The Antikythera Mechanism

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Speaker 3 Hello, the Antikythera mechanism is one of the greatest discoveries in the history of marine archaeology, even though, when salvaged in 1901, it seemed like just a lump of corroded bronze.

Speaker 3 It came from a 2,000-year-old wreck discovered by Greek sponge divers, and it was only when this dull lump broke up that its secrets began to be revealed.

Speaker 3 It turned out to be an analog computer of a complexity otherwise lost from the ancient world and not appearing again until the Middle Ages.

Speaker 3 And it challenges our ideas of how advanced the peoples of that era really were.

Speaker 3 With me to discuss the Antikythera mechanism are Mike Edmonds, Emeritus Professor of Astrophysics at Cardiff University, Lieber Taub, Professor Emerita in the Department of History and Philosophy of Science at the University of Cambridge and visiting scholar at the Deutsch Museum, Munich, and Joe Marchant, science journalist and author of Decoding the Heavens on the Antikythera Mechanism.

Speaker 3 Joe Marchant, I've called it an analogue computer. Can you describe what this object was in outline and what it would have looked like?

Speaker 10 It was one of the most sophisticated and complicated objects that we have that survives from the ancient world.

Speaker 10 If you imagine a wooden box about the size of a shoebox filled with bronze gear wheels, so looking like clockwork, little bronze gear wheels with teeth all driving each other around,

Speaker 10 handle on the side to turn it, dials on the the front and the back and it was essentially

Speaker 10 a model of the universe, a little portable cosmos it's been described as. So you had a dial on the front is showing you the movements of the Sun, Moon and planets through the sky, through the year.

Speaker 10 There was a star calendar on there telling you which star constellations are rising and setting at different times and then two more dials on the back.

Speaker 10 There was a calendar, there was information about which athletics games were happening in that particular year, including the Olympics games, and there was an eclipse prediction dial so really it was just a little box you turn the handle to move forwards and backwards in time and it shows you everything about the universe for that particular moment.

Speaker 3 Can you take us back to 1900 when this was lying on the seabed and tell us how it was found and how long it had been lying on the seabed?

Speaker 10 It had been on the seabed for more than 2,000 years, probably dates from the first century BC.

Speaker 10 Yes, it was found on a shipwreck by sponge divers who were on their way from their home in Simi in the eastern Mediterranean to the northern African coast where they were diving for sponges and either on their way there or on the way home they were blown off course by a storm and they took shelter by a little rocky island called Antikythera which is just about halfway between the southern tip of mainland Greece and Crete

Speaker 10 and once the storm had eased the story goes that one of the divers put on the diving suit.

Speaker 10 They were diving in those days in those sort of heavy canvas and rubber suits with a bronze helmet breathing air through a tube that went up to the surface.

Speaker 10 He went down, came back after a few minutes, terrified, saying that he had seen a heap of dead naked women and horses on the seabed.

Speaker 10 And so the captain puts on the suit, they only had one suit between them, goes down and realises that these are not corpses, they are statues, bronze and marble statues from an ancient shipwreck, which those divers then worked with the Greek government to salvage over 10 months from 1900 to 1901.

Speaker 10 And it was an incredible find. It was

Speaker 10 by far the most impressive hall of ancient treasures that had ever been found at that point.

Speaker 10 It was the first ancient shipwreck that was ever salvaged under the direction of archaeologists, so quite historic for the field of marine archaeology.

Speaker 10 And all kinds of things came up: so, the bronze and marble statues, there was furniture, like ornate bronze thrones, bedsteads, there were armour, shields, helmets, gold jewellery, luxury glassware, amphoras.

Speaker 10 So all of these things coming up, being covered in the newspapers all around the world. But everything was being brought back to the National Archaeological Museum in Athens.

Speaker 10 And it wasn't until many months later that an unassuming, corroded lump of bronze broke open and was recognised for being really something rather special that had never been seen before.

Speaker 3 Mike Edmonds, can you take that further and tell us about the route the ship was ship had been following and why it had been following that route? Well, it's the actual route of the ship isn't known.

Speaker 3 It was travelling along what was a common trade route from the eastern Mediterranean towards Italy, really.

Speaker 3 It would have maybe called in at Pergamon and Rhodes, those are possibilities on the way, and be heading towards the Italian ports. It was a well-known trade route.

Speaker 3 It was at one time wondered whether this was a load of plunder that was being taken back towards Rome, but more likely is it was probably some very well-heeled official or something moving his house.

