Secrets of the Antikythera Mechanism: Session 1

wow what a great crowd fantastic on a wednesday morning to see so many of you here i'm john holler the ceo of the museum and i'm so delighted to welcome you or welcome you back on behalf of our trustees and our staff and our members many of whom i'm sure are here this morning and our amazing volunteers this is one of those rare days in computer history and we're so thrilled to have all of you here let me just say that if you're here ordinarily you're hearing me talk a little bit about our revolutionary series and that's in a bit of a hiatus now we're going to resume revolutionaries in september but we have a number of programs coming up over the summer that are not revolutionaries but are also very interesting like this so i hope you'll check the website for that information this whole day is made possible by a very special trustee who i'm going to introduce in a moment and who is going to serve as the master of ceremonies and he's also going to do something else that i need to do personally which is to thank autodesk for their very generous support of this event today you're going to hear about autodesk's role and a lot of what we'll be talking about and looking at this morning and we're very grateful to have autodesk do that a couple of ways that you get involved so you have these on your chair it's a card and you have a golf pencil that is a very analog way for you to ask questions but we do want to we do want to hear from you so as the morning rolls by please get your questions down on these cards we'll be coming through to collect those you'll see our guys as they're coming through and then you can hand your cards up and that's how you get involved let me remind you this is a two-part day we have a morning panel you're going to hear more about the details of that in a minute then we're going to have a lunch break lunch is on your own please visit the cafe downstairs we're going to have a few snacks and some water and drinks out here and then we'll reconvene in the afternoon promptly at 1 30. so please be back for that you may be tempted to see the babbage engine get cranked at 1 o'clock that's okay you've got a little bit of time to see that happen and then be back here at 1 30. now let me introduce the the man who's responsible for this today and who's going to serve as the master of ceremonies you know i think we're lucky at the computer history museum to have one of the best non-profit boards in the country they built an amazing institution they provide enormous support they help in every possible way and we have a trustee with us today michael hawley who is one of the biggest helpers of the entire prospect of putting programming together at the museum mike had a brilliant career at the mit media lab he joined our board three years ago he's been responsible for initiating a number of programs here on stage and in this auditorium he's the architect and ringmaster of a wonderful conference that happens every year at this time which is the eg conference down in monterey we're actually benefiting from the fact that eg is taking place because some of the people you're seeing today are on their way down there with him jonathan nulls michael reibrin and foley have all been eg participants michael's instrumental in putting that band back together and getting the state together for you please join me in welcoming my colleague and the division of the day i want to just put a tiny bit of color on in the morning you've got the artifact and a little bit of history courtesy of michael and nick and in the afternoon you have more of the exploration of the modern site both are absolutely fantastic filled with ideas and filled with interest and i think you're going to like it a lot i want to very quickly ask jonathan knowles to come up here and while he's finding his way to the stage i'll just mention that this strikes me as a real renaissance time for autodesk i was blown away they've acquired pier 9 in san francisco filled it with every kind of magical contraption gizmo you can think of biotech research 3d printing and lo and behold it turns out they've developed a fantastic interest in marine exploration of all sorts using every kind of innovative technology they can bring to bear so jonathan why don't you come up and tell us about your involvement here with this day and with the museum and everything else thank you michael so this is great to see so many people here today i'm sure all of you have heard of that product that autodesk created over 30 years ago called autocad right of course everyone walks up to us and says oh you work for autocad well it's 30 plus years later and now we make hundreds of products and as michael said we're involved in lots of different things including recent efforts into autodesk's maritime research and development and we're working with brendan and other people like him to explore to find out what's next in the world of design and engineering and that's why it's such a great fit actually for us to be here today with michael and talking about the antikythera mechanism what a what a fabulous thing it is you might see us by the way out on the bay and other places autodesk now has a couple boats who would have thought big software company like us but we do a dive team we're very active with all that and how appropriate that we are here when we consider that ancient greece was the cradle of technological civilization two thousand years ago uh how wonderful that we are here in this valley the current cradle of technology and civilization i think we can all agree that and specifically here at the computer history museum which connects our technology past to our technology future uh this is not new to autodesk actually so in 1791 the hms pandora which was the ship that the british had sent to pick up the bounty prisoners on hms bounty captain right the mutiny on the bounty captain bly all that and they sent him off they sent them off they picked up 17 of the prisoners and then started to bring them back and they hit something in the great barrier reef and sunk and lost the prisoners and all the crew and that ship was found in 1977 and an archaeological expedition was sent out there in 1983 about the time that computer aided design started to get going and this is isn't a picture from that particular expedition and they used that 19 it was 1984 by the time they got out there it was the 1984 version of autocad to actually do the digital work on that site and these are the actual screenshots from that technology all those years ago pretty fabulous stuff well this afternoon uh in the afternoon session after you hear from brendan you're going to hear from a wonderfully brilliant woman tatyana who's going to share with you some of the fascinating things going on today with regards to this we have just finished working with the u.s navy and the national park service to do a reality capture of the uss arizona in pearl harbor using lidar and sonar and photogrammetry software we're able to capture things capture reality and preserve it digitally and because it's the models we can do some real interesting things for example right here this is a coke bottle that's been sitting at the bottom of pearl harbor since 1941. because it's the data that we've also captured here we're able to 3d print that coke bottle more interesting though than that this next image you're going to see this is a cooking pot from the galley of the uss arizona which we 3d printed and put into the hands of one of the survivors who was on board the ship when the ship sunk and he just started to weep of course because he was now able to connect with something like that it was great that we were able to do this about a week after we finished the entire project one of the walls of the arizona collapsed and uh thank goodness that we were able to capture that before right before it it happened so um you know when i think of uh michael and when i think of his reconstruction of the antikythera mechanism i can't help but think of this guy archimedes right the original maker that's another big thing happening here in this valley right now is people now have access to amazing sets of tools and technologies that allow them to well sort of do what archimedes did back then and i fundamentally believe and at autodesk we do too that the world's a better place when we have more people doing design more people doing engineering and when they have access to tools to do it just imagine all the things that can happen i hope that some of you will go out after this today and and do something well like these folks here they there's a site called instructables that walks you through how to make things and there's a little company called open rov that lets you for about eight hundred dollars get the bits to make your own underwater rov and actually start doing archaeology doing science doing engineering in the water yourself there's no excuse for you to not be doing this or maybe for some of your family members to get them uh involved in in doing this so with that why don't we uh why don't we turn things back over to mike michael hawley and uh let's go back to ancient greece for a little while sound good okay is that a clicker here we go great can i have my picture please i think they're switching the computer feed what i thought i would do is take six or seven minutes and just give us all a framework so we're on the same page and i will tell you in advance i'm going to get a lot of bits of this story wrong and distorted and warped but the folks who are here can spend the rest of the day straightening it out for you there's andy kether it's that little fly spec islander as i've learned this morning antiquity from the greeks it's south of kythera is there a laser pointer on this there is somewhere kythera is here auntie keithra is there it's a small volcanic island in the aegean with steep coastal shelves a miserable place to be just a few sheep and annoying people and the story goes something like this in 1900 a greek vessel filled with sponge divers anchored off antikythera a fellow went down and he came up he was