A teaspoon of matter from the surface of a neutron star would weigh roughly a billion tons. These extraordinarily dense objects are the remnants of massive stars that ended their lives in catastrophic supernova explosions, leaving behind cores so compressed that electrons and protons merge into neutrons. This episode examines the formation of neutron stars, the unimaginable physics governing their surfaces and interiors, and the crucial role they play in creating the heaviest elements in the cosmos.

Beyond their staggering density, neutron stars manifest in bizarre and observable ways. The episode explores the discovery of pulsars by Jocelyn Bell Burnell, the rapid rotations of millisecond pulsars, and the terrifying magnetic fields of magnetars. It also traces the violent collisions between neutron stars, events that act as cosmic foundrie ...