Libby, Leona Marshall

views updated

Leona Marshall Libby

Leona Marshall Libby (1919–1986) was a founder of high-energy physics. She was also known as a pioneer in nuclear energy technology, and she discovered cold neutrons and researched isotope ratios. She was one of the only women who worked on the Manhattan Project, the project that created the nuclear reactor and built the first atom bomb.

Libby was born on August 9, 1919, in Le Grange, Illinois. She was born to Wreightstill Woods, a lawyer, and Mary Holderness Woods, a teacher, and was one of three girls and two boys raised on the family farm. When the depression hit in 1929, the family was hit hard and Libby's family struggled to make ends meet.

Interested in Chemistry

Libby had developed an early interest in chemistry and commenced studies rather quickly, she did not let her family's financial straits stop her from pursuing her education. Libby won a scholarship to go to college because of the quality of some of her early work, and then while she was attending her college classes, she worked twenty hours a week to pay for the part that her scholarship did not cover. She graduated in 1938, at age nineteen, from the University of Chicago with a Bachelor of Science degree. Her counselor at the time warned Libby that women in the field of science would most likely have a difficult time of it, as there were not many women accepted in the field at that time, and that she might starve if she continued on her path. Libby, however, luckily ignored the warning, and continued to pursue her goals single-mindedly. She persisted in her studies and eventually obtained her Ph.D. from the University of Chicago in 1943.

For her Ph.D., Libby studied quantum chemistry and diatomic molecular spectroscopy with Nobel Laureate Robert Mulliken. Diatomic molecular spectroscopy is the science of working with things made up of two atoms: a diatomic molecule, emphasizing the individual responses or structures of the behavior of these two molecules while dealing with the theory and interpretation of interactions between matter and radiation. Basically, it is concerned with the types and amounts of radiation produced by the combination of two molecules.

The Manhattan Project

While studying for her Ph.D., Libby also began working with Italian physicist Enrico Fermi. Fermi was involved in working on the first nuclear reactor at the Chicago Metallurgical Laboratory in Chicago's Manhattan District, and Libby was to become the first woman to join Fermi's team of scientists. Libby was chosen to be part of the project because her dissertation studies familiarized her with the vacuum technology needed to build the boron trifluoride counters that were required for the project. These counters were used to measure neutrons into piles of graphite and uranium blocks to create a chain reaction, a necessary step in producing atomic bombs. This project took shape before World War II because Germany was growing in strength and power. The scientists working on the project felt a sense of urgency as there was an ever-mindful fear that Germany might produce the bomb before the United States did. The project later became known as the Manhattan Project, which developed the first nuclear fission reactor in the world, called CP-1, and also helped build the first atomic bomb. Libby herself was in charge of constructing the neutron detectors. She was the only woman present at the first nuclear chain reaction, which took place under the football stands at the University of Chicago on December 2, 1942.

Libby was known to describe her workings on the Manhattan Project to her family as being akin to the science involved in the famous Buck Rogers television series. She and the other scientists were connected to a project that seemed so cutting edge at the time that it was almost from a different world. The scientists who collaborated on the Manhattan project worked so closely together that Libby came to consider them part of her family. But Libby was not only involved in her work, during leisure time, Libby could be found swimming in Lake Michigan almost daily during the summer months. She also built a true, personal friendship with Fermi, who was known to be consistent in his encouragement of young women. This was an especially important personality trait, as it was rare among the men of science to choose women to join them. For this and other reasons Libby and Fermi became fast friends.

Worked While Pregnant

While she was working on the project, Libby met her first husband, John Marshall, Jr. They married on July 3, 1943, and the couple eventually had two children. When she was pregnant with her first child she was afraid that she would be fired from the project, so she disguised it, wearing large overalls and shoving things into the pockets to camouflage her growing stomach. She worked up until just before she gave birth and returned a week later to the project to continue her work. In fact, Libby worked during both her pregnancies, something she was very proud of, because she said it proved that the nuclear technology they were all working on was not dangerous or harmful in the least. Whether or not that was true, Libby and her children suffered no ill effects from Libby's work during her pregnancies, and on the contrary Libby gained much admiration and respect from her fellow scientists for her unflagging dedication to the project.

