Lise Meitner
Lise Meitner in 1946
Born	7 November 1878[1][2] Vienna, Austria-Hungary
Died	27 October 1968(1968-10-27) (aged 89) Cambridge, England
Residence	Austria, Germany, Sweden United Kingdom
Citizenship	Austro-Hungarian (pre 1919), Austria (pre-1949), Sweden (post-1949)
Fields	Physics
Institutions	Kaiser Wilhelm Institute University of Berlin
Alma mater	University of Vienna
Doctoral advisor	Ludwig Boltzmann
Other academic advisors	Max Planck
Doctoral students	Arnold Flammersfeld Kan-Chang Wang Nikolaus Riehl
Other notable students	Max Delbrück Hans Hellmann
Known for	Nuclear fission
Influenced	Otto Hahn
Notable awards	Lieben Prize (1925) Max Planck Medal (1949) Enrico Fermi Award (1966)
Signature
Notes She was the aunt of Otto Robert Frisch. Her father was Philipp Meitner.

Lise Meitner, FRS^[3] (7 November 1878 – 27 October 1968) was an Austrian, later Swedish, physicist who worked on radioactivity and nuclear physics.^[4] Meitner was part of the team that discovered nuclear fission, an achievement for which her colleague Otto Hahn was awarded the Nobel Prize. ^[5] Meitner is often mentioned as one of the most glaring examples of women's scientific achievement overlooked by the Nobel committee.^[6][7][8] A 1997 Physics Today study concluded that Meitner's omission was "a rare instance in which personal negative opinions apparently led to the exclusion of a deserving scientist" from the Nobel.^[9] Element 109, Meitnerium, is named in her honour.^[10][11][12]

Early years[link]

Meitner in 1906

Meitner was born into a Jewish family as the third of eight children in Vienna, 2nd district (Leopoldstadt). Her father, Philipp Meitner,^[13] was one of the first Jewish lawyers in Austria.^[8] She was born on 7 November 1878. She shortened her name from Elise to Lise.^[14][2] The birth register of Vienna's Jewish community lists Meitner as being born on 17 November 1878, but all other documents list it as 7 November, which is what she used.^[1] As an adult, she converted to Christianity, following Lutheranism,^[1][15] and being baptized in 1908.^[16]

Scientific career[link]

Inspired by her teacher, physicist Ludwig Boltzmann, Meitner studied physics and became the second woman to obtain a doctoral degree in physics at the University of Vienna in 1905 ("Wärmeleitung im inhomogenen Körper").^[8] Women were not allowed to attend institutions of higher education in those days, but thanks to support from her parents, she was able to obtain private higher education, which she completed in 1901 with an "externe Matura" examination at the Akademisches Gymnasium. Following the doctoral degree, she rejected an offer to work in a gas lamp factory. Encouraged by her father and backed by his financial support, she went to Berlin. Max Planck allowed her to attend his lectures, an unusual gesture by Planck, who until then had rejected any women wanting to attend his lectures. After one year, Meitner became Planck's assistant. During the first years she worked together with chemist Otto Hahn and discovered with him several new isotopes. In 1909 she presented two papers on beta-radiation.

In 1912 the research group Hahn-Meitner moved to the newly founded Kaiser-Wilhelm-Institut (KWI) in Berlin-Dahlem, south west in Berlin. She worked without salary as a "guest" in Hahn's department of Radiochemistry. It was not until 1913, at 35 years old and following an offer to go to Prague as associate professor, that she got a permanent position at KWI.

In the first part of World War I, she served as a nurse handling X-ray equipment. She returned to Berlin and her research in 1916, but not without inner struggle. She felt in a way ashamed of wanting to continue her research efforts when thinking about the pain and suffering of the victims of war and their medical and emotional needs.^[17]

Lise Meitner and Otto Hahn in their laboratory.

In 1917, she and Hahn discovered the first long-lived isotope of the element protactinium, for which she was awarded the Leibniz Medal by the Berlin Academy of Sciences. That year, Meitner was given her own physics section at the Kaiser Wilhelm Institute for Chemistry.^[8]

In 1922, she discovered the cause, known as the Auger effect, of the emission from surfaces of electrons with 'signature' energies.^[18] The effect is named for Pierre Victor Auger, a French scientist who independently discovered the effect in 1923.^[19]

In 1926, Meitner became the first woman in Germany to assume a post of full professor in physics, at the University of Berlin. There she undertook the research program in nuclear physics which eventually led to her co-discovery of nuclear fission in 1939, after she had left Berlin. She was praised by Albert Einstein as the "German Marie Curie".^[8][20][21]

In 1930, Meitner taught a seminar on nuclear physics and chemistry with Leó Szilárd. With the discovery of the neutron in the early 1930s, speculation arose in the scientific community that it might be possible to create elements heavier than uranium (atomic number 92) in the laboratory. A scientific race began between Ernest Rutherford in Britain, Irène Joliot-Curie in France, Enrico Fermi in Italy, and the Meitner-Hahn team in Berlin. At the time, all concerned believed that this was abstract research for the probable honour of a Nobel prize. None suspected that this research would culminate in nuclear weapons.

When Adolf Hitler came to power in 1933, Meitner was acting director of the Institute for Chemistry. Although she was protected by her Austrian citizenship, all other Jewish scientists, including her nephew Otto Frisch, Fritz Haber, Leó Szilárd and many other eminent figures, were dismissed or forced to resign from their posts. Most of them emigrated from Germany. Her response was to say nothing and bury herself in her work; she later acknowledged, in 1946, that "It was not only stupid but also very wrong that I did not leave at once."^[22]

After the Anschluss, her situation became desperate. In July 1938, Meitner, with help from the Dutch physicists Dirk Coster and Adriaan Fokker, escaped to the Netherlands. She was forced to travel under cover to the Dutch border, where Coster persuaded German immigration officers that she had permission to travel to the Netherlands. She reached safety, though without her possessions. Meitner later said that she left Germany forever with 10 marks in her purse. Before she left, Otto Hahn had given her a diamond ring he had inherited from his mother: this was to be used to bribe the frontier guards if required. It was not required, and Meitner's nephew's wife later wore it.

Meitner was lucky to escape, as Kurt Hess, a chemist who was an avid Nazi, had informed the authorities that she was about to flee. An appointment at the University of Groningen did not come through, and she went instead to Stockholm, where she took up a post at Manne Siegbahn's laboratory, despite the difficulty caused by Siegbahn's prejudice against women in science. Here she established a working relationship with Niels Bohr, who travelled regularly between Copenhagen and Stockholm. She continued to correspond with Hahn and other German scientists.^[23]

Nuclear fission[link]

Hahn and Meitner met privately in Copenhagen in November to plan a new round of experiments, and they subsequently exchanged a series of letters. Hahn and Fritz Strassmann then performed the difficult experiments which isolated the evidence for nuclear fission at his laboratory in Berlin. The surviving correspondence shows that Hahn recognized that fission was the only explanation for the barium, but, baffled by this remarkable conclusion, he wrote to Meitner. The possibility that uranium nuclei might break up under neutron bombardment had been suggested years before, notably by Ida Noddack in 1934. However, by employing the existing "liquid-drop" model of the nucleus,^[24] Meitner and Frisch were the first to articulate a theory of how the nucleus of an atom could be split into smaller parts: uranium nuclei had split to form barium and krypton, accompanied by the ejection of several neutrons and a large amount of energy (the latter two products accounting for the loss in mass). She and Frisch had discovered the reason that no stable elements beyond uranium (in atomic number) existed naturally; the electrical repulsion of so many protons overcame the strong nuclear force.^[24] Meitner also first realized that Einstein's famous equation, E = mc², explained the source of the tremendous releases of energy in nuclear fission, by the conversion of rest mass into kinetic energy, popularly described as the conversion of mass into energy.

Nuclear fission experimental setup, reconstructed at the Deutsches Museum, Munich.

A letter from Bohr, commenting on the fact that the amount of energy released when he bombarded uranium atoms was far larger than had been predicted by calculations based on a non-fissile core, had sparked the above inspiration in December 1938. Hahn claimed that his chemistry had been solely responsible for the discovery, although he had been unable to explain the results.

