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Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian (later
naturalized Naturalization (or naturalisation) is the legal act or process by which a non-citizen of a country may acquire citizenship or nationality of that country. It may be done automatically by a statute, i.e., without any effort on the part of the in ...
American) physicist and the creator of the world's first
nuclear reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nu ...
, the
Chicago Pile-1 Chicago Pile-1 (CP-1) was the world's first artificial nuclear reactor. On 2 December 1942, the first human-made self-sustaining nuclear chain reaction was initiated in CP-1, during an experiment led by Enrico Fermi. The secret development of t ...
. He has been called the "architect of the
nuclear age The Atomic Age, also known as the Atomic Era, is the period of history following the detonation of the first nuclear weapon, The Gadget at the ''Trinity'' test in New Mexico, on July 16, 1945, during World War II. Although nuclear chain reaction ...
" and the "architect of the atomic bomb". He was one of very few physicists to excel in both
theoretical physics Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experim ...
and
experimental physics Experimental physics is the category of disciplines and sub-disciplines in the field of physics that are concerned with the observation of physical phenomena and experiments. Methods vary from discipline to discipline, from simple experiments and ...
. Fermi was awarded the 1938
Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...
for his work on induced radioactivity by neutron bombardment and for the discovery of
transuranium elements The transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92, which is the atomic number of uranium. All of these elements are unstable and decay radioactively into other elements. ...
. With his colleagues, Fermi filed several patents related to the use of nuclear power, all of which were taken over by the US government. He made significant contributions to the development of
statistical mechanics In physics, statistical mechanics is a mathematical framework that applies statistical methods and probability theory to large assemblies of microscopic entities. It does not assume or postulate any natural laws, but explains the macroscopic be ...
,
quantum theory Quantum theory may refer to: Science *Quantum mechanics, a major field of physics *Old quantum theory, predating modern quantum mechanics * Quantum field theory, an area of quantum mechanics that includes: ** Quantum electrodynamics ** Quantum ch ...
, and
nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: * Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics *Nuclear space *Nuclear ...
and
particle physics Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) an ...
. Fermi's first major contribution involved the field of statistical mechanics. After
Wolfgang Pauli Wolfgang Ernst Pauli (; ; 25 April 1900 – 15 December 1958) was an Austrian theoretical physicist and one of the pioneers of quantum physics. In 1945, after having been nominated by Albert Einstein, Pauli received the Nobel Prize in Physics fo ...
formulated his exclusion principle in 1925, Fermi followed with a paper in which he applied the principle to an ideal gas, employing a statistical formulation now known as
Fermi–Dirac statistics Fermi–Dirac statistics (F–D statistics) is a type of quantum statistics that applies to the physics of a system consisting of many non-interacting, identical particles that obey the Pauli exclusion principle. A result is the Fermi–Dirac di ...
. Today, particles that obey the exclusion principle are called "
fermion In particle physics, a fermion is a particle that follows Fermi–Dirac statistics. Generally, it has a half-odd-integer spin: spin , spin , etc. In addition, these particles obey the Pauli exclusion principle. Fermions include all quarks an ...
s". Pauli later postulated the existence of an uncharged invisible particle emitted along with an
electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no kn ...
during
beta decay In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For ...
, to satisfy the law of
conservation of energy In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be ''conserved'' over time. This law, first proposed and tested by Émilie du Châtelet, means th ...
. Fermi took up this idea, developing a model that incorporated the postulated particle, which he named the " neutrino". His theory, later referred to as
Fermi's interaction In particle physics, Fermi's interaction (also the Fermi theory of beta decay or the Fermi four-fermion interaction) is an explanation of the beta decay, proposed by Enrico Fermi in 1933. The theory posits four fermions directly interactin ...
and now called weak interaction, described one of the four fundamental interactions in nature. Through experiments inducing radioactivity with the recently discovered
neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...
, Fermi discovered that slow neutrons were more easily captured by
atomic nuclei The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron ...
than fast ones, and he developed the
Fermi age equation Nuclear reactor physics is the field of physics that studies and deals with the applied study and engineering applications of chain reaction to induce a controlled rate of fission in a nuclear reactor for the production of energy.van Dam, H., ...
to describe this. After bombarding
thorium Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high me ...
and
uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...
with slow neutrons, he concluded that he had created new elements. Although he was awarded the Nobel Prize for this discovery, the new elements were later revealed to be nuclear fission products. Fermi left Italy in 1938 to escape new Italian racial laws that affected his Jewish wife,
Laura Capon Laura Capon Fermi (Rome, 16 June 1907 – Chicago, 26 December 1977) was an Italian and naturalized-American writer and political activist. She was the wife of Nobel Prize physicist Enrico Fermi. Biography Laura Capon was born in Rome in 1907. ...
. He emigrated to the United States, where he worked on the
Manhattan Project The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...
during World War II. Fermi led the team at the
University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park neighborhood. The University of Chicago is consistently ranked among the b ...
that designed and built Chicago Pile-1, which went
critical Critical or Critically may refer to: *Critical, or critical but stable, medical states **Critical, or intensive care medicine *Critical juncture, a discontinuous change studied in the social sciences. *Critical Software, a company specializing in ...
on 2 December 1942, demonstrating the first human-created, self-sustaining
nuclear chain reaction In nuclear physics, a nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series of these reactions. The specific nu ...
. He was on hand when the X-10 Graphite Reactor at
Oak Ridge, Tennessee Oak Ridge is a city in Anderson and Roane counties in the eastern part of the U.S. state of Tennessee, about west of downtown Knoxville. Oak Ridge's population was 31,402 at the 2020 census. It is part of the Knoxville Metropolitan Area. Oak ...
, went critical in 1943, and when the
B Reactor The B Reactor at the Hanford Site, near Richland, Washington, was the first large-scale nuclear reactor ever built. The project was a key part of the Manhattan Project, the United States nuclear weapons development program during World War II. I ...
at the Hanford Site did so the next year. At Los Alamos, he headed F Division, part of which worked on Edward Teller's
thermonuclear Thermonuclear fusion is the process of atomic nuclei combining or “fusing” using high temperatures to drive them close enough together for this to become possible. There are two forms of thermonuclear fusion: ''uncontrolled'', in which the re ...
"
Super Super may refer to: Computing * SUPER (computer program), or Simplified Universal Player Encoder & Renderer, a video converter / player * Super (computer science), a keyword in object-oriented programming languages * Super key (keyboard butt ...
" bomb. He was present at the Trinity test on 16 July 1945, where he used his
Fermi method In physics or engineering education, a Fermi problem, Fermi quiz, Fermi question, Fermi estimate, order-of-magnitude problem, order-of-magnitude estimate, or order estimation is an estimation problem designed to teach dimensional analysis or a ...
to estimate the bomb's yield. After the war, Fermi served under J. Robert Oppenheimer on the General Advisory Committee, which advised the Atomic Energy Commission on nuclear matters. After the detonation of the first Soviet
fission bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions (thermonuclear bomb), producing a nuclear explosion. Both bomb ...
in August 1949, he strongly opposed the development of a hydrogen bomb on both moral and technical grounds. He was among the scientists who testified on Oppenheimer's behalf at the 1954 hearing that resulted in the denial of Oppenheimer's security clearance. Fermi did important work in particle physics, especially related to pions and
muon A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of , but with a much greater mass. It is classified as a lepton. As wi ...
s, and he speculated that
cosmic ray Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...
s arose when material was accelerated by magnetic fields in interstellar space. Many awards, concepts, and institutions are named after Fermi, including the
Enrico Fermi Award The Enrico Fermi Award is a scientific award conferred by the President of the United States. It is awarded to honor scientists of international stature for their lifetime achievement in the development, use, or production of energy. It was establ ...
, the Enrico Fermi Institute, the Fermi National Accelerator Laboratory (Fermilab), the Fermi Gamma-ray Space Telescope, and the synthetic element
fermium Fermium is a synthetic element with the symbol Fm and atomic number 100. It is an actinide and the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic qua ...
, making him one of 16 scientists who have elements named after them. Fermi tutored or directly influenced no fewer than eight young researchers who went on to win Nobel Prizes.


