The Last Man Who Knew Everything

by David N. Schwartz

  Oddly enough, given what he told Amidei regarding his desire to study only physics, he started off as a mathematics student, perhaps reflecting the Scuola Normale’s worldwide reputation for its mathematics faculty. Faculty members had written many of the textbooks Amidei had provided during Fermi’s informal studies in Rome. The mathematicians of the Scuola Normale were not merely textbook writers, they were at the cutting edge of the field and quite powerful at the school, a fact that could not be said for the physicists either at the Scuola Normale or at the university. This may account for Fermi’s decision to enroll in the mathematics degree program. Within a year, however, he had shifted his formal focus to physics, taking courses at the university under the guidance of Puccianti, who soon realized that the best way to educate the young prodigy in physics was to let him loose in the university library.

  Fermi attended lectures and seminars, both at the Scuola Normale and at the university, but in letters to Persico, he indicated that the lectures took relatively little time and effort and he spent much of his time in independent study. The Scuola Normale expected its science students to take a full load of physics, mathematics, and chemistry. Fermi earned perfect grades across the board. He took courses in German and received perfect grades in that subject, too. At the university, his transcript shows perfect performance in every science course, with honors in most. The one course in which he did not receive a perfect grade was in Freehand Drawing (Disegno a mano libera), in which he received a “24” out of “30.” He had covered almost all of the required material in mathematics and physics during his time with Amidei, so the class work was simple and he had plenty of free time to spend in the library, keeping up with research articles on quantum physics and relativity in the major physics journals. Enrico’s letters to Persico suggest that the only courses that involved some work for him were those in chemistry—not surprising, because he had not studied chemistry with Amidei and had little interest in the subject.

  THE ENTERING CLASS AT THE SCUOLA NORMALE IN 1918 WAS UNUSUAL, the bulk of the class having been admitted in 1915 but only now arriving in Pisa with the war’s end. The Scuola Normale had long been a training ground for Italy’s intellectual and cultural elite, and Fermi’s class was to prove no exception. Among his classmates were individuals destined for great achievement in mathematics, astronomy, and physics. One of those he quickly befriended was a young man named Nello Carrara, who had arrived a year earlier. Skinny and athletic, he and Fermi became fast friends.

  There was, however, another student, not at the Scuola Normale but enrolled as a physics student at the university, with whom Fermi would develop a legendary, lengthy professional and personal relationship. His name was Franco Rasetti.

  Born in a small village in Umbria near the town of Castiglione del Lago, Rasetti was about six weeks older than Fermi, but in appearance he could not have been more different. Tall and beanpole thin, with a scrawny neck and bony face, he gave the impression of a human ostrich. He was close to his mother, and when Rasetti was admitted to university the whole family moved to Pisa, where they lived together in an apartment in town.

  Rasetti was a true eccentric. He initially chose physics as a subject for university study because, he later explained, it was not a science that involved memorization and classification and would thus be a challenge for him. But in fact he had an extraordinary memory and focused it on classification projects in marine biology and botany; he was able to identify thousands of different species of mollusks and flowers. In later years he would turn from physics to biology as his primary field of study.

  Rasetti met Fermi in science classes at the university, and the two immediately hit it off. Fermi became a frequent visitor to the Rasetti household and often dined with them despite the fact that normalisti received free room and board. The young men shared an impish sense of humor and soon formed an “Anti-Neighbor Society” dedicated primarily to irritating members of the public with pranks and public displays of disrespect. One of their favorite pastimes was tossing bits of sodium into Pisa’s public urinals, enjoying the reaction of those at the urinals when the sodium exploded upon contact with water. They would walk up to strangers and put padlocks through buttonholes on their jackets, locking the jackets closed. Fermi even played this prank on Rasetti, padlocking the front door of the Rasetti household closed while the family was inside. They loved to place a pan of water atop a door that was slightly ajar and watch as an unsuspecting victim brought the pan down on himself. They fought mock sword fights on the rooftops of Pisa. They concocted a stink bomb and exploded it in a classroom during a lecture, for which they were almost expelled. They were saved only through the intervention of Professor Puccianti, who prevailed on them to limit pranks to those who would not get them into further trouble with university authorities.

