Antikythera Mechanism

The Antikythera Mechanism is the world’s oldest known geared device dating from c. 87 BCE.
It is an ancient computer found by divers in the Antikythera Shipwreck off the Greek Island of Antikythera between 1900-1901.

The device is currently housed in Room 38 of the National Archeological Museum of Athens along with a reconstruction.

It is estimated to have been constructed around 87 BCE and lost shortly after. Pottery and coins from the wreck are dated to around 65 BCE.
It has over 30 gears and by rotating a crank that showed a date, the positions of the Sun, Moon and the Five known Planets could be predicted.
It also predicted the Solar Eclipse and the Lunar Eclipse, using the Saros Cycle, and the date of the Olympic Games.

Cicero
- In his De Re Publica, Cicero refers to an Orrery which predicts the positions of the Sun and the Moon and the eclipses of both, and also the five known Planets of that time:
Archimedes
- Cicero points out that the Orrery was known to be one of two similar devices invented by Archimedes and brought to Rome by the Roman General Marcus Claudius Marcellus, after the defeat of the city of Syracuse in 212 BCE.

Derek J. De Soller Price

From 1951, the British science historian Derek J. De Soller Price studied the mechanism and in 1974 published ‘Gears from the Greeks: the Antikythera mechanism, a calendar computer from circa 80 BCE’
Price set up the Antikythera Research Project to attempt to solve the way the device functioned and created an International team of scholars.
Price succeeded in getting the device x-rayed, revealing 27 gears hidden inside the device.

Michael Wright

Michael Wright was a former curator of mechanical engineering at the Science Museum in London.
He had at the same time, but independently, been constructing his own model of the Antikythera Mechanism, gearwheel by gearwheel, but using a different approach.

The 19 year solar cycle and the 235 moon cycle.
In 19 solar years, there are 254 orbits of the moon around the Earth. Price discovered a 127 toothed gear, which is half of 254.
The x-rays revealed toothed gears with teeth numbered with Prime Numbers.
The gears had the following numbers of teeth:
- 19 for the solar cycle.
- 127 (half of 254 lunar cycles in 19 years).
- 223, this Gear predicted future Eclipses to the day and the hour.
By placing hands on the gears, which rotated over a clockface with markings, it would have been possible to see the positions of the Seven Classical Planets (Sun, Moon and the Five known Planets) and to predict Eclipses.

Antikythera, Greece