The Antikythera mechanism is one of the most mysterious and fascinating ancient inventions from the ancient world. Largely a mystery until the last few decades, the device has fascinated scientists and the public for more than 120 years.
But, what was it? Who built it? And what did it do?
Let’s find out what we currently know about this strange ancient machine.
What is the Antikythera mechanism?
The Antikythera mechanism is an ancient Greek, hand-powered orrery (a clockwork model of the solar system) that was used to predict celestial locations and eclipses decades in advance. It is widely considered to be the oldest example of an analog computer ever found in the world and is a very enigmatic artifact.
The device was discovered in 1901 on the wreckage of a shipwreck off the shore of the Greek island of Antikythera – hence the name. However, its true significance was only identified in 1902 when the archaeologist Valerios Stais discovered that the device appeared to contain gears and surmised that it must be some kind of mechanical machine.
The gadget was originally discovered as a single lump contained in the remains of a wooden box roughly 13.4 inches (34 cm) by 7.1 inches (18 cm) by 3.5 inches (9 cm) in dimension. During later conservation work, the larger lump was separated into three primary components which, in total, appear to contain roughly 82 individual fragments. These are thought to represent around a third of the complete original machine.
Four of these fragments contain the remains of a number of corroded bronze gearwheels, while inscriptions are found on many others. The largest gear has 223 teeth and measures about 5.1 inches (13 centimeters) in diameter.
Using contemporary computer x-ray tomography and high-resolution surface scanning, a team at Cardiff University led by Mike Edmunds and Tony Freeth was able to image inside fragments of the crust-encased mechanism in 2008 and decipher the faintest writing that had once been inscribed on the machine’s outer casing.
This work showed that it contained 30 bronze meshing gears that allowed it to mimic the Moon’s erratic orbit, where the Moon’s velocity is higher in its perigee than in its apogee, as well as follow the motions of the Moon and Sun across the zodiac, and anticipate eclipses. Features on the Main Drive Wheel indicate that the device also calculated planetary motions using a complex system of gears mounted on other gears.
The instrument has been variously dated to between 150 and 100 BC or 205 BC and is thought to have been created by Greek scientists, though no one is entirely sure. Astronomer Hipparchus of Rhodes (c.190 BC – c.120 BC) is well known for his study of this motion in the second century BC, and it is possible that the device was constructed by a student of the Hipparchos school.
The historian Cicero also wrote of similar devices having been made by Archimedes in the third century BC.
In any event, it had to have been built prior to the shipwreck, which has been dated to around 70–60 BC by numerous lines of evidence. Researchers suggested in 2022 that the machine’s initial calibration date, rather than the actual date of manufacture, would have been December 23, 178 BC.
Some scholars believe that the calibration date should be 204 BC, but, again, this is hotly debated. In any case, the machine is very old indeed.
What is remarkable, apart from its age and relative level of preservation, is that nothing like it would be seen until the astronomical clocks of Richard of Wallingford and Giovanni de’ Dondi in the fourteenth century! If experts are correct about the function of the device, this would make it thousands of years ahead of its time.
Quite remarkable.
The National Archaeological Museum in Athens currently has all of the Antikythera mechanism‘s fragments as well as several artistic reconstructions and replicas that show how it would have appeared and functioned.
Alternatively, since most calendar cycles are not synchronized with the year, the cycles indicated by the various calendar cycle indicators on the back can be found in the Babylonian “ephemeris tables” for the day of the year that is currently in use.
If the mechanism were in good operating order, the crank would easily be able to hit a certain day on the dial because it moves the date marker around 78 days each full rotation. The mechanism’s interlocked gears would all revolve as the hand crank was turned, allowing for the simultaneous determination of the Sun’s and Moon’s positions, the moon’s phase, the timing of an eclipse, the calendar cycle, and maybe even the positions of planets.
The face contained a large dial with pointers for showing the position of the Sun and the Moon and a half-silvered ball for displaying lunar phases.
The position of the spiral dial pointers on the two huge dials on the back had to be observed by the operator as well. As the dials included four and five complete rotations of the pointers, the pointer had a “follower” that followed the spiral incisions in the metal. A pointer’s follower had to be manually shifted to the opposite end of the spiral whenever it reached the terminal month place at either end of the spiral before continuing.
The upper dial showed the synodic months (the time required for a body within the solar system to return to approximately the same position relative to the Sun as seen by an observer on Earth) in the Metonic cycle (a period of 19 years with 235 synodic months). This cycle was used in regulating calendars. A smaller, four-year dial, indicated the timing for different Panhellenic games, including the ancient Olympics. The lower dial has symbols to show months in which there was a likelihood of a solar or lunar eclipse.
Seems convincing.
What are some amazing facts about the Antikythera mechanism?
We’ve covered quite a bit about the device, its history, and ideas on how it worked, but if you want to know more about it, then here is a selection of interesting facts about it.
1. Yes, it is a computer….sort of
Let’s get the most obvious fact out of the way. The Antikythera mechanism can be thought of as an analog computer. At first glance, you might not think this historical artifact is anything special. Nevertheless, on further inspection, you can see sophisticated rusted gears that were certainly functional at some point.
What was its purpose? One theory is that that ancient device was used as a type of timepiece, based on a geocentric view of the universe. However, instead of hours and minutes, it displayed celestial time and had separate hands for the Sun, the Moon, and each of the five planets visible to the naked eye (Mercury, Venus, Mars, Jupiter, and Saturn).
A rotating ball showed the phase of the Moon and dials on the back acted as a calendar and showed the timing of lunar and solar eclipses. Inscriptions explained which stars rose and set on any particular date.
