July 16, 1945. The first nuclear device had just exploded 35 miles southeast of Socorro, N.M. It consisted of an overwhelming light illuminating the mountains all around, and a mushroom cloud rising into the bright desert sky.
Among the scientists attending the detonation, a man was standing out of a tank. He was looking at some strips of paper, measuring the distance they covered from the place where he had previously placed them. Through this simple method, he aimed to estimate the power of the explosion. This man was Enrico Fermi. Italian-born and worldwide-celebrated physicist, he had fled from Italy to save his family from the fascist racial persecutions.
He’s considered one of the fathers of the nuclear era. Along with two other Italian colleagues, he made a fundamental contribution to the development of the first nuclear devices tested at the Trinity site, and later — with much more devastating effects — on Hiroshima and Nagasaki. Much of that work took place here in New Mexico . . . in the “city that never existed” – Los Alamos.
Born in Rome in 1901, Fermi studied in Pisa, then moved back to the Italian capital city where, with a group of young physicists known as the “Via Panisperna boys” (that name coming from the road where the Institute of Physics was then located), in 1934 he made new fundamental discoveries on neutrons — and later, on the basics of the atomic bomb. In 1929 he was appointed a member of the Royal Academy of Italy by Benito Mussolini, and joined the Fascist Party.
During the 1930s Fermi gradually became interested and involved in American scientific research, as the United States provided a more stimulating and better-financed workplace. Later, he was deeply struck by the 1938 Racial Laws passed by the Fascist government against Jews stemming, no doubt, from the fact that his wife, Laura Capon, came from a Hebrew family. So, when he was awarded the Nobel Prize in 1938 and was invited to Stockholm, he and Laura didn’t return to Italy but rather settled in the United States.
It was here, shortly after the war broke out, that his genius became widely recognized by the U.S. government and by other physicists working on ‘The Bomb.” Robert Oppenheimer himself, the head of the Manhattan Project, called upon Fermi to join the secret labs in Los Alamos (at that time known as “Site-Y”).
Fermi was at that time perhaps the most important expert in controlled nuclear reactions. At the University of Chicago in 1942 he, and his team finally succeeded in creating an atomic pile — the first working nuclear reactor. The so-called “Chicago Pile” (CP-1) signified a milestone in the use of nuclear energy. Some of Fermi’s original instrumentation is now displayed in the Albuquerque’s National Museum of Nuclear Science and History. Through original materials, models and videos, the display traces the path from the early nuclear experiments all the way to the Manhattan Project and the Cold War.
Finally persuaded in September 1944, Fermi arrived in Los Alamos and was appointed head of the F-section (named after him) whose task was the development of nuclear fission and the likely development of a thermonuclear H-bomb.
“For his broad knowledge he was frequently asked by the other scientists and considered a sort of general consultant, and soon throughout the labs he became known as ‘The Pope,'” explains Dr. Roger Meade, professor of history at Arizona State University, during and interview in Los Alamos.
Emilio Segré, Nobel Prize recipient and Fermi’s friend and colleague, also reminded during an interview for the Italian broadcast that “when there was some mess, they always called Enrico.”
Today, a partial reconstruction of those months and a thorough review of the nuclear era can be found in Los Alamos at the Bradbury Science Museum. The display, consisting of photographs, letters and videos, examines Fermi’s and other scientists’ lives in that remote plateau, spurred by the incumbent fear that German scientists would achieve the atomic bomb first.
In July 1945 Fermi was among those at Trinity who observed directly the first nuclear explosion. From his paper strips experiment he determined that the power of the explosion was around 10 kilotons (or 10,000 tons of TNT). In actuality, the Trinity “Gadget” had a power of about 18 kilotons. After that test, some of Fermi’s colleagues (e.g. Leó Szilárd) asked President Harry Truman not to use the bomb on civilians, preferring instead a demonstrative test in the face of Japanese ambassadors. Fermi, however, never signed those petitions.
“He always had the neutral approach of the researcher,” Meade said . Although before the war, he had warned the U.S. government about the use of nuclear weapons and had always intended the “pile” as a research instrument for civilian purposes, Meade added.
Fermi wasn’t the only Italian physicist who worked in Los Alamos. Two other prominent personalities took part in the construction of “The Bomb.” The first was Emilio Segré, one of the “Via Panisperna boys.” He was of Jewish origin and therefore a target of the fascist Racial Laws.
He settled in California, and in 1943 was asked by Oppenheimer to join the Project because of his research on radioactivity. Segré headed up the P-5 group and, with his team, studied fission products and their radioactivity, as well as the effects of the Trinity test.
The “Gadget” used at Trinity was actually an implosion-design plutonium device based on the work of Segré and his team. The Nagasaki bomb “Fat Man” operated on the same principle whereby a core of plutonium is pressed by the detonation of a traditional explosive siding, thus producing a nuclear reaction, energy and power. Segré received the Nobel Prize in 1959, along with Owen Chamberlain, for the discovery of the anti-proton.
A third Italian at Los Alamos was Bruno Rossi, also of Jewish origin, and considered one of the greatest experts in cosmic radiations and astronomic research. Rossi was invited to New Mexico by Enrico Fermi himself, but was deeply hesitant as he hoped “The Bomb” wouldn’t be used on civilians. In post-war years he became increasingly opposed to nuclear proliferation and firmly criticized President Ronald Reagan’s Space Shield project.
“After the war, only Fermi continued at Los Alamos laboratories as a consultant, making his contribution to later nuclear research,” said Meade. In 1956, the United States Atomic Energy Commission named its highest honor after Fermi. Renowned scientists and Fermi’s colleagues in “Site-Y” like Otto Hahn, Robert Oppenheimer, Edward Teller and Hans Bethe, all received the Fermi Award. In recognition of his prudence in complex theories and his inclination towards quick and simple solutions, back-of-the-envelope calculations became known as the “Fermi method.”