delirious he'd seen arms and legs and body parts and the captain figured well this knucklehead has been out in the sun too long he's drank too much oozo send somebody sober down and so they did and by sending people down this is what they were wearing at the time and this is what they found it wasn't body parts it was bits and pieces of statues and it proved to be the most spectacular shipwreck ever found in the aegean brendan calls it the titanic of the ancient world all of these miraculous things came up turns out the shipwreck was dated to about 65 bc give or take so it was more than 2 000 years old when found in 1900 and the archaeological authorities funneled all these artifacts back to the national museum in athens where i took these pictures and some of these things are just breathtakingly beautiful i mean marbles bronzes monumental pieces i'm sure somebody will have more to say about that later the site was visited just sort of tickled really by jacques cousteau around i don't know 1960 give or take but they didn't find very much and they didn't do very much there's a tremendous amount still waiting to be known in 1902 back to 1902 the curators were still tearing open wooden crates at the museum in athens and one fella ripped open a box and he pulled out the famous rusty hunk of metal that blew his mind and it looked like that and it blew his mind because it's a machine and it's not just a machine it's got gears and axles and things it almost looks like clockwork even though you can't see very much since it's two thousand year old rusted bronze i guess i think it's bronze but there's teeth and the thing about that is that you know clockwork didn't appear in western europe until 1000 ad 1200 a.d so this was an artifact out of time and it turns out it's so precise in its workings it's just fantastically sophisticated when when you really understand what it does this is a little like going underneath a pyramid in egypt and finding a black and white tv you wonder how the did that get there you know and what were they watching and inside as you will learn there's all sorts of gears and clockwork and it's unbelievable how it works and the man who figured out more of that than anybody else is with us michael wright this is a picture i snapped of michael in his backyard that funny little contraption the brass thing is a very sophisticated sort of sundial all i know is that it matched the time atomic clock synchronized time on my iphone to within about five seconds so suffice it to say michael really understands how to make precision things out of brass and there are i think very few people on earth who had the right mix of skills as as you'll see to be attracted by figuring out that device and demonstrating the sophistication of it by building a reconstruction of it so i'll mention just one or two other things about this in the spirit of hopefully getting them wrong and michael can sort them out and we'll bring michael up to do that um you twiddle a knob it sets a needle to a given day and uh let's say it's a perpetual calendar year and this little white ball in the socket represents the moon it twiddles around it's half white half black tells you the phase of the moon on that day of the year the position of the moon in the sky the other needles give you the positions of the five planets known at the time it's a geosynchronous i mean a a geocentric model not uh copernican that's understandable we'll give them a little slack for that but it's pin accurate to a quarter day per year it takes into account leap year and some other magic things on the flip side uh there's another dial that gives you approximations of when the next solar lunar eclipse could occur and then the final dial um this one uh here i think of is sort of like the cuckoo and a bavarian cuckoo clock um that one tells you the the city and the date of the next propitious olympic games because you know once the planets are in alignment and there's no eclipses to blot out your marathon you're good to go um so that's a very bad account of what this thing actually did and i would love it michael if you would come up and sort it all out for everybody michael wright what i discovered for myself nothing to do with school nothing to do with my parents who thought i was some sort of small monster i found i was a mechanic what i mean is i think with my hands as well as i hope thinking with my head and i think this is going to be important for our story because it may uh i think i'm the only person who's got up close and personal uh with the original bits of the antikythera mechanism who has that sort of uh practical experience and i think having that sort of experience you see different things you understand different things and it i went on to as part of my research work to make first one and then another model this is my over on your left is my first model in its present incarnation uh you'll hear more about that presently and it's full size of the original um and in most in the parts that exist of the original it's a fairly close copy obviously there's a lot that one has to well the blunt word is guess but guess intelligently i hope so here we go um i went to work as a curator at the science museum in london and that's an example one of the more polite examples of the sort of thing i was looking after heavy engineering um there's a steam engine sort of thing i looked after but it was uh while i was there i i got involved with this thing which you may recognize uh in its early stages uh some of you will know the name of alan bromley an academic academic from australia who set this whole reconstruction of babbage's engine uh going uh alan had become a babbage scholar and he um he came over to study the in england the remaining babbage artifacts and babbages notebooks drawings and so on and when he'd finished looking at the drawings in the library he said to one of my colleagues over there okay i understand what it's meant to do but i can't understand how it could have been made so my colleague in the library said go and see a chat called michael wright so we alan and i got to know one another and from talking about how you'd make a babbage engine we got on to trading all sorts of mechanical curiosities and um there came a day when i told him about my interest in the antikythera mechanism and what did the rotter do he stole the project from me because he had time for research i had none he had a certain amount of project money i had none he had caught blanche with his department to study whatever he found interesting i had a specific um uh instruction from my line manager that i would have nothing to do with that ancient greek thing he couldn't say antikythera and uh um even he said in my spare time so this gentleman was a bit of a rogue in private we all knew so i used to say i said to him all right dr b i won't tell you his name nope no name pack drill um what does how far does your line manager try to control what do you do with your spare time he was trying to get me to sign a legal undertaking so he just went beetroot red and i left the room without signing his undertaking and that's why i was never promoted um the um anyway here the this thing uh oh there's a picture on the left of alan bromley with the beard uh reg crick the man whose tie is hanging forward the draftsman who did a lot of the drawing for the parts of the reconstructed engine that believe it or not is me leaning over the table at the back uh in the days when i had more of a head of hair and but you can recognize the the chain for the pocket watch the um so uh alan comes is going to come into my story again in a moment a brief digression i wonder how many people recognize this part of the difference engine and i wonder whether for your example this component one of the one of them any of them has given you a bit of trouble uh if so i have a story to tell about that in private um it'd probably better be in private um okay uh i uh going back a few years fairly early on in my time in the science museum this paper came out late 1974 gears from the greeks was the first thing i ever discovered heard or read about the antikythera mechanism uh it was absolutely stunning um gosh i thought i'd like to be involved with something like this uh but um this professor price seems to have done it all he's sewn it up the only problem was i couldn't understand a lot of what he'd written a lot of his argument i thought well this must be my fault i must be stupid um actually i was stupid because well i'm embarrassed to tell you how this turned out um i had to leave this aside because i my steam engines called um but and and things and i i but i came back to it about 10 years later oh that's just a picture of the museum store um in athens um the it wasn't a matter of tearing open a box it's a matter of kicking over bits and pieces on the floor i think to find the uh the parts of the mechanism um shall we say turning them over um and uh we've seen that already so we'll go through it uh i want to talk about this we're talking about where the where the mechanism came from all i'll add to what um uh mike said if i can do this is uh on my map here here is andy kethera there is crete there's the peloponnese this corner of the peloponnese is cape malaya and ancient sailors had a saying which has come down to us um if i can do it malayas de camps us epilathuton if you go around cape malia you can forget about getting home it's a dangerous part of the world so it's not surprising that there was a shipwreck there um after all what you've got here is a rock in the middle of a busy shipping lane um uh and the the uh the wreck see uh looks like it looks so the ship positively drove against the cliff and went down onto a ledge straight below the cliffs uh you'll hear more about the wreck itself from brendan in a moment so i'll go light on that um the ship uh was almost certainly uh heading west from this part of the world uh coins from the ship gave us a pretty clear dating to 70 to 60 bc and indicate a recent port of call on this coast of what's now turkey and most of the artifacts found in the ship come from this region