Sacred Space Astronomy readers, if you want to read a good book, try Attention is Discovery: The Life and Legacy of Astronomer Henrietta Leavitt, by Anna Von Mertens, published by MIT Press (2024). It’s the best book I have seen in a while.
Von Mertens is an artist. If you’re thinking, “oh no, some artist who thinks astronomy is cool but is really going to have no idea of what astronomers actually do”, think again. Some of her artwork consists of reproducing by hand the photographic plates used by Leavitt and the other Harvard Computers like Wilhelmina Fleming and Annie Jump Cannon. Von Mertens has thus taken a very close look at the data these people worked with. The reader of her book will find that she clearly has spent enough time with the material to have a really good grasp of what was going on in astronomy in Leavitt’s world. And, no doubt in part because Von Mertens is an artist, the book just looks great.
Von Mertens knows, and makes sure that her reader knows, just what Leavitt and her colleagues accomplished. Leavitt — a woman of faith (p. 25), described by a colleague as “deeply concientious and sincere in her attachment to her religion and church [p. 62]” — discovered the relationship between the periods of the fluctuations in brightness of Cepheid variable stars, and the overall luminosities of those stars. (“Cepheid” variables are those that fluctuate in brightness in the manner of a certain star in the constellation of Cepheus, delta Cephei.) Leavitt’s stars became the first “standard candles” — objects of known brightness that could be used to measure vast distances in the universe. Edwin Hubble used Leavitt’s Cepheids to show that the “spiral nebula” M31, visible to the naked eye (larger than the moon!) in the constellation Andromeda was located well outside our Milky Way galaxy, and thus was itself another galaxy — and so were other spiral nebulae. Although we tend to think of the astronomers at the telescope, like Hubble, as being the ones who make the big discoveries, astronomers came to realize that we live in a universe of galaxies because Leavitt noticed that relationship.
Von Mertens writes (pages 13-14, 18),
Noticing might seem to be passive, an act of stumbling across something and remarking on it. But after stating that the variables with the lengthiest periods appeared to be as consistent in their cycles as variables that repeat their pattern in just a day or two, any notion of passivity is dispelled by the next sentence in Leavitt’s paper: “This is especially striking in the case of no. 821, which has a period of 127 days, as 89 observations with 45 returns of maximum give an average deviation from the light curve of only six hundredths of a magnitude.” Eighty-nine observations of a single variable (amid the finding of 1,777 of them) to confirm the minutest fluctuation of light is not passive. And the pieces of data Leavitt extracted from her observations are not like consecutive words in a sentence that could be read one after the next. Leavitt describes the pattern of a Cepheid variable’s light as “diminishing slowly in brightness, remaining near minimum for the greater part of the time, and increasing very rapidly to a brief maximum,” but with each observation of a variable, she never knew where she had landed on that curve or how extended that curve was through time. She had to gather random fragments with sustained attention and carry them with her as she searched through time, negotiated technology, and amid the immensity, not despair. Leavitt figured out how to place these pieces of information to construct an understanding. Noticing is a wielded skill. … [The usual narrative] could easily be flipped: Leavitt was the visionary; Hubble just followed through on the details.
Von Mertens understands what Leavitt was doing and how much brain power was involved. Von Mertens identifies Leavitt as an astronomer — that’s how Leavitt identified herself (p. 178). No, Leavitt did not use a telescope; she analyzed data acquired by others. At that time, it was felt that women shouldn’t be at the telescope, because it wasn’t safe. But, as Von Mertens points out (p. 82), while it may not have been permitted for Leavitt to use a telescope, she understood how to use one. She suggests experimenting with the position of “the auxiliary prism” on one telescope to improve results. She suggests sequences of exposures. She suggests photographs for “determining the relative absorption in different parts of the objective” of a specific telescope. Lots of astronomers today don’t operate telescopes themselves. Like Leavitt, they analyze data acquired by others (data from the James Webb Space Telescope, for example). Lots of modern astronomers don’t have the sort of knowledge of the workings of the instruments that collect their data that Leavitt demonstrates.
My only complaint with the book has to do with its discussion of women. Von Mertens works hard to communicate the importance of women to astronomy in Leavitt’s time. It wasn’t just the Harvard Computers who were women contributing to astronomy; there were people like Anna Palmer Draper and Catherine Bruce who funded astronomy. Such funding meant that the director of the Harvard observatory had access to far more cash than he could raise through, for example, selling the grass clippings from the observatory’s grounds (yes, he did that — p. 51). If you ever see a star identified as, for example, HD 81797, that HD means the Henry Draper catalog. But Henry died in 1882; the catalog began to be published in 1918. The work was funded by Anna, in memory of Henry.
And yet… Von Mertens writes at one point of these women exhibiting “restrictive reasoning” and being “caught in the confines” of their time (p. 50). This in response to some women astronomers writing about women being trained for astronomical work thanks to girls being taught from a young age to do careful detail work, such as in sewing. Maria Mitchell wrote that “the taking of small stitches, involving minute and equable measurements of space, is part of every girl’s training; she becomes skilled, before she is aware of that, in one of the nicest peculiarities of astronomical observation.” This is “restrictive reasoning” to Von Mertens. Even she sometimes cannot accept these women on their own terms, and grant that Mitchell might actually know of what she speaks. Who today can judge whether needlework was indeed better training for astronomy than, say, calculus? Nobody is trained like that in needlework now. How can Von Mertens judge Mitchell from across more than a century as showing “restrictive reasoning”? But this very good book is not undone by one annoying page. Well, actually, there’s another (p. 106). It stereotypes, if you can believe it, what the women wore and how they did their hair! (And the women in the photos of the book don’t even match the stereotype.)
But these flaws do not prevent the book from painting a convincing picture of Henrietta Leavitt and her colleagues as being ground-breaking and brilliant astronomers, worthy of celebration along with the usual “greats” of astronomy. The book is well written and beautifully illustrated — it just oozes coolness.
A lot of those beautiful illustrations are of the photographic plates that held all the astronomical data that Leavitt studied. They’re pretty amazing. Some of the plates, those from the Bruce telescope, measured 14 x 17 inches (35 x 42.5 cm), covering Rubin-telescope-sized swaths of the sky! — and holding a boatload of analog data. And they last. They endure. They still exist and are usable. How usable will be the digital data of today in the year 2150? I have a bunch of stuff on CD-ROM (not two decades old) and not one computer with a CD-ROM drive to read it.
Read Attention is Discovery. I think you won’t be disappointed. If you are, let me know why! You can log in and leave comments, you know!
