Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian (later
naturalized 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 fr ...
, the
Chicago Pile-1. 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 reacti ...
" 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. 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
Induced radioactivity, also called artificial radioactivity or man-made radioactivity, is the process of using radiation to make a previously stable material radioactive. The husband and wife team of Irène Joliot-Curie and Frédéric Joliot-Curi ...
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,
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 ...
, 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 ...
formulated his
exclusion principle in 1925, Fermi followed with a paper in which he applied the principle to an
ideal gas
An ideal gas is a theoretical gas composed of many randomly moving point particles that are not subject to interparticle interactions. The ideal gas concept is useful because it obeys the ideal gas law, a simplified equation of state, and is a ...
, employing a statistical formulation now known as
Fermi–Dirac statistics. Today, particles that obey the exclusion principle are called "
fermions". 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 ...
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. Fermi took up this idea, developing a model that incorporated the postulated particle, which he named the "
neutrino
A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass ...
". 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
In nuclear physics and particle physics, the weak interaction, which is also often called the weak force or weak nuclear force, is one of the four known fundamental interactions, with the others being electromagnetism, the strong interaction ...
, described one of the four
fundamental interaction
In physics, the fundamental interactions, also known as fundamental forces, are the interactions that do not appear to be reducible to more basic interactions. There are four fundamental interactions known to exist: the gravitational and electro ...
s 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 neutron
The neutron detection temperature, also called the neutron energy, indicates a free neutron's kinetic energy, usually given in electron volts. The term ''temperature'' is used, since hot, thermal and cold neutrons are moderated in a medium with ...
s 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 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 ...
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 product
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 ...
s.
Fermi left Italy in 1938 to escape new
Italian racial laws that affected his Jewish wife,
Laura Capon. 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 university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...
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. He was on hand when the
X-10 Graphite Reactor at
Oak Ridge, Tennessee, 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
The Hanford Site is a decommissioned nuclear production complex operated by the United States federal government on the Columbia River in Benton County in the U.S. state of Washington. The site has been known by many names, including SiteW a ...
did so the next year. At
Los Alamos, he headed F Division, part of which worked on
Edward Teller
Edward Teller ( hu, Teller Ede; January 15, 1908 – September 9, 2003) was a Hungarian-American theoretical physicist who is known colloquially as "the father of the hydrogen bomb" (see the Teller–Ulam design), although he did not care for ...
'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" bomb. He was present at the
Trinity test
Trinity was the code name of the first detonation of a nuclear weapon. It was conducted by the United States Army at 5:29 a.m. on July 16, 1945, as part of the Manhattan Project. The test was conducted in the Jornada del Muerto desert abo ...
on 16 July 1945, where he used his
Fermi method to estimate the bomb's yield.
After the war, Fermi served under
J. 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 oft ...
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
Hearing, or auditory perception, is the ability to perceive sounds through an organ, such as an ear, by detecting vibrations as periodic changes in the pressure of a surrounding medium. The academic field concerned with hearing is audit ...
that resulted in the denial of Oppenheimer's security clearance. Fermi did important work in particle physics, especially related to
pion
In particle physics, a pion (or a pi meson, denoted with the Greek letter pi: ) is any of three subatomic particles: , , and . Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more gene ...
s and
muons, 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
__NOTOC__
The Institute for Nuclear Studies was founded September 1945 as part of the University of Chicago with Samuel King Allison as director. On November 20, 1955, it was renamed The Enrico Fermi Institute for Nuclear Studies. The name was s ...
, the
Fermi National Accelerator Laboratory (Fermilab), the
Fermi Gamma-ray Space Telescope
The Fermi Gamma-ray Space Telescope (FGST, also FGRST), formerly called the Gamma-ray Large Area Space Telescope (GLAST), is a space observatory being used to perform gamma-ray astronomy observations from low Earth orbit. Its main instrument is ...
, 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 birthplace plaque](https://upload.wikimedia.org/wikipedia/commons/4/4a/Enrico_Fermi_birthplace_plaque.jpg)
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 nurse
A wet nurse is a woman who breastfeeds and cares for another's child. Wet nurses are employed if the mother dies, or if she is unable or chooses not to nurse the child herself. Wet-nursed children may be known as "milk-siblings", and in some cu ...
d, 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 let ...
in accordance with his grandparents' wishes, his family was not particularly religious; Enrico was an
agnostic 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 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 wire winding to generate for ...
s and playing with electrical and mechanical toys. Giulio died during an operation on a throat
abscess 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 nort ...
