Technology, Connected - The Star That Fooled Astronomers

Episode Date: November 26, 2025

What makes neutron stars so fascinating that they once fooled astronomers into thinking they were aliens?1967: PhD student Jocelyn Bell Burnell discovers repeating radio pulses from space using a homemade array of wooden poles and copper wire. Regular. Precise. Unnatural.They called it LGM-1. Little Green Men.It wasn't aliens. It was something stranger: neutron stars. The densest objects in the universe. A teaspoon weighs a billion tons.Katia Moskvitch—science journalist and author—joins us to explore pulsars, cosmic mysteries, and why Bell Burnell's supervisor got the Nobel Prize instead of her.We talk about:- Why neutron stars were only theoretical for decades- Who first imagined their existence- How Bell Burnell built the radio telescope that changed astronomy- Why the discovery was almost dismissed as interference- What pulsars are (neutron stars spinning hundreds of times per second)- How they're used as cosmic lighthouses for navigation- The Nobel Prize controversy (her work, his award)- Whether she was robbed—or if the system worked as designedNeutron stars are stellar corpses. When massive stars explode, their cores collapse into objects 20 kilometers wide but heavier than the sun. They spin so fast they bend spacetime. Their magnetic fields are quadrillion times stronger than Earth's.Bell Burnell discovered them. But the 1974 Nobel Prize went to her male supervisor and another male colleague. She's never publicly complained. Others have.The question: Is this science's greatest injustice? Or does the Nobel Prize honor theory over observation—mentors over students—by design?This episode is about discovery, recognition, and what we choose to honor.---Guest: Katia Moskvitch, Science Journalist, AuthorTopics: Neutron stars, pulsars, astronomy, Nobel Prize, Jocelyn Bell Burnell, scientific discovery, recognitionCheers,Mark & Jeremy--Other ways to connect with us:⁠Listen to every podcast⁠Follow us on ⁠Instagram⁠Follow us on ⁠X⁠Follow Mark on ⁠LinkedIn⁠Follow Jeremy on ⁠LinkedIn⁠Read our ⁠Substack⁠Email: [e-mail]

So Joyce in Belbrinelle, I met her. Actually, she's a fantastic lady, very funny, super approachable. And at the time, the year was 1967, right? And that's when we discovered the first pulsar. Well, she discovered the first pulsar. Her supervisor got a Nobel Prize for it a few years later. She didn't, which in my opinion is super unfair. She's very cool about it, though.

Yeah, she just kind of. says that that was the time, but I think she definitely should have forgotten the Nobel Prize. The way it happened is very interesting as well, because so up until 1967, when she found the first pulsar, neutron stars were fully theoretical objects. And just to explain maybe what neutron stars are, first of all, for those who probably heard the name but don't really know what they are, I personally find them super fascinating. I know black holes are all over the place and everybody loves. I hope not.

But neutron stars are, as I think I mentioned in the beginning, right, that they are the densest matter that we can find in the universe. So like the final bus stop before the black hole. And they pop into existence after stars die and not just any star, but very massive stars. So for example, our sun, when our sun will die, it will be actually quite boring. Because what will happen, it will first in the next five billion years or so, it will exhaust its nuclear fuel.

When hydrogen nuclei basically fuse together, produce energy, that's why stars burn. That's why we see them in the sky. well you know once the nuclear fuel will be exhausted fully then the star will our sun will kind of swell up at first to become a red giant and eat up mercury Venus and unfortunately Earth as well we won't be there anymore but you know very sad fate and the outer layers of the sun will become just a planetary nebula but the core of the sun will become this very small object called white dwarf which will be the size of the earth, but very, very massive. So actually also quite massive, not as massive as neutron stars, but still, like imagine the mass of the sun, you put it in the object, the size of the earth,

and that's the white dwarf. White, because it's very, very hot at first, so we see this white light kind of radiating, you know, when it's super hot, then we can see the entire spectrum, all the colors as white light. And then, this time, it will become black and fade into oblivion,

and we will become a black dwarf and we will never be able to detect our sun ever again if we were to detect it from somewhere else. So that's the fate of the sun and rather boring deaths, but if you look at stars that are

much more massive, more than eight times more massive than the sun to be specific, then once hydrogen fuel is exhausted, what happens is then when kind of these lighter atoms fuse together, they form

