Ālenush Teriān was an Iranian-Armenian astronomer and geophysicist. She gained her PhD in Atmospheric Physics from @Sorbonne_U before becoming an Assistant Professor at @UnivOfTehran. She became the first female Professor of Physics in Iran in 1964. #STEMlegends #WomenInSTEM pic.twitter.com/hbbSjykrgW

— RAS Women in STEM (@RAS_Women) September 30, 2018

Asima Chatterjee was an Indian organic chemist who developed anti-epileptic drugs and anti-malarial drugs. She was the first woman to gain a Doctorate of Science from an Indian university in 1944, when she graduated from University of Calcutta.#STEMlegends #WomenInSTEM pic.twitter.com/GAf6cxYfFk

— RAS Women in STEM (@RAS_Women) September 29, 2018

Elizabeth Armstrong Wood was an American geologist. She earned her PhD in geology from @BrynMawrCollege, and became the first female scientist to work at @BellLabs in 1942. She wrote numerous books including Rewarding Careers for Women in Physics. #STEMlegends #WomenInSTEM pic.twitter.com/RMT5lySHGp

— RAS Women in STEM (@RAS_Women) September 28, 2018

Yvette Cauchois was a French physicist. She gained her PhD from @CNRS in 1933. She founded and directed the Centre de Chimie Physique in France in 1960 and was the second women to chair the French Society of Physical Chemistry after Marie Curie. #STEMlegends #WomenInSTEM pic.twitter.com/RD0MjKOjkY

— RAS Women in STEM (@RAS_Women) September 27, 2018

Flora Sadler was a British astronomer from Aberdeen. She graduated from @aberdeenuni in 1934, and travelled to Siberia to observe a total eclipse. She then worked at @ROGAstronomers and @RoyalAstroSoc. She was elected a Fellow of @RoyalAstroSoc in 1938. #STEMlegends #WomenInSTEM pic.twitter.com/KHyqUbYr8c

— RAS Women in STEM (@RAS_Women) September 26, 2018

Dorrit Hoffleit was an American astronomer. She earned her PhD at @RadInstitute and was hired as an astronomer at @Harvard in 1948, moving to @Yale in 1956 and working with Ida Barney. She also served as director of the Maria Mitchell Observatory. #STEMlegends #WomenInSTEM pic.twitter.com/G9rBnoXmaE

— RAS Women in STEM (@RAS_Women) September 25, 2018

Maria Goeppert-Mayer was a German-American physicist. She completed her PhD at @uniGoettingen in 1931, studying under Max Born. #STEMlegends #WomenInSTEM pic.twitter.com/mXgDQVi2QW

— RAS Women in STEM (@RAS_Women) September 24, 2018

Mayer’s thesis showed that atoms can simultaneously absorb two photons, transferring this energy to the atom's electrons. This was not confirmed experimentally until the 1960s. Mayer became a Senior Physicist at the @argonne in 1946. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 24, 2018

While at @argonne, Mayer developed a mathematical model that explained how the number of particles in an atom’s nucleus is related to the atom's stability. Mayer showed that the nucleus of an atom is a series of closed shells, and neutrons and protons undergo spin orbit coupling.

— RAS Women in STEM (@RAS_Women) September 24, 2018

Mayer won the 1963 Nobel Prize in Physics for her work on nuclear shells. This made her the second, (and also the last) woman to win the Nobel Prize in Physics, after Marie Skłodowska Curie, which Curie shared with Antoine Henri Becquerel and Pierre Curie in 1903. #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 24, 2018

Cicely Mary Botley was a British astronomer and science populariser from Hastings. She wrote numerous articles and two books. She was a member of @BritAstro, and became a Fellow of @RoyalAstroSoc in 1938. #STEMlegends #WomenInSTEM pic.twitter.com/uHdM6FN8iR

— RAS Women in STEM (@RAS_Women) September 23, 2018

Grace Hopper was an American mathematician and computer scientist. She gained a degree in mathematics and physics from @Vassar in 1928, and a master's and PhD from @Yale in 1930 and 1934. She became Associate Professor of Mathematics at @Vassar in 1941. #STEMlegends #WomenInSTEM pic.twitter.com/kXlWskUkRM

— RAS Women in STEM (@RAS_Women) September 22, 2018

During WWII, Hopper joined the @navy_reserve. In 1944, she joined the Computation Project at @Harvard as a Junior Lieutenant. Here, she programed the @IBM Automatic Sequence Controlled Calculator (ASCC), known as the Mark I. She coined the term 'debugging' in 1947.