Early life

Enrico Fermi was born in Rome, Italy, on 29 September 1901. He was the third child of Alberto Fermi, a division head in the Ministry of Railways, and Ida de Gattis, an elementary school teacher. His sister, Maria, was two years older, his brother Giulio a year older. After the two boys were sent to a rural community to be wet nursed, Enrico rejoined his family in Rome when he was two and a half. Although he was baptized a
Roman Catholic Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *'' Epistle to the Romans'', shortened to ''Romans'', a lette ...
in accordance with his grandparents' wishes, his family was not particularly religious; Enrico was an
agnostic Agnosticism is the view or belief that the existence of God, of the divine or the supernatural is unknown or unknowable. (page 56 in 1967 edition) Another definition provided is the view that "human reason is incapable of providing sufficient ...
throughout his adult life. As a young boy, he shared the same interests as his brother Giulio, building
electric motor An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagneti ...
s and playing with electrical and mechanical toys. Giulio died during an operation on a throat
abscess An abscess is a collection of pus that has built up within the tissue of the body. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pressed. The area of redness often extends b ...
in 1915 and Maria died in an airplane crash near
Milan Milan ( , , Lombard: ; it, Milano ) is a city in northern Italy, capital of Lombardy, and the second-most populous city proper in Italy after Rome. The city proper has a population of about 1.4 million, while its metropolitan city h ...
in 1959. At a local market in
Campo de' Fiori Campo de' Fiori (, literally "field of flowers") is a rectangular square south of Piazza Navona in Rome, Italy, at the border between rione Parione and rione Regola. It is diagonally southeast of the Palazzo della Cancelleria and one block north ...
Fermi found a physics book, the 900-page ''Elementorum physicae mathematicae''. Written in Latin by
Jesuit , image = Ihs-logo.svg , image_size = 175px , caption = ChristogramOfficial seal of the Jesuits , abbreviation = SJ , nickname = Jesuits , formation = , founders ...
Father , a professor at the Collegio Romano, it presented
mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...
,
classical mechanics Classical mechanics is a physical theory describing the motion of macroscopic objects, from projectiles to parts of machinery, and astronomical objects, such as spacecraft, planets, stars, and galaxies. For objects governed by classical ...
,
astronomy Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest ...
,
optics Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...
, and
acoustics Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician ...
as they were understood at the time of its 1840 publication. With a scientifically inclined friend,
Enrico Persico Enrico Persico (August 9, 1900 – June 17, 1969) was an Italian physicist notable for propagating the field of quantum mechanics in Italy. He was a professor at the University of Turin and is also notable as the doctoral advisor of Ugo Fano. Care ...
, Fermi pursued projects such as building
gyroscope A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining orientation and angular velocity. It is a spinning wheel or disc in which the axis of rota ...
s and measuring the acceleration of
Earth's gravity The gravity of Earth, denoted by , is the net acceleration that is imparted to objects due to the combined effect of gravitation (from mass distribution within Earth) and the centrifugal force (from the Earth's rotation). It is a vector quantity ...
. In 1914, Fermi, who used to often meet with his father in front of the office after work, met a colleague of his father called Adolfo Amidei, who would walk part of the way home with Alberto. Enrico had learned that Adolfo was interested in mathematics and physics and took the opportunity to ask Adolfo a question about geometry. Adolfo understood that the young Fermi was referring to projective geometry and then proceeded to give him a book on the subject written by
Theodor Reye Karl Theodor Reye (born 20 June 1838 in Ritzebüttel, Germany and died 2 July 1919 in Würzburg, Germany) was a German mathematician. He contributed to geometry, particularly projective geometry and synthetic geometry. He is best known for his ...
. Two months later, Fermi returned the book, having solved all the problems proposed at the end of the book, some of which Adolfo considered difficult. Upon verifying this, Adolfo felt that Fermi was "a prodigy, at least with respect to geometry", and further mentored the boy, providing him with more books on physics and mathematics. Adolfo noted that Fermi had a very good memory and thus could return the books after having read them because he could remember their content very well.


