[Cover of Sullivan's book 2009, Cosmic Noise]
Sullivan's Cosmic Noise, Cambridge University Press, 2009


NATIONAL RADIO ASTRONOMY OBSERVATORY ARCHIVES

Papers of Woodruff T. Sullivan III: Tapes Series

Interview with Alexander G. Smith
At Haverford, PA, USA
21 June 1976
Interview time: 60 Minutes
Originally transcribed by Bonnie Jacobs (1977), retyped to digitize by Candice Waller (2017)

Note: The interview listed below was originally transcribed as part of Sullivan's research for his book, Cosmic Noise: A History of Early Radio Astronomy (Cambridge University Press, 2009). The original transcription was retyped to digitize in 2017, then reviewed, edited/corrected, and posted to the Web in 2017 by Ellen N. Bouton. Places where we are uncertain about what was said are indicated with parentheses and question mark (?).

We are grateful for the 2011 Herbert C. Pollock Award from Dudley Observatory which funded digitization of the original cassette tapes, and for a 2012 grant from American Institute of Physics, Center for the History of Physics, which funded the work of posting these interviews to the Web. 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.

Click start to listen to the audio for tape 45B of the 1976 interview.

Begin Tape 45B

Sullivan

This is talking with Alex Smith at the Haverford AAS meeting, 21st June 1976. Can you just tell me a little bit about your background before you got into radio astronomy?

Smith

I was educated as a physicist. I was always very keen and interested in astronomy. I suppose if the field had looked better I would have gone into it but in those days, which I guess you might say would have been in my late teens when I was selecting careers, and that sort of thing, it was a sort of situation where you could just about enumerate the number of decent jobs in astronomy in the country on the fingers of two hands.

Sullivan

You had come full circle.

Smith

Right, not quite full circle but we’re tending in that direction. So I was always very keenly interested in astronomy and did the usual bit of building and grinding my own mirrors, and building telescopes in my teens and so on and so forth. When push came to shove, I elected to go into physics and went into experimental physics and did my undergraduate work in the experimental physics program at MIT. And worked at the MIT Radiation Lab on radar, of course, during World War II. I graduated in the early stages of the American involvement in the War, and I think there were 17 students in my senior physics class at MIT. And I believe of the 17, 13 went into the Radiation Lab to work on the development of radar. As a matter of fact, I did my senior thesis over there. After the War -

Sullivan

Did you get your PhD there?

Smith

No. I got my bachelor’s degree there in ’43 and then stayed on 3 years during the remainder of the hostilities working at the Radiation Lab.

Sullivan

Do you know anything of Dicke’s work which was actually just after that?

Smith

Oh, I, you know, knew Dicke by name there, but I didn’t really know him. I wasn’t involved with any of that stuff. I was designing and testing magnetrons. We were very tightly compartmentalized. There was this need to know sort of concept to try and keep anybody from knowing any more than they absolutely had to know in order to do their job. As a matter of fact, my wife didn’t even know that I was working on radar. So when the Lab was winding down at the end of the War, Walter Gorde, who was there was going to Duke as a professor and he went around scouting up some graduate students and I was one of the ones he scouted up and made a very attractive offer. So I went down to Duke to do my PhD work in microwave spectroscopy. We did microwave spectroscopy on molecules for a couple of years there. I actually finished up my degree in only a couple of years – my Ph.D.

Sullivan

What year was this?

Smith

’48.

Sullivan

What molecules were you doing?

Smith

Oh, the ClCN - halogen cyanide, mostly is what I worked on. [? And ?] Didn’t do FCN. It wasn’t too practical at that time. ICN.

Sullivan

Did you envision at all this astronomical spectroscopy that has happened in the last 5 years?

Smith

Well in a way I did. I went to, with my Ph.D. clutched in my hand, immediately in ’48, went to the University of Florida where I have been ever since. I started in, as every PhD’s young dream is, as to keep on doing exactly what he did for his doctoral dissertation because it’s one thing he knows he can do or at least he thinks he knows he can do. And he’s not sure he can do anything else. And so I kept on working for several years in microwave spectroscopy at Florida. It eventually got to the point where it seemed like it had become more of a chemist’s game than a physicist’s game, that is, in essence the physicists had demonstrated the principle and developed the equipment and so on. And it became more and more a proposition of trying to dream up molecules whose rotation frequencies were in the right wavelength range and vapor pressure was such that it would work in microwave spectrograph. And as I say it seemed to be edging more toward a chemist’s game than a physicist’s game.

Sullivan

[?]

Smith

Yeah, oh yeah, all kind of boundary conditions that had to be met. So I became that involved in some work in atmosphere optics. This is in the early 50’s when I made the transition. And the Korean War, if you remember started up in that era, and I got involved as a leader actually of a rather large project in VHF electronics. I suppose it is no longer classified information, proximity fuse work, for the Navy and was on that rather intensively for about 3 years. And then got involved in some atmospheric optics work for the Air Force and the Army. This led more or less, you might say, to a renewal of my interest in astronomy. At least I was looking in the right direction.

