Welcome to Quantum Magazine's podcast. Each episode we bring you stories about developments in science and mathematics. I'm Susan Vallett.

Anytime astronomers figure out a new way of looking for magnetic fields in ever more remote regions of the cosmos.

Inexplicably, they find them.

And ultimately, if they date back to the Big Bang, they could help solve a mystery.

Magnetic fields surround Earth, the Sun, and all galaxies.

Twenty years ago, astronomers started to detect magnetism permeating entire galaxy clusters,

including the space between one galaxy and the next.

Invisible field lines swoop through intergalactic space, like the grooves of a fingerprint.

Last year, astronomers finally managed to examine a far sparser region of space, the expanse between galaxy clusters. There, they discovered the largest magnetic field yet.

Ten million light years of magnetized space spanning the entire length of this filament of the cosmic web.

A second magnetized filament has already been spotted elsewhere in the cosmos using the same techniques.

Federica Giovanni is with the National Institute for Astrophysics in Italy.

She led the first detection.

I think that probably there are also other systems, other filaments, which make, I hope that

there are other systems which may present this kind of ination. But probably we are just at the

start of the study. We are just looking at the peak of the eye there, probably.

The question is, where did these enormous magnetic fields come from?

Franco Wazza, an astrophysicist at the University of Bologna, has thought about that.

He makes state-of-the-art computer simulations of cosmic magnetic fields.

Please excuse the reporter's typing.

It's clearly cannot be related to the activity of single galaxies or single explosions

or, I don't know, galactic winds from supernovae. This goes much beyond that. So it should be

...