''Scuola Normale Superiore'' in Pisa

Fermi graduated from high school in July 1918, having skipped the third year entirely. At Amidei's urging, Fermi learned
German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ger ...
to be able to read the many scientific papers that were published in that language at the time, and he applied to the ''
Scuola Normale Superiore The Scuola Normale Superiore in Pisa (commonly known in Italy as "la Normale") is a public university in Pisa and Florence, Tuscany, Italy, currently attended by about 600 undergraduate and postgraduate (PhD) students. It was founded in 1810 wi ...
'' in
Pisa Pisa ( , or ) is a city and ''comune'' in Tuscany, central Italy, straddling the Arno just before it empties into the Ligurian Sea. It is the capital city of the Province of Pisa. Although Pisa is known worldwide for its leaning tower, the cit ...
. Amidei felt that the Scuola would provide better conditions for Fermi's development than the Sapienza University of Rome could at the time. Having lost one son, Fermi's parents only reluctantly allowed him to live in the school's lodgings away from Rome for four years. Fermi took first place in the difficult entrance exam, which included an essay on the theme of "Specific characteristics of Sounds"; the 17-year-old Fermi chose to use
Fourier analysis In mathematics, Fourier analysis () is the study of the way general functions may be represented or approximated by sums of simpler trigonometric functions. Fourier analysis grew from the study of Fourier series, and is named after Josep ...
to derive and solve the
partial differential equation In mathematics, a partial differential equation (PDE) is an equation which imposes relations between the various partial derivatives of a Multivariable calculus, multivariable function. The function is often thought of as an "unknown" to be sol ...
for a vibrating rod, and after interviewing Fermi the examiner declared he would become an outstanding physicist. At the ''Scuola Normale Superiore'', Fermi played pranks with fellow student
Franco Rasetti Franco Dino Rasetti (August 10, 1901 – December 5, 2001) was an Italian (later naturalized American) physicist, paleontologist and botanist. Together with Enrico Fermi, he discovered key processes leading to nuclear fission. Rasetti refused ...
; the two became close friends and collaborators. Fermi was advised by
Luigi Puccianti Luigi Puccianti (; 11 June 1875 – 9 June 1952) was an Italian physicist. Career In 1899–1900, Puccianti constructed a highly sensitive spectrograph, with which he studied the infrared absorption of many compounds and attempted to correlate th ...
, director of the physics laboratory, who said there was little he could teach Fermi and often asked Fermi to teach him something instead. Fermi's knowledge of quantum physics was such that Puccianti asked him to organize seminars on the topic. During this time Fermi learned tensor calculus, a technique key to
general relativity General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics ...
. Fermi initially chose mathematics as his major, but soon switched to physics. He remained largely self-taught, studying general relativity,
quantum mechanics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...
, and
atomic physics Atomic physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. Atomic physics typically refers to the study of atomic structure and the interaction between atoms. It is primarily concerned wit ...
. In September 1920, Fermi was admitted to the Physics department. Since there were only three students in the department—Fermi, Rasetti, and
Nello Carrara Nello Carrara (19 February 1900 – 5 June 1993) was an Italian physicist and founder of the Electromagnetic Wave Research Institute. He researched X-rays and was a pioneer of radar, but is best known for coining the term "microwave". Bio ...
—Puccianti let them freely use the laboratory for whatever purposes they chose. Fermi decided that they should research
X-ray crystallography X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...
, and the three worked to produce a Laue photograph—an X-ray photograph of a crystal. During 1921, his third year at the university, Fermi published his first scientific works in the Italian journal ''
Nuovo Cimento ''Nuovo Cimento'' is a series of peer-reviewed scientific journals of physics. The series was first established in 1855, when Carlo Matteucci and Raffaele Piria started publishing ''Il Nuovo Cimento'' as the continuation of ''Il Cimento'', which ...
''. The first was entitled "On the dynamics of a rigid system of electrical charges in translational motion" ('). A sign of things to come was that the
mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementar ...
was expressed as a
tensor In mathematics, a tensor is an algebraic object that describes a multilinear relationship between sets of algebraic objects related to a vector space. Tensors may map between different objects such as vectors, scalars, and even other tenso ...
—a mathematical construct commonly used to describe something moving and changing in three-dimensional space. In classical mechanics, mass is a
scalar Scalar may refer to: *Scalar (mathematics), an element of a field, which is used to define a vector space, usually the field of real numbers * Scalar (physics), a physical quantity that can be described by a single element of a number field such ...
quantity, but in relativity, it changes with velocity. The second paper was "On the electrostatics of a uniform gravitational field of electromagnetic charges and on the weight of electromagnetic charges" ('). Using general relativity, Fermi showed that a charge has a weight equal to U/c2, where U was the electrostatic energy of the system, and c is the
speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit ...
. The first paper seemed to point out a contradiction between the electrodynamic theory and the relativistic one concerning the calculation of the electromagnetic masses, as the former predicted a value of 4/3 U/c2. Fermi addressed this the next year in a paper "Concerning a contradiction between
electrodynamic In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of a ...
and the relativistic theory of electromagnetic mass" in which he showed that the apparent contradiction was a consequence of relativity. This paper was sufficiently well-regarded that it was translated into German and published in the German scientific journal ''
Physikalische Zeitschrift ''Physikalische Zeitschrift'' (English: ''Physical Journal'') was a German scientific journal of physics published from 1899 to 1945 by S. Hirzel Verlag. In 1924, it merged with ''Jahrbuch der Radioaktivität und Elektronik''. From 1944 onwards, ...
'' in 1922. That year, Fermi submitted his article "On the phenomena occurring near a
world line The world line (or worldline) of an object is the path that an object traces in 4-dimensional spacetime. It is an important concept in modern physics, and particularly theoretical physics. The concept of a "world line" is distinguished from con ...
" (') to the Italian journal '. In this article he examined the
Principle of Equivalence In the theory of general relativity, the equivalence principle is the equivalence of gravitational and inertial mass, and Albert Einstein's observation that the gravitational "force" as experienced locally while standing on a massive body (suc ...
, and introduced the so-called "
Fermi coordinates In the mathematical theory of Riemannian geometry, there are two uses of the term Fermi coordinates. In one use they are local coordinates that are adapted to a geodesic. In a second, more general one, they are local coordinates that are adapted to ...
". He proved that on a world line close to the timeline, space behaves as if it were a
Euclidean space Euclidean space is the fundamental space of geometry, intended to represent physical space. Originally, that is, in Euclid's Elements, Euclid's ''Elements'', it was the three-dimensional space of Euclidean geometry, but in modern mathematics ther ...
. Fermi submitted his thesis, "A theorem on probability and some of its applications" ('), to the ''Scuola Normale Superiore'' in July 1922, and received his laurea at the unusually young age of 20. The thesis was on
X-ray diffraction X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...
images.
Theoretical physics Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experim ...
was not yet considered a discipline in Italy, and the only thesis that would have been accepted was
experimental physics Experimental physics is the category of disciplines and sub-disciplines in the field of physics that are concerned with the observation of physical phenomena and experiments. Methods vary from discipline to discipline, from simple experiments and ...
. For this reason, Italian physicists were slow in embracing the new ideas like relativity coming from Germany. Since Fermi was quite at home in the lab doing experimental work, this did not pose insurmountable problems for him. While writing the appendix for the Italian edition of the book ''Fundamentals of Einstein Relativity'' by August Kopff in 1923, Fermi was the first to point out that hidden inside the
Einstein equation In the general theory of relativity, the Einstein field equations (EFE; also known as Einstein's equations) relate the geometry of spacetime to the distribution of matter within it. The equations were published by Einstein in 1915 in the form ...
() was an enormous amount of
nuclear potential energy In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors. Common types of potential energy include the gravitational potentia ...
to be exploited. "It does not seem possible, at least in the near future", he wrote, "to find a way to release these dreadful amounts of energy—which is all to the good because the first effect of an explosion of such a dreadful amount of energy would be to smash into smithereens the physicist who had the misfortune to find a way to do it." In 1924, Fermi was initiated into the Masonic Lodge "Adriano Lemmi" of the
Grand Orient of Italy The Grand Orient of Italy (GOI) ( it, Grande Oriente d'Italia) is an Italian masonic grand lodge founded in 1805; the viceroy Eugene of Beauharnais was instrumental in its establishment. It was based at the Palazzo Giustiniani, Rome, Italy fr ...
. In 1923–1924, Fermi spent a semester studying under
Max Born Max Born (; 11 December 1882 – 5 January 1970) was a German physicist and mathematician who was instrumental in the development of quantum mechanics. He also made contributions to solid-state physics and optics and supervised the work of a n ...
at the
University of Göttingen The University of Göttingen, officially the Georg August University of Göttingen, (german: Georg-August-Universität Göttingen, known informally as Georgia Augusta) is a public research university in the city of Göttingen, Germany. Founded ...
, where he met
Werner Heisenberg Werner Karl Heisenberg () (5 December 1901 – 1 February 1976) was a German theoretical physicist and one of the main pioneers of the theory of quantum mechanics. He published his work in 1925 in a breakthrough paper. In the subsequent series ...
and Pascual Jordan. Fermi then studied in
Leiden Leiden (; in English and archaic Dutch also Leyden) is a city and municipality in the province of South Holland, Netherlands. The municipality of Leiden has a population of 119,713, but the city forms one densely connected agglomeration wit ...
with
Paul Ehrenfest Paul Ehrenfest (18 January 1880 – 25 September 1933) was an Austrian theoretical physicist, who made major contributions to the field of statistical mechanics and its relations with quantum mechanics, including the theory of phase transition an ...
from September to December 1924 on a fellowship from the
Rockefeller Foundation The Rockefeller Foundation is an American private foundation and philanthropic medical research and arts funding organization based at 420 Fifth Avenue, New York City. The second-oldest major philanthropic institution in America, after the Carneg ...
obtained through the intercession of the mathematician Vito Volterra. Here Fermi met
Hendrik Lorentz Hendrik Antoon Lorentz (; 18 July 1853 – 4 February 1928) was a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect. He also derived the Lorentz t ...
and
Albert Einstein Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory ...
, and became friends with Samuel Goudsmit and Jan Tinbergen. From January 1925 to late 1926, Fermi taught
mathematical physics Mathematical physics refers to the development of mathematics, mathematical methods for application to problems in physics. The ''Journal of Mathematical Physics'' defines the field as "the application of mathematics to problems in physics and t ...
and theoretical mechanics at the University of Florence, where he teamed up with Rasetti to conduct a series of experiments on the effects of magnetic fields on mercury vapor. He also participated in seminars at the Sapienza University of Rome, giving lectures on quantum mechanics and
solid state physics Solid-state physics is the study of rigid matter, or solids, through methods such as quantum mechanics, crystallography, electromagnetism, and metallurgy. It is the largest branch of condensed matter physics. Solid-state physics studies how the l ...
. While giving lectures on the new quantum mechanics based on the remarkable accuracy of predictions of the Schrödinger equation, Fermi would often say, "It has no business to fit so well!" After
Wolfgang Pauli Wolfgang Ernst Pauli (; ; 25 April 1900 – 15 December 1958) was an Austrian theoretical physicist and one of the pioneers of quantum physics. In 1945, after having been nominated by Albert Einstein, Pauli received the Nobel Prize in Physics fo ...
announced his exclusion principle in 1925, Fermi responded with a paper "On the quantization of the perfect monoatomic gas" ('), in which he applied the exclusion principle to an ideal gas. The paper was especially notable for Fermi's statistical formulation, which describes the distribution of particles in
systems A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and express ...
of many identical particles that obey the exclusion principle. This was independently developed soon after by the British physicist
Paul Dirac Paul Adrien Maurice Dirac (; 8 August 1902 – 20 October 1984) was an English theoretical physicist who is regarded as one of the most significant physicists of the 20th century. He was the Lucasian Professor of Mathematics at the Univer ...
, who also showed how it was related to the Bose–Einstein statistics. Accordingly, it is now known as
Fermi–Dirac statistics Fermi–Dirac statistics (F–D statistics) is a type of quantum statistics that applies to the physics of a system consisting of many non-interacting, identical particles that obey the Pauli exclusion principle. A result is the Fermi–Dirac di ...
. After Dirac, particles that obey the exclusion principle are today called "
fermion In particle physics, a fermion is a particle that follows Fermi–Dirac statistics. Generally, it has a half-odd-integer spin: spin , spin , etc. In addition, these particles obey the Pauli exclusion principle. Fermions include all quarks an ...
s", while those that do not are called " bosons".