It was politically impossible for the exiled Meitner to publish jointly with Hahn in 1939. Hahn and Strassman had sent the manuscript of their paper to Naturwissenschaften in December 1938, reporting they had detected the element barium after bombarding uranium with neutrons;^[25] simultaneously, they had communicated their results to Meitner in a letter. Meitner, and her nephew Otto Frisch, correctly interpreted their results as being nuclear fission and published their paper in Nature.^[26] Frisch confirmed this experimentally on 13 January 1939.^[27]

Meitner recognized the possibility for a chain reaction of enormous explosive potential. This report had an electrifying effect on the scientific community. Because this could be used as a weapon, and since the knowledge was in German hands, Leó Szilárd, Edward Teller, and Eugene Wigner jumped into action, persuading Albert Einstein, a celebrity, to write President Franklin D. Roosevelt a letter of caution; this led eventually to the establishment several years later of the Manhattan Project. Meitner refused an offer to work on the project at Los Alamos, declaring "I will have nothing to do with a bomb!"^[28] Meitner said that Hiroshima had come as a surprise to her, and that she was "sorry that the bomb had to be invented."^[29]

In Sweden, Meitner was first active at Siegbahn's Nobel Institute for Physics, and at the Swedish Defence Research Establishment (FOA) and the Royal Institute of Technology in Stockholm, where she had a laboratory and participated in research on R1, Sweden's first nuclear reactor. In 1947, a personal position was created for Meitner at the University College of Stockholm with the salary of a professor and funding from the Council for Atomic Research.^[30]

Awards and honours[link]

Meitner with actress Katherine Cornell and physicist Arthur Compton on 6 June 1946, when Meitner and Cornell were receiving awards from the National Conference of Christians and Jews.

On 15 November 1945 the Royal Swedish Academy of Sciences announced that Hahn had been awarded the 1944 Nobel Prize in Chemistry for the discovery of nuclear fission.^[31] Some historians who have documented the history of the discovery of nuclear fission believe Meitner should have been awarded the Nobel Prize with Hahn.^[32][33][34]

In 1966 Hahn, Fritz Strassmann and Meitner together were awarded the Enrico Fermi Award. On a visit to the USA in 1946 she received the honour of the "Woman of the Year" by the National Press Club dinner with President Harry Truman and others at the National Women's Press Club (USA) in January 1946, as well as many honorary doctorates and lectured at Princeton, Harvard and other US universities. Lise Meitner refused to move back to Germany, and enjoyed retirement and research in Stockholm until her late 80s. She received the Max Planck Medal of the German Physics Society in 1949. Meitner was nominated to receive the prize three times. An even rarer honour was given to her in 1997 when element 109 was named meitnerium in her honour.^[8][35][36] Named after Meitner were the Hahn-Meitner Institut in Berlin, craters on the Moon and on Venus, and a main-belt asteroid.

Meitner was elected a foreign member of the Royal Swedish Academy of Sciences in 1945, and had her status changed to that of a Swedish member in 1951.

Later years[link]

After the war, Meitner, while acknowledging her own moral failing in staying in Germany from 1933 to 1938, was bitterly critical of Hahn and other German scientists who had collaborated with the Nazis and done nothing to protest against the crimes of Hitler's regime. Referring to the leading German scientist Werner Heisenberg, she said: "Heisenberg and many millions with him should be forced to see these camps and the martyred people." She wrote to Hahn:

You all worked for Nazi Germany. And you tried to offer only a passive resistance. Certainly, to buy off your conscience you helped here and there a persecuted person, but millions of innocent human beings were allowed to be murdered without any kind of protest being uttered ... [it is said that] first you betrayed your friends, then your children in that you let them stake their lives on a criminal war – and finally that you betrayed Germany itself, because when the war was already quite hopeless, you did not once arm yourselves against the senseless destruction of Germany.

—^[37]

Hahn however wrote in his memoirs that he and Meitner had been lifelong friends.^[38]

Meitner became a Swedish citizen in 1949. She finally decided to retire in 1960 and then moved to the UK where most of her relatives were, although she continued working part time and giving lectures. A strenuous trip to the United States in 1964 led to Meitner having a heart attack, which she spent several months recovering from. Her physical and mental condition weakened by atherosclerosis, she was unable to travel to the US to receive the Enrico Fermi prize and relatives had to present it to her. After breaking her hip in a fall and suffering several small strokes in 1967, Meitner made a partial recovery, but eventually was weakened to the point where she moved into a Cambridge nursing home. She died on 27 October at the age of 89. Meitner was not informed of the deaths of Otto Hahn and his wife Edith, as her family believed it would be too much for someone as frail as her to handle. ^[4] As was her wish, she was buried in the village of Bramley in Hampshire, at St. James parish church, close to her younger brother Walter, who had died in 1964. Her nephew Otto Frisch composed the inscription on her headstone. It reads "Lise Meitner: a physicist who never lost her humanity."

See also[link]

• List of Austrian scientists
• Hans-Hermann Hupfeld
• List of German inventors and discoverers

References[link]

Further reading[link]

External links[link]

Wikimedia Commons has media related to: Lise Meitner

• "Lise Meitner" in CWP at UCLA
• Annotated bibliography for Lise Meitner from the Alsos Digital Library for Nuclear Issues
• Wired.com: "February 11, 1939: Lise Meitner, 'Our Madame Curie'"
• "Lise Meitner," B. Weintraub, Chemistry in Israel, no. 21, May 2006, p. 35.

The topic of this article may not meet Wikipedia's notability guideline for biographies. Please help to establish notability by adding reliable, secondary sources about the topic. If notability cannot be established, the article is likely to be merged, redirected, or deleted. (July 2011)

Ernst Peter Fischer

Ernst Peter Fischer (born 18 January 1947 in Wuppertal) is a German historian of science, and a science publicist.

Life and Work[link]

Ernst Peter Fischer studied mathematics, physics and biology and graduated from the California Institute of Technology in 1977. In 1987 he qualified as a university lecturer in the history of science, and taught as a professor at the University of Konstanz. Between 1989 and 1999 he was publisher of the Mannheimer Forum This position was previously held by Hoimar von Ditfurth.

During his free days, Fischer also engaged in scientific journalism, as well as spending time as a mentor. He worked as a publisher for the Stiftung Forum für Verantwortung.

As a science publisher, Fisher wrote articles for several newspapers. Among them were GEO, Bild der Wissenschaft, Die Weltwoche and the Frankfurter Allgemeine Zeitung.

Awards[link]

Fischer's published work has received multiple awards.^[1]

• 2002: Lorenz-Oken-Medaille
• 2003: Treviranus-Medaille
• 2003: Eduard-Rhein-Kulturpreis
• 2004: Medaille für Naturwissenschaftliche Publizistik der Deutschen Physikalischen Gesellschaft
• 2004: Sartorius-Preis der Akademie der Wissenschaften zu Göttingen
• 2011: Honorary member of the Naturforschende Gesellschaft zu Emden

Published works[link]

