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Q&A: Pulsar pioneer Jocelyn Bell Burnell

30 January 2019

Years after being overlooked for the most coveted prize in physics, she was recently awarded the one with the biggest purse—and she donated it to help underrepresented graduate students.

As a graduate student in the 1960s, using the radio telescope she helped build, calibrate, and debug, Jocelyn Bell Burnell spotted the signal and performed the data analysis that led to the discovery of radio pulsars. In 1974 Antony Hewish, who had been her thesis adviser at Cambridge University, received the Nobel Prize in Physics for his role in the discovery. Her exclusion from that prize is widely seen as one of the biggest Nobel snubs; some of her contemporaries called it the No-Bell prize. She, however, says she doesn’t hold a grudge against the Nobel committee. Last year, a half century after her first publication on pulsars, she was honored with the Special Breakthrough Prize in Fundamental Physics. She is donating the $3 million that came with it.

Jocelyn Bell Burnell
Credit: Royal Observatory, Edinburgh

Over the course of her career, Bell Burnell worked at several universities, was a project manager for the James Clerk Maxwell Telescope on Mauna Kea, and served as president of the Royal Astronomical Society and then the Institute of Physics. She is now a visiting professor at Oxford University.

PT: How did you get into science?

BELL BURNELL: I nearly didn’t get to do science. At my school in Northern Ireland, girls were expected to do needlework and cookery. My parents had promised me I’d get to do science, so I was a bit miffed when the girls were shunted over to the domestic science room. This was at about age 12.

I tried protesting, but the teacher wasn’t hearing me. So I told my parents that evening. They were furious and phoned the head teacher, as apparently did the parents of two other girls. The next time the science class met, there were three girls and all the boys.

PT: What attracted you to astronomy?

BELL BURNELL: I was clearly good at physics, pretty good at chemistry, and not interested in biology—which may say something about the teachers and what they were teaching us. So it was ultimately a question of “What kind of physicist am I going to be? What am I going to specialize in?” I read some astronomy books from the public library and decided I would be an astronomer. This was at about age 15.

PT: How did you end up in radio astronomy?

BELL BURNELL: I decided on radio astronomy before I left secondary school. I realized that if I did optical astronomy, it would involve staying up at night. I already knew that if I didn’t get my night’s sleep, I physically couldn’t function. But I realized there were more modern kinds of astronomy, like x-ray and radio, that were 24-hour-a-day jobs, so you could keep more normal hours. I chose radio because I knew more about it. It was still very pioneering.

PT: But you got your undergraduate degree in physics, correct?

BELL BURNELL: Yes, I stuck with physics because I already knew enough astrophysics to realize that the courses at university in Glasgow were old-fashioned. They did a lot of spherical trigonometry. Then I applied to do a PhD in radio astronomy. I went to Cambridge, rather to my surprise.

PT: Why was it a surprise? And how was it?

BELL BURNELL: They have very high standards, and I didn’t think I’d get in. But I did. It was quite daunting to begin with, because everyone seemed terribly clever. Cambridge seemed very suave and confident, and I really thought they’d made a mistake admitting me. With hindsight, I can see I was suffering from impostor syndrome.

PT: How did you adjust?

BELL BURNELL: I was sure they’d throw me out at some stage. And I made a conscious decision to work my hardest so that when they threw me out, I would know I had done my best. I wouldn’t have a guilty conscience.

PT: What was the topic of your PhD studies?

BELL BURNELL: It was a radio astronomy project to find quasars, which were the hot, sexy thing at that point in time. I worked with Tony Hewish, who had just received a grant to build a new radio telescope.

PT: So how did you find pulsars?

BELL BURNELL: I spent the first two years helping to build the radio telescope. I was the first person to use that telescope. I was very thorough to make sure I understood how the telescope behaved, what were bugs, what was real, that kind of thing. I found a lot of quasars—I got the total number discovered up from about 20 to about 200.

And then there was this one signal that I reckoned occupied about 5 millimeters in 500 meters of chart paper. I couldn’t make sense of this little signal. It didn’t look like a quasar, it didn’t look like manmade interference, and I didn’t think it was some bug with the telescope. It was present only intermittently.

Bell Burnell as a graduate student
Jocelyn Bell Burnell at the Interplanetary Scintillation Array, the radio telescope she helped build, in 1968. Photo courtesy of Bell Burnell

Once I realized that the signal always came from the same part of the sky, I showed it to my supervisor. He rightly observed that if it occupies only 5 millimeters, it’s a bit hard to see what’s going on. We needed to see some kind of enlargement, which involved me going out to the observatory each day just before the telescope would observe that bit of sky. I would switch to a higher-speed recorder and then revert back to normal speed when that bit of sky had gone past.

Finally, after a month, I got it. It turned out to be this string of pulses, 1⅓ seconds apart, which is not what you would expect—such a thing had never been seen before in radio astronomy. Tony said, “That settles it, it’s manmade,” meaning it was radio interference generated by human beings. But I didn’t believe that, because it was keeping its place amongst the stars, and it had been doing that for three or four months by that stage.

