Notice: We are in the process of migrating Oral History Interview metadata to this new version of our website.
During this migration, the following fields associated with interviews may be incomplete: Institutions, Additional Persons, and Subjects. Our Browse Subjects feature is also affected by this migration.
We encourage researchers to utilize the full-text search on this page to navigate our oral histories or to use our catalog to locate oral history interviews by keyword.
Please contact [email protected] with any feedback.
Credit: Hong Kong Institute for Advanced Study
This transcript may not be quoted, reproduced or redistributed in whole or in part by any means except with the written permission of the American Institute of Physics.
This transcript is based on a tape-recorded interview deposited at the Center for History of Physics of the American Institute of Physics. The AIP's interviews have generally been transcribed from tape, edited by the interviewer for clarity, and then further edited by the interviewee. If this interview is important to you, you should consult earlier versions of the transcript or listen to the original tape. For many interviews, the AIP retains substantial files with further information about the interviewee and the interview itself. Please contact us for information about accessing these materials.
Please bear in mind that: 1) This material is a transcript of the spoken word rather than a literary product; 2) An interview must be read with the awareness that different people's memories about an event will often differ, and that memories can change with time for many reasons including subsequent experiences, interactions with others, and one's feelings about an event. Disclaimer: This transcript was scanned from a typescript, introducing occasional spelling errors. The original typescript is available.
In footnotes or endnotes please cite AIP interviews like this:
Interview of Frank Shu by David Zierler on May 27, 2021,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Interview with Frank Shu, University Professor emeritus at UC Berkeley and UC San Diego, and Founder and CEO of Astron Solutions Corporation. Shu describes his current work on climate mitigation through his company, Astron Solutions Corporation, and he reflects on how his expertise in physics is useful for this endeavor. He recounts his family origins in Wenzhou, China, and their experiences during the Japanese occupation. Shu describes his family’s journey to the United States through Hong Kong and Taiwan, and the opportunities that led to his undergraduate study in physics at MIT. He describes his early interests in gravitational collapse, and he explains his decision to pursue graduate research at Harvard, where he worked on density wave theory of spiral structure under the direction of Max Krook. Shu explains his broader interest in star formation and his work at Stony Brook before taking a faculty position at Berkeley. He describes the “inside out” collapse model and the formative influence of Peter Goldreich. Shu explains how he came to lead Tsing Hua University and his achievements in raising its stature before joining the faculty at San Diego, and he discusses his original interests in climate change research. He describes the Heat Exchanger (HX) Project and how his research on nuclear energy has therapeutic benefits for cancer patients. Shu discusses his patent on sealed carbon fiber reinforced carbon nanotubes and the hurdles that are preventing the widespread adoption of molten salt technology. At the end of the interview, Shu describes the importance of taking multi-pronged approach to climate mitigation and that humanity’s best response at this point is to recognize climate change as an emergency.
Okay. This is David Zierler, oral historian for the American Institute of Physics. It is May 27, 2021. I am delighted to be here with Professor Frank Shu. Frank, it’s great to see you. Thank you for joining me today.
Yeah. Thanks for having me on.
Frank, to start, would you please tell me your current title and institutional affiliation?
Okay. I have an emeritus status in the University of California. There’s a level called University Professor, which is actually a lifetime appointment. I’m University Professor Emeritus at Berkeley and at San Diego.
What year did you go emeritus, Frank?
In 2009. I’ve actually done it twice (laughter). In 2002 I retired from Berkeley to go to Taiwan to work. I was president of National Tsing Hua University from 2002 to 2006. I came back and San Diego made me an offer I couldn’t refuse, so I went to San Diego for three years and then I got interested in climate change. That’s when I took my second retirement in 2009. I have also founded a company, Astron Solutions Corporation, of which I am Founder and CEO.
Frank, we’ll take your personal narrative all the way up to the current, but for right now, just as a snapshot, what are you working on? What is the science that’s most important to you?
Just now? I’m working on climate change mitigation. My company, Astron Solutions Corporation, does two things, both in molten salt and involving carbon technology. One of them is traditional in the sense that it sort of started the whole molten salt game, which is advanced nuclear reactors. We think we’ve improved upon the original work that was done by Oak Ridge National Laboratory, and that’s, hopefully a path to help to get us to zero emissions.
Zero, as everybody now feels, is not enough. We’ve already gone past the point of a maximum permissible amount of carbon dioxide released into the atmosphere, so the second technology is to remove enough of that carbon dioxide so that we get to a safe level, what we had back in 1988, when it was 350 ppm in the atmosphere. That we do by making use of biomass.
Now if you look at the carbon dioxide budget due to biomass, it’s on average zero because when it’s growing, it absorbs carbon dioxide out of the atmosphere. When it dies, it releases back carbon dioxide and other greenhouse gas back into the atmosphere. So, it goes up and down, about eight ppm a year. Now if you could prevent it from going back up, you can get the negative eight without getting the positive eight. If you wanted to reduce atmospheric carbon dioxide by, let’s say, one hundred ppm, well, you can do the division yourself: eight into one hundred is twelve and a half years. But that’s impossible because you cannot possibly use all the biomass that grows in a year.
Then the question becomes what fraction can you use? I think a reasonable fraction is about a quarter, so you know, fifty years instead of twelve and a half years. The way to do it is to prevent the dying biomass from rotting, and that we know how to do. We’ve known how to do that for many millennia. It’s probably the second-oldest technology in the world (laughter).
The oldest is fire. But soon after that, people found if you didn’t burn the wood completely, if you lacked a little bit of oxygen, you get leftover charcoal. And charcoal lasts forever (laughter). It doesn’t get degraded. Organisms cannot digest elemental carbon, which is what charcoal is, about eighty percent by weight. So, if you have a bag of charcoal, you don’t have to worry about it rotting, right? You can have it in your garage. You don’t have to refrigerate it (laughter). It’s never going to smell. It’s going to last hundreds of thousands of years. It’s as simple as that. Turn as much as possible of the biowaste from agriculture, from forestry waste, from yard waste even, into charcoal. And in fifty years we’ll reverse climate change.
Frank, I’m curious in your work on climate mitigation, the extent to which you’ve drawn on your expertise in physics specifically, or is this more about being a scientist who knows how to solve problems generally?
Well, that’s a good question! I think my training as a physicist and as an astrophysicist helps a lot, okay, because of course, in the first project, nuclear reactions, that’s a lot of what astrophysicists do, okay? It’s energy conversion in the universe. A prime example of that are nuclear reactions in the sun, and the sun, I think everybody would agree, is a very safe form of energy. It’s been safe for billions of years, right?
Now if you ask, “Why is the sun safe?” it turns out it’s for the same basic reason why molten salt reactors are safe. They both have what is called technically a negative coefficient of thermal reactivity. Namely, when things get hot in the core of the sun, the core expands and therefore it cools itself. The same is true of molten salt. It’s a liquid instead of a gas, so it doesn’t expand as much, maybe only twenty percent, but twenty percent is good enough. So, it’s automatically safe. If you are overheating, it expands out of the core and lowers the rate of reaction. It’s as simple as that. When I saw that property of molten salt reactors, I said, “Wow. That’s a great reactor because it works exactly the way the sun works.” I had to teach courses in stellar structure and evolution, so which helped me to immediately recognized that commonality.
The carbon aspect is also interesting because in astronomy, after hydrogen and helium, the next two most abundant elements are carbon and oxygen. In fact, which one is more abundant determines to a large part of what can become solids and liquids in the universe. Now without solids or liquids, life on Earth wouldn’t exist. Solids and liquids, condensed matter, are a very important part of the terrestrial domain. Of the universe as a whole, they’re relatively minor. The universe is mostly plasmas and gases, but nevertheless, solids and liquids are very important for life on Earth. That is known to every astronomer.
If you’re in an environment where oxygen dominates over carbon, you’re going to get solids that are basically rocks, because silicon is very abundant and silicon plus oxygen gives you silicates and that’s quartz. Quartz is a rock. In fact, half the atoms on and in the Earth, a rocky planet, are oxygen atoms. In the biosphere, carbon is abundant, you get carbon dioxide (or carbon monoxide), which is, of course, a greenhouse gas. That part is also very natural and something that an astrophysicist would immediately appreciate.
In recent decades, there’s all this hoopla about materials made purely of carbon. Graphene is a new wonder compound of interest to materials scientists, right? It can make all sorts of things from semiconductors to nanotechnology, etc. In these interdisciplinary fields, there’s really no separation between what is chemistry and what is physics.
Frank, after a life spent in the academy, has it been fun being an entrepreneur in the world of business?
Yes and no (laughter). It’s much harder in some sense because when you are an academic, the final product is limited in scope, right? It’s a paper. Once you’ve written that paper, you go on to the next paper or the next problem, so it’s more or less all under your control. Of course, referees have something to say about whether your paper gets published or not, but that’s what graduate school training teaches: how to answer those kinds of questions, both standing up and on paper.
In business, that’s not the bottom line, unfortunately. Now, you have to make a transition from research and development to manufacturing a product, and that product has to be something other people want, not that just you are interested in- that people want to buy. It’s a whole different world, right? With such transactions, especially with something like nuclear energy, comes government regulation. Government regulation is important and necessary. It’s what prevents businesses from unsavory practices. Nevertheless, it means a lot of additional work to make sure that your product is not only something that people want to buy, but that it’s safe for them to use in the long run.
A lot of the problems in the modern world are because we haven’t regulated well. If you talk about carbon, apart from elemental carbon, you have the whole fossil fuel industry and the plastics that they make. Now plastics are a wonderful thing, but they also result in big problems if you only worry about the production end. I think that’s what’s gone wrong with our whole way of doing business today. Capitalism mostly worries about the front end. Once you’ve made it, what happens to the product that everybody has bought? That’s somebody else’s problem. But that’s not true, is it? It’s everybody’s problem. There are plastic now all over the oceans. The microplastics are in the drinking water. Their being everywhere leads to all sorts of bad consequences.
Frank, I wonder how, on both the science side and the business side, you have fared during the pandemic and the requirements of remote work.
Well, it has set us back like it set everybody back. We have a schedule that we would like to do things. We’re in the process of producing a prototype machine to do what we call supertorrefacation, that is, quickly turn biomass into various forms of charcoal, which includes activated carbon, for filtering contaminated water. Activated carbon is a remarkable material. In some sense, it’s the first application of nanotechnology in the world. Because of the pandemic, we basically have slowed down to a snail’s pace in this work.
Now, it’s also a financial drain because I continue to pay employees. I don’t want my people to not get paid because of something that’s not their fault. Somebody has to pay them until we have a product that other people want to buy. So, I’m personally supporting this activity right now. Fortunately, my own requirements- I have a wonderful wife- are not great. I can afford this extra drain. But the pandemic has been a setback.
Frank, this might be a painful question, but it’s one that I think is very important to discuss at this point. It’s very troubling that we live in a time where Asian Americans are feeling a bit unsafe, that there has been violence, that there is discrimination. I wonder what your perspective on this is as an Asian American and specifically as a scientist, because there’s so much about misunderstanding with science that’s at the root of these things.
Well, Asian Americans, I think in general, like to keep a low profile, especially those in science and technical fields. In fact, I can tell you that lots of Asians got into science and into technical fields, engineering, because of an innate sense of discrimination elsewhere. We’ve been taught since we were small that science is more objective than other subjects, right? Good people are recognized for the right reasons, and if you fail, it’s usually also for the right reasons. So that objectivity is what caused, I think, the initial wave of Chinese Americans (the educated class) to go into technical fields, to become scientists and engineers.
There’s also a class of Asians who I think feels this discrimination much more, and these are the people who came to work on and build the railroads. They also built and occupied Chinatown. They run restaurants. They run all the traditional things that are stereotypically Chinese- laundries, right? They are the ones who are actually suffering the brunt of the discrimination and hate crimes.
It’s not that there isn’t bias in the professions. I used to serve as the Chair of a committee that was established at Berkeley because Berkeley was found wanting in the way that it admits students. There were affirmative action initiatives taken to admit more Hispanics, more African Americans, and more indigenous peoples. When you admit more Hispanics, African Americans, and indigenous peoples, which is a good thing, you’re going to have to admit fewer of some other class of students. In Berkeley it was found that that this other class was Asian Americans. It’s not surprising. If you go to the Berkeley campus, you see a lot of Asian Americans. We’re over-represented in academia for the reason I mentioned. Nevertheless, that’s not fair to discriminate against us now because you discriminated against others in the past, right?
