The First Analog Computer: The Antikythera Device

Sponges are some 8,000 species of animals that grow in the sea that lack tissues and organs. Fossil records go back over 500 million years and they are found throughout the world. Two types of sponges are soft and can be used to hold water that can then be squeezed out or used to clean. Homer wrote about using Sponges as far back as the 7th century BCE, in the Odyssey. Hephaestus cleaned his hands with one - much as you and I do today.  Aristotle, Plato, the Romans, even Jesus Christ all discussed cleaning with sponges. And many likely came from places like the Greek island of Kalymnos, where people have harvested and cultivated sponges in the ocean since that time. They would sail boats with glass bottoms looking for sponges and then dive into the water, long before humans discovered diving equipment, carrying a weight, cut the sponge and toss it into a net. Great divers could stay on the floor of the sea for up to 5 minutes.  Some 2,600 years after Homer, diving for sponges was still very much alive and well in the area. The people of Kalymnos have been ruled by various Greek city states, the Roman Empire, the Byzantines, Venetians, and still in 1900, the Ottomans. Archaeologist Charles Newton had excavated a Temple of Apollo on the island in the 1850s just before he’d then gone to Turkey to excavate one of the Seven Wonders of the Ancient World: The Mausoleum of Halicarnassus, built by Mausolus - such a grand tomb that we still call buildings that are tombs mausoleums in his honor, to this day. But 1900 was the dawn of a new age. Kalymnos had grown to nearly 1,000 souls. Proud of their Greek heritage, the people of the island didn’t really care what world power claimed their lands. They carved out a life in the sea, grew food and citrus, drank well, made head scarfs, and despite the waning Ottomon rule, practiced Orthodox Christianity.  The sponges were still harvested from the floor of the sea rather than made from synthetic petroleum products. Captain Dimitrios Kontos and his team of sponge divers are sailing home from a successful run to the Symi island, just as they’d done for thousands of years, when someone spots something. They were off the coast of Antikythera, another Greek island that has been inhabited since the 4th or 5th millennia BCE, which had been a base for Cilician pirates from the 4th to 1st centuries BCE and at the time the southern most point in Greece. They dove down and after hearing stories from the previous archaeological expedition, knew they were on to something. Something old. They brought back a few smaller artifacts like a bronze arm - as proof of their find, noting the seabed was littered with statues that looked like corpses.  They recorded the location and returned home. They went to the Greek government in Athens, thinking they might get a reward for the find, where Professor Ikonomu took them to meet with the Minister of Education, Spyriodon, Stais. He offered to have his divers bring up the treasure in exchange for pay equal to the value of the plunder and the Greek government sent a ship to help winch up the treasures.  They brought up bronze and marble statues, and pottery. When they realized the haul was bigger than they thought, the navy sent a second ship. They used diving suits, just as those were emerging technology. One diver died. The ship turned out to be over 50 meters and the wreckage strewn across 300 meters.  The shipwreck happened somewhere between 80 and 50 BCE. It was carrying cargo from Asia Minor probably to Rome, sank not by pirates, which had just recently been cleared from the area but likely crashed during a storm. There are older shipwrecks, such as the Dokos from around 2200 BCE and just 60 miles east of Sparta, but few have given up as precious of cargo. We still don’t know how the ship came to be where it was but there is speculation that it was sailing from Rhodes to Rome, for a parade marking victories of Julius Caesar. Everything brought up went on to live at the National Museum of Archaeology in Athens. There were fascinating treasures to be cataloged and so it isn’t surprising that between the bronze statues, the huge marble statues of horses, glassware, and other Greek treasures that a small corroded bronze lump in a wooden box would go unloved. That is, until archaeologist Valerios Stais noticed a gear wheel in it.  He thought it must belong to an ancient clock, but that was far too complex for the Greeks. Or was it? It is well documented that Archimedes had been developing the use of gearwheels. And Hero of Alexandria had supposedly developed a number of great mechanical devices while at the Library of Alexandria.  Kalymnos was taken by Italians in the Italo-Turkish War in 1912. World War I came and went. After the war, the Ottoman Empire fell and with Turkish nationalists taking control, they went to war with Greece. The Ottoman Turks killed between 750,000 and 900,000 Greeks. The Second Hellenic Republic came and went. World War II came and went. And Kylamnos was finally returned to Greece from Italy. With so much unrest, archeology wasn’t on nearly as many minds.  But after the end of World War II, a British historian of science who was teaching at Yale at the time, took interest in the device. His name was Derek de Solla Price. In her book, Decoding the Heavens, Jo Marchant takes us through a hundred year journey where scientists and archaeologists use the most modern technology available to them at the time to document the device and publish theories as to what it could have been used for. This began with drawings and moved into X-ray technology becoming better and more precise with each generation. And this mirrors other sciences. We make observations, or theories, as to the nature of the universe only to be proven right or wrong when the technology of the next generation uncovers more clues. It’s a great book and a great look at the history of archaeology available in different stages of the 19th century.  