• Warum Spinat nur Popeye stark macht. Mythen und Legenden in der modernen Wissenschaft. Pantheon Verlag, München 2011, ISBN 978-3-570-55123-3.
• Information - eine kurze Geschichte in 5 Kapiteln. Verlagshaus Jacoby & Stuart 2010, ISBN 978-3-941787-15-5.
• Die Hintertreppe zum Quantensprung. Die Erforschung der kleinsten Teilchen der Natur von Max Planck bis Anton Zeilinger. Herbig Verlag, München 2010, ISBN 978-3-7766-2643-8.
• Laser - Eine deutsche Erfolgsgeschichte von Einstein bis heute. Siedler-Verlag, München 2010, ISBN 978-3-88680-946-2.
• Die Charité: Ein Krankenhaus in Berlin - 1710 bis heute. Siedler-Verlag, München 2009, ISBN 978-3-88680-880-9.
• Die kosmische Hintertreppe: Die Erforschung des Himmels von Aristoteles bis Stephen Hawking. Nymphenburger Verlag, München 2009, ISBN 978-3-485-01186-0.
• Der kleine Darwin. Alles, was man über Evolution wissen sollte. Pantheon Verlag, München 2009, ISBN 978-3-570-55087-8.
• Das große Buch der Evolution. Fackelträger Verlag, Köln 2008, ISBN 978-3-7716-4373-7.
• Einfach klug: 60 Ratschläge für ein gelingendes Leben. Nymphenburger Verlag, München 2009, ISBN 978-3-485-01118-1.
• Irren ist bequem: Wissenschaft quer gedacht. Kosmos Verlag, Stuttgart 2007, ISBN 978-3-440-11098-0.
• Der Physiker: Max Planck und das Zerfallen der Welt. Siedler Verlag, München 2007, ISBN 978-3-570-55116-5.
• Max Planck - ein Porträt. Eine Vorlesung (auf DVD) von Ernst Peter Fischer über die Physik, das tragische Leben, sowie Religiosität und Philosophie von Max Planck. Rezension - Komplett Media GmbH, 2007, DVD: ISBN 978-3-8312-9522-7 CD: ISBN 978-3-8312-6225-0.
• Die Nachtseite der Wissenschaft. Vorlesung aus der Reihe "uni-auditorium", Audio CD, Komplett Media, Juni 2007, ISBN 978-3-8312-6194-9.
• Schrödingers Katze auf dem Mandelbrotbaum: Durch die Hintertür zur Wissenschaft. Pantheon Verlag, München 2006, ISBN 978-3-442-15510-1.
• Brücken zum Kosmos: Wolfgang Pauli zwischen Kernphysik und Weltharmonie. Libelle Verlag, Lengwil (CH) 2005, ISBN 978-3-909081-44-8.
• Einstein trifft Picasso und geht mit ihm ins Kino oder: Die Erfindung der Moderne. Piper Verlag, München 2005, ISBN 978-3-492-04682-4.
• Einstein für die Westentasche. Piper Verlag, München 2005, ISBN 978-3-492-04685-5.
• Was Professor Kuckuck noch nicht wusste. (mit Henning Genz) Rowohlt Verlag, Reinbek 2004, ISBN 978-3-499-61580-1.
• Die Bildung des Menschen: Was die Naturwissenschaften über uns wissen. Ullstein Verlag, Berlin 2004, ISBN 978-3-550-07606-0.
• Stille Kräfte, große Fülle: Die Geschichte der Südchemie AG. Piper Verlag, München 2004, ISBN 978-3-492-04582-7.
• Einstein, Hawking, Singh & Co.: Bücher, die man kennen muß. Piper Verlag, München 2004, ISBN 978-3-492-04551-3.
• Geschichte des Gens. James D. Watson und die neue Wissenschaft vom Leben. Fischer Verlag, Frankfurt am Main 2003, ISBN 978-3-596-15363-3.
• Am Anfang war die Doppelhelix: James D. Watson und die neue Wissenschaft vom Leben. Ullstein Verlag, Berlin 2003, ISBN 978-3-550-07566-7.
• Das Genom. Fischer Verlag, Frankfurt am Main 2002, ISBN 978-3-596-15362-6.
• Das genetische Abenteuer. My favourite book, Düsseldorf 2001, ISBN 978-3-936143-19-5.
• Images & Imagination. Editiones Roche, Basel 2001, ISBN 978-3-907770-86-3.
• Werner Heisenberg: Das selbstvergessene Genie. Piper Verlag, München 2001, ISBN 978-3-492-03855-3.
• Die andere Bildung. Was man von den Naturwissenschaften wissen sollte. Ullstein Verlag, Berlin 2001, ISBN 978-3-550-07151-5.
• An den Grenzen des Denkens: Wolfgang Pauli - Ein Nobelpreisträger über die Nachtseiten der Wissenschaft. Herder Verlag, Freiburg 2000, ISBN 978-3-451-04842-5.
• Leonardo, Heisenberg & Co.: Eine kleine Geschichte der Wissenschaft in Porträts. Piper Verlag, München 2000, ISBN 978-3-492-03942-0.
• Aristoteles, Einstein & Co.: Eine kleine Geschichte der Wissenschaft in Porträts. Piper Verlag, München 1995, ISBN 978-3-492-04817-0.
• Ernst Peter Fischer and Carol Lipson: Thinking About Science. Max Delbrück and the Origins of Molecular Biology. Rezension W.W. Norton & Company, New York 1988, ISBN 978-0-393-02508-8

References[link]

1. ^ Biografie bei Econ Referentenagentur

External links[link]

Wikiquote has a collection of quotations related to: Ernst Peter Fischer

• Literature by and about Ernst Peter Fischer in the German National Library catalogue
• Persönliche Website von Ernst Peter Fischer
• Fischers Science-Blog
• E. P. Fischer: Der Affe als Mensch, der Mensch als Affe. Darwin und seine Evolutionstheorie. SWR2 Aula Sendung Sendung - Manuskript - Vortrag hören

Otto Hahn
Hahn in 1944
Born	(1879-03-08)8 March 1879 Frankfurt am Main, Hesse-Nassau, Prussia, German Empire
Died	28 July 1968(1968-07-28) (aged 89) Göttingen, West Germany
Nationality	German
Fields	Radiochemistry, nuclear chemistry
Alma mater	University of Marburg
Doctoral advisor	Theodor Zincke
Other academic advisors	Sir William Ramsay, University College London, Ernest Rutherford, McGill University Montreal, Emil Fischer, Berlin
Doctoral students	Roland Lindner, Walter Seelmann-Eggebert, Fritz Strassmann, Karl Erik Zimen, Hans Joachim Born, Hans Götte, Siegfried Flügge
Known for	Discovery of radioactive elements (1905-1921) Radioactive Recoil (1909) Fajans-Paneth-Hahn Law Protactinium (1917) Nuclear isomerism (1921) Applied Radiochemistry (1936) Nuclear fission (1938)
Notable awards	Emil Fischer Medal (1919) Cannizzaro Prize (1939) Copernicus Prize (1941) Nobel Prize in Chemistry (1944) Max Planck Medal (1949) Pour le Mérite (1952) Faraday Medal (1956) Légion d'Honneur (1959) Enrico Fermi Award (1966)
Signature

Otto Hahn FRS^[1] (8 March 1879 – 28 July 1968) was a German chemist and Nobel laureate, a pioneer in the fields of radioactivity and radiochemistry.^[2] He is regarded as "the father of nuclear chemistry". Hahn was a courageous opposer of Jewish persecution by the Nazis and after World War II he became a passionate campaigner against the use of nuclear energy as a weapon. He served as the last President of the Kaiser Wilhelm Society (KWG) in 1946 and as the founding President of the Max Planck Society (MPG) from 1948 to 1960. Considered by many to be a model for scholarly excellence and personal integrity, he became one of the most influential citizens of the Federal Republic of Germany.

Biography[link]

Early life[link]

Hahn was the youngest son of Heinrich Hahn (1845–1922), a prosperous glazier and entrepreneur ("Glasbau Hahn"), and Charlotte Hahn, née Giese (1845–1905). Together with his brothers Karl, Heiner and Julius, Otto was raised in a sheltered environment. At the age of 15, he began to take a special interest in chemistry and carried out simple experiments in the laundry room of the family home. His father wanted Otto to study architecture, as he had built or acquired several residential and business properties. But Otto persuaded him that his ambition was to become an industrial chemist.

In 1897, after taking his Abitur at the Klinger Oberrealschule in Frankfurt, Hahn began to study chemistry and mineralogy at the University of Marburg. His subsidiary subjects were physics and philosophy. Hahn joined the Students' Association of Natural Sciences and Medicine, a student fraternity and a forerunner of today's Nibelungia Fraternity. He spent his third and fourth semester studying under Adolf von Baeyer at the University of Munich. In 1901, Hahn received his doctorate in Marburg for a dissertation entitled On Bromine Derivates of Isoeugenol, a topic in classical organic chemistry. After completing his one year military service, the young chemist returned to the University of Marburg, where for two years he worked as assistant to his doctoral supervisor, Geheimrat Professor Theodor Zincke.

Career[link]

Early research[link]

Hahn's intention had been to work in industry. With this in mind, and also to improve his knowledge of English, he took up a post at University College London in 1904, working under Sir William Ramsay, known for having discovered the inert gases. Here Hahn worked on radiochemistry, at that time a very new field. In 1905, in the course of his work with salts of radium, Hahn discovered a substance he called radiothorium (thorium 228), which at that time was believed to be a new radioactive element. (In fact, it was a still undiscovered isotope of the known element thorium. The terms "isotopy" and "isotope" were only coined in 1913, by the British chemist Frederick Soddy). In the months between late 1905 and early 1906, Hahn visited Montreal, Canada, where he investigated alpha-rays of radiothorium and "radioactinium" (later identified as thorium-227)^[3] with Ernest Rutherford who was teaching at McGill University at the time.

In 1906, Hahn returned to Germany, where he collaborated with Emil Fischer at the University of Berlin. Fischer placed at his disposal a former woodworking shop ("Holzwerkstatt") in the Chemical Institute to use as his own laboratory. There, in the space of a few months, using extremely primitive apparatus, Hahn discovered mesothorium I, mesothorium II and - independently from Bertram Boltwood - the mother substance of radium, ionium. In subsequent years, mesothorium I (radium-228) assumed great importance because, like radium-226 (discovered by Pierre and Marie Curie), it was ideally suited for use in medical radiation treatment, while costing only half as much to manufacture. (In 1914, for the discovery of mesothorium I, Otto Hahn was first nominated for the Nobel Prize in Chemistry by Adolf von Baeyer). In June 1907, by means of the traditional habilitation thesis, Hahn qualified to teach at the University of Berlin. On 28 September 1907 he made the acquaintance of the young Austrian physicist Lise Meitner, who had transferred from Vienna to Berlin. So began the thirty-year collaboration and lifelong close friendship between the two scientists.

After the physicist Harriet Brooks had observed a radioactive recoil in 1904, but interpreted it wrongly, Otto Hahn succeeded, in the winter of 1908/09, in demonstrating the radioactive recoil incident to alpha particle emission and interpreting it correctly. "...a profoundly significant discovery in physics with far-reaching consequences", as the physicist Walther Gerlach put it.

In 1910 Hahn was appointed professor, and in 1912 he became head of the Radioactivity Department of the newly founded Kaiser Wilhelm Institute for Chemistry in Berlin-Dahlem (since 1956 "Otto Hahn Building of the Free University", Berlin, Thielallee 63). Succeeding Alfred Stock, Hahn was director of the institute from 1928 to 1946. As early as 1924, Hahn was elected to full membership of the Prussian Academy of Sciences in Berlin (proposed by Einstein, Planck, Fritz Haber, Schlenk and von Laue).