Fermi found a physics book, the 900-page ''Elementorum physicae mathematicae''. Written in Latin by
Jesuit Father , a professor at the
Collegio Romano
The Roman College ( la, Collegium Romanum, it, Collegio Romano) was a school established by St. Ignatius of Loyola in 1551, just 11 years after he founded the Society of Jesus (Jesuits). It quickly grew to include classes from elementary school t ...
, it presented
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 classi ...
,
astronomy
Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, g ...
,
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, ultrav ...
, and
acoustics as they were understood at the time of its 1840 publication. With a scientifically inclined friend,
Enrico Persico, Fermi pursued projects such as building
gyroscopes 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 quanti ...
.
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
In mathematics, projective geometry is the study of geometric properties that are invariant with respect to projective transformations. This means that, compared to elementary Euclidean geometry, projective geometry has a different setting, ...
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
![Enrico Fermi giovane](https://upload.wikimedia.org/wikipedia/commons/3/3c/Enrico_Fermi_giovane.jpg)
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
**Ge ...
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'' in
Pisa. Amidei felt that the Scuola would provide better conditions for Fermi's development than the
Sapienza University of Rome
The Sapienza University of Rome ( it, Sapienza – Università di Roma), also called simply Sapienza or the University of Rome, and formally the Università degli Studi di Roma "La Sapienza", is a public research university located in Rome, Ita ...
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 to derive and solve the
partial differential equation 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; the two became close friends and collaborators. Fermi was advised by
Luigi Puccianti, 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
In mathematics, tensor calculus, tensor analysis, or Ricci calculus is an extension of vector calculus to tensor fields (tensors that may vary over a manifold, e.g. in spacetime).
Developed by Gregorio Ricci-Curbastro and his student Tullio Levi ...
, 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 chemistr ...
, and
atomic physics.
In September 1920, Fermi was admitted to the Physics department. Since there were only three students in the department—Fermi, Rasetti, and
Nello Carrara—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''. 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 eleme ...
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 tensor ...
—a mathematical construct commonly used to describe something moving and changing in three-dimensional space. In classical mechanics, mass is a
scalar 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/c
2, 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/c
2. 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 c ...
" (') to the Italian journal '. In this article he examined the
Principle of Equivalence, and introduced the so-called "
Fermi coordinates". 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'', it was the three-dimensional space of Euclidean geometry, but in modern mathematics there are Euclidean ...
.
![World line2](https://upload.wikimedia.org/wikipedia/commons/9/90/World_line2.svg)
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
In Italy, the ''laurea'' is the main post-secondary academic degree. The name originally referred literally to the laurel wreath, since ancient times a sign of honor and now worn by Italian students right after their official graduation ceremony ...
at the unusually young age of 20. The thesis was on
X-ray diffraction 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. 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
August Kopff (February 5, 1882 – April 25, 1960) was a German astronomer and discoverer of several comets and asteroids.
Kopff studied and worked in Heidelberg, getting his PhD there in 1906 and he then joined the Humboldt University of Berli ...
in 1923, Fermi was the first to point out that hidden inside the
Einstein equation () 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
A Masonic lodge, often termed a private lodge or constituent lodge, is the basic organisational unit of Freemasonry. It is also commonly used as a term for a building in which such a unit meets. Every new lodge must be warranted or chartered ...
"Adriano Lemmi" of the
Grand Orient of Italy.
In 1923–1924, Fermi spent a semester studying under
Max Born 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 serie ...
and
Pascual Jordan
Ernst Pascual Jordan (; 18 October 1902 – 31 July 1980) was a German theoretical and mathematical physicist who made significant contributions to quantum mechanics and quantum field theory. He contributed much to the mathematical form of matri ...
. 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 wi ...
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 a ...
from September to December 1924 on a fellowship from the
Rockefeller Foundation obtained through the intercession of the mathematician
Vito Volterra
Vito Volterra (, ; 3 May 1860 – 11 October 1940) was an Italian mathematician and physicist, known for his contributions to mathematical biology and integral equations, being one of the founders of functional analysis.
Biography
Born in An ...
