Robert P. Kirshner

Zierler:

Okay. This is David Zierler, Oral Historian for the American Institute of Physics. It is April 5, 2021. I'm delighted to be here with Professor Robert P. Kirshner. Bob, it is great to see you. Thank you for joining me. 

Kirshner:

It's a pleasure to be here. It's a pleasure to be alive after this pandemic. 

Zierler:

You've got that right. Bob, to start, would you please tell me your titles and institutional affiliations, and you'll note, I pluralize everything. 

Kirshner:

Right. Well, sure. I am the Clowes Research Professor of Science at Harvard University. Doesn't specify which science. And I am also -- well, research professor means they don't pay you. You don't teach, but they collect overhead on your research grants. So, now that I don't need an office or parking space, I have become the perfect faculty member. And the other job, that I took up five years ago, coming up on six, is as Chief Program Officer for Science at the Gordon and Betty Moore Foundation. You know, Gordon Moore’s money doubled every eighteen months for several decades. 

Zierler:

It's the Moore's law of finance. 

Kirshner:

After a while, it was just too much. A very modest and generous person deep down, Gordon and his wife Betty set up a philanthropic foundation. About 40% of the foundation is for basic science and I'm in charge of that. So that's about $100 million a year and that's a weight of responsibility but its also it's a great opportunity to help basic science go forward.

Zierler:

Bob, let's unpack both. First, at Harvard. Who is or was Clowes? 

Kirshner:

Clowes was a medical doctor connected to the Eli Lilly pharmaceuticals who was a Harvard graduate and he and his family set up this particular endowment. Harvard has this very big red book about all of the endowed chairs. When they give you the title, they give you the book. This one is for somebody who is a scientist and who is really interested in undergraduate teaching. For many years at Harvard, I ran a big course in the core curriculum for people who weren't going to take any other science course. In the beginning, I called it Matter in the Universe. And then, as a result of our own work on cosmic acceleration, I realized that was not the right title. So I changed the course name to The Energetic Universe. Because if it turns out two thirds of the universe is not matter, but dark energy, or whatever that stuff is, that's a better name. The course is about the lives of stars, especially exploding stars, and then it's about cosmology. But it's a way to get people to start to get the astronomical picture in their heads, that your circle of friends, your country, your planet is not the whole thing-- we are part of a much bigger ensamble, which doesn't really care very much about you. Some people don't like that. They think they are the center of the universe. I told them that if the universe expansion is truly isotropic, then yes, you have as much right to think of yourself at the center of the universe as anyone else does, which is not exactly the same as saying you are the center of the universe. 

Zierler:

Bob, as you describe it, I can understand why it's in Harvard's interest to retain you as a research professor, but from your perspective, why not simply have gone emeritus when you joined the Moore Foundation?

Kirshner:

It's the same thing. It's just, you don't sound like you're a fossil. Part of my deal at the Moore Foundation is to have twenty percent of my time for research, and I've been doing that. Now, a sensible person would do that by taking the summer off, or a day a week. I do it by having twelve seconds out of every minute as my research time: I divided it up more finely. 

Zierler:

In terms of your affiliation to Harvard, on a day-to-day, or semester-to-semester, do you have graduate students? Do you sit on thesis committees? What's your interaction with the department at that level?

Kirshner:

No, I'm not doing any of those things anymore. I don't participate in job searches, or vote on stuff. I don't go to the department faculty meetings. I'm invited to the Harvard faculty meetings for the Faculty of Arts and Sciences, but they are a form of ritual theater. When you're department chair, as I was for nine years, you have to go, when you're a house master, as I was for seven years, you have to go. By the time they're done reading the memorial minutes, which are the obituaries, there's not much time left over for governing the university. One item that is quaint and interesting -- you may know about this -- is that everyone on the faculty at Harvard has a Harvard degree. Did you know that? Because if you don't have one when you come in, we give you one. We give you a master's degree. Just for showing up. So, at the beginning of the year, all the new faculty -- well, not all, but most of the new faculty are from somewhere else, and they don't yet have a Harvard degree. We make sure they have one. So, how long does that take? Quite a long time. So, by the time you're done with the obituaries and the honorary degrees, the faculty meetings are kind of a -- and then, of course, when there's a real topic, it's always the same people who have the desire to share with you their innermost thoughts. Or as we like to say, "I agree with everything you said, but I haven't said it yet."

Zierler:

Bob, given that you're able to devote twelve seconds of every minute to your own research, and given that you are ideally situated in terms of directing so much funding toward basic science, I wonder how your position at Moore might be effective for your own work. 

Kirshner:

You have to steer clear of any self-serving thing. You cannot use the foundation to support yourself! But, you can come close enough to keep your brain functioning. For example, I've made a grant to Ryan Foley, who was a post-doc at the Center for Astrophysics for many years, and with whom I've worked very closely, and now he's on the faculty at UC Santa Cruz, which is not so far away. The idea was he would use grant funds to hire a post-doc, and the post-doc could be somebody that was interesting to me. So, we've done that.

David Jones, who was Adam Riess's graduate student, is a post-doc at Santa Cruz, and supported by a grant from the Gordon and Betty Moore Foundation to Ryan Foley. I talk to him every week. I talk to my Harvard research colleagues every week. They're not at Harvard anymore. One of them is in Cambridge, but its Cambridge, England: Kaisey Mandell. Pete Challis, who's worked with me for decades, is back helping his aging parents in Ann Arbor, Michigan. David and Kaisey and Peter and I Zoom, which we were doing before the pandemic, every week. I have a big project on the Hubble Space Telescope with them that is finally coming to fruition.

So, there are a lot of things that I got started in the decades when I was at Harvard, including that big thing we call RAISINS. That’s an anagram for SN IA in the IR. This project uses infrared observations of type Ia supernovae at cosmological distances to measure the history of cosmic expansion, and place constraints on the nature of the dark energy. It's a pioneering thing, really, and it's how we're going to do things in the future with the Nancy Roman Telescope, formally known as WFIRST. We're just about wrapping up RAISINS. You know, it's hard for me to have the concentration to do the hard work. That's why it's great to have a post-doc who gets up in the morning and works on it all day, and then you check in and see how things are going. David's done a really good job on that.

So, to answer your question directly, no, I don't have any more students, but I do have this ongoing research program. And then, because I've been woven into the work on supernovae and supernova cosmology, and all that stuff, for decades, there are a lot of projects that kind of come to fruition, kind of late in the day now. I’ve been a co-author on about fifty papers since coming to the Moore Foundation. I didn’t write all of them, but I have read all of them. Depending on how busy I am, what I like to do is read the paper from beginning to end in one sitting, if I can, and if you can't, you better write to the author and say, "I understand this stuff and I still can't read it from end to end." Make sure the title is right. Make sure the abstract, which you should have written last, but they always write it first, is good enough so that when somebody's looking on the ArXiV server, they get the point from that snippet, and they can decide if they want to read that paper.

So, I work on editorial stuff a lot. I write better than most scientists, so that's helpful. Scientific papers don't have to be burnished bits of prose, but they have to be comprehensible, and they have to say exactly what you mean. What I always tell the postdocs and students is that it's not a mystery novel either. Don't hide everything until the end. It's not a newspaper article either, but the first paragraph ought to tell the reader what this is about, what you've done, and why it's important. Start there. But sometimes people have these -- I don't know what you'd call it. Sort of a ritual boiler plate, where they must refer to the classic papers. Okay, yes. Must refer to the classic papers, because otherwise, the referee will write to you and say, "I am the anonymous referee, and there are too few references to my pioneering work in this field." And then they'll write to you separately, when it comes up on the archive, and they'll say, "Hey, you didn't put in enough references to so-and-so."

Zierler:

Bob, a question we've all been dealing with. We're a year plus into the pandemic now. We can just start peering around the corner. For you, both in the world of observation, and in the world of basic science grant making, what has the past year looked like? In what ways has your own research agenda been influenced for better or worse, and how has the Moore Foundation, in general, responded to these things?

Kirshner:

My own work has, as I just described, been remote for the last five years, really, mostly Zoom sessions with my research colleagues. What I miss is going to the meetings, the American Astronomical Society meetings, National Academy meetings, or even teatime at Stanford, which is close enough to ride my bike. But basically, the mode that I'm in is the same as it has been for the past five years for my scientific research. At the Moore Foundation, the President of the Moore Foundation is Harvey Fineberg, who used to be the head of the School of Public Health at Harvard. And then he was the head of the Institute of Medicine. I mean, he is a well-known figure in public health. And he's an advisor to the national academy that gives advice to the nation on questions about the pandemic. Anyway, he's been very cautious. We're not going back until -- well, we don't want to embarrass him by getting sick. Anyway, he has a weekly briefing for us, which is great. The actual work is making the grants. We can do that pretty well, because we have a backlog of good stuff we want to do. But looking forward is not as easy, because those new ideas come from hearing a talk at a meeting, or talking to a grantee about what’s new in their field. The way we work often does not have an open call, our staff figures out what would be the most interesting thing to do in a field that is too risky or otherwise not funded very well by the Federal agencies. We figure out the outcome we are looking for and then we go find the people who can execute that work. That’s the aspect that’s damped a little bit, the prospective part.

And the other thing that I really miss, where foundation staff make a concerted effort to be helpful, is that the people who are doing the work, and that includes astronomers and their telescopes, it includes oceanographers and their ships and geologists and their field work, but also in the lab, lab work, have been under very difficult constraints. For a long time, you couldn't have people in the lab, and then you could only have one, and they have to keep the density down and all that. So, they have been delayed quite a bit. I wrote all the grantees a nice letter saying, "We understand the problem. Keep your research group together. We know it's going to take longer to do the things you’ve laid out. And we understand that time is money, so if it's going to take longer and you keep your research group together, we're going to have to give you more money." We've done that in a proactive way. We've given extensions of time, and this thing I didn't know existed -- a cost extension.

You know, I had grants from the National Science Foundation for decades. I never got more money. I'm worried about the flow of people. You know, the universities decided they had a financial problem. That was a year ago in 2020. It wasn't as bad as they thought, but they thought they had a very bad financial problem, when the markets plunged at the beginning of the pandemic. As a result, they've been very cautious about hiring for this year. So, the post-docs haven't become assistant professors, and the graduate students haven't become post-docs, and people's theses are going to be six years instead of five. So, the pipeline is clogged in this odd way. I mean, that's a way to talk about it remotely, but if you think about it, that's somebody's life. It's not going very well, and they're not doing the thing they ought to be doing. So, we know that it's going to require extra resources just to keep personal tragedies from happening. I said if you have somebody who's in this post-doc apocalypse, and they have a two year post-doc and they have nowhere to go, let's talk about it and see if there's a way to extend this and heal the problem up a little bit. Now, that is not a national solution. That's just for our grantees, and we're not big enough to do it broadly. NSF is big enough, and whether they will act swiftly enough, I don't know. 

Zierler:

Is Moore big enough for the NSF to pay attention to what you're doing?

Kirshner:

Oh, they love us so much. It's a joke. Well, let me say this more accurately. They love private-public partnerships. 

Zierler:

Well, sure. It's less out of their pocket. Why not?

Kirshner:

No, no, no. It's not just that. They get a positive pat on the head. The program officer at NSF is encouraged to bring in funds from the outside. Sloan's done a little, and Simons Foundation has done quite a lot, rather publicly. Kavli makes a career of it. We do some, but our -- it's still a family foundation. Gordon is still alive, and everybody defers to his views, which is great because his views are very good. He's a very modest person, so we don't label everything Moore Foundation this, Moore Foundation that. But we do quite a lot. For example, NSF has put a $1billion into LIGO, and LIGO is a phenomenal thing. A new window on the universe. Well, not really a window, because you're actually listening. It's like new earphones for the -- I don't know. Anyway, something. They have a very ambitious program of upgrades that's mapped out thoroughly for the next five years, maybe ten. And they're going to squeeze the light, and they're going to do all this crazy stuff to increase the sensitivity. It's great. But once they do that the biggest source of noise at low frequencies for LIGO, which is really important if you want to see the in-spiral of neutron stars, which we really do, or get a longer data string as black holes merge. The biggest source of noise will be the mirrors. It's not just the reflectivity, it's exciting the quantum states in the mirrors. Crazy. Who knew that coatings had those bad properties? The NSF program officer for LIGO said, "Jeez, just I don't have money to develop better coatings." I said, "That's a joke. How can that be? This is a $1billion thing." And he said, "No, we don't have any money, because to do all the things we said we were going to do takes all our budget." If you talk to the other side, the Caltech people about how their budget is from NSF, they say, "Oh, Jeez, it's just barely enough." Anyway, the point is that they don't have enough leeway to do something --

Zierler:

I see where this is headed. Moore can provide boutique support. 

