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Interview of Lyman Spitzer by David DeVorkin on 1978 May 10, Niels Bohr Library & Archives, American Institute of Physics, College Park, MD USA, www.aip.org/history-programs/niels-bohr-library/oral-histories/4901-2
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Early life and family origins; Phillips Andover Academy; teachers; Andover and Max Millikan; early interest in astronomy; methodology of science; undergraduate years at Yale University; hobbies, teachers at Yale; physics and Alan Waterman; interest in particle accelerator; extracurricular study group at Yale; interest in economics; Henry Fellowship at University of Cambridge; concentration in theoretical physics; studies with Arthur Eddington. Graduate work at Princeton, Henry Norris Russell, thesis, origins of solar system, spectra of M giants; faculty position at Yale; World War II work; return to Yale; move to Princeton, Martin Schwarzschild, conditions for research at Princeton; space research; Stellerator Program; Jesse Greenstein's Committee; Astronomy Missions Board. Work on planetary filaments; postdoctoral years at Havard University, 1938-1939; positions at Yale; work on underwater sound during World War II; interests in galactic evolution; stellar evolution; Walter Baade's Populations; interstellar medium; growth and activity of Princeton astronomy; Plasma Physics Group, rocketry; Copernicus satellite; large space telescope; funding; responses to specific questions in astronomy and cosmology. Also prominently mentioned are: Frederick M. Boyce, Subrahmanyan Chandrasekhar, Fred Hoyle, Raymond Lyttleton, Frank Schlesinger, Harlow Shapley, John Q. Stewart; and National Academy of Sciences (U.S.) Greenstein Committee.
We are going to go over some material that was erased from the original interview (#1) last year. We’ve been talking for a moment about your work on planetary filaments. Shall we talk about that first?
Was this Before Harvard?
Well, I think it goes with Harvard. I'm not so sure I started on this at Harvard, but I'd been interested in the problem of the origin of the solar system when I was a graduate student at Princeton. H.N. Russell of course had been interested in the problem, and I'm sure I discussed this on various occasions with him. I believe that we discussed these problems also in some meetings that Bart Bok arranged for graduate students at his home. I think it was once a week, perhaps Sunday evening, where we discussed a number of active scientific problems.
When you were at Harvard?
When I was at Harvard, yes. I was thinking about the general problem of how a filament torn out of the sun by tidal attraction of a passing star, as in the Chamberlin-Moulton theory, for example, might condense into planets. I thought it over, trying to visualize what would happen. It seemed to me more likely to expand from the high pressure, due to its own high temperature, than it was to collapse into stars. So I undertook some analysis to develop the idea, and found in a few days, I remember, that in fact, that's exactly what would happen, and that the cooling process, which is one way that expansion might be averted, was in fact very much slower than the process of expansion, and so I wrote it up as a brief paper and sent it off to the ApJ.
I believe that's one of the quickest papers I've ever written, because it was just one central idea, which I had before I really started to put anything much down on paper. And the theory verified the idea, with quantitative analysis, using very simple mathematics. So it was not difficult to finish up the work and write the paper.
To your recollection, when you wrote the rough draft, did you show it to anyone at Harvard, discuss it with anyone?
I'm pretty certain I did. I probably sent it to Russell for his comments, although I don't remember specifically doing so. As a matter of fact, I think I looked through my files for a letter m Russell on that subject, but I don't remember whether I found or not. If I did I'm sure I would have given it to you. I guess I didn't.
It's certainly something we can look at in Russell's collection itself. I haven't looked that late in his collection.
Now, it's possible that I didn't, but certainly my policy then as I remember it and as it is now, is to circulate a draft around to anybody who's sufficiently interested to read it critically. For one thing, people are more likely to read a paper carefully when it's in draft than they are after it's come out in the ASTROPHYSICAL JOURNAL.
And that's when it's important to read it.
You did have some contact with R.A. Lyttleton when you were at Princeton, is that right?
Yes. That's correct. Lyttleton was here, and Lyttleton and Russell and I had a number of discussions on problems of the origin of the solar system. I'm sure that it was as a result in part of those discussions that I became interested in this problem.
That's quite interesting. I know you've maintained contact with many physicists, such as Lyttleton, through the years, but can you remember what kind of a person he was back then in the thirties, when he was still working with Milne? Did he ever talk of Milne? Did you get a feeling for the way he did science, and that there was any difference? You'd been in Britain yourself, of course. Was there anything different in the way he was thinking about things?
Well, Milne's way of thinking certainly was very different from that which I admired so much in the case of Sir Arthur Eddington. My own manner of thinking was closer to Eddington's than it was to Milne's. I've never been able to understand the way Milne's mind worked. He did very fine work, a great man, but he didn't think the same way that Eddington did. His papers at least, when you read them, seem more mathematical. They don't present the basic physical ideas in the way that gives rise to an intuitive understanding directly.
But did Lyttleton seem to continue this, or was he more physically oriented?
I don't think he was perhaps as extremely fond of the mathematical end as Milne was. But I don't remember him being so far to the other end either. I don't have very vivid memories of him, although I have seen him since. I had lunch with him just a couple of years ago when I was in England. We have very friendly relations. He has interesting ideas on comets these days.
Yes. He's had for quite some time. Concerning the work on filaments, do you recall what kind of reaction you got from people after it was published? Was there any public reaction to your work?
There was quite a bit of interest, more than most papers that I have written. The problem of the origin of the solar system is of great popular interest, of course, and my paper did effectively dispose of one type of theory, and so it had a certain amount of attention, yes. I think it had more attention than it might otherwise have had because of Russell's summary of it, I think in the SCIENTIFIC AMERICAN. He wrote a regular column.
Did you have any reaction from the supporters of the Chamberlin-Moulton hypothesis?
Well, if I did, I don't remember them. They didn't scream bloody murder. I had various correspondence with people for a few years on that subject, but nothing was very profound.
Did it affect your ideas on stellar evolution at all — the idea that gases could expand against gravity?
I don't think so. I had done some thinking in terms of expansion of gases, in connection with my thesis on the M-supergiant star Alpha Orionis.
But there was no clear simple physical idea in that case that was the subject under discussion; I tried to understand observations that I worked into my PhD thesis, and it was clear that gas motions were somehow involved, so I became interested in them, but didn't really get very far.
I recall from last year, we discussed the fact that in your thesis you were still thinking that the Supergiants did evolve directly out of the interstellar medium.
That didn't really come into my thesis. I was thinking of the stars as physical systems and analyzing their properties at the particular moment in time, when they were observed, rather than discussing their origin.
Later on, you did get more interested in pre-Main-Sequence evolution.
Oh yes. That's right. But whether the Supergiants formed first, or whether they appeared later, depended upon which ones you were discussing at the time. If you include among the Supergiants the 0 and B Supergiants, then it's clear that they were formed directly from the interstellar clouds. And that's still the picture. But in our present picture the difference is that shortly after they're formed they get to the Main Sequence, and then finally move over to the Red Supergiant phase. That's an evolutionary sequence that only appeared some years later.
Right, OK. Let's talk about your move to Harvard.
If I remember correctly, my own belief at this time is that these were simply not understood.
Right, OK. Let's talk about your move to Harvard.
How did you get there?
I applied to the National Research Council for a postdoctoral fellowship, and as part of the review procedure, I went to New York to be interviewed by Harlow Shapley, in I think the Harvard Club, or maybe it was the Princeton Club. I was very much impressed by Dr. Shapley, whom I of course had heard of. I may even have seen him before, but I certainly hadn't talked with him in detail. He was very alert, very lively, and a very interested and interesting person. I'd put down that I wished to work under his supervision. He said that would be fine with him. He asked me what I wanted to do. I don't remember now exactly what I told him, or indeed, what I put on my application, but I think I had a number of topics I wanted to work on, that he seemed interested in.
Did you spend all the time at Harvard?
My fellowship was a one year postdoctoral fellowship. I spent it entirely at Harvard, yes.
How did you find the atmosphere for your interests and your general life when you got there? What was the year again?
1938-39. Oh, I found Harvard College Observatory a very stimulating place to work. I came to know a number of people whom I've known on and off ever since. For a while I shared an office with Leo Goldberg, whom I got to know quite well. A few years later, after the war, we offered Leo an associate professorship at Yale to head up the space astronomy effort, or at least join with me in the space astronomy effort, which I was deeply interested in and he also. And while it didn't succeed in launching any space astronomy, at least it had the advantage to astronomy of pushing Michigan into making him the director at Michigan.
So Goldberg was there at Harvard. Was Schwarzschild there?
Schwarzschild was there. I remember well the very deep impression that he made on me, and the various talks that he gave, perhaps as a speaker in colloquia, and his comments after colloquia. He always seemed such an incisive, enthusiastic, clearly organized scientist.
Did you meet him first or first see him at a colloquia?
That, I don't remember. I don't remember when we first met. I just remember being very much impressed by the way he spoke under various circumstances. I didn't know him at all well at Harvard but he made a great impression on me. And from that time on, whenever I had a chance to influence the choice of people I'd work with, I thought of Martin.
That’s an important story that I think we already have from last time. You mentioned meetings at “social seminars” that Bok organized.
Yes, those were very stimulating. It was at one of those seminars that my attention was called to the problem of globular clusters, and how there was no solution possible for the existence of globular clusters within the framework of isothermal gas spheres. It wasn't obvious what might be happening. I was fascinated by the discussion, and we talked about this problem of how one reconciled the existence of globular clusters with the absence of any real physical solution, and what is now regarded as the correct solution of that problem occurred to me. Again I did some work to substantiate it. And this led to another paper, this one in the MONTHLY NOTICES on the evolution of globular clusters. I found out later that Ambartsumian in the Soviet Union had had similar ideas shortly before I had.
Had his been published?
Yes. I forgot where. I looked at his paper. My paper differed somewhat from his but the basic ideas are certainly similar. And his had been published before mine. Yes. But nobody that I talked to had seen it, nor had I.
That's in the tradition of your predecessor here, Henry Norris Russell. He must have had 10 or 15 major papers, breaking new ground, which were either simultaneously done by someone else like Hertzsprung, or just barely anticipated. It started way back when he was a graduate student.
It must be the tradition at Princeton.
I also saw quite a bit of Ted Sterne, who was very active at that time, and Lawrence Aller and of course Donald Menzel, Cecilia Payne, Fred Whipple. All very active.
Now all or many of these people were considered the young stars in astronomy at that time, and through the years too. They were all being governed by Shapley, in a way.
What was the governance like there? How did Shapely run the observatory? How did things get done, to your knowledge?