In June 1911, while attending a conference in Stettin (today Szczecin, Poland) Otto Hahn met Edith Junghans (1887–1968), an art student. On 22 March 1913 the couple married in Edith's native city of Stettin, where her father, Paul Ferdinand Junghans, was a high-ranking law officer and President of the City Parliament until his 1915 death. Their only child, Hanno, born in 1922, became a distinguished art historian and architectural researcher (at the Hertziana in Rome). In 1960, while on a study trip in France, Dr Hanno Hahn was involved in a fatal car accident, together with his wife and assistant Ilse Hahn, née Pletz. They left a fourteen-year-old son, Dietrich. In 1990, the "Hanno and Ilse Hahn Prize for Outstanding Contributions to Italian Art History" was established to support talented young art historians and in memory of Hanno and Ilse Hahn. It is awarded biennally by the Bibliotheca Hertziana, Max Planck Institute for Art History, in Rome.

Hahn and Meitner, 1913

During the First World War, Hahn was conscripted into the army, where he was assigned, together with James Franck and Gustav Hertz, to the special unit for chemical warfare under the direction of Fritz Haber. The unit developed, tested and produced poison gas for military purposes, and was sent to both the western and eastern front lines. In December 1916, Hahn was transferred to the "Headquarters of His Majesty" in Berlin, and was able to resume his radiochemical research in his institute. In 1917/18 Hahn and Lise Meitner isolated a long-lived activity, which they named "proto-actinium". Already in 1913, Kazimierz Fajans and Göhring had isolated a short-lived activity from uranium X2 (later known as ^234mPa) and called the substance "brevium". The two activities were different isotopes of the same undiscovered element no. 91. Finally in 1949, the International Union of Pure and Applied Chemistry (IUPAC) named this new element protactinium and confirmed Hahn and Meitner as discoverers.

In February 1921, Otto Hahn published the first report on his discovery of uranium Z (later known as ²³⁴Pa),^[4] the first example of nuclear isomerism. "...a discovery that was not understood at the time but later became highly significant for nuclear physics", as Walther Gerlach remarked. And, indeed, it was not until 1936 that the young physicist Carl Friedrich von Weizsäcker succeeded in providing a theoretical explanation of the phenomenon of nuclear isomerism. For this discovery, whose full significance was recognized by very few, Hahn was again proposed, in 1923, for the Nobel Prize in Chemistry, this time by Max Planck, among others.

In the early 1920s, Otto Hahn created a new field of work. Using the "emanation method", which he had recently developed, and the "emanation ability", he founded what became known as "Applied Radiochemistry" for the researching of general chemical and physical-chemical questions. In 1933 he published a book in English (and later in Russian) entitled "Applied Radiochemistry". It contains the lectures given by Hahn when he was a visiting professor at Cornell University in Ithaca, New York in 1933. In 1966, Glenn T. Seaborg, President of the United States Atomic Energy Commission, wrote about this book as follows:

"As a young graduate student at the University of California at Berkeley in the mid-1930s and in connection with our work with plutonium a few years later, I used his book "Applied Radiochemistry" as my bible. This book was based on a series of lectures which Professor Hahn had given at Cornell in 1933; it set forth the "laws" for the co-precipitation of minute quantities of radioactive materials when insoluble substances were precipitated from aqueous solutions. I recall reading and rereading every word in these laws of co-precipitation many times, attempting to derive every possible bit of guidance for our work, and perhaps in my zealousness reading into them more than the master himself had intended. I doubt that I have read sections in any other book more carefully or more frequently than those in Hahn's Applied Radiochemistry. In fact, I read the entire volume repeatedly and I recall that my chief disappointment with it was its length. It was too short."

Discovery of nuclear fission[link]

Jointly with Lise Meitner and his pupil and assistant Fritz Straßmann (1902–1980), Otto Hahn furthered the research begun by Enrico Fermi and his team in 1934 when they bombarded uranium with neutrons. Until 1938, it was believed that the elements with atomic numbers greater than 92 (known as transuranium elements) arise when uranium atoms are bombarded with neutrons. The German chemist Ida Noddack proposed an exception. She anticipated the paradigm shift of 1938/39 in her article published in the journal Angewandte Chemie, Nr. 47, 1934, in which she speculated:

"It is conceivable that when heavy nuclei are bombarded with neutrons these nuclei could break down into several fairly large fragments, which are certainly isotopes of known elements, but not neighbours of the irradiated elements."

But no physicist or chemist really took Noddack's speculation seriously or tested it, not even Ida Noddack herself. The idea that heavy atomic nuclei could break down into lighter elements was regarded as totally inadmissible.

Between 1934 and 1938, Hahn, Meitner, and Strassmann found a great number of radioactive transmutation products, all of which they regarded as transuranic.^[5] At that time the existence of actinides was not yet established, and uranium was wrongly believed to be a group 6 element similar to tungsten. It followed that first transuranic elements would be similar to group 7 to 10 elements, i.e. rhenium and platinoids. Hahn group was indeed able to establish the presence of multiple isotopes of at least four such elements and (mistakenly) identify them as elements with atomic numbers 93 through 96. They were the first scientists to measure the half-life of ²³⁹U and to establish chemically that it was an isotope of uranium, but they were unable to continue this work to its logical conclusion and to identify the decay product of ²³⁹U - namely, neptunium (the real element 93); this task was only completed by Edwin McMillan and Philip H. Abelson in 1940.

Nuclear fission experimental setup, reconstructed at the Deutsches Museum, Munich.

Otto Hahn's notebook

On 13 July 1938, with the help and support of Hahn, Lise Meitner, who was at great risk as she was of Jewish ancestry and had lost her Austrian citizenship after the Anschluss, emigrated to Stockholm, Sweden by crossing the German-Dutch border illegally.^[6] Hahn continued to work with Strassmann. In late 1938 they found evidence of isotopes of an alkaline earth metal in their sample. The metal was detected by the use of an organic barium salt constructed by Wilhelm Traube, a Jewish chemist who was later arrested and murdered despite Hahn's efforts to save him.^{[citation needed]} Finding a group 2 alkaline earth metal was problematic, because it did not logically fit with the other elements found thus far. Hahn initially suspected it to be radium, produced by splitting off two alpha-particles from the uranium nucleus. At the time, the scientific consensus was that even splitting off two alpha particles via this process was unlikely. The idea of turning uranium into barium (by removing around 100 nucleons) was seen as preposterous. On 10 November during a visit to Copenhagen, Hahn discussed these results with Niels Bohr and Lise Meitner.^[6] Further refinements of the technique, leading to the decisive experiment on 16–17 December 1938 (the celebrated "radium-barium-mesothorium-fractionation"), produced puzzling results: the three isotopes consistently behaved not as radium, but as barium. Hahn described the results in a letter to Meitner on 19 December: "...we are more and more coming to the awful conclusion that our Ra isotopes behave not like Ra, but like Ba. ... Perhaps you can suggest some fantastic explanation. We ourselves realize that it can't really burst into Ba."^[7] In her reply, Meitner concurred that bursting of the uranium nucleus was very difficult to accept, but considered it possible.

On 22 December 1938, Hahn sent a manuscript to Naturwissenschaften reporting their radiochemical results.^[8] On 27 December, Hahn telephoned the editor of Naturwissenschaften and requested to add a paragraph to the article, speculating that some platinum group elements previously observed in irradiated uranium, which were originally interpreted as transuranium elements, could in fact be technetium (then called "Masurium") and lower platinum group metals (atomic numbers 43 through 46). By January 1939 he was sufficiently convinced that formation of light elements was occurring in his setup that he published a new revision of the article, essentially retracting former claims of observing transuranic elements and neighbors of uranium, and concluding instead that he was seeing light platinoids, barium, lanthanum, and cerium.

As a chemist, Hahn was reluctant to propose a revolutionary discovery in physics.^[5] However, Lise Meitner and her nephew, the young physicist Otto Robert Frisch, in Sweden, came to the same conclusion and were able to work out the basic mathematics of nuclear fission - the term that was coined by Frisch, and which subsequently became internationally known. Over the next few months, Meitner and Frisch published two articles discussing and experimentally confirming this hypothesis.^[9][10]

In a later appreciation, Meitner wrote:

"The discovery of nuclear fission by Otto Hahn and Fritz Strassmann opened up a new era in human history. It seems to me that what makes the science behind this discovery so remarkable is that it was achieved by purely chemical means."^{[citation needed]}

In an interview on West German television (ARD, 8 March 1959), Meitner said:

"Hahn and Strassmann were able to do this by exceptionally good chemistry, fantastically good chemistry, which was way ahead of what anyone else was capable of at that time. The Americans learned to do it later. But at that time, Hahn and Strassmann were really the only ones who could do it. And that was because they were such good chemists. Somehow they really succeeded in using chemistry to demonstrate and prove a physical process."^{[citation needed]}

Fritz Strassmann responded with this clarification:

"Professor Meitner stated that the success could be attributed to chemistry. I have to make a slight correction. Chemistry merely isolated the individual substances, it did not precisely identify them. It took Professor Hahn's method to do this. This is where his achievement lies."^{[citation needed]}

(Citation sources: Lise Meitner - Recollections of Otto Hahn. Stuttgart 2005).

