Is ‘religion’ one of the hard historical archaeological problems?


Michael E. Smith lays down an inter­est­ing chal­lenge at Publishing Archaeology: What are the hard prob­lems in Archaeology? What ques­tions haven’t archae­olo­gists answered and aren’t likely to answer any time soon? A couple of ideas come to mind. I’ll start with the easier prob­lem to express.

Is an ancient his­tory or archae­ology of reli­gion a sens­ible project?

I’ve got an interest in ancient sci­ence, but one of the things most people research­ing ancient sci­ence would agree that sci­ence in the ancient world didn’t really exist. There’s some­thing that’s a more sys­tem­atic inquiry about nature, but some­thing like nat­ural philo­sophy would be a bet­ter descrip­tion for the clas­sical world. I’m not sure that the same term would work for other soci­et­ies because philo­sophy car­ries a lot of bag­gage too. So when aca­dem­ics talk about ancient sci­ence, there’s this under­cur­rent that we’re not talk­ing about sci­ence. Ancient sci­ence is not the same as mod­ern science.

I’ve got an interest in ancient reli­gion too. I’m not so inter­ested in the con­tent as such, more reli­gion in a socio-political con­text. That’s some­thing you can say that makes sense to mod­ern people. If you said the same thing in the ancient world they’d think you were mad. It’d be a bit like say­ing you’re inter­ested in fish, but only the ones that live in water. In the ancient world it was accep­ted that reli­gion was entwined with civic life. There’s a second prob­lem that what we call reli­gion has developed from its ancient roots.
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East is East?


Astronomical Orientation of Ancient Greek Temples

ResearchBlogging.orgI’m not plan­ning to blog a lot on the Astronomical Orientation of Ancient Greek Temples as is openly access­ible. Your com­ments are going to carry a lot more weight there than here. But I’ll try and keep track of what other people are say­ing else­where. I’m expect­ing this to be the first paper of a devel­op­ing argu­ment, so I’ll need to see what people identify as prob­lems and address them. There’s two com­ments in the Times today which I think neatly high­light one of the issues. One is from Efrosyni Boutsikas and the other from Mary Beard.

Boutsikas’ objec­tion is inter­est­ing. I wanted a com­par­ison data set to exam­ine for Greece and the only one I know of that’s pub­lished is Retallack’s in Antiquity. To be hon­est it’s not entirely fair to use Retallack’s data as he wasn’t that con­cerned with astro­nomy. Instead he was look­ing at geo­mor­pho­logy, and I think he has some really inter­est­ing res­ults. Now Boutsikas has her own sur­vey, which she did spe­cific­ally with archae­oastro­nomy in mind. That’s why I’m inter­ested when she says of 107 temples in Greece only 58% faced east. That might cause me some prob­lems and here’s why.

First we need three vari­ables. n is the num­ber of temples. That’s 107. p is the prob­ab­il­ity and event will hap­pen, and q the prob­ab­il­ity it won’t. p+q = 1 because some­thing has to either hap­pen or not hap­pen. So what value is p? It depends on what Boutsikas means by east. If she means the east­ern half of the hori­zon, then p is 0.5 and so is q. By pure chance we’d expect np temples to face east. That’s 53.5. In her sur­vey 62 temples faced east. That’s more than chance, so I’m right yes? Not so fast.

There’s never going to be exactly 53.5 temples facing east. Around 19 times out of twenty 20 there’ll be 53.5 plus or minus two stand­ard devi­ations. If you want the chance of a false pos­it­ive to be lower than 1 in a 100, then you need 53.5 plus or minus three stand­ard devi­ations. The stand­ard devi­ation (σ) for this kind of dis­tri­bu­tion is cal­cu­lated by the formula:

σ = √npq

If we want the one in twenty con­fid­ence that means

σ = √(107 × 0.5 × 0.5) = 5.2

So 19 times out of 20 you might expect to find between 43.1 and 63.9 temples facing east. The res­ult of 62 is inside this range, so there’s noth­ing sig­ni­fic­ant. How do I explain that? I’m not sure I can. I can’t say what time period her temples come from. If she’s looked at Bronze Age sites and Roman sites in Greece then we’re not com­par­ing like with like and it’s pos­sible that when we com­pare temples built in the archaic and clas­sical peri­ods as they were in Sicily then we’ll have more of a match. Another pos­sib­il­ity is that I’m simply wrong.

