Brilliant Women Helped Lay the Foundation of Astrophysics

I enjoyed the Princeton Portrait in November’s PAW on the celebrated astronomer and astrophysicist Henry Norris Russell. But I wanted to put in a corrective note about his determination of stellar composition. The story is a little more tangled.

The first person to advance the idea (which her research had established) that hydrogen was the dominant material in stars was Cecilia Payne, a Cambridge-educated British astronomer who came to the other Cambridge to earn a Ph.D. in astronomy at Radcliffe, as the original Cambridge at the time would not afford her the opportunity.

Russell, though at Princeton, was asked to be on her thesis committee. By many accounts, Russell cautioned her from claiming hydrogen as the dominant material in stars, as this was contrary to then-current wisdom. So she soft-pedaled the claim, even suggesting that her own data had to be wrong. Russell’s criticism may have been meant kindly, to keep her thesis from being rejected; it’s hard to know. Four years later he arrived at exactly the same conclusion and acknowledged her earlier claim in print. However, this did not prevent future writers from assigning credit to Russell alone for the discovery.

Some eight years after her doctorate, Dr. Payne met and married a Russian astronomer, Sergei I. Gaposchkin, and is usually known today as Cecilia Payne-Gaposchkin. She eventually became a professor at Harvard, much with the support of Russell’s student Donald H. Menzel (Princeton *1924), who was tenured at Harvard.

Russell is perhaps better known as a co-discoverer, with Ejnar Hertzsprung, of the Hertzsprung-Russell diagram linking luminosities to temperatures. This diagram too is based heavily on the work of a woman astronomer at Harvard, Annie Jump Cannon, who had categorized stars according to a color scale which became standard.

These and many other stories are told by Dava Sobel in her history The Glass Universe.

Despite my loyalty to Princeton, I admire Harvard Observatory director Edward C. Pickering’s foresight to employ dozens of brilliant, highly educated women in what many would have found mindless toil. These women, not nearly as well-known as they should be, founded astrophysics. To this day, in my opinion, the least sexist branch of physics remains astrophysics, maybe because the sky is open to all. Happily, things are changing, and the rest of physics is making slow but steady progress toward equality.