Virginia Trimble (PhD '68), Pioneer of Dark Matter Astrophysics and Historian of Astronomy

The Caltech faculty decision to admit Virginia Trimble as a graduate student in astronomy was "exceptional," as she calls it. The de facto admission policy at the time was that the program was not available to women, but Trimble was too brilliant, too full of promise, and too well-credentialed not to gain admission. Her subsequent career, as one of the world's preeminent scientists working in dark matter research and the structure and evolution of stars and galaxies, supports a decision that never should have been a question in the first place. With over 600 publications, legendary conference talks, and a distinguished record as a historian of astronomy, Trimble is both a giant of the field and a trailblazer for the long overdue inclusion of women in the ranks of elite astronomy.

In the discussion below, Trimble speaks frankly of the gender politics of the time, and the strategies she used to navigate in an environment where it was never just about the science. Trimble insists that she had fun and she always felt empowered, not despite the power imbalances but because she learned to use them in her favor. As Trimble jokes, she was a happy participant in all kinds of interactions that "would get everyone fired today." Whether despite the culture or because of it, the result was a sustained investigation of the Crab Nebula which remains a classic in the field, a postdoctoral appointment at the University of Cambridge during the dying days of the Steady State theory of the universe, and a decorated research career that continues to the present day.

DAVID ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It is Monday, February 19, 2024. It is my great privilege to be here with Professor Virginia L. Trimble. Virginia, wonderful to be with you. Thank you so much for joining me.

VIRGINIA TRIMBLE: Thanks for asking!

ZIERLER: To start, would you please tell me your title and institutional affiliation?

TRIMBLE: I am Professor of Physics and Astronomy—in fact Professor 8 in the University of California system—at University of California, Irvine.

ZIERLER: Virginia, how long have you been at University of California, Irvine?

TRIMBLE: That's a complicated question, because I arrived in Fall of 1971, but for 30 years I spent half of each year at the University of Maryland because I was tenured in California and my husband Joe Weber was tenured in Maryland. From 1973 until his death in 2000, we spent January to June in California and July to December in Maryland.

ZIERLER: The duality of having appointments at both universities, having that dual perspective, what was the value of that for your research and all of the things you've worked on?

TRIMBLE: Research, that's going to take a long one, but it was useful in giving me the perspective on how different universities could organize their teaching, their committees, their enforcement of academic honesty on their students, and umpteen-godzillion other things, some of which were the same both places and many of which were different.

ZIERLER: You're still active in research and teaching these days. What is interesting to you in physics and astronomy and astrophysics?

TRIMBLE: Let me back up and answer the second half of your previous question. When I arrived at UC Irvine in the Fall of 1971, I was not only the first woman on the faculty; I was the first astronomer, and I was the only woman and the only astronomer for 15 years each. Going to Maryland, at least there were other astronomers, and in fact there were a few other women astronomers, like the wonderful, wonderful Jill Knapp who was just finishing her graduate work. She is now at Princeton. She pioneered teaching in prisons.

ZIERLER: Given that you're still active in research and writing, what is interesting to you in astronomy and astrophysics, cosmology, all the things that you've worked on?

TRIMBLE: Let me give you a very broad answer—the structure and evolution of stars, galaxies, and the universe, and of the communities of scientists who study them. That second half is history of science and financial metrics.

ZIERLER: I'd love to know, as a fellow historian of science, what prompted you to get interested in history of science?

TRIMBLE: I got old.

ZIERLER: [laughs]

TRIMBLE: I'm—semi-seriously. From time to time, I was asked to do something, either introductory remarks at a conference or sometimes concluding remarks, and I would realize that in the course of the conference, or on the program of the conference, nobody had said anything about how we got to the position to have this conference. So I started putting in, into introductory remarks, and sometimes into concluding remarks, a bit about the history of the subject of the conference. I started writing, and people asked me to write more. My publication list passed a thousand last year. [laughs]

ZIERLER: Amazing.

TRIMBLE: A lot of them are book reviews, but they're almost all sole author.

ZIERLER: [laughs] A fun question—if you could go back in time, to the first time that you thought about dark matter—here we are in 2024—are you surprised at how little progress or how much progress has been made in dark matter research?

TRIMBLE: Neither of the above. Look, when you're 80 years old, it takes a lot to surprise you!

ZIERLER: [laughs]

TRIMBLE: Seriously. I wrote one of the first all-over reviews on dark matter for Annual Reviews in 1983, or somewhere in the mid 1980s, and what I thought then is what I still think—that the phrase is a wonderful shorthand for an enormous range of observations that indicate somehow gravity gets stronger as you go to larger scales.

ZIERLER: Do you feel like we're any closer today than in 1983?

TRIMBLE: We know some more things that are not the right answer or probably not the right answer, because people have looked hard for them and not found them, or done observations or experiments to test what would happen if a particular kind of dark matter was there in large quantities. So, if ruling out things in progress—and I think in science we have to count ruling out things as progress, and sometimes in politics as well—but if ruling out things is progress, there has been progress. Do I think people are going to find a magic particle that is the answer? I don't know!

ZIERLER: We'll have to wait and see.

TRIMBLE: I am in some way a protégé of Richard Feynman; it doesn't bother me.

ZIERLER: [laughs] That's right.

TRIMBLE: He always said, "If you have an unanswered question and it bothers you, you shouldn't be a physicist."

The Path to Astronomy

ZIERLER: That's a great segue. I want our conversation today to be a complement to the oral history that you've already done with David DeVorkin, and of course what brings us together is Caltech, so I want to focus our conversation on the stories about how you got to Caltech and your experiences at Caltech. Let's start first—as an undergraduate, I know you were very wide-ranging in your interests. When did you begin to focus on astronomy?

