V. A. Ambartsumian

THE EARLY CAREER OF VIKTOR AMAZASPOVICH AMBARTSUMIAN: AN INTERVIEW OVERVIEW

Viktor Amazaspovich Ambartsumian is the Soviet Union’s leading and best known theoretical astrophysicist. Born in 1908, Dr. Ambartsumian graduated from Leningrad State University (LGU) in 1928 and carried out his graduate study at Pulkovo Observatory. In 1934 he organized the Soviet Union’s first department of astrophysics at LGU. Elected a corresponding member of the USSR Academy of Sciences in 1939 (full academician in 1953); Dr. Ambartsumian returned to his native Armenia in 1943 and founded the Byurakan Observatory in 1946. He has been director of Byurakan Observatory since its founding and has been president of the Armenian Academy of Sciences since 1947. He was vice-president of the International Astronomical Union (IAU) from 1948 through 1955, and he was the IAU’s president from 1961 through 1964.

Dr. Ambartsumian’s scientific work has spanned many fields, in particular stellar physics, the physics of gaseous nebulae, statistical mechanics of stellar systems, extragalactic astronomy, and cosmogony. Dr. Ambartsumian was the first to study the transfer of stellar radiation in a gaseous nebula, and he worked out the fundamental theory of ionization and excitation in the envelopes thrown out by novae and supernovae. He developed methods to compute the decay time of star clusters and the time for establishment of statistical equilibrium in double star systems. In 1947 Dr. Ambartsumian discovered the existence of unstable stellar associations, which led to the conclusion that star formation, is still taking place in the Galaxy.^[1]

The following interview was recorded on 2 October 1987 at Dr. Ambartsumian’s office in the Presidium of the Armenian Academy of Sciences in Erevan. It concerns the early days of Dr. Ambartsumian’s career and the state of Soviet astronomy in the 1920s and l930s. The interview was conducted in Russian, and the text that follows is an edited and abridged translation of the transcribed interview. The author’s questions are indicated by “McCutcheon” and Dr. Ambartsumian’s responses are denoted by “Ambartsumian” Square brackets are used to indicate the author understands of Dr. Ambartsumian’s thoughts that were not fully stated at the time of the interview.

The author wishes to thank Dr. Donald Osterbrock of Lick Observatory and Dr. Mikhail Kazarian of Erevan State University for their aid in arranging this interview and Ms. Lyuba Rabinovich for her help in verifying the accuracy of the Russian transcription. This interview was recorded while the author was a participant on the 1987-88 US-USSR Long-term Exchange of Advanced Researchers administered by the International Research and Exchanges Board.

McCutcheon:

I understand that you were born in Tbilisi on 18 September 1908.

Ambartsumian:

Yes, I was born in Tbilisi, old style, on 5 September 1908, which in fact is 18 September new style. At that time in the Caucasus and throughout the entire Russian Empire the old calendar was in use.^[2]

McCutcheon:

What did your parents do for a living? How many brothers and sisters did you have? Did any of them pursue a career in science?

Ambartsumian:

I was born into the family of an Armenian man of letters, Amazasp Asaturovich Ambartsumian. Besides me our family included my brother and sister. Neither of them is living today, but they did study together with me. All was in order. My sister lived to a comparatively advanced age and died a year ago. In her last years she was the chairman of the Department of Probability Theory at Erevan University. My brother died young when he was all of 23 or 24 years old. He was not especially involved in science. He was working in a geophysical expedition as an operator [at time of his death]. My father translated Homer’s Illiad into Armenian. He also translated the Greek tragedies that was one of his largest works. He encouraged me from a very early age to show an interest in knowledge in general and in science in particular. I would say that he was very proud of me and even showed off to his friends that he had such a son who could already multiply when he was all of three or four years old. I can’t tell you precisely now, but I don’t know which I learned first: to count or to speak. Thus my inclination towards arithmetic and mathematics appeared very early.

McCutcheon:

How old were you then?

Ambartsumian:

I was, I think, three or four. By then I could already count very well. As an anecdote I can tell you that I was able to solve problems very quickly. And then the time came for me to go to school. On the entrance exam I had to write the solution to a problem. So, they gave me a problem. Well, for me the problem was unusually simple. I immediately wrote the answer. The examiner gave me a 2, in other words unsatisfactory.^[3] Why? Because it turns out that I should have broken the problem into questions and solved those questions in order. It seems that the problem was considered to be difficult, and one was expected to break it into questions. That is to say, one was supposed to break it up into, “What is the cost of one arshin we didn’t have the metric system then one arshin^[4] of material?” Then, “How much does five arshins of material cost?” And so on and so forth. Each of these questions needed to be answered in turn, but I went ahead and immediately wrote the [final] answer. So they failed me! My father was very angry. He was a very hot-tempered man, and he reacted to this in an appropriately serious manner. “You won’t go to school. You’ll study at home. You will stay home for another two years, and then you will go straight into the senior class.” And I really did stay home for two years. By the way, during those two years I learned Russian well. (Previously I had known it rather poorly.) Then I went into the first class at the gymnasium, which was taught in Russian. What was the “first class?” At that time the gymnasium was like this: first there was the junior preparatory class, then the senior preparatory class, and then the first class. I had tried to enter the junior preparatory class, but now I went directly into the first class. Of course, I now knew by bitter experience that at first one should exhibit, so to speak, a somewhat lower level of knowledge, and then everything will go well! And so during the (entrance) exam I did show a lower level of knowledge, and so everything went well.