Professor in Rome

Professorships in Italy were granted by competition (') for a vacant chair, the applicants being rated on their publications by a committee of professors. Fermi applied for a chair of mathematical physics at the
University of Cagliari The University of Cagliari ( it, Università degli Studi di Cagliari) is a university in Cagliari, Sardinia, Italy. It was founded in 1606 and is organized in 11 faculties. History The ''Studium Generalis Kalaritanum'' was founded in 1606 alon ...
on
Sardinia Sardinia ( ; it, Sardegna, label=Italian, Corsican and Tabarchino ; sc, Sardigna , sdc, Sardhigna; french: Sardaigne; sdn, Saldigna; ca, Sardenya, label=Algherese and Catalan) is the second-largest island in the Mediterranean Sea, after ...
, but was narrowly passed over in favor of
Giovanni Giorgi Giovanni Giorgi (November 27, 1871 – August 19, 1950) was an Italian physicist and electrical engineer who proposed the ''Giorgi system'' of measurement, the precursor to the International System of Units (SI). Early Life Giovanni Giorgi was bo ...
. In 1926, at the age of 24, he applied for a professorship at the Sapienza University of Rome. This was a new chair, one of the first three in theoretical physics in Italy, that had been created by the Minister of Education at the urging of Professor Orso Mario Corbino, who was the university's professor of experimental physics, the Director of the Institute of Physics, and a member of
Benito Mussolini Benito Amilcare Andrea Mussolini (; 29 July 188328 April 1945) was an Italian politician and journalist who founded and led the National Fascist Party. He was Prime Minister of Italy from the March on Rome in 1922 until his deposition in 194 ...
's cabinet. Corbino, who also chaired the selection committee, hoped that the new chair would raise the standard and reputation of physics in Italy. The committee chose Fermi ahead of Enrico Persico and
Aldo Pontremoli Aldo Pontremoli (; 19 January 1896 – 25 May 1928) was an Italian physicist who held a chair of theoretical physics at the Milan school of physics, Physics Department of the University of Milan from 1926 and who founded and directed the Instit ...
, and Corbino helped Fermi recruit his team, which was soon joined by notable students such as Edoardo Amaldi,
Bruno Pontecorvo Bruno Pontecorvo (; russian: Бру́но Макси́мович Понтеко́рво, ''Bruno Maksimovich Pontecorvo''; 22 August 1913 – 24 September 1993) was an Italian and Soviet nuclear physicist, an early assistant of Enrico Fermi an ...
, Ettore Majorana and Emilio Segrè, and by Franco Rasetti, whom Fermi had appointed as his assistant. They soon nicknamed the " Via Panisperna boys" after the street where the Institute of Physics was located. Fermi married
Laura Capon Laura Capon Fermi (Rome, 16 June 1907 – Chicago, 26 December 1977) was an Italian and naturalized-American writer and political activist. She was the wife of Nobel Prize physicist Enrico Fermi. Biography Laura Capon was born in Rome in 1907. ...
, a science student at the university, on 19 July 1928. They had two children: Nella, born in January 1931, and Giulio, born in February 1936. On 18 March 1929, Fermi was appointed a member of the Royal Academy of Italy by Mussolini, and on 27 April he joined the
Fascist Party The National Fascist Party ( it, Partito Nazionale Fascista, PNF) was a political party in Italy, created by Benito Mussolini as the political expression of Italian Fascism and as a reorganization of the previous Italian Fasces of Combat. The ...
. He later opposed Fascism when the 1938
racial laws Anti-Jewish laws have been a common occurrence throughout Jewish history. Examples of such laws include special Jewish quotas, Jewish taxes and Disabilities (Jewish), Jewish "disabilities". Some were adopted in the 1930s and 1940s in Nazi Germany ...
were promulgated by Mussolini in order to bring Italian Fascism ideologically closer to German
Nazism Nazism ( ; german: Nazismus), the common name in English for National Socialism (german: Nationalsozialismus, ), is the far-right totalitarian political ideology and practices associated with Adolf Hitler and the Nazi Party (NSDAP) in Na ...
. These laws threatened Laura, who was Jewish, and put many of Fermi's research assistants out of work. During their time in Rome, Fermi and his group made important contributions to many practical and theoretical aspects of physics. In 1928, he published his ''Introduction to Atomic Physics'' ('), which provided Italian university students with an up-to-date and accessible text. Fermi also conducted public lectures and wrote popular articles for scientists and teachers in order to spread knowledge of the new physics as widely as possible. Part of his teaching method was to gather his colleagues and graduate students together at the end of the day and go over a problem, often from his own research. A sign of success was that foreign students now began to come to Italy. The most notable of these was the German physicist Hans Bethe, who came to Rome as a Rockefeller Foundation fellow, and collaborated with Fermi on a 1932 paper "On the Interaction between Two Electrons" (). At this time, physicists were puzzled by
beta decay In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For ...
, in which an
electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no kn ...
was emitted from the
atomic nucleus The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron i ...
. To satisfy the law of
conservation of energy In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be ''conserved'' over time. This law, first proposed and tested by Émilie du Châtelet, means th ...
, Pauli postulated the existence of an invisible particle with no charge and little or no mass that was also emitted at the same time. Fermi took up this idea, which he developed in a tentative paper in 1933, and then a longer paper the next year that incorporated the postulated particle, which Fermi called a " neutrino". His theory, later referred to as
Fermi's interaction In particle physics, Fermi's interaction (also the Fermi theory of beta decay or the Fermi four-fermion interaction) is an explanation of the beta decay, proposed by Enrico Fermi in 1933. The theory posits four fermions directly interactin ...
, and still later as the theory of the weak interaction, described one of the four fundamental forces of nature. The neutrino was detected after his death, and his interaction theory showed why it was so difficult to detect. When he submitted his paper to the British journal ''
Nature Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...
'', that journal's editor turned it down because it contained speculations which were "too remote from physical reality to be of interest to readers". Thus Fermi saw the theory published in Italian and German before it was published in English. In the introduction to the 1968 English translation, physicist Fred L. Wilson noted that: In January 1934, Irène Joliot-Curie and
Frédéric Joliot Frédéric and Frédérick are the French versions of the common male given name Frederick. They may refer to: In artistry: * Frédéric Back, Canadian award-winning animator * Frédéric Bartholdi, French sculptor * Frédéric Bazille, Impress ...
announced that they had bombarded elements with
alpha particle Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay, but may also be produce ...
s and induced radioactivity in them. By March, Fermi's assistant
Gian-Carlo Wick Gian Carlo Wick (15 October 1909 – 20 April 1992) was an Italian theoretical physicist who made important contributions to quantum field theory. The Wick rotation, Wick contraction, Wick's theorem, and the Wick product are named after him.
had provided a theoretical explanation using Fermi's theory of beta decay. Fermi decided to switch to experimental physics, using the
neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...
, which James Chadwick had discovered in 1932. In March 1934, Fermi wanted to see if he could induce radioactivity with Rasetti's polonium-
beryllium Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form mi ...
neutron source. Neutrons had no electric charge, and so would not be deflected by the positively charged nucleus. This meant that they needed much less energy to penetrate the nucleus than charged particles, and so would not require a particle accelerator, which the Via Panisperna boys did not have. Fermi had the idea to resort to replacing the polonium-beryllium neutron source with a
radon Radon is a chemical element with the symbol Rn and atomic number 86. It is a radioactive, colourless, odourless, tasteless noble gas. It occurs naturally in minute quantities as an intermediate step in the normal radioactive decay chains through ...
-beryllium one, which he created by filling a glass bulb with beryllium powder, evacuating the air, and then adding 50 m Ci of radon gas, supplied by
Giulio Cesare Trabacchi Giulio () is an Italian given name. Notable people with the name include: * Giulio Alberoni (1664–1752), Italian cardinal and statesman * Giulio Alenio (1582–1649), Italian Jesuit missionary and scholar * Giulio Alfieri (1924–2002), Italian a ...
. This created a much stronger neutron source, the effectiveness of which declined with the 3.8-day
half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable ato ...
of radon. He knew that this source would also emit
gamma ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...
s, but, on the basis of his theory, he believed that this would not affect the results of the experiment. He started by bombarding
platinum Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish , a diminutive of "silver". Platinu ...
, an element with a high
atomic number The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of an atomic nucleus. For ordinary nuclei, this is equal to the proton number (''n''p) or the number of protons found in the nucleus of every ...
that was readily available, without success. He turned to
aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...
, which emitted an alpha particle and produced
sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...
, which then decayed into
magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
by beta particle emission. He tried
lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
, without success, and then
fluorine Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...
in the form of calcium fluoride, which emitted an alpha particle and produced
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
, decaying into
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
by beta particle emission. In all, he induced radioactivity in 22 different elements. Fermi rapidly reported the discovery of neutron-induced radioactivity in the Italian journal ''La Ricerca Scientifica'' on 25 March 1934. The natural radioactivity of
thorium Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high me ...
and
uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...
made it hard to determine what was happening when these elements were bombarded with neutrons but, after correctly eliminating the presence of elements lighter than uranium but heavier than lead, Fermi concluded that they had created new elements, which he called
hesperium Hesperium (or esperium; atomic symbol Es) was the name assigned to the element with atomic number 94, now known as plutonium. It was named in Italian ''Esperio'' after a Greek name of Italy, Hesperia, "the land of the West". The same team assigned ...
and
ausonium Ausenium (atomic symbol Ao) was the name assigned to the element with atomic number 93, now known as neptunium. It was named after a Greek name of Italy, Ausonia (disambiguation), Ausonia. The same team assigned the name hesperium to element 94, ...
. The chemist
Ida Noddack Ida Noddack (25 February 1896 – 24 September 1978), ''née'' Tacke, was a German chemist and physicist. In 1934 she was the first to mention the idea later named nuclear fission. With her husband - Walter Noddack - and Otto Berg she discover ...
suggested that some of the experiments could have produced lighter elements than lead rather than new, heavier elements. Her suggestion was not taken seriously at the time because her team had not carried out any experiments with uranium or built the theoretical basis for this possibility. At that time, fission was thought to be improbable if not impossible on theoretical grounds. While physicists expected elements with higher atomic numbers to form from neutron bombardment of lighter elements, nobody expected neutrons to have enough energy to split a heavier atom into two light element fragments in the manner that Noddack suggested. The Via Panisperna boys also noticed some unexplained effects. The experiment seemed to work better on a wooden table than a marble tabletop. Fermi remembered that Joliot-Curie and Chadwick had noted that
paraffin wax Paraffin wax (or petroleum wax) is a soft colorless solid derived from petroleum, coal, or oil shale that consists of a mixture of hydrocarbon molecules containing between 20 and 40 carbon atoms. It is solid at room temperature and begins to m ...
was effective at slowing neutrons, so he decided to try that. When neutrons were passed through paraffin wax, they induced a hundred times as much radioactivity in
silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...
compared with when it was bombarded without the paraffin. Fermi guessed that this was due to the hydrogen atoms in the paraffin. Those in wood similarly explained the difference between the wooden and the marble tabletops. This was confirmed by repeating the effect with water. He concluded that collisions with hydrogen atoms slowed the neutrons. The lower the atomic number of the nucleus it collides with, the more energy a neutron loses per collision, and therefore the fewer collisions that are required to slow a neutron down by a given amount. Fermi realised that this induced more radioactivity because slow neutrons were more easily captured than fast ones. He developed a
diffusion equation The diffusion equation is a parabolic partial differential equation. In physics, it describes the macroscopic behavior of many micro-particles in Brownian motion, resulting from the random movements and collisions of the particles (see Fick's la ...
to describe this, which became known as the
Fermi age equation Nuclear reactor physics is the field of physics that studies and deals with the applied study and engineering applications of chain reaction to induce a controlled rate of fission in a nuclear reactor for the production of energy.van Dam, H., ...
. In 1938, Fermi received the
Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...
at the age of 37 for his "demonstrations of the existence of new radioactive elements produced by neutron irradiation, and for his related discovery of
nuclear reaction In nuclear physics and nuclear chemistry, a nuclear reaction is a process in which two atomic nucleus, nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides. Thus, a nuclear reaction must cause a t ...
s brought about by slow neutrons". After Fermi received the prize in
Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...
, he did not return home to Italy but rather continued to New York City with his family in December 1938, where they applied for permanent residency. The decision to move to America and become US citizens was due primarily to the racial laws in Italy.


