Lise Meitner’s career as a scientist spanned most of the heroic age of atomic physics, from the discovery of radioactivity in 1896 to the discovery of atomic fission in 1938. Born in Vienna in 1878, she spent her working life in Berlin, where Einstein called her “our Marie Curie.” Her life became tragic when the Nazis drove her from all she had lived for; and the dropping of the atomic bomb on Hiroshima made her realize that her passionate devotion to atomic physics had prepared the way for a weapon of unimagined destructiveness.
She came from a liberal Jewish family in Vienna—her father was a lawyer—and she grew up in what she herself described as a remarkably stimulating intellectual atmosphere. Toward the end of the last century and until the First World War Vienna had one of the world’s leading medical schools and a renowned university. It was also a lively center of literature, music, and the arts. To illustrate the city’s intellectual ferment, Meitner’s new biographer Ruth Sime mentions Sigmund Freud, Viktor Adler, and Theodor Herzl, but neither Adler, a socialist leader, nor Herzl, a founder of Zionism, contributed much to the life of Vienna itself. She fails to mention Gustav Mahler or Arthur Schnitzler, or Otto Wagner and Adolf Loos, the two great pioneers of modern architecture, or Josef Hoffmann and Koloman Moser, who founded the Wiener Werkstätte, the group that largely originated modern design. Sime deplores the views of Karl Lueger, Vienna’s anti-Semitic mayor, but she fails to note that Emperor Franz Josef was a philo-Semite who appointed Mahler director of the Vienna Opera at the age of only 37 and elevated many prominent Jews or men of Jewish descent to the nobility, among them the fathers of the philosopher Ludwig Wittgenstein and of the poet Hugo von Hofmannsthal.
Lise Meitner was determined from an early age to become educated like the men around her, but higher education was barred to girls, whose public schooling ended at the age of fourteen. Undeterred, she found private tutors to help her pass the entry exams for the University of Vienna, where she began the study of mathematics and physics. She had the good luck to be taught by Ludwig Boltzmann, one of the greatest physicists of all time.
At the beginning of the century the study of radioactivity was the most exciting subject in physics. Ten years after its discovery, when Meitner started her research, it was known that radium emitted three different kinds of radiation: alpha rays, which were positively charged helium nuclei shot out of the nuclei of radium atoms at a speed of more than 9000 miles a second; beta rays, which were negatively charged electrons; and gamma rays, which were electromagnetic waves like X-rays, only more penetrating. Meitner began research on alpha rays in Vienna, but after Boltzmann had killed himself in a fit of depression she decided to continue her studies in Berlin. She intended to stay for a few semesters, and remained for thirty-one years.
At first she just attended lectures, but in 1907 she met the young chemist Otto Hahn, and they decided to study radioactivity together. They asked the famous chemist Emil Fischer for space in his laboratory, but he would tolerate no women there, and reluctantly allowed Meitner to install herself in the wood workshop in the basement, provided she did not set foot anywhere else. To go to the toilet, she had to make her way to the nearest café.
She lived frugally with support from her father, but for her, as for Marie Curie, science was a vocation for which she was prepared to suffer penury. On return from a summer vacation in 1908, Meitner had herself christened into the Lutheran faith, inspired, Sime suggests, by the example of the great physicist Max Planck, who personified the German Protestant ideal of “excellent, reliable, incorruptible, idealistic and generous men, devoted to the service of Church and State”; for Church and State she would have substituted Science.
Hahn and Meitner were the same age. They not only shared an interest in radioactivity, but their skills complemented each other’s. Hahn was an accomplished chemist, but lacked knowledge of physics and mathematics, while Meitner was a physicist inexperienced in chemistry. They soon made their names with the discovery of two new radioactive elements and of two different mechanisms leading to the emission of beta rays.1 In their relations with each other, Meitner and Hahn never deviated from the strict Victorian code for relations between the sexes: they addressed each other as Fräulein Meitner and Herr Hahn, and avoided eating or going out for a walk together, signs of intimacy that might have invited gossip. It took sixteen years and the post-First World War revolution before they called each other Lise and Otto and used the familiar du. Neither of them was paid a salary until 1912, when Hahn was made a member of the newly founded Kaiser Wilhelm Institute for Chemistry and Meitner became assistant to Planck. In 1913 she, too, became a member of the Institute, but at first at a salary below Hahn’s.