Speaker 3 I mean, how did you move in those days? You couldn't take the train or the road, you had to take the ship. And it's most likely that this was some rich person moving with all their stuff.

Speaker 3 Why would that stuff include the mechanism we're going to talk about? Well, that's an interesting question. Presumably, because it was a high-status object that somebody might like to own.

Speaker 3 We'll no doubt have to talk quite a lot about what the thing actually was for, because nobody's actually entirely clear what it was for.

Speaker 3 But one good possibility, it was a statement about what the Greeks knew at this time about the universe.

Speaker 3 And somebody had no doubt seen a market opportunity and realized that a lot of people, you know, in the upper echelons might like to appear at least to be interested in such things and to have such a thing on their mantelpiece as a talking point and show that they were interested in the universe.

Speaker 3 I mean, there was to some extent, I believe it's a Pythagorean or Platonic view that if you actually take an interest in things celestial and so on, you almost become a bit immortal yourself.

Speaker 3 So it being a nice object that somebody could have had on their mantelpiece and might have been prepared to pay for, too.

Speaker 3 Who were the first curators to get to grips with it, it having been discovered? The bronze has undergone chemical changes, it's very fragile and so on.

Speaker 3 Any wood in it has now virtually rotted away, obviously. But there's still enough there.

Speaker 3 And what's amazing about it, too, the bronze plates with which it was made are covered in inscriptions in Greek as well.

Speaker 3 So it comes not with a user manual, but at least a user specification, as it were, with it, which has been enormously helpful in beginning to understand what it did.

Speaker 3 But the story of how it came to be, we talked about how it began to be discovered. And what happened was interesting, there's a guy called Spiridon Steis,

Speaker 3 who was the Minister of Education in Greece, and he'd been quite

Speaker 3 instrumental in getting the underwater archaeology going.

Speaker 3 And anyway, he came, by this time, he wasn't Minister of Education anymore, like modern-day ministers, they don't last long. And he was MP, basically, for Kithra.

Speaker 3 And he was visiting the museum, National Archaeology Museum, and he went down the basement where they'd got all this stuff. And he said, what's that?

Speaker 3 Pointing at this bronze thing and saying, well,

Speaker 3 everybody sort of looked a bit surprised because it's a bit of bronze, you know. But it had cracked open.
It presumably had dried out. And you could see in it the outline of gear wheels.

Speaker 3 And that was the real teller.

Speaker 3 Precision gear wheels, metal gear wheels, aren't known from the classical world. Here's the first example of them.
And also the beginnings of these

Speaker 3 a few words of Greek that they could see were related to astronomical things. That's what when it really started the study of it.
And over the years, it was

Speaker 3 gradually sort of split apart a bit more to see what was inside it.

Speaker 3 And it's only in the 1960s and onwards, once you get into radiology and so on that the real complexity and beauty of this device began to be realized. It's extraordinary isn't it? It is.

Speaker 3 Lieber, at the time the ship went down, what was the understanding at that time of the moon and the planets and their movements?

Speaker 5 We're very fortunate that we have a book by someone called Geminus.

Speaker 5 who was working in the first century before our era, so the same century in which the shipwreck occurred.

Speaker 5 The book is called The Introduction to the Phenomena, and it is an introduction to astronomical observation and to astronomy, and it gives us a very good impression of what was being taught in the period.

Speaker 5 It's very likely that Geminus himself was not a researching astronomer, but was rather an educator and possibly even a popularizer.

Speaker 5 We know that he wrote another work talking about different kinds of mathematics, and astronomy was, in the period, period considered to be a branch of mathematics.

Speaker 5 The title of the book was Introduction to the Phenomena and Phenomena here means what we can see. It means the appearances.
So he's focusing on what can be seen in the sky.

Speaker 5 There are the so-called fixed stars, which are constellations or asterisms, which seem to keep their relative positions as they move through the sky.

Speaker 5 There are also the so-called planets or wanderers, the Sun, the Moon, and the five that we consider to be planets, Mercury, Venus, Mars, Jupiter, and Saturn.

Speaker 5 The phenomena that I've mentioned, the observations that people could see just looking at the night sky, in some ways seemed to be regular, that, for instance, the rising in the east and the setting in the west.

Speaker 5 But people noticed that the planets, the wanderers, seemed to drift.

Speaker 5 And the big challenge, or one of the big challenges of Greek astronomy, was to give an account of how the planets seem to move, appear to move, in non-regular ways.

Speaker 3 How widely was this kind of knowledge shared and who took an interest in it? It isn't the first thing we think about when we think about the Greeks and so on.

