Maria Mitchell (1818-1889)
Astronomer

Growing up in the whaling town of Nantucket, Massachusetts Mitchell grew up learning about the stars and navigation. She could rate the chronometers for whaling ships and plot the movements of the planets.

In 1847, her discovery of a comet invisible to the naked eye won her international fame and a medal from the king of Denmark. After that, she went to work for the U.S. Nautical Almanac Office to compute ephemeredes of the planet Venus.

When Vassar College was founded in 1865, she joined the faculty as a professor of astronomy and director of the college observatory. She became the first woman elected to the American Academy of Arts and Sciences, and founded the Association for the Advancement of Women in 1873, chairing the Committee on Women’s Work in Science until her death.

Women in Science: Rosalind Franklin (1920-1958)
Biophysicist

Franklin went to Newnham College, Cambridge and graduated in 1941, but was only awarded a degree titular, as women were not entitled to degrees from Cambridge at the time; in 1945 Franklin received her PhD from Cambridge University.

Franklin’s x-ray diffraction photographs led to the understanding of the structure of deoxyribonucleic acid (DNA). Her colleague, Maurice Wilkins, without obtaining her permission, made available to Watson and Crick her then unpublished x-ray diffraction pattern of the B form of DNA, which was crucial evidence for the helical structure of DNA.

Aside from her x-ray work with DNA, she also work with x-rays of lipids and proteins, and also did x-ray crystallography with the tobacco mosaic virus.

She studied at Cambridge as an undergraduate but was not awarded a degree because the university didn’t grant degrees to women at that time. After meeting Harlow Shapley, the Director of the Harvard College Observatory, who had just begun began a graduate program in astronomy, she left England for the United States in 1923.

Payne-Gaposchkin became the first person to earn a Ph.D. in astronomy from Radcliffe (now part of Harvard). By studying the spectra of stars, Payne-Gaposchkin determined that hydrogen and helium were the most abundant elements in stars. She was the first woman to receive the rand of full professor at Harvard and also the first woman chairperson of a department at Harvard University.