Well, of course, I was not a member of the observatory staff, so I didn't really get involved so much in the political problems. I do remember discussions with some of the younger staff, were it was clear that Sterne, if I remember correctly, and Goldberg were perceived as being sort of competitors for a tenured position. This is an administrative arrangement which may have advantages, but ever since then I've always objected to that sort of situation, just because it makes for difficult feelings between the members of the younger staff.
Shapley's real scientific leadership was displayed in what are called the Hollow Squares. At colloquia times, the library tables would be arranged as a square, everybody sitting on the outside, Shapley at the center at one end. He would initiate a series of discussions and bring other people into the discussions. And his lively and alert personality and leadership ability to bring other people in made for a very stimulating and very active series of scientific talks with everybody who was there. I found them very interesting and stimulating.
Did this range over all topics in astronomy and astrophysics?
Yes, pretty much so. Of course, Shapley had his own particular specific interests.
What was his participation when matters turned theoretical? Did he remain in the center?
Often times yes. He might make some amusing remark, or point out something that the theorists had ignored, some observational thing or some physical idea. Of course, there wasn't as much complicated astrophysical theory then as there is now. There were mathematical analyses such as the one that Sterne was doing on the rotation of the line of apsides in an elliptical binary system. I don't know whether he did that then or a little later but I think it may have been about that time. But one doesn't discuss the details of such a calculation so much in a public discussion. One states the principles and the results and there's no real discussion of the theory as such.
Actually Russell did start that whole idea of rotation of line apsides.
Oh yes, it was very important, one of his most important. But he had trouble comparing it with the results because he made one approximation which gave him the wrong result, which Sterne and others improved.
I see. Interesting. That was Russell that made the approximation?
Right: That was typical also of him. During that period of time, had Shapely accepted the existence of the interstellar medium? '38, '39 when you were there?
Oh, I think so, although I don't remember those discussions. My real interest in the interstellar medium started a year later when I was at Yale.
So you didn't see any of the controversy that developed over the question of whether it did or did not exist, as a result of your contact with Shapley?
No. At least if I do I don't remember it. I must confess, I'd sort of forgotten that there was such a controversy. Did Shapely deny that there was any interstellar medium?
Even as late as '38, '39?
Well, that I don't know, But in the early thirties, yes.
By the time of Eddington's Bakerian Lectures in 1926 when INTERNAL CONSTITUTION OF THE STARS had come out he discussed interstellar matter. In my earlier book on DIFFUSE MATTER IN SPACE. (Opens book): This is an interleaved copy that the publisher sent me, with lined pages in between each pair of printed pages, and on these I've written all the various later works that have come out that are relevant, so when I'm giving a set of lectures on the subject, I have notes that are essentially up to date. I've done the same thing with my new book which just came out. Very helpful in the way of keeping track of stuff. In here it states that the Bakerian Lecture also is 1926, then.
OK. Had he concluded that the interstellar medium did exist at that time?
Yes, he computed the kinetic temperature and the ionization level of the atoms that were present.
Very good. But Shapely didn't believe that until well into the thirties. He did not believe it, if the history is right, until Trumpler's work on clusters. In the early thirties.
That was 1930 in a LICK OBSERVATORY BULLETIN on clusters. That's where he determined the general extinction. Yes, I make a note here in my book, "As late as 1933, the evidence for general or selective extinction was not conclusive." That refers mostly to the dust. Eddington discussed the calcium atoms, and the interstellar gas was pretty well substantiated by then. The dust component really took about another ten years. By 1935, that was really pretty well established.
Right. It was that dust component that really changed the scale of the galaxy. This is what Shapley was reacting against.
That's perhaps why he objected to it. Yes, he didn't want to accept it until it was really established, but by the early thirties, I think it was just becoming established. By the time I arrived, I'm pretty sure Shapley had accepted the medium.
OK, so when we get to the interstellar medium we can assume that's independent of Shapley's at that point.
OK, anything else from your impressions of Harvard?
It was a magnificently international milieu in which to work. I remember going to a dinner once at the Gaposchkins. Of some 9 or 10 people, I think I was the only native born American there. They were all astronomers at the observatory. Cecelia Payne of course was born in England, Sergei Gaposchkin in Russia, there was Kopal from Czechoslovakia and M. Schwarzschild from Germany, and you could go on and on. A scintillating, lively place.
At that time also, Shapley was promoting this cooperative arrangement between North and South Ireland and the Union of South Africa, to set up, between the three of them, a telescope which they would run jointly. He took the point of view that if he could persuade those three governments to collaborate in something, why, there was still hope that mankind might get together on other problems also. And I think that was probably right. Those are three governments that have many differing points of view.
He certainly had very liberal views at that time. Was that ever discussed amongst you students?
His liberal views came out a little bit later, isn’t that right? At the time of the McCarthy investigation, he was attached as having been soft on Communism and things of that sort. But in 1938-39, I don’t remember him as being any more liberal than anyone else.
That's when Communism was more popular, in the late thirties. I didn't know if he was professing anything at that time or not.
I don't think so. I don't think he was ever actually a Communist sympathizer.
OK. Well, during that year at Harvard you were probably looking for a job.
Yes. And if I remember correctly, I believe I was offered a position with the Harvard Society of Fellows. That's vaguely what I remember. But I was also offered a position at Yale University, as an instructor in physics and astronomy. I guess maybe it was just instructor in physics. The astronomy came later. I owe this in large part, I believe, (this is what they told me), to intercessions by a number of friends at Yale, who approached the physics department and said, "Why don't you make Spitzer an offer?"
In any case I did receive the offer, and I had a long talk with Shapley, and I guess perhaps with Russell also though Shapley was perhaps better at advising young people and had more real knowledge of their problems and more interest in them as people. And he advised me strongly to take the Yale position. It had permanent prospects. It sounds very much like the advice we give our people today, a contrast to what it was like ten years ago, "If you can get a position with permanent prospects, take it, even though there's something that might be more attractive in the next few years." So I took the Yale position.
Who were the friends who interceded?
Well, I had several very close friends, when I was an undergraduate at Yale, also when I went back. One was Max Millikan. Another one was Richard Bissell. And we had a sort of a little series of informal courses we gave. I told you all this in the previous interview.
Yes. That was an interesting discussion — when you learned about economic theory.
That was good. Well, this must have been 1939 that you went to Yale?
Yes. That's correct. I had the princely salary or I think $1700 a year, something like that.
Right. You were married in 1940.
Had you met your future wife at the time of your return to Yale?
I'd known her for years, on and off, but not really very well. She and I were from the same town, Toledo, and my parents knew her parents. But we moved in somewhat different circles, so we hadn't known each other very well. I think I first got to know her while I was a graduate student at Princeton. We both happened to be at my cousin's wedding, and found we very much enjoyed dancing together. She was an archeologist, and returned a few days later to Greece where she spent several years in Corinth working on the excavations there with the American School. We drove back East together. I saw her for a few days and then put her on the boat to go back to Greece. I saw her in the summers, and later on, she visited us in Switzerland in 1938 when I was there with my parents, and then I saw her again in '39. Actually, she was studying and doing some research at Cambridge for a few months while I was at Harvard. I saw something of her there. Then we became engaged in the winter of '39, and married in June of '40.
So you maintained contact over all those years.
The contact really started in '37.
You'd known her previously?
I had known her, yes but not really very well. I knew her at parties but we hadn't really done anything much, didn't go to the same schools.
Has she maintained her professional interests?
Yes. She never got a PhD degree. She stopped that effort we got married. But she's still very much interested in archeology. She’s active in the docents here at the Princeton Art Museum.
Let’s talk about Yale then, the people there, conditions for research.
Yes. I was teaching physics. One of the most rewarding classes that I taught was a class of selected freshmen, underclassmen, taking elementary physics—people who were particularly bright, or had enough science so they could qualify for the advanced course. I sort of invented a course of my own, in which we tried to derive much of the physics without using any calculus. I remember devising a scheme for proving, without using any calculus, that the orbits of two bodies moving around each other were conic sections. It was a tour de force. It’s almost easier to teach people the calculus than it is to go through the particular proof (as Newton did). But the students enjoyed it very much. I just had a letter a few days ago from somebody I hadn't heard of for years who was one of my students in that class. He saw that I'd given the Sillian Lectures, and said that the course he'd taken with me was one of the most stimulating he'd ever had. He was sorry he couldn't come to Yale to hear my lectures. I was very pleased by his letter. They were good students, and that always makes a difference. It stimulates the instructor to more effort. I think I was able to communicate to them a little something of the excitement and beauty of physical science.
Did you find the students any different, now that you were teaching them not too many years after you were there as a student?
I don't think so terribly different. One of the advantages of a young faculty member is that I think they establish rapport with the students more easily than the older men do, and I was sufficiently close to them so that I think it was easier for me to communicate with them than it would be now.
You said you started out in physics.
Did you have intentions when you went to put in some astronomy or make contact with Frank Schlesinger who was there in astronomy?
I knew Schlesinger. I dropped in on him once. He asked me to collaborate with him in an encyclopedia of astronomy that he was going to write. We would be joint authors. I think I discussed it with Shapley. He advised me against it, on the grounds that I would end up doing most of the work and not getting much of the credit.
This was about the time that the Harvard people were making the set you have on your shelf—HARVARD BOOKS ON ASTRONOMY.
What Schlesinger had in mind was a much more technical book. This was not to be a popular book. It was to be a higher level, a series of monographs or something, I forget now. I considered his invitation a bit and then decided not to accept it.
I didn't see much of the astronomers. And I don't remember whether I taught a course in astrophysics then or not, I think not. I taught several courses in elementary physics. I taught a course in aerodynamic theory in 1941. (Q. What year?) That was my suggestion, because things were getting tense in Europe. This was my second year there, and I thought that I should do something that would perhaps train me to take part in the war effort if we got into the war. And so I volunteered to give a graduate course in aerodynamic theory, which was a good way to learn the subject, I stayed one jump ahead of the class, and found the subject very interesting.
Did they start any of the accelerated programs for the war?
Not while I was there. I left shortly after we got into the war. Pearl Harbor was in December and I was gone, if not by the middle of January of '42, certainly by the end of that month.
Before you left for war work had you started getting interested in the interstellar medium? What brought this interest about?
