Pod Insights Short Wave This Radio Wave Mystery Changed Astronomy About this episode In 1967 Jocelyn Bell Burnell made a discovery that revolutionized the field of astronomy. She detected the radio signals emitted by certain dying stars called pulsars. This encore episode: Jocelyn's story. Host Regina G. Barber https://www.npr.org/people/1082526815/regina-g-barber talks to Jocelyn about her winding career, her discovery and how pulsars are pushing forward the field of astronomy today.
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Transcript Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.
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0:21 Regina Barber? Jocelyn Bell Brunel knows that in space, just as in life, nothing lasts forever.
0:27 Speaker 02 Bigger stars, at the end of their life, explode dramatically. They hugely brighten up, they kick out a whole lot of gas and stuff into space. And the core gets kicked against, gets compressed, gets shrunk right down.
0:43 Regina Barber? Massive stars more than 20 times bigger than our sun eventually collapse into black holes. Infinitely small points of immense mass that we can't directly see. Then, there are smaller stars, still bigger than our sun, that don't fully collapse into black holes.
1:01 Speaker 02 They're known as neutron stars because they're largely composed of one of the fundamental particles that we call neutrons.
1:10 Regina Barber? Those neutrons, they were created when the pressure from the explosion compressed the protons and electrons so tightly together, they combined.
1:18 Speaker 02 And so the core of the star becomes a ball that's about 10 miles across typically, and spinning very rapidly, a bit like the ice skater pulling her arms in, spins faster.
1:33 Regina Barber? A chunk of a neutron star the size of just a sugar cube would weigh a billion tons on Earth, or, no big deal, about the weight of a mountain. And because of that compression, these stars have much stronger magnetic fields.
1:46 Speaker 02 The strong magnetic fields keeps the charged particles constrained. And having lots of energetic charged particles confined to a small volume and whizzing around like fury. Will likely give you radio waves.
2:01 Regina Barber? Which is a good thing because
2:03 Speaker 02 Very, very few of them shine light. So we don't see them that way. We see them through the radio waves that they give out.
2:11 Regina Barber? These radio waves shoot out of the magnetic poles of some of these neutron stars as they spin. And on Earth, you'll only detect the radio waves if they happen to sweep across our planet, like the beam of a lighthouse.
2:23 Speaker 02 You only see them if they shine in your face or into your radio telescope.
2:28 Regina Barber? It looks like a pulse. That's why these particular stars are called pulsars.
2:34 Speaker 02 Pulsar is an abbreviation for pulsating radio star. I'm Jocelyn Bell Burnell. I discovered the first pulsar in 1967 and the second one and the third and fourth in 1968.
2:55 Regina Barber? Today on the show, Dr. Jocelyn Bell Burnell's story. How her astronomical discovery revolutionized an entire field of science. I'm Regina Barber and you're listening to Short Wave, the daily science podcast from NPR.
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4:31 Regina Barber? Jocelyn was just a teenager when astronomy took root.
4:34 Speaker 02 The real eureka moment for me was I was reading a book by Fred Hoyle, where he was talking about these big galaxies, you know, 100,000 million stars.
4:48 Speaker 02 And Fred Hoyle, in this book, was talking about how these galaxies rotate, spin about their center. And we're learning about this in school. And Fred's talking about these galaxies with stars rotating, and what keeps them going around in a circle and not flying off into space. I think, wow, I like this physics. I could be an astronomer and do this for a job.
5:13 Regina Barber? Life was just a blank page for her to fill in.
5:16 Speaker 02 And then somebody pointed out to me the obvious. Astronomers work at night. And as a teenager, in fact, even still now, I'm useless if I stay up all night. So I thought, oh, I can't be an astronomer. I can't work at night.
5:34 Regina Barber? That is, until she found a kind of astronomy she could do in the daytime: radio astronomy.
5:40 Speaker 02 Because the sun doesn't dominate the radio sky the way it dominates the light sky.
5:46 Regina Barber? So with a bachelor's degree in physics and a desire to be a daytime astronomer, Jocelyn starts graduate school at Cambridge, where she helps build the radio telescope that she used to detect the first pulsar. Although, at the time, that's not what she was looking for.
6:01 Speaker 02 I'm the person operating this radio telescope, looking for radio waves from stars and galaxies, particularly quasars, out there in space. I can't honestly remember what the definition was at the time I started, except that they were intriguing and mysterious.
6:21 Regina Barber? At the time, astronomers had only ever detected about 20 of these elusive quasars.
6:27 Speaker 02 And I got the number up from 20 to 200. We now know that they're galaxy mass things, but they have a huge black hole in their center, which really dominates their behavior in many, many ways. And we probably know of thousands by now.
6:43 Regina Barber? So Jocelyn searches for these quasars by detecting radio waves with this telescope. Basically, some of the light from distant stars reaches us as radio waves. And these antennae on the radio telescope focus those waves. The receiver detects those signals and turns them into data points on a page that look kind of like the marks on a polygraph.
7:01 Speaker 02 But in amongst all the data, there's a little signal that doesn't make sense. And the first couple of times I see it, I log it with a question mark and doesn't make sense. Pass on, there's real work to be done.
