The Antikythera Mechanism

Does this ancient device, 1000 years ahead of its time, prove we were visited by aliens or time travelers?

by Brian Dunning

Filed under Ancient Mysteries

Skeptoid #184
December 15, 2009
Podcast transcript | Listen | Subscribe
Also available in Chinese

Imagine the year 1900. The skies are leaden gray, the dark waters all around you shiver with the approach of a distant storm. You're in the warm Ionian Sea in the Mediterranean, sheltering along the coast of the barren and barely populated island of Antikythera, waiting out a storm. It's frustrating because you're on your way home from Africa where you and your crew have been diving for sponges. Your captain, Dimitrios Kondos, thinks the lost time may as well be put to good use, so he orders you below to see what sponges you may be able to find here. You don your copper diving helmet and heavy suit, and they lower you into the depths. Streaks of dull gray light from above shimmer around you as the rocky bottom approaches.

But it's not sponges you find. Minutes later you're back on board the ship, jabbering excitedly, so incoherent that Kondos thinks you have carbon dioxide poisoning. He goes down himself to have a look. And what Kondos and his crew bring up over the subsequent two years comprises one of archaeology's great finds, that truly challenged our understanding of the history of technology.

Chief among the finds was what has become known as the Antikythera Mechanism, fragile chunks of green corroded bronze, that when picked apart, revealed unexpected mechanical components, mainly gears. The device was surprisingly complex. At first it was thought to be a clock, but when Greek inscriptions were found, it turned out to be a sort of astrolabe for predicting eclipses and moon phases and the positions of the planets, of unprecedented sophistication. So sophisticated, in fact, that everything we knew told us that the Antikythera Mechanism was a full 1,000 years out of place.

The shipwreck, known as the Antikythera Wreck, has been dated to the first century BCE. The Antikythera Mechanism dates from the century before that. And then, so the popular version of the story goes, nobody on Earth had either the astronomical knowledge, nor the mechanical know-how, to construct such a device until a millennium later. Some have said the Antikythera Mechanism is therefore proof of time travel, alien visitation, or Atlantis.

Physically, the device was about the size of a shoebox, with wooden sides and bronze faces. On the front face were two large and three small output dials. On the back were three concentric output dials. To operate the device, you turned a crank on the side which rotated at least 30 gears inside the machine, some of which were epicyclic. The hands that went round each of the two large dials swept over spiral slots, with a pin on the arm that rode in the slot, similar to a needle following the groove on a record. By setting some preferences, such as what type of calendar you wanted to use, and turning the side crank to select the current date, you could learn all sorts of things: Whether this was an Olympics year, when the next solar and lunar eclipses were (by date and hour), where the twelve constellations were along the ecliptic, the phase of the moon, and the positions of the five planets known at the time.

Although we now know what the device did, we're not sure what its use was. By its construction in bronze, which readily corrodes, we know it was not designed for navigation at sea. Astronomers and astrologers probably could not have afforded it. It could have been used as an education tool. Most likely it was built for wealthy Romans who had some interest in its features, probably not too different from early adopters who wanted to have the first iPhone with all the cool apps. The wreck was laden with other objects of great value, most notably a vast hoard of coins and a Peloponnesian bronze sculpture, a larger-than-life young man called the Ephebe.

So what about these claims that the mechanism is 1,000 years out of place, and no humans had the knowledge to make something like it? Does this prove that aliens, Atlanteans, or time travelers must have been involved? It is a fact that the Antikythera Mechanism is substantially more complicated than any other mechanical devices known from its time. Specifically, it's one of the earliest known uses of meshing gears. But contrary to the popular telling, it's not the oldest. Gears were used to drive doors and lift water in India as early as 2600 BCE, two and a half millennia before the Antikythera Mechanism. Aristotle described the function of gears in the 4th century BCE. 100 years later, Dionysius of Alexandria used gears in his automatic arrow firing machine gun. The Greek National Museum contains examples of epicyclic gears from the period. Archimedes was making all sorts of mathematical and mechanical inventions at the time. For hundreds of years, Greek astronomers had been studying the movements of heavenly bodies, and by Archimedes' lifetime, all the motions replicated on the Antikythera Mechanism were known to science.

