Tag Archives: history of physics

Cecilia Payne would overcome the adversity that faced women in academia at the turn of the century to blaze a trail through physics and become one of the most important figures in astrophysics.

Who is Cecilia Payne-Gaposchkin: The Woman Who Knew The Stars

It’s almost staggering to think that before 1925 humanity knew very little about the composition of the stars. In fact, we would develop the theories of quantum mechanics, special and general relativity before we knew what lay beneath the surface of the Sun.

The first scientist to develop an accurate theory of the composition of the stars was Cecilia Payne-Gaposchkin. Born Cecilia Helena Payne in a small English market town in Buckinghamshire in 1900, in doing so she would also develop the first accurate picture of the abundance of the elements hydrogen and helium throughout the Universe.

But, these remarkable discoveries were not met with the appreciation one would expect. Payne-Gaposchkin would be discouraged from publishing her findings by a male contemporary. The setback would be just one more obstacle for Cecilia to overcome.

Cecilia Payne-Gaposchkin (1900-1979)

Facing the prejudice and misogyny that typified society in general, and science and academia in particular, during the early 20th Century, Payne-Gaposchkin would show a resolve that led to her becoming the world’s foremost expert on variable stars and enable her to lay the groundwork for astrophysics. 

Through sheer grit and determination, she would redefine our understanding of the composition of the stars and the Universe in general. Not bad for a scientist whose lectures weren’t even listed in her University’s course catalogue, who also had her wages by the same institute paid under ‘equipment costs.’

From Botany to Astronomy

The reward of the young scientist is the emotional thrill of being the first person in the history of the world to see something or to understand something. Nothing can compare with that experience.

Cecilia Payne-Gaposchkin

Things could have been very different for Cecilia Payne-Gaposchkin. Her interest in science first manifested as a fascination with the natural world and botany. A hint towards her future as an astronomer and astrophysicist shone through when Cecilia was just ten and she watched, transfixed, as a meteor traversed the night sky.

Payne’s interest in nature was encouraged by her mother, Emma Leonora Helena Payne, after her father Edward passed away when she was just four years old. The death of her father, who drowned in a canal under questionable circumstances, left young Cecilia devastated and her mother to raise the future astronomer and her two siblings alone.

Emma strongly encouraged the education of her three children, of which Cecilia was the eldest, introducing them to literature at an early age. Cecilia’s traits as a scientist would be further bolstered by her experience at her first school ran by Elizabeth Edwards which strongly encouraged the memorization of facts and figures.

Beyond this, Ms Edwards would actively teach her pupils, including the girls, geometry and algebra. Young Cecilia revelled in the solving of quadratic equations.

“My mother had told me of the Riviera-trapdoor spiders and mimosa and orchids, and I was dazzled by a flash of recognition. For the first time, I knew the leaping of the heart, the sudden enlightenment, that were to become my passion.”

At the age of twelve, Cecilia was forced to move schools when her family relocated from Wendover to London. Her new school, St Mary’s College, Paddington, could not have been less like Ms Edward’s. Like her female contemporaries, at the Church of England school with its strong emphasis on religion and ‘traditional values’ Cecilia would be offered little in the way of educational stimulation and even less encouragement to embark on a career in science.

In fact, it was here that a male teacher would confidently tell Payne-Gaposchkin she would never achieve a career in science. A prediction that may well go down in history as one of the worst ever made by an educator.

The Milky Way’s Trifid Nebula home to many Cepheid variable stars. Cecilia Payne-Gaposchkin would overcome adversity to become one of the foremost experts on such stars (ESO/VVV consortium/D. Minniti)

Fortunately, at the age of 17, Payne-Gaposchkin would be asked to transfer to St. Paul’s Girls School in London. Though the move initially troubled her, it is here where her teachers would allow Cecilia to study elements of physics such as mechanics, dynamics, electricity and magnetism, light, and thermodynamics.

At St. Pauls she was encouraged by her teachers to pursue science, enabling her to obtain a scholarship to Newnham College in 1919 where she would study the slightly odd but eclectic mix of botany, chemistry, and astronomy.

Attending the college, part of Cambridge University, Payne-Gaposchkin soon became bored with botany. Her tutors taught the subject stiffly and rigidly, relaying information she already knew, thus providing Cecilia with little stimulation. She recalled, in particular, an incident in which she discovered a group of desmids whilst studying algae under a microscope. Asking her tutor for help in identifying the organisms, he simply responded that it was not within the remit of her studies so she should just ignore it.

Her decision to switch to astronomy as her major was solidified when she attended a lecture given by Cambridge’s renowned astronomer Sir Arthur Eddington.

Eddington had found fame journeying to the island of Príncipe off the west coast of Africa to examine a solar eclipse that would provide verification for Einstein’s theory of general relativity. The lecture was on the same subject and for Payne, it ignited her desire to study nature beyond the surface of our planet.

