Interview with Fred Hoyle on 22 May 1988

Sullivan: 00:00

Okay, this is speaking with Sir Fred Hoyle at Bologna on 22 May 1988. Well, let me start by asking you [inaudible].

Hoyle: 00:09

Well, my work during the War was to basically write software for the instruments that already existed. My first problem when I arrived there, down on the English south coast in 1940, was to use equipment that had already been designed and fitted to solve a problem for which it was not originally designed. I mean, in other words, to find out ways of using what already existed. We were never in the position that we were able to design equipment to suit ourselves. We had to use what had been sort of decided upon for other reasons.

Sullivan: 01:03

What do you mean by software now?

Hoyle: 01:04

Well, I'll give you an example. We had equipment that really was quite excellent for detecting enemy aircraft coming in to attack ships, detecting them at an early--  giving early warning at great range. That worked so well that even though it had been designed about 1938, it continued right through to 1945. But--

Sullivan: 01:36

This is the Chain Home system that you're talking about?

Hoyle: 01:38

It's a long-wave detector. It turns out that long waves had very little losses. Their receivers were good and they could get a lot of power out. And so this was an excellent system. Indeed, they used to say that if that system ever went out for any reason, became unserviceable, the whole ship would become nervy from the captain downwards right to the last rating. By the end of the War, that was the situation. But unfortunately, that set wouldn't give the height of the incoming aircraft. So when they got to the point that they had ships that could carry interception aircraft, it became a very crucial matter to be able to know in advance what the height of the incoming enemy aircraft were, heights were. And so I was asked when I arrived there, was there any way in which this equipment could be used together with some simple [ready reckoner?] for the radar officer whereby he could judge what the height would be. Well, I soon found that there was a way to do this, that you could from basically the range of detection in further height. There were some problems in that it demanded a knowledge of the efficiency of the equipment. And naturally, that efficiency was variable from one ship to another according to the quality of the electronic components and the quality of the officers that were looking after it. So then I devised a system of automatic calibration so that they could calibrate at their leisure and then use their calibration as it were to [crosstalk]. And so that system was used from about 1941 to 1945 everywhere. So that was my first problem.

Sullivan: 03:37

So that's an example-- it's really more of procedures.

Hoyle: 03:39

Yeah. Well, then also they were-- anything that was basically insoluble used to land on my desk. And then I used to shove it under Bondi's desk. One problem that was so intractable that it led to disagreements both in the German general's staff and in the Allied general’s staff. And that was the problem of what you call chaff.

Sullivan: 04:09

Yeah, and whether it should be used.

Hoyle: 04:11

Whether it should be used or whether it should not be used with both sides. Well, it must have been about 1943 that this first got onto my desk. Was there any way in which we could-- in which we could distinguish aircraft among the chaff?

Sullivan: 04:27

Right.

Hoyle: 04:28

As it happened, we solved that problem more by chance than design. And the solution we used was the one that was employed in all post-war radar, both, I suppose Russian and Allied and American. It was our solution for a long time until it became possible to get power oscillators that would be sufficiently frequency stable. And the problem with a big power emitter--

Sullivan: 05:03

So this is continuing after an interruption.

Hoyle: 05:06

It was that we began when we were using high frequencies as they were then actually to say about 10-centimeter wavelength--

Sullivan: 05:16

Right.

Hoyle: 05:16

--to get very strange reports on the behavior of aircraft. And we decided we better look in detail at the way aircraft reflected the radar signal. And to do this, we had to look at individual pulses. Previously you had pulses and you just didn't look at what happened from pulse to pulse.

Sullivan: 05:40

Right.

Hoyle: 05:42

So we made our own equipment. At least Tommy Gold made it. And we then began to examine by photographic technique, individual pulses.

Sullivan: 05:54

I see.

Hoyle: 05:55

And we discovered that things can change from one pulse to the next in a most drastic way. And instantly, almost instantly, we saw from that that if we could remember the signal from one pulse to the next and make a subtraction, we would be left with something from an aircraft.

Sullivan: 06:17

Right.

Hoyle: 06:17

Whereas the chaff, the chaff will be steady.

Sullivan: 06:21

Right.

Hoyle: 06:22

And therefore, by subtraction technique, I mean, we could overcome the problem. And that was the method used for a very long time.

Sullivan: 06:30

Right, right.

Hoyle: 06:33

And this sprang out of a discovery that was just there for another purpose. And of course, it became instantly super secret and so forth. But at that time, there was no electronic means of remembering a signal for a 500th of a second. We had to use basically analog computers, converting it into sound and then back again from sound with crystals and so forth.

Sullivan: 06:57

I see, I see.

Hoyle: 06:58

So that was--

Sullivan: 07:00

So these are the kinds of things that you were working on.

Hoyle: 07:01

That's the kind of thing, yeah.

Sullivan: 07:02

Now let me ask you, when did you first become aware of radio astronomy, and did it influence anything you did during the War?

Hoyle: 07:10

It didn't influence anything, really, during the War. But I became aware of it probably earlier than either Ryle or Lovell. And that was because Edward Appleton, who was a sort of very senior scientist, realized that the work that was being done in different services was very uncorrelated. And so he formed what was called a Propagation Committee.

Sullivan: 07:33

I'm familiar with that Committee.

Hoyle: 07:34

Yeah. And so I was a member of it, and there were two admiralty members. I was one of them. And J.S. Hey was there.

Sullivan: 07:45

Yes.

Hoyle: 07:45

And so Hey told me all about his early things sort of over lunch [and so on?].

Sullivan: 07:49

Can you remember if you learned about them in 1942 when he had his first report, or was it only at the end of the War when he--?

Hoyle: 07:55

Oh, no, it was during the War. It was during the War--

Sullivan: 07:57

Well, [inaudible]--

Hoyle: 07:57

--right at the time he made them.

Sullivan: 07:59

Okay, so you remember hearing about it when he first made them in '42.

Hoyle: 08:03

He would tell me when he made his first discovery on the sun, he told me straight away. And when he first found a discrete source, he told me.

Sullivan: 08:11

And how did that strike you at that time as being very plausible or do you feel like it was--?

Hoyle: 08:17

I didn't think it. It never occurred to me there was anything wrong with what he was doing because I felt he was a trustworthy person. And this was one reason. In fact, we had all sorts of discussions as to how we would make antenna systems and so on if we got a chance. And Tommy Gold had the idea that subsequently became Arecibo.

Sullivan: 08:39

The spherical dish.

Hoyle: 08:40

Using the contour of the land. And we wonder whether that might be a possible way to do it. So all those things were going on before 1945. But after 1945, as I told you, we never had the opportunity because Cambridge was our university and Ratcliffe invited Ryle in there. So that may have been responsible, as I said, partly, for the tensions.

Sullivan: 09:08

So you would have liked to have gone on with radio astronomy research yourself?

Hoyle: 09:11

Absolutely. But it became a question that had we changed university, which we just didn't think of seriously at all. It might have been the problem of getting money. One needed a powerful backing. And basically Ratcliffe chose to import Ryle rather than use the people who were around. I couldn't have helped because I was a theoretician, as a mathematician, so it was Bondi, and so you could say the decision that Cambridge made was right. They would have had to rely on Gold almost entirely. But probably that started the tension between Gold and Ryle, I've always thought. Then when Gold left in '56.

Sullivan: 09:55

And Gold had his problems with Ratcliffe also in terms of the Cavendish. He finally left the Cavendish for a while.

Hoyle: 10:00

That's right. But the reason he had problems with Ratcliffe is because Ratcliffe brought in Ryle. He wouldn't have had the problems if they'd gone ahead. See, my connections with the Cavendish have been very close, but on the nuclear side. So Ratcliffe was sort of almost an outsider in the Cambridge before the War. He was just a very isolated small group. But after the War, it became a much more powerful.

Sullivan: 10:24

And the nuclear began to fade.

Hoyle: 10:25

And Ratcliffe would have seen me as one of the nuclear people. Oddly enough, I made great friends with Jack Ratcliffe in years afterwards when he was retired and we were members of the similar committee in so forth. But we weren't at that time.

Sullivan: 10:43

Well, tell me about the in the late 40s. I know you were interested in the sun. Of course, you wrote that small book about the sun, which had several, well, a whole chapter on the radio sun. So you obviously were following these things with an interest. I know that at the Kapitza Club [Note added 2024:  Pytor Kapitza was a Russian-born physicist who worked at the Cavendish but was detained in the USSR when he went back for a visit in the 1930s.] that there were lively conversations to do with these things. How did you see the field developing?

Hoyle: 11:05

I almost certainly in those years over weighted the importance of the sun. But there was a certain moment when I realized that what was going to happen on the radio side was going to parallel what had happened on the optical side. A lot of apparently interesting phenomena, but one didn't improve one's understanding of it very much. And that one had to step from the sun. I mean, it looked sensible to begin with, to start with the object that's nearest, the sun. And so I was very interested in the sort of '45, '46, '47 in the sun. But at some point, I must have seen that this was going to become more and more arid. And by 1950, I suppose I would begin to about the time of [Massey’s conference?], the Boyd conference in London, we were beginning to think extragalactically as the discusson showed.  [Ed. note added in 2024: In 1951 there was a conference held in London on “Dynamics of Ionized Media;”  editor of the unpublished proceedings was R.L.F. Boyd.]

Sullivan: 12:07

The discrete sources were-- well, but then of course they were--

Hoyle: 12:11

We made the spring theoretically to, Gold and I too. Gold was always more ready to speak at large conferences than I was. I think entirely due to the fact that from the age of about that age, my hearing wasn't good enough to take part in a large group.

Sullivan: 12:33

I see. So you were reluctant to--

Hoyle: 12:36

So I have to concentrate on listening to what's happening and you don't have-- if we're in a seminar room, you'll find I was interjecting and so on all the time, where it's easier to keep pace with what's going on, but in a big conference hall. So if you read the reports, you'll find that Tommy makes more of the interjections than I did but--

Sullivan: 13:00

But you did give a talk at that conference.

Hoyle: 13:02

I did give a talk at that conference, yeah.

Sullivan: 13:02

And you never made a lot of--

Hoyle: 13:05

[inaudible] problems, I think.

Sullivan: 13:07

Right. You never made a lot of comments about the radio stars but at one point you said I fully agree with Gold or something like that.

Hoyle: 13:13

Yeah. Well, we had talked about it. And we made the jump to thinking that things were [inaudible]. But in part, I must say, in my own mind, I would have to say that my discussions with Hey have played a role in that.

Sullivan: 13:30

I see.

Hoyle: 13:31

Because Hey was never-- he did notice that the Cygnus source that he found was along the plane of the galaxy. So one has a--

Sullivan: 13:43

It was confusing with that Cygnus X as it was called.

Hoyle: 13:45

Yeah, that's right.

Sullivan: 13:46

Ionized hydrogen complex.

Hoyle: 13:48

Yeah. So that was confused for a long time.

Sullivan: 13:52

But how did the discussions with Hey influence you?