In their second publication on nuclear fission (Die Naturwissenschaften, 10 February 1939) Otto Hahn and Fritz Strassmann predicted the existence and liberation of additional neutrons during the fission process, which was proved to be a chain reaction by Frédéric Joliot and his team in March 1939.

During the war, Otto Hahn - together with his assistants Hans-Joachim Born, Siegfried Flügge, Hans Götte, Walter Seelmann-Eggebert and Fritz Strassmann - worked on uranium fission reactions. By 1945 he had drawn up a list of 25 elements and about 100 isotopes whose existence he had demonstrated.

Thanks to his determined intervention, Hahn, who had always been an opponent of the Nazi dictatorship, was able to support numerous members of his institute whose lives were in danger or were suffering persecution, and prevent them from being sent to the front line or deported. In this, he was assisted by his courageous wife Edith, who had for years collected food for Jews hiding in Berlin. As early as 1934, Hahn resigned from the University of Berlin to protest the dismissal of Jewish colleagues and those with Jewish ancestry, notably Lise Meitner, Fritz Haber, and James Franck.

At the end of World War II in 1945 Hahn was suspected of working on the German nuclear energy project to develop an atomic reactor or an atomic bomb. But his only connection was the discovery of fission; he did not work on the program. In early 1945 Hahn gave himself up to T-Force members of the 5th King's Regiment, Hahn approaching Private H. Hilton, a member of the intelligence platoon, who had just stopped his vehicle in a town centre, and requested to be taken to the British authorities. Failing to be understood, Hahn then stated; "Perhaps I should introduce myself; I am Professor Hahn, chief scientist for atomic research in Germany". Hilton, not understanding the meaning of this, nevertheless complied with Hahn's request.^[11]

Hahn and nine German physicists (including Max von Laue, Werner Heisenberg and Carl Friedrich von Weizsäcker) were interned at Farm Hall, Godmanchester, near Cambridge, England from 3 July 1945 to 3 January 1946. While they were there, the German scientists learned of the dropping of the American atom bombs on Hiroshima and Nagasaki on 6 August and 9 August 1945. Hahn was on the brink of despair, as he felt that because he had discovered nuclear fission he shared responsibility for the death and suffering of hundreds of thousands of Japanese people.^{[citation needed]} Early in January 1946, the group was allowed to return to Germany.

Nobel Prize[link]

On 15 November 1945 the Royal Swedish Academy of Sciences announced that Hahn had been awarded the 1944 Nobel Prize in Chemistry "for his discovery of the fission of heavy atomic nuclei."^[12][13][14] Some historians have documented the history of the discovery of nuclear fission and believe Meitner should have been awarded the Nobel Prize with Hahn.^[15][16][17] Hahn was still being detained at Farm Hall when the announcement was made; thus, his whereabouts were a secret and it was impossible for the Nobel committee to send him a congratulatory telegram. Instead, he learned about his award through the Daily Telegraph newspaper^[18] His fellow interned German scientists celebrated his award on 18 November by giving speeches, making jokes, and composing songs.^[19] On 4 December, Hahn was persuaded by two of his captors to write a letter to the Nobel committee accepting the prize but also stating that he would not be able to attend the award ceremony.^[20] He could not participate in the Nobel festivities on 10 December since his captors would not allow him to leave Farm Hall.

"There is no doubt at all that Hahn fully deserves the Nobel Prize in Chemistry" wrote Lise Meitner to her friend Eva von Bahr-Bergius in November 1945.^[21] Meitner's former assistant Carl Friedrich von Weizsäcker later added: "He certainly did deserve this Nobel Prize. He would have deserved it even if he had not made this discovery. But everyone recognized that the splitting of the atomic nucleus merited a Nobel Prize."^[21]

Hahn attended the Nobel festivities the year after he was awarded the prize. On 10 December 1946, King Gustav V of Sweden finally presented him with his Nobel Prize medal and diploma.^[14]

Max Planck Society[link]

From 1948 to 1960 Otto Hahn was the founding President of the newly formed Max Planck Society for the Advancement of Science, which through his tireless activity and his worldwide respected personality succeeded in regaining the renown once enjoyed by the Kaiser Wilhelm Society. Immediately after the Second World War, Hahn reacted to the dropping of the atomic bombs on Hiroshima and Nagasaki by coming out strongly against the use of nuclear energy for military purposes. He saw the application of his scientific discoveries to such ends as a misuse, or even a crime. Consequently, among other things, he initiated the Mainau Declaration of 1955, in which a large number of Nobel Prize-winners called attention to the dangers of atomic weapons and warned the nations of the world urgently against the use of "force as a final resort". He was also instrumental and one of the authors of the Göttingen Manifesto of 1957, in which, together with 17 leading German atomic scientists, he protested against a proposed nuclear arming of the new West German armed forces (Bundeswehr). In January 1958, Otto Hahn signed the Pauling Appeal to the United Nations for the "immediate conclusion of an international agreement to stop the testing of nuclear weapons", and in October he signed the international Agreement to call a meeting to draw up a world constitution. Right up to his death, he never tired of warning urgently of the dangers of the nuclear arms race between the great powers and of the radioactive contamination of the planet. From 1957, Hahn was repeatedly nominated for the Nobel Peace Prize by a number of organizations, including the largest French trade union, the Confederation Generale du Travail. Linus Pauling, the 1962 Nobel Peace laureate, once described Otto Hahn as "an inspiration to me."

Honours and awards[link]

Hahn received many governmental honours and academic awards from all over the world. He was elected member or honorary member in 45 Academies and scientific societies (among them the Royal Society in London ^[1] and the Academies in Allahabad (India), Bangalore (India), Boston (USA), Bucharest, Copenhagen, Helsinki, Lisbon, Madrid, Rome, Stockholm, Vienna) and received 37 of the highest national and international orders and medals (among them the Golden Paracelsus Medal from the Swiss Chemical Society and the Faraday Medal from the British Chemical Society). In 1959 President Charles de Gaulle of France made him an Officer of the Légion d'Honneur, he was made a knight of the Peace Class of the Order Pour le Mérite, received the Distinguished Service Order and the Grand Cross of the Federal Republic of Germany. In 1961 Pope John XXIII awarded him the Gold Medal of the Papal Academy. (In 1957 Hahn was elected an honorary citizen of the city of Magdeburg, German Democratic Republic, and in 1958 an honorary member of the Soviet Academy of Science in Moscow. He declined both honours).

In 1966, President Lyndon B. Johnson of the USA, and the USA Atomic Energy Commission awarded Hahn (together with Lise Meitner and Fritz Strassmann) the Enrico Fermi Prize. This was the only time the Fermi Prize has been awarded to non-Americans.

Hahn was made an honorary citizen of the cities of Frankfurt am Main and Göttingen, and of the land and the city of Berlin. The day after his death, the Max Planck Society published the following obituary notice in all the major newspapers:

"On 28 July, in his 90th year, our Honorary President Otto Hahn passed away. His name will be recorded in the history of humanity as the founder of the atomic age. In him Germany and the world have lost a scholar who was distinguished in equal measure by his integrity and personal humility. The Max Planck Society mourns its founder, who continued the tasks and traditions of the Kaiser Wilhelm Society after the war, and mourns also a good and much loved human being, who will live in the memories of all who had the chance to meet him. His work will continue. We remember him with deep gratitude and admiration."

Legacy[link]

Otto Hahn on a stamp of the German Democratic Republic, 1979

Proposals were made at different times, first in 1971 by American chemists, that the newly syntheticized element no. 105 should be named Hahnium in Hahn's honour, although in 1997 the IUPAC (International Union of Pure and Applied Chemistry) finally named it Dubnium, after the Russian research center in Dubna (see element naming controversy). Although element 108 was given the name Hassium by its officially-recognised German discoverers in 1992, a 1994 IUPAC committee recommended that it be named Hahnium (Hn),^[22] in spite of the long-standing convention to give the discoverer the right to suggest a name. This recommendation was not adopted, following protests from the German discoverers, and the name Hassium (Hs) was adopted internationally in 1997.^[23]

In 1964 the only European and one of the world's four nuclear-powered civilian ships, the freighter NS Otto Hahn, was named in his honour. In 1959 there were the opening ceremonies of the "Otto Hahn Institute" in Mainz and the "Hahn Meitner Institute for Nuclear Research (HMI)" in Berlin. There are craters on Mars and the Moon, and the asteroids No. 3676 ("Hahn") and No. 19126 ("Ottohahn") named in his honour, as well as the "Otto Hahn Prize" of both the German Chemical and Physical Societies, the Otto Hahn Medal of the Max Planck Society and the "Otto Hahn Peace Medal in Gold" of the United Nations Association of Germany (DGVN) in Berlin.