Cecilia approached Eddington asking for a research project. He set her the problem of integrating the properties of a model star, starting from initial conditions at the centre and working outward. 

“The problem haunted me day and night. I recall a vivid dream that I was at the center of Betelgeuse, and that, as seen from there, the solution was perfectly plain; but it did not seem so in the light of day.”

Betelgeuse would come to occupy Cecila Payne-Gaposchkin’s thoughts thanks to a problem set by Eddington (ESO/DIGITIZED SKY SURVEY 2/DAVIDE DE MARTIN)

Disappointed at not being able to solve the problem she took her calculations to Eddington incomplete. She need not have worried. Eddington revealed to her with a jovial smile that he had not been able to solve the conumdrum either and had spent years trying!

Building the foundations of Astrophysics

Do not undertake a scientific career in quest of fame or money. There are easier and better ways to reach them. Undertake it only if nothing else will satisfy you; for nothing else is probably what you will receive. Your reward will be the widening of the horizon as you climb. And if you achieve that reward you will ask no other.

Cecilia Payne-Gaposchkin

Eddington was just taken with Payne-Gaposchkin as she was with astronomy, seeing great potential in the young woman. Unfortunately, transferring to the class of Ernest Rutherford, Cecilia discovered that not all of Eddington’s colleagues would be as supportive.

Rutherford, who would go onto perform experiments that would reveal the structure of the atom, was extremely cruel to Payne–the only woman in his class–encouraging the other, exclusively male, students to mock and taunt her, something they did with relish.

Payne-Gaposchkin weathered the storm. She had already experienced what it was like to exist in a male-dominated world and had already overcome too much to fold under mere mockery.

And the indignities would nor end there. Despite completing her coursework, women were forbidden to obtain degrees in the United Kingdom in 1923. Thus Payne-Gaposchkin would have no paperwork to verify her academic achievements. Her chances of obtaining a master’s degree or PhD in the UK were slim to none.

It was upon attending a meeting of the Royal Astronomical Society that Cecilia’s options improved markedly. Its new director Harlow Shipley regaled Payne-Gaposchkin with tales of the opportunities that would await her were she to relocate across the Atlantic to the United States.

Cecilia needed little further encouragement. She was awarded the Pickering Fellowship through Harvard College, taking the small financial aid offered by the only scholarship exclusively for women at the time and using it to move to America. Her association with Havard would continue for many years and prove to be extremely fruitful. Indeed, she would come to consider Boston her second home.

Whilst working under the auspices of Shapely at Harvard College Observatory she continued her studies, finalising what would go on to be her doctoral thesis–Stellar Atmospheres.

Cecilia Payne-Gaposchkin and two astronomers who would have a major influence on her early career. Eddington (centre) would inspire her to embark on the study of astronomy and Ruessell (right) would encourage her not to publish her most important discovery in her doctoral thesis.

In the work, Payne-Gaposchkin would be the first person to suggest that hydrogen was the most abundant element in the universe and the primary constituent of stars. At that time scientists had believed that the Sun and other stars had a chemical composition similar to that of the Earth’s crust. American physicist Henry Norris Russell has pioneered the idea that if earth’s temperature was raised to that of the Sun’s it would have a spectral signature the same as our star.

Payne-Gaposchkin’s finding bucked this idea and arose from the fact she had a much better understanding of atomic spectra than her contemporaries. Unfortunately, American Russell strongly disagreed with her conclusion and persuaded her to leave it out of her thesis.

Payne later reflected on her regret with regards to being persuaded not to publish her findings. It was not a mistake that Payne would never be convinced to make again.

“I was to blame for not having pressed my point. I had given in to Authority when I believed I was right. That is another example of How Not To Do Research. I note it here as a warning to the young. If you are sure of your facts, you should defend your position.”

For what it is worth, Russell too would go on to regret his decision to pressure Cecilia. Russell published a 1929 paper that credited Cecilia as Payne’s earlier work and her discoveries.

It must be one of the most heinous injustices in the history of astronomy that Russell is still to this day often wrongly credited with Payne-Gaposchkin’s discovery.

Russian-American astronomer Otto Struve later recognised the genius of Payne-Gaposchkin’s thesis, describing it as “the most brilliant PhD thesis ever written in astronomy.”

To The Stars and Beyond

The reward of the old scientist is the sense of having seen a vague sketch grow into a masterly landscape.

Cecilia Payne-Gaposchkin

In 1934 on a visit to Germany for an astronomy meeting Cecilia met a young  Russian astronomer, Sergei Gaposchkin. The astronomer was an exile from his country of birth due to his political convictions, and Cecilia found his struggles to be an echo of her own. She was determined to help Sergei find a secure and consistent place to practice science.

Indeed, obtaining Sergei a visa as a stateless person, Cecilia found him a research position at Harvard. To the surprise of their colleagues, the two were married in late 1934. Initial doubts that the marriage wouldn’t last were ill-founded.

