In 1993, astronomers spotted a comet that looked like a glowing string of pearls, not orbiting the sun but trapped by Jupiter's gravity on an unavoidable collision course. This episode tells the story of Comet Shoemaker-Levy 9, the first time humanity directly observed a collision between two solar system bodies, an event that gave us a free look inside a gas giant and reshaped how we view our planet's safety.

We explain how Jupiter's enormous Hill sphere captured the comet, how the Roche limit tore it into 21 fragments, and the logistical challenge of observing impacts on Jupiter's far side, aided by the Galileo spacecraft and the planet's fast rotation. We cover the searing fireballs, the Earth-sized scars, the surprising chemistry the impacts revealed, and the debate over whether Jupiter acts as a cosmic shield or a slingshot.

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