But this depends on Boutsikas mean­ing east­ern half of the hori­zon when she says east. I use dif­fer­ent defin­i­tions of east for dif­fer­ent tests and make clear which are which in the paper because it makes a dif­fer­ence. If Boutsikas has put her temples into four cat­egor­ies, north, east, south and west, then east means east­ern quarter of the sky and the equa­tions turn out differently.

np = 107 × 0.25 = 26.75 temples
σ = √(107 × 0.25 × 0.75) = 4.48

If east is the east­ern quarter then 19 times out of twenty at most we would expect at most 35.71 temples. By chance there’s be over 40.19 temples in the sample less than 1 time out of 100. 62 temples would be over seven stand­ard devi­ations away from the expec­ted res­ult. If that’s by chance it’s an amaz­ing freak res­ult. It means I can’t respond to Boutsikas’s claims until I can see the data to ana­lyse, so I know what east means. She might have proven my paper wrong, or else proven it very right. How can that be when only just over half of the temples face east?

Imagine you’re at a casino. Someone is spin­ning the roul­ette wheel. Half the time it lands on the num­bers 0–9 and the other half it lands on another num­ber. It doesn’t mat­ter than you can’t pre­dict exactly where the next ball will land. In the long term that casino will lose money because some­thing is affect­ing the wheel. This isn’t about hav­ing a hard and fast law for astro­nom­ical align­ments. It’s about whether or not a sig­ni­fic­ant num­ber of temples are aligned to the sun. If you’re going say that there is or isn’t a sig­ni­fic­ant num­ber, first you have to know what a sig­ni­fic­ant num­ber would look like. Typically in the social sci­ences that would np +/- 2σ. I prefer np +/- 3σ because I’m mak­ing claims which people might not be com­fort­able with, so it’s reas­on­able I should provide stronger evidence.

If I am right that doesn’t mean Boutsikas’ and Retallack’s sur­veys can be junked. In fact it means the oppos­ite. In Retallack’s case he’s show­ing there’s a clear cor­rel­a­tion between the ded­ic­a­tion of a temple and the soil type it’s built in. Now if there’s a gen­eral rule that Greek temples face east, the temples which don’t become more inter­est­ing because then you can ask “What’s spe­cial about those temples? Why were they built that way?” It’s the same for Boutsikas’ data. If there’s noth­ing spe­cial about the align­ments then temples which don’t face east are noth­ing spe­cial. If, using this method, her data shows a tend­ency for east­ern align­ments then she has a data set with plenty of inter­est­ing temples that could tell us some­thing about Greek reli­gion. For instance it could high­light where a local cult was doing some­thing spe­cial that you wouldn’t find else­where in Greece.

Clearly Boutsikas’ objec­tion is ser­i­ous and I’ll need to con­sider it care­fully, but in this case it could be a case of cross-wired. I don’t think she’d seen my art­icle when she talked to the Times because I hadn’t emailed it to her till last night. We’ve both been work­ing on sim­ilar top­ics and so could have come to the same con­clu­sions. If we been talk­ing with each other then there could have been a bit of fric­tion if we saw our ideas in each other’s theses. She’s been put on the spot react­ing to a paper which she prob­ably hasn’t read, but she’s clearly an expert in the sub­ject because of her own research. She’ll go where her research takes her and I’ll go with mine. The reporter has picked up on that con­fu­sion. Does that leave him in the dog house? Definitely not.

I’m really pleased with the way Mark Henderson has writ­ten this up. It’s not his job to preach my won­der­ful­ness, it’s to report on how this research fits in with other research. Getting the quotes from Efrosyni Boutsikas was bril­liant because it shows there’s cur­rently two mod­els which come to oppos­ite con­clu­sions. As we both pub­lish more those mod­els will get fleshed out and adapt. Which one will be accep­ted? Hers? Mine? Some kind of hybrid, or even neither? It’s not just about get­ting the right answer. At the moment we might not even agree on what the right answer will look like. Which brings me to Mary Beard’s piece.