— RAS Women in STEM (@RAS_Women) September 22, 2018

Hopper helped develop UNIVAC I in 1949, and developed the first compiler in 1952. She became the Director of Automatic Programming in 1954 and was largely responsible for the development of COBOL. Hopper retired in 1986, by which time she was a rear admiral.

— RAS Women in STEM (@RAS_Women) September 22, 2018

Anna Mani was an Indian physicist and meteorologist, specialising in solar radiation, ozone, and wind energy. She graduated from Presidency College, Chennai in 1939 and later studied at @iiscbangalore and @imperialcollege. #STEMlegends #WomenInSTEM pic.twitter.com/zrJ1bEBeFg

— RAS Women in STEM (@RAS_Women) September 21, 2018

Mani joined the Meteorological department in Pune in 1948, and was made head of the division within five years, with 121 men working for her. She became the Deputy Director General of the @Indiametdept in 1969 and served as a @WMO consultant in Egypt. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 21, 2018

Charlotte Moore Sitterly was an American astronomer who gained her degree from @swarthmore in 1920. She went on to work at @Princeton Observatory and @MtWilsonObs. While at @Princeton, she used spectroscopy to identify the chemical elements in the Sun. #STEMlegends #WomenInSTEM pic.twitter.com/Ub42a788ev

— RAS Women in STEM (@RAS_Women) September 20, 2018

Sitterly joined the National Bureau of Standards in 1945, and soon published tables on atomic spectra and energy levels, which remained in use for many decades. She was elected a Fellow @RoyalAstroSoc in 1949. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 20, 2018

Berta Karlik was an Austrian physicist. She earned her PhD at @univienna in 1928. She then worked on crystallography with Ellie Knaggs and Helen Gilchrist in London. She also corresponded with Marie Curie, Lise Meitner, Ellen Gleditsch, and Eva Resmtedt. #STEMlegends #WomenInSTEM pic.twitter.com/Ygtp99YtWU

— RAS Women in STEM (@RAS_Women) September 19, 2018

Sameera Moussa was an Egyptian nuclear physicist. She gained a BSc from @CairoUniv in 1939, followed by her PhD. She then became an assistant professor. Moussa specialised in nuclear medicine aiming to make it "as available and as cheap as Aspirin". #STEMlegends #WomenInSTEM pic.twitter.com/FkVT0SDrrA

— RAS Women in STEM (@RAS_Women) September 18, 2018

Kathleen Lonsdale was a British physicist. She graduated @ucl in 1924 and then joined the crystallography research team at @Ri_Science, where she became a pioneer of X-ray crystallography, using X-ray diffraction to determine the shape of molecules. #STEMlegends #WomenInSTEM pic.twitter.com/xgSRgLA3Qr

— RAS Women in STEM (@RAS_Women) September 17, 2018

Lonsdale became the first female Professor to gain tenure at @ucl. In 1966. She was elected the first female president of @IUCr, and she was elected the first female president of @BritSciAssoc the following year. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 17, 2018

Lonsdale now has a crater on Venus named after her, as well as Lonsdaleite, also known as hexagonal diamond. Lonsdaleite is formed when meteorites containing graphite strike the Earth. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 17, 2018

Cecilia Payne-Gaposchkin was a British-American astronomer. She studied at the @Cambridge_Uni in 1919. She earned her degree but did not receive it, as they did not grant degrees to women until 1948. She was elected a Fellow of @RoyalAstroSoc 1922. #STEMlegends #WomenInSTEM pic.twitter.com/Xm753jicfq

— RAS Women in STEM (@RAS_Women) September 16, 2018

Payne-Gaposchkin moved to the US in 1923, in order to complete her PhD at the Harvard Observatory. This was described by astronomer Otto Struve as "undoubtedly the most brilliant Ph.D. thesis ever written in astronomy". #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 16, 2018

Payne-Gaposchkin's PhD thesis related the spectral class of stars to their temperature, and showed that absorption lines vary because of different amounts of ionization at different temperatures, not because of different amounts of elements, as was previously thought.