Kirshner:

Yeah, well, we can do things faster. I don't need a committee. I can decide. Well, within limits, I can decide. 

Zierler:

So, if there's this need with LIGO, specifically, on mirrors, you're nimble enough, you can come in and say, "We can cover that." 

Kirshner:

Well, Marty Fejer came over from Stanford, explained how we just had to do this, and I thought, well, maybe we do it, maybe we don't. But in the context of private partnership, NSF loved it. In my view, the biggest leap forward for the science will be to improve the sensitivity of LIGO. If you do it by a factor of two, the volume goes up by eight, so the rate of finding neutron stars and black holes would be eight times bigger, even if you only get a factor of two in the improvement in the mirrors. Our grantees have a very good program of research that is mostly empirical, but also some theory, and they're following a couple of paths. They're going to be ready pretty soon to propose what the next coating ought to be, and it'll be better. And they're thinking downstream, you know, when you make a cryogenic LIGO, what will that be? So, that's a development project that NSF just doesn't have the resources to do, and we can step in and do that. That's not the only one, but that's a good example. 

Zierler:

Bob, before we go back and develop the personal narrative, let's get some terms straight now. LIGO is a great example. From your perspective, it's clear now where the field is, that observation is really driving cosmology. So, for you, the terms astronomy, astrophysics, cosmology, have they shifted over time relative to where you started at the beginning of your career and where we are now?

Kirshner:

Yeah, it's sort of funny, isn't it? It's really all astronomy. 

Zierler:

Says the astronomer. 

Kirshner:

But the physicists feel demeaned if you call them astronomers. 

Zierler:

They do. 

Kirshner:

They do. They're such snobs. But what has happened is that astronomy has just broadened out. So, when Hubble was looking at cosmic expansion, he did not understand general relativity. There's no question about it. And luckily, Robertson was there at Caltech, so at least somebody did. He didn't really understand that the context was a four dimensional general relativistic world the way Eddington did, or Lemaître did. So, the idea of who was an astronomer, and what they should know, broadened out, and it broadened out just at the point when I was in graduate school. Kip Thorne had just developed a course in gravitation, and Caltech graduate students all took that course. I mean, astronomy students. The change from astronomy as positions and brightnesses, to understanding the physics has been underway for a long time. From the beginning of spectroscopy, really, people have really looked into the physics and chemistry of the universe as part of astronomy. But I think the way people see themselves changed. I remember, the great Allan Sandage, said to me one time -- I think I was still a graduate student and I'd worked on a way to use observations of type II supernovae, the ones that have hydrogen, to get their distances. And he said, "Oh, this is really different. You're an astrophysicist." I thought, “eh?” So, I've never gone into that terminology game. I know there are people who call themselves cosmologists, and I know there are people who call themselves astrophysicists. It seems to me that astronomy has gotten bigger and deeper, and is more interested in the physics at the bottom of it. So, is it just semantics? I don't know.

I can tell you that the graduate students at Harvard wanted to change the name of the degree. We said, "You're getting a PhD in astronomy." They said, "No, no. We want it to be," I can't get it right. I hated it so much, "Astronomy and Astrophysics and Physics," or something like that. So, it's this big, long thing, but it's kind of like wearing a badge. The badge is, "I know general relativity and I know people who do quantum field theory." So, it is an interesting thing, and the idea of being a cosmologist, I think, is something that, as a branch of theoretical physics, mostly, and then experimental physics, too, certainly took hold there, I guess, in the eighties. It's become a kind of term of ours, yeah. 

Zierler:

To the extent that cosmology -- maybe this is heresy as well, to some degree, but to the extent that cosmology is sort of stuck right now -- I mean, where are the big advancements in inflation? How much closer are we to t=0? What is dark energy, what is dark matter? All of these things. Where are the advances in observation that are going to unstick the theoretical areas of cosmology?

Kirshner:

Well, the observational program ought to follow the observational opportunities. It's good to have a theoretical motivation, but if you want to know more about the universe between redshift 10 and redshift 1000, which is still mostly unstudied, you'll want to build JWST, an infrared telescope with great sensitivity, and you'll want to build radio telescopes that will sense the H1 emission at high redshift, and so on. You'll look at the growth of structure, and that will be a way to tell more about the nature of dark matter and its activities. So, I think the smart thing to do is to push where you have the tools to push. Twenty-five years ago, I sat on a committee in windowless rooms with NASA engineers for so long that it has been totally erased from my brain, but at the end of it, Alan Dressler, and a bunch of us, wrote a report – twenty-five years ago, now -- that said you should build a successor to the Hubble Space Telescope, and it should work in the infrared. And after a long winding path, and we're not done yet, that's the James Webb Space Telescope. So, I think that's one path.

I think the other path is, of course, the microwave background. They're not done, and as you know, the claim is that you can learn more about the nature of inflation if you can measure the B-modes, the polarization structure, in the microwave background. Okay. Now, there was an unfortunate chapter where people said, "We saw it," and it turned out maybe it had to do with dust. So, that means the next time, which is coming soon, that they discover it, or put a limit on it, they're going to be super careful. But at the Moore Foundation, we have actually been funding for many years the development of the detectors for BICEP, and for the other one, POLARBEAR. So, we have two horses in that race, which is good. We only need a place ticket.

Anyway, that'll help, I think. It's already the case that the most popular inflation models are ruled out by the present data -- you know, ten year ago models. And the quest for direct detection of the dark matter has been tough. I mean, people have done great work pushing those limits down, and spending their lives in dark places, in mines. I think in the afterword to my book, I said something about talking to the graduate students at Santa Barbara, and they were on their way to South Dakota to go down in the mine to build the apparatus. We were sitting outside watching the dolphins go by, and what does that tell you? That tells you that people take the idea seriously. So, that's coming back to your theoretical notion. They take the idea seriously. If there's WIMP-like dark matter, then you should see the recoils, and you get down there to get away from the cosmic rays, and you build a more and more sensitive thing. The last time I was on campus at Stanford, because it's bicycle distance from the office of the Moore Foundation, we went over to the lab at SLAC where they were building whatever it's called now, the big Xenon one. It was called LUX. It has some other kind of X name in it for xenon. But anyway, that's a WIMP dark matter detector, and it's an impressive piece of technology, and it's great. But you know, maybe the dark matter is not WIMPs. Maybe it's axions. Axions have a reason to be. They're the answer to a question in particle physics. And we don't know what their masses are, so even if they're light particles, creating the mind-bending name of “light dark matter” that could be sufficient for the astronomical problem. So, one thing I've done at the Moore Foundation is to fund some people who are doing axion searches. Do I think they're going to find the dark matter? What if they did? Wouldn't that be good?

Zierler:

What if Ray Weiss was onto something in 1985?

Kirshner:

Yeah, yeah. But it's a different attitude, too. To the experimental physicist, setting a better upper limit is an achievement that is widely recognized as good work. Whereas for astronomers -- now we're getting somewhere. For astronomers, actually seeing something is more rewarding. I think that's why -- well, it's a different culture a little bit. At the Moore Foundation, it wasn't my idea, but we're doing a lot of laboratory scale tests of fundamental physics, including looking for the electron dipole moment. Well, you know, electron dipole moment. Come on. You're not going to see that are you? The real prediction is about 14 orders of magnitude below the current upper limits. But if you did see something, it would be exceedingly important because it would tell you about physics at energy scales far beyond where LHC can reach. I've tried to learn enough to step back and see the big picture of how these things are related to one another. Now, your question was about theory. They're not having as much fun as they were, I would say. They were having a lot of fun when the models of inflation accounted for everything that we knew about isotropy and so on. That was good. The question is, can they predict something that we didn't already know?

Zierler:

I'll just note parenthetically here that we're at the forty year anniversary of inflation right now. 

Kirshner:

Maybe the Federal Reserve has something to do with it. And as you know, the evidence that there has been exponential expansion recently is something that I've been working on, and it shows that this approach of thinking of the properties of the vacuum has got some legs to it. The Higgs mechanism also has this quality and that is why the theoretical physicists loved dark energy so much, because it sounded something like the kind of theory they were inventing for particles. Well, I don't know. I'm trying to help pin down the inflation story. Our grantees are making better detectors for the CMB, and the Moore foundation has helped study the recent universe better for clues to the nature of the dark energy. JWST and HERA, (a radio telescope in Namibia we’ve helped to fund) are going to look at the universe in between redshift 10 and 1000, and there could be some surprises there about the way structure formed. It may turn out that's a good clue to dark matter. Was there hot dark matter at some early time? Or could there be not just one, and not just now, but some in-between stage of exponential expansion driven by dark energy? Well, it seems a little desperate, but maybe we need it to reconcile the local expansion with the CMB measurements. Anyway, I think your premise is right, that the observational work, the experimental work they like to call it, leads the way because there are so many theoretical possibilities, they need some guidance. That's observational -- LIGO, what's the O in LIGO? Observatory. They've finally earned it. 

Zierler:

Right. It's not controversial anymore to call it LIGO.

Kirshner:

No, but it was. 

Zierler:

Yes, that's right. 

Kirshner:

It was. Jerry Ostriker beat them over the head on this. Anyway, he doesn't do that anymore. The idea that you could really test these things is okay, but I think you have to be more in the exploring mode. To say to yourself, well, we've got a few ideas, and they're pretty good, and they're certainly good enough to motivate people to look for WIMP dark matter. That was a good idea. But, you know, if it's supposed to be the lightest supersymmetric particle, how's that supersymmetry doing? Not too much signature of it at LHC. So, again, I've had to -- I don't know what the right word is -- take a bigger view. Take a bigger view, because when you're trying to lead an observational program in a very competitive setting, and you're working in a big team, and so on, you don't have time for a lot of other stuff. Yes, you go to the plenary talks, and you hear the people who are trying to put all the pieces together, which is great, but there's so much that you have to do in the details of your own work. It's not all fun, and you have to do it as part of the observational work, that you don't have the luxury. Well, you do a little, but you don't have the luxury of the grand view. On the other hand, I talked to Mike Turner, I talked to Jerry Ostriker, I talked to Paul Steinhardt. I know all these people, and they do nothing but think of these things. Of course, that's been very healthy.

So, I would say, your perception is right that we've got some ideas that we keep talking about. We keep talking about the dark matter, we keep talking about inflation, and yet, where's the smoking gun? Well, my idea is, you do the things you can do? Why don't we build an infrared space telescope? And then I'm helping at the Moore Foundation to build HERA. That's one of these high redshift 21-centimeter things. They've been slowed down by COVID. Like, in Namibia, you're trying to build something. The PI can't just fly over there from MIT and see how things are going.

So, I would say, there are opportunities for a foundation to intervene -- is that the right word? -- where you can help. What you see is the nature of the funding agencies is that they're besieged. There's too much stuff being asked of them, and they don't have ample resources. They have kind of level resources. So, when they make a grant, they trim off some bit of it, and the converse is that if a foundation were to supply that, you could make the whole thing way better. Like, a $1billion thing made eight times as good at finding neutron star collisions if you develop better mirrors. That would be good. And, it's at a few thousandths of the cost. Millions of dollars, we're talking about here. So, that's a good bargain for science. But you also have to be willing to take risk. Not all these things are going to work out, and some of them will sound important now and maybe won't be. Others, maybe it's 25 years from now that we'll say this was a clue that we're glad we have. So, I think, deep down, I have the confidence that sticking to the basic research, not necessarily trying to test the models, but in the mode of discovery, is still an appropriate thing. Astronomy is still a young enough science. But for inflation, I think we're very nearly stuck, that even if you improve the measurements, and we certainly hope they will, that there's always a way out. There's always a slightly different kind of inflation that will evade the limit. With dark matter, we keep expecting it, any month now. But every time they open the box, there's nothing in there. 