McCutcheon:

How old were you when you graduated from the gymnasium?

Ambartsumian:

I graduated from the gymnasium and was ready to enter the university when I was fifteen years old. Actually, I was closer to sixteen. I graduated very early, very early, of course.

McCutcheon:

How did you first become interested in science and, in particular, in astronomy?

Ambartsumian:

Well, I had a love for mathematics, for computations from the very beginning. I can’t even trace how far and deeply this goes into my past. As concerns astronomy, I remember very well how my interest started. When I was about eleven years old I read a book by a certain Mitchel, a Russian translation from English. As I remember, it was called Celestial Bodies.^[5] This book interested me terribly. It was as though I was drunk after reading it. In my soul I was an astronomer from that time onward. I was an astronomer, that is, from age twelve.

McCutcheon:

I understand that you gave public lectures while still in school. How did this come about? Where and on what topics did you give these lectures?

Ambartsumian:

My teachers all knew [about my interest in astronomy]. Indeed, I did give several lectures, first in school and then in the various clubs and houses of culture that were beginning to appear in great numbers at that time. I don’t think these lectures were very good, but my teachers and parents wanted me to show that I had this knowledge. I myself wasn’t particularly aiming to show, to demonstrate that I had such knowledge despite my twelve or thirteen years. On what subjects? Well, for example, I gave a talk on the origin of the solar system and a lecture entitled “Is there Life on Other Planets?” These are the popular sorts of lectures that I gave when I was twelve or thirteen years old. Actually, I gave these lectures right up to age fifteen, when I went to Leningrad to study. At that time I was already studying astronomy rather seriously, because in Tiflis there was a very serious teacher of astronomy, Sudakov.^[6] I transferred to the school where Sudakov was teaching. He had built a school observatory there, and I worked with him in this observatory. Since I was already thinking about the university, I had already begun to acquire specialized knowledge.

McCutcheon:

Was Sudakov a professional astronomer or only a teacher of astronomy?

Ambartsumian:

Nikolai Ignatevich Sudakov studied astronomy in Moscow at the university level, and he shared with me in detail both his knowledge and reminiscences. He told me not to get carried away by all sorts of amateur astronomy, because a specialist must after all be a specialist. I followed his example. He also told me in detail about the relations between astronomers at Pulkovo and in Moscow. The Moscow astronomers used to refer to the Pulkovo [astronomers] as “gods.” By “gods” they meant that the Pulkovo astronomers lived separate and somewhat isolated [from the life around them].

McCutcheon:

How is it then that you decided to go to Leningrad, not Moscow, for your higher education?

Ambartsumian:

The fact is that my father graduated from the Petersburg University, nowadays the Leningrad University. He praised this university very much, saying that it was already a very serious university during tsarist times. Thus it was that I decided to go there. Pulkovo Observatory is not far away, in fact just outside Leningrad, [and that also played a role in my decision]. So it was that at age fifteen my parents allowed me and my older sister to go to Leningrad to study.

McCutcheon:

But why is it that at first you entered the Herzen Pedagogical Institute, not Leningrad State University?

Ambartsumian:

The fact is that I was too late. I didn’t know when the entrance exams ended. I arrived in August, but it turned out that admissions into Leningrad University were already closed. What could I do? They told me that admissions into the Herzen Pedagogical Institute were still open and that there was a physics-math department there. So I enrolled and studied there for a year and a half.

McCutcheon:

Did your sister study there also?

Ambartsumian:

No, not my sister. My sister had a different interest, and she enrolled in a different institute, the Electro-technical as I recall. For many reasons it was rather difficult to enroll [in a university] at that time. One needed a komandirovka^[7] from one or another organization, because the intention of our government was to change the social composition somewhat, make it more democratic. Having or not having a komandirovka from some institution or trade union organization played a role. My situation in this respect was somewhat better than my sister’s. Therefore she was not able to enroll immediately. In the end, a year later, she also enrolled in Leningrad University. Thus, after a while we were both at Leningrad University. But it turned out that I did not lose any time. At the pedagogical institute the specialized subjects were not taught in the same way as at the university, and for this reason many students who entered the pedagogical institute with me later transferred to the university and lost a year in the process. That is to say that they completed the first year in the pedagogical institute and then had to re-do the first year over again at the university. I did not lose anything. I passed all the exams I needed to and thus was a year ahead [of the other students who transferred from the Herzen Institute.]