When war broke out in August 1914 Meitner rushed to Vienna. She was carried away by the patriotic fervor of the crowds as they saw the eager young soldiers, including her own brothers, off to the front, and by the excitement of the early German victories. Despite her strong moral convictions, her letters show no evidence that she questioned the morality of the Austrian attack on Serbia or of the German invasion of Belgium. Hahn expected a quick German victory. But her enthusiasm evaporated when, working as an X-ray technician and nurse behind the lines on the Russian front, she came face to face with the severely wounded and dying young soldiers. In 1916 she was transferred to the Italian front and then back again to the Russian one. Feeling useless there, she returned to Berlin, where she was soon promoted to be head of the physics section of the Kaiser Wilhelm Institute with a salary equivalent to Hahn’s. In 1919 she became a full professor. Her academic career does not seem to have been seriously hampered either by her sex or by her being born Jewish.
Hahn and Meitner succeeded in isolating an important new radioactive element, protactinium, which others had failed to find. She became one of the stars in Berlin’s galaxy of great physicists, which included Albert Einstein, Max Planck, Max von Laue, James Franck, and later Erwin Schrödinger. All the same, she remained diffident. She wrote to Hahn: “Did I write to you that Irecently gave a colloquium on our work, and that Planck, Einstein, and Rubens [the professor of experimental physics] told me afterwards how good it was? From which you can see that I gave quite a decent lecture, even though I was, stupidly enough, again very self-conscious….”
In the nineteenth century each chemical element was believed to consist of only a single kind of atom, but radioactivity soon showed that certain elements consist of a mixture of atoms of slightly different weights; these were called isotopes. It was also considered impossible to turn one kind of chemical element into another; but radioactive elements were found to transform themselves spontaneously into a succession of different, slightly lighter elements. For example, the heaviest element then known, uranium, is a mixture of isotopes that are 238, 235, and 234 times the weight of a hydrogen atom, the lightest of the elements. Uranium 238 disintegrates into a succession of lighter elements, one of which is radium, whose radioactivity becomes reduced every 1690 years to half of its original value.
In Cambridge, England, Ernest Rutherford first achieved an artificial transmutation of elements by bombarding nitrogen with alpha particles from radium. This turned each atom of nitrogen into a heavier atom of oxygen, plus one lighter atom of hydrogen. Alpha particles penetrated and transformed lightweight atoms carrying nuclei with few positive charges; but being positively charged, they were repelled by the multiple positive charges of heavy nuclei like that of uranium.
In 1932 James Chadwick in Rutherford’s Cambridge laboratory discovered the neutron, a particle with the same weight as a proton, the nucleus of a hydrogen atom, but without its positive charge. Enrico Fermi in Rome realized that neutrons would not be repelled by atomic nuclei, however strongly charged. He irradiated all the chemical elements with neutrons, transmuting them into other elements and creating a great many new radioactive ones.2 When he bombarded uranium with neutrons, he produced a complex mixture of radioactive elements, some of which Fermi thought he had identified as new ones heavier than uranium, which he called transuranes.
Hahn and Meitner were skeptical of one of Fermi’s results and decided to reinvestigate it, together with the gifted young chemist Fritz Strassmann. In their experiments, the irradiation of uranium with neutrons produced three separate series of radioactive elements, some of which they also believed to represent transuranes.
This work was in full swing when Hitler incorporated Austria into the German Reich in March 1938. Until then Meitner’s Austrian citizenship had protected her from the Nazi laws; now one of her colleagues denounced her as a Jew whose presence endangered the Kaiser Wilhelm Institute, and her position there became untenable. Several foreign colleagues invited her to work abroad, but she hesitated until a new law forbidding technical experts to leave Germany trapped her. Her Austrian passport was invalid and she was refused a German one.
