Interview with Jesse L. Greenstein on 13 January 1980

Sullivan: 00:00

Okay. This is part two of interview with Jesse Greenstein at his home in Pasadena, California. Part one is at the same place only four-and-a-half years ago. So let us start at the review that you did with Grote Reber, and it was published in 1947. This is the first review in radio astronomy. Can you try to put yourself at that time and look at the sweep of the field?

Greenstein: 00:27

What happened was that with the return to university life, the people who had been at the MIT Radiation Lab and the first mentions without much publication - it first mentions of work during the war on advanced microwave technology - I got again interested in radio astronomy as a potentially new and very hopeful-looking science. And since Reber knew many of the people from his work in whatever it was he did for a company near Chicago, and since we saw each other perhaps every other month or so, just natural course of events from Yerkes to Wheaton, Illinois, it seemed to be a good idea to get together as much information, either unpublished or available, by conversation with a few friends. And I didn't know too many people in radar, especially in the MIT Radiation Lab, except Al Whitford, who had worked there, and a few younger people. But I really knew nothing of that work. So it was an education time, and Reber did much of the first spade work trying to find out who had done what. He was certainly not the kind of person who would write a general review and so it seemed very easy for us to get together. And I believe that I wrote the editors of The Observatory and said I was going to do this with Reber and would they refer any new submitted publications to us. And some such things, in fact, did happen. It was before sort of the subdivision of British radio astronomy and warring camps occurred. And so I think we got quite a lot just by correspondence from various people. I remember certainly J. S. Hey's name from that time. I spoke to somebody. A physicist from the University of Chicago whose name I do not remember, who was at the Radiation Lab and he told me first about the Dicke radiometer. And oddly enough, my earlier interest in how much radio static we could explain-- the main trouble is you didn't know what the units meant and you did not have any decent calibration. So I remember talking quite vehemently about the need for accurate calibration of flux densities, as we now call them.

Sullivan: 03:43

Brightness temperatures.

Greenstein: 03:44

Brightness temperatures. With the new antennae. All the antennae were different. And so somebody told me, and I wish I could remember, how they had a Dicke radiometer and they had a small portable, perhaps must have been a foot, foot and a half, diameter dish up on the roof of MIT. And they pointed it horizontally, and they tried out the temperature of the atmosphere, and they interposed a piece of cardboard to see what difference it made.

Sullivan: 04:16

Right, right. Well, this is something that Dicke did with his group just after the war.

Greenstein: 04:20

Well, somebody told me about it, and so I think we mentioned, in fact, that they review the Dicke radiometer and that seemed to me one of the important things.

Sullivan: 04:32

And there is some care in there about, indeed, this business of calibration. You have some correspondence with Townes that you mentioned about how to interpret Jansky's measurements and--

Greenstein: 04:41

Yeah. Well, you see, we had been bitten badly by our lack of knowledge of practical electromagnetic or electrostatic units. But more seriously was that nobody much cared because if they got a signal, that was a miracle. And in particular, therefore, you could not compare energies at different wavelengths and [crosstalk]--

Sullivan: 05:01

Right. Would you think it's fair to say that Reber didn't care?

Greenstein: 05:05

Reber, I think, could not have cared very much, to be honest with you. But I believe there was a way of putting some kind of what they call a load, a balance resistance load or something. But, of course, it was effectively at or near the focus rather than infinity, unlike the radiometer, where you really compared a final beam with a load that was internal but in a similarly columnated way so that there was null effect on switching if you're at the right low temperature. I think he didn't care terribly. I think he does have calibration. It's unfair to say he didn't care, but since there was nobody else to compare with, it didn't matter enormously to anybody. For example, I didn't know until your symposium, I didn't remember, certainly, that he had started at much higher frequency and gone back until there was a signal and I think the idea of just getting enough signal was terribly important.

Sullivan: 06:17

Right, right.

Greenstein: 06:19

In any case, we did have, I think, given the times and how early it was, good cooperation from the British and leakage of stuff, some of which was still probably classified, from the Radiation Lab and names that became famous later which I just heard for the first time, since I had nothing to do with it. It's rather odd that afterwards the head of the Radiation Lab became Caltech's president and the man who spent a year or so there before he went to Los Alamos became the head of the division with whom I worked later. And both were instrumental in working in the Caltech side to get radio astronomy started. They'd both been Radiation Lab people, but I knew neither of them in '47.

Sullivan: 07:08

Well, if you could just say who they are for the record.

Greenstein: 07:10

[Lee] DuBridge, who was head of the Radiation Lab and [Robert] Bacher, who was there for a while, I think was associated with deputy director and then went to Los Alamos.

Sullivan: 07:22

So in 1947, you were able to write a 12 small page article that pretty much covered all of radio astronomy.

Greenstein: 07:29

That's right. Everything we could find. And in fact, it's in two pieces because for some, I think Reber got a job or a different thing and there was an addendum of stuff that kept coming in later, which I wrote, but we were pretty equally responsible and I think it's fair to say that it was his knowledge of some people in the field and what had been going on in the classified area that gave me the first look at what had been done during the War, what was done afterwards. We were rather interested in a thing which doesn't appear there, I believe. It may never have appeared. We heard that the Japanese had made experiments using small explosive charges in a laboratory room and detected pulses of electromagnetic energy, which are presumably, now thinking back, actually some kind of convected charge transport and a shockwave. So you have a blast wave, and then the atmosphere, it might be hot enough to give you a small ion content, and the electrons and ions separate. And that was one of the things that I found very intriguing. Again, looking for a source of the energy. I don't know if that's in.

Sullivan: 08:55

I don't think so. But you thought that maybe the radio emission might be due to a bunch of little explosions or whatever.

Greenstein: 09:00

Yeah, explosive events or-- and in a sense, it's the idea of a moving, charged plasma in modern words. We also heard, and since there, Reber was well connected, that a lot of amateurs, which other people have mentioned, had heard strange radio signals, including some in Japan. So right after the War, we got a little, and that's our only insight into the Japanese effort.

Sullivan: 09:31

What about the solar work at that time? And of course, your work has never been directly solar, but can you remember what you made of the solar bursts and so forth?

Greenstein: 09:41

[inaudible]. From the point of view of having  confidence with an ax to grind, i.e., if you don't know where the energy comes from, it's not much use. Which doesn't agree with how the science developed which was to detect the waves and later argue about where they came from. The real problem was that the Sun was not well behaved most of the time. Reber had had this strange experience. I don't know if it's after the article or before of getting the sun in a side lobe during a major solar burst when he was pointed to 80 degrees or something from the Sun. Do you know the story?

Sullivan: 10:26

No. I don't think I've heard this one, no.

Greenstein: 10:28

Well, it may have been right after the article, but he was approached very early by the Carnegie Institution of Washington to perhaps come and do radio astronomy under normal research auspices. And as I remember the story, it's very vague, he in fact, had a visit from some people from Carnegie, which I had nothing to do with. And his apparatus misbehaved grossly, and instead of showing the transit of either Cygnus or Sagittarius A, he got all kinds of noise and hash on his recorder, and he was terribly embarrassed. And it turned out that later he read that there had been a major solar flare and outburst, and he had, in fact, got the solar radiation essentially for the first time. The reason for Carnegie Institution of Washington interest in Reber was that at Carnegie originally, both Merle Tuve and Larry Hafstad, who would become research director of General Motors later, had done the first ionospheric sounding work. And their knowledge of that kind of swept frequency device and actually, I think a detection of a ship on the Potomac by accident, was one of the things that North American radar allowed well, I think out of Merle Tuve, very broad interest in absolutely everything. He being, I think, then head of the Department of Terrestrial Magnetism at Carnegie. There was this approach to Reber. And I think somehow this got in the way of the end of that article. And so we never went beyond that. In any case, I left only a year or so after it actually appeared.

Sullivan: 12:32

Let's talk about this AAS symposium. Can you tell me what you remember of that?

Greenstein: 12:35

I remember nothing. I'm glad that you brought it to my attention. The only hypothesis I can make is that in connection with AAS meeting--

Sullivan: 12:46

In late '48.

Greenstein: 12:48

Yes. This is a release dated December 30th, 1948. And it wasn't Yale. There was a mini-symposium in which the speakers were myself, Ralph Williamson, who was then at the David Dunlap Observatory, but who had been a student at Yerkes, a graduate student, and John Hagen, then Mr. John Hagen, I see of the Naval Research Lab. And clearly, John Hagen would have been talking - though I don't have the data about that - on solar radio emissions, which much later became his thesis when you could see between solar bursts to see what the quiet sun was, work at the suitable frequencies to see the lower corona chromosphere. So it looks to me from that list of speakers that it was the first getting together of the few people except the radar experts who were going to be interested in radio astronomy.

Sullivan: 14:05

In an astronomical context.

Greenstein: 14:06

Yes, in a purely astronomical context. Ralph Williamson was, in fact, a purely theoretical astrophysicist who had worked with Chandrasekhar. He was very quiet and gentle personality and given to good mathematical theoretical work applying atomic physics concepts. And I forget what his thesis was about, but perhaps it was stellar interiors with Chandrasekhar. And--

Sullivan: 14:42

This is rather different, though.