Cecilia Payne-Gaposchkin and Sergei Gaposchkin would go on to have three children and remained married until her death in 1979. The two would also form a solid partnership in research, authoring several papers and books together. They even started their own farm–though it’s undeniable that Sergei enjoyed the life of a farmer much more than Cecilia did.

The discovery of the abundances of hydrogen and helium in the Universe and the composition of the stars would not be Payne-Gaposchkin’s only substantial contribution to astronomy and the burgeoning field of astrophysics.

The evolution of the light echo around V838 Monocerotis a variable star. Cecilia Payne was one of the prominant experts on this variety of star. (ESO)

Following the completion of her doctorate, Payne-Gaposchkin would begin to study high luminosity stars in order to understand the composition of the Milky Way. The period marked the beginning of Payne-Gaposchkin’s fascination with variable stars–stars which display periodic brightness fluctuations over radically different periods of time– and novae. This specialization led to the book Stars of High Luminosity, published in 1930.

Cecilia and Sergei undertook an audacious investigation of variable stars, during the ’30s and ’40s, they would make nearly 1.3 million observations of variable stars, with Payne-Gaposchkin’s mind for memorizing facts and figures making her almost a walking compendium of such objects. One of their papers published in 1938 would be the ‘go-to’ tome on variable stars for decades.

During the 1960s, Cecilia and Sergei would shift their attention to the small irregular galaxies situated by the Milky Way–the Magellanic Clouds–and the variable stars located within it. They would make another staggering contribution to astronomy during this study, cataloguing over 2 million visual estimates of these star’s magnitudes.

In 1956, Payne-Gaposchkin would finally be awarded the title of professor, making her the first woman in Harvard’s history to receive such an accolade. She would also be made the chair of a department at Harvard, also the first woman to be recognised in this way. Whilst no one could disagree that the accolade was insultingly well overdue, it was a small positive step in the right direction, finally opening the door for female professors across the US.

The Legacy of Cecilia Payne- Gaposchkin

Payne-Gaposchkin’s most dramatic scientific contribution was the discovery that hydrogen is millions of times more abundant than any other element in the universe. Every high school student knows that Newton discovered gravity, that Darwin discovered evolution, even that Einstein discovered relativity. But when it comes to the composition of our universe, the textbooks simply say that the most prevalent element in the universe is hydrogen. And no one ever wonders how we know…”

Jeremy Knowles, dean of the Harvard University’s Faculty of Arts and Sciences (2002)

Despite waiting so long to be named a professor, Payne-Gadoschkin’s life would not be short on accolades. In 1934, the American Astronomical Society recognized her significant contribution to astronomy by awarding her Annie J. Cannon Prize.

In 1936 she would become a member of the American Philosophical Society, and the 1940s and 1950s marked the award of several honorary doctorates, that should not be viewed as merely consolation prizes for the actual doctorate that she had strived for and had been denied her.

Continuing her trailblazing progress for women in the sciences, in 1976 she would become the first woman to receive the Henry Russell Prize from the American Astronomical Society. The astronomer, who would publish over 150 papers and several books during her career, would receive a further honour in 1977 when the astroid 1974 CA–occupying the asteroid belt between Jupiter and Mars–was renamed 2039 Payne-Gaposchkin.

Amongst the thousands of asteroids between Mars and Jupiter lies 2039 Payne-Gaposchkin a testament to the woman who discovered the composition of the stars.
(Emer O Boyle, Meadhbh O’Connor)

After her semi-retirement in 1966, Payne-Gaposchkin would continue to lecture inspiring the next generation of astronomers. Her final academic paper was published in 1977, just months before her death in December of that year.

During the course of her life, Cecilia Payne- Gaposchkin would change our understanding of the Universe in a way that was no less profound than her colleagues in physics did. Without doubt, her name, therefore, should be listed alongside luminaries such as Copernicus, Newton, and Einstein.

Yet, because of her gender, her genius was barely recognised during her lifetime and her name is still sadly omitted from many textbooks and is nowhere near as prominent as the names of her male counterparts or as her achievements demand.

It is abundantly clear, by becoming the first person to known the true composition of the universe, her star shines just as bright if not brighter as any other scientist. And without her, we still may not know why.

Marie Curie's tale is one of sacrifice and suffering for science and of unparalleled dedication to unlocking nature’s secrets.

Marie Curie: The Price of Knowledge

Marie Curie is rightly regarded as not just one of the greatest women who ever lived, but also, one of the most accomplished scientists in history. Her tale is one of sacrifice and suffering for science and of unparalleled dedication to unlocking nature’s secrets. 

The life and work of Marie Curie will, for better or worse, forever be tied to one substance  — radium. It was Curie, with her husband at her side, that would first isolate this extremely dangerous radioactive element in 1902. The duo synthesized one single gram of radium, which they would use in their work on radioactivity in the following years. The discovery would lead to Curie’s second Nobel Prize, this time in chemistry, in 1911. 

