The Antikythera Mechanism: Art or Science?

The Antikythera Mechanism. Photo (cc) Tilemahos Efthimiadis.

The Antikythera Mechanism. Photo (cc) Tilemahos Efthimiadis.

This post was chosen as an Editor's Selection for ResearchBlogging.orgSome posts take quite a while to write. This is a response to Candy Minx and Martin Rundkvist who were dis­cuss­ing the Antikythera Mechanism back in 2006 (Antikythera, Time, A Reply to the Minx). Candy Minx thought that the Antikythera Mechanism was an expres­sion of what was already known and embed­ded in a soci­ety through things like myth and ritual. Martin thought that the mech­an­ism was far more com­plex, indeed need­lessly com­plex, for an ancient soci­ety and so was some­thing quite dif­fer­ent to the folk astro­nomy of the time. Originally I planned to write a fence-sitting com­prom­ise. I thought that Candy Minx was right to an extent, there was no need for a device like this because rituals and folk obser­va­tion could allow people to time the year as well as they needed. At the same time I thought that Martin was right to point out that the mech­an­ism gave res­ults with far more accur­acy than folk astro­nomy needed, or would even recog­nise. A dif­fer­ent sort of astro­nomy is vis­ible in the Antikythera Mechanism. I didn’t blog too much about the 2006 paper because I atten­ded a few of Mike Edmunds’ talks on the topic and heard that more would be pub­lished, which happened in 2008. Anyhow in my own fluffy and fence-sitting way I’ll now offer my compromise.

Someone with an extraordin­ary ima­gin­a­tion built the Antikythera Mechanism and, if he were alive today, we wouldn’t hes­it­ate to call him a sci­ent­ist. I don’t know if the designer was in the same league as Newton or Galileo, but he was cer­tainly the equal of Kepler, Copernicus or Brahe. It’s hard to over­state how extraordin­ary the device described in the 2006 paper is, but I’m going to give it a go.

If you’re the one per­son who hasn’t heard of the Antikythera Mechanism then Nature have a handy video introduction.

All that remains now is a col­lec­tion of cor­roded lumps found off the island of Antikythera. The 2006 paper described what the team dis­covered after x-raying the lumps to read the hid­den inscrip­tions without priz­ing apart the device and dam­aging it. Prior to this paper it was thought that the device could keep track of the Sun and the Moon. This is no small feat.

Epicycle et deferent. Image by Dhenry @ Wikimedia Commons.
Epicycle et defer­ent. Image by

The Sun would be mov­ing slowly against the back­ground stars, so over the course of a year it would pass through all the signs of the zodiac. The Moon how­ever is more com­plex. The Moon also moves in front of the back­ground stars, but it only takes about 27 days to do this. It’s called the sider­eal period. So you need a couple of gears to drive those two motions. But you wouldn’t really think of the sider­eal period as a month. For most people the syn­odic period, the time between one New Moon and the next or the time between one Full Moon and the next, is a month. This is around 29½ days. Throw in extra gears for driv­ing other dis­plays show­ing eclipse cycles and it’s clearly a com­plex device. The ori­ginal stud­ies found evid­ence of epi­cycles, gears moun­ted on other gears. Add other fea­tures like dis­plays for eclipse and lunar cycles on the back and it’s obvi­ous you have a com­plic­ated device. The 2006 research showed that in fact it was all a bit more com­plic­ated than that.

The Moon’s move­ment isn’t con­stant. It speeds up and slows down. This is because its orbit isn’t exactly cir­cu­lar. Instead it’s slightly egg-shaped. The point fur­thest from the earth is the apo­gee and the point closest to the Earth is the peri­gee. When it’s near the apo­gee it travels slowly, but when it moves closer to the Earth it picks up speed until it passes peri­gee and then it slows down again. This is called the first lunar anom­aly. The dif­fer­ence is notice­able by the naked eye, if you’re will­ing to make sys­tem­atic obser­va­tions. This is all simply explained by Kepler’s Laws of Planetary Motion. There’s small prob­lem. Kepler used ellipses.

You can’t use ellipt­ical gears. The point of gears is that they must have inter­mesh­ing teeth. An ellipt­ical gear would lose con­tact with the driv­ing gear as its axis changed. Instead it seems that the mech­an­ism used two gears, one slightly off-axis from the other. The rota­tion was con­nec­ted by a pin-and-slot arrange­ment, so that the one gear wouldn’t turn at quite the same rate as the other gear. The on-axis gear can then be turned reli­ably by the drive gears, while the motion of the moon can driven by the off-axis gear. So you have a device that can track the sider­eal, syn­odic and anom­al­istic months, all while the Earth is spin­ning round the Sun. If that’s caus­ing your head to spin you might want to skip the next paragraph.