Zierler:

Well, let's engage in some history now. Let's take it all the way back to the beginning. Let's start with your parents. Tell me about them. 

Kirshner:

Well, 13.7 billion years ago, the atoms that became my parents were all hydrogen and a little helium. And then there were stars, and the stars made heavier elements like carbon. Oh, that's good. And calcium. Iron in your blood. And my parents' blood, actually. So, my parents are -- trace their origin back 13.7 billion years. 

Zierler:

This sounds like a physicist's version of Genesis chapter 1. 

Kirshner:

Exactly. Well, where'd your parents come from? They came from the cosmos, so I am a child of the universe. I know that. My father grew up in New York City, and when Pearl Harbor happened, he was in ROTC; he could type forty-five words a minute; he had taken flying lessons; he was a radio amateur; and the day after Pearl Harbor, he went to sign up, and they said, "We have another organization that might be good for you." But the OSS was offering him a job sitting on an island in the Caribbean, and reporting on the ships going by, and so on. That was one possibility. And he'd done a physics degree -- oh, yeah, I forgot to say that -- at NYU. And then, there was another branch where they were worried about German spies transmitting stuff, and they needed radio direction finding to track them down. So, somehow, Dick Kirshner got steered into that, and basically, he became a civilian working for the Signal Corps. It was radio direction finding, and then it was building receivers, and then it was radar. So, my father's whole life was about defending America with electromagnetism, one way or another.

The interesting part is that my mother grew up in New Haven. Yankees and Red Sox fans. This is bad news. Cultural, big difference. My mother went to Albertus Magnus College, a Catholic college where she was class president and studied chemistry. When she graduated, she was offered a job at Yale washing test tubes in the chemistry department, or the Signal Corps. They were looking for college educated women -- because it was a manpower problem -- personpower -- they needed people to do stuff. And you could go to New Jersey and learn to be a person who built radios, and my father was the instructor. Well, you know, you could be fired from your faculty job at Harvard for this, but nevertheless, this became a romance. They got married, and I was the second kid born in 1949. They were in New Jersey, and it was Fort Monmouth, New Jersey, and I was born in Long Branch. And we moved to Rome, New York.

Zierler:

Rome, New York. Oh, I know Rome. I was born in Utica. 

Kirshner:

Oh, for heaven's sakes. Well then, I don't have to explain to you, there was the Rome Air Development Center at Griffiss Air Force Base. 

Zierler:

That's it. 

Kirshner:

So, anyway, we did that when I was one, I guess. I don't remember that very well. And then my brother and sister were twins, born in 1952 when I was three. I remember that because we were in our Studebaker outside the hospital, and my father had brought a box of chocolates and my mother waved from the window, then she brought home the twins. That meant, there was my older brother Johnny, and me, and the twins, and my mother and father in a two room apartment in Rome, New York. Somewhere in there, my mother got the idea, "Dick, why don't you get another job and get us out of here?" Anyway, they liked Rome. They were woven into that community. My father was the Cub Scout master. My mother did community theater stuff. We knew the people who ran the Kent floor cleaner company, and Gordon and Sarah Kent were mentors for my mother. Rome was the site of Fort Stanwix during the American Revolution. This was a big deal, with the American flag first flying in the face of the enemy. Whether it's true or not, I don't know. Anyway, they made a big deal about Fort Stanwix. They were community boosters for the Kents, and they wrote a pageant, and my father was the narrator. He was a very good speaker, my father. My mother's the theater person.

Anyway, that was Rome, New York. And then we left when I was in second grade and my father worked briefly for Raytheon, as almost every electrical engineer of the era did. And then they fired everybody because they lost the contract on some missile or something, he landed on his feet at -- I guess he was at Lincoln Labs. And then, when MIT was a little embarrassed to have these big contracts from the Air Force doing classified research and development they set up MITRE. MIT Research and Engineering. My father was a systems engineer, whatever that is, at MITRE. He opened their New York office, which was kind of funny because he never moved. So, in his desk, in Bedford, Massachusetts, the phone would ring. It was a New York number. You know, "MITRE Corporation, New York office." That work was classified, and he never told us anything. I really didn't know what he did. You know, in school, sometimes they ask you fill out a form, what does your father do? I said, maybe he's a detective. I really did not know. So, it was kind of a weird little business, but at the end of World War II, there were a lot of surplus radio parts and some of them ended up in coffee cans in our basement, in Sudbury, Massachusetts. I mean, we had not a warehouse, but we had a lot of radio stuff. Tubes, capacitors, resistors, chassis. We had stuff.

Zierler:

You could tinker. 

Kirshner:

Yeah. And my father was also kind of a cheapskate. He never bought a real TV, so we always had six half-broken TVs that he was planning to fix. Should have been Frank Wilczek's dad. He never fixed them so they worked for any length of time. We had radio receivers. I mean, a multi band radio receiver of the type you might have in an airplane. My father was a radio amateur. He taught us morse code, and my brother and I became radio amateurs. I remember, October '57, I remember Sputnik. Not only could you get up at six in the morning and see it, but if you tuned in on our receiver, you could hear it. "Beep, beep, beep, beep." Until the battery died. So, it's not wrong to think of me as somebody who benefited from Sputnik -- the fear of Russia, and the Cold War, and the emphasis on science for defense. All of those things helped me a lot. Like, the physics book we used in high school, the PSSC Physics book, that was a novel thing where they got MIT professors to do a high school physics book. You know, it's really good.

Anyway, my older brother and I did a lot of stuff. Honestly, that we did not injure ourselves is kind of surprising, because we built rockets with powdered aluminum. We'd ignite them and we didn't lose any eyes or fingers. I built a 45,000 volt Tesla coil, and that was okay, but the DC part was kind of hazardous. So, I built stuff for science fairs using my riches in the basement. But what was interesting about it to me was although my father would pay attention, he did not hover. The fact that we didn't poison ourselves with the chemistry sets, or break our fingers with the model airplane engines, or -- I don't know. We had a lot of freedom as kids. I know this because for my own kids, when I was encouraging them to do stuff, I did not let them just go wild out into the woods and catch frogs to dissect them. Jeez. But it was interesting.

My mother, of course, had had a science background, but she wasn't doing that. She was doing community stuff. Theater stuff, and then she got -- she was always interested in education. She ran for the school committee. And she won. And Sudbury is a regional district with Lincoln. Lincoln is very clean finger nailed. Lots of professors from Harvard and MIT commute from Lincoln, including Icko Iben the astronomer. I knew who he was after a while. Those town aspired to build a regional high school that was good enough so that the parents, who could probably afford it, did not choose to send their kids to Exeter, or Andover, or something. Well, that's my theory anyway. Some of them did anyway, because their grandfathers had gone there.

But the level of the high school, the aspiration for the high school was very high. The school committee had on it Howard Emmons, a professor at Harvard whose son was in my class, so I knew him. And I had teachers, math teachers, who had been mathematicians, sort of. I had a physics teacher who had been a physics major. And, you know, when you wring your hands in despair at the level of American science education, that wasn't the case at our place. Now, I don't want to give you the wrong impression—not everything was excellent. But, a lot of it was very good. Even before that, in junior high school, we had a guy, Frank Henry, who had been a geology student at Tufts. He had energy, and he was fun and we just loved science class. It was the best class, and we liked it the most. Sue Jewett, whose grandparents had been sea captains, or something, had a giant brass telescope that she brought to school. I remember this. It was probably October, or something, and we set it up, and we saw Jupiter. Jupiter with little orbiting things. What are those? And Saturn’s rings seemed like they must be fake. Anyway, the thrill of using a telescope was good for me. We alos had a next-door neighbor who had a telescope, and the sky was pretty dark in Sudbury. But he didn't really know how to set it up. You know, you've got to point the axle at the North Star. So, that was my puzzle. It wasn't that hard. Anyway, I figured out how to set up an equatorial telescope. You know, I didn't really do all that much amateur observing, but despite these good experiences, I didn't get the idea that you could do anything except gawk. You know, that you could be an astronomer. That never occurred to me. 

Zierler:

Bob, was the Space Race a big deal for you as a kid?

Kirshner:

You know, in school, they would get us all in the auditorium, and the Vanguard Missile would be on the TV, the black and white TV in the front of the room, and we'd watch it go up, [explosion]. Yes. We paid a lot of attention to it. It wasn't just Sputnik, but it was the race. The Space Race was a big deal. Yes. You know, for Massachusetts, Kennedy was a big thing, when he was elected. I remember I was in high school, and it was the Cuban Missile Crisis. There was some meeting at the school that evening. We didn't have the meeting. We had the president telling us nuclear war could be just around the corner. So, that's not exactly the same thing as the space race, but it was all about rockets. Like a lot of kids of my age, I definitely had nightmares about nuclear weapons. You know, you saw those images of weapons tests.

So, all of that was definitely part of what was going on, and the consequence was, of course, that there was a lot of encouragement of science, and physical science in particular, for kids of that era. In Boston, the Museum of Science, of course, is a big institution for learning. I remember going -- maybe they picked me. I think they picked me. I got to go to a lecture by Isaac Asimov. Well, I had read some of Isaac Asimov's books. Of course, he only wrote about 200. Looking back, you can see why he was able to write 200, because they're pretty thin. But it was a talk about telescopes, and it was about Herschel and his sister, and making the telescopes, Herschel polishing mirrors while his sister fed him with a spoon. Thinking back, I'm sure he was writing a book, and this was the next chapter in it. But that was a real moment where I thought, wow, this is pretty good. Then, I went to the high school library, I'd been reading books, but I took out all the books in astronomy. There were only six or eight. You know, it was James Jeans, and it was George Gamow, and it was Isaac Asimov. Anyway, I read all those books, and looking back on it, the ones with the best ideas -- Gamow was the one that had the wackiest ideas, and most daring way of saying things. I didn't realize just how good that was. But I used it again when I was teaching my class. I took his picture of the world turned inside out. It's really funny. I didn't remember it, but when I went back and saw it, I thought, oh yeah.

Anyway, I read all the books, and I thought, well, I should probably learn the constellations. So, I went out in the back yard, and this was in the winter, with one of those planispheres. You know, you roll it to the right time and figure out which way is East. I could handle that, and I learned all the constellations. I do also have a memory of my mother yelling at me out the back, "Bobby, dinner time. Come in." I was lying in the snow, you know, looking at the sky. So, I had an interest in that, I guess it would be fair to say. I got a lot of encouragement. In elementary school, I was bored silly, and they kept kicking me into the next grade. Junior high school worked better; high school very good. And then when it was college admissions time, we were in New Haven for something. I went to interview at Yale, about which I remember nothing except the Gutenberg Bible in the Beinecke Library. I couldn't believe it. Everybody had heard of the Gutenberg Bible, but you know, it's big, and the illumination is fantastic. Well, I only saw two pages, but the illumination of the text. I thought, oh, this is the genuine thing. So, I don't know. Somehow that was very impressive to me. I don't know if I was impressive to them or not, but I got early admission to Harvard, and advanced placement. So, I went. 

Zierler:

Was it astronomy from the beginning for you?

Kirshner:

Well, that's an interesting point. I was also interested in the history of science, and I don't know exactly. Well, because I was a sophomore the first day I got there, I could take freshman seminars and sophomore tutorials, and I think -- I don't want to look at my transcript, but I think I took a freshman seminar in astronomy and the sophomore tutorial in history and science at the same time, because they seemed like easy things to do. And they were, compared to the physics courses. Ed Purcell had just written the Berkeley physics text on electromagnetism, and he was my instructor. That was pretty good. When he went to Purdue, he was going to study electrical engineering, and was a really, really good blackboard artist. He could draw the field lines, and the potentials, and the dipole, and the conductors. Oh, it was just great. So, that was good. And I learned from watching how to draw a very good circle on a blackboard. Keep your arm straight and rotate at the shoulder!

