To completely respect Lise Meitner, it’s a must to first overlook the whole lot you discovered concerning the atom in high school. Overlook that the nucleus is made up of impartial particles referred to as neutrons and constructive particles referred to as protons. Overlook that you understand that electrons stay in statistically decided chance clouds outdoors the nucleus. Overlook totally about how alpha decay ejects a Helium nucleus from the atom, and Beta decay permits neutrons and protons to vary forwards and backwards into one another to preserve stability.
All of these powerful commonplaces have been solely unknown to Meitner’s era till they took up the bafflingly difficult process of discovering them by means of sensible manipulations of magnetism, radiochemistry, and theoretical physics. That period, of cracking the atom, is suffering from scientific immortals: Bohr and Einstein, Heisenberg and Schrödinger, Fermi and Pauli, and the theoretician of nuclear fission, Lise Meitner (1878-1968).
The mythology of Meitner is a sophisticated yarn basket of truths and obfuscations that historians of science have only started to untangle up to now few many years. In america, she was wildly common based mostly on a narrative that she stole Hitler’s nuclear bomb plans and smuggled them to the Allies, which was manifestly not true and embarrassed her completely every time it was brought up. Meanwhile, in Europe, her essential position in nuclear fission’s discovery was being slowly erased by a dedicated workforce of German chemists who needed to keep the credit for themselves as part of Germany’s post-war religious reconstruction. Lionized for what she didn’t do, and summarily punted out of what she did do, Meitner only acquired something like proper approval for her many accomplishments in the direction of the top of her lengthy, irritating, exciting life.
As spectacular as her scientific profession was to develop into, it was very almost smothered at age fourteen. Meitner was an Austrian, and Austria was one of many decided latecomers to the thought of girls’s schooling. Up until the final years of the nineteenth century, public schooling for women merely ended at fourteen. At that age, your decisions have been both to attend for marriage or to find a personal educating position . Faculty taught women drawing and singing, however no math beyond what was needed to stability the housekeeping books. Meitner, who dearly beloved science and math from a young age, was confronted with the prospect of a profession as a French tutor as the summit of her hopes.
For seven crucial years, from 1892 when she completed the general public schooling a woman was allowed, to 1899, years when her male contemporaries have been learning all of the science they might eat, Meitner waited. Finally, in 1897 the federal government opened the schools to ladies, if they might move the Matura. Meitner raced to compensate for the seven years of schooling she had been forbidden and, in 1901, took the check that allowed her to lastly comply with her calling.
She handed, and attended the College of Vienna, the place she caught the bug for physics from Ludwig Boltzmann, a type of rare scientific geniuses who was additionally an incredible and approachable educator. He had not a stick of gender prejudice about him, and promoted Meitner’s studies with understanding and zeal.
It wasn’t in Austria, nevertheless, but in Berlin, underneath Max Planck (who was considerably extra skeptical about ladies’s capability to do science till Meitner proved him mistaken), that Meitner would report the string of discoveries that made her identify. She was interested in the mysteries of radioactivity, a area ripe with potential for a physicist wanting to know the character of atomic structure and nuclear stability. These studies, nevertheless, referred to as for sophisticated chemical separations that required the guiding hand of a grasp chemist. Meitner discovered hers in a fellow younger researcher named Otto Hahn.
For 3 many years, from 1907 to 1938, Hahn and Meitner have been an inseparable group, Hahn handling the tough chemical manipulations required to isolate radioactive substances while Meitner handled the arithmetic and physics of explaining the outcomes. In follow, Meitner dealt with as much of the chemical experimentation as Hahn did, however within the years of their closest collaboration, the breakdown of duties hardly mattered. They have been a staff that labored, and success rolled out of their lab at a gentle clip.
They started by categorizing totally different alpha and beta emitting substances with an eye fixed in the direction of locking down the similarities and variations between the 2 kinds of radiation. Within the strategy of doing that, they rediscovered an impact that may be crucial to all their future analysis, that of radioactive recoil, the place a nucleus, after ejecting an alpha particle, flies away from its father or mother substance, depositing as a movie on a nearby floor. Keep in mind that Harriet Brooks had discovered the effect previously, but its significance had gone unremarked until Meitner and Hahn rediscovered it and commenced using it as a option to separate radioactive substances from one another. Rutherford, ever Brooks’s advocate, wrote to Hahn stating that the impact had been noted by Brooks, however Hahn refused to concede her precedence.