Well, I'm wondering if that's true. I wrote three papers on the dynamics of galaxies. I remember now, I became interested, during my two years at Yale, in the differences between spiral and elliptical galaxies. I had what I thought was a bright idea that the differences between the appearances of these stars might all result from the same common influence; that the elliptical galaxies had lost their interstellar matter because they weren't rotating. As I showed in one of my three papers from this period, the interstellar matter couldn't stay in equilibrium, but would collapse to the center and disappear. In spiral galaxies, that were rotating, the gas could find an equilibrium in the disc. And in that disc it condensed into clouds and formed new stars that W. Baade about that time called the Population I.
Again, I had an idea that I was trying to develop and work out and prove, except in this case the idea was more complicated, and it took me a lot more time. In fact, I never did quite finish up, 40 years later. But the ideas were very similar to those which Baade was then developing. The difference was that Baade had much more data. He really had detailed observations, which of course I didn't have, and so his ideas were much more specific that anything that I had. But in principle they were essentially the same; that there were these two types of populations, two types of stars. "Populations" was Baade's term. One was produced by condensation of interstellar clouds, the other more primordial in nature. The ones that were produced in interstellar clouds were characteristic of the spiral arms in rapidly rotating galaxies.
I wrote it all up as one paper, and sent it off to some people at Harvard. I forget whether it was Shapley or Menzel or whether I sent it to Russell. I went to Harvard and gave a colloquium on the topic. I also sent it to Bok. And I was advised that it was pretty speculative, and that it would be better to cut it up into smaller units and not make such broad claims. I regret now that I followed their advice, because I think what I should have done is to have submitted sort of a broader paper to the OBSERVATORY or NATURE or something, which is what people would do now, and then follow it up with the more detailed papers.
But as it was, the three detailed papers which I published at that time had very little in them about the differences between the observed types of stars in these two types of systems. I do have a draft of the original paper that shows what I had in mind. But that was never published.
That certainly should be preserved. A very interesting document. My immediate question would be now, do you think, if it weren't for the war, would you have continued along this line, and by '44, by the time Baade actually did his work, would you have had it in hand, the concept of populations?
It's quite possible. I don't know. Of course, I was getting off more on the physics, and my objective was to have a deductive series of papers, to start off with the theory and then finally lead up to the differences between the different types of stars, as a consequence of pure physical theory. And that, I now feel, was an almost impossible objective for a young man to pursue. So I might never have gotten there. But I would have continued in that field, I'm sure.
You did work on one study with Baade when he came here as a visitor, I guess in 1950?
You were trying to explain galaxies which are highly elliptical, if you can call them that, or spirals without gas? Was this along the same lines? Did he come here with the idea that you had developed these early interests?
No, I don't think so. We had a program of visiting professors. We invited a number of people in to talk to us for a while, for varying periods. Fred Hoyle was here for a while, and he and Martin Schwarschild collaborated in the first investigation of the in homogenous stars, the giant stars. I forget whether Baade was here very long, or whether he was here for a full term or a few weeks, or what, but he gave us a number of very stimulating lectures. And I remember sitting in one where he described the SO galaxies.
I've always been very interested in severe catastrophes in the heavens, and what it would be like if a White Dwarf star went through a Supergiant star, what would come out the other side? What would happen when two galaxies collided? And things of that sort.
And so when Baade described the observations that he was puzzled by, why, the idea came to me immediately during the colloquium: "of course, the way to explain it is just the collision of two galaxies".
I got together with Baade after the talk and described my ideas and suggested that we write a joint paper. He said that would be fine. So I wrote up the theory, and he contributed the discussion with the observations of the SO galaxies, and we sent it off.
He needed velocities, to be able to see if the random velocities within a cluster were such, that, given a collision cross section, you would get a certain number of collisions per unit time?
I got those velocities from him, and he wrote a number of sections in the paper, that described what the SO galaxies are, what the observations are, what they look like. Then I wrote all the theoretical discussions of what the collisions are like and what they do.
How did people react when you started talking about collisions?
Well, they were startled. They were more startled then than they would be now. Now, it's very hard to startle anybody with a theory in astrophysics.
Stephen Hawking manages to do it, with his explosions of black holes. It really set physics back on their ears, a fascinating development.
That's contemporary, of course, Stephen Hawking.
Yes. At that time, the idea of collisions of galaxies was quite an interesting concept to people.
Did you have people absolutely unable to accept it?
Well, nobody pays that much attention to what anybody else does. They may have been unable to accept it, but if so, they didn't tell me. There's not much obvious controversy over almost anything that I've ever written. I think some of the greatest controversy I've ever had was over some of my early papers on space research. People came up and shook their heads sadly and said they admired my courage, Jesse Greenstein once remarked, I've already told you, when I told him I'd gotten involved in the Orbiting Astronomical Observatory, he shook his head and said "Well, Lyman, you're young. You'll live to see it fail."
He had put up a rocket himself?
Yes. It had blown up. That's one of my favorite stories, I think I probably told you.
I don't think I have the complete story.
Well, it's nothing, you heard the punch line. He worked on his instrument for many months getting it all fixed and ready for launch in a rocket. As he was watching the rocket being launched, it went up about 50 feet and blew up! He decided to go into theory. (Laughter)
Was this with someone else?
That's quite possible, yes, but I've forgotten his collaborator Guide Münch, possibly, or it might have been Louis Henyey, who was interested in instruments, and the theory of instruments. The Greenstein-Henyey camera was a joint effort.
Henyey got off on quite different things in later years.
I want to finish up the Yale period. I think I asked you he you felt about your future research there, your developing interest interstellar medium. Before you realized that the war was something you inevitably be drawn into, how did you feel about working at Yale at the time? Did it look like your interests in astrophysics would be satisfied there?
I don't remember feeling very strongly that they would not be. I enjoyed the Yale experience very much. On the other hand, ever since I'd been at Princeton, I had always thought that maybe some day I would return to Princeton, preferably as director.
You had that in mind?
I'm not sure anyone else did, but it seemed to me a wonderful place to be, with the great tradition of Henry Norris Russell, whom I'd be flattered to be able to succeed.
Did you talk to Russell about that at all or anyone?
I don't think I talked to him when I was here, but I remember talking with one person, Henry Hemmendinger, whom you may have never heard of, who was a graduate student when I was here. And we were talking about the future of the Princeton Observatory, and he remarked at that time that I'd be a good director. That's a remark that a young man is likely to remember of course. I don't know where he is now.
I don't know the name. Well, I guess your future at Yale was pretty much decided by the war.
And you went in the first month of ’42. Now, your war research was broken down into two periods: first you were at Columbia, and then you did sonar work.
Not exactly. When I was at Yale, I got a phone call from somebody who said he was with Columbia University, Division of War Research, on Fulton St., and wouldn't I come for an interview. So I went to New York and went up to Columbia University and looked for Fulton St., and was informed that Fulton St. was down at the Battery. And I finally made my way down to the Battery. Indeed Columbia University, Division of War Research, this particular part of it, had offices down near the Battery. Not as far down as Wall St., but they had a couple of floors of an office building down town on Fulton St.
How did you arrive at this particular position?
I had a phone call from a man named Slichter. This wasn't Sumner Slichter, this was someone else. He was with Division 6 of the National Defense Research Committee. Columbia University had a contract with Division 6, which was engaged in undersea warfare. That was the whole purpose of this NDRC Division. The headquarters of Division 6 had one floor of an office building, and they had some staff groups on a different floor, one under Slichter, one under Bill Houston. Houston I think was in charge of an effort on homing torpedoes, and Slichter had charge of a number of things, but one of them was coordinating underwater sound research. Research was underway at various laboratories in the country, but the underwater sound research was mostly at San Diego, including the Scripps Oceanographic Institution at La Jolla, and the Woods Hole Oceanographic Institution.
Were you a civilian or had you been inducted?
No, I was a civilian throughout the war. I assisted in the coordination of the undersea warfare research. I traveled to Woods Hole and San Diego, and talked to the people there, and I would come back to New York and talk with the people in Division 6 and go down to the Navy and talk with the people there. My chief liaison in the Navy was Roger Revelle whom I got to know really very well, a close personal friend.
In the final two years of the war, we had a small group set up, of which I was head, called the Sonar Analysis Group, which continued the same thing.
That was 1944-46.
Something like that, yes. In the closing year of the war, the headquarters of the group, that was me, was moved to Washington, where I had a desk in the Bureau of Ships. But the rest of the group continued in the Empire State Building.
You had contact with Henry Morgenau during this period also?
Not so much. Not during the war.
I see. His name came up in the previous interview.
I knew Henry from Yale. He was a very stimulating person. I was talking with him recently at one of the Silliman lectures.
But you had no relation with him then?
Not in the war effort, no.
Did you do any directed research at that time on the different war problems?
Well, my work involved talking with people who were doing research and telling them what they were doing wrong and what they ought to be doing. I mean, it was scientific administration. And the closing years were devoted to writing one major book, called THE PHYSICS OF SOUND IN THE SEA which was published, and recently republished. You may have seen it. I'm not listed as general editor in the book, but that was essentially my function. I would go over what everybody was writing, and object to it, and I helped write some of it. I became rather intimately involved with theories of underwater sound transmission, reverberation, things of that sort. Pekeris was a member of our group, Leslie Foldy, who's back at Case a number of years, Henry Primikoff, who's now in the physics department at the University of Pennsylvania, Bob Shankland at Case. He was head of the Underwater Sound Reference Laboratory that calibrated sonar equipment. There were a number of supporting activities all centered at the New York office.
In your role as administrator, did you see the problems that had to be attacked and then delegate them? Or did you react to problems that were under way?
A little of both, because there were a lot of studies that had been under way for some time. Roger Revelle was very much interested, of course, in exactly what was going on, and he and I would collaborate in discussing what the next step should be in scientific research, and how it would react back on Navy operations. I would help Roger write instructions to submarine commanders, how they would make use of the temperature information that they got from the newfangled instrument, the bathythermograph, that was developed for their use. We set up a group at San Diego to write instruction manuals for submariners as to how to make use of all this equipment. Was it George Stewart who wrote STORM? I think so. Well, we got him to join the group.
A professional writer.
Yes. There was a chap named Bill Sheville who was an invertebrate paleontologist, and we got him to spend a lot of time going down in submarines with submariners and talking with them about what their real needs and interests were. He was a member of that group. It was a diverse crew.
Did you find that the effort was really well put when it got down to ship commanders?
Yes. Yes, I think the effort had some effect. Oh, it's of vital importance for a submarine commander to know if, for example, there's a layer of steep temperature gradient. It's possible for a submarine to balance on that layer with all its power turned off. Such a quiet balancing submarine is very difficult to detect, because the presence of the thermocline, as it's called, bends the sound rays down, so it's hard to get an echo from such a submarine. So it's a wonderful way to get security.