Zierler:

Bob, what was your sense of the divide between astronomy and physics, for better or worse, as an undergraduate?

Kirshner:

Oh, well, at Harvard, they're physically separated by a mile. So, the observatory, which used to be really an observatory, was out of town, up on Garden Street, where the botanical gardens used to be. Well, that's where the faculty housing grows now, but anyway -- and the physics department was on Oxford Street, a mile away. Well, Purcell got interested in the 21-centimeter wavelength hyper-fine transition in hydrogen. Ewen and Purcell, Doc Ewen did his thesis measuring the 21-centimeter emission from the Milky Way and he did it out the window of -- I guess it's Lyman Lab there, on campus. I had a summer job through a Sudbury connection -- I think it the dad of one of my Little League teammates-- working at his company. Ewen Knight, it was called, and they made radiometers, radio receivers, for mostly the military. So, there was a lot of stuff there I couldn't do because I didn't have a security clearance. So, I was kind of sitting around. I'd do the solar observation, radio observations of the sun. That's pretty boring. And I said, "Isn't there something I could do?" And they said, "Well, you could mow the grass." I said, "Okay." So, you know, I wouldn't say I was at the stratospheric level. But your question was about the relation between physics and astronomy. I would say it was pretty bad.

Zierler:

Did you flirt with theory at all? Did you ever consider going down that path?

Kirshner:

No, I don't think so. The observatory was very -- the astronomy department was very good to undergraduates. I took a freshman seminar. The leader of it was Alan Maxwell, the radio observatory head, and the graduate students who helped with this were Dennis Downes, who became the head of a big observatory in Europe, and Joe Taylor, who's had some success in the world. There was a good relation between the advanced undergraduates and the graduate students. So, I knew Joe Silk -- well a bunch of them of that era, who were the next level up.

So, you could see, there was a path, but as for theory, I remember it was the junior tutorial, where they have a special thing, and in those days, it was legal to serve the children -- I mean, students -- sherry, because Massachusetts had not changed its law to twenty-one. It was eighteen. So, there was sherry, which was a big draw. And talks. Giovanni Fazio, I remember him giving a talk. I remember Bob Noyes giving a talk. And David Layzer, who was a cosmologist, gave a talk. It made me realize I didn't want to do that. It was so -- well, maybe it's just him, but it was so philosophical. And it was so little action. What are you going to do? But I remember, during the time I was an undergraduate, the pulsars were discovered, and I knew Joe Taylor. His thesis had been about using lunar occultations to measure the structure of radio sources. Well, he didn't care about that anymore. He wanted to do the pulsar stuff, so I learned something about neutron stars. But my undergraduate research work was with Bob Noyes. Leo Goldberg, who was the Harvard observatory director, was a real entrepreneur of science. And Fred Whipple was there as the head of the Smithsonian Astrophysical Observatory. They were, of course, at loggerheads.

Anyway, Leo had pioneered ultraviolet satellites that were observing the sun. That seemed like a new thing. And the data came down, and it was on the line printers. We'd make contour maps. We'd circle the contours, drawing on the printout – it seems pretty funny now -- integrating the numbers up with a calculator. But I did my senior thesis on that, and it was pretty good. We wrote a couple of papers. George Withbroe, and Bob Noyes and I wrote a couple of papers that got published, that were really my work. 

Zierler:

You're doing real science as an undergraduate. 

Kirshner:

Yes. So, they welcomed you in, and I think the frontier is closer for astronomy than for physics. It certainly was then. So, you could act -- you're not just putting the connectors on the cables, which is a fine thing to do. But a lot of undergraduate work in physics labs is building stuff. That's fine, but this was really doing the research, which was great. So, I did that, and I suspect -- well, I know, because I checked it out later -- when it was time to apply to graduate school, that the reason I got into Caltech was not that I had been the most outstanding student. In my classes, the year ahead and my class, there was Bill Press, Richard Gott, Ned Wright. It was not a crime to be in the bottom half of the class. It was okay. They were very good. You know, it's a little like, you just don't know how high the standard is because you're just swimming in that water. That's it. Catherine Cesarsky, who later became the head of ESO, and all those other things --

Zierler:

And the head of everything else. 

Kirshner:

Head of everything. She was the teaching assistant for a course that Dick McCray taught that I took on plasma physics. Plasma astrophysics. So, I worked on the sun, and I think that's why I got into Caltech. Hal Zirin, who was the solar guy at Caltech, hadn't had a graduate student in a long time. Bob Noyes had worked for Bob Leighton at Caltech and I guess he said some good things about me. 

Zierler:

Bob, before we leave Cambridge, on the social side of things, late sixties, early seventies, this is a pretty interesting time to be an undergraduate. Were you political at all? Were you involved in anything that as going on?

Kirshner:

Well, it was sort of funny. In '68, I guess, that was the most acute year. Let's see. I'm trying to get the dates right. I'm trying to remember this correctly. I guess it was my sophomore year, a friend of my roommate wrote the Hasty Pudding show. You know, it's this drag theater thing. But he said, "Oh, Bobby, you gotta be in this." I said, "Well, okay." So, I did that, and that reaches its performances in February and March, and that was just when the bust was in Harvard Yard. So, it was weird. I was doing this other thing, which was very demanding and took an awful lot of time, and I was taking math and physics courses, and they're demanding and take a lot of time. I just did not enter into it directly, the political stuff. And that summer, '68 it must have been, I went to Iowa. I went to the Ames Laboratory, which was formerly of the Atomic Energy Commission. Now, of course, the Department of Energy. Because you could get paid $100 a week. $100 a week. And you could take a quantum mechanics course, and learn to do plumbing in a solid-state lab. That's the equivalent of putting the connectors on the cables. But I did that. I learned plumbing. And if you were an undergraduate, you could plumb Helium-4, but only the post-docs could plumb Helium-3, because it cost $1000 a liter, and they didn't want any leaks.

So, I worked in that lab. I had a lot of good experiences where people were deliberately trying to encourage students to go into science, obviously. I had that, and I had previously gone to Ohio University, in Athens, Ohio, and had a summer research experience as an undergraduate. I met Bill Herbst, who later became a real astronomer at Wesleyan. So, I got a lot of encouragement. I guess what I'm trying to say is I got a lot of encouragement through these programs that were aimed at encouraging kids to go into science. It was kind of fun, I have to admit, a few years ago, to go back to Athens, Ohio, and receive an honorary degree. Honorary degree, if you ever have the opportunity, I definitely recommend it. There are no courses, there's no tuition, there are no exams. All you have to do is stand there and smile while people say nice things about you. I definitely recommend this.

Anyway, that was a really good experience for me. The Ames, Iowa thing was in '68, and I also went to the Iowa Democratic Convention. I forget why, exactly. I wanted to be working for McCarthy, which I did. Then, on the way home -- I'm trying to get the chronology right -- on the way home, my high school friend had gone to the University of Chicago, and we went to the National Democratic convention in 1968, in Chicago. He had credentials for the campus radio station. So, we went there, and it was awful. It was just an awful scene. So, that was a political thing, sort of. I mean, I got educated. And I left before I got tear gassed.

And then the next year, there was an opportunity to go -- yeah, the March on the Pentagon. I went to that. There's a picture in the Boston Globe of me reading the newspaper to the other people while we're waiting for something to happen. I don't know what. Nothing happened. But anyway, I did participate in some of those anti-war things. And then, I got a low lottery number, and I got called to the West Concord, Massachusetts, Selective Service Office. It was cold -- maybe it was March 1970 -- anyway, cold. We all showed up, and there were kids I hadn't seen since high school. We all got called to go for our draft physical. And it was national draft resistance day -- oh, great -- which meant some people had painted their bodies so that when you had to walk around in your underwear, it said political statements. Someone stole the keys to the school bus that was going to take us. I was in Cambridge, but I had to go out to Concord, and then come back in on the bus. You could not show up yourself. And someone stole the keys to the bus. When we got to the Boston Army Base, a Marine wear his dress uniform got on and yelled at us. That was kind of interesting. Long story short, I did not pass the physical. I didn't do anything wrong; I didn't cheat, but I didn't pass the physical,Ididn’t ask for a second opinion and I went to Caltech. 

Zierler:

Bob, what advice did you get one way or the other about staying at Harvard, or specifically not staying at Harvard for graduate school?

Kirshner:

Well, they gave me the most direct kind of advice: they didn't admit me.

Zierler:

Doesn't get any clearer than that. 

Kirshner:

No.

Zierler:

Did you want to stay? Was that the trajectory you thought you were on?

Kirshner:

Not really. Caltech was so clearly the best place.

Zierler:

Yeah. Why? What was going on there? Who was there?

Kirshner:

Well, we lived in Sudbury, and my mother's sister, my aunt, lived across the street, which was great. And my cousins, it was a lot of fun growing up with cousins. My cousin Shawn is a professor at University of Oregon in neurophysiology. We had a lot of fun doing stuff as kids. But I remember very clearly, we subscribed to Newsweek, but Aunt Pat and Uncle Harry subscribed to Time. I remember Aunt Pat bringing over the issue with Maarten Schmidt on the cover, discoverer of the quasars. I thought that was pretty good. So, Maarten Schmidt was there; Jesse Greenstein was the king of astronomy in a lot of ways. Those were things I knew. I knew that Bob Leighton was on the faculty. And, of course, Feynman was on the faculty. 

Zierler:

And that was interesting to you, even though that's sort of a different world. 

Kirshner:

Oh, yeah. Remember Frank Henry, the guy who was the inspiring junior high school science teacher?

Zierler:

Yeah, yeah. 

Kirshner:

Well, he quit after a while and went to work for Addison-Wesley, which was the publisher for the red Feynman books. I stayed in touch with Frank, and every year, he'd send me whatever books I wanted from their list. So, I got a bunch of them, but I had those Feynman books, when I was in high school which I liked a lot. You know, it's that illusion of understanding that you get from him. You read the chapter and you think, I understand this. But somebody gives you a test, you might think, oh, maybe I don't understand this very well. Still, that was very inspiring. Anyway, Caltech. And you know, George Ellery Hale, and Mount Wilson, and Carnegie Observatories. I didn't know all the details, but you know, Hubble. All of the observation -- and then, the 48-inch. Everybody'd seen the 48-inch and the 200-inch. Wow, greatest telescope in the world. So, those were things, but you're asking exactly the right question, because I remember that while I was a graduate student, Chandrasekhar came to visit. Austere theoretical man. And he asked that question. We were at lunch at the Athenaeum, and he said, "Why did you choose to come to Caltech?" So, I gave some version of the answer I just gave you. "Oh, it's always been the greatest place, and they have the best telescopes and..." And he said, "I would have thought it would have something to do with the intellectual quality of the faculty." 

Zierler:

Well, of course. 

Kirshner:

Which, of course, was his thing. So, that was pretty funny, and that stuck with me. And it's the answer to your question. But one thing that was good was that just a year before, maybe it's two years before, the graduate students had started to barge in on the faculty lunch. Once a week, the physics and astronomy faculty would get a big, long table in the Athenaeum, and they would sit there and discuss things. Greg Shields, I think it was, said, "Come on, let's go." And we went, and we sat down. They didn't throw us out, so that was good. There you get to know people, world famous scientists, not just as lecturers at the front of the room. Of course, for me, it was Willy Fowler, and nuclear astrophysics, that was connected to the supernova business. But I do remember -- and Christy, who had done some calculations for imploding things at Los Alamos, so that there would be enough energy to create fusion, and so on. One day, it was Murray Gell-Mann. He sat down kind of near me, and he was expostulating about neutral currents. And then, suddenly, people realized that there would be scattering, and this would affect -- Christy knew that would affect the dynamics of explosions in stars. And Willy Fowler started to think about whether there was some way that you would know that was happening from supernova observations. The way I remember this is that then, Murray Gell-Mann said, "Well, I feel like I've just given a speech to the Hungarian Academy of Sciences. Now, the Hungarians are speaking in their native tongue." He was something else.

