A Celebration of Female Astronomers

Many women have contributed to our knowledge of astronomy. Here is a short list of four women astronomers from different time periods that made significant contributions.

Hypatia of Alexandria – 4th Century AD

Hypatia of Alexandria is regarded as the first woman astronomer. She lived during the late 4th, early 5th centuries. She taught mathematics, physics, and astronomy, and wrote many books about these subjects – thirteen books on algebra and another eight books on geometry.

Hypatia is known to have edited at least Book III of Ptolemy’s Almagest which supported the geoentric model of the universe shown in this diagram.[

Hypatia is known to have constructed an astrolabe, an instrument used to measure the positions of the stars. She used it to calculate the positions of specific stars, and then published her data in tables in The Astronomical Canon. Sailors and astronomers used her tables for the next 1200 years.

She also edited the third book of her father’s, Commentary on the Almagest of Ptolomy. The Ptolemaic model of the universe was geocentric where the sun was thought to have revolved around the earth. In the Almagest, Ptolemy proposed a division problem for calculating the number of degrees swept out by the sun in a single day as it orbits the earth. Hypatia’s contribution is thought to be an improved method for the long division algorithms needed for such astronomical computations.

Caroline Lucretia Herschel  1750 -1848

Caroline Herschel was a German astronomer and the younger sister of the astronomer William Herschel. She is best known for the discovery of several comets, including the periodic comet 35P/Herschel–Rigollet, which bears her name.

This image of Comet Herschel-Rigollet was obtained in August 11939. Copyright © 2010-2015 Hamburger Sternwarte, Fachbereich Physik, MIN-Fakultät, Universität Hamburg.

She was the first woman to be awarded a Gold Medal of the Royal Astronomical Society and to be named an Honorary Member of the Royal Astronomical Society. The King of Prussia presented her with a Gold Medal for Science on the occasion of her 96th birthday.

She independently co-discovered the galaxy M110 – this galaxy is a companion to the Andromeda galaxy M32 and was included in a sketch of M32 by Charles Messier but Messier did not include M110 in his original list. The suggestion to assign M110 a Messier number was not made until 1967.

Cecilia Helena Payne-Gaposchkin 1900 – 1979

Cecilia Payne was a British-born American astrophysicist who proposed in her 1925 doctoral thesis that stars were composed primarily of hydrogen and helium. In analyzing spectral absorption lines, she found that silicon, carbon, and other common metals seen in the Sun’s spectrum were present in about the same relative amounts as on Earth, in agreement with the accepted belief of the time. However, she found that helium and hydrogen were vastly more abundant – by a factor of about one million for hydrogen.

The sun’s visible absorption spectrum. Image credit: Rolf A. F. Witzsche

The astronomer Henry Norris Russell  convinced Payne to initially describe her results as “spurious” because the current scientific consensus was that the elemental composition of the Sun and the Earth were similar. In 1914, he had written:

The agreement of the solar and terrestrial lists is such as to confirm very strongly Rowland’s opinion that, if the Earth’s crust should be raised to the temperature of the Sun’s atmosphere, it would give a very similar absorption spectrum. The spectra of the Sun and other stars were similar, so it appeared that the relative abundance of elements in the universe was like that in Earth’s crust.[

A few years later, the astronomer Otto Struve described her work as “the most brilliant PhD thesis ever written in astronomy”. Russell, himself, ultimately realized she was correct and admiringly acknowledged Payne’s earlier work and discovery; but nevertheless, he is often credited for the conclusions she reached.

Jocelyn Bell Burnell 1943 –

Jocelyn Bell Burnell was awarded a $3-million Special Breakthrough Prize in Fundamental Physics in 2018. The prize committee not only acknowledges her discovery of the weird, fast-spinning stellar corpses known as pulsars but also her “lifetime of inspiring scientific leadership.” The discovery of pulsars was recognized by the award of the 1974 Nobel Prize in Physics, but despite the fact that she was the first to observe a pulsar, Bell Burnell was not one of the recipients of the prize – a point of controversy since then. But Bell Burnnell was not dismayed at the lack of recognition, saying instead

I believe it would demean Nobel Prizes if they were awarded to research students, except in very exceptional cases, and I do not believe this is one of them. Finally, I am not myself upset about it – after all, I am in good company, am I not!

In 1967, Bell Burnell was working with Anthony Hewish, an astronomer at Cambridge who wanted to find more quasars and needed a new radio telescope to do so. Bell Burnell helped build the radio telescope and after it was built, she was left as the first person to run the telescope. During the first six months, she discovered over 100 quasars but the real breakthrough first appeared on August 6, 1967. She noted an “scruff” that she later found appeared over and over again in the same part of the sky. Higher-speed recordings made in November 1967 revealed that Bell Burnell had captured a repeating string of radio pulses spaced a bit more than a second apart that were unlike anything seen before. Temporarily dubbed “Little Green Man 1” (LGM-1) the source, which is now known as PSR B1919+21,was identified after several years as a rapidly rotating neutron star.

Pulsar PSR B1509-58 – Image Credit: NASA/CXC/SAO (X-Ray); NASA/JPL-Caltech

Rotating neutron stars with regular rotational periods are called “pulsars” because the produce pulses of radio waves with a very precise intervals ranging from milliseconds to seconds. The precise periods of pulsars makes them very useful tools. They were used to indirectly confirm the existence of gravitational radiation. the first exo-planets were discovered around a pulsar,  and they can rival atomic clocks in their accuracy in keeping time.