Hoyle: 13:56

Well, I suppose in a new phenomenon, I like to bracket the possibilities. I do a wide grid of possibilities. And then as the observations come along, I sort of narrow the grid into a certain area. And at that time, we had a very wide grid and possibilities. And I suppose over the five years between Hey and [Massie’s] conference, I've been moving slowly towards the extragalactic part.

Sullivan: 14:28

But now I think from reading the proceedings of that conference, it seems that it was not so much that you, or at least Gold, believe they were extragalactic. He said we just can't rule that out.

Hoyle: 14:38

That's right. Because I said we had this grid of possibilities. But as soon as we began to see that there were two kinds of sources, it must have been about that time when we began to realize that there was an isotropic component.

Sullivan: 14:52

Right. The 1C survey of 50 stars, they were isotropic.

Hoyle: 14:55

As we said, that either means they're very close or they're very far. And I think I could reasonably claim that at that time I knew more about stars than the radio astronomers did, and I was very skeptical. It was the same argument I was having about quasars with Maarten Schmidt. Only four months I sat in Schmidt's office in December '62 and he and Sandage were claiming that the quasars were local like the radio stars. And I said, Maarten, I don't believe it. I think that they are very massive objects far out. And that has never been admitted, but you know there's a lot of ill feeling about the early days of the quasar. [Ed. note added in 2024:  Redshift of quasars was not known until February 1963.]

Sullivan: 15:38

Well, let's try to go along chronologically. We'll maybe hopefully get to that.

Hoyle: 15:43

Well, that’s another matter.

Sullivan: 15:44

But I think what-- is it correct that what bothered you mostly was the almost dogmatism in which they were stating that here is a population of radio stars and the extragalactic idea wasn't being considered at all by Ryle and -

Hoyle: 15:58

That's right. It's a matter of temperament. You have it in the quasar, I think now that the whole astronomical world believes that these things are at great distances, despite the fact that when you do our reasons for believing in big distances, classical reasons is the Hubble diagram. And when you put the quasars on the Hubble diagram, they do not indicate any distance effect. So I find it no difficulty in keeping an open mind. Whereas, it seems to be with most scientists, there's a religious drive in them to have a compulsion to believe something. Whereas, I don't have that at all. If you say, "Well, let's discuss this possibility and we'll discuss that possibility, or discuss this one." I find no difficulty in keeping an open mind about things.

Sullivan: 16:46

Now, let's just talk a little bit about the genesis of the steady-state theory. Was that at all influenced by the new radio astronomy?

Hoyle: 16:56

No, not at all.

Sullivan: 16:57

I've never heard that that it was.

Hoyle: 16:58

Not in my case anyway.

Sullivan: 16:59

Right. No, I've never heard that it was.

Hoyle: 17:01

No, the story there is that you heard what Hermann said. It was pretty accurate what he said. Three of us, I actually had a house deep in the countryside. And in winter, it became very inconvenient to, there were no buses or trains to get home. So I used to stay in college in the week and go home on the weekends. And one evening we went to the cinema and it must have been in '46, I think. And there was a picture that eventually became very famous called “The Dead of Night.” And it was a circular film. It was in four components and it later became-- it was one of the sleeper films that later became very famous, but it was re-entrant it went through a series of events and connected with its beginning. And when we got back to Bondi's rooms, Tommy said that maybe wouldn't it be interesting if the universe was like that? And anyway, we didn't take this seriously for a day or two. And actually, Hermann had been going through Robertson's article in the Reviews of Modern Physics. And I would frequently discuss the relativity with him. And so by this time, I'd understood the cosmological connections with general relativity and so forth. We were both very clear about it. And so we began to think about it rather seriously. But we saw pretty well that there had to be a creation phase involved. And frankly, they ducked away from this. They didn't like it. And I dropped it for almost a year until a number of events like-- I was talking about the origin of the elements. Incidentally, the elements didn't-- the work on chemical elements did not come from the cosmology. This is totally wrongly reported. It was an independent line of investigation, and you could say that cosmology to some extent came from the elements because I gave a talk to the Physical Society in Birmingham.

Sullivan: 19:13

You're referring to what Hermann Bondi said yesterday in his talk that--

Hoyle: 19:18

That it sprung out of [inaudible]. Many people believe that, but that's to set the arrow of causality the wrong way.

Sullivan: 19:24

I see. Please tell me about that. Yeah.

Hoyle: 19:26

Well, I had continued to sort of develop the ideas on elements and stars, and the Physical Society held a meeting in Birmingham. And my old supervisor, Rudolph Peierls, asked during the questions, he said-- Peierls believed that the elements came from neutron aggregates, huge neutron aggregates. So he was, to some extent, he was hostile to what I've said. And he, as a sort of curious criticism, he said, if you start asking where the elements came from, and you say they came from hydrogen, at some point--

Sullivan: 20:08

Could you say that again? What did Peierls say?

Hoyle: 20:12

He said, if you start imagining the elements came from hydrogen, at some point, you have to say, where does the hydrogen come from? You'll find in the recorded thing afterwards. It's in there in the publications of the Physics Society. And I wondered about this on the way home. I had a very cold drive in a very old car and I wondered about this. And this must have been November ‘47. And I wondered more and more and more. And through the following few weeks, we finished our teaching in Cambridge and I then got into the Christmas vacation. And it was during that Christmas vacation that I had the idea of copying a scalar field to gravity.

Sullivan: 21:05

I see.

Hoyle: 21:07

And at the - toward the end of January. I found what [Van Hall?] said in his lecture that as soon as you do that, an inflationary phase is inevitable. In other words, I got the [inaudible]. I got the solution. I wrote the thing up in February of '58. I gave a talk on it on the Cavendish on March the 1st. I still remember the day because both Dirac and Heisenberg were there. And Heisenberg subsequently reported when he got back to Germany, this idea of coupling a scalar to gravity was one of the more interesting things he'd heard during his six months in England. But that might be some personal aspect because Heisenberg had been invited by my college and I knew him pretty well.

Sullivan: 21:55

Right, right.

Hoyle: 21:56

So then, as Hermann said yesterday, I showed I actually showed them this solution. I showed them that before I sent it to a journal. I actually sent it to the Proceedings of the Physical Society. They returned it after about six weeks with a letter not rejecting it, but suggesting I sent it to the Royal Astronomical Society. But the problem was that the RAS had just printed one of my papers and it had taken nearly two years.  Not to any--

Sullivan: 22:35

They had tremendous delays that there was paper shortage.

Hoyle: 22:37

Yeah, that's right. And I thought, I then sent it to the Physical Review. And I got a reply again not rejecting it, but saying that it should be shortened to about half the length. And I was worried that it wasn't a very long paper. I was worried it would become meaningless. So then I sent it to the RAS. So owing to these sort of two events, I wasn't thinking about priority at all. Otherwise, I would have behaved differently. Meanwhile, Bondi and Gold had got back to it from their more philosophical point of view and written their paper and they sent it straight to the RAS. So owing to this sort of way the papers were dealt with. Theirs appeared just slightly ahead of mine. That's what happened. So the history of the priority in that theory is very complicated. The first concept that there might be that kind of thing came from Gold. They dropped it. We all dropped it. I returned to it, possibly due to Peierls's remark.

Sullivan: 23:37

But then when you returned to it, why did it not become a three-way thing at that point?

Hoyle: 23:46

Well, because they were still interested in cosmology and they were trying, as I remember, an electrical model. I seem to remember arguing with Bondi towards the end of December 47, in which he was saying he preferred an electrical, a kind of electrostatic effect, which subsequently did something rather like that with Littleton.

Sullivan: 24:14

Oh yes, that's right.

Hoyle: 24:15

So he had that sort of idea. And so if he said, "Oh yes, let's get down to this," then I think it would have happened that way. He's always said, and quite correctly, it was a bad mistake that we didn't all get together, but I don't think that was my fault. I think it was the circumstance, that they were trying a different possibility. And then when they saw my result, they saw it better to go that way.

Sullivan: 24:40

Right, right. And what was your attitude at that time? What was your attitude at that time that this was something that could solve the age problem primarily, or was it the intrinsic, the perfect cosmological principle being superior to the cosmological? What was the real attraction?

Hoyle: 25:01

Bondi made a lot of fuss about the age problem yesterday. But I think I can say with my hand on my heart, I've never been excited about that problem. I gladly accepted that it might solve the age problem. But again, I think I could reasonably say I knew enough about stellar structure not to feel that the universe just had to be older. And he mentioned Arthur Holmes. So I had no great faith in Hubble's value.

Sullivan: 25:35

So what was really the attraction for you? Was it just nice to have another model, or?

Hoyle: 25:41

The real attraction to me is what has now emerged from modern cosmology. They now say that, as I say, [Van Hoff?] said, if you couple a scalar field to gravity, the cytometric is that kind of steady solution is inevitable. This is understood now, but I found however I did it, and I tried several ways, I always got the same result. And so I stumbled on what is now known to the modern particle physicists. And I think that mathematical discovery was the thing that motivated me.

Sullivan: 26:22

But you lost the freedom of choice as to metric.

Hoyle: 26:25

Yes, that's right. That's right. It just drove you to that metric.

Sullivan: 26:31

And it wasn't anything to do with not liking the idea that there was a beginning at some time.

Hoyle: 26:38

Well, that has to be a component. Yes, I have never liked the idea of a beginning. So I should have done-- because I was reared in a sort of Christian background. I mean, my parents weren't religious, but it went on all around and all the kids went to church and so forth.

Sullivan: 27:11

Anglican?

Hoyle: 27:13

Yes, Anglican. And in fact, you could say the same with Bondi and Gold. I mean, it's Judaic Christian belief in an origin, but they weren't. So it was rather odd. But I think Greek culture, sort of, I think, played a role in this. I had more of a feeling, although I wasn't conscious of it, that I didn't like the idea of the one God sort of--

Sullivan: 27:47

You had more sympathy with the Greek kind of approach. You weren't influenced at all by Oriental?

Hoyle: 27:51

Yeah, I wasn't at that point influenced by Oriental things, but I think I had a sort of more of a feeling. Of course, I knew about the Greek mathematicians and so on, so I had an admiration for their culture. And I think I've always had a feeling that their religion was more likely to be correct. Not in a literal sense, but their - And you can see that the population at large divides into two groups on this matter. In the Western world, the idea of a sudden beginning is fairly popular, but there are people who just can't accept it. If I go to India, then nobody will accept it. I mean, they just don't like the concept at all.

Sullivan: 28:41

Let me ask more generally, as the debates swirled on through the '50s. Did you ever notice any component of belief that was of a non-scientific sort-- or a person's religion would seem to be determining somewhat the kinds of arguments they were making?

End tape 171A, Begin Tape 171B

Sullivan: 00:01

Here with Fred Hoyle on 22 May, '88.

Hoyle: 00:04

It's the dominant force in science today is the religious concept, I think.

Sullivan: 00:10

And it was in the '50s also, I mean?