McCutcheon:

Who were some of the other students with whom you studied at the university?

Ambartsumian:

There was the very famous mathematician, Academician Sobolev the academician, not the astronomer Academician Sobolev.^[8] Then there was also Academician Khristyanovich,^[9] a mechanician. They studied together with me, although they graduated a year later. They are both still working and in good health.

McCutcheon:

What were your main courses at Leningrad State University?

Ambartsumian:

Well, it is quite clear that at the university I was interested in both astronomy and mathematics. I loved mathematics, but at the same time I felt that my profession would be astronomy. Mathematics was like a hobby, but I did complete the full mathematics curriculum. Thus you could say that I graduated with a major in mathematics, but in fact it is recorded that I graduated as an astronomer. McCutcheon: So you could say that you had two majors, one in mathematics and one in astronomy?

Ambartsumian:

Yes, you could say I had two majors, because if you look at the set of exams I passed, then you would see that I passed the complete set of exams in mathematics. But the final documents I would like to tell you in somewhat more detail about the final documents. When the time came to graduate, my friends said, “Let’s go and receive our diplomas.” I replied, “No, I’m not going.” Why was that? It was because my father had said that one should study not for the sake of a diploma but for science. So it was that my friends went to receive their diplomas, but I did not. I did defend my undergraduate thesis, however.

McCutcheon:

What was the subject of your thesis?

Ambartsumian:

I don’t remember the exact title, but it was devoted to a study of radiative transfer radiative equilibrium as they used to say. Well, fifty years went by after I completed my university courses in 1928. Then, in 1978, I returned to the university and said I would be happy to receive my diploma. Thus it is that fifty years after the fact I can show my grandchildren that one can study without necessarily receiving a diploma. R.M So in the end you did receive your diploma?

Ambartsumian:

I did receive it, and it is written on the diploma that I graduated in 1928 but that the diploma was granted in 1978. I show it now with pride, and I am going to give it to one of my granddaughters who is showing great promise in mathematics.

McCutcheon:

Who were your main astronomy professors and what do you remember about them?

Ambartsumian:

I had good professors. Among them was one who especially captivated us students. That was Professor Tikhov.^[10] I would not say that he was a scientist of the highest order, but he had a very captivating personality. He had a bit of an amateur vein in him. Then there was Professor Ivanov.^[11] He was a very dry, boring man.

McCutcheon:

He was a celestial mechanician, wasn’t he?

Ambartsumian:

Yes, he taught theoretical astronomy, spherical astronomy, and celestial mechanics. He was a boring man, but I remembered what my teacher Sudakov had told me in Tiflis. He told me that one should not get carried away by the aesthetically pleasing side of astronomy, the side that interests amateurs. One should not be afraid of astronomy’s dry side. Besides this, in my soul I was, after all, a mathematician, a formalist to a significant degree. Therefore I was also able to listen to Professor Ivanov with great satisfaction. However, he was a boring man indeed. After all, it is possible to talk about mathematics with great inspiration, but he was not that type. He was a somewhat boring man. At that time he was also director of Pulkovo Observatory.

McCutcheon:

Was it at about this time that you first met N. A. Kozyrev,^[12] with whom I notice you had many joint publications during this period?

Ambartsumian:

Indeed, when I entered the pedagogical institute I found a comrade with whom I became friends because we had absolutely identical goals. He was also interested in astronomy. He also wanted to enter the university. He also, for reasons I don’t remember now, was not able to enter the university immediately, and therefore he also enrolled in the pedagogical institute. He later transferred to the university, in fact somewhat sooner than I did. Kozyrev was a member of the Mirovedenie^[13] society, in which there was a circle of young amateurs. He was very involved with the amateurs, and I tried to cool him off somewhat from this. After all, such involvement distracts somewhat from serious work. Well, in general I assign great significance to amateur work in astronomy. You know that this is of course a very important point. Nevertheless, if we wish to become specialists, we must study seriously. I remembered what Sudakov had told me, and I agitated with him [Kozyrev] in this connection. And to an extent he agreed with me. And so we began to work together. I don’t mean just over our course work and so forth. Together we made our first attempts to carry out scientific work. So it was that in 1925 we finished our first scientific paper. It was sometime in August or September; I don’t remember precisely any longer, that we sent it to the journal Astronomische Nachrichten. At that time the network of astronomical journals in the Soviet Union was very weak, and there were very few journals to which we could have sent it.

