Decoding an ancient computer.

The article discusses research that has revealed how the Antikythera mechanism, which is a unique astronomical calculator, modeled lunar motion and predicted eclipses. According to the authors, archaeologists discovered in 1901, but had anticipated its true power. Topics include how advancements in imaging tools have enabled researchers to reconstruct how the device worked and what inscriptions on the mechanism, which was built in second-century B.C. Greece, may suggest about who built it. INSETS: Where Was It From?;Anatomy of a Relic;How to Predict an Eclipse.