wrong lesson.

Remember: the scientists came to the politicians with the proposal. Not the other way around. Because the Cosmos does not coöperate with what we want, and scientists are not short-order cooks.