Paul Dirac was so quiet that his Cambridge colleagues invented a unit of measurement — the “dirac,” defined as one word per hour. But behind that legendary silence was one of the most powerful minds in the history of physics. His equation predicted the existence of antimatter years before it was discovered in a laboratory, and his contributions to quantum mechanics rank alongside those of Einstein and Bohr.

This episode traces Dirac from his emotionally brutal childhood in Bristol through his revolutionary work at Cambridge, the Dirac equation that stunned the physics world, and the discovery of the positron that proved him right.

• Dirac’s painfully repressed childhood and the domineering father who shaped his silence
• The Dirac equation — the mathematical prediction of antimatter that nobody believed at first
• The discovery of the positron by Carl Anderson that vindicated Dirac’s theory
• Why Dirac is considered the physicist’s physicist despite being virtually unknown to the public