Sullivan

But you said you had some inkling of the astronomical spectroscopy, how did that - ?

Smith

Ok, I forget the exact date, but I think it was like the middle 1950’s, pretty close around ’55, ’56. I made a proposal, which looking back on it, I think was probably ahead of its time, to do millimeter wave radio astronomy.

Sullivan

Spectral line were you thinking of?

Smith

Yeah. You know it was a reflection of my background in microwave astronomy and I’d become as I say, I’d started looking up again.

Sullivan

You had the hydrogen line -

Smith

And putting this together with my interests in microwave spectroscopy my interests in astronomy. I said, “Gee, you know, maybe there’s some future in trying to do this on the sky.”

Sullivan

You knew about the optical CHCN, I suppose?

Smith

Yeah.

Sullivan

And you figured why not? Now who was this proposal to?

Smith

I believe as I recall, it was to the Army for support. And it was a pretty full-blown proposal and got turned down [laughter]

Sullivan

This is about ’55, you think?

Smith

Somewhere in that vicinity.

Sullivan

Gee, do you think you could dig out a copy of that in your archives?

Smith

Oh, I could try.

Sullivan

That would be fascinating to see that. It was about that same time that Townes had an article which you probably know about now, at a symposium in England I think it was, suggesting various microwave lines as possibilities.

Smith

Yeah, of course Townes was one of our competitors in the microwave spectroscopy business.

Sullivan

Yeah, but you’re the first person I’ve heard of that really wanted to get a full-scale program going. So having that turned down you decided to just give it up?

Smith

Well, just about this time, Tom Carr who had done his undergraduate work and his Master’s thesis at the University of Florida, he had started to do graduate work at Chicago and then was stopped because of illness. He went through a period of rather uncertain health. And he started to do some work at Chicago and had to stop because of his health and then somewhat later he tried again at Duke and had to stop again because of his health. And then he was involved in the Bikini tests and then I guess it was roughly after, that he went to what then was Cape Canaveral, I guess it again is Canaveral, and became very heavily involved as a civil service scientist in their radio propagation work down there. And then once more he became very interested in going back to school and finishing up his PhD and he contacted us in what was then just the Department of Physics. It later became Physics and Astronomy at the University of Florida. So he came up – there was some kind of a meeting there of some radio types, and I forget now what it was. I think it was sponsored by the College of Engineering. Anyhow, a lot of radio types running around all over the place. And so he came up for this occasion and we talked with some of those radio types to try to get some advice about what, if anything we could do in the way of radio astronomy that wouldn’t cost a million dollars. And I just at the moment can’t think of his name but there was a Frenchman there who did some early observing. In fact, he wrote a chapter in a book, the University of Chicago series -

Sullivan

Oh yes, the Kuiper series?

Smith

Yeah.

Sullivan

Steinberg, maybe?

Smith

No. Wasn’t Steinberg. He was very active for a short while in radio astronomy, particularly in observing Jupiter. Then he went to the Bureau of Standards and I haven’t heard anything from him since. I don’t know what happened to him but he was a very clever, very genius guy, very full of ideas. And he was the principal one we talked to and he told us about the very recent discovery of the Jupiter radiation and said you know, “Gee, here’s something that’s strong enough that you could observe, with relatively simple antennas, it just seems made to order.” So we said, “Swell.” And we got a few hundred bucks from the Physics Department budget which was a significant fraction of the Physics Department budget in those days.

Sullivan

This was about how long after Burke and Franklin’s - ?

Smith

Less than a year, 8 or 9 months.

Sullivan

Before we get off on this I just have another question about your proposal for millimeter spectroscopy. Can you remember which molecules you were particularly interested in looking at, what frequencies?

Smith

No. I just don’t remember the details.

Sullivan

It would be good to dig that up.

Smith

I’ll have to see if I can’t find that. It would be interesting to me. I haven’t seen that for a long time. Anyhow, we put up – we had a student observatory which I had been particularly responsible, optical observatory. We had gotten a gift of a very fine 8” Clarke, actually the lens was by Clarke, refractor. And had put up a student observatory on campus with the principle (?) essentially the only instrument. So Tom Carr and I, helped very shortly by Colin Barrow who came over from England as a Fulbright student, put up an array of dipole broadside array, I think it was something like 8 quarter wave or half wave dipole. You know the sort of thing you get out of the Radio Amateur’s Handbook – at 18 MHz, it was then megacycles, in order to listen for Jupiter. We got the thing on the air in 1956. But our first list was I guess about the tail end of the Jupiter apparition and we had our first real full apparition in 1957 which by great good fortune was timed when Jupiter was extremely active. We got enough results so that we got one or two papers out of it.

Sullivan

Right. I was just noticing your first paper I think is ’57 Nature -

Smith

Right.

Sullivan

And what were your results at that time?