This touchiness over priority should have troubled Meitner, but she and Hahn had different fish to fry. Particularly, with the coming of World Warfare I, and Hahn’s drafting into Germany’s poison fuel program, Meitner was left on her personal to divide her time between conflict work (which included volunteering as an x-ray technician on the entrance, inspired by the instance of Marie and Irene Curie) and persevering with the workforce’s research. Without considerable input from Hahn, she succeeded in the unspeakably high quality process of discovering a new component, protoactinium, a serious outcome which was however revealed with Hahn’s identify first.
Why Meitner launched a end result she obtained by herself with Hahn’s identify is unknown, and why she put his identify first is almost unfathomable, however it was an act of generosity that may come to hang-out her later, when Hahn’s apologists tried to characterize her as merely Hahn’s lab assistant, fairly than a full scientist in her personal right.
The warfare over, Hahn and Meitner needed to wrestle underneath the load of performing experiments while hindered by incorrect however plausible theories about how the atom is structured. Before 1932, when neutrons have been discovered, the perfect concept for a way the nucleus worked was based mostly on the thought of nuclear electrons, i.e. electrons that stay within the nucleus. We now know that the rationale a U-238 nucleus, for example, has a cost of +92 but a mass of 238 is because it has 92 protons and 238-92 = 146 neutrons. However without the neutrons, you may only assume that the nucleus had 238 protons, whose charge was introduced right down to 92 by the presence of 146 electrons within the nucleus.
Determining how Beta decay works when you will have a mannequin of the nucleus like that as your start line is a frightening process, made even worse by the truth that the electrons emitted during Beta decay seemed to have a continuous distribution of energies, which flew in the face of every little thing physics knew concerning the Conservation of Power. Meitner would spend much of the 1920s making an attempt to nail down precisely the order of occasions in Beta Decay, and for her rigorous work establishing the Beta sequence, she was made Germany’s first lady professor of physics in 1926.
As if that conundrum weren’t perplexing sufficient, the Thirties introduced an entire new vat of Puzzling to ponder over in the type of neutrons, positrons, and neutron impression events. There’s a ton of fascinating science that Meitner did during this era, including experiments with gamma scattering to find out how photons interact with matter, and her work that was the primary to discover positrons from a non-cosmic supply, however I have a sense the rationale you’re here is fission, so let’s get to it.
In 1934, Meitner had determined that the power of a neutron when it collides with a nucleus has a task to play as as to if that neutron is just captured or whether it punches an alpha particle out of the nucleus. That very same yr, Enrico Fermi, by means of neutron bombardment, appeared to have made the world’s first transuranium parts. The world rushed to verify the results, but difficulties arose in verifying the chemical status of the merchandise. What was recognized was that a neutron struck a component, and the outcome was a special factor, the idea being that it was the subsequent greater factor, or aspect 93. For 4 years, no one thought-about the likelihood that the product parts have been in truth much smaller fragments of the original uranium atom.
Meitner and Hahn worked on the venture of identifying the transuranium parts, doing what they might beneath the more and more oppressive shadow of Nazi Germany. Hahn, although not a member of the Nazi get together, was of “pure” racial lineage, but Meitner was of Jewish descent, and a lady, two issues that the Nazi administration couldn’t lengthy stand able of respect and authority. That she lasted in her submit as long as she did was largely a measure of the size of time she had been in her place, and her work in the course of the First World Struggle as a nurse and subject technician.
However the partitions have been closing. Meitner hesitated, not wanting to go away behind her work and her routine for untested waters, but by 1938 there was no extra hiding the fact that she needed to flee Germany as soon as potential. The government was rounding the flip from encouraging Jews to go away to making it unimaginable for them to take action, as part of the gearing up of the Remaining Answer. Meitner, as any person with technical experience, and any person with a world fame, was doubly forbidden to emigrate, lest she move on very important info to Germany’s rivals and discredit the German state, as Einstein had finished together with his emigration earlier. She had no selection but to illegally flee the nation, leaving her books, her furniture, and her work behind as she was snuck overseas by pals and aided by sympathetic border guards prepared to look the other method. She was sure for Sweden, her biggest discovery, and many years of frustration.
