This Radio Wave Mystery Changed Astronomy

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. Have cosmic queries and unearthly musings? Contact us at [email protected] mailto:[email protected]. We might open an intergalactic case file and reveal our findings in a future episode. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave http://plus.npr.org/shortwave. See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  This message comes from Avalara Aviator. Aviator is the agent hub for tax and compliance. Purpose-built AI agents work around the clock and across business systems to help execute the work. Visit avalara.com/aviator.

• 0:15Speaker 00

  You're listening to Short Wave from NPR.

• 0:21Regina Barber?

  Jocelyn Bell Brunel knows that in space, just as in life, nothing lasts forever.

• 0:27Speaker 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.

• 0:43Regina 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.

• 1:01Speaker 02

  They're known as neutron stars because they're largely composed of one of the fundamental particles that we call neutrons.

• 1:10Regina Barber?

  Those neutrons, they were created when the pressure from the explosion compressed the protons and electrons so tightly together, they combined.

• 1:18Speaker 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.

• 1:33Regina 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.

• 1:46Speaker 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.

• 2:01Regina Barber?

  Which is a good thing because

• 2:03Speaker 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.

• 2:11Regina 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.

• 2:23Speaker 02

  You only see them if they shine in your face or into your radio telescope.

• 2:28Regina Barber?

  It looks like a pulse. That's why these particular stars are called pulsars.

• 2:34Speaker 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.

• 2:55Regina 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.

• 3:09Speaker 03

  Stay tuned for the following announcements and messages from our sponsors.

• 3:14Speaker 00

  This message comes from ProLon. Want to look and feel your best this fall? ProLon's five-day fasting-mimicking diet is a clinically-developed nutrition program with the goal of promoting fat loss while protecting lean body mass. Developed at USC's Longevity Institute, it aims to assist the body in entering a fasting-like state that helps reset metabolism, target visceral fat, and support healthy metabolic markers. Get 15% off plus a bonus gift when you subscribe at prolonlife.com/NPR. This message comes from Avalara Aviator. Aviator is the agent hub for tax and compliance. If you've listened to enough podcasts, you know a confident answer isn't necessarily a correct one. Sources matter. The same goes for AI, tax, and compliance.

• 3:59Speaker 00

  Aviator is grounded in 20-plus years of Avalara tax intelligence and delivers source-backed audit-defensible outcomes with human oversight built in. Because the AI said so, won't pass an audit. Visit avalara.com/aviator.

• 4:14Speaker 00

  This message comes from Schwab. At Schwab, you can get everything from self-directed investing to full-service wealth management, all in one place. No matter your investing goal, life stage, amount to invest, or know-how, you can invest your way with Schwab.

• 4:31Regina Barber?

  Jocelyn was just a teenager when astronomy took root.

• 4:34Speaker 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.

• 4:48Speaker 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.

• 5:13Regina Barber?

  Life was just a blank page for her to fill in.

• 5:16Speaker 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.

• 5:34Regina Barber?

  That is, until she found a kind of astronomy she could do in the daytime: radio astronomy.

• 5:40Speaker 02

  Because the sun doesn't dominate the radio sky the way it dominates the light sky.

• 5:46Regina 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.

• 6:01Speaker 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.

• 6:21Regina Barber?

  At the time, astronomers had only ever detected about 20 of these elusive quasars.

• 6:27Speaker 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.

• 6:43Regina 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.

• 7:01Speaker 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.

• 7:14Regina Barber?

  And as one of the only women, she was very concerned about proving she was capable of that real work.

• 7:21Speaker 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.

• 7:39Regina 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.

• 7:54Regina Barber?

  And another.

• 7:55Speaker 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.

• 8:06Speaker 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.

• 8:35Regina 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.

• 8:46Speaker 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.

• 9:11Regina Barber?

  But she kept at it, and finally, she detected pulses again, this time in a string.

• 9:17Speaker 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

• 10:02Speaker 02

  at this very fast rate of one and a third seconds?

• 10:05Regina 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.

• 10:43Regina Barber?

  After Jocelyn made her landmark discovery, she married Martin Burnell, and her career took a turn.

• 10:49Speaker 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.

• 11:14Regina Barber?

  Peculiar because with each move, she looked for a new astronomy job.

• 11:18Speaker 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.

• 11:29Regina Barber?

  And so the work wasn't always in radio astronomy, the field where she made her name unmarried.

• 11:35Speaker 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.

• 11:59Regina Barber?

  Today, pulsars allow astronomers to measure cosmic distances, look for gravitational waves, and search for planets beyond our solar system.

• 12:08Speaker 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.

• 12:44Regina Barber?

  Thanks, as always, to you listeners for tuning in. And we asked you for some of your favorite space facts.

• 12:51Speaker 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.

• 13:08Speaker 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.

• 13:25Regina 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.

• 13:54Speaker 03

  Stay tuned for the following announcements and messages from our sponsors.