The Physicist Who Explained Fission: Lise Meitner and the Nobel She Never Got

In the Deutsches Museum in Munich there is a plain wooden workbench crowded with small instruments: valves, batteries, a tangle of wiring and counters. In 1938 that equipment was not on one table at all. At the Kaiser Wilhelm Institute for Chemistry in Berlin it was spread across three separate rooms, one for irradiating samples, one for measuring them and one for the chemistry. With it, the chemists Otto Hahn and Fritz Strassmann found something they could not explain: when they fired neutrons at uranium, barium came out.

The person who explained it was not in the building. She was not even in the country. Lise Meitner, Hahn’s partner of three decades, had fled Nazi Germany five months earlier with two small suitcases and 10 marks in her purse. Over Christmas 1938, walking through a snowy Swedish wood with her nephew, she worked out that the uranium nucleus had split in two and released an enormous amount of energy. Her nephew gave the process its name: fission.

Hahn alone received the Nobel Prize for it. Meitner was nominated 49 times over four decades, for chemistry and for physics, and never won. She died on 27 October 1968, 58 years ago this week. Her name now sits on the periodic table, on a statue in Berlin and on an IAEA programme for women in the nuclear field. Here is how a physicist who began her Berlin career in a basement wood shop came to explain the most consequential reaction of the 20th century, and how she was written out of it for so long.

A doctorate in Vienna

Elise Meitner was born in Vienna in November 1878, the third of eight children of the chess master Philipp Meitner, one of the first Jewish lawyers admitted to practice in Austria, and his wife Hedwig. Vienna’s university did not admit women until 1897, and the entrance exam demanded schooling that girls could not get, so she prepared privately and in July 1901 passed the external school-leaving exam. Only four of the fourteen women who sat it that year passed. One of the others was Henriette Boltzmann, daughter of the physicist Ludwig Boltzmann.

Meitner entered the University of Vienna that October and fell under Boltzmann’s spell. She spoke for the rest of her life about the enthusiasm of his lectures. Her doctorate was awarded on 1 February 1906, making her the second woman to earn a physics doctorate at Vienna. Within a year she had done an experiment on how alpha particles scatter off metal foils, finding that the scattering grew with the mass of the metal atoms. It was one of the results that pointed Ernest Rutherford toward the nuclear atom.

In Vienna, a woman with a physics doctorate could expect to become a schoolteacher. With her father’s financial backing, Meitner went to Berlin in 1907 to look for real research. Max Planck, who was on record as opposing women at universities in general, invited her to his home and let her attend his lectures. She became friends with his twin daughters, who shared her love of music.

The woman in the wood shop

On 28 September 1907, at a physics colloquium, Meitner met a young chemist almost exactly her age. Otto Hahn had trained with William Ramsay in London and Ernest Rutherford in Montreal, and had come back to Berlin to hunt for new radioactive substances. The organic chemists around him did not think detecting invisible traces of isotopes by their radiation was real chemistry. He needed a physicist. She needed a laboratory.

The laboratory they got was a former woodworking shop in the basement of Emil Fischer’s Chemical Institute. Women were not yet admitted to Prussian universities, and Meitner was allowed into the wood shop only by its own outside entrance. She could not go upstairs to the rest of the building, including Hahn’s other lab space. If she needed a toilet, she had to use the one at a restaurant down the street. She was unpaid, living on an allowance from her father, and officially she was a “guest.”

The restrictions eased when Prussia admitted women to university in 1908, and her career inched forward. Planck, fearing she might go back to Vienna, made her his assistant, her first paid job and the first time a woman had held the post of scientific assistant in Prussia. In 1912 she and Hahn moved into the new Kaiser Wilhelm Institute for Chemistry in the leafy Berlin suburb of Dahlem.

Radioactive contamination was the enemy of measurements that delicate. Hahn and Meitner ran their new laboratories under strict rules: chemical and physical measurements in different rooms, no shaking hands for anyone handling radioactive material, and rolls of toilet paper hung beside every telephone and door handle so nobody touched them with bare fingers. It was a far cry from the factory floor in New Jersey where, in the same years, young women were licking radium paint off their brushes.

Thirty years of firsts

During the First World War Meitner served as an X-ray nurse with the Austrian army while Hahn was in a German chemical-warfare unit. Back in Berlin in 1917, she was made head of her own physics section at the institute, and she and Hahn went after a puzzle left over from before the war: what element was the “mother” of actinium? The answer was a new element, number 91. Meitner named it protoactinium, later shortened to protactinium, and when the British chemists Frederick Soddy and John Cranston reported the same isotope in 1918 they acknowledged her priority.

