“Give it what it’s worth, Doug,” said my Cockney editor one afternoon before deadline when I asked how long a newspaper article should be. Richard Rhodes takes one of the most important stories in human history — the story of the discovery of atomic structure and how that structure could be opened up, releasing vast amounts of energy — and gives it what it’s worth. The Making of the Atomic Bomb is a great work, a magnum opus, 750 pages from Rutherford’s discovery of the atomic nucleus to the horrors of the military use of atomic energy in Hiroshima and Nagasaki. Though he writes about the discovery of the fundamental forces of the universes, Rhodes never forgets or overlooks that people are doing the discovering. He captures their personalities — their backgrounds, their strengths, their sorrows, their philosophies, their styles, their foibles, and their rivalries — and sets them down on the page so that throughout the great work a reader has a clear sense of the humanity of science.
Rhodes opens the book with a chapter on Leo Szilard — “Hungarian theoretical physicist, born of Jewish heritage in Budapest” (p. 13) — one morning in London in September 1933. Within seven pages of introducing Szilard, Rhodes has sketched the milieu he grew up in, with a father who was a civil engineer and prosperous enough for the family to hire governesses who helped the children learn French and German. Upon graduating from school, Szilard won the Eötvös Prize, the Hungarian national prize in mathematics. Rhodes sets the stage for introducing later the amazing generation of Hungarian mathematicians and physicists who were Szilard’s contemporaries by noting that despite the prize, Szilard “felt that his skill in mathematical operations could not compete with that of his colleagues.” (p. 15) A brush with Spanish influenza got him sent home from his unit in the Austro-Hungarian army; he heard later that his regiment had come under severe attack in the waning days of World War I and practically wiped out. Szilard first chose engineering for his course of studies, but after moving to Berlin in the early 1920s and dabbling in chemistry, he found physics more suitable. “As soon as it became clear to Szilard that physics was his real interest, he introduced himself, with characteristic directness, to Albert Einstein.” (p. 16) Working under Max von Laue, Szilard received an obscure problem in relativity as his main task. Making no headway, he gave himself free rein to think over Christmas break. About what?
What he thought, in those three weeks, was how to solve a baffling inconsistency in thermodynamics … There are two thermodynamic theories, both highly successful at predicting heat phenomena. One, the phenomenological, is more abstract and generalized (and therefore more useful); the other, the statistical, is based on an atomic model and corresponds more closely to physical reality. In particular, the statistical theory depicts thermal equilibrium as a state of random motion of atoms. … But the more useful phenomenological theory treated thermal equilibrium as if it were static, a state of no change. That was the inconsistency.
Szilard went for long walks—Berlin would have been cold and gray, the grayness sometimes relieved by days of brilliant sunshine—’and I saw something in the middle of the walk; when I came home I wrote it down; next morning I woke up with a new idea and I went for another walk; this crystallized in my mind and in the evening I wrote it down. … Within three weeks I had produced a manuscript of something which was really quite original. But I didn’t dare to take it to von Laue, because it was not what he had asked me to do.’ (pp. 19–20)
What did Szilard do?
He took it instead to Einstein after a seminar, buttonholed him and said he would like to tell him about something he had been doing.
‘Well, what have you been doing?’ Szilard remembers Einstein asking.
Szilard reported his ‘quite original’ idea.
‘That’s impossible,’ Einstein said. ‘This is something that cannot be done.’
‘Well, yes, but I did it.’
‘How did you do it?’
Szilard began explaining. ‘Five or ten minutes’ later, he says, Einstein understood. After only a year of university physics, Szilard had worked out a rigorous mathematical proof that the random motion of thermal equilibrium could be fitted within the framework of the phenomenological theory in its original, classical form, without reference to a limiting atomic model—’and [Einstein] liked this very much.’ (p. 20)
And what happened next?