TRIMBLE: Never. [laughs] In fairness, in the good old days, when I applied to UCLA to be an undergraduate there, it was the only place I applied, and Caltech was the only place I applied for graduate school. When you applied to UCLA in those days, you had to declare a major. I wanted to be an Egyptologist, and I almost made it by marrying into the profession, but in the end I didn't. But you had to declare a major. They didn't offer archeology at UCLA as an undergraduate major. They sent a catalog, and the first thing listed was art. That was clearly not a good choice, overwhelmingly. But my father looked at the catalog and my father declared, "You've always been interested in astronomy." What he had in mind was that when I was a kid I liked being taken to Griffith Observatory.

There were three astronomy majors. There was pure astronomy, there was astronomy math, and astronomy physics. I applied in astronomy math, and was accepted at UCLA, with a Thomas H. Watson Memorial Scholarship. I didn't cost my folks very much to go to college. I started out in astronomy math. That moved over to engineering, because it was really orbits, and orbits became satellites rather than meteors, comets, and asteroids. I stayed behind in liberal arts in astronomy physics. The official advisor was George Ogden Abell, of blessed memory. I approached what would have been the beginning of my senior year—it turned out I would in fact finish in three and a half years instead of four because of good use of summer school—Uncle George said I should apply to Caltech, and he put me in for a Woodrow Wilson Scholarship, fellowship. I got the fellowship and I was admitted to Caltech, so I went.

I did the astronomy physics major with a lot of other courses, because in those days students were allowed to take many more courses than they are now. The norm was six every year plus a unit left over to sing with the UCLA A Capella Choir under Roger Wagner. I got to take linguistics. I got to take a year of ancient Egyptian hieroglyphs with the wonderful Miriam Lichtheim. I got to have a year of ancient Egyptian art and architecture with the remarkable Alexander Badawy. And paleontology and other fun things.

ZIERLER: What were George's connections at Caltech? Did he have formal collaborations here?

TRIMBLE: George was a Caltech alum. I think he was maybe the second person to do a PhD in Astronomy there after Greenstein established the program. I think the first was Helmut Abt, who still lives and flourishes, and I exchange emails with him occasionally. I think Uncle George was the second Caltech PhD in Astronomy, and then the third was Chip Arp. Then they finally got away from the A's.

An Exceptional Admission to Caltech

ZIERLER: Did you know at the time that Caltech had almost no women students, graduate and certainly not undergraduate?

TRIMBLE: Yes and no. It was only somewhat afterwards that I actually saw the catalog that said, "Women are admitted only under exceptional circumstances." I wrote my essay to explain my exceptional circumstance, which was that I had the Woodrow Wilson Fellowship and it required me to change institutions. That meant I had to leave UCLA. Caltech was the only other place in Southern California that had astronomy in those days. I was not prepared to leave home. I lived with my parents through my first year of graduate school. I wasn't prepared to leave home and I wasn't prepared to leave Hollywood, because there were some money-making opportunities there.

ZIERLER: What were those opportunities?

Hollywood Interlude

TRIMBLE: The one that is now I think almost not invisible was being with Twilight Zone for a year.

ZIERLER: What did that entail?

TRIMBLE: You're not old enough to remember Rod Serling and Twilight Zone, are you?

ZIERLER: I've heard of it, of course.

TRIMBLE: Their last year of new programs, they wanted to get the ratings up so they could sell the residuals for more. It was the publicity agency, Rogers & Cowan that had the idea, to get an elegant call girl and dress her in a space suit. The space suit disappeared. But because I had been in LIFE magazine the previous year, somebody at Rogers & Cowan identified me as a likely Miss Twilight Zone. I interviewed with the publicity agency and with Rod Serling as a possible person to tour for them to all the Nielsen cities—Houston, Dallas, Chicago, Cincinnati; I know them all in order—to tour all the Nielsen cities to advertise Twilight Zone, in newspaper interviews and morning wake-up programs, radio, television, and dot-dot-dot. I did a couple weeks of that and it brought in enough money to pay my registration and books and things for the last two years of my time at UCLA.

ZIERLER: How long did you stay with The Twilight Zone?

TRIMBLE: I was Miss Twilight Zone for the year. I toured for two weeks. Then the next year they didn't do new programs anymore. The official shtick was I was supposed to read the scripts for scientific accuracy. They sent me a whole pile. I read them, and I sent some suggestions. I believe my suggestions were taken twice out of umpteen godzillion. But that's a lot for a kid.

ZIERLER: [laughs] What were the circumstances of winning the Woodrow Wilson Fellowship? Obviously this was available to women.

TRIMBLE: I only learned later that first-year NSFs were not, so I didn't get an NSF until my third year of graduate school. The Woodrow Wilson was in those days designed primarily for the liberal arts, but I was not in fact the only Caltech astronomy student to have been offered one. I took it because somebody else—it may have been Jeff Scargle—somebody else was offered one and took an NSF because it paid more. I took the Woodrow Wilson because it was what I was offered. I was interviewed by them, and what made them think I was an appropriate person in spite of being an astronomy physics major was that I could read and write ancient Egyptian hieroglyphics.

ZIERLER: That was too irresistible for them.

TRIMBLE: There's no such thing as useless knowledge, David.

ZIERLER: There you go. I like that.

TRIMBLE: Smith College interviewed me for my first job out of graduate school because they liked that, but what really persuaded President Mendenhall that I was the right person for them—I could sing second sister in the faculty production of Pirates of Penzance.

ZIERLER: [laughs] That works!

TRIMBLE: It works. I'm teaching Physics of Music this quarter.

ZIERLER: Really!

TRIMBLE: As well as General Relativity, yeah.

ZIERLER: Oh, that's great. Virginia, what year did you arrive at Caltech?

TRIMBLE: 1964. I left in Spring of 1968. I went from high school graduation to a PhD in seven years and three months.

ZIERLER: Wow. What was it like when you arrived on campus? What do you remember?

