Consideration Is Discovery, visible artist Anna Von Mertens’s considerate new exploration of astronomer Henrietta Swan Leavitt, describes and illuminates Leavitt’s decades-long research of stars, together with the groundbreaking system she developed for measuring huge distances inside our universe just by photographic plates. Leavitt studied tons of of 1000’s of stars captured on the glass plates on the Harvard School Observatory, the place she labored as a human laptop from the flip of the twentieth century till her dying in 1921. Von Mertens explores her life, the ladies she labored alongside and her discoveries, weaving biography, science and visible imagery right into a wealthy tapestry that deepens our understanding of the universe and the ability of targeted, methodical consideration.
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TRANSCRIPT:
Anna Von Mertens: Hubble’s discovery was not potential with out Leavitt’s work. It’s Leavitt’s work that started this understanding of our three-dimensional universe.
Carol Sutton Lewis: I am Carol Sutton Lewis, and that is “Misplaced Ladies of Science Conversations,” a collection the place we speak to writers, poets, and artists who give attention to forgotten feminine scientists.
Within the late 1800s, the size of the cosmos was unknowable. However this all began to alter on the flip of the twentieth century with the meticulous calculations and shrewd observations of astronomer, Henrietta Swan Leavitt. Leavitt, a “human laptop” on the Harvard School Observatory, pouring over glass plate images of the sky, found a system for measuring huge distances inside our universe.
She turned what had been as soon as unreachable areas of the cosmos right into a measurable map of stars, utilizing the ability of consideration.
For Anna Von Mertens, a visible artist based mostly in New Hampshire, the ability of consideration was nothing new. Anna makes work that investigates science and historical past, and her use of paper and pencil or thread and material requires time, endurance and intense focus. And so when she got here throughout Henrietta Leavitt’s work, she instantly felt a kinship. After spending many hours within the archives wanting on the examples of early astrophotography, which Leavitt used to make her astral discoveries, Anna created graphite drawings of glass plates and hand stitched quilts impressed by Leavitt’s legacy.
And, going even additional, she determined to jot down a guide that merges these visible works with lyrical and detailed essays that delve into Leavitt’s science. That guide, “Consideration Is Discovery: The Life and Legacy of Astronomer Henrietta Leavitt,” got here out in September, and it is the subject of our dialog at present.
So let’s get into it. Hello, Anna. Thanks for coming onto the present.
Anna Von Mertens: Hello, Carol. Thanks a lot for that pretty introduction.
Carol Sutton Lewis: Anna, you are an artist recognized on your use of varied textile processes and quilt making methods. So, how did you resolve to jot down a guide about Henrietta Swan Leavitt?
Anna Von Mertens: In order a visible artist, my work usually makes use of observable phenomena, patterns in nature that reveal structural revelations and understandings.
And so due to one of these work that I do that’s so steeped in historical past and science, I used to be invited by Jennifer Roberts to the Harvard Radcliffe Institute, and Jennifer was the Director of Arts on the time there, and she or he invited me to develop a research-based exhibition.
And the varied archives and libraries on campus at Harvard College had been generously opened as much as me to analyze as a potential topic for this exhibition. And we toured beautiful archives. However once I arrived on the Harvard School Observatory, I knew I had discovered my material.
As a result of there, housed, are over 550,000 glass plate images of the night time sky. Now that is the oldest and largest archive of these kind of images on this planet. And Harvard, being Harvard, established an observatory within the nineteenth century in Peru. In order that archive covers each the northern and southern hemispheres, and it is the one full document of the sky.
So viewing a few of these glass plate images, I first heard Henrietta Leavitt’s identify. I had by no means heard her identify earlier than. And thru these objects, these glass plates, I realized of her identify and realized of her discovery and struck by its significance–struck by the profundity of her discovery–I knew that I wished to develop a mission round her life and work.
Carol Sutton Lewis: And what a mission it’s. The guide can be a fantastic, uncommon mixture of artwork and science.
It is a very detailed rationalization of Henrietta Swan Leavitt’s work and the influence it had on science, nevertheless it’s additionally a phenomenal, creative interpretation of the glass plates that you simply noticed. And I might go on and on about this guide, however we’ll come again to it in a bit. Let’s speak somewhat bit about Leavitt herself. She got here to work on the Harvard School Observatory within the Eighteen Nineties.
