7 women scientists who changed the world

National Geographic pays tribute to seven women scientists who, through their discoveries, have changed the world.
Juliette Heuzebroc, Romy Roynard

“Women scientists” sounded like a sweet oxymoron to the ears of a largely male-dominated research community. Many of them were shunned by the awards or had their discoveries stolen because they were women.
For centuries, female researchers had to “volunteer” to assist members of science faculties, and their major discoveries were attributed to their male colleagues and their names were removed from experimental protocols.
They often had to fight for even the “natural recognition given to their husbands or colleagues,” says Anne Lincoln, a sociologist at Texas Methodist University who has studied the barriers to women in the history of science.
According to a study conducted in 2014, women are still under-represented in science: only a third of researchers are women. Yet many women scientists have participated in discoveries that have changed our world.
On International Women’s Rights Day, National Geographic is honoring seven women scientists who have made major discoveries without always receiving the credit they deserve, simply because they were born women.


© marie crayon / national geographic

Born in 1868 in Massachusetts, Henrietta Swan Leavitt is an American astronomer. In 1893, she was recruited at the Harvard University Observatory to join “Harvard Computers”, a group of women hired to establish mathematical processing of astronomical data; women were not allowed to use telescopes at the time. Henrietta Leavitt was responsible for examining photographic plates taken at different periods in order to measure and classify the brightness of stars.
In 1908 and 1912, she published the results of her work on the Magellanic Clouds, a group of dwarf galaxies. Her observations enabled her to detect the periodic variation in the luminosity of certain stars, the cepheids. She thus established the period-luminosity ratio, known as Leavitt’s Law, which has enabled astronomers to develop a system for calculating distances in the universe and thus measure the distance between our planet and other galaxies.
Henrietta Leavitt was appointed head of the Department of Stellar Photometry at Harvard Observatory in 1921, a few months before her death.
Gösta Mittag-Leffler, a Swedish mathematician, attempted to nominate her for the Nobel Prize in Physics in 1926. He was unsuccessful, as the prize could not be awarded posthumously. But an asteroid and a lunar crater were named Leavitt in honour of the astronomer.

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