Marie and Pierre at work in their lab (Wellcome Library, London. Wellcome Images/ CCbySa 4.0)

In 1921, whilst touring the states, she would be awarded another solitary gram of the element in recognition of her service to science by the women of America. Poignantly, and cruelly ironically, radium would eventually lead Curie to her death in 1934 as a result of pernicious anemia caused by chronic radiation poisoning. 

But, Curie’s ties to radium would be so monumental that the relationship would continue after her death. Her daughter, Irène, herself a groundbreaking scientist, and her husband Frédéric Joliot, would use the gram of radium Marie had travelled across the Atlantic to obtain as the bedrock that would earn them their own Nobel in 1935. Irène would also follow in her mother’s footsteps in another, far less enviable way, as radiation poisoning would majorly contribute to her death also.

Beyond Curie herself, those two grams of radium have a storied tale surrounding them, if only elements could speak. The first had to be protected against the ravages of the First World War. Whilst the second would not only be saved from the clutches of the Nazis but was so coveted and valuable that before Frédéric married Irène, Marie made her daughter’s suiter sign a prenuptial agreement forfeiting all rights to the radium should they separate. 

The Early Days of Radioactivity

I was taught that the way of progress was neither swift nor easy.”

Marie Curie. 

‘Radioactive’ is a word we take for granted today. It’s well known outside journals and the halls of academia, capturing the attention of the general public from the 1950s onwards thanks to lurid sci-fi tales, and radioactive spider-bites granting teenagers amazing powers.

Yet unlike many other words in common parlance, the first published use of ‘radioactive’ has not been lost to time, it is preserved and still relevant today. That first usage was in the title of Marie and Pierre’s July 1898 paper: ‘On a New Radioactive Substance, Contained in Pitchblende.’

Curie in 1898, the year she and her husband published their paper featuring the first recorded use of the word ‘radioactive’ (Public Domain)

The story of Curie’s exposure to radium and radiation doesn’t begin with her, but with another great scientist, Henri Becquerel. In 1895, whilst intending to study the fluorescent properties of substances such as uranium salts, the French physicist had noticed that uranium blackened photographic plates wrapped in black paper and sealed in a drawer before they had been exposed to sunlight. What Becquerel had discovered was the spontaneous radioactivity of uranium. 

In the same year that Becquerel was making his finding, Marie married her first husband Pierre, who would come to share in many of her accolades. Marie, born Maria Salomee Sklodowska on November 7th, 1867 in Warsaw, Poland, had first met Pierre Curie after moving to France, studying at the Sorbonne and acquiring a position studying magnetism. In order to conduct this research, she would need a lab.

Pierre Curie was a teacher and the head of the laboratory in which Marie found herself, he was also already fairly well-known for his work with magnets. As Marie studied towards a mathematics degree, simultaneously conducting experiments with steel in the lab, Pierre attempted to woo her, at one point attempting to win her affections with an autographed copy of one of his studies. 

After a brief sojourn back to her country of origin, Marie agreed to marry Pierre in July of 1895. She attended the ceremony in a dark blue suit so that she could return to the lab and resume work after the wedding.

Marie, Pierre and daughter Irene, sit on an outdoor bench posing for a picture in 1902. (CORBIS/ Public Domain)

A year later, the couple celebrated the birth of their first child Irène. It was in this same year, 1896, that Marie would become fascinated with the work of Becquerel. Many researchers and scientists had pretty much ignored Becquerel’s uranium finding, but Marie saw further than they did. She decided that his ‘uranium rays’ would make an excellent subject of study for her doctorate. 

The First Gram: Polonium and Radium are isolated

“All my life through, the new sights of nature made me rejoice like a child.”

Marie Curie.

Pitchblende, or ‘bad luck rock’ from the German origin of the name, was the substance that Martin Klaproth, a pharmacist from Berlin, first used to extract and isolate a new element in 1789. This element, uranium, would soon also be joined by polonium — named by Marie for her home country — when the Curies isolated it from pitchblende in 1898.

Pitchblende, a ore that the Curies will become very familiar with. (Jędrzej Pełka/ CCbySA 3.0)

The Curies had examined pitchblende detecting extra radiation that could not be accounted for by considering uranium alone. Marie herself was determined to discover the source of this extra radiation.

The identification of polonium, described in the paper mentioned above, was something of a first in science, marking the first time that an element had been discovered solely as a result of the rays it emitted. It was also the first material to be officially described as radioactive. 

By the point that she discovered that pitchblende contained another element that could be isolated, Curie had checked the periodic table as it existed at the time, finding that thorium also produced rays in a similar way to uranium. 