McCutcheon:

Wasn’t there already the Astronomicheskii zhurnal?^[14]

Ambartsumian:

Yes, but it was so thin and appeared so infrequently that we decided to send our work to the Astronomische Nachrichten. The editor of Astronomische Nachrichten was Professor Kobold, an old astronomer who edited this journal for many years. This journal had already been appearing in Germany for more than a hundred years. All news, all discoveries were printed there. Neither in America nor in the Soviet Union was there such a journal. And so we printed our first article in vol. 226 from 1925.^[15] We received the issue at the end of December and were overjoyed. Just imagine we were young men who were all of seventeen years old! We were overjoyed to think that we had published our work not just anywhere but in an important foreign journal.

McCutcheon:

What was this work about?

Ambartsumian:

It concerned the sun. At first we were both interested by and both worked on the physics of the sun. I wouldn’t say that all our works in this series were outstanding. Allow me along the way I will evaluate those good works that, in my opinion, have retained their place in science as a valuable result and are mentioned to this day. There were also works that had only an ephemeral significance. I believe that in this first work there was not one mistake, formally everything was correct, but it did not have any lasting significance.

McCutcheon:

Besides Kozyrev, who were your other main student colleagues?

Ambartsumian:

Of course we were all student-astronomers, but we were astronomers who went in different directions. One was, let’s say, working in gravimetry and geodesy. I had one very good comrade, Khramov, who died however during the war. He was a very serious gravimetrist. I will tell you about Eropkin separately when I come to the Commission for Study of the Sun.

McCutcheon:

How well did you know Gamow, Landau, and Ivanenko?

Ambartsumian:

Of course I associated with physicists also, and I did know Gamow, Landau, and Ivanenko.

McCutcheon:

But they were really in a different area from you?

Ambartsumian:

Yes, they were in a somewhat different area, but some of them, particularly Ivanenko^[16]and also Bronshtein^[17]tried to interest me in and attract me to the study of physical problems in particular, Ivanenko.

McCutcheon:

Did you have any joint publications?

Ambartsumian:

Yes we did. There were both good and bad works, but there was one that was especially good. Ivanenko and I published a work what that proved for the first time that there are no electrons in the nucleus of an atom.^[18] At that time it seemed that if the helium nucleus has a weight of four and a charge of positive two, then there must be four protons [in the nucleus], because the neutron was as yet unknown. It was thought that everything, the whole world consists only of protons and electrons. And so there would be four protons and two electrons. There must be two electrons, absolutely there must be two. Then, working on the problem of Beta decay, we came to the conclusion that during Beta decay an electron is created, apparently, at the time of its ejection. In other words, we came to the conclusion that electrons obviously do not exist in the nucleus. They are in some sort of disguised form. There were no neutrons then, and therefore we couldn’t completely understand how this takes place. Now we all know simply that an electron and proton are united in a neutron. Therefore, electrons do not exist [in the nucleus]. So we published an article that proved that an electron can be created during Beta decay. Then, when the neutron was discovered, Ivanenko published an article, somewhat under my influence you might say. I said that this was so obvious, so elementary that I didn’t even want to write about it. But he said that he would love to write about it. I said that it is completely obvious that the nucleus consists of protons and neutrons. And then Heisenberg published a similar article. The articles by Ivanenko and Heisenberg appeared simultaneously. Well, I don’t consider this one of my main works, but it was very interesting. It was a very active, exciting time. Then I carried out another work to which I assign great significance but that also does not relate [directly] to astronomy. With this I will finish my non-astronomical works. As an astronomer I am interested in the fact that all our knowledge of stellar physics, of the physics of stellar atmospheres, is founded on spectra. The stars speak to us using the language of spectra. But to what degree is this unambiguous? In other words, could there not be some other meaning than that which we assign? Can one form an opinion unambiguously on the basis of spectra? Just then there appeared the works of Heisenberg and Schrodinger, who view the questions of atomic spectra and atomic energy levels as problems of the eigenvalues of several operators. Consequently, the question arises; to what extent does the eigenvalues themselves determine the operator? That is to say, to what extent does the spectrum of an atom determine its structure? That is the “inverse problem.” This was the first time that this problem arose. Mathematicians are studying it until now. Given an operator, find the eigenvalue and the eigen functions. This is the problem that turned out to be the most important in the wave mechanics of Schrodinger. But isn’t it possible to pose the problem inversely? If the eigenvalues are known, is it not possible to first find the operator and then unambiuously determine the [the eigenvalues]. This problem was posed first by me. Of course, I couldn’t solve it completely solved only a very special case, proving a very interesting theorem that among all strings [e.g., of a musical instrument] only a homogeneous string has eigenvalues that are specific to it. That is to say that strings also have a spectrum of eigenvalues. What does this sound like? Well, as I said at the time I received the Lomonosov Prize, if an astronomer carries out a work in mathematics and prints it in a physics journal, then of course no one is going to read it. (I printed my article in the German journal Zeitschrift fur Physik around 1930 or perhaps a little earlier in 1929.^[19]) It is just a case of some unknown young astronomer who is printing a mathematical work in a physics journal!

