The 3 women who changed the way we see the universe

Henrietta Swan Leavitt, Cecilia Payne-Gaposchkin and Vera Rubin have managed to overcome prejudices and obstacles, contributing to a better understanding of today’s cosmos.

They had to face the prejudices of society, colleagues and teachers. They received the lowest wages, their work was often ignored because they were women, or their peers or superiors simply appropriated their discoveries.

They’ve even had to fight for basic things, like a ladies’ restroom in the workplace.

Very few have received their deserved recognition in life. But there are many female pioneers in astronomy. Her work has helped us understand a little more about the Universe.

We highlight three examples of these women who have overcome obstacles – some of which many women still face today – to change the way we understand the cosmos and inspire future generations: Henrietta Swan Leavitt, Cecilia Payne-Gaposchkin and Vera Rubin .

Cecilia Payne-Gaposchkin, Vera Rubin and Henrietta Swan Leavitt

Image: Getty Images, AIP and Schlesinger Library.

Henrietta Swan Leavitt: The Measures of the Universe

One of the pioneers of astronomy, the American Henrietta Swan Leavitt (1868-1921) began working at the Harvard College Observatory in 1895.

She charged 30 cents an hour and had been nearly deaf since she was 17. But her discoveries gave us the key to understanding the measurements of the universe and are still used today to measure the expansion of the cosmos.

Leavitt was one of an extraordinary group of women known as the “Harvard computers.” Astronomer Edward Charles Pickering commissioned them to process and classify the huge amount of images of the universe needed for his studies.

Women paid much less. Thus, Pickering was able to hire several employees. They were also considered conscientious and observant, ideal for the monotonous and repetitive work required of data analysis.

As they were women, none of them had the right to operate the telescopes, which greatly limited their work. And colleagues disparagingly referred to the group as “Pickering’s harem.”

Leavitt was commissioned to work with variable stars called Cepheids, whose brightness changes over time.

In 1908, despite the restrictions imposed on his work, he noticed a detail to which other scientists had not paid much attention: the stars twinkled with a regular rhythm and the longer the period, the greater their intrinsic brightness.

This model is known today as “Leavitt’s law”. According to her, a star that takes longer to shine is inherently brighter than one that blinks rapidly.

The discovery might have been mere curiosity, until Leavitt applied this knowledge to images of the Small Magellanic Cloud, a dwarf galaxy close to the Milky Way. And in this smaller sample, his theory could be seen even more clearly.

Leavitt concluded that by simply measuring the rate of the pulsation (which can vary from days to weeks) and observing its brightness from Earth, the astronomer can infer the distance to the observed object. The discovery was so revolutionary that it transformed the two-dimensional image we had of the Universe into a 3D image.

His work, perhaps because it was advanced for its time or simply because it was the work of a woman, was abandoned for a decade and resumed only after the premature death of its discoverer, a victim of stomach cancer.

Astronomer Edwin Hubble built on Leavitt’s 1920 discovery to deduce that the patches of light in the sky are entire galaxies, far more distant than our own. Thus, he taught us that the universe is much bigger than we imagined.

Cecilia Payne-Gaposchkin: the matter that makes the stars

Cecilia Payne (later Payne-Gaposchkin, 1900-1979) was the only woman in her physics class at Cambridge University, UK. She had to sit in the front row and endure the daily humiliation of her colleagues.

One of his teachers was the father of nuclear physics, Ernest Rutherford. He stared at her and began the lesson: “Ladies and gentlemen…”

“All the men regularly greeted this scene with thunderous applause and stomping…every class, I wanted to sink into the earth. To this day, I instinctively take the deepest possible seat in a classroom,” Payne-Gaposchkin confessed in his autobiography .

The contempt of her colleagues did not discourage her. But she Payne thought that, as a woman, she would have more opportunities to work in astronomy in the US than in her native UK than she did.

In fact, despite completing her studies at Cambridge, she never managed to graduate. The University would only allow women to graduate in 1948.

In 1923, Payne-Gaposchkin was awarded a scholarship to enter the Harvard College Observatory in the United States. There, she worked alongside female “Harvard computers,” as well as Henrietta Swan Leavitt.

Using the latest knowledge of quantum physics, he came up with the idea that stars are composed mainly of hydrogen and helium. It was a revolutionary idea at the time.

Payne-Gaposchkin arrived at this conclusion after carefully relating different types of stellar spectra to their effective temperatures by applying the theory of ionization developed by the Indian astrophysicist Meghnad Saha.

He observed a large variation in stellar absorption lines and showed that this variation was due to different ionization levels at different temperatures, not different amounts of elements.

Until then, science hadn’t been able to deduce what stars were made of. It was believed that its ingredients would be similar to those of planet Earth. But Payne-Gaposchkin claimed that stars were much simpler than previously thought and included his findings in his doctoral thesis.

In 1925, one of the most recognized astronomers of the time, Henry Norris Russell, advised Payne-Gaposchkin to drop this idea from the thesis, because it went against the mainstream of thought. But a few years later Russell came to the same conclusion as Payne using other methods. Thus he ended up, for many years, receiving the credit for the discovery.

A pioneer in many fields, Payne-Gaposchkin was the first doctor and physicist at Radcliffe College, as the women’s section of Harvard was then called. And years later, she became the first woman to head the Astronomy Department at Harvard University.

Vera Rubin: the pioneer of dark matter

As a young girl, Vera Rubin (1928-2016) built her first telescope out of a cardboard tube won at a linoleum store and small lenses purchased at a science supply store.

Years later, she was the first woman authorized to manage the Palomar Observatory in California (USA). There she made a discovery whose mysteries are still being deciphered today: dark matter.

Currently, the observatory with the most powerful lens ever made for a telescope is under construction in northern Chile and bears his name.

His family has always encouraged his talent and passion for science. But when Rubin told her physics professor at the institute, where she was virtually the only woman, that she intended to go to college, she advised her to avoid scientific careers.

Fortunately, Rubin paid no attention and graduated from Vassar College in the United States in 1948.

She completed her doctorate six years later while caring for her young children. She often had to attend evening classes while her parents looked after the children and her husband, also a scientist, waited in the car.

Vera Rubin has had to face, for most of her career, the sexist prejudices of those who considered life as a mother of four children incompatible with science, but she was always combative.

One example occurred when she finally gained access to the Palomar Observatory, where there were no women’s restrooms. Rubin decided to reaffirm his position and taped a sheet of paper to the door of the men’s room to create his position.

All her life she fought for the inclusion of women in scientific committees and conferences.

Rubin was fascinated by spiral galaxies and wanted to study how they rotated. At the time, it was thought that the rotation should slow down with distance from the center of the galaxy, in the same way that planets orbit more slowly the farther they are from the Sun.

In one of his early studies, he questioned this idea, and while his position was met with skepticism, it turned out he was right.

Later, in the 1970s, Rubin discovered something startling. The galaxies he observed were rotating so fast that it would make sense for them to separate if the only thing responsible for holding them together was the stars’ gravity.

But since the galaxies didn’t separate, there must have been something larger, but totally invisible, exerting that force: dark matter.

Today, 50 years later, we know that dark matter makes up about 84% of the Universe. We’re still trying to figure out what it is.

– This text was published at

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