. Here Fermi met
Hendrik Lorentz 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
Samuel Abraham Goudsmit (July 11, 1902 – December 4, 1978) was a Dutch-American physicist famous for jointly proposing the concept of electron spin with George Eugene Uhlenbeck in 1925.
Life and career
Goudsmit was born in The Hague, Nethe ...
and
Jan Tinbergen
Jan Tinbergen (; ; 12 April 19039 June 1994) was a Dutch economist who was awarded the first Nobel Memorial Prize in Economic Sciences in 1969, which he shared with Ragnar Frisch for having developed and applied dynamic models for the analysis o ...
. From January 1925 to late 1926, Fermi taught
mathematical physics
Mathematical physics refers to the development of 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 the developme ...
and
theoretical mechanics
Mechanics (from Ancient Greek: μηχανική, ''mēkhanikḗ'', "of machines") is the area of mathematics and physics concerned with the relationships between force, matter, and motion among physical objects. Forces applied to objects re ...
at the
University of Florence
The University of Florence (Italian: ''Università degli Studi di Firenze'', UniFI) is an Italian public research university located in Florence, Italy. It comprises 12 schools and has around 50,000 students enrolled.
History
The first universi ...
, 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. 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 ...
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 of many
identical particles
In quantum mechanics, identical particles (also called indistinguishable or indiscernible particles) are particles that cannot be distinguished from one another, even in principle. Species of identical particles include, but are not limited to, ...
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
In quantum statistics, Bose–Einstein statistics (B–E statistics) describes one of two possible ways in which a collection of non-interacting, indistinguishable particles may occupy a set of available discrete energy states at thermodynamic ...
. Accordingly, it is now known as
Fermi–Dirac statistics. After Dirac, particles that obey the exclusion principle are today called "
fermions", while those that do not are called "
boson
In particle physics, a boson ( ) is a subatomic particle whose spin quantum number has an integer value (0,1,2 ...). Bosons form one of the two fundamental classes of subatomic particle, the other being fermions, which have odd half-integer spi ...
s".
Professor in Rome
![Ragazzi di via Panisperna cropped](https://upload.wikimedia.org/wikipedia/commons/4/4d/Ragazzi_di_via_Panisperna_cropped.jpg)
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 ...
. 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
Orso Mario Corbino (30 April 1876, Augusta – 23 January 1937, Rome) was an Italian physicist and politician. His younger brother was Epicarmo Corbino.
He served as the minister for education in 1921 and as the minister for economy in 1921. H ...
, who was the university's professor of experimental physics, the Director of the Institute of Physics, and a member of
Benito Mussolini'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, and Corbino helped Fermi recruit his team, which was soon joined by notable students such as
Edoardo Amaldi
Edoardo Amaldi (5 September 1908 – 5 December 1989) was an Italian physicist. He coined the term "neutrino" in conversations with Enrico Fermi distinguishing it from the heavier "neutron". He has been described as "one of the leading nuclear ...
,
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 and ...
,
Ettore Majorana
Ettore Majorana (,, uploaded 19 April 2013, retrieved 14 December 2019 ; born on 5 August 1906 – possibly dying after 1959) was an Italian theoretical physicist who worked on neutrino masses. On 25 March 1938, he disappeared under mysteri ...
and
Emilio Segrè
Emilio Gino Segrè (1 February 1905 – 22 April 1989) was an Italian-American physicist and Nobel laureate, who discovered the elements technetium and astatine, and the antiproton, a subatomic antiparticle, for which he was awarded the Nobe ...
, and by Franco Rasetti, whom Fermi had appointed as his assistant. They soon nicknamed the "
Via Panisperna boys
Via Panisperna boys (Italian: ''I ragazzi di Via Panisperna'') is the name given to a group of young Italian scientists led by Enrico Fermi, who worked at the Royal Physics Institute of the University of Rome La Sapienza. In 1934 they made the ...
" after the street where the Institute of Physics was located.
Fermi married
Laura Capon, 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
The Royal Academy of Italy ( it, Reale Accademia d'Italia, italic=no) was a short-lived Italian academy of the Fascist period. It was created on 7 January 1926 by royal decree,See reference . but was not inaugurated until 28 October 1929. It was e ...
by Mussolini, and on 27 April he joined the
Fascist Party. He later opposed Fascism when the 1938
racial laws 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) i ...
