Something Weird Happens When E=−mc²

In this video, Derek Muller dives into Paul Dirac’s journey from the failure of the Schrödinger equation to his groundbreaking Dirac equation, which surprisingly allowed for “negative energy” solutions. Along the way we meet the brilliant and eccentric Dirac, learn how Heisenberg’s uncertainty principle plays a role, and discover how Dirac’s math predicted the existence of the positron—an anti-electron that behaves as if it’s traveling backward in time.

Beyond the math, the video explores the wild idea of an entire “anti-world,” where antimatter counterparts mirror our universe. Packed with historical anecdotes, expert insights from Graham Farmelo and Cumrun Vafa, and archival footage from FSU and Caltech, it’s a fascinating look at how a strange equation opened the door to the anti-universe.

Watch on YouTube