  When they were not wreaking havoc in town, they were hiking in the mountains north of Pisa, often joined by Nello Carrara. The three of them loved strenuous physical activity and spent most free weekends, weather permitting, hiking in the Apuan Alps north of the town, home to the famous Carrara marble quarries. For Fermi this was the beginning of a love affair with mountain hiking, an activity he pursued to the end of his life. The Anti-Neighbor Society eventually grew into a larger circle of friends, both male and female, with slightly more congenial ambitions. The members would spend weekends exploring the hills and mountains above Pisa, Fermi typically out in front, charting the path for the day’s walk, leading the way, and determining when they would return. He was the group’s natural leader, and in a pattern that was to be repeated throughout his life, people around him were happy to follow wherever he decided to go.

  Fermi’s exposure to the opposite sex was not limited to weekend jaunts with the Anti-Neighbor Society. Both the Scuola Normale and the university admitted women. In a letter he wrote to Persico, Fermi revealed a distinctly unattractive attitude toward his fellow female students, composing a cruel skit in which he ridiculed them—“barring one or two exceptions ugly enough to scare anybody”—by portraying them as incapable of reducing a simple fraction. Yet he must have been attractive to women. They enjoyed hiking with him and found him intellectually impressive and self-confident. They might well have also found him to be slightly immature. The combination of Fermi and Rasetti, with their constant teasing and posturing, would have been enough to try anyone’s patience, as it clearly did with young Laura Capon a few years later. Fermi’s eagerness to ridicule the intellectual abilities of the women around him would not have been particularly unusual in his day, or decades later, for that matter. Perhaps it reflected merely the widely shared prejudices of his time and culture. More than likely, it was also a bravado with which he could mask his awkwardness around women, an ineptness he would eventually outgrow.

  FIGURE 2.1. Fermi, Rasetti, Carrara in the Apuan Alps north of Pisa. Courtesy of Amaldi Archives, Department of Physics, University of Rome, La Sapienza.

  AT THE UNIVERSITY, FERMI AND RASETTI TOOK MANY COURSES together. One such course was analytical chemistry. In one memorable lab session, they were asked to identify the components of a chemical mixture using the analytical chemistry techniques they were supposed to master. Looking at the mixture, Fermi decided that it would be easier and more straightforward to examine it under a microscope and visually identify the components. They scored a perfect grade for the lab. No one was the wiser.

  University life was not all fun and games. Fermi was a serious, passionate student of physics and his independent reading stayed with him throughout his working life. He mastered Poincaré’s classic work on the hydrodynamics of whirlpools and absorbed two other classic books, Appel’s Mechanics and Planck’s Thermodynamics, so well that he could recall proofs from them years later. His knowledge of relativity and quantum theory was soon greater than that of his teachers, and he frequently gave lectures on relativity. Puccianti, a generous, very old-fashioned physicist, would ask Fermi to lecture him on theoretical subjects that puzzled the older man.
In these sessions Fermi honed his pedagogical skills, skills that would play a central role in his subsequent career. Puccianti appreciated these mini-seminars so much that he eventually dubbed the younger scientist his very own expert on relativity.

  Fermi spent the summer of 1919 between his home in Rome and his grandfather’s home just outside Piacenza and began a process that would continue throughout his life and distinguish him from virtually every other physicist of his generation. He dutifully recorded the entire sum of his knowledge of physics in a carefully organized notebook, written in miniscule handwriting. Subsequent notebooks—twenty-five of which are in the Fermi archives at Pisa’s Domus Galilaeana and several dozen more in the archives at the University of Chicago—reflect the astonishing, continuous intensity of his physics activities. He was, in a real sense, the Voltaire of physics, always scribbling away in his notebooks, solving problems.