She tells of times before World War II, when John Svoronos and Adolf Wilhelm uncovered the first inscriptions and when Pericles Redials was certain the device was a navigational instrument used to sail the ship. She tells of Theophanidis publishing a theory it might be driven by a water clock in 1934. She weaves in Jeaques Cousteau and Maria Savvatianou and Gladys Weinberg and Peter Throckmorton and Price and Wang Ling and Arthur C. Clarke and nuclear physicist Charalambos Karakolos and Judith Field and Michael Wright and Allan Bromley and Alan Crawley and Mike Edmunds and Tony Freeth and Nastulus, a tenth century astronomer in Baghdad. Reverse engineering the 37 gears took a long time. I mean, figuring up the number of teeth per gear, how they intersected, what drove them, and then trying to figure out why this prime number or what calendar cycle this other thing might have represented. Because the orbit isn’t exactly perfect and the earth is tilted and all kinds of stuff. Each person unraveled their own piece and it’s a fantastic journey through history and discovery.  So read the book and we’ll skip to what exactly the Antikypthera Device was. Some thought it an astrolabe, which had begun use around 200 BCE - and which measured the altitude of the sun or stars to help sailors navigate the seas. Not quite. Some theorized it was a clock, but not the kind we use to tell time today. More to measure aspects of the celestial bodies than minutes.  After generations of scientists studied it, most of the secrets of the device are now known. We know it was an orrery - a mechanical model of the solar system. It was an analog computer, driven by a crank, and predicted the positions of various celestial bodies and when eclipses would occur many, many decades in advance - and on a 19 year cycle that was borrowed from cultures far older than the Greeks. The device would have had some kind of indicator, like gems or glass orbs that moved around representing the movements of Jupiter, Mars, Mercury, Saturn, and Venus. It showed the movements of the sun and moon, representing the 365 days of the year as a solar calendar and the 19-year lunar cycle inherited from the Babylonians - and those were plotted relative to the zodiac, or 12 constellations. It forecast eclipses and the color of each eclipse. And phases of the moon. Oh and for good measure it also tracked when the Olympic Games were held.  About that one more thing with calculating the Olympiad - One aspect of the device that I love, and most clockwork devices in fact, is the analogy that can be made to a modern micro service architecture in software design. Think of a wheel in clockwork. Then think of each wheel being a small service or class of code. That triggers the next and so-on. The difference being any service could call any other and wouldn’t need a shaft or the teeth of only one other wheel to interact - or even differential gearing.  Reading the story of decoding the device, it almost feels like trying to decode someone else’s code across all those services.  I happen to believe that most of the stories of gods are true. Just exaggerated a bit. There probably was a person named Odin with a son named Thor or a battle of the Ten Kings in India. I don’t believe any of them were supernatural but that over time their legends grew. Those legends often start to include that which the science of a period cannot explain. The more that science explains, the less of those legends, or gods, that we need. And here’s the thing. I don’t think something like this just appears out of nowhere. It’s not the kind of thing a lone actor builds in a workshop in Rhodes. It’s the kind of device that evolves over time. One great crafter adds another idea and another philosopher influences another. There could have been a dozen or two dozen that evolved over time, the others lost to history. Maybe melted down to forge bronze weapons, hiding in a private collection, or sitting in a shipwreck or temple elsewhere, waiting to be discovered.  The Greek philosopher Thales was said to have built a golden orb. Hipparchus of Rhodes was a great astronomer. The Antikythera device was likely built between 200 and 100 BC, when he would have been alive. Was he consulted on during the creation, or involved? Between Thales and Hipparchus, we got Archimedes, Euclid, Pythagoras, Aristotle, Philo, Ctesibius, and so many others. Their books would be in the Library of Alexandria for anyone to read. You could learn of the increasingly complicated Ctesibius water clocks along with their alarms or the geometry of Euclid or the inventions of Philo. Or you could read about how Archimedes continued that work and added a chime.  We can assign the device to any of them - or its’ heritage. And we can assume that as with legends of the gods, it was an evolution of science, mathematics, and engineering. And that the science and technology wasn’t lost, as has been argued, but instead moved around as great thinkers moved around. Just as the water clock had been in use since nearly 4000 BCE in modern day India and China and become increasingly complicated over time until the Greeks called them clepsydra and anaphoric clocks. Yet replacing water with gears wasn’t considered for awhile. Just as it took Boolean algebra and flip-flop circuits to bring us into the age of binary and then digital computing.  The power of these analog computers could have allowed for simple mathematic devices, like deriving angles or fractions when building. But given that people gotta’ eat and ancient calculation devices and maps of the heavens helped guide when to plant crops, that was first in the maslovian hierarchy of technological determinism.  So until our next episode consider this: what technology is lying dormant at the bottom of the sea in your closet. Buried under silt but waiting to be dug up by intrepid divers and put into use again, in a new form. What is the next generation of technical innovation for each of the specialties you see? Maybe it helps people plant crops more effectively, this time using digital imagery to plot where to place a seed. Or maybe it’s to help people zero in on information that matters or open trouble tickets more effectively or share their discoveries or claim them or who knows - but I look forward to finding out what you come up with and hopefully some day telling the origin story of that innovation!