By December in the same year, Marie was certain she and her husband had isolated another element in pitchblende, one even more radioactive than polonium. She had discovered radium. But if the Curies were to sway the scientific community about the existence of these two new elements, they would have to isolate a pure enough sample of both to establish that both had unique atomic numbers  —  the number of protons in an atom — a count that is unique to every element. 

After obtaining large amounts of pitchblende from a mine in Austria, the Curies set about isolating pure enough radium to identify its atomic number. The process took years and required strenuous physical labour, with Marie having to melt pitchblende and stir it with a metal rod that she described as being larger than she was. During this period, Marie also produced several papers, worked to complete her doctoral degree, taught at a teacher’s college in Sevres, and raised her daughter, Irène.

To give a hint at just how difficult and excruciating the work of isolating the first gram of radium was, consider that the second gram Marie would work with took a team of scientists 500 tonnes of ore, the same amount of acid, over a 1,000 tonnes of coal and 10,000 tonnes of water to extract. Marie and Pierre did themselves. By hand.

Finally, in July of 1902, Marie’s dedication and hard work would pay dividends. She was finally able to determine the atomic weight of radium, identifying it as possessing 88 protons, marking it out from any other elements. 

Words can’t really do justice the sheer physical strain that extracting radium from tonnes of pitchblende put on Marie and Pierre. Nor can it do justice, the damage to their health. (Wellcome Collection gallery/ CCby SA 4.0)

If anyone was in doubt of Marie’s dedication and love for the field of science and the pure pursuit of knowledge, then the action she took upon the identification of radium should be the deciding factor. Had Marie and Pierre claimed the rights to the process of purifying radium, they would have become very rich indeed.

Instead, the Curies rebuffed ideas of personal wealth and shared their process with the wider scientific community. But still, accolades and recognition awaited the pair. 

Unfortunately, so did tragedy and hardship. 

Accolades and Tragedy

“Be less curious about people and more curious about ideas.”

Marie Curie

By 1903 Marie had become the first woman in Europe to receive a doctorate, and she and her husband’s reputations and fame had begun to grow exponentially. But, this increase in notoriety was inversely proportional to their mutual decrease in health.

From the symptoms displayed by the couple at the time, it would now be easy to diagnose severe radiation exposure. Marie, in particular, was suffering from the effects of her work. In addition to the constant state of exhaustion and burnt fingers and hands, shared by Pierre, Marie had suffered a miscarriage and was rapidly losing weight.

Ironically, at the time, radium was being widely touted for its health benefits, it even found its way into cosmetics. It had also already been selected as a cancer treatment showing great potential in curtailing the growth of cancer cells. 

Radium was so touted for its health benefits in the early 20th Century it even found its way into cosmetics. (New York Tribune Magazine, page 12/ Public Domain)

Marie’s ill health prevented her from travelling to Sweden in 1905 to speak on her 1903 Nobel Prize in physics, which she and Pierre shared with Becquerel. 

Yet, despite deteriorating health the three year period between 1903 and 1906 was a happy one, both professionally and personally for the Curies. Pierre would be awarded the Humprey Davy Medal in chemistry in 1903 in addition to his joint Nobel. The substantial monetary award associated with the Nobel prize allowed the Curies to not only continue their research but also, to upgrade their laboratory and equipment.

Thus, the Curies were established as leaders in the field of chemistry, and in radioactivity, of course.

In 1904, the same year as Pierre was made a professor at the Sorbonne and Marie his paid assistant, reflective of the poor treatment of women in science at the time, she gave birth to their second daughter Eve. 

Two years later, tragedy would rear its ugly head in the lives of the Curies, taking with it Pierre. As he crossed the streets of a rain-soaked Paris, a tired and ill Pierre slipped and fell under the wheels of a horse-drawn carriage. The scientist was killed instantly.

A devasted Marie continued her work without her husband, accepting his position at the Sorbonne. She began her first lecture shortly after his death in a crowded lecture hall, stood within steps of where her husband had very recently delivered his last.

 Pure Radium

A scientist in his laboratory is not a mere technician: he is also a child confronting natural phenomena that impress him as though they were fairy tales.

Marie Curie

In 1909, Marie achieved something that Pierre, her late husband, had dreamed of, when plans were drafted to establish the Radium Institute in Paris. Here Marie would oversee her own lab, the Curie Pavillion, a fact that was no doubt bittersweet for the scientist, as her husband had never lived to see it. 

Marie stand resolute in her own lab in 1912, a sight her husband did not live to see. (Public Domain)

The Radium Institute would be completed in 1914, whilst Marie helping considerably in the war effort supplying x-ray equipment for locating shrapnel and bullets in the broken bodies of troops returning from the front. Marie also showed incredible bravery during the First World War, opting to stay in Paris to protect the gram of radium that she and her husband had extracted from tonnes of pitchblende. 

Over this period, Marie continued to synthesise purer and purer radium and polonium, driven on in no small part by the scepticism of some of her fellow scientists, such as Lord Kelvin, who still believed these were not elements in their own right. By 1910 she had produced a bright white metal with a melting point of 700⁰C — pure radium. 

