The biography of Marie Curie continues with marriage to Pierre Curie, Marie's discoveries about radioactivity, and celebrity.


Pursued by Pierre Curie

In 1893, Marie completed her Masters degree in Physics on schedule, graduating first in her class as usual. Student life in Paris must have appealed to her because she continued her studies, enrolling next in a Masters program in mathematics. She finished this in one year, graduating second in her class. These were wonderful achievements for a student who was forced to study on her own for six years attending a secret "university" on and off. But her educational triumphs were dimmed somewhat by an even more important event that occured a few months before graduation. One spring day, at a friend's apartment, Marie was introduced to a dreamy somewhat detached, 35 year-old physicist who had made a name for himself, in scientific circles, as the discoverer of piezo-electricity. This would be a turning point in both their lives. Pierre Curie was his name, and in a few months, he would propose that they spend the rest of the scientific lives together.

The Curie French 500 Franc


Both of these young physicists had been disappointed in love, and they were both dedicating their bachelor lives to physics in all its complexity and beauty. Yet, they were different in some obvious ways. Marie was a "go-getter", a woman with tremendous drive and ambition. She was a product of the school system, racking up many firsts by the time she met Pierre. Pierre, on the other hand, was a school system drop-out. His parents had him home-schooled with some capable tutors in the more advanced courses. Like Albert Einstein and Neils Bohr, Pierre may have had a learning disability. Nevertheless, he passed his entrance exam for the Sorbonne and obtained his masters degree, the licence es sciences, at the age of 18. Working with his brother, he began investigating crystals. This research led to the discovery of piezo-electricity three years later. He published a number of important papers, but his unorthodox schooling and his failure to write up his thesis and finish his doctorate virtually barred him from positions at all the top schools in France. Pierre was the "ultimate outsider" as one biographer has described him.

"It would be fine thing ... to pass our lives near to each other,
hypnotized by our dreams; your patriotic dream,
our humanitarian dream, and our scientific dream."
Pierre to Marie, in a letter, 1894


When Pierre met Marie, he was working as an instructor at the EPCI, a technical college in Paris. His career had been stagnating for several years, but all that was about to change. Once he decided to win over Marie and persuade her to marry him, he took steps to make himself a viable husband and provider. He wrote up his PhD thesis, for example, and he was awarded his doctorate, albeit somewhat late in his career. He hated any type of self-promotion, believing that if one were talented, they would rise to the top. The more practical Marie may have pushed him to get his doctorate. He also signed several royalty contracts on instruments he designed. The royalty fees would add to his modest salary from the EPCI.

Marie still had serious reservations about marrying Pierre. For one thing, she didn't want to give up her independence as a single woman. Married to Pierre, she would have to do the usual cooking and cleaning, leaving less time for physics. Pierre countered with the suggestion that they "live together" in adjacent apartments. Another major obstacle was the fact that Pierre was not Polish. If she married him, she would have to give up her patriotic dream of returning home to liberate Poland. Pierre then offered to emigrate to Poland and live with her there. As the months passed, Marie realized that she and Pierre were compatible, and that they shared a postivist political and scientific vision. Slowly, she fell in love with this eccentric idealist. They were married in a simple ceremony on July 26, 1895.

Collaboration on Radioactivity

The next 14 years spent collaborating with Pierre on radioactive elements would be the most thrilling time of Marie Curie's life. Marie assumed the role of chemist, extracting and purifying radioactive elements while Pierre focused on the physics of radioactive substances. Marie picked her own topic for research: to find more radioactive elements like the Uranium discovered by Becquerel one year earlier. Pierre arranged for her to work in a room provided by the EPCI on rue Lhomond. It was a drafty, dirty "potato shed" compared to the laboratories over at the Sorbonne. Radioactive substances were probably not the best choice for a PhD thesis either, but it was a very new phenomenon and that sort of thing would have appealed to Pierre. His influence on her research is evident in other ways. For example, Marie surveyed a large number of mineral ores similar to the way Pierre surveyed crystals earlier in his career. Marie also relied on piezo-electrical instruments invented by Pierre to measure the radiative particles emanating from her purifed samples.

