Antikythera Mechanism – 150 BCE
The Antikythera Mechanism was recovered from an ancient shipwreck that was discovered in 1901. The heavily crusted artifacts were revealed to have a clockwork mechanism which has only recently become understood. It took years of research and studying Babylonian records of eclipses to confirm that the Antikythera Mechanism was the world’s first computer.
The Antikythera Mechanism features a fixed ring dial on the front face that represents the ecliptic, the twelve zodiacal signs marked off on equal 30 degree sectors. This is similar to the Babylonian method of assigning 1/12 of the ecliptic to each zodiac sign despite the fact that the constellation boundaries were variable. Outside of the dial the device features a ring that rotates and is marked off with the days and months of the Egyptian calendar.
The Antikythera Mechanism was about the size of a clock with a large circular face on the front and a knob on the side for winding the mechanism forward or backward. As the knob was turned at least seven different hands would move on the face and they would display the celestial time. There was one hand for the moon, one hand for each of the 5 planets that the Greeks were able to see, and one for the sun. The device was able to show not only which stars rose and set on any given date but also the phases of the moon.
The device was incredibly complicated and though the pieces found give instruction and ideas about how it worked, scientists and historians can only guess at the complicated arrangement of gears that must have gone into it. Some suggest that the Greeks used epicycles to show the movement of Mars while others believe that it would have been beyond the ability of the ancient Greeks. A full model of the Antikythera Mechanism was created and found to not be entirely accurate based on today’s knowledge but it fits the knowledge of the Greeks at the time.