Greenstein: 14:43

Yeah. But now, again, you must remember that atomic physics and theory of opacity of matter and stellar interiors have a relation to the then prevalent ideas and are still valid and important ideas of the absorption of radiation and its reemission at any frequency. And one of the things that Williamson did, in fact, I believe I'm correct, was a study of the opacity of the negative hydrogen ion, which was important for stellar atmospheres doing, a purely quantum mechanical computation. And again, because we were trying to fit things into the framework of thermal radiation from hot objects, it was relevant. And Hagan certainly knew of radio bursts, but unfortunately was trying to explain solar radiation by thermal mechanisms. But all in all, these were important people. And John stayed on for a long time.

Sullivan: 15:53

Well, Williamson collaborated with Seeger on the galactic background and mapping it and so forth, sort of galactic structure.

Greenstein: 15:59

That was at Cornell. But that was appreciated later, wasn't it?

Sullivan: 16:02

One or two years later.

Greenstein: 16:04

One or two years later. Apparently, he had gotten a job back in Canada after the War because I remember him as a student at Yerkes during the War. In particular, he acted in some of my wife's community theater things in which we ran during the War with no male help to speak of since everybody was drafted. Williamson was a very serious scientist as I remember it. Also, for many years, he worked at Los Alamos on opacity problems, which is important in radiation trapping and fireball.

Sullivan: 16:43

And one final thing that you mentioned was that, in fact, we found that you were a councilor of the AAS at this time, and probably therefore--

Greenstein: 16:51

That's right.

Sullivan: 16:52

I want to organize this session although you can't remember it.

Greenstein: 16:55

I don't remember it, and it seems natural. Actually, one of the reasons I'm almost certain the meeting was at Yale was Lyman Spitzer. And again, Lyman's work had been in anti-submarine warfare. His knowledge of that part of theoretical physics relevance was the earliest knowledge that came into astrophysics or plasma physics as such. And at this same meeting, I'm pretty sure Lyman, having had half of a drink because it didn't take much, did the dance of an excited electron in an intense magnetic field, which was essentially how you get trapped on a field and has some ultimate reference to the future plasma fusion research, which Ian Schwarzfield started. I'm almost certain it was because Spitzer had gone to Princeton that the meeting was there. Because the meeting a year or two organized after the War, this thing had to be organized within a year after people had left the War work. It depended on individuals very much.

Sullivan: 18:13

You mean Spitzer was at Yale at this time?

Greenstein: 18:14

At Yale. Spitzer was a junior professor at Yale. Okay.

Sullivan: 18:20

Okay. So you went to Yerkes, and then how long were you there? What I should say is, when did you leave Yerkes?

Greenstein: 18:32

I left Yerkes in mid June 1948, so I was already out of Yerkes and at Caltech and Palomar Mt. Wilson.

Sullivan: 18:52

The next reference I then have to a publication of yours involving radio astronomy, although you may have been thinking about these things, was in 1953 with Rudolph Minkowski on the Crab Nebula.

Greenstein: 19:07

Okay. You have the references, earlier work with the Yerkes group?

Sullivan: 19:16

Oh, yes, we talked about that last time. We talked about--

Greenstein: 19:19

Somewhere around there we mentioned bound-bound transitions, which I thought looking backward was rather perceptive, only we didn't follow it up. Anyway, I went to Caltech. Radio astronomy had to stand aside for a while because I was in a place where I had enough to do, and that was to start the department and to get a staff for the newly completed Palomar Observatory.

Sullivan: 19:58

Was there no Department of Astronomy before?

Greenstein: 20:00

There was no Department of astronomy. There had been a Ph.D. in astronomy in an astronomical subject done by a student in the physics department, Olin Wilson, who retired only recently from Mt. Wilson Palomar staff. And he was the first Ph.D. in radio astronomy-- in astronomy, but he was a physics student. There was one legal astronomer in the department, that was Fritz Zwicky, who had been a physicist and become interested in astronomy. There was a teacher of elementary astronomy, a course on solar system, essentially, and that's all. And I came to a large empty building filled with a residue of research from World War II from John Strong. John Strong's first vacuum pumps were still in the basement, all crystallized, and had to be disposed of, and samples of almost every element in the periodic table that Strong had tried in his early experiments on aluminizing mirrors when he was a professor at Caltech.

Sullivan: 21:18

Relative to radio astronomy though, it seems like with the influence Minkowski and Baade, that you became interested or you mutually--

Greenstein: 21:27

Yes, I certainly turned back to it. I retained an interest and much more sharply than it would appear because of a different thing. And that was the work on interstellar polarization and the almost certain requirements for an interstellar magnetic field which dates from the work by Leverett Davis and myself.

Sullivan: 21:50

Right. This was going on about the same early '50s, right?

Greenstein: 21:53

I think it started in '49.

Sullivan: 21:55

Right. And were you thinking all the time that this had something perhaps to do with the origin of these radio waves or was that only a later connection?

Greenstein: 22:07

Oh yes. No, that was to my mind almost obvious. Once one realized, and I had from listening essentially to Enrico Fermi, Fermi and Chandrasekhar tried to accelerate cosmic rays in space. Fermi liked an acceleration process involving interstellar magnetic fields and he liked also a magnetic field to keep the cosmic rays trapped in the Galaxy so that the total energy in the universe wouldn't be overpoweringly large in cosmic radiation. And so for both those things, he had at a different meeting, and I have no idea when that was, a very good lecture, essentially suggesting that the magnetic field energies were of the order of magnitude of the cosmic ray energy density in space, and that if there were fields in clouds, as clouds moved to each other, an electron trapped on a line of force connecting clouds would be accelerated and attempt to get into actually equilibrium in total energy with a moving cloud. Since a moving cloud may have 100 solar masses and a lot of magnetic field, the electron could get to very high energy. But of course, it then leaps off out of the acceleration mechanism long before. The other thing I believe, and I can't date it was that a man named Peters, a physicist, at Chicago, had been looking for the electron and positron component of the cosmic radiation. And at about this time began to establish reasonable probabilities that there were electrons so that Fermi's requirement of the field, the fact that there were cosmic ray electrons, at least possibly, although still, I think not certain, in the '49 period, made it pretty obvious that the observations of first, I guess, Al Hiltner and of John Hall in much greater detail, which produced evidence for an interstellar polarization rather than a stellar polarization, that this required a link. And it was an obvious link and that's how Leverett Davis and I, and how Spitzer, came automatically to the idea that cosmic rays indicating existing magnetic fields had to be connected with the origin of the interstellar polarization.

Sullivan: 25:04

Now, the link to the radio radiation, however, was not really made in the West, this [area?].

Greenstein: 25:09

No, it was not made. It was made in Germany, oddly enough, and sort of forgotten in the solar context of radiation of gyrating electrons above magnetic fields and sunspots. That's Kiepenheuer.

Sullivan: 25:24

Well, there were two very short little articles in Phys. Rev. in 1951 [2025 note: in 1950]  by Kiepenheuer and one by Alfvén and Herlofson, but they just died. I mean, no one did anything in the West. And what I'm referring to, of course, is that Shklovsky and Ginzburg and their associates just ran with the ball in the early 50s. Do you have any thoughts on why this was not thought viable or fruitful field by someone like Fermi or Chandresekhar or Spitzer or you, or?

Sullivan: 00:01

What is it? 13 January 1980. So in answer to that question,

Greenstein: 00:07

There were lapses on the part of the greatest of the people interested. Enrico Fermi quite clearly, mechanism in fact is not valid. Particles are not accelerated in space, but presumably in the cells of supernovae. But in any case, we didn't leap to the right conclusion, and a year later astronomical evidence came that there were in fact magnetic fields in our own galaxy and that they were pretty strong fields, in fact, of the same order of magnitude as Fermi had required for the origin of cosmic rays. And-

Sullivan: 00:46

This was Hiltner’s and Hall’s? work, you're talking about?

Greenstein: 00:48

Right. The observation which was done because Chandrasekhar had suggested that certain kinds of B stars of high temperature should have linearly polarized light produced by an anisotropy of the electron scattering scattered radiation. Hiltner looked for it and found it, but he found that the direction of the polarization was essentially the same in several hot B stars he looked at. And then he looked at more and he found more or less regularities and he found it in other than very hot B bars. Hall did a more precise observation and carried it over a good fraction of the sky. John Hall, who was then at the US Naval Observatory, way off his normal activities, had really the first mapping of the cell polarization. And the explanation of it, we felt, required the existence of a much stronger magnetic field really than one now imagines to exist, perhaps 10 times stronger. We being, in this case, Leverett Davis, a physicist at Caltech, and myself. And we published several papers including, I think, finally an enormous difficult thing in 1951, on the theory of interstellar polarization and its interpretation.

Sullivan: 02:31

Let me get back to the radio astronomy track. Can you tell me, once again not being able to interview Baade or Minkowski-- I'm sorry, I did talk to Minkowski, but it was of limited use. Can you tell me about their characters and what it was as you see it that got them interested in these radio sources?