So, there was a committee set up to look at this problem. As Chair of the committee, I posed a question when we were discussing what exactly is the concept of fair? I said, “Well, in an ideal world, Asian Americans will be represented at the proportion of eligible faculty, but we’re not. Yes, we have lots of students, but on the faculty we’re under-represented. Why is it that at every department where you find Asian Americans on the faculty, they’re among the top people in the field? In a fair market, shouldn’t there be some crummy professors as well?” (laughter) It’s subtle things like that that you have to call people’s attention to. I said, “You know, you can make the excuse that the eligibility pool is low among African Americans, among Hispanics, among indigenous peoples. You cannot make that argument when it comes to Asian Americans. The eligibility pool is high, yet the faculty representation is low.” Of course, these problems are inevitable in any society, and I have to say I worked at a lot of institutions in a lot of countries. The U.S. is, on the whole, relatively good about this kind of introspective examination.
That’s good to hear.
Everybody talks about it, is open about it, and is open to change. I think that it used to be the single best feature of American society. What I worry about, to answer your question fully, is today we see pushback, you know, overt expressions that people of color are displacing whites. Whites have become a minority, and they feel threatened by that development. I don’t know why, but it is true.
Well, Frank, let’s take it all the way back to the beginning. Let’s go back to China and start first with your parents. Tell me about them.
Well, my parents come from a city in China called Wenzhou. Wenzhou is known for its diaspora. You’ll find people from Wenzhou all over the world because people from there are very entrepreneurial. My father’s side of the family was very poor. They were of the peasant class until my great-grandfather. Now in China, which is a very caste-bound society, there was social mobility through examinations. You may know about this. Imperial examinations were given every year, and people who did well on those exams could become part of the civil service. In that way, peasants could become part of the middle class and even part of the management class. My great-grandfather took that exam and became a magistrate. So, he was the first person of any distinction on my father’s side of the family. By the time he retired, he was a very wealthy man, and very famous as well as admired.
He returned back to Wenzhou, the place of his birth, on a boat. His ship was caught in a dense fog and rammed by a British warship. My great-grandfather sank with the boat, died as a consequence. So, the whole province, Zhejiang province, went into seven days of mourning. The males of the family went into mourning for seven years; the women, for one year. During this period of mourning, nobody could eat fish because some fish might have eaten my great-grandfather (laughter). Even my father got caught up in this superstitious behavior, and he gave up eating seafood for his entire life. Nevertheless, you can appreciate from that example what a traumatic thing it was for my family.
Well, my grandfather and his brothers went to the British consulate to complain and they were executed. So, the family fell into poverty. My father, who was just a boy, was left as the head of the family and had to dispose of all the valuables that the family had to pay the bills. We basically rose up to a very high station in life and fell, crashed down back into what would be worse than being a peasant.
It scarred my father, obviously, but fortunately, my uncle’s family took him in and raised him as a boy so that eventually he could go to college. He was admitted to Tsing Hua University, which is one of the two top universities in China, and was later sent out- I’ll tell you that story when we finish this one- to come to the States. So, he’s always felt very grateful to my uncle and his family.
As a consequence, when my uncle’s kids became college age and wanted to come to the United States where my family was by then, we took them all in (laughter). And that was a big family. My uncle had ten kids, and every single one of them at one point lived in our family, went to college, and my parents basically supported them while they lived with us. So even though my father was a professor at that point, professors don’t make that much money, so we were still hungry all the time! (laughter)
Frank, where did your parents meet?
They met when they were in high school in Wenzhou. My father and mother got married quite early. I think he was twenty-one, she was eighteen. She never went to college. She was a schoolteacher.
What was their experience during World War II and the Japanese occupation?
Most my personal memory is that the experience was horrible. I was born in 1943. At that point, the Japanese had taken over the entire eastern seaboard of China. If you know the geography of China, you know that the populous area is all on the eastern coast, from Beijing down to Shanghai down to Guangdong (Canton) province at Hong Kong. Instead of giving up, the Chinese retreated. Under a policy of burning the fields behind them, they retreated to the western part of China. The universities were part of that retreat, as well as the factories. There’s a wonderful story of how they dismantled the factories, carried them on the backs of animals and humans, and brought all that stuff to Yunnan province, to the city of Kunming, where I was born. Because of that exodus, my middle name in Chinese, “Hsia-San”, means “born in a faraway place” (laughter).
I was born not in Wenzhou, the ancestral home, but in a faraway place, Kunming. My father, who was at that point an instructor at Tsing Hua, brought the family there. Later he was sent to the United States on a scholarship. Now Tsing Hua University has an interesting story. It was founded in 1911. If you know your Chinese history, 1911 was the year of the founding of the Republic of China. Tsing Hua was founded for an express purpose, which was to send students abroad to learn science and technology so that China would never again suffer the humiliating defeats that it did during the Opium Wars and the Sino-Japanese War.
In fact, the money for founding Tsing Hua came from the United States.in the aftermath of the Opium Wars, when the victorious powers extracted a huge sum called the Boxer Rebellion reparations. The United States, one of the seven allies in the war against China, to its everlasting credit, gave back its portion of the Boxer Indemnity money for educational purposes. Tsing Hua used the Boxer Indemnity scholarships to send students to America to learn science and technology. My father was part of that first group of students that was sent out.
Now there is a scurrilous fable in China that my father was sent to the United States to learn atomic bomb technology (laughter). This is nonsense! That’s the last thing that the Americans would give to anybody else, right?! He was actually sent out to work in helping develop aircraft technology, which he did as an applied mathematician. Many of his best friends went into aeronautical engineering for the same purpose. My advisor at MIT, C. C. Lin, also an applied mathematician, was expressly sent to Britain to work with G. I. Taylor to learn aerodynamics and hydrodynamics because China at that point was flying Soviet biplanes. Such biplanes against zeroes are no match at all! Those biplanes were quickly shot out of the sky. So, the physics professor at Tsing Hua told the students, “The most important thing that you can do now is not physics, but aeronautical engineering.” So, a lot of them took that advice seriously, left physics to work in hydrodynamics and aerodynamics.
Lin was going to England. That’s like jumping from the frying pan to the fire during World War II (laughter). Of course, he couldn’t go to Cambridge, England to work with G. I. Taylor, so he went to the University of Toronto in Canada to get his MSc, and then to Caltech to work with Theodore von Kármán. Not a bad choice, all right? Von Kármán, of course, is the guy who founded JPL. That was Lin’s story. My father had a similar kind of story. He was going to go to Caltech and work with von Kármán, too, but Brown University gave him an offer that paid more, so he went to Brown instead. He had a family to support.
Frank, did he take his family with him initially, or he went first to the United States?
My father came by himself. When I was two months old, he left China and I did not see him until I was six.
You didn’t see him once.
I didn’t see him once. How could he come back? It was the Second World War. Immediately after the war, he wanted to go back, but of course China was then in chaos. The Sino-Japanese War had transformed into the Civil War in China. The times were terrible in those days. Eating a rat was a treat, okay? I remember we also ate birds. So, when people say, “Well, coronavirus jumped from wild animals to humans,” and people say, “Well, how could Chinese eat things like that?” the answer is when you’re hungry, you’ll eat anything.
Yeah. Was there a concern with your father being an intellectual that your family was in danger during the Communist Revolution?
Well, my father, like everybody else at that time, had to make a decision whether he was going to go back to China, which was always his intent, or to remain in the United States. All his friends had to make that choice. He decided he did not want to live in a communist country, so he sent for the family and that’s when we came to the United States.
Now a lot of his friends, I remember, did decide to go back to China. Two of them you may know about. One was Qian, who was also a von Kármán student, and he went back to China and became the father of the Chinese atomic bomb program, as well as their aeronautics and space program. The other was in a less sensitive field. He was a mathematician, Hua Luogeng. Now this man- I’m sorry, I don’t know if these stories are interesting to you.
I asked. Of course it’s interesting!
Hua Luogeng is a legend, all right? He was a good friend of my father for the following reason. My father used to spend a lot of time in the Tsing Hua library when he was a student, and one day he saw this custodian, a janitor, reading a math journal. So, he said, “How come you’re reading this math journal?” He replied, “Well, I like mathematics, but I have a problem.” My father asked, “What?” He said, “Well, I can understand the equations, but I don’t understand the English” (laughter). My father helped him, and this was the beginning of their friendship. Hua did not have any education beyond sixth grade, yet he became one of the twentieth century’s greatest mathematicians. Had he stayed in the United States, his renown would even be greater. Anyway, this person could do applied mathematics or pure mathematics. He was just a free-roaming intellectual.
Hua decided to go back to China, and the FBI knew my father was a good friend and interviewed my father in our Chicago apartment. I remember the occasion distinctly. You can imagine in 1949, 1950 when all this was happening, this was the era when Joseph McCarthy terrorized the United States, so it was a very sensitive time for Chinese Americans.
Frank, what were your earliest memories of either coming to the United States or getting settled in?
Well, we took a boat from China, first from Hong Kong to Taiwan where we stayed a year. That year turned out to be important later because it qualified me to be a president of a Taiwan university because I had resided in Taiwan as a five-year-old for a year (laughter). From Taiwan, we took a steamer in third class to the United States. My brother and I had great fun on that boat, but it was a rough Pacific crossing in choppy waters.
We got off in San Francisco and went to Angel Island, where we were deloused and cleaned up so that we could enter the country. Then we took a train to Chicago. My fondest memory of that train ride across the country was there were these servicemen on the train, and my brother and I were running around. I was six, he was eight. One of the servicemen motioned to me. “Come here.” I came and he had a bag of licorice and he gave me one. He said, “Do you like it?” I didn’t know what he was saying, but I nodded. It was really good- candy! We had never had candy before. He gave me the bag! So that was my first impression. Americans are rich and they’re generous (laughter). So, I was happy to be in America.
We came and lived on the south side of Chicago. I don’t know if you know Chicago at all, but the south side is not genteel. It’s a dangerous place to live, My father didn’t want us to go to the schools near the Illinois Institute of Technology where he worked, so he checked into a boarding house to live with an American lady who had been a missionary in China. She took in school children so that they could attend this better school in that neighborhood. Since my older sister, my brother, and I didn’t know any English, all three of us got put into first grade so that we could learn the language (laughter). After we picked up English, we went to our separate classes, and I finished first grade. I tell people I’ve actually gone to first grade three times. So, I know that material really well (laughter). Once in China, once in Taiwan, and once in the United States. I spent one year each in first grade in each of those places.
In China, I was only four. All my brothers and sisters and cousins were going to school, so I told my mother I wanted to go to school. She said, “You can’t go to school. You’re only four.” I said, “No, I want to go to school. You taught me. I know this material. Let me go to school,” so she gave in and let me go take the entrance exam. I took the exam and they placed me in third grade. My mother said, “No, you can’t go to third grade. You’ll be ahead of your siblings and cousins. Not good for you.” So, she made me go to first grade.
Something terrible happened to me in first grade in China. It affected me the rest of my life. I was the youngest and smallest kid in my class of first graders, so I became the teacher’s pet. Now in China, discipline is a very important thing, and so when kids misbehave, the teacher will whack them with a ruler, all right? The teacher didn’t want to do that, so since I was the teacher’s pet, the teacher said, “Frank, you whack them with the ruler.” So, I whacked them with that ruler. Of course, I didn’t like doing that, so I tried to do it as softly as I could, but nevertheless the remorse of giving pain to others stayed with me.
Ever since then, I’ve never liked being in the position of responsibility where I had control over people’s lives. I much prefer being number two. Eventually that became not possible, but to this day I don’t like that aspect of having power and responsibility. Now, the two are inseparable. When you separate the two, you get into lots of problems. If you have power, you’ve got to have responsibility. If you have responsibility, you’ve got to have power; otherwise you can’t do anything.
Frank, was there a period of transition in getting to know your father from not seeing him since you were two months old?
Yes. Since my father didn’t know me as well, I always felt that he preferred my older sister and my brother, and that was probably true, at least in the beginning. Fortunately, my brother was really a nice person and always shielded me. After my mother was pregnant with my younger sister, my father would sometimes get frustrated over having to live with all these kids and not having a big salary, so he would make idle threats, like, “Well, we’re going to have to send Frank back to China because we can’t afford this large a family.” My brother would go to my father and say, “No, Dad. If you want to send anybody, send me. Frank’s too small.” That would calm my father down and he would say, “Of course I’m not going to send anybody back to China.” But my brother and I bonded in this great relationship because he always took care of me, always took my side, always protected me.
Anyway, when we were young, we had to try to help with the family finances. My brother was very entrepreneurial, so we got a paper route. We would deliver papers. Now in those days when you delivered papers, if you didn’t get a complaint from a customer, you would get a movie ticket from the boss so that you could go to the movies that week. My brother and I went to lots of movies because we delivered the papers not only to the apartment. We rang the doorbell, ran upstairs, delivered it to them by hand. The satisfied customers gave us tips. We were doing well, mostly due to my brother’s entrepreneurship.
