Notes from The Making of the Atomic Bomb

A few reflections on Richard Rhodes’s 1986 history

Did you know that drummers can read?

I read The Making of the Atomic Bomb by Richard Rhodes on tour this summer. Craig Mod called it “perhaps the most compelling, page-turning thing I’ve ever set my eyes upon,” so I bought it.

Like Craig, I think the most exhilarating part of the story is the scientific collaboration—the period before the Manhattan Project, when physicists in Europe were ping-ponging papers back and forth, egging each other on with discoveries of the structure and nature of atoms. Before death creeped in. Rhodes does such a good job of making high-level physics comprehensible. And you come to feel like you know the dozen or so key scientists involved. You root for their collaboration (and friendly competition) across borders, as each discovery directly leads to the next.

Obviously, that exhilaration is clouded by unfathomable tragedy. These are my stickiest thoughts from the first portion of the book, the academic romp.

Photograph by Masaki Oki via Patrick Witty.

It made me want to know stuff again.

My Grandpa Tweedy had a famous saying that echoes in my mind every time I put a car in reverse: “Never back up farther than you have to.”

There are a lot of ways to interpret that motto but one incorrect way is to think it means “don’t do science.” Because on its face, scientific experiment involves backing up, repeating yourself, doing work that isn’t immediately vital to getting somewhere.¹

Through no fault of my grandpa’s, I’ve become very reluctant to slow down enough to experiment. I want to learn new things and I want to solve problems well, but I also want to be “efficient.” And I don’t like risking time on unlikely guesses. So I often spend time reasoning through problems in my head rather than trying out solutions with materials.²

But as any physicist and all my favorite artists would tell you, you learn so much more, so much more quickly, when you make your ideas “real” as often and as freely as you can, even if it means dumbing it down to test it out. And it can feel fun and worthwhile. The nuclear physicists of the early twentieth century were sometimes pulling their hair out, yes, and straining their eyes counting imprints of ions, but they had a seemingly inexhaustible will to try again when techniques and hypotheses didn’t pan out.

By the way: I thought my empirical reluctance was virtuous because it requires an acceptance of not-knowing, which we valorize sometimes. But really it’s just lazy. It’s virtuous to accept that which we can’t know, not that which we can know but are too lazy to find out, lol. (It turns out that it’s easier to settle for the certitude of not knowing than it is to tolerate the uncertainty of trying to know.)

Niels Bohr is a hero.

Over and over again in the war and in the time leading up to it, Danish scientist Niels Bohr showed himself as an especially caring, independent, fearless (or at least fear-overcoming) person. When Hitler stripped Jewish scientists of their university posts, Bohr helped create an international network for escape and resettlement (and toured Germany to discreetly identify who needed help).³ Nearly all the world’s most capable nuclear physicists ended up in England or the United States because of his effort (though, at the time, he didn’t think it was possible to build atomic bombs). They would have otherwise died or been conscripted into Nazis’ own weapon project. Later in the war, when Hitler revoked Denmark’s special autonomous status, Bohr leveraged his reputation to pressure the King of Sweden to make public Sweden’s then-quiet amnesty offer for Jews and refugees of Nazi-controlled states. There were about 8,000 Jews in Denmark at the time; Bohr’s PSA campaign in Sweden saved over 7,000 of them.⁴ He was also among the first to try to help the US government understand the consequences of what it was building.

The German atomic bomb research facility was exactly as Gothic as you imagine it was.

When Allied investigators finally discovered the Nazis’ atomic bomb laboratory—not the well-equipped Kaiser Wilhelm Institute where fission and other fundamental processes were first observed, but the wartime hideaway where Nazi ordnance officials were making their last-ditch effort—they found it in a church atop a cliff (to avoid bombardment and detection), with a medieval-esque crucible in the center of it:

“In the main chamber was a concrete pit about ten feet in diameter. Within the pit hung a heavy metal shield covering the top of a thick metal cylinder. The latter contained a pot-shaped vessel, also of heavy metal, about four feet below the floor level. Atop the vessel was a metal frame. . . . [A] German prisoner . . . confirmed the fact that we had captured the Nazi uranium ‘machine’ as the Germans called it—actually an atomic [reactor] pile.” —Lieutenant Colonel Boris T. Pash

Nuclear fission is just likely enough to be discovered and just unlikely enough to not blow up planets all the time.

Let’s see if I can get this right (not only as a non-scientist but also, remember, as a drummer).

Nuclear fission, or at least one form of it, happens when a subatomic particle collides with an atom’s nucleus and bumps a neutron—another type of subatomic particle—out of that nucleus. When the neutron is bumped out, energy is released: the energy that was formerly keeping the neutron bound to the nucleus.

This process becomes a chain reaction when that neutron goes on to bump another neutron out of its nucleus, and so on. (Fission occurs in nature, but it’s usually not contained and concentrated enough to turn into a chain reaction.)

In nuclear bombs, designers have to encapsulate that fission process inside of a tamper wall so that the neutrons that are bouncing around don’t escape, and so they continue colliding with other neutrons. Otherwise, the process would just fizzle out and only a small percentage of the mass’s nuclear energy would be released.

The cores of stars are sort of like tamped bombs, creating the conditions for fission chain reactions. (Actually, their cores are so voluminous and hot that the chain reactions cross over into fusion, which is what happens when there are so many particles bumping around that pairs of two nuclei can fuse into one, which releases even more energy than one fissioning nucleus.)

Anyway, this is one of the great comforts of nuclear energy in the broadest strokes: there is basically a safety mechanism built into the nature of nuclear fission. Without tamping, a mass of material that’s chain reacting can only chain react so long before the heat of the process causes the mass to expand and spread apart from itself, thereby stopping the chain reaction (because the bumped-out neutrons can no longer reach other nuclei where they would bump out more neutrons—and they can’t bump neutrons from the atoms in ordinary air, or from just about any other element, because those elements are too stable, too much energy holds their neutrons in place). And we can only tamp so much material, for only so long, until the tamping substance is vaporized by heat. A limit on bombs. Richard Rhodes: “Untamped, a bomb core even as large as twice the critical mass would completely fission less than 1 percent of its nuclear material before it expanded enough to stop the chain reaction from proceeding.”

On the flip side of things, the naturally slow-ish speed of chain reactions (which is still sub-second fast) is what allows us to contain it within tamper at all, let alone observe them in laboratories and discover their uses—for bombs, submarine and spacecraft propulsion, plutonium pacemakers, anything.

Rhodes again: “If fission had proceeded more energetically the bombs would have slept forever in the dark beds of their ores.”

1. Grandpa Tweedy almost certainly said it to mean, The farther you back up, the more likely you are to hit a fencepost or a mailbox. When it came to science, he was a railroad punchcard programmer and a self-taught TV and radio repairman, so he was decidedly for tinkering and experimental procedure.

2. I don’t recommend having that roadblock while trying to renovate a recording studio, like I did with my friend Jason, a talented experimentalist, over the past few years.

3. Several other prominent academics also raised funds or lobbied their institutions to accept refugee scientists. The philosopher John Dewey was one of them.

4. When Bohr finally agreed to leave occupied Denmark (after learning of an imminent assassination plot), Britain flew him in the unpressurized bomb bay of a Mosquito plane. Human cargo. Bohr didn’t hear the pilot’s instruction put on his oxygen mask at altitude, so he passed out—but luckily regained consciousness when they landed, and survived.