Monday, March 13, 2017

Something New

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We feature each week Nicholas Reid's reviews and comments on new and recent books.

“THE GLASS UNIVERSE” by Dava Sobel (4th Estate – Harper/Collins, $NZ36:99)

            Astronomy made great advances in the 19th century when photography came to its aid and astrophotography was born. Telescopes in observatories were organised to defy the rotation of the Earth and to stay focused on just one area of the night sky. Cameras fitted with specially prepared glass plates could now capture images of greater detail and clarity than a naked eye could see when pressed to the telescope eyepiece. An English firm perfected new dry (and chemically infused) plates, which meant that astronomers themselves no longer needed to treat their photographic plates with chemicals. Stellar spectroscopy allowed astronomers to work out the chemical substance of stars through their colours.

            The new precise and detailed photographic images of the stars were the “glass universe” of science-writer Dava Sobel’s latest work. The heavens suddenly seemed crowded as astronomers could observe far more than had ever previously been seen.  One picture in the 1880s “yielded 462 stars in a region where only 55 had been previously documented.” (p.19)

Nowhere was astrophotography taken up with such enthusiasm as at the observatory of Harvard University between the 1880s and the 1920s. “In less than a decade at the helm,” says Dava Sobel, “[Professor] Edward Pickering had shifted the observatory’s institutional emphasis from the old astronomy centred on star positions, to novel investigations into the stars’ physical nature.” (p.21)

It was men who watched the night skies, organised the telescopes and took most of the photographs – the type of men who won prizes and fellowships and became professors. But increasingly it was women who went through the business of analysing the glass plates and working out the magnitude, position, motion, brightness, colour and position on the spectrum of the stars observed. Comparing different photographic glass plates of the same area of sky, women were also assigned the task of hunting for “variables” – those stars whose brightness changed, possibly because they were part of a binary system or because they were emitting light at different rates in keeping with some process of growth or decay.  

Odd as it now sounds, the women who scrutinised the plates were called “computers”. They computed the distances, magnitude etc of stars. As observation became more precise, as tens of thousands of stars were observed for the first time, and as the sheer variety of stars became known, whole classification systems had to be altered and revised. These “computers” were at the forefront of devising the new systems of classification and hence of re-writing academic astronomy books.

You will now understand why Dava Sobel subtitles The Glass Universe  “The Hidden History of the Women Who Took the Measure of the Stars”. Her declared purpose is to bring to light those pioneering women in American astronomy who did the hard analytical work, in some cases without great public recognition, while the men who ran the astronomical institution often received the kudos.

She tells the stories of many such women.

There was, for example, Antonia Maury, of whom Sobel remarks  “Her two-tiered classification system, which addressed both the identity and the quality of the spectral lines, required a painstaking exactitude.” (p.49) Those last two words, “painstaking exactitude”, characterise much of the work of the “computers”. Glass plates were scrutinised in minute, indeed microscopic, detail, and stars reclassified according to systems that required multiple digits.

There was “Mina” (Williamina) Fleming, who classified over 10,000 stars, discovered ten novae and over 300 variable stars. Fleming was made “curator of astronomical photographs” and was therefore the first woman to hold a title at Harvard – but she was granted a lower rate of pay than her male colleagues.    

“ ‘In the Astrophotographic building of the Observatory,’ [Fleming wrote on] March 1 1900, on a lined yellow notepad, ‘12 women, including myself, are engaged in the care of the photographs; identification, examination and measurement of them; reduction of these measurements, and preparation of results for the printer.’ Every day they bent to their examination tasks in pairs, one with a microscope or magnifying glass poised over a glass plate in its frame, and the other holding a logbook propped open on a desktop or in her lap, recording the spoken observations of her partner. A hum of numbers and letters, like conversations in code, pervaded the computing room.” (p.89)

There was Annie Jump Cannon, who classified many hundreds of thousands of stars and devised the index system “OBAFGKM” which is still used by astronomers. Though it might now be condemned as “sexist”, it was Annie Cannon herself who made up the mnemonic for her index system: “Oh Be A Fine Girl, Kiss Me.”