What was recognized about our universe then?
Anna Von Mertens: Proper. Leavitt studied these images of the night time sky, however virtually nothing was recognized concerning the stars that shone in that night time sky. So on the time of Leavitt’s analysis, there was no sense of the chemical composition of the celebrities, and no option to understand how far-off these lights had been from us. So for instance, if a vibrant mild shone within the sky, did that imply that it was intrinsically bigger and brighter? Or did that imply merely that it was of equal brightness to a dim star, however merely nearer to us? So there was no sense of depth to the celebrities. There was no sense of construction to this sea of stars that we had been swimming in.
Carol Sutton Lewis: And inform me somewhat bit extra concerning the Harvard School Observatory. How did they arrive to be on the slicing fringe of astronomical analysis? I imply, what had been they doing that the others weren’t?
Anna Von Mertens: So the glass plate images that Leavitt studied had been a brand new type of know-how, dry plate images, and beforehand its predecessor, moist collodion images. An astronomer would wish to coat a glass floor with an emulsion, expose it to starlight by means of a telescope’s lens, after which develop that {photograph} all inside a span of quarter-hour, however with dry plate images–a way more steady substructure–that enabled exposures that had been a number of hours in size.
And so with that accumulation of starlight onto the glass floor, these dim stars could possibly be pulled into view over an publicity that is perhaps as much as 4 hours size in time. And so with this new know-how, a survey of the celebrities was potential beforehand, proper?
It will be depending on a single particular person’s eye wanting by means of a telescope, learning a person object and discovering observations on that particular person celestial object. Right here the celebrities could possibly be studied en masse. So, Edward Pickering, who was the director of the Harvard School Observatory on the time of Leavitt’s research, he realized that, that no astronomical analysis might transfer ahead with out constructing an empirical basis of data that future discoveries could possibly be created from. So he rapidly adopted this new know-how, dry plate images.
And with these glass plates, an enormous inundation of knowledge. It was the primary form of flood of massive knowledge into the sphere of astronomy. So with that inflow of knowledge, after all, a workforce was wanted to course of that knowledge. And Edward Pickering, regardless of being at Harvard, didn’t have an infinite funds. There was no funding from the faculty. He needed to merely function the observatory, based mostly on curiosity from the observatory’s endowment. So he needed to be fairly frugal in how he proceeded. And he realized that girls as a labor pressure could possibly be employed extra cheaply than males, and so they might analyze these glass plates, once more, form of organizing the information on them in order that they could possibly be extra available for research. One of many issues I really like about serious about Leavitt and form of this entry level to the science is that Pickering opened the door to it. It jogs my memory of this concept of a “Room of One’s Personal.”
So right here Leavitt and her feminine colleagues, that they had a constructing of their very own. So actually solely girls throughout her time labored within the brick constructing the place the glass plate assortment was housed. Now, sure, they had been cataloging this knowledge, however given entry to this knowledge and actually given company inside their work from the director, these girls not solely organized the information, however inside that shut proximity to the information, went forward and made the discoveries in their very own proper.
Carol Sutton Lewis: And so Anna, initially, what was Leavitt requested to do? What was her activity inside the observatory, inside this group, this constructing of girls?
Anna Von Mertens: So, nothing was recognized concerning the stars at the moment, and director Edward Pickering wished to survey the celebrities, and essentially the most fundamental aspect of the star, the data that could possibly be gleaned, was the brightness of that star. So, Leavitt was tasked with attempting to evaluate the magnitude, the brightness of every particular person star.
And this appeared easy sufficient. But when you consider what she needed to navigate, it’s an extremely nuancing, advanced. So the {photograph} was made by coating a glass plate with a lightweight delicate emulsion. That plate was positioned within the telescope and gathered starlight on its floor.
It was then developed and every star would register as a tiny black speck of emulsion. In the event you consider pepper form of scattered throughout the floor of a glass plate which may form of give a way of the minute particulars that she wanted to review. So a lot of the plates she studied had been photographic negatives with every star represented as a tiny speck of emulsion.