We know a lot about where and when the device was made from the inscriptions in the bronze. The back face is covered with instructions for its use, as is its inside if you open the device. These include descriptions of the controls, various calendars, and mentions of the celestial bodies tracked by the device. By the language and terminology used, as well as by the context of its find among the other artifacts recovered from the Antikythera Wreck, we now have a pretty good idea of where and when it was built: The middle of the 2nd century BCE, probably in Syracuse or Corinth.

What we don't know is who built it, but there are some good candidates. It is assumed that Archimedes, who died several decades before the device was built, left behind a tradition of scientists who continued his work and built upon his inventions, and the device could have come from this school. Another leading contender is Hipparchos, perhaps the greatest of early astronomers, who was in his heyday when the Antikythera Mechanism was constructed. Most notably, Hipparchos was the first to devise a mathematical model to predict the anomalies of the moon's movement, and the Antikythera Mechanism contains a gear set to reproduce exactly these computations.

Most archaeologists agree that this particular device was neither unique nor the first of its kind. Two factors contribute to this: First, its design is quite refined, which is not consistent with a prototype. Second, an object as expensive and complex as this would typically be made in a series in order to recover the costs of design. Why, then, are its siblings not found? Probably because they were made of bronze, and bronze was highly recyclable and valuable. Few commonplace bronze objects from the ancient world survive for this reason, except for those that were lost at sea and thus escaped recycling. If there were other computational devices made in the period, it is not suprising to archaeologists that they were lost to history and are unknown.

The surviving fragments of the device at the Greek National Archaeological Museum are too fragile to travel, and so in 2005, two teams brought their equipment to Athens to perform the most advanced imaging studies to date. Hewlett Packard's team performed polynomial texture mapping to high resolution images of the inscriptions, made with lighting from all different angles to reveal every possible bit of detail. A company called X-Tek Systems brought their 8-ton x-ray machine called the BladeRunner to the museum, all the way from the UK, and made CT scans. CT, or computed tomography, is the process of creating a 3-D image from slices; in this case, slices from x-ray images. We now have extremely detailed maps of the internal mechanism and transcripts of all the surviving inscriptions.

And, as a result, we now know that the ancient Greeks were building far more advanced computational devices than we used to give them credit for. We knew they had the knowledge, we just didn't know they were translating it into bronze so exquisitely.

Tip Skeptoid $2/mo $5/mo $10/mo One time

Antiscience people love to point to cases like the Antikythera Mechanism as examples of science being wrong. They gloat over their belief that historians have been embarrassed, careers shattered, books proven to be in error. They imagine that researchers at universities everywhere are being fired or stripped of their credentials. They believe this case adds to an ever-growing mountain of proof that science is, itself, destined to inevitable failure, and that enlightened scientists should abandon their practice and turn to faith in the supernatural.

In fact, nothing could be further from the truth. A find like this, that substantially revises our understanding of history, can be the crowning achievement for a scientist's career. Contrary to what antiscience would have you believe, scientists do not fear new discoveries, they long for them. Every action dictated by the scientific method seeks to learn something new, to revise and improve our understanding of nature or history. Major finds represent major improvements to our theories. Thanks to the Antikythera Mechanism, we now have a better understanding of technology in the ancient world, and new directions for researchers to turn. The idea that a discovery like this is embarrassing, or exposes weakness in the scientific method, is absurdly upside-down and backwards.

Many times I've heard the argument made that scientists fear new discoveries because it would threaten their grant money, so it's in scientists' best interests to cover up anything new. All you have to do is look at what's being funded these days to see how wrong this particular conspiracy theory is. A glance at the National Science Foundation's list of recent funding awards teaches one lesson: If you want grant money, be a maverick, have something new and exciting. What's a financial incentive for scientists to look for discoveries that challenge our worldview? New discoveries attract grant money, and grant money leads to more new discoveries. There is no money in continuing to grind over what we already know. So please, can we put this particular conspiracy theory to bed?