Her professional achievements continued with the publication of work ‘Treatise on Radiation’ published in 1910, and the award of her second Nobel Prize, this time in chemistry awarded in 1911. The same year she was rejected for membership to the French Academy of Sciences. This rebuttal very likely came because of the fact she was a woman, as no one could doubt the pedigree of her work.

Also in 1911, the need for a unit of measurement to describe radiation was determined by an international group of scientists. The Radiology Congress honoured the Curies by naming this unit the ‘Curie,’ but Marie would not simply accept the honour passively. She herself would set about the difficult task of calculating the value of the ‘curie unit (Ci).’

The unit was equivalent to the radiative activity of one gram of radium per second. Unfortunately, as experiments into radioactivity progressed the value of the curie, 3.7 × 10¹⁰ radioactive decays per second., was too large for precise work. It was eventually replaced by the Becquerel (Bq) as the standard unit for radioactivity. 

Marie in a mobile x-ray vehicle used to search soldiers bodies for bullets and shrapnel. (Public Domain)

By the 1920s the dangers of contact with radioactive materials were finally being realised by the scientific community at large. Researchers were using increasingly stringent safety precautions. But it was too late for Marie. 

The damage to Curie’s health had been done. Yet her dedication to her studies, institute and science en masse would take her across the Atlantic on a strenuous speaking tour of the US. For Marie though, the reward wasn’t fame or recognition.

The reward was another gram of radium. 

The Second Gram: Curie’s Sacrifice for Science

“Life is not easy for any of us. But, what of that? We must have perseverance and above all confidence in ourselves.”

Marie Curie.

Marie Curie must have created quite an impression on American journalist Marie Maloney when they met in 1920. By this point, her hands were permanently bandaged. She was near deaf and her vision was afflicted by severe cataracts for which she would need a series of operations to keep at bay.

Curie’s perception in the public’s eye was similarly afflicted. Scandal had surrounded her friendship with physicist Paul Langevin after he left his wife. The newspapers had dogged Marie and the negative attention had had a further detrimental effect on her health. 

1921 visit to the United States: Marie Mattingly Meloney, Irène, Marie and Eve Curie. (Public Domain)

Maloney was determined to restore Curie’s public image, and despite the scientist’s mistrust of journalists in general, the two quickly struck up a friendship. This relationship got off to a notably spikey start. Moloney had already been nervous to interview Curie, and it was only shortly after the process began that the scientist became interrogator questioning the journalist on her knowledge of radium. 

The article Maloney produced for the Delineator hailed Marie Curie as the ‘greatest woman in the world’ and a brilliant scientist. But it was a piece of information that Curie had given Maloney during the interview that reshaped the two women’s lives. 

Maloney was already shocked by the virtually impoverished conditions of Curie’s lab compared to the setups of other scientists the journalist had interviewed such as Edison and Bell, when the scientist informed her about the prohibitive cost of radium. At the time a single gram of the element cost an incredible $100,000 or more. Adjusted for inflation, that’s about $1.3 million dollars today.

Maloney was outraged, and rightfully so. It wasn’t right that this great scientist was denied the resources she desperately needed to conduct her work, whilst her male counterparts seemed well provided for. 

The journalist began a drive across the United States, which had just given women the right to vote, to raise funds to enable Curie to continue her work less constricted by petty financial concerns. 

The Radium Drive, as it would become to be known, was even more of a success than Maloney expected, raising a staggering $156,413 — $2 million today. Not only was Maloney able to acquire the radium for Curie, but she could use the rest of the money to set Marie and her daughters up with a trust fund. 

In return for the generosity, Maloney requested that Curie tour the States and speak to American women. Despite ill-health and being a naturally retiring person, in 1921, Curie agreed. The draw of radium was just too tempting. 

It was only a short time after her arrival in the US with daughters Irène and Ève that the press and public began to notice the strain on Curie. The scientist hated to be seen as vulnerable, to conceal what she saw as a weakness she had kept her many cataract operations secret, but her ill health could not be denied. 

It was at the White House that President Warren Harding presented Marie with the one gram of radium in a 130-pound lead-lined case that opened with a suitably auspicious gold key. Or that was what the press was lead to believe. The radium was actually stored securely at a local government scientific facility.

On July 2nd, Curie returned to Paris. Her arrival home could not have been more in contrast to her arrival in the US via New York. In Paris, there were no brass bands, crowds of well-wishers, girl scout troops to greet her here.

For Marie, there was something much more important here than pomp and circumstance, however. This was where her work was.

After Marie

“Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less.”

Marie Curie.

The gram of radium that Curie collected, which had been extracted for her by scientists at the Standard Chemical Company, near Pittsburgh, would form the bedrock of Curie’s work until 1934 and her death as a result of complications arising from severe radiation exposure. 