So, I saw him again later, twenty years later. Of course, this was seared into my brain. And I said, "Oh, yes. We have met before. You had talked about weak neutral currents, and we talked about how it would affect the explosions of stars, and you said, 'Well, it's like I've given a speech to the Hungarian Academy of Sciences, and now they're speaking incomprehensible Hungarian.'." And he said, "No. That story cannot be correct. I speak fluent Hungarian." Well, you can't top that.

Anyway, some good things happened to me as a graduate student, that were not my doing, really. First thing was I didn't work for Hal Zirin. That was my senior thesis, but my junior year I worked with Giovanni Fazio, and he said, "We're working on gamma ray observations of the Crab Nebula, and we need to know the spectra. I said, "Well, that's easy enough. I'll go look up all the papers, and I'll plot up all the overall electromagnetic spectrum of the Crab Nebula, supernova remnant of 1054. So, I did that, and then he said, "Great. Now compute the Compton scattering, so that we see how the infrared photons get kicked up to gamma ray energy by the relativistic particles that are making the radio emission." "Oh," I said, "very clever." So, I did this calculation. I was a junior. So, I turned in the paper. Giovanni, of course, much too busy to read it, handed it to Josh Grindlay, who was the graduate student doing the observations of the gamma rays from Crab Nebula, and other stuff. And, well, you know, Josh gently pointed out that I hadn't quite done the calculation right. Nevertheless, I developed a great liking for the Crab Nebula, and when I showed up at Caltech, I had an NSF fellowship. That was good. $200 a month, woohoo! It was almost enough to live on. But because of my excellence, I had another job which paid, I don't know, a couple hundred dollars more for the year: I was showing the slides at the colloquium. Slides, do you remember those?

Zierler:

Sure, I'm old enough.

Kirshner:

5 cm squares. Where you put your thumb, upside down, and reading forward. It didn't take too long to get that. So, I went to every colloquium, and at every one of them, Fritz Zwicky would stand up, and tell the speaker that they were totally wrong, and that he, Zwicky, had discovered all of this in 1934 and never gets credit for it. He had this set-piece tirade. That was good. And then, there was -- I think that was the first semester. The second semester, I went to see Bev Oke, who was, I don't know, the undergraduate administrator, or whatever he was. And he said, "Well, what do you want to do?" He's Canadian, taciturn. I said, "Well, I worked on the Crab Nebula, and I really enjoyed that." He said, "Oh, supernovae." This is classic Caltech. He had a big desk, and he pulled out the drawer. He had in there a bunch of those yellow Kodak envelopes that had glass plates, which were spectrograms. These were spectra of supernovae that Schmidt had taken, Wal Sargent had taken, and Bev Oke said, "Oh, yeah, supernovae. We do it here," because they had the observing facilities all the time. He handed me this stuff, and I had no clue, I mean, no clue, what you do with these plates. But, you know, "Thank you very much." And I went back down to the second sub-basement, where the beginning graduate students had their offices, down there in the engine room. The only funny thing was that's where Zwicky had his office, too. That stuff's in my book. Anyway, I said, "What do I do with these?" And other graduate students knew how to measure the plates, and do all that stuff. So, I learned how to do all that, and that was super.

Charlie Kowal, who did the Palomar supernova search with Wal Sargent, always took a vacation in July. The galactic plane is overhead in July. You want to observe out of the plane, so that was a good time to take a vacation. And a graduate student, in this case, me, would take Charlie's turn at the 48-inch. The 48-inch telescope which I had seen in books. So, I did that, and I discovered a couple of supernovae. I wasn't going to quit until I had found them. They were awfully faint, and nobody studied them, but that's all right. Also, Oke took an interest and said, "Well, why don't you come to Palomar?" He had just built his new instrument, which was the 32 photomultiplier, multi-channel spectrograph. It was not photographic; it was electronic sensing. Kind of coarse spectral resolution, but nevertheless, it was a quantitative astronomy of a totally new kind. It was really good. And it had a lot of photomultipliers that needed dry ice.

So, the big thing for you to do, if you were the graduate student, is like watering the elephant. You grind up the dry ice, put it into the container so that the photomultipliers would stay cold. This was in heroic age, so we were out in the dome, riding below the mirror of the 200-inch, in the Cassegrain cage, and Bev said, "Well, sit down there." So, I sat down there, and he'd do stuff, finding the object, using blind offsets. And then, soon after an hour or two, he said, "Want to take a look?" I said, "Yeah." This was the era of looking in the eyepiece to guide the telescope while the photomultipliers were doing their work. And it was very disappointing. The images were kind of soft. I said, "Well, where's the galaxy we’re measuring." "Oh, well, you can't see it. Light's going down the hole." Light was going into the aperture for the instrument, and he was using a guide star and offset from it with a micrometer. Anyway, I thought, oh, this is hard work. But I did it. I liked it. This was the era of transition from being out there to having TV cameras doing that while you sat in a warm room, and going from photographic plates through this crazy halfway technology of photomultipliers, to image tubes, and other electronic gadgets for readouts. Steve Shectman built one of those for his thesis work, maybe just after. Jim Gunn -- oh, I forgot Jim Gunn. Jim Gunn was our absolute hero of --

Zierler:

What was Jim working on at that point?

Kirshner:

He was working on cosmology trying to do the Sandage program. Ho, ho, ho, that led to good feelings. So, you know, the question was whether the brightest cluster galaxies were standard candles, and if they were, could you use them to measure cosmic expansion, and possibly deceleration? So, he and Bev did that, and I was not part of the scientific work, but I knew what they were doing. Sandage and Tammann had been working on this since Hubble handed them his mantle. And I don't think Sandage liked it, that Oke and Gunn were working on it. There was friction between the two institutions, Carnegie -- Mount Wilson Observatory, I guess it was then, and Caltech. Anyway, that's another story. But Jim was working on that. And he helped me. Charlie Kowal’s summer vacation gave me the chance to find some supernovae and then in '72, Charlie discovered Supernova 1972E, which was the brightest supernova in 35 years. They were building the 60-inch telescope at Palomar, and it was almost finished but not scheduled. And Oke was in charge, so he said, "Well, why don't you go up there?" So, I went to Palomar, and I observed every night for the month of May in 1972, except for the nights when they did it on the 200-inch, because that was 64 times faster. It was like a joke. I'd work for an hour; they'd work for minute. So, if they did ten minutes -- anyway, so that became my thesis work. I had the best data in the world, because I had Bev Oke's data and my data, and the brightest supernova since 1937. The International Astronomical Union meeting was in '73, in Australia, and I got to go because Bev was invited to give the big talk on supernovae, and he didn't want to go. So, I gave the big talk on supernovae. So, through no real brilliance of my own, I got launched really well by that explosion, and I did pretty good work about it, but still. 

Zierler:

Bob, as you say, the brightest supernova in such a long time, how much of that is about the supernova itself, and how much of it is about advances in the ability to observe it?

Kirshner:

The supernovae are bright when they're nearby. So, the volume in which you're looking is small. You just have to be lucky. It's nothing you did. It's like being witness to a traffic accident. You just have to be there at the moment when the supernova goes off.

Zierler:

Are there any intellectual seeds that are planted at this time that will ultimately connect supernovae to the discovery of the accelerating universe?

Kirshner:

Yes. I had multi-channel spectra, which were quantitative energy distributions. If you're observing a black body, the temperature sets the energy distribution, and you even know, if it's a black body, how much energy is coming out of each square centimeter of the surface. An exploding star is not exactly a black body, but it's not that far different. So, if you could measure the temperature and the flux, you could get the angular size for the type II supernova, the ones that have a more or less continuous spectrum. The other thing you can measure is the velocity. From the spectrum lines, they're blue shifted coming toward you in an exploding star, so you know the velocity at which the atmosphere is expanding. Okay. Now, you've got two things: angular size, which is radius over distance, and the velocity. If you measure it many times, the thing gets bigger. And you know, in meters, how much bigger it got, because you know the velocity and how much time has elapsed. You can solve for the distance. You can solve for an extragalactic distance without knowing anything about parallax; anything Cepheid variable stars; none of that stuff where Sandage was the world expert. You leap all the way out to megaparsec distances, tens of megaparsecs, without any of that stuff.

Leonard Searle said to me, "Bob, this is like the way we do it for Cepheids: there's pulsation and there's temperature. Wesselink method, that's what it's called." I said, "Well, okay, I'll work this out." So, I worked it out and got distances to the supernovae that were some of the ones that Oke had handed me the spectra for, and had the multi-channel data for. So, I measured distances, and these were big enough distances that you could measure the redshift of the galaxy, and divide by the distance to get the Hubble constant, which looked like it might be sixty or seventy. The errors were kind of big, and we knew there was a systematic problem because they're not black bodies. But I followed that thread. I worked with my graduate student Ron Eastman on Supernova 1987A, also the brightest since forever, on doing that physics. I couldn't do it. He could do it -- the radiative transfer problem. What is the difference between a black body and this relativistically expanding scattering atmosphere? Well, you've got to work it out. Anyway, he did that as my student. I still haven't given up -- Brian Schmidt. When Brian Schmidt was a graduate student at Harvard, what did he do? He did distances to supernovae using the expanding photosphere method that I had worked on some time ago.

So, the answer is yes. I was really interested in that, and I even got notes from Sandage, who was, to the graduate students, a cryptic and ferocious figure; not as cooky as Zwicky, but terrifying, nevertheless. Sandage would write me little notes. If I got a number like sixty, he'd say, "That's not too bad. The real number's fifty-two." When I said, "Well, for this we get seventy-four." He said, "I don't know what to think about you." It's not my fault. I'm just telling you what the data said. He didn't go for that. "You're an astrophysicist," he said. He didn’t mean it as a compliment. 

Zierler:

Bob, who was on your thesis committee?

Kirshner:

Well, of course, Oke; Jesse Greenstein. Yes, Jesse was there, and he said, "Ah, chapter three, I don't think he got the physics right." And I think Guido Münch. I may be mixing this up with my qualifying exam, but Guido Münch, at one of these events, appeared, but he had hurt his back, so he was reclining and taking painkillers. 

Zierler:

Did that yield in any interesting questions?

Kirshner:

No. No, nothing. It was at that point when I realized I know more about this than these guys. That was good. And, you know, some of them had read it more carefully than others. Some were mostly errors in punctuation. Oh, this is kind of funny. I only remember the punchline. I took my thesis in, and those days you had to have your thesis typed. I guess I did it myself. I can't remember. Anyway, there was a ferocious person in the dean's office, and she would look at your manuscript and decide whether it was okay for binding. Margins had to be the right size right. She read this over and said, "If you paid to have this manuscript typed, you should get your money back." It's a good line. So, anyway, I had a thesis. I guess, we could look to see who signed off. That wasn't a big deal, because it's a foregone conclusion, as I learned later, as a thesis advisor. You don't schedule a thesis exam unless the conclusion is foregone. It's not an exam; it is a ritual. You just don't let the student show up with something that is not good enough. I had to say that a few times to some of my students. I've had about twenty students. Well, anyway, sometimes you have to say things to them. Most of them do pretty well.

Zierler:

Did you consider anywhere besides Kitt Peak for your post-doc?

Kirshner:

Oh, yeah. I got all the jobs. I got all the jobs I applied for. Maybe eight. They must have written really good letters. I could have been the Leverhulme Fellow in Cambridge. That would have been a catastrophe. What observational work would I have done there? I could have been this; I could have been that. Anyway, Kitt Peak seemed like the natural place to go. Now, Leo Goldberg, who had been the director of the Harvard College Observatory, had gone to Tucson, and he was now the director of the Kitt Peak National Observatory. So, that was kind of fun. I knew him. I had worked on his satellite. And the best part of it was the cohort of people who were there at the same time. Kitt Peak has been in an uncertain state for recent decades, but then, it was really excellent -- they were just finishing the Kitt peak 4-meter telescope, and the one in Chile came very soon after. So, it was great. You're a post-doc, wow. You could get to use those telescopes. I got a little of my own time on the 200-inch, too. That’s a coming-of-age experience. They were so nice to me. But anyway, you got to use those Kitt Peak telescopes, which were state of the art. The spectrographs were better than the spectrographs at Palomar. Roger Lynds, who was the technical genius at Kitt Peak, had done better work on quasar spectra -- even though the telescopes were smaller, some of the things you could do, you couldn't do at Palomar. I had Roger Chevalier to work with, and Garth Illingworth was there, and Harvey Butcher, who went back to Australia, but was very fine. Paul Schechter was there. So, I mean, it was a very good cohort of post-docs. 