It's not every year that we find something so historically significant, and that we learn so much from. The rewards we gain from increasing our knowledge by studying them are inestimable. Those who dismiss such finds as alien, or otherwise not part of history, miss out on that knowledge. The lesson to learn is that when you're confronted by a discovery, stopping at the popular supernatural explanation is guaranteed to lead you nowhere. Instead, you should do what science suggests, and be skeptical.

Brian Dunning

© 2009 Skeptoid Media Copyright information

References & Further Reading

Edmunds, M. "Project Overview." The Antikythera Mechanism Research Project. School of Physics and Astronomy, Cardiff University, 1 Jan. 2007. Web. 26 Jan. 2010. <>

Fine, J. Lost on the Ocean Floor: Diving the World's Ghost Ships. Anapolis: Naval Institute Press, 2005. 83-85.

Freeth, T. "Decoding an Ancient Computer." Scientific American. 1 Dec. 2009, Volume 301, Number 6: 70-83.

Hardersen, P. "Mickey Mouse Discovers the 'Real' Atlantis." Skeptical Inquirer. 1 Jan. 2002, Volume 26, Number 1: 42-43.

Kanas, N. Star Maps: History, Artistry, and Cartography. Chichester: Praxis Publishing Ltd., 2007. 240-241.

Price, D. "An Ancient Greek Computer." Scientific American. 1 Jun. 1979, Volume 200, Number 6: 60-67.

Reference this article:
Dunning, B. "The Antikythera Mechanism." Skeptoid Podcast. Skeptoid Media, 15 Dec 2009. Web. 8 Oct 2015. <>


10 most recent comments | Show all 55 comments

If technology was so capable at that time, where did it go and what explains the absence? Do we evolve to a point where our technology outruns our general intelligence. We have these wonderful computers right now, but what if the grid collapsed? Surely then we would see that to find food and water would be a better skill set than developing a spreadsheet.

Zach Davis, Maricopa, Arizona
October 22, 2012 3:16pm

Technology has outrun general intelligence a long long time ago. Thats why the majority of people have always been "users".

By the last bit Zach, I certainly think you should be practicing finding food and water.

Mud, missing point, NSW, Oz
January 23, 2013 12:14am

I don't think it was aliens.and I don't think that the ancient people know more for there time.I think we now don't have the knowledge we need to have for this time. Sorry for my bad english.

dusan, ruma
June 17, 2013 10:00am

I've always been fascinated by the utter vacuity of pretend 'researchers' who immediately postulate an alien/super-advanced origin for ancient works of engineering or technology. Take the Antikythera Mechanism: it is made of bronze, uses fairly primitive gearing and shows certain astronomic features that were already long-known before its date of production - what it does is combine them in an easier, more compact form, that's all; when divers come up with an ancient mechanism made in plastics and platinum, that functions with electricity, microprocessors and transistorised circuits, and that can give information (quantum equations, string theory etc) that cannot be deduced from observation of the common or garden world, then I'll start thinking seriously about these mythical super-advanced Atlanteans or Alien visitors at the dawn of civilization (and even then, only if a genuinely ancient provenance for the object can be definitively proven). There are too many half-educated people 'agape for wonders' who have not the application to study real history and appreciate the REAL wonders that ancient human abilities were capable of.

Rob Horne, Colombo, SL
June 23, 2013 6:24am

"If technology was so capable at that time, where did it go and what explains the absence."

Social upheaval, the collapse of civilization, and then reprocessing the components into raw materials.

Another Nick, Alexandria VA
July 10, 2013 11:53am

For me the really marvellous thing about the Antikythera Mechanism is the hypothetical "what if" games it allows us to play with history - what if, instead of regarding such technology as a clever gadget of peripheral significance (as seems to have been the case?) the Ancient Greeks or Romans had taken the idea of a "calculating engine" and run with it? In such a (hypothetical) alternative history, could the computer age have come to pass centuries earlier than it did? What changes would this have wrought to history as we know it? It's an intriguing flight of fancy... Well done Brian on another very elegant presentation. As a practicing scientist and educator, I thought that your lyrical defence here of the scientific drive to discover new things was an powerful point, beautifully made.