But I was robbed at one point. We had to collect money from the subscribers, and one time I came down with three teenagers in the apartment lobby. They knew I had just collected money, and they robbed me at knifepoint. After that incident, my parents felt it was unsafe to continue to live in Chicago, so that’s when we moved to West Lafayette, Indiana. My father took a position at Purdue University.
Being malnourished Asians, you know, we were small for our age, so we were always being bullied by other people. The other thing I remember is that the black kids stood up for us. Especially this one big black guy, he wouldn’t stand for the other kids bullying us. He always stood in the middle to protect us. I remember those kinds of things, all right? They happened and they seemed like small acts of kindness, but you remember them because people didn’t have to do that, yet they did the decent thing when they had a choice.
When did you start to get interested in science yourself, Frank?
I remember the exact moment. There was an exhibition that my parents took us to. Now Chicago has great museums, among them, a great Museum of Science and Industry. I think this exhibition was some kind of joint venture between the Museum of Science and Industry and the Fine Arts Museum of Chicago. They had an exhibition on Leonardo da Vinci. We went there and saw this show. I like to draw. Here was this guy who could draw much better than me, who could sculpt, who could build flying machines, who made detailed drawings of human anatomy. I mean, he was the archetypical Renaissance man, right? So, I thought, “Wow! If you’re a scientist, you can do all these things, or you can try to do all these things. This is something I want to do.” I’ve always liked since then to draw. I do believe that illustrations, good figures are a very important part of scientific presentation.
But in Chicago schools, that was a drawback. The schools weren’t that good. They were overcrowded, and classes went so slowly that it was always kind of boring. I wanted to skip grades, but my mother wouldn’t let me. Finally, she let me skip a grade, which was seventh grade, so I skipped seventh grade when we moved to Purdue. Then in high school I skipped my last year, so I entered MIT at the age of sixteen, which I would have done if I had had a normal academic career starting at four (laughter). But instead I had all these ups and downs.
Frank, was it physics specifically that you knew you wanted to pursue at MIT?
I liked physics in high school. My best teacher was actually a math teacher, and I was probably better at chemistry than I was at physics. Biology didn’t interest me at all for the following reason. I was a good student in biology, but being liked by teachers has its downsides, as I noted earlier. The biology teacher wanted me to help in experiments, so one day we had to dissect chicks. He calls me into the back room and said, “Frank, we’ve got to dissect chicks today.” I said, “Okay. I think I can manage that.” He said, “No, I want you to help me kill the chicks.” So, I had to hold the chicks while he took a tumbler and squashed it on their necks, and we killed enough chicks for all his classes. Oh, that turned me off biology! I actually took my SATs in chemistry to go to MIT because I felt more confident in chemistry. Physics I was good at. But it wasn’t what I felt then was my best subject.
What were your initial impressions of MIT when you first arrived?
I didn’t like it. Too homogeneous. I always say I went to MIT for college and I went to Harvard for graduate school, I should have reversed it, if Harvard would have me. I’d never even thought about Harvard as an undergraduate school. The reason is because at Harvard, you get exposed to more, right? MIT had a good humanities department, a surprisingly good humanities department, but I wasn’t really interested in humanities. I liked reading because that’s been my one lifelong love, and I could read really fast. I took speed reading classes, so I could read 2,000 words a minute when I entered MIT. So, I’d go through books like crazy, which helped during exams when you had to cram.
MIT had a good humanities department, so I read a lot of things that you should read as part of a liberal education. The humanities at MIT, quite honestly, is not one of the high prestige departments, right? But I read Thucydides’ Peloponnesian Wars. I read Malthus’s An Essay on the Principles of Population. I read Origin of Species by Darwin, etc., so that was good. It wasn’t taught in the way that they would have been taught, let’s say, at Harvard or at liberal arts schools with true liberal arts programs. The part I especially didn’t like was that the student body was too homogeneous.
In my dorm, the biggest contingent of MIT students in my class was from the Bronx High School of Science (laughter). They’re my friends to this day. But you know, there wasn’t much variety, so I’m afraid I wasn’t a very good student at MIT because of that. My preparation was good, and I could coast from my preparation the first year. The second year was a disaster, because I started skipping classes and cramming at the last minute. It was terrible, but there’s always some good in the bad. The good that came out of that experience was by not going to classes, I learned how to learn for myself.
I used to tell that to students at Tsing Hua. I said, “You come to college. The purpose is not to take classes.” In Taiwan, these kids would take ten classes per term. This is nuts! I said, “You don’t learn anything that way. You learn how to take exams, but that’s not the purpose of an education. What is the purpose of a college education? So, you can learn the rest of your life by yourself. You never stop learning. Once you get out of college, you’re not going to have teachers, so in college you have to learn how to learn.” That’s the most valuable lesson that I learned in my sophomore and junior years at MIT.
Frank, was it a professor or a class that compelled you to switch and major in physics?
Oh, I decided to major in physics right from the start because I always liked physics better than chemistry. What really got me interested was an astrophysics course. In physics, the discoveries are made when people go very deep to find new results. So, people start getting specialized relatively early in their lives. I didn’t like that.
In astrophysics, on the other hand, the problems are all very old. Stars were studied thousands of years ago; they’re still being studied today. Up to Einstein’s time in school, we didn’t really know about galaxies; and we didn’t know about the universe, but they’ve been around for billions of years, and we’ll always be interested in them. These were very old problems, yet they hadn’t been solved, and when they do become solved, there are still more interesting things to learn about these subjects. We’ll never stop studying the sun. We’ll never stop studying the stars. We’ll never stop studying galaxies or the universe, so I liked the aspect that it was an old subject where you could participate and be part of a long chain of learning. I am still fascinated by that aspect about astronomy.
Frank, who were some of the luminary professors that stand out in your memory in the physics department at MIT?
Well, they were all great, the best teachers. We didn’t really interact until our senior thesis with professors on a research problem. Of course, I knew about famous physics professors like Victor Weisskopf, who was probably the most famous at MIT at that time. We knew about Norbert Wiener in cybernetics, but the best teachers were people like George Clark and Walter Lewin (who were, perhaps coincidentally, astrophysicists). Anyway, the best teachers taught freshman, sophomore physics, sometimes junior physics. Those were the best teachers, but they didn’t make the same impression on me as my high school teachers, maybe because I didn’t go to many of their classes.
The person that affected me the most at MIT was the person I did my senior thesis with, who was C. C. Lin. I got lucky because I went to work for him as a summer student and he said, “Oh, I have this problem that Leon Mestel,” who was an astrophysicist from England who was visiting then, “is interested in solving, but I don’t think it can be solved analytically. It has to be solved by numerical methods, so I want you to solve this by numerical techniques.” So instead of crunching away on a desk calculator, I decided it would be better to take a course using a computer. At that point computers were being used in universities, and MIT had one of the early IBM computers. Those were things that you used to program by punching holes in cardboard cards. I learned how to program in Fortran and wrote a paper (Lin, Mestel, and Shu 1964) which is still cited today on gravitational collapse.
I did well enough on that project that Lin said, “Well, I have another problem I’m interested in, which is the spiral structure of galaxies. I’d like you to continue to help doing numerical calculations for that problem. First, take this course from Woltjer,” who was visiting from Leiden Observatory at that time. He was teaching a course on galactic structures. I took this course, and I liked it. I wished it had more mathematics in it and had more theory, but the empirical methods used to deduce that our Galaxy rotated differentially, how large it was, and how many stars it contained, were spellbinding. Anyway, working with C. C. Lin on what would become my senior thesis project on density wave theory in spiral structure galaxies really hooked me on astrophysics.
Was anybody using the term cosmology when you were an undergraduate, or that was too far afield?
Ah, cosmology. Cosmology was a hot subject which was considered by physicists to be too speculative at that time. And it was awfully speculative in its early days. For some reason I never worked in cosmology. Maybe it was part of this upbringing as a Chinese American to do safer things, which involved objective judgment, that was not so subjective in matters of taste. In those days, we didn’t even know whether steady state theory was right or some kind of big bang. The exciting stuff about the cosmic microwave background (CMB), that came later with Penzias and Wilson in 1965.
I only became interested in cosmology as a spectator because I wrote textbooks, and you couldn’t write textbooks in the eighties without covering cosmology. I liked the mathematics associated with cosmology, general relativity, etc., but the physical aspects of cosmology, now that’s what really broke the ice, so to speak, what really got all the things you could learn from about the early universe from the CMB and its fluctuations. But I had a classmate at Harvard, where I went to graduate school, who worked on such issues right from the beginning. Joe Silk was one of the pioneers of modern cosmology after the discovery of the CMB.
Later, I chaired the selection committee for the Shaw Prize. At that point it was- still is today, probably the highest prize given specifically for astronomy. We decided to award the first prize to Jim Peebles because of all that work he did in cosmology. So yes, I had to learn it to be able to make those kinds of judgments in an intelligent fashion, as well as teach it in undergraduate classes, etc.
Hawking’s discovery of Hawking radiation, I remember covering that in my classroom lectures because the connection with thermodynamics intrigued me, but I was not working in it. I used to give lectures to freshmen who took my class at Berkeley, and the TAs didn’t like it. First of all, they didn’t know the stuff (laughter). And here I was teaching it to the introductory astronomy class, but they learned to like it, you know? But you have to find ways to convey these ideas in a semi-intelligible way. I considered myself a good lecturer, but I was never a great lecturer. I would characterize myself as loved by the top third of the class, tolerated by the middle third, and hated by the bottom third (laughter). Whereas Alex Filippenko- I don’t know if you know Alex.
He’s a wonderful, wonderful teacher. I was responsible for hiring Alex at Berkeley. I can tell you that story some other time. But Alex, the students, from top to bottom, loved him! I would teach Astro ten on Tuesday/Thursdays and Alex would teach Monday/Wednesday/Friday. My TAs would say to me, “You ought to go to one of Alex’s lectures,” so I did, and I said “Wow, this guy is really good!” but a total ham, you know? (laughter) He would do things that I would be too embarrassed to do.
I remember the lecture I went to was on atomic physics, on which I considered myself reasonably well educated. I had written a textbook on it. Alex would illustrate the concept of absorption, emission, and stimulated emission and would do this by throwing and receiving colored balls. He would stand on a step and he would throw the colored ball into the audience of students. If it was a blue ball, he’d jump down two steps, and then if he caught a red ball, he would jump up one step, okay? (laughter) This drove them crazy! I could never see myself doing that kind of stunt, I have much too much inhibition to do it, but I could see this was what the students wanted.
Alex would get ratings that were just out of this world. Now on of a scale of one to seven, I might average 5.5, 5.8. Alex would be 6.5, 7! I mean he was just outstanding. I’ve never seen that kind of response. Of course, Alex is famous. You know, he was voted best professor at Berkeley for five years- best professor, period, at Berkeley, for five years in a row, and then the sixth year he was voted best professor in the United States! (laughter)
I always loved teaching. One of my proudest achievements was to convince Alex to stay at Berkeley instead of going to Caltech. It was hard because they offered him twice his salary, five times the support, and ten times the telescope time, right? How do you convince a guy like that that he should stay at Berkeley, which didn’t even have a position at the time for him?
So, I went to Alex and I said, “Alex, I know you’ve been given this offer of a faculty position at Caltech. I’d like you to stay at Berkeley,” and he says, “Well, what can you offer?” I said, “Well, we don’t have a position today, but if you stay, we will get you appointed as a lecturer and then we will immediately apply for a tenure-track position,” I was chairman at the time. “I know you love teaching. At Berkeley you will be recognized for that teaching. At Caltech they could care less” (laughter). I don’t know if that’s true, that’s my impression. I said, “Caltech students are so smart. It doesn’t matter who teaches them. They’re going to learn the material, you know, good teaching, bad teaching, it doesn’t matter.” He said, “Well, Frank, if you can deliver on what you promise, I’ll stay,” and he stayed, and he was rewarded for his outstanding teaching. I don’t think he would ever give that up.
What advice did you get about graduate school: programs to apply to, people to work with?
Well, I went to graduate school in an astronomy department which was at Harvard, and astronomy is basically not a theoretical subject. It needs theoreticians, but not in the way that physics (or some other fields) needs theoreticians. Theoreticians in astronomy are often people who help interpret data. That’s regarded as, by and large, the predominant work of theoreticians, so from that point of view, it was not a good choice for me because I didn’t want to interpret other people’s data. I don’t mind looking at their data. I want to see their data, but I wanted to form my own ideas about the implications of the data, right, and not just support some ideas of the person who took the data or did the observations. So that part of it I didn’t like about being in astrophysics, but fortunately, Harvard is a pretty broad-minded place.