  The 1919 notebook is 102 pages long and contains a wide range of material on advanced physics. One senses that this notebook, and all subsequent ones, served as his way of internalizing a deep foundational knowledge of physics that he carried with him for the rest of his life. Given his appreciation for his own abilities, he may even have written the notebook with a view toward future historians interested in how he learned his discipline.

  It soon became apparent to those around him, students and faculty alike, that they were in the presence of a rare mind. As would happen often during the Manhattan Project some two decades later, professors would call him to solve equations that proved resistant to straightforward solution. In response, he would work his way steadily to the solution the professor had been struggling toward. He also developed some of the personal tics that would stay with him. When lost in thought he would grab some nearby object—chalk, pencil, or, in one case, a pen knife—and fiddle with it absently. With the pen knife, he tapped it in the open position against his forehead near his right temple and sliced himself by accident, leaving a small scar that he carried for the rest of his days.

  After his second year in Pisa, he was allowed to focus full time on a university physics program that lasted another two years. Rasetti and Nello Carrara were admitted to the program with him, and Puccianti gave them free rein over the department’s laboratory facilities, primitive though they were. Experimental physics was, as Rasetti later explained, the only subject in which one could receive a degree. Theoretical physics was not considered a separate, legitimate academic field. Puccianti’s labs were, unfortunately, poorly set up for advanced experimental work. Much of the apparatus in the lab was fit only for demonstrations during lectures. The three students spent a few weeks exploring the equipment they found in cabinets and drawers, and Fermi decided—for all three of them, apparently—that the most promising research lay in the direction of X-ray research. They soon discovered that the X-ray tubes at their disposal were not suitable for the kind of experiments they wanted to do, so they built their own, with the help of a local glassblower.

  In later years, Rasetti noted that Fermi’s disinterest in any distinction between theory and experiment was evident even this early. Fermi was “from the first a complete physicist.” The temperaments of theorists and experimentalists are often thought to be quite different, the former more comfortable in an isolated setting solving theoretical problems, and the latter, more collaborative, enjoying the design and execution of experimental projects. From an early age Fermi effectively and eagerly bridged this gap. He combined a willingness to noodle on a theoretical problem for a sustained period with an enjoyment of working with his hands on an experimental design. Perhaps this was because the Italian physics establishment did not take theory particularly seriously and encouraged this gifted theorist early on to get his hands dirty in the lab. Perhaps if theory had been held in higher regard in the corridors of the University of Pisa, he would not have developed into the balanced physicist he became. However, it is clear from his childhood efforts with Giulio and later with Persico that he loved to tinker with objects, to make machines, to do physical experiments. Naturally gifted in both, he saw no need to choose between them. Fermi saw physics as an integrated whole. By the time he was ready to present his experimental dissertation to the examiners at the university, Fermi had already published several theoretical papers in scholarly journals.

  His first was a paper on electrodynamics of a rigid, charged body. The second and third papers focused on his first love, relativity theory; the third presented an important theorem about how the theory works within very small distances and proposed a system of coordinates to make the analysis of these small distances easier to compute. The fourth was a highly successful effort to reconcile the different ways that the electromagnetic mass of a rigid spherical charged body—that is, the mass measured by application of force in an electromagnetic field—is measured in classical electrodynamic theory and in relativity.

  A fifth paper, apparently commissioned for a German publication while he was still at Pisa but published after graduation, was an appreciation of relativity. This essay was one of the very few published by an Italian physicist to evince any enthusiasm for Einstein and his outlandish theories of space, time, and gravity. Fermi’s main purpose was, characteristically, to call attention not to the puzzling philosophical and metaphysical consequences of the theory but rather to one of the theory’s most compelling physical predictions:

  If we could liberate the energy contained in one gram of matter we would get more energy than exerted by a thousand horses working continuously over three years. (Comments seem superfluous!) It will be said, with good reason, that in the near future at least that it does not appear possible to find a way to liberate this awesome amount of energy. This is indeed as one can only hope; an explosion of such an awesome amount of energy would blow to pieces the physicist who had the misfortune of finding a way to produce it.