All of this was on a device that was about the size of a mantel clock.
2. The Antikythera mechanism was found in a Roman-era shipwreck
How was the Antikythera mechanism found? It was discovered on a sunken Roman-era shipwreck near Antikythera island, situated between mainland Greece and Crete.
The name Antikythera means “opposite of Kythera.”
The divers who found it were out looking for sponges. The ancient shipwreck provided researchers with the fragments of the “computer”, along with a treasure trove of well-preserved ancient artifacts.
3. Several of the original discovers paid for the discovery with their lives
Greek sponge divers initially discovered the wreckage in 1900 while wearing diving gear typical of the early 20th century at the time—canvas suits and copper helmets. The shipwreck was over 150 feet (45 meters) below the surface.
When the first diver came to the surface with accounts of artifacts, horses, and bodies, the captain believed the first diver had “raptures of the deep,” or rather, nitrogen narcosis brought on by the nitrogen in the breathing mix piped into the diving helmet, and which can cause hallucinations.
However, subsequent investigation in the summer of 1901 resulted in the death of one diver and the paralysis of two more due to decompression sickness, sometimes known as “the bends”.
4. It took researchers about 75 years to decipher the mechanism of the Antikythera mechanism
Researchers initially had no idea what the device was meant for or how it worked. Much of the technology was obscured by corrosion and there was more excitement surrounding the marble, coins, and pottery from the wreck.
Beginning in around 1951, physicist and historian Derek de Solla Price began studying the device in some detail, but unfortunately, he passed away in 1983 without determining how the device worked. X-ray images taken up to that point were difficult to interpret, and most mainstream historians ignored the artifact. The Antikythera mechanism would not be appreciated for what it was until the late 1990s and early 2000s.
5. It can be thought of as the first computer
Analog computers have been around for a long time, long before digital computers like the one you are probably reading this on.
From mechanical tools like a slide rule to a device that can predict the tides, there are many different kinds of “computers”.
Since the Antikythera mechanism was made to figure out dates and make predictions about astronomical events, it can actually be considered the first analog computer yet discovered.
6. The machine fascinated Jacques Cousteau and Richard Feynman
Shortly after Price’s initial publication in 1976, the renowned underwater researcher Jacques Cousteau and his colleagues dived the Antikythera shipwreck and discovered coins from the first century BCE and a few minor bronze components of the mechanism.
Renowned physicist Richard Feynman went to the National Museum in Athens a few years later to see the device.
The device sparked Feynman’s curiosity and he later wrote that the Antikythera mechanism was “so entirely different and strange that it is nearly impossible … it is some kind of machine with gear trains, very much like the inside of a modern wind-up alarm clock.”
7. The Inventor of trigonometry may have also had a hand in creating the device
Widely considered the inventor, or father, of trigonometry, Hipparchus may have had a hand in creating the Antikythera mechanism.
The ancient astronomer lived on Rhodes and was one of the first thinkers to speculate that the Earth may revolve around the Sun.
He also created the first trigonometric tables when attempting to solve problems related to spheres.
The eclipse cycle represented on the device is Babylonian in origin and Hipparchus is known for having blended Babylonian astronomical calculations with Greek. Maybe it was Hipparchus or someone associated with his school, who worked out the math behind the device?
But, we’ll never be able to know for sure.
8. The Antikythera mechanism was used for more than just celestial prediction
The device is thought to have monitored the lunar calendar, foretold eclipses, and plotted the moon’s location and phase. But, it may have also been used to keep track of the seasons and historic events like the Olympics.
A particular dial allowed the user to visualize the seasons, which would have been beneficial for agriculture.
Since the ancient Babylonians knew how eclipses work, the person who made the Antikythera mechanism made it so that it has two dials that rotate to show both solar and lunar eclipses. But the most complicated thing the mechanism could do may have been figure out how long the moon’s cycle was at a given time, and model its elliptical orbit.
9. It even came with an instruction manual
It has been suggested that the bronze panel at the back of the mechanism acted much like an instruction manual.
Written in Koine Greek, the device may originally have included either instruction on how the device works or an explanation of what the user was seeing. However, it is believed that any user would need to have extensive prior knowledge of astronomy and astronomical devices in order to use it.
10. There could be another one under the sea
Since Cousteau looked at the underwater archaeological site in the mid-1970s, not much additional exploration had been done there.
However, in 2012, marine archaeologists from the Woods Hole Oceanographic Institute and the Hellenic Ephorate of Underwater Antiquities dove into the wreck again, using advanced scuba gear.
They found a huge collection of amphorae and other objects.
This means that either the Roman ship was a lot bigger than we thought or there is another wreck down there. For many years, excavations have been going on, and new artifacts are being found all the time.
Perhaps, just perhaps, there could be another similar device just waiting to be discovered!
11. The Antikythera mechanism was impressively accurate
The device appears to have been pretty accurate, given its age.
As we previously mentioned, the mechanism has hands or pointers for Mercury, Venus, Mars, Jupiter, and Saturn, which are all visible to the naked eye.
It also has a rotating ball that shows the phases of the moon.
The parts that made these planetary pointers work are gone, but researchers on the object say that the text on the front plate of the mechanism proves that the motion of the planets was modeled mathematically using a lot of complicated gears and that the model was very accurate – around 1 degree in 500 years to be precise.
And that is your lot for today’s ancient-tech fans.
Since its discovery at the turn of the 20th century, the enigmatic Antikythera mechanism has perplexed and awed all who’ve seen or researched it. While we may never know exactly what it looked like, or precisely how it worked, it is clear that it was an impressive feat of engineering for its day.
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