In 1944, while World War II was still waging, Libby took the position of consulting physicist at the Hanford plutonium production reactor in Washington state. It was while she was there that America dropped the atomic bombs on Hiroshima and Nagasaki, although there is no record of what Libby might have thought about either attack made with the weapons she helped create. No one expected the atomic bombs to be possessed with such great power, and since the time that such power was realized, no atomic bomb has been dropped on such a populated area. In the meantime, Libby missed her studies and returned to the University of Chicago as a research fellow in 1946 after the war was over. In 1948 she became a research associate at the University of Chicago's Institute for Nuclear Studies where she continued to work on nuclear power, trying to perfect and improve it.

Turned to Particle Physics

In 1953 she took on the position of assistant professor of physics at the University of Chicago—a job she held for seven years. While she was teaching, she began researching fundamental particle physics, concentrating on the nucleus. Particle physics, as its name implies, is the branch of physics that deals with subatomic particles or particles that are smaller than the atom, which at one time had been thought to be the smallest material an object could be broken down to. The nucleus, then, is the positively charged dense center of an atom, the part of the cell containing DNA and RNA and which is responsible for growth and reproduction. One of Libby's great discoveries was the detection of cold neutrons. Neutrons are electrically neutral subatomic particles, having a mass much greater than that of the electron. Neutrons, along with the proton, form nearly the entire mass of the nucleus. Cold neutrons are those with a temperature well below room temperature, something that was unusual and had not yet been discovered. Libby built the first rotating neutron spectrometer from her discovery. A spectrometer is an instrument for producing and observing spectra equipped with scales for measuring wavelengths or indexes of refraction. She also at this time investigated nuclear explosions and neutron diffusion.

In 1958 Libby took a position at the Brookhaven National Laboratory in New York. She moved in 1960 to New York University where she became an associate professor, teaching atomic and nuclear physics. In 1964 she moved to Colorado where she took a position at the University of Colorado at Boulder, teaching physics. Libby also won a fellowship at Princeton University's Institute for Advanced Study, where she conducted research with the renowned physicist J. Robert Oppenheimer. From 1963 to 1970 Libby worked at the Rand Corporation in Santa Monica, California, as a physicist.

Studied Cosmology and Ancient Climates

Libby and John Marshall divorced in 1966 and not long after she met and married Willard Frank Libby, a chemist who had won the Nobel Prize in 1960. On a professional front, Libby's interests had changed a bit and she began studying cosmology, which is the study of the physical universe. She was especially excited when she discovered that tree rings could measure ancient climates. In 1970, although still living in Boulder, Libby became a visiting professor at the University of California at Los Angeles's School of Engineering, where she helped develop the department of environmental science and engineering. She left Boulder two years later to move to Los Angeles and become an adjunct professor there.

Libby's second husband died in 1980. Almost immediately she began editing his papers for publication, as they were sought after by many chemists in the field. She was interrupted from her work, however, because around this time there were many demonstrations and ponderings about the safety of nuclear energy. Indignant by the doubters, Libby became a spokesperson for nuclear energy when there were protests against its dangers. She was a staunch endorser of nuclear energy, defending its use until the day she died.

Studied Quasars Until Death

Libby, ever insatiable about finding new and challenging things to research, turned her attention again, at the beginning of the 1980s, and began researching quasars. Unfortunately, she was unable to complete her research before her death. After a long life of exciting, cutting-edge scientific study, Libby died on November 10, 1986, in Santa Monica, California. She left behind a legacy of exploration and innovation, and has been seen as a role model for women who have intended to become scientists in any field of study.

Throughout her life Libby published extensively, writing many books and articles. In particular, Libby was the author of The Uranium People, a book that discussed the details of the events surrounding the Manhattan Project. She also co-edited several works, including The Life Work of Nobel Laureate Willard Frank Libby, which was the result of her editing his papers, which she managed to finish before her death. In addition, she served as an associate editor for the Physical Review from 1960 to 1962. She was a member of the American Physical Society, the Royal Geographical Society, and the National Science Foundation Postdoctoral Fellowship Evaluation Board. In 1992 Libby was posthumously named one of the Women Pioneers in Nuclear Science for her work on the CP-1 nuclear fission reactor.


Notable American Women: A Biographical Dictionary, The Belknap Press of Harvard University, 2004.

Notable Women Scientists, Gale Group, 2000.

Scribner Encyclopedia of American Lives, Volume 2: 1986–1990, Charles Scribner's Sons, 1999.