Her firsts kept coming. In 1922 she became the first woman in Prussia to gain the habilitation in physics, the qualification that allowed her to lecture at a university. She had already published more than 40 papers, so she was excused the thesis, but Max von Laue insisted she still give an inaugural lecture because he wanted to hear what she would say. Its title was “Problems of Cosmic Physics.” In 1926 she became an extraordinary professor, the first woman physics professor at a German university.

Her own research had moved to beta decay. In 1922 she explained why atoms sometimes shed electrons with characteristic, “signature” energies, an effect now called the Auger-Meitner effect after her and the French physicist Pierre Auger, who found it independently a year later. Her careful measurements of beta rays also fed one of the great puzzles of the time: the electrons came out with a spread of energies, as if energy were not conserved. In 1930 Wolfgang Pauli addressed an open letter to Meitner and Hans Geiger proposing that an unseen, neutral particle was carrying away the missing energy. Enrico Fermi later named it the neutrino.

Einstein reportedly called her “the German Marie Curie.” Between 1924 and 1948 she was nominated for the Nobel Prize in Chemistry 19 times, and from 1937 she began to collect physics nominations too.

Escape with ten marks

Meitner was Austrian, and of Jewish descent, though she had converted to Lutheranism and been baptized in 1908. When Hitler came to power in 1933 her foreign citizenship and her long service protected her job at the institute for a time, even after she was dismissed from her university teaching post. Then, on 12 March 1938, Germany annexed Austria. Her Austrian passport was suddenly worthless, and she was effectively a German Jew with no way to leave legally. James Franck offered to sponsor her emigration to the United States, and Niels Bohr offered a place in Copenhagen, but Denmark would not accept her Austrian passport.

The rescue was organized by Dutch physicists, led by Dirk Coster. On the evening of 12 July 1938 Meitner stayed at the institute until 8 p.m., correcting a colleague’s paper as if nothing were happening. Hahn and the editor Paul Rosbaud helped her pack two small suitcases with summer clothes, and Hahn gave her a diamond ring he had inherited from his mother, to sell in an emergency. She spent the night at Hahn’s house.

The next morning she and Coster boarded a train on a lightly used line to the Dutch border at Bad Nieuweschans and crossed without incident; the German guards may have taken her for a professor’s wife. She later said that she left Germany forever with 10 marks in her purse. Wolfgang Pauli sent Coster a telegram saying he was now “as famous for the abduction of Lise Meitner as for the discovery of hafnium.”

She ended up in Stockholm, at Manne Siegbahn’s new physics institute, on the offer of a one-year position, with some laboratory space and none of the technicians or equipment she had relied on for twenty years. In Berlin, Hahn and Strassmann kept going with the experiment the three of them had started.

A letter at Christmas

That experiment grew out of Fermi’s work in Rome. In 1934 Fermi’s group had fired neutrons at uranium and seen new radioactivities, which they took to be “transuranic” elements heavier than uranium. Meitner, Hahn and Strassmann spent four years chasing those products and found a great many of them, all of which they too took to be transuranic. One chemist, Ida Noddack, suggested in 1934 that the nucleus might instead have broken into large fragments. Nobody followed it up.

In late 1938 Hahn and Strassmann tried to separate what they thought were isotopes of radium from their irradiated uranium. They used barium as a carrier and expected to split the two apart. It would not work. On 19 December Hahn wrote to Meitner that the “radium” behaved chemically like barium. Barium has an atomic mass about 40 percent smaller than uranium’s, and no known kind of radioactive decay could knock that much off a nucleus.

Meitner wrote back at once, cautious but not dismissive: “At the moment the assumption of such a thoroughgoing breakup seems very difficult to me, but in nuclear physics we have experienced so many surprises, that one cannot unconditionally say: ‘It is impossible.'” She trusted Hahn’s chemistry. Hahn and Strassmann did not wait for more. They sent their paper to the journal Naturwissenschaften on 22 December, ending it with a nervous half-step: as chemists they should replace the symbols for radium, actinium and thorium with barium, lanthanum and cerium, but as “nuclear chemists” close to physics they could not yet bring themselves to take that step.

A walk in the snow

Meitner was spending Christmas with her friend Eva von Bahr in the small town of Kungälv, north of Gothenburg, and she had asked her nephew, the physicist Otto Robert Frisch, to join her from Copenhagen. Frisch arrived wanting to talk about his own experiment. She wanted to talk about Hahn’s letter. They went out into the snowy woods, Frisch on skis and his aunt on foot, insisting she could keep up.

