Antikythera Mechanism: the world’s oldest known computer

A computer reconstruction of the Antikythra mechanism

The Antikythera is an ancient greek machine that is often referred to as the “world’s first analog computer”. Archaeologists predict that the machine was built between 200 and 80 BC. It was a highly complex system of gears that was capable of making astronomical and astrological predictions decades in advance.- eg. positions of the Sun and Moon, phases of the Moon, eclipses, etc.


121 years ago (in 1900), captain Dimitrios Knotos and his diving crew discovered the Antikythera shipwreck. The wreck was found at a depth of 45 meters from point Glyphadia on the Greek island of Antikythera. In 1901, a huge chunk of bronze metal along with other ancient artifacts was retrieved from the shipwreck. The retrieved item was sent to the National Museum of Archaeology in Athens for analysis. One year after its retrieval in 1902, it was identified that the bronze artifact contained gears. it was assumed to be only a simple astronomical clock and was forgotten for a few decades.

Investigations on the artifact did not restart until 1951 when Derek J. de Solla Price, a professor from Yale University got interested. in 1971, He, together with greek physicist Charalampos Karakalos produced X-ray and Gamma-ray images of the artifact and published their findings in the 70-page research paper- “Gears from the Greeks : the Antikythera mechanism, a calendar computer from ca. 80 B.C“.

Structure and operation:

Computer reconstruction of the gear system inside the Antikythera mechanism credit:

The level of complexity of the machine was very remarkable (comparable to that of 14th-century astronomical clocks). It had at least a system of 30 gears. The gears were housed in a rectangular frame that had a front face and a rear face.

The above image shows the front face of the mechanism. The two hands show the position of the Sun and Moon. credit:

On the front face is a large dial with 365 days of the year (according to the Egyptian solar calendar). Inside the Dial are the 12 zodiac signs (each separated by a 30-degree angular displacement). The mechanism was operated by turning a handle (the handle is lost) that would turn two hands on the dial- these hands indicate the position of the Sun and Moon- and a small sphere on one of the hands also indicated the phase of the moon.

The above image shows the rear face of the machine. It has two spirals, one indicates the Lunar and Solar cycles while the other indicates eclipses of the Suna and Moon. credit:

On the rear end are two spirals. One spiral showed the Lunar and Solar cycles over a period of 19 years and the other spiral showed the eclipses of the Sun and Moon.

In addition to the above, it was discovered in 2008 that the machine was also used to decide which cities would host future Olympics games (held every 4 years). Many archaeologists also believe that it was used for navigational purposes and also to trace the path of the planets.

There are many questions left to be answered about this amazing machine. For example, no one knows how the device exactly worked, we have no idea who built this machine or the exact purpose of the machine- was it a toy, a teaching tool, or something else? These discoveries make you wonder what other ancient technologies have been lost and whether they will ever be discovered…


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