Something Weird Happens When E=−mc²

Ever wondered why flipping the sign on Einstein’s famous formula uncovers a whole “anti-world”? This Veritasium deep dive follows Paul Dirac as he wrestles with negative energy solutions—starting from the limits of the Schrödinger and Klein–Gordon equations, through Heisenberg’s uncertainty principle, all the way to the groundbreaking Dirac equation. Along the way, we meet the “strangest man in physics,” witness the prediction of the anti-electron (positron), and even entertain the wild idea of antiparticles traveling backward in time.

Packed with historical tidbits, expert insights from Graham Farmelo and Cumrun Vafa, and a peek at the saddest chapter in modern physics, this video unpacks how a theoretical hiccup turned into the discovery of an anti-universe. Whether you’re here for the science or the story, it’s a mind-bender that shows how one bold equation reshaped our understanding of reality—and spawned an entirely opposite mirror world.

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