In this ominous situation the Dutch physicist Dirk Coster persuaded the chief of the Dutch border guards to issue instructions to admit her without a valid passport. He traveled to Berlin, and on July 13, 1938, smuggled Meitner into Holland through a small, lightly guarded frontier station. To avoid suspicion, she crossed the border with two small suitcases and no more than the legal currency allowance, a derisory ten marks. When Hahn said goodbye to her, he gave her, for emergencies, a diamond ring he had inherited from his mother. On the train Coster kept it for her in his pocket. To his and Meitner’s disappointment, he failed to find her a job or even a small grant in Holland. But this saved her life, because the Nazis would have caught her there a few years later and sent her to Auschwitz. Instead, the Swedish physicist Manne Siegbahn offered her a place in his new Stockholm laboratory, which she accepted. Neutral Sweden proved a safe haven, but Meitner, now aged fifty-nine, found herself stranded, without money, equipment, or collaborators, in a country whose language she could not speak.
Meitner never married, nor does she ever seem to have had a lover, but she had a great talent for friendship, and in Berlin the Plancks, the Hahns, and the Laues, all anti-Nazis, treated her as part of their own families. Apart from Siegbahn, who had no use for her, the Swedes she met were neither inhospitable nor cold; yet without her friends and her work she felt forlorn, in her own words a “wind-up doll… with no real life in her.”
Before Meitner fled, she had discussed with Hahn and Strassmann a strange new radioactive element, discovered after irradiation of uranium with neutrons by Irène Curie, Marie’s daughter, and Pavel Savitch in Paris. A few weeks later Curie and Savitch reported that this element behaved chemically as if it were a radioactive isotope of lanthanum, an element of only a little more than half the weight of uranium, which could have formed only by the splitting of the irradiated uranium atoms. Hahn and Strassmann refused to believe this splitting had occurred and decided to repeat the work of Curie and Savitch. After irradiating a sample of uranium with neutrons, they detected traces of a radioactivity which behaved as if it came from elements chemically similar to radium, though its activity halved in hours rather than years. How could they isolate and identify the elements responsible for such behavior?
When faced with a problem of this kind, chemists used to add some compound of a known, non-radioactive element to their solution as a carrier. When it was made to precipitate, i.e., separate itself, from the solution as an insoluble salt, it would carry the unknown radioactivity along with it; and more refined methods would later separate the radioactivity from the carrier. Since the unknown activity behaved chemically like radium, they dissolved their irradiated uranium in acid and then added to the solution a salt of barium, a non-radioactive element chemically similar to, but much lighter than, radium. Precipitation of the barium as an insoluble salt did indeed carry the new radioactivity with it, leaving the uranium behind in solution. Had the radioactivity come from radium itself or an element similar to radium, Strassmann could now have separated it from barium, using a method pioneered years earlier by Marie Curie. But all his attempts at separation failed.
This implied, even though they could not yet believe it, that the uranium atom had broken into pieces, and that one of the pieces was a radioactive isotope of barium. Hahn later recalled that at this stage “the possibility of a breakdown of heavy atomic nuclei into various light ones was considered as completely excluded.” On October 25 he wrote to Meitner: “A great pity that you are not here with us to clear up the exciting Curie activity.” On November 13 they met in Copenhagen, where Meitner told him that the results made no physical sense and urged him to check them very carefully.
Strassmann now wondered if the traces of the new radioactive elements were just too small to be separated from barium. To test that objection, he added equally small traces of known chemical elements to the barium salt, but found no difficulty in separating them from barium. Still incredulous, he wondered if the particular salt (the chloride) of the new element which he had made just happened to be inseparable from the chloride of barium. So he transformed the barium chloride into five other barium salts in turn. Each time the radioactivity was transformed with the barium and in none of the salts could it be separated from barium salt, proving that it must be caused by radioactive isotopes of barium. This unique chemical identification of minute traces of a short-lived radioactive element was a remarkable feat. Lise Meitner once told me that no one else could have done it at that time.
Despite the incontrovertible evidence that the uranium atoms had split—a momentous event in the history of science—Hahn was still torn by doubts; he asked Meitner in a letter dated December 19 if there might not be an element heavier than barium, but with the same chemical properties, and added: “We know ourselves that [uranium] can’t actually burst apart into [barium]…. If there is anything you could propose that you could publish, then it would still in a way be work by the three of us”—a reference to the fact that a joint paper with a Jewish émigré was politically ruled out.