Tony came out to the observatory the next day and stood looking over my shoulder, and fortunately the thing reappeared, and he saw the pulses for himself. At first we couldn’t make sense of the observations. Short, steep pulses imply a small object, but it was keeping the same period, so it wasn’t getting tired, which implies it’s got big energy reserves, which implies it’s big. It’s hard to reconcile those two things. It turns out it has to be small in radius but large in mass. It took us a while to make that leap because nothing so extreme had been seen before.

PT: Did you realize you were making an exciting discovery?

BELL BURNELL: Increasingly, yes. But to begin with you are cautious, because there are so many things it could be that are extremely mundane. We worried about all kinds of things.

We continued to worry that it was an artifact of the new telescope. Tony wondered if I’d wired the telescope up wrong. We got a colleague to look for the signal with another telescope. And this other telescope did see it, so there was no fault with our telescope in that sense. But could it be interference of some sort?

Then I found a second signal in a different part of the sky with a slightly different pulse period. And about three weeks later I found another two. So it began to look like something genuinely astronomical. A colleague managed to estimate the distance to the first one. He put it at about 200 light-years away, which puts it beyond the solar system but well within our galaxy. We wrote it up and published it. That was in 1968.

PT: What was the response of the astronomy community to that paper?

BELL BURNELL: There was huge excitement. There was enormous press interest. Tony and I did a lot of interviews.

It was very revealing the way the pair of us were treated by the press. They’d ask Tony about the astrophysical significance of the discovery. And they’d turn to me for what they called human interest. They’d ask for my bust, waist, and hip measurements. How tall was I? What color was my hair? How many boyfriends did I have? The photographers were asking me to undo more of my blouse buttons.

PT: How did you react?

BELL BURNELL: It was very, very uncomfortable. I would have loved to be rude to them. But I was still a graduate student. I hadn’t even started to write my thesis. I needed references from people in my department. I felt I couldn’t rock the boat. But it was horrible.

PT: Did Hewish step in for you at all?

BELL BURNELL: No.

PT: Did you write your thesis on the pulsars?

BELL BURNELL: I would have liked to focus on the pulsars. But Tony said it was too late to change the title of my thesis, so the thesis had to be on the quasars as originally planned. I think now, knowing what I know about university systems, that he was wrong. But I put the pulsars in as an appendix.

PT: Where were you and what did you think when the Nobel was announced in 1974?

BELL BURNELL: By then I was working in x-ray astronomy and having a grand time. I was delighted when I heard the news. I knew it created a very important precedent. There is no Nobel in astronomy, and until then, no astronomer had received a Nobel Prize. I was proud that it was my stars that had convinced the committee that there is good physics in astrophysics. I wasn’t too bothered not to get it. The Nobel committee didn’t normally recognize students. It didn’t even know how many students there were, what gender they were, what their names were. Students were in the noise.

PT: Why did you switch from radio to x-ray astronomy?

BELL BURNELL: Well, I got engaged to be married between discovering pulsars two and three. At that time in Britain, it was considered shameful if a married woman had to work—it meant the man couldn’t earn enough to keep them both. And on the radio you could hear people telling you that it was proven that if a mother worked, the children would be delinquent. There weren’t any nurseries or childcare facilities. So when we had a child, which had happened by the time of the Nobel Prize, I was finding it very hard to keep working.

I worked in whatever job I could get near where my husband was working. I’ve done a huge variety of jobs—not just the regular academic researcher kinds of jobs.

PT: Did you stay in science?

BELL BURNELL: There was always science content, but sometimes I was in management roles. Working in x-ray astronomy was one of the most exciting bits, from 1974 to 1982. On behalf of the Mullard Space Science Laboratory at University College London, I was in charge of a satellite that turned out to be hugely successful. We were working with the x-ray spectrometer on the Ariel 5 satellite. The data came in to me, and I passed them out to the various members and students. It was a very exciting and dynamic time. We found transient sources. We found a number of pulsing sources. We found iron emission from clusters of galaxies.

PT: Why didn’t you remain in a field you found so rewarding?

BELL BURNELL: Because husband moved again. So the pattern was, I went from radio astronomy as a graduate student to gamma-ray astronomy. Then husband moved, and I went to x-ray astronomy. Husband moved, and I went to infrared and millimeter. I’ve covered most of the spectrum.

After the marriage broke up, I was free to go after jobs because of what they were, not where they were. In 1991 I became chair of the physics department in the Open University near London. It teaches adult students who are working at home, so most of the teaching is done by correspondence. You have to have very high-quality material with lots of things for the students to do so they don’t doze off, because they are probably studying in the evening after work. I also tutored, and it was great fun, because the students were really keen to learn.

After that I went to the University of Bath to be dean of the science faculty. That was my final job before retirement about 12 years ago.

PT: Last year you were recognized with the Special Breakthrough Prize—the same year that a woman won the Nobel Prize for the first time in 55 years. Was that a surprise?

BELL BURNELL: Absolutely, yes. I hadn’t really registered that this Breakthrough Prize existed. The first I heard of it was when I got a telephone call from Ed Witten, the chair of the selection committee.

PT: What are you doing with the $3 million in prize money?

BELL BURNELL: The UK’s Institute of Physics is using it in a scheme to fund graduate students who are underrepresented in physics—women, people of color, refugees, and people from underrepresented socioeconomic groups. The idea is to improve diversity in physics departments in the UK and Ireland.

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