There’s another prob­lem. The lunar anom­aly describes the Moon’s travel from one apo­gee to the next. This apo­gee is also rotat­ing around the earth. If the apo­gee is in Aries then two and a bit years later it will be in Cancer, and another two and a bit years to move into Libra until it too has trav­elled through the zodiac over about nine years. So now we have a device which tracks the Moon around the Earth, and its phases and it’s vari­able speed and vari­ations in that vari­ab­il­ity, while also keep­ing track of the Sun’s pos­i­tion, poten­tial lunar and solar eclipses and inter­cal­a­tion cycles so you know when to stick an extra month in to keep the lunar months in step with the solar year round gears, some moun­ted slightly off axis to cre­ate a pseudo-sinusoidal vari­ation using cir­cu­lar gears to replace ellipses. If you have funny feel­ing near the back of your head right now, that’s prob­ably your brain try­ing to crawl out of your ears. The Antikythera Mechanism is insanely com­plex. Still just because it’s insanely com­plex, that doesn’t make it sci­entific.

In fact you can argue about whether or not Science exis­ted in the ancient world. Certainly a lot of ele­ments like test­ing ideas with exper­i­ments didn’t really become pop­u­lar till after Galileo. On the other hand some nat­ural philo­sophy of the time was based on obser­va­tion. There was cer­tainly tech­no­logy which was the res­ult of applied know­ledge. With those kind of pro­visos a lot of ancient his­tor­i­ans would be happy with the idea of ancient sci­ence, albeit a sci­ence dif­fer­ent to post-Renaissance sci­ence. In this case, the sheer intense obser­va­tion and cal­cu­la­tion involved in mak­ing the Antikythera Mechanism marks it out as a work of ancient sci­ence. There’s also another factor which might make it more sci­entific than artistic.

To some extent the Antikythera Mechanism Research Project have been inter­ested in hanging a name on the device. It was thought to have ori­gin­ated in Rhodes and sunk on its way to Rome, which would have con­nec­ted it to the home city of Hipparchus, one of the great astro­nomers of antiquity. The 2008 paper has examined the parapegma on the mech­an­ism and dis­covered it may be con­nec­ted to Syracuse, home of Archimedes.

A parapegma is a cal­en­dar, usu­ally with holes for stick­ing a peg into for mark­ing the days. In the case of ancient Greece they’re inter­est­ing when they tell you what day of the month it is, because each Greek city had its own set of months. The months were usu­ally named after reli­gious fest­ivals, and this was tied into local polit­ics. That meant hav­ing your own cal­en­dar was a good way of show­ing your inde­pend­ence. The best match for the months men­tioned on the mech­an­ism is Tauromenion, mod­ern Taormina, in Sicily. This is likely to have shared some months with Syracuse as it was re-settled from there in the fourth-century BC, so Syracuse is a strong pos­sib­il­ity for the home of this device. Archimedes is said to have inven­ted a plan­et­arium accord­ing to Cicero and is thought to have writ­ten a lost book on astro­nom­ical devices. However he could not have made this device. Archimedes died in 212 BC. The Antikythera Mechanism is cur­rently thought to date to the second half of the second cen­tury BC, but that might change. But it was very likely to have been made after Archimedes death and that’s what makes it scientific.

Art can be col­lab­or­at­ive, or it can be per­sonal. Science in con­trast is built on cumu­lat­ive know­ledge. The per­son who inven­ted the gear­ing did not have to be the per­son who made the astro­nom­ical obser­va­tions. He didn’t even need to live in the same cen­tury as the astro­nomer. In fact the maker of this device might not have done either. He could have fol­lowed a kit and added his own per­sonal touches on the cas­ing. There’s a core to this device which, once expressed, is inde­pend­ent of per­sonal vis­ion. Archimedes didn’t have his own per­sonal Moon which moved in a dif­fer­ent way to every­one else’s, while an artist can have a per­sonal inter­pret­a­tion of the Moon.

A reason people might think the Antikythera Mechanism is a work of art is that it’s clearly the res­ult of a lot of ima­gin­a­tion. Great art requires ima­gin­a­tion, but so too does great sci­ence. It requires the kind of ima­gin­a­tion that can look at a tool­box full of circles and see ellipses. The kind of ima­gin­a­tion that can watch wheels turn within wheels as bod­ies waltz to the music of the celes­tial spheres. Another com­mon factor between art and sci­ence is that great art can show a new way of look­ing at the world, and great sci­ence does this too. That’s why I dis­agree with Candy Minx when she says “Science is always play­ing catch up with the poets.” Science can reveal beauty too, as a visit to the Antikythera Mechanism Research Group’s homepage would show.