McCutcheon:

Why did you publish it there?

Ambartsumian:

Out of habit I gave a physical significance to the problem. Well, no one paid any attention. It was only fourteen or fifteen years later that a Swedish mathematician discovered my work and carried out a big study on this subject. After these, such studies became very fashionable, and finally Soviet mathematicians [also] began to study this problem in earnest.

McCutcheon:

So you became a mathematician again?

Ambartsumian:

Yes. Several years later, after the war, I was a member of the Lenin Prize committee, and I voted to give [these mathematicians] a Lenin Prize for these works. In fact, this work had begun seventeen or eighteen years earlier, and this was very pleasing to me. That, so to speak, was my significance in mathematics.

McCutcheon:

Getting back to the end of the 1920s and the start of the 1930s, were you a member of the Russian Amateur Mirovedenie Society (ROLM)? Did you know any of the leading members of this society, such as N. A. Morozov^[20]or D. O. Svyatskii^[21]?

Ambartsumian:

Of course I did know several of the society’s leaders, but I was not closely connected [to the society]. With Svyatskii I had only a nodding acquaintance. We would, perhaps, greet each other; inquire about each other’s health, and so forth. Tikhov was associated both with ROLM and the Lesgaft Institute. I used to go frequently to the Lesgaft Institute, which was located in the same building as ROLM. There I would reduce plates taken by Tikhov on the [Pulkovo] normal astrograph. This gave me the feeling that I was occupied full-time, so to speak, with the reduction of astronomical observations.

McCutcheon:

But you would not consider yourself to have been an active member of ROLM?

Ambartsumian:

No, I was not very active in ROLM. Kozyrev, on the other hand, got his start in ROLM. However, he later came to view it in about the same way as I did and no longer was an active member. ROLM did, of course, carry out a tremendous amount of work in amateur astronomy and in gathering amateur observations, which play a large scientific role in certain areas, such as variable stars, meteors, and so on.

McCutcheon:

It seems to me, however, that ROLM was a more serious society than many other similar amateur organizations.

Ambartsumian:

Yes, it was.

McCutcheon:

For example, the society’s journal, Mirovedenie, seems to have been about on the same level as the American journal Popular Astronomy.

Ambartsumian:

Mirovedenie was a serious journal also, very serious. Later the active members of ROLM began to work elsewhere. Besides this there seem to have been some political factors. Apparently there was some dissatisfaction with the society and at some point the society ceased to exist.^[22]

McCutcheon:

But Mirovedenie continued to be published. Do you have any recollections of V. T. Ter-Oganezov^[23] who became the editor of Mirovedenie in 1930? I have heard that he was of Armenian descent. Is that correct?

Ambartsumian:

Yes, Mirovedenie continued to appear, and V. T. Ter-Oganezov, who lived in Moscow, became its editor. Ter-Oganezov was an interesting individual. Yes, he was of Armenian descent, Ter-Oganezyan, Vartan Tigranovich, as I recall. He was not a very well educated man. His career was such that he worked in the Commissariat of Education, in Glavnauka^[24] and other such government organizations.

McCutcheon:

Was he an astronomer?

Ambartsumian:

He had a Moscow education.^[25] Moscow University always differed from Leningrad University in that it had more of a social [obshchestvenyi] spirit. As a result there were undoubtedly several cases where specialists entered the public life and ceased to be specialists. I think that Ter-Oganezov was such a person. The amateur spirit remained very strong in him. Also, at that time there were very few Communist Party members among us astronomers, and he was one of those few who was a Party member. He was sincere. [He was a Party member] from the very beginning of the Party’s organization, perhaps even during the pre-revolutionary period. He had great hopes that Party ideology, in particular the ideology of dialectical materialism, would play a larger role [in astronomy]. However, he did not know the new astronomy very well. You see, one must always move forward. If we want one ideology or another to gain greater significance, then that ideology must lead us forward.

McCutcheon:

And Ter-Oganezov lagged behind the times?

Ambartsumian:

That was the case, but indeed he was the editor [of Mirovedenie]. On a couple of occasions he asked me to write articles for Mirovedenie, and I did this for him.

McCutcheon:

After completing your studies at Leningrad State University, how did you go about becoming a graduate student at Pulkovo Observatory?