— RAS Women in STEM (@RAS_Women) September 16, 2018

Payne-Gaposchkin used this information to correctly predict that common elements, like silicon and carbon, are found in the same relative amounts on the Sun as on Earth, but that the majority of the Sun's mass is made of helium and hydrogen, with much more of the latter.

— RAS Women in STEM (@RAS_Women) September 16, 2018

Astronomer Henry Norris Russell derived the same result four years later, and is often given credit for the discovery, although he acknowledged her work in his paper. After completing her PhD, Payne-Gaposchkin went on to study variable stars. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 16, 2018

In 1954, astronomer Donald Menzel became Director of the Harvard Observatory. He attempted to improve the status of women at the University and, in 1956, made Payne-Gaposchkin the first female Professor in the faculty. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 16, 2018

Katharine Way was an American physicist. She earned her degree at @Columbia and her PhD at @UNC, where she was supervised by John Wheeler. She joined the Manhattan Project in 1942, working for Wheeler with physicist Alvin Weinberg. #STEMlegends #WomenInSTEM pic.twitter.com/bgg68Sz6si

— RAS Women in STEM (@RAS_Women) September 15, 2018

Way used data that had been compiled by Enrico Fermi in order to show that it's possible to create a self-sustaining nuclear chain reaction. Her calculations were used to construct Chicago Pile-1, the world's first nuclear reactor. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 15, 2018

In 1946, Way co-edited One World or None: a Report to the Public on the Full Meaning of the Atomic Bomb. This contained essays by physicists like Niels Bohr, Albert Einstein, and Robert Oppenheimer. Way became a professor at Duke University in 1968. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 15, 2018

Mary Cartwright was a British mathematician. She gained her PhD at @UniofOxford in 1928. In the 1930s, she developed Cartwright's theorem, which is used in signal processing. She began collaborating with mathematician John Edensor Littlewood in 1938. #STEMlegends #WomenInSTEM pic.twitter.com/OtUZNVTSLR

— RAS Women in STEM (@RAS_Women) September 14, 2018

Cartwright and Littlewood were the first to analyse a dynamical system with chaos theory. Cartwright was the first female mathematician to be elected a Fellow of @royalsociety in 1947, and became the first female President of the @LondMathSoc in 1961. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 14, 2018

Vera Fedorovna Gaze was a Russian astronomer. She graduated from Petrograd University in 1924, and went to work at the Pulkovo Observatory and the Simeiz Observatory. She discovered about 150 nebulae, the minor planet Gase, and the Gaze Crater on Venus. #STEMlegends #WomenInSTEM pic.twitter.com/I32VC4popD

— RAS Women in STEM (@RAS_Women) September 13, 2018

Lorna Mary Swain was a British mathematician who studied at @Cambridge_Uni, graduating in 1913. During WWI, she worked at @Cambridge_Uni, researching propeller vibration in aircraft. She was elected a Fellow @RoyalAstroSoc in 1922. #STEMlegends #WomenInSTEM pic.twitter.com/ErsznmPNjW

— RAS Women in STEM (@RAS_Women) September 12, 2018

Evelyn Boyd Granville was an American mathematician. She became the second black American woman to gain a PhD in mathematics in the US at 1949, while she was at @Yale. She worked on several projects for the Apollo program in the 1960s. #STEMlegends #WomenInSTEM pic.twitter.com/Icqz4yUyZJ

— RAS Women in STEM (@RAS_Women) September 11, 2018

Kathleen Sherrard was an Australian geologist and paleontologist. She completed an MSc from @unimelb in 1921 and was a member of @RoyalSocietyVic and @GeoSocAustralia. She helped establish the Australian Association of Scientific Workers in 1939. #STEMlegends #WomenInSTEM pic.twitter.com/MYXIgJbBvN

— RAS Women in STEM (@RAS_Women) September 10, 2018

Katharine Burr Blodgett was an American physicist. She was the first woman to be awarded a Ph.D. in physics from @Cambridge_Uni in 1926, she worked for General Electric Laboratory, received eight patents over her lifetime, and may have been LGBT+. #STEMlegends #WomenInSTEM pic.twitter.com/N3ZTa154Ro

— RAS Women in STEM (@RAS_Women) September 9, 2018

Irène Joliot-Curie was a French chemist. She joined her mother Marie Skłodowska Curie at the Red Cross Radiology Service during WWI, when she was 18. She gained her PhD in 1925, and married Frédéric in 1926. The Joliot-Curies began collaborating in 1928. #STEMlegends #WomenInSTEM pic.twitter.com/IhzNrnuxu8

