In 1965, scientists opened a sealed fragment of the Orgueil meteorite that had fallen in France a century earlier and found a plant seed inside, apparently beneath an intact fusion crust. It was a hoax: a European rush seed glued in with water-soluble adhesive and disguised with coal dust. This episode uses that elaborate 1860s forgery as the doorway into panspermia, the hypothesis that life or its precursors were delivered to Earth from space, and explains the scientific traffic jam that made the idea so tempting: a molten early Earth born sterile, Darwin's evolution with no explanation for the first ancestor, and Pasteur and Tyndall disproving spontaneous generation.

We walk through the major mechanisms proposed since Lord Kelvin's 1871 suggestion. Svante Arrhenius's radiopanspermia used starlight pressure to push spores between stars, bu ...