A great many cities and districts in the German speaking countries have named secondary schools of all types after him, and countless streets, squares and bridges throughout Europe bear his name. Several states have honoured Otto Hahn by issuing coins, medals and stamps (among them the Federal Republic of Germany, the German Democratic Republic, Austria, Romania, Moldova, Angola, Cuba, the Commonwealth of Dominica, Madagascar, St. Vincent & the Grenadines, Chad, Ghana, Somalia, Guinea and Bissau). An island in the Antarctic (near Mt. Discovery) was also named after him, as were two Intercity trains of the German Federal Railways in 1971, running between Hamburg and Basel SBB, and the "Otto Hahn Library" in Göttingen. In 1974, in appreciation of the special contribution of Otto Hahn to German-Israeli relations, a wing of the Weizmann Institute of Science in Rehovot, Israel, was given the name "Otto Hahn Wing", and a scientific research center of the St. Louis University in Baguio (Philippines) was named the "Otto Hahn Building". In several cities and districts Otto Hahn busts, monuments and memorial plaques were unveiled, including Albstadt-Tailfingen, Berlin (East and West), Boston (USA), Frankfurt am Main, Göttingen, Gundersheim, Mainz, Marburg, Munich (in the hall of honour in the Deutsches Museum), Rehovoth (Israel), San Vigilio (Lake Garda, Italy), Springe and Vienna (in the foyer of the International Atomic Energy Agency, IAEA). There are public "Otto Hahn Centers" in Göttingen and Ottobrunn (near Munich), and planned in the next future also in Hahn's native city Frankfurt/Main. - A special honour in 1997 was conferred on Hahn in the Netherlands: after an azalea already bore his name (Rhododendron luteum var Otto Hahn), Dutch rose growers named a new variety of rose "Otto Hahn". Since several years a coffee-shop and restaurant in the city center of Rotterdam bears the name "Café Otto Hahn" (www.ottohahn.com). And also a cocktail "Otto Hahn", created in the 1950s, is still popular today: two equal parts of Whisky and Sherry, mixed together and served in a hot Cognac-glass.

At the end of 1999 the German newsmagazine FOCUS published an inquiry of 500 leading natural scientists, engineers and physicians about the most important scientists of the 20th century. In this poll the experimental chemist Otto Hahn - after the theoretical physicists Albert Einstein and Max Planck - was elected third (with 81 points) and thus the most significant empiric researcher of his time. (FOCUS, No. 52, 1999, p. 103-108).

Publications[link]

• 1936. Applied Radiochemistry. Cornell University Press, Ithaca, New York 1936. Humphrey Milford, London 1936. Oxford University Press, Oxford 1936.
• 1950. New Atoms - Progress and some memories. Edited by W. Gaade. Elsevier Inc., New York-Amsterdam-London-Brussels.
• 1966. A Scientific Autobiography. Introduction by Glenn T. Seaborg. Translated and edited by Willy Ley. Charles Scribner's Sons, New York. British edition: McGibbon and Kee, London 1967.
• 1970. My Life. Preface by Sir James Chadwick. Translated by Ernst Kaiser and Eithne Wilkins. Macdonald & Co., London. American edition: Herder and Herder, New York 1970.

See also[link]

• Hahn Meitner Institute (HMI), Berlin
• Otto Hahn Prize
• Otto Hahn Medal
• Otto Hahn Peace Medal
• German inventors and discoverers
• Fajans-Paneth-Hahn Law

References[link]

Bibliography[link]

• Berninger, Ernst H. (1970). Otto Hahn 1879–1968. (English ed.). Bonn: Inter Nationes. 
• Beyerchen, Alan D. (1977). Scientists under Hitler. New Haven and London: Yale University Press. 
• Bernstein, Jeremy (2001). Hitler's Uranium Club: The Secret recordings at Farm Hall (2nd ed.). New York, NY: Springer-Verlag. ISBN 0-387-95089-3 
• Clarke, Ronald C. (1980). The Greatest Power on Earth. London: Sidgwick & Jackson. 

• Anthony Feldman, Peter Ford, 1979: Otto Hahn - in: Scientists and Inventors. Aldus Books, London.
• Laura Fermi, 1962. The Story of Atomic Energy. Random House, New York.
• Hans D. Graetzer, David L. Anderson, 1971. The Discovery of Nuclear Fission. A documentary history. Van Nostrand-Reinhold, New York.
• Alwyn McKay, 1984. The Making of the Atomic Age. Oxford University Press.
• Klaus Hoffmann, 2001. Otto Hahn - Achievement and Responsibility. Springer, New York-Berlin-Barcelona-Hong Kong-London-Milan-Paris-Singapore-Tokyo.
• Horst Kant, 2002. Otto Hahn and the Declarations of Mainau and Göttingen. Berlin.
• Lise Meitner, 2005. Recollections of Otto Hahn. S. Hirzel. Stuttgart.
• David Nachmansohn, 1979. German-Jewish Pioneers in Science 1900–1933. Highlights in Atomic Physics, Chemistry and Biochemistry. Springer Inc., New York etc.
• R. W. Reid, 1969. Tongues of Conscience. Constable & Co., London.
• J.A. Revill, Sir Charles Frank, eds., 1993. Operation Epsilon. The Farmhall Transcripts. IOP Publishing, Bristol-Philadelphia.
• Richard Rhodes, 1988. The Making of the Atomic Bomb. Simon and Schuster, New York.
• Glenn T. Seaborg, 1972. Nuclear Milestones. San Francisco.
• William R. Shea, ed., 1983. Otto Hahn and the Rise of Nuclear Physics. Reidel, Dordrecht-Boston-Lancaster.
• Jim Whiting, 2004. Otto Hahn and the Discovery of Nuclear Fission. Mitchell Lane, Hockessin.
• Longden, Sean (2009). T-Force - The Race for Nazi Weapon Secrets, 1945. Constable. ISBN 978-1-84529-727-5.. 

External links[link]

Wikimedia Commons has media related to: Otto Hahn

Wikiquote has a collection of quotations related to: Otto Hahn

• Annotated bibliography for Otto Hahn from the Alsos Digital Library for Nuclear Issues
• Biography of Otto Hahn (German)
• Biography of Otto Hahn (German)
• Biography

Enrico Fermi
Enrico Fermi (1901–1954)
Born	(1901-09-29)29 September 1901 Rome, Italy
Died	28 November 1954(1954-11-28) (aged 53) Chicago, Illinois, USA
Citizenship	Italy (1901–1954) United States (1944–1954)
Fields	Physics
Institutions	Scuola Normale Superiore University of Göttingen Leiden University University of Florence Sapienza University of Rome Columbia University University of Chicago
Alma mater	Scuola Normale Superiore
Doctoral advisor	Luigi Puccianti
Doctoral students	Edoardo Amaldi Owen Chamberlain Geoffrey Chew Mildred Dresselhaus Jerome I. Friedman Marvin Leonard Goldberger Tsung-Dao Lee Ettore Majorana James Rainwater Marshall Rosenbluth Arthur H. Rosenfeld Emilio Segrè Jack Steinberger Sam Treiman
Other notable students	Richard Garwin Bruno Pontecorvo Leona Woods
Known for	New radioactive elements produced by neutron irradiation Controlled nuclear chain reaction, Fermi–Dirac statistics Theory of beta decay
Influenced	James Grier Miller
Notable awards	Matteucci Medal (1926) Nobel Prize for Physics (1938) Hughes Medal (1942) Franklin Medal (1947) Rumford Prize (1953)
Spouse	Laura Fermi
Signature

Enrico Fermi (Italian pronunciation: [enˈriko ˈfermi]; 29 September 1901 – 28 November 1954)^[1] was an Italian-born, naturalized American physicist particularly known for his work on the development of the first nuclear reactor, Chicago Pile-1, and for his contributions to the development of quantum theory, nuclear and particle physics, and statistical mechanics. He was awarded the 1938 Nobel Prize in Physics for his work on induced radioactivity.

Fermi is widely regarded as one of the leading scientists of the 20th century, highly accomplished in both theory and experiment.^[2] Along with J. Robert Oppenheimer,^[3] he is frequently referred to as "the father of the atomic bomb".^[4][5] He also held several patents related to the use of nuclear power.

Several awards, concepts, and institutions are named after Fermi, such as the Enrico Fermi Award,^[6] the Enrico Fermi Institute, the Fermi National Accelerator Laboratory, the Fermi Gamma-ray Space Telescope, the Enrico Fermi Nuclear Generating Station, a class of particles called fermions, the synthetic element fermium, and many more.