Zierler:

There was a lot going on when you arrived. 

Kirshner:

Yes there was always this competition with Palomar, and the haves and have nots. The haves didn't want the have nots to get better. That's why it's a 4-meter not a 5 meter. Anyway, the astro-politics was a little fraught -- but I was not on that level. Below the waves, the science was great. 

Zierler:

Who was the administering agency when you arrived?

Kirshner:

It was AURA. Laundering NSF money.

Zierler:

Oh, it was AURA. 

Kirshner:

Yeah. My TIAA-CREF is from AURA. They paid into your retirement account. I said, "Retirement? Who cares.”? Now, look at that. Ten times more than it was. Not very much. I went to Cerro Tololo in Chile. And this was in the Pinochet years. It was scary. You would fly to Santiago, and then stay overnight in the hotel downtown near the Moneda, the palace that had the bullet marks on it, that had been bombed. You would walk over to the bus station -- walk? I don't know. Anyway, go to the bus station, and there'd be an envelope for you with your ticket, and you'd get on the bus, and eight hours later, you would arrive in La Serena, jet lagged, and dehydrated. But it was a whole community there. There was a whole world there, and they were so nice to you. So, that was really good, too. I deliberately thought of things I could do to go to Chile. I did that a couple times. But the fog, the pall of the military government was kind of scary. Even though relationships with the observatory were pretty good. There was nothing secret. Victor Blanco, who was the observatory director was a fluent Spanish speaker, a native Puerto Rican. So, that helped. But still, it was a little creepy. 

Zierler:

How long did you stay at Kitt's Peak?

Kirshner:

Two years. And I got a job at the University of Michigan, what we call a real job. 

Zierler:

Tenure track. 

Kirshner:

Yes. Al Hiltner, who was the director at Michigan had done a lot to help build Cerro Tololo. And I suspect he talked to Victor Blanco, or whoever he talked to, and thought I was a good guy to get at Michigan. So, I went there, and, you know, Ann Arbor is a really nice place to live, and the department was okay. But it wasn't like Caltech and it wasn't like Harvard.

Zierler:

It was an opportunity for you to build.

Kirshner:

Yeah, and there were students who were eager to do stuff. They probably hadn't applied to other places, because a lot of them were from Michigan. The undergraduates, I really liked the undergraduates, because for a lot of them, their parents hadn't gone to college. They'd worked in the transmission plant in Flint, or something. The kids were -- it's just their horizons were not all that big, and University of Michigan seemed like the best place to go, which it was in some ways. 

Zierler:

When did you get involved with what would become the Hiltner Telescope?

Kirshner:

Well, Al had moved the 1.3 m telescope from Portage Lake in Michigan, down to Kitt Peak. The people who were in that consortium, so that was MIT and Dartmouth -- wrote a proposal to NSF to please give us the money to buy a mirror, and the mirror was the other half of a longitudinally cut mirror that is in Australia. So, the other half of that blank is the 2.4-meter at Mount Stromlo. And we got the money. We got Frank Melsheimer to build the telescope, and we got an optician in Tucson to do the mirror. Matt Johns was the Project Manager. We got all that stuff put together, and it was pretty disappointing because the mirror had not been tested properly, and wasn't really right. That was the point where I got the offer from Harvard, so I didn't fix it. Paul Schechter fixed it. Paul was a math major. There's a classic test, you put a mask with apertures on the mirror, and you look at the in-focus and out of focus images, and you calculate what the figure must be to produce the pattern that you see. Very good, Paul. So, he did that and showed that the mirror needed work. We're not going to send it back to the same guy, whose name eludes me. Is that a coincidence? Anyway, they sent it back to Optical Sciences at the University of Arizona. So, the good thing was we got it built. The bad thing was I did not do a good enough job on supervising the testing. 

Zierler:

What was the issue?

Kirshner:

We trusted the guy to just do a good job. Well, it's probably spherical aberration. It's the usual thing. I don't remember. You could ask Paul. He knows, because he got it fixed. I don't know. I just knew it didn't work very well. So, I liked it at Michigan. I had some good students. 

Zierler:

When did you become chair?

Kirshner:

Oh, pretty fast. Al wanted to retire, I guess, and there weren't very many other plausible candidates. Like, none. So, I became the chair, and the observatory director, and full professor, all that stuff, in the early eighties. So, I was thirty-two or thirty-three. A billion seconds old, roughly speaking. Which is pretty young for that kind of responsibility. And Michigan had been in a decline, I would say, since Leo Goldberg had left, and he went to Harvard. I kept following him around, inadvertently. 

Zierler:

Did Harvard recruit you, or were you looking for your own exit strategy?

Kirshner:

They recruited me. I got a postcard from Bill Liller, who was one of the people I had taken a course from. It said, "Bob, many of us are hoping you will come here." And I thought, I have no idea what they're talking about. Harvard operates in a mysterious way. They don't talk to you. They create a list of possible (or impossible) candidates. If the department wants to hire someone from that list, based on 20 or 30 outside letters, you go to the President. There's a hearing, the ad hoc committee, to see whether this person is truly worthy. But Harvard had had a terrible time trying to hire an observational astronomer. They tried to hire my advisor, Bev Oke. He didn't want to go. Wal Sargent: he didn't want to go. They were at Caltech and had the best telescope in the world. But Harvard was rebuilding Astronomy. They were reinventing the place. George Field had become the director; Riccardo Giacconi was hired. They had hired a bunch of people because the department had fallen into disrepair. Bill Press was on the faculty. You don't know all this secret work is underway. And then they call you up and say -- it was Bill Press who called. He likes to do that kind of thing. I have the feeling this was in the interregnum after Derek Bok stepped down and Henry Rosovsky was the acting president.

Anyway, Bill alluded to the dean and the president, it was all confusing to me. Anyway, Bill said, "We'd like you to come." And I said, "Oh." You want to say, "No. I don't care about that." But, I said, "Well, I'll come and talk to the dean." Oh, yeah, Mike Spence, who later won the Nobel Prize in economics. It's not really a Nobel Prize, but you know, in honor of Nobel. And I spoke to him, and it was summer. Yeah, I guess I'd gone back to New England for a summer visit. Gee, it was nice. Well, then, I went around and talked to people in the department, and they had built the multi-mirror telescope by that time. They were on the cusp of getting that working properly. So, that was good. There was a big telescope, and John Huchra was there, who had been my pal in graduate school. And then, there were all the people who had been there when I was an undergraduate. It was sort of funny. 

Zierler:

Bob, was this switch an opportunity for you to take on new projects, or did you essentially transfer your research agenda with you when you went back to Harvard?

Kirshner:

I pretty much brought it with me -- the cosmological things I had been working on were redshift surveys with Paul Schechter, and Steve Shectman, and Gus Omler. Those guys invented almost all the stuff that was used for the Sloan Digital Sky Survey. Or at least, they brought it to practice. Roger Angel had a lot of ideas, too. And we had these plug plates that we were using on the 100-inch at Las Campanas, and we spent many, many nights getting redshifts for thousands of galaxies. Huchra and Margaret Geller had been doing galaxy redshifts one at a time with the 60-inch telescope, which was a feat of perseverance. John is a very persevering person. But we were doing it one hundred times as fast. So, we caught up pretty fast.

But the Sloan Digital Sky Survey was getting organized, and they were going to do it all the time, better than us. And at some point, we saw the headlights in the rearview mirror and thought we'll stop doing this. We should not have quit, because Sloan was still four years from really getting any data. But we discovered a lot of the stuff that was important. What's the biggest scale of structures, the biggest voids, and the biggest walls, and all that stuff? I'll tell you, Margaret Geller told me that when she read the Boötes void paper -- well, they not only said it. They wrote a nice review article in Science in the middle of what they were doing, and it basically said, "Well, we didn't believe it, the Boötes void, and so that's why we did the redshifts here, to show that those guys were wrong." Well, turns out, then they saw the big wall, and there are plenty of voids and walls go around. So, that was an interesting thing. That was cosmology because it has to do with the origin of structure, and what is the dark matter? And so on.

And I'll tell you, if you take these big surveys, you get the average number of galaxies per volume. If you know what the ratio of mass to light is for galaxies, which you could get from galaxy clusters, you get a value for omega matter, which is about 0.3. So, then I was in the game with the cosmology crowd, who said, "Oh, Bobby. That's not right. It's 1. If it's smaller than 1, it gets smaller. If it's bigger than 1, terrible things will happen. It's got to be 1. Omega is 1. Space is flat." I said, "Well, okay, yeah. Well, we get 0.3." So, it was sort of like talking to Sandage. They really get close, and lean in, and berate you for doing this so badly. That's what they'd say. "This is very difficult, isn't it?" "Oh yes," I'd say, "this is very difficult." And you have to make some assumptions. You have to assume those galaxies are like the other galaxies, which they are. Anyway, that was really interesting. So, I had Hubble constant measurements from the expanding photosphere method. I had the omega matter from the redshift surveys. So, I went to all the cosmology meetings and made myself -- I wouldn't say unpopular, but you know. I was not toeing the party line. I thought, well, this is what the data seemed to show. So, you learned to talk in that sort of subjunctive way. 

Zierler:

Bob, were you dual hatted when you took over as head of Optical Infrared at the Harvard Smithsonian Center? Was that a joint appointment with astronomy, or did you switch over?

Kirshner:

I don't even know what you're saying. I was a Professor of Astronomy at Harvard, and the Harvard Smithsonian Center for Astrophysics is a joint enterprise of Harvard and Smithsonian. So, when I was head of the Optical and Infrared division, I had a courtesy appointment with the Smithsonian. I think I could go into the museum free. Oh, everyone could go into the museums free. Well, anyway. No. Look, you are treading into an area where only the natives know how to avoid the quicksand. The relationship between Harvard and Smithsonian; what is the CFA; what kind of appointment do you have; who pays you? Outsiders just never get it right. I can help you if you wish, but it's not worth your time. You want to talk about it?

Zierler:

No. I mean, so it wasn't a big deal for you, in terms of the politics or what you were working on?

Kirshner:

No, nothing. Except, I now had 150 people that reported to me. And I had to deal with the civil service. The observatory staff are Smithsonian employees, and they're on the civil service, and there's a whole evaluation thing, and there are bonuses, which everybody expected to get, but offended everyone. That part was hard, but the observatory part was not hard because the observatory -- it didn't exactly run itself, but it ran very well. It wasn't that demanding to make sure that was happening. But I did get a threatening letter. That was good. There was a developer in the valley on the way to Mount Hopkins, south of Tucson. They'd gotten some approval, and the place was zoned for four acre ranches. Little ranches. The developer went back to the board and said, "No, I'd like to make them one-acre zoning." Four times as many houses; four times as much light. In some public setting I said, "Well, that would not be good for the observatory." So, I got a bombastic letter from lawyers for the developer who said, "You, sir, under the Constitution of the United States and the Fourth Amendment, this constitutes a taking of my property by the Federal Government. We are going to sue you for $90 million." And I said to myself, well, you're not going to get $90 million from me. I know powers of ten. If they had said we're going to sue you for $9,000, well, I wouldn't have worried too much about that. $90,000, I'd have worried plenty. $900,000, I'd have been terrified. $9 million, not that much. $90 million, you must be joking. So, it's useful to understand powers of ten.

