Interview with Bart J. Bok, 5 October 1971
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Please bear in mind that: 1) This material is a transcript of the spoken word rather than a literary product; 2) An interview must be read with the awareness that different people's memories about an event will often differ, and that memories can change with time for many reasons including subsequent experiences, interactions with others, and one's feelings about an event.
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Sullivan
Ok, this is interviewing Dr. Bart Bok, October 5, 1971 at University of Virginia in Charlottesville. Tell me about the early days in radio astronomy.
Bok
A little background... I was among the audience when Karl Jansky gave his first lecture back in 1931 at the Columbia meeting of the American Astronomical Society [AAS]. And I always remember I said, "Well, what do you think of this fellow, he hears radio noises from the center of the Milky Way?" And Mrs. Bok said, "I don't think much of him." And that was the end of the beginning of radio astronomy. [Sullivan: 12/78 follow-up: "probably late ‘30s"]
Sullivan
Was this an invited paper?
Bok
No, that was a contributed paper at the meeting of the American Astronomical Society. So that shows you how we all started off being very dubious about it all. And then the second contact I had with radio astronomy came really through Otto Struve and Grote Reber. When Grote Reber was about to publish his paper on the galactic distribution - you probably remember that one in the Astrophysical Journal. He sent it into Otto Struve, and Otto Struve and I went to see Grote Reber's telescope in Wheaton, Illinois, had a look at it there, and then Struve said, "Now, I got a problem. This man has written a paper and I don't know whether I want to publish it. Yes or no?" He was the Editor of the Astrophysical Journal.
Sullivan
Where were you at this time?
Bok
I was at that time at Harvard. I said, "Well, Otto, you might remember what happened to [Meghnad] Saha’s famous paper." When Saha published his paper on the equilibrium of the ions and atoms in stellar atmospheres, it was refused by the Astrophysical Journal, by the Monthly Notices, and by one other journal. So he finally took it to the one place that had no refereeing which was, I think it was called Philosophical Magazine in Britain, and they published it. So I said to Otto, "What have you got to lose? This looks like a reasonable paper, you might as well publish it." And then I went on like all other astronomers dealing with my regular optical astronomy and went to South Africa.
Sullivan
Can I just ask what was the doubts about the paper? Was it just that it was on such a new subject?
Bok
A new subject. How to handle it and what to do about it and had that man really observed the whole thing or what was it- it was a fairly dubious thing as to what to do about it. And it was, of course, a very good idea to publish it and no one could check whether these data on the galactic center, with the strong radiation, were right or not.
Sullivan
And he was not a professional astronomer?
Bok
He was not a professional astronomer. No one knew him.
Sullivan
What was your impression when you went down to see his set-up?
Bok
I remember his mother. Yes, it was quite impressive and his mother said, "I hope that this thing gets out of the garden soon, for it interferes with my washing on Monday."
Sullivan
Well, Struve was impressed enough apparently.
Bok
Oh yes, the whole thing, yes. It went through and then got into the Astrophysical Journal all right. And then I went to South Africa and there I heard, I’d heard, of course, about Henk [Hendrik Christoffel] Van de Hulst, that it had been suggested that there might be a 21 cm line of neutral atomic hydrogen and while it had made a reasonable impression on me, I can't say that it had gone very far. And then, then I was in South Africa, I heard that [Edward Mills] Purcell and [Harold "Doc" Irving] Ewen were doing an experiment. And then I came back, about 6 months after the thing had been done. Jim Baker was the first one who wrote to me about it, that Doc Ewen had got the 21 cm line. I came back to Harvard and the first colloquium in the fall was one, a physics colloquium, where Ewen would talk about the new 21 cm line.
Sullivan
Which year was this now?