most of them were probably contemporary with the wreck a few uh like this rather special fellow were thought to be several hundred years old by the time that uh they were shipped so it's a mixture of luxury goods and the puzzling thing that i'm here to talk about um is uh part of that luxury cargo don't let anyone uh persuade you that because it was on a ship it had to be a navigational instrument there is no way of using this thing for navigation let's hit that one on the head um that's more like what it looked like in 1902 uh the bit that uh mike hawley showed you uh this piece here as you can just about recognize the profile you can see a lot less of the detail but you can see some bits that were missing by the time mike hall's photograph was taken particularly uh some woodwork which is part of why the box for mine is the strange shape it is i've taken account of that um okay well ten years after i th oh this is price's reconstruction of the thing what we have is a wooden box with a bronze gadget inside it i mean the wooden box frames it um a bronze style front and back on the front dial two rings the inner one is uh the zodiac divided into 360 degrees uh so celestial longitude for those of you who know your astronomy um the the outer ring is a 365 annual day annual calendar and i'll come back to that uh on the back two uh two more essentially calendrical dials the whole thing worked by turning a spindle at the side um through gearing contained inside it okay that that's probably that's a summary of prices uh reconstruction and so far that's okay or i believe all of that but none of his details right almost none uh and we'll probably come to that i had to go back to reread price uh as i say uh about 10 years after that paper came out when i got involved dealing with oh i didn't mean to do that wrong gadget dealing with this this thing which came into my museum which we believe is the second oldest set of gear wheels in the world so far um and i designed and made the reconstruction uh it wasn't my business to make reconstructions at the museum but uh the workshop was on a go slow and we were having an exhibition so uh you know workshop manager said well first of all we'll have to wait till the right draftsman's free to draw the parts oh that'll be six months oh and then we have to find the right workmen in the workshop to make this thing you know it's not everyone can do it so i ended up saying well get lost i'm taking a week's holiday and i came back with it home made at home um the um this is professor derek the solar price with a reconstruction that was made for him which is all wrong um but but he had every right to be proud of it because uh you know he well okay um it was a stage um i met price when i was working on that other gadget he actually came to see it and me and my colleague who was working on it with me my colleague was talkative and i hardly got a word in edgeways with price and a fortnight later he died don't think it's a causal relationship but it means i could never ask him any questions but by then i had realized why i hadn't understood his paper a lot of it is rubbish um you may think i'm insulting the us of a because he was a professor at yale but he was english so i'm allowed to do it um um so anyway what happened was i i said alan bromley took over my project and i had to run with him or be left behind completely so we both went to athens we got permission to study the thing this is again believe it or not me uh about 1991 and that is that big fragment of the mechanism uh the big the face you recognize downwards i'm looking at the back of it um and we uh alan took a lot of photographs i went all over it with not just this magnifier but all sorts of magnifiers and uh got very down and dirty with it and uh measured it in a ho using a homemade measuring jig oh that's oh yeah okay and um then devised homemade apparatus to allow me to do linear tomography with it which was necessary to separate out what happens in the different layers i told you this is all embarrassingly low-tech linear tomography was devised in the 1920s for locating shrapnel in the human body and it worked very well for separating out the layers of cogs in this thing up to about eight layers thick um that's a photograph of the thing is published in a book in 1903 and therefore that's that was photographed in 1902 that's photographed by alan bromley and me in about 1991 you you see how bits have gone missing let's go uh if we just go back watch the transition again and that's one of my radiographs showing uh a different difference that's a straightforward plane radiograph showing different layers inside which is the sort of stuff i've worked from you've heard i'm sure about high-tech oh the jargon is cutting-edge uh computer-aided tomography that's been done on it i've had nothing to do with that i've been excluded from it actually and i have no access to its results so all that i've done has been done with more well the old-fashioned way as they used to say in the navy so in 2000 by 2002 i was ready to model the front of the instrument uh and 2004 i'm starting to think about the back uh a conjectural complete re completion about 2005 which is beginning to look recognizable uh small small modifications in 2006 and 2008 when the other guys uh in in in the story uh published and uh i was able to modify things a little bit but um the general perception is that it's what the other guys have done the antikythera mechanism research group that have told us all we know now well all i'd say is if you look hard you'll realize that actually their work is built much more solidly on mine as a foundation than they are admitting um give you some perspective my model took me about a thousand hours to make working at nights and weekends uh um and um i suppose some of that was thinking time um but it's all made it's made largely by hand tools most of it is made with a set of tools i could put in the pockets of this coat um plus a bench vise um and um uh when the group published their results it took me an afternoon to modify what i'd done to fit with those parts of their results which i'm sure are right so the alteration between my provisional reconstruction and what we have now is quite slight what the group have done magnificently is and the author of the system is here i won't embarrass him by naming him unless he asks to is they've done a magnificent job of getting images of the surfaces which allow them to read the very fine lettering on the surfaces of the original fragments which is very very hard to read i got an epigraphist on the job and he started and he gave up so that uh was um the end of my effort on that um then i built a new model uh about 2009 which will come back to you later you i would bring that one to show you except that it's on display in athens at the moment that's the story of my model making and now i'm going to um it's an astronomical gadget so i'm just going to remind you the very basic astronomy that you need to understand it um uh and we start with this rather fanciful picture of the night sky uh here is our ancient astronomer looking west that's the new moon uh so he's obviously looking west um and it's in taurus the constellation taurus which means it's spring it means it means the sun is in the next constellation down aries which uh is around the the the vernal equinox the spring equinox so there there's there's taurus there's gemini above it and the the stars form as you know a fixed pattern uh which rolls over us night after night but shifts a little is shifted a little every night so that if night by night the stars we'd see at any measuring point say the horizon at sunset are slightly different so a few days later if you look at that one now watch the uh taurus is a bit lower in the sky at sunset the moon instantly moved long up but never mind so and it shifts night by night until if you watch after 365 nights or thereabouts the pattern of stars is exactly as it was when you started so that's the year the year is to do with that shift in the way the uh we see the stars against any fixed uh register um let's go back to that first picture and now consider the moon here here is um a thin crescent new moon um it's a day or so old let's suppose um and a few and i say it's moving uh moving up to the left at sunset until finally he looks the other way he looks east just before sunrise and there is the new moon now by the by by the playa dis pleiades in in taurus um and it's about 27 days later if i go back to the last one um the one before it here here was the moon early in the month at the end of the month it's back in the same place in the sky but you see it of course the old moon you see in the morning just before sunrise um so that's one form of month but there's another four that's that's strictly the sidereal month or what comes to nearly the same thing for tropical month and maybe we'll disentangle those at question time if you want um the go a couple more days and there is the next new moon now by the foot of one of the twins in germany uh and that's 29 and a half days roughly 29 or 30 days so that's a different sort of month and that's the sort of month i'll be talking about mostly in what's to come properly speaking it's the synodic month in other words the month measured by the sun's position relative to the sun okay so we've got years we've got months both defined by the sky and the numbers are awkward uh there are there are the numbers approximately uh consider the top and bottom ones 365 and a quarter days 29 and a half days months don't fit into years exactly it's annoying particularly as for calendrical purposes um all the greek city-states that we know about their calendar used a loony solar calendar in other words they worked both by the year for some things i mean the seasons go by the year the time when it's suitable to sail the times are suitable to reap your harvest they go by the year administration civil matters tended to go by the month if you had a debt the interest was payable at the new moon uh we get that from aristophanes um and uh but there's no subtlety in this astronomy at all you