Manhattan Project

Fermi arrived in New York City on 2 January 1939. He was immediately offered positions at five universities, and accepted one at
Columbia University Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...
, where he had already given summer lectures in 1936. He received the news that in December 1938, the German chemists Otto Hahn and Fritz Strassmann had detected the element
barium Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Th ...
after bombarding uranium with neutrons, which
Lise Meitner Elise Meitner ( , ; 7 November 1878 – 27 October 1968) was an Austrian-Swedish physicist who was one of those responsible for the discovery of the element protactinium and nuclear fission. While working at the Kaiser Wilhelm Institute on rad ...
and her nephew
Otto Frisch Otto Robert Frisch FRS (1 October 1904 – 22 September 1979) was an Austrian-born British physicist who worked on nuclear physics. With Lise Meitner he advanced the first theoretical explanation of nuclear fission (coining the term) and first ...
correctly interpreted as the result of
nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radio ...
. Frisch confirmed this experimentally on 13 January 1939. The news of Meitner and Frisch's interpretation of Hahn and Strassmann's discovery crossed the Atlantic with Niels Bohr, who was to lecture at
Princeton University Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...
. Isidor Isaac Rabi and Willis Lamb, two Columbia University physicists working at Princeton, found out about it and carried it back to Columbia. Rabi said he told Enrico Fermi, but Fermi later gave the credit to Lamb: Noddack was proven right after all. Fermi had dismissed the possibility of fission on the basis of his calculations, but he had not taken into account the
binding energy In physics and chemistry, binding energy is the smallest amount of energy required to remove a particle from a system of particles or to disassemble a system of particles into individual parts. In the former meaning the term is predominantly use ...
that would appear when a
nuclide A nuclide (or nucleide, from nucleus, also known as nuclear species) is a class of atoms characterized by their number of protons, ''Z'', their number of neutrons, ''N'', and their nuclear energy state. The word ''nuclide'' was coined by Truman ...
with an odd number of neutrons absorbed an extra neutron. For Fermi, the news came as a profound embarrassment, as the
transuranic elements The transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92, which is the atomic number of uranium. All of these elements are unstable and decay radioactively into other elements. ...
that he had partly been awarded the Nobel Prize for discovering had not been transuranic elements at all, but
fission products Nuclear fission products are the atomic fragments left after a large atomic nucleus undergoes nuclear fission. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons, the release ...
. He added a footnote to this effect to his Nobel Prize acceptance speech. The scientists at Columbia decided that they should try to detect the energy released in the nuclear fission of uranium when bombarded by neutrons. On 25 January 1939, in the basement of
Pupin Hall Pupin Physics Laboratories , also known as Pupin Hall, is home to the Columbia University Physics Department, physics and astronomy departments of Columbia University in New York City. The building is located on the south side of 120th Street (Man ...
at Columbia, an experimental team including Fermi conducted the first nuclear fission experiment in the United States. The other members of the team were
Herbert L. Anderson Herbert Lawrence Anderson (May 24, 1914 – July 16, 1988) was an American nuclear physicist who was Professor of Physics at the University of Chicago. He contributed to the Manhattan Project. He was also a member of the team which made the firs ...
,
Eugene T. Booth Eugene Theodore Booth, Jr. (28 September 1912 – 6 March 2004) was an American nuclear physicist. He was a member of the historic Columbia University team which made the first demonstration of nuclear fission in the United States. During the ...
,
John R. Dunning John Ray Dunning (September 24, 1907 – August 25, 1975) was an American physicist who played key roles in the Manhattan Project that developed the first atomic bombs. He specialized in neutron physics, and did pioneering work in gaseous diffusio ...
,
G. Norris Glasoe G. Norris Glasoe (29 October 1902 – May 1987) was an American nuclear physicist. He was a member of the Columbia University team which was the first in the United States to verify the European discovery of the nuclear fission of uranium via ne ...
, and
Francis G. Slack Francis Goddard Slack (November 1, 1897 – February 2, 1985) was an American physicist. He was a physics teacher, researcher, and administrator in academia who was renowned for placing equal emphasis on teaching and on research. Education Slack wa ...
. The next day, the Fifth Washington Conference on Theoretical Physics began in Washington, D.C. under the joint auspices of
George Washington University , mottoeng = "God is Our Trust" , established = , type = Private federally chartered research university , academic_affiliations = , endowment = $2.8 billion (2022) , preside ...
and the Carnegie Institution of Washington. There, the news on nuclear fission was spread even further, fostering many more experimental demonstrations. French scientists Hans von Halban, Lew Kowarski, and Frédéric Joliot-Curie had demonstrated that uranium bombarded by neutrons emitted more neutrons than it absorbed, suggesting the possibility of a chain reaction. Fermi and Anderson did so too a few weeks later. Leó Szilárd obtained of uranium oxide from Canadian
radium Radium is a chemical element with the symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rather t ...
producer Eldorado Gold Mines Limited, allowing Fermi and Anderson to conduct experiments with fission on a much larger scale. Fermi and Szilárd collaborated on a design of a device to achieve a self-sustaining nuclear reaction—a
nuclear reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nu ...
. Owing to the rate of absorption of neutrons by the hydrogen in water, it was unlikely that a self-sustaining reaction could be achieved with natural uranium and water as a
neutron moderator In nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, ideally without capturing any, leaving them as thermal neutrons with only minimal (thermal) kinetic energy. These thermal neutrons are immensely mo ...
. Fermi suggested, based on his work with neutrons, that the reaction could be achieved with uranium oxide blocks and
graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large ...
as a moderator instead of water. This would reduce the neutron capture rate, and in theory make a self-sustaining chain reaction possible. Szilárd came up with a workable design: a pile of uranium oxide blocks interspersed with graphite bricks. Szilárd, Anderson, and Fermi published a paper on "Neutron Production in Uranium". But their work habits and personalities were different, and Fermi had trouble working with Szilárd. Fermi was among the first to warn military leaders about the potential impact of nuclear energy, giving a lecture on the subject at the
Navy Department Navy Department or Department of the Navy may refer to: * United States Department of the Navy, * Navy Department (Ministry of Defence), in the United Kingdom, 1964-1997 * Confederate States Department of the Navy, 1861-1865 * Department of the Na ...
on 18 March 1939. The response fell short of what he had hoped for, although the Navy agreed to provide $1,500 towards further research at Columbia. Later that year, Szilárd, Eugene Wigner, and Edward Teller sent the letter signed by Einstein to US president
Franklin D. Roosevelt Franklin Delano Roosevelt (; ; January 30, 1882April 12, 1945), often referred to by his initials FDR, was an American politician and attorney who served as the 32nd president of the United States from 1933 until his death in 1945. As the ...
, warning that
Nazi Germany Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...
was likely to build an
atomic bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions (thermonuclear bomb), producing a nuclear explosion. Both bomb ...
. In response, Roosevelt formed the
Advisory Committee on Uranium The S-1 Executive Committee laid the groundwork for the Manhattan Project by initiating and coordinating the early research efforts in the United States, and liaising with the Tube Alloys Project in Britain. In the wake of the discovery of nucl ...
to investigate the matter. The Advisory Committee on Uranium provided money for Fermi to buy graphite, and he built a pile of graphite bricks on the seventh floor of the Pupin Hall laboratory. By August 1941, he had six tons of uranium oxide and thirty tons of graphite, which he used to build a still larger pile in Schermerhorn Hall at Columbia. The S-1 Section of the Office of Scientific Research and Development, as the Advisory Committee on Uranium was now known, met on 18 December 1941, with the US now engaged in
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, making its work urgent. Most of the effort sponsored by the committee had been directed at producing enriched uranium, but Committee member
Arthur Compton Arthur Holly Compton (September 10, 1892 – March 15, 1962) was an American physicist who won the Nobel Prize in Physics in 1927 for his 1923 discovery of the Compton effect, which demonstrated the particle nature of electromagnetic radia ...
determined that a feasible alternative was
plutonium Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibi ...
, which could be mass-produced in nuclear reactors by the end of 1944. He decided to concentrate the plutonium work at the
University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park neighborhood. The University of Chicago is consistently ranked among the b ...
. Fermi reluctantly moved, and his team became part of the new
Metallurgical Laboratory The Metallurgical Laboratory (or Met Lab) was a scientific laboratory at the University of Chicago that was established in February 1942 to study and use the newly discovered chemical element plutonium. It researched plutonium's chemistry and m ...
there. The possible results of a self-sustaining nuclear reaction were unknown, so it seemed inadvisable to build the first nuclear reactor on the University of Chicago campus in the middle of the city. Compton found a location in the Argonne Woods Forest Preserve, about from Chicago.