TRIMBLE: They decided I should come for an interview, because they had written that my credentials clearly made me eligible, but they thought I might be happier elsewhere. The first thing I consciously remember is going up the stairs in Robinson Hall and looking around to find a room number I was supposed to report to. The second thing I remember—I talked to a number of faculty members. Greenstein wasn't there that day, and I talked to him on the phone later. But I noticed that Guido Münch was wearing a wedding ring in May of 1968. When I arrived as a student in September, the wedding ring was gone.

ZIERLER: And then what happened?

TRIMBLE: What do you think happened? [laughs]

ZIERLER: [laughs]

TRIMBLE: Somebody told me I should tell all my stories because I know all the skeletons in the closet. There are contexts where I am the skeleton in the closet. Two things happened. I did my PhD with Guido on the Crab Nebula, and we became lovers. We were almost getting married, and he decided he couldn't afford me and dumped me for a woman who was self-supporting.

ZIERLER: How did you feel about that?

TRIMBLE: How did I feel?

ZIERLER: Yeah!

TRIMBLE: Miserable!

ZIERLER: But you recovered?

TRIMBLE: Oh, yes! I fairly recently wrote the National Academy of Sciences memoir about him.

ZIERLER: What did you say?

TRIMBLE: I knew him both as a human being and as a scientist, and that's a perspective you don't get all that often.

The Beautiful Wrongness of Steady State Cosmology

ZIERLER: That's right. Virginia, what were the big topics in astronomy when you joined at Caltech? What were people working on?

TRIMBLE: A lot of them were still working on stars. Cosmology and relativity had not been part of the landscape there. H.P. Robertson, the great relativist, had died a couple years before, and they had not replaced him. When they replaced him, it was in 1966, and they hired Kip Thorne from Princeton. So, there was not relativity. There was not really cosmology. It was not taken seriously by the Astronomy faculty. The students wanted cosmology, and so Jim Gunn, who is also now Emeritus at Princeton, organized a student seminar where we met weekly and each of us took a topic and we taught each other cosmology. Maybe mostly Jim Gunn taught the rest of us, in fact. I picked Big Bang versus Steady State, which was also then settled. It wasn't really an open issue. But I've always loved Steady State cosmology; it's just wrong. It's beautiful; it's just wrong.

Most people worked on stars and galaxies, where stars and galaxies included interstellar material, and trying to understand the distribution of stuff in the Milky Way. The spiral structure of the Milky Way was only just then being established by the radio astronomers, so one looked for it also in optical data. Münch himself was interested in stuff above and below the plane of Milky Way in spiral structure, and also as the Space Age got started, in the atmospheres and other structures of Mars and Jupiter and so forth. I never dabbled in planetary science. Most of his students did stars and galaxies, but he himself became quite interested in the atmosphere of Mars, showing that it was much thinner than people had thought before, and in the structure of the atmospheres of Jupiter and Saturn, in the data from Mariner 9. Greenstein continued to love white dwarfs. That was my second-year research project. It was thought to be impossible. If you have an impossible task, you give it to a graduate student! And if it's really impossible, you give it to a female graduate student. Consider the case of Jocelyn Bell at Cambridge.

Jesse Greenstein and White Dwarves

ZIERLER: What came of the white dwarf research?

TRIMBLE: Several papers. The first one was Greenstein and Trimble; the second one was Trimble and Greenstein. It turned out that what he wanted could be done, which was to measure the general relativistic redshift of the light coming from the surface of white dwarfs. Back in 1964 or 1965 when we started this, there were three white dwarfs whose mass was known—the companion of Sirius, the companion of Procyon, and the companion of 40 Eridani B. Their masses were 0.4, 0.6, and 1.2 solar masses. Now, with a factor of two uncertainly, what is the average mass of a white dwarf? Gravitational redshift was a way to try and establish that. The number that we ended up with is now regarded as slightly too large. The official number now is something like 0.55 solar masses. Our number was more like 0.65. So, the gravitational redshift was a little larger than people studying the atmospheres now think it should be. The reason for this is not understood, at least not by me.

ZIERLER: It's not necessarily that you made a mistake?

TRIMBLE: I suppose in some sense I must have, but it's not clear what mistake I made. The problem was to figure out what part of the line profile to focus on. The absolute core was not relevant because that is established way up in the upper atmosphere, where you have the most opacity. The extreme wings were wrong as well, because they're down in where pressure effects are important. If you look at an average white dwarf hydrogen line profile, it has a sharp core, it has wings, and it has a sort of plateau. I focused on the plateaus. Apparently there's some very small effect that makes the average white dwarf line profile very slightly redshifted when you look at the plateaus. It's got to be something like convection. It has got to be a gas-type effect. I don't know to this day exactly what it was. I also am not actually sure I was wrong [laughs]. The other measurements are also indirect, and they measure m over r squared, rather than m over r. Nevertheless, those papers at the time were very highly cited, and Greenstein talked about the results at the 3rd Texas Symposium in New York in January of 1967.

ZIERLER: You mentioned your appreciation for Steady State. Did you ever meet Fred Hoyle?

TRIMBLE: Of course! I did a two-year postdoc in Cambridge! He was officially my advisor! [laughs]

ZIERLER: Did he ever give up on Steady State, or he held onto that until the end?

TRIMBLE: Yes and no. [laughs] Look at the other two first. Hermann Bondi went on to become a major figure in politics of science in Britain and in Europe in general. He was the director of ESRO, The European Space Research Organisation. Tommy Gold also went on to other things like the surface of the Moon and quasars and what have you. Hoyle stuck largely to cosmology, though he also did things like trying to prove that the archeopteryx fossil was a forgery. He had three or four postdocs and young faculty with him in Cambridge who reinforced his self-confidence. One is still alive, Jayant Narlikar in India, so there is still one Steady State person alive, I think. And I hope that will remain true for a long time!