In my class, we had a lot of good students and we all went our own ways and they let us. They gave us the freedom. Harvard is rich. They don’t mind paying you while you pursue your own interests, so it worked out. My class had Joe Taylor, who won the Nobel Prize for pulsars, Joe Silk, who went on to do great things in cosmology. So, we really all did very different things.
What was the process of finding a graduate advisor, somebody to mentor you for your thesis research?
I had a formal advisor, Max Krook, who let me work on what I wanted, and I wanted at that time to finish up the work on density wave theory, so he let me work with Lin on this problem. I talked to Max about mathematical issues and the like. He was a wonderful man. I don’t know if you know Max Krook, but there’s a famous equation in kinetic theory called the Krook equation. That’s Max Krook. In fact, one thing I learned from Max was kinetic theory, which helped me a lot with nuclear reactors, later in my career.
How did you go about developing your thesis research?
You know, my thesis work was very controversial. We had this theory, which was incomplete, called the density wave theory of spiral structure. Everybody thinks it’s right today, but not many people thought it was right in the beginning (laughter). It was Lin’s tenaciousness that led him, despite being a theorist, to that kind of situation where he didn’t quite know what to do, except take sort of a middle path between theory and observations and just postulate: “We see this phenomenon. Therefore, it must work.” We called this approach the hypothesis of quasi-stationary spiral structure, which was enormously controversial: that density waves are the reason behind spiral structure, and ask what are the consequences of this assumption?
Since spiral galaxies are the most common kind of galaxy and almost all disk galaxies have spiral structures, the hypothesis implies that spiral structure must be a long-lived phenomenon. These galaxies are tens of billions of years old, and yet if spiral arms were material structures, their differential rotation would add a turn every one hundred million years. Their shapes as spirals would then only last less than a percent of their lifetimes. So, we postulated the spiral structure must arise as a quasi-stationary wave phenomenon, and we should calculate the implications. That’s what we did. I helped Lin work out what’s called the first and second approximation to that approach. The second order of approximation, which contains a lot of the physics, was my PhD thesis work.
This approach became enormously unpopular to the point where the best theorists in the field, real astronomers, wrote anti-spiral theorems that claimed it was impossible to have spiral structure of this form. Who were Lin, who was not an astrophysicist, and Frank Shu, to dispute this? Lin had the fortitude to continue, and as we worked out the observation of consequence, boom, boom, boom, it began to fall in line.
Lin had another student, Bill Roberts and a postdoc, Yuan Chi, both good friends of mine, who worked out nonlinear aspects of the theory that involved shockwaves and compression of the interstellar medium. This compression led to a prediction. At that time in Holland, they were just building the first radio synthesis telescopes. Radio waves allow you to penetrate all the dust that’s in galaxies that hides what’s going on. With radio aperture synthesis, you could take pictures of a spiral galaxy, and the first picture they took showed basically what Roberts and Yuan had predicted: that the spiral arms should appear bright in synchrotron emission. That picture made the front page of the New York Times! (laughter) That was a bold prediction, which of course other people tried to knock down and have other explanations for, but it’s today still accepted as correct. But today we still don’t know what is the basic driver. We have ideas. We think it’s a growing, normal mode of the system. The system is weakly unstable to producing spirals, and over billions of years, these things will come into being from random noise More people accept that hypothesis today.
Frank, what were some of the advances in observation that may have been relevant for your thesis research?
Well, I wrote a whole review paper on that recently for Annual Reviews, which I sent to you. Just to tweak some of our former antagonists, I titled it “Six Decades of Density Wave Theory” (laughter). I didn’t knock anybody explicitly in that review article, but basically it describes many of the things we discussed earlier.
One of the big puzzles was star formation, and as I mentioned, I became interested in star formation because of the work on galactic spiral structure. In optical wavelengths, what marks the spiral structure is the massive OB stars, which are short-lived and are born in spiral arms. They delineate spiral arms when we take a visual, blue, or ultraviolet photograph. So, OB stars always reside at the crest of the wave. How can that be? They’re material things, so shouldn’t they wrap up? Well, no, because they only live ten million years. It takes one hundred million years to wrap material arms up, so they must be constantly being born there, die, and explode as supernovae before they can get out. The situation is sort of like if you look at waves on the ocean running ashore to a beach. You see whitecaps. Always at the crest of the wave are the whitecaps. Those are air bubbles. Air bubbles are material particles; they’re not waves. How do air bubbles sit on the crest of a wave? Well, it’s because the crest of the wave breaks, and where it breaks is where the air bubbles are formed. Then the air bubbles pop and disappear before they get too far from the crest of the wave.
There are all sorts of predictions that follow from such an insight. First of all, you should see the aging of the OB stars. As OB stars age, they turn from blue to red, so there is a very clear progression that you should see. It doesn’t even require much calculation to see the prediction, which should be in one sense if you’re going faster than the wave, in another sense you’re going slower than the wave. Both happen in a single galaxy. So that was the prediction, right? You should see a color gradient. That gradient was claimed not to be seen!
I would teach this conundrum in graduate classes at Berkeley and I would tell the students, “This is a big puzzle. We should see it, yet everybody is saying you don’t see it.” One of the students in the class, a woman named Rosa Gonzales- now she has a whole string of names because she got married, but anyway it’s just one person- took this up seriously by working with James Graham, an infrared instrumentalist on the faculty at Berkeley. They showed that other people were being fooled.
When you look at a picture of a spiral galaxy and you want to see the OB stars, they always create these giant ionized regions of plasmas around them. So, people were looking at these giant H II regions and taking their colors. Rosa and James said, “No, no, no. That’s wrong. When you take pictures of H II regions, you don’t see the colors of the star. You see the color of the plasma. It’s like looking at a fluorescent bulb. You’re not looking at the bulb itself; you’re looking at the emitted fluorescence. That fluorescence dominates, so you don’t see any color change because all H II regions have essentially the same emission lines!” (laughter) “You should do the opposite. You should look at where there are no O stars. Look for where are only B stars, okay? B stars create much weaker H II regions, so you can see the star colors. Don’t look at the brightest H II regions; look at the faint ones!” That’s completely counter-intuitive advice, right? I mean, it takes that kind of reasoning by somebody who doesn’t know better to do it. Students don’t know better. That’s why students are so important in science. They don’t know standard wisdom, so they can think out of the box (laughter).
So, Rosa went ahead, practiced what she preached in one galaxy, and found the predicted color gradient. Nobody paid any attention to that paper—one case, right? So, she went back to Mexico. She taught her students. They did nineteen cases: six were ambiguous, thirteen all showed it. Not only did they show the presence of color gradients, they showed the reversal where the wave speed crosses being slower to faster. So that resolved the controversy.
I tell this story in part as an illustration that it’s worthwhile to teach things which aren’t fixed knowledge. Even if you don’t know the answer yourself, somebody in the audience may make that breakthrough. In this case, it happened to be a graduate student. Not the professor James Graham, he didn’t sit in on my class, okay? (laugher) I don’t think he was aware that there was this problem. She convinced him, and he was astute enough to let her pursue the work as her PhD thesis. She convinced him, she did the first case, and she followed up years later. Now everybody believes it, including the people who were not finding color gradients.
Who was on your thesis committee?
That’s an interesting question: Dave Layzer, who was one of the prime theorists, Chuck Whitney, who was at Harvard at the time, and another guy. Whose name escapes me right now. I- anyway, one theorist, another theorist who also does observations, and another observer.
At Harvard, you had to give a defense, so I gave a presentation, answered their questions. Then as I was about to leave the room, Chuck Whitney asked, “Frank, what is the rotation period of Jupiter?” Nothing to do with my thesis, right? So, I said, “I don’t know.” He said, “Well, can you guess?” I said, “Well, it’s a big planet. It must be kind of slow” (laughter).
They decided I needed to do observations, so I hooked up with the observer guy and said, “Do you have a suitable project?” He said, “Well, no, but I have a good instrument. It’s a scanning Fabry-Pérot spectroscope, and it has very high spectral resolution.” He used it to study the atmosphere of Venus. He added, “But you’re not interested in planetary atmospheres,” judging from my response about Jupiter, “so I don’t know what you can do with it. But you’re welcome to borrow this instrument if you like” (laughter).
So, then I looked up what are the interesting problems in astrophysics requiring ultra-high-resolution spectroscopy, and I found one that seemed very interesting to me, which was the fate of lithium in stars. Now lithium has two isotopes, this is very important for molten salt reactors, by the way, but this is where I got interested in lithium-7Li, which is the most common isotope, and 6Li.
Both isotopes of lithium are easily destroyed by nuclear burning in stars. Usually you have to get to the core to do thermonuclear burning. Lithium is so easy to destroy that it can burn at the bottom of the outer convection zone in stars like the sun. The sun is old and has burned all its 6Li, and most of its 7Li. But in young stars, maybe you could use the difference in destruction rates to date their ages. The expert on this topic was George Herbig, then at UC Santa Cruz. I don’t know if you know George Herbig. He’s very famous for his work on Herbig-Haro objects.
I didn’t know George at the time. I later got to know him well. So, I wrote George a letter and said, “I see you’re working on this problem. I would like to directly attack the question of whether there’s 6Li in T Tauri stars,” on which he is a world expert, “because I have access to this instrument.” He not only wrote back, he gave me a list of specific objects I should look at with finding charts of how to find them in a telescope.
Now George had this reputation of being a bit of a curmudgeon. I never felt that way about George. He liked to argue with people and was a no-nonsense guy, but if you asked him a serious question, he would give you a serious answer and take the time to do it well.
So, I spent five, six months doing this project. Of course, I failed to get a positive detection (laughter). It was not possible to detect such a weak signal. There would be a 7Li line which I could see, but I was trying to see a little bump on the shoulder which would be the 6Li. The instrument and telescope didn’t have enough sensitivity for that. To this day, with all the improvement in instrumentation and bigger telescopes, nobody has successfully done this experiment. But it was enough to have tried. Plus, I invented some peripheral pieces of equipment to improve the instrument itself, so I managed to pass the requirement, but my thesis got delayed for more than half a year. They were right to insist that I get some observational experience. Buy maybe my reaction is another indicator of the Asian American acceptance of authority that many Americans would have rejected as an unnecessary imposition.
Americans would say, “Look, I’m done with my thesis. Why are you holding me up? I’ve got people waiting for me for a job! What is this?” (laughter)
Frank, on that note, what were those opportunities? What was available to you after you defended?
When I defended, I used the Harvard-Smithsonian Agassiz telescope. That was not big enough. Later, when I came to Berkeley, the Lick telescopes were available to me. In 1973, I was in transition between Stony Brook, where I got my first job after Harvard, and going to Berkeley. I spent that transition summer in Holland because they were doing this synthesis array imaging of spiral structure, and they wanted me to go there as a faculty member. I said, “No, but I can spend the summer there.” I spent that summer. I really liked the Dutch environment. To this day I like going to Holland. So, you know, I was lucky to have had multiple employment opportunities.
Then also, because Lin had this attitude that it was important to work with observers, I got to know a lot of the world’s great observers. Bart Bok knew me as a graduate student. I remember when he first met me. He said, “Oh, you’re Frank Shu! I thought you were an old man!” (laughter) Anyway, I got to know Bart Bok. I got to know Jan Oort and Mort Roberts and that helped a lot because I could talk to them. I always found that it was important to talk to observers in their own language. When you say resources, partly it’s telescopic resources, but even more important it’s human contacts, and I was very lucky that I got to know powerful intellects early on.
So, what did you do next? What was your first job after Harvard?
Well, I was married, and I had a wife to support, to put through college. She was in her last year at Wellesley. So, I went to Stony Brook. We lived in Manhattan. I used to commute from Manhattan to Stony Brook. That was a nightmare. I was at Stony Brook for five years, but I was gone for almost a year on sabbatical. They gave me a lot of freedom.
At that time, I was interested in what’s called the two-phase interstellar medium, which I wanted to couple to density wave theory to see what it could teach us about star formation, which was more and more becoming my predominant interest. There were two experts on the theory of the two-phase interstellar medium. One was Lyman Spitzer at Princeton. The other was George Field at Berkeley. I asked George if I could visit him at Berkeley, and he said, “Of course.” He knew what I was interested in and he said, “I’ll have my graduate student work with you on this.” It was Don Goldsmith. I don’t know if you know Don Goldsmith. Later I helped bring Don Goldsmith to Stony Brook. Don’s an interesting character, a very smart guy.
