Welcome to Quantum Magazine's podcast.

Each episode, we bring you stories about developments in science and mathematics.

I'm Susan Vallett.

For decades, astronomers have been perplexed by planetary magnetic fields.

Now, researchers are hoping observations of exoplanets could help us

understand magnetism better. That's next.

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In our own solar system, there's no rule that explains which worlds generate magnetic shields.

For example, Earth has one, but its sister world, Venus, does not.

Astronomers suspect that one of the best ways to understand the mysteries of magnetism might be to study

worlds orbiting other suns. By collecting a census of exoplanet magnetic fields, researchers could determine whether they are common features of other worlds.

Mary Knapp, who studies exoplanets at MIT's Hastack Observatory, says doing so would help put our solar system in context and resolve some abiding curiosities.

She says Earth versus Venus is a good example.

Earth and Venus are quite similar. They're similar in mass. The orbits are not that different.

They formed at the same time from the same protoplanetary disks, so the compositions can't be too wildly different.

It's been a challenge to build such a census and to even find exoplanet magnetic fields,

because these fields are faint and hard to detect.

But in April, two independent teams found what appears to be the signature of a magnetic field

produced by a rocky planet orbiting a small,

...