We also got out maps of what the ocean bottom was like in Japanese waters, whether it was acoustically quiet or acoustically noisy, whether it was reflecting or non-reflecting, scattering or non-scattering, because a layer with irregular rock on it would scatter the sonar pulse and make it very difficult to detect a submarine. These instructions I think were useful to submarine commanders. They got big maps with instructions how to use them.
Was this your first experience with what looks like real team research and you're directing the team?
Well, I wasn't formally directing. I had no formal authority whatsoever. The official lines ran from Dr. Tate, Chief of Division 6 of the National Defense Research Committee, to the various laboratories. And I was in a group, a staff group, employed to give advice to Dr. Tate. But in point of fact, I never gave very controversial advice. I'd go out and I'd try to convince the people on the spot what they should and shouldn't do. It got so I would go to the Bureau of Ships, write a letter to the Chief of Division 6, which Roger would then criticize severely. Roger is always a wonderful person but he was sometimes a little slow at getting things done, but then we would rewrite it together. Then he would take it up and get it signed by the Chief of the Bureau of Ships. Then I'd go back to New York and when the letter came, I would prepare a reply to it from the Chief of Division 6 who was Dr. Tate, and after that was all authorized, I'd go to the laboratories and talk to them and try to get them to do what was requested.
I had no formal power. But it was a nice position to be able to influence things. If I had good ideas I could sell them and talk people into them. So it was, I think, a reasonably influential position in a very small sector of the war effort.
At the Bureau of Ships, this was your one contact with the military?
That’s correct. Through Roger Revelle. He was in uniform. He was a commander or lieutenant commander or something by the end of the war. I don’t think he rose to be captain.
During this period, did you have any informed "pipe-dreaming" sessions with other scientists about organized research, now that you were experiencing it at first hand? Possible future of organized research?
Yes. Roger had broad vision in this area, and I discussed lots of subjects in this area, of that type, with him. He was very good at getting other people to go along with new ideas for how to organize things. I went with him to talk to President Sproul, who was then head of University of California, to get some cooperative arrangement whereby the university would make a number of professorial appointments in underwater sound, in return for which the Bureau of Ships would state as a matter of policy that they intended to support this unit at University of California on a continuing basis — the sort of arrangement which, at the lower levels everybody says "It's impossible", but when you get to the top, "Very interesting suggestion", and it went through. I think then it's been quite modified, but this was an attempt to get civilian direction of the civilian effort in the Scripps Oceanographic Institution directed to underwater sound research.
This was Gordon Sproul that you had contact with?
That's very interesting. The association of civilian research with military funding, such as ONR, NDRC, was really the first big infusion of government money in basic research. Did you see this coming? When did you do this with Revelle? Was this after the war?
It was I think right after, right at the end of the war. I'm not sure the war was even over yet. I don't remember.
This could have been one of the times you were at La Jolla?
Yes, I went out there every few months or so. I forget how long I continued to do that after the war was over.
Did you do any astronomy while you were out there? Or did you have any contacts?
Is it coincidence that there's Revelle College now at LaJolla?
Oh, it's not a coincidence, it’s a direct result. Roger really promoted that southern campus of the University of California, and I think there was some possibility that he might be appointed the first chancellor of UCSD.
What happened to that?
I think some of the regents were opposed to his appointment for various reasons. I don't know exactly what. Roger's told me at some length but I forget the details now. Oh, I think his influence was instrumental. I remember him taking me out at one point and showing me where this building was going to go, as we were standing on a cliff overlooking the sea north of La Jolla, and telling these dreams about a graduate college and what it would achieve.
Did he ever ask you to participate?
No. Well, he may have explored that with me, I don’t know. I wasn’t interested in leaving.
I had only one or two other questions about your war work. I'd like to have some feelings from you about your regard for the war at that time. You were not doing your scientific work. Was there any anxiety on your part for getting back to your own interests? I'd also like to know when you began hearing about the Manhattan Project and the bomb.
I don't think I heard anything about the Manhattan Project or the bomb, until it hit the headlines.
You were not aware that anything was going on at Columbia with Fermi?
That wasn't my field at all. I was never involved in any nuclear physics activity, and the secret was pretty well kept. Carl Eckart once told me that he had gotten out of that program at about the last possible time when it was still possible. But this conversation with him was probably after the first bomb had been dropped.
You mentioned your contact with Carl Eckart last time. What was that contact?
Now, let's see, what was his official status? I think it was later that he became the director of Scripps Oceanographic Institution; during the time I was there, I think he was probably at the US Navy Electronics Laboratory. He was probably an associate director, something of the sort, in charge. He was one of the leading scientific figures of the US Navy Electronics Laboratory that did most of the underwater sound work, and that was located right in San Diego Harbor or at the entrance of San Diego Harbor. The University of California Division of War Research had a house not far away. They worked very closely together. I remember the civilian scientists would go to NEL to do their experiments.
The U.S. Navy Lab provided the ships. There were no civilian ships, at least not many. All the destroyers, and other things needed for lots of the experiments were Navy run, Navy operated, and were administered out of the US Navy Electronics Laboratory.
You worked primarily with the sonar group. Did you have any contact with the British work, not only in sonar but in de-gaussing ships to make them invisible to sea mines?
I was familiar with the de-gaussing effort, but not at all involved in it. That was not secret. That was not unknown to me the way the atom bomb was, but I wasn't involved in it at all. I just heard conversations. Some of the British sonar people actually visited us. I don't think I visited England during the war. I don't remember doing so.
That was the extent of your contact with anyone amongst the allies, just visitors coming through?
I believe so. Did I go through England during the war? I don't think so. I went there later, for the Matterhorn work, but not, I think, during the war.
OK. Well, how did you feel about the war?
Well, I was a member of the America First group, before we got into the war. I was strongly opposed to our taking an active role. But of course, when we were attacked, my opposition vanished, it was obviously too late. I felt that I personally was exceedingly fortunate to have fascinating, interesting and educational work to do during the war. I mean, it certainly was a fascinating experience for me.
Did you maintain enough contact with Russell to know his feelings about American entering the war?
No. I have a vague impression that he was more interventionist than I. Is that your impression? I think that's right. But I didn't see Russell that often. I didn't make much of a point of my political opinions with other people. I haven't been very active politically.
The “America First” idea was not political at that time, rather it was more of an emotional thing?
As the war was winding down in '46, you returned to Yale.
Right. During the war, I had an offer from University of Pittsburgh, at the associate professor level, and my wife and I went to Pittsburgh and talked to the authorities there. Then I went and talked to President Seymour at Yale, and he said he didn't think much of the Pittsburgh offer, but they nevertheless did make me an offer at Yale which I very much appreciated; an offer to set up an astrophysics unit which would bridge the physics and astronomy departments. I would have a foot in each department, offices both in the observatory and in the physics department, and my salary would be charged equally to both. Also, I could recommend somebody to fill an additional slot in the astrophysics unit, and I nominated Rupert Wildt, whom I'd come to know quite well. He was one of the people in the Sonar Analysis Group. I'd come to know him quite well and had a very high respect for him. He did, of course, some outstanding work in astronomy, though I must admit, mostly before he came to Yale.
Had you asked Schwarzschild to fill that position? I think we talked about this.
Yes. I asked Schwarzschild first. He was my first choice of course.
He was at Columbia by that time. I believe.
Yes. That's correct. I think he went to Columbia before the war, then went out, but maybe that's wrong, maybe he didn't get to Columbia until later. But in any case, he was at Columbia after the war, and I think he felt that the administrative arrangements at Yale were too uncertain. He didn't like the arrangement, felt it was a little uncertain. He thought it had perils. He didn't come.
Let me ask you one more war-related question. This is based upon P. Demarque's introduction for your second Silliman lecture, where he gave this very interesting recollection of your seeing a plane falling in flames outside the Empire State Building. Could you give the background of that story?
Yes. This was at a time when I was stationed in the Bureau of Ships, and the rest of the group refused to move to Washington, and it didn't much matter, so they stayed in New York. So, I commuted to New York upon occasion. On this occasion, I was there on a Saturday morning, and for that reason many of the offices were empty. Our office was supposed to be fully staffed. There was a cloud layer at about 800 feet, and an Army bomber came below there to see where it was because it didn't know, and found the Empire State Building right in front of it, and so it went into a steep climb, but hit our building ten floors, maybe 12 floors, above us.
We were on the 64th floor and it went in the 76th, 77th floor. The plane didn't fall down. There were bits of debris that fell down but the main part of the plane sort of went to pieces on those two floors. There were two engines. One of the engines went all the way through the building, fell out, and fell on a building on the other side of 33rd Street and set that on fire. Another engine fell down the elevator shaft and set a fire in the basement of our building. One of the elevators in our bank fell with the operator in it. The cable was severed somehow by all this, and it fell 64 floors, but the pressure that it built up held it at a steady speed which was not very high, and the girl who was the elevator operator broke a number of things, but she lived to tell the tale, that she'd fallen. 64 floors in an elevator. I've never seen so many fire engines as assembled around that building. We finally got out.
Did you get out by elevator?
We had to walk down quite a few floors. Smoke coming out and all that stuff.
Your impression, as Or. Demarque recounted it, was rather blase. You just looked out the window and said "Interesting".
That is a complete fabrication. My office was on the side facing the plane, and I heard the zoom of the plane, but I didn't hear the crash because the window was closed but the zoom stopped right above. I wanted to open the window and look out, and Peter Bergmann, who was a member of our group, said that was a mistake and sort of held me back. He was, of course, perfectly right, because things were falling down. Some of our office girls heard the noise and thought our building was being bombed, and skinned their legs diving beneath their desks. It's really history more of New York than of science, but it was quite an episode.
OK, well, we do have the complete discussion of your return to Yale, how you moved to Princeton, then of much of your early work there. So I think what we could take up now then would be your research in the fifties and sixties, unless I'm forgetting something.
You did so many different things. We also talked parenthetically about the beginning of your space research interests, and the reaction of the astronomical community to it. We didn't get beyond about the mid-fifties with that discussion. So I think we should talk about the development of your general research interests postwar, centered on the interstellar medium, stellar populations, evolution of galaxies, interstellar polarization, topics such as that—how you arrived at doing these various research interests. Then do your continuing work in space interests, because we've already done a certain degree on stellerator and Joan Bromberg had done a very good job on that, I would suspect.
