Antony Hewish interviewed by Alan Macfarlane 26th March 2008

0:09:07 Born in Fowey, Cornwall, in 1924 where my father was a banker; left within a year of my birth for Newquay where I was brought up; before the war it was a nice, unspoilt, holiday town; I went away to school in Taunton but came back for holidays where I spent time crabbing and enjoying the sea; I was interested in physical things and with tolerant parents we were able to do minor experiments at home; we used to pull the mains leads out of the wall and get connected up; I am the youngest of three brothers, and the middle brother, John, was rather technically minded and interested in building model aircraft and things of that sort; jointly we did all sorts of crazy things like making explosives and I particularly tried electrolysis using the mains, which didn't help because it would plunge the bank, which we lived above, into darkness; mucking about in a scientific way was where I got my interest; the sea was in the background for swimming and fishing; father was not an intellectual; his parents were drapers in Barnstable, Devon; he was not technically minded and never knew how things worked; we were just born with this natural curiosity; I was always wanting to know how things worked and would take them to pieces; in those days you could buy everything you needed for experiments such as the ingredients for gunpowder; mother was a farmer's daughter from Cornwall; she did not much like the sea but did like the countryside; she was not academic in any way though one of her sister's was

6:10:04 First went to school in Newquay but then went to King's College, Taunton, a smallish public school when I was about twelve; I went into the preparatory school first then the main school, in all there about seven years; my physics master, Padfield, was a Caius man which is why I went there when I came up to Cambridge; he was not a great physicist and was probably better at hockey than physics; I can't say that I got great inspiration from my schoolmasters; I think my interest was self-generated; schools were much more tolerant then and you could just wander into the chemistry lab. and play around with things; could make nitrogen triiodide which almost ignites by looking at it; my brother John was at the school; older brother, Paul, was six years older and he went into banking; moderately enjoyed school but I was not really athletic or sporty; had to play rugger most afternoons which I tolerated; the pinnacle of my school career was getting house colours for cricket; my interest in music came later in life, with my marriage; did not sing at school as had chapel twice a day and that was enough for me; did play in the bugle band for the O.T.C. as it saved you from too much square-bashing; my wife plays the piano and encouraged me to go to concerts; I simply love chamber music and opera now

11:50:08 I am rather down to earth; I had not great aspirations to solve the riddle of the universe just that when I came back after the war I had some electronic technology that I understood and discovered it was going on in Cambridge and began research there because it was the obvious option for me; had not planned to be an academic and no one predicted that I would get a first in my Part II; there was a desperate shortage of trained scientists during the war that you could get to Cambridge very easily and they would fund you; I came up to the University in 1942 as a radio bursar as they wanted scientists in radio and radar; it was a two year accelerated course for Part II of the Natural Sciences tripos; because of my background in rowing at Newquay I spent too much of my time on the river in my first year and didn't do very well; told I should go and do something useful for the war effort and directed to the Royal Aircraft Establishment, Farnborough, after just one year; spent three years there until just after the war ended, for which I was immensely grateful as I began to understand what physics and some aspects of maths were really about in a way that I hadn't realized when I was an undergraduate; I recommend that people go to university rather late in life; at eighteen I wasn't very well versed in how the world works; boarding schools kept you enclosed and we weren't even allowed to go into Taunton

15:12:14 At Farnborough initially worked on radio communications but I hadn't been there more than a few months before I was directed to T.R.E. (Telecommunications Research Establishment) which was the home of the boffins where radar was essentially invented during the war; all airborne radar applications were going on there and I had the job of training the aircrews on how to use it; my job was called P.D.S. (Post Design Services); having worked on the development of a particular gadget and seen it through the production stage then you went out to the squadron where it was being fitted; in my case this was Bomber Command and I was involved with a device for jamming German airborne radar; what the devise did was to radiate noise at high power from the tail end of a B17, the American Flying Fortress, and these aircraft flew in the bombers' stream with the idea of blanketing the German interception radar on their night fighters; don't know how effective it was but my job was to teach the ground crews how to service it; it was not a design job from my point of view though I had to know exactly how it worked; that is where I first met Martin Ryle as he was head of that radar counter-measures group; he was two or three years older than me, an Oxford man; he was in charge of developing the gear at T.R.E. (Telecommunications Research Establishment), Malvern, so I got to know him pretty well; I had no idea that he had returned to Cambridge when I was looking around to see what research I could be involved with; discovered he was here and it was the obvious thing to do; you could not be in his company for long before realizing how immensely bright he was; he always thought of solutions before you did; he was a reserved sort of man with a short temper, but also immensely kind; I found him a wonderful person to work with