Hoyle: 00:12

Oh, it's been there a long time, yes. The American scientists who are so concerned about these creationists in biology don't seem to realize that they themselves are creationists where the universe is concerned. They didn’t get to the stage of a whole huge number of Nobel laureates sending a petition to the Supreme Court about these chaps. But my feeling is a century from now, it will seem just as absurd to say the universe is 10 billion years old as it is to say that it's 5,000 years old. I think that that is the way it will come out. So I think we're a little bit more sophisticated than the creationists. But I think it's the same story. I think the human brain has a sort of trend towards creationism.

Sullivan: 01:16

A need for a beginning.

Hoyle: 01:17

Well, it stops further inquiry, doesn't it? And so--

Sullivan: 01:24

It solves the endless regression.

Hoyle: 01:27

It's what I was saying yesterday. Tommy's remark is the best. The universe is what it is because it was what it was. And that solves the problem. And that's the way to cope with it, whereas the alternative way, you have to examine every question. So I think it's quite correct what you say that I had a sort of built-in dislike of the finite beginning. But it wasn't very strong in those days. It was a sort of feeling. But it wasn't in any sense overriding. But certainly Bondi and I must have both felt that because we've been sparring from the time we read Robertson's article with all sorts of ideas for avoiding the singularity, the time singularity. And so we must have-- what we did not conceive of is the modern way of avoiding a literal singularity by means of a quantum state [inaudible].

Sullivan: 02:33

Yeah, yeah. Well, let me ask, at that stage when the theory was being developed in the late '40s, what did you see then as the main tests to distinguish--?

Hoyle: 02:50

Well, we saw that any phenomenon, if it is steady enough, will form a test just by looking back in time and seeing whether it's the same then.

Sullivan: 03:01

Which then did you think?

Hoyle: 03:03

So we saw the theory was immensely testable. And as Bondi's never ceased to emphasize quite correctly, that is the mark of a good theory, that it is instantly exposed to tests. But, again, it was Tommy who had the perception. He said, "Of course, this means that any wrong observation is going to look like a [disproved?] theory--" and so from the beginning, he was--

Sullivan: 03:31

He said that from the beginning.

Hoyle: 03:32

Right from the beginning.

Sullivan: 03:33

I see.

Hoyle: 03:34

Yeah, yeah, or almost the beginning.

Sullivan: 03:35

Prophetic.

Hoyle: 03:36

Almost the beginning. So he tried to-- the two people who went around preaching the testability of the theory were Herman and Dennis Sciama. I was a little bit more cautious because I had realized that what I said in my talk yesterday that a car can proceed steadily, but it doesn't mean that-- even though the cycles repeat themselves, it doesn't mean that within a cycle, things have to be steady. I pointed out that in 1949, against my colleagues, Bondi and Gold, that's where we differed. At least Bondi wanted everything so smooth that it was immensely testable. So I said it might not be so. If the Hubble time is the cycle time, things might be like the inflow and outflow of the gases in an engine in automobile. So I wasn't sold on this at all. Then when we got into the trouble with Ryle, I--

Sullivan: 04:45

Just before we get to that, did you see-- I mean, which tests did you think might be feasible? I mean, in the late 40s, were you thinking of galaxy counts, for instance?

Hoyle: 04:55

We discussed that a lot, but we decided it wasn't on. We were skeptical at a time when Hubble was optimistic that he could do it. Bondi talked about the galaxy counts and he was quite keen on them. But I felt that I had enough grasp of astronomical observations to realize it was very difficult. I knew about the immense difficulty of standardizing the plates at low flux values by photographic techniques. And so I wasn't altogether sold on that.

Sullivan: 05:29

What did you like as a test, or did you really not see anything at that time?

Hoyle: 05:33

Well, I think my views were more oriented towards star formation. I think I had already seen, from an early time, that the presence of the same elements in more distant galaxies, that kind of thing, will be more the way I was thinking. I was thinking about origin of elements and stars, and therefore if it's being ongoing, we ought to see the same elements, however far we see back in time. I think that I was thinking more astrophysically like that. When Sandage produced his q₀ values--

Sullivan: 06:19

This is now the late '50s. Right.

Hoyle: 06:21

Yeah, we're getting into the middle ‘50s. I was surprised that they were able to do it. I was always surprised that they were able to correct the magnitudes well enough to do it. And so that came as rather a surprise. Then there was a period when Albert Whitford thought he had a test on the reddening effect of gases--

Sullivan: 06:46

That's right. The Whitford-Stebbins effect, yes.

Hoyle: 06:49

--yes, that's right; Stebbins-Whitford effect, where he calibrated, I think, on one of the Andromeda satellites, something like that, and then looked back and said there was more reddening than there should be. That was interesting to me. And I had a lot of talk with Albert over there, but he finally decided his calibration was right. He told me that. So as it were, it looked quite good. The theory seemed to fit. It fitted the age questions. That fell into line. The Stebbins-Whitford effect disappeared and we seemed to see the same elements in the galaxies and so forth. So when Sandage came along, it was a bit of a surprise to me. So I said in Pasadena in the early '50s or whenever it was, "Well, if this holds up, it's wrong. The theory is wrong." And there I've never been entirely comfortable, as I said yesterday, about that q₀ business. But what actually happened is a girl called Elizabeth Scott.

Sullivan: 08:03

Yes. I know the name. Worked with Jersey Neyman.

Hoyle: 08:05

Yeah, that's right, Neyman's pupil. She came along and pointed out that Sandage might be moving the goalposts. Because as you go to greater distances, the brighter individuals may not be the same as the ones close by.

Sullivan: 08:23

This is now about 1960 or--

Hoyle: 08:26

We're moving. Well, it's a bit before that.

Sullivan: 08:28

A little bit before that. Okay.

Hoyle: 08:32

I should say, I would have said about 1957 or something.

Sullivan: 08:36

Well, before we get to the 2C and so forth itself, as we go from the period of 1950 to 1955, several radio surveys are coming out from Jodrell, from Australia, from Cambridge. How were your views on radio sources changing? Or were you just completely puzzled? As you began to get 10, 15 identifications and it was such a grab bag-

Hoyle: 09:03

Well, it never occurred-- it occurred to me that these were going to be of cosmological significance because when we began to get the sources, my first thought is we've got to find out what they are. And so I would never have had Ryle's concept of trying to do cosmology from things I didn't know about.

Sullivan: 09:23

But even with Cygnus A, it's such a high redshift, and yet the second strongest source in the sky, that didn't make you think that maybe these things are really far away?

Hoyle: 09:37

Oh yes, oh yes.

Sullivan: 09:38

But you'd want to have it established before you--

Hoyle: 09:40

Oh, I know. No doubt that many of the things might be far away. But it isn't my mentality to feel that you can find, you can settle a big question from something you don't know about. My feeling was that we've got to find more of them. So although I'm a theoretician, I don't believe anything that's observation unless it's really good, you see. I'm a great believer in good observation. And from the time I met Walter Baade in 1944, he had a very big effect because he's really the first great astronomical observer I've ever met. And Baade totally convinced me that you never believe anything unless it's really first class because he knew of so many mistakes. I mean, we talk about people like [von Neumann?] and so on. So I was never worried at all through the Ryle episode about the scientific issues because I knew the data just wasn't first class. And so I wasn't worried. But what I was worried about was the insistent public attacks.

Sullivan: 10:49

Yeah, yeah. But before we get to that, how did you know the data weren't good? Was that because of the comparison with Mills or even before then? Actually, I guess it's only a few months before that conflict came in, because just to remind you of the sequence, Ryle’s Halley lecture was in May 1955. Well, I should ask you, did you know about the results before that time? Did you have any idea that they were doing cosmology?

Hoyle: 11:20

No, no, no.

Sullivan: 11:21

Okay, so that was just a real surprise. So that was his Halley lecture. Then the Jodrell Bank IAU symposium on radio astronomy was in August. And that is where Pawsey presented Mills' very preliminary results.

Hoyle: 11:35

So I tend to say, well, it's my feeling. I'm always suspicious, for instance, of people who don't tell me what they're doing. I mean, you can see he talked to Bob Wilson. Well, he's been, I mean, I've known Bob since he was a student at Caltech, but we've always been friendly and he would tell me straight away what he was doing. And that's the way I understand [inaudible]. So I sort of worried that these things came out as a bolt from the blue. And then my colleagues such as Mills and Bolton told me that there were questions. You see, one of the things that I was suspicious about, and [it vitiated?] the 4C results in the early '60s, were the flux measurements that the receivers weren't [inaudible], and it is a clear thing that one can readily deduce that if you are making mistakes in the flux values, even if the mistakes are random, it has the effect of [steepening the curve?]. This was pointed out by Bolton. And so, as I say, I really wasn't too worried about the scientific aspects of the business. I was just mad that in my own university I was subject to these sort of attacks.

Sullivan: 13:00

Yeah, well, Peter Scheuer yesterday referred to the accusation that we had a secret method and that we wouldn't publish it. Is that something you felt at that time, referring to the P(D) method now?

Hoyle: 13:13

I would have said that it was more a matter that people didn't understand it. They felt that they were dredging something up out of nowhere, that it was a kind of rabbits down the conjurer's sleeve and that the data ought to be cleaner than that.

Sullivan: 13:34

If you have to resort to that kind of thing, then you're in trouble.

Hoyle: 13:38

You're in trouble. I think that's what was more the way people felt about it.

Sullivan: 13:43

But in retrospect, was that even fair? I mean, were they a bit ahead of their time in terms of the way one does simulations now? And indeed, you can get information in a statistical [crosstalk].

Hoyle: 13:57

Oh, yes. Yes, you can get it that way. It was clear that mathematically you could get it that way. But the question was, were they doing it right? And the other thing which worried me about Ryle was that he didn't seem to understand what a mathematician would understand, that if you have information which is, in some degree, suspect, but is interesting, that is okay to support a theory, but you can't disprove theories except by data that is unequivocal. There is a total difference. It's just that in mathematics, you cannot, if you've really studied accurate mathematics, you know perfectly well that you can't establish a negative except by the most rigorous reasoning. And he wasn't doing that. And he never did it to the end of his days. He never really produced it.

Sullivan: 14:56

That's very interesting. I've never thought of it that way, that he really had a negative result and one always has to work so much harder for a negative result. I've never thought of the reputation of a theory as being a negative result.

Hoyle: 15:07

I mean, if you get-- there's all sorts of things where you get a bit of positive information, it's not decisive, but that's fine. I mean, the other way around, it has to be absolutely cleaned up.

Sullivan: 15:19

Very interesting. Now, the Paris Symposium must have been a very interesting meeting. I've always looked upon it as sort of a watershed in the history of radio astronomy. It's, sort of, the last time that all the radio astronomers in the world could have a meeting called radio astronomy and could all be in the same room. And of course, it's especially interesting because of the conflicts over the source counts and so forth. And you were there. What is your recollection of that meeting?