7:14 Regina Barber? And as one of the only women, she was very concerned about proving she was capable of that real work.
7:21 Speaker 02 I found Cambridge, when I was a grad student, really quite scary. Everybody there seemed terribly clever, terribly confident. And I was quite sure they'd made a mistake admitting me. So I'm working very, very hard and thoroughly to justify my place there.
7:39 Regina Barber? But as she's collecting data, Jocelyn saw that odd signal again. And she recognized it. So she goes back to her miles of paper data and finds another signal that doesn't make sense.
7:54 Regina Barber? And another.
7:55 Speaker 02 I've got five or six sightings of this thing, all from the same bit of sky. And that implies it's something astronomical.
8:06 Speaker 02 You're probably aware that the constellations you see in the night sky in summer are different from the constellations in winter. That's because the stars go round in 23 hours, 56 minutes, not 24 hours. Well, this funny squiggle, whatever it was, was keeping to the 23 hour, 56 minute pattern. So it was keeping its place amongst the constellations, whatever it was.
8:35 Regina Barber? But the pulses occupied only about a quarter of an inch on the paper. When she showed it to her thesis adviser, Antony Huish, he said she needed to enlarge it.
8:46 Speaker 02 And the way you get an enlargement is to run the paper faster underneath the pen, and it all gets spread out, an enlargement. So I had to go out to the observatory at the time this thing was due to be observed, switch over to high-speed chart recordings. And I did it for a month and nothing happened. My thesis adviser was livid, you know, it's been and gone and done it, and you've missed it.
9:11 Regina Barber? But she kept at it, and finally, she detected pulses again, this time in a string.
9:17 Speaker 02 One and a third seconds apart. And I went to the trouble of actually telephoning him to tell him the news, and he was rather disbelieving. But he came out the next day, stood as I wired up for this special observation check that I was doing everything properly. And bless it, it performed again, and he saw it with his own eyes. And we could see immediately it's pulsing at the same rate as yesterday. For something to keep pulsing steadily, it has to be big. But it also had quite sharp pulses, which meant it was small. So that was our conundrum, along with what the heck could it be and why is it going
10:02 Speaker 02 at this very fast rate of one and a third seconds?
10:05 Regina Barber? Antony Huish presented the data to an audience of scientists. The data lit up the scientific community and other researchers switched gears, looking for more evidence of these pulsating radio waves. Soon, scientists concluded that the radio waves the telescope was picking up were from a neutron star's poles. And so when spinning, they might sweep the radio waves across Earth. The discovery of pulsars amounted to a 1974 Nobel Prize in Physics for Antony Huish, which he split with astronomer Martin Ryle, who hugely advanced the sensitivity of telescopes.
10:43 Regina Barber? After Jocelyn made her landmark discovery, she married Martin Burnell, and her career took a turn.
10:49 Speaker 02 At that time, there wasn't any way of keeping my maiden name, so I lost that as well and kind of lost my scientific reputation. And I married a person who had to move every five or 10 years because of their job. And so my "career," note the inverted commas, has been really, really peculiar.
11:14 Regina Barber? Peculiar because with each move, she looked for a new astronomy job.
11:18 Speaker 02 I was begging for a job at the nearest astronomy place to where my husband was about to go and work. And quite often got the kind of jobs you get when you go begging.
11:29 Regina Barber? And so the work wasn't always in radio astronomy, the field where she made her name unmarried.
11:35 Speaker 02 But it's actually worked out quite well. My curriculum vitae doesn't look too wonderful, but I have had huge fun working in many, many branches of astronomy, often landing in a new branch of astronomy just as it was about to boom. And I'm known for my work in several wavelengths. So, okay, I can live with that.
11:59 Regina Barber? Today, pulsars allow astronomers to measure cosmic distances, look for gravitational waves, and search for planets beyond our solar system.
12:08 Speaker 02 The legacy. It's been a huge help to me through a rather difficult career that I've had the discovery of pulsars under my belt. Our understanding of the universe keeps evolving. Clearly, pulsars are one key component of that. There's a lot more work to do on pulsars, and I think there's plenty more unexpected things to trip over if you keep your eyes open.
12:44 Regina Barber? Thanks, as always, to you listeners for tuning in. And we asked you for some of your favorite space facts.
12:51 Speaker 04 This is Lisa Latu in Kyle, Texas. My favorite space fact is that it takes about three days to get from the Earth to the moon in a human spacecraft. I use that to help me imagine how much further away it is to other destinations.
13:08 Speaker 05 Hi, this is Rotem from Pittsburgh, Pennsylvania. My favorite space fact is that Venus orbits around the Sun faster than it rotates around its own axis. So a Venusian day is longer than a Venusian year. That's the kind of three-day weekend I can totally get behind.
13:25 Regina Barber? This episode was produced by Burley McCoy, edited by Rebecca Ramirez, and fact-checked by Rachel Carlson. The audio engineer was Natasha Branch. Gisele Grayson is our senior supervising editor. I'm Regina Barber. Join us again tomorrow for more Short Wave from NPR.
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