And so she went about assessing the magnitude of every star by measuring, estimating the form of diameter of every circle, of every tiny speck. Including complexity to this activity, the photographic medium was nascent and unreliable. And so for instance, outcomes would deviate from the middle of a glass plate merely to its edges.
Additionally the colour of starlight would have an effect on its outcomes on glass. So for instance, crimson stars barely registered with this new medium. And most importantly, Leavitt needed to collect info of images made by varied telescopes, made by totally different telescopes, created from totally different publicity instances, so evaluating a 15-minute publicity taken by one telescope to a 3 hour publicity taken by one other telescope, so she actually needed to first perceive this new translation of starlight onto glass. After which as soon as she had shaped that understanding, she might go and additional her analysis.
Carol Sutton Lewis: And within the midst of all this meticulous work, what did Leavitt uncover? What did she study concerning the cosmos?
Anna Von Mertens: So on this work of attempting to evaluate their particular person brightness and survey the celebrities, Leavitt seen that a few of these stars modified of their brightness, so referred to as variable stars.
So as an alternative of a constant quantity of sunshine, over time that mild would shift brighter, after which dimmer, after which brighter once more. And on the time Leavitt started this analysis, solely a number of hundred variable stars had been even recognized. However Leavitt made this a selected avenue of her analysis, and one of the crucial ingenious methods of hers that she developed to determine these variable stars, was to take a glass plate unfavorable of a sure patch of sky.
And, keep in mind, so every star would register as a black speck of emulsion. After which she would take one other {photograph} of that very same patch of sky, however on a distinct night time. And he or she would translate that unfavorable right into a optimistic. She would then superimpose a optimistic and unfavorable glass plate of the identical patch of sky taken on totally different nights.
And, if it was a standard star, it might simply, proper, these specks would fill within the holes on the optimistic and cancel one another out. However a variable star may announce itself as a tiny white halo of sunshine. And if that indicated that it could possibly be a variable, she would undergo time, undergo plates and attempt to monitor that altering mild by means of time. Now, as I stated, just a few hundred variable stars had been recognized initially of Leavitt’s analysis. In her lifetime, Leavitt personally found 2,400 variable stars, which is greater than half of all recognized variables on the time. So she was the resident professional on this area of analysis.
Carol Sutton Lewis: That’s unimaginable. So, in your guide, you lay out all the numerous inconsistencies of early astrophotography, the plate defects, the differing publicity instances, the blurry edges, emulsions, as you stated, with totally different response speeds.
She needed to take all of these potential inaccuracies into consideration when she was doing this evaluation, which brings me to the title of your guide, “Consideration is Discovery.” So why do you suppose the work of noticing the work of discovering patterns was so necessary to her work? I imply, clearly she might have simply been cataloging this, however why do you suppose that the noticing, helped her make these discoveries?
Anna Von Mertens: Nicely when one thing is understood, when a scientific discovery is introduced, it may well appear virtually self-evident. Like there’s such a readability to its reality, and one can, uh, see and observe that reality. And so it is useful to form of return deeper into Leavitt’s methodologies to know actually how there have been no guideposts. There have been no orientation markers to navigate the ocean of knowledge. So inside that you must actually think about the method of – take an remark, see what you may pull from that, after which repeat that motion. And you must have this, this form of fluid forwards and backwards the place you’re open to investigation.
You are not closing off sure strains of analysis, however you may have this receptivity to what you’re seeing, however then you definately’re permitting that seeing to information you. And so, Leavitt did precisely that in her groundbreaking discovery is that whereas she was working, whereas she was learning variable stars, she determined to show her consideration to the small Magellanic cloud.
Now this can be a celestial object that we now know as a satellite tv for pc galaxy separate from our personal, however on the time it was simply thought-about a fuzzy patch of sky. And Leavitt, as she turned her consideration to the small Magellanic cloud, as she studied variable stars that she discovered there, she, she made an extremely necessary simplifying assumption. She stated, I’ll deal with this as a person celestial object, the small Magellanic cloud, and so subsequently any variable stars I discover there will probably be equal distant to us from Earth, proper? So, If she finds a vibrant star there and a dim star, each inside the small Magellanic in a cloud, they’re touring an equal quantity of distance to one another to us, and subsequently, equally dimmed by that distance. So meaning she is aware of that relationship inside the cloud is true. That vibrant star is actually brighter than the dim star subsequent to it and so, because it translated onto glass, she would know that that relationship held true there. That meant she might flip to her glass plates and research variable stars within the small Magellanic cloud and see what she seen. As she began to trace these stars of their brightening and dimming cycles, she seen that the brighter stars appeared to take longer to finish their pulsation interval, because it traveled by means of that curve of dim to mild and again to dim once more.