I think it’s great com­ment­ary. I think she’s spot on when she rejects the idea of a mod­ern astro­nomy in the ancient world. I would quibble with her reject­ing astro­nomy for the rhythms of day and night. That sounds astro­nom­ical to me and there’s also evid­ence the sea­sons were import­ant. I think she might be try­ing to emphas­ise the import­ance of cos­mo­lo­gical fea­tures, in the sense of nat­ural order, rather than strict obser­va­tion. The only real puzzle is that she’s say­ing that there’s it’s obvi­ous that Greek temples align east-west when in the column next to her Efrosyni Boutsikas is say­ing they obvi­ously don’t. This is a bit of an inter­dis­cip­lin­ary gap.

From the out­side you might expect archae­olo­gists and clas­si­cists to talk to each other. They’re deal­ing with the same people in the same time period. In real­ity this doesn’t always hap­pen. A few years back the Roman Archaeology Conference, the big con­fer­ence for Roman archae­olo­gists held once every couple of years was sched­uled oppos­ite the Classical Association con­fer­ence. The two sides don’t always talk to each other. In the past few years Boutsikas has been pub­lish­ing on her work. Ioannis Liritzis and Helena Vassiliou have been arguing that Greek temples were aligned towards or away from aurorae or stars. This is hav­ing no impact amongst clas­si­cists. Equally I can’t just turn around and say “Greek temples ten­ded to face east” because all the research­ers who dis­agree could ask “How do you know?” It’s obvi­ous doesn’t work as an aca­demic response, even though I agree with Mary Beard. I don’t ima­gine that would be her response in an aca­demic forum. But what she’s done is she’s very help­fully shown that if I want to talk to clas­si­cists then show why I think I have some­thing to talk about.

That’s why I’ve had to write this paper. I want to write more, but the first ques­tion any­one can ask is “How do you know that’s not just a chance res­ult?” That’s why I developed this method. I wanted some­thing simple and effect­ive. The reason I put it in PLoS One is that it also has to be access­ible. I’m plan­ning to write more art­icles for spe­cial­ist journ­als, but people read­ing those will need access to my data and my meth­od­o­logy. That needs to be avail­able to clas­si­cists, archae­olo­gists, astro­nomers and any­one else with an interest.

You can read the ori­ginal research for free and down­load it at PLoS One. If you leave com­ments there then they’ll be seen by every­one else who exam­ines the paper. If you’d like to blog about the paper there’s a col­lec­tion of pho­tos from Sicily at Flickr with a Creative Commons licence.

Salt, A. (2009). The Astronomical Orientation of Ancient Greek Temples PLoS ONE, 4 (11) DOI: 10.1371/journal.pone.0007903

Why PLoS?


I’ve pub­lished a paper with PLoS One which should be out today. The most com­mon ques­tion I’ve been asked so far is: Why there? I’m apply­ing for jobs in Archaeology and Ancient History, so why would I want to pub­lish in an online journal that hardly any­one in those fields has heard of? Surely pub­lish­ing in one of the big journ­als would be bet­ter? Here’s a few reasons.