Greenstein: 02:53

Well, the easiest thing to say about them, and I think it's fair, is that they were, for older people and they were not young when they started, the most open-minded, least bound by convention and conventional wisdom, and “everybody knows that,” and “it is generally assumed,” that I've ever met their [inaudible]. I think it's '58. Did I say it was '61 and Minkowski '58 in a crucial year of '51, '52 paper, or '52, '53 paper, or whatever? And yet they were like children. And part of this came from the fact that neither of them in their whole life had ever been bound by responsibilities for organizing anything. They could think and did think about science at their speed and with no interest or fear of competition in that way. Next, they were the major users of the 100-inch telescope during World War II. Baade was an enemy alien, limited in travel, but was allowed to go up Mount Wilson. The city was blacked out. And so the remarkable work he did, which resulted in the discovery of the so-called two major populations and the solution to the problem of the different Cepheids but break up of the log jam on the distance scale for the Hubble expansion all came because Baade was just an absolutely superb technician and used big telescopes when he needed to. They were the head of what was called-- I don't know which physically was called head, but they talked all the time, collaborated. They shared out the dark sky observing time. And both of them were quite conventional physics educated. Probably neither of them knew quantum mechanics, but none of this bothered them because they could look at what was in the sky. As people, they were just as warm and marvelous human beings as I can remember. One of the reasons I came to Caltech was to be near them. I had visited a year before, just for a month or so, and had such fun talking to them. And the tragedies are, of course, that they both knew very much more than they ever published. Baade kept absolutely no letter files, and Minkowski’s desk was a foot high with letters rotten from exposure to California air for 5 or 10 years. The claim was, and I think was partly true, that he knew where every letter was. They carried their correspondence out often in longhand. And the early, soon after retirement of Baade and his decision to return to Germany was a disaster because he took all his papers with him.

Sullivan: 06:14

And this was what time when he returned?

Greenstein: 06:16

Three or four years after that big paper.

Sullivan: 06:20

So that was '54 it was published?

Greenstein: 06:22

Yeah, ‘57 he went back to Germany.

Sullivan: 06:25

He took all those papers with him. And then what do you know about them?

Greenstein: 06:27

To my knowledge, Walter Baade wife, named [inaudible], was very jealous of him and his recognition and held onto them and a strong attempt whose outcome I don't know, was made by Jan Oort, who, living in the Netherlands, was not far from where the widowed Mrs. Baade lived. Jan wanted desperately for history and science to get those things. And I think it went negative. And I don't know what happened. And the only person who would know, I guess, is Oort, maybe van de Hulst would know what happened. But we discussed that in later visits when Oort, who also came to Pasadena, talked about it, and I don't know the outcome. They never came back here. Minkowski carrying things to Berkeley. And if anybody has any of Minkowski's paper or private handwritten notes from Walter Baade about this or that, it will be the Berkeley department.

Sullivan: 07:39

Well, I have gone through a lot of Minkowski's papers at Berkeley. They are there.

Greenstein: 07:44

Are there any letters from Baade? Are there any memos?

Sullivan: 07:47

Only a very few. It's mostly correspondence. Of course. I was looking only at the radio astronomy stuff with Mills and Bolton and that.

Greenstein: 07:57

Well, it's funny. Maybe they were so free because they had no responsibility. And historically, this has been a disaster because there are no papers.

Sullivan: 08:08

So what you're saying, it sounds like, is that their interest in radio astronomy was largely because simply they would go towards any new exciting things. It wasn't particularly that there were many other instances of such things.

Greenstein: 08:21

Yeah. Well, they had had a very fine, shall we say, a batting record ongoing for new things, one of which is supernovae. And in a certain sense, while we didn't really know, everybody had a feeling that, I can remember when we talked, and we talked incessantly on these topics at lunches and in the evening, socially, that they must have something to do with each other, that the violence of the supernovae must have something to do with radio bursts in the sun, which were known by then. But really trouble was Baade had everything in his head and in handwritten materials, and had a real constitutional aversion to writing papers. It comes from being a great observer technician with a very eclectic view of astronomy. He was a walking encyclopedia, in fact, about strange objects, about strange variables. And when he did this separation into the different populations, he had to know that there were certain kinds of long-period variables with periods from 100 to 150 days that had completely different space motion properties than the others. That group belonged to the halo. Then there were these strange so-called-- well, looked like double period Cepheids called W Virginus stars. And they too had different space motions. Well, there's a classical astronomy of space motions or something you would know. But that he had this kind of mind in which every fact about every kind of strange variable star was pigeonholed somewhere, and that this would somehow, when he resolved the nearby galaxies and the Local Group into the two populations, one with no very bright stars but with variables which belong to Population II out of the spiral arm--

Greenstein: 10:38

He knew all these things that would belong to the population. In fact, much of our lunch conversations didn't have anything to do with radio astronomy. Because did I know any other stars or any other properties of stars that were correlated with these population types? And Allan Sandage was one of the pioneers in noticing the extreme low methyl abundance in the Population II field stars, not in other galaxies. I think this freedom, which you can't imagine in contemporary science, to know everything, to read everything, and to remember it, which is genius, not freedom, and to put it together, was how radio astronomy could appeal to them. Most naturally, I think the direct impact was through the Crab Nebula, which is behind everything, it seems, in high-energy astrophysics. But--

Sullivan: 11:39

Well, now, the first that I know of them is in 1951 when Graham Smith gave them some very good positions of the bright radio sources. Do you specifically remember that they were thinking about radio astronomy in a serious sense before then, or?

Greenstein: 11:58

Yes, I would think they were thinking and talking of it from the time I got there.

Sullivan: 12:04

Right. But not actually doing any observation because you didn't know where to look, or?

Greenstein: 12:08

That's right. There wasn't much to do. I'm just briefly seeing [inaudible, sound of pages turning]. Baade and Minkowski, who have to be treated as a pair because of the lack of a record of what individually they did, were interested in anything new to which optical observations, and they were then the only observations and largely photographic, with large telescopes could make a contribution. And as I said, in spite of age, they were open-minded. The Crab Nebula had been an intriguing subject and I think Minkowski's first paper was 1942 on the Crab. It, unfortunately, had some theoretical errors in it. And so he and I collaborated on it. And by this time, photography had revealed that there were really two components. The so-called amorphous mass with a continuous spectrum, and that's what Minkowski had tried to explain, and which I tried to explain. And if one reads that paper, as I did recently, looked back at the paper on the spectra, the supernovae which Baade and Minkowski or I think they wrote separate papers and the paper together. But Minkowski had done the spectroscopic work. You can see that in a certain sense some of the problems of the supernova spectrum are even reflected in the way we redid the idea of the emission from the very hot plasma in the paper he and I wrote. And that paper, of course, was way off the ball, and since nobody had made the link to the synchrotron emissions, it was just wasted wind, in fact.

Sullivan: 14:12

Well, but you realized that, I mean, here in the abstract that the thermal emission is only about 1% of the observed radio flux.

Greenstein: 14:20

That's right. We couldn't do it. But Whipple and I couldn't do it in 1937, so we hadn't come very far. What counts is what succeeds, not why you fail. There's no point in explaining it away.

Sullivan: 14:34

Well, historians of science has somewhat different attitudes.

Greenstein: 14:37

There is another thing, by the way, that you have to know in between which is relevant to my lapse of memory. Because of the Korean War, I went into military research and I more or less vanished for a year and a half. And this was connected with what eventually sunk J. Robert Oppenheimer, a thing called Project Vista, which is on the arguments for nuclear atomic weapons for use in tactical situations and against strategic bombing. And I have here my humorous map of the great seal of Project Vista. cerbus victorius acadmia destructa militate disgustba], meaning--

Sullivan: 15:34

A loose translation.

Greenstein: 15:36

A loose translation, [victorious in ulcers the academy of the university is destroyed and is totally disgusted?] And it consists of a battleship, a missile, a machine gun, eye glasses - that's academic - bombs being dropped, and bottles with a fizzing glass near it representing what we did.

Sullivan: 16:02

I gather you were rather disgusted with the whole--

Greenstein: 16:05

Well, it was a very traumatic period. I was out for roughly a year full-time, and very heavily involved in it. It got me a certificate by Robert Lovett, Secretary of Defense, a personal letter from Mark Frank Pace, Secretary of the Army dated 1952. And so, in this critical year of '51, '52, I wasn't even at most of the lunches. On the other hand, I was still trying to be a scientist and run the department. So I don't honestly know the details, except this, that the radio astronomers did, in fact, turn to Baade, really, for photography of interesting fields.

Sullivan: 16:54

Right.

Greenstein: 16:55

And if Baade found anything strange, Rudolph did the spectroscopy, and nobody else, because, by this time, the completion of the 200 inch - it had really gone up the mountain in '48, but really wasn't used much till '51. The completion of the 200 instrument, of a special spectrograph for very faint objects, had made it possible for the two of them to do the best they could. So, if you wish, with a critical burst of new information when it was needed.

Sullivan: 17:33

Well, moving on with your connection with things, it looks like the next paper is indeed in 1954 about the energies of radio sources. It was one of the four papers in ApJ. And of course, by this time, you had the identification with the supernova remnants, you had the Cygnus A identification and Virgo A pinned down. So was the picture becoming a little clearer then?