  He may not have been the first person to notice this consequence of Einstein’s work, but he was certainly one of the very few at the time who emphasized its importance. In light of what life had in store for him, his words are particularly prophetic. Years later, as he witnessed the first test of an atomic bomb and considered his role in making that test possible, he certainly thought back to these words, written when he was just twenty-one years old.

  By the time he graduated in July 1922, Fermi was an expert on relativity and its strongest—perhaps only—proponent within the Italian physics community. Although the subject was not yet on the radar screen of most Italian physicists, it was of great interest to Italian mathematicians, who pioneered the mathematics necessary for the theory, in particular the brilliant University of Rome mathematician Tullio Levi-Civita. Einstein had consulted Levi-Civita as he struggled with the theory. The Italian had made some essential suggestions and kept abreast of Einstein’s revolutionary work. So impressed was Levi-Civita with Fermi’s work on relativity that he used Fermi’s coordinate system in his own treatise in 1925. After Fermi’s graduation, it was the mathematicians who first appreciated his potential for transforming physics in Italy.

  FERMI WENT ON TO COMPLETE HIS UNIVERSITY PHYSICS DISSERTATION on X-ray diffraction with little trouble. The results were a series of images made with X-rays passed through crystals and Fermi’s analysis of these images. He graduated with honors. His dissertation at the Scuola Normale was more theoretical, involving the solution of a particular theorem in probability and its application to the orbit of a comet. Fermi was more nervous about this dissertation for the Scuola Normale than he was about the university degree. He was concerned that someone else had already proven a theorem he was working on and that someone had applied these theorems to the orbit of asteroids. So fretful was he, in fact, that he wrote to Persico several times to see if his friend in Rome could do some independent research to determine whether his worries were founded.

  As it turned out, the exam was not smooth sailing, but not because of the issue of prior work. During his oral exams, several of the examiners were mathematici
ans who grilled him hard on the equations he used. In the end he received a licenza, but the examiners did not offer him the customary handshake, nor was the thesis published, as was the tradition at the Scuola Normale. Years later his wife would claim that the thesis went over the heads of the examiners. This seems unlikely. It is more likely that they were simply exacting revenge on a renegade mathematics student who offended them by abandoning the rarified field of mathematics for the less cerebral, earthier pursuit of physics.

  IN THE SUMMER OF 1922, DEGREES IN HAND, FERMI, ALREADY A legend in Pisa, headed home to Rome. Because he had come to the notice of major figures in the mathematics community in Italy, Fermi was a frequent visitor to the Saturday evening salons held at the home of Levi-Civita’s friend and colleague Guido Castelnuovo in Rome. Word of Fermi’s brilliance had spread to the dean of Italian physics, Orso Mario Corbino. A man of extraordinary power and influence, Corbino was the director of the Institute of Physics at the University of Rome. He soon understood exactly what Fermi could do for Italian physics and he was determined to make sure the young man succeeded.

  CHAPTER THREE

  GERMANY AND HOLLAND

  FERMI’S FOUR YEARS IN PISA WERE SCHOLARLY AND CONTEMPLATIVE, but they were years of turmoil and chaos for the rest of the country. Though Italy was one of the victors in November 1918, the war left a power vacuum in its wake, and the following four years saw one faction after another trying to grab the political high ground. Strikes and labor unrest led to regular breakdowns in production and transportation. In the streets of the northern industrial cities of Milan, Turin, and Genoa, communists and right-wing agitators fought each other with increasing violence and lawlessness. Virulent Italian nationalists sought a voice in parliament. Italy seemed increasingly ungovernable.