Speaker 5 Well, I think that the way that Geminus' book is set out, that it is an introduction to the phenomena, to astronomical phenomena, gives us an impression and an indication that you didn't need to be a specialist.

Speaker 5 You didn't need to be a mathematician, an astronomer to be interested in these phenomena. The book seems to be educational.
It's possibly even a textbook.

Speaker 5 It doesn't seem at all as if it's being written only for specialists.

Speaker 3 It didn't come turn to you now, Joe Martin.

Speaker 3 In the 1950s, Derek DeSola Price took an interest in the mechanism. What did he find out?

Speaker 10 Yeah, Derek Price Price is a really interesting person. So there were several scholars before the Second World War who had taken an interest, had some different ideas.

Speaker 10 Was it an astrolabe or a planetarium?

Speaker 10 Sort of reading traces of inscriptions there was an idea that it was something astronomical, although there was also an idea that perhaps this was a hoax because it just seemed so incredible that something so sophisticated would have come.

Speaker 10 But Derek Price, he was interested in the history of science.

Speaker 10 So he was a physics professor originally born in East London, but went to Yale to become the first professor of the history of science in the US.

Speaker 10 And he was interested in the history of knowledge and particularly the history of ancient scientific instruments, especially astronomical instruments.

Speaker 10 He thought that through the devices and the instruments they held the sort of secret of the history, the progression of human knowledge.

Speaker 10 So in the 1950s, he started studying the pieces of the Antikythera mechanism in the Athens Museum, worked with an epigrapher to decipher more of the inscriptions, came up with this model of the wooden shoebox with the two faces, the dials on the front and the back, realised that the front dial was showing the sun and the moon.

Speaker 10 And then in the 1970s, he worked with a radiographer. And he was really the first person.
He didn't know how it worked or quite what was going on, but he knew it was important.

Speaker 10 He said it was as spectacular as if the opening of Tutankhamun's tomb had revealed the remains of an internal combustion engine. Like he was the person who said, this matters, this changes everything.

Speaker 10 This is the the roots of our modern technology right here in ancient Greece.

Speaker 10 But he didn't really get much further with it until the 1970s when he worked with a radiographer in Athens and was the first to x-ray the pieces.

Speaker 10 So now you're seeing the gear wheels that were hidden inside.

Speaker 10 And in particular, he was counting the teeth on all of those different sized wheels because the gears are driving each other around with the teeth.

Speaker 10 And the differences in speed depend on the number of teeth with the different wheels. So you're carrying out mathematical calculations with these wheels.

Speaker 10 You're converting one speed into another speed. In particular he looked at the

Speaker 10 train of six gear wheels.

Speaker 10 So you turn the knob on the side, the first six gear wheels, and he realized that they convert the speed by a ratio of 254 over 19, which might not sound particularly impressive, but he realized that these were numbers that were found in a Greek calendar that harmonizes the motion of the sun and the moon.

Speaker 10 It was essentially converting the speed of the sun into the speed of the moon through the sky.

Speaker 3 You wanted to come in? Yeah, well, I mean, just think of yourself.

Speaker 3 You're a Greek, and you look at this device. You're asking, well, what's the relevance?

Speaker 3 How are the Reef's going to react to this? But there you are, there's the heavens in front of you. There, you can see the moon changing its phase.
You can see the Sun going around the sky.

Speaker 3 And presumably, too, the planets as well, though that part of the mechanism is unfortunately lost. We certainly believe that it was there.

Speaker 3 And so, in a way, here's a device that allows you to visualize the heavens in a different way and realize that you don't have to have gods pushing the planets around.

Speaker 3 It's an interesting philosopher's viewpoint that that's what was doing. But maybe, look, here you can do it by gear wheels and things.

Speaker 3 And surely that leads you on to great philosophical speculations about what the universe is really like. Nobody's going to say it's got big gear wheels that drive everything round.

Speaker 3 But the point is, something is doing it, and it doesn't have to be gods anymore. There's also, the ancients knew that the movement of the planets wasn't regular.
How did the discovery made

Speaker 3 tackle that?

Speaker 3 Well, this is interesting. As I say, unfortunately, the actual mechanism that would show the planetary motions is missing from what's left of the mechanism.

Speaker 3 But we know from the detailed inscriptions on the device that it probably did display planetary positions.

Speaker 3 We might worry, how would they have done this because it was quite you know technically not trivial to show the retrograde motion of the planets and things going forwards and backwards with gear trains.

