Review of The Pope of Physics by Gino Segre and Bettina Hoerlin

The Pope of Physics: Enrico Fermi and the Birth of the Atomic Age

by Gino Segre and Bettina Hoerlin

(Henry Holt, 368 pages, $30, October 18, 2016)

Reviewed by Dr. Fred Bortz
Dr. Fred Bortz

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Authors looking to mine science history can find no richer lode than physics in the early- to mid-twentieth century. New subatomic discoveries and the ground-breaking theories of relativity and quantum mechanics challenged and reshaped scientific understanding about the nature of matter and energy, space and time.

Then in 1938, while the world was being shaken by the rise of Fascism in Europe–most notably Adolf Hitler in Germany and Benito Mussolini in Italy–came the momentous discovery of nuclear fission and the rapid realization that the phenomenon could be used to build a bomb with previously unimaginable destructive power.

Stories of the science and technology of that period have produced a vast body of literature. But to a biographer’s delight, behind those discoveries is a rich cast of characters. One of the most important yet not fully appreciated of those is Enrico Fermi (1901-1954), whose near infallibility in both the theoretical and experimental realms led his Italian colleagues to give him the nickname The Pope of Physics–the title of a new biography by University of Pennsylvania physics professor Gino Segre and his wife, former Philadelphia health commissioner Bettina Hoerlin.

Few writers are better positioned than that duo to bring Fermi’s story to light. Segre is the nephew of Nobel Laureate Emilio Segre, Fermi’s first graduate student and long-term collaborator.

Hoerlin, the daughter of a physicist who fled Europe to escape the rising tide of European anti-Semitism, grew up in the Atomic City of Los Alamos, NM, where Fermi was one of the key scientists developing the atomic bomb. The Segre family was part of the same wave of refugees, as were Fermi and his Jewish wife, Laura. Combining family lore with intensive research, Segre and Hoerlin offer unique insights into Fermi’s life and work, set against the background of politics and the early years of the Atomic Age.

Readers first meet the young Fermi as an exceptional student whose intuitive grasp of physics quickly leaves his professors far behind. At that time, Italy was a backwater in physics, but Fermi’s appointment to a professorship soon changes the dynamic. He assembles a group of students and colleagues who became known as The Boys of Villa Panisperna for their relative youth and adventurous spirits as well as their scientific prowess.

Fermi’s first major accomplishment was theoretical. In the type of radioactivity known as beta decay, a nucleus emits an an electron that does not carry off as much energy as physicists initially expected. Fermi postulated that a previously unknown subatomic particle that he named the neutrino (“little neutral one” in Italian) accounts for the rest. Because the neutrino was undetectable at the time, the theory met with considerable resistance. However, it fit so well with experimental results that physicists soon accepted it.

His next triumph was experimental: the generation of beams of “slow” neutrons that were able to penetrate into the nuclei of a target material and create new radioactive isotopes. This work proved to have great scientific and technological value and led to Fermi’s 1938 Nobel Prize.

Largely apolitical, Fermi was acceptable to Mussolini as one of first thirty distinguished appointees to the Royal Italian Academy in 1929. For nine years, he was able to ignore the rising tide of Fascist ideology. But in July 1938, as Mussolini launched an anti-Semitic campaign, Fermi began to lay the groundwork for his family’s escape to the U.S. When he and Laura left for Stockholm to accept the Nobel Prize in December, they knew that they would not return to their beloved homeland for many years.

In the U.S. at Columbia University and the University of Chicago, Fermi quickly emerged as a leader in nuclear fission. After achieving a chain reaction, he was a central figure in developing an atomic bomb.

Biographies of physicists tend to focus on personal quirks. With the down-to-Earth Fermi, that is not possible, though the prologue opens the book with a memorable anecdote from the Trinity test that ignited the Atomic Age.

Immediately after the blast, Fermi “began tearing a sheet of paper into small pieces and then dropping them from his upraised hand…. [A]s the front of the shock wave hit, the midair pieces were blown a short distance away. He paced off the distance to their landing points and soon had an estimate of the blast’s force. The number from his simple test was remarkably close to the magnitude determined by detailed measurements a week later.

“None of the physicists was surprised,” the authors note. The Pope of Physics was right as usual.

Fred Bortz is the author of the twentieth-century history Physics: Decade by Decade (Facts On File, 2007).