Science Friday - The Women Astronomers Who Captured the Stars

Episode Date: December 11, 2023

In the late 19th century, astronomy was a growing field. At the time, Edward Pickering, the director of the Harvard College Observatory, was working to create a classification system for stars by capturing the light from these distant celestial objects onto photographic glass plates. A team of women assistants and astronomers meticulously maintained and analyzed these delicate negatives. In her new book, The Glass Universe: How the Ladies of the Harvard Observatory Took the Measure of the Stars, Dava Sobel shares the stories of these “human computers” and how their work helped to advance the field of astronomy and the role of women in science.This team of astronomers included Williamina Fleming, who was once Pickering’s maid but eventually became a supervisor to the group and went on to identify hundreds of variable stars. And Henrietta Swan Leavitt’s observations about the luminosity of stars would shape later ideas about the expanding universe.To stay updated on all things science, sign up for Science Friday’s newsletters. The transcript for this segment is available on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

It's an important day in the history of astronomy, the birth date of a pioneering scientist who helped us classify the stars. At the beginning of the story, almost nothing was known about what stars were made of, how they created their heat and light, and by the end, just about everything was known. It's Monday, December 11th, the birthday of Annie Jump Cannon, who was born 160 years ago today. It's also Science Friday. I'm John Dankowski. of the 19th and the start of the 20th century, Cannon played a key role in cataloging and understanding the stars in the sky. Today, she's honored with the Annie Jump Cannon Award, which is given for outstanding research and promise for future research by a postdoctoral woman researcher. Back in 2016,

we got a history lesson about Canon and her colleagues. Let's give a listen. Here's Iroflato. When you look up at the sky at night, you've probably noticed that each star has its own brightness. You might even know that measuring that light can tell you how far away it is, the composition of that star, and even reveal clues about the expansion of the universe. But you may not know that our understanding of how to classify stars came from the work of a group of female astronomers, women who worked at the Harvard College Observatory 100 years ago. My next guest is the author of a new book that recounts the stories and discoveries of those scientists. David Sobel is author of the Glass Universe, how the ladies of the Harvard Observatory took the measures of the stars.

And she joins me in our CUNY Studios. Welcome back. Always good to see you. Thank you. Fun to be here with you. And let me let our listeners know that we have an excerpt from the book on our website at ScienceFriday.com slash universe.

Now, Dave, you've written women in astronomy before, Galileo's daughter. How did you come across this group of female astronomers? I first learned about them from astronomer Wendy Friedman. I was interviewing her. It must have been more than 20 years ago. And she mentioned the name Henrietta Levitt, which I had never heard. And then when I went to look up more about Miss Levitt,

I discovered she was in a room full of women at Harvard, which was a big surprise. Yeah. One doesn't think of lots of women getting to do astronomy at Harvard. You know, we're hearing so many more stories. about women, scientists, engineers that we never heard of. I know.

It's their moment. It is their moment. When this group started out, they were working even before women had the right to vote. That's how long ago that was. 1870s, 1880s. It's really exciting stuff.

So what was it like to be a woman and amongst male scientists to be female scientists who was doing research? I think it was fine. They were very well treated. They got credit for their work all the time. They knew they were doing something unusual. that they'd been given a remarkable opportunity,

and they ran with it. And what was their main job? What were they supposed to be doing? The main job in this book is the analysis of photographs on glass plates. So this was a new thing in astronomy to be able to take long exposure photographs and discover things that couldn't be seen even through the most powerful telescopes. So they were actually making discoveries, and they were trying to figure out how much they could learn from starlight about the content of the stars, their evolutionary history, their distances. At the beginning of the story, almost nothing was known about what stars were made of, how they created their heat and light.

and by the end, just about everything was known. And looking at the photographs, basically they slaved over these glass plates. Describe what they were doing. Yes, well, they're large plates. Some of them are 8 by 10, some are 11 by 17, and there are thousands of stars on them. Thousands.

Appearing as black little dots. Little black dots. Or for some pictures, the light got passed through a prism, and then instead of a dot, there'd be a little strip, A little smear of a strip for each star with shades of black, white, and gray, and dark lines. And from those patterns, they created a classification system for the stars that is still in use. So they had to decide how bright the star was, how far away it was it might be?