Greenstein: 18:02

Yeah. And if one looks at it, except one has to look at it with a little knowledge of the giant correction to be applied. We were still using, as late as '54, the so-called old distance scale, the expansion of the universe, a la Hubble and Tolman 540 kilometers per second per Megaparsec, true value being nearly on the order of 60 or 70, I think now. We were still using it, but in all of those things, looking at the photograph, seeing the emitting volume, you found that even with the old distance scale, in which things were 10 times too close and therefore 100 times too faint, the volume emissivity, which is what we concentrated on, was just absolutely out of the question for anything that corresponded to unbelievable temperatures, we say so. And allowing for the fact that the things, if they're further away, also a bit larger, you don't lose that whole factor of 100. But there's a factor of 10, actually in the net. They're just much worse even than we knew. We didn't know where, let's say the radio source was in, say Virgo A. Was it in this tiny little thing, or was it in this giant elliptical galaxy? And so the consequence was that we put in too big a volume. Had we put in the correct thing that it was from a very small central source, or in, what is it? Centaurus A, where the strongest things are two tiny little lobes near the middle, within which there's an even tinier VLBI source. I mean, when you look at that now, you can just say, "Good Lord, how can you have been so conservative?" But we were talking down at what seemed to be rational limits and we just say as I remember it, that we just couldn't explain it. That we desperately needed another source of energy. And I can claim no credit because it hit us quite suddenly within-- just really before that was published, Hoyle had been here. Hoyle and Fowler had talked. I forget what date Burbidge gave the first things they wrote. You have to look that up. And we were just forgetting that people who had been talking to us had already told us that things were much worse than we thought. In the Manchester IAU, the radio astronomy symposium--

Sullivan: 20:50

In 1955, where you gave a review talk there, I wanted to ask you about that.

Greenstein: 20:55

Yeah, I'm still conservative. Let's forget, the whole thing was a bloody shame. Hoyle's visit in ‘53 interestingly enough, that I have it here, was a visiting professor. He covered formation of the heavy elements and collapsing stars at high temperatures, that's supernova, with theory formation of galaxies. No mention of radio sources yet. And yet that same year as I remember it.

Sullivan: 21:27

But Hanbury Brown came through that same time, so you certainly were getting a radio astronomer's contact [apparently?].

Greenstein: 21:34

Oh. The personal contacts because of these meetings, especially the one in Australia, gave us the link to the decision on what we were going to do with Caltech because by then we more or less decided that the subject was too important to be left either to failures of theory or to radio engineers. And so we thought, given the strong links that I forged with the physics group and nuclear astrophysics before Geoff Burbidge was born almost, in '50 or '51, I learned nuclear physics from Fowler and we worked together. We just decided that it didn't matter whether it was astronomy or physics or something, we had to do something. And we met all these guys

Sullivan: 22:25

You said the meeting in Australia. Are you talking about the URSI?

Greenstein: 22:27

Yeah, when was that?

Sullivan: 22:28

'52.

Greenstein: 22:29

'52.

Sullivan: 22:29

Did you go to that meeting?

Greenstein: 22:30

No, I didn't. But the people came through here. I tended not to go to--

Sullivan: 22:36

Well, I would have thought that very strange for you to be at an URSI meeting at that time.

Greenstein: 22:40

Well, oddly enough, I remember, I think at that time I was vice president of the IAU-- no, not yet. There was a discussion of where they should publish things and they were going to have their own journal. And either in the early period as counselor or later, I and others urged very strongly - and I think Chandrasekhar was quite favorably disposed - to the idea that the Astrophysical Journal should be the home for radio astronomy, and later that the IAU, rather than URSI, should be their official meeting place if we were going to bring them in.

Sullivan: 23:23

Right. Do you remember who was favoring a journal of radio astronomy?

Greenstein: 23:28

I thought that was mainly-- I thought that was either the Australians or the British. Certainly wasn't the Americans. They could publish in the Proceedings of the Institute of Radio & Electronic Engineers. But that was such an enormous thing. It would never have had any impact on optical astronomy.

Sullivan: 23:48

But the British were always publishing in Monthly Notices right from the very beginning.

Greenstein: 23:52

Well, I think there was a strong movement. I thought it was British, but it may have been Australian to create a journal for radio.

Sullivan: 24:01

I haven't heard about this.

Greenstein: 24:02

Yeah, there was. If it's mentioned anywhere officially, it would be in Dave Edge's book, and I'd have to look there. But I remember definitely a real concern that we would lose this topic. And whatever it was, it was part of astronomy. And certainly Chandrasekhar, I am absolutely certain, was quite excited and interested. Chandra was very critical of astronomers as being conservative, letting things sort of go by them. And he worked with distinguished physicists enough to know that great physicists were brighter than the best astronomers. But on the other hand, physicists didn't know how hard it is to get an astronomical fact straight.

Sullivan: 24:55

Right. Well, there was an editorial in ApJ around '56 or '57, emphasizing that radio astronomy papers are welcome.

Greenstein: 25:04

Right. Then that dates it, because then I was vice president of the AAS, and I'd left Yerkes, of course, as I had nothing to do with it, but I'm fairly sure the AAS had discussed this in the council meetings and so forth.

Sullivan: 25:21

Okay, let's go back to '54 in this meeting, which apparently you were part of the organization of, in Washington, DC. Can you tell me about that?

Greenstein: 25:30

Yeah, well. As I said, I felt that life was passing us by. We knew all these bright guys who kept coming and who kept writing letters to Minkowski after Baade retired, even. It wasn't so long. And there was internal discussion in the high administration of Caltech, which consisted of Lee DuBridge, ex-head of Radiation Lab, and Bob Bacher, head of physics, math, and astronomy under whom I worked about doing something serious in the way of radio astronomy. Now Caltech claims that it never does anything unless it does things well. That claim could be investigated by a historian. It might not come out that way, but that's the claim.

Sullivan: 26:39

That's the goal.

Greenstein: 26:40

There was this big argument whether astronomy should just swallow radio astronomy if it came. Next, if radio astronomy as a subject had a serious long-term future. If you remember that there was one line, the radio astronomy could observe a 21-centimeter line, a few years old. These discussions were, in fact, going on. Radio astronomy 21-centimeter line was an important addition to the arguments pro ,because a continuum all by itself isn't that much fun and you might exhaust it. And although the possibilities of interferometer for accurate location had suggested that you would have lots of sources if all you ever got was an energy distribution. And if you couldn't identify them all, which was, I think already the situation, you'd never get a distance to them. You wouldn't know what they were until you eventually got now one odd second or better resolution and pointing accuracy and there's only one stellar image from the ground per radio astronomy picture element. Well, we had quite serious discussions. I was then on a kind of just a nominal position. I was head of the astronomy option. There's a very queer organizational setup which we had to resolve. Research at Caltech and Carnegie using Mount Wilson and Palomar is done in the name of the Mount Wilson Palomar, now Hale Observatory. And radio astronomy didn't fit in automatically unless Hale Observatory accepted it. Ike Bowen, who had been a physicist and that by the forbidden lines very important in optics and astronomy, was not too happy about the idea of enlarging the wavelength range, mainly also because it meant such a new technology that the present staff, the staff they then had, might not have been all that suitable. And he was, perhaps, a little afraid of sort of diffusion about it. By the way, at that time, all work was privately supported by Caltech and Carnegie from endowment funds or non-endowment, in some cases, despite a capital. So a big expansion, a well-done expansion might have sort of outweighed the rest of the observatory. But on the other hand, we were quite free at Caltech to do whatever we liked if it weren't in Mount Wilson Palomar Observatory setup. So we had to work out an organization. So we put it in the physics department even for thinking. There was then a question for Bacher, the head of physics and astronomy, and me as head of astronomy, and DuBridge. And DuBridge had a personal strong enthusiasm for it because of his experience in the Radiation Lab. And also because fundamentally of the personal contact he had with E.G. Bowen, head of CSIRO in Australia, a protagonist of radio astronomy. Bowen was a frequent visitor. He was no longer a working scientist like Hanbury Brown or Graham Smith. Graham Smith, by the way, was visiting professor, I think the year after Hoyle. I don't have a list of all of them, but--

Sullivan: 30:45

I know that he spent a year at DTM, around '54 or so. And he came here to Caltech for a while at the same time.

Greenstein: 30:53

And maybe we shared them, and very likely that we shared the course then. And Peter Scheuer was another very early visitor. And in any case, we had radio astronomers as visitors. We had now this conclusively accepted theory, we're talking to '53, of the synchrotron source. And that put it at-- right in high-energy physics. We had Hoyle coming on a regular basis of three months, a year, I think beginning at '52, sometimes for astronomy, sometimes for physics, later, mostly the physics. And it just seemed a natural thing to do. But the interesting thing was that both Bacher and DuBridge wanted to be convinced, they really wanted to be convinced, that radio astronomy had a sort of infinite extension before they plunged in. So being rather people accustomed to power and organizational responsibility, they decided that we're going to have a meeting and discuss it, a national meeting. And Carnegie Institution of Washington, Caltech, and the Science Foundation, were essentially in an equal role, sponsored this meeting in Washington, which was held in the Carnegie Institution headquarters in downtown Washington.

Sullivan: 32:29

And I believe that was January '54.

Greenstein: 32:31

January '54. And I was head of the organizing committee and wrote--

Sullivan: 32:38

This meeting, though, was to look at the whole US role in radio astronomy.

Greenstein: 32:43

It's worldwide. If you've never seen the program, it's fairly impressive.

Sullivan: 32:48

But no, it covered the whole development. But was not the goal of it to say, “Alright now? What does the US do?”