Anyway, I came to Berkeley and about halfway through, George says, “Frank, I’d like to have dinner with you.” I said, “Sure.” So, we went to a Chinese restaurant for dinner. He said, “Frank, I don’t want you to tell anybody else, but I’ve got an offer from Harvard and I think I’m going to go there. They want me to be the director of the observatory, chair the department, etc. I think I’ll go there, but I wanted to alert you that I’ll be gone.” Well, sure enough, he left, and his position became open (laughter). Then Stu Boyer called- do you know Stu Boyer?
Well, you know what Stu Boyer is like (laughter). So here I am in Long Island. three a.m. the phone rings. It’s Stu Boyer. He opens with, “Frank, we have a position at Berkeley, George Field’s position. We would like you to apply for it.” I said, “Of course I’ll apply, but I’m curious. Why did you call me about this?” He said, “Well, you gave this colloquium about spiral density wave theory in the department, and you said that we live in an inter-arm region, not in one of the arms like everybody tells me here. You know we live in an inter-arm region. That means it's very rarified gas all around us, right?” I said, “Yes.” “That means I can see EUV rays, right?” (EUV, extreme ultraviolet.) I said, “Well, I don’t know about that, but you have a much better chance.” “Well, that’s why I want you to come here” (laughter). Stu always had an angle (laughter). Later, when Voyager flew beyond the heliosphere, it found that we indeed live in a very low-density part of the interstellar medium, not the typical or the peak region. There are these unknown chance coincidences that shape one’s life. I came to Berkeley and I loved it. I don’t know why I ever left (laughter).
What was so exciting when you got to Berkeley? What was happening at that point?
The most exciting things were the variety of faculty members and the students. The group that influenced me most probably was the group that was working on millimeter wave interferometry. Now millimeter waves is the proper way to study star formation. Interferometry is a way to get images, right? Up to then millimeter-wave radio astronomy had all been done with big telescopes involving spectroscopy or photometry, detecting intensity, but not with pictures. With millimeter wave interferometry, pictures became possible of the gas and dust that makes stars, so I interacted most with Jack Welch in the radio astronomy lab and Charlie Townes in physics. In fact, Charlie and I used to have lunch once a day of the week because he thought I was a good source of information about astronomy. Of course, if you have a chance to have lunch with Charlie Townes, you do it! One day- I’m sorry. I’m going off track.
One day I’m getting ready to go to lunch with Charlie Townes when the phone rings. Somebody had something important to tell me, so I’m on the phone for five minutes and then I’m about ready to go out the door, and the phone rings again. So, I dashed to the phone and picked it up. He says, “Frank?” I said, “Yes.” “This is Charlie. Where are you?” (laughter) Five minutes late and he wanted to have lunch! That was the way Charlie was. I mean, he was a wonderful person, a real pleasure to talk to.
Anyway, I got more and more involved with the radio astronomy group, and I tried to pay them back when the NSF came to review the Hat Creek site. Jack would say, “Well, Frank, I’d like you to come up and help us with our presentation with the NSF.” I said, “Jack, I’d be happy to go to Hat Creek with you, but isn’t it a four-hour drive up there?” He said, “No, it’s one hour.” “It’s just one hour?” He said, “Well, I fly there.” I said, “Oh!” He said, “I’ll take you on my plane.” I said, “Okay, Jack, that’s great. Let’s go.”
One of my students at that time, Susana Lizano, came the next day into my office and said, “Frank, I hear you’re going up to Hat Creek with Jack on his plane.” I said, “Yes.” She said, “Didn’t you hear about his accident?” I said, “Well, yeah, I heard he had to do an emergency landing in the mountains, but he came out of it okay.” She said, “No, this is very dangerous. You shouldn’t go.” I said, “Well, let me think about it.”
The next day she was in my office. “Frank, have you thought about it?” I said, “Yes.” “What are you going to do?” I said, “I’m going to go.” She said, “What? You’re going? Didn’t you hear what I told you?” I said, “Yes, but Jack is the coolest customer I know. If we get into problems, he’ll be able to land safely.” She said, “No, Frank. You shouldn’t go.” She was after me for the whole week.
The next week, I’m about ready to go. She comes into my office and says, “Frank, are you determined to go?” I said, “Yes.” She said, “Well, here’s my thesis. Can you sign it, please?” (laughter)
Susana is a wonderful person. I don’t know if you know her. She’s now the president of the Mexican Academy of Sciences.
That’s what I mean by having good students at Berkeley.
Frank, tell me about the ideas that coalesced with star formation that led to the so-called inside-out collapse model.
Well, at that time I was actually working on interacting binary stars. Together with Steve Lubow, I actually wrote an Annual Reviews article on the subject. We did some good things, good enough to have them invite us to write an annual reviews article. But working on interacting binary stars was generally a terrible experience. The people working in it sniped at competitors. I hadn’t gotten that kind of sniping since I was a graduate student. The one thing that bothers me about the Brits, apart from my family history, is that the Brits can be awfully rude. There’s this smart-ass attitude about a British education that makes putting people down the best thing that you can do, They would write papers that would have language that you wouldn’t direct to a five-year-old, much less a colleague, right?
Anyway, I thought it was a terrible subject because they would write stuff like that. So, I was complaining about this to Bart Bok when I visited Arizona and Bart says, “Frank, you ought to work on star formation.” When I talked to Steve Strom, Steve Strom said, “You ought to work on star formation.” I replied, “Yeah, I am interested in star formation,” and he said, “No. I mean really forming stars, not the interstellar medium kind of stuff you’re doing. Forming stars.” I said, “Okay. I’ll look for a problem on forming stars.”
So, I looked up the literature and read some papers. That’s an advantage I have, I can read papers very quickly. I found a paper which I thought was promising on collapse of stars. The world expert at that time was Richard Larson at Yale. I knew about his work. So, I said, “Oh, I think I can extend this,” and that’s when I wrote my paper on, inside-out collapse, which probably contains my most famous equation.
I’ll give you the equation, which you’ll appreciate that I can express it in five seconds: ? = a3/G. That’s a mass accretion rate that falls to build a star when the sound speed is a and G is Newton’s gravitational constant. Now, that’s an interesting equation, right? It’s not quite in the class of E = mc2, but it’s almost equally succinct: ? = a3/G. Now actually, it’s not 1 times a3 / G, it’s 0.975, but who’s going to in astrophysics argue about 0.975 versus 1? Apart from our annual reviews article on star formation, it’s probably my most frequently cited paper in astrophysics. But the name doesn’t come from me. Inside-out collapse is a great name, right?
It came from Susana Lizano! I called it something else, but she, for whom English is not her native language, came up with the catchy name. In terms of all-around feel for how people will react, she has an unsurpassed ability. Everybody who knows her knows this quality about her. So, she was the one who coined inside-out collapse. When Shu, Adams, and Lizano, drew our four-stage cartoon in our Annual Reviews paper, inside-out collapse was the second stage.
What did you work on next after star formation?
Well, I returned to work on density wave theory because density waves were found to be important in planetary rings. The rings of Saturn differ by twelve orders of magnitude in linear scale compared to a spiral galaxy, but it’s the same basic physics that goes on, which is a wonderful empirical demonstration that gravity has no scale. It works on galaxies. It works on planetary rings. I got into it, by happenstance, because Peter Goldreich, who is one of my heroes- I don’t know if you know Peter.
Peter was the second guy that we gave the Shaw Prize to because we thought he was the greatest theorist of my generation. Peter is capable of doing anything. Anyway, he and Scott Tremaine, both of them are really smart, wrote this paper on the Cassini division in Saturn’s rings. There’s a famous divide between the two main rings, A and B. It’s called the Cassini division, and they claimed that this division was caused by the clearing out of the particles that would have been in the ring by density waves resonantly excited by the moon Mimas. Now this has a wonderful history which I’m sorry to bother you with because it’s another digression.
The person who really made a big advance on Saturn’s rings historically was Huygens. Huygens was a famous figure in the history of science, right? Huygens didn’t discover the rings; Galileo discovered the rings, but he thought they were ears to a planet. Galileo was completely puzzled because later the ears disappear? When they later reappeared, he was even more puzzled. Huygens said, “No, no, no. They’re rings around the planet, and as the planet orbits around the sun, sometimes it goes edge-on, so they seem to disappear.” They disappeared because they went edge-on, and then later you see the bottom side. So that was a great breakthrough.
Maxwell (Maxwell’s equations) came later and said, “No, no, no. These are not rings of matter as Laplace thought they were. They don’t link physically all the way around like a bracelet. They’re individual particles, pieces of rock, or pebbles, or whatever”- ice we know them to be today- “that independently orbit around Saturn.”
So, the subject has this great illustrious history, and then Goldreich and Tremaine propose the main divide that you see is due to density waves resonantly excited at a place where the ring particles orbit twice around Saturn for each time that Mimas orbits once. My then graduate student Jack Lissauer and I were aware of their interesting idea, and we read their paper carefully. Anyway, Jeff Cuzzi, who was working at JPL on the Voyager missions to Saturn, says, “Frank, do you know this paper on Cassini Division by Goldreich and Tremaine?” I said, “Yes.” He asked, “Is the Cassini Division empty like they say?” I said, “Well, I don’t think so, but why do you ask?” He said, “Well, because we’re thinking of flying Voyager through the gap the rings to come out the other side and look backwards toward the Earth.” I said, “Well, I think their theory is right, but it’s incomplete. They explain the outer edge of B ring, but they don’t say why the inner edge of the A ring doesn’t march in and fill in the gap. So, there might be material there, but I don’t really know. If I were you, I wouldn’t fly through the gap with Voyager 1. I’d fly over it, take a picture, see if it’s empty or not, and then if it’s empty, fly Voyager 2 through the gap.”
I don’t know that they listened to me, but that’s what they did. It’s a good thing they didn’t try to thread through Cassini’s Division because it’s not completely empty! (laughter) There are some empty bands, but most of it has stuff in it. Jack, Jeff, and I even wrote a paper on why there is stuff in it and why it’s banded as seen in the Voyager images.
All these ideas led to the notion of planet migration because we and others thought, “Well, if Mimas is holding back the B ring by transferring negative angular momentum to it, that means Mimas itself is migrating outwards in back reaction. In fact, Mimas won’t always be there. We see all these small moons between the A ring and Mimas. Maybe they were all born in the A ring and are now leaving the rings, hatching chicks that leave the flock.”
This notion became a topic that was widely discussed among the theorists working on planet formation in those days. I even wrote a paper saying that Jupiter may not have always been always where it it is today, and there were others, such as John Papaloizou and Doug Lin, who talked about planet migration even earlier. Well, the observers didn’t pay any attention to these ruminations. They were just theoretical speculations.
One day Geoff Marcy walks into my office and says, “Frank, the French have found a Jupiter-like planet around Beta Pic. Paul Butler and I have verified the discovery.” I said, “Oh, that’s great! Wow.” He said, “Instead of being at 5 AU, it’s at 0.05 AU.” Okay. “How could it get formed there? I said, “It didn’t form there. It migrated there.” He said, “Well, how does it stay there?” Well, by then I was working on star formation and how stars empty magnetically an annular region just their outer radius, so I explained the idea of resonant forcing to Geoff Marcy. I said, “Stars invariably establish protoplanetary disks when they form, and planets born in that disk interact with the disk by resonant forcing, which slowly causes the planet to migrate inwards. But when the planet gets into the gap created magnetically by the star, the planet is safe because it can park there. It no longer interacts with the protoplanetary disk around the star, and 0.05 AU sounds about right where it can park safely.” Geoff says, “Oh, that’s a great idea! You should write it up.” I said, “I’m not interested in post-facto predictions. I’ll tell this to Doug Lin, who’s working on a general theory about this topic. He can write it up and then in the acknowledgements he can credit me for suggesting this particular idea.” Doug did write it up and did credit me, but he left out all the interesting parts of the argument! (laughter) But, nevertheless, it goes to show that unexpected connections can pop up in any subject.
To summarize, I got interested in actually forming stars because of this advice from Bart Bok and Steve Strom. I worked on the process was initiated by inside-out collapse, and how the accretion was halted in sun-like stars by magnetic interactions between the star and its surrounding accretion disk. The latter topic got me interested in why stars have bipolar outflows. You know, outflows are just the opposite of inside-out collapse, right? Why does every star that forms, the first thing that follows is that it blows stuff back out? We hardly ever see stars collapsing. You’ve got to collapse to form the star, but then it blows it back out. I had to come up with ideas for these seemingly opposed phenomena. I wasn’t happy with the existing ideas, and so it all came together. Maybe it’s only because it’s a fake association, and it’s only me that’s forcing them together, not nature. But I suspect there might be some truth to how nature solves the angular momentum barrier to simple gravitational collapse. Anyway, making these connections is very stimulating, right or wrong!
You said you were surprised you ever left Berkeley. What specifically?