18:35:05 After the war came back to finish my degree; it was a wonderful time to be in Cambridge because all the ex-service people were coming back so you were in the company of people you had been with; the post-war years were legendary, if you talk to tutors who are still alive now, they wanted to learn, they worked hard, they didn't play around; I didn't naturally find physics easy, mathematics just doesn't flow into my head and I have to work rather hard; after the war I realized what the mathematics was doing because this had been used in my wartime experience; I spent no time on the river, worked hard, and ultimately got a first; that again was partly due to my wartime contacts as the man who was running radio physics at the Cavendish Lab., Jack Ratcliffe, who had been a research student with Edward Appleton who had discovered the ionosphere; Ryle had gone to work with Ratcliffe after the war; Ratcliffe had been a very influential teacher and his courses on electro-magnetism were legendary and when I found I could do research in Ratcliffe's group this was an obvious thing for me to do; I had not planned to be an academic and had got jobs lined up but when I discovered there were interesting things to do for which I was fairly well equipped, and I had met my girlfriend in Cambridge who was teaching here, so I decided to stay on; Ratcliffe had been head of the Post Design Services Group at T.R.E., Malvern, and I had interacted with him during the war; he was a big influence on me

22:48:22 Of colleagues, Graham Smith was at T.R.E. and was a year ahead of me; he came back to Cambridge to do research as he had done a rapid two year course so he was fully qualified; he was working with Martin Ryle; Ryle began research in 1946, I began in 1948, and Smith had joined in 1947; it was picking up wartime connections as it was in a sense a continuation of our wartime work together; no one knew that it was going to open a new universe to us, we were just playing around with the technology we understood and investigating these strange radio waves from the sun initially, because radiation from the sun was a wartime discovery; that was how radio astronomy began in this country; discovery made by a man called James Hey who was with Operational Research with anti-aircraft and on one day the anti-aircraft radars were swamped; this was in February 1942 just after the pocket battleships had made their dash through the channel; it was thought initially to be some sort of German secret weapon but he realized that it was coming from the sun when he found that all radars were picking up radiation from a certain direction; he phoned the Royal Greenwich Observatory to ask if there was anything funny happening with the sun at that moment and found that there was a sunspot right in the middle of the disc; that was a secret wartime discovery but Ryle thought this would be a good thing to research when he got back to Cambridge; of course radiation was coming from other directions too; I got in at the beginning of the investigation so was extremely lucky

25:46:00 I was not studying astronomy for its own sake; what I had discovered in about the first year of my research from these few, what we now know, radio galaxies (we called them radio stars in those days), that the radiation fluctuated in time; it wasn't clear whether this was an intrinsic variation of the sources themselves or whether it was a propagation effect, whether the radiation was being affected on its traverse through the upper layers of the ionosphere here; Graham Smith had already made measurements which suggested that it was an ionospheric effect and I took that up and confirmed that in fact the fluctuations were caused by mainly nocturnal disturbances in the ionosphere; it was my initial research that led to the discovery that this only happened at night, and that this was a good way of using extra-terrestrial radiation to probe the atmosphere at heights which were then unreachable by any other method; because the astronomical side hadn't really developed I got diverted into using extra-terrestrial radiation in studying the upper atmosphere; Jack Ratcliffe, who was an atmospheric scientist essentially, was keen that I did this and he gave me great support; in my thinking about this I developed a theory which pleased him a great deal and I latched onto this as my own particular research area; it is nice when you are a graduate student to have something you can call your own; Martin Ryle was so bright that he had thought of all the clever things to do, but here was something I could develop on my own, and that was what my thesis was all about; in investigating the fluctuations I was the first to measure wind speeds in the upper ionosphere; this was research I could manage on my own with not a great deal of technical requirement; the radio telescope technology was quite elementary but it was all new and you couldn't help but make new discoveries and publish papers, which is just what you need as a starting graduate student; this was before the array telescopes in Cambridge and were using army surplus equipment set up on the rugby ground behind the University Library (still called the old rifle range) which was where Martin Ryle began; I built my own primitive radio telescopes to do my own particular jobs but they were only little bits of wires strung between poles, the sort of thing you could build in a week or two; this was the sort of thing I had been doing as a child which was the joy of it in those days; you could make very nice discoveries with very simple, basic, apparatus; this was research for which we didn't have to fight for funding as we had enough in the Cavendish to support the sort of work I was doing