  1. It’s fast.
    The paper was sub­mit­ted on the 8th of September and I got the accept­ance, sub­ject to revi­sions on the 30th of September. I wouldn’t be quite so happy if it had been rejec­ted, but you have to be pre­pared for that. The faster there’s a decision the quicker you can work on the revi­sions or else re-write for another journal. The rapid response means that I can cite the data in this paper in other papers imme­di­ately rather than delay­ing writ­ing about fur­ther work.
  2. It’s access­ible.
    Research might be inter­dis­cip­lin­ary, but not so many journ­als are. For this paper the altern­at­ives would be pub­lic­a­tion in spe­cial­ist archae­oastro­nomy, clas­sics, archae­ology or astro­nomy journ­als. I can do that and will do that in the future, but writ­ing for those journ­als means writ­ing for those spe­cific audi­ences. If they’re subscription-based they also lock out a large pro­por­tion of the poten­tial audi­ence. If an astro­nomer is in a uni­ver­sity without a clas­sics depart­ment then it’s going to be hard for him to get a copy of the paper. Likewise many uni­ver­sit­ies don’t carry archae­oastro­nomy journ­als. PLoS One gives me a plat­form to intro­duce the work and then I can pub­lish tailored art­icles devel­op­ing ideas in the spe­cial­ist journals.
  3. It opens con­ver­sa­tion.
    You can com­ment on the paper. So too can any­one else. This is par­tic­u­larly handy for inter­dis­cip­lin­ary work. I’m hop­ing the con­ver­sa­tion doesn’t end with this one paper. The article-based met­rics will included some of cita­tion search. Hopefully in a couple of years people read­ing this paper will be able to see where they can find cri­ti­cisms and devel­op­ments in other papers. That’s amaz­ingly use­ful for inter­dis­cip­lin­ary work where sub­sequent papers could be in journ­als in a vari­ety of disciplines.

I’ve decided some form of open-access is essen­tial for inter­dis­cip­lin­ary work. The paper stands or falls on whether or not the bino­mial dis­tri­bu­tion is the right tool for the task. That means for aca­demic hon­esty I have to sub­mit it to a journal where the I can be reas­on­ably sure it will be scru­tin­ised by people famil­iar with basic stat­ist­ics. Scientists might laugh at that as the math­em­at­ics in the paper is very simple. I think any clas­si­cist could fol­low it, but some could quite reas­on­ably be wary of it. Is it stat­ist­ical sleight-of-hand? They can read any com­ments left by stat­ist­i­cians or astro­nomers and judge how con­fid­ent they should be in the find­ings. Likewise people unfa­mil­iar with the Greek mater­ial can read the clas­si­cists’ and archae­olo­gists’ com­ments and see if the human aspect of the research is sound.

It’s also import­ant for me because I might learn some­thing, and indeed I did. This is a bet­ter paper post-review than it was when I sub­mit­ted it. I’ve re-thought how I pro­cess some of the data and that will have a pos­it­ive on the next pro­ject I do.

After going through the pro­cess I’m impressed with PLoS. I think I hit every bump in the sub­mis­sion pro­cess, most of it due to the order­ing of the paper being dif­fer­ent to how I would nor­mally write it. Still, the every­one was very help­ful along the way. If you’re a recent PhD or grad stu­dent with a need to put out some pub­lic­a­tions, I’d recom­mend pub­lish­ing with PLoS One. Of course I’m writ­ing this before I’ve seen how the paper has been received, so you can check on my art­icle met­rics your­self to see if it’s being read or else sunk into obscurity.

Alcman and the Cosmos of Sparta by Gloria Ferrari


AlcmanI wasn’t aware of this book till I saw a review appear on the BMCR feed. If you’re tack­ling any­thing to do with ancient Greece and Rome then it’s a good idea to keep an eye on BMCR as there’s a con­stant stream of reviews high­light­ing inter­est­ing books. I’m very glad I saw this as it’s spe­cific­ally use­ful to me because of a paper I’m pol­ish­ing for sub­mis­sion. However it’s gen­er­ic­ally use­ful too because it’s a good book on the inter­ac­tion of astro­nomy, cos­mo­logy and reli­gion in archaic Greece.

The sub­ject of the book is the Parthenia (Partheneion) by Alcman (Alkman) a poet writ­ing in the 7th cen­tury BC. It describes part of a cere­mony to devote some­thing to a god­dess, pos­sibly Artemis though Bowra (1934:35) dis­agrees. He argues that ὀρθρίαι means at day-break rather than being a ref­er­ence to Artemis Orthia. This is pretty much the prob­lem with the Parthenia. It’s frag­ment­ary and even the frag­ments we do have are ambiguous.

There’s some astro­nom­ical ele­ment to the poem, but exactly what in the poem is astro­nom­ical and what is being offered is also debated. Everyone’s argu­ments about what the poem means stands or breaks on a sec­tion which Ferrari calls ‘the most tor­men­ted pas­sage in this sec­tion of the song’. Thanks to Google Books, I can add the two rel­ev­ant pages below under Pleiades, Hyades and Sirius so you can see what the prob­lem is.