"Errors are notoriously hard to kill, but an error
which ascribes to a man what was actually the work
of a woman has more lives than a cat."
- Hertha Ayrton


While it may be true that Pierre acted like her thesis advisor, Marie Curie published several papers under her own name, during this time, in which she set out her own theories and conclusions about the new radioactive elements she believed existed in uranium ore. Critics have charged that Pierre came up with all the ideas, and that in the years after he died, she did not publish anything important. The fact is that physics is a young persons game, so to speak, and most physicists come up with their best ideas while they are graduate students or post-docs. If they keep meticulous lab notebooks and records, they might actually get credit for their theories. Luckily for Marie, she kept very detailed notes in her lab books which now reside in the Bibliotheque Nationale in Paris. It is clear from these notebooks that Marie contributed some of the most important ideas during the Curies' years of collaboration. The most important one was her conclusion that radioactivity is an "atomic" phenomenon, not something caused by the molecular structure of the mineral compounds. Around 1900, not all scientists were convinced that atoms existed; the physical evidence like Einstein's explanation of brownian motion was still very skimpy. It was daring to propose that there are processes going on inside atoms causing radioactivity.

"Marie Curie . . . the one person whom fame has not corrupted."
- Albert Einstein


Yet, Marie Curie was exactly right. The importance of her "atomic" radioactivity cannot be over-estimated. In many ways, it launched the atomic age and what we think of today as modern physics. For the next 100 years, physicists would focus their investigations on processes and particles inside the atom. Unraveling the mysteries of the atom would ultimately lead to the theory of Quantum Mechanics, one of the greatest scientific achievements of the twentieth century. In 1903, both Marie and Pierre Curie and Henri Becquerel were awarded the Nobel Prize in Physics for their work on radioactivity.

The Dangerous Beauty of Radium

The actual process of extracting the radioactive element radium from uranium ore was a physically grueling task. It took Marie several years to produce one tenth of a liter of pure radium from tons of rock mined out of the earth. She established that one mole of radium had a mass of 226 grams. On most days, she worked over a large vat outside her laboratory shed. On rainy days, she had to move inside though the lab room was cold and drafty. The latter turned out to be a blessing in disguise since noxious radon gas was being produced, and everything in the lab was contaminated. One science historian has estimated that Marie was exposed to about 1 rem ( a unit of radiation) per week. By today's standard, a much smaller amount of .03 rem is considered dangerous.

"Just at present, the world has run raving mad on the subject of radium,
which has excited our credulity precisely as the apparitions at Lourdes
excited the credulity of Roman Catholics."

- G.B. Shaw, introduction to his play The Doctor's Dilemma
After the Curies won their first Nobel Prize, the popular press around the world declared radium a miracle drug. Marie kept a glass vial of radium salts on the stand next to her bed at home. She was enchanted with the soft, blue glow it produced in the dark. Both Marie and Pierre were swept along by all the publicity, and they played down the negative health effects they experienced. For example, their finger tips were permanently scarred, hardened, and in constant pain from handling radioactive samples. Pierre, Marie, and Becquerel had all suffered accidental burns on their skin when they carried samples of radium salts in their clothing for a few hours. Marie was always tired "without being exactly ill," and she lost more than 15 pounds. Today, it is well-established that fatigue and depression are side-effects of radiation over-exposure. The worst tragedy occurred when, after giving birth successfully to Irene (her first child), she suffered a miscarriage in her fifth month in1903 probably due to radiation exposure. She had not felt well during either pregnancy. Marie was very disappointed, and this dampened whatever satisfaction she got from obtaining her doctorate earlier in the year.

Bookmark: The Radium Girls


What the Curies and the world did not know, although the evidence was mounting, is that radium and other radioactive substances give off a powerful, invisible light energy called gamma rays. These gamma rays are very destructive to animal and human body tissues because they can penetrate anything except lead. In December of 1903, neither Pierre or Marie felt well enough to travel to Stockholm to receive their Nobel medals in person. Their physician, however, could find nothing wrong with them. Marie's lungs were checked for TB, and they were clear. Perhaps the Curies had more down-to-earth problems on their minds. One of the few things they bought with their Nobel prize money was a modern bathroom with a toilet for their home. In 1900, two out of three French residences did not have indoor plumbing.

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The Radium Institute / Pierre's Death / The Langevin Affair

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