Well, I loved it at Berkeley. I still love Berkeley because of the people there. I left because of a sense of restlessness in general that perhaps I’d done what I could in terms of the combination of research, teaching, and administration. The thing that really triggered it was a call, not in the middle of the night, but in the evening, from Taiwan from a friend of mine who used to be at Berkeley chemistry department. You may know him. Y. T. Lee.
Yeah. Nobelist in Chemistry. So, Y. T. Lee calls me. I knew him from Berkeley. He was a great supporter of astronomy. He had left Berkeley to go to Taiwan to become president of Academia Sinica. He calls me and he says, “Frank, Tsing Hua is looking for a new president. I would like you to apply for the job.” I replied, “That’s not on my bucket list” (laughter). “I am constitutionally averse to doing administration. I don’t like having power over people, I don’t like this kind of responsibility, and now you want me to head a university?” “Well, your father did it.” I said, “Well, you know, my father is different.” He said, “Well, I still would like you to come for an interview. Think about it, what you would do if you were to advise the search committee on a new president for Tsing Hua.” How could I refuse, right? He was so helpful in getting the Institute of Astronomy and Astrophysics started in Taiwan. It’s why Taiwan is a powerhouse today in Asian astronomy. So, I said, “Okay. Since you asked me, I’ll come, but I’ll give your committee five reasons why I’m the wrong choice.”
Frank, was the expectation that this would be an English-speaking position or a Chinese-speaking position?
You ask a wonderful question. I’ll get to it later. So, I come to the hotel where the interview is being conducted. It was probably the fanciest hotel I’ve ever stayed in. They really pulled out all the stops. Then I go to the meeting room where the search committee is based. Y. T. Lee sits up at the head of the table. Right next to him is Morris Chang. I don’t know if you know who Morris Chang is. Morris Chang is the founder and CEO of Taiwan Semiconductor Manufacturing Corporation (TSMC). They make eighty percent of the integrated circuit chips in the world, okay? Morris Chang was somebody that my father recruited back to Taiwan. That’s one of the things my father did when he was president of Tsing Hua University. They both knew my family history, right? So, he’s sitting right next to Y. T. Lee as the co-chair of this search committee (laughter). I sat down and thought, “Oh, I’m in trouble.”
So, I said, “Well, I’d like to give you five reasons why I would not be a good choice for this job,” and I gave my five reasons and after each they would both nod. They said, “Well, that’s good. Tell us, what would you look for in a position where your father used to be president?” I gave them some ideas. I told them how they needed to be more international, that it was not enough just to compete with National Taiwan University, which is considered the best university in Taiwan. They had to compete on an international level, and that Taiwan should have at least one, if not more, universities ranked among the top one hundred within a reasonable length of time, and eventually within the top twenty if it wants to survive. They said, “Oh, that’s great.” Every time I said something, they said, “Oh, that’s great.” Of course, they totally biased the rest of the committee.
So sure enough, I get offered the position. I still wouldn’t have gone, except my father died in that period. So, I had a chance to think about my father in the same situation, who did accept. Of course, he always wanted to go, but to mainland China. He never really had a deep connection with Taiwan, but as he told me later, it was his chance to help Chinese people.
I remember one conversation I had with him before he left. My mother didn’t want him to go to Taiwan. She was too used to life in the United States, so I asked my father, “Dad, why are you going to Taiwan? Mom doesn’t like it there. You have a comfortable job in Purdue, and Mom really likes it here. You have all your friends here. Why are you doing this at this stage in your life?” He was fifty-eight at the time. He said, “Frank, you and I are professors. Being a professor is a privilege because we have only one responsibility.” I said, “What’s that?” He said, “It’s to the future. The one responsibility academics have is to the future. What kind of future do Taiwan college students have? There is no high-tech industry in Taiwan. They barely moved out of the agricultural age. They have some heavy industry like steelmaking and shipbuilding, but that’s it. Anybody serious majoring in the sciences or engineering goes abroad to study and stays abroad. I’m going to go to Taiwan and give them a reason to come back.”
Well, you know, one doesn’t forget a speech like that, and so when my father passed away, I remembered what he told me. I have a responsibility. Even though I don’t have much of a history with Taiwan, nevertheless I had spent time there. And my father, in particular, had made a world of difference for Taiwan. He is universally credited as one of the two people who turned Taiwan from a manufacturing-based economy to a knowledge-based economy. In mainland China, they add another fiction. They say (or they used to say) that my father is one of the wealthiest Chinese Americans in the United States. That’s total fiction (laughter). I know what my father made. He never took a dime from any of these positions, okay? He died barely as a member of the middle class. Hardly left anything for the kids and the grandkids. My portion I just passed on to the grandkids because I don’t need it.
So anyway, I said, “I have a legacy to live up to. I owe it to my father to go back and help Taiwan” in part because they themselves have forgotten this transition that he helped to make. They give all the credit to the minister of economic affairs. He was the one that supplied the money to build the Science Park, but the park is in Hsinchu! Taiwan’s Silicon Valley is in the city where Tsing Hua is located. That’s not a coincidence! That’s because my father put it there, when he held the position of the head of the National Science Council. Everybody in Tsing Hua knows this story, but outside Tsing Hua they don’t acknowledge it. So, I thought, “Well, I’ve got to go back and remind them about this fact,” not saying it, but through my presence.
I went back and tried to help. I didn’t like it at all. It was everything I was afraid it would be. You know, when you become an administrator, your objectives change. I used to tell this to the faculty, I don’t know if they believed me. I said, “You know, the only person who should have the job that I have is the person who doesn’t want the job. That’s why you’re lucky to have me, because I can say things where I’m not afraid of the consequences. I don’t want the job, so fire me!” (laughter) So I was able to do things that other people couldn’t. To do everything that needed doing, I should have stayed longer, but after four years I had enough. Being an administrator, a good administrator, means helping others to succeed. That’s your main job, not doing research, not teaching.
I kept up both. I got scolded for it. People said, “Why are you doing research?” Because a university president shouldn’t do research, right? “Why are you teaching?” Shouldn’t I know what the students are like? As to teaching in English or in Chinese, I went there hardly speaking any Chinese. I left a Chinese speaking environment when I was six years old at a level of a six-year-old. In the United States, I used to speak in Chinese with my mother, but at the level of a six-year-old. You can’t do that at a university. I would give talks in English. I would teach in English. But I found that although people in Taiwan studied English from third grade on, they never learned English properly. They could all read English. Reading was not a problem. Listening was more of a problem, but not too bad. They could listen to lectures and grab enough of it. Speaking English was difficult, but if they asked questions in simple Chinese, we could communicate. Where they really fall down was having to write in English.
Now when I taught at Berkeley, I insisted in my classes, every class I taught, that students write a project from the term, something they found interesting. They would write it, I would read it. and I would grade both the science and the exposition, because I felt correct expression of one’s ideas is important. I’m sure you agree since you’re a writer, you’re a professional writer.
Writing in English is one of the skills you have to have if you want to be professional in international settings. The one thing that Susana Lizano didn’t do well as a student was write English. The first thing I did when I realized this, I bought her a copy of Pride and Prejudice. I said, “I want you to read this, not so that you can learn to write like Jane Austen, that’s impossible, but to see what style means. Not just writing in coherent sentences, but to write it with style so that even mundane things, day-to-day things, can still be interesting. That’s Jane Austen’s great genius, right?” So, Susana doesn’t write like Jane Austen, but she learned from her books. She came up with the phrase “inside-out collapse. Anyway, I’m digressing, as usual.
Eventually I decided I had to teach in Chinese and give talks in Chinese, so I did. But the PowerPoints were all in English so I could use the English to prompt my Chinese, so I didn’t have to think in Chinese (laughter). I got good enough at it when I was in Taiwan. I used to have dreams in Chinese, and I thought, “Well, I did pass a certain level if I can dream in Chinese.” Anyway, that’s one difficulty.
Here’s the other difficulty: citizenship. My father and I are bookends to the question of citizenship. The reason my father left Taiwan is because they insisted that in his job, he had to give up his U.S. citizenship and he told them that he stayed roughly ten years. He said, “If you had asked me this when I came, I might have done it, but now I’m near retirement. Now you ask this of me, I won’t do it. I value my American citizenship. My wife likes America,” so he left Taiwan over this issue.
Because of that, by the time they appointed me, which was when I was fifty-eight, my father’s age when he became President of Tsing Hua, but twenty-eight years later. The law had changed. You no longer had to give up your citizenship, okay? That law was changed before I became president, and you could keep your American nationality. It would be a dual citizenship, which means the following. As far as the United States is concerned, Taiwan is not a country, so I am still a naturalized citizen of the USA. As far as Taiwan is concerned, since I had resided in Taiwan for a year when I was five, I’m a Taiwan resident, so I can be a university president. I can’t be president of the country, but I can be president of a university (laughter). So, my father and I were bookends.
What did you see as your mandate as president? What were you expected to do, and what did you want to do?
Well, I hate to say it, but if you want to do anything, you’ve got to have a budget that allows you to do it. At that time, the university budget was abysmal. Tsing Hua at that time was probably a university with about 10,000 students, forty percent of whom were graduate students: 6,000 undergraduates; 4,000 graduate students. So, a place of that size, a good university in the United States, would have a budget of several hundred million dollars, if not a billion dollars. The budget at Tsing Hua at that time was probably about US$60 million, including grants- total. So, my target was to increase the budget by a factor of two. The target was to get to US$120 million in four years, and to grow from there.
Now, in Asia it is very hard to get money from private donors because there just isn’t that tradition of giving to public universities. They think that’s the government’s job. So, you have to get it out of the government. One of the things I was able to do was to help mandate in law a grants program that would give research universities a different budget from teaching universities that would be in turn because of teaching grants a different budget from vocational schools. (Tsing Hua would be, of course, one of the research universities.)
When I went to Taiwan, the idea of differential funding was slowly being pushed. I helped push it harder and we got the grants budget doubled to about US$300 million a year to be divided unevenly among twelve research universities based on submitted proposals (written in Chinese) that would be reviewed by an international panel of ethnic Chinese academics. Anyway, it was enough to meet the target that I had set for Tsing Hua, providing Tsing Hua won the competition. There would be others that came in behind first place that would get lesser amounts of money.
So, you had to write a proposal; you had to defend the proposal in an oral interview with the panel. That’s where my Chinese was put to the greatest test because I had to take questions at the interview and answer them in Chinese.
Anyway, the premier at that time, whom I saw often, said that he would double the grants budget, providing that Tsing Hua and Chiao Tung Universities, who were both based in Hsinchu, merged. Chiao Tung is engineering-oriented; Tsing Hua, science-oriented. Together, we had a chance to win the big prize, i.e., to beat National Taiwan University. But we had to get approval for the merger from the faculty senates of the two universities.
Now, merging two universities- it’s a huge problem. Even in the United States, one of the few successful cases was Case Western. Harvard and MIT never succeeded, and not from a lack of trying. It’s very tough to convince faculty, students, and alumni. A symbolic difficulty is the merged name, right? It’s worse in Chinese where names have two characters, taking one from each school would produce gibberish. You have to use all four characters: Tsing-Hua-Chiao-Tung or Chiao-Tung-Tsing-Hua? Even if you can get past the name difficulty (which we did), you have to get it through, not a Board of Directors, but the faculty senate. They have to vote.
Well, that means a lot of preparatory work. With my two VPs, we visited each academic department and college to persuade the faculty that merger was a good thing to do, and to take the same case to the Alumni Association. When the faculty senate voted, Tsing Hua overwhelmingly passed the resolution because we had done our homework. There were one hundred and six votes cast, only six dissenting votes, and those all came from the student representatives. The students never want to merge with their rivals. All faculty voted yes, we should do this.
Chiao Tung University had a different kind of president who was seen as my rival and whom I honestly didn’t like very much because of his super-aggressive way of doing things. They were always bragging there would be a problem at Tsing Hua, but non at Chiao Tung. Well, the faculty senate shot down the merger resolution, so it didn’t happen. When it came time to review the proposals, Tsing Hua came out number one, above everybody else including National Taiwan University. We were given the top-rated tanking because we were the most ambitious and we had the clearest plan of what to do.
That must have made you feel pretty good.
That did make me feel good, but still the prize slipped away. The reason it didn’t happen was that the minister of education blocked it. He went against the recommendation of the outside review committee to give the most money to Tsing Hua. We got the second-most. We got the most per capita, but that doesn’t count because Taiwan University is much bigger than us. So, we didn’t win. Anyway, we didn’t get a one hundred percent doubling; we only got eighty-six percent, and I thought, “Well, I’ve done my duty. I can leave” (laughter).
Did you expect to stay longer than four years? Was that seen as a short tenure?