The key pas­sage in near English is some­thing like:

For as we carry ὀρθρίαι φαρος
The Πεληάδες rise and struggle against us
Like the star Sirius
through the ambro­sial night.

Depending on how you trans­late the Greek words you get a dif­fer­ent outcome.

If you think φαρος is a robe or veil then you’re in good com­pany. This is known from other rituals. Usually that means that people then trans­late ὀρθρίαι to describe Artemis Orthia, a vir­gin god­dess with an interest in chil­dren and child­birth. That makes Πεληάδες the Pleiades. Many people then make this a spring fest­ival — and that for me is where this trans­la­tion breaks down.

The Pleiades are not like Sirius. They’re stag­ger­ingly unlike Sirius. Sirius is the bright­est star in the sky and the Pleiades are an open cluster of faint stars that are like a smudge of light to the naked eye. If your eyesight’s good you can make out indi­vidual stars. That would sug­gest that’s it’s not the appear­ance that mat­ters but the tim­ing of their appear­ance. In that light, the spring fest­ival makes sense. In this period the Pleiades first appeared in the morn­ing sky in May. The prob­lem is the ref­er­ence to Sirius. Sirius was set­ting in the even­ing sky at this time. It didn’t rise till July. This is why I can­not see how the poem describes a spring fest­ival. The pres­ence of Sirius seems to rule that out.

The altern­at­ive taken by a smal­ler group of people is that a φαρος is a plough. This would be Ferrari’s inter­pret­a­tion and Martin West’s too who gen­er­ally has a big brain when it comes to lyric poetry. If a plough is being brought then this becomes an autumn fest­ival. There were many har­vests through­out the year, but the agri­cul­tural year restar­ted each autumn after the last har­vest with the plough­ing of the fields. This is astro­nom­ic­ally bet­ter because Sirius would have been vis­ible in the morn­ing sky which very neatly ties to ὀρθρίαι mean­ing day-break. That’s essen­tial because Greek reli­gious ritual often happened in the morn­ing or just before sun­rise. This doesn’t give me so much of a head­ache, as it’s phys­ic­ally pos­sible, but I still struggle with the Pleiades being like Sirius. That’s why I’ve ten­ded to like a third option that Ferrari mentions.

Πεληάδες doesn’t just mean faint open cluster of stars. It also means doves. If were ser­i­ous about want­ing to solve this puzzle then I’d be look­ing at dove migra­tion and his­tor­ical and archae­olo­gical evid­ence for hunt­ing. Birds tend to migrate in autumn, that works with φαρος as a plough. Songbirds also tend to fly at night. Travelling through the sky like Sirius through the night would be a bad simile, but less so than the Pleiades as stars option to my ears. This would tie in with the kind of astro­nomy Hesiod prac­ticed. He didn’t just look at stars, but also at eco­lo­gical signs, like the migra­tions of birds and the beha­viour of other animals.

Don’t go invest­ing too much in my belief though. This is an opin­ion formed from a fairly small amount of read­ing. One of the things that makes this book so use­ful is that it draws on an extens­ive amount of evid­ence. You don’t have to agree with Ferrari’s des­tin­a­tion to see that the trip is worth­while. She also pulls in evid­ence from archae­ology and art as well as drama, espe­cially Euripides. I think it’s spec­u­lat­ive work, but it’s cer­tainly not base­less speculation.

However, I’m not fully con­vinced by the explan­a­tion. Nearly all the sup­port­ing evid­ence post-dates Alcman’s work by a long way. Euripides was writ­ing in the fifth cen­tury BC. I think that’s import­ant because I think some­thing hap­pens to astro­nomy in this period. The fifth cen­tury is when Meton pins down his luni-solar cycle. It’s also a time when there’s a stronger sense of Hellenic iden­tity, partly as a reac­tion to the threat from Persia. I think the book is extremely help­ful for explor­ing what people in the fifth cen­tury thought about the con­nec­tion between the heav­ens and reli­gion. I want to believe that we can take this evid­ence and apply it back to sev­enth cen­tury Sparta. It would make my life so much easier, but I don’t think there’s the cer­tainty in the evid­ence to fix the Parthenia to the autumn. My opin­ion might change in the future. I found the text a bit, ha ha, lac­onic. It means I’ll have to read it a few times to get a bet­ter idea of some of the more subtle argu­ments. It’s not a badly writ­ten book and def­in­itely not delib­er­ately obtuse, but it is concise.

