More than a hundred years ago an extraordinary mechanism was found by sponge divers at the bottom of the sea near the island of Antikythera. It astonished the whole international community of experts on the ancient world.
For decades, scientific investigation failed to yield much light and relied more on imagination than the facts. However research over the last half century has begun to reveal its secrets. It dates from around the end of the 2nd century B.C. and is the most sophisticated mechanism known from the ancient world. Nothing as complex is known for the next thousand years! The Antikythera Mechanism (wikipedia) is now understood to be dedicated to astronomical phenomena and operates as a complex mechanical “computer” which tracks the cycles of the Solar System.
Using nothing but an ingenious system of gears, the mechanism could be used to predict the month, day and hour of an eclipse, and even accounted for leap years. It could also predict the positions of the sun and moon against the zodiac, and has a gear train that turns a black and white stone to show the moon’s phase on a given date. It is possible that it could also show the astronomical positions of the planets known to the ancients: Mercury, Venus, Mars, Jupiter and Saturn.
The Antikythera mechanism wasn’t just a scientific tool – it also had a social purpose. The Greeks held major athletic competitions (such as the Olympics) every two or four years. A small dial within the Metonic dial showed the dates of these important events. Read more here, here or here and go here or here to see videos about the machine.