Some of the women Sobel chronicles came from humble backgrounds, including a maidservant, but many came from the newly established colleges for women. Even if they were not paid well, they found the Harvard observatory one of the few places where they could gain meaningful employment in research. In fact some women college graduates begged to be employed for free, such was the prestige of the institution. But Mina Fleming “did not consider it good policy to place the observatory under obligation to anyone for services rendered gratis.” (p.105)

As well as the “computers” Maury, Fleming, Cannon and others, there was another class of women who influenced American astronomy. These were the benefactors, such as Catherine Wolfe Bruce, a wealthy widow who donated her astronomer husband’s advanced telescopes to Harvard; and Anna Palmer Draper, the widow of the wealthy man who basically invented astrophotography and who funded the Harvard work. The constant search for funds is one sub-theme of this book, with Professor Pickering often writing begging letters to the likes of Andrew Carnegie.

To remember innovators in science is obviously a worthwhile thing and Dava Sobel makes a good case for the patient, methodical, observant and highly focused women whom she praises. It is often a matter of recording their careful movements, as in the following precise passage:

Miss Fleming removed each glass plate from its kraft paper sleeve without getting a single fingerprint on either of the eight-by-ten-inch surfaces. The trick was to hold the fragile packet by its side edges between her palms, set the bottom – open – end of the envelope on the lip of the specially-designed stand, and then ease the paper up and off without letting go of the plate, as though undressing a baby. Making sure the emulsion side faced her, she released her grip and let the glass settle into place. The wooden stand held the plate in a picture frame, tilted at a forty-five degree angle. A mirror affixed to the flat base caught daylight from the computing rooms big windows and directed illumination up through the glass.  Mrs Fleming leaned in with her loupe for a privileged view of the stellar universe. She had often heard the director say ‘A magnifying glass will show more in the photograph than a powerful telescope will show in the sky.’ ” (pp.25-26)

By this stage, you are probably persuaded that this is a very worthwhile book. It praises science, it gives an important role to women, its heart is in the right place.

But there are a couple of difficulties in the articulation of Sobel’s feminist theme. First there is the obvious fact that, once the “computer” women are factored in, the progress of astronomy was dependent on both sexes. As an experienced science-writer, Sobel author is fascinated by astronomy itself and its results. Hence, willy-nilly, the book becomes a history of men as much as of women and frequently wanders away from the Harvard “computers”.

Second, unlike her earlier best-selling book Longitude, this book cannot focus on one person and gradually becomes an institutional chronicle, with much information on who was appointed when, what departmental rivalries were going on, and other – not particularly enlightening - detail. In the story of many women’s toil, there is no single breakthrough or “Eureka!” moment; no climax to which the story can build; and hence much dull plodding.

I found myself frequently snatching at the incidental details on the periphery of Sobel’s main narrative. It was amusing to read of Harvard’s (eventually successful) attempts to set up a subsidiary observatory in the clear air of Peru while an armed uprising was going on in that country. There are tantalisingly brief references to the eccentric Percival Lowell, and to Professor Edward Pickering’s younger brother William Pickering, both of whom became obsessed with the notion of “canals” on Mars and even sent articles to credulous newspapers about vegetation on the moon – much to the consternation of more level-headed astronomers. There was the way international events disrupted research. During the First World War, American and British astronomers were separated from their valued German counterparts, meaning they had to catch up with the latter’s observations years after they had been made. This disruption was part of the reason that the great English astronomer Arthur Eddington (the man who confirmed Einstein’s theory of light by astronomical observation) became a lifelong pacifist. And towards the end of Sobel’s narrative, there was, from 1918 through the 1920s, the battle among astronomers over whether the universe was just one huge galaxy of stars; or whether our Milky Way galaxy was simply one galaxy among millions. This academic battle was stimulated by the earliest observations, thanks to astrophotography, of spiral nebulae.

The Glass Universe is a book packed with such interesting information, but in the end, it is a noble and worthy piece of work rather than an intellectually stimulating one. It walks patiently from datum to datum – a bit like the women whom it celebrates.

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