Reading Lise Meitner: A Life in Physics

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 Reading Lise Meitner: A Life in Physics [U Cal Press;1996] by Ruth Lewin Sime.  The noble reason to read the book would be to learn the story of a woman and a Jew [secular] who accomplished great science but who was overlooked by the patriarchal and antisemitic societies of the time.

 

But reading it in fact because I'd like to learn something about the interaction and interdependence of experiment and theory in science. Yet, addressing the sexism and racism in her life and times is clearly inescapable.

 

The life of Lise Meitner is the choice because her work was intricate to the discovery of nuclear fission and the Atomic bomb. I knew bits of her story and wanted to know more. An   In Our Times Podcast provided special impetus. That's the context for the summer research undertaking.-JV

 

The story of the  nuclear bomb has been told by some very capable historians and participants. Richard Rhodes’ The Making of the Atomic Bomb, American Prometheus by Kai Bird and Martin J Sherwin and Leslie Groves’ Now It Can Be Told come to mind immediately.

 

Lise Meitner enters and exits most of these histories briefly and quietly – dare I say, like a ghostly radiation. Sime's book reveals her true centrality.

 

My view would have it that she was first to discover nuclear fission. But it's more complicated than that. She was a close colleague of Otto Hahn. He along with Fritz Strassman  like Hahn, a chemist in December 1938 bombarded Uranium with neutrons and discovered that barium -  a much lighter element - was produced. This was unexpected, because the reigning consensus  would have it that the element produced would be heavier.

Meitner, a physicist and expert experimentalist at that time had fled Germany. She was now in Sweden. She was still in touch with Hahn, and received a letter from him detailing the findings. 

 Together with her nephew Otto Frish, she provided theoretical explanation for these results, identifying that the Uranium nucleus had split into two  smaller nuclei. Frisch named the process 'fission.'

Here, Hahn did the experiment, but it was the team of Meitner and Frisch that explained what it was. It was Nuclear Fission. And they calculated how devastatingly powerful this could be. Hahn got the Nobel in Chemistry in 1944. Meitner, got nada. [Thanks to Science History.org ]

In fact, Meitner had a hand in designing the experiments along with Hahn, with whom she worked for 30 years. Before her exile to Sweden, she and Hahn, like others, bombarded bombarding uranium with neutrons thinking this would create "transuranium" elements that were heavy than uranium. It was an era of element-finding and element creation.

The word of Meitner’s explanation of Hahn’s experiment spread quickly.

In February 1939, Meitner and Frisch's "Disintegration of Uranium by Neutrons: a New Type of Nuclear Reaction," was published in Nature. The conclusions were amplified by Niels Bohr, who spoke on the topic in the U.S. Within weeks laboratories [including Fermi’s] began to confirm the process experimentally.  [Thanks to IAEA ]

 

This all happened in [what would now be called] a difficult geopolitical situation. Hitler’s Germany was fast moving toward violent repression and war. Physicists quickly grasped the military potential of this discovery of nuclear reactions.

This led to one of the most famous letters in world history. Refugee Physicists Leo Szilard, Eugene Wigner, Edward Teller approached Einstein, to convey the import of Hahn’s and Meitner’s discovery to Pres. Franklin Roosevelt. Einstein wrote a letter.

Scientists had conjectured on this. But this was the real goods. The picture of a refugee woman physicist’s Nature paper setting in motion the Atomic Age stuns. Yet, my interest in reading her biography is less world-shaking - it's centered on interest in experimentation and theorization as Meitner brilliantly accomplished it. After likely guiding Hahn in his experiment's set up, and then with her nephew calling on the work of Bohr and Einstein for insight, and calculating painstakingly the probable effects, she reached her startling synthesis.

 The basic quantum physics involved in this is beyond my kin. Truly, tho, the author Sime, in the spirit of Einstein, does a great job of keeping all that as simple as possible, but not – unfortunately for me - simpler. It is a history of science worth the reading.  