Two days later he wrote: “How beautiful and exciting it would be just now if we could have worked together as before. We cannot suppress our results, even if they are perhaps physically absurd. You see, you will do a good deed if you can find a way out of this.” On the same day Meitner wrote to Hahn that she found it hard to accept a complete rupture of the uranium nucleus, “but in nuclear physics we have experienced so many surprises, that one cannot unconditionally say: it is impossible.” Hahn wrote up the results for publication, concluding as follows:
As chemists the experiments we have briefly described force us to substitute for the [heavy] elements formerly identified as radium, actinium, thorium the [much lighter] elements barium, lanthanum and cerium, but as “nuclear chemists” close to physics we cannot yet take this leap which is contrary to all experience of nuclear physics. 3
On the other hand, Strassmann recalls that he had no such hesitations. 4 Hahn did not state explicitly that the presence of barium implied a break-up of the uranium nucleus into fragments, but this was clear to all who read the paper.
Shortly after receiving Hahn’s letter, Meitner set off to spend Christmas with her nephew, the young physicist Otto Robert Frisch, with friends on the west coast of Sweden. Frisch was then working in Niels Bohr’s Physics Institute in Copenhagen. In his memoirs, Frisch recalls that dramatic meeting:
When I came out of my hotel room after my first night in Kungälv I found Lise Meitner studying a letter from Hahn and obviously worried by it. I wanted to tell her of a new experiment I was planning, but she wouldn’t listen; I had to read that letter. Its content was indeed so startling that I was at first inclined to be sceptical. Hahn and Strassmann had found that those three substances [they had discovered] were not radium…[but] that they were isotopes of barium.
Was it just a mistake? No, said Lise Meitner; Hahn was too good a chemist for that. But how could barium be formed from uranium? No larger fragments than protons or helium nuclei (alpha particles) had ever been chipped away from nuclei, and to chip off a large number not nearly enough energy was available. Nor was it possible that the uranium nucleus could have been cleaved right across. A nucleus was not like a brittle solid that can be cleaved or broken; George Gamov had suggested early on, and Bohr had given good arguments that a nucleus was much more like a liquid drop. Perhaps a drop could divide itself into two smaller drops in a more gradual manner, by first becoming elongated, then constricted, and finally being torn rather than broken in two? We knew that there were strong forces that would resist such a process, just as the surface tension of an ordinary liquid drop tends to resist its division into two smaller ones. But the nuclei differed from ordinary drops in one important way: they were electrically charged, and that [owing to mutual repulsion of the positive charges] was known to counteract the surface tension.
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 [positive] charge of a uranium nucleus, we found, was indeed large enough to overcome the effect of the surface tension almost completely; so the uranium nucleus might indeed resemble a very wobbly, unstable drop, ready to divide itself at the slightest provocation, such as the impact of a single neutron.
But there was another problem. After separation, the two drops would be driven apart by their mutual electric repulsion and would acquire high speed and hence a very large energy…. Where could that energy come from? Fortunately Lise Meitner remembered the empirical formula for computing the masses of nuclei and worked out that the two nuclei formed by the division of a uranium nucleus together would be lighter than the original uranium nucleus by about one-fifth the mass of a proton. Now whenever mass disappears energy is created…and one-fifth of a proton mass was just equivalent to [the right energy]. So here was the source for that energy; it all fitted!5
Frisch’s account is too sober to make the reader grasp how staggering the result of their calculation turned out to be. He and Meitner used Einstein’s famous equation E = mc2 to calculate the energy equivalent to the loss of one fifth of a proton from one atom of uranium.6 This calculation showed that the splitting of one gram (1/28 of an ounce) of uranium would release as much energy as the burning of two and a half tons of coal.
Why had neither Hahn and Strassmann, nor Fermi, nor Curie and Savitch noticed this? They had merely inquired into the chemical nature of the new radioactive elements formed when uranium was irradiated with neutrons, and none of them knew as yet that they came from the isotope with 235 times the weight of a hydrogen atom, which makes up less than 1 percent of the bulk of uranium. Since only a tiny fraction of the atoms of the minuscule amounts of uranium used in their experiments had split, the violence of the splitting had gone unnoticed.