Freeth, T., Bitsakis, Y., Moussas, X., Seiradakis, J., Tselikas, A., Mangou, H., Zafeiropoulou, M., Hadland, R., Bate, D., Ramsey, A., Allen, M., Crawley, A., Hockley, P., Malzbender, T., Gelb, D., Ambrisco, W., & Edmunds, M. (2006). Decoding the ancient Greek astro­nom­ical cal­cu­lator known as the Antikythera Mechanism Nature, 444 (7119), 587–591 DOI: 10.1038/nature05357

Freeth, T., Jones, A., Steele, J., & Bitsakis, Y. (2008). Calendars with Olympiad dis­play and eclipse pre­dic­tion on the Antikythera Mechanism Nature, 454 (7204), 614–617 DOI: 10.1038/nature07130


When he's not tired, fixing his car or caught in train delays, Alun Salt works part-time for the Annals of Botany weblog. His PhD was in ancient science at the University of Leicester, but he doesn't know Richard III.

12 Responses

  1. alun says:

    Aaargh! One of the things that finally gave me the kick to fin­ish writ­ing this was find­ing Gary Corby’s post on the Classical Athenian Calendar, which for­got to link to.

  2. Candy Minx says:

    Hello! Long time no see. I’ve missed you! I really really enjoyed read­ing this art­icle. I can’t see the date you pos­ted this so maybe it was years ago and you’ll never see this com­ment. I’m going to go and read Gary Corby’s post and I’ll be back.

    (off the top of my head though…science being beau­ti­ful is not the same as, nor does it dis­miss, poetry being able to artic­u­late and trans­mit inform­a­tion sooner or in a more effect­ive way than sci­ence. Plus, I have no argu­ment with you that “sci­ence can reveal beauty”. My argu­ment was that poetry and art have been able to artic­u­late con­cepts that sci­ence is still not able to “prove” or are often behind due to it’s lim­it­a­tions. But…let me read Corby’s post and return later. And Alun, you are so kind to even give any of my thoughts con­sid­er­a­tion, I am honored and pleased by you link­ing my blog and… gasp…quoting me. Later!)

  3. alun says:

    I thought I’d com­ment on it, because while I dis­agree with the line Science is always play­ing catch-up with the poets, I think you’re extremely right about the import­ance of social activ­ity in earlier astro­nomy. Hopefully I’ll be fin­ish­ing up a paper soon which shows how right you are and I’ll send you a copy.

    I’ve also boos­ted the col­our on the date sec­tion below the tags to make it more visible.

  4. GaryCorby says:

    Hi Alun, thanks for the link, I didn’t even know you had this site. It’s a thing of beauty!

    One thing that puzzles me about Antikythera: are we just unbe­liev­ably lucky to have found a device of which there may have been only one or two in the entire world? Or did someone man­u­fac­ture enough of these that, stat­ist­ic­ally, it’s reas­on­able for one to have been discovered?

    • joe says:

      Hello, I would think only one of these were made.
      Perhaps man could deep dive for more but it’s a needle in a hay­stack of course. why one made ?
      I believe it would have been inten­ded as a gift to the emperor or caeser of the time so he could posses it as it would have been expec­ted for his use only, as exclus­ive as he was him­self. then passed on to the next leader–of rome ?
      who was in that pos­i­tion back then ? In rome..

      Also: As we search whther it’s inten­tional for his­tory or acci­dental, soo strangely these types of (keys) are found to open his­tor­ies trap door as so rar­ley done.
      Have faith, as tech grows, we will find more keys to deepen man’s history..

      • Joe S says:

        I agree Joe. history’s door will open again as it has many times just over this past 50 years.
        I only see one of these made, as a gift and a sur­prise gift at that, so no one knew of it except those on board and archemedes who thought it out and built it. there is many hun­dreds if not thou­sands of new yet ancient dis­cov­er­ies yet to be made. lets search and dig, together..

  5. Candy Minx says:

    Oh thanks I can see now that this is a com­pletely new post. Wow. Guess what Alun, I also have a paper hope­fully I’ll be fin­ish­ing up soon too. I was really quite thrilled to read this post the other day. I think you’ve done a won­der­ful job and I got quite involved think­ing about many aspects of this dis­cus­sion from a few years ago…the pleas­ure I have read­ing your posts got me think­ing and recall­ing this past dis­cus­sion and life /he uni­verse etc. :) I had actu­ally thought you weren’t blog­ging any­more so I was so pleased to see you’ve been busy writ­ing away here after all. I would have been around more often if I had known.