Maxwell said that science progressed one funeral at a time, because people who believed in something died out and that made room for a new idea. Narlikar was one of Hoyle's acolytes and he still supports some kind of Steady State, I think, as did Geoff Burbidge and others. Chip Arp, of course. But Hoyle was an absentee landlord. He only came to the Institute when his buddies were there to work on something with him, Willie Fowler and the Burbidges and so forth, so the intellectual leadership at the time I was there was provided by Martin Rees, who is now the Astronomer Royal and Lord Rees of Ludlow and all that.

ZIERLER: What was Hoyle's perspective on the cosmic microwave background?

TRIMBLE: Of course that came already quite late in his life, but he and some others tried to—well, they did a calculation, which was correct. It turns out the universe is about a quarter helium, and if you turn a quarter of the hydrogen into helium, you get a bunch of photons, and the energy density in those photons is the equivalent of about three Kelvin. You can't use it; it's in the wrong wavelength. They postulated an intergalactic population of long, thin, iron needles which would thermalize the radiation from fusing hydrogen to helium into a microwave background. It's not impossible. It begins to fail when you ask about deviations from the precise black-body spectrum and deviations from the precise isotropy of the microwave background. Eventually, it fails. But it only truly failed when Hoyle was really past being very interested in the universe, I think.

ZIERLER: Were there any Steady State believers at Caltech?

TRIMBLE: No. [laughs] Dear old Uncle Allan—Allan Sandage is quoted in Helge Kragh's History of Cosmology as saying, "Steady State was never taken very seriously in California."

ZIERLER: [laughs]

TRIMBLE: That's hysterically funny because by California he means Pasadena, because just 50 or 70 miles south is the University of California San Diego, and Margaret and Geoff Burbidge were there, and they took Steady State very seriously.

Palomar and Imaging the Crab Nebula

ZIERLER: Right. [laughs] Virginia, tell me about your time at Palomar Observatory. What did you work on there?

TRIMBLE: I was attempting to get images of the Crab Nebula in narrow wavelength bands that would focus on particular emission lines to do a study of the distribution of ionization and excitation energy in the Crab Nebula, using more data points than were available from existing spectra taken by first Rudolf Minkowski and then by Guido Münch. The way to do that was to isolate the line with a combination of particular Eastman Kodak emulsions of which there were like 25 in those days, and a particular filter that would cut off light both too long-wave and too short-wave to be in the particular line you wanted. This would have been something that might have been rather interesting done with a 200-inch, in a large image of the Crab Nebula, but 200-inch time was not available to graduate students. I did this with a 48-inch Schmidt. The images in the different lines looked very different, and I did some analysis of that—it's in my thesis—and it was sort of published in Astronomical Journal a couple years after I finished the PhD, and refereed by Rudolf Minkowski, who found a horrible mistake in the table and just kindly told me and didn't tell anybody else. He was a real gentleman.

Anyway, the goal was to find out the distribution of ionization and excitation energy, which is a moderately interesting problem now because the ionization unquestionably comes from continuum radiation that is powered by the synchrotron radiation from the electrons that are accelerating by the pulsar, whereas a lot of the excitation apparently is powered by collisional energy between the outer bits of the nebula and the surrounding interstellar material. But the data weren't good enough to do a very good job of this. And nobody else is now interested. [laughs] It's just one of those things.

ZIERLER: If I understand correctly, you were also a bit of a woman pioneer at Palomar. There really had not been women who worked at Palomar before.

TRIMBLE: I was number two to be assigned time in my own right. Margaret Burbidge had observed there, extensively, with time assigned officially to Geoff, her husband. The first woman ever assigned time in her own right at Palomar was Vera Rubin, and I was number two when I went in 1966. She went in 1965. When I went in 1966, I was the second woman ever assigned time there in my own right, in my own name.

ZIERLER: What was the state of the art in Crab Nebula research, and how did your research respond to those big questions?

TRIMBLE: There had been two PhD dissertations on the Crab before mine. The first one was a very extensive study of everything available at the time in 1957 by Lodewijk Woltjer. Then Bob Williams, who is now the retired head of Space Telescope Science Institute, did a thesis on plasma processes in the Crab Nebula. What happened was that Guido had two piles of plates, one taken in emission lines and one taken in the continuum. He divided his plates into those two piles and he gave the continuum plates to Jeff Scargle and the emission line plates to me. He said, "Go measure things." I think—well, I guess I know—that he thought the continuum plates were going to be more interesting. And with a little more—well, five years later, they probably would have been, because there's all kinds of motion that is centered around the pulsar. But the pulsar had not yet been discovered.

What might be interesting in the emission line plates was not obvious. But what I got out of that was a good measurement of the distance, a good measurement of the fact that the expansion had been accelerated over the age of the nebula, that the acceleration was the amount you would expect from the pressure from the relativistic particles and magnetic field inside that were making the continuum the synchrotron radiation, and a bit about the ionization and excitation. As this was going on, the first pulsars were discovered, and then one in the Crab Nebula that had in fact been imaged through radio earlier by Tony Hewish and Sam Okoye in Cambridge. Sam Okoye was an interesting guy, the first Nigerian astronomer, radio astronomer. It turned out to be a good year to work on the Crab Nebula. It got me invitations to go to conferences and be invited to give talks and get a job. It was a good year to be interested in the Crab Nebula.

ZIERLER: What was it like working at Palomar?

TRIMBLE: Cold! The Crab Nebula is up in November, December, January, which is not the best weather in California. I was rained out part of the time. There's a Chip Arp story that goes with that. When the telescope could be used at all, the first thing was it was cold. I hate being cold. The other thing is that the 48-inch Schmidt—now called the Oschin Telescope, I think—required in those days that you lift a plate holder into the focal plane and clamp it down at the back of the telescope, lifting it over your head. California in those days had a law that women could not have jobs that required them to lift more than 40 pounds. [laughs] The 48-inch plate holder weighed 50 pounds. I could just barely lift it. But the night assistant usually helped. I was violating the laws of the state of California when I observed there! [laughs] I was lifting something more than 40 pounds. I couldn't do it now, probably. I'm also not tall enough to reach the focal plane of the 48-inch!

