Meet The 2,000 Year Old Computer You Have Never Heard Of

                  
                       TheAntikythera mechanism picture courtesy of UK Guardian science

Antikythera mechanism is an ancient mechanical computer designed to calculate astronomical positions. It was recovered in 1900–1901 from the Antikythera wreck, but its significance and complexity were not understood until a century later. The construction has been dated to the early 1st century BC. Technological artifacts of similar complexity and workmanship did not reappear until the 14th century, when mechanical astronomical clocks were built in Europe.

                                    
                                                Picture courtesy of Wikipedia

Jacques-Yves Cousteau visited the wreck for the last time in 1978, but found no additional remains of the Antikythera mechanism. Professor Michael Edmunds of Cardiff University, who led the most recent study of the mechanism, said: "This device is just extraordinary, the only thing of its kind. The design is beautiful, the astronomy is exactly right. The way the mechanics are designed just makes your jaw drop. Whoever has done this has done it extremely carefully ... in terms of historic and scarcity value, I have to regard this mechanism as being more valuable than the Mona Lisa"

The mechanism is the oldest known complex scientific calculator. It contains many gears and is sometimes called the first known analog computer, although its flawless manufacturing suggests that it may have had a number of undiscovered predecessors during the Hellenistic Period. It appears to be constructed upon theories of astronomy and mathematics developed by Greek astronomers. It is estimated to have been made around 100 BC. In 1974, Yale University Professor Derek de Solla Price concluded from gear settings and inscriptions on the mechanism's faces that the mechanism was made about 87 BC and lost only a few years later.

It is believed to be made of a low-tin bronze alloy (95% copper, 5% tin), but the device's advanced state of corrosion has made it impossible to perform an accurate compositional analysis.

All of the mechanism's instructions are written in Koine Greek, and the consensus among scholars is that the mechanism was made in the Greek-speaking world. One hypothesis is that the device was constructed at an academy founded by the Stoic philosopher Posidoniu on the Greek island of Rhodes, which at the time was known as a center of astronomy and mechanical engineering; this hypothesis further suggests that the mechanism may have been designed by the astronomer Hipparchus, since it contains a lunar mechanism which uses Hipparchus's theory for the motion of the Moon. However, recent findings of The Antikythera Mechanism Research Project suggest that the concept for the mechanism originated in the colonies of Corinth, which might imply a connection with Archimedes.

It was discovered in a shipwreck off Point Glyphadia on the Greek island of Antikythera. The wreck had been found in October 1900 and divers had retrieved numerous artifacts, most of them works of art, which had been transferred to the National Museum of Archaeology for storage. On 17 May 1902, archaeologist Valerios Stais was examining the finds and noticed that one of the pieces of rock had a gear wheel embedded in it. Stais initially believed it was an astronomical clock, but most scholars considered the device an anachronism, too complex to have been constructed during the same period as the other pieces that had been discovered. Investigations into the object were soon dropped until English physicist Derek J. de Solla Price became interested in it in 1951.

It is not known how it came to be on the cargo ship, but it has been suggested that it was being taken to Rome, together with other treasure looted from the island, to support a triumphal parade being staged by Julius Caesar.

The device is remarkable for the level of miniaturization and the complexity of its parts, which is comparable to that of 19th-century clocks. It has more than 30 gears, although Michael Wright (see below) has suggested there may have been as many as 72 gears, with teeth formed through equilateral triangles. When a date was entered via a crank (now lost), the mechanism calculated the position of the Sun and Moon or other astronomical information, such as the locations of planets. Since the purpose was to position astronomical bodies with respect to the celestial sphere, in reference to the observer's position on the Earth, the device was based on the geocentric model.

The mechanism has three main dials, one on the front, and two on the rear. The front dial has two concentric scales. The outer ring is marked off with the days of the 365-day Egyptian calendar, or the Sothic year, based on the Sothic cycle. Inside this, there is a second dial marked with the Greek signs of the Zodiac and divided into degrees. The calendar dial can be moved to compensate for the effect of the extra quarter day in the solar year by turning the scale backwards one day every four years. A 365¹⁄₄-day year was used in the Callippic cycle about 330 BC and in the Decree of Canopus in 238 BC.

The front dial probably carried at least three hands, one showing the date, and two others showing the positions of the Sun and the Moon. The Moon indicator is adjusted to show the first anomaly of the Moon's orbit. It is reasonable to suppose the Sun indicator had a similar adjustment, but any gearing for this mechanism (if it existed) has been lost. The front dial also includes a second mechanism with a spherical model of the Moon that displays the lunar phase.