Smith

We detected copious quantities of Jupiter radiation so that we were able to plot histograms of the current probability vs. central meridian longitude. And, of course, confirmed the fact that there were certain apparent source regions as people had come to call the 3 primary regions from which, or at least central meridian longitudes, which seemed to generate more Jupiter noise when turned toward the earth. And we also got a good measure of the rotation period and which put together really with the earlier results gave us a better handle on the rotation period than had been possible because we had simply extended the time baseline and that always give you -

Sullivan

You mean Shane’s results?

Smith

Yeah, Shane’s results. We then proposed, I guess one of our earlier results, was proposing a system 3 longitude system based on this new 1957.0 how it came to be designated because 0 meridian was on the central meridian and on New Year’s January 1, 1957. And proposed this longitude system with the rotational period that we had determined.

Sullivan

Is that the one that has come to be known as System 3?

Smith

Yeah. The radio system as System 3 of course has been revised. In fact, it just very recently has been revised again to a 1965.0 system. Jim Warwick is the principal (?) detected the latest revision.

Sullivan

I noticed here that you talked about this System 3 at an APS meeting and then published it in Ap.J. Apparently you felt like you should talk more to the physicists than the astronomers.

Smith

Well, we were physicists [laughter]

Sullivan

Yeah, that’s how you thought of yourself.

Smith

Yeah, we were members of the Physical Society at that point I guess rather than the Astronomical Society. I don’t really remember when I joined the Astronomical Society. It’s like so many people, of course, who came into astronomy through a physics background. That was where we’d been giving papers, the natural thing to do.

Sullivan

That’s also the same paper in which you in the abstract mention a sporadic radiation from Saturn. What can you tell me about that?

Smith

Of course, it’s a very natural extrapolation since the planets – or at least Saturn is I guess one would say, superficially the planet that would most closely resemble is Jupiter and if you know all these fireworks coming from Jupiter it doesn’t take an awfully lot of ingenuity to say, well, you know, maybe Saturn does it too. And so we early on started listening to Saturn and also to Uranus for obviously the same reason. On a number of occasions, we thought that we possibly had heard bursts coming from Saturn. And when we put together these occurrences they even gave a sensible rotation period. But the radiation was always so weak and so infrequent, nothing like the strong persistent noise storm which one frequently gets from Jupiter, that we were never willing to stake our reputation on it and say with any degree of certainty that we had heard noise. We simply reported it as a possibility. But we never made any positive claim that we had heard noise from Saturn. Now I think the Yale people were in exactly the same boat. Harlan Smith and Jim Douglas at Yale. They had the same sort of thing and unfortunately none of our observations coincided, the Yale and Florida observations. It remained in that status essentially indefinitely.

Sullivan

Did anyone try and make a confirming program or anything like that?

Smith

Well, we did. We observed Saturn in more recent years with more powerful equipment and sort of had, I guess you might say, the uncomfortable result that the more powerful the equipment was the less Saturn we seem to receive. (laughter) Of course, finally last year I guess it was, Brown at Goddard apparently succeeded in detecting Saturn bursts in the satellite records. And since the radiation bursts as he reported them seemed to peak in the vicinity of 1 MHz, it seemed quite possible that they may not really be observable from the ground. We’ve got an antenna now which was built in part to listen to Saturn and in probably in larger part to back up the RA 2 frequencies. 6.55 MHz, and we have done a fair amount of Saturn listening with that antenna without getting much satisfaction. And it may simply be that the Saturn radiation is at sufficiently low frequencies so that it just doesn’t essentially penetrate the ionosphere in detectable amounts.

Sullivan

What about the milieu at that time in the late 50s? It seems to me like people were claiming comets for giving off low frequency radiation and Venus had bursts. I think it was Kraus that was claiming that. There were a lot of these things – just a little bit too much enthusiasm?

Smith

Kraus had fitted actually the Jupiter radiation – the Venus radiation to an interferometer pattern. You see, we didn’t even have that comfort because we were not using interferometry. Well, we had interferometry but we were not using them, I guess you might say routinely on Jupiter. Basically, we didn’t feel it was the way to go.

Sullivan

Why was that?

Smith

I think probably several reasons. One was that we felt that the interferometer pattern was sort of restrictive in terms of observing the actual morphology. You know, you’re super-imposing the fringe pattern on top of the morphology of the Jupiter noise storm and we were really more interested in mapping the Jupiter noise storm without pollution of the interferometer pattern. I guess this was one reason. And another reason was we didn’t think we needed it because the mode of operation that we developed early on was to always work with an operator. A live operator to identify the noise and mark it on the records, eliminate interference if possible if it came along. And our experience was that we could identify genuine Jupiter noise with essentially 100% accuracy with the live operator technique. I think this was confirmed to a certain extent, I’m a little hesitant to say this, by Jim Douglas’ experience at Yale, where they did try to operate with interferometers and as I understood the situation, essentially got so little data that in order to complete his doctoral dissertation, Jim Douglas had to write us for our data. So this made us think we were really on the right track.