When I went to Taiwan, I was prepared to stay two terms, eight years. But I couldn’t take another term (laughter). I liked doing research too much. I liked teaching and writing books. I saw other important problems.
Were you looking specifically for faculty positions, or did San Diego reach out to you out of nowhere; you weren’t expecting it?
I was going to go back to Berkeley. I had almost signed the letters when San Diego said, “Frank, we’d like you to come for a colloquium.”
Who was it at San Diego that was driving the recruitment?
Well, I’m sure the Burbidges had something in part to do with it. The person who was in the administrative position at that time was Art Wolfe. I don’t know if you know Art Wolfe.
He worked on cosmology. He was the one that said, “Frank, we’d like you to come down and give a talk.” So, I come down, sit around the table before the talk. The first thing they talked to me about was housing (laughter). I was like, “Why are they talking to me about housing?” Then they set up an appointment with the chancellor. I said, “Why are they setting up an appointment with the chancellor?” Well, I soon found out, right? They wanted me to go. I wouldn’t have gone, as much as I like San Diego, except they made me an offer I couldn’t refuse. When I went to see the chancellor, she said, “You define the job.” I said, “Well, you know, I have many international interests, so if I came to San Diego, I would like the freedom to pursue some of those interests.”
Did it include climate change? Were you already thinking about climate change?
No. I was thinking more in terms of helping Asia and Taiwan. I thought they should have better international reach. That was my idea then right from the start. The chancellor said, “Well, we’ll give you only half the official duties and one hundred percent pay.” Plus, they gave me a good startup package. I felt so embarrassed. I said, “I’ll only take half the startup package,” but I did accept the position.
It sort of worked out, but again, Taiwan failed to follow up. You know, getting land on a university campus is one of the hardest things you can do, right? Well, San Diego agreed to have a parking lot’s worth of space overlooking the Pacific Ocean for Taiwan to use if we set up an international research institute. That was my idea. I wanted a research institute where people could come on sabbatical, see what it’s like in a competitive place. San Diego is strong in the biomedical sciences. Biomedical research is an important part of Taiwan’s push, so it was a good match in addition to science and engineering. Somehow, Taiwan failed to follow up, so the offer eventually lapsed. You know, I just don’t understand people. In San Diego, when people give you part of their beautiful campus, that’s a very difficult opportunity. Anyway, it didn’t happen.
I partly blame myself. What I learned from doing administration is you have to have power. If you don’t have the position, you don’t have the power. So, I was just an interested party at that point. Taiwan wasn’t interested because I held no important title in Taiwan. There was no insider who had both the power and the responsibility. Yuan Lee at that point was not in power. In fact, Yuan Lee and I tried to do the same thing at Berkeley when I was in Taiwan. We went and visited Berkeley. Berkeley didn’t offer a spot on campus. They offered space in Richmond Field Station. I don’t know if you know where that is, but Richmond is not a desirable spot. It overlooks the Bay, but the worst part of the Bay. What you can see are the Chevron refineries (laughter). So not comparable to what UCSD offered that was very attractive. We wanted someplace on the Berkeley campus and couldn’t quite succeed getting that.
So, Frank, when did climate change enter the picture for you? When did you start thinking about that?
It was an article I wrote for Scientific American Taiwan. I used to write articles for them. Scientific American, as you know, is based in the USA, but it has branches in other parts of the world. Taiwan puts out its own issue where they not only reprint past Scientific American articles, but they publish original Scientific American articles from contributors in Taiwan.
I knew the editor. When I went to Taiwan, he was dean of life sciences at Tsing Hua, and he asked me if I would write a few articles for them. So, I did. I wrote a few on relativity. Students love relativity. I had a former student co-author, Mike Cai, who helped with the Chinese translation. Then I decided I should write one on climate change and on various alternative energies.
So, I wrote for him a long article. He was so nice about it. He devoted a whole issue to the article I wrote. It came out in December of 2008. So, the whole issue was one that I wrote for Scientific American Taiwan where I reviewed all possible sources of energy proceeding from first-principle calculations. What caused wind? How much maximum energy could you extract from wind? How much can you get from dams, from rainfall, because you have to fill the dams. What causes rain because of evaporation of water from the oceans. How much sunlight is there in total that falls on the Earth? How much can you extract from rooftop solar? How much energy can you get from waves? How much can you get from geothermal? Why is the interior of the Earth hot in the first place? How much can you get from nuclear, etc. I wrote a whole article with an appendix doing the calculations that the readers can verify for themselves, all from first principles.
I came to the conclusion that the most cost-effective way to stop climate change, by far, was nuclear fission because of the physics factors of millions advantage in nuclear energy compared to chemical energy, while chemical energy released by burning hydrocarbons had factors of millions over normal kinds of mechanical energy (wind, waves, etc.). Anyway, one by one, you can eliminate the unserious contenders, until you reach the conclusion that if you want to do nuclear fission, the thorium fuel cycle using molten salt reactors would be the best choice.
So, in December 2008 this article comes out. I’ll tell you what happened in Taiwan shortly but first let me first tell you what happened in China. In 2009, the Chinese Academy of Sciences announces that its top nuclear project is a thorium molten salt reactor. The person who proposed this is the vice president of the Chinese Academy of Sciences whose family name is Jiang. VP Jiang is the son of Jiang Zemin, the former president of China. So, this is coming right from the top, and he credits where he got this idea to American Scientist. Now the interesting thing is the Taiwan article, which was written in Chinese, is Scientific American Taiwan, but the Chinese translation is American Scientist, which is a different publication in America (laughter).
So, it was clear where he got it from, okay?
Anyway, somebody who wrote an article for American Scientist claimed it was his article that influenced Jiang. Now I find that hard to believe because why should somebody in China be reading the American Scientist in English when there’s this article that appears in Chinese at China’s doorstep?
The most interesting thing is that in Taiwan, the person who was premier at that time was a good friend of mine, C. S. Liu, a former president of Tsing Hua University, a person that my father had recruited from Canada to Tsing Hua. My father really recruited some good people when he was at Tsing Hua, and C. S. Liu had risen rapidly through the ranks.
Anyway, C. S. LIu was the premier, so I said to him, “I just wrote this article for Scientific American Taiwan. I really think Taiwan should look into using this reactor which can, among other things, solve the nuclear waste problem. It can take the current nuclear waste that you have stored in cooling pools at nuclear power plants and burn it to transition to a much cleaner fuel cycle, which is thorium.”
He asked me to go back to Taiwan to talk to him, so I went. He said, “This is great.” I said, “Well, thorium is great for molten salt technology. It’s an up-and-coming thing. Plus, you couple it to carbon- that’s another up-and-coming thing. So even if the project fails, it will introduce two new technologies to Taiwan.” He said, “I want to do it, but there’s a catch.” I said, “What’s the catch?” “That you have to come back.” (laughter) You know, I’m a sucker, so I said, “Well, I’d be happy to give advice on this problem, but coming back would be difficult.” He said, “Well, no. That’s my stipulation.” I said, “Well, you have to give me some guarantees. The last time this happened I thought I’d get a lot of support and I didn’t get the support in the end.” He said, “I’ll arrange an interview with the President of the country,” who was a man named Ma Ying-Jeou at that time. So, I go to talk to President Ma. I give a twenty-minute PowerPoint presentation. Ma responds back in perfect English and says, “I want to do it and I want you to head it” (laughter).
Now I got to know Ma well when he was Mayor of Taipei because he has a great command of English. I don’t know if you know, he was an English translator for Chang Ching-Kuo, who was the President that recruited my father to Taiwan. Ma has a Harvard education. He speaks beautiful English. The opposition party in Taiwan hated him because of his charisma and because they claimed he came from Hong Kong (laughter). Anyway, I thought, “Wow. Now I really am committed to return. If they won’t do it unless I go, well, I’ll spend some time to get it going until I get somebody else to take over.” So, I go back. I don’t know if I should tell you what happened after I returned to Taiwan.
You can take it out (laughter).
The next thing I know, the minister of science and technology (then the head of the National Science Council) calls me and says, “You know, we issued this call for proposals on molten salt reactors and you’re the top-ranked proposal, obviously, but we can’t fund it.” I said, “Why not?” He said, “Well, we had a visit from the American Institute of Taiwan (AIT),” which is the equivalent of a United States embassy. “The chair of the AIT came with copies of your PowerPoint presentation. He waved it in front of my face, and he said, ‘You cannot fund this.’”
What was the story? What was the idea?
Well, you see, if you can solve nuclear waste, you can make nuclear weapons.
The reason that this reactor is so powerful is because it makes trivial the hardest part of nuclear energy, which is what to do with the waste. If you can solve that problem, you have the same technology in principle that can cause you not to burn the plutonium, but to extract the plutonium and make bombs.
So, all of a sudden you found yourself in a national security issue.
Yeah! However, for technical reasons, the U.S. never made weapons from the thorium fuel cycle. Our team just submitted a proposal to NASA because they want to build a nuclear reactor for use on the moon and on Mars. On the moon, two weeks out of the month there’s no sunshine. There’s no wind whatsoever. On Mars there’s wind, but it’s a very rarified wind. Plus, it blows up a lot of dust. You have to have nuclear power if you’re going to send people to the moon and Mars.
So, NASA put out a request for proposals. Our group responded to it to build a nuclear reactor for the moon and Mars. You have to build one that can fit in a capsule and not kill the astronauts, number one, and number two, it can’t weigh too much because of limited payload capacity. So, you have to build a very compact reactor, a micro-reactor. You can do this with molten salt reactors. You can deliver ten kilowatts of electric power for one decade. That’s their specs. We think the thing we are proposing can be used at that ten times that level for ten decades, okay? So more than enough (laughter). These are very powerful reactors.
But they don’t allow you to make weapons. Even though the United States tried this route when they tried to build a bomb, it was a dud. Everybody knows what the easiest way to make a nuclear weapon is. Even North Korea can make a nuclear weapon! You know, any country that puts its mind to it can make a nuclear weapon if it wants to. The secret is out, you know? You’ve got to stop it in other ways.
Anyway, the AIT came and said, “You can’t do this,” so the head of the National Science Council then said, “We can’t fund this project.” I said, “We’ll change the name. First, I’m kind of miffed at this development. I’m an American citizen. If the AIT has a problem with this, they should come and at least talk with me. Second, how did they get my PowerPoint presentation, the talk I gave at Berkeley? How did they get that?! How do they feel it’s free for them to use that without permission?”
Anyway, I said to the head of the National Science Council, “If I were you, I would say to the AIT, ‘Okay, you won’t let Taiwan solve its nuclear waste problem; then don’t you have a moral obligation to take our waste, because then you can do the reprocessing.’” He said, “Oh no, I can’t say that.” I said, “Well, in that case, you should change the name of the project.” Later, I told my group. “We’ll call it the Heat Exchanger (HX) Project Let’s proceed with everything that a nuclear reactor will do except the nuclear reactions.”
If you generate energy, you have to use that energy. That’s the reason that nuclear energy is expensive. It’s not generating the energy. Generating it is cheaper than anything else by far, but you’ve got to get that heat out and then turn it into electricity or turn it into something useful. You have no advantage when you do that compared to burning coal. That’s why nuclear can’t compete today. Molten salt allows you to compete because you can have better turbines. We’ll do everything else, but we won’t do the nuclear fission reactions (except on paper). We’ll substitute chemical reactions for that part. To this day, in our group calls it, the HX Project. That’s what we do. Along the way, we discovered this charcoal-making business (which we call supertorrefaction) that allowed us to branch into the carbon negative part of our activities. So, when people squash your lemons, you can make lemonade.
Frank, did you ever get involved in fusion energy as a possible solution to climate change?
Do you want the long story or the short? I can tell you. I’ve written three textbooks. Fusion is in two of them. In the second of the two, I actually go into some detail about the instabilities of terrestrial fusion. The problem with fusion is that it’s basically an unstable confinement. In the sun it’s stable because it’s gravity that does it, but we don’t have the sun’s gravity on Earth, so we try to do it with magnetic fields. Once you do that, it becomes unstable and the instabilities present huge obstacles to making fusion a practical source of energy. Basically, you’re trying to hold down something heavy, which is a hot plasma, with something light, which is magnetic fields. It’s as if there were gravity pointing inwards, okay? The reactor (a tokamak machine) doesn’t like this setup; it wants to flip it around. That’s the fundamental instability with magnetic fusion.
Another hurdle is how to get more energy out than you put in, even if it’s just for one minute per day. You spend the rest of the day fixing your equipment so that you can do the next minute the next day. That’s not reliable power (laughter). That’s a fundamental problem! I can’t even tell you whether a resolution remains is in sight. There’s a lot of hype about breaking even. Well, so what? How do you make a reactor out of this unstable device?