see it's just a matter of observing what happens in the sky and keeping a note and counting now this is a thing that particularly the babylonians were really good at in mesopotamia and they kept their records on tablets of clay like this one this one happens to tell the story of the flood but never mind um it's it's an illustration sort of thing and it shows the sort of size of these clay tablets they're handy size and uh um and the but they kept astronomical records from a very early date and fairly thorough ones and uh they were really interested in counting babylonian astronomy is um it's that one again babylon astronomy is really it's not has they had no concept of kinematic motion what was going on in the sky they kept but they were interested in numbers timing of events so we get this thing which we know by greek name the metonic period relation but it exists in babylonia beforehand um if you multiply up you'll find not those approximate figures but if you actually count 19 years contain all very very closely 235 months it's um synodic months that's um a a a very useful period relation as we call it um years to months and the the the other one is really um it follows directly from it that 19 years the 254 tropical months to the same approximation it's good to say well it won't get the position of the moon according to this thing won't go wrong by as much as one degree in over 500 years it's good um the uh so now we're ready to go to the instrument okay that was the astronomical interlude the um on the first one um here's the back of the instrument and i'm starting with the back because we know more about it really than we do about the front it's less badly wrecked um the top as i say there are two calendrical dials the top dial is absolutely a straightforward calendar um straight away each of these divisions is a month a synodic month they're all named uh they go round in five turns on spiral from there to there uh there are 235 of them 19 years uh the the beginnings of the years are marked now because there are about 29 and a half days in a month in your calendar each month has to have either 29 or 30 days because there are because if you multiply that up by 12 you don't get as much as a month as a year get about 300 354 days some years have to have a 13th month this array gives you a plan for which month is a full one which one is what they call a hollow one uh with only 29 days and it tells you here which day of the month is to be left out to keep things as even as possible it also tells you which years should have that 13th month so this is as i say a straightforward calendar scheme um the little dial here this is the one which people have remarked on because it has the different greek panhellenic games i don't know whether it's clear enough to read perhaps it don't know whether it's the my photography or i think it's more my photography than my engraving that's at fault that uh you can't really read that says olympia but the different greek games happened either on a two-year-old or on a four-year cycle so on a a dial with a pointer going around once in four years you can put them all in uh people have remarked on this as being an odd one out it's shall we say social not astronomical but i disagree i'll come to a very good astronomical reason why you should have um such a um a four-year counter here and anyway it's a useful reality check um because everybody knew whether which games would there would be any particular year so it's a very quick way of checking you've set the thing to the correct year the other little dial on the other side is conjectural amongst the inscriptions we we have a note concerning the 76 year cycle but on the bits that survive we don't have any indication of it well this part of the dial and anything any gearing that might have been behind it is missing so uh conjecturally i the 76-year cycle four times the 19-year cycle has to be there somewhere and this is the best place to put it so that's where i've put it um it has two significances one is if you remember the numbers everyone knew a year was 365 and a quarter days roughly um if in 19 years therefore you've got an untidy number of days something plus three quarters by multiplying the whole lot by four you had a period relation with 76 years however many months it is four times 235 who's quicker than i am uh and a whole number of days uh very satisfying the other uh purpose of this uh um period relation that we call this the calypic cycle is that uh calipic cycles got used for um things like astronomical chronology in much the way we would use a century it's a 76-year interval so you can talk about the second first second third calypic cycle from when they started in 330 bc um so that's that's that dial holy calendrical let's uh back to the full back and zoom in oh we're we're going to zoom in on the lower back dial and this depends on another period of relation which was found out in babylonia and then came to the mediterranean um uh don't be frightened of the name actually that's a modern name well given it by the 18th century astronomer at edmund holly never mind um he made a mistake it's it's a babylonian word but it doesn't mean what he thought it meant um the significance is this if you observe an eclipse and you note exactly the style of the eclipse how full was it which way was was occultation um so on you you can be pretty sure that 223 months later there will be just the same style of eclipse only it'll be about a third of a day later you see there's this one third of a day built into this cycle so after 253 months and a third of a day you uh these pattern repeats um i won't go into what these other quantities are but these are what make the eclipse cycle work we can talk about them at question time if you're interested but i'm not aware you really came for an astronomy lesson i'll just mention that you will come across this uh anomalistic thing later you have to you gotta have it um the but so we go to the lower back dial and here is a scale of 223 months set out in four turns and but the the the only entries on on that are where we can expect an eclipse in the uh in the pattern um and it tells you whether it's an eclipse of the moon or sun uh in that month or both and it tells you what time of day to expect it now as i told you it'll be a third of a day later each cycle so we've got a subsidiary dial which adds a correction that's the uh the greek letter eta standing for eight this uh these two symbols mean sixteen so it's telling you how many hours to add to the time given in the main entry uh to get the eclipse time right in the particular cycle we're in this pointer moves from one uh sector to the next in a full cycle so and there are three sectors so um what this does is it tells it doesn't be care be clear about this it doesn't tell you you will see an eclipse it tells you the possibility of there being an eclipse of course many eclipses due of the moon which happens exactly at full moon may happen during your daytime many eclipses of the sun may happen during your night time and we all know that eclipses of the sun are only visible over a small geographical region anyway so um or the nature of the eclipse you see various with where you are so um you don't see the whole of the pattern any time but this gives you the possibilities to look out for by analysis of the data here um and the left side of the dial again is reconstruction this this side we have only a chunk of it from about there to about uh yeah we have about a third of the left right side of the dial all together uh in two pieces um the tiny third bit um by analysis of that data it can be shown that this sequence which isn't perf it shifts slowly in time because the saros cycle isn't perfect it's only approximate and uh so you can match this sequence best to us a sequence of what we believe were actual eclipses that happened started in 205 bc uh now i don't think we should then conclude that the instrument was made that early i think it much more likely that what was going on was that the maker of the instrument or the designer of the instrument took a pre-existing record of of an eclipse sequence and it so it's it was old data when it was built into the dial established data and perhaps the designer didn't realize how the pattern shifted with time and would become uh would start to go wrong in due course anyway how long was he planning this instrument to go on working for most gadgets are designed with a a recognition that their lives will be limited this one survived longer than most um okay so that's the back dial now we're going to talk about the the front uh but first i'm showing you what you see with the back removed firstly you can see i made this model out of scrap metal that's an office name plate used as the frame plate uh i didn't lever it off the wall uh um but the what i wanted i want to make several points about the displays i've just been discussing the first point i want to make is there's a serious design blunder okay let's go back um when there's a sort of sliding thing uh whether it's the whole point or not is uh another matter there's which is engaged with a traveler that travels in the slot so that as time goes on the slider tells you which turn of the scale to look at in each case here my slider is indicating that you look at the uh well here the uh this this part of the scale here this one sorry i can't hold it straight enough the next to last one um now if you wind on with carelessly and come to the end of the slot where it stops being a sort of spiral um and it's not a true spiral it's a set of semi-circles by the way the uh and if you go on winding you'll have a i did it within about five minutes of setting up this display it's easily done because you tend to be looking at the front as you turn the knob and then suddenly you've caused trouble so that's a serious design blunder in my view second thing i was going to say about it is um the uh the astronomy is not subtle i've tried to show you it's absolutely almost bonehead simple it's a matter of watching the sky counting recording events the third thing is the gearing