heavier and heavy elements. So from hydrogen we get helium, from helium we get carbon, then we get oxygen and neon, magnesium, silicon, I think afterwards, and finally we get to iron. So all of this kind of they fuse, they give up energy, the star continues to live,

and then at some point when it gets to iron, well, iron actually needs energy and it doesn't, you cannot create energy by fusing iron nuclei. It doesn't happen. Iron is like the end point here of nuclear fusion. So what happens then, you know, when the star is stable and you have this pressure from nuclear fusion counteracting the pressure of gravity, well, if you don't have fusion anymore, then basically gravity starts being the only energy source at this point. The core starts to shrink

and there's no more resistance to counteract the gravity and everything just goes boom. So protons and electrons get squeezed together and become neutrons. So there are a lot of neutrons. And the resulting object is this core, which is the neutron star. We see the supernova explosion all around because we can see, we can detect it in optical, of course, and it's super, super bright, can outshine a galaxy. There are about, I think, two or three of these supernova explosions, that take place in 100 years or so in Milky Way alone.

so stars die pretty frequently. And the neutron star that stays behind is this fascinating tiny object of about 20 kilometers across. So if you imagine a city, I don't know the size of Chicago or something, and you curl it up into a ball. And so, yeah, 20 kilometers across and you put all the mass of the sun into that tiny sphere. A sun massively bigger than our sun.

It could be one to three solar masses. that's the mass that could be shoved into a tiny 20-kilometer sphere, which is a neutron star. Anything bigger and it will collapse into a black hole. So to remain stable, it has to have this very specific kind of mass. And it spins and it travels through space at high speed. So that's your neutron stars. And we didn't know they existed for real. They were theoretical for quite some time before Joycelin discovered them.

I think the first time they were theorized was in 1934 by Franz Twiki and Walter Badd. And those two guys, they just kind of came up with this idea, very correct idea, that supernova were due to stellar tests and neutron star would remain. But the problem was it was 1930s and, you know, there were other problems at the time. So even Oppenheimer, he actually worked on neutron stars quite a bit before. he got distracted by atomic bomb project and pulled in a totally different direction. He was the one who came up with the upper limit of the neutron star before it collapsed into black hole. So he did some really pretty important work.

But still, it was again mathematical, theoretical. And then finally in 1967, back to Joyce Lynn, she was a PhD student in Cambridge working with her supervisor, Anthony Huyvesh, who was super passionate about discovering more quasi. quasars. Quasers are these active galactic nuclei that are super, super luminous objects in the sky, and they are powered by supermassive black holes inside galaxies. And we had just discovered them at the time, so everybody was like, wow, super cool, let's look for more. And that's what Joycelin was doing. She was putting wooden poles into the ground and connecting them with copper wire to create this quite primitive-looking array. so an observatory made out of wooden poles and copper wire effectively.

I actually went there. It's still there. You can still see the wooden poles. Copper wire had been stolen and sold, unfortunately. But the wooden poles are still there. So anyway, she was looking through data one day and looking for these quasars. And suddenly she saw a very weird signal that was repeating, just a peak, and it was repeating a few times. And she thought, what is this?

That's not a normal quays. is our signature. So she went to her supervisor, they examined it, and they thought those were aliens, like for real. They were really, they really thought for quite a few months that those were aliens signaling from somewhere in the galaxy, signaling the earth. And they kept it super hush-hush. They didn't tell anybody about the discovery, because she discovered three more. So she discovered four in full, in total of this. A lot of aliens, oh dear. Yeah, exactly. And so she named them, they named them LGMs, little green men. So those were the names for the for the first signals that they got. And she was actually pretty upset. And when I was

thinking about, you know, today's interview, today's podcast, I even bookmarked here in my book, I'm going to read you a short quote from her because she said she was about to defend her PhD thesis in about six months or so at that time. And so she said, why would little green man be using a daft technique signaling to what was and probably still is a rather inconspicuous planet? So that tells you about her sense of humor, but also, you know, what she thought about the project at the time. But of course it turned out to be not aliens and they knew.

So they just analyzed and reanalyzed the data. And finally, the paper was published in February, 1968, and they said that it was indeed neutron stars. And that was just the bombshell discovery and beginning of Pulsar astronomy. It was super cool. All right. So what did we just watch right there? We watched Thinking on Paper, bite-sized,

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