Discovered polonium and radium, which prompted the revolutionary conclusion that atoms are not indivisible; this, in turn, led to the creation of nuclear and high-energy physics, opening UP disruptive innovations in chemistry, medicine, power generation, and weaponry
MARIE CURIE
(1867–1934)
Born November 7, 1867 into a Warsaw family, highly educated but impoverished by government confiscation of property during their involvement in uprisings aimed at Polish independence, Maria Skłodowska struggled to attain her own education. She attended local public schools while also studying at home with her father, a secondary-school teacher whose political activism had cost him his job. Maria’s oldest sibling, Zofia, had succumbed in 1874 to typhus, which she contracted from one of the boarders her mother and father took in to help make ends meet. Three years later, Maria’s mother, Bronisława, died of tuberculosis, and ten-year-old Maria grew closer to her teacher-father, who gave her a thorough grounding in the sciences—and who inspired her involvement in a Warsaw students’ revolutionary group.
With Polish universities open only to male students, Maria and her sister Bronisława (named for their mother) became active in an underground “Flying University” (Uniwersytet Latajacy), which was not only covert, but a hotbed of nationalist revolutionary activity. Feeling the authorities breathing down her neck, Maria fled Russian-dominated Warsaw for Cracow, which was then part of the Austro-Hungarian Empire. After further struggle in that city, she went to Paris, to which Bronisława had moved earlier with her physician husband. Maria enrolled at the Sorbonne, from which she obtained licentiateships (the equivalent of master’s degrees) in physics and mathematics.
While studying at the university in 1894, she met Pierre Curie, professor in the school of physics. The two married in 1895. That same year, the German physicist Wilhelm Röntgen discovered X-rays. The following year, the French scientist Henri Becquerel discovered that uranium salts emitted rays he concluded were similar to X-rays because, like them, they had the power to penetrate solid matter. When Becquerel demonstrated that the energy radiated from the uranium salts was a property of the salts and not derived from any external source, Marie Curie, in search of a subject for a doctoral thesis, decided to study these “uranium rays.” She made use of a modified electrometer Pierre Curie had developed years earlier. With it, she demonstrated that the uranium rays caused the air around a sample to conduct electricity. Using the electrometer, she was able to measure the degree of activity of uranium salts and showed that the amount of activity depended on nothing other than the quantity of uranium present. This led her to propose that the activity—the radiation—came not from molecules in the impure uranium compound but from the atoms of the underlying element. In other words, contrary to untold centuries of atomic theory, atoms were divisible into smaller particles, which, in this case, were highly energetic.
The birth of the Curies’ daughter Irène in 1897 prompted Marie to accept a teaching post at the École Normale Supérieure to help support the child. Nevertheless, she and Pierre made time to research two uranium minerals, pitchblende and torbernite, in an effort to refine them to their constituent elements. The only space available to them was a wretched shed, which had served as a medical school dissecting room. They labored here, quite unaware that their continuous close work with radioactive substances was harmful and, ultimately, lethal. Finding that both pitchblende and torbernite were more radioactive than uranium alone, Marie Curie concluded that the minerals must contain another substance far more radioactive than uranium. By 1898, Pierre Curie abandoned his own research to collaborate with his wife on hers. In April and July of that year, the Curies announced the existence of two previously undiscovered elements, polonium (which Marie named in honor of her native country) and radium (Latin for ray).
They were now faced with the task of isolating the actual elements. The elements existed in such small quantities in pitchblende that it required years of work to isolate them. From one ton of pitchblende ore, a mere tenth of a gram of radium chloride was finally separated in 1902. It took another eight years to isolate a trace amount of the pure radium metal. By that time, Marie was working alone, her husband having been killed on April 19, 1906, when he slipped on a rainy Paris street and was run over by a horse-drawn wagon. (Madame Curie never succeeded in isolating polonium, an element with a fugitive 138-day half-life, compared to radium’s 1600-year half-life.)
Pure radium is an element. An element is an atom, not a molecule. The fact that radium, an atom, emitted radiation meant that energized particles were being thrown off by the radium atoms. This, in turn, meant that the atom—assumed since ancient times to be the final, indivisible building block of matter—was capable of being divided into smaller particles. By itself, this discovery was tremendously disruptive, forever changing a basic assumption about the nature of the physical world.
But there was more. Curie had discovered an elemental source of energy. Among the thirty-two papers she and her husband had published (separately or jointly) between 1898 and 1902, one revealed the extraordinary result of exposing tumor cells to radium: the diseased cells died before the healthy ones. Radiation, it seemed, might be a cure for cancer. Who knew what other miracles the new energy source would be capable of creating?
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During the long period of her work with radium, Marie Curie rose rapidly in French intellectual and academic circles. In 1900, she was appointed the first woman on the faculty of the École Normale Supérieure. In 1903, she was awarded a doctorate from the University of Paris. Also in 1903, Marie and Pierre Curie shared with Henri Becquerel the Nobel Prize in Physics for their research into the “radiation phenomena” that Becquerel was credited with having discovered. Marie Curie was the first woman to be awarded a Nobel Prize.
Following Pierre’s death in 1906, Marie Curie was given his place as professor of general physics on the faculty of sciences at the University of Paris, the first woman to hold that position. In 1911, she was awarded a second Nobel Prize, this time not in physics but in chemistry, for her discovery of polonium and radium and her isolation of radium. This made her not only the first woman to receive two Nobel Prizes (at the time of this writing, she is still the only woman to have done this), but the first person, man or woman, to be awarded prizes in two different scientific fields.
In 1914, Madame Curie was appointed director of the Curie Laboratory in the brand-new Radium Institute of the University of Paris. In addition, she received many honorary science, medicine, and law degrees, as well as honorary memberships in learned societies worldwide. With Pierre Curie, she received the Davy Medal of the Royal Society in 1903, and, in 1921, U.S. President Warren G. Harding, “on behalf of the women of America,” presented her with a highly valuable gram of radium in recognition of her service to science.
The honors were great and many. Having disrupted physics and chemistry, having disrupted an ancient and, it had seemed, eternal principle of physical reality—the indivisibility of the atom—and having blurred the absolute distinction between matter and energy by her work with atomic radiation, Marie Curie also upended equally entrenched concepts of gender roles by achieving in rapid succession so many lofty firsts for women. Her daughter Irène would go on in 1935 to share a Nobel Prize for Chemistry with her husband, Frédéric Joliot.
Yet there was also a terrible price to pay for all this. On July 4, 1934, while visiting her native Poland, a now sickly Marie Curie died from the effects of aplastic anemia. Almost certainly, her illness was related to her frequent and long-term exposure to radiation—not only in the laboratory, but during her voluntary service as a radiologist operating a mobile X-ray truck with primitive and totally unshielded equipment in French field hospitals during World War I. Indeed, both she and her husband had suffered from various chronic and increasingly debilitating ailments—in her case, including cataracts that nearly blinded her. All were almost certainly caused by radiation exposure.
Even Curie’s legacy is radioactive. To this day, her personal papers are stored in lead-lined boxes and can be handled only by scholars who are willing to don protective clothing and limit their exposure. Irène Joliot-Curie, the daughter who, as a young woman, often assisted her mother in the laboratory, died of leukemia in 1956 at the age of fifty-eight. Her name is commemorated with that of her mother and 357 other researchers on the Monument to the X-ray and Radium Martyrs of All Nations, in Hamburg, Germany.