31 March 2010
March in National Women’s History Month in the USA. This year the theme is “Writing Women Back into History” (more info here). I was part of a swap where we were to send postcards honoring women scientists. Mine features an astronomer named Henrietta Leavitt. The way I found her was rather serendipitous – I was flipping through a volume of an old Golden Book Encyclopedia that I acquired for the express purpose of reusing in papercrafts. My eye was captured by the Cepheids constellation piece while I was looking for light blue pieces. Then I stopped to read the article. I don’t remember what it was in there, but it made me wonder “does this still apply, or do we know more about it now?”
In the process of answering that (now forgotten) question, I learned about Henrietta Swan Leavitt. Way back in the early 1900s, she was part of the “computer” team (nearly all women) at the Harvard Observatory. Her job was to look over photographic plates (taken by their telescope in Peru) and catalog stars on them. In the process, she became responsible for identifying the period-luminosity relation of Cepheid stars. This relationship can be used for determining the distance to stars, and was ground-breaking work that was built upon by Edwin Hubble and others. During her career, she discovered over 2,400 variable stars, roughly half the known total in that era. But the director she worked for did not recognize her skill, or if he did, he was not willing to let her do her own research. Henrietta Leavitt died in 1921 from cancer. Swedish mathematician Gosta mittag Leffler wrote to the current director of the Harvard Observatory in 1926, because he was unaware of her death and was interested in nominating her for the 1926 Nobel Prize in Physics. As the Nobel is not awarded posthumously, she was never so recognized.
Postscard assembly: the background is a plate of the large magellenic cloud as it appeared in her publication. Photos of Henrietta and the Harvard telescope in Peru are from wikimedia. The colorful images in the top right and bottom left come from the Golden Book encyclopedia that sent me on this mission of discovery, as does the text/explanation that appears in the form of a packing tape overlay on top of the graph.
Some sources I consulted:
- Inventor of the Week archive at MIT (“Henrietta Swan Leavitt invented one of the most essential standards in the study of space: a rule that allows astronomers to measure distances from Earth to various stars. … Her rule allowed for the mapping of the universe, as well as the discovery that it is expanding, and has made her a legend in the history of astronomy.”)
- “She is an Astronomer” web site
- Australia Telescope Outreach and Education – good explanation of the relationship she discovered and how later astronomers built on it.
- PBS Science Odyssey bio – (“Because of the prejudices of the day, she didn’t have the opportunity to use her intellect to the fullest, but a colleague remembered her as “possessing the best mind at the Observatory,” and a modern astronomer calls her “the most brilliant woman at Harvard.” “)