The idea they reached for was Bohr’s “liquid drop” model, which pictured the nucleus not as a hard ball but as a drop of fluid held together by something like surface tension. A big enough drop, set wobbling, might stretch, pinch in at the waist and divide. Frisch later described the moment they stopped walking:

At that point we both sat down on a tree trunk (all that discussion had taken place while we walked through the wood in the snow, I with my skis on, Lise Meitner making good her claim that she could walk just as fast without), and started to calculate on scraps of paper.

The numbers worked. Uranium’s large electric charge was almost enough on its own to overcome the surface tension, so a uranium nucleus really could be a wobbly, unstable drop, ready to divide when a single neutron struck it. The two halves would then fly apart under their mutual electrical repulsion with about 200 million electron volts of energy. Where did that energy come from? Meitner worked out that the two fragments would be lighter than the original nucleus by about a fifth of a proton’s mass. Through Einstein’s E=mc², a fifth of a proton mass is about 200 MeV. Everything fitted.

Two hundred million electron volts per atom is tiny in everyday terms, but it is millions of times more energy per atom than any chemical reaction releases. Their short note said nothing about the spare neutrons each split throws out, which can go on to split other nuclei. Within weeks physicists realized what that meant: a chain reaction was possible, the one that would later make a softball-sized sphere of plutonium so dangerous. Nature had found it long before physicists did: in Gabon, uranium ore ran its own chain reaction about two billion years ago.

“What idiots we have been!”

Back in Copenhagen in early January, Frisch told Bohr, who slapped his forehead and exclaimed, “What idiots we have been!” Bohr promised to keep quiet until they had a paper ready. Meitner and Frisch, now in different countries, worked out a one-page note for Nature over long-distance phone calls. They also designed a quick experiment to back it up: if the nucleus really split, the fragments should fly off with so much energy that a detector would register large pulses, far bigger than anything alpha particles produce.

Frisch ran the experiment on 13 January 1939 and saw exactly the pulses they had predicted. He still needed a name for the process. He asked William A. Arnold, an American biologist working in Copenhagen, what biologists called it when a living cell divides in two. Arnold said “fission,” and the word went into the paper. Frisch mailed both papers to Nature on 16 January. The joint note, “Disintegration of Uranium by Neutrons: a New Type of Nuclear Reaction,” appeared on 11 February 1939, and his paper on the recoil experiment a week later.

By then the news had already escaped. Bohr sailed for America in early January and arrived in New York on 16 January, where Léon Rosenfeld, who was traveling with him and did not know it was confidential, described it at a Princeton journal club. On 25 January a Columbia University group repeated the experiment in the basement of Pupin Hall, the first fission experiment in the United States. Fermi, who had won the 1938 Nobel Prize in Physics partly for those “transuranic” elements, had to add a footnote to his Nobel lecture: some of them had been fission products all along. On 1 September 1939, the day Germany invaded Poland, Bohr and John Wheeler published their theory of how fission works, built on the same liquid drop.

Hahn and Strassmann published their own second paper in February 1939 and gave the process its German name, Uranspaltung. Their papers did not acknowledge Meitner’s part in the discovery. In Nazi Germany, crediting a Jewish refugee was dangerous.

The prize that went to one name

The Nobel committees had nominations for Meitner from some of the best-known physicists alive, including Werner Heisenberg, Max von Laue, Arthur Compton, James Franck, Niels Bohr and Max Planck. After the war Hahn himself nominated Meitner and Frisch for the physics prize. In all, the Nobel archive records 49 nominations: 19 for chemistry between 1924 and 1948 and 30 for physics between 1937 and 1967.

The chemistry committee leaned on reports by The Svedberg and Arne Westgren, chemists who were impressed by Hahn’s work but felt that the experimental work of Meitner and Frisch was not extraordinary. In 1944 the committee voted to recommend Hahn alone. Germans had been forbidden by their own government to accept Nobel Prizes since the Peace Prize went to the pacifist Carl von Ossietzky in 1936, and the Royal Swedish Academy of Sciences put the 1944 chemistry prize off for a year. In 1945 it went to Hahn alone, “for his discovery of the fission of heavy nuclei.” Hahn read about it in a newspaper while interned at Farm Hall in England with nine other German scientists.

The physics committee was no kinder. Its reports on Meitner and Frisch were written by Erik Hulthén, a student of Manne Siegbahn, who argued that theory deserved a prize only when it inspired great experiments, and whose assessment leaned on pre-war papers. Siegbahn, the committee chairman, disliked Meitner, and three of the committee’s five members, Siegbahn among them, came from Siegbahn’s own school of X-ray spectroscopy.

Meitner’s own verdict was generous. In a letter to a friend on 20 November 1945 she wrote: “Surely Hahn fully deserved the Nobel Prize in chemistry. There is really no doubt about it. But I believe that Otto Robert Frisch and I contributed something not insignificant to the clarification of the process of uranium fission – how it originates and that it produces so much energy.” Years later she praised Hahn and Strassmann’s “fantastically good chemistry that nobody else could do at that time.”