Sullivan

So you are saying that Jupiter was in view so much less time with the small fringes of the interferometer that you lost a lot of data?

Smith

Right. And when you combine the highly sporadic nature of the Jupiter radiation with what I guess you could term the sporadic nature of an interferometer pattern you require double coincidence in order to get your data [laughter].

Sullivan

And in fact, what your interests were in seems to be time resolution which the single antenna could do as well. Rather than angular resolution assuming it all came from Jupiter.

Smith

Yeah. Assuming you could identify your noise – it’s sufficiently distinctive that we felt we could do it with essentially 100% accuracy. And after we got our Chile station in operation we had a way of confirming this. It’s sort of amusing that we would have instances where we would have Jupiter noise maybe, let’s say, a few centimeters high above the baseline in the face of thunderstorm static that was penning the pen at full scale and the observer would mark in the log, “Gee, I’m almost sure I hear Jupiter under all this thunderstorm noise.” And later when we’d compare this record with the Chile record sure enough this was right in the middle of a Jupiter noise storm. It’s surprising that once you’ve listened to it there’s virtually no possibility of confusing the Jupiter noise with terrestrial static.

Sullivan

Just from listening though?

Smith

Yes, just from listening. You can well believe we spent a lot of time trying to think of circuitry that would do this but we never found anything that would do it as well as graduate student. It’s rather odd, the thing which is most apt to be confused with it orally is station. What you probably heard, if you done much radio listening, a station trying to fade in from a distance and going, “sh sh sh sh sh sh sh sh.” That sounds like Jupiter. If all you can do is listen there are many times when your station starts to fade and create interference when you wouldn’t be sure it was Jupiter. You see, there you’ve got a hand on the situation so all you do is grab hold of a knob on the set and turn it a little. And if the station goes away and Jupiter doesn’t. So this, of course, is what the observers are trained to do.

Sullivan

Can you give an example as you’ve already done, the main difference between what Jupiter sounds like and what thunderstorm - ?

Smith

Well, of course, everybody has heard thunderstorms on the radio. You get these very sharp crashes. The Jupiter noise, well there are really two types that observers distinguish now, the L bursts, the “L” standing for long and the S bursts, obvious “S” stands for short. The L bursts, the best analogy that I know of I think is one that Colin (Barrow?) was responsible for at least the first time I recall hearing of it was waves breaking on a beach. Ocean waves breaking on a beach – just sort of slow roaring rumbling sound – sh…. That sort of thing. Nothing at all like the sharp crash that you get from terrestrial static. And it’s almost impossible vocally to emulate that S bursts but the best analogy there that I’ve heard anyone – maybe I even thought of this one – was hail falling on a tin roof. It would occur to many Floridians. But yeah, that’s just a very sharp rattling kind of sound, again not at all likely to be confused. I guess the L bursts are too long. The wave form is not steep enough to confuse with terrestrial static and I guess with the S bursts the wave front is too steep. They’re both in different time domains from the terrestrial static.

Sullivan

Ok, we got off on this when I brought up the question of -

Smith

Of Saturn.

Sullivan

Well, of Venus.

Smith

Of Venus, yes.

Sullivan

People were going wild it seems with these low frequency detections of solar system noise.

Smith

The point being that John Kraus felt that he had this radiation from Venus. He was fairly positive about the identification because it perfectly well matched his interferometer pattern. But apparently, you know in the light of hindsight which is always the best kind, it must have been terrestrial interference as he rather soon recognized himself. And we always felt that basically the problem was that he did his, as I recall the situation, he did his observing in the evening at an eastern elongation of Venus and we tried to confirm it. We always did our observing at a western elongation just before dawn in morning, which from a physiological point of view is less desirable. But from an ionospheric point of view it’s vastly quieter. That’s, of course, the quietest time at decameter wavelengths, just before dawn and of course in the late afternoon is the noisiest time.

Sullivan

You tried to confirm these Venus - ?

Smith

Oh yes, we put in a lot of time observing Venus as a result of Kraus’ observations.

Sullivan

Did you ever publish not finding it?

Smith

Yes, I believe so. Surely we did.

Sullivan

I didn’t find it in the abstracts anyway.

Smith

Yeah. Surely we did. We had a paper in which we summarize a number of, I think, it was in Vol. 134 of Ap.J.

Sullivan

Ok, I only went up to 1960 so this is getting later.

Smith

Yeah, this would probably have been one of our papers in the early 60s in which we summarize observations of several planets in one paper. And I’m sure that we reported the negative results on Venus.

Sullivan

What about comets? It seems like a lot of people were enthusiastic over – there was one particular comet, ’58 or so -

Smith

Was it (?) the one that had the spike?

Sullivan

No, that was ’65 or so I think.

Smith

No. This was ’57.

