In its prime, about 2,100 years ago, the Antikythera (an-ti-KEE-thur-a) Mechanism was a complex, whirling, clockwork instrument comprising at least 30 bronze gears bearing thousands of interlocking tiny teeth. Powered by a single hand crank, the machine modeled the passage of time and the movements of celestial bodies with astonishing precision. It had dials that counted the days according to at least three different calendars, and another that could be used to calculate the timing of the Olympics. Pointers representing the stars and planets revolved around its front face, indicating their position in relation to Earth. A tiny, painted model of the moon rotated on a spindly axis, flashing black and white to mimic the real moon’s waxing and waning.
The sum of all these moving parts was far and away the most sophisticated piece of machinery found from ancient Greece. Nothing like it would appear again until the 14th century, when the earliest geared clocks began to be built in Europe. For the first half century after its discovery, researchers believed that the Antikythera Mechanism had to be something simpler than it seemed, like an astrolabe. How could the Greeks have developed the technology needed to create something so precise, so perfect — only to have it vanish for 1,400 years? By Sarah Kaplan