. 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
Hans Albrecht Bethe (; July 2, 1906 – March 6, 2005) was a German-American theoretical physicist who made major contributions to nuclear physics, astrophysics, quantum electrodynamics, and solid-state physics, and who won the 1967 Nobel ...
, 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 ...
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 ...
. To satisfy the law of
conservation of energy, 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
A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass ...
".
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
In nuclear physics and particle physics, the weak interaction, which is also often called the weak force or weak nuclear force, is one of the four known fundamental interactions, with the others being electromagnetism, the strong 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 physical world or universe. "Nature" can refer to the 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. Although humans are ...
'', 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
Irène Joliot-Curie (; ; 12 September 1897 – 17 March 1956) was a French chemist, physicist and politician, the elder daughter of Pierre and Marie Curie, and the wife of Frédéric Joliot-Curie. Jointly with her husband, Joliot-Curie was awar ...
and
Frédéric Joliot 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 pr ...
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
Sir James Chadwick, (20 October 1891 – 24 July 1974) was an English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932. In 1941, he wrote the final draft of the MAUD Report, which inspi ...
had discovered in 1932. In March 1934, Fermi wanted to see if he could induce radioactivity with Rasetti's
polonium
Polonium is a chemical element with the symbol Po and atomic number 84. Polonium is a chalcogen. A rare and highly radioactive metal with no stable isotopes, polonium is chemically similar to selenium and tellurium, though its metallic character ...
-
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 m ...
neutron source
A neutron source is any device that emits neutrons, irrespective of the mechanism used to produce the neutrons. Neutron sources are used in physics, engineering, medicine, nuclear weapons, petroleum exploration, biology, chemistry, and nuclear p ...
. 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
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams.
Large accelerators are used for fundamental research in particle ...
, which the Via Panisperna boys did not have.
![RasettiFermiSegre](https://upload.wikimedia.org/wikipedia/commons/d/d6/RasettiFermiSegre.JPG)
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.
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 at ...
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".
Pla ...
, 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 ...
, 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 in the form of
calcium fluoride
Calcium fluoride is the inorganic compound of the elements calcium and fluorine with the formula CaF2. It is a white insoluble solid. It occurs as the mineral fluorite (also called fluorspar), which is often deeply coloured owing to impurities.
...
, 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 ...
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 ...
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. 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 discov ...
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.
![Beta-minus Decay](https://upload.wikimedia.org/wikipedia/commons/a/aa/Beta-minus_Decay.svg)
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 ...
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 Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...
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 neutron
The neutron detection temperature, also called the neutron energy, indicates a free neutron's kinetic energy, usually given in electron volts. The term ''temperature'' is used, since hot, thermal and cold neutrons are moderated in a medium with ...
s were more easily
captured than fast ones. He developed a
diffusion equation to describe this, which became known as the
Fermi age equation.
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 nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides. Thus, a nuclear reaction must cause a transformatio ...
s brought about by slow neutrons". After Fermi received the prize in
Stockholm, 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
Otto Hahn (; 8 March 1879 – 28 July 1968) was a German chemist who was a pioneer in the fields of radioactivity and radiochemistry. He is referred to as the father of nuclear chemistry and father of nuclear fission. Hahn and Lise Meitner ...
and
Fritz Strassmann
Friedrich Wilhelm Strassmann (; 22 February 1902 – 22 April 1980) was a German chemist who, with Otto Hahn in December 1938, identified the element barium as a product of the bombardment of uranium with neutrons. Their observation was the ke ...
had detected the element
barium after bombarding uranium with neutrons, which
Lise Meitner and her nephew
Otto Frisch correctly interpreted as the result of
nuclear fission. 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
Niels Henrik David Bohr (; 7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922 ...
, who was to lecture at
Princeton University
Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the ...
.
Isidor Isaac Rabi
Isidor Isaac Rabi (; born Israel Isaac Rabi, July 29, 1898 – January 11, 1988) was an American physicist who won the Nobel Prize in Physics in 1944 for his discovery of nuclear magnetic resonance, which is used in magnetic resonance ima ...
and
Willis Lamb
Willis Eugene Lamb Jr. (; July 12, 1913 – May 15, 2008) was an American physicist who won the Nobel Prize in Physics in 1955 "for his discoveries concerning the fine structure of the hydrogen spectrum." The Nobel Committee that year awarded hal ...