Stone & Webster Stone & Webster was an American engineering services company based in Stoughton, Massachusetts. It was founded as an electrical testing lab and consulting firm by electrical engineers Charles A. Stone and Edwin S. Webster in 1889. In the early ...
was contracted to develop the site, but the work was halted by an industrial dispute. Fermi then persuaded Compton that he could build the reactor in the squash court under the stands of the University of Chicago's
Stagg Field Amos Alonzo Stagg Field is the name of two successive football fields for the University of Chicago. Beyond sports, the first Stagg Field (1893–1957) is remembered for its role in a landmark scientific achievement of Enrico Fermi and the Metall ...
. Construction of the pile began on 6 November 1942, and
Chicago Pile-1 Chicago Pile-1 (CP-1) was the world's first artificial nuclear reactor. On 2 December 1942, the first human-made self-sustaining nuclear chain reaction was initiated in CP-1, during an experiment led by Enrico Fermi. The secret development of t ...
went
critical Critical or Critically may refer to: *Critical, or critical but stable, medical states **Critical, or intensive care medicine *Critical juncture, a discontinuous change studied in the social sciences. *Critical Software, a company specializing in ...
on 2 December. The shape of the pile was intended to be roughly spherical, but as work proceeded Fermi calculated that criticality could be achieved without finishing the entire pile as planned. This experiment was a landmark in the quest for energy, and it was typical of Fermi's approach. Every step was carefully planned, every calculation was meticulously done. When the first self-sustained nuclear chain reaction was achieved, Compton made a coded phone call to
James B. Conant James Bryant Conant (March 26, 1893 – February 11, 1978) was an American chemist, a transformative President of Harvard University, and the first U.S. Ambassador to West Germany. Conant obtained a Ph.D. in Chemistry from Harvard in 1916. ...
, the chairman of the National Defense Research Committee. To continue the research where it would not pose a public health hazard, the reactor was disassembled and moved to the Argonne Woods site. There Fermi directed experiments on nuclear reactions, reveling in the opportunities provided by the reactor's abundant production of free neutrons. The laboratory soon branched out from physics and engineering into using the reactor for biological and medical research. Initially, Argonne was run by Fermi as part of the University of Chicago, but it became a separate entity with Fermi as its director in May 1944. When the air-cooled X-10 Graphite Reactor at Oak Ridge went critical on 4 November 1943, Fermi was on hand just in case something went wrong. The technicians woke him early so that he could see it happen. Getting X-10 operational was another milestone in the plutonium project. It provided data on reactor design, training for
DuPont DuPont de Nemours, Inc., commonly shortened to DuPont, is an American multinational chemical company first formed in 1802 by French-American chemist and industrialist Éleuthère Irénée du Pont de Nemours. The company played a major role in ...
staff in reactor operation, and produced the first small quantities of reactor-bred plutonium. Fermi became an American citizen in July 1944, the earliest date the law allowed. In September 1944, Fermi inserted the first uranium fuel slug into the
B Reactor The B Reactor at the Hanford Site, near Richland, Washington, was the first large-scale nuclear reactor ever built. The project was a key part of the Manhattan Project, the United States nuclear weapons development program during World War II. I ...
at the Hanford Site, the production reactor designed to breed plutonium in large quantities. Like X-10, it had been designed by Fermi's team at the Metallurgical Laboratory and built by DuPont, but it was much larger and was water-cooled. Over the next few days, 838 tubes were loaded, and the reactor went critical. Shortly after midnight on 27 September, the operators began to withdraw the
control rod Control rods are used in nuclear reactors to control the rate of fission of the nuclear fuel – uranium or plutonium. Their compositions include chemical elements such as boron, cadmium, silver, hafnium, or indium, that are capable of absorbing ...
s to initiate production. At first, all appeared to be well, but around 03:00, the power level started to drop and by 06:30 the reactor had shut down completely. The Army and DuPont turned to Fermi's team for answers. The cooling water was investigated to see if there was a leak or contamination. The next day the reactor suddenly started up again, only to shut down once more a few hours later. The problem was traced to neutron poisoning from
xenon-135 Xenon-135 (135Xe) is an unstable isotope of xenon with a half-life of about 9.2 hours. 135Xe is a fission product of uranium and it is the most powerful known neutron-absorbing nuclear poison (2 million barns; up to 3 million barns under reactor c ...
or Xe-135, a fission product with a half-life of 9.1 to 9.4 hours. Fermi and John Wheeler both deduced that Xe-135 was responsible for absorbing neutrons in the reactor, thereby sabotaging the fission process. Fermi was recommended by colleague Emilio Segrè to ask
Chien-Shiung Wu ) , spouse = , residence = , nationality = ChineseAmerican , field = Physics , work_institutions = Institute of Physics, Academia SinicaUniversity of California at BerkeleySmith CollegePrinceton UniversityColumbia UniversityZhejiang Unive ...
, as she prepared a printed draft on this topic to be published by the
Physical Review ''Physical Review'' is a peer-reviewed scientific journal established in 1893 by Edward Nichols. It publishes original research as well as scientific and literature reviews on all aspects of physics. It is published by the American Physical S ...
. Upon reading the draft, Fermi and the scientists confirmed their suspicions: Xe-135 indeed absorbed neutrons, in fact it had a huge neutron cross-section. DuPont had deviated from the Metallurgical Laboratory's original design in which the reactor had 1,500 tubes arranged in a circle, and had added 504 tubes to fill in the corners. The scientists had originally considered this over-engineering a waste of time and money, but Fermi realized that if all 2,004 tubes were loaded, the reactor could reach the required power level and efficiently produce plutonium. In April 1943, Fermi raised with
Robert Oppenheimer J. Robert Oppenheimer (; April 22, 1904 – February 18, 1967) was an American theoretical physicist. A professor of physics at the University of California, Berkeley, Oppenheimer was the wartime head of the Los Alamos Laboratory and is often ...
the possibility of using the radioactive byproducts from enrichment to contaminate the German food supply. The background was fear that the German atomic bomb project was already at an advanced stage, and Fermi was also skeptical at the time that an atomic bomb could be developed quickly enough. Oppenheimer discussed the "promising" proposal with Edward Teller, who suggested the use of strontium-90. James B. Conant and Leslie Groves were also briefed, but Oppenheimer wanted to proceed with the plan only if enough food could be contaminated with the weapon to kill half a million people. In mid-1944, Oppenheimer persuaded Fermi to join his Project Y at
Los Alamos, New Mexico Los Alamos is an census-designated place in Los Alamos County, New Mexico, United States, that is recognized as the development and creation place of the atomic bomb—the primary objective of the Manhattan Project by Los Alamos National Labora ...
. Arriving in September, Fermi was appointed an associate director of the laboratory, with broad responsibility for nuclear and theoretical physics, and was placed in charge of F Division, which was named after him. F Division had four branches: F-1 Super and General Theory under Teller, which investigated the "Super" (thermonuclear) bomb; F-2 Water Boiler under L. D. P. King, which looked after the "water boiler" aqueous homogeneous research reactor; F-3 Super Experimentation under
Egon Bretscher Egon Bretscher CBE (1901–1973) was a Swiss-born British chemist and nuclear physicist and Head of the Nuclear Physics Division from 1948 to 1966 at the Atomic Energy Research Establishment, also known as Harwell Laboratory, in Harwell, United K ...
; and F-4 Fission Studies under Anderson. Fermi observed the Trinity test on 16 July 1945 and conducted an experiment to estimate the bomb's yield by dropping strips of paper into the blast wave. He paced off the distance they were blown by the explosion, and calculated the yield as ten kilotons of TNT; the actual yield was about 18.6 kilotons. Along with Oppenheimer, Compton, and
Ernest Lawrence Ernest Orlando Lawrence (August 8, 1901 – August 27, 1958) was an American nuclear physicist and winner of the Nobel Prize in Physics in 1939 for his invention of the cyclotron. He is known for his work on uranium-isotope separation f ...
, Fermi was part of the scientific panel that advised the
Interim Committee The Interim Committee was a secret high-level group created in May 1945 by United States Secretary of War, Henry L. Stimson at the urging of leaders of the Manhattan Project and with the approval of President Harry S. Truman to advise on m ...
on target selection. The panel agreed with the committee that atomic bombs would be used without warning against an industrial target. Like others at the Los Alamos Laboratory, Fermi found out about the
atomic bombings of Hiroshima and Nagasaki The United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August 1945, respectively. The two bombings killed between 129,000 and 226,000 people, most of whom were civilians, and remain the onl ...
from the public address system in the technical area. Fermi did not believe that atomic bombs would deter nations from starting wars, nor did he think that the time was ripe for
world government World government is the concept of a single political authority with jurisdiction over all humanity. It is conceived in a variety of forms, from tyrannical to democratic, which reflects its wide array of proponents and detractors. A world gove ...
. He therefore did not join the
Association of Los Alamos Scientists The Association of Los Alamos Scientists (ALAS) was founded on August 30, 1945, by a group of scientists, who had worked on the development of the atomic bomb at the Los Alamos Laboratory, a division of the Manhattan Project. Purpose The purpo ...
.