Hoyle: 15:54

Well, I think the written record will show I took no part in it. I left it to the observers to -

Sullivan: 16:00

Oh, you mean in terms of making comments?

Hoyle: 16:02

Yeah.

Sullivan: 16:02

But you did give a summarizing lecture, and you also did give a talk on--

Hoyle: 16:07

Yeah, on--

Sullivan: 16:09

--radio source mechanisms, I believe.

Hoyle: 16:12

On angular diameters.

Sullivan: 16:13

Oh, that's right. You talked about the angular diameter test.

Hoyle: 16:15

[crosstalk] there's the test of a [crosstalk].

Sullivan: 16:17

But do you just have any recollections about the flavor of the meeting, and did it really--?

Hoyle: 16:25

Well, I was trying to-- I was trying to balance--

Sullivan: 16:27

[crosstalk] people arguing and really not listening to each other at all.

Hoyle: 16:30

I was trying to balance in my mind the comparative technical ability of the two groups.

Sullivan: 16:39

This is your first contact with the Australians, I believe.

Hoyle: 16:41

Oh, no.

Sullivan: 16:42

No?

Hoyle: 16:42

No. My first contact was when they threw John Bolton out of the Cavendish, which must have been in the early fifties.

Sullivan: 16:48

Oh, yes. Would you tell me that--

Hoyle: 16:50

I can't remember the exact year.

Sullivan: 16:52

Well, no, I can tell you it was May 1950 when he was--

Hoyle: 16:55

Well, I would've said--

Sullivan: 16:55

When he visited--

Hoyle: 16:56

I would've said--

Sullivan: 16:57

When he visited the Cavendish.

Hoyle: 16:57

I would've said '50.

Sullivan: 16:58

It was, yeah.

Hoyle: 16:59

I would've said '50. They allowed John into the Cavendish, I think, for a day or something, and then he was told by the Secretary to clear out. And I don't remember exactly-- he must have come to see me. That must have been it. And I invited him into dinner in John's. And then these things began to come out. And from then onwards, my contact with the Australians were fairly good because John had not yet fallen out with Bernard Mills, although the struggle between high frequency and low frequencies.

Sullivan: 17:37

Oh, yes, this is long before that.

Hoyle: 17:38

And so I think I was in pretty good contact with the Australians from that time. I would have remembered it as 1950. Yeah.

Sullivan: 17:47

Right, no, it was. Did you have any other contact with him before the Paris Symposium?

Hoyle: 17:53

Oh, well, you mentioned the Jodrell Bank meeting.

Sullivan: 17:54

Oh, the Jodrell Bank.

Hoyle: 17:55

[crosstalk].

Sullivan: 17:56

Well, no, he wasn't at that meeting, actually. Only Pawsey.

Hoyle: 17:57

It's Pawsey. It was Joe Pawsey, wasn't it? That's right. And Joe was a very mild sort of person. But for him, he was pretty acid when he compared their observation of Sagittarius with the Cambridge observation.

Sullivan: 18:15

Okay, well, back to the Paris Symposium. You say you were trying to gauge the technical skills, and were you able to come to any conclusions or, at that time?

Hoyle: 18:26

No, I came to the conclusion that either side might be right. And as I always do in these matters, I say the universe isn't there for our exploitation at all. I mean, the universe will have a final say, and I don't have any difficulty in waiting. I waited 30 years, but now I feel I know the answer. So I don't have any feelings at all about this.

Sullivan: 18:59

What did you make of the fact that despite more surveys and better positions, presumably, and so forth, you still were not getting dozens and dozens and dozens of optical identifications in the late '50s? The number had gone up by that time to maybe 30 or 40 identifications, half of which were normal galaxies anyway. What did you make of that? Do you think it was just the unreliability of the radio positions or--?

Hoyle: 19:26

Partly. It confirmed my feeling that the data really wasn't very good. One thing that was interesting in the Paris meeting and in the subsequent IAU was the feeling that, how difficult it will be to get identifications. I remember that. If we've been told that the number of identifications would run to many thousands, 30 years later, we'd all have been astonished. It was felt to be an almost impassable barrier at that time.

Sullivan: 20:09

Can you remember discussions with Baade or Minkowski?

Hoyle: 20:12

Oh, yes. Many, many.

Sullivan: 20:15

Yeah, can you tell me about what their attitudes--?

Hoyle: 20:18

Well, they felt the same way about the identifications. The sort of things we used to get excited about when Jennison found that Cygnus A was double. And he got the distance apart. Things like that and that the radio galaxies had this pattern of double sources. Those are the sort of details that whereas nowadays you wouldn't think maybe these were so important.

Sullivan: 20:44

That was clearly a big breakthrough.

Hoyle: 20:46

But it was that kind of kind of thing that used to occupy one's mind. After the Paris Symposium, I went to-- there was a meeting at IAU in Moscow and we filled in about a week by going to Leiden and Oort invited Tommy and I to Leiden and Bernie Mills. And we went out sailing together. So I had a long talk with Bernard at that time. But I thought Peter wasn't really fair. I never really felt that the Australians were anything other than very polite.

Sullivan: 21:21

Yeah, Peter Scheuer, you're saying in this talk yesterday.

Hoyle: 21:23

Yeah, he seemed to imply that the Australians attacked them viciously. I don't remember. I don't remember it that way. Even in private, Bernie Mills were still quite restrained in his remarks.

Sullivan: 21:39

But then Peter, he didn't say it yesterday, but last night he remarked to me, but then he was amazed a year after the Paris Symposium, there's an invitation from Pawsey and Mills to come join them for two years, which he then did. And he said Mills, you know, met him at the ship and took him out and had a beer. And he was amazed at that.

Hoyle: 21:58

But you see, I think what happened is that Bondi was very close to the thing when he called Ryle a paranoid, that he imbued his students with a feeling that they were under attack, that he felt it. And so they remained--

Sullivan: 22:13

Because they had an intense loyalty then.

Hoyle: 22:15

[inaudible] when they found it wasn't so. Yes. My feeling is the Australians attacked each other much more over the struggle and later over the design of optical telescopes than they ever attacked Ryle. So I wouldn't, but I mentioned going sailing with Oort and Bernie Mills. And naturally, we had these discussions and I remember Bernie as being very restrained.

Sullivan: 22:40

That's interesting. Although I would say that his 1957 paper, which I quoted briefly from yesterday at this meeting, certainly has some very strong statements. The Cambridge results are wrong. It's the kind of thing you don't normally write papers now.

Hoyle: 22:56

Well, they were wrong. They got minus three. And that was pretty bad. Mills, I remember in his first paper, didn't he get minus 1.8?

Sullivan: 23:06

In his first paper, yes.

Hoyle: 23:07

Yeah, and then he eventually came to 1.7 or something. Well, Bernie was very close. It was a good observation.

Sullivan: 23:14

But still, one normally couches in scientific papers results like this in milder language.

Hoyle: 23:22

If one of your one of your friends is being thrown out of the Cavendish, maybe you don't.

Sullivan: 23:28

Well, yeah. Well, let's just finish up on this and I'd like to spend a little time on the radio source mechanisms and then end up with the discovery of the microwave background and how you felt that affected cosmology, both for you and for the community as a whole. As time went on from 1955 into the early '60s, we began to have, of course, the 3C, then the 3CR, and then the 4C survey. Did you feel that things because we're improving at all or did you sort of give up on radio source counts? It was just getting more muddled as time went on.

Hoyle: 24:06

I then turned to the position that I've been in from the beginning, that the cycle time in the steady state theory might be of the order of the Hubble time. And in fact, Narlikar and I wrote a paper about '61 in which I think we took the irregularity time at about a third of the Hubble time. And we showed that in that kind of-- if the events were not smooth over a time of the order, I think, in fact, we took a tenth of the Hubble time. The distance that sticks in my mind is 300 megaparsecs. We showed that if we allowed the situation to be irregular on a scale of a tenth of a Hubble period, we could get slopes as steep as minus two. And we proved this from computer simulation. And so Monte Carlo techniques, the paper in the Monthly Notices. So I didn't really worry about those steep slopes because to me it seemed all it implied is a certain degree of irregularity in the engine. And so I was never worried.

Sullivan: 25:16

Now what about the possibility of--

Hoyle: 25:18

[crosstalk]--

Sullivan: 25:18

Yes.

Hoyle: 25:19

What worried me more than Ryle was the fact that Bondi and Sciama both have propagandized so much for the completely smooth interpretation of the theory that it was very difficult to get people to realize that, as I said, the fuel cycle of an engine takes a whole cycle of time before it repeats itself. And so--

Sullivan: 25:41

This cycle idea on a large scale did not appeal to them? They felt that that was degrading the theory somewhat and losing some of its attractiveness?

Hoyle: 25:50

Well, that's what people said. But to me, logically, it made no difference. So I was a bit annoyed that people wouldn't listen to the logic. I only get annoyed when people want to, sort of, ignore the logic. And the logic was that you could perfectly well have this system of cosmology where events-- when I look at the world, I don't see everything as smooth. There are all sorts of turbulence in the air and so on. And so I expect it will be the same in cosmology and you try the simplest thing first, and if the simplest thing doesn't work, then you try the next simplest thing. And so Narlikar and I, as I remember, we didn't go to the full extent. We went to about a tenth of it and we showed that already if it was regular, it was a sort of time turbulence on the scale of a tenth of the Hubble time that we could get the steep slope. We got all slopes down from about 1.3 to 2 or something like that.

Sullivan: 26:57

There was also quite a bit of discussion about the possibility of a local hole in the lack of the bright [crosstalk].

Hoyle: 27:05

Peter wasn't correct yesterday when he said the ground shifted on the steep counts so that it was a question of whether where you set the levels, that it could be explained with a deficiency of only about 50 sources. That only occurred in the late ‘60s. I give a talk at the Bakerian Lecture at the Royal Society in '68, I think it was, in which I pointed out that it may not be the slope that's rising steep, it might just be the bottom end that's a little low because about 50 sources were missing so that we couldn't really make too much of a song and dance over 50 sources.

Sullivan: 27:53

Speaking of Bakarian Lectures, you reminded me of Ryle's 1958 lecture. Did you hear that per chance? His Bakarian Lecture in 1958, in which the Cambridge group always considers that as a masterpiece,  a logical demonstration using what identifications there were, using the source counts, that these things really were extragalactic. At some stage, of course, you must have also been convinced that they were extragalactic, that the situation improved from 1955. What was it that gradually made you be willing to accept that these things really were extragalactic and therefore you should pay attention to the source counts.

Hoyle: 28:37

Well, I suspect they are extragalactic long ahead of Ryle.

Sullivan: 28:42

Well, what I meant was that you were pretty convinced that they were extragalactic. Was there any [crosstalk]--?

Hoyle: 28:49

Oh, the Baade-Smith determination of Cygnus A, that settled it.

Sullivan: 28:57

Well, no, what I meant is, oh, are you saying that when 2C came out, you had no doubts they were extragalactic, but it was that they were not understood that bothered you. Nothing about their luminosity function, for instance, was known in this kind of thing.

