A supernova in needlepoint

532627I hate to admit that I didn’t know a thing about the amazing astronomer and astrophysicist Cecilia Payne-Gaposchkin until I stumbled on an archival photograph of her less serious work with needle and thread (also impressive). Pictured above is her X-ray image of the Cassiopeia-A supernova rendered in needlepoint.

Payne was the first to work out the correct answer to the simple and profound question: What are the stars made of?

Cecilia Helena Payne Gaposchkin
Cecilia Helena Payne Gaposchkin

Hydrogen, mostly, she determined through an inventive and rigorous analysis of the spectra of light from stars. It was a pivotal finding at odds with expert opinion in the 1920s, when she published the work in a doctoral dissertation at Harvard University. Astronomers were convinced that iron and other heavy elements abundant on Earth were equally abundant in stars. Princeton astronomer Henry Norris Russell asserted that if the Earth’s crust were heated to a solar temperature, it would emit light with a spectrum like the sun’s.

Payne discovered that the composition of stars is vastly different, with hydrogen about a million times more abundant than the heavier elements common on Earth. Wanting confirmation for so revolutionary a claim, Harvard College Observatory director Harlow Shapley sent Payne’s thesis to Princeton’s heavyweight astronomer, Russell, who dismissed her result as “clearly impossible.” Payne dutifully inserted a statement in her thesis that the calculated abundances of hydrogen and helium were “almost certainly not real.”

Within a few years, Russell realized Payne’s calculations were on the mark when his analysis of the data took a different route to the same conclusion. Russell promptly took credit, publishing his finding with barely a nod to Payne. (Princeton still credits him as the sole discoverer.)

Persistently and gracefully, it seems, Payne overcame such obstacles her whole life. A native of England, she won a scholarship to Newnham College, Cambridge University, where she completed studies but was not awarded a degree because Cambridge did not give them to women until 1948. At Harvard, she lectured, advised students, and conducted research unofficially and without acknowledgement until 1938 when she was granted the title of astronomer. None of the courses she taught at Harvard were recorded in the catalogue until 1945. Harvard waited until 1956 to make her a full professor. She was the first woman to gain that title there.

She crafted the needlepoint in 1975. It being the 70s, her friend and colleague John R. Whitman had to use a giant mainframe computer at the Smithsonian Institution’s Center for Short-Lived Phenomena to output the schematic below. The remnant of a very recent supernova, Cassiopeia A was first detected in 1947. Astronomers figure its explosive expansion would have become visible to Earth-bound observers in the year 1667.


[Hat tip to True Anomolies]


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