And it took her a number of years to observe up on this line of considering and ensure that, certainly, it was true that the brighter the star, the longer it took to pulse. And Leavitt in 1912 printed a paper that graphed this relationship and the smoothness of the logarithmic curve of that graph was so clean and so pronounced that it was, certainly, a direct relationship.
And in, the truth is, it was regulation. It is now often called the Leavitt Regulation, the period-luminosity relation, that establishes that the brighter a variable star is, the longer it takes to pulse. And astronomers instantly acknowledged the importance of this discovering. So astronomers might merely observe a variable star pulsing, and based mostly on that remark, decide how vibrant it ought to be.
And if it was not as vibrant appropriately, they might calculate the quantity of distance inflicting that mild to dim.
Carol Sutton Lewis: So, Anna, for these of us listening who’re, like me, not fairly as properly versed within the area of astronomy, in only a sentence or two, are you able to please summarize for us why Leavitt’s Regulation modified our understanding of the cosmos?
Anna Von Mertens: Positive. Leavitt supplied an astronomical software that allowed. astronomers to easily observe the pulsation interval of a variable star. And from that, decide how far-off it’s from us. And so this present of having the ability to see one thing fairly clearly, simply the altering fluctuation of a star, and having the ability to calculate astronomical distance, opened up a complete new area of analysis.
Carol Sutton Lewis: Extra after the break.
Carol Sutton Lewis: So Henrietta Swan Leavitt, in spite of everything of this painstaking detailed work, decided a system to assist us measure the distances to pulsating stars, often known as Cepheid variable stars. How is that this groundbreaking discovery then used?
Anna Von Mertens: So as soon as this software was established that astronomers might merely observe the altering brightness of a Cepheid variable star and based mostly on these observations calculate its distance to us. This was most importantly put to make use of with Edwin Hubble was learning spiral nebulae. And maybe essentially the most well-known astronomical glass plate {photograph} within the historical past of astronomy is a plate taken in 1923, the place Hubble photographed the Andromeda Nebula, because it was referred to as on the time, and he seen three new lights. And he recognized these as Nova, new star.
However the subsequent night time he went again and seen that a type of Nova, a type of new stars, it modified in brightness. And he realized, aha, that may be a Cepheid variable star. That is one among Leavitt’s Cepheid variables. And so he crossed out N, Nova for brand spanking new star, and wrote V A R exclamation level.
And I wish to level out that exclamation factors do not present up in scientific knowledge fairly often, however there was good motive for it. Is that Hubble knew simply based mostly on that one single star, he might observe its altering brightness over time. And as soon as he established its pulsation interval, he might calculate its distance to us.
And so with one single star, he might present that Andromeda was so far-off from us, it needed to be exterior the scope of the Milky Approach galaxy, and was a galaxy in its personal proper. And now, take into consideration that. Assume that with one Cepheid variable, he might make this willpower. Now, if we return to the truth that Leavitt found 2,400 variable stars in her lifetime, after which inside that discovery made this necessary singular discovery that Cepheid variable star, the brighter it’s, the longer it takes to pulse. Hubble’s discovery was not potential with out Leavitt’s work. It’s Leavitt’s work that started this understanding of our three-dimensional universe.
Carol Sutton Lewis: So you’ve got simply introduced up the two,400 variable stars that by means of extremely meticulous, detailed work Leavitt found throughout her lifetime. And so this brings me again to the eye to element theme that runs by means of her work and thru your individual creative follow. And I need to flip to your artwork for a second.
You may have a collection referred to as the “Artifact Collection,” which was impressed by Leavitt’s work. Are you able to inform me about that, how you place it collectively?
Anna Von Mertens: I wished to follow, because it had been, the best way that Leavitt studied these glass plates. So I turned and, these glass plates, tried to use my very own consideration to them. And one explicit plate caught my curiosity as a result of on the edges of the plate, there was this very pronounced warping.