OK. Well, after the war, I resumed my interest in interstellar problems, and one of the first things I became involved in, first at Yale, then later at Princeton, was the physical conditions in interstellar space. It became clear that to really have some idea of how material formed stars, for example, which is one of the general reasons for being interested in this topic, one has to know more than we did know then about the physical conditions in the interstellar gas.
Two problems that I considered were, the temperature and the electrical conductivity. My approach on both of these was just go through and compute them, using no great startling new physical ideas, but just to try to figure out what was happening. In the discussion of the temperature, after trying to think of all the different processes that heat up the gas and cool it, and finding the equilibrium in which the two effects balanced, I found that the regions where the hydrogen was neutral were much colder than the regions where the hydrogen all was ionized, and this has considerable effect on the way we look at interstellar matter. This result has had some influence on interstellar matter research ever since. I can't claim that it's any very bright idea, just a result of orderly working out of known physical inferences.
It had a lot to do later on with your ability to discuss conditions under which collapsing clouds were affected by magnetic fields in the galaxy, and under what conditions they were not.
Yes, well, it's certainly true. The purpose of the research was to tell us something about the physical conditions, so we could explore what happens in the intersstellar gas, and it has given us exactly that information that we needed, not all of it, but some of it.
I'm interested in how, to use a crass phrase, how "premeditated" some of your research is — in searching out ultimate questions, such as conditions for origins of stars.
Well, it was very much premeditated, in the sense that I felt that the first step toward investigating the grand design that I'd had a little before, about how the interstellar gas was related to the difference between spiral and elliptical galaxies, was to find out more about the physical conditions of the interstellar gas, as a preliminary for more detailed discussions of how the interstellar gas behaves under different conditions.
What's happened, as so often happens, is that the final goal has somewhat receded during my professional career. While we have a lot more definite information on how interstellar matter behaves, just how stars form still is not obvious. But the combination of theory and new observations has given us, we think, better insight into what the different routes may be, so it's still an active field.
In the early fifties, I see in many of your papers constant reference to Baade's observations and paper in 1944 on populations, and it seemed as though you were attacking the problem, to try to clean up all of the possible facets of the problem that would identify the two populations. You had first worked on the differences in composition of high and low velocity stars, then, a study of possible changes in velocities distribution of the stars due to relaxation, and then, early star formation, Population II. Is it correct to say then that you were following Baade's work at this point, working very hard to establish the population concept.
That's true, in a sense, although as I pointed out a little earlier, I sort of identified myself with that work because I felt that, to some extent, in a certain broad sense, the differences between recently formed stars and primeval stars had been something that I had come up with independently. So the reference was to Baade, because of course he'd done it in much more detail and backed it up with detailed observations. So I took a personal interest in trying to reinforce that picture.
Was Baade aware of your work?
I don't know.
You never discussed it with him?
I doubt if I really tried to emphasize it with him, because I didn't think any useful purpose would be served. I think I discussed it with Russell at one point. You're an historian so you have a professional interest in those things. Most astronomers are not.
You mean, in priorities?
Yes. As I've indicated, I wouldn't have any priority and my work was so specific—looking for the ideas without the detailed analysis. You can often find lots of people who had the ideas. The real credit should go to the people that worked the things out, as Baade did, as I did not. So I can't claim any enormous credit. But I can just present one reason why I was interested in verifying this whole idea. I identified myself with this research field because of my own early interest in that direction.
As you looked at the populations closer and closer, did the idea that they were two really distinct populations become firmer in your mind? Or did you start thinking that there was a gradual gradation of one population into the other? It deals with your developing concept of the way the galaxy evolves, of course.
Yes. Well, the concept of gradual gradations, I don't think emerged from my work at all. It became very evident in the proceedings of the Rome Symposium at the Pontifical Academy of Sciences. I think that must have been 1958. There were two symposia organized by the Pontifical Academy of Sciences, one on galactic nuclei, and one on stellar populaions, yes, in 1958. One of the chief conclusions of that conference was that there was a continuous range. But that was not my idea, and didn’t emerge from any of my work. That conclusion emerged from other observations, rather than from the theory of interstellar gas.
In ’51 you'd written a paper for the Washington Academy of Sciences on the growth of stars from interstellar clouds.
You certainly were getting very interested in pre-Main Sequence stellar evolution, and of course, at that time there was a very big problem as to where the Giants really were.
Yes. Martin Schwarzschild and I used to joke that I was interested in getting the initial stages of stars out of the clouds, but as soon as they began to resemble actual stars, I turned them over to him. That was his field. So I did not myself pursue any problems of pre-Main Sequence evolution, for example, let alone evolution along the Main Sequence. Those were entirely Martin's field of interest.
You were working on at that time, and were very excited about the Hiltner and Hall observations of polarization.
Yes, those were very exciting observations.
You referred to it in one of your papers as a "startling" discovery.
I made a mental note to myself to ask you: why was it startling? Something you really didn't expect?
Yes. Nobody had expected that there would be a magnetic field in space strong enough and uniform enough and regular enough to orient grains — that the grains would be aligned. If somebody had suggested this as a theoretical possibility, I don't think anybody would have paid any attention at all. It was discovered, as you know, in an attempt to check a theory of an entirely different sort proposed by Chadrasekhar,on the intrinsic polarization of light from early type stars during eclipses. Martin and I had a regular luncheon meeting with John Tukey and Johnnie Wheeler.
John Tukey is a mathematician, as you know, but he regards himself as a generalist and he's interested in all fields, and he probably comes the closest to being a scientific version of Leonardo da Vinci of anybody I know. Well, Leonardo of course did other things besides science, whereas John's aspirations I think are limited to science. But within science and mathematics he has very broad interests and very wide knowledge. I haven't seen him much in recent years, but during this period, he and Johnnie Wheeler and Martin and I would get together regularly for lunch to discuss new things in interstellar space. And it was at one of these luncheon discussions that he brought up the interstellar polarization problem, and he pointed out to me that an iron particle, if it were small enough, would form a single ferromagnetic domain all the time without any induced field. That provided one possible explanation for explaining the interstellar polarization. As it turned out, it didn't quite work, but it was close enough. A modification of it, including or combining our ferromagnetic particles with the Davis-Greenstein relaxation, it may be close to the correct solution.
Yes, that was the statement you made actually in your paper at the time. You have remarkable ability to draw together different theories and show how they would complement one another. Did you work very hard at doing this sort of thing?
Well, I don't remember that specifically.
You were very considerate of other people's views.
Well, I've always tried to avoid scientific controversies. I've never been a fighter, by profession — getting involved in a scientific fight in the literature has never appealed to me. The same thing is true in my professional relationships with colleagues here at Princeton and elsewhere. I go out of my way to keep things on a friendly basis.
You certainly understand this makes you no less of an interesting subject to us. (Laughter)
Well, I'm not sure that's true. A popular reaction is that a person is more interesting if he has had serious difficulties, arguments and fights with other people.
It's quite a serious question now. There are some people who say that controversy is a very common form of science. Other people would like to be very sure of that before they go on and make general statements like that.
Well, you can have controversy without being unfriendly. That is, I’ve had scientific discussions and disagreements with very good friends, but we each put these on a friendly basis. Also, neither side really espouses his point of view so very strongly, because we know that there are possibilities that both of us are wrong.
Your paper in 1953 with Schwarzschild, this in the second paper on the effect of interstellar clouds on stellar velocities, taking into account this time differential rotation of the galaxies, you found that the root mean square random velocity increased with advancing spectral type.
I was wondering, is this the first successful explanation of this observed effect that was really found just after the turn of the century? And never really fully explained except by different rotation?
Well. I think it was the first at the time, the first explanation that seemed to us to make any sense. Since that time a number of things have happened. One of our students here just gave me a paper the other day in which he re-explored this question. He puts more emphasis now on the random motions of giant molecular clouds than he does on galactic rotation. I've not tried to check his numbers, but he says that the rotational constants have changed since Martin and I wrote this paper, and that the galactic rotation, while it probably plays a part, is now secondary to the random velocities of the observed giant molecular clouds.
But you had that of course.
We had it, right. Of course we didn't have the giant molecular clouds. We had to speculate as to whether there were such large structures. Now they're observed in CO—carbon monoxide molecules. So the situation's changed. But it may change again.
OK. Again in that year in the OBSERVATORY you and Schwarzschild wrote a slightly more speculative paper on evolution of stars and chemical elements in the early phases of the galaxy, The OBSERVATORY, 73, 1953, P. 77. You equate the frequency of White Dwarfs, low metals of Pop. II, and the Stebbins-Whitford effect—quite an interesting study actually. You felt the Stebbins-Whitford effect was support for an evolutionary universe, which made sense at that time.- But you were able to show or discuss the fact the integrated color of a galaxy changed with time—this you thought was the interpretation there.
I wasn't too sure what your thinking was about the earlier galaxies. Did you feel that looking at a galaxy in its earlier phases made it redder than it is today?
Well, mainly that by looking at a galaxy in its earlier phase, there is more intense star formation activity — more supernovae, more white dwarfs being formed, more helium being formed, and that the galaxies (I forget the details) must have been bluer than our present galaxies would have been. You have to add that, in the sense that they had more early-type stars. The Stebbins-Whitford effect has long since evaporated. There are other changes that are thought perhaps to be present, but they're not as striking. The Stebbins-Whitford effect was really almost too large to be consistent with any physical explanation, we now think.
Right, but my confusion was that I thought Stebbins-Whitford effect showed that more distant galaxies were redder than they should have been.
What I would have done is take the theory that I just advanced, and work out from the theory what the observations must have been, because that's the chief advantage of a theory. It helps you to notice facts: Without a theory, I can't remember facts.
As I recall, the Stebbins-Whitford effect was later explained by DeVaucouleurs partly, and then by Whitford, as a systematic error in the calibrations.
Maybe what was happening is that we had some characteristics of the spectra of particular supernovae that would have explained that effect when they were suitably shifted.
But at least the rate of star formation was faster.
That was the theory. And that's still more or less believed. It's still sort of the accepted "party line.."
The interest though is that about the time you were writing that paper was when that basic idea began to be developed. I don't know if he was working on it yet, but Salpeter there was working on star formation in the mid-fifties, and I'm wondering if you had any contact with the people at Cornell during these years?
I suppose so. I've known Salpeter for years on and off, and we've always enjoyed getting together and talking about current developments and trading ideas back and forth without paying much attention about whose ideas are which.
When did you first hear of the triple alpha process?
I don't remember.
Continuing on into the fifties, I want to ask you a few directed questions on your paper with Baade. First, was this your first major excursion in your mind into studies of external galaxies? It certainly wasn't from what you've said now.