that drives those pointers is once you've got gearing at all um which seems to be a hellenistic invention um from somewhere around 300 bc as far as we can judge um one once you uh once you've got gearing this is absolutely straightforward too uh the gearing to drive those pointers there's so there's nothing subtle about the astronomy there's nothing which is essentially babylonian there's nothing subtle about the the mechanical the mechanization of it i'm not trying to drag the instrument down but i i am trying to provide an antidote to some of the hype that you'll see in print which suggests this was an amazingly sophisticated device perfect in its conception and execution and just unbelievable nonsense you better believe it because it's there and if you find it incredible then you need to adjust your set um the uh so far it's actually quite unsubtle just wonderful that we have evidence that this sort of thing was done at the time now we'll go to talk about the front and i'm going to talk about a bit you can see here which although it's embedded in the back has to do with the front we at least have enough of the front dial to know what it looked like uh here's a photograph of it again from my model because it's easier to understand the inner ring for the zodiac divided into degrees uh the outer ring uh for an annual calendar now this is um uh so you can think of it as a sort of flat projection uh think about the inner ring as a flat projection of a celestial sphere the um the the outer ring uh is for a calendar that we call the egyptian calendar of exactly 365 days in every year uh this was a very good calendar for astronomical purposes because it's utterly predictable there's no fiddling about is this a leap year or not because they didn't have leap years the leap year was as far as we know uh first formally introduced in julius caesar's calendar reform sometime after the antikythera ship sank um and uh so but what they knew perfectly well was that the year was about 365 and a quarter days long what they accepted was that every four years the astronomy would slip a day against the calendar or vice versa in other words the uh the equinoxes or on the solstices would happen a day later in their calendar and to allow for that the calendar ring is movable i'm sorry that's the wrong button there we are so there's the calendar ring taken out of its groove and you see a series of little holes 365 of them um and a pinhole in the ring and there's the pin that actually marks new year's day in the calendar and every four years you'd take the pin out shift the ring round one day and put the pin back and that's why you need a counter of the four years which we we tend to think of as showing the olympic games or whatever nonsense it's for check for doing this um so uh that's the the front dial now what what happened uh i'm showing you this has got out of sequence i think but anyway i i i'll i'll pass over that and come back to it i need ah that's just that i'm just showing you uh why i tend to illustrate things with pictures of my model because the original really isn't very easy to understand that's the view i was studying on the table in the earlier slide and very puzzling it is um but we're going to be talking about a bit that's just here uh these these wheels are sort of broken in half like somebody sharing a set of biscuits the stuff is absolutely terrifying to handle when i first went there uh the fashion in those days was to wear cotton gloves so i got my gloves out and the curator said mr wright thank you for thinking of bringing gloves but take them off again please less of it will come off on your bare skin it's like handling very heavy dark green flaky pastry um so uh we're going to be talking about this bit here in a moment but first oh okay we let's let's let's do it this way um i'd think i'd forgotten i'd remodeled the talk before i sent these slides off to to dag the um uh we know i mean price got us this far that on the front dial we have pointers going around indicating the position of the sun and the position of the moon and the date either two or three pointers come back to that um now the moon is very obviously tricky in its motion it doesn't take much subtlety to spot that it moves at an unequal rate across the sky night by night it moves sometimes faster sometimes slower with a pulse that pulse is not quite an ordinary month long the the length of the pulse is actually what we call the anomalistic month ancient uh thinkers tended to regard the most natural and proper motion as being uniform motion in a circle and when they saw a thing like the moon moving sometimes faster sometimes slow they said ah an anomaly this is what we call the lunar anomaly or uh now that we have several the first lunar anomaly but for them just the one and uh so the moon sometimes goes faster then slower the point at which it is at its fastest and at its slowest moves slowly round the sky because i've said that period is not quite a month uh so to model the motion of the moon accurately we need to imitate the pulse and the fact that it shifts round the dial slight uh slowly this is how we do it the the anomalistic this you recognize as the gearing you saw earlier in the back of the instrument uh here is the center of the uh hand on the eclipse prediction dial that's the center of the hand on the calendar dial so you're looking at it with it's the top is to the right um and on the way the gearing com the the the the gearing feeds through from here so on the way to driving the uh pointer that represents the saros cycle we have this big wheel we have to because the saros cycle is 223 months that's a prime number which means if you're going to make it into gearing you've got to have a wheel at least as big as 223 teeth 250 or 669 or whatever um uh 203 it is now what the designer has done is to build his little pulsing gadget onto this and you'll see why he's built it on in a moment um here's that wheel seen in perspective the motion the motion on this point square that i'm pointing out now is at the end of the train driving the month pointer by the way that's a design disaster perhaps i'll come back to that um the um so this as you drive the thing forward this revolves at the right speed for an average month but it doesn't go to the month pointer it comes here and it has a wheel on it and that drives a wheel with the same number of teeth but what i want you to notice here is if i go back one is that this stud on the wheel is stepped so this wheel and the one that's going to go on top of it like that turn about different centers the bottom one has a pin in it the top one has a slot in it that embraces the pin and so this wheel goes around at a steady speed one average month so does the bottom wheel here the wheel on top goes around again once a month but now it has a pulse to its motion at the point in its motion where the pin is at the inside of the slot it's going faster where when it comes halfway around and the pin toward the slot towards the center and the pin is at the outside of the slot it's going slower so um then we take that pulsed motion back to the center to a separate coaxial spindle in the center here and it's taken down and through to the front dial so there's the pulse built into the motion now what about the fact the pulse has got to shift round the dial well that's why it's all built onto the oh that brace just holds it all together uh now you recognize the assembly this wheel is it's devised so that wheel goes around the round in the box at the right speed for the anomaly shifting around the front dial that that is quite subtle work and this uh this is an interesting piece of design and so far quite a good one um so let's look at the front dial with just the sun and moon pointers and it rather looks like i've put tissue paper in there but it's done through some rather primitive photo retouching system um which is all i could do um low tech as i said so here's here's the moon pointer that's the place of the moon in the sky here's the sun pointer this little black and white bead shows the phase of the moon it's simply working on the relative motion between the two uh it's utterly independent of everything else inside the box it purely works on a pair of gears hidden under this dome which you can think of as uh as representing the earth at the center of the greek universe the greek cosmos oh one other thing here um we have to show that the date so this could be an extension to the sun pointer except i believe that the the uh the sun also has a pulsing motion it's less exaggerated than that of the moon it's slower it's better organized it doesn't shift around the dial not not as far as ancient astronomers was concerned anyway but uh if we build that pulsing motion in as i have we have to have a separate pointer without the pulse for showing the day of the the year there is another way another scheme for doing that which you may have seen in print um there are people who believe that this style was unequally divided to allow for that uh solar anomaly well i don't believe it was they they haven't got enough of the dial to be quite sure that their evidence shows what they say it shows uh the juror is still out frankly we'll go on what this stage i used to feel i was on very shaky ground i used to have to start um to make to explain myself to argue for why i've reconstructed a set of pointers for the planets i don't have to do that anymore because the ongoing job of reading the inscriptions on the instrument uh shows that i was right it did show the positions of mercury venus mars jupiter and saturn the naked eye planets the ones they knew about so we have uh five pointers of the planets uh what we think of the pl as the planets they included moon and sun as planets so we've got seven and an eighth pointer for the the day of the year um the mechanism for driving these planet pointers is almost whole almost wholly lost it would have been straight behind this dial and in front of the fragment that we have behind it you'll see the relationship of the two if you come to my demonstration in the lunch break when i'll strip the