Biography[link]

Early years[link]

Enrico Fermi was born in Rome to Alberto Fermi, a Chief Inspector of the Ministry of Communications, and Ida de Gattis, an elementary school teacher of unusual intelligence.^[7] As a young boy, he shared his interests with his older brother, Giulio. They dismantled small engines and other parts. When Giulio died unexpectedly of a throat abscess in 1915, Enrico was distraught, and immersed himself in scientific study to distract himself. According to his own account, each day he would walk in front of the hospital in which Giulio died until he was inured to the pain.

One of the first sources for the study of physics was a book found at the local market of Campo de' Fiori in Roma. The 900-page book, titled Elementorum physicae mathematicae, written in Latin by Jesuit Father Andrea Caraffa, a professor at the Collegio Romano, covered subjects like mathematics, classical mechanics, astronomy, optics, and acoustics. Notes found in the book indicate that Fermi studied it intensely. Later, Enrico befriended another scientifically inclined student named Enrico Persico, and the two worked together on scientific projects such as building gyroscopes and measuring the Earth's magnetic field. Fermi's interest in physics was further encouraged by Adolfo Amidei, a friend of his father, who gave him several books on physics and mathematics, which he read and assimilated quickly.

Scuola Normale Superiore in Pisa[link]

In 1918, Fermi enrolled at the Scuola Normale Superiore in Pisa. In order to enter the Institute, candidates had to take a difficult entrance exam which included an essay. The given theme was Specific characteristics of Sounds (Italian: Caratteri distintivi dei suoni).^[8] The 17-year-old Enrico Fermi chose to derive and solve the partial differential equation for a vibrating rod, applying Fourier analysis. The examiner, Prof. Giuseppe Pittarelli, interviewed Fermi and concluded that his entry would have been commendable even for a doctoral degree. Enrico Fermi achieved first place in the classification of the entrance exam.

During his years at the Scuola Normale Superiore, Fermi teamed up with a fellow student named Franco Rasetti with whom he would indulge in light-hearted pranks and who would later become Fermi's close friend and collaborator. Besides attending the classes, Enrico Fermi found the time to work on his extracurricular activities, particularly with the help of his friend Enrico Persico, who remained in Rome to attend the university.

In Pisa, Fermi was advised by the director of the physics laboratory, Luigi Puccianti, who acknowledged that there was little that he could teach Fermi, and frequently asked Fermi to teach him something. Fermi's knowledge of quantum physics reached such a high level that Prof. Puccianti asked him to organize seminars about that topic. During this time he learned tensor calculus, a mathematical instrument invented by Gregorio Ricci and Tullio Levi-Civita, and needed to demonstrate the principles of general relativity. Between 1919 and 1923, Fermi studied general relativity, quantum mechanics, and atomic physics.

In 1921, his third year at the university, he published his first scientific works in the Italian journal Nuovo Cimento: the first was titled: On the dynamics of a rigid system of electrical charges in translational motion; the second: On the electrostatics of a uniform gravitational field of electromagnetic charges and on the weight of electromagnetic charges. At first glance, the first paper seemed to point out a contradiction between the electrodynamic theory and the relativistic one concerning the calculation of the electromagnetic masses. After one year with a work entitled Correction of severe discrepancy between electrodynamic theory and the relativistic one of electromagnetic charges. Inertia and weight of electricity, Enrico Fermi showed the correctness of his paper. This last publication was so successful that it was translated into German and published in the famous German scientific journal Physikalische Zeitschrift.

In 1922, he published his first important scientific work in the Italian journal I Rendiconti dell'Accademia dei Lincei entitled "On the phenomena occurring near a world line", where he introduces for the first time the so-called "Fermi coordinates", and proves that when close to the time line, space behaves as a euclidean one. In July of that year, Fermi submitted his doctoral thesis Un teorema di calcolo delle probabilità ed alcune sue applicazioni (A theorem on probability and some of its applications) to the Scuola Normale Superiore and received his Laurea from there at the unusually young age of 21.

In 1923, while writing the appendix for the Italian edition of the book The Mathematical Theory of Relativity by A. Kopff, Enrico Fermi pointed out, for the first time, that hidden inside the famous Einstein equation (E = mc²), there was an enormous amount of nuclear potential energy to be exploited.

In 1924, Fermi spent a semester at the University of Göttingen with Max Born, and then stayed for a few months in Leiden with Paul Ehrenfest. From January 1925 to the autumn of 1926, he stayed at the University of Florence. In this period, he wrote his work on the Fermi–Dirac statistics.

Professor in Rome[link]

Aged 24, Fermi took a professorship at the University of Rome (one of the first three in theoretical physics in Italy) ^[9] which he won in a competition whose selection committee was chaired by Professor Orso Mario Corbino, director of the Institute of Physics. ^[9] Corbino helped Fermi in selecting his team, which soon was joined by notable minds like Edoardo Amaldi, Bruno Pontecorvo, Franco Rasetti and Emilio Segrè. For the theoretical studies only, Ettore Majorana also took part in what was soon nicknamed "the Via Panisperna boys" (after the name of the street where the Physics Institute was). The group went on with its now famous experiments, but in 1933 Rasetti left Italy for Canada and the United States, Pontecorvo went to France and Segrè left to teach in Palermo.

Enrico Fermi and his students (the Via Panisperna boys) in the courtyard of Rome University's Physics Institute in Via Panisperna, about 1934. From Left to right: Oscar D'Agostino, Emilio Segrè, Edoardo Amaldi, Franco Rasetti and Enrico Fermi

During their time in Rome, Fermi and his group made important contributions to many practical and theoretical aspects of physics. These include the theory of beta decay, later referred to as the theory of the "weak interaction" (one of the 4 basic forces in nature, then brand new) with the inclusion of the neutrino postulated in 1930 by Wolfgang Pauli, and the discovery of slow neutrons, which was to prove pivotal for the working of nuclear reactors. His group systematically bombarded elements with slow neutrons, and during their experiments with uranium, narrowly missed observing nuclear fission. At that time, fission was thought to be improbable if not impossible, mostly on theoretical grounds. While people expected elements with higher atomic number to form from neutron bombardment of lighter elements, nobody expected neutrons to have enough energy to actually split a heavier atom into two light element fragments. However, the chemist Ida Noddack had criticised Fermi's work and had suggested that some of his experiments could have produced lighter elements. At the time, Fermi dismissed this possibility on the basis of calculations.

Fermi was well known for his simplicity in solving problems.^[10] He began his inquiries with the simplest lines of mathematical reasoning, then later produced complete solutions to the problems he deemed worth pursuing. His abilities as a great scientist, combining theoretical and applied nuclear physics, were acknowledged by all. He influenced many physicists who worked with him, such as Hans Bethe, who spent two semesters working with Fermi in the early 1930s. From the time he was a boy, Fermi meticulously recorded his calculations in notebooks, and later used them to solve many new problems that he encountered based on these earlier known problems.

When Fermi submitted his paper on beta decay^[11] to the prestigious journal Nature, the journal's editor turned it down because "it contained speculations which were too remote from reality". Thus Fermi saw the theory published in Italian and in German before it was published in English. Nature eventually did publish Fermi's report on beta decay on January 16, 1939.

Fermi remained in Rome until 1938.

Manhattan Project[link]

The Chicago Pile Team, including Fermi (bottom left), and Leó Szilárd (second from right on bottom)

In 1938, Fermi received the Nobel Prize in Physics 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 reactions brought about by slow neutrons". After Fermi received the Nobel Prize in Stockholm, he, his wife Laura, and their children emigrated to New York. This was mainly because of the Manifesto of Race promulgated by the fascist regime of Benito Mussolini in order to bring Italian Fascism ideologically closer to German Nazism. The new laws threatened Laura, who was Jewish. Also, the new laws put most of Fermi's research assistants out of work. Soon after his arrival in New York, Fermi began working at Columbia University, where he had already given summer lectures in 1936 (preface to Thermodinamics, Dover Publications, Inc. NY).

In December 1938, the German chemists Otto Hahn and Fritz Strassmann sent a manuscript to Naturwissenschaften reporting they had detected the element barium after bombarding uranium with neutrons;^[12] simultaneously, they communicated these results to Lise Meitner. Meitner, and her nephew Otto Robert Frisch, correctly interpreted these results as being nuclear fission.^[13] Following an advice of George Placzek, Frisch confirmed this experimentally on 13 January 1939.^[14][15]

Fermi's ID badge photo from Los Alamos

Meitner's and Frisch's interpretation of the work of Hahn and Strassmann crossed the Atlantic Ocean with Niels Bohr, who was to lecture at Princeton University. Isidor Isaac Rabi and Willis Lamb, two Columbia University physicists working at Princeton, heard the news and carried it back to Columbia. Rabi said he told Enrico Fermi; Fermi gave credit to Lamb. Bohr soon thereafter went from Princeton to Columbia to see Fermi. Not finding Fermi in his office, Bohr went down to the cyclotron area and found Herbert L. Anderson. Bohr grabbed him by the shoulder and said: “Young man, let me explain to you about something new and exciting in physics.”^[10] It was clear to a number of scientists at Columbia that they should try to detect the energy released in the nuclear fission of uranium from neutron bombardment. On 25 January 1939, a Columbia University team conducted the first nuclear fission experiment in the United States,^[16] which was done in the basement of Pupin Hall; the members of the team were Herbert L. Anderson, Eugene T. Booth, John R. Dunning, Enrico Fermi, 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 The George Washington University and the Carnegie Institution of Washington. There, the news on nuclear fission was spread even further, which fostered many more experimental demonstrations.^[10]

While at Columbia during World War II, Fermi and his wife resided in Leonia, New Jersey.^[17]

Fermi then went to the University of Chicago and began studies that led to the construction of the first nuclear pile Chicago Pile-1.