There were lots of interesting things. My very first run, I hadn't understood the time schedule. You finally get to bed maybe at 5:00 or 5:30 a.m., maybe 6:00 a.m. after developing your plates and drying them out and all the rest, and I didn't realize that the first meal would be at 12:00. I was awakened by my thesis advisor calling the next morning to find out how it had gone, and I was grateful because otherwise I would have gotten no food! [laughs] The other thing—I require regular meals. I really do. It turned out just fine in the end. They arranged things so that people who were on a daytime schedule get a lunch at 12:00, the observers who observed the previous night get breakfast at 12:00, and then there's a general meal before sunset for everybody. Then for those who are on the night schedule there's midnight lunch, which in those days was fixed by the night assistants.

ZIERLER: Virginia, tell me about Guido. What was he like as a person?

TRIMBLE: It's Guido; it's a hard "G."

ZIERLER: Oh, Guido, okay.

TRIMBLE: Guido. [laughs] He was very charming. He really was. He was a womanizer, of course. The wedding ring that he had shed between May and September of 1964 was already his second marriage. His third wife really was the love of his life, Eve-Marie. She was Danish. She predeceased him of metastasized breast cancer when they were in Europe. She was a wine importer and self-supporting, which made her more attractive than me in many ways! [laughs] After she died, he married a fourth time. He liked women. I think there's no doubt about that. He was really a very, very good advisor in the sense that he had at least a dozen PhD students at Caltech while he was there, and one or two later in Europe, and he saw to it that everybody got a job afterwards if they were job hunting. One of the students opted to go to Australia with her husband, which is perhaps not a—anyway—and his students all got jobs. I sensed they all stayed in science afterwards, which isn't always true. So there's no doubt he was a very good advisor.

He had started his life of course as a theorist with Chandrasekhar in Chicago, and his early papers are on radiative transfer and things like that, the spectrum of the Sun and stars. He got to Caltech brought by Greenstein, who also came from Chicago, and was expected to become an observer, and he worried that he didn't know enough about telescopes and spectrographs and things, but it turned out he did. Late in life, he turned to this theory again mostly to understand things about the atmospheres of the planets and some more about the spectra of Sun and stars. He was both a theorist and an observer, and a very good one, I think.

ZIERLER: Did he collaborate with Jesse? Did they work together?

TRIMBLE: No. Almost no. In those days, senior scientists didn't work with each other, with rather few exceptions. You have to look hard to even think of significant papers with two authors or three from before the 1960s. Greenstein went to Caltech in 1948, I think, and Guido came a couple years later, 1951 maybe. There's one Münch and Zirin paper on gas above the galactic plane. There are a couple of Münch and Neugebauer things. Greenstein did some papers with his students and maybe postdocs, but most of his work was as a sole author. It was characteristic at the time.

ZIERLER: Was Jesse your co-advisor?

TRIMBLE: No, Jesse—I did my second year research project with Uncle Jesse, the white dwarf thing. Guido was my thesis advisor.

ZIERLER: What was it like to work with Jesse?

TRIMBLE: Well, [laughs] I had almost forgotten until he reminded me after some years—he was the only faculty member who ever drove me to tears over scientific issues. I was supposed to be measuring something, I had not a clue how to do it, and he tried to explain it. The more he explained, the less I understood. I finally left his office with tears streaming down my cheeks. [laughs] Jim Gunn chatted with me and said it was all right, he'd tell me what I had to do. And he did, and it was all okay. Jesse was—again, he gave me a project he didn't think I could do, because he had tried and he couldn't do it. He had a computer working for him, Grace Vess, and she couldn't do it. If the head honcho and the computer couldn't do it, why could this long-haired [laughs] slinky Hollywood female do it?

ZIERLER: Was he gracious about it when you proved your mettle?

TRIMBLE: Well, I was second author on the first paper, and first author on the second paper, so yes, I guess so.

ZIERLER: [laughs]

TRIMBLE: We had a tiny run-in on that first paper. Jesse actually spoke very, very clearly, but he didn't write as clearly as he spoke. I saw the first draft of this paper that I was going to be second author on, and I thought my job was to reorganize it so it read like competent English. When I did that, he was very angry.

A Different Side of Feynman

ZIERLER: Let's move on to meeting Richard Feynman. When did that happen? How did that happen?

TRIMBLE: Well, let me put on my glasses. In the good old days, all the women graduate students in Astronomy shared a—we varied in number, from one or two to five—we shared an office in the back of the library so a librarian could act as a dueña. I was walking across campus from a class, and I don't remember which class, but it was in the Spring of 1965. Feynman in those days was learning to draw from Zorthian. Am I going to get Zorthian's first name? Maybe not, doesn't matter. The deal was they were going to teach each other. Feynman will teach Zorthian physics, and Zorthian would teach Feynman art. Feynman learned to draw fairly well; Zorthian never learned any physics.