The first major one. I had published that short note in THE OBSERVATORY on dispersion of inbular magnitudes—the Hubble-Tolman analysis. That was years ago. That was on external galaxies but it was not a physical analysis of what was happening in galaxies, so I guess the paper with Baade was probably the first. In fact, I haven't done that much on galaxies as such. There was a paper on the dynamics of the interstellar medium Paper 3, on the equilibrium of gas within galaxies, so that had something to do with galaxies. But there hasn't been that much. In the paper with Schwarzschild on the evolution of stars and chemical elements we were just thinking about it.
Right. You did later get more and more interested in the evolution of the nuclei of galaxies.
Yes, that's right.
Let me ask you at this point, you were here at Princeton of course as you are. Did you have continued contact with Russell? Did you talk with him about any work on galaxies? Russell never worked directly on galaxies.
I guess that's right, I don't remember.
He was a stellar astronomer.
I don't remember any such. By the time Martin and I came here he was getting a little along in years. He came around every so often and discussed a number of things. He was very much interested in Baade's general point of view.
Did he talk to you about Baade then?
He published a paper on the maximum magnitude of stars in Baade’s, in Population II systems, I think. It was a short paper that rose out of a visit he’d made to Pasadena, I think. I forget now just what the point was.
That’s OK; we’ll retrieve that. Let’s move on through the fifties. You speculated on the existence of a possible interstellar galactic corona.
You said that radio noise had already suggested its existence at that time.
Yes. That evidence subsequently was withdrawn or dropped. At that time, people thought that they could see radio noise coming from an extended corona of our galaxy, an extended galactic radio halo, and that they could also see it around other galaxies. Since that time, the observations in our own galaxy have been revised. The radio emission is so irregular, because there's the North Polar Spur and various other features. It's very difficult to represent it as a displaced spheroid, which is what they were doing — a spheroid centered at the galactic center. One can say the observations can be represented in part by such an aggregation, in part by a lot of irregularities, but you can also just blame it on the irregularities and let it go at that. Measures of our own galaxy really don't point unambiguously to any radio halo.
It may be there, but it doesn't stand out clearly above the irregularities. And the same is true of most other galaxies. Now, from time to time, talking with radio astronomers, I hear that they've found some galaxy where they think there is a clear radio halo. And I suppose there may exist. But the trouble is, you can look in almost any direction and you will see radio emission from something or other. To distinguish what's due to some very distant cluster of galaxies, and what's due to a local galaxy, is not always easy. So, with other galaxies also, it's not clear. It's not a clearcut case. I think the main evidence for the galactic corona, referred to in my paper, is the existence of low temperature clouds at large distance from the galactic plane.
You seemed to be interested in the possible hot component because you had stated in the abstract of the paper that it should be partly optically visible. Some absorption should be visible only at wavelengths shorter than 2000 Angstroms.
That's right. As I said, the evidence for the corona was the existence of cold neutral clouds; to understand how such cold neutral clouds can exist, you need a hot intercloud medium whose pressure can keep the cold gas from expanding.
One of the purposes of the Copernicus Satellite was to detect such a corona, and we have in fact seen it. Ed Jenkins has written several long papers on the topic. There was some controversy whether it might all be produced by regions of ionized gas surrounding the stars we looked at. But Ed's analysis seems to show that that was probably not the correct explanation.
But still I couldn't help but bring it lip because, certainly at this time, in the fifties, you were talking very seriously about space. You had been for a number of years.
I'm sure you put that explicit statement in there for a good reason.
Yes. I hoped that some day, we'd get a satellite in space that could make observations. You can see that about the same time I published a paper on astrophysical research with an artificial satellite that dealt with the same topic.
That's right. This model of the existence of the galactic corona seemed to be a necessary condition for Fermi's and Chandrasekhar's model for spiral arms, or how one could sustain the spiral arms?
Were you involved in that?
No. Well, I'd been interested in that, on and off, but I certainly had no share in that original paper.
It wasn’t the justification for your interest in writing this paper?
No, I don’t think so. You need some ionizing gas permeating the galaxy, but it needn’t be so hot, as far as the Chandrasekhar-Fermi paper would have it.
Have they since found sufficient material to stabilize the spiral arms, or do they have a completely different theory of how spiral arms remain?
Spiral arms are quite an interesting problem. One of the best theories at the moment attributes them to density waves, and the density waves in the distribution of stars affect the interstellar gas in a much more dramatic way than they do the stars. The gas tends to develop shock waves and much larger density concentrations than you'd get from stars. Where the gas is compressed by shock waves, you get star formations. It is interesting and may be true. There are complications that it's hard for that theory to explain.
Could you say it’s one of the best around?
It has the advantage in it seems to explain simple two arm spirals. Maybe not in our own galaxy though, where things are more complicated.
Your continued interest in star formation, 1956 and on, led you to the paper "Star formation in magnetic dust clouds": with L. Mestel. That was in the MONTHLY NOTICES, 116, 1956.
You were trying to get clouds to collapse, I guess. You needed an obscuring condition, and you were dealing with magnetic fields here.
How did you come to work with Mestel?
Mestel was a postdoctoral fellow, for a period between six months and a year. We've had a number of people here in that capacity, both from abroad and from this country. One of our first postdoctoral fellows was Alan Sandage in the early fifties. And E. Shatzmann was here too and among postdoctoral fellows and visiting professors, we've had quite a few leading astronomers at Princeton.
Was this a policy that you instituted?
You found it stimulating?
Yes. We've cut down a bit on our visiting fellows recently, because the Institute for Advanced Study has such an active program in this field, but we still have a few.
OK. What was the origin of that particular paper? Was that from your direction or Mestel's?
No, that was from Mestel's direction, Mestel's interest entirely. I got my name tacked onto it because of a suggestion I made when we were sitting in one of these little offices at the observatory. He was presenting the problem of how you got the cloud to collapse when the magnetic field was so strong. It suddenly occurred to me that the neutral component could move through the ionized components. So I pointed this out to him, and we worked out a few of the details together. It turned out to be promising, so he incorporated that into his paper, and then agreed to put my name on the paper, since I had made that particular contribution. I was happy to go along with that. But he essentially did it all.
In the paper you acknowledge contact by letter with Cowling and discussions with him. I guess he had a similar theory that ran along parallel lines?
I forget now. That was probably with Mestel, I don't remember. I could look in my files. I probably have the letter if we did correspond.
Well, the reason I'm interested, we followed Cowling's career too and found him very interesting. Also he wrote voluminous and wonderful letters.
Yes. He was here as visiting professor for a number of months.
How did you go about choosing the people that were to be visitors?
Martin and I would get together and decide who was interesting and stimulating that we'd like to have here, and ran through the list of astronomers that we admired.
Did it depend at any point on what research interests you and he had?
To some extent. Well, we asked ourselves the question: who would we like to listen to? What subjects would we like to hear described? We asked him to come and give lectures. We of course went to his lectures.
Considering the fifties, we've covered I think your noninstitutional research interests now. We've already talked about the Stellarator. We can keep that in reserve. Your interest in space astronomy I want to pick up a little later. What about the growth of the institution? Did you have a direct plan in mind for how the Princeton astronomy department was to grow? Did you try to develop certain large studies such as the space project or physics projects? The Plasma Physics Lab was separate at the department at every stage?
Yes, they had no relationship to the department, entirely separate. I think the organizing committee had members of various departments on it, but it did not report to the department.
How did you divide your time between the Plasma Physics Group, when you were running it pretty much, and the astronomy department?
50-50. For a number of years, half my salary was paid indirectly by the Atomic Energy Commission, which reimbursed Princeton University for this cost.
Did you feel that it might have kept the department here from growing?
Well, I did the best I could to continue development.
Was there much growth?
Well, actually space astronomy developed and our Copernicus project was well under way before I resigned from the Plasma Physics Laboratory. I resigned from the Plasma Physics Laboratory in 1966, and Copernicus Satellite was launched in '72. It must have been started in 1960, something like that. I was at the Plasma Physics Laboratory 1951 to 1966, a total of 15 years.
During this time, it didn't stop you from developing the rocket group and continuing on with your personal research?
How did Princeton, the university, look at it? What were your relationships with the administration, as far as developing astronomy here goes? Did you feel the need? Were they asking you to develop in certain directions?
No. there was never any request that I develop in certain directions. That initiative was entirely up to the department, and especially to me. The only time that we asked for additional support from the administration was when we asked for professorships for two associates, Jack Rogers and Bob Danielson. This was in the expansionist days, and we assured them that those positions would be supported in part by contract research, which was true, and there was no real opposition. We talked to the president and the positions were approved.
What about the beginnings?
In the beginning, it was entirely supported by contract research. There were no negotiations with the administration needed.
Even in the fifties?
Well, there was a committee on sponsored research, that we had to get approval from for things. We did have trouble with that on Project Matterhorn when we wanted to get into experimentation.
You had trouble from them?
Yes. I think I've covered that in my talk with Joan Bromberg. They didn't like the idea of our getting into experimental work. Oppenheimer at the Institute also had the same negative approach, and it took us quite a little effort to get first local approval, then AEC approval, for the experimental work.
Was there any reaction from the administration's direction when you wanted to set up a rocket group, which you had for many years wanted to set up one way or another? It probably started back at Yale.
Well, actually, yes. Leo Goldberg was made an offer by Yale to come and set up essentially a rocket effort for space astronomy. But with us here, the rocket group didn't get established till after the Copernicus program, after the Orbiting Astronomical Observatory program had been started. Then the rocket group was set up to give us practice in the sort of things we were going to do with the satellite. So it was sort of a reversal of the usual order. The problem is it's difficult with small rockets to do so terribly much with stellar spectre. It can be done, and Don Morton did it, first with gyros, then finally with the guidance systems that had meanwhile been developed by NASA. But actually I think it was partly a result of a NASA suggestion, that we might be better off if we did some small scale work with rockets while we were getting involved in the big satellite.
I'm trying to create a chronology of your work supporting rocket research, then also satellite research. In '56 as you already mentioned you started writing some papers on research for the artificial satellite, the scientific uses of earth satellites. In '59, interstellar research with a satellite, that was in the PASP—
Then there's an unpublished report from 1946. "Astronomical Advantages of an Extraterrestial Observatory", Project RAND.
Oh, Project RAND, that's right. So you had a really longstanding detailed interest.
How did the Princeton administration react to it? Were they willing to support you to the hilt?
Well, the question is, what does it mean by "support"? When I came here, I had support in the sense of fluid funds, that could be used for visiting professors and postdoctoral fellows and all those things. And as long as I lived within that framework and got support from the outside, there was no need to request additional support. So the question never really arose, until we approached the university for these two additional faculty positions.
