Here is a brief excerpt from an article by Veronique Greenwood about Elizabeth Rona, one of a countless number of persons who were overlooked is a series of obituaries about remarkable people whose deaths, beginning in 1851, went unreported in The Times.

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Rona moved from lab to lab — and country to country — and in the process made important findings about the behavior of atoms and radioactivity.

The phone call for Elizabeth Rona came to the Budapest university where she worked: Don’t go to the theater, the caller warned.

Rona, who was celebrating her 29th birthday, had planned to meet her family there in a few hours, but she learned that militants had taken control of the building. It was one of many incidents in the upheaval that was tearing at Hungary in the immediate aftermath of World War I and the disintegration of the Austro-Hungarian Empire.

It was also typical of the unsettled world that Rona — a woman who was ethnically Jewish in a male-dominated world plagued by anti-Semitism — had to navigate throughout her career as a chemist researching the strange new science of radioactivity.

Rona moved from lab to lab — often from country to country — to seize opportunities for research. As a result of her work, the world would learn fundamental details of the behavior of atoms and how radioactivity could be used as a clock in studying the earth’s history, informing the modern practice of geochronology.

The earth is threaded with radioactive isotopes that decay at a constant rate into other substances, a process that scientists can use to study the planet’s history. For example, the more recent past can be examined by measuring how much carbon-14 in a sample has decayed into nitrogen, with each stage of decay like the ticking of a second hand. For the more distant past, scientists can examine how much potassium-40 has turned into argon-40, or choose another pair that fits their needs. Radiometric dating lets scientists assign dates to objects, like fossils and ancient coral reefs, which reflect the planet’s past climate.

Elizabeth Rona was born on March 20, 1890, in Budapest to Ida Mahler and Samuel Rona. Her father was a doctor, and she wanted to become a doctor, too. But her father, fearing the work would be difficult for a woman, encouraged her to study chemistry instead. After earning her Ph.D. at the University of Budapest, she worked as a researcher with the radiochemist Kasimir Fajans at the University of Karlsruhe (now the Karlsruhe Institute of Technology) in Germany.

She returned to Hungary and worked with George von Hevesy, a chemist whose experiments used radioactive versions of elements as tracers to explore chemical reactions. Rona and von Hevesy tracked the diffusion of radioactive tracers in various materials to see how quickly atoms of a substance drifted from one area to another. With that information, it would be possible to calculate an atom’s size, which could then be used to help explain its behavior.

In those early days, radiochemistry was a kind of scavenger hunt to collect and understand these features. Every kernel of information was swiftly fed into new theories and predictions about radioactivity and atoms.

Von Hevesy and Rona’s findings were important for other scientists, but the tracers, for which von Hevesy eventually won the Nobel Prize, turned out to have even broader uses: For decades now, doctors have injected radioactive tracers into patients to aid in diagnosing conditions like cancer and heart disease.

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Here is a direct link to the complete article.