When they were looking at the spectra, they were really looking at the pattern of the lines and trying to figure out which patterns made a logical category. And people needed those different categories to be able to get a taxonomy of the stars. So they were basically cataloging all of these stars? Yes, yes, cataloging, categorizing. Then there were also studies about brightness and constitution. People want to know what elements were in the stars. And towards the end of the story,

when the women in the observatory were not just working there, but doing graduate research, graduate level research, the great abundance of hydrogen in the stars came to light for the first time. Edward Pickering, as you talk about, was the director of the observatory and the first person to start hiring the women. Why did he hire women? He found some women there when he got there

because the resident astronomers, wives, daughters, sisters had already been put to work. So there was a precedent. But then in his time, women began to be hired from outside. Women who didn't have any particular background in astronomy, but they were good at math and they could do calculations and they were welcomed. They also cost less to hire an evergreen theme.

Yeah, yeah. In fact, one of the first members of the team, Willamina Fleming, started out as Pickering's made. Yes, yes. Yeah, she was in desperate straits because she'd been married. Now she was pregnant, and her husband had disappeared on her. So she took the job as a maid. But he noticed how bright she was and moved her over to the observatory and taught her how to do the work there.

Now, as you point out, the hiring of the women was important, but the funders themselves were also women. Yes. Yeah. The big project for Classifying the Stars was completely funded by a very wealthy New Yorker named Anna Palmer Draper. And she had worked with her husband on a project that, they were hoping to devote their lives to. And then he died suddenly at age 45. And she, out of love for him to create a memorial, she gave the money to Harvard to carry on his work. And the money she gave was beyond their entire annual operating budget every year. Wow. Cecilia Payne Gapashkin, is that her name?

Yes. She was one of the late members of the team, and we have a clip from an interview recorded in 1968 by the famous Owen Gingrich, who was a great historian of science, from the Niels Bohr Library and Archives at the American Institute of Physics. And here she describes leaving Cambridge for Radcliffe College, which was the female annex of Harvard. The whole thing was pretty intoxicating, and also being free for the first time to do astronomy, just as much as I want. when I never had been before was intoxicated because even though I had done these little bits of research at Cambridge, lights had to go out as 11th and the wreck of building where I worked didn't even mind if I was out all night working. For a bit I almost worked night and day without stopping. It was marvelous. Wow.

So she earned the first PhD in astronomy at Harvard. Harvard. And that came about as a result of all the earlier women because another heiress gave money for fellowships for young women to come and work at the observatory for a year and then go on for full-time employment somewhere else. And so when the new director who replaced Pickering after his death, Harlow Shapley started a graduate education program in astronomy, the only fellowship money he had was these fellowships for women. So all the early graduate students were women. And so these women who might have remained maids or, you know, when the former jobs were given a way out, a way up. A way up. But by that time, there were many more women

coming in who'd had a college education and had experience on the telescope, even by 1896, when Annie Jump Cannon came to the observatory. she was allowed to make her own observations. You know, it struck me that the title, Glass Universe, is also the Glass Sealing. Indeed. Was that on? It was very intentional, yes.

Wow, that's great. But the Glass Universe is the plate collection. Yeah. Very nice play on words there. Talking with Davis Obel, who is author of the Glass Universe, how the Ladies of the Harvard Observatory took the measure of the stars.

And how important was their work to what we're seeing today? in astronomy? Well, the classification system is still used. It led to the understanding that the different categories really signified different temperatures. At the beginning, it wasn't known what they signified. They just looked different. Now we know they're different stellar temperatures because stars have different lifestyles. And they also help show the life stage of the star. Another study, which was not really related to the classification, but the work done by Henrietta Levitt, which Wendy Friedman first mentioned, has to do with being able to tell relative distances in space. And that first led to an understanding of how far away from us the satellite galaxies of the Milky Way that you can see from the Southern Hemisphere.

hemisphere. She was looking at pictures of those, and her discovery helped establish how far they were, and then how big the Milky Way was. And then Edwin Hubble used her discovery to show that the Milky Way was only one galaxy among many, and later used it again to show that the universe was expanding. So it was pretty important. How many Nobel Prizes were these women? Unfortunately, Somebody wanted to give Ms. Leavitt the Nobel Prize, but she'd already died. And you can't win it posthumously, so she missed out. You know, we talked to Margaret Lee Shetterly, who wrote hidden figures about the African-American human computers at NASA. Do you think there are, and these are also these women who've spoken of as computers, too, right?

