If the universe were infinite, eternal and evenly filled with stars, classical physics says the night sky should glow like the surface of the Sun. This episode unpacks Olbers' paradox, using the infinite forest analogy and the concentric shell model to show why every line of sight should end on a star. The hosts explain why interstellar dust cannot save the argument, since over infinite time it would heat up and glow just as brightly, and trace the puzzle from Thomas Digges and Kepler through Halley, Cheseaux and Heinrich Wilhelm Olbers in 1823.

The surprising turn comes from Edgar Allan Poe, whose 1848 essay Eureka proposed that distant starlight simply has not had time to reach us, implying a universe with a finite age. Johann Heinrich von Madler and Lord Kelvin later gave that idea mathematical rigor. The episode then moves to the modern ...