In order the starlight traveled by means of the telescope’s lens, it warped on the edges of the plate. Now, this was a phenomenon that Leavitt knew properly, and she or he wanted to navigate as she tried to tug set knowledge from these surfaces. However I used to be fairly enamored of those artifacts, of the best way that the starlight was warped, as a result of it virtually appeared to form of connect wings to those stars, as in the event that they had been form of moths and dragonflies and birds virtually retreating.
And the specificity of these objects caught my consideration, and jogged my memory of how Leavitt constructed her discovery, that she wanted to construct it star by star by star. And so I made a decision to understand that specificity by magnifying sections of the plate and drawing these explicit artifacts throughout the floor.
And what I used to be stunned is how simply my consideration was held by their, their magnificence, their transparencies, their depth, their peculiarities. And It jogged my memory how Leavitt, simply how evidently dedicated and engaged Leavitt was in her personal work. And so I’ve talked about that a part of what drew me to Leavitt’s story is that she had this profound discovery that launched trendy cosmology, however as a result of she herself didn’t dwell to see the influence of that discovery, I wished to know, properly, was she glad in her personal work?
And studying her scientific papers, studying her letters, and these glass plates myself, I might see how transfixed and engaged and delighted she was by this devoted work.
Carol Sutton Lewis: Anna, your enthusiasm and admiration for Leavitt’s work is splendidly clear. However you simply talked about that Leavitt did not dwell lengthy sufficient to see the influence of her work. So, are you able to inform me concerning the finish of her profession? What occurred after her groundbreaking discovery?
Anna Von Mertens: So, Leavitt spent her life learning variable stars on these glass plates at Harvard and introduced her discovery to the world, Leavitt’s Regulation, and astronomers form of instantly understood its significance and form of discovery tumbled forth from there. However, Leavitt sadly died in 1921, and, if you consider that well-known glass plate {photograph} that, Hubble took, it was in 1923. So solely two years after Leavitt died, Hubble discovered a Cepheid variable within the Andromeda galaxy and proved it was, certainly, a galaxy. And from there, proper, that, that Hubble’s work continued, that every time Hubble recognized a Cepheid variable star in a spiral nebula, he might calculate the quantity of distance to it and show that. How far-off it was and culminating on the finish of the Twenties along with his 1929 paper displaying that not solely had been there galaxies throughout us, however he proved within the redshift of their mild, that the farther a galaxy was away from us, the quicker it was receding. So, our universe was increasing.
So that you suppose inside only a decade, there may be this profound shift in our consciousness of going from, proper? Within the night time sky, uncertain of any sense of depth to them to understanding the form and scope of our Milky Approach and galaxies exterior our personal. So, I wished to have a good time this girl, who actually based trendy cosmology, however then additionally have a good time the life that she lived inside it.
Carol Sutton Lewis: Earlier, you talked about that Leavitt was one of many many ladies working at Harvard, and so they had their very own constructing to do that work. And but, despite the fact that that they had jobs within the area, astronomical work was nonetheless very a lot divided by gender. Ladies might solely catalog and analyze the information whereas the boys collected it. Are you able to speak somewhat bit extra concerning the influence that girls typically had on astronomy at the moment?
Anna Von Mertens: You are proper in that uh, girls weren’t allowed to make the pictures or observe at night time by means of the attention of the telescope. They labored by day analyzing the glass plates. What’s fascinating there may be there was form of a hierarchy given considering that observations straight made by means of the telescope was the place the science was. The science was really on, on the plates. That’s the place the information was and that is the place the discoveries had been latent. And so the ladies Leavitt and her colleagues, now often called the “Harvard Computer systems,” got entry, this primary entry level to the information. And sure, it was, there was just one job description for the ladies on the time, they had been referred to as computer systems and there was just one pay charge and no form of probability of ascending up a ladder on a profession, however given entry to this world, it’s evident how dedicated and devoted Leavitt and her colleagues had been to this work, and you understand, Leavitt spent her total grownup life there working on the Harvard School Observatory till her dying.
However alongside her had been girls who you understand, I’ve an inventory of of definitely, Annie Jim Cannon is properly often called her work targeted on the learning of stellar spectra, however she labored there for her lifetime. Mabel and Edith Gill had been sisters who labored there for many years. Ida Woods, one other Harvard laptop, labored there for 37 years.
