A corroded lump from an ancient shipwreck turned out to be a pocket-sized model of the heavens.
Divers recovered the bronze fragments near the Greek island of Antikythera in 1900–01. For decades, they looked like little more than scrap. X-rays and later detailed scans revealed tightly packed gears and inscriptions: the remains of a hand-operated astronomical instrument, probably made in the second or first century BCE.
Turn its crank, researchers infer, and linked dials could track cycles of the Sun and Moon, predict eclipses, and mark calendars or festival dates. Some parts are missing, so scholars still debate how the device represented the planets and where it was built. It was not a modern computer in miniature, but it did turn mathematical patterns into moving metal.
Imagine winding a machine to see when the sky would repeat itself. What other kinds of knowledge might ancient craftspeople have hidden in gears?