Greenstein: 32:55

Yeah. Exactly. Right. Right. There are two aspects of that. Should Caltech do it? Should the National Science Foundation think of something big in radio astronomy? And the resume, I guess, is here, December 31st '53. “Some 75 leading astronomers, radio astronomers, physicists, and electronics engineers have been invited to the conference from the United States, Canada, Australia, England, Netherlands. Among them is Professor H.C. Van de Hulst,” who would come to Caltech as visiting professor in astrophysics after the conference. Among the speakers from here were Lester Field, who became a vice president of Hughes Aircraft, now retired, Rudolph Minkowski, DuBridge, and myself.

Sullivan: 33:54

So what happened at this meeting? What do you see-- the role of this meeting in the development of radio astronomy?

Greenstein: 34:00

I view it as sort of seminal, but that's just because-- I found it really-- one of the really good meetings that we've ever had. I don't like meetings, actually.

Sullivan: 34:14

Why was it good? I mean, what was it about the meeting that--?

Greenstein: 34:18

I'd say it represented the over the world, reports on the culmination of the world of the World War II, an immediate postwar growth of radio astronomy, and it was really exciting. By the way, I mentioned before that Merle Tuve had wanted radio astronomy in Washington at Carnegie. It would have been a natural thing rather than here in the Mount Wilson-Palomar observatories. Incidentally, Charlie Seeger was acting assistant director for math, physics, and engineering sciences in the NSF for that year.

Sullivan: 35:06

At NSF? I see.

Greenstein: 35:07

Yeah. And so we were talking as much to each other, listening to the people from outside, and as we were talking to the NSF with the idea that there would be some funding started.

Sullivan: 35:27

Well, if it had-- of course, this is seminal for the growth of what became the NRAO, also.

Greenstein: 35:32

Yes, yeah. That was--

Sullivan: 35:34

But was there not a possible conflict that a decision would be made there that, all right, NSF money should go to a national observatory, and then you at Caltech would be left to your own.

Greenstein: 35:48

Shall we say that that is a long story. Sure, sure. You can't have everything. If you're going to ask for-- if you're going to ask for government money, you're not going to retain your freedom. On the other hand, if you're in on the ground floor, you at least have a fighting chance, and all of this led to terrible conflicts later about who would operate the national radio observatory. But at least I view it as seminal in that even if it led to the conflicts, the conflicts eventually led to NRAO, which was outstanding success in government supported research, in my opinion. One of the outstanding successes. I view the National Accelerator Lab and the VLA as really great things. They really make a difference. So nobody knew who was going to ride the tiger, but we better at least get the tiger rolling. And I thought it was a great group because it is, in fact, a worldwide representation, except for the Russians, and I don't even remember whether we tried to get them, but I noticed, this is my working sheet—Alfven was added. [inaudible] didn't come. Van Atta, he was-- people that I had really just met. Charlie Townes was then at Bell Telephone.

Sullivan: 37:31

Right. I think he talked about possibilities of molecular spectroscopy, yeah.

Greenstein: 37:35

That was really, to me, the high point, incidentally.

Sullivan: 37:39

An amazing paper, right?

Greenstein: 37:40

Yeah.

Sullivan: 37:41

I'm still a little puzzled. Were you thinking, then, that NSF might want to go for a national observatory, but then that Caltech might be able to operate this for other people?

Greenstein: 37:51

I have no idea whether-- no, not Caltech. In any case, it would have been-- no, we were certainly thinking of our own radio observatory at or near Caltech, with our own astronomy staff closely linked to it. The Carnegie Institution was thinking of it as possibly something near them - remember, that's a sponsorship - because they wanted to expand, and whether they would have done it with government money or not only came up later when Merle Tuve of Carnegie tried essentially to create an organization of half a dozen universities rather than let it go to AUI. Among the conferees was Wiesner, who was one of the greatest science politicians. And it was interested in the ionosphere, and fighting with him was a problem. And the other name I'm looking for is the man who was head of AUI, who in fact eventually won the battle for power.

Sullivan: 38:59

Emberson?

Greenstein: 39:00

No, he was just an employee. But there was a distinguished electrical engineer, physicist. [Note added 2025: Lloyd Berkner]

Sullivan: 39:07

I know what you mean. I can't think of it.

Greenstein: 39:08

Yeah, he's dead. He died.

Sullivan: 39:10

Anyway. You're saying that he came into the ascendancy and that's why NRAO came under the auspices of AUI?

Greenstein: 39:14

AUI. Exactly. But we had everybody who was anybody at the meeting.

Sullivan: 39:24

So you were not directly involved then in the development of NRAO, although obviously, I'm very interested--

Greenstein: 39:29

Well, I had six or seven hats from 1952 to, I think, 1956 or seven. I was on, or chairman of the Advisory Panel for Astronomy for the NSF.

Sullivan: 39:47

I see.

Greenstein: 39:48

I was pushing there and I was pushing else on the outside. '49 to '52, chairman of Astronomy Advisor panel ONR, NBS, and then '53 to '57 was-- but I think I was actually in '52 already. The first year on the committee of Consultant on Astronomy and Radio astronomy to the NSF and the Mathematical and Physical and Engineering Sciences Divisional committee to the NSF in '60. So I was an NSF advisor from the year it was formed in a tiny committee which Bob McMath of Michigan started with Leo Goldberg, Martin Schwarzschild, and myself, and Whitford, I think it was. Before there was any budget. I think they had $200,000. They had an astronomy committee. And that's in a sense, one of the reasons astronomy bulked so large in capital funding was that we were really in on the ground floor. McMath was a friend of the head of the Bureau of the Budget and sort of begged him to make sure that if there was any money for NSF except for the director and his few assistants, that would be an astronomy committee.

Greenstein: 41:13

So the fight was not always pleasant, and I wore too many hats. I wanted it here. I didn't want a national observatory. I wanted a good radio observatory in a university setting. The future of radio observatories in university settings is extremely dim now.

Sullivan: 41:35

Well, this is 20 years later.

Greenstein: 41:38

20 years later, NRAO--

Sullivan: 41:40

Was it a philosophical objection to a national observatory that you felt that it wouldn't have the excellence, or that it would get too big and too unwieldy? Or what was it about it that did not appeal to you?

Greenstein: 41:54

Shall we say I'll write a book about it someday, if I can remember it? No, that is too big a question, really. It's clear that you're never going to spend an enormous fraction of the federal budget for basic research on astronomy unless you give up some degree of control. I think philosophically and practically my whole life in astronomy had been at centers of excellence. At Harvard, when I think it had invented astrophysics in the 30s, and applied it to the stars rather than just mathematical fiction. Yerkes at I think its best. And then, Caltech, I hope at its best. And the observatories is here. All of them privately supported, all of them believing almost in the principles of Baade and Minkowski. Follow your nose where it wants to. And although I was a government advisor for a year, there was the first government committee in astronomy, the ONR thing, and it had $80,000 to spend a year. I'd always felt that the universities were where good science could be done. And there was something deadly in government labs.

Greenstein: 43:30

And I must remind you of one thing. After World War II, there were many government laboratories, but they were in a state of complete crumbling. Anybody good who had been there had left when the War ended. Had done their duty, and off they went. And this is a very rough period for government laboratories and merit in government-sponsored research. I was an advisor also for example, in the same period, to the US Air Force. Scientific Advisory Board of the US Air Force, and they were sponsoring research. And it may still be classified, but I can assure you, it wasn't any good. And the Army was the worst of all. It had [inaudible] or something in Texas. It was a place where the Army radar was supposed to be. It was a disaster area. I'm sure all of that's libelous. And in fact, there was no real proof that the government could do what it now does, give the power and give a regular budget. And in the fact, of course, the case still remains to be proved because it doesn't give a regular budget.

Sullivan: 00:01

This is continuing with Jesse Greenstein on 13th January 1980. So therefore you were trying to get it into Caltech, but was this in essence, competing for the same money, because of course, I know that you did get an observatory Caltech, what was the source of money for that?

Greenstein: 00:21

It was in fact, the Science Foundation, though we were not so convinced in the early days that, for example, Carnegie, which was pretty big, couldn't have gotten some more capital and put it into radio astronomy. It had had radio astronomy, Howard Tatel worked there. And when I broached the subject of this meeting in 53, 54—to Merle Tuve, who I had not met, it happened, until I brought up the topic. I think he was one of the organizing committee with DuBridge, myself, and John Hagen. I said, "We're meeting because Lee wants to find out whether radio astronomy is here to stay," And this, I believe, is a verbatim quotation from Merle Tuve, who's a very good scientist. He said, "Jesse, how can a young fellow like you be such a conservative son of a bitch?" That's true. I didn't particularly think we needed the meeting, I knew, but it was an extremely good meeting and one that excited me when it happened. While I went to Manchester the year after, I thought that was really from dullsville.

Sullivan: 01:41

Relative to this meeting?

Greenstein: 01:42

Yeah, because this was a good meeting. And Lee came away completely convinced on Caltech's future role. And I remember-- and I wish I remember who was at it I remember a small room with maybe half a dozen people. And it must have been Charlie Seeger because the NSF was involved. We discussed the idea of a national radio observatory.

Sullivan: 02:09

At the time of this meeting?

Greenstein: 02:10

Yes. The day it ended. That's not naturally in any of the press releases of it, but everybody who eventually counted in the growth of NRAO was present. I think Bob Dicke was one of them, Bart Bok almost certainly. The guys who pressed for it were at this little private get together, the burden of which was to tell the NSF, more or less-- I don't think we passed a resolution and it wouldn't have done any good, they didn't have money-- that this was going to be a major thing for them to do.