Hoyle: 29:15

I know, no doubt.

Sullivan: 29:16

Okay, I see. When you said that they weren't understood at all, I thought you meant it was still an open question.

Hoyle: 29:23

No, not at all. We knew the isotopic component was extragalactic. But we didn't know where they were.

Sullivan: 29:30

Right. And you didn't know the luminosity function, etc, etc. Okay. I misunderstood.

Hoyle: 29:34

I mean, they might have been a local cloud. I mean, within the nearest 10 megaparsecs for all we knew. But when Baade discovered the redshift of 17,000 kilometers a second, he began to suspect that they were much further out. And you could say that there are going to be eventual use for cosmology, but my feeling, I didn't suspect an attack from that quarter at all because I felt we were so far away from knowing enough about them to be-- as I say, I've always had the attitude that I only believe data that's unequivocal. And it would never have occurred to me that you would try to disprove a theory by data that was as vague as that. So I had no such thought at all. Besides which, of course, by this time, I knew Edwin Hubble extremely well because whenever I was in Pasadena, we always used to go, every Sunday morning we walked together. And so I knew that by now the inside story of all the difficulty of counting galaxies. And it seemed to me that you know what a galaxy is and you can count it far more, many more of them than radio sources. So it would never have occurred to me in 1955 that one would have this kind of thing at all.

Sullivan: 30:59

Interesting. Let me just ask, I've never looked in Hubble's papers or anything. Do you have any recollections of what his attitude was towards this new radio astronomy? Because he died in '53, I believe it was, but--

Hoyle: 31:10

No, about 1960, '59 [inaudible].

Sullivan: 31:14

No, no, it was '53. '53.

Hoyle: 31:18

Was it?

Sullivan: 31:20

Yeah. The same year he got the gold medal of the RAS, but did you have any recollections about what he thought of radio astronomy? I'd just be curious.

Hoyle: 31:29

I don't think we ever discussed it.

Sullivan: 31:31

Probably not. Another question. Did you ever carry on discussions through the '50s with any of Ryle's students, or was the whole group?

Hoyle: 31:43

That was forbidden.

Sullivan: 31:44

That was forbidden.

Hoyle: 31:45

I can tell you one event from the '60s and show us the way it was. I had somebody visit me because a Russian astronomer had been jailed on what was said to be very flimsy ground. A chap came to me, to see me, a Dutchman and said, was there any way I could do anything for him? It was felt that if I could approach Ambartsumian, that they knew [crosstalk]--

Sullivan: 32:21

[inaudible] in the Communist Party, yeah.

Hoyle: 32:23

--that something might be done for him. It was pretty much that he hadn't really done anything. He translated a few Western books. It's one of these cases. And some of the literature that the Dutchman brought me was in Russian. And I wanted to get a translation of them. And I knew that Malcolm Longair spoke Russian or knew enough Russian. So I rang up Malcolm and said, "Will you come, can we meet?" And Longair-

Sullivan: 32:56

He was a graduate student at that stage in the late ‘60s or something.

Hoyle: 32:58

Longair wouldn't come until the department had shut after 5 o'clock because he didn't care to tell Ryle he was coming to see me.

Sullivan: 33:07

I see. Amazing.

Hoyle: 33:10

And Ryle wouldn't add his name to the letter I wrote to Ambartsumian. I tried to get [inaudible]. So I sort of kind of despised him. So relations really were very bad and they continued to grow worse. I think there's only one person, and yet I feel somehow that it was just unfortunate that I inherited the enmity between Gold and Ryle. But I don't think there's any way in which it could have been different. As someone put it to put it to me, Ryle's real ambition was to be a theoretician. And so he could never let it go. Well, you just have to take his luck and how it turns out, I suppose.

Sullivan: 34:14

The quasars, I didn't realize that you had been in Pasadena during the year or two in which one had these spectra and couldn't do anything with them. Can you tell me?

Hoyle: 34:25

I was there at the time.

Sullivan: 34:26

Yeah, can you tell me about your recollection?

Hoyle: 34:29

All I know is that Greenstein had the spectrum of 3C48, but I didn't know at that time that Sandage is part of it. Otherwise, if I'd gone to see Allan, I might have got a chance. But Greenstein wouldn't let any of us look at it. So that was the problem. And he was subsequently punished because if he had, perhaps we would have gotten the redshift--

Sullivan: 34:51

Before Schmidt.

Hoyle: 34:51

But John Bolton, whether John is romancing or not, I don't know. He has always told me since that he was there. And because he was in the same building, he managed to get a look at the spectrum. And he had always claimed that he had proposed that it be looked at as a large redshift object.

Sullivan: 35:13

And it was dismissed as being unreasonable or--

Hoyle: 35:16

I don't know. But what was never done in any seminar was to say, this is a very interesting spectrum to show us, and write the wavelengths down. Otherwise, it's almost certain that we would have got the community generally.

Sullivan: 35:30

With 10 or 20 people playing--

Hoyle: 35:31

But Greenstein sat on it, feeling that as long as he kept the data in his desk, he might see what it meant. And he was subsequently punished for this. But the story then is that Bolton had always wanted to build a high frequency-- What actually happened was when Caltech wanted to start radio astronomy, Lee DuBridge, who knew Taffy Bowen very well said, "Who should I appoint?" And Taffy went to John and said, "Well, here's your chance. You believe in high frequency. If you want the job, it's there." And that's why Owens Valley went to high frequency straight away. That's the reason for that. And anyway, when Taffy had finished the 210-foot at Parkes, he wanted somebody to run it. And so he asked John to come back to do it. And so John returned to Australia, but he had all these things about 3C48 in his head. And when Cyril Hazzard, Cyril was those vague sort of individuals who shifted from one appointment to another. And he eventually wound up in Harry Messel’s department.

Sullivan: 36:47

Right. I have talked to him about this.

Hoyle: 36:50

Yes. Well, Cyril knew that 3C273 was going behind the moon and that it only does it once every 18 years, I suppose. And he applied for time. I mean, if Cyril hadn't been such a vague individual, he would have realized that the ill feeling between Messel and Bowen was so great that he wasn't going to get it. So his application went in and the person who prevented it being thrown out was John Bolton. John said to Taffy, "This is important. You really must give him the time." And so they put the chap, his name begins with S, to work with.

Sullivan: 37:39

Shimmins.

Hoyle: 37:40

Shimmins. That's right. They put Shimmins in to work with Cyril. And you should hear Ed Ney. Ed Ney was there at the time, to tell the story about how he thought he was doing important work helping Hanbury Brown at Narrabrai while all the time Cyril was down at Parkes doing the really important thing in his vague sort of work. But anyway, Cyril got the position. John realized that if he left the matter with Cyril, nothing would be done about it. Well, at least there would be publication eventually in a vague sort of way. But that it was very important. And now this is the key thing in the history of the discovery of quasars was who John wrote and gave the position away to because the position was so definite that you could be sure of the object. And so the history of the discovery of quasars now turns on who John sent that letter to. Well, he could have sent it to Allan Sandage. He could have sent it to Margaret Burbidge. He chose to send it to Maarten Schmidt. And that Caltech, that part of the story, there's no way Maarten Schmidt would have made the discovery if he hadn’t got that letter.

Sullivan: 38:54

No, I mean, I've always considered it as a co-discovery. I mean, it depends on how you define discovery.

Hoyle: 38:58

Yeah, but if you [crosstalk]--

Sullivan: 38:59

Oh, I agree, I agree. It's a Caltech discovery.

Hoyle: 39:02

Oh, well you know it, that's all right. Yeah, yeah, that's it.

Sullivan: 39:05

Oh no, I know about this. I think it was actually Cyril that sent the letter though, but undoubtedly it was John told him who to send it to.  [Ed. note added in 2004: It was Bolton, not Hazard, who sent the letter to Schmidt.  The letter was actually about another radio source, and 3C 273 was only tagged on to the end.]

Hoyle: 39:10

It might have been. Yeah. Yeah. He might have [crosstalk]. Yeah. Yes. Yeah.

Sullivan: 39:14

But why did John choose Maarten Schmidt?

Hoyle: 39:18

Well, because they've been in the same department.

Sullivan: 39:20

Well, but I mean, as opposed to Greenstein.

Hoyle: 39:23

Well, I think it's because Greenstein hadn't really shown he'd been so secretive about the 3C48 that John felt that he was secretive about this too.

Sullivan: 39:37

Right. But now what 3C, let's see, I'm trying to think now. So Bolton would have been definitely thinking that this could be another one of these strange stars.

Hoyle: 39:52

That's right. Yes, yes, sure. Sure. I don't think John had the concept that it might be the giveaway it finally was in having Balmer series easily identifiable.

Sullivan: 40:02

Right giveaway, I think maybe two easier term. I mean,

Hoyle: 40:08

Well, when you've got three lines of the Balmer series, it's hardly avoidable.

Sullivan: 40:13

And of course, the redshift wasn't that high. Also, that helped a lot. But now, okay, so the quasars break onto the scene and-- or do you know more about the Caltech story? Were you there when that discovery was made or shortly thereafter?

Hoyle: 40:28

I wasn't actually there. I was traveling back from Australia and I passed through Pasadena and Willy Fowler and I had generalized a concept of Geoff Burbidges. Geoff had kind of claimed that the only thing that would give the energy of the radio sources were a whole series of supernova explosions. But he never explained how these were together. So Willy and I started to think about massive objects, really big masses. And we started with nuclear energy, but toward the end of that year, which would be '62, I realized that nuclear energy wouldn't do it. At least we both realized nuclear energy wouldn't do it. The reason I went to Pasadena was to finalize a letter to Nature with Willy in which we proposed that it was gravitation, [inaudible] strong gravitational gravity source.

Sullivan: 41:22

Right. And that came out in '62, I believe.

Hoyle: 41:24

That must have been January Nature, probably '63.

Sullivan: 41:27

'63. Okay.

Hoyle: 41:28

Yeah. And I went-- Maarten Schmidt and Allan Sandage were giving a joint paper in New York on the nature of these objects. Of the, I suppose they were--

Sullivan: 41:50

Was this a AAS meeting, I believe, or was it the New York Academy of Sciences?

Hoyle: 41:58

Yes. Now what would they call them at that time? They would be radio sources, compact radio sources. They would be looking at them. They wouldn't have got the spectrum, but it was a sort of-- by now it was recognized that there was a class of unresolved--

Sullivan: 42:15

That's right. You had many doubles--

Hoyle: 42:16

--unresolved sources, which started with Hanbury Brown with the Brown Palmer stuff Jodrell.

Sullivan: 42:22

And it was clear the spectrum was different for these compact sources.

Hoyle: 42:26

So they were giving a paper and they’d more or less gone back to the early sort of radio source idea of local stars. And I don't think that was ever published. I think they suppressed what they said.

Sullivan: 42:41

That's right. That's correct. It was not published, right.