Postwar work

Fermi became the Charles H. Swift Distinguished Professor of Physics at the University of Chicago on 1 July 1945, although he did not depart the Los Alamos Laboratory with his family until 31 December 1945. He was elected a member of the US National Academy of Sciences in 1945. The Metallurgical Laboratory became the
Argonne National Laboratory Argonne National Laboratory is a science and engineering research United States Department of Energy National Labs, national laboratory operated by University of Chicago, UChicago Argonne LLC for the United States Department of Energy. The facil ...
on 1 July 1946, the first of the national laboratories established by the Manhattan Project. The short distance between Chicago and Argonne allowed Fermi to work at both places. At Argonne he continued experimental physics, investigating neutron scattering with
Leona Marshall Leona Harriet Woods (August 9, 1919 – November 10, 1986), later known as Leona Woods Marshall and Leona Woods Marshall Libby, was an American physicist who helped build the first nuclear reactor and the first atomic bomb. At age 23, sh ...
. He also discussed theoretical physics with
Maria Mayer Maria Goeppert Mayer (; June 28, 1906 – February 20, 1972) was a German-born American theoretical physicist, and Nobel laureate in Physics for proposing the nuclear shell model of the atomic nucleus. She was the second woman to win a Nobel Pri ...
, helping her develop insights into spin–orbit coupling that would lead to her receiving the Nobel Prize. The Manhattan Project was replaced by the Atomic Energy Commission (AEC) on 1 January 1947. Fermi served on the AEC General Advisory Committee, an influential scientific committee chaired by Robert Oppenheimer. He also liked to spend a few weeks of each year at the Los Alamos National Laboratory, where he collaborated with
Nicholas Metropolis Nicholas Constantine Metropolis (Greek: ; June 11, 1915 – October 17, 1999) was a Greek-American physicist. Metropolis received his BSc (1937) and PhD in physics (1941, with Robert Mulliken) at the University of Chicago. Shortly afterwards, ...
, and with
John von Neumann John von Neumann (; hu, Neumann János Lajos, ; December 28, 1903 – February 8, 1957) was a Hungarian-American mathematician, physicist, computer scientist, engineer and polymath. He was regarded as having perhaps the widest cove ...
on Rayleigh–Taylor instability, the science of what occurs at the border between two fluids of different densities. After the detonation of the first Soviet
fission bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions (thermonuclear bomb), producing a nuclear explosion. Both bomb ...
in August 1949, Fermi, along with Isidor Rabi, wrote a strongly worded report for the committee, opposing the development of a hydrogen bomb on moral and technical grounds. Nonetheless, Fermi continued to participate in work on the hydrogen bomb at Los Alamos as a consultant. Along with
Stanislaw Ulam Stanisław Marcin Ulam (; 13 April 1909 – 13 May 1984) was a Polish-American scientist in the fields of mathematics and nuclear physics. He participated in the Manhattan Project, originated the Teller–Ulam design of thermonuclear weapon ...
, he calculated that not only would the amount of tritium needed for Teller's model of a thermonuclear weapon be prohibitive, but a
fusion reaction Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons). The difference in mass between the reactants and products is manifeste ...
could still not be assured to propagate even with this large quantity of tritium. Fermi was among the scientists who testified on Oppenheimer's behalf at the
Oppenheimer security hearing The Oppenheimer security hearing was a 1954 proceeding by the United States Atomic Energy Commission (AEC) that explored the background, actions, and associations of J. Robert Oppenheimer, the American scientist who had headed the Los Alamos Lab ...
in 1954 that resulted in denial of Oppenheimer's security clearance. In his later years, Fermi continued teaching at the University of Chicago, where he was a founder of what later became the Enrico Fermi Institute. His PhD students in the postwar period included
Owen Chamberlain Owen Chamberlain (July 10, 1920 – February 28, 2006) was an American physicist who shared with Emilio Segrè the Nobel Prize in Physics for the discovery of the antiproton, a sub-atomic antiparticle. Biography Born in San Francisco, Cali ...
,
Geoffrey Chew Geoffrey Foucar Chew (; June 5, 1924 – April 12, 2019) was an American theoretical physicist. He is known for his bootstrap theory of strong interactions. Life Chew worked as a professor of physics at the UC Berkeley since 1957 and was an e ...
, Jerome Friedman, Marvin Goldberger,
Tsung-Dao Lee Tsung-Dao Lee (; born November 24, 1926) is a Chinese-American physicist, known for his work on parity violation, the Lee–Yang theorem, particle physics, relativistic heavy ion (RHIC) physics, nontopological solitons, and soliton star ...
, Arthur Rosenfeld and Sam Treiman. including the Nobel Lecture, 12 December 1938 ''Artificial Radioactivity Produced by Neutron Bombardment'' Jack Steinberger was a graduate student, and Mildred Dresselhaus was highly influenced by Fermi during the year she overlapped with him as a PhD student. Fermi conducted important research in particle physics, especially related to pions and
muon A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of , but with a much greater mass. It is classified as a lepton. As wi ...
s. He made the first predictions of pion- nucleon resonance, relying on statistical methods, since he reasoned that exact answers were not required when the theory was wrong anyway. In a paper coauthored with
Chen Ning Yang Yang Chen-Ning or Chen-Ning Yang (; born 1 October 1922), also known as C. N. Yang or by the English name Frank Yang, is a Chinese theoretical physicist who made significant contributions to statistical mechanics, integrable systems, gauge the ...
, he speculated that pions might actually be composite particles. The idea was elaborated by Shoichi Sakata. It has since been supplanted by the
quark model In particle physics, the quark model is a classification scheme for hadrons in terms of their valence quarks—the quarks and antiquarks which give rise to the quantum numbers of the hadrons. The quark model underlies "flavor SU(3)", or the E ...
, in which the pion is made up of quarks, which completed Fermi's model, and vindicated his approach. Fermi wrote a paper "On the Origin of
Cosmic Radiation Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...
" in which he proposed that cosmic rays arose through material being accelerated by magnetic fields in interstellar space, which led to a difference of opinion with Teller. Fermi examined the issues surrounding magnetic fields in the arms of a
spiral galaxy Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''Fermi paradox": the contradiction between the presumed probability of the existence of extraterrestrial life and the fact that contact has not been made. Toward the end of his life, Fermi questioned his faith in society at large to make wise choices about nuclear technology. He said:


Death

Fermi underwent what was called an "exploratory" operation in Billings Memorial Hospital in October 1954, after which he returned home. Fifty days later he died of inoperable
stomach cancer Stomach cancer, also known as gastric cancer, is a cancer that develops from the lining of the stomach. Most cases of stomach cancers are gastric carcinomas, which can be divided into a number of subtypes, including gastric adenocarcinomas. Lymph ...
in his home in Chicago. He was 53. Fermi suspected working near the nuclear pile involved great risk but he pressed on because the benefits outweighed the risks to his personal safety. Two of his graduate student assistants working near the pile also died of cancer. A memorial service was held at the University of Chicago chapel, where colleagues
Samuel K. Allison Samuel King Allison (November 13, 1900 – September 15, 1965) was an American physicist, most notable for his role in the Manhattan Project, for which he was awarded the Medal for Merit. He was director of the Metallurgical Laboratory from 1943 ...
, Emilio Segrè, and Herbert L. Anderson spoke to mourn the loss of one of the world's "most brilliant and productive physicists." His body was interred at
Oak Woods Cemetery Oak Woods Cemetery is a large lawn cemetery in Chicago, Illinois. Located at 1035 E. 67th Street, in the Greater Grand Crossing area of Chicago's South Side. Established on February 12, 1853, it covers . Oak Woods is the final resting place o ...
where a private graveside service for the immediate family took place presided by a Lutheran chaplain.


