https://www.youtube.com/watch?v=kGY4t683Xro

Hosted by: Fraser Cain ( @frasercain ) and Dr. Pamela L. Gay ( @CosmoQuest )

Streamed live on Dec 22, 2025.

Shortly after the big bang there were almost exactly the same amounts of matter and antimatter in the Universe, but there was just enough of a difference that we live in a matter-dominated Universe. But it didn't have to be that way! Explaining this mystery has been one of the great mysteries in astronomy, and today we'll see if there's been any progress! Why is the Universe the way it is? Specifically, why is it made mostly of matter? This is the question we'll look at today!

This show is supported through people like you on Patreon.com/AstronomyCast

In this episode, we'd like to thank: Andrew Poelstra, BogieNet, Brian Cagle, Burry Gowen, David, David Rossetter, Ed, Gerhard Schwarzer, Jason Kwong, Jeanette Wink, Michael Purcell, Sergey Manouilov, Siggi Kemmler, Sérgio Sancevero

We've added a new way to donate to 365 Days of Astronomy to support editing, hosting, and production costs.

Just visit: https://www.patreon.com/365DaysOfAstronomy and donate as much as you can!

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The 365 Days of Astronomy Podcast is produced by the Planetary Science Institute. http://www.psi.edu

Visit us on the web at 365DaysOfAstronomy.org or email us at [email protected].