Curie in 1925. (American Museum of Natural History/ No Restrictions)

Just the year after her death the same gram of radium would lead Irène and Frédéric to a Nobel Prize in Chemistry in 1935 for their discovery that stable atoms could be encouraged to become radioactive. An important step in nuclear chain reactions.

Irène would follow her mother’s footsteps in another way, displaying remarkable bravery to protect the radium when Nazi troops invaded Paris in 1940. She and her husband, who Marie had forced to sign a prenuptial agreement to waive rights to the element should his marriage to her daughter falter, fled west with the radium to Bordeaux. 

And the trust fund that Maloney had provided for Curie and her girls would be a life-saving asset to Irène and her own daughters in 1944 when Marie’s eldest used it to flee to Switzerland. Sadly, Marie Maloney would never get the satisfaction of knowing that her devotion to Marie Curie had saved her daughter and granddaughter from war-torn Franca, as the firebrand journalist had passed away from pneumonia just the year previous to their daring escape. 

Marie Curie’s life was one of great irony, she risked it many times over for the substance that eventually ended it. But, Curie’s sacrifice, the hardship she worked through, her struggle with grief, physical pain, illness and war, wasn’t really for radium. Nothing so mundane.

It was for knowledge itself and for the betterment of humankind.

I am one of those who think like Nobel, that humanity will draw more good than evil from new discoveries.

Marie Curie.
The tale of physics’ most famous cat is one that is familiar to many, but what is the inside story of the feline so demanding it requires its own Universe, and how does it illustrate the 'weirdness' of the quantum world?

Superposition! The strange tale of Schrödinger’s cat

The tale of physics’ most famous cat is one that is familiar to many, but what is the inside story of the feline so demanding it requires its own Universe, and how does it illustrate the 'weirdness' of the quantum world?
The tale of physics’ most famous cat is one that is familiar to many, but what is the inside story of the feline so demanding it requires its own Universe, and how does it illustrate the ‘weirdness’ of the quantum world? (Robert Lea)

Of all the counter-intuitive elements of quantum physics introduced to the public since its inception in the early days of the twentieth century, it is quite possible that the idea that a system can be two (or more) contradictory things at once, could be the most challenging.

As well as defying a well-known aspect of logic — the law of non-contradiction — thus irritating logisticians, this idea of the coexistence of states, or superposition, was even a challenge to the fathers of quantum physics. Chief amongst them Erwin Schrödinger, who suggested a diabolical thought experiment that would show what he believed to the ludicrous nature of a system existing in contradictory states. 

The thought experiment would go on to become perhaps the most well-known in the history of physics, weaving its way on to witty t-shirts, hats, bags and badges, infiltrating pop-culture, TV and film. This is the strange tale of Schrödinger’s cat, and what it can teach us about quantum physics and the nature of reality itself. 

Before delving into the experiment that Schrödinger devised, it is worth examining the circumstances that led him to consider the absurd situation of a cat that is both living and dead at the same time. 

Wanted: Dead or Alive! How the cat got put in the box

In many ways, Erwin Schrödinger’s place in the history of quantum mechanics is overshadowed by his feline-based thought experiment. The Austrian physicist was responsible for laying the foundation of a theoretical understanding of quantum physics with the introduction of his eponymous wave equation in 1926. As Joy Manners describes in the book ‘Quantum Physics: An Introduction’:

“The Schrödinger equation did for quantum mechanics what Newton’s laws of motion had done for classical mechanics 250 years before.”

Joy Manners, Quantum Physics: An Introduction

What Schrödinger’s equation shows is that the state of a system — the collection of all of its measurable qualities — can be described as a wavefunction — represented by the Greek letter Psi (Ψ). This wavefunction contains all the information of a system that it is possible to hold. Each wavefunction is a solution to Schrödinger’s equation, but here’s the crazy part; two wavefunctions can be combined to form a third, and this resultant wavefunction can contain completely contradictory information.

When the wavefunctions of a system are combined it is in a ‘superposition’ state. There is also no limit no how many of these wavefunctions cam be combined to form a superposition. 

Yet, infinite though a wavefunction can be, eternal it is not. The act of taking a measurement on the system in question seems to cause the wavefunction to collapse — something there is as yet no physical or mathematical description for. There are, however, interpretations of what happens, which go to the very heart of reality.

Before tackling these interpretations, first, we should get to our cat in the box before he gets too impatient. 

A most diabolical device 

It was in 1935, whilst living in Oxford fleeing the rise of the Nazis, that Schrödinger first published an article that expressed his concern with the idea of measurement, wave function collapse, and contradictory states in quantum mechanics. Little would he know, it would lead to him becoming history’s most infamous theoretical-cat-assassin. 

A common illustration of the Schrodinger’s Cat thought experiment (Dhatfield / CCbySA 3.0)

Below Schrödinger describes the terrible predicament that his unfortunate moggy finds himself in. 