    I real­ize my flip­pant remark…is well…flippant. When I said “sci­ence is always play­ing catch-up with the poets”…it’s not exactly the whole story. And it’s not as if there is some kind of com­pet­i­tion between the fields of prac­tice with poetry/literature and sci­ence, which I also implied…rather con­fus­ingly har! I wanted to sug­gest a line of thought to Martin but not quite so closely or poten­tially able to sound incen­di­ary. Rather I was aim­ing to sound dar­ing! And as I said I have been work­ing on a paper on the social activ­ity of pre­l­it­er­ate soci­et­ies and non-European (non “Enlightenment”) sci­ence activ­it­ies myself. I hope that I can fin­ish up with an object and argu­ment half as good as your writ­ing here on this sub­ject. You are truly inspir­ing. I am also touched to hope…that not only did your blog influ­ence or inspire me…but it seems per­haps in my own flounder­ing man­ner maybe I gave you a little inspir­a­tion too.

    Although I have a very spe­cific argu­ment in my paper I can’t share that with you on the blogs until I have it completed…I’m sure you understand…but maybe I can artic­u­late my pre­vi­ous flip­pant line. :) More accur­ately I should have said that poetry has always been able to artic­u­late con­cepts that sci­ence has yet to be able to artic­u­late as suc­cess­fully. Poetry explores and puts words to con­cepts that are often intan­gible more suc­cess­fully than sci­ence, so far, has been able to do.

    I have learned a les­son since post­ing that line on Martin’s blog that some­times a little light­hearted line hint­ing at more mean­ing is a poten­tially shabby way to com­mu­nic­ate a ser­i­ous topic or intu­ition or know­ledge. I also want you to know that the irony of the situ­ation has not escaped me. In order to present an argu­ment defend­ing my pos­i­tion I shall have to use sci­entific obser­va­tions and account­ab­il­ity. You inspire me on that front too Alun.

    And so in order to clear up and focus on my intent rather than my poor word choices, per­haps too cas­ual, let me repeat …

    Poetry has always been able to artic­u­late intan­gible con­cepts that sci­ence has yet to be able to artic­u­late as suc­cess­fully. Poetry has come closer to answer­ing some of life’s nat­ural and philo­soph­ical quests in ways that sci­ence has not been able to adequately address.

  6. alun says:

    After a few days thought, I still don’t have a clear answer. I think there could have been a few of these. Once you’ve made one you can make many, but sur­vival rates would have been very poor. It’s intric­ate and you’d need a skilled worker to fix it when it inev­it­ably went wrong. If you don’t have a worker like that then the device is just so much scrap metal and would be melted down. There’s an argu­ment that Cicero saw a sim­ilar mech­an­ism to this one, which would make two known, but it’s guess­work as to how many more there were or weren’t.

  7. joe S says:

    I bought a book about Aristarchus of Samos. ‘The ancient cop­ur­ni­cus’ by: sir Thomas Heath—and I find sim­u­lar­it­ies in the book and the atick­ythera mech. Was won­der­ing if any­one has fur­ther pur­sued a con­nec­tion of this book and the mech­an­ism ? Probable ?

    I think it could use some home­work.. Science pur­sues all avenues.

    • joe S says:

      Possibly star­ted by Aristarchus along with oth­ers such as Philolaus and archytes–Apollonios of pergo–Eratosthenes of cyrene-Archamedes and Aristotle too–Scorpinas of syra­cuse who all left marks on pos­ter­ity many mech­an­ical and gnomonic appli­ances which they inven­ted, explained on math­em­at­ical principles.

      Could the anti­kythera mech­an­ism been based, from these men who through con­jured thought, con­ceived designs from their learned, believed and applied data over a 1 or 2 cen­tury period ?

      Afterall, with all it’s com­plex­ity it’s pro­duc­tion might be the res­ult of their mul­tiple hypo­thesis and know­ledge, his­tor­ical con­sequnces and gathered col­aber­a­tions soon after for it to be even­tu­ally con­struc­ted ?
      by one (or two ?) who con­nec­ted all the dots so to speak..
      so who made it ?
      or has the limb broken from under me.…

  1. September 28, 2009

    […] The Antikythera Mechanism: Art or Science? The Antikythera Mechanism is a remark­able ancient machine which was dis­covered off the coast of the island of Antikythera in 1901; recent research has shown it to be more com­plic­ated than ori­gin­ally appre­ci­ated.  Alun at AlunSalt dis­cusses the device and spec­u­la­tions about its purpose. […]