So these girls had been devoted to the work and round that, an evident heat developed each for the work and for one another.
Carol Sutton Lewis: And evidently among the girls got recognition on the time, however why do you suppose our retelling of historical past usually overlooks the work of those Harvard computer systems?
Anna Von Mertens: that’s fascinating part that surfaced in my analysis for the guide, is that I feel many people, assumed that it was the sexism of Leavitt’s day that restricted her recognition. And searching at the moment, the ladies, the Harvard computer systems had been on the hub, on the very heart of worldwide astronomical analysis. So usually within the archive, there’s these letters written to the director of the observatory on the time of claiming, what are the newest updates? You recognize, are you able to inform me extra about this discovering? The place are we at on this analysis? So these girls and Leavitt particularly along with her variable star analysis, it was well-known inside the astronomical group, what she was as much as and, you understand, that their analysis relied on her work.
So what I discovered it’s that really it’s the retelling of historical past, of that historical past, that’s extra problematic. So usually the form of girls are form of dismissed as like, oh sure, it’s totally tedious meticulous work and it is acknowledged, however form of seen as perfunctory, or simply form of, you understand, the wanted work to get all the way down to the true analysis. And what I discovered is that, sure, like all science outcomes must be repeated. Science has a certain quantity of tedium to it, simply as Hubble wanted to measure circles of emulsion on his glass plates to make his personal findings. So the method is identical, however someway the work of the ladies is diminished as form of, being within the background the place actually they had been at the forefront of analysis, pushing the sphere of astronomy ahead.
Carol Sutton Lewis: That appears like a fantastic place for us to finish. However earlier than we do, do you may have any remaining phrases on how we must always all keep in mind Leavitt and this thrilling time in astronomical historical past?
Anna Von Mertens: So definitely celebrating her discovery and her legacy is a gigantic a part of this guide of actually seeing the science and seeing the influence that her discovery had on all future discoveries. However returning to that form of elemental unit of measuring a star’s brightness and star by star constructing a discovering, that on consideration was, was actually useful for me as a reminder that we are able to apply that talent to no matter endeavor we’re enterprise, whether or not it is a creative follow or a scientific one. So, the best way that I might see Leavitt’s engagement with this “work,” see this dedication, this dedication, even she writes the phrases “pleasure” and delight, recognizing how consideration builds and supplies a richness to the world round us and what’s accessible to see, that that was such a present, as a part of her legacy as properly.
Carol Sutton Lewis: So superbly stated. Anna, thanks a lot for penning this guide and for becoming a member of us at present.
Anna Von Mertens: Oh, thanks a lot for having me. And sure, thanks for serving to inform Leavitt’s story.
Carol Sutton Lewis: This has been “Misplaced Ladies of Science.” I am your host, Carol Sutton Lewis. This episode was produced by Sophie McNulty. Our thanks go to Anna Von Mertens for taking the time to speak with us. Hansdale Hsu was our sound engineer, Lexi Atiya was our truth checker, Lizzie Younan composes all of our music, and Lily Whear designed our artwork.
Because of Jeff DelViscio at our publishing associate, “Scientific American.” Thanks additionally to govt producers Katie Hafner and Amy Scharf, senior managing producer Deborah Unger, and program supervisor Eowyn Burtner. “Misplaced Ladies of Science” was funded partially by the Alfred P. Sloan Basis and the Anne Wojcicki Basis. We’re distributed by PRX. Thanks for listening, and do subscribe to “Misplaced Ladies of Science” at lostwomenofscience.org so you will by no means miss an episode.
Host
Carol Sutton Lewis
Producer
Sophie McNulty
Visitor
Anna Von Mertens
Anna is a visible artist and researcher who has exhibited broadly, together with in Boston, San Francisco, and Oslo. She was the recipient of an Alfred P. Sloan Basis Public Understanding of Science and Expertise guide grant to help the publication of Consideration Is Discovery. She lives and works in Peterborough, New Hampshire.
Additional Studying
“Overview: How a Group of Ladies Launched Fashionable Cosmology,” by Lucy Tu, in Scientific American; September 2024
