In 1918, Arthur Stanley Eddington stood before a British military tribunal as a Quaker conscientious objector, risking imprisonment for refusing to fight. At the same time, he was championing a revolutionary theory smuggled out of enemy Germany through Dutch physicist Willem de Sitter. This episode follows the Cambridge astronomer, Plumian Professor and observatory director, who was one of the few people on Earth able to read the tensor calculus of general relativity, and the intervention by Astronomer Royal Frank Watson Dyson that turned an eclipse expedition into a matter of national prestige.

The hosts explain the physics at stake: Newtonian math predicted starlight bending by about 0.83 arc seconds near the Sun, while Einstein's 1915 theory predicted 1.75, roughly the width of a human hair seen from a mile away. They cover the rain-ruin ...