Hoyle: 42:45

Yes, that's right. They suppressed it, smartly.

Sullivan: 42:47

Were you at that meeting?

Hoyle: 42:49

No, but I talked about the paper that they were going to give with Maarten in his office on the first floor [2024 note: second floor] floor of Robinson. And I said to Maarten, "Do you think there's any possibility that what you're really seeing are these kind of objects that Willy and I have been investigating?" And he told me in his-- in the typical Dutch fashion that he didn't think there was much possibility of that. So that was the way the story ended for me personally. I always felt that conversation ought to be mentioned. But the next thing I heard, and I heard it one day ahead of doing a program for the BBC. I got a letter from Willy, which was about some nuclear thing. But at the bottom, he just wrote, "Whoopee, they found our object."

Sullivan: 00:02

Well, on 22 May '88.

Hoyle: 00:06

So that was the discovery as far as I was concerned. I heard about it, must have heard about it the very first moment it was announced because Willy wrote to me on the instant and told me that things have been found.

Sullivan: 00:20

Now as you begin to have 5, 10, 20 of these quasi-stellar objects as they became called, what did you make of them in that first year?

Hoyle: 00:39

I didn't make of them very much, and I think that it's at this point you have to give Maarten Schmidt full credit that he drove through the investigation of those first objects out to large redshifts. I think it was 3C9. Was it something?

Sullivan: 00:57

I think that's right, yes.

Hoyle: 00:58

Yes, with a big redshift. He drove that smartly through with remarkable speed once the thing was there so that by the time I attended a seminar that Schmidt gave in Caltech, maybe, as you said, about the end of the next year, I was amazed at how they managed to get spectra and so on and follow it up. I think that in a way was Schmidt's following up of the discovery was really more remarkable than the discovery itself. That was very, very good. It was quite clear. I had no thought at all at that time that the redshifts might not be cosmological, no thought at all. To me, it was clear that they were. And it was also beginning to be clear that I realized this was a much more direct threat to the steady state cosmology than I'd ever felt the counting of radio sources was. The riches were big and so there was a means of testing.

Hoyle: 02:11

My idea, and I think of other people at the time, was that the redshifts were so big when I heard about two, that now it would be possible to carry out Allan Sandage's test, what we now call the q₀ test, that it would be very quick to settle the whole matter and see what the curvature factor was. And so I had a feeling that now the matter was going to be settled. And so I think by the time there had been 20, I had this feeling that we're on the verge now of-- and that probably the theory was going to be wrong. That was the way I felt about it in '64. I'd also--

Sullivan: 03:01

Why did you feel the theory was going to be wrong?

Hoyle: 03:03

Well, I had, together with the chap called Taylor in England, I recovered some of Gamow's early results on the helium production, the stuff that Bob Wagoner, Willy Fowler, and I generalized later. I'd done that in '64. I'd had a conversation that in retrospect was very unfortunate that we didn't make one more move with Bob Dicke. We were both at a summer school at Varena up on Lake Como. Bob told me that they were preparing to do an experiment at Princeton, the experiment that Penzias and Bob Wilson that we’ve just been talking about actually did. And he told me-- I said, "Well, what's a temperature?"

Sullivan: 03:54

No, no, let me get this straight. Dicke told you that his own group was preparing to do an experiment.

Hoyle: 03:58

Yeah, that's right.

Sullivan: 04:00

He didn't know about Penzias and Wilson.

Hoyle: 04:03

So I said, what temperature? And he said about 10 degrees. And I said, "Well, that won't do, Bob." He said, "Why not?" I said, because "Andrew McKellar got the bands of CH and CN around 1940, and it's an excitation temperature of three degrees."

Sullivan: 04:21

So you immediately pointed that out to him?

Hoyle: 04:22

Yeah. I pointed this out to George Gamow that his temperature was too high. And if only he had said, “Well, it is three degrees,” we'd have had it, he needn’t have done his experiment. That is the worst mistake of my life, I tell you. Bob and I, between us, we had it, because he was convinced it existed and I knew the temperature.

Sullivan: 04:42

That's amazing.

Hoyle: 04:43

Yeah, and we didn't put it together. We could have written our letter in Nature.

Sullivan: 04:48

But you had pointed this out to Gamow.

Hoyle: 04:50

Yes.

Sullivan: 04:51

At what time?

Hoyle: 04:52

'55.

Sullivan: 04:54

Amazing. Now something that has always puzzled me. I mean, I'd like to hear your opinion on it and maybe you talked to some of the principals is that in the late ‘40s, one of course had this, I always like to think of it sort of as intimation. I mean, they never come out in any of the papers and say, here's a temperature, we should look for it. There's nothing like that. But it's in there. It's in there in the equations. No one acted on this as microwave technology improved through the '50s and radio astronomy went to higher- Why was this?

Hoyle: 05:26

Well, I think I didn't do anything because I was conscious of this feature of three degrees being the highest possibility. And that looked, I suppose, to the technology too difficult.

Sullivan: 05:37

It would have been very difficult. Of course, Dicke was precisely the man to do it, even in the early '50s.

Hoyle: 05:44

Yes. I think he said 10 degrees because he felt he could do 10 degrees. And so you never go around, as it were, sort of hammering into people's heads that when they're willing to do some work, that it might be useless. I think that that has a certain part to play. Then, of course, the Penzias and Wilson. And I'd done the helium calculations. I personally did them, and it was a question of checking all the details. And Taylor came in with me and he had more time than I had. And he checked the details and we published this in Nature. At that time, I hadn't realized that one of Gamow's students had pretty well got it right. Gamow's original publication had done the baited theory wrong. That's why I did it repeatedly. I realized he hadn't done it right.

Sullivan: 06:42

And who is that student?

Hoyle: 06:44

Taylor.

Sullivan: 06:45

No, who is that student, Gamow's--?

Hoyle: 06:47

It's Alpher, Follin, and Herman, but I wasn't aware of that paper at that time. They did it the same way that we did it.

Sullivan: 06:57

And so this was causing your confidence in steady state to shake a bit.

Hoyle: 07:04

Then the microwaves were discovered. And just on that discovery, before I actually saw the technical report, I was asked to give the public lecture at the British Association, and it was given in the Senate House in Cambridge, and it was afterwards printed in Nature. And what I said was that there'd been a whole set of converging lines of evidence against the theory and that it will be settled very shortly because the redshifts of the quasars were so large that we would see on the Hubble diagram very clearly what the truth was. And that is printed in Nature.

Sullivan: 07:53

Right. Were you considering the microwave background as a setback at that stage?

Hoyle: 07:57

Oh, yes. Yes. Oh yes, certainly. Well, so I was hovering, then, on the position that Dennis Sciama. Dennis got out very fast, as he said. He recanted. I was on the point of it in that lecture and would have done so if, when the quasars were-- so the number that were detected-- and they were detected very quickly at that stage, so that within a year, it was adequate to take a look at it. But by the end of the year, we had about 50, by the end of '66, something like that. Burbidge and I put them on a redshift magnitude diagram and we found it was a scatter, scatter diagram. So I looked at this and thought, "Well, this is amazing." We published it in Nature. This is amazing. Here I am on the point of saying, "That's the end of the theory," and I'm looking for this as the final chopper, as it were. And what I get is something that's completely indefinite. So Burbidge and I have kept a watch on this as the number of redshifts or quasars has gone from that original 50 to 3,000 [dot?], and it's remained exactly the same. There's a new survey that [Kron?] talked about on Friday. It's just the same as a scatter diagram.

Sullivan: 09:33

Yeah. So in some sense, that was sort of the low point in your confidence in steady state, a minimum, at that stage.

Hoyle: 09:41

But I still didn't have any great confidence in it as it is shown by the fact that following it in '66, together with Fowler and Wagner, we did the helium lithium,--

Sullivan: 09:56

That's right.

Hoyle: 09:56

--yeah, thing, so--

Sullivan: 09:58

That's right. You spent half the time on that, yes.

Hoyle: 09:59

That's right. So I was beginning to think in terms of the Big Bang cosmology. That favored it.

Sullivan: 10:08

I'd be interested in your views on--

Hoyle: 10:10

So I told you, I have no difficulty in keeping an open mind. So I just kept my mind open. And my mind has been open sort of all through the past 20 years, and I haven't known which way to go.

Sullivan: 10:31

But you like playing the role of provocateur also. I mean, obviously--

Hoyle: 10:35

Well--

Sullivan: 10:36

--sort of a contrarian philosophy.

Hoyle: 10:38

It's just that I had to slave so much when I was a student. Although my instincts were towards physics, the subject I read at the University was Mathematics, and I had to slave so much over accurate proofs that I really don't finally believe anything until I've got an accurate proof. And so, you know, a mathematician-- if some other fellow comes along and says, "I proved it," and you can see he hasn't, you point it out. There are all sorts of people proving Fermat's last theorem, but you're not an agent provocateur, because you show him where his mistake is. So I feel that the logic is lacking in physics, particularly in astronomy. And so I've always acted that way,--

Sullivan: 11:26

That's interesting, your mathematical beginnings.

Hoyle: 11:27

--that they're not properly trained sort of logic.

Sullivan: 11:32

Interesting comment. I'd be interested in your opinion about why the astronomical and physical community as a whole, after all this wrangling over steady state versus evolving cosmology, pretty much within a year, reached a consensus. The microwave background. Was it that they were tired of the wrangling, they wanted to grab on something? Or was it that it really was such a beautiful prediction that it was textbook science in the sense that the-- or was it that people feel uncomfortable, as you were saying earlier, unless they're all agreeing on something that they [inaudible].

Hoyle: 12:18

It had all the advantages. It satisfied the facts, which were in a certain sense predictive, it was culturally acceptable. And there is a natural tendency in a subject that's as difficult as astronomy for people to tend to herd together in their beliefs, just as fish do in the sea when there are predators around you. I mean, in a difficult situation, people are more like to become [unclear] more than the people that are in difficult subjects. In subjects where you have more control, you get wider ranges of opinion. But in biology, in astronomy, where the subject is so far-ranging, you'll find people converge all on the same beliefs, more or less as a protective phenomenon.

Sullivan: 13:06

It's almost opposite to what it should be.

Hoyle: 13:07

[crosstalk] it's opposite to what they should be. To protect their sanity. So this seemed to be the way it went. And so I, as I say, kept an open mind over the past 20 years. I've just stood back and watched, and I know perfectly well throughout the history of science that when you get the right theory, correct theory, the progress is very rapid always, but it hasn't been. I’d watched the redshift magnitude diagram for the quasars and seen that there's something funny about it, which isn't very well understood. I mean, there's no distance indicator in there at all. So if you say there's evolution, the evolution that there's been is precisely that which is required to conceal the distance. So I regard that as funny. I also noticed that if you talk to a young person today and say, "What is the best evidence for your beliefs?" The best evidence they recall is that evidence that we had in 1966. They wouldn't have anything later to offer. And I regard that as suspicious too. So that's my position.