After his return to Copenhagen, Frisch set up an experiment designed to measure the force of the fragments shot out when he irradiated uranium with neutrons and confirmed that it was as great as predicted by his and Meitner’s calculations. It was a situation, unusual in research, that fitted Karl Popper’s ideas of the scientific method. The violence of the reaction had remained unnoticed without a hypothesis predicting it; and Frisch detected it by an experiment designed to falsify the hypothesis.
Meitner and Frisch sent two letters to the British journal Nature, one signed by both with their theoretical interpretation of Hahn and Strassmann’s results,7 and another written by Frisch alone describing his experiments.8 They pointed out that the new radioactivities which Fermi and the Berlin group had attributed to elements heavier than uranium had, with one exception, been products of the splitting of uranium into lighter elements. The exception later turned out to be a precursor of plutonium. What Curie and Savitch had called lanthanum was a product of the radioactive decay of a barium isotope, but this possibility had been too far from their thoughts.
Meitner and Frisch coined the term fission for the new phenomenon, in analogy with the term biologists used to describe the spontaneous division of yeast cells. They did not suggest that the enormous energy released by the reaction might supply man with limitless energy for an almost unlimited time. Nor did they mention the possibility of making an atomic bomb, although this would have been clear to any physicist reading their papers. Besides, such a statement would have been frowned upon in those days as sensationalism unworthy of true scientists. The papers appeared in February 1939. Meanwhile, Niels Bohr described Frisch’s experiment to a meeting of the American Physical Society, where it aroused so much excitement that even before Bohr had finished speaking, some physicists were hurrying back to their laboratories to repeat it. On February 7 Bohr, now at Princeton, sent a letter to the journal Physical Review,9 attributing fission to the rare isotope uranium 235 rather than the abundant uranium 238.
In March 1940, Frisch and Rudolf Peierls, working at the University of Birmingham in England, calculated that no more than one kilogram (2.2 pounds) of uranium 235 would be needed to make an atomic bomb. They also indicated exactly how the rare isotope uranium 235 could be separated from the abundant uranium 238 and how it could be detonated. Their secret memorandum on their results set in motion the making of the bomb which destroyed Hiroshima.10 In the summer of 1941, Peierls engaged the German-born physicist Klaus Fuchs to help him with further theoretical work on the atomic bomb project. He did not realize until eight years later that Fuchs was a devoted Communist and had passed copies of all their work, including the Peierls-Frisch memorandum, to the Soviet Embassy in London, where it was collected by the NKVD case officer for technical intelligence, Vladimir Barkovsky. Barkovsky, now aged eighty-two, recounted his experience at a meeting held in Dubna, near Moscow, in May 1996, where he referred to Fuchs as “a hero who did the world great service,” but in England people thought otherwise. Barkovsky stressed that Fuchs was not paid.11
Meitner was shattered when she realized that the hypothesis on the transuranes underlying her last four years’ work in Berlin had now been disproved and that her departure from Germany had excluded her from the great discovery to which her work had led. The fact that she and Frisch had been the first to realize and publish the implications of Hahn and Strassmann’s discovery was no consolation to her. Nor was she consoled when Americans tended to quote her and Frisch’s papers in preference to Hahn and Strassmann’s, perhaps because they were written in English. She wrote to Hahn: “Now Siegbahn will gradually believe…that I never did anything and that you also did all the physics in Dahlem,” and to her brother: “Unfortunately I did everything wrong. And now I have no self-confidence, and when I once thought I did things well, now I don’t trust myself.” Perhaps she also reproached herself for having dismissed Curie and Savitch’s experiment rather than following it up. Her fears were confirmed when the Nobel Prize for chemistry for 1944 went to Hahn alone. Having been locked up in the Nobel Committee’s files these fifty years, the documents leading to this unjust award now reveal that the protracted deliberations by the Nobel jury were hampered by lack of appreciation both of the joint work that had preceded the discovery and of Meitner’s written and verbal contributions after her flight from Berlin.12
Because of the war, the jury was also hampered by lack of communication with the outside world. Hahn and Meitner had already been nominated jointly for their earlier discoveries and were again nominated jointly for their discovery of nuclear fission.But the Nobel Committee for chemistry ignored these nominations and confined its attention to Hahn and Strassmann’s two publications proving, by purely chemical methods, that irradiation of uranium with neutrons produced radioactive isotopes of barium. They never even considered including Strassmann, who had in fact done many of the experiments and introduced a crucial innovation while Hahn, a staunch anti-Nazi, was busy fending off Nazi attacks on himself and his institute. There was a proposal to award the physics prize to Meitner and Frisch at the same time as the chemistry prize to Hahn, but it went instead to the great theoretician Wolfgang Pauli, and later that proposal was crowded out by claims for other candidates.