31:58:09 From the beginning was aware of the EDSAC computer because Martin Ryle was famous for his invention of aperture synthesis using simple radio telescopes in different positions and adding up the data; essentially you are Fourier analysing the sky and you need a computer to analyse the data; in the very early 1950's Ryle was experimenting on using EDSAC in its earliest form to analyse the data from the simple interferometers he was then using to make simple maps of the sky; it didn't help me to start with but later on I got very involved with it because someone had to do the early programming, and that fell to me; I didn't use computers in my own work and we were recording with pens on paper; the digital world just hadn't begun; didn't know of Alan Turing or Bletchley Park until much later

34:02:03 After my Ph.D., where I had originally worked on the ionosphere we then discovered that radiation passing through the sun's atmosphere was similarly affected; having had the background of working on ionospheric disturbances I then began to study disturbances in the solar atmosphere and my work naturally extended out towards the sun; it developed into studying what we now call the solar wind, the outward expansion of the sun's atmosphere which blasts out into interplanetary space at speeds of 3-400km per second; the solar wind became known as space research began and before that era I was studying the solar atmosphere as it left the sun; the sun's atmosphere can't be seen optically with instruments except at total eclipse; to have a means of detecting anything to do with the solar atmosphere at other times was useful; I tracked the solar atmosphere and studied irregularities in it almost to halfway between the sun and the earth; that kept me busy for my own personal research and resulted in several publications; at the same time I was helping Martin Ryle in the design of his really big radio telescopes which made the first ground-breaking sky surveys in this country; it was Ryle's idea to spread the array far apart and went hand in hand with the development of computers; when you are analysing the data from these multiple interferometers - you can synthesise a radio telescope that you couldn't possibly build; Bernard Lovell was designing a 250 ft dish at Jodrell Bank, but Martin Ryle was a little bit scornful about that as not having the power that we needed; what you wanted was a telescope a mile across; the way he did this was to make smaller dishes which are easy to build and not too expensive and pick up the data sequentially when these are in different positions; then you can synthesise all that in a computer to reproduce exactly what a mile wide bowl would actually do; Ryle's telescopes elaborated as computers elaborated; eventually the telescopes were on a railway track; Mullard kindly provided the money to move our work from the old rifle range to the new site at Lord's Bridge; they gave us £100,000 to set up the Mullard Observatory, establishing the site and the buildings; most of the money for the instrumentation came from the Department of Scientific and Industrial Research

39:49:03 Scintillation is a grand title for twinkling, all stars twinkle; what happens is that the upper atmosphere, even on the clearest night, has air in it of varying wind speeds and density and there are clouds of different density up there; the radiation coming through is bent in different directions; looking through the earth's atmosphere is like looking through a crinkly bathroom window; what you pick up is not a pure undisturbed wave front; it is the same in radio astronomy except the physics is somewhat different; scintillation is the name given to these fluctuations

41:23:07 At this time we were in the old Cavendish Laboratory at the top of the colloid science building; I was there from 1948 until 1972 when we moved to our new site; when we had discovered the sun's atmosphere, I did  a calculation in 1952 which seemed to me to rule out the possibility that you would ever see scintillation caused by the solar wind; in those days when we had a handful of extraterrestrial radio sources, the mixture of supernovae and radio galaxies, they all had a rather large angular size of several arc minutes, about the size of a moon crater; I had calculated that you would never see twinkling through the solar atmosphere because the sources were much too large; stars twinkle but planets don't; the moon doesn't twinkle as it has a much too large angular size; when I looked at the calculations of what the solar wind was doing I realized that you would never see scintillation because the sources were much too large so I never bothered to look for it, which was a great mistake; we discovered quite by chance in 1964 that in fact some radio galaxies did twinkle; it was a mystery as to why they should but a graduate student noted that they twinkled when they were not too far away from the sun but never when seen at a large angular distance from it; we used to have Saturday morning discussion groups and Martin Ryle and I were talking about this; he asked whether it could be scintillation and I said it could be if they were of a very small angular size; it turned out that the ones that twinkled best were the ones that by then Jodrell Bank had discovered were in fact rather small; decided to do an experiment which I did with a colleague at Lord's Bridge and we discovered that a lot of the galaxies twinkled; this opened up the whole field of interplanetary scintillation; certain radio galaxies, which we now call quasars, twinkled through the solar wind; my work on the ionosphere and solar atmosphere suddenly extended; I realized that I could use this twinkling of certain radio galaxies to measure the speed of the solar wind which was enormously interesting as it had just been measured by the first Russian space craft; I decided to measure the solar wind on the ground and that is when my research took off; I set up a grid of radio telescopes across England and successfully measured the solar wind from the ground; this scintillation pattern of radio intensity sweeps over the ground and was crossing England at 3-400km per second but I could just measure the delays as it crossed my radio telescopes; I rapidly got graduate students to help and we measured the solar wind on the ground in competition with the early spacecraft; I was doing it for a few hundred pounds whereas it was more like £20,000,000 from space; we could do better than spacecraft in that we could measure the solar wind coming from the polar regions of the sun which spacecraft didn't manage until the 1990's; we found the solar wind was coming off the poles faster than it was blowing off the equator; this research led on in a natural way to the pulsars