Sullivan

Ok, I’ve got them mixed up. Anyway, there was a comet (?) there were several reports but they disagreed with each other as to the nature of it.

Smith

We tried to observe – we did some observing of a comet, passage of a comet, and I don’t remember what year it was. It conceivably could have – no, I think it must have been later. Yeah, it was later than that because I remember we had moved our observatory from the original site when we had this campaign on the comet. Of course, we had an interferometer operation at that time, we never had any interferometer at the old site. We observed – this initial site with the student observatory we only observed there about 2 apparitions then we moved. We very quickly ran out of room for antennas. Then we moved to another site still on campus but on the fringe of campus on agriculture land and we had built an interferometer there, 22 MHz interferometer, by the time we tried to do these comet observations. And so I don’t remember exactly what year it was but I do remember that we, among others, tried to make observations of this comet and came up absolutely nothing.

Sullivan

Do you think that there were these various (?) probably over-enthusiastic interpretations simply because people were not appreciating the problems of noise interference?

Smith

Probably so because, of course, of all the radio astronomical bands it’s the noisiest from a number of points of view the harder – I guess most of us think of the decametric spectrum lies right across the ordinary short-wave band where of course there is a tremendous amount of activity. There’s also bands in there where people use all kinds of infernal machines like (?) machines and plywood machines where they use electromagnetic feeding for gluing the plywood and so on. So there’s an awful lot of manmade interference and power line leakage, leaking neon signs. I hate to tell you how many hours we spent driving up and down highways with portable radios looking for which motel it was whose neon sign was leaking and causing interference at the radio observatory. We’d notice it particularly every time there was little fog or a little mist that would incur the breakdown of these signs, and sometimes essentially put us out of business. Since we couldn’t observe we’d jump in a car and drive up and down the road looking for the sign.

Sullivan

And what was your procedure when you found it?

Smith

Ask then to fix it.

Sullivan

And would they usually fix it?

Smith

Astonishingly cooperative and very apologetic. We never ran into anybody who was the least bit ugly about it.

Sullivan

Didn’t know my sign can do that!

Smith

No, glad you told us. We’ll do something about it. And they did. Amazing how cooperative people were.

Sullivan

I find in the AJ in 1960 University of Florida radio observatory report which apparently is the first time that you felt like you were an astronomical observatory and should put a report in.

Smith

Amazing. That was the first time (?) subscribed to the journal. We didn’t know there was such a thing as a report. [laughter]

Sullivan

But all of this that you had done in the late 50’s was planetary radio astronomy? In the comet perhaps?

Smith

Yes. Yeah. The comet was probably early 60’s.

Sullivan

Now what about a paper in Nature in ’59 by Smith, Carr and Perkins on a solar burst you received at night?

Smith

The Type III solar bursts are like the Jupiter bursts. If you’ve ever heard one, you always recognize it as it’s hardly anything else you can confuse it with because it has this “shhhh” build up and then this beautiful exponential follow-up shhhh. I forget who was observing, don’t remember whether it was I or who it was, anyhow heard this humongous solar burst at 3:00 in the morning or some time like that. Unmistakably a solar burst. And it seemed passing strange, and since the sun was many hours from rising. So as I recall we corresponded with some solar observatories around the other side of the earth and sure enough there was this big burst at that time. We thought this was a curious enough propagation phenomenon so we wrote up a little note and published it in Nature calling attention to the fact that by golly such things can happen.

Sullivan

I’ve never heard of anything. Have you ever seen anyone else report such a thing?

Smith

No, I haven’t but I suspect people probably were. You know it’s the same sort of thing we used to hear reports when I was working on radar during the War about people receiving 10-cm radar all the way across the Indian Ocean by some kind of peculiar ducting effect. Oh, incidentally, along the same line, I very well remember on a number of occasions listening to Jupiter noise storms which continued after Jupiter had set. One I remember following until it was something like 10 or 12 degrees below the horizon. It just kept right on. Peculiar, obviously some peculiar ducting effect in the ionosphere.

Sullivan

What about the paper Carr, Smith and Bollhagen in Phys. Rev. Letters in 1960 in which you correlate the Jupiter bursts with the earth’s geomagnetic activity and thereby deduce that the solar wind essentially that is influencing these things? Were you the first to establish that would you say?

Smith

Well, I think about the same time, as I recall, Jim Warwick was doing some work along similar lines. Probably nearly simultaneously. It’s one of those strange things like geophysical correlations are apt to be. And we worked intensively on this since that time. As a matter of fact, we’ve got two doctoral students, this is not their sole thesis work but it’s in each case a fairly significant part of their thesis work, doing it right now. Looking for correlation between the Jovian decametric emission and geophysical events or solar events. We’re getting a little more sophisticated now in the sense that we’re trying to tie the thing together with models of the solar wind and propagation times of solar wind out to Jupiter and all that kind of stuff. Making use of the spacecraft observations (?) But it’s one of those strange things because you can find periods in the data when you seemingly get striking correlations. And you can find other periods where it doesn’t look like anything.

