Antikythera Mechanism: The World's Oldest Computer Was an Astronomer's Best Friend

By Helen LinLast Updated May 25, 2021 5:54:07 PM ET
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Photo Courtesy: Tilemahos Efthimiadis/Wikimedia Commons

In 1900, Greek sponge divers discovered three strange pieces of corroded brass — remnants of a shipwreck that happened off the coast of the Greek island Antikythera about 2,000 years ago. A couple of years later, an archeologist, who was examining the objects recovered from that diving trip, took a particular interest in those bronze pieces.

While, on the outside, the pieces don’t seem all that compelling, it was the technology inside of the bronze objects that intrigued the archeologist. Inside, there was technology that, by all accounts, shouldn’t have existed 2,000 years ago: small, clock-like gears with tiny teeth and a protractor-esque dial divided into degrees. No known object from that time — the Roman era — has ever exemplified that level of sophistication. Not by a long shot. Fascinated, archeologists dubbed this device the "Antikythera Mechanism," and have since considered it to be the world’s first computer.

The discovery of the Antikythera Mechanism at the turn of the 20th century led to decades of confusion: What was this instrument? Who made it? How did it work? Recently, researchers finally unearthed some answers.

What Exactly Is the Antikythera Mechanism?

All that remains of the Antikythera Mechanism are rusty brass gears, which used to live inside a heavily rotted wooden case about the size of a mantel clock. But, upon closer inspection, the machine is pretty incredible. Like a clock, it has a circular face, and, inside, at least two dozen rotating gears all fit together with astounding precision. According to scientists, that kind of precision shouldn’t have been possible until at least the 16th century.

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Photo Courtesy: Louisa GouliamakiGetty Images

The archeologists who first laid eyes on this artifact knew right away that it was an object of technological significance, but weren’t sure if it was a calendar, clock, or some other tool of measurement. For a while, experts thought it might be a toy planetary model or even a device used to calculate latitude.

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But a breakthrough finally came in 1959. Princeton science historian Derek J. de Solla Price figured out that the Antikythera Mechanism could predict the positions of planets and stars based on the calendar month — or, at least, it could in its prime. The device’s primary gear represented the calendar year, and, in turn, this gear moved the smaller gears to depict the movements of the planets, sun, and moon.

In the June 1959 edition of Scientific American, Price announced that the Antikythera Mechanism was the world's first mechanical computer. He said, "The mechanism is like a great astronomical clock… or like a modern analogue computer, which uses mechanical parts to save tedious calculations."

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That is, in its most basic form, a computer takes variables input by the user and completes complicated mathematical calculations to find the answer — and that’s precisely how the Antikythera Mechanism functioned. The mathematical ratios of the gears were the "code" that allowed for the device to compute and determine how the celestial objects would appear in the sky on any given day.

Newer Technology Revealed Even More About the Antikythera Mechanism

Price's discoveries in 1959 did not stop scientists from continuing to study the Antikythera Mechanism. In the early 2000s, new technology, including 3D mapping and modern X-rays, has revealed never-before-seen inscriptions on parts of the instruments. The inscribed text, written in ancient Greek, helped them figure out how the mechanism operated.

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Photo Courtesy: aluxum/Getty Images

The Antikythera Mechanism worked through one primary crank, or gear. That gear moved small orbs made of stone (or glass) across the face of the instrument. They represented the movements of Mercury, Venus, Mars, Saturn, and Jupiter. The gear also showed the positions of both the sun and moon relative to the 12 constellations of the zodiac; predicted solar and lunar eclipses; illustrated the 365-day solar calendar, as well as the lunar calendar on a 19-year cycle; and depicted the phases of the moon. The device was even capable of showing when big sporting events and festivals, like the Olympics, were to be held.

The complexity of the machine is nothing short of miraculous, especially considering its accuracy. To try to better understand it, scientists have more recently tried to recreate the Antikythera Mechanism, even using the original calculations from when the device was created. The process has caused scientists and historians to second-guess all they thought they knew about ancient Greece and the civilization’s technological capabilities. How could they have possibly manufactured such an intricate machine with the technology they had?

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Who Built the Antikythera Mechanism?

Archeologists estimate that the Antikythera Mechanism was manufactured around 100-150 BC. Thanks to references in Greco-Roman literature, specifically the writings of Marcus Tullius Cicero, historians believe that it was just one of many mechanical devices made to calculate astronomy at the time. As of now, no other surviving devices have been discovered.

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Photo Courtesy: Louis Gouliamaki/Getty Images

However, due to the ancient Greek inscriptions, and the fact that it displayed the dates of the Olympic Games, it’s pretty safe to assume that it was built in Greece. Moreover, the inscription on the ancient computing device depicts an athletic event that occurred in Rhodes, making it likely that it was manufactured on the largest of the Dodecanese islands.

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Some historians hypothesize that Archimedes built it. He was alive around the time it was constructed, and, of course, is known as an incredible engineer. Additionally, the instrument was found on a Roman shipwreck that occurred between 76 and 67 BC. That ship was probably headed toward Rome with loot soldiers had collected for Julius Caesar. It’s believed that a Roman soldier killed Archimedes, thus potentially further linking Archimedes with Antikythera Mechanism.

Other historians are not so convinced, suggesting that other Greek scientists, such as Hipparchus or Posidonius, could’ve built it. Known as an astronomer and the founder of trigonometry, Hipparchus lived on Rhodes. Even more intriguing? He was thought to be one of the first to posit that the Earth revolves around the sun. Furthermore, the device uses the Babylonian eclipse cycle’ Hipparchus is known for mixing both Greek and Babylonian scientific ideas.

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Currently, the Antikythera Mechanism is housed in Greece’s National Archaeological Museum of Athens. However, if you live in the United States and are eager to get an up-close-and-personal look at this amazing device, a replica is on view at the American Computer Museum in Bozeman, Montana.