Hoyle: 14:20

But I have never been willing to become active again in cosmology until I could see how to deal with the microwave background. And where I'm quite pleased now is I see having reviewed all the possibilities that there is one that will do it, and that it is quite testable. We can get at it[unclear]. I don't believe that within a year there could be really very much doubt about this because we have the far infrared observations that we didn't have. Basically, when Frank Low discovered sources in the far infrared, he opened out a new field and he knew that. And when he did it, people wouldn't believe him because we couldn't believe there could be particles.

Sullivan: 15:05

So large to radiate efficiency.

Hoyle: 15:07

To have such a large radiating efficiency in the far infrared. So this really told us that there was a particle there. And so now we're faced with a situation that we can go to 200 microns, 300 microns. And if you believe these people who've worked in the Antarctic, you can go to two millimeters. That's through the maximum of the microwave background. It's a question, now, if you believe the Crab Nebulae, you can go to 10 centimeters with the particles. And so it's the kind of situation I like that we can do something, I'm not involved in speculation. I've been calculating the infrared sources. Now, using these kind of particles, I can calculate their structures and do a lot of mathematics on it. And that's the sort of position I like to be in.

Sullivan: 16:01

Well, can I take you back to the '50s again for a topic that we've only briefly mentioned on, but you wrote several papers on it, and that was the radio source mechanisms? What was the physics that was producing? Of course, this was a puzzle. And to me, the central question--

Hoyle: 16:16

That occupied my mind far more than these questions you've been raising.

Sullivan: 16:19

-in the history is why did it take so long for the ideas of synchrotron radiation that Ginzburg and his students, and then a couple years later Shklovsky, were so strongly putting forth in the Soviet Union from 1951 onwards to become accepted in the West, especially considering that the original suggestion of synchrotron in an astronomical context, as you know, were two papers in Phys. Rev.

Hoyle: 16:45

Was it Schwinger?

Sullivan: 16:47

Well, not in the astronomical context. Schwinger worked out--

Hoyle: 16:53

There was a paper was it in Phys. Rev. by--

Sullivan: 16:58

Alfvén and Herlofson?

Hoyle: 16:59

That was just done for stars, wasn't it?

Sullivan: 17:01

Alfvén and Herlofson were interested in it for radio stars, and of course it fit in with Alfvén's ideas of a magnetic field being important in a solar system size. A couple months later, Kiepenheuer suggested the synchrotron to explain the galactic background and worked it out in a brief paper in Phys. Rev. Letters. The same year, 1950. And then this just died there, except that Hutchinson in the Cavendish did a paper, and there was one or two other things, but no one picked this up.

Hoyle: 17:38

It was such that I turned to this in '53 in total ignorance of all the other things. And there was a conference in Washington in early, I think January '54.

Sullivan: 17:53

That's right, the radio astronomy conference.

Hoyle: 17:54

And if you read that, I gave a paper on doing the thing by synchrotron. It was all plasma. They attacked me furiously. Alfvén was there, and he stood up and said, but I wrote a paper with, he kind of defended his priority from 1950. And I looked it up and sure enough it was there. He got the same formula as I had, but it was for stars. That's right. It wasn't for distribution. And when I printed this as a note in Nature in January '54, and because Alfvén had pointed this, I referenced it.

Sullivan: 18:35

Well, that paper I'll have to check. Was this in JGR? It was in JGR in the proceedings of this meeting, so I suspect it was.

Hoyle: 18:42

Yeah, but it's also in Nature.

Sullivan: 18:43

It's also in Nature, okay.

Hoyle: 18:44

Now Ginzburg in his book on cosmic rays, he references '53 for the first Russian publication.

Sullivan: 18:51

Well, no, it's '51. It really is.

Hoyle: 18:54

Well, I don't know whether you've got it, but Ginzburg's reference in his book is '53. So if that's the right reference, because he says basically that the priority was that the claims that he was before that were wrong. And his paper was the first in '53. And I don't know whether that's true. But the real reason is that Russian papers weren't translated. I knew nothing about them whatsoever, that we had no translation of them whatsoever. And it was the plasma physics lobby that overwhelmed them.

Sullivan: 19:27

And the Russians weren't coming to the meetings either at that stage.

Hoyle: 19:29

No. No. So that's the reason. We didn't know what they'd done.

Sullivan: 19:34

And these two Phys. Rev. Letters in 1950 just fell on stone.

Hoyle: 19:40

That's right, because of the plasma. And if you read that Washington conference, I was practically plowed under because I was a lone voice.

Sullivan: 19:49

That's right.

Hoyle: 19:51

I was quite annoyed about this because it was right, and I had to face the static at that. And I lost, as soon as I realized the Russians had done it. Of course, I had no priority, so I never, never- But I spent two or three years of really hard work to get to that position myself, sort of investigating conductivity properties and so forth.

Sullivan: 20:17

And your main motivation to be looking at that was the radio astronomy problem?

Hoyle: 20:20

Yes.

Sullivan: 20:21

I see. Could you just sort of outline what you did during those two or three years?

Hoyle: 20:27

Well, it was really the technical question of what currents could flow in magnetic fields, and understanding the conductivity problems. This I spoke about at some length. That's the sort of thing that was in our mind. And to some extent, this obscured the synchrotron business. It was the technical problem of how the currents flow because the problem really is that you have a magnetic field, and that inhibits currents from flying across it. You can fly along with a magnetic field without any problems. So there are all sorts of things as to whether you could have cosmic systems where the currents were always along the direction of the magnetic fields and so one got snarled up in that kind of problem.

Sullivan: 21:20

The standard assumption today of a virtually infinite conductivity was not.

Hoyle: 21:24

Well, nowadays nobody bothers about the conductivity problem, but we did. So it was trying to understand this whole matter that occupied us. At the time of the Massey conference, the Boyd Conference in London, that seemed to be the big problem. Ryle may- it's just possible that if you look in some of the remarks that Ryle did say something.

Sullivan: 21:55

He did. He called it the Schwinger mechanism.

Hoyle: 22:00

Yes, that's right. That's right. So you could say that he had the concept.

Sullivan: 22:04

Well, but he didn't follow up on it, though. He didn't put a student on it or something.

Hoyle: 22:08

That's right. I followed up on it. And I went to Caltech. I think it was at the end of the Michaelmas Term '53 in Cambridge. Because you have to remember we had very heavy teaching loads in those days. And I got away, and I got into the library at Robinson--

Sullivan: 22:35

At Caltech.

Hoyle: 22:36

--at Caltech.  Over Christmas, I got the theory. And that's why I talked about it in Washington. It was very hot in my mind at that time. I got it all then. And I was high on it. Especially as everybody was disagreeing with me, it never occurred to me that I wasn't the first. And of course, when Alfvén stood up and said, "But I did this with Herlofson," in his complaining voice, I was shocked. Because I rushed to the literature, and I found that he was right, that he'd done it. So I referenced him properly.

Sullivan: 23:12

When you were working on all these problems of the physics, were you concerned with all of the venues as it were of the radio, namely solar burst, radio sources, the galactic background?

Hoyle: 23:26

I'm concerned with the whole lot. That's right, yeah, yeah. So I was intrigued that it might do the whole lot. But there are obvious questions that you needed very high electron energies and so forth, but I felt very excited when I went to Washington for this. And as I said, I remember having a long talk with Charlie Townes about it. And he was intrigued, but he still preferred the plasma oscillator. I couldn't persuade Charlie that it was synchrotron radiation.

Sullivan: 23:55

And so by the time that your talk, you were quite convinced.

Hoyle: 23:58

I was convinced. But it's interesting that the whole astronomical community is just the herd instinct. The buzz word was plasma oscillation at that time.

Sullivan: 24:10

And would you agree that the thing that once again made the herd switch was largely the work that Oort did with Woltjer?

Hoyle: 24:22

No, it was Dombrowsky's discovery of the polarization of the Crab. And then he followed it up.

Sullivan: 24:28

Right. Once again, that didn't his impression [inaudible].

Hoyle: 24:31

It wasn't with Woltjer, no. Oort did it alone first. If you look, I think in the literature, it's a big paper by Oort, and then he put Woltjer on to it to follow it up.

Sullivan: 24:44

Right. And they were following up the Russian discovery. Once again, I don't think that Russian discovery made any impression in the West.

Hoyle: 24:48

No, but the Dutch verified. Of course, there's always been-- there's always been some doubt as to whether Dombrovsky really did it, but the Dutch verified it. And it was that-- and this happened very quickly. So it was a bad [crosstalk]--

Sullivan: 25:04

They came within a year.

Hoyle: 25:05

--we were on the verge of it. I felt I got it, and I had, but it was too late. And then the polarization came on and [inaudible].

Sullivan: 25:16

And then the problem became now, where do these high-energy electrons come from? Or let me ask another question before we get to that. Do you think that one inhibiting force might have been the fact that you had not actually detected electrons in the cosmic rays? Or was it really no problem? They were bound to be at least a few percent electrons, in the early ‘50s now.

Hoyle: 25:44

Well, I think the circumstance at that point undoubtedly weakened people's resolve to sort of investigate this. And I don't believe it was seen as-- I don't recall ever being criticized by people who said there couldn't be electrons, but had there been electrons, had it been known, then it would have driven people much more strongly.

Sullivan: 26:11

Because of course you had to assume some number for them and that certainly was a weakness.

Hoyle: 26:13

That's right.

Sullivan: 26:15

But now you had to go to the question of the source electrons and you had several papers where you talk about things like matter and antimatter.

Hoyle: 26:28

That's right.

Sullivan: 26:29

Papers with Geoff Burbidge on that. Another thing with--

Hoyle: 26:35

But didn't we decide finally it wouldn't work or something?

Sullivan: 26:37

To be frank, I haven't looked at that paper. I've just seen it in-.

Hoyle: 26:42

I seem to remember publishing an article [inaudible] in the Scientific American. And the conclusion was that it was going to be difficult to make it work.

Sullivan: 26:50

And then of course, like you said, you had the Cygnus double, which wasn't saying that radio radiation was nowhere near the optical emission. And so what were you making of it? I mean, you mentioned the name of Ambartsumian in a different context. Was that at all attractive in the late '50s? I know you went to that Solvey Conference in '58 where Ambartsumian was--

Hoyle: 27:16

It wasn't too bad, you see, because we'd had Fermi's theory of cosmic rays. And we also had the people who believed in collisions of galaxies. And so there were going to be a lot of-- I think one of the arguments I used, for instance, about the Cassiopeia source. I may have mentioned that in my note in Nature that the high velocity is there. So the possibility for working on Fermi mechanism on the electrons was there. So I don't think we were very worried about this. I mean, I'm pretty sure in that thing written in '54, I used the very high speeds of the Cassiopeia filaments in relation to Fermi's theory.

Sullivan: 28:05

Right. And that was often talked about as a common property of the identified sources.

Hoyle: 28:09

That they're always the--

Sullivan: 28:10

-sources, Cas and Perseus A and-

Hoyle: 28:16

So it all seemed to fit rather nicely to the idea of a pumping mechanism.