dial out of out the thing and you can see the space inside but it may be that the mechanism for the point has dropped out complete uh it's not my telephone the um uh but and if it did possibly it's waiting to be found i fear it's likely it's to fall into a lot of very small pieces and we'll be much more lucky anyway for now anyway we have to just use our imagination to reconstruct what's missing and there are two ways of doing it so far suggested um first of all you have to understand the problem uh in a an oraly which many of you will be familiar with a model of the heliocentric universe the copernican universe with the sun at the center it's a pretty good approximation to have the planets going around in circular orbits at uniform speed but in a geocentric planetarium like this it won't do at all because what we the main thing we know about the planets after all the name planet means a vagabond a wanderer main thing we notice is they have a very strange motion in the sky um here's an illustration of now i'm embarrassed to say i've forgotten what book i take took this from but i'm i uh this is charting the retrograde motion of a planet um some date in the 1950s um now the planets like the the sun and moon we think of them rising in the east and going to setting in the west but they're always crawling the opposite way they're crawling from west to east against the pattern of stars so are the planets and uh but although they go on average from west to east see this was may the 13th there comes a point where the planet stops dead and actually and goes back the other way against the pattern of stars it's this is in capricorn and then stops dead again and goes off forward this is what we call the retrograde episode and anyone who follows the rubbish in the newspapers called a horoscope will be familiar with the term uh retrograde episode uh and possibly with these moments the stationary points or first and second stations so a a geocentric model of the universe that doesn't do something like this simply doesn't uh you're just not in business so nobody's going to want it it doesn't show what you see in the sky at all so uh we have to find a way of explaining this bizarre motion of the planets now remember that uh the orthodoxy was that uh motions should be uniform circular motions the first news we have of a tolerably satisfactory solution seems to date from around 200 bc it's reported much later but that's when the man who's involved with it apollonius was alive and he's combining two circular motions to get the effect we want e is the earth m is a point that is traveling around the earth with a steady motion which is the average motion of the planet p is the planet itself traveling on another circle around m so if i can do this this makes loops like this as it goes around the sky and if we get the speed right at the point where at the moments when p is on the inside it can be going that way faster than the point m is going that way in other words we get the appearance of the planet going backwards which is what we want um and it i believe this is what was built onto the front of the instrument on top of what we see here this is this big wheel goes around once a year and i'm showing how i've built in this model what i've done in the second model is slightly different and actually rather better but the same in principle i mean when i say better i mean it's mechanically better and it follows the traces of the original more closely i built this in the first instance really as a demonstration of what was possible rather than an attempt to reconstruct exactly what was there you'll have to remember back in 2001 2002 when i was designing and building this the atmosphere was that it's just incredible to think that the mechanic of that time could have built such a planetary model and i was trying to show uh that it wasn't so um so here you have that wheel that goes around once a year and that's an epic cycle as we call it the the circle moving on top of the uh around for venus here's a little one for the sun i'll come back to that in question time if you want that does the slightly unequal motion of the sun on there i'm going to place an epic cycle for mercury mercury and venus the inferior planets are the ones on the inside track between earth and the sun uh they they go round on average at the same speed of the sp sun but turn about the the epicycle turns about its own axis um at its own peculiar rate so that's easy and there's the gearing to do it um and there are the levers that pick up the motion and transmit it up to hands on top sun mercury venus the superior planets the ones on the outside track outside earth mars jupiter and saturn have to be treated differently because the model is the other way out here the epicycles travel at the rate of the sun but they go round the earth at their own peculiar rates so each has to have its own big platform to go around on so three different units but they all work much the same way and for example here is the one for jupiter um this is um uh this is holy conjectural um but it works uh the frame plate well uh what it comes to in the end is that there is the epicycle which drops in there and is driven through a chain of gears and it works and it works well we put it together that's the underside that's it put together uh that's it uh even more put together with the stationary wheel in the middle that it crawls around uh there it is in the box with its lever on if you built it all up without the box you get a monster that looks like this like a sort of multi-tiered mechanical wedding cake that seems to me to exaggerate the height of it and the complication it's all inside that box there and you can see you can see later more recently i i did this back in 2001 2002 ten years later somebody came up with another way of doing the planets which involves fewer moving parts building on there uh two sets of people came up with the idea simultaneously and i've to be fair-minded i've taken illustrations from both of their papers without without permission but never mind um you won't tell on me uh the um now the this this is a quite an ingenious way of doing doing getting nearly the same effect it's a development of that thing i showed you for the lunar anomaly with the pin and slot mechanism here we have a big thing that rotates at the rate of the sun what the pin and slot mechanism does is it subtracts a motion for these wheels which uh go through and carry the pointers so the the motion of the once a year motion of the sun is subtracted uh by these wheels at a varying rate and the point where the pin is at the middle of the slot and that motion is fastest the subtraction is so great that it makes the driven wheel in the middle go backwards so it achieves a retrograde effect the difference between theirs and mine is this um that um oh that's a scheme of it um simply the same thing oh they've done the inferior planets both thoughts suggest doing the inferior plants really the same way that i did because it's the least complicated for the inferior planets um the the now the difference is this that with the i chose to complicate my model to show uh what was possible and to show that by using compound gear trains which i can fit into my sort of reconstruction you can get very very good period relations for the planets indeed they're all as good as that period relation for the moon that i mentioned earlier in other words all my planets their mean position doesn't go wrong by as much as a degree in over 500 years and frankly though i set myself that's impressive the other method of doing it obliges you not to use compound gear trains but use simple gear pairs and you have to accept much less good approximations for the motion and particularly the motion for venus is absolutely rotten um here but the latest news is this the ongoing reading of inscriptions this is a thing which alexander jones very kindly told me ahead of publication he's read the name of the planet venus tis african dishes and the number 462. so what uh the what it shows is we're dealing with again as before with babylonian ratios which go back very long time and therefore though because they they taken a very long period they can be very good um the um don't worry mike i'm nearly at an end the um uh but the babylonian ratio for venus is one one the good one is one one five one seven twenty and one one five one is bad news because it's a prime number so you've got to approximate this ratio and approximating it this is in the latest paper that i've published the approximating it by means available to the hellenistic mathematician the best approximation you can come up to come with two is four six two that number again to two eight nine two eight nine is 17 squared so we have numbers that can factorize and can be uh mechanized in a compound gear train not in simple gay appears but in a compound train the simple gay appears have to rely on this very poor approximation eight to five and that's embarrassing actually because it means that only after a couple of years your venus is going to be in the wrong place um now in fact this approximation is good enough to satisfy my my criterion it's still at least as good as the approximation for the position of the moon good to over less than one degree in 500 years and with all the babylonian numbers you can do the same thing if you have uh one planet with a compound gear train the problem is you have all of them with compound gear trains it may be that further reading of the of the inscriptions will throw up other numbers which will either prove or disprove this point so i'm telling you really the latest thing as far as i'm concerned and the wonderful thing is that these compound these babylonian ratios can be fitted into compound gear trains which can be put straight into my model instead of the gear wheels i have with no other redesign than to just change the gear wheels so i think i've come as near to the truth with this as present information allows and with that and with that view of my slightly cleaner model now on display in athens i'll stop you have a short movie oh how have i time mike's