The Making of the Atomic Bomb

Reading Challenge Book 6 – A Pulitzer-Prize winning book

The Making of the Atomic Bomb, by Richard Rhodes

Amazon link here

I didn’t actually realise this was a Pulitzer-Prize winner when I started reading it, so the revelation was pretty convenient for my reading challenge. After reading Hiroshima and Gods of Metal, I was looking for a history of the development of the atomic bomb. TMotAB more than fulfilled this brief! It is quite extraordinary.

TMotAB explores the history of atomic physics from the beginning of the twentieth century, through the discovery of the electron, the postulated ‘plum-pudding’ model, the discovery of the neutron, to the realisation that uranium was capable of sustaining a nuclear chain reaction. This history provides a huge amount of detail about each scientist who was involved, their family and educational background, something of the circumstances supporting their significant work, and detail of the hypothesis/discovery itself.

Once this discovery was made it outlines the challenges that scientists faced in bringing their discovery to the attention of the US government and in getting its support (and funding) for the Manhattan Project, then the practical challenges – engineering and chemical of developing the atomic bomb, or specifically, of manufacturing and isolating sufficient weapons-grade atomic material.

But TMotAB is not just a science book. It also considers the history of the use of weapons from WWI onwards, and the gradual shift of opinion that has led to a concept of ‘collateral damage’.

That’s a lot of material, and I think it took me three weeks to read this book. The science was hard – I found myself dipping into Wikipedia to clarify concepts – and I haven’t maintained a firm grasp of the history in my mind. I see myself re-reading this book at some point in the not-so-distant future, to try and embed some of what I’ve read.

What were my key take-aways? 

Fallout is scary, but nuclear winter is scarier

A study in 2008 investigated the likely result of a theoretical regional nuclear war between India and Pakistan, involving only 100 Hiroshima-scale nuclear weapons (conservative). They considered it likely that such an exchange would be targeted on cities which by nature happen to be filled with combustible materials. This would lead to firestorms which would inject massive volumes of black smoke into the upper atmosphere, spreading around the world and cooling the earth for long enough to lead to worldwide agricultural collapse. The death toll from the initial strikes would maybe be 20m, but the agricultural crash leading from the earth’s cooling would be much, more severe (the study mentions deaths of a billion).

One of the authors of the study gives a TED talk about it here. I don’t necessarily agree with all of his analysis, but the central portion discusses the information I’ve recapped here in more detail.

Bohr was a wise old bird, and the Cold War was inevitable

As the Manhattan Project progressed, one of the key decisions that the USA had to make was when to inform the USSR about their nuclear development program. The UK already knew about the program, having shared its early research with the US and strongly encouraged it to pursue development. The Soviet Union… not so much.

Relations between the USA and USSR were strained. Towards the end of the war, the extent of the USSR’s ambitions in Eastern Europe, particularly its plans for Poland, became apparent. The USSR was assessed by Truman’s advisers as being the only nation which had the technological and financial capabilities of developing nuclear weapons. As these and other tensions grew, the USA hoped that it could conclude its war in the Pacific without the USSR’s involvement, so that post-war, it would be supreme in the Pacific sphere. The USA feared that if Stalin knew about the atomic bomb, the Soviet Union would accelerate its timetable for involvement in the Pacific, increasing its post-war influence there.

Arguably, the US government took a short-term, WW2-centric view when determining its use and disclosure of the atomic bomb. However, certain scientists involved in the Manhattan Project, such as Leo Szilard and Niels Bohr, were already considering the wider picture and the longer-term consequences of the government’s decisions.

Imagine a world where America built the atomic bomb, but then instead of deployment, shared the knowledge of its existence and capabilities with the rest of the world . Imagine that other world leaders were able to think beyond the instinctive reaction of ‘These new weapons will make me all-powerful’, and realise that a world where everyone has nuclear weapons is less secure than a world where no one has them. Imagine that all countries banned the development of nuclear weapons, and that their munitions research was made sufficiently transparent that no country could develop its own nuclear weapons without discovery. Imagine that this scientific transparency led to wider, social transparency, where social conditions in every country were open for judgement and comparison, exposing the inequality in the world and alleviating it.

This was Bohr’s vision. It was clear to him that if the USA delayed informing the Soviet Union of its development of nuclear weapons for long enough, this would lead to serious distrust between the Allies, which would increase the risk of a nuclear arms race. He shared his concerns and suggestions with Churchill, FDR and then Truman.

But ultimately the USA put its national interests first, and the Soviet Union independently found out about the Manhattan Project following reports of the Trinity testing in July 1945. And it turned out that hiding massive military secrets from a paranoid dictator didn’t build the level of trust necessary to support a long-term truce.