Fermi recalled the beginning of the project in a speech given in 1954 when he retired as President of the American Physical Society:

"I remember very vividly the first month, January, 1939, that I started working at the Pupin Laboratories because things began happening very fast. In that period, Niels Bohr was on a lecture engagement at the Princeton University and I remember one afternoon Willis Lamb came back very excited and said that Bohr had leaked out great news. The great news that had leaked out was the discovery of fission and at least the outline of its interpretation. Then, somewhat later that same month, there was a meeting in Washington where the possible importance of the newly discovered phenomenon of fission was first discussed in semi-jocular earnest as a possible source of nuclear power."^[18]

Drawings from the Fermi–Szilárd "neutronic reactor" patent

In August 1939 Leó Szilárd prepared and Albert Einstein signed the famous letter warning President Franklin D. Roosevelt of the probability that the Nazis were planning to build an atomic bomb. Because of Hitler's September 1 invasion of Poland, it was October before they could arrange for the letter to be personally delivered. Roosevelt was concerned enough that the Uranium Committee was assembled, and awarded Columbia University the first nuclear power funding of US$6,000. However, due to bureaucratic fears of foreigners doing secret research, the money was not actually issued until Szilárd implored Einstein to send a second letter to the president in the spring of 1940.

The money was used in studies which led to the first nuclear reactor — Chicago Pile-1, a massive "atomic pile" of graphite bricks and uranium fuel which went critical on December 2, 1942. The pile was built in a squash court under Stagg Field, the football stadium at the University of Chicago, as part of a secret project code-named the Metallurgical Laboratory^[19]. (Due to a mistranslation, Soviet reports said Fermi's work was performed in a converted "pumpkin field" instead of a "squash court",^[20] a mis-translation based on confusion between dual meanings of "squash", the food-crop plant and the game.)

This experiment was a landmark in the quest for energy, and it was typical of Fermi's brilliance. Every step had been carefully planned, every calculation meticulously done. When the first self-sustained nuclear chain reaction was achieved, one of the physicists, Arthur Compton, made a coded phone call to James Conant, chairman of the National Defense Research Committee. The conversation was in impromptu code:

Compton: The Italian navigator has landed in the New World.

Conant: How were the natives?

Compton: Very friendly.^[21]

This successful initiation of a chain-reacting pile was important not only for its help in assessing the properties of fission — needed for understanding the internal workings of an atomic bomb — but also because it would serve as a pilot plant for the massive reactors which would be created in Hanford, Washington, which would then be used to produce the plutonium needed for the bombs used at the Trinity site and Nagasaki. Eventually Fermi and Szilárd's reactor work was folded into the Manhattan Project.

To continue the research where it would not pose a public health hazard, the reactor was disassembled and moved to a wooded site outside Chicago, where Fermi directed research on reactors and other fundamental sciences. The name of the lab was Argonne Laboratory, which grew into the first of the U.S. national laboratories.^[19]

Fermi moved to what was to become Los Alamos National Laboratory in the later stages of the Manhattan Project to serve as a general consultant. He was sitting in the control room of the Hanford B Reactor when it first went critical in 1944. His broad knowledge of many fields of physics was useful in solving problems that were of an interdisciplinary nature. He became a naturalized citizen of the United States of America in 1944.

Fermi was present as an observer of the Trinity test on July 16, 1945. Engineer Jack Aeby saw Fermi at work:

As the shock wave hit Base Camp, Aeby saw Enrico Fermi with a handful of torn paper. "He was dribbling it in the air. When the shock wave came it moved the confetti. He thought for a moment."

Fermi had just estimated the yield of the first nuclear explosion. It was in the ball park.^[22]

Fermi's strips-of-paper estimate was ten kilotons of TNT; the actual yield was about 19 kilotons.^[23]

The FERMIAC, an analog device invented by Enrico Fermi to implement studies of neutron transport.

In 1947, Fermi invented the FERMIAC, an analog computer that used the Monte Carlo Method to study neutron transport through fissionable materials.

Post-war work[link]

The sign at Enrico Fermi Street in Rome

In Fermi's 1954 address to the American Physical Society (APS) he also said, "Well, this brings us to Pearl Harbor. That is the time when I left Columbia University, and after a few months of commuting between Chicago and New York, eventually moved to Chicago to keep up the work there, and from then on, with a few notable exceptions, the work at Columbia was concentrated on the isotope separation phase of the atomic energy project, initiated by Booth, Dunning and Urey about 1940".

Fermi was widely regarded as the only physicist of the 20th century who excelled both theoretically and experimentally.^[2] The well-known historian of physics, C. P. Snow, says about him, "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's ability and success stemmed as much from his appraisal of the art of the possible, as from his innate skill and intelligence. 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 which 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'.

Fermi's most disarming trait was his great modesty, and his ability to do any kind of work, whether creative or routine. It was this quality that made him popular and liked among people of all strata, from other Nobel Laureates to technicians. Henry DeWolf Smyth, who was Chairman of the Princeton Physics department, had once invited Fermi over to do some experiments with the Princeton cyclotron. Walking into the lab one day, Smyth saw the distinguished scientist helping a graduate student move a table, under another student's directions. Another time, a Du Pont executive made a visit to see him at Columbia. Not finding him either in his lab or his office, the executive was surprised to find the Nobel Laureate in the machine shop, cutting sheets of tin with a big pair of shears.

After the war, Fermi served for a short time on the General Advisory Committee of the Atomic Energy Commission, a scientific committee chaired by J. Robert Oppenheimer which advised the commission on nuclear matters and policy. After the detonation of the first Soviet fission bomb in August 1949, he, along with Isidor Rabi, wrote a strongly worded report for the committee which opposed the development of a hydrogen bomb on moral and technical grounds. But Fermi also participated in preliminary work on the hydrogen bomb at Los Alamos as a consultant, and along with Stanislaw Ulam, calculated that the amount of tritium needed for Edward Teller's model of a thermonuclear weapon would be prohibitive, and a fusion reaction could not be assured to propagate even with this large quantity of tritium.

Fermi was among the scientists who testified on Oppenheimer's behalf at an AEC hearing in 1954. The hearing resulted in denial of Oppenheimer's security clearance.

In his later years, Fermi did important work in particle physics, especially related to pions and muons. He was also known to be an inspiring teacher at the University of Chicago, and was known for his attention to detail, simplicity, and careful preparation for a lecture. Later, his lecture notes, especially those for quantum mechanics, nuclear physics, and thermodynamics, were transcribed into books which are still in print.

He also mused about a proposition which is now referred to as the "Fermi Paradox". This contradiction or proposition is this: that with the billions and billions of star systems in the universe, one would think that intelligent life would have contacted our civilization by now.

While he came from a Roman Catholic family and was baptized, he later on became an agnostic.^[24]

Toward the end of his life, Fermi questioned his faith in society at large to make wise choices about nuclear technology. He said:^[25]

"Some of you may ask, what is the good of working so hard merely to collect a few facts which will bring no pleasure except to a few long-haired professors who love to collect such things and will be of no use to anybody because only few specialists at best will be able to understand them? In answer to such question[s] I may venture a fairly safe prediction.

History of science and technology has consistently taught us that scientific advances in basic understanding have sooner or later led to technical and industrial applications that have revolutionized our way of life. It seems to me improbable that this effort to get at the structure of matter should be an exception to this rule. What is less certain, and what we all fervently hope, is that man will soon grow sufficiently adult to make good use of the powers that he acquires over nature."

Fermi died at age 53 of stomach cancer in Chicago, Illinois, and was interred at Oak Woods Cemetery. Two of his graduate students who assisted him in working on or near the nuclear pile also died of cancer. Fermi and his team knew that such work carried considerable risk but they considered the outcome so vital that they forged ahead with little regard for their own personal safety.^[26]

As Eugene Wigner wrote: "Ten days before Fermi had died he told me, 'I hope it won't take long.' He had reconciled himself perfectly to his fate".

Impact and legacy[link]

Spray paint mural of Enrico Fermi in the city of Vitoria, Spain