Sullivan: 03:00

And of course, they did fund Bok just about that time.

Greenstein: 03:03

Yeah, but that's another small private thing and Michigan was going about that time.

Sullivan: 03:11

So tell me about Caltech now. So you came back and now you have the mandates, more or less, and DuBridge was convinced, so how did you proceed to get a radio group going here?

Greenstein: 03:22

Well, I had two choices in mind. We had nobody I felt in the United States as quite the quality of the Australians and Brits. I had met Hanbury Brown when he was doing this experiment in the lab on the quantum nature, and the fact that you could get this kind of interferometer work. It was just a thing set up not far from the main lab of the Manchester Radio Group. I'd seen that. I forget what year, but it impressed me. And of course, physicists then, would find this impressive because they believe that light arrived in quantum, but that it [inaudible] show it. And the other person was John Bolton. And John, I think, probably felt more like moving. And Hanbury was a little committed already to the completion of his type of interferometer. And he felt that it might have an enormous impact on optical astronomy. And I think he felt obligated.

Greenstein: 04:42

I had spoken to both of them, at least as potential heads. And I really did think a lot about the United States situation. But these people were different. And they were really mega scientists. And Haddock was a very good man. He wasn't terribly deep. And John had been so successful in the sources. And E. G. Bowen was also a strong protagonist of John Hagen, of John - not Hagen - Bolton, to DuBridge, which was all to the good. And so, we asked John if he would come. And he would come as director and senior research associate or fellow or whatever it was called in physics and astronomy and radio astronomy. And the whole organization and all the funding and so forth was to be carried out in the divisional structure, which was Bacher.

Sullivan: 05:46

Outside of the department.

Greenstein: 05:48

Well, it wasn't my building. And the people eventually became-- those who did stay became professors in radio astronomy, which is astronomy. But we have a very loose structure. And half of astronomy, in fact, is done by professors of physics, although, say, Marshall Cohen and Moffett are professors of radio astronomy. But they were not in optical astronomy, was the point. So, that thing we were committed to. And we were either going to raise private money or get government money. But whatever it was, it was going to be separate from Mount Wilson Palomar. And Bowen worked out a convenient definition, that is, optical astronomy went up to one millimeter. And since radio astronomy was nowhere near there yet, that was okay.

Sullivan: 06:41

Right. No conflicts on the other side there.

Greenstein: 06:43

That's right. No conflicts yet. It turns out [that there were?]. But it was fun. And I was relatively younger and flexible. And in spite of all this government garbage I was doing, I was pretty much involved in raising the money, which was DuBridge going to the NSF, certainly. And I think the Institute put in a considerable private capital just out of its own funds to get John Bolton started with something to do. And the only thing we could do until we got something big was a 30 foot or thereabouts, 21-centimeter thing, which was up on Palomar, and which was operated for some years, and where John Bolton demonstrated to me that you could call up generals in command of Marine bases, in this case, and tell them what their radar was doing wrong and scare the hell out of them. That literally happened. He was picking up interference for wandering radar. And he just told them everything about their apparatus. So they turned it off and cured the frequency error, and then wanted to know what John Bolton was up to. I think I told a security officer on the telephone that he had been involved in developing Australian  radar and worked with the Navy and the submarines in the South Pacific and that satisfied him. He was okay.

Sullivan: 08:25

Now, I have talked with Bolton and so I have his point of view on these developments of Palomar.

Greenstein: 08:30

Did he mention who first asked him to come?

Sullivan: 08:35

I don't remember. He may have.

Greenstein: 08:36

There's some concern. Maarten Schmidt asked me whether, in fact, on one of these visits, Baade and Minkowski didn't short circuit the whole loop that I'm telling you about by asking him whether he would come.

Sullivan: 08:51

I see.

Greenstein: 08:53

Because that's what they could do, because they had absolutely no power and no authority and no money, but had everybody's attention. I don't know, I was curious.

Sullivan: 09:04

He may have, I don't remember.

Greenstein: 09:07

Certainly Taffy Bowen's recommendation was important.

Sullivan: 09:12

So you had to [scout up?] the money, you didn't have it when he actually came.

Greenstein: 09:19

I think nothing.

Sullivan: 09:21

And I suppose that Bolton had to put together exactly what he wanted and how much money he wanted to--

Greenstein: 09:27

I would guess for that 21-cm this thing it couldn't have been money.

Sullivan: 09:31

No, but I mean for the interferometer.

Greenstein: 09:34

Oh, yeah. And what happened was that whatever organizational structure we had, Caltech is a small place. And the advantage was that although DuBridge was interested, he wasn't going to be in on daily operation, but he would carry the ball, i.e. the proposal to a friend in Washington, but Bob Bacher, who was with I worked, directly, was the sort of responsible administrator above Bolton, the director of the radio territory. And he would say, look at these budgets, see how they fit it in with Caltech policy. What were we doing? We were hiring enormous number of post docs or even free postdocs who are going to get their degree as research fellows and what was our obligation? That's sort of a worrisome thing in a small place which suddenly gets a lot of government money. And that money escalated rather fast, I mean, for us. It was comparable to the Palomar budget, I would say, almost immediately, when there was something, when they got the interferometer, and they must have had a bigger staff than the total support staff included for Palomar. So we ran away in dollars, but on the other hand, since it was largely NSF money, and some ONR, I think we had both for a while.

Sullivan: 11:10

Right.

Greenstein: 11:11

Oh, [inaudible]. That was the secret.

Sullivan: 11:15

It's all right.

Greenstein: 11:16

We were not going to the NSF right away. We went to ONR. And ONR, I even know the man's name. ONR felt that radio astronomy was important and directly applicable to its mission. And the first money that we got came through an ONR office here in Pasadena, which is responsible for Inyokern etc., which was a Navy operation, China Lake and so on. And out of that budget and package they supplemented, the first monies, plus private money to operate John Bolton's thing, were available. And then the ONR built up quite a large level there. In fact, given the value of the dollar, probably much more than the NSF now puts in, because it was a construction going on. So we were very lucky in having the right friends in the right place and we did not in fact compete at any time early. And I'm glad you brought this up. You asked me were we going to compete with the future NRAO which was being pushed with the Dicke committees and so forth [Note added 2025: NRAO and Caltech did compete at the Dicke Committees in the 1960s for NSF funds to build a large array]. And the answer was no. We were in ONR rather than in NSF and we are now a dropout in NSF like Michigan, so forth.

Greenstein: 12:44

They closed down various places and this money became unavailable. But I want to again remind you that my superiors and John's superiors were people who had always worked with the Department of Defense. And for them getting money, if you didn't get in one place, you got it in another. The most important person in ONR who was strongly interested when it got expensive was a man named Admiral Chuck or Chick Hayward who was an operations officer in the Navy, went to Caltech during World War II, had been instrumental in perfecting torpedoes.

Sullivan: 13:32

I see. So he was in favor of--

Greenstein: 13:35

He knew these people, they were good Joes, and he knew that research paid off. ONR had, for my whole life as an advisor to the government, the highest brownie points on taking a broad view of its mission.

Sullivan: 13:52

Well, the record shows that over and over again.

Greenstein: 13:56

And it was-- I mean, whenever anybody from ONR wanted anything, I would do it. It took me to this Project Vista which left me in the Air Force thing years before I asked the Air Force for a dime for research. It was '57 before I got any money from the government for my own work.

Sullivan: 14:18

And would you agree that the Naval Research Lab is the best of the military research labs in terms of basic science [crosstalk]?

Greenstein: 14:28

Well, I mean it's beginning to have problems because things are too expensive. But it had the rocket program for X-ray astronomy--

Sullivan: 14:36

Not just astronomy. I was thinking [crosstalk].

Greenstein: 14:38

In a broad way, sure.

Sullivan: 14:39

Including [inaudible].

Greenstein: 14:41

I had a rocket shot in 1947 on a V2 to get the spectrum of the sun and it failed. That was supported via - what was it? - a tax thing in Silver Spring, Maryland.

Sullivan: 14:55

Oh yes, [inaudible].

Greenstein: 14:57

One of those things. And so I mean we'd always had good contacts and good relations and maybe when you asked me was there any devious politics in this conference with the NSF and future NRAO, I would say no, really, because we were off on this other thing and maybe DuBridge had had already a talk with Taffy Bowen. Not more than a few years later, Bowen was trying to build an incredible, enormous radio antenna in Australia. I don't know if you’ve ever seen pictures of the idea or the model of floatation.

Sullivan: 15:39

Yes, yes. Well, this was one of the models considered for the Giant Radio Telescope they called it, that eventually, of course, became the 210 foot at Parkes.

Greenstein: 15:48

Yeah, well, he was trying to sell out in this country, thinking that DuBridge, an old friend, would dig up some money for him. And in the long run, he did.

Sullivan: 15:58

Sure. And the Ford Foundation funded--

Greenstein: 16:00

Grant. That's right through with DuBridge’s help. And that's when they stole John Bolton from me. And at this point is where I got mad. But that's a sad story and much later. But we were really able, since we were so small, and had the two senior administrators just right with us. And I say it was the '54 conference, which sold not only us, but I think the NSF, about the quality of the science that could be done.

Sullivan: 16:30

Let’s see- Bolton went back in '62 or so?