But I was walking across campus, and Feynman was learning to draw, and he wanted models, and he spotted me walking across campus and started to follow me. I disappeared into Robinson, the astronomy lab, just as Guido was coming out. Feynman stopped Guido and he said, "I'm hunting. Maybe you know the quarry." He described me. Guido said yes, he knew me, and took Feynman back to the office in the back of the library and introduced us. Feynman said would I pose for him, and I said sure. For a while it was Tuesdays for two hours for actually $5.50 an hour, which was a lot in those days, and all the physics I could swallow. I did this quite regularly through spring and summer, and into the fall, of 1965. One day my mother phoned me—October, I had by then an apartment in Pasadena—my mother phoned me and said, "Feynman has just won the Nobel Prize." By the time I got to school at 7:30, I already knew. Richard came into my office. It was a Tuesday. The physics prizes are still announced on Tuesday. Richard came to my office in the back of the library and said, "We have to cancel our [laughs] drawing appointment"—for that evening. I said, "Yes, I know, and congratu…"—I don't know what I said—"Wow, congratulations," or whatever. We continued sporadically after that. But I was among the first to get to congratulate him on the Nobel Prize. That day, he was wearing a jacket and tie, which he hardly ever did.

ZIERLER: Where did the drawing sessions take place?

TRIMBLE: In the basement of his house in Altadena. His wife Gweneth would bring us orange juice and cookies halfway through the two hours.

ZIERLER: Being a graduate student, being drawn by Richard Feynman, did you ever feel uncomfortable? Did it ever feel odd?

TRIMBLE: No. David, you have to understand, I was actually very attractive in my youth. That men would want to look at me dressed or undressed did not surprise me. And Feynman was enormous fun. He had all these stories, many of which are now of course in books, but he told them, live. By the time I was posing for him he was actually very good. I have one drawing of myself, by him, that hangs—I can see it now. It's on my living room wall. It's my second favorite portrait ever of myself. My very favorite was done by the UCLA Egyptologist, Alexander Badawy, and it's chalks and it's gorgeous. Anyway, it was fun posing for him. He told stories. If he didn't say anything, he expected the model to talk. He didn't like silence. I remember pontificating about R Cor Bor stars once.

He always wanted to do science his own way. He wasn't good about taking off from somebody else's ideas. He had to work things out for himself. He didn't much like having graduate students. He said that a PhD thesis was research done by the professor under extremely difficult circumstances, because he couldn't give a problem to a student until he kind of already knew the answer himself. The result was he did not have large numbers of graduate students who became famous, unlike Schwinger. Julian Schwinger had 65 graduate students or something, many of whom became world-class physicists.

ZIERLER: Was Feynman always a gentleman during the artist sessions?

TRIMBLE: [laughs] The answer to the question you're trying to ask is no, but it would not have made much difference if the answer had been yes. The answer was no, not because—he was worried about babies. I was worried about the fact that Gweneth was going to arrive with orange juice in about 10 minutes. [laughs]

ZIERLER: [laughs]

TRIMBLE: Does that answer the question you wanted to ask?

ZIERLER: It does. Thank you, thank you. Did you learn physics from him? Did he just like to talk, or it was actually educationally useful for you?

TRIMBLE: I certainly learned vocabulary. Different branches of science have been even more hostile than astronomy was. The first woman I ever met who sounded like a particle theorist was Glennys Farrar. She's essentially my age and she's up for election to the American Academy of Arts and Sciences this year. I wished I could have voted for her twice. I learned some vocabulary, and knowing the right words in which to ask a question is enormously valuable. It gives you a very different kind of answer. I once met a nine-year-old boy who asked in literally these words, "What is the status of the suggested companions of Barnard's star?" He got a very, very different answer than the nine-year-old who said, "Are there planets around other stars?" I learned vocabulary, certainly. Another thing about Feynman, of course, is when he gave public talks and lectures at conferences and taught class, you always came away from one of his lectures enormously inspired, but you usually couldn't do any calculations you couldn't do before. I'm not the only one who said this. It was characteristic of his presenting things that you'd come away inspired and wanting to work on them but you wouldn't quite know where to start to do the next calculation.

ZIERLER: Did Feynman take you seriously as a scientist? Did he ever take an interest in your research?

TRIMBLE: He listened, sometimes. Yes, and in fairness, he is thanked in my thesis because he actually read some chapters and provided advice.

ZIERLER: Virginia, who else was on your thesis committee?

TRIMBLE: Good question. Feynman was not, I don't think. Certainly Harold Zirin, because he is the one who coached me through the qualifying exam. Uch! Bev Oke. Jesse. And I think Wal Sargent. Oh, I'm sorry, no, the qualifying exam committee included Robert Leighton, who found me totally incompetent and decided that my PhD could not be Astronomy and Physics. I just didn't know enough physics to please him. It was five. Both the qualifying exam committee—which was an oral in those days, three hours, and the PhD exam were orals—with five faculty. The PhD exam was fun because when you're defending your thesis, you know more about it than anybody else in the room, so defending a thesis is a fun exam. The oral qualifying was not a fun exam! [laughs]

ZIERLER: They put you through the wringer?

TRIMBLE: Well, I failed, is what it comes down to. I failed the first time around. There's no doubt about that. I had to do it a second time, and Leighton still wasn't satisfied.

ZIERLER: What did you improve upon the second time around?

TRIMBLE: In the 10 weeks in between, Harold Zirin very nobly had coached me, once a week, on things like how does Mössbauer scattering work, how do lasers work, things like that. High powered new technologies depending on new physics. The qualifying exam, I had assumed it would cover what we had had in class, but it didn't. It covered things like what was in Scientific American over the past year, what was in the colloquia in Physics and Astronomy over the past year. I had actually missed colloquia for a good part of a quarter because I was dating a guy who expected me to turn up at 5:00, so I couldn't go to colloquia for a long time. He went off to Japan for two weeks, and—well!—I got to go to colloquia.

I wasn't prepared for the qualifying exam because I didn't know what was going to be on it. The guys all knew. People had been keeping track of what the questions were and who asked what, and they had a notebook and passed it around so that people went to the qualifying exam knowing what things they were going to be asked. I was out of that particular social circle. The gal who took the exam the same year I did, Vicky Peterson, her husband was also a graduate student, so she saw the notebook, so she did just fine on the qualifying exam. Afterwards, there was at least one faculty member who said he was terribly puzzled that Vicky did so much better than Virginia, because he thought Virginia was smarter. I don't think that's true [laughs] but he was surprised how badly I did. It was because I had never seen the questions before!