When the committee records were unsealed decades later, the historians Elisabeth Crawford, Ruth Lewin Sime and Mark Walker went through them. Writing in Physics Today in 1997, they concluded that her exclusion “may well be summarized as a mixture of disciplinary bias, political obtuseness, ignorance, and haste.” It is a familiar pattern for women in science in those years: on this site we have told the stories of Cecilia Payne-Gaposchkin, whose discovery of what stars are made of was slow to win acceptance, and Henrietta Leavitt, whose law for measuring the universe outlived her.

Nothing to do with a bomb

Meitner understood the military meaning of fission as quickly as anyone. When she was invited to join Frisch on the British contribution to the Manhattan Project at Los Alamos, she refused: “I will have nothing to do with a bomb!” She said the atomic bombings of Hiroshima and Nagasaki came as a surprise to her, and that she was “sorry that the bomb had to be invented.”

She was just as hard on herself. “It was not only stupid but very wrong that I did not leave at once,” she wrote of her years in Germany after 1933. And she was hard on old friends. In June 1945 she drafted a letter to Hahn, which he never received: “You all worked for Nazi Germany. And you did not even try passive resistance.” Their friendship survived; they remained close friends after the war.

Woman of the Year

In January 1946 Meitner arrived in the United States for a lecture tour and found herself a celebrity. The Women’s National Press Club named her its Woman of the Year, and at the dinner she sat next to President Harry S. Truman. She attended a party for General Leslie Groves, who had run the Manhattan Project and who, in his 1962 memoir, would give her sole credit for discovering fission. She spent part of that spring as a visiting professor at the Catholic University of America in Washington.

She disliked public speaking, especially in English, and had no taste for fame. She turned down a visiting professorship at Wellesley College and went back to Sweden, where she moved to the Royal Institute of Technology in Stockholm in 1947. There she worked with Sigvard Eklund on R1, Sweden’s first nuclear reactor. She became a Swedish citizen in 1949, keeping her Austrian citizenship by special act of parliament.

Late honors

In 1960 Meitner retired and moved to England, where many of her relatives lived, settling in Cambridge. Recognition came slowly but did come. In 1966 the U.S. Atomic Energy Commission gave the Enrico Fermi Award jointly to Hahn, Strassmann and Meitner, the first time it had gone to anyone who was not American and the first time to a woman. The wording of the diplomas was telling. Hers praised “extensive experimental studies leading to the discovery of fission.” His said “culminating in.”

The ceremony was held at the Hofburg palace in Vienna, but Meitner was too ill to travel, so Frisch accepted on her behalf. Glenn Seaborg, the discoverer of plutonium, presented the award to her in person on 23 October 1966 at the Cambridge home of Max Perutz, the Austrian-born chemist who had once helped Britain test an aircraft carrier made of ice.

Hahn died on 28 July 1968. Meitner, by then very frail, was not told. She died in Cambridge on 27 October 1968, at 89, and was buried in the village of Bramley in Hampshire, near her younger brother Walter. Frisch wrote the words on her headstone: “Lise Meitner: a physicist who never lost her humanity.”

Element 109 and a statue in Berlin

The longer view has been kinder than the Nobel committee. When Strassmann, the last survivor of the three, was asked about the discovery during the 1978 centenary celebrations, he asserted the importance of both his analytical chemistry and Meitner’s physics in the discovery. In August 1982 physicists at the GSI laboratory in Darmstadt created the first atoms of element 109. They proposed calling it meitnerium, and the name was officially adopted in 1997. Curium honors both Pierre and Marie Curie; meitnerium is the only element named solely for a real woman.

In October 2010 the Berlin building that had housed the Kaiser Wilhelm Institute for Chemistry, known since 1956 as the Otto Hahn Building, was renamed the Hahn-Meitner Building. In July 2014 a statue of Meitner was unveiled in the garden of Humboldt University, alongside statues of Hermann von Helmholtz and Max Planck, the professor who had once let her attend his lectures.

And her name is on a programme that might have pleased her more than any statue. Since 2023 the International Atomic Energy Agency’s Lise Meitner Programme has sent groups of women working in nuclear science and engineering on professional visits to nuclear facilities in host countries. Its eighth visit, to Russia in August 2026, brought the total to 115 women from 49 countries, with visits to France and Austria and the programme’s first visit to China next in line.

The woman who once had to use a restaurant toilet down the street because she was not allowed upstairs has become the name the nuclear world uses to open doors for other women. Hahn’s table is in a museum. Meitner’s explanation of what happened on it is in every physics textbook.

Further reading