Her new publish was in Manne Siegbahn’s newly established nuclear laboratory, where she was given an empty area and left to her personal units, dwelling on a pittance in a small unfurnished room with nothing to wear besides the few articles of clothing she might gather up earlier than her flight. Siegbahn thought-about her an imposition, and was routinely and aggressively unhelpful in securing her the gear she wanted to do the barest of research. Her only solace was in advising Hahn and their assistant, Fritz Strassmann, on their transuranium research, pushing them to investigations that, as chemists, they have been unwilling to do, but that turned out to be essential to the discovery of nuclear fission. Their experiments have been turning up an element that appeared rather a lot much less like component 93 and a lot more like good previous barium, however they couldn’t deliver themselves to consider it, and repeatedly asked Meitner whether or not the outcomes made sense from a physics standpoint. Meitner, during a stroll together with her nephew, Otto Robert Frisch, labored out a model whereby the nucleus cut up, releasing power comparable to the difference in stability of the mother or father and daughter atoms, and found that the numbers labored out perfectly. Frisch coined the term “fission” for the method of an atom breaking into pieces, and the nuclear age was born.
At first, the priority was comparatively clear. Hahn, Meitner, and Strassmann had been working on the undertaking till Meitner was pressured to flee. Hahn and Strassmann continued the physical experiments, beneath Meitner’s remote steerage, which uncovered the very fact of fission, and Meitner’s grasp of physics offered the theoretical rationalization for the results. To any sane individual, fission was an interdisciplinary discovery to be credited to Hahn, Meitner, and Strassmann, with Frisch thrown in for those who have been feeling beneficiant about it.
However that’s not how Germany would keep in mind it. After the Second World Warfare, the German nuclear physicists have been gathered up by the Allies and stored underneath remark in an electronically bugged house. There, the myth was born that the Germans have been technically proficient sufficient to create an atomic bomb, but that they didn’t as a result of they have been too moral. It was an entire lie, and certainly one of its sub-stories was that the discovery of fission, which kicked off the entire nuclear age, was the doing of German chemistry alone, and belonged solely to Hahn and Strassmann.
After the conflict, Meitner was capable of finally return to analysis when, in 1947, she left Siegbahn’s lab to take up a place at the Royal Institute of Know-how. There, beginning anew at the age of 69, she studied the position that neutrons play in atomic stability, how heavy parts in addition to uranium capture neutrons, and how power released during fission relates to the dimensions of the fragments created. It was necessary work for the event of nuclear reactors and the theoretical understanding of fission, nevertheless it was marred by Hahn’s forceful makes an attempt, whereas sustaining ties of private friendship with Meitner, to exclude her from co-credit for fission, which he and Strassmann acquired a Nobel Prize for simply after the warfare.
Hahn was the lion of German science following World Struggle II, an enthralling and photogenic spokesperson for a Germany making an attempt to overlook its past and get on with the enterprise of turning into an financial and scientific superpower again. Analysis facilities and youngsters have been named after him. Lise Meitner died in 1968 just shy of her ninetieth birthday, honored bountifully as an individual by the nation that had accomplished her a lot mistaken, but not as a scientist. Great as Germany was rising, it was not midway great sufficient to think about her intellectually as something but Hahn’s loyal assistant.
Lead image: Lise Meitner around 1906 in Vienna by way of Wikipedia, public domain.
FURTHER READING: Otto Hahn’s A Scientific Autobiography (1962) is an fascinating read concerning the chemistry of early radioactivity studies, and a transparent instance of his unwillingness to provide the least credit score to Meitner for her half in fission’s discovery. As to biographies, I’ve talked earlier than about how nice Ruth Lewin Sime’s Lise Meitner: A Life in Physics is, notably within the element it goes into concerning the confusing rush of experimentation in the early days of radioactivity analysis. The concluding chapters get a bit samey-samey, but within the identify of publishing a narrative that had been vigorously suppressed for the higher part of 4 many years, I feel we will deal.
And for more superior Ladies in Science comics, take a look at the archive and my books, Illustrated Ladies in Science – Volume 1, 2 and three