Sullivan

Just a strong burst and yet there’s no correlation.

Smith

And we think, one of these two doctoral students that I’m talking about, may have come up with the answer to this in that he investigated a period in which there was very stable interplanetary magnetic field, very stable solar sector field, and found the correlation during this period of very unusually stable interplanetary magnetic field pattern. Investigated another period more or less as a control, didn’t find the correlation so maybe this is the answer. That if you have a stable interplanetary field then the situation is well enough organized so that you can find a correlation. But it’s a kind of frustrating thing. At this particular moment in time, I wouldn’t state my reputation on the fact there is a definite correlation but we’ve certainly been suspicious enough, had enough positive results over the years that we’re still working on it and trying to demonstrate the cause and effect of the relationship.

Sullivan

Was there any other correlations in those early days of solar activity and Jovian activity?

Smith

There’s this long term variation in the mean level of the Jupiter activity as no small effect. In fact, if you average the probability of occurrence of the Jupiter noise over all the longitudes of Jupiter to wipe out the source effect so that you just kind of get – do this over an apparition so that you just kind of get an apparition wide mean rate of radiation independent of what longitude Jupiter happens to be turned toward the earth you find that between Jupiter maximum and Jupiter minimum there is about an order of magnitude difference in the probability of occurrence. As I said a little while ago we were lucky in a sense in that we had our first real full apparition in 1957 which was a good one but it was on the declining leg, very sharply declining leg of this. And ’58 and ’59 we got so little radiation that Tom Carr stroked his chin and said, “My God, we’re studying a dying comet.” He was particularly concerned (?) It came back and in the early 60’s, around ’63, just had tremendous rate of radiation. Then we went through another minimum and now once more it’s back up. Last year was as big as the ’63 minimum. So there seems to be a long term cyclic change in Jupiter’s mean rate of emissions or at least in our mean rate of receiving Jupiter’s (?)

End Tape 45B

Click start to listen to the audio for tape 46A of the 1976 interview.

Begin Tape 46A

Sullivan

Continuing with Alex Smith on 21st ’76. Now you were talking about the periodicity actually seems to be what?

Smith

Seems to be 11 or 12 years. The peaks are not terribly sharp as nearly as one can determine. It seems to be a periodicity of something like 11 or 12 years. And so you say not only “ah ha” but, “ah ha, ah ha” because that matches two possible periods. It could be the orbital period of Jupiter or it could be the sunspot period. Of course, as you know, many times in astronomical history people have pointed a finger at Jupiter and said, “Well, obviously Jupiter causes sunspots because the sunspot period is the same as the orbital period,” you know, in round numbers of Jupiter.

Sullivan

And the phase is the same as the solar (?)

Smith

No, it’s anti. At solar maximum you get a minimum of Jupiter noise and at solar minimum, of course we’re headed toward minimum now and the Jupiter noise is peaking up again. So it’s anti-correlation. And one thing that has always intrigued me is the fact that the Jupiter curve is very close to looking like the cosmic ray curve which has the same kind of inverse – this is the galactic component -

Sullivan

Modulation on the extragalactic cosmic rays?

Smith

Yeah. The long-term Jupiter curve is not at all dissimilar to a long-term cosmic ray, non-solar cosmic ray, curve. But in any event this is one of the problems. Is it correlated with the sunspot cycle, which was ours and everybody else’s first guess? But Tom Carr I think has shown – he’s been very interested in this effect. I think he has shown more and more convincingly to a point where I guess if I were a gambling man I’d say it’s now 75% certain in my mind that the correlation is really with the orbital motion of Jupiter rather than with the sunspot cycle.

Sullivan

But this was not established in the early 60’s, of course. It’s taken another 15 years - ?

Smith

Right. As close as the periods are it takes quite a while, you see, before they – the phase starts getting separated well enough so that you can say with any certainty.

Sullivan

Ok, there’s one other thing you haven’t mentioned and that was an article in Nature in ’60 in which you had two arrays 7,000 km apart. What was that?

Smith

Well, it turns out I guess historically that we were the first group to successfully operate a VLBI. And again this was Tom Carr. It was his idea. And we set up a VLBI to try to resolve the Jupiter sources between the radio observatory which at that time was still on the fringe of the campus on the agriculture experiments station -

Sullivan

This was Gainesville?

Smith

Still in Gainesville. Between the Gainesville Station and a set of antennas that we put up on the campus of Central Florida Junior College in Ocala which is about 30 miles to the south. And the initial idea was to use a telephone line to combine the signals. Well, we had so much trouble with the telephone line it never did really work, that Tom Carr said well, “Shoot, let’s just do away with the telephone line and independently record the signals on tape recorder with time hacks from WWV and recombine the signals.” This worked.

Sullivan

When was this?

Smith

This would have been ’64, I guess.

Sullivan

Ok, so this is after this one that I’m referring to in the 1960 Nature article. This was a 7,000km baseline that you had.