Hemlock, Australia
July 21, 2013 6:23am

Hemlock, Just another example of the effect of fifty years of Roman Civil war did to cruel the empirical sciences that were well established prior to the end of the second century.

Many things the west had to rediscover that would have been great technological bases for development.

But, the antikythera device indicates that science had a true disdain for astrology even in the ancient and antiquarian greco roman world.

Mark one up for 2.5 millenia of deserved derision!

Maughter Diller's, Greenacres by the sea Oz
August 26, 2013 7:54am

Read Dava Sobel's "Longitude". The Greeks likely hit upon the idea of using the moon and planets to get a sense of time and hence a rough estimate of longitude. Certainly a little better than guessing.

Ned Dubois, Jericho, VT
September 10, 2013 12:53pm

Thanks for at least giving us another reason that greeks had already had a great understanding of the earth being some sort of sphere.

Must rot the sox of genesis baiting creationists.

Genesis baiting? Debate one and you too will find that you can quickly dispel their posits to a series of question begging by allusion on one verse only.

Done to death elsewhere in skeptoid.

Moister Door, Greenacres by the sea Oz
September 17, 2013 4:39pm

"For me the really marvellous thing about the Antikythera Mechanism is the hypothetical "what if" games it allows us to play with history - what if ... the Ancient Greeks or Romans had taken the idea of a "calculating engine" and run with it? In such a (hypothetical) alternative history, could the computer age have come to pass centuries earlier than it did?"

I don't think it would. My wife and I have explored the implications in our novel series "Romanike" where a copy of the Antikythera Mechanism initiates a major power struggle in the Roman Empire: The simple fact that it is the only one of its kind has the psychological effect of a nuclear bomb in the hands of a terrorist. But mechanical gears have never been a mystery to Greek or Roman engineers: they applied them in mills, in military engines, in water clocks etc. The only surprising aspect about the Antikythera Mechanism is the subtlety with which its gears have been wrought. The development of calculating engines was hampered by a major drawback, however: The clumsiness of their number systems and the lack of the number 0. Hence, the Antikythera Mechanism does not really "compute", it just moves pointers.

Codex Regius, Wiesbaden
November 11, 2014 9:54am

Make a comment about this episode of Skeptoid (please try to keep it brief & to the point).

Post a reply


What's the most important thing about Skeptoid?

Support Skeptoid

About That 1970s Global Cooling...
Skeptoid #487, Oct 6 2015
Read | Listen (12:13)
The Flying Saucer Menace
Skeptoid #486, Sep 29 2015
Read | Listen (12:29)
Holocaust Denial
Skeptoid #485, Sep 22 2015
Read | Listen (12:54)
More Unsung Women of Science
Skeptoid #484, Sep 15 2015
Read | Listen (12:56)
Unsung Women of Science
Skeptoid #483, Sep 8 2015
Read | Listen (13:13)
#1 -
Tube Amplifiers
Read | Listen
#2 -
Read | Listen
#3 -
That Elusive Fibromyalgia
Read | Listen
#4 -
SS Iron Mountain
Read | Listen
#5 -
A Skeptical Look at the News
Read | Listen
#6 -
The War of the Worlds Panic Broadcast
Read | Listen
#7 -
Ancient Astronauts
Read | Listen
#8 -
Myths of Alcatraz
Read | Listen

Recent Comments...

[Valid RSS]

  Skeptoid PodcastSkeptoid on Facebook   Skeptoid on Twitter   Brian Dunning on Google+   Skeptoid on Stitcher   Skeptoid RSS

Members Portal


Follow @skeptoid

Tweets about skeptoid

Support Skeptoid

Email: [Why do we need this?]To reduce spam, we email new faces a confirmation link you must click before your comment will appear.
characters left. Abusive posts and spam will be deleted.