Bok
That was 1951. And, that September I went to that colloquium and sat in the back room just to find out what was cooking and what was going on. Ed Purcell had long been a friend of mine, not a close one, and at the end of the meeting Purcell, Ewen, and I got together, and I said, "What are you going to do? When are you going to set up one of these radio telescopes and go after it, and if I can help any, let know." And then Ewen said, "Well, I've got no plans." So then Purcell and Ewen and I got together, and Ewen had what we called a black box, which was the [receiving center ?] that they had used for getting the first radiation and Ewen had dealt in that in part with Merle Tuve, and Merle Tuve and the Carnegie Institution of Washington. And then there was a very peculiar luncheon where we were going to get that particular black box and where we were going to build a small 24 foot radio telescope which was being financed by Mrs. Agassiz for $25,000, which was a great gift from Mabel Agassiz, and she wanted to have something by which people would remember her husband, George R. Agassiz, and have an Agassiz telescope.
Sullivan
This was before the station existed?
Bok
Before the station... It was called the Oak Ridge Station in those days. And so, Mabel Agassiz had given the money for it and we were all set to go. And then there was a luncheon, and at the luncheon there was surprisingly also present Merle Tuve. And Merle Tuve said, for Doc Ewen was always a man who did all sorts of things in between, Merle Tuve said, "Well, Doc has just given all his old equipment to us," and then Doc Ewen said to me, "Well, it’s very much simpler for 10,000 bucks I can build now with my new Ewen-Knight company a little black box for you that you just push the buttons and have no more trouble, and I've given all the old junk to Merle Tuve." That was sort of a crisis, but the 10,000 bucks was found, and that was the beginning of radio astronomy. And at that time, I had three students and the three students in the field were David Heeschen, Ed [A. Edward] Lilley and,[T.] Kochu Menon. And they were the three who were thinking of helping me with this and getting into the radio astronomy field. And that particular instrument worked out reasonably well. Then the Navy entered into it, with the Office of Naval Research [ONR], and gave us support and then the [National] Science Foundation [NSF] looked for a fair-sized project to sort of start things off. And I said, "I am just what you want - a 60 footer for the radio station, at that time the George R. Agassiz Research Station - George R. Agassiz Observatory at Harvard, Mass., and we’ll put that one up, and we get some really good equipment going for that."
Sullivan
Was this the first big NSF project in astronomy?
Bok
That was in astronomy one of the first big ones. I think, one of the first big ones. And it was done by NSF - $100,000 by Alan Waterman, pretty well personally. And then more and more students came in...
Sullivan
Let me just ask about the 24 foot. You said that - what sort of work was done on it?
Bok
The 24 foot is the one with which we did the early work, about the 21 cm line and the integrated radiation of the Taurus Cloud where we got the first dust-to-gas ratio and the [???] in general of the 21 cm signal. And therefore, then - that was the first one, that was by Lilley mostly, but Heeschen was in on the part that dealt with the Gould’s Belt study - that was a joint paper. And then Heeschen started working on the galactic center in those days, and got the first absorption dip - the doubling of the line at the galactic center...
Sullivan
Well, he didn't see the absorption first, that was at NRL [Naval Research Laboratory], was it not?
Bok
NRL, I think, saw it first but he had a very good dip - he had published...
Sullivan
A very good frequency resolution?
Bok
Yes, a very good frequency resolution.
Sullivan
I still don't quite understand how you got so interested in radio astronomy.
Bok
Oh, very simple thing. Because by that time too, the radio astronomy - the Dutch had become quite busy with the spiral structure, and I was, of course, deeply involved in the spiral structure. Bill Morgan had just announced the optical spiral structure, and therefore here seemed to be a chance to really open completely new doorways to galactic research. And I had a feeling too that it wasn't only the spiral structure that entered into the picture, but that it was equally the general physics of the interstellar medium and one ought to look at the whole thing. There wasn't very much encouragement from some of my colleagues. I will not mention the next two by name, but two astronomers, one dead, one still very much alive - of very great distinction. [WS: Bok later identifies these] One [WS: G. Kuiper] of them said to me, "That was a silly thing to start your 24 footer at Harvard, because perfectly obvious by now that radio astronomy is just a flash in the pan. One single discovery and it's all over." That was one. The second one [WS: W. Baade] was another very distinguished astronomer, both Americans, who came to me and said, "You know it's really a pity that you are getting into radio astronomy now, Bart, because the Dutch have already finished." That was 1952. And therefore there was very little encouragement at that time.