Thus emboldened, Szilard took his paper … to von Laue, who received it quizzically and took it home. ‘And next morning, early in the morning, the telephone rang. It was von Laue. He said, “Your manuscript has been accepted as your thesis for the Ph.D. degree.”‘ (p. 20)
Not content with physics, Szilard applied (alone or with Einstein, as Rhodes notes) for 29 patents between 1924 and 1934, most of them in home refrigeration. He also designed and applied for a patent in 1929 on what would later be called a cyclotron. Independently, and a few months later, Ernest O. Lawrence (working in the United States) came up with the same idea and built a working model in about a year. The device would win him the 1939 Nobel Prize in Physics.
Telling Szilard’s story as he does, Rhodes shows the interconnectedness of physics with other disciplines, the clusters of innovation that were emerging in the 1920s, the personal closeness of many of the most famous names in a rapidly changing science. Not every anecdote in this long book is as astonishing as Szilard’s dialog with Einstein, but many of them are, and Rhodes brings them vividly to life.
By 1932, nuclear physics—the study of the nucleus of the atom—was advancing as a field, and in February of that year a letter published in Nature “announced the probable existence of a neutron. … The neutron, a particle with nearly the same mass as the positively charged proton that until 1932 was the sole component of the atomic nucleus, had no electric charge, which meant it could pass through the surrounding electrical barrier and enter into the nucleus. The neutron would open up the atomic nucleus to examination. It might even be a way to force the nucleus to give up some of its enormous energy.” (pp. 23–24)
Politics, though, was closing in on physics. Hitler took the office of Chancellor in Germany in 1933, and many scientists, like Szilard, had a Jewish background. The Reichstag fire near the end of February 1933 gave Hitler an excuse to force parliament to give him emergency powers. Hitler and the Nazi party began pushing Jews out of public life immediately. Within a month, Jewish judges and lawyers in Prussia and Bavaria were dismissed. “‘I took a train from Berlin to Vienna on a certain date, close to the first of April, 1933,’ Szilard writes. ‘The train was empty. The same train the next day was overcrowded, was stopped at the frontier; the people had to get out, and everybody was interrogated by the Nazis. This just goes to show that if you want to succeed in this world you don’t have to be much cleverer than other people, you just have to be one day earlier.'” (pp. 25–26) By the end of the first week in April, another discriminatory law went into force, and thousands of Jewish scholars and scientists lost their jobs at German universities. By September, Szilard was living in London.
On September 12, Szilard recalled, he had seen headlines about neutrons and the possibility of transforming one element into another. Lord Rutherford was quoted as saying that transformation was possible, but that it would be a “poor and inefficient way of producing energy.” (p. 27)
‘This sort of set me pondering as I was walking in the streets of London [Szilard remembers] … I was pondering whether Lord Rutherford might not prove wrong.’ …
‘Consequently, neutrons need not stop until they hit a nucleus with which they may react.’
Szilard was not the first to realize that the neutron might slip past the positive electrical barrier of the nucleus; that realization had come to other physicists as well. But he was the first to imagine a mechanism whereby more energy might be released in the neutron’s bombardment of the nucleus than the neutron itself supplied.
There was an analogous process in chemistry. Polanyi had studied it. A comparatively small number of active particles—oxygen atoms, for example—admitted into a chemically unstable system, worked like leaven to elicit a chemical reaction at temperatures much lower than the temperatures that the reaction normally required. Chain reaction, the process was called. One center of chemical reactions produces thousands of product molecules. One center occasionally has an especially favorable encounter with a reactant and instead of forming only one new center, it forms two or more, each of which is capable in turn of propagating a reaction chain. …
‘As the light changed to green and I crossed the street,’ Szilard recalls, ‘it … suddenly occurred to me that if we could find an element which is split by neutrons and which would emit two neutrons when it absorbs one neutron, such an element, if assembled in sufficiently large mass, could sustain a nuclear chain reaction.
‘I didn’t see at the moment just how one would go about finding such an element, or what experiments would be needed, but the idea never left me. In certain circumstances it might be possible to set up a nuclear chain reaction, liberate energy on an industrial scale, and construct atomic bombs.’ (p. 28)
And with that, the race is on to be, not necessarily cleverer than a lot of people, but to be one day earlier.
Optional musical accompaniment to this post:
Red Car, by Trees.
Happy Petrov Day.