Yes, yes. These were the great granddaughters of the Harvard ladies. And do you think that there are other teams of human computers doing other things that we haven't? discovered it perhaps coming out now? I don't know. After the Rocket Girls and the Langley women, I don't, I think we've tapped all the computers, but if I'm wrong, I'll be happy to learn more. And Dave Obole is author of the Glass Universe,

how the ladies of the Harvard Observatory took the measures of the stars. And you can read an excerpt of her book at ScienceFriety.com slash universe. Let's go to the phone. Let's go to Bonnie in Northern Virginia. Hi, Bonnie. Hi, Ira. Hi there. So I'm an Earth, well, I taught Earth science for about 14 years, and now I'm teaching middle school science.

And when I was teaching Earth science and showing the kids how to do the HR diagram and all that, I always would, you know, let them know about Annie Cannon and how she had a big role to play in that, but she did not get much credit. And so I'm just wondering now with this research that's showing, you know, how much women were actually involved in this stuff, you know, when are we going to start getting, you know, being able to give them credits? Like, when are the textbooks going to catch up? And when are people going to start knowing Annie Cannon and some of these other ladies

by name the way that we know Niels Bohr and other scientists who were all men? Well, maybe now. But just to make you happy, I hope it'll make you happy, she really did get credit in her own lifetime. And she was awarded the Draper Medal from the National Academy of Sciences, which was a huge honor. So during their lifetimes, the women definitely felt appreciated, and all their discoveries were credited to them in their publications. Thank you for calling, Bonnie. Good luck with your kids. Talking with author Davis Obel, who's author of The Glass Universe,

how the ladies of the Harvard Observatory took the measure of the stars. She brought up an interesting point about women's scientists and getting the recognition that they deserve. Is that an issue, do you find? You've spoken to a lot of women's scientists. Do they still feel it's still an issue with them? Well, they still feel it's a problem to get the high-level position. I don't think getting recognition for work done is a problem.

But I think generally now there is so much anti-science bias that the more we can tell true stories about science, we'd better get them out there. It's true. You know, I was asked to put a panel together of women's scientists. I went to four physicists I know, women scientists. I asked each one of them. Would you want to sit, please sit on a panel of women scientists? And all four of them said, no. We don't want to be known anymore as women scientists.

One of the women at Harvard today was given a chance to be considered for the Annie Jump Cannon Prize, which is still awarded every year. And she refused because she didn't want any prize that was just for a woman. So there's that issue, too. complex. Yeah, they want to be known as just women who do science like men. Like men who do science that want to be categorized that way. Right. Well, how did the women get along together? I mean, here you have all these strangers, right? Yeah, no, they got along very well. They had to work in pairs because when one was looking at a plate, she would have to say aloud

what she was seeing that. It would waste too much time to be looking up and back. So they had teams, and then they all pitched in on big projects, especially the publications. Those publications have page upon page of numbers and columns, and everything had to be carefully proofread, so groups worked together on that. And then they all socialized together. Is that right? Saturday night, they get together and play games and make music. It was a very collegial group. It was a close-knit organization. Yes, and the observatory was a sense of not only for the people who work there, but visiting scientists from other observatories and from Europe. Some people came from Europe and spent months or years there because of the plate collection.

And then they finally combined the two observatory, Harvard and Smithsonian. And Smithsonian, yes. And today it's the Harvard-Smithsonian Center for Astrophysics. Great place. Yeah. Great place. You visited often? Often. It was my second home for a few years and happily said. We can see from the book a lot of work, a lot of research went into this book. But I enjoy that.

People who complain, they slaved and dusty archives. I don't buy. Nobody makes you do it. It's really fun. Well, we can tell you had fun and enjoyed it from how well the book turned out. Thank you. Thank you for writing. Thank you, so much.

The Vice, Author of the Glass Universe, how the ladies of the Harvard Observatory took the measures of the stars. She's with me in our CUNY studios, and you can read an excerpt from the book at her website at ScienceFriady.com. slash universe. That's all the time we have. Happy birthday, Annie Jump Cannon. We'll be thinking of you when we look up at the stars tonight. And speaking of the stars, coming up on our next episode, we'll sit down with astronaut Mike Massimino. I hope you can join us. I'm John Dankoski. We'll talk to you soon.