“A cat is placed in a steel chamber with the following hellish contraption… In a Gieger counter a tiny amount of a radioactive substance, so that maybe within an hour one of the atoms decays, but equally probable is that no atom decays…”

So, there is a 1/2 chance that an atom of the substances decays and causes the Gieger to tick over the hour duration of the experiment. 

“If one decays the counter triggers a little hammer which breaks a container of cyanide.” 

So, if the atom decays over the hour, the cat is killed. If it doesn’t, the cat survives. Treating the box and the cat as a quantum system how would we describe its wavefunction (Ψ)?

The wavefunction of the system now exists in a superposition of the individual wavefunction that describes the cat as being alive, and the one that declares it dead. According to the rules of quantum physics, the cat is currently both dead and alive.

Our unfortunate feline isn’t doomed to live out its existence as some bizarre quantum zombie, though. A quick peek inside the box constitutes a measurement of the system. Thus, by opening the box we collapse the wavefunction and determine the fate of Schrödinger’s cat. It really is curiosity that kills the cat, in this case.

Let’s end our analogy on a happy note. We open our box and fortunately the substance has not undergone decay. The cyanide bottle remains intact. Our moggy survives, unscathed if irritated. The wavefunction collapsed leaving the blue sub-wavefunction intact, but what actually just happened here? How was the cat’s fate determined? 

The short answer is, we don’t know, but we have some interpretations. Next, we compare the two most prominent. 

Way more than nine lives. The many-worlds interpretation 

What we have discussed thus far consists of a very rough description of the Copenhagen interpretation of quantum mechanics. The reason it’s common sense to present this first is that it is generally the interpretation that is most widely accepted and taught.

As you’ve seen, the Copenhagen interpretation describes a system with no established values until a measurement occurs or is taken and a value — in our case ‘alive’ — emerges. If this sounds deeply unsatisfactory, well, it is. One of the questions it leaves open is ‘why does the wavefunction collapse?’

In 1957, an American physicist Hugh Everett III, asked a different question: ‘What if the wavefunction doesn’t collapse at all? What if it grows?’ From this emerged Everett’s ‘relative state formulation’, better known to fans of science fiction, comic books and fantasy as the ‘Many Worlds Hypothesis/interpretation’.

Below we see what happens to the wavefunction in the Copenhagen interpretation. The box is opened and the wavefunction collapses. 

So what happens in the ‘many worlds’ interpretation? Rather than collapsing, as the box is opened the wavefunction expands. The cat does not cease to be in a superposition, but that superposition now includes the researchers and the very universe they inhabit. We become part of the system.

In the many-worlds interpretation, the researchers do not open the box to discover if the cat is dead or alive, they open the box to see if they are in the universe where the cat survived or the universe in which it was dispatched. They and their world have become part of the wavefunction. An entirely new universe in superposition with the old. The only difference. 

One less cat.

Schrodinger’s Kittens: Some words of caution

Again, as with the Copenhagen interpretation, there is no real experimental evidence of many worlds concept. In many ways, any interpretation of quantum mechanics is really more a realm of philosophy than science. Also, when considering ‘many worlds’ it’s worth noting that this is a different concept than the idea of a ‘multiverse’ of different universes created at the beginning of time. 

Further to this, there are some real problems with considering the ‘cat in a box’ as a quantum system. Researchers are constantly finding quantum effects in larger and larger systems, the current record seems to be 2,000 atoms placed in a superposition. To put that into perspective; a humble cat treat contains around 10²² atoms!

Many physicists have suggested reasons why larger systems fail to display quantum effects, with Roger Penrose suggesting that any system that has enough mass to affect space-time via Einstein’s theory of general relativity can’t be isolated. Via the influence of gravity, it is constantly having ‘measurements’ taken. This would definitely apply to even the most minuscule moggy. 

It is worth noting here that the general description of the thought experiment and the opening of the box has led some to speculate that it is the addition of a ‘consciousness’ that actually causes the wavefunction collapse. 

This is an idea that has sold a million or so books on ‘quantum woo’ and it arises from the unfortunate nomenclature of quantum physics. The use of the words ‘measure’ and ‘observe’ imply the intervention of a conscious observer. The truth is that any interaction with another system is enough to collapse a quantum wavefunction, as they tend to exist in incredibly delicate, easily disturbed states. 

Sources and further reading

Schrödinger. E,

Griffiths. D. J, ‘Introduction to Quantum Mechanics,’ [2017], Cambridge University Press.

Broadhurst. D, Capper. D, Dubin. D, et al, ‘Quantum Physics: An Introduction,’ [2008], Open University Press.

Nomura. Y, Poirer. B, Terning. J, ‘Quantum Physics, Mini Black Holes, and the Multiverse,’

Orzel. C, ‘How to Teach Quantum Physics to your Dog,’ [2009], Simon & Schuster.