Greenstein: 16:33

Yes, much later.

Sullivan: 16:34

Right. But I want to ask, over that whole period, he came in '55, I think?

Greenstein: 16:38

Yeah, roughly. '55, I guess you're right. We went to the Manchester meeting together, he and I, and we drove around Scotland for ten days or something after the meeting, I bought a new MG. And in fact he already accepted to come and [inaudible], so I know that whatever. I don't remember, I don't have all dates here, but we're sort of clear that we were doing a good job and getting him. And he brought Gordon Stanley, who has been practical. And then we immediately began inviting all the people we could as visiting professors, even if they weren't going to stay.

Sullivan: 17:23

But I wanted to ask, over this seven-year period that Bolton was here, were you and was Caltech basically pleased at the progress of what became Owens Valley and so forth?

Sullivan: 17:34

Oh, yes, delighted. All right. The answer is clearly yes. We had the following sort of-- in fact, I see I am reporting even in my annual report on radio astronomy--

Sullivan: 18:01

To the AAS.

Greenstein: 18:02

No, this is to the president or something in this period.

Sullivan: 18:17

I think it is fair to say, though, that there were very few solid radio astronomical results that came out of Caltech until '60, '61 in the Moffet-Maltby era, when you began to get all these doubles and this kind of thing.

Greenstein: 18:37

You mean how fast should we have succeeded?

Sullivan: 18:41

Yeah, that's a five-year period. And what you're saying is that's sort of what you expected?

Greenstein: 18:47

Well, 21 centimeter was, to be honest, didn't amount to much, and there were other places that were doing it better. Radio source identification had to wait for the interferometer and the shapes and sizes, quite clearly. And there, I'm afraid, whether we were slow or not, I can't go back that far in my mind. I thought we started well. And there's one other thing. We got a couple of optical astronomers into the radio astronomy setup. It was being paid for by ONR. But Tom Matthews, for example.

Sullivan: 19:31

Tom Matthews. This is now getting to '60, '61.

Greenstein: 19:34

Well, no. But when did he come? He came--

Sullivan: 19:36

I'm not sure.

Greenstein: 19:38

The point was his triumphant period was with-- we got Maarten Schmidt as an optical astronomer, and we got Tom, who worked on radio source identifications. And Baade and Minkowski were gone. And he did it, unfortunately, he was a non-publisher. I think, you know, around Maryland, is still a non-publisher. I'm not criticizing him because he was a fine fellow. He had his own reasons for his problems. I was happy with the--

Sullivan: 20:10

Anyway, they were brought in as an integral part of the Radio Observatory

Greenstein: 20:14

Radio Observatory. That was a little bit off the agreement, but it didn't really matter too much because Mt. Wilson, the Carnegie side, had lost their great identifiers and Allan Sandage had worked on it. And I think he had gotten a bit turned off by the lack of interesting identification after those first few, he identified things, but they weren't important and breakthrough.

Sullivan: 20:44

Did Schmidt come first on ONR money, are you saying?

Greenstein: 20:46

No, Schmidt came first as a--

Sullivan: 20:49

Carnegie fellow.

Greenstein: 20:51

As a Carnegie fellow and worked on the subject which he published nothing about. But he taught a great deal, and I had met him much earlier in connection with some meeting where he had developed 21 centimeter model of the galaxy. But he wanted to do something, I think, about clusters as spiral arm traces, and that had been a flop. It was photoelectric diagrams, and they hadn't got much out of the visit. But Baade and Minkowski have completely sold on him. And there is really where Maarten is really addressed. He wants to know who the devil pushed him for here. And with Baade and Minkowski and me in all our conversations, I haven't the vaguest idea whether it was Baade or Rudolph who said, 'We got to get Schmidt on the staff." And I said, "But he's a Carnegie fellow and he’s working on the wrong thing." I don't think it's clear, my memory doesn't count here. But we want him. Or I wanted him desperately at Caltech to do radio astronomy on the optical side because the people they had coming through the Radio Observatory, postdocs, were not necessarily the best. But we had some pretty good successes. And I want to also point out that they were really building something and building it on the cheap. And that distinguished R. Wilson, half Nobel Prize, earned distinction as a physics graduate student as, however, a bulldozer driver, because he did the leveling for the track. He had the practice at home.

Sullivan: 22:47

Well, all of the students in that era have stories about laying cable and operating bulldozers and so on, this was the Bolton philosophy approach.

Greenstein: 22:55

Yeah. I don't think it was slow. I'm impatient as a person. I think it was going along about as fast as it could. I'm not going to justify that. I just felt happy and know that we were building as fast as we could. And the kids were so loyal to John Bolton. And John was such a magical person; charismatic is the contemporary word. These people are just linked to him; I think mostly fond of him. If there are people who are not, I'd like to mention that off camera. But I just found him the right thing. His secretary was Owen Wilson's wife, was just terribly fond of him for a generation. They all worked 20 hours a day. It was a great period. And finding these shapes and sizes and positions of the sources was important. And Maarten Schmidt's early work on radio galaxies depended on that, you see. And it was he who found that really even the "normal", quotes normal, but not the non-very-- the not-very-intense radio sources. He found that they were all emission line objects, and that they were-- and then Bill Morgan came and actually worked downstairs with the radio astronomers on their visit. He was some kind of - I don't know what - say, the visiting professor. But all his work was on the 48-inch Schmidt plate with Tom Matthews, I think, really is almost the key here. And Bill Morgan was a visiting professor. I know that.

Sullivan: 24:48

That's right. It's now coming back to me. Matthews, Morgan, and Schmidt was the paper that came out.

Greenstein: 24:52

Yeah. I mean, the cDs on the giant galaxies and clusters, and the recognition that often you had these-- when the doubles were found, you had these things very far apart. I think 3C 66 was the baffling one with the bright sort of-- looked almost like a collision of the galaxy with a cD or something. They're way off on one side.

Sullivan: 25:18

Right. And of course, you have signals from several years before. Let me ask you now about-- this is sort of the last topic. The very earliest radio source identifications with these stellar objects, you were involved with 3C 48, I believe it was.

Greenstein: 25:39

Yeah. Just a minute. Can we hold it one second? I just found another interesting point.

Sullivan: 25:44

Okay.

Greenstein: 25:46

You asked me how come we didn't get synchrotron. In 1956, there is a news release, "Walter Baade has found polarization by photography confirmed by Bill Baum and Fritz Zwicky." And also M87, and being the Crab. And now “Greenstein says, ‘One of the two possible sources of electrons that accelerated the synchrotron action and may cause the light emissions in the Crab Nebula,’ says Doctor Greenstein.  ‘One is the spontaneous breakup of subatomic mesons produced by nuclear reactions. The second is thermonuclear fusion reaction, both completely wrong. This discovery of polarization in the Crab Nebula also initiates speculation concerning the origin of cosmic rays.’” Took me a whole long time. I at last got there.

Sullivan: 26:42

Right. This was when they got the polarization in the jet of M87?

Greenstein: 26:45

Yeah, yeah. That was it. Now we go back to--

Sullivan: 26:51

To 1960, I believe is it. Not 3C 48 in which you played a role?

Greenstein: 26:58

Well, the quasar story is in an awful lot of print, but I'll try, well--

Sullivan: 27:05

Just your part of it.

Greenstein: 27:07

Well, my part was the following. The compact point-like quasars, now called sources, had a very sad and odd history in identification. The first spectrum taken of a quasar I took in 1960--

Sullivan: 27:37

Of which?

Greenstein: 27:38

--and I didn't know it was radio quiet.

Sullivan: 27:42

Oh, I see. [laughter]

Greenstein: 27:43

It's a QSO. It was an accident. It was supposed to be a white dwarf.

Sullivan: 27:49

I see.

Greenstein: 27:51

And in 1960, I took spectrum, it's Tonantzintla 202. And it is in the paper by Eggen and myself the first list of white dwarfs that Eggen and I published in '65. And there's a lot of notations about it in there. It says possible old nova, supernova. You couldn't identify the lines.

Sullivan: 28:16

Right.

Greenstein: 28:17

It had weak possible emission unidentifiable. And it's dated 1960. And so eventually, when we got lists of white dwarfs together four years later and the paper came out in '65, it was stuck in. It is the largest error in distance in history because it's a white dwarf, either at 20 parsecs, which was white dwarf, or  it's a quasar at 37% redshift, which I found later, that's much later. So the first I took by accident and didn't recognize. Then Sandage got a couple of these point objects that he and Tom had gotten the weird colors for.

Sullivan: 28:58

3C 286 I think was, I don't know [inaudible].

Greenstein: 29:00

There's quite a list. It's the paper they published. I think there are five or six of them there and not 273, not 48. And then 48 is added in a note to that. And what happened was that in those days Sandage would be at these lunches with Baade, Minkowski, myself, and maybe Schmidt at Caltech. And we just got to be a joke. Everybody got one of these things. Allan took 3C 48 and he gave up on his head. It's another one of these, like, "What is it?" We cannot recognize any of the lines. Some of them have pretty good lines, pretty strong. Others have pretty weak lines. Two of two atoms have very radical weak lines, just marginally visible. And 48 had this disaster of having a line which there is right at the absolute ultraviolet cut off, switches around 3,150 or so. So it's 3,150 divided by 137-- I'll look.