49:16:21 I developed the interplanetary scintillation technology and used that as a tool to measure angular sizes of radio galaxies; a scintillation varies strongly as you look at a particular source, whether it is close to the sun or far from it; there is much more scintillation when it is nearer the sun; if you apply diffraction theory to that you can see that this is a method for actually measuring angular sizes using an angular resolving power which is much higher than you can get with any sensible radio telescope; the wave lengths I was observing the scintillation on I could get an angular resolving power which would otherwise require a radio telescope bigger than the diameter of the earth; we were then beginning to understand more about quasars; in Martin Ryle's surveys of the sky about a thousand or so radio galaxies were then known but it was not known what the radio galaxies were; one or two quasars had been discovered which had the property that they have a very bright nucleus and send jets in different directions; they have components which are a tiny angular size and it is those components which twinkle; I thought we should carry out a sky survey to see which of the thousand radio galaxies are the most interesting ones astrophysically, which are the quasars; I could do that seeing which ones scintillated most strongly and I could actually measure angular sizes; I developed the technology and set up a survey but it required a very unusual instrument; it had to be sensitive to see enough radio galaxies, working on a longish wave length which is where the twinkling shows up best, and it wasn't like any existing radio telescope; I had to build my own telescope which consisted of 2000 dipoles spread out over a four acre field; it observed the radio sources as they crossed the meridian and according how much or little they scintillated I could measure the angular sizes and sort our which ones were quasars; my survey was operating by 1967 and it was during that the pulsars turned up; this was a telescope we could build with our own effort and not too expensively; on present day funding it would cost about £1,000,000 and in those days it cost about £20,000; I persuaded a committee that this was worthwhile and got funding; I was planning the telescope in 1965 and it was in operation two years later; with that instrument it was impossible to avoid pulsars as their fluctuations are in the same time scales as the scintillations I was looking at

54:29:14 Messages came along coaxial cables and went on to pen recorders for reasons of economy and speed; digital recording of the quantity of data that I was handling then wasn't a very practical solution; we originally had three then four paper charts and it was my industrious student, Joscelyn Bell, who had the task of analysing all these; she was the first to see something strange going on; initially she pointed out a record which was showing too much scintillation in the middle of the night when you are not looking through a dense part of the solar wind; normally our radio galaxies only scintillated about a 10% level and what she noticed was that there was a rather faint source scintillating at 100% level in the ante solar direction; we didn't know what it was or even if it were a genuine signal; after it had reappeared we surveyed the whole sky roughly once a week and it had appeared two or three times; neither of us fully believed that it was a genuine source; decided to have a closer look; it could be something like the initial radiation from the sun which was discovered by Hey; perhaps there were stars in our own galaxy which are a bit like the sun but a bit further off which radiated intense noise when there were sunspots on them, but I realized that the radiation we would get from such a source wouldn't look like the normal interplanetary scintillation; decided to run a fast record and take a close look at the scintillations and their time structure; it took two or three months to get some good recordings but when we looked at the fluctuations more closely it was clear that they were pulsing; it was a shattering blow really; discovered pretty soon that it had to be beyond the nearby stars but was way out in our own galaxy as a stellar source; all kinds of thoughts went through our minds; it was such an artificial signal that I had to seriously consider that the signal was being sent to us; we could measure the size of the object launching the signal which couldn't have been larger than a planet; we had the problem of regular flashing signals from an object of planetary size or less without knowing what it could be; we were very careful to keep quiet as we had already had our fingers burnt; in 1957 we were the first group of radio astronomers to locate the Russian sputnik; everybody knew it was up there as you could hear it bleeping but nobody quite knew where it was; we set up a simple interferometer at the old rifle range and got the rough orbit; the press descended in hoards and filled the lab. asking stupid questions and normal work was quite impossible; they couldn't detect it at Jodrell Bank as they didn't know where it was until we sent its position to them and then they picked it up immediately; now we had a real mystery and the moment anything leaked out that we were picking up something strange, possibly intelligence, what would have happened?