Lise Meitner: Mother of the Atom Bomb

The following is an article from Uncle John's Supremely Satisfying Bathroom Reader

You've heard of physics J. Robert Oppenheimer, the "father of the A-Bomb." But have you head of Lise Meitner? Her discovery of nuclear fission opened the door to the creation of the atom bomb, much to her regret. Here's her story.

OUT OF SCHOOL

Lise Meitner [wiki] was born in 1878 in Vienna, Austria. She was very bright, but in those days it didn't matter--education was for boys only. People thought that if the delicate female brain was subjected to too much education, the result would be mental illness and infertility. (Schooling for girls ended at age 13.) Fortunately for Meitner in the 1890s, the Viennese government began to permit women to attend high school and college, making it possible for her to pursue her passion--physics. After graduating from the University of Vienna in 1906, Meitner went to Berlin to attend lectures by Max Planck, later winner of the Nobel Prize for his work in quantum mechanics. This existence of the atom had only recently been discovered and the study of radiation was new and exciting --and Berlin was where these sciences were being advanced most vigorously. She decided to stay.

A WOMAN'S PLACE

At the University of Berlin, Meitner had to ask permission to attend classes. Planck was reluctant to allow a woman in, but begrudgingly gave his permission, saying, "It cannot be emphasized strongly enough that Nature itself has designated for woman her vocation as mother and housewife, and that under no circumstances can natural laws be ignored without grave damage." Planck later recognized that Meitner had great talent, ad she became his assistant.

Eventually she was offered a position doing research…though she was not allowed to work in the same lab as the men and was instead given a makeshift workshop in the basement. Her parents supported her financially, but she wrote scientific articles to earn additional income, signing her name "L. Meitner." (Journals would not publish work written by a woman.) At the university, Meitner began working with another scientist, Otto Hahn. Together they made numerous discoveries about the nature of the atom and radiation. They remained scientific partners for the rest of their lives.

SECOND-CLASS CITIZENS

When the modern Kaiser-Willhelm Institute opened a new wing devoted to radiation research, Hahn was offered a job and Meitner accompanied him…officially listed as his "unpaid guest." (Hahn got paid for his work; she did not.) At the institute, Meitner discovered the element protactinium. Tough she did the majority of the work, Hahn's name appeared as senior author on their scientific papers.

Consequently, the Association of German Chemists presented him with their highest award, the Emil Fischer Medal. Meitner received only a copy of his medal. It was only after World War I that Meitner's value began to be recognized: She became the first woman professor ever in Germany and was finally paid a living wage (though still less than Hahn). In 1926 she was appointed full professor of physics at the University of Berlin. There, she continued to study beta and gamma rays, isotopes, atomic theory, radioactivity, and quantum physics.

A NEW COUNTRY

By 1937 Meitner and Hahn had identified at least nine different radioactive elements. A scientist named Fritz Strassmann joined them, and together the three of them began working to find out what happens when the nucleus of an atom splits. But at this time, the Nazis were raising to power. Meitner was forced to fill out papers admitting that her grandparents were Jewish. It didn't matter that she was raised a Protestant--she was fired from her job. Jews made up less than 1% of the German population, yet they accounted for 20% of the scientists. Researchers all over Germany began to follow Albert Einstein's lead, and fled the country.

Meitner announced that she was taking a "holiday," but instead escaped to safety in Sweden. At the age of 59, after living and working in Germany for 31 years, she was forced to leave her money, possessions, research papers, friends, and career. Starting over from scratch, she went to work at the Nobel Institute of Physics in Stockholm, where she spent the next 22 years. It was there that she made the discovery that literally rocked the world.

SPLIT DECISION

Scientists knew that radiation is released when the nucleus of an atom decays. Every nucleus has protons, which have a positive charge, and electrons, which have a negative charge. When a nucleus loses protons, radiation is emitted and the atom transforms into a new kind of atom. This new atom, or "daughter atom," splits and spirals away with enough force that the original atom recoils, like a rifle recoils after firing a bullet. (Radium releases a million times more energy during radioactive decay than when it is burned like coal.)

Then scientists discovered that every atom also has a neutron, which has no electrical charge at all. Enrico Fermi discovered that when he bombarded heavy elements that were even heavier than the ones he started with. Protons and neutrons in a nucleus cling very tightly together, but they cling more tightly in some elements than others. Iron is the most stable element and therefore the hardest to split. Uranium is the least stable and the easiest to split. When Meitner and Hahn had tried bombarding uranium with slow-speed neutrons, they ended up with barium--which is lighter than uranium, not heavier. They were confused: neither of them realized they had just split the atom.

EARTH-SHATTERING

In Sweden, Meitner discovered that when a nucleus splits, the mass of the two new atoms added together is less than that of the original atom, because some of the mass is released as energy. That energy is what causes the two pieces of the split atom to repel from each other. She calculated, using Einstein's formula of E=MC2, exactly how much energy would be given off every time a single atom split and predicted that this could happen in a chain reaction, releasing an enormous amount of energy in a very short period of time. If millions of atoms could be split at once, the power would be unimaginable: splitting the nucleus of a uranium atom, for example, releases 20 million times more energy than exploding an equal amount of TNT.

When she shared this news with Hahn, he did experiments to prove her theory. Then he published a paper (leaving her name off, for fear he would get in trouble if Nazis found he was still in contact with her). Meitner also published a report in a British journal in 1939. Suddenly the world was in a race to see who would be first to harness atomic energy in the form of a bomb. Einstein wrote a letter to President Roosevelt warning him about what would happen if Germany got the bomb first. Roosevelt set American scientists to work on the project--called the Manhattan Project--and invited Meitner to help. She turned the job down, repulsed by the idea that her discovery might be used to kill people. She told them she hoped they failed.

BAD CREDIT

The Nazis, in the meantime, had been removing all traces of the Jews, and Meitner's name was erased from all the research she had done. Perhaps because of this, Otto Hahn managed to convince himself--and the world--that the discovery of nuclear fission (Meitner coined the term) had been his. Hahn received the Nobel Prize in 1944. (Meitner never did.) For years, Hahn was listed at the inventor, with Lise Meitner occasionally mentioned as his assistant. When the atom bomb was dropped on Japan, Meitner was upset, not only by the devastation but also by the sudden publicity: reporters on her doorstep; cameras in her face; phone messages and telegrams waiting for her reply. She had little to say. The bomb had killed 100,000 people, and suddenly she was being portrayed in the media as the person who had come up with the blueprint for it.

RECOGNITION

Lise Meitner finally did receive her share of attention for her discoveries. She was named "Woman of the Year" by the Women's National Press Club; received the Max Planck Medal from the German Chemical Society; received honorary doctorates, published 135 scientific papers; won the Enrico Fermi Award; and was elected to the Swedish Academy of Science--only the third woman in history to achieve that honor. She was even offered a movie deal by MGM. (She turned it down, horrified that the script called for her to flee from Germany with an atom bomb hidden in her purse!)

Meitner continued her research into her mid-70s and helped Sweden design its first nuclear reactor, which was the way she wanted her discovery to be used. Despite continued exposure to massive amounts of radiation, she lived to be nearly 90 years old, dying in 1968, just three months after Otto Hahn. In 1992 physicists named the newly discovered 109th element in her honor: meitnerium.