This episode was made in partnership with the Kavli Prize.

The Kavli Prize honors scientists for breakthroughs in astrophysics, nanoscience and neuroscience, transforming our understanding of the big, the small and the complex. [♪ INTRO] In 2002, a scientist named Conny Aerts was about to make a breakthrough. She just didn’t know it yet.

She was on Christmas break with family, doing some light reading. If you consider over 20 years of data from one of Chile’s La Silla telescopes light reading. Aerts struck gold by focusing on one star, elegantly named HD 129929.

She saw that the light from this star was getting dimmer, then brighter in a regular pattern. The star was wobbling, but not in a way scientists had observed before! Aerts was about to become one of the first researchers to study a new kind of physics in stars.

And today, she’s one of the world’s experts in asteroseismology, and a winner of the 2022 Kavli Prize in Astrophysics. Aerts was born to a working-class family in northern Belgium, and her childhood in the countryside gave her plenty of chances to stargaze, but not the easiest route to academia. There weren’t many opportunities to talk science… or college admissions.

Still, some of her teachers saw her potential, and helped her become the first in her family to go to university. She studied math at Antwerp University, then followed her passion to a PhD in astrophysics at KU Leuven. There, she studied how stars evolve over time, and what they look like on the inside.

Most stars are so far away, we can barely see their outsides. So, how can we possibly see what’s going on inside them? That’s where asteroseismology comes in.

It involves figuring out what’s going on inside stars by looking at how waves and oscillations travel through them. As giant balls of constantly churning plasma, stars are incredibly dynamic places. Waves of pressure called acoustic modes bounce around inside them, making material like hydrogen and helium slosh to and fro.

It’s like making waves on the universe’s biggest guitar string, and it can cause an entire star to wobble just a little bit, in a literal starquake. That can lead to tiny flickers in the star’s brightness that happen at a fixed rate. For example, it might go from bright to dim to bright again every thousand seconds.

And researchers can use that flickering pattern to figure out what a star’s insides probably look like. For instance, pressure waves bounce around differently in hydrogen plasma than they do in helium plasma. So, how a star flickers will depend, at least in part, on how much of each element it has.

But back to Professor Aerts! She became involved in asteroseismology during her PhD in the late 1980s. And in 2002, after getting a faculty position at KU Leuven, she made her first big breakthrough.

While on that fateful Christmas break, she noticed tiny, complex, and unusual flickers in the starlight from HD 129929. The flickers were at a lower frequency than you’d expect from acoustic modes in stars like the Sun, and only half of them seemed to be caused by the usual stellar material sloshing around. It was a different physical effect.

But what? The clue was that the star is about ten times as massive as our Sun. It’s so massive that the material inside the star could be pulled inwards by the star’s immense gravity.

Then, that material would be pushed outward by radiation expelled from the star’s core…and make the whole star ripple. By 2002, there had already been lots of research into the Sun’s interior, where we’d seen those acoustic pressure waves. But Professor Aerts became one of the earliest scientists to find these hypothetical gravity-based waves.

And that was just the beginning. A few years later, the big data era of asteroseismology began. Multiple space missions had launched that could detect these tiny ripples in starlight more easily, including NASA’s Kepler probe.

Aerts and her team went from studying a handful of stars, to supervising scans of hundreds of flickering stars found by Kepler. Overall, she’s been a major player in asteroseismology. In fact, in 2010, she literally co-wrote the textbook on it!

These days, her research mainly focuses on stellar evolution, working out how stars change over their lifetimes. For instance, the amount of helium in a star’s core changes throughout its life. And one way you can measure how much helium is in a star is by studying starquakes…how the material inside that star is churning.

So, scientists can calculate how much helium they think should be in a star’s core, based on their models, and then compare that to what the real-world wobbling says. If those numbers are different, it means astrophysicists need to update and improve their models of how stars evolve. And sure enough, Aerts found that those models need tweaking!

They weren’t predicting the right internal rotation rates, or the right amount of mixing of elements near a star’s core. So, Conny Aerts began her life looking up at the sky in the countryside, and now she’s spent decades understanding the inner workings of stars thousands of light-years away. Her career hasn’t just been limited to research, either.

Professor Aerts is also a major contributor to several European Space Agency missions, she’s won several major awards like the 2022 Kavli Prize, and she’s supervised over a hundred Masters, PhD, and postdoc researchers. Many of her former students have gone on to great careers in science themselves. After all, Professor Aerts knows a thing or two about finding hidden potential deep within.

This video was made in appreciation of Aerts’s work and in partnership with the Kavli Prize to highlight one of the laureates of the 2022 Kavli Prize in Astrophysics. The Kavli Prize honors scientists like Aerts for breakthroughs in astrophysics, nanoscience and neuroscience, transforming our understanding of the big, the small and the complex. This year, we’re partnering with the Kavli Prize to show off the awesome research done by winners of each of those Kavli Prizes.

Now that you’ve seen the astrophysics award, you can check out the research that earned a 2022 Kavli Prize in neuroscience. Thanks for watching! [♪ OUTRO]