All in all though it’s very thought-provoking. It puts some flesh on to mod­els that try and con­nect reli­gion and astro­nomy. It means that ritual isn’t just about the mater­ial, but also about how it’s used. It would be inter­est­ing to see if any­one else had evid­ence approach­ing the same prob­lem from the oppos­ite dir­ec­tion. A sur­vey of temples to see if there’s some sort of archae­olo­gical cor­rel­ate with the astro­nom­ical beha­viour might be useful.

Bowra, C.M. 1934. ‘The Occasion of Alcman’s PartheneionThe Classical Quarterly 28(1): 35–44 []

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

Crowdsourcing Fieldwork: A Neuroarchaeology Project?

How should an exhibit be lit?

How should an exhibit be lit?

This is a devel­op­ment of an idea I had last year after read­ing a post by Christina on a visit to the National Museum in Copenhagen. In short most museums I go to seem to have much darker gal­ler­ies for pre­his­toric mater­ial that clas­sical mater­ial. That has to have a psy­cho­lo­gical effect, but does it also have a physiolo­gical effect? Is the dif­fer­ence in light enough that there’s a dif­fer­ence feel­ing to observing pre­his­toric mater­ial to clas­sical mater­ial because of the room and not the con­tent? You could also ask sim­ilar ques­tions of European and Rest of the World exhib­its. Are African exhib­its in more dimly lit rooms, and if so what does this say about ‘world museums’.

It should be an easy enough ques­tion to answer; simply visit a range of museums in exotic loc­a­tions with a light-meter and then number-crunch to find the answer. That’s not very effi­cient though. It means arran­ging per­mis­sions, trav­el­ling to the museums, and log­ging the data. It could take three or four days in terms of travel to some places to log 50 num­bers. When it comes to num­ber crunch­ing more is bet­ter so is there a way round this? I sup­pose I could hire people to wander round museums for me with light­meters, but that would be expens­ive and my bank is already exper­i­ment­ing with new shades of red to print my bal­ance. It’d be handy if I could just find the data I want lying around the net some­where. Regular read­ers will know I’ve been think­ing about Flickr’s API a lot, and they won’t be sur­prised to hear that’s where I might have found the answer. A lot of people have been tak­ing pho­tos in museums and I think they could help.

It might sound bleed­ing obvi­ous that all of Flickr’s pho­tos were taken with a cam­era, but in the case of digital cam­eras Flickr can also store a lot more data. Attached to a lot of the pho­tos is EXIF data. If you visit a photo like this one, you’ll see there’s a more prop­er­ties link on the right side of the page. That takes you to a page like this one. It tells you the ISO set­ting, aper­ture and shut­ter speed for a photo. ((Usually — HDR pho­tos won’t because the have mul­tiple expos­ures)) If the cam­era is auto­matic then it will pick what it thinks are the best set­tings. The cam­era is set to manual, then the pho­to­grapher is still prob­ably going to choose what it thinks are the best set­tings. Therefore this gives a way to cal­cu­late rel­at­ive changes in light.

For example ISO set­tings come from the days when people used film for pho­tos. ISO 200 would react to light one ‘stop’ faster than ISO 100. ISO 400 was one stop faster than ISO 200 and two than ISO 100. So the ISO set­ting will let us cal­cu­late how many stops down the film speed is. The aper­ture is an odd scale because it relates to the size of the aper­ture of the lens rel­at­ive to the focal length. But it can be cal­cu­lated, f/22 is a stop up from  f/16 and f/11 is another stop down and so on. The same can be said for shut­ter speed You can go from 1/800 to 1/400 to 1/200 and so on.