Ambartsumian:

Well, that came about in the following way. I believed I needed to become more of a specialist so that there wouldn’t be this amateur spirit. Therefore both Kozyrev and I went to Professor Ivanov, who was simultaneously our professor and director of Pulkovo Observatory, and asked him if we could become graduate students at the observatory. He gave his approval and also agreed to be one of our advisers. Belopolskii^[26] was another. I had already become acquainted with Belopolskii somewhat earlier when I was carrying out my practical work at Pulkovo Observatory. What do I mean by practical work? During the summer of 1927 we carried out our practical work at Pulkovo, and I was with Belopolskii. I observed the sun and so forth, and I saw of course that Belopolskii was one of the greatest astrophysicists not only in our country but in the whole world. I was convinced of this even earlier [before my practical work] from having read his work. This is the man who, for example, was the first to discover the pulsation of the Cepheids. Those are the types of major discoveries he made in astronomy. Therefore I had great respect for him. Belopolskii agreed to be my adviser, but that was on paper only. I already had a very well defined direction [for my research]. I wanted to work in the area of theoretical astrophysics, which had not existed in the Soviet Union before that time. There were no specialists in this area.

McCutcheon:

There was only observational astrophysics?

Ambartsumian:

Yes, only observational. There was no real theoretical astrophysics, although Fesenkov^[27] also to some extent did carry out theoretical works. That was Academician Fesenkov, who lived one generation before me.

McCutcheon:

At that time wasn’t he the director of the Shternberg Institute in Moscow?

Ambartsumian:

Yes, in Moscow, it seems, he was director, but I don’t remember for how long. He became an academician later. Of the Pulkovo astronomers Belopolskii was the best. I repeat again, however, that I was to a great extent independent, because I was interested in theoretical astrophysics. Belopolskii was a very intelligent man with great talent, and he saw that the best thing he could do was not interfere with me. And that is what he did.

McCutcheon:

Who were the other graduate students at Pulkovo besides yourself?

Ambartsumian:

I have already mentioned Kozyrev, who was without a doubt a very talented person. I would also like to mention Ponomarev^[28] as a very talented person, a designer of telescopes, who was also a graduate student under Belopolskii. He too was a very independent person, however. He built the first Soviet reflector, the one that was mounted at the Abastumani Observatory.

McCutcheon:

How was it that you became the scientific secretary at Pulkovo?

Ambartsumian:

They appointed me scientific secretary after I completed my graduate work. I wouldn’t say that I was very successful in this position.

McCutcheon:

Did this involve primarily administrative work?

Ambartsumian:

Administrative work? Yes, to a great degree. A scientific secretary must be very thorough and precise. I have yet in my life to learn thoroughness and precision. If I had gone into observational work I would have learned these traits more. I consider myself to be a bad organizer because of my insufficient thoroughness. Nevertheless, my friends consider me to be a good organizer. Why? Because I have the ability to captivate the people who work with me. I must admit that at times I do feel in myself the ability, so to speak, to captivate people. However, if I have to organize something from one time to another, I am not able to do it. This is my shortcoming.

McCutcheon:

They do say, however, that a person who is able to inspire others to work is by definition a good administrator!

Ambartsumian:

Well, if they have put up with me here in the observatory for forty years, for forty years mind you, then perhaps I am not that bad an organizer after all. Nevertheless, I would like to say that I do have this deficiency as an organizer: my lack of thoroughness and precision.

McCutcheon:

During your time at Pulkovo did you visit Pulkovo’s southern stations in Simeis or Nikolaev?

Ambartsumian:

No, I never visited the Nikolaev division, but I did visit the division in Simeis. In Simeis I worked together with Shain^[29] and carried out one of my observational works. I never would have been able to carry out observational work well on my own because of this trait, my lack of thoroughness and precision. But together with Shain I did carry out (observational work). I had an interesting idea concerning planetary nebulae. They radiate emission lines but are extended objects, not stars. Now, if space were empty, if there were no absorption, then surface brightness would not depend on distance. That is to say, if one were to move a planetary nebula further away, its dimensions would become smaller, but the surface brightness, the brightness per unit area, would not change. Absorption can, however, exert an influence, and thus I asked why no one had studied this question of surface brightness. I proposed to Academician Shain that we determine the surface brightness in monochromatic images for several emission nebulae. For this work we used the one meter telescope of the Crimean Astrophysical Observatory, which at that time was the largest telescope in the Soviet Union.^[30]

McCutcheon:

I understand that you are married to the daughter of Academician Shain. Is that correct?

Ambartsumian:

No, not to his daughter but rather to a member of Academician Shain’s family, to his wife’s niece, who lived with them in the Crimea. Vera Fyodorovna Ambartsumian is in good health to this day. We have a large family.

McCutcheon:

How many children do you have?

Ambartsumian:

By now we have a whole tribe, because I have four children, eight grandchildren, and great grandchildren as well.

McCutcheon:

In general, how would you characterize Pulkovo Observatory and your life there in the late 1920s and early 1930s?

Ambartsumian:

I am very thankful for my time at Pulkovo. On the other hand, Pulkovo was a very old institution, and for this reason there were certain elements of ossification and stagnation. Nevertheless, this was the best qualified astronomical institution in the Soviet Union.

McCutcheon:

The specialty there at that time was still astrometry, was it not?