Sullivan: 28:23

You mentioned the colliding galaxies idea. That was another thing that was largely accepted. And the only thing that I can see why it should have gone on so long with really not that much evidence in its favor was the authority of Baade and Minkowski.

Hoyle: 28:36

I expect so. Yes.

Sullivan: 28:38

Would you agree with that?

Hoyle: 28:38

Yes, I would.

Sullivan: 28:39

And of course, Baade was very taken that they had worked on this theory of how you produce [unclear] zeros and then a year later, there it is on the plate.

Hoyle: 28:48

That's right, yes, yes. Baade was very excited. And of course, Baade was a very convincing champ. But Baade was the best convincing person I've ever come across because he didn't do it by authority. He did it by his ebullient personality, his friendly personality. And he was so bubbling in every direction that you felt impelled to believe him. There was no heavy Dutch father about Walter at all. It was all done in the most friendly--

Sullivan: 29:21

Was it maybe like Bart Bok personality?

Hoyle: 29:23

Yes, the same kind of personality, but backed up by an immense knowledge of observational astronomy. So he was full of arguments and so on.

Sullivan: 29:39

I mean, let me ask about Baade and Minkowski. It's amazing to me that these two men in the later stages of their career, age 50, 55 or so, embraced this radio astronomy and spent so much of their last parts of their career on this, what largely turned out to be fruitless. I mean, an awful lot of wasted time. Of course, some of it was very good. Do you have any insight into why they would have done that rather than sort of continue on with much more traditional astronomical studies?

Hoyle: 30:14

Yes. They were just before the big advance in photoelectric methods.

Sullivan: 30:24

That's right.

Hoyle: 30:25

And the thing which depressed Walter totally was the inability to calibrate accurately their photographic plates at low flux values. He said that the big problem, if only they could calibrate their plates, he would have a tremendous slew of discoveries, but he would not try to speculate. I told you before, it was from Walter I did get this feeling that the data had to be good. And he would never fudge his magnitude scale, as we used to call it. He was looking for, desperately looking for accurate calibration of his plates, accurate photoelectric calibration. And so he felt that he had all sorts of things there, but it was unsound. And so in that sort of position, he was waiting for the photoelectric parts. So anything he could do that was interesting in the meantime, he was going to do.

Sullivan: 31:28

So this qualitative science fit in very nicely. “Give me an accurate position and I can take some really good spectra and some really good” [crosstalk].

Hoyle: 31:36

That's right. It fitted what he--

Sullivan: 31:38

Yes.

Hoyle: 31:38

And he sort of felt that this was an interim period. He could see that the photoelectric methods were coming that would open out the field he really hoped to get into. And so it seemed all natural to him to go that way. I think that's--

Sullivan: 31:55

Interesting point of view. Because it seems to me that they were both conservative people, primarily.

Hoyle: 32:04

I mean, they were. They were.

Sullivan: 32:05

And yet they're embracing a very speculative field.

Hoyle: 32:07

But it was their very conservatism that they wouldn't shout aloud with inaccurately calibrated results that led them into it.

Sullivan: 32:14

Yeah, sort of ironically though, because the radio thing was not a conservative field at all.

Hoyle: 32:20

That's right. And of course, Walter hit the Cygnus A due to the fact that Graham Smith sent him the position.

Sullivan: 32:27

Yes, right.

Hoyle: 32:28

So that got him into it.

Sullivan: 32:30

But what about the fact that, of course, virtually none of the radio astronomers had any astronomy background at that time, but both of them had been trained as physicists also? Do you think there was any kinship there that they could-- many astronomers just wouldn't give the time of day to these people because they just weren't trained right. They didn't know what precession was and therefore they couldn't be producing anything worthwhile. Do you think there was anything there? Whereas they took them into the fraternity. I mean, this endless correspondence between Baade, Minkowski, and all of the major groups and they treated them as equals right from the start.

Hoyle: 33:12

That could be due to a difference of training. Walter started as a mathematician and I think Minkowski is a physicist. So they had come as it were. Astronomy wasn't their first discipline so that that could have been the reason.

Sullivan: 33:33

Yeah, I was just wondering. Well, let me just conclude with an overall kind of question. Looking at the era we've been talking about, the 20 years after World War II, what would you see as the way that radio astronomy influenced astronomy and astrophysics on two different fronts? The first in the way it was done, the style, as it were, and the second thing, the intellectual side, what we know about the universe. What are its real contributions?

Hoyle: 34:06

Well, I think it's very difficult at this distance removed to realize how shut in the astronomical world was, say, in 1945, when the Second World War ended. And that was particularly so in the UK. This was the, as it were, the first opening of horizons, which has continued, of course, with the other wave bands. They were running from the far infrared now to the X-ray region.

Sullivan: 34:47

Can you expand on what you mean by shut in? You simply mean confined to the visual, or do you mean confined mentally also?

Hoyle: 34:56

We were confined. What I mean is that we were shut in observationally and that led to a shutting in of the mind. Did you hear Don Osterbrock’s talk?

Sullivan: 35:12

Yes.

Hoyle: 35:13

But what was remarkable about that is that how much those early pioneers on the West Coast managed to do with what we could see nowadays as hopelessly, almost hopelessly crude instruments, because they had access to the world they were able to look. And that attitude that you have to look at the world was absent in the astronomy of 1945, particularly in the UK. It was absent also on the East Coast in the States. It was only on the West Coast.

Sullivan: 35:51

You mean sort of an exploratory view rather than setting up long projects on stellar statistics or on--

Hoyle: 35:58

Well, it's a question of which way around you write the logic. Eddington was a great believer that you really didn't need to observe the world because if your logic was good, you could deduce it. And Eddington was so good that he managed to do fine things with that attitude. But if the world is shut to you, that is the attitude you develop. In its most extreme form, it showed in the 15th and 16th century where they got into this tremendous religious syndrome when they couldn't get out of it because they had no input from the real world. I mean, Galileo, his crime to that society wasn't so much that he wanted the sun to be the center or the all bodies fall at equal speeds, it was the fact that he said, "No, your way of life is wrong. You've got to look at the world and allow the world to control you, not you controlling the world." That's the issue.

Hoyle: 36:56

And we were getting back into the sort of syndrome of trying to control the world. So in a sense, radio astronomy in Britain was an escape from that. And you could say the attitude of the older generation in resenting it was the same as the church resenting Galileo. It was a reflection of the same sort of syndromes on the two sides. And of course, the radio astronomers believed that they were-- they didn't realize that what they had was a gift of the world. They believed it was their own merit. And in that sense, to me, they were objectionable personalities, a lot of them.

Sullivan: 37:49

This is harking back to your previous comment about the universe is there.

Hoyle: 37:53

Yeah, that's right. It doesn't exist for us. I mean, we simply allow ourselves to be programmed by the universe. And in other words, they didn't have the necessary humility, so that might have added to it.

Sullivan: 38:04

You think that's true for them as a group? I mean, obviously, you feel that about Martin Ryle, and-

Hoyle: 38:09

Well, people like Bolton were okay. I mean, John--

Sullivan: 38:13

Were okay.

Hoyle: 38:14

But I think the whole group, to some extent, had its ego inflated by the circumstance.

Sullivan: 38:22

Well, so many fantastic discoveries following.

Hoyle: 38:27

I think you have to take a person like Jansky and say, "Well, he, as it were, deserved his success because he worked for it." But in another sense with the radio astronomers after the War, they didn't work. It wasn't their merit, as it were, that provided them with the techniques. It was the fact that we all worked during the War with these techniques. And it was those techniques that provided radio astronomy. And as it were, the people who came in on it were like those people who win the horse race in a certain sense.

Sullivan: 39:04

They had the tools, they had the--

Hoyle: 39:05

They had the tools, and the universe was there. And between these two, they couldn't fail. That's the situation. But I think it might have been Walter Baade who said to me, "Well, these people are--" I think it was Walter. He says, "I've seen it with the photoelectric people. They sort of feel that they are everything when the techniques first come in, but they eventually settle down and become a sort of part of astronomy generally." And he says, "You will see that that will happen to radio astronomy." And that's exactly what's happened. I mean, to be a radio astronomer today is to be quite ordinary. You have to be in X-ray astronomy or something like that to be the--

Sullivan: 39:49

Correct, gravitational.

Hoyle: 39:49

Yeah, [crosstalk].

Sullivan: 39:52

But then do you think that attitude in radio astronomy stayed on even beyond 1955, say?

Hoyle: 40:00

Oh, yes. Oh, yes. It stayed right on through the '60s. And in a sense, you can see in Bernard Lovell, he was-- in 1970, I was in a position where I could have handed Bernard a check for £4.5 million across the table to build a copy of the Bonn dish. But he wanted to build his own. And he wouldn't have cared if it was only one meter larger than the Bonn dish as long as it was the largest thing in the world. And actually, that project escalated. And I'm not sure just when the Research Council cut it off, but it was over 10 millions when they cut it off and said, "We're not going to do it." And he still feels he was badly done by. Well, I sort of feel that no man should feel that he's badly done by if a country is willing to spend 10 million quid on what he wants to do. So undoubtedly, due to the fact that they had the technique due to radar and that the universe was ripe, as it were, for revealing itself, but they took on the lottery sort of to themselves. And to some extent, that might have accounted for why the older generation reacted as they did.

Sullivan: 41:27

And so there were two aspects you're saying. There was the opening of the spectrum, obviously, but there was also the fact that their attitudes were different. And this led to conflicts with the older- Do you think there were any positive contributions of their attitudes to the--?

Hoyle: 41:47

Well, the positive contributions was to explore this business of being shut in. You see, they really ruled the roost in England because we have been shut in on the optical scars. But basically what they said was optical astronomy is unimportant. I've sat on committees where I've said it's not unimportant. It's a bigger subject than radio astronomy, except we can't do it. But now I've spoken against Lovell, but let me tell you the other side of the coin. Where a series of projects were there, there were projects for big telescopes and there was a project for the Anglo-Australian telescope. And Lovell stood back to allow that to go forward. So it's a very mixed bag. I mean Lovell had his great points as well as-- he was a great entrepreneur, you see. And so he had to go for what he wanted. But he should have gone for the Bonn dish. He should have gone for the copy. But he didn't like to feel that he was copying the Germans. And that was a mistake because that was a good telescope. But I suppose if he hadn't had this kind of character, he wouldn't have built the 250 foot.

Sullivan: 42:54

That's exactly right. Nor would Martin Ryle have developed aperture synthesis, etc., etc. If you hadn't had the--

Hoyle: 43:00

So you have to take it as it stands.

Sullivan: 43:03

Well, thank you very much.

Sullivan: 43:13

That's the end of the interview with Fred Hoyle on 22 May 1981 at a somewhat noisy outdoor cafe in Bologna on a nice sunny Sunday morning and a break day in the meeting for the Modern Cosmology in Retrospect. This is also the end of the side of the tape.