I see. In other words, there was always enough to work within the limitations you set, on doing space research?
Yes. We got funds from the government. External funds.
Princeton never minded that this kind of research was going on.
No. I think there was general enthusiasm for it. Everybody thought it was interesting, perhaps even spectacular, and wished us luck. Martin's Stratoscope was popular. We were asked to give talks to alumni, and there was a general air of encouragement and moral support, but we didn't ask for anything else.
When did you feel that you were "home", as far as the astronomical community was concerned, with an established program that was going to culminate in something as effective as the Copernicus satellite or the LST that you always had in mind?
Well, of course, concerning the LST, whether we'll have anything to do with that is still not quite clear. But the Copernicus satellite started gradually. We were under pressure from the Air Force first to get started on that. The Air Force came around to us and said, "Won't you please make a proposal for doing something on a satellite? If you don't do it we're going to get somebody else to, and we'd rather have you".
So our original plan, I think I may have told you this before, was, when Stratoscope finished, to shift those personnel from the Gallom telescope work to the satellite work. But the Stratoscope work was somewhat delayed. The launching of the Soviet Sputnik made it desirable for the Air Force to start work on a satellite. So we agreed to submit a proposal to the Air Force, actually through the Cambridge Research Center, for supporting studies and various small efforts.
Who was it that approached you?
A chap named Miczaicka. He's an astronomer who went to work for the Air Force Cambridge Research Center, at Bedford Field or something like that, I forget now. I had known him. We had known each other before. He approached us and asked if we wouldn't like to submit a proposal. And we started on it, I discussed it with Martin, and we finally decided to do so.
Did the Stratoscope staff eventually transfer over, or did you hire new staff?
Well, we asked Jack Rogerson to come back. He'd been one of our graduate students and he was working originally on Stratoscope. We took him away from Stratoscope entirely into the Orbiting Astronomical Observatory, and all the rest of the staff we hired were essentially new.
Bob Danielson would have been transferred to the Space Telescope or something, if he'd lived, after the end of the Stratoscope work. But he died, about a couple of years ago, after the Stratoscope had ended but before we had a chance to get involved in the Space Telescope.
What are your general feelings about the entire Copernicus program? It would take up a tremendous amount of time, I think, to go through it piece by piece.
Well, I've been very pleased, the way that's worked out. We've been extraordinarily fortunate that it's done as well as it has. I think one of the most exciting periods I've ever had in my life was being down at the Goddard Space Flight Center, when they first turned our equipment on, several days after the launch; seeing if it was going to work or if it was not. That was a "moment of truth". August of '72.
One could see in the first 30 seconds that our equipment was operating more or less properly. And during the first month, the general outlines of its operation became clear. There were certain problems that we hadn't anticipated, but on the whole it was functioning very well. It continued to function very well. It has the resolution we'd hoped for and the photometric accuracy that we'd hoped for, and it's given the results that we'd hoped for, so we're really pleased.
During the long development process of the OAO and Copernicus, were there any serious setbacks?
Oh, endless setbacks. Financial setbacks. NASA would run out of money and tell us to stop work for a year, pretty much, on what we were doing. Then there were development problems that came up, things we hadn't thought of that suddenly came to mind. We had the electronics all built, and then they discovered that transistors, then a relatively newfangled invention, degraded with time. All our equipment was so old, it wouldn't last in orbit, so we had to rebuild the whole thing from scratch with new and improved transistors and with more margins of safety to resolve the effects of degradation. There were endless other difficulties. We'd go into tests and half of the photo tubes would blow out and the other half wouldn't work. We had to find out what was wrong, go into the details, have conferences, get them fixed up. There were problems of scattered light. I went down to Goddard and actually made tests myself with equipment — moving light bulbs back and forth while somebody else read the meters. Then we had a bomb scare. We had to leave the clean room and go out into the parking lot in our white coats. Yes.
During what period? This was in the late sixties?
Yes. Even recently they have had bomb scares. Occasionally somebody phones up and says "I've planted a bomb". So they make everybody leave, and of course they never find a bomb, but who knows? There were of course many difficulties, with large and complex apparatus of that sort, there's bound to be.
With the time limitation, the important question to ask now is: is all of this documented? Do you have the materials, minutes, notes, letters, various contracts as they came in, sitting in boxes?
I can show you what I have. I have my own minutes of our regular meetings, which outline all the activities. There are special little folders on all the problems of tube failures, leaks that developed in the bellows, computations that we then made to see the effects of the leaks.
This is what we would want to be sure exists. Then we don't have to spend a lot of time dealing with it right now.
Certainly Copernicus, and your being approached, had a lot to do with your longstanding involvement. You were involved in the Astronomy Missions Board. At the time Copernicus was developing, you were also asked, or you might have initiated, I want to get this story straight, to consider a large space telescope. Now, at first was Copernicus considered to be the large space telescope?
No, Copernicus was never dignified by that name. The so-called Large Space Telescope, (LST), you've probably seen that little paper I wrote on the history of the space telescope, that came out in some symposium on that subject, it's in my bibliography.
I have it. "Large Space Telescope, a New Tool for Science". Your paper was "History of the Large Space Telescope", 1974, AIAA 12th Aerospace Sciences Meeting, Sheridan Park.
I guess it's document CP 101.
Whatever that means.
I don't have a copy of this, definitely do not. I have a number of questions involving the LST that we can maybe get at the history of it.
I'd be interested in the early paper you had in '68, "Astronomical Research with the Large Space Telescope".
At that time, you were talking about 120-inch aperture, and you were referring to it as the LST. Was this the first reference to it? Did you coin "LST"?
No, this was the culmination of a half dozen years of develop-ment. The Large Space Telescope was first discussed at a meeting, a summer study meeting in Iowa, 1962, when the OAO program had started but only just started. Then there was another meeting in 1965. That's the Wood's Hole Meeting. As a result of that meeting, they then recommended that a space telescope with 120-inch diameter roughly, designed for many astronomical uses, be studied further. Then the Ad Hoc Committee was set up shortly after that, and that had an active life. I was chairman of that. And this paper was then the result of the deliberations of that committee, attended by many scientists, to discuss what the scientific program should be.
Have you maintained the minutes of these meetings too in your correspondence?
I suppose so. I hope so.
Partly this is to identify, in your mind too, what is important. As far as the telescope itself goes, considering design, size and the sources of funding for it, did you ever approach or consider approaching private sources?
Do you have any rationale for that?
It was such an enormous project, several hundred million dollars, at least. My suggestion was that we approach the United Arab Republic for a joint proposal. But I couldn't sell this to my colleagues or to NASA.
What did they say when you said that? When was this?
Everybody laughed. I thought it was an excellent suggestion. I think it would have been fine. The more undeveloped a country, sometimes, the more they like to become involved in the early pioneering scientific ventures. It seems to me it would have been a wonderful public relations angle for Iran or the UAR.
You made these suggestions in the sixties?
No, I made it in the Space Telescope Working Group, of which Bob Odell was chairman, when we were having trouble with Congress. Congressional approval was obtained last year in '77. I must have made this suggestion in '76, '75, quite recently.
The history of the LST, now the Space Telescope I guess it is, certainly is a varied one. It's been on and off and on again. There have been many different ideas that you have brought out, for actually how it would be implemented. One of the first questions you brought up, as to the nature of it, was, where it would be? Whether it would be in free space or on the moon? Were there two serious schools of thought about this at the time?
Yes, there were two schools of thought. I never took very seriously myself the location on the moon, but there were one or two members of that committee who did.
Who were they?
Bill Tifft was the name that I mainly think of in connection with the location on the moon. And there may have been others also. Astronauts like the thought of something on the moon that would be operated by astronauts, but Tifft is the only astronomer I remember at the moment that I can identify with this. The argument was that there may be a great lunar base established by NASA; if it does, we ought to be in a position to go along with it. I felt that the cost of anything on the moon would be so much greater than the cost in orbit that it was very difficult to justify. Furthermore, you lose some of the advantages of space by being on the moon. Particularly the gravitational flexure distorts the mirror, so I've never been a supporter of a lunar location. In fact that was shortly afterward dropped.
I wanted to query you on that because in your earlier articles you had mentioned both as possibilities.
Yes. That was why it was called a space telescope rather than an orbital telescope, for one thing.
I see. You indicated that you're not sure of what your association is with the project now. And I do know that Princeton did not get the NASA grants for, what part of it?
The Wide Field Camera.
The wide field camera. How do you feel about that? What's been happening?
Well, I was very sorry that we didn't get that, but I think it's readily explained. I'd known for many years that for the space telescope to be possible required television sensors. I felt that taking photographic film, to develop it and scan it out in orbit, really was not very practical. One can visualize it but I think it would be impractical. So with NASA support, we started a small program to use television, as an astronomical sensor, a long time ago, I forget just when — l0, 15 years, I don't remember now. And shortly afterward we concentrated on the SEC television tube and we've, had a program that's been growing in intensity, and by the time we submitted our proposal, we had what we felt was a workable SEC tube. That type of approach to television has certain disadvantages. Some of the people in NASA felt that one of the main disadvantages was that it wasn't the wave of the future. It wouldn't be developed any more by the companies involved. They were much more interested in using a solid state device, the CCD. JPL was developing the CCD for planetary research. Some people on our staff felt that we should have proposed the CCD. That was not really possible. We'd spent a lot of money on the SEC. The CCD didn't really exist in the size needed. In retrospect I think we had no alternative but to submit a proposal based on the SEC, because of all the effort that had gone into it, and it was not clear that the CCD was really far enough along to be used. But when it finally came down to the actual evaluation stage, looking at where the CCD was at the moment of evaluation, the evaluation committee felt they really ought to go to the newer, simpler, and somewhat more powerful device. And that's what they did.
That leaves you somewhere out in the cold.
Yes. We'd assembled this big space effort, and whether we can keep it going isn't clear. After Copernicus stops.
Does this mean possible staff cutbacks?
Yes. It could. Well, of course, I will be retiring, and Martin retires in another year, so it's no disaster, if that effort terminates here, and other people do other things. But on the other hand, Princeton would like to remain active here in astronomical research, and may do so. We have other ideas that we're trying to promote.
What about the other changes in the nature of the LST? The reduction in the size of it. I don't know if there are any changes in the guidance systems or not, but there have been a number of people bidding on those.