Ambartsumian:

Yes, astrometry. There was still the influence of the old school, the old German school. I mean that in the good sense. I remember there was Rents^[31] who was of German descent. He was one of those very pleasant astronomers who constantly, with great precision, continued to observe and so forth despite his very advanced age. All of this was very good.

McCutcheon:

During this period how closely did Pulkovo cooperate with the other two main astronomical centers in Leningrad, the Astronomical Institute^[32] and Leningrad State University?

Ambartsumian:

In general, of course, relations between the various astronomical institutions of the Soviet Union were not bad. But along with this I must say that we did have one deficiency that has lasted until now. It would seem that in the Soviet Union all institutions belong to the government. Nevertheless, our deficiency is that we coordinate things poorly. Taking this into account, we organized the Astronomical Council.^[33] It was headed first by Fesenkov and then by Mikhailov.^[34] This helped us quite a bit.

McCutcheon:

How did you meet Dr. Chandrasekhar? I understand that he visited the Soviet Union in 1934. What recollections do you have of his visit?

Ambartsumian:

Yes, Chandrasekhar really was in the Soviet Union in 1934. It was a great pleasure to receive him here, and I took an active part in this. I was still at Pulkovo at the time, but I was already preparing to leave it for good.

McCutcheon:

Why was it that you decided to leave Pulkovo and return to Leningrad State University?

Ambartsumian:

I was already teaching part-time in the university and working part-time at Pulkovo starting in 1931. I left Pulkovo in 1934. I liked teaching theoretical subjects, theoretical astrophysics. I lectured on theoretical physics for astronomers and astrophysicists. I immediately had many students, and now I would like to say something about them. From the first series of students I should mention Dombrovskii.^[35] This is the man who with the aid of theoretical observations discovered the strong polarization in the Crab Nebula. By the way, he also discovered the polarization of stars in general. However, the polarization of stars was discovered by an American astronomer also. Dombrovskii’s methods were coarser and so it turned out that he is not considered to be the discoverer. Although [their work] was carried out simultaneously, the American astronomers have an advantage when they lay claim to this discovery, because they used more refined methods and consequently their work was more convincing. They used photoelectric methods, whereas Dombrovskii used photographic. Then he switched to photoelectric methods and discovered the polarization in the center of the Crab Nebula. The whole world recognizes this to be a brilliant discovery. Besides Dombrovskii there was the Georgian Vashakidze^[36] who also carried out interesting works. Then there was Markaryan,^[37] who carried out his graduate work under me.

McCutcheon:

When was he your graduate student?

Ambartsumian:

He was my graduate student in the very last years before the war. However, although you can approach this question in various ways, I consider my most brilliant graduate student to have been Sobolev,^[38] who is now an academician.

McCutcheon:

Centralized planning of the Soviet economy was introduced during the first two five year plans. When was it extended to include astronomical research? What did planning mean in practical terms for the day-to-day operation of an astronomical observatory?

Ambartsumian:

Although the expression “centralized planning” is used in Soviet astronomy, in fact this means that each institution develops its own plans, and then these plans are coordinated [with those of other institutes]. In this sense centralized planning is provided through the Astronomical Council. Now, however, things have been complicated somewhat, because alongside optical astronomy in the post-war years it also became necessary to plan radio astronomy research. Then space research and x-ray astronomy and so forth appeared. With time everything has become more and more complex. After the war the necessity of having more generalized coordination appeared. That is when the United Council on Astronomy was founded. I had the honor of chairing this council until recently. At the beginning of this year I gave up my chairmanship to my student Sobolev. I know I have gotten carried away, but there is one thing that is very important. It is the following. We are the old generation of astronomers. I am now one of the oldest astronomers here. Before the war I was not part of the old generation. I was comparatively, relatively young. But look what happened. Our students went off to the war, and many of them perished. In actuality we lost an entire generation, and so our continuity was broken. In the West, perhaps, people do not understand the difficulties we lived through. Because of this the old cadres remained at the leadership of Soviet astronomy longer than was necessary. This is my opinion. Perhaps not everyone will agree with me, but this did play a very big role. This perestroika that everyone is talking about could help us quite a bit. We need to organize this transition somewhat faster. We need to transfer [our leadership posts] to the next generation, and the fact is that my generation virtually does not have a successor that is, let us say, fifteen years younger than it.

McCutcheon:

There is only an old generation and a very young generation with no middle generation?

Ambartsumian:

Yes, and this is very bad, because it makes it more difficult for us to understand each other. These are the difficulties that we are finding.

McCutcheon:

Perhaps you could say, as they say in English, that you have a generation gap?