And at that time, the head of the Smithsonian had been the General Counsel at the Department of the Interior. So, Irwin Shapiro, who was the director, took this case to him. He opined, "This is bullshit." Oh, that was good. I didn't worry after that. So, this is why powers of ten are useful, and also why being the observatory director was amusing in a way. The big thing I did was to help get Harvard the Magellan telescopes. There, it was a matter of money. We had been talking with the University of Cambridge -- Martin Rees and his crew, and Richard Ellis and those guys -- about building a 4-meter telescope of our own in Chile. We were going to have the Cambridge-Cambridge telescope. Good thing we didn't, I would say, but anyway, we went around and tried to get people to help us. Dr. Sackler was one of the people we got some help from, but not much. But inside Harvard, there were rules about who you can ask, and under what circumstances. It turned out that for reasons too arcane to pursue, Landon Clay, who was one of the founders of Eaton Vance, one of the big mutual funds, and a Harvard alumnus, was mad at Harvard about some aspect of their investments, I guess. So, they said, "Well, look, if you can get this guy to help you, okay." And in the end, he did. You know, it's the Clay Telescope. He gave us a lot of money to be partners with Carnegie to build the second telescope of the Magellan Twin Telescopes. Our Carnegie friends had been very clever. When they built the first telescope, they dug foundations for two.

Anyway, so that was how we got to be partners. I took Landon and his family around in Chile, and we went to the site, which is very impressive because it's pretty far from anything, and it's very dark, and the southern sky is striking. Anyway, so that all worked as it's supposed to for that scale. But that's tens of millions. GMT and beyond is a bigger scale. I was on the board for that when we got going, and Harvard is a member of the GMT, but that's a much taller mountain to climb (metaphorically). The other US-led telescope at that scale is the TMT, the 30-meter telescope. And the biggest funder engaged in supporting the TMT is the Gordon and Betty Moore Foundation. Gordon Moore was really interested in the Keck Telescope, and Jerry Nelson, the designer. Gordon was persuaded that he ought to get the next thing started. And he did, and he gave them about $50 million to get going and do the design work. And the foundation has pledged $200 million, and we haven't paid it all out yet. That is about -- I have 12 seconds out of every minute for science. I have about 40 seconds out of every minute for the TMT. It's very time consuming, and as you know, the problems are not principally scientific or technical. They have to do with, really, anthropology, with political permission and legal matters. We've been to the Hawaii Supreme Court twice, and won. It's a much more complicated thing. When you have astronomers in charge of a political and social activity, you need help. So, anyway, we're still working on that, as you know. It's hanging by a thread, really. We're waiting for the Astro2020 decadal review to see where it comes out on the recommendation for big projects. If the big telescopes come out on top, then NSF will probably do something here. 

Zierler:

Bob, were you in touch with Nick Suntzeff before high-z supernova, or was that only as a result of his discussions with Brian Schmidt?

Kirshner:

No, no, I knew Nick, because I had been going to Tololo all the time. 

Zierler:

When did you get involved in the collaboration? Was it right from the beginning?

Kirshner:

Well, Brian finished his thesis on expanding photospheres and the Hubble constant. By the way, we got seventy-two. Good luck, huh? No one cites it except us. That's one of my rules. Always cite your own papers, because if you don't, who will? Brian was awarded a post-doc at the Center for Astrophysics. Kind of unusual. Usually, we like to get the birds to fly out of the nest, but he and Jenny were getting married, and she was finishing her PhD in economics at Harvard. Anyway, they wanted to stay. So, Brian went down to Chile. They had some data from the Calán/Tololo Supernova search, and the subsequent photometry and spectra on type II, because we wanted to do more of that if we could. And I think that's when he and Nick and Mark talked more specifically about doing cosmology with supernovae.

Now, I had been, for many years, on the visiting committee for the Center for Particle Astrophysics at Berkeley. So, I knew all about what those guys were doing. Well, there were two parts to it. One was, I thought they were doing it very badly. I've got to be fair. They did a good job on developing the techniques for finding supernovae. But their measurements of the supernova brightness were wrong in principle, and they didn't know anything about photometry. It just was bad. So, I was on this committee -- also, they were imperious, I guess, is the right word, in the funniest way. When they found a supernova, they'd call you up. One night I was on the MMT. They called me up and said, "We've got a supernova. Can you observe it?" I said, "Well, sure. I understand what you're doing. It sounds interesting." So, I took the spectrum, and it was a type I supernova. That was good, so I sent them the spectrum.

And then I went to one of these committee meetings a few months later, and they gave me a report on what they'd been doing. They said, "Here is our best spectrum of a Type Ia supernova." Hey! That was my spectrum! So, they just didn't understand the culture, which is, if you ask somebody to do something for you, you would then naturally ask them, is there something I can do for you when I'm observing? Or if you give somebody data, they would acknowledge that this data was taken by a helpful collaborator, and they might even put you on the paper. Well, we would always put them on the paper, and we would always pay people back if we could. But that was not their approach. So, well, anyway, I knew all about what they were doing. That's for sure. When you tell people you really should be doing this this way or that way, they take it as personal criticism. So, that wasn't all easy. But you could see the result when they had their first cosmological result --in 1997 in the Astrophysical Journal. It's wrong. You know, it's wrong. It says the universe is not accelerating and models of that kind are ruled out. Okay. Uh, okay. That's what they concluded in 1997. So, I thought there was room for improvement in techniques of measurement-- that's photometry, basically.

And Nick is the master of this. Nick -- I think I say it in my book. He's sort of like Eeyore. Everything's terrible, and oh my goodness, you're not doing this and you're not -- so, what that means is, if Nick says, "This is okay." It's really okay. It's really good. So, they'd been doing this Calán/Tololo thing, and their intention was to start at low redshift and move out, which is clearly the intelligent way to do it. You learn about the supernovae; you learn that there's a relation between luminosity and light curve shape. All of that stuff. They showed all that. The technique for searching for supernovae, of course, was done by the Danish at ESO, where they took digital images and subtracted them to discover supernovae. So, all of that was kind of known, and I saw that the Berkeley guys were struggling. They weren't very forthcoming. They did ask us; would we join them? And I thought, this is not a team I want to be on. So, that's the point at which we decided we would do it ourselves. And the problem was, of course, they'd put six man-years into developing the software, for doing the image subtraction. So, this is where Brian said to me, "Oh, yeah, I think I could do it in a month." I said, "Okay, go ahead. Why don't you?" And he did. He wrote a pretty buggy software. It didn't really work all the time, and only worked on one computer. Anyway, there were some things about it that needed improvement but I put all my financial support, my NSF grant, I used all that for travel and the computers and everything to help us go forward on that. 

Zierler:

Bob, at what point in the collaboration do you realize this is Nobel Prize winning work at some point? When does that happen?

Kirshner:

Oh, the Berkeley guys kept saying that from day one. But they were obsessed with that stuff. And it was Rich Muller's idea to do this, and it was going nowhere until Saul joined that group.

Zierler:

When did you get in contact with Saul? When were you working with him?

Kirshner:

Well, there was a visiting committee for the Center for Particle Astrophysics. That must have been '92, '93, '94, '95. All in there. It's just when they were getting going. They didn't know anything about the Danish supernova search. Well, I said, you know, people who are not you have done this stuff before. And the program of using supernovae to pin down the Hubble constant and distant supernovae to looking for curvature in Hubble relation that means cosmic acceleration or cosmic deceleration. Tammann gave a talk in 1979 at the Space Telescope Science Symposium that was at the Institute for Advanced Study, and he worked out on the back of an envelope how many supernovae you'd have to measure in order to get some indication of whether the universe was expanding at a constant rate or slowing down the way all the theorists insisted it must be. And the answer was of order ten. So, that sounded pretty good. Stirling Colgate had built an automated searching telescope, and so on. Anyway, there was a who literature on this but they didn't pay much attention to what other people had done. 

Zierler:

Bob, there's a whole side story here with Ray Orbach, and the DOE getting involved in supporting astrophysics. Did you contribute in any way to making that pitch? 

Kirshner:

Not consciously. 

Zierler:

Because, of course, this is more naturally an NSF domain. 

Kirshner:

Well, yeah, but if you want to know about particles and fields, we've got some fields, we've got some particles. We've got a lot of them. We've got too many fields. 

Zierler:

Yeah. So, beyond the Berkeley guys, as you say, they thought this was such a big deal from day one. For you, when did that happen?

Kirshner:

Well, anybody could do the arithmetic. Tammann had done it more than ten years earlier. It was clear that this was a way to do it, and the only thing that mattered was could you correct for the variation in luminosity of the supernovae well enough to do it, and could you recognize when the supernova was dimmed by dust? That could fool you, and you would think it was farther away. We worked on those problems, and we did it. So, I would say, it's a mistake to think that this was invented at LBL, but -- actually, no, it's not a mistake. They did invent it, but they were not the first to invent it. You know? This was an ongoing thing in the community. We all knew this. So, did I have an "aha moment"? No. We knew we could do it. 

Zierler:

So, if you didn't have an "Aha moment," obviously there's this buzz that starts, that ultimately it ends with the Nobel and a slew of other prizes. So, if you're downplaying the internal appreciation for this, when did you get a sense that the larger award community, the larger scientific community, was treating this as the very big deal that it was?

Kirshner:

Well, it's always a mistake to focus on awards. The thing is to focus on the work, and if you can do the work, because you can solve the technical problems of finding the supernovae, you can solve the coordination problem of being able to get the telescope time at the right time, and do all the measurements. That's the rewarding thing. But, okay, but --

Zierler:

That's the science question. I'm asking more the sociology of science question. 

Kirshner:

Yeah. Well, the particle astrophysics community was looking inside the particle astrophysics community for answers to the question of cosmic deceleration. So, you know, Rocky Kolb, or Mike Turner, they were looking to Berkeley for the answer. And I said, "Well, you know, we're actually doing this stuff. It takes a while to publish it, but it's going pretty well." There was a meeting in Cleveland, and -- I've forgotten exactly when. Anyway, it was a cosmology meeting in Cleveland, that Lawrence Krauss had organized at Case Western Reserve, and we were all going through a door to go to the next lecture hall, and Gerson Goldhaber, who was one of the Berkeley guys, and I, were headed to the door, and I pulled it open for him, and I said, "Well, Gerson, we're right behind you." And he said, "Eh, a few years." And, well, in fact, we already had quite a few supernovae and follow-up observations, that we were really right behind them. So, I think, they were surprised by how fast we caught up. And it was because Brian did the software so fast, and we knew what we were doing on the observing side, so that we wasted very little time. We were better at calibrating the space telescope data because we had done that before.

So, there were a lot of things where we had experience that was relevant. But your question is the sociology one. I'm trying to think. Well, we were going to all the meetings, and it was pretty clear that this was important if you could do it. And the LBL crew thought it was important, and they had a result, which was that the universe is slowing down. I thought, boy, this makes it harder because that wasn't what our data was showing, and I didn't want to say anything. I just wanted to see if our data stood the test of more data. So, then, you had the question of how much is enough, and when do you say something? And Adam is good at this, Adam Riess. He had been my graduate student and he went to Berkeley Astronomy as a Miller Fellow. He was doing the work the analysis of what you could infer about cosmology from the first handful of our supernovae? I remember very clearly when he called me up and he said, "You know, I keep getting negative mass." And I said, "Well, that's not good. You must have forgotten something. Square root of pi, something like that?" Because we knew what it meant.

I tell you, the other thing that I was less conscious of than I should have been was, of course, the Steinhardt and Ostriker paper, and there was another one by Mike Bolte and Craig Hogan that paid a lot of attention to the age of the universe. Both of them said you can have a flat universe, a Hubble constant of seventy, but you'd need to have two thirds of the universe in a cosmological constant, or something just like it. Which turned out to be quite prescient. So, I think it was in the air, for sure, that you could make this measurement. And it was clear you could do this problem-- the difference between a decelerating universe and a coasting universe at a redshift of a half is about twenty percent in brightness. So, if you could make it so each supernova was good to twenty percent, let's say, and get ten of them, that's a 3-sigma measurement. So, it was pretty clear you could do it. Then, in the late nineties, the best cameras were at the national observatories, which was great, but that meant we were both applying for them. And the best telescope to follow-up, of course, is Keck, and we were both applying for that. So, there was a lot of competition-- and the same with the Hubble Space Telescope! The time allocation committees felt like they were having to cut the baby in half. Allocation of the resources was a hard problem.

