THE ANTIKYTHERA MECHANISM
How long ago was the earliest computer invented?
In 1900 sponge divers off the Aegean island of Antikythera discovered an ancient shipwreck on the seabed 150 feet below. In and around the ship, which sank some 2,000 years earlier, was a treasure trove so rich that divers continue to explore the wreckage today. Among the more recent finds are a flute, ceramic jugs, and a bronze armrest, possibly from a throne. But the most mysterious objects, which had been recovered in 1901, were misshapen pieces of bronze that were corroded in every shade of green. Behind the corrosion were gears with triangular teeth and a ring that resembled a protractor. They turned out to be fragments of a piece of machinery more sophisticated than anything that would be invented for another 1,000 years.
The fragments were sent to the Archaeological Museum in Athens, but it took decades for scholars to make sense of them. X-ray imaging from the 1970s to the 1990s provided important clues, and investigators decided that the device must have helped ancient Greek astronomers track the sun, moon, and planets with a high degree of accuracy. The device was dubbed the “Antikythera mechanism”; it was about the size of a mantel clock and appears to have been in a wooden case when the ship it was on went down. It had interlocking gearwheels that drove at least seven different hands and a handle for winding them backward and forward. The hands tracked the celestial time based on movements of the sun, moon, and five planets that were visible to the naked eye since ancient times. The device also indicated the moon’s phases and inscriptions showed the rising and setting of stars on particular dates. Another dial displayed the dates of major athletic events, including the Olympic Games. Around 80 pieces of the mechanism have now been recovered. Others may still rest at the bottom of the sea or have been destroyed. The tradition for making instruments such as the Antikythera mechanism may be much older than the one that was found. The Roman author Cicero described such a device made by Archimedes in the third century BC. Though it was not programmable, some regard this device as the first analog computer.