Smith

Well, that would have had to have been efforts to correlate the morphology of the bursts. At the two stations separated – it’s about 7,050km from the Gainesville Station to the Chile Station. And we were simply studying burst morphology and seeing if we could correlate individual bursts over that distance.

Sullivan

Ok. But back to the VLBI. This is interesting. So about ’64 -

Smith

Yeah, which was about a year before the microwave groups. We were able to do the thing with our relatively crude equipment because we were looking at such a powerful source, you see.

Sullivan

Very interesting.

Smith

And it was about a year before the microwave groups got their -

Sullivan

And where did you publish this?

Smith

The first mention of this was published in rather obscure and unusual source of – I think it was NERM.

Sullivan

Yeah, I know that – Northeast Regional Electronics Magazine.

Smith

Right. And they presented a paper on it at that meeting and it was published as an extended abstract. Then, of course, in ’59 we had set up… Well, the upshot of this was that we were nowhere alike resolving the source with this 30-mile baseline from Gainesville to Ocala. It was clear that the source was totally unresolved. So the next thing we did was to put a station at St. Petersberg because by that time one of our graduate students, one of our doctoral students, Will Block, had gotten a PhD and our decametric program was on the faculty at Florida Presbyterian which has now been bought out and is Eckard College, after the Eckard Drug stores. Anyhow, Will Block was at Florida Presbyterian, now Eckard and so he put up a VLBI terminus there which gave us a baseline of about 150 miles. And we operated that for a couple of seasons. And again it was very clear that the sources were not being resolved. And so then I guess the next step was we put one in Bowling Green, Kentucky, because by that time Frank Six had graduated from our program with his PhD and was chairman of the department at Bowling Green. And I think this is about 800 miles. Again, no evidence of resolution in the sources operating this baseline for a couple of years. Well, in 1959 we put up the Chile station. It was sitting down there all the time so then finally we made the big leap, you see, and put a VLBI terminus in Chile Station. And most of our operating since that time has been either from Bowling Green to Chile or from Florida to Chile. We get about 500,000 wavelengths from Bowling Green to Chile about little over 400,000 wavelengths from Florida to Chile.

Sullivan

Are any of them being resolved?

Smith

No.

Sullivan

Still not?

Smith

We got a 10th of a second arc resolution with the Bowling Green to Chile baseline and no evidence of resolution.

Sullivan

Now Radhakrishnan and Morris in the early ‘60s at Caltech were looking at Jupiter bursts in the decimetric.

Smith

Not bursts.

Sullivan

Well not bursts. I guess, that’s right. It was just the normal radiation.

Smith

They were looking at the microwave radiation. But that’s not bursting.

Sullivan

Right. But they were establishing, however, that Jupiter… That’s right -

Smith

The decimetric source is like 3 times the size of the planet. In other words, they were seeing Frank Drake’s radiation belts.

Sullivan

Right. And that it was tilted also.

Smith

10 degrees to the rotational axis.

Sullivan

Right. So what you were doing was not connected with this even though that was high resolution work – angular resolution?

Smith

Right. Yeah, we were looking at a totally different phenomenon. Well, this was one of the interesting contrasts that we pointed out a number of times in print. The fact that the decimetric source is humongous like 3 times the size of the planet itself. Whereas the decametric source cannot be resolved even with a baseline which give you 10th arc second resolution. And we’ve got some high time resolution data which, if you interpret it in the usual way, the way that people argue about the sizes of the quasars now, apparently it’s been investigated and with all the relativistic corrections and everything else and is honest-to-gosh legitimate – the light travel time argument – we have structure in the bursts, rises or falls, front end of tail end pulses, of the order of 10 microseconds. Of course, this puts an even smaller limitation on the active region than the long baseline interferometry does.

Sullivan

Just for comparison what would terrestrial lightening be in terms of this time change?

Smith

It’s much slower than that. I couldn’t really quote you a number on that – I don’t have one in my head. But it’s much slower than that. These are the S bursts, you see.

Sullivan

Well, 10 microseconds, that’s what, 3 meters?

Smith

No. It’s more than that.

Sullivan

Oh, it’s 3,000 meters – 3 km.

Smith

3 km, right.

Sullivan

Was there anything else? We’ve covered everything I think in the late ‘50s. Was there anything else up to ’63 or so?

Smith

One thing that might be interesting from a historical point of view is the Chile station. At the time it went into operation, unless our information is incorrect, and nobody has ever challenged this. We believe it was the first active radio observatory, radio astronomical observatory, on the continent of South America, that went into operation on the continent of South America.

Sullivan

I see. And that was ’59 or something?

Smith

Well, we built it in the summer of ’59 and put it into operation in the Spring of ’60, the first apparition of Jupiter after the observatory -

Sullivan

Where in Chile is it?