Therefore, if you fix a datum you can meas­ure how many stops up or down from that datum a photo is from the EXIF data. This is related to the light in the image and the cam­era lens look­ing into a gal­lery or dis­play is a proxy for the human eye. It’s not per­fect, you’d want a lot of pho­tos but one thing Flickr has is a LOT of pho­tos. It also has the API, which makes it very easy to trans­fer the rel­ev­ant meta-data into a data­base for interrogation.

One reason I’m inter­ested in doing this pro­ject is that I have no idea what the res­ult would be. It could be emphatic, ambigu­ous or show that I have a very select­ive memory when it comes to light­ing. It might sound obvi­ous that you’d want to research some­thing you don’t know the answer to, but to gain fund­ing you have to show a like­li­hood of a pos­it­ive out­come — or that the meth­od­o­logy is at least sound. I don’t know if this is the case, so the pro­ject won’t attract fund­ing, but the API makes it cheap. Certainly cheaper than fly­ing on budget air­lines round Europe.

In terms of pub­lic­a­tion it seems like a good fit for Internet Archaeology. Internet Archaeology is mov­ing in steps towards open access. Given the… umm… eccent­ric atti­tude the AHRC takes to digital media, and the cur­rent eco­nomic cli­mate that’s a dif­fi­cult move they’re mak­ing. The fact they are mov­ing to Open Access makes it one of the most attract­ive ven­ues to pub­lish in aca­demic archae­ology. In this instance a data­base which can link back to the source files at Flickr would fit neatly into their hyperlink-friendly model. A bit of ingenu­ity with the SQL quer­ies and data­base fields and it should be pos­sible to make it a use­ful applic­a­tion for fur­ther research.

The biggest prob­lem I see at the moment is whether or not estim­at­ing rel­at­ive light levels from the ISO, aper­ture and shut­ter speed will be enough to dis­tin­guish between genu­ine dif­fer­ences in light­ing. There are other non-trivial ques­tions. If pho­tos are of the exhib­its rather than the gal­ler­ies, then will the arti­fi­cial light neg­ate any meas­ur­able dif­fer­ences? It would cer­tainly lose dark­ness in the peri­pheral vis­ion. How do I gather the data? Can I pull it straight from the EXIF files from any photo on the site, but would this be reas­on­able if the photo itself is set to copy­right? Would set­ting up a Flickr group for the pro­ject and try­ing to herd in volun­teers, or stick­ing to CC licenced pho­tos be better?

I think I could prob­ably set up a small-scale test of this over the autumn and then take it from there, Still, it would be help­ful if someone could spot all the flaws in this plan for me, rather than leav­ing me to stumble into them, so feel free to leave your com­ments below.

A tomb is a machine for remembering



Some blog posts are a long time in the writ­ing, but this sets a new record for me. Around May 2000 I was try­ing to think of a way of rip­ping off Le Corbusier’s quote A house is a machine for liv­ing in with regard to tombs.

It’s not a pos­i­tion I’d strongly defend. Tombs do other things as well. They mark ter­rit­ory to new­comers who may not know the local land. They’re a way of appro­pri­at­ing resources and pos­i­tion for the indi­vidual, if they plan their funeral while they’re alive.

If you want to be poetic, they also could be time machines. Once you have a set­tle­ment with a concept of deep roots, then it becomes pos­sible to think about pro­ject­ing your influ­ence bey­ond your own life­time. You can touch the future from a dis­tance, but if that works, it only works in the memor­ies of the liv­ing. It’s might seem a fanci­ful idea, but it’s spelled out in the earli­est sur­viv­ing history.

This is the dis­play of the inquiry of Herodotus of Halicarnassus, so that things done by man not be for­got­ten in time, and that great and mar­velous deeds, some dis­played by the Hellenes, some by the bar­bar­i­ans, not lose their glory…

One of my super­visors has already writ­ten some­thing along sim­ilar lines about reach­ing out bey­ond the human life­time. The archae­olo­gical record is messy and often not in fine enough res­ol­u­tion to dis­tin­guish between one gen­er­a­tion and the next. Finding those dif­fer­ences is going to be harder when you start think­ing about how people tried to blur those bound­ar­ies.

It’s an idea I’d like to return to, but for now I’m just mak­ing this as a note to myself.