Sullivan
Was that a Dutchman by any chance?
Bok
No. There was one Dutchman and one other one involved. All sorts of people involved - I will not give the names when they get recorded for posterity. But these were both by great men and brilliant remarks. And so that shows that the general climate was very poor.
Sullivan
But in any case you didn't let this sway you?
Bok
No, no, no. It worried me, I don't mind telling you that. Then the students became more and more interested, and in came that whole group of graduate students. And I told them we just have one of the finest things here by the tail. America needs it clearly and is going to develop in this field, and we need a lot of students in it and a lot of jobs. If you look around now, the students have done pretty well over there - Frank Drake came along, Nan [Nannielou H.] Dieter came along, Bob Davis entered the field, Bill [William E.] Howard [III] was there, Campbell Wade was there, so...
Sullivan
Sam [Samuel J.] Goldstein?
Bok
No, no, he was not a student of mine. No, no, Sam Goldstein, not. But all the other ones...
Sullivan
That’s right, he was Ed Lilley's.
Bok
Yes. But the first three were Lilley, Heeschen, and Menon. And then Nan Dieter came, Cam Wade came-let’s see I'm forgetting one or two very good ones in here. Oh, I can make a list up sometime, complete, but there are some other ones involved. But there were all together 11 graduate students in radio astronomy early. And then for a great variety of reasons I left Harvard Observatory and went to Australia.
Sullivan
Were there any other universities that had programs in radio astronomy at this time?
Bok
Very little.
Sullivan
NRL was going?
Bok
NRL was going. Carnegie was going under Merle Tuve, of course. Caltech was not really in the picture. Harold Weaver spent a year with us to sort of get underway for Berkeley, for Harold Weaver had in mind doing it at Berkeley. But that was about it apart from the Dutch...
Sullivan
So you didn't have much competition then?
Bok
No, no, there was no competition. And, as it proved later on, fortunately I had a good bunch of students, for when I left Harvard there came a dip in the graduate student production and from about 1957 on there were very few produced for quite awhile again, and this whole thing was between 1952 - 53 and 1956 - 57 about, when they all came through.
Sullivan
Were you head of the radio observatory?
Bok
Well, that was difficult to say. I ran the Agassiz Station. We never - I was Associate Director of Harvard Observatory and as such had the responsibility for the Agassiz Station. And then I was in the department affairs quite prominent. Shapley, I believe, was still Head of the Department at the time. So it was an early beginning and a vigorous one, but the sad part was that when I left Harvard, and I thought this had so much momentum that it couldn't be stopped, it slowed down until the later days when Ed Lilley built it up again, you know, when one got the Zuckermans and the Palmers and all the other ones coming in, of course. By that time it was going very nicely again.
Sullivan
Do you consider that the end of your active association, anyway?
Bok
That was the end of my active - of course, I was nominated for the job in Australia by the radio astronomers in Sydney, so I came as an optical astronomer to direct Mt. Stromlo, but as a clear nominee not of the optical astronomers, but of the radio astronomers. And this was principally Joe [Joseph L.] Pawsey who was back of that one, who had been long a good friend of mine and whom I had known for a good many years and with whom I attended symposia. And then in Australia we built up a graduate school very much along the same lines as what we had at Harvard. The thing that I felt strongly with all of my students, both at Harvard...
End of Tape 8B
Sullivan Tape 9A
Sullivan
So you were talking about in Australia - they nominated you to head the Radiophysics?
Bok
No, they nominated me to head Mt. Stromlo Observatory in Australia, but the nomination came from the side of the radio astronomers in Sydney - from the Radiophysics Lab.