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In Sime's telling, Meitner’s path to achievement met numerous cultural obstacles. The family had come to Austria to escape the pogrom. They adapted in the vibrant scene of fin de siècle Vienna. Lise Meitner was born in 1878. Her father was a lawyer,  one of the first  Jewish lawyers admitted to the Austrian bar. Home schooled and supported for years by her father, she was one of the first women to attend the University of Vienna and receive a doctorate in Physics.

Despite the constant need to provide social context and scientific underpinnings, Sime’s story moves at a steady pace. Meitner goes to Berlin to audit classes in the male-dominated Institute led by Max Plank. She got some lab space and began work. Women were not allowed in the lab – the ostensible reason was that their hair was likely to catch fire. Lise found a carpenter’s workshop in the basement. When she heads to Berlin, she is still dependent on her parents for financial support.

She was determined – and the physicists were a comparatively nice bunch; nice to know and helpful. The engaging study in Berlin started with the beta particles. This work was interdisciplinary, a touchstone through Meitner’s career. She found a ready research partner in chemist Otto Hahn.

During a summer break in that first year (1908), she converted to the Evangelical Congregation of Protestantism. Her sisters had earlier converted to Catholicism. The author says that since Lise was totally excluded from a secured position by reasons of gender then viewing her conversion as an act to overcome antisemitism  is not likely reasonable. At such times – the discussion of ‘why Lise did not marry’ is another - the book glosses over matters that would bear more analysis today. Some present-day readers would be naturally disappointed in that.    

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Meitner's brilliance lay in her ability to both design experiments and interpret their results theoretically. She had a rare genius for bridging theory and practice.

Meitner had reached her analysis of nuclear fission as she matured into a steadily unfolding career. A constant theme: She rigorously combined the study of the daily annals, while actively applying novel instrumentation designs for new experiments. 

 It was in radioactivity that she began to gain prominence. The field of physics was teeming in Meitner’s days – what with the work on relativity, quantum mechanics and the structure of the atom. It wasn’t immediately the case that radioactivity - seen in X-Rays, radium and various phenomena -  was to be a prime focus, but it happened, and she was there. 

 Research into radioactivity gained her attention, and focus. This was a time when repeated discovery of new elements spurred overall momentum, but it took time to uncover and understand the nature of nuclear energy that radioactivity and, in turn, radiochemistry could unveil.

 Meitner kept up with the physics news on theory, and on experimentation. In the latter case, she was quick to try out colleagues’ tools and techniques such as mass spectrometry, Wilson Chambers [it could track the paths of alpha particles, she built the first such chamber in Berlin, connecting it to a photographic apparatus], mass spectrometers,   and Geiger counters. She didn’t invent mass spectroscopy, no. But she was in the forefront of its application, which was crucial to discovering isotopes and, in turn, measuring their mass and, eventually, understanding their role when released in fission. 

Lise Meitner didn't invent the Wilson cloud chamber—that was Charles Thomson Rees Wilson! However, she built experimental setups that coupled a cloud chamber with a stereoscopic camera to observe particles in motion. All in a long day’s work.

With Hahn and Fritz Strassman, she fashioned a  Geiger-Müller radioactivity counter used to measure the decay of radioactive substances produced by bombarding uranium with neutrons.

She and Hahn’s work on Radioactive Recoil – where a nucleus receives a measurable kick after emitting a particle – was measured with then-new laboratory equipment such as early electroscopes, which were used to measure alpha and beta particles as well as gamma rays. This work set the table for a long chain of breakthroughs based on studying particle decay. 

That is a small technical sampling, that shows something of the tools of analysis in the early nuclear era. A snapshot view of methodology as applied by the incredibly gifted and hardworking scientist, Lise Meitner. Unquestionably, the human story of Lise Meitner’s of determined struggle against prejudice toward women and persecution of Jews. With “Lise Meitner,” Ruth Lewin Sime adds measurably to historical understanding of this extraordinary scientist, and the lessons for today are striking.