World's first computer more complex than previously believed

A new study has revealed that the Greeks were able to predict eclipses and engineer a highly complex machine-sometimes called the world's first computer-at an earlier stage than believed.

The study also supports the idea that the eclipse prediction scheme was not based on Greek trigonometry (which was nonexistent in 205 B.C.)-but on Babylonian arithmetical methods, borrowed by the Greeks.

The researchers said that if the Antikythera mechanism did indeed use an eclipse predictor that worked best for a cycle starting in 205 BC, the likely origin of this machine is tantalizingly close to the lifetime of Archimedes.

Evans and Carman arrived at the 205 B.C. date using a method of elimination that they devised. Beginning with the hundreds of ways that the Antikythera's eclipse patterns could fit Babylonian records (as reconstructed by John Steele, Brown University) the team used their system to eliminate dates successively, until they had a single possibility.

The calculations take into account lunar and solar anomalies (which result in faster or slower velocity), missing solar eclipses, lunar and solar eclipse-s cycles, and other astronomical phenomena. The work was particularly difficult because only about a third of the Antikythera's eclipse predictor is preserved.

The study was published in the Archive for History of Exact Science.