Bohr’s vision was idyllic. It was also misunderstood by others and then misrepresented to the key stakeholders in the US government. It never had a chance.

 

The people

The history of nuclear science wasn’t just told through discoveries but also through the personalities of the players, and this helped bring this history to light. Previously I hadn’t realised how many Jewish scientists were in the European scientific sphere pre-WW2. During the war Born and a number of other scientists worked tirelessly to help find positions for Jewish scientists within non-occupied countries (Britain took on the largest number of scientists).

This paints a picture of how Europe’s science program lost out and how America and other countries benefited – for example, one hundred refugee physicists emigrated to the US between 1933 and 1941. Other up and coming scientists potentially had their careers destroyed. After Bohr left Denmark, Einstein wrote to him saying, “I am glad that you have resigned your positions. Thank God there is no risk involved for either of you. But my heart aches at the thought of the young ones.” It’s probably silly to be moved by this when so many people in Europe died, but it’s just one (small) illustration of the upheaval to people’s lives.

Thank God for computers

Reading about the Manhatten Project inspires me with a sense of awe similar to reading about the work at Bletchley Park, or the development of the US’s space programme. The intense, coordinated effort of so many people to innovate and achieve the seemingly unachievable astounds me. Especially as they did it all with slide rules.

Okay, that’s blatantly not true for the space programme, but the technology we depend on every day just didn’t exist. If you look at the achievements made, where basic technology was shored up with pure genius, it’s frankly a bit bonkers.

Physics + Chemistry = OTP

The history gave me a better understanding of the relationship between physicists and chemists in the discovery of fission. Discoveries were two-directional: chemists designed experiments to attempt to verify physicists’ theories, and physicists used unexpected experimental results to develop their theories of the atom. I hadn’t previously appreciated that uranium is the largest naturally-occurring element (thereby a good candidate for sustainable fission).

Interestingly, some scientists (e.g. Leo Szilard) predicted the possibility of sustainable nuclear fission very early on in the history of nuclear discoveries, but were unable to identify any elements where it occurred through experiment alone. Other scientists discovered fission through experiment but didn’t realise the implications of their experiments.

Chemistry is hard

I don’t think I had any sense of what chemistry was like outside of school, and how hard it could be, until I read this book. A good example is the difficulties that scientists experienced when trying to identify the by-products of the fission of uranium.

By bombarding uranium with neutrons, scientists were able to initiate and detect beta decay. This suggested to them that the product of this reaction might be an element with a higher atomic number than uranium (i.e. the as-of-yet undiscovered plutonium). Chemists then tried to prove this experimentally.

Fermi performed his own research into this, using his knowledge that the fission product was a beta-emitter. His first step was to take his sample (i.e. the original uranium compound plus its fission products) and dissolved them in nitric acid so that they would be in solution. Then, in a series of experiments, he added another chemical (known as a carrier) to the solution, to initiate a chemical reaction and create a precipitate that could be separated from the solution. He finally tested the precipitate for radiation. Given that the fission product was a beta-emitter but the uranium compound was not, he knew deduce that if the precipitate were also a beta-emitter, the fission product had been separated from the uranium solution by the chemical reaction and precipitation.

By performing this experiment with a number of different chemicals, and using his knowledge of the reactions of these chemicals with elements in the periodic table and their related compounds, Fermi was able to prove by exclusion that the fission product was not uranium, protactinium, actinium, etc. Not what it actually was. That’s ridiculously hard work, especially given the time-pressure caused by the fission product’s half-life of only 13 minutes.

Everything I’ve just described is trivial compared to the process for separating plutonium from irradiated uranium.

Separating isotopes is harder

So separating chemicals is hard. What about separating isotopes? Think about U235 and U239 – they have extraordinarily similar chemical properties, and their mass is less than 2% different. Scientists were able to propose three key methods of separation, which relied on this mass difference, but as the difference was so small the methods had to be used iteratively – repeated over and over again – to achieve any level of enrichment.

Who would I recommend TMotAB to?

To read this book, you would have to have a genuine interest in the history of nuclear physics, otherwise it’s just too dense. Similarly, if you’re the kind of person who describes yourself as ‘Oh, I was always terrible at maths,’ I suspect this might not be the book for you – not because there’s any hard maths involved, but because I suspect most people wouldn’t find the science interesting if they’re not at all maths-inclined. Lastly, there is a definite time-investment to reading TMotAB – I wouldn’t pick it up if work, or anything similar, is taking up all your time.

 

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