Early in the war, Hahn told the young physicist Carl Friedrich von Weizsäcker: “If my discovery leads to Hitler obtaining an atomic bomb, I shall kill myself.” On hearing the news of Hiroshima, he really did want to kill himself, but his internment in England robbed him of the means, and his friend Max von Laue managed to calm him down. When Meitner was invited to join the team at Los Alamos, she refused, wanting to have nothing to do with building an atomic bomb. In August 1945, she was enjoying a quiet vacation in the Swedish countryside when a reporter called to tell her of Hiroshima. Shocked beyond words, she walked alone for many hours. Her friends had never seen her so distraught. Worse, reporters pursued her since she had suddenly become a public figure who shared responsibility for the atomic bomb. Under a headline FLEEING JEWESS, one news story described how she escaped from Germany with the secret of the bomb and handed it to the Allies.
In September 1945 Meitner wrote to her sister:
I feel like an impostor when American Jews…praise me especially because I am of Jewish descent. I am not Jewish by belief, know nothing of the history of Judaism and do not feel closer to Jews than to other people. And just now, when one wishes so strongly that all racial prejudices be eliminated from the world, isn’t it unfortunate if Jews themselves document such racial prejudice?
All the same, Meitner enjoyed her fame and the recognition she received in the postwar years in both Germany and the United States, and she reestablished friendly relations with her former Berlin colleagues and other leading physicists. After Einstein’s death in 1955 she wrote to Max von Laue: “For all my great admiration and affection for Einstein during the Berlin years I often stumbled inwardly over his absolute lack of personal relationships…. Only later did I understand that this separation from individuals was necessary for his love and responsibility toward humanity.” My own experience, on the contrary, is that people develop a love for humanity in general not because they deliberately turn their backs on personal relationships, but because they are incapable of forming them. Peter Med-awar told me about a colleague who loved all humanity, while the technician who worked for him could enter his room only at the risk of his life.
In 1960, aged eighty-two, Meitner moved to Cambridge to be with Otto Frisch and his family, and I was fortunate to get to know her. She showed no bitterness, and I admired her brilliance, her selfless passion for science, her warmth, and her sense of humor. In 1964, the US Atomic Energy Commission invited me to nominate a candidate for the prestigious Enrico Fermi Prize. I decided to nominate Meitner, but since I am not a physicist, I asked Sir Lawrence Bragg and Hans Bethe to support me. Hahn, who was also asked, nominated Strassmann. I was delighted when, in 1966, the Commission awarded the prize jointly to Meitner, Hahn, and Strassmann, which rectified to some extent the injustice of omitting Meitner and Strassmann from the Nobel Prize. Since Meitner was by then too frail to travel to Washington to receive the prize, Glenn Seaborg, the Commission’s chairman and discoverer of the true transuranes, came to Cambridge and presented it to her in a short ceremony at my house.
Ruth Sime accuses Hahn of belittling or ignoring Meitner’s contributions, but she does not give convincing evidence for her charges. Sime quotes Meitner’s letters written in Stockholm after the award of the Nobel Prize to Hahn in which she complains that he failed to mention their collaboration in his interviews with the press. This may have been true, but on the other hand, Hahn’s printed Nobel lecture gives Meitner full credit for all their joint work; the curriculum vitae appended to the lecture stresses the years and the topics of their collaboration.13 Hahn’s autobiography gives details of their work together and quotes the full texts of the crucial exchange of letters between them in December 1938.14
Frisch’s widow has assured me that in the years Meitner lived in Cambridge she never voiced anything but deep affection for Hahn; Manfred Eigen, a younger Nobel Laureate in chemistry, was struck by Hahn and Meitner’s manifestly warm friendship when he spent time with them in Göttingen in the 1960s. Weizsäcker writes that he never met anyone more decent and benevolent than Hahn. When Sime criticizes Hahn for boasting that physics had nothing to do with his and Strass-mann’s discovery, she fails to take into account that chemists of their generation learned little physics, which left them feeling inferior to physicists, whom they needed to interpret their experiments. A desire to compensate for that feeling, rather than any wish to belittle Meitner’s contribution, may have been the source of that boast. Sime also reports Hahn saying that he and Strassmann would not have made their discovery had Meitner stayed in Berlin. There is some truth in that, because she apparently discounted Curie and Savitch’s results as spurious and not worth bothering about.