Impact and legacy


Legacy

Fermi received numerous awards in recognition of his achievements, including the Matteucci Medal in 1926, the Nobel Prize for Physics in 1938, the
Hughes Medal The Hughes Medal is awarded by the Royal Society of London "in recognition of an original discovery in the physical sciences, particularly electricity and magnetism or their applications". Named after David E. Hughes, the medal is awarded with ...
in 1942, the
Franklin Medal The Franklin Medal was a science award presented from 1915 until 1997 by the Franklin Institute located in Philadelphia, Pennsylvania, U.S. It was founded in 1914 by Samuel Insull Samuel Insull (November 11, 1859 – July 16, 1938) was a Bri ...
in 1947, and the Rumford Prize in 1953. He was awarded the
Medal for Merit The Medal for Merit was, during the period it was awarded, the highest civilian decoration of the United States. It was awarded by the President of the United States to civilians who "distinguished themselves by exceptionally meritorious conduct i ...
in 1946 for his contribution to the Manhattan Project. Fermi was elected a Foreign Member of the Royal Society (FRS) in 1950. The
Basilica of Santa Croce The (Italian for 'Basilica of the Holy Cross') is the principal Franciscan church in Florence, Italy, and a minor basilica of the Roman Catholic Church. It is situated on the Piazza di Santa Croce, about 800 meters south-east of the Duomo. The ...
,
Florence Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilancio demografico an ...
, known as the ''Temple of Italian Glories'' for its many graves of artists, scientists and prominent figures in Italian history, has a plaque commemorating Fermi. In 1999, ''
Time Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to ...
'' named Fermi on its list of the top 100 persons of the twentieth century. Fermi was widely regarded as an unusual case of a 20th-century physicist who excelled both theoretically and experimentally. Chemist and novelist C. P. Snow wrote, "if Fermi had been born a few years earlier, one could well imagine him discovering Rutherford's atomic nucleus, and then developing Bohr's theory of the hydrogen atom. If this sounds like hyperbole, anything about Fermi is likely to sound like hyperbole". Fermi was known as an inspiring teacher and was noted for his attention to detail, simplicity, and careful preparation of his lectures. Later, his lecture notes were transcribed into books. His papers and notebooks are today in the University of Chicago. Victor Weisskopf noted how Fermi "always managed to find the simplest and most direct approach, with the minimum of complication and sophistication." He disliked complicated theories, and while he had great mathematical ability, he would never use it when the job could be done much more simply. He was famous for getting quick and accurate answers to problems that would stump other people. Later on, his method of getting approximate and quick answers through back-of-the-envelope calculations became informally known as the "
Fermi method In physics or engineering education, a Fermi problem, Fermi quiz, Fermi question, Fermi estimate, order-of-magnitude problem, order-of-magnitude estimate, or order estimation is an estimation problem designed to teach dimensional analysis or a ...
", and is widely taught. Fermi was fond of pointing out that when
Alessandro Volta Alessandro Giuseppe Antonio Anastasio Volta (, ; 18 February 1745 – 5 March 1827) was an Italian physicist, chemist and lay Catholic who was a pioneer of electricity and power who is credited as the inventor of the electric battery and the ...
was working in his laboratory, Volta had no idea where the study of electricity would lead. Fermi is generally remembered for his work on nuclear power and nuclear weapons, especially the creation of the first nuclear reactor, and the development of the first atomic and hydrogen bombs. His scientific work has stood the test of time. This includes his theory of beta decay, his work with non-linear systems, his discovery of the effects of slow neutrons, his study of pion-nucleon collisions, and his Fermi–Dirac statistics. His speculation that a pion was not a fundamental particle pointed the way towards the study of
quark A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. All commonly o ...
s and
lepton In particle physics, a lepton is an elementary particle of half-integer spin ( spin ) that does not undergo strong interactions. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons or muons), and neutr ...
s.


Things named after Fermi

Many things bear Fermi's name. These include the
Fermilab Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a United States Department of Energy national laboratory specializing in high-energy particle physics. Since 2007, Fermilab has been operat ...
particle accelerator and physics lab in
Batavia, Illinois Batavia () is a city mainly in Kane County and partly in DuPage County in the U.S. state of Illinois. Located in the Chicago metropolitan area, it was founded in 1833 and is the oldest city in Kane County. Per the 2020 census, the population w ...
, which was renamed in his honor in 1974, and the Fermi Gamma-ray Space Telescope, which was named after him in 2008, in recognition of his work on cosmic rays. Three nuclear reactor installations have been named after him: the
Fermi 1 Fermi 1 was the United States' only demonstration-scale breeder reactor, built during the 1950s at the Enrico Fermi Nuclear Generating Station on the western shore of Lake Erie south of Detroit, Michigan. It used the sodium-cooled fast reactor cyc ...
and
Fermi 2 The Enrico Fermi Nuclear Generating Station is a nuclear power plant on the shore of Lake Erie near Monroe, in Frenchtown Charter Township, Michigan on approximately . All units of the plant are operated by the DTE Energy Electric Company and own ...
nuclear power plants in
Newport, Michigan Newport is an unincorporated community in Monroe County in the U.S. state of Michigan. The community is located within Berlin Charter Township. As an unincorporated community, Newport has no legally defined boundaries or population statistics o ...
, the
Enrico Fermi Nuclear Power Plant The Enrico Fermi Nuclear Generating Station is a nuclear power plant on the shore of Lake Erie near Monroe, in Frenchtown Charter Township, Michigan on approximately . All units of the plant are operated by the DTE Energy Electric Company and ow ...
at
Trino Vercellese Trino ( pms, Trin) is a ''comune'' (municipality) in the Province of Vercelli in the Italian region Piedmont, located about northeast of Turin and about southwest of Vercelli, at the foot of the Montferrat hills. Trino borders the following mun ...
in Italy, and the RA-1 Enrico Fermi research reactor in
Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
. A synthetic element isolated from the debris of the 1952
Ivy Mike Ivy Mike was the codename given to the first full-scale test of a thermonuclear device, in which part of the explosive yield comes from nuclear fusion. Ivy Mike was detonated on November 1, 1952, by the United States on the island of Elugelab in ...
nuclear test was named
fermium Fermium is a synthetic element with the symbol Fm and atomic number 100. It is an actinide and the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic qua ...
, in honor of Fermi's contributions to the scientific community. This makes him one of 16 scientists who have elements named after them. Since 1956, the United States Atomic Energy Commission has named its highest honor, the
Fermi Award The Enrico Fermi Award is a scientific award conferred by the President of the United States. It is awarded to honor scientists of international stature for their lifetime achievement in the development, use, or production of energy. It was establ ...
, after him. Recipients of the award have included Otto Hahn, Robert Oppenheimer, Edward Teller and Hans Bethe.


Publications

* * * * * * (with Edoardo Amaldi) * * For a full list of his papers, see pages 75–78 in ref.


Patents

* * * * * * * * * * * * * *


Notes


References

* * * * * * * * * * * * * * * * * * * * * * * * * * * * *


External links


"To Fermi – with Love – Part 1"
Voices of the Manhattan Project 1971 Radio Segment
"The First Reactor: 40th Anniversary Commemorative Edition"
United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United Stat ...
, (December 1982).
Nobel prize page for the 1938 physics' prize

The Story of the First Pile

Enrico Fermi's Case File
at The Franklin Institute with information about his contributions to theoretical and experimental physics.
"Remembering Enrico Fermi"
Session J1. APS April Meeting 2010, American Physical Society.

by Richard Rhodes 29 March 1999
Fermi's stay with Ehrenfest in Leiden
{{DEFAULTSORT:Fermi, Enrico 1901 births 1954 deaths American nuclear physicists Italian nuclear physicists Experimental physicists Theoretical physicists Quantum physicists American relativity theorists Thermodynamicists 20th-century American physicists Manhattan Project people 20th-century Italian inventors Nobel laureates in Physics Italian Nobel laureates Medal for Merit recipients Members of the United States National Academy of Sciences Foreign Members of the Royal Society Corresponding Members of the USSR Academy of Sciences Members of the Royal Academy of Italy Members of the Lincean Academy Fellows of the American Physical Society Italian emigrants to the United States Monte Carlo methodologists University of Chicago faculty Columbia University faculty University of Göttingen faculty Sapienza University of Rome faculty University of Pisa alumni American agnostics Italian agnostics Italian Freemasons People from Leonia, New Jersey Scientists from Rome Deaths from stomach cancer Deaths from cancer in Illinois Burials in Illinois Italian exiles Naturalized citizens of the United States Recipients of the Matteucci Medal Winners of the Max Planck Medal Presidents of the American Physical Society