Sullivan
I see, what did they have to do with it?
Bok
Oh, Pawsey was a member of the committee that did it, and Radiophysics, of course, was already a very famous institution by then. Frank Kerr, by the way, came to Harvard the year that I left and spent - was going to come for a doctor's degree and got homesick and went back, and now has a much more famous doctor’s degree than he would have had otherwise.
Sullivan
You mean in Sydney?
Bok
Yes. No, Melbourne, I think.
Sullivan
Oh yes, you're right. He got a master’s though at Harvard?
Bok
Yes, that’s right. Now the thing then in Australia - we had the same thing, for example, John Whiteoak, Marc Price, Ron Ekers, were among the students that came out of the group, and John Whiteoak, for example, wrote his thesis on optical astronomy rather than on radio astronomy, and I felt very strongly that this separation of the two is a very bad business, and it is nice to see that in some departments this separation is now being minimized. Like for example, the way you do it at the University of Maryland. For there has been far too much separation, complete from where the radio astronomers sit on one side, the optical on the other, don't talk to each other, carry their things on separately, and that is particularly a very bad thing when you deal with problems say of galactic structure. Now the Dutch system didn't have that. The Harvard system didn't have that. The Australian didn't, and yours now at Maryland doesn't have it. But there are still quite a few places where people...
Sullivan
This is just from my impression- what other places in the United States, what other schools do you think try to integrate it pretty much?
Bok
That's a rather delicate question to answer, I’m not sure I want to speak for publication.
Sullivan
Well, anything you don't want to publish, just tell me...
Bok
Caltech, for example, leans over in the radio towards the radio, and the optical towards the optical and there isn't always much intercommunication there. In Berkeley there is a reasonable amount, though again, not too much. But it is very fortunate that they have there Weaver, a man who was trained optically and in George Field, a man who is very much interested, of course, in the whole radio astronomical effort. But it is often done that the radio astronomers sort of are trained as physicists- electronic engineers, and then learn their astronomy in a couple of easy evenings.
Sullivan
I'd be interested in your opinion as an optical astronomer as to when exactly radio astronomy became acceptable to optical astronomers?
Bok
Oh, it became acceptable certainly at the time that Van de Hulst - or became noticed when Van de Hulst announced that there might be a 21 cm line. That was the first time when many of us began to sort of think maybe we ought to have a look at it - there ought to be something to be watched and not discouraged. In the solar field I think it became semi-respectable during World War II.
Sullivan
Oh, you mean those early observations?
Bok
Those early observations, for in particular everyone watched with great interest the developments both in the late 40's at Harvard and the developments at the Radiophysics Lab in Sydney and the Sydney ones were described at great length, there were colloquia given often, so this was all very important. On the other hand, there was still even in the 50s in Australia [???] a famous story, that on the day that John Bolton came and said he wanted to make a major announcement at the colloquium at Stromlo, and this is something you'd better not put in print because [Richard] Woolley is still alive - and the colloquium was - there was a tea before the colloquium- Woolley came to the tea and he said, "Well, John, I'm very sorry but I’m very busy with the calculation of a comet orbit and I haven't got the time to come to your colloquium today," [WS: 12/78 Interview, Bok attributes this story to Pawsey] and therefore, John Bolton received no encouragement for going on, and he found the first radio source by the ocean-reflecting technique.
Sullivan
Oh, that's what that was?
Bok
Right, that's what he were giving the colloquium on - and he wanted very much to hear what the astronomers had to say about it, but they were not available.
Sullivan
I think Woolley's dislike for radio astronomy is well known.
Bok
It's well known. Yes, yes.
Sullivan
That was what year now?
Bok
Gosh, I don't know what year that was.
Sullivan
'47?
Bok
It must have been '47 - ‘48 or thereabouts.
Sullivan
Thank you. That concludes the interview with Bart Bok at University of Virginia, October 5, 1971.