, 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 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. He added a footnote to this effect to his Nobel Prize acceptance speech.
![Stagg Field reactor](https://upload.wikimedia.org/wikipedia/commons/f/fe/Stagg_Field_reactor.jpg)
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 physics and astronomy departments of Columbia University in New York City. The building is located on the south side of 120th Street, just east of Broadway. In 1965, Pupin was ...
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,
Eugene T. Booth,
John R. Dunning,
G. Norris Glasoe, and
Francis G. Slack. The next day, the Fifth Washington Conference on Theoretical Physics began in Washington, D.C. under the joint auspices of
George Washington University
The George Washington University (GW or GWU) is a Private university, private University charter#Federal, federally chartered research university in Washington, D.C. Chartered in 1821 by the United States Congress, GWU is the largest Higher educat ...
and the
Carnegie Institution of Washington
The Carnegie Institution of Washington (the organization's legal name), known also for public purposes as the Carnegie Institution for Science (CIS), is an organization in the United States established to fund and perform scientific research. Th ...
. There, the news on nuclear fission was spread even further, fostering many more experimental demonstrations.
French scientists
Hans von Halban
Hans Heinrich von Halban (24 January 1908 – 28 November 1964) was a French physicist, of Austrian- Jewish descent.
Family
He was descended on his father's side from Polish Jews, who left Kraków for Vienna in the 1850s. His grandfather, Hei ...
,
Lew Kowarski
Lew Kowarski (10 February 1907, Saint Petersburg – 30 July 1979, Geneva) was a naturalized French physicist. He was a lesser-known but important contributor to nuclear science.
Early life
Lew Kowarski was born in Saint Petersburg to Nicholas K ...
, 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
Leo Szilard (; hu, Szilárd Leó, pronounced ; born Leó Spitz; February 11, 1898 – May 30, 1964) was a Hungarian-German-American physicist and inventor. He conceived the nuclear chain reaction in 1933, patented the idea of a nuclear ...
obtained of
uranium oxide
Uranium oxide is an oxide of the element uranium.
The metal uranium forms several oxides:
* Uranium dioxide or uranium(IV) oxide (UO2, the mineral uraninite or pitchblende)
* Diuranium pentoxide or uranium(V) oxide (U2O5)
* Uranium trioxide o ...
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 (rathe ...
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 fr ...
. 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. 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 lar ...
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 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
Eugene Paul "E. P." Wigner ( hu, Wigner Jenő Pál, ; November 17, 1902 – January 1, 1995) was a Hungarian-American theoretical physicist who also contributed to mathematical physics. He received the Nobel Prize in Physics in 1963 "for his co ...
, and
Edward Teller
Edward Teller ( hu, Teller Ede; January 15, 1908 – September 9, 2003) was a Hungarian-American theoretical physicist who is known colloquially as "the father of the hydrogen bomb" (see the Teller–Ulam design), although he did not care for ...
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. 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.
![Enrico Fermi ID badge](https://upload.wikimedia.org/wikipedia/commons/9/9f/Enrico_Fermi_ID_badge.png)
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
The Office of Scientific Research and Development (OSRD) was an agency of the United States federal government created to coordinate scientific research for military purposes during World War II. Arrangements were made for its creation during May 1 ...
, 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 opposing ...
, making its work urgent. Most of the effort sponsored by the committee had been directed at producing
enriched uranium
Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238U ...
, but Committee member
Arthur Compton 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 university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...
. Fermi reluctantly moved, and his team became part of the new
Metallurgical Laboratory 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 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
Squash may refer to:
Sports
* Squash (sport), the high-speed racquet sport also known as squash racquets
* Squash (professional wrestling), an extremely one-sided match in professional wrestling
* Squash tennis, a game similar to squash but pla ...
court under the stands of the University of Chicago's
Stagg Field. Construction of the pile began on 6 November 1942, and
Chicago Pile-1 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
The National Defense Research Committee (NDRC) was an organization created "to coordinate, supervise, and conduct scientific research on the problems underlying the development, production, and use of mechanisms and devices of warfare" in the Un ...
.
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 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 Hanford Site is a decommissioned nuclear production complex operated by the United States federal government on the Columbia River in Benton County in the U.S. state of Washington. The site has been known by many names, including SiteW a ...