Yet another obstacle is that the first generation of fusion machines uses deuterium and tritium for fuel. When you combine deuterium and tritium, you get a helium nucleus out of which is ejected a neutron. That electrically uncharged neutron is not going to be confined by the magnetic field of the tokamak. Neutrons are going to hit the walls of your tokamak and make those walls radioactive. It’s not anywhere near as bad as the radioactivity of fission products, but sooner or later you are confronted with discarding a very expensive piece of machinery.
Moreover, where does the tritium come from? Tritium doesn’t occur naturally on Earth. It has to be made! Where is tritium made? It’s made in fission reactors. Fukushima made lots of tritium. Now they lots of cooling water contaminated with tritium. What do they do with all this tritium-laced cooling water? The most sensible option is to dump it into the ocean. But this decision gives Japan a poor public image. People get all bent out of shape because tritium is a weak beta emitter. When I give my talks in auditorium, I ask, “Do you know there’s tritium in this room? If there’s a fire and the lights go out, what light remains on? The exit sign, right? What’s that powered by? It’s not powered by a chemical battery. And it’s not building electricity because that has shut off. It’s powered by tritium. When the building is on fire, the radioactivity from tritium is a small price to pay if it will save your skin. In fact, the beta particle it emits can’t even penetrate through your skin.” Well, climate change has the world on fire, so people better learn to live with minor amounts of tritium.
Unfortunately, the only tritium we have on Earth is made in fission reactors, so how is it possible to produce more energy from fusion than fission? Thus, the first generation of fusion machines is unlikely to save us from the ravages of climate change. What about the second generation, which will use deuterium and 3He as the fusion fuel? The good news that reaction products, an alpha and a proton, are both electrically charged particles, and therefore the reaction products can be confined, albeit unstably, by the fusion machine’s magnetic field. The bad news arises because the fully ionized reactant 3He has twice the positive charge as fully ionized tritium. To overcome the Coulomb barrier of the reactants, the second-generation machine must heat its reactsnt plasma to a temperature to a billion degrees Kelvin, so now your confinement problems are even worse, but your fuel is better.
Unfortunately, 3He on Earth is very rare and very expensive. There’s hardly any of it, so you can’t afford to burn it as a thermonuclear fuel. There’s 3He on the moon and Mars, accumulated by these non-magnetized bodies from the solar wind. Maybe that’s why we’re going to the moon and Mars (laughter). But it’s going to be a long time before we’re mining 3He from extra-terrestrial bodies. I don’t usually talk about it because I don’t want to discourage fusion research. I want fusion to work, but it’s not as easy as some people seem to think.
A promising idea that I sometimes think about because it's the basis of a cancer treatment known as boron neutron capture therapy (BCNT) is extracting nuclear energy from boron, specifically 10B. 10B is the light isotope of boron (11B is the heavy isotope) that has a huge capture cross-section for neutrons. When 10B captures a neutron, it fissions, emitting 7li and an alpha particle (4He) carrying lots of kinetic energy. Some so-called “cold fusion” experiments may show otherwise inexplicable energy release by this process. Boron contaminates a lot of laboratories, and free neutrons are created in our atmosphere by cosmic-ray showers. So, the extra amounts of energy released may be real, but cold fusion being the cause is probably fake.
BCNT holds a lot of promise for treating brain tumors. Brain tumors are one of the hardest cancers to treat because there is a blood-brain barrier. So, if a patient has chemotherapy for the tumor, it’s hard to get the drug into the brain. However, it’s possible to deliver boron to the brain by a substitution in glucose. The brain has a lot of metabolic activity, and growing cancer cells use a lot of glucose. Thus, if you have a way to deliver glucose, you can deliver 10B. Now you just aim a beam of neutrons going toward the tumor in the brain, and the 10B will capture most of the neutrons, fission to send out fission fragments that kill the malignant cells. Neutrons from research reactors are sufficient, and I’m happy to report that the research reactor on the Hsinchu campus of Tsing Hua participates in this promising humanitarian research.
Frank, what were the earliest ideas that ultimately led to the creation of Astron?
It was the molten salt reactor. Oak Ridge proposed it originally. Why was it never adopted by the United States? In part, it was a political decision, but in part—they never liked to admit it- it had a technical problem. Thorium by itself is not fissionable, but it can become fissionable if you feed it a neutron. So, if you have something else like 233U that gives off 2.5 neutrons on average per fission, then one can make thorium into something that’s fissionable and still have 1.5 left to run the chain reaction. You only need one, so the extra half can actually make extra fuel. That’s a breeder reactor, okay?
Now, the problem is that when thorium captures that neutron, it has to beta decay twice before it becomes fissile, something fissionable. The rate of those beta decays versus the rate of additional neutron captures lead to a competition that astrophysicists call the r-process and s-process, r for “rapid” and “s” for slow. In the r-process the neutrons come so rapidly that the target nucleus has no chance to beta-decay before it captures another neutron to become a yet heavier isotope of the same basic element. In the s-process, the neutrons come so slowly, that nucleus that just absorbed a neutron has a chance to beta decay, changing its atomic number by one and therefore becoming a different chemical element.
In a molten-salt nuclear reactor, both types of processes are going on. 232Th captures a neutron to become 233Th, which will become fissile 233Ufuel if the reactor is tuned for the s-process. However, running the reactor at low power is uneconomical, so the economics dictates that the flux of neutrons is s-process only for the first beta decay of 233Th into 233Pa. Unfortunately, the second beta-decay of 233Pa takes a longer time to complete, so that 233Pa is in danger of capturing another neutron (the r-proces) and becoming 234Pa, which beta-decays into 234U, which is not a fissile, and wastes a neutron in the process. To prevent this undesirable outcome, ORNL proposed to extract the protectinum 233Pa chemically from the system and taken out of the reactor so that the 233Pa could decay into 233U free of danger of capturing another neutron. You will see the immediate problem with this proposal, because if you could extract 233Pa quickly enough, it will decay into pure 233U, with which you could make atomic bombs.
Fortunately, I found a way out of this trap (the basis of my first patent), which is to design a two-fluid molten salt reactor, where the fuel 233U is carried in a different salt (the fuel salt) than the 232Th, which is carried in a blanket salt that circulates into the core from a large pool that holds the blanket salt. When the 232Th is in the core, it is irradiated by neutrons released by the fissioning 233U, so the 232Th becomes 233Th. The circulation is so fast, that within seconds the produced 233Th has flowed out of the core to enter the pool, where absorption by the copious amount of 232Th shields the 233Th from further neutron captures. With the pool sufficiently large compared to the core, almost all of the 233Th has a chance to beta decay to 233U. In the meantime, other parcels of the 232Th carrying small amounts of 233U that exists in the pool circulate into the core where there is both high-energy neutrons and low-energy neutrons. The high energy neutrons can strike an atom of 233U and knock two neutrons out by what is denoted as a (n,2n) reaction. A 233U nucleus that experiences a (n.2n) reaction becomes 232U, which is a weapons deterrent because 232U in its decay chain can emit high-energy gamma rays that will interfere with the timing mechanisms of bombs as well as sicken or kill workers trying to assemble such devices. An atom of 232Th in the blanket salt that experiences a (n.2n) reaction while passing through the core will become 231Th. 231Th is a relatively long-lived radioisotope, but there is always a small fraction that will beta-decay to 231Pa, which has a reasonable chance to neutron capture and form 232Pa that will beta decay to give more weapons-deterrent 232U.
I hold the worldwide patent on the design using sealed carbon-fiber-reinforced-carbon tubes to construct corrosion-resistant two-fluid molten-salt reactors (2F-MSRs). The motivation to get intellectual property protection was to prevent other people from trying to monopolize the technology for selfish purposes. If you want to build 2F-MSRs this way, Astron Solutions will grant you a license at an attractive fee. We want as many interested parties as possible to use this reactor to stop climate change, which is our motive and highest priority.
Frank, what are the most important technological, budgetary, and political hurdles that are preventing molten salt technology from scaling up faster than it is currently?
Well, I think things are changing. The roadblock used to be political. A battle broke out between a Fermi faction, as represented by Argonne National Lab, and a Wigner faction at Oak Ridge National Lab between going to a 238U-239Pu closed fuel cycle, using liquid sodium fast breeder reactors, and a 232Th-233U cycle using MSRs. Historically, that battle got resolved partly on technical ground because Oak Ridge hadn’t really worked out the chemical part, but also on political ground because Argonne just had more political clout than Oak Ridge. It’s a shame that this battle ever happened. During Richard Nixon’s administration, President Nixon decided that because California was involved in the sodium fast breeder concept, the R&D on breeder reactors should come to California and that the Oak Ridge project should be killed.
Now I think neither project should have been stopped. If you look at the Manhattan project for guidance, the US felt it had to develop the atomic bomb before the Germans did. Of course, it turned out the Germans weren’t close, but nevertheless, at that time you didn’t know they weren’t close to making an atomic bomb. Two different paths might succeed. One was a 239Pu bomb; the other was a 235U bomb. Faced with that choice, the Manhattan Project did the prudent thing: to try both paths and hope to succeed on at least one. Both paths bore fruit.
The 235U bomb was dropped on Hiroshima; the 239PU bomb, on Nagasaki. It’s much easier to make plutonium once you know the plutonium chemistry, which was all figured out at Berkeley. So a huge historical tradition existed in California that liked plutonium.
So, the Oak Ridge invention was killed, and nobody dared to try to revive it. In some sense, the nuclear establishment in the United States turned its back to the thorium cycle. No other country dared do what the United States was not willing to do. Only now, with the pressure to decarbonize because of climate change, are people ready to re-evaluate all of humanity’s options.
Frank, now that we’ve worked right up to the present, I’d like to ask for my last question for you to give your advice on what the future looks like. So best case scenario, if molten salt technology is ramped up on the industrial scale as you want it to be, what does that look like? What will molten salt technology contribute overall to mitigating carbon emissions?
Well, I’ll give you an answer you may not like. If you let industry take over the technology, and exploit it, nothing may change, nothing. Not making any large-scale adjustments has its attractiveness, okay? You can continue doing all the things that industry currently does that’s bad, in particular, you won’t think about waste streams, right? That’s somebody else’s problems. The whole problem with where we are today are waste streams. Whether you talk about plastics or greenhouse gases, the emphasis is always what’s on the front end, how much is possible to consume, and in what quantities. Don’t worry about the back end. That’s somebody else’s problem.
Molten salt technology done right will still have its own waste stream. You have a natural, affordable solution, and therefore you should get into a mode where you think through the whole cycle. It’s a mantra that environmentalists like: Recover, reuse, recycle. You’ve got to do that. The only things that are sustainable in the long run if we’re not talking one hundred years or even 1,000 years is that you’ve got to recycle. All the sustainable outcomes in nature run in cycles. There’s the carbon cycle. There’s the water cycle. Salt cycle. Magma cycle. They’re all cycles. We’ve got to do that if we want human civilization to last. It’s not enough just to become what many people hope we will become, space-faring. Before we leave the planet, we’d better leave it in a good condition for all it inhabitants. There is no planet B, okay? That’s the first thing.
The second change I think we will see is something that the DoEis already pushing, which is using nuclear energy in ways that are different than just generating electricity because just generating electricity is not a total solution. People think, “Oh, everything will be electrified. That’s the answer.” Is that true? Is electricity the only thing that you use in your life? Where do your clothes come from? What about your food? Shelter? Culture?
So, what’s the lesson there, Frank?
The lesson is that the emergency is here, and we’ve got to do what’s doable. What’s doable now is fission. It’s okay to use fission on a century kind of timescale. Hopefully we’ll get to fusion, but it’s not a slam dunk. If it’s not, we’re going to have to have good breeders. There’s enough uranium and thorium on Earth to already last a billion years, okay? That’s probably long enough, but we’ve got to develop a mentality that human wealth is not measured by the quantity of our material possessions.
We should be okay (laughter).
Yeah. Thorium and uranium are very common. I don’t know if you realize this. The best radioactive dating is based on these two coincidences. One is that half-life of 238U is the age of the Earth, the other is that the half-life of 232Th is the age of the universe (laughter). By that coincidence, astronomers are able to check on the theories of planetary and stellar evolution and the theories of cosmology.
Wow. Frank, that’s kind of full circle back to the beginning of your career.
Yeah! Well, as I told you, I like these stories. I’m writing a book that probably won’t be finished. The tentative title is The Story of Astronomy.
Well, on that note, Frank, I am so glad that we connected and that you were able to share all of your stories with me, so I want to thank you so much. It’s been a great privilege spending this time with you.
Well, I really appreciate your doing this.