ZIERLER: What about Jim Gunn? Did he serve in an advisory capacity to you at all?

TRIMBLE: [laughs] Look, back in 1960-whatever, most of the things that went on would get us all fired these days! [laughs]

ZIERLER: Yes, a very different time.

TRIMBLE: [laughs] In fact, I pulled out my copy of Jim's PhD dissertation quite recently, because I'm going to talk about weak lensing. His PhD dissertation actually was what is now called weak gravitational lensing. It wasn't called that, then. I pulled it out because I'm going to be giving a talk for the American Physical Society in April as the winner of the Pais Prize. I pulled that out to talk about weak lensing. Anyway, yes, we were very close. Does that answer your question? [laughs]

ZIERLER: Yes it does. Yes it does.

TRIMBLE: Of course Guido was angry with both of us. I don't know whether it is of any use or not, but nobody was ever jealous of Feynman.

ZIERLER: You mean due to his fame, nobody was jealous?

TRIMBLE: I don't know what it was. But Guido was—controlling, I suppose, is the right—I don't know—Guido was seriously jealous of Jim Gunn. He was seriously jealous of Peter Scheuer. But he was never jealous of Feynman. I mean, in connection with me. I don't know what that means. It has puzzled me on and off for [laughs] 50 years now. Jim was the one who dried my tears when Jesse drove me to distraction over how to measure the white dwarfs, and he taught me several other things—of course how to calibrate the plates of the Crab Nebula's emission lines. He had invented and built an instrument that turned nonlinear H&D curves into something pretty much linear in the number of photons that hit the plate. I scanned those plates with that device and he taught me how to use it.

ZIERLER: Virginia, was JPL, the Jet Propulsion Laboratory, an asset for you at all? Did you ever spend time up at the Lab?

TRIMBLE: As a scientist, no. [laughs] After Jim was working there, we used to meet fairly often underneath a particular willow tree on the grounds of JPL.

ZIERLER: [laughs]

TRIMBLE: That was a long time ago! I never worked there. I've been there since then, of course, but not as a student.

ZIERLER: What do you see as the main scientific conclusions of your thesis?

TRIMBLE: The Crab Nebula is at a distance of two kiloparsecs, and the expansion has been accelerated by the right magnetic field which is order 10-4 gauss, and a corresponding energy density in relativistic electrons that accounts for the synchrotron emission, all the way from X-rays to radio. That supply of electrons has to be kept up, and how that supply of electrons was kept up was a major puzzle in 1964, 1965, 1966. Even for the optical emission, it was kind of on the ragged edge. When the X-rays were discovered in 1964 or 1965, it became a real issue, and therefore the pulsar in the Crab Nebula was a godsend for all of us. By then I had by PhD.

Cambridge and the Paczyński Code

ZIERLER: Did you want to move on to other things after Caltech, or did you want to stay with Crab Nebula research?

TRIMBLE: Oh, I had some very, very good advice. It came from Lodewijk Woltjer. Yes, [laughs] I was also engaged at one stage, and I still have the ring! [laughs] He had a view from his days I think working with Jan Oort in the Netherlands that when you finish your PhD, you should give that topic a five-year sabbatical and not return to that topic for at least five years. I kind of did that. I went and worked on other topics—things in stellar structure and evolution—using the Paczyński Code which I got a copy of in 1969 at the summer school at Stony Brook. I did structure and evolution of stars for a while with that. I did binary stars and various other things. I came back to the Crab occasionally and contributed—well, Woltjer and I had one paper together on it, persuading ourselves if nobody else that there was no extra material at low temperatures hidden in the cores of the line-emitting filaments where there could have been. It's still kind of a puzzle where all the mass is, that that star must have had. There's a couple in the neutron star and a couple in the nebula, but it must have started out with like eight or ten.

I did a few Crab Nebula things in my two years in Cambridge, a couple of them with Martin Rees. There's a paper called "Planet, Pulsar, ‘Glitch' and Wisp"; that's Rees, Trimble, and Cohen. There's something on the expansion energy, I think, or the expansion center, that was I think more or less correct, things that appeared in Monthly Notices or Nature or conference proceedings. Then I started doing the stellar structure with Paczyński. That was an interesting exchange, because he was in Poland, and I was in Cambridge, and then I was in the U.S. We wrote back and forth to each other, frequently, and each letter had to be read on both sides, because a wicked capitalist country, a wicked communist country, people couldn't exchange letters with technical content without somebody reading them! [laughs]

ZIERLER: [laughs]

TRIMBLE: Our colleagues didn't care. Our colleagues were in favor of it, because he was brilliant. That structure code, the Paczyński Code—still forms of it are in use—was the first open source astronomy computer code where you could get everything about it and all the instructions, and exactly what each step did, and make whatever changes you wanted. If you wanted to describe a star with a different composition or a different rule for the interface between radiative and convective transport, or a different rule for opacities, you could play with it. You could make changes. I did that, mostly with his advice—entirely with his advice. And—yes. [laughs]

ZIERLER: A few questions on the social and political side during your time at Caltech. In the 1960s, was the campus at all politically oriented? Were people talking about Vietnam or race relations or women's liberation?

TRIMBLE: Hardly at all. I almost missed the 1960s, you know. [laughs] It didn't happen at Caltech, and it really didn't happen at Smith College! There were a couple things that we were aware of. One was President Johnson's poverty line. A bunch of us were at some social event—I don't remember now which one—and realized that we were all beneath Johnson's poverty line, but we wouldn't always be there, so it was okay. Then the Peace and Freedom Party was trying to get on the ballot in California, and a bunch of us dropped whatever party we had been registered with—I was a Republican in those days, because my parents were Republicans, at least my father—we dropped our registrations and registered for the Peace and Freedom Party to get it on the ballot. Then I went back to being [laughs] something normal after that. So, there was some awareness. There were also people of course who went to Vietnam, including Jim Gunn, who had been in ROTC in Texas to pay for his education and therefore owed the government a couple of years. He did one year at JPL and part of a year in Vietnam. But most of us were not very politically aware, I think it's fair to say.