kindly allowed me uh three minutes to show a little video uh if we could have it please now this was made by a friend of mine for an exhibition in florence so the captions you're starting with what you know this is that fragment a so his captions are both italian and english he made this at the same time that i was making that second model and i gave him the data as they came available so it represents pretty closely what's inside my second model it's like a sort of reversed explosion here is the gear train uh leading from the the sun to the moon uh there is there's the gearing for the back wheel um i haven't explained why the gearing for the sun and moon is a disaster but maybe that'll come up later um so there's the gearing for the back dial all coming together now i love the way the the little cotters fly into place so uh upper back to our lower back dial top is to the left in this case um now you see the conjectural reconstruction of the planetary motion coming in uh the planetary motion plus uh that pulsed motion the the solar anomaly those are the inferior planets here comes the sandwich for mars now jupiter exactly the same pattern only with different numbers of teeth and different geometry for the epicycle and the same again for saturn there's the front dial and a set of hands i'm sorry i'm standing in your way i haven't just realized stupid of me um my day of the month dial is a conjectural edition which we might discuss if you want later uh there's the lunar phase which is by no means conjectural um it's for real and mike yes if you watch carefully you can see some of the there's venus going sorry saturn going retrograde here is um jupiter going retrograde and that's what you would see on my model if you could only turn the knob at a steady rate um i think my friend who made this animation is cleverer than i really uh i can't do this sort of stuff um um one turn of the knob is something like 72-73 days it's um it's very odd okay unbelievable okay stop it now we're scrambling to save time what i'm going to propose is that we not do the questions there's only half a dozen and you can ask them of michael during the break nick if you would please come up um nick alex opolis is an emeritus professor in computer science and electrical engineering from uc irvine with a broad fascination with all things ancient scientific and technological and he's got about i think 20 minutes of uh discussion to give you a broader context for where this and other machines came from so nick all yours thank you this is and they're moving forward okay thank you um how did it all begin well because of the 20 minutes i will be very quick but i will cover at least 20 000 years always the simple folk like the sponge divers are in simple clothes and the government officials of course take all the credit at the end of the day at the top and i wanted to just demonstrate this is from the national museum of athens it's a book and it has this picture and i want to challenge you to think about what do you see i see pure technology some of you will say well i see technology right there some of you will say i see art and part of the mix is that the word technology comes from the ancient or modern greek word technology techni and logos where the meaning actually is a make useful things with logic analysis with aesthetic value so in a nutshell this is amazing technology as well because imagine the science or engineering methodology to do to do such a kind of a statue and i'll get back to this later but how did it all begin and i will take a little digression it all started this morning for all of us when we got up and get ready to come here we went through a very simple routine we do this every day we ate breakfast we got ready we got dressed maybe because we have become a little bit robotic we had to touch our cell phone see who sent us a message we sent messages we looked at pictures etc we got in the car maybe we used gps and we came here what a beautiful routine we go through this every day for different goals in this routine we touch a huge number of objects things we touch them consciously subconsciously it's our life we never think how those were made who amongst you is honest enough to tell me that one day you looked at your fork and you said who is the engineer back then who figured out how to make this fork i heard about the engineer who made an assembly line to make millions of these are there affordable and cheap when you dial a number to call on your cell phone do you ever think how is this happening what's in that little thing the cell phone we hear about chips they have billions of transistors in an area smaller than your little nail so you type the numbers they convert into some electrical currents signals they go to the antenna there the current piles up bubbles out into a wave electromagnetic wave which spreads in space with a speed of light it touches millions of cell phones but it's only yours that receives that number magic you never think about engineers they're always in the background you don't know that every working engineer creates seven to ten non-engineering well-paying jobs it is the economy because all the things you see you use go through some simple or extremely sophisticated engineering we say we are the most powerful country in the world what do we mean by that we mean we have the best weapons who makes those it's all engineers what am i trying to say we never worry about our future we're ahead of everyone so did my ancestors what you saw is only one device that we were fortunate enough to find otherwise you would believe what i first heard when i came to this country 1959 as a 17 year old at the university of michigan ancient greeks had philosophy had theater blah blah art architecture no technology no gears how do you respond if you have no proof so that's the proof the other thing they never thought is they were so superior that they would exist forever yet what you see in the roman shipwreck is a standard process of the destruction of the ancient greek civilization which took several centuries and it was obliterated and therefore we had to rediscover all this technology the science the mathematics and so on can it happen to us how do we store our knowledge if what happened to them happens to us it will take at least 10 000 years to recover what we know today think about that so i was very quick technology always defines our ages we start with stone age we got bronze age today it's the information age now i will say very few things and please don't misunderstand me i don't want to insult anyone but i will start a little bit with religion ancient greek religion the way i understand it they believed in one god known an unknown it always has a duality known because of everything they see unknown because of the vastness of the universe and of course they didn't have all the devices who have today to study the cosmos they also believe this is one end it is powerful the most powerful but it cannot only be good because if it's so powerful and only good how does it allow evil to happen earthquakes in nepal for example or people killing one another so therefore that entity is both good and evil then they humanize that entity for all the human faults and goods we see and they have layers of gods in their pantheon and the libyan gods each represents an entity of this one known and unknown so those olympian gods six men six women and there you see a lesbian woman and a homosexual man and also a god of technology hephaestus in greek vulcan in latin technology was praised in the society even though there was no writing it was through poetry and we have homeless poetry until it was written down and in the iliad as well as the you know odyssey you have more than 800 praises exaltations of technology what were the industries let's say from the mythological times we jump to the hellenic period or the classical period the glory of athens and so on we don't have time to go through details or be very quick but had amazing shipping technologies assembly lines to make ships warships commercial ships shipping was the way of communication around the world for them weapon manufacturer mining the mines of lavrio near athens where they got silver and they became a wealthy state to support all these technologies etc i will just spend a little bit on this beautiful temple you know modern scientists engineers mathematicians have spent over 30 years now trying to understand how this was built and i'm not going to spend time on any details other than it will take one column and you see the column the diameter of the column as you go in height diminishes each of the drums or sections fits perfectly you hardly see the line between the different parts but that's not it only inside there is a hole vertical hole inside each drum that matches through down to the ground why was that hole there when the parthenon was reconstructed the first time a german engineer put an iron bar through they assumed that's what they did for stability well after a few years the marble started eroding the ancients were using lead so it preserves them marble but also gives elasticity during earthquakes so they were better engineers now is this technology is it art this is in the museum of delphi what is it look at that this was buried on the ground look at the eyes look at the eyelashes this is bronze what kind of engineering or metallurgy is this isn't amazing look at the eyes different colors actually when you look at it and you turn around it follows you so what did the ancients ancient greeks strive for perfection everything they did the competitiveness amongst themselves was perfection and if you read through their scholarly works you can find a way of explaining that and i derived a simple equation excellence plus harmony excellence is easier than harmony because harmony means not only within yourself but also with other people so that's why perfection is not reachable in reality however if you look at this statue and so many others like the antikythera youth we saw in the beginning it's amazing technology it's amazing art now we lost so much because of all the