I saw this on MyHeritage shortly after it was posted – The World’s Oldest Known Computer Was Made by Ancient Greeks: https://blog.myheritage.com/2020/01/the-worlds-oldest-known-computer-was-made-by-ancient-greeks/
by Esther January 5, 2020
When we think of early computers, usually what comes to mind is punch cards and gigantic WWII-era machines that filled entire rooms. But humans have been using mechanical devices to make complex calculations for hundreds and thousands of years… and not just abacuses and slide rules, either. Some of our ancestors invented machines of astounding complexity, usually to assist them in calculating large distances and the movements of the stars and planets.
Though there are references to the existence of these devices from as early as 150 B.C.E. in ancient Greece, the oldest such device that’s been discovered is the Antikythera mechanism.
The Antikythera shipwreck
In the year 1900, fishermen diving for sponges noticed a bronze hand on the sea floor off the coast of the Greek island Antikythera. This led to the discovery of an ancient Roman shipwreck containing myriad treasures, such as fine sculptures, coins, jewelry, and ceramics. Among these artifacts was a lump of corroded bronze and wood that went ignored for the first 2 years as museum staff enthusiastically worked on the items of more obvious value.
In May 1902, however, an archeologist noticed a metal gear embedded in that lump. At first, he believed it was an astronomical clock, but that didn’t fit the dating of the other items in the wreck. The shipwreck seemed to have occurred sometime between 87 B.C.E. and 60 B.C.E., and astronomical clocks were first seen in the Middle Ages. So scientists abandoned further attempts to investigate the device until a British science historian, Derek J. de Solla Price, began studying it in 1951. 20 years later, he and a colleague took X-ray and gamma-ray images of the mechanism’s fragments and began to piece together its construction and functions. In recent years, scientists were able to use more advanced technology to analyze the inscriptions found on the device that provided instructions for its use.
What they found is a device of incredible ingenuity that was used to indicate the exact position of the sun and moon and lunar phase on a given date, as well as the date’s position in the Metonic cycle — and to predict lunar and solar eclipses.
How it worked
According to modern-day reconstructions, the Antikythera mechanism was a system of interlocking gears housed in a wooden box with two bronze faces on opposite sides and a small crank on one side. On one of the device’s faces, there was one dial with a pointer indicating the date on the Egyptian calendar and its position within the zodiac. Another dowel held a small sphere that turned on its axis, representing the moon shifting through its phases.
On the other side, there were two main dials. One of the dials represented the date’s position within the Metonic cycle. The Metonic cycle is a 19-year period that is a common multiple of the lunar and solar calendars — meaning, it can be used to align these calendars. It is still used today to regulate the Hebrew calendar, which incorporates lunar and solar components.
The other dial indicated lunar and solar eclipses expected during a given saros cycle. A saros is a period of 223 lunar months that can be used to predict eclipses.
Ahead of its time
Incorporating all these components, some of which were quite irregular, into a single mechanical device took an astounding level of complex knowledge. Price, the researcher who first pieced together the mechanism’s functions in the 1970s, believed that the mechanism was built in 87 B.C.E. and lost only a few years later. While the Byzantine and Islamic periods yielded their own inventions for similar types of calculations, it was not until the 14th century C.E. that devices of such complexity reappeared.