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Clocks ... and the Antikythera Mechanism

June 10, 2020

Today with atomic clocks and GPS, time and place are taken for granted.

In the past, with only analog technology, time and place required mechanical gearing. Below is a recreation of the Antikythera mechanism. The original Antikythera Mechanism was discovered in a shipwreck off the Greek island of Antikythera (hence its name) in 1902; and, dates from the 2nd or 3rd Century BC.

The device is a celestial calendar. The big hand is the moon. It is adorned with a black and white marble. As the big hand rotates, representing a month, the marble revolves showing the phases of the moon.

The other six hands are the Sun and five visible planets. As the moon rotates, these also rotate so that, over the course of 120 years, they map out the relative positions of the Sun and planets in the sky. These are all based on the ancient Egyptian calendar, transliterated on the device into classical Greek.

A DEMONSTRATION:

 

Inside the mechanism are gears. They create the cycles (and epicycles) of the seven moving stars.

On the rear of the box are two other hands. These indicate (or predict) solar and lunar eclipses.

It is an amazingly complex, although not terribly accurate mechanism. Possibly more for amusement than for anything like navigation on the high seas,

For centuries, the problem of navigation on the great oceans of the world was one of longitude. Latitude (or, one's north-south position) was relatively easy to determine from the angle to the Sun (the modern instrument for doing this is the sextant).

But, longitude was a tougher problem. All kinds of ideas were considered. For example. dead reckoning. That is, determine your direction and distance from a known location, usually involving an estimate of speed and time of travel. This was not very accurate.

In theory, longitude would be easy with an accurate clock. Compare local time at noon to time in London as kept on the clock. But, who could make an accurate clock for a ship being tossed about on the seas? The British government offered a prize to an inventor of such a clock.

The made for television 2000 movie Longitude tells the story of this inventor.

One of the more famous clocks in the world is the Rathaus-Glockenspiel at Munich, in the town plaza. There, at the appointed time, the clock not only strikes the hour, but life-size mechanical dolls recreate two scenes from the 16th Century. The first is the marriage of a prince. The second is the coopers dance.

In 1517 the Black Death visited Munich. The people were paralyzed with fear. To encourage the people of the town, the coopers danced through the street to bring joy and courage to the people. It is something we should consider recreating today while, of course, maintaining social distancing.

Author
Clifford F. Thies is the Eldon R. Lindsay Professor of Economics and Finance at Shenandoah University. He received his Ph.D. in economics from Boston College.
cthies@su.edu

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