Smith

It’s at – near the historic town of Maipu. It’s historic because the final battle for the liberation of Chile was fought at Maipu and there are monuments there, generals on horseback and so on – Bernardo (?) And it’s like our station at the University of Florida was, it’s on University of Chile farmland on their agriculture experiment station. It’s about 18 miles from Santiago.

Sullivan

So how would you summarize, the contribution that your group has made to the Jovian decametric game up until the early ‘60s in particular?

Smith

Well, I would say our work, some of the important things was our work on rotation periods, the system 3 and the refinement of the rotation period. And the demonstration – just again it was one of these things virtually simultaneous – just about the same time the Yale people became aware of it, that the doggone rotation period was changing. Which was rather startling. This became evident in the early 60’s. The demonstration by simultaneous observations from both hemispheres that the polarization phenomenon that were being observed were not terrestrial in origin. This was I think one of the earliest big inputs from the Chilean station. Of course, you’d have reversed polarization phenomena if they were terrestrial in origin. And we observed the same polarization phenomena from both stations indicating that they were not terrestrial in origin. I guess we’ve done a lot of work on the burst morphology, the demonstration of the existence of the two classes of bursts, the L bursts and the S bursts, the first successful long baseline interferometry of Jupiter, or of anything for that matter.

Sullivan

Ok, well that’s a long enough list. What other groups were there working on Jupiter in the late 50’s besides the ones that have been mentioned already – in the whole world, I mean?

Smith

Yale was I guess the chief competitor. And a little later Jim Warwick at Colorado with Dulk as a graduate student, later a faculty member, got into the game in a very complementary rather than a competitive way by doing this beautiful wide range spectroscopy.

Sullivan

Yeah, and you’ve always stuck to one frequency band pretty much?

Smith

We’re doing a great deal of spectrographic work now. But again, it’s not competitive with the sort of thing that Jim Warwick has been doing. Because what we’re doing now is very – instead of the broad stuff, we’re doing very high resolution in both time and wavelength type of…where we record the stuff on videotape and later massage it at leisure. You know, one of those things where you take 10 minutes of data and a graduate student spends 3 years analyzing it.

Sullivan

Were there any other groups?

Smith

[long pause] Barrow when he left us went to Florida State. I don’t remember exactly when he got into business. But he set up a Jupiter monitoring operation at Florida State. It wouldn’t have been much later than the early ‘60s. Well, certainly in the early ‘60s, but exactly what year I don’t know.

Sullivan

There was nothing in Australia or in Europe?

Smith

Well, Shain continued to do some Jupiter observing. I’ve always had the impression he never did it terribly intensively. But he continued doing some Jupiter observing. As a matter of fact, Tommy Carr went over to Australia, again right around the early ‘60s – ’60, ’61, sometime in there. And spent some months over there with the Australians and I guess in a way kind of got them stirred up again so that for a little while they did do a fair amount of Jupiter observing. It didn’t seem again to last terribly long. The long-standing programs – there were a number of people because basically it’s a sort of simple kind of observation. A number of people who dove in and dove out. You know, they put up an antenna and listened for a year and maybe published a Note someplace and then you never heard any more about it. But the long-standing programs were our program. The Yale program until really it more or less bodily moved to Texas and Jim Douglas who is still doing it. And in Colorado.

Sullivan

When did that happen?

Smith

When he went to Texas – that must have been something like ’65.

Sullivan

So those three American programs – the Russians weren’t doing anything along this line?

Smith

Surprisingly not because Braude has had this humongous low frequency enterprise. For some reason I get a Christmas card from him every Christmas.

Sullivan

He must like yours.

Smith

But in any event, no. They’ve never seem to have done any appreciable… Now Rijhimma in Finland did some strictly spectroscopic work, very nice spectroscopic work at high speed, again high speed high resolution spectroscopic work. And then he came over and did a couple of years of sabbatical with us.

Sullivan

When was this now?

Smith

Oh, again middle ‘60s.

Sullivan

I see, so this is still later?

Smith

Yeah. And then spent a couple of years with Jim Warwick at Colorado before going back to Finland.

Sullivan

So starting with Burke and Franklin this was pretty much exclusively an American, except for Shain’s -

Smith

Yeah, except for some sporadic activity in Australia.

Sullivan

Interesting.

Smith

Yeah, it was pretty much… well, now (?) and McCullough in, of all places, in Tasmania did some very low frequency stuff. That, I guess, would have started in the early 60’s.

Sullivan

Where was that published?

Smith

Mostly, I think, in the Australian Journal of Physics.

Sullivan

Probably, yeah. Well any other comments that you can think of in the overall scene? I think we’ve been pretty thorough here.

Smith

Nothing that comes to my mind unless you have other questions.

Sullivan

No, I don’t have. Thank you very much. That concludes the interview with Alex Smith at the AAS meeting in Haverford on June 21st 1976.

End Tape 46A


Modified on Wednesday, 05-Jul-2017 07:18:03 EDT by Ellen Bouton, Archivist (Questions or feedback)