Sullivan: 30:29

He's now pulling out that antiquated instrument, a slide rule. I haven't seen one of those in a few years.

Greenstein: 30:36

That's quite right. Isn’ t that correct.

Sullivan: 30:38

But it still works.

Greenstein: 30:41

[inaudible] It couldn't have been 1909, but one of those lines that just made it from the ultraviolet to the absolute end of the spectrum. And you didn't quite have to believe it. So Allan said, oh, it has a couple of lines and I don't know what they are. Jesse, you take it. So I took three or four spectra of 48 with the prime focus spectrograph, which is what Minkowski and Allan Sandage had used and I used. I then had broken into the dark time observing for the white dwarfs, and we had just this ridiculous charade after an observing run. Maarten had observed some one of these, I had observed, I think Allan Sandage had stopped observing out of sheer disgust, having given me 3C 48 specifically to work on because it was one of the brightest. And we would talk to each other at lunch and, I don't know lines here, here and here, and every time they're in different places. It was a ritual. Then, I think we even had a bet that someday we find a line at the same place. But never, not once in this time. There were all objects had enough different redshift to prove so that none of them were in the right place. No two could agree.

Sullivan: 32:19

But what was your attitude? Did you really see this as a fundamental problem that really had to get solved, that this could be a big breakthrough?

Greenstein: 32:26

Oh, yeah. Well, the trouble was, since most astronomers in those days believed that the universe was rational, we tended to hope that some of this stuff would eventually make sense. And we had these funny conversations, which were the humorous ones. The ones about radio galaxies were great. Maarten has got a new one at a pretty good redshift. And we talked about the physical conditions. We knew by then that the high-density gas is sometimes pressed 3727. So that in a sense, Minkowski had been incredibly lucky in getting 3C 295 at that big redshift with only 3727.

Sullivan: 33:23

But that story was making sense in the radio.

Greenstein: 33:25

Radios were making sense, but the point sources were not. Clear evidence then and this comes again from the sense that we had had that the supernova had a lot to do with the radio sources in general. Minkowski had a spectrum of, I guess one of the filaments in the Crab, which was particularly high excitation, it doesn't have hydrogen. It had helium 2, quite strong. I believe that was the one. Or maybe one of the Cas A filaments, except they have hydrogen. And you'd say, well, what these things have got to be are old supernova remnants. That was sort of the thing that led us for quite a while in the wrong direction. That the lines are different because every one of these supernovae is a different age and you've got different unstable radioactive elements. And I ended up writing a paper, which I actually gave at a meeting, I guess, in Goddard in New York on the interpretation of 3C 48 as an elderly supernova remnant, because its lines happen to sit at observed wavelengths in our frame corresponding to a very strong emission line of oxygen 6 which is common in planetary nebula nuclei and stationary helium 2 at 4686 and 8835 [inaudible].

Greenstein: 35:13

And I even computed how many dead supernovae remnants, which we would now call pulsars, there would be near us, and just had, in fact even a nuclear reaction chain of modified light element or process which would explain many of the lines. And you just have to say that the reason they're all different is that some are 1,000 years old and some are 10,000 years old. We knew what the Crab looked like and so we had to make it older, 10,000 and 100,000. I knew so much nuclear physics that I also knew that, I don't know if you know this, but if you have a mixture of enormous number of radioactive unstable elements from a nuclear explosion, fission, and so forth, you find that the activity goes down not exponentially but inversely as the lifetime of age. Because what happens is as a rapid decay nucleus dies, a slower one takes over and it's a hyperbola.

Sullivan: 36:25

So the assemblage as a whole.

Greenstein: 36:26

The assemblage then would have a one over age.

Sullivan: 36:30

I see. So that would make these things last longer.

Greenstein: 36:32

And the luminosity would then give it to you by this time. I had this incredible paper in my files which was never published. It was all ready and it was given and Maarten found 3C 273.

Sullivan: 36:45

Before you had sent it off. [inaudible].[Note added 2005: Actually Greenstein had submitted his paper and then withdrew it when he and Schmidt realized that the redshift of 3C 48 was 0.37]

Greenstein: 36:47

Yeah, I didn’t present it, I think it was December.

Sullivan: 36:50

Maarten Schmidt has told me about his discovery story. And one aspect of this is that after he had convinced himself with 15 or 20 minutes of playing around, he went down to your office. So what did you think when he said--

Greenstein: 37:10

He said Jesse, I want to show you something. He's cute, but he seemed touched so this is a little odd. I already had something. He went up and showed me this little thing and there was hydrogen in the wrong place. See, all the action, 2,800 in the wrong place, Neon 5 in the wrong place, lines from the near UV or the unobservable UV. And here is this thing with a small enough redshift so that the only wrong line is in fact the magnesium 2 line, 2,800, which had just peaked into the ultraviolet end which reminded me of 48. Now, the funny thing is, I swear, and I think it's correct though, Iremember -  I’ve told the story so many times, but the first thing we did was look at this and I said, 37%. He said, no, 16%. He said, no, 37%. That's 3C 48. Because it turns out, Bolton, Matthews, and I had discussed a coincidence that you could explain 3C 48 with a redshift.

Sullivan: 38:24

I see.

Greenstein: 38:26

Bolton says he did it first. He's quite nasty about Tom and I publishing it. I give credit to my psychology, call it preconscious, and to Tom, so that's why we published it together. Afterwards, I got Tom and we did it. But the interesting thing is that my and Maarten's further activity was not about 3C 48, which was immediately explained then, but to explain away this thing. It didn't have to be hydrogen. It could be a hydrogenic atom with a different principal quantum number than two and a different charge on the nucleus. It could have been boron-8, or not boron-8, whatever it is, six times ionization. You actually can get a hydrogenic series, like helium-2 has an extra series ending at 80, not 8200, it’s 6700, and one that you never think of.

Sullivan: 39:38

Yep, yep.

Greenstein: 39:40

And so we played with the slide rule and Z and N principle quantum number till it was absolutely convincing that it wasn't going to work out. It had to be-- I forget what we found something that would do it, like oxygen seven times ionized. I think maybe we would have done it with a principal quantum number and then six or something like that. But that's so ridiculous. Had it been, let's say, helium, but we knew that it wasn't, because we know where the helium-2 series is. It's the Pickering series and another 4686 series. But we spent most of that day trying to just get rid of it again. He was convinced it was true, but he was not a spectroscopist, and Matthews wasn't, and I was. And we just fiddled and fiddled, fiddle, it wouldn't go away, so I said it's right. And then the other line was 2800, and I said, "Oh, my God." That was because I was completely-- I had tried a rocket spectrum of the sun many years ago and failed. But then I had a guy come to Caltech who worked there for about a half year from, I think, NRL named [Clearman?], I think, or [Kloorman?], who had an excellent spectrum and showed me this enormous 2800 emissions, so I knew about it.

Sullivan: 41:06

I see.

Greenstein: 41:07

Next, for the Air Force in a classified paper, in the early days of the ICBM, I had computed the ultraviolet spectrum of, say, essentially like a solar flare. And the idea was, what would it do to ionospheric communication if you communicated with an ICBM? This is connected with a blackout problem. So I knew the ultraviolet spectrum of stars. In fact, I knew all those damn lines, but I never thought of them.

Sullivan: 41:41

Then it just fit right in. Okay. Let me end with one overall question about the US radio astronomy getting started so late, relative to the British and the Australians. Do you have any thoughts on why that came about?

Greenstein: 42:05

Well, it was a real--

Sullivan: 42:08

We've about one minute on this tape.

Greenstein: 42:10

Very tragic. I think we were-- first of all, I wish we hadn't done 21 cm or whatever when it was found. It's a waste of time. The Europeans were going to do it. They did do it. Bok got everybody. All that came out, of course, is all the American leaders of radio astronomy, Bok students. That was really the output.

Sullivan: 42:31

Very little science.

Greenstein: 42:32

Very little science. Next, optical astronomy was so damn strong. Actually, the strong objection to our doing radio astronomy in Pasadena was not conflict with the optical observatory, but let the Easterners do it. We didn't think it would say important enough to deal with the great guys of cosmology. It didn't seem to have the same content.

Sullivan: 43:01

I see.

Greenstein: 43:02

That's a rather tragic thing. The Midwest observatories had been clobbered by weather for 100 years. We knew they had no future. It was suitable for Michigan and Ohio State to have it. So the big guns of astronomy, Lick and us, did not really take it sufficiently seriously, in spite of the fact that I was a protagonist from the beginning. Now, why did the radio engineers not follow it up after World War II? And it seems to me that that is a rather sad thing and that was just running away from World War II and not seeing the great opportunities.

Sullivan: 43:45

Are you saying, to maintain the Radiation Lab as a unit--?

Greenstein: 43:49

Well, maybe not that, but enough of the good scientists like Bolton stayed, an English man stayed in Australia. And a lot of the radar astronomers stayed in radio astronomy. Some of them corrupted it. I mean, it began in England, the emphasis on meteors was a silly waste of time and money. On the other hand, radar astronomy of the planets is a fantastically important thing. Very successful. But that came very late. I think we were just running away from the War and we had optical astronomy and it was enough. And the fact is that radio astronomy started in a half dozen places fairly quickly, all of them flops, at first Cornell, yet now Cornell is outstanding.

Sullivan: 44:37

That's the interview with Greenstein on 13, January, 1980.