ZIERLER: Of course in 1970, Caltech finally made the decision to go co-ed, admitting women undergraduates. Were you aware of any of those conversations? Did you participate in them?

TRIMBLE: No, I was gone by then. The little bit of that that I was aware of was Jenijoy La Belle, the first woman hired on the faculty, in some humanities-y type department. The department did not want to give her tenure, and she made a big fuss and got tenure, and I thought it was very tiresome of her.

ZIERLER: You don't recall faculty members ever debating the question of admitting women undergraduates? That must have happened after you left.

TRIMBLE: Well, or it wasn't something they shared with graduate students. Or they weren't very interested, either. They certainly weren't talking about it except a few special cases, where somebody came with a package deal with a thesis advisor or with a spouse that they really wanted the guy, in graduate school. At the undergraduate level, at the time they didn't actually have living facilities for women. The men graduate students could live in dormitories but women had to rent apartments. The economic issues were serious; let me just leave it at that. I don't know who really was making the push for women undergraduate students. I don't think it was Astronomy.

The First Among Many Women Astronomers

ZIERLER: Your admission as an extraordinary exception, did those rules relax during your time at Caltech? Were more women graduate students getting admitted that didn't have a package deal?

TRIMBLE: In Astronomy, yes. I was the first admitted on my own, and the reason was that I had this fellowship where I couldn't stay at UCLA. The gals who came after me—Judy Cohen was in effect part of a package deal because she thought—and initially he thought—she was engaged to somebody who came the year before. Then he dumped her. Donna Weistrop was certainly admitted entirely on her own. Sue Werner, who moved over to Geology and became Sue Kieffer after a year or so, came as a student of Harold Zirin when he joined the faculty. He had been at Colorado and she had been his student at Colorado in Astronomy. She was in our girls' office for a summer and then moved over to geosciences. Anneila Sargent came with her husband who came on the faculty, Wal. I think that takes care of the lot. It was then like a decade before there was another woman who got her PhD in Astronomy. There were a few gals in Physics. Jean Swank, I think.

ZIERLER: Do you think your research accomplishments at Caltech helped to pave the way for other women graduate students, or convinced the faculty that women really should be a bigger part of the program?

TRIMBLE: I shouldn't think so. If I convinced them, I think it was women were a nuisance! [laughs]

ZIERLER: [laughs] For the last part of our talk, a few reflective questions. What has stayed with you from your Caltech days? What do you remember fondly and not so fondly?

TRIMBLE: [laughs] Fondly—the fact that it worked, that it all became possible. My father was a chemist, quite a good chemist but a rather poor businessman, and he tapped out with a master's degree just after World War II. But I think my parents never doubted that I would go to college, that I would get a PhD. My father used to say, "A PhD is not a union card. It's something you do for yourself." [laughs] It has become a union card, and that's kind of sad. I think we had a lot more fun than most graduate students do now. There was no question of there being a firm 40-hour limit, 20-hour limit, on the number of hours we could work for somebody else. The one year that I didn't have a fellowship I was paid as a research assistant. It was Jesse's money because I was doing the white dwarf project. It didn't occur to anybody that there was a limit on the number of hours I was allowed to work on this. Mostly it was a lot of fun. And a lot of fun with the guys. When I arrived, there were 14 women in the entire campus directory excluding secretaries. You put 14 women down among 1,400 men, they're going to have a lot of fun. [laughs] That's life! It was a wonderful place to learn things. There's absolutely no doubt about that. Cambridge was equally wonderful.

ZIERLER: What did you learn about what it takes to succeed as a scientist that has stayed with you from Caltech?

TRIMBLE: Nothing. I'm not aware of having been consciously influenced in this way. I had very good luck with three people all of whom turned out to be, A, morning people, and B, thinking that hard work was a good thing—my father, my thesis advisor, and my husband. I continue to think that hard work is a good thing, which is how I got all my papers graded before this [laughs] conversation, because I started at about 6:30 this morning!

ZIERLER: On that note, one final question to wrap up our discussion—have you remained connected with Caltech? Have you been an active alumnus over the years?

TRIMBLE: Not very. I've been invited back to give talks twice. I've been invited back to do other things a few times. I was elected to the Alumni Association board of directors, and they told me I'd have to come up about once every three months. It turned out the first month I had to come up three times. But what really drove me to resign from the board of directors was the following: I had been on it for maybe a year, and there came up the issue of a paper directory of the alumni. I still have the last one that was issued as a paper version. It was decided that it was too expensive to produce a paper alumni directory. At the same time at that meeting it was announced that they had just committed $60 million to a new dormitory. The alumni directory would have cost about one percent of that, maybe even a tenth of a percent of that. I said to myself, this organization is not doing things where what I can do will be useful to them or to me, so I resigned from the board of directors of the Alumni Association.

ZIERLER: You made your own choices.

TRIMBLE: Well, you can't make choices for anybody else! They won't do what you want! [laughs]

ZIERLER: [laughs]

TRIMBLE: And letting other people make your decisions doesn't work very well either! [laughs]

ZIERLER: It has worked for you; there's no doubt about that.

TRIMBLE: I also married a man who I had known him 11 days. [laughs]

ZIERLER: [laughs]

TRIMBLE: Portions of 11 days, and that lasted twenty eight and a half years until he died.

ZIERLER: Virginia, this has been a lovely conversation. I want to thank you so much for sharing your memories with me.

TRIMBLE: Thanks for asking.

[END]