Ambartsumian:

A gap? That is absolutely correct. When we speak of generations in science, then I believe that the change of generations should take place not very twenty or thirty years, but rather every ten or fifteen years. Just take a look. Both Sobolev and Markaryan are my students. They were no more than ten years younger than me, and Markaryan has already died. Of course, this is because I became a professor and a teacher very early, and therefore my best students were not that much younger than me. Also, I was a more inspiring teacher then, and for this reason my best students came from these first series. It is for this reason that I believe that ten or fifteen years, not twenty or thirty, [is the correct time interval for the change of generations]. Now the development of science has speeded up, and this means that the change of generations takes place very rapidly. And, I will tell you directly, we have a problem. For example, there is the question of being able to use information technology, which is indispensable for the modern astronomer. My generation has only modest experience [in this area], and as a result yet another generation does not have an active ability to use information technology. They did not have the chance to learn. The next generations will be able to use it very well. Only those people who are able to use information technology are able to work in modern astronomy. As you know, astronomy accumulates such a quantity of data that it is difficult to preserve them in one’s head. Therefore data banks and so forth [have become very important]. Reduction methods, the mechanical methods of computing, and the science itself are different. The character of astronomy has changed greatly in the past fifteen years. Thus I live with interest and hope that the next generation of younger astronomers will be able to carry forth this work for real, better than us. I hope that astronomy will flourish even more but, at the same time, that something will remain for an individual to study using just his own mind and feelings. I hope that an individual will still be able to obtain practical results. Astronomy has acquired great practical significance. Astronomy has great practical, ideological, and purely scientific significance in that astronomy has a strong influence on physics and mathematics. For example, I as an astronomer happened upon the idea of inverse problems, and now in England the journal Inverse Problems is being published. I came to this problem through astronomy. The stars speak to us using the language of spectral lines. Not only the stars speak using the language of spectral lines. So do atoms not just atoms in stars but also atoms on the earth. From here you get inverse problems and physic-astronomy. So you see that astronomy has a strong influence on everything. I will end on that note, but perhaps you have one or two additional questions?

McCutcheon:

Thank you very much for your detailed answers, which I found very interesting. I am certain that astronomers and historians in the United States will find them interesting as well, particularly as regards your early years in Leningrad and Tbilisi. Earlier you mentioned that you would talk about the Commission for Study of the Sun.^[39] Could you say a few words about that now?

Ambartsumian:

Yes, of course. The commission was created under the chairmanship of Belopolskii. Eropkin,^[40] with whom I studied in the university, was the secretary. He was a very capable, enterprising man. What were his interests? Well, he was interested in the sun in all of its aspects. He had this one deficiency, that once he had started work on this problem, he needed to unite all the sun’s systems into a whole. Of course, now, with time, we have come to this slowly. The Council for the Study of Solar and Terrestrial Interaction is concerned with this. In the beginning this council was called the Commission for Study of the Sun. Eropkin was most interested in atmospheric ozone. He had several ideas that have become very important today. In particular, is it possible that some actions, perhaps even natural processes, will deplete the ozone layer? For this reason he was also interested in laboratory studies of ozone. He worked on this together with the physicist Kondratev,^[41] who later became an academician. (Kondratev worked at the Physical-Technical Institute, which later became the Ioffe Institute.) They studied the spectrum of ozone and carried out other studies of this sort. Gradually our solar investigators, particularly those in this commission, became interested in solar activity and the sun’s effects on the earth. (This commission later became the Commission on Solar-Terrestrial Interaction). In this connection, studies of the earth’s magnetic field have played a large role and so on, but I have lost sight of what they are doing now. It is all far from me. Only insofar as I was chairman of the Combined Committee, where they occasionally give reports, do I know how their work is progressing.

McCutcheon:

I have one last question. I understand that even when you were in Leningrad you were working to help the development of astronomy in Armenia. It seems there was already an observatory in Erevan at the end of the 1930s. Could you tell me what you were doing to help here in Erevan at that time?

Ambartsumian:

A small observatory had already been built at the university, and I helped in the sense that I sent a small nine-inch telescope from Leningrad. Here they carried out variable star observations. However, before the war this observatory did not rise significantly above the level of amateur variable star observations. During the war they also carried out photographic observations of variable stars using a small camera, and this was somewhat better. At that time photographic observations were considered to be somewhat better than amateur observations. Now, of course, amateurs also carry out such observations. Then, in 1946, Byurakan Observatory was founded.

McCutcheon:

Was Byurakan opened in 1946, or was that when construction began?

Ambartsumian:

No. 1946 is when construction began, but we began to carry out observations simultaneously. Our instruments stood under the open sky, covered with tarpaulin. Then we had a very good telescope, an eight-inch Schmidt. This is the instrument that Markaryan used to take very good photographs, and it allowed us to carry out a classification in connection with the idea of stellar associations and of star clusters in general. These photographs were very useful, and they were published in an atlas of open star clusters.

McCutcheon:

Thank you again for spending so much time with me.

Ambartsumian:

You’re welcome, you’re welcome. When you return, please give my greetings to all American astronomers.