, 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 rods 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 poison
In applications such as nuclear reactors, a neutron poison (also called a neutron absorber or a nuclear poison) is a substance with a large neutron absorption cross-section. In such applications, absorbing neutrons is normally an undesirable eff ...
ing 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 ...
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, as she prepared a printed draft on this topic to be published by the
Physical Review. 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.
![Fermiac](https://upload.wikimedia.org/wikipedia/commons/f/f0/Fermiac.jpg)
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
Strontium-90 () is a radioactive isotope of strontium produced by nuclear fission, with a half-life of 28.8 years. It undergoes β− decay into yttrium-90, with a decay energy of 0.546 MeV. Strontium-90 has applications in medicine and ...
. James B. Conant and
Leslie Groves
Lieutenant General Leslie Richard Groves Jr. (17 August 1896 – 13 July 1970) was a United States Army Corps of Engineers officer who oversaw the construction of the Pentagon and directed the Manhattan Project, a top secret research project ...
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
The Los Alamos Laboratory, also known as Project Y, was a secret laboratory established by the Manhattan Project and operated by the University of California during World War II. Its mission was to design and build the first atomic bombs. Ro ...
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 Labo ...
. 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
Research reactors are nuclear fission-based nuclear reactors that serve primarily as a neutron source. They are also called non-power reactors, in contrast to power reactors that are used for electricity production, heat generation, or marit ...
; 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 ...
; and F-4 Fission Studies under Anderson. Fermi observed the
Trinity test
Trinity was the code name of the first detonation of a nuclear weapon. It was conducted by the United States Army at 5:29 a.m. on July 16, 1945, as part of the Manhattan Project. The test was conducted in the Jornada del Muerto desert abo ...
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 fo ...
, Fermi was part of the scientific panel that advised the
Interim Committee 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 from the
public address system
A public address system (or PA system) is an electronic system comprising microphones, amplifiers, loudspeakers, and related equipment. It increases the apparent volume (loudness) of a human voice, musical instrument, or other acoustic sound sou ...
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.
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
The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Natio ...
in 1945.
The Metallurgical Laboratory became the
Argonne National Laboratory 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
Neutron scattering, the irregular dispersal of free neutrons by matter, can refer to either the naturally occurring physical process itself or to the man-made experimental techniques that use the natural process for investigating materials. Th ...
with
Leona Marshall. He also discussed theoretical physics with
Maria Mayer, 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 Rayleigh–Taylor instability, or RT instability (after Lord Rayleigh and G. I. Taylor), is an instability of an interface between two fluids of different densities which occurs when the lighter fluid is pushing the heavier fluid.
Drazin ( ...
, the science of what occurs at the border between two fluids of different densities.
![Laura and Enrico Fermi 1954](https://upload.wikimedia.org/wikipedia/commons/6/6f/Laura_and_Enrico_Fermi_1954.jpg)
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, he calculated that not only would the amount of
tritium
Tritium ( or , ) or hydrogen-3 (symbol T or H) is a rare and radioactive isotope of hydrogen with half-life about 12 years. The nucleus of tritium (t, sometimes called a ''triton'') contains one proton and two neutrons, whereas the nucleus of ...
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
__NOTOC__
The Institute for Nuclear Studies was founded September 1945 as part of the University of Chicago with Samuel King Allison as director. On November 20, 1955, it was renamed The Enrico Fermi Institute for Nuclear Studies. The name was s ...
. 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,
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
Arthur Hinton Rosenfeld (June 22, 1926 – January 27, 2017) was a UC Berkeley physicist and California energy commissioner, dubbed the "Godfather of Energy Efficiency", for developing new standards which helped improve energy efficiency in Cal ...
and
Sam Treiman
Sam Bard Treiman (; May 27, 1925 – November 30, 1999) was an American theoretical physicist who produced research in the fields of cosmic rays, quantum physics, plasma physics, and gravity physics. He made contributions to the understanding of ...
.
[ including the Nobel Lecture, 12 December 1938 ''Artificial Radioactivity Produced by Neutron Bombardment''] Jack Steinberger
Jack Steinberger (born Hans Jakob Steinberger; May 25, 1921December 12, 2020) was a German-born American physicist noted for his work with neutrinos, the subatomic particles considered to be elementary constituents of matter. He was a recipient ...
was a graduate student, and
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
pion
In particle physics, a pion (or a pi meson, denoted with the Greek letter pi: ) is any of three subatomic particles: , , and . Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more gene ...
s and
muons. He made the first predictions of pion-
nucleon
In physics and chemistry, a nucleon is either a proton or a neutron, considered in its role as a component of an atomic nucleus. The number of nucleons in a nucleus defines the atom's mass number (nucleon number).