Yes. Well, the change in the size of course was partly a result of Congressional pressure to save money, but it had a good deal of scientific and engineering support, because at the smaller size, the optical houses felt they had reasonable confidence they could build it and operate it and it would work. At the l20-inch or 3-meter level, there was some uncertainty. It's not a big difference, but it's enough so that it was beyond their experience, and it was a little risky.
Was there any question of fitting it inside a space shuttle?
I think the 3-meter might have fitted in, though actually I don't know. I had the impression that the 3-meter was chosen to be the biggest size that would fit into the Space Shuttle, but when it came down to the nuts and bolts maybe it would have been a little bit too big. In any case we were quite happy with the 2.4 meter.
Today, there are some astronomers who prefer ground-based research. Others feel very strongly in favor of space research. It seems reminiscent, since there's only a finite amount of funds and they're always dwindling, of the early days of the formation of AURA, when there was a rift between the radio people in the formation of NRAO and interests of optical astronomers, and the future of a national observatory in the Southwest. There was a big meeting on this in 1956 at NSF. You were invited to that meeting. I don't know if you recall this?
I don't. I believe I didn't go;
I'd like to bring you up to the present and ask you about the space program, the VLA, the major projects now that are under funding. Do you feel they are causing rifts of interest in astronomy that may be injurious in the future?
I don't think so. There is always disagreement of course between different people. Each person feels his own project ought to be more fully funded. But in the past at any rate, astronomers have developed the concept of a balanced program, in which optical space astronomy, ground based astronomy, infra-red, X-ray, radio astronomy, all move forward together at the maximum pace that the total funding will permit. And I think that's been successful. Different branches of astronomy have gone forward, and you really need research and results in all of these fields, to explore the universe in the most effective way. And I hope that we can maintain that harmony in the future, because once we start squabbling over which discipline in astronomy is more important, we'll end up by not getting much of anything, probably. At any rate we would have a lot of very unpleasant fights.
This certainly is your attitude and your philosophy. Would you say the general community agrees with you?
I think so. The Greenstein Report, for example developed the same philosophy. I was a member of that, and followed it with great interest. The Astronomy Missions Board was of course entirely restricted to space astronomy, but there again, they've tried to develop a balanced program within the framework of space research, and I think they were reasonably successful. The Space Sciences Board, too. Within each general subject, the pressures for developing some sort of a compromise overall proposal are so strong. It's so obvious that the welfare of the subject will be promoted, if the leading people can all agree as to what the next step should be. The physicists also, I think, have tended to move in this direction. Not always. There are sometimes open fights.
Have there been some open fights that are serious enough to at least mention here, in astronomy?
I don't know of any in astronomy in recent years. But you may know. No, I don't know.
Dr. Spitzer, you can ignore this question if you wish. I have recently heard that some controversy exists as to what is the best instrumentation to fly on the shuttle. You have been noted as saying that wide field surveys are best done from the ground, saving space on the shuttle for deeper probes. Could you comment on this? (Insert dated October, 1978) Dr.
I would prefer not to comment on this one. The question is a bit technical, and would require considerable discussion.
The question also is, looking for this parity between all branches of astronomy, so that it can move forward effectively, you're still working within a limited budget frame.
And that frame seems to be getting more and more limited.
Well, I don't know that it's getting more and more limited, but it certainly isn't getting any bigger either.
Yes. What do you see as the future fate of the health of the science? Can it stagnate?
Oh, I don't think we're stagnating at the present time. People who say we're stagnating get quite alarmist about the present rate of government support in astronomy, but if you just look at the rate at which papers are appearing in the ASTROPHYSICAL JOURNAL, and think what it was like even five years ago, this is fantastic growth.
It’s positive growth? Not just profusion of the same types of research or variations on major papers? I can’t evaluate it, I want your opinion.
Oh, I think it's real. It's true in any period that most of the papers that one sees are not world shaking. But it's real progress. I don't think any one discipline is going to get what it would like. That's always been true, and it's probably a good thing. But the important things, I think, will move forward.
We have not covered, unless you think we have, your general impressions of galactic research, your study of the origins of galactic nuclei, the nature of galaxies. I'd like your general comments now on the direction of the study of external galaxies as systems.
I've really not done much in that field. My work on external galaxies is more devoted to the general problem of what happens to a spherical stellar system, and the frame of reference of that work has been more directed towards globular clusters, which appeal to me because they're a simpler physical problem. We have much less observations of the center of a galaxy. It's apparently much more complicated. It's also, let's admit it, perhaps more interesting, because more things happen; but quite a lot of things happen to some globular clusters, too. X-rays come from globular clusters, and there may be black holes at the centers, so there's a lot of interest in those topics.
Do you have any particular feelings about the direction of study that is beginning to interpret the nuclei of galaxies as quasi-stellar objects or as supermassive black holes, linking all of these fabulously glamorous things together?
Yes. I think it's certainly exciting and it's going to be an active field of research. Princeton Observatory is concentrating more of its personnel on that field than it has in the past. We have two of our younger people now are experts in, and working on external galaxies.
Is Ostriker one of them?
J. Ostriker works in all fields of theoretical astrophysics. Rich Gott and Ed Turner are working primarily on external galaxies. Ed Turner is at the moment at Harvard, but he's accepted an appointment here. He's an observer of external galaxies.
Where are the most progressive elements in cosmology today? Looking more at galactic evolution? Looking more at mechanisms for understanding why there are different types of galaxies?
How do you mean, progressive?
Most likely to bear fruit.
Well, I would hesitate to pick on any one topic, but certainly some of the most exciting topics today refer to what goes on in the nuclei of galaxies. The origin of double radio sources, the jets that come out of galaxies, the quasars. That's the subject of a special conference organized in Rome at the Pontifical Academy of Sciences a few years back that I attended. There's been a lot of activity since then. A lot more is known. But it's still sort of a mystery.
But there are other topics in astrophysics that are also of interest. There are supernovae explosions, what happens to them, how the interstellar gas forms stars, how molecular clouds are maintained and what their fate is.
Talking generally still, do you feel that the young astronomers now, just out of graduate school and working on these types of problems, are attacking them as you would have attacked them at the beginning of your career? Or do you feel that there is any change in the discipline, subtle or otherwise, that has changed the way astronomy is done?
There's a lot more interest in physical processes now than there was when I entered the field. When I entered astronomy, most of the papers at astronomy meetings were on orbits and spectroscopic variables and various things. There weren't many physicists loose in the field. Now, it's almost more physics than it is what formerly used to be classical astronomy. So that's growth, in a sense, of the sort of thing that I've been interested in. I just happened to get into it at a time when it was taking off. But the objectives, of course, are still the same. The qualities of mind that are needed to penetrate the secrets of nature haven't changed that much.
Not in that short length of time anyway, I guess.
Let me ask you just a few straight structured simple questions. I think that will be it. You may choose not to answer these. Is the universe open or closed?
We don't know, of course. But my own betting at the moment would be that it's open. But I wouldn't bet very heavily on the reliability of that.
Is there any particular work that you feel points in that direction? Work of astronomers and others?
It's a combination of things. I think the paper by Gunn, Gott, Schram and Tinsley summarizes the evidence pretty well. The arguments that it's closed have also been summarized by Peebles informally at some of our meetings. He may have published something on it. I don't find them so convincing. But one must admit that the arguments that it's open are not really conclusive at all.
Do you feel that there may be sufficient mass to make most clusters of galaxies dynamically closed?
Oh yes. Most clusters of galaxies must be in a steady state. I don't think there can be too much question of that.
How much faith or lack of faith do you have in the radial abundance gradient in our galaxy, as it's being studied today?
Well, I must admit I myself have not looked at that critically, but one has the impression that so many people have been getting the same result now for so many years that I'd be inclined to believe it. Furthermore, it's not unreasonable physically. That is, the heavy elements are increasing towards the middle, which is where there's more activity, so it's theoretically plausible, and observationally seems to be generally confirmed.
It's a good model then?
I'm inclined to believe it.
We already started talking about the fact that the early postwar funding was militarily oriented. Then it switched over to non-military. Do you feel that non-military funding has been as effective, less effective or more effective than supporting pure research? Or is there any way to compare the two?
Well, I must say that the Office of Naval Research, which is a small part of the military funding, achieved quite early a very high effectiveness, in my opinion, in organizing the support of basic research. But I do not wish to fault what the NSF has done, because I think it's also very well organized. I'm all for the peer review system. Like any other system that involves human beings, it has its problems and occasional faults, but I can't think of a better system. I'm all for it.
I could ask you plenty of questions about the ApJ Editorial Board but we're running out of time.
I used to be active on that, but I'm not any more, so I couldn't answer them.
I was thinking of the period when you were active.
Oh, I see.
You did agree with the editorial policies?
Yes, and I was active on the committee that tried to get the American Astronomical Society into closer touch with the ApJ. In fact, there's been a gradual change in the control of the ApJ, you know, from the University of Chicago to the Society. I don't know whether that is of that much interest.
Did you have any connection with Jason?
No. Some of my friends did, but I have not.
That, very quickly, unfortunately, brings us up to the present, with all these general shotgun questions at the end.
My main claim to political fame is that I was on Mr. Nixon’s Second Enemies list. I was an early support of Mr. Eugene McCarthy. My wife and I contributed substantially to his campaign. At least, I assume that’s why. Other people here at Princeton who were on that list had also contributed to Gene McCarthy at a very early stage.
That’s the qualification of most people I know who got on the list.
It didn’t amount to much, but in the eyes of the students, it almost exonerates my more conservative attitude on some other problems.
Well, happily we can smile about it now. Thank you very much.
ApJ 90 (1939) pg. 675-688.
MN 100 (1940) pg. 396-413.
A.S. Eddington, "Diffuse Matter in Interstellar Space" (Bakerian Lecture), Proc. R.S.A, III, 424 (1926).
Given in spring, 1978.
ApJ 93 (1941) pg. 369-79; 94 (1941) pg. 232-244; 95 (1942) pg. 329-44.
ApJ 113 (1951) pg. 413-418.
From Interview #1.
ApJ 114 (1951) pg. 398 w/M. Schwarzschild and R. Wildt.
ApJ 114 (1951) pg. 385 w/M. Schwarzschild.
J. Wash. Acad. Sciences 41 ()ct. 1951) pg. 309.
ApJ 73 (1953) pg. 77-79.
Op. cit. (1951).
Obs. 61 (1938) pg. 104-106.
Earth Sat. and Research Vehicles pg. 69-78 (1956).
SCIENCE 161 (1968) pg. 225-229.
secondary electron conduction tube.
charge-coupled device tube.
very large array (VLA) radioscope.