Zierler:

Bob, I know you're not supposed to read too much into titles. Maybe publishers have more say in this than they should. I'm curious, why The Extravagant Universe? Why not simply The Accelerating Universe?

Kirshner:

Too many parts. Who needed it? How come we have dark energy? I don't know. Do we need this? You know, it's just like too much. 

Zierler:

So, "extravagant" is a catch-all.

Kirshner:

Yeah. Too much. Too many parts. If we understood it better, we would know that it's just enough parts. But we don't understand it very well, do we?

Zierler:

Was the motivation from the beginning to make this a popular book? You wanted to get this message out to as many people as possible?

Kirshner:

Oh, yeah. And again, I don't want to exaggerate, but LBL has a very good publicity machine, and they asserted that they invented this method, and we adopted their techniques and confirmed their result. I thought was interesting because their publication in '97 showed the universe is slowing down and the methods had been spelled out by the Danish group. Our publication was submitted in '98, and our paper came out before theirs was even submitted, and published in '99. Now, you know, to some people, in a 13.7 billion year old universe, what difference does it make? Plus, they don't care who found it anyway. But I've always found that getting the record straight is important, and I learned it a lot by writing the book. I had very clear memories of lots of things, and I wrote up a manuscript, based on those very clear memories, and it was all correct as far as I knew. And then I sent it around our research team, the High-Z Team, and many people said, "Oh, no. That's not how it happened." So, I learned about the perils of relying on memory, oral evidence. The written evidence and the documents are really important. That's the difference between journalism and history, right? The weight of a document.

Now, this book was meant to be a popular book, yeah. Popular-level book, as we say. But I also wanted to get our side of the story out, because I thought that -- well, I saw that there had been a lot of effort to paint it in a different way. This work had its roots in a paper Charlie Kowal wrote in 1968 on measuring Hubble constant from supernovae. We've been working on this for decades. The search techniques had been done by a Danish group that wanted to do exactly this problem, but their telescope was too small, and their chip was too small, which meant the rate of discovery was too low. One a year. You can't do it at one a year. One a month, okay. One a year, just not enough. So, this was part of a long arc. It didn't just suddenly happen. And it's something where the guys at Cerro Tololo and my group at the CFA had been working on supernovae, studying how to get the luminosities from the light curves and the spectra, how to correct for the reddening, how to do all that stuff. So, it's like the field came to us, and that was really great.

Zierler:

When did you start to become involved on the speaker circuit, really becoming a popularizer of science?

Kirshner:

I don't really remember exactly, but I've always been good at that. I taught big classes for undergraduates, and if you've got a really interesting result, and you're a good speaker, you get invited to do a lot of invited talks, and the dean's lecture, and this and that. But I also used Jodi Solomon in Boston, who's an agent, who helps get the word out. Oh, the dog is speaking up. 

Zierler:

Hey, that's not bad. 

Kirshner:

It's time for lunch for him. I guess, for me too. I'm just getting warmed up. You want to see him?

Zierler:

Sure. 

Kirshner:

Sure, you want to see him. Just a minute. Alright, just a minute. We're going to switch into reality here. Yes, yes, yes. There he is. So, this is Cosmo. Where'd you get that name? Cosmo is a miniature bull terrier, and he's six months old, and he's hungry. He wants to have his lunch. 

Zierler:

Aww. 

Kirshner:

So, what can I do for you?

Zierler:

Oh, we're getting there. We're almost there. Bob, what emotions were swirling around when the announcement came out and you realized not one, but two of your students would be getting the Nobel?

Kirshner:

Well, as I told you before we started, I had a conversation with Frank Wilczek the day before. Everybody knows which day the physics prize is coming out, and I thought -- I knew there had been a pattern of technological things one year, and theoretical things that had been demonstrated another, and experimental things the next. And I thought, it's probably our turn. So, I got up that morning at whatever time it was -- Frank Wilczek has a very good story on that. I can't tell time. What kind of professor is that? Theoretical. Anyway, I got up at the right time in Sweden and tuned into the announcement. They start talking in Swedish, but they had the pictures up, so I knew that Saul and Adam and Brian had been awarded the prize. So, that's when I knew. But it was pretty clear that's the way it was going to break down, because some of the other prizes had been adjudicated that way. It created a lot of trouble inside our collaboration. Adam and Brian were adamant that these prizes ought to be given to everyone, and we were able to do that with one of them. Anyway, some of the prizes were done that way. But you know, the Nobel Prize, you can cut it in half, and you can cut one of the halves in half, and that's it. So, there's just not that much room on the podium, and was the way it sorted out. 

Zierler:

I'll just note editorially that obviously this is a relic of the nineteenth century, when one person could really be responsible for a major scientific discovery. 

Kirshner:

Yeah, yeah. And there was some commentary after the prize. Martin Rees wrote a thing saying, well, you know, that Swedish group, they don't really know how to handle this. 

Zierler:

To what extent do you see the Breakthrough Prize as a corrective to that, a twenty-first century solution?

Kirshner:

It created a lot of work for the Breakthrough Prize staff to give certificates and pins and moderate-sized checks to everybody!

Zierler:

Bob, last question, as we bring the narrative up to the present, before I ask just a few retrospective questions. That is, we talked about your work at the Moore Foundation presently, but what were the considerations? I mean, it was a big deal for you to move. 

Kirshner:

Were you in Boston in 2014?

Zierler:

No. 

Kirshner:

There was about forty-seven feet of snow in Boston in the winter of 2014-'15. I was teaching my big class, and my wife said, "You know, we really should go someplace on spring break." And I said, "Oh, yeah, well I'm too busy." And she said, "No, no, we really should go someplace. Let's go to Santa Barbara. We always like to go to Santa Barbara," where I'd been to the KITP several times. So, we were planning to go to California during spring break, and when they called me up -- who called me up? I don't know. Was it the recruiter? I forget. And they said, "Would you be interested in this job?" I said, "Eh, who are you kidding? I am the Clowes Professor, and I now have the corner office, after several years of careful office management." I had the best office in the building. So, I thought, no, no, no. But, you know, it was winter, and we were going to California anyway. So, we went to California, and I took one day out of that, to visit in Palo Alto, and I saw Harvey Fineberg. Well, Harvey had been the provost at Harvard when I was on the faculty, before he went to the Institute of Medicine, now the National Academy of Medicine. It's his great achievement, changing the name. You don't really know the provost at a university, unless you’re in deep trouble but I did know him socially. He's a very nice person, and every time I went to a National Academy meeting, which was most years, I'd see him and shake his hand and say hello. So, when I went to the office of the Moore Foundation, I kind of knew him. And he said, "Oh, boy. I'm so glad you came." And I said, "You know, it's mostly, I was going to be in California anyway, and I was kind of curious about the Moore Foundation." So, to get to the point, I said, "Harvey, why would I do this?" He said, "Well, you know, at Harvard, you've done research and teaching, and you have climbed that mountain. Here's a different mountain. We'll have some fun, and we'll do some good. What do you say?" I thought, oh, different mountain. Oh, that's a good idea. So, anyway, so we did. 

Zierler:

Did you see the high-z as -- not a capstone. You're not done, by any means, but without high-z, would you have felt a certain completion in the full-time research aspect of your career up to that point?

Kirshner:

Let me tell you a story. At the Nobel ceremonies, there are a lot of things. There's a colloquium, and there are discussions, and there's this, and there's that, and there's a very nice reception at the Nordic Museum. So, we're there at the reception at the Nordic Museum. Meanwhile, kids are chasing after -- I mean, graduate students -- the students are chasing after Brian and Adam to get their picture taken with them. And the head of the physics selection committee came over to me and said, "Hello." I said, "Hello." He said, "I am the head of the selection committee, and I've read your book." I thought, oh, that's good, I guess. He looked at me with sad eyes and said, "You'll just have to do something else." And I thought, jeez. I'm not going to live that long. So, you know, the answer is yeah, sort of. That's right. The project I'm working on right now, as I mentioned, is the infrared incarnation of doing distances to supernovae, which is going to be the future of supernova cosmology. I couldn't get the DOE to support me for this, by the way, and it's a good thing. Anyway, yeah, no, you got it right. That's the psychological part of it. I mean, I'm not going to do anything better than that. 

Zierler:

What's been most enjoyable to you, to be in this really special position to decide what basic science gets supported, or to help make those decisions?

Kirshner:

Well, it's the same motivation as being a faculty advisor. You're helping other people do their work, only it's not graduate students and apprenticeship. It's your peers, and you get the pleasure of helping them achieve their goals. For a lot of our grants, I understand very well what the goal is even when I am not master of all the deails. Not all the grantees are people I know, but a lot of them I kind of know. I'll tell you a funny story, though. Shep Doeleman, at the CFA, is somebody I really didn't know. He was already a grantee of the Moore Foundation when I got to Palo Alto. So, I went with the program officer to visit -- to my own place, I went to an office I had never been to, and I met a person I had never met. CFA is pretty big. And we talked about the Event Horizon Telescope, and how the data system that we were helping them build was going to enable them to make images of black holes at the center of the galaxies. And I thought, wow, I've come to the right place. The Foundation already found that great project without me. That's good. But, you know, that's another example where it's $1 billion worth of telescopes. We put in a couple of million dollars into the data systems. Very unglamorous stuff, but it makes all the difference. It wasn't me, but people at the foundation had selected Shep, and had invested in this. And well, that's a great discovery and a great technical achievement. Underneath the hood is the stuff that we really helped with. So, that's a good story. 

Zierler:

Bob, I'll reward your puppy's patience to get to lunch, so I'll go right to my last question. Let's look to the future, and let's bring it right back to the very beginning of our conversation, where there's this understanding that observation is really leading the field in cosmology. On that basis, using your powers of extrapolation, what are you most optimistic about in terms of observational breakthroughs that really might get us in the next -- let's say short term, five years, ten years, for what we understand about the universe that we don't currently understand?

Kirshner:

Well, James Webb Space Telescope is going to get launched. Will it unfold? I hope so. That's going to be a way to see beyond redshift 10. 

Zierler:

What's the big deal about that?

Kirshner:

Well, there was a time when the universe was just amorphous; had a power spectrum of fluctuations, but how did those first stars and quasars get formed? How did the universe get ionized? Everybody knows that the CMB properties are set by recombination of Hydrogen, but did you know the universe is ionized? Well, that means, it got un-recombined. And that was done by ionizing sources, and those sources are not known. So, if you want to know, how the universe get to its present state, you've got to know that. If you want to know how blackholes -- why do blackholes have the masses they do? Why do galaxies have blackholes in them? All of that stuff, which to the theoretical physicist, that's like, well, I don't know. You're trying to predict the weather, or something. But this unfolding from simplicity, super-duper simplicity of the Big Bang into complexity, and richness, and the ability through nuclear reactions, to make the chemical elements, to make my parents and so on, that we were discussing earlier. All of that happened in an unseen time and place. So, there's a huge amount we don't know, and we're just on the cusp of measuring these Dark Ages sorts of things, partly through the Infrared Space Telescope, which is a fantastic thing; partly through these radio measurements of the 21-centimeter. It's the first objects forming from the undifferentiated haze. This question of how richness and complexity came out of simplicity is really interesting. You know, we all have a personal stake in it, because that's why we're here. So, that's a little short of the absolute fundamental physics story, and maybe the physicists will lose interest in cosmology. But I think, as a subject, it's going to great in the coming years. That, plus when LIGO gets better mirrors and works ten times as well, that's going to be better, too. 

Zierler:

Well, Bob, we can break for lunch. How about that?

Kirshner:

Yeah, let's break for lunch. Thank you. It's been a lot of fun. 

Zierler:

It's been great, Bob. Thank you so much for doing this.