Until the 1960s, nucleons were ...
resonance, relying on
statistical methods
Statistics (from German: ''Statistik'', "description of a state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, industria ...
, since he reasoned that exact answers were not required when the theory was wrong anyway. In a paper coauthored with
Chen Ning Yang, he speculated that pions might actually be composite particles. The idea was elaborated by
Shoichi Sakata
was a Japanese physicist and Marxist who was internationally known for theoretical work on the subatomic particles.Nussbaum, Louis-Frédéric. (2005). "''Sakata Shōichi''" in ; n.b., Louis-Frédéric is pseudonym of Louis-Frédéric Nussbaum, '' ...
. 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 Ei ...
, 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" 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. He mused about what is now referred to as the "
Fermi paradox
The Fermi paradox is the discrepancy between the lack of conclusive evidence of advanced extraterrestrial life and the apparently high a priori likelihood of its existence, and by extension of obtaining such evidence. As a 2015 article put it, ...
": the contradiction between the presumed probability of the existence of extraterrestrial life and the fact that contact has not been made.
![Enrico fermi tomb2](https://upload.wikimedia.org/wikipedia/commons/a/aa/Enrico_fermi_tomb2.jpg)
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 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 The Matteucci Medal is an Italian award for physicists, named after Carlo Matteucci from Forlì. It was established to award physicists for their fundamental contributions. Under an Italian Royal Decree dated July 10, 1870, the Italian Society ...
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
The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the Am ...
in 1947, and the
Rumford Prize
Founded in 1796, the Rumford Prize, awarded by the American Academy of Arts and Sciences, is one of the oldest scientific prizes in the United States. The prize recognizes contributions by scientists to the fields of heat and light. These terms ...
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,
Florence
Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany Regions of Italy, region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilan ...
, 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, ...
'' 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
Charles Percy Snow, Baron Snow, (15 October 1905 – 1 July 1980) was an English novelist and physical chemist who also served in several important positions in the British Civil Service and briefly in the UK government.''The Columbia Encyclope ...
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
Victor Frederick "Viki" Weisskopf (also spelled Viktor; September 19, 1908 – April 22, 2002) was an Austrian-born American theoretical physicist. He did postdoctoral work with Werner Heisenberg, Erwin Schrödinger, Wolfgang Pauli, and Niels Boh ...
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", and is widely taught.
Fermi was fond of pointing out that when
Alessandro Volta 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
quarks and
leptons.
Things named after Fermi
![Viaenricofermi](https://upload.wikimedia.org/wikipedia/commons/1/14/Via_Enrico_Fermi.jpg)
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 opera ...
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
The Fermi Gamma-ray Space Telescope (FGST, also FGRST), formerly called the Gamma-ray Large Area Space Telescope (GLAST), is a space observatory being used to perform gamma-ray astronomy observations from low Earth orbit. Its main instrument is ...
, 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 ow ...
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
RA-1 Enrico Fermi is a research reactor in Argentina. It wasd the first nuclear reactor to be built in that country and the first research reactor in the south hemisphere.
Construction started April 1957, with first criticality 20 January 1958. It ...
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 ...
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, after him. Recipients of the award have included Otto Hahn, Robert Oppenheimer, Edward Teller and Hans Bethe.
Publications
*
*
*
*
*
* (with
Edoardo Amaldi
Edoardo Amaldi (5 September 1908 – 5 December 1989) was an Italian physicist. He coined the term "neutrino" in conversations with Enrico Fermi distinguishing it from the heavier "neutron". He has been described as "one of the leading nuclear ...
)
*
*
For a full list of his papers, see pages 75–78 in ref.
Patents
*
*
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Notes
References
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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' prizeThe Story of the First PileEnrico Fermi's Case Fileat 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
Richard Lee Rhodes (born July 4, 1937) is an American historian, journalist, and author of both fiction and non-fiction, including the Pulitzer Prize-winning ''The Making of the Atomic Bomb'' (1986), and most recently, ''Energy: A Human Histor ...
29 March 1999
Fermi's stay with Ehrenfest in Leiden
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