The Antikythera Mechanism

Not in the Pacific and not a voyage. But it is my favorite story from antiquity.

In 1901 in what was to become the first deep water ship excavation, a hardhat sponge diver was shocked to find a man standing serenely on the sandy bottom 150 feet below the surface near the Greek island of Antikythera. It turned out to be a marble statue from a trove of what proved to be one of the greatest treasure ships from ancient Mediterranea. This was no ordinary cargo of trade goods but appears to have been essentially an ancient FeDex shipment of specific items from about 60 BC. There were bronze and marble statues, fine ceramics, unique glassware, jewelry, coins, and a hunk of corroded metal just a bit smaller than a modern laptop.

The retrieved items went to the Athens Museum and for years the hunk of metal sat on a shelf with little study until 1959 until an X-ray machine was used. It was noted then that it appeared to be an astronomical clockwork of some sort. But in 1971 a researcher used a 3d X-ray machine to peer into the interior of the device and what he found rewrote our understanding of machinery from the ancient world.

Since 1971 the device has been continually probed for its secrets which it has given up using ever more powerful imaging tools. It’s only in the last months it was discovered to contain a set of written instructions with detailed descriptions of the Zodiac. The Mechanism has been called an analog computer or a calculator and consists of 37 moving parts including toothed gears, spindles and dials. Today there are countless models, animations and diagrams of the device.

The mechanism was originally housed in a wooden box with just 29mm clearance to accommodate all the nested gears and hollow spindles. How they were able to make concentric tubes as small as 3mm in diameter is still a mystery. When a crank mounted on the side was turned, a dial showing the positions of the five known planets and the Earth and Moon were displayed in motion. This kind of device is called an orrery. It could predict phases of the moon, eclipses both in the future as well as giving the dates for those in the past. It could even account for leap years.

It has been speculated that the position of the stars were of vital interest to the Greeks as they held the Olympic Games every four years and celestial locations are an essential part of their mythology.

All this, even though the maker put the earth in the center with the sun rotating around it (even though many Greeks didn’t think this was the case). There is no way to tell how accurate the device was because planetary science was imprecise. Also the gears were hand filed and the accuracy would decline when one cranked too far into the future. Sort of like our predictions about everything, right?

Ahhh, ok I guess we can build it.

The mechanism is the most studied ancient piece of technology and many mathematicians and archaeologists have spent their entire careers studying this object. It dates back to around 90-150 BC. Some researchers specialize in studying its method of manufacture and others are interested in the mathematics.

Archaeologists agree it had to have come from earlier iterations of simpler machines. So this device is called a prolepsis, ‘a thing jarringly out of time.’ Mentions of brass gears is nowhere to be found in ancient texts. Of course one problem is that there are essentially no texts. Virtually everything we know of ancient Rome and Greece comes from the centuries of repeatedly copied texts that scholars used to teach rhetoric after the fall of these societies. There is one record of an orrery from the workshop of Archimedes which was sent to Rome after having been found in his workshop in 212 BC after he was killed in the Siege of Syracuse. It was considered a great treasure by this the most famous engineer of all time. When General Marcus Claudius Marcellus conquered this Greek island (today’s Sicily) he gave explicit orders to not harm Archimedes but an officer found the scientist in his bath and killed him when he refused to get out of it. Or so the story goes.

No other devices would come close to using this technology until about 1,600 years later with the development of clocks and even they could only tell time. The late 17th century brought orreries, mechanical automatons and calculators once machining was up to the task.

The Antikythera mechanism is the oldest existing analog (non programmable) computer. Fun fact: The word ‘computer’ was initially used to refer to women (they were all women) who were hired to run large calculations of vote counts in political elections and at accounting firms. The women were called computers.

At least one Greek did build a programmable computer (made of wood with software and hardware) in Alexandria. You might think I’m exaggerating. But I am not. This man also invented a steam engine, coin operated vending machine, an automatic water fountain and the fire engine. All this in about 50 BC. And while we’re at it I’ll tell you about the first mathematician/philosopher who dreamed up the internet in in 1680. I’ll save these stories for a future article.

The lesson here is that if you find a hunk of rusted gears in an ancient wreck take it seriously. It ‘might be the Prince of Peace returning.’

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