— RAS Women in STEM (@RAS_Women) September 8, 2018

The Joliot-Curies were the first to record evidence of the positron and the neutron. In 1934, they showed that radioactive materials could be created artificially, which allowed people to quickly create cheap radioactive materials used in medicine. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 8, 2018

The Joliot-Curies won the 1935 Nobel Prize in Chemistry for this, with Irène becoming the second woman to ever win the Prize. In 1938, Irène Joliot-Curie and Paul Savitch took the first step towards uranium fission, but their research was soon disrupted by WWII.

— RAS Women in STEM (@RAS_Women) September 8, 2018

During WWII, the Joliot-Curies joined the French Resistance. In 1946, Irène became director of the Radium Institute. She helped construct the first French nuclear reactor in 1948, and died in 1956. Like her mother, this was due to her long-term exposure to radiation.

— RAS Women in STEM (@RAS_Women) September 8, 2018

Julie Marie Vinter Hansen was a Danish astronomer. She worked as a ‘computer’ at @uni_copenhagen observatory in 1915, later becoming an observatory assistant and observer. She was elected a Fellow @RoyalAstroSoc 1931. #STEMlegends #WomenInSTEM pic.twitter.com/S0M8Xf7VYV

— RAS Women in STEM (@RAS_Women) September 7, 2018

Kathryn Peddrew was an American mathematician. She graduated from @StorerCollege in 1943 before working with other black women in a segregated area of NACA, which became @NASA in 1958. She was involved in many breakthroughs made during the space program. #STEMlegends #WomenInSTEM pic.twitter.com/gk4FuJlfM6

— RAS Women in STEM (@RAS_Women) September 6, 2018

Elizaveta Karamihailova was a Bulgarian physicist. She gained her PhD at @univienna in 1922, and stayed on at the Institute for Radium Studies, working with Marietta Blau. Karamichailova and Blau were the first to observe neutron radiation in 1931. #STEMlegends #WomenInSTEM pic.twitter.com/8cdIyRrEYT

— RAS Women in STEM (@RAS_Women) September 5, 2018

Hisako Koyama was a Japanese astronomer. She built her own Solar-telescope and began sketching sunspots in 1944, before being hired by the Tokyo Science Museum. Koyama published more than 8,000 sunspot groups and made over 10,000 sketches of the Sun. #STEMlegends #WomenInSTEM pic.twitter.com/ZMSCuiRq6t

— RAS Women in STEM (@RAS_Women) September 4, 2018

Ida Noddack was a German chemist and physicist. She gained her PhD from @TUBerlin in 1919. She went on to correct Enrico Fermi's chemical proofs in his 1934 paper on radioactivity, and was arguably the first person to describe nuclear fission. #STEMlegends #WomenInSTEM pic.twitter.com/tk3ZqGHxzm

— RAS Women in STEM (@RAS_Women) September 3, 2018

Noddack, her husband Walter, and fellow physicist Otto Berg claimed they had discovered two new elements in 1925: masurium (aka technetium), named after an area of Poland famous for its thousands of lakes, and rhenium, named after the river Rhine. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 3, 2018

Noddack was nominated for the Nobel Prize in Chemistry three times, in 1933, when no prize was given, in 1935, when she lost to Irène and Frédéric Joliot-Curie, and in 1937, when she lost to Walter Norman Haworth and Paul Karrer. #STEMlegends #WomenInSTEM

— RAS Women in STEM (@RAS_Women) September 3, 2018

Inge Lehmann was a Danish geophysicist and head of the Department of Seismology at the Geodetical Institute. She was the first to explain P waves and discovered that the Earth has a solid inner core in 1936. She became a Fellow @RoyalAstroSoc in 1936. #STEMlegends #WomenInSTEM pic.twitter.com/CX8ly4tUhj

— RAS Women in STEM (@RAS_Women) September 2, 2018

Ellen Louise Mertz was a Danish geologist and engineer. She worked for the Geological Survey of Denmark and the Danish State Railways, before pioneering geophysical engineering and helping construct eight bridges, including Little Belt Bridge in 1929. #STEMlegends #WomenInSTEM pic.twitter.com/kFjGhg1enk

— RAS Women in STEM (@RAS_Women) September 1, 2018