Sime’s accounts of Meitner’s and her colleagues’ scientific work are accurate, readable, and intelligible to anyone with a rudimentary knowledge of physics and chemistry. She gives a vivid picture of the life and personality of this remarkable woman, illustrating Peter Medawar’s dictum:
It is high time [laymen] recognized…the misleading and damaging belief that scientific inquiry is a cold dispassionate enterprise, bleached of imaginative qualities, and that a scientist is a man who turns the handle of a machine of discovery; for at every level of endeavour scientific research is a passionate undertaking, and the Promotion of Natural Knowledge depends above all else on a sortie into what can be imagined but is not yet known.15
Strassmann deserves to be mentioned as a quiet hero of the story Sime has reconstructed, and not only because he did many of the crucial experiments. When he was unemployed in the 1930s he preferred to starve rather than accept a job that would have required him to join the Nazi Party. During the war, he and his wife hid the Jewish pianist Andrea Wolffenstein in their apartment for several months at the risk of their lives. Wolffenstein survived and Strassmann was honored at the Israel Holocaust Museum over forty years later as one of the many Germans who refused to collaborate with the Nazis.
Meitner died in 1968, a few months after her old friend and colleague Otto Hahn.
February 20, 1997
They found that some beta rays were emitted by radioactive nuclei directly, while others were knocked out of the surrounding shell of electrons by gamma rays. ↩
Fermi used a glass vial filled with beryllium powder and radon as his neutron source. ↩
O. Hahn and F. Strassmann, “Uber den Nachweis und das Verhalten der bei der Bestrahlung des Urans mittels Neutronen entstehenden Erdalkalimetalle,” Die Naturwissenschaften, January 6, 1939, pp. 11-15. ↩
Fritz Strassmann, Kernspaltung (Berlin, 1938; privately reprinted in Mainz, 1978). ↩
Otto Frisch, What Little I Remember (Cambridge University Press, 1979), pp. 115-116. ↩
In this equation E stands for energy, m for mass, and c for the velocity of light. ↩
L. Meitner and O.R. Frisch, “Disintegration of Uranium by Neutrons: a New Type of Nuclear Reaction,” Nature, February 11, 1939, pp. 239-290. ↩
O.R. Frisch, “Physical Evidence for the Division of Heavy Nuclei under Neutron Bombardment,” Nature, February 18, 1939, p. 276. ↩
N. Bohr, “Resonance in Uranium and Thorium Disintegration and the Phenomenon of Nuclear Fission,” Physical Review, February 15, 1939, pp. 418-419. ↩
This memorandum was later published in Margaret Gowing’s book Britain and Atomic Energy, 1939- 1945 (St. Martin’s, 1964). ↩
Thomas Reed and Arnold Kramish, “Trinity at Dubna.” In Physics Today, “Special issue: new light on early Soviet atomic bomb secrets,” November 1996, p. 32. ↩
See E. Crawford, R. Lewin Sime, and M. Walker, “A Nobel tale of wartime injustice,” Nature, August 1, 1996, pp. 393-395; and C.F. von Weizsäcker and J.H.J. Oelering, “Hahn’s Nobel was well deserved,” Nature, September 26, 1996, p. 294. ↩
O. Hahn, “From the natural transmutations of uranium to its artificial fission,” in Nobel Lectures in Chemistry 1942-1962 (Elsevier, 1964). ↩
Otto Hahn, Mein Leben (Munich: F. Bruckmann, 1968). ↩
Peter Medawar in The Times Literary Supplement, October 25, 1963, p. 850. ↩