distractions we would have systematically go through them very quickly and i can answer questions later we didn't know anything about this man where is cyrene well he was mentioned in one of plato's dialogues the title is the thetitus thiertitos was an ancient athenian mathematician was fantastic but there is nothing left of his work other than what we found from others theodorus was a mathematician in cyrene kirini in the called pentapolis the five greek cities did you know that today's benghazi was a greek city called fereniki you don't that's what i mean by everything have been destroyed and buried there you see ancient greek ruins it was one of the first religious uprisings against pagans greeks that destroyed this and romans rebuilt the temple now theodores did amazing work apparently that little that we have been able to understand on studying irrational numbers and he studied them in a way that i can explain later through geometry but look at that this is a book in 1993 by an american professor of mathematics imagine 2 500 years later people are studying the mathematics of the orders so what have we lost these are the continuous equations of the orders i have given this here the spiral of the odors and the spiral of archimedes because i'll come back to the spiral of archimedes later now we got to the hellenistic period very quickly it starts when alexander the great died to 4 15 a.d it's a very critical year because the first woman scientist mathematician was murdered by christian monks chopped up and burned because she was still a pagan ptolemy was one of alexander's generals he took over egypt and brought his body there and buried it and still don't know exactly where but he was amazing in terms of creating an amazing empire eventually the alexandrian empire but also because he created a library and museum of alexandria which i refer to as the first research university in the history of mankind and i spelled here the word museum in the greek way but then how did he do it he invited dmitrios of faliran unknown man who was the governor of athens for ten years he was a student in the aristotelian way of thinking and he is the one who was the intellectual founder of the museum of the lawyer library and this is presumably what he looks like valeron is a suburb of athens by the sea now i will go through this because we don't have time these are full lectures by themselves in the library of alexandria we have the development of amazing science mathematics astronomy technology and medicine i will not touch medicine but the first anatomy was done in alexandria the first examination of the brain was in alexandria the first understanding of the women body was done in alexandria because the first time that human beings started anatomy meaning to touch and open up human beings to understand how we function the deceivers were studying pneumatics and that is the combination of fluid mechanics and air pressure he created an amazing musical organ and who would believe it he was the son of a barber and here's the organ reconstruction where you needed some party to pump air and the musician was playing the valves the musical organ has pumps pistons intake valves inverted cysteins and pressure chambers etc it it had what we have in cars today later on i can read to you an analysis of this by a very famous professor of mechanical engineering and fluid mechanics if we have time later not in this part of the talk here is a proof that this was actually done and this is in the museum in northern greece a musical organ from 150 bc and i hope somebody like michael takes this up to really do a thorough analysis of the mechanical parts and the brilliance of this machine now i had given lectures on this topic more than 10 years ago there were audiences of this size people were encouraging me to write a book but somebody saved me i was beginning to write a book this is a book written by an italian professor of mathematics and philology the forgotten revolution how science was born in 300 bc and white had to be reborn it's an amazing book where he systematically shows the science and technology that disappeared because of religious fanaticism here is another book the archimedes codex i will spend a few minutes with this the authors are reviewing ned is a professor at stanford of archaeology and mathematics the ancient mathematics so what is this this was a prayer book a christian prayer book somebody saw in constantinople today's instabul 1000 ad but he noticed that under the christian prayers there was something else right written in ancient greek that book disappeared from instabul today's name then it was seen in a monastery in lebanon then it disappeared from lebanon then it was found in the possession of a french family who actually sold it in an auction in new york about 16 or so years ago anonymously to an american he bought it he gave it to the museum in baltimore and the funds to analyze it with three-dimensional imaging to see what is written under the christian prayers and under the christian prayers is one of archimedes's original works under a prayer to the dead there is the definition of science exactly the definition we use today and then proving that he was the inventor of integral calculus that he established probability because he was studying how many particles of sand are there in the universe and he was a phenomenal engineer incredible engineer and his mathematics was incredibly sophisticated for the time so we have now modern proofs of these things because when the ancient greek world was destroyed how would people write what they did is they took ancient greek texts which were using vellum animal skin which was invented in pergamum today's bedroom in turkey and they raised the ancient texts and wrote christian prayers if the writing was this way they raised it and they wrote the vertical way fortunately we found this just like the mechanism hopefully we'll find a lot more evidence of the sophistication of that society and remember they never thought that they would be destroyed think about that now first the destruction was when caesar was trying to conquer alexandria to support cleopatra whose brother was actually fighting her they say that part of the library museum or at least the books near the harbor were burned that emperor theodosius ordered everything pagan destroyed libraries were burned temples were destroyed that's why you see statues without arms or noses it was a superiority over the pagans the ancient greeks this is by modern greeks became christian or other christians then emperor justinian closed plato's academy imagine it was functioning for eight centuries also theodosius stopped the olympic games then the arab conquest finished everything off and there is this discussion the general who took over alexandria sent a message to his boss what shall he do with whatever books he found in the libraries and that was the the argument and i always burn them they are useless now there is also an argument between these two authors one is an egyptian and he argues oh this didn't happen yes arab sources are telling us arab i mean muslim sources are telling us that this happened by arabs but these sources are a few centuries later than the event because the italian luciano camphora is arguing that it was not caesar that destroyed the library first because another historian strabo was there two centuries later and was describing the library now this is the first woman scientist mathematician who in the fanaticism of the christian world i don't in some ways you know when i look back it is rome's fault because there's amazing persecution against the early christians you remember that so when christians became large in numbers they ditched it back and it was really vicious anyway she was still preaching teaching the ancient greek way not through christianity she had students who were christians jews as well as pagans imagine it took all these centuries to have another woman scientist in between intelligent women were burnt on the stake imagine that a movie was made in spain a few years ago about her and imagine that the church in spain managed to make sure it is not shown in spain now what was he saying to be killed to know one religion is not to know that one wow superstition consists of one thing faith to one religion to the exclusion of others to know one philosophy is to know none to rule by fettering the mind through fear of punishment in another world is just as base as the use of force because ancient greeks did not believe in hell they believed in the underworld where everybody goes sinners and good people and so on so anyway the bishop of alexandria who essentially ordered her death became a saint i'm showing this to challenge a little bit michael and many others and i will discuss this a little bit more this kind of shape is actually from 20 000 years bc and you see it periodically in various cultures this double spiral and it has to do with the calendar how primitive people were counting months and as a season and a full year well a young engineer by the name xenua yoon derived the equations exactly for the calendar that michael showed us these are archimedean spirals and these are the equations to reproduce those spirals it may have nothing to do with the actual calendar of the mechanism but i thought i'll throw it there for fun i'm done thank you thank you wonderful in the interest of time by the way you've been an incredible audience i i can tell when information is going right in and being received and this has been a very special morning i'm sure the afternoon will be as well michael will be demonstrating the device in the foyer out here we've got about is it an hour for lunch john roughly one hour for lunch stretch your legs see how the machine works grab a bite in the cafeteria and come back here for the afternoon to find out what we're going to learn next about antiquity

Channel: Computer History Museum

Views: 419,825

Rating: 4.6555481 out of 5

Keywords: Antikythera Mechanism, Computer History Museum (Museum)

Id: cSh551cdIEY

Length: 103min 36sec (6216 seconds)

Published: Fri May 22 2015