Speaker 3 But we know from the way they designed the lunar train, the one that's there, that shows how the moon moves in the sky, that they were clever enough to be able to incorporate non-regular motion in that.

Speaker 3 It has irregular or regular irregular motion, if you like, a Rumsfeld type description. In other words, they knew how to devise gear trains.

Speaker 3 And in fact, they're very sophisticated, interlaced gear trains that give you this variation in the lunar speed and its orbit.

Speaker 3 And that shows that if they'd wanted to, and we believe they did want to, they could have done that for the planets too.

Speaker 3 Thank you. Leva, who would have had the skill to make something like this? Do you have any idea?

Speaker 5 I believe it's very likely that more than one person was involved in creating this object. And as you've already pointed out, there's lots of things that are in this object.

Speaker 5 It's not one type of information that's being portrayed and depicted. There's also the calculating function, etc.

Speaker 5 So someone would have had to know about astronomy. Someone would have had to know about calendars.

Speaker 5 The games have already been mentioned, so people would have had to know about the different games that are depicted on there and their calendars.

Speaker 5 Someone would have had to have the skill to do the metalwork and the the gearing, and it may well have been that person doing the gearing may very well have been a different person from the person who did the inscribing, the engraving on the object.

Speaker 5 So I think it probably makes sense to think of the object as a product of collaboration, possibly even what we might think of as a workshop.

Speaker 3 So they're making an image of a universe mechanically.

Speaker 5 That's part of what's going on here, yes.

Speaker 3 What's the other part?

Speaker 5 Well, for instance, the part with the games dial, for instance, which is very interesting because it has nothing to do with astronomy here. So it's not only an astronomical object.

Speaker 10 I think what's interesting actually is that it shows us that for the Greeks, they didn't make that same separation between earth and sky that we do.

Speaker 10 So we would think, oh, well, it's showing astronomy, so why are the Olympic Games in there?

Speaker 10 But they would have had a much more holistic view where what was going on in the heavens was really sort of mirroring, driving,

Speaker 10 guiding, informing what was going on on earth and they also wouldn't have had the same distinction that we have between astronomy, the scientific observations and astrology.

Speaker 10 So we see all of these things mixed together and I think that that makes sense as this device really being a holistic model of the workings of the universe as they understood it at the time.

Speaker 3 Another reason why there might be Olympic or this game style there is because calendars varied all around the classical world. Almost every city had its own calendar.

Speaker 3 And so if you're using this device you might wonder whether you've got the set the all year right for your particular calendar.

Speaker 3 But everybody would know whether the Olympic Games were happening that year or a couple of years time.

Speaker 3 So it may have just been a way of orienting as to where you were when you were playing with the device. It's possible.

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Speaker 3 Jared, back to you for

Speaker 3 there any particular philosopher at the time? There were plenty of them. Were there any one or two who underpinned what was going on?

Speaker 10 Well, one philosopher whose name often comes up relating to the Antikythera mechanism is Posidonius, who was working in the first century BC on the island of Rhodes.

Speaker 10 He was a Stoic philosopher who would have seen the universe as guided by this sort of holistic divine force, not so much different gods in the heavens as you might have seen previously with the babylonians for example and the reason that his name comes up is because cicero who had written accounts of descriptions of of this kind of machine at one point says our friend posidonius made this bronze machine that models the motions of the sun moon and planets in the sky and cicero visited rhodes in the first century bc when posidonius was working there at just about the same time as the antikythera ship would have stopped there so all of these these strands are kind of coming together.

Speaker 3 And the name Archimedes comes up. Is he relevant to what you were talking about?

Speaker 10 Yes, Archimedes always comes up with any ancient invention.

Speaker 10 But yes, because Cicero wrote another description of a very similar sounding device and in this case he says that it was built by Archimedes.

Speaker 10 Now Archimedes was working a couple of centuries earlier, 3rd century BC, all the way west in Syracuse in Sicily.

Speaker 10 So he was working too early to have made this particular device and in the wrong place for where we know that a ship would have sailed.

Speaker 10 But it is possible that he could have invented this tradition of devices, this idea of modelling the motions of the heavens in bronze.

Speaker 10 And perhaps he would have made a much simpler version, perhaps just the different speeds of the Sun, Moon and planets without all of the speeding up and slowing down and changing direction that we know the Antikythera mechanism did.

Speaker 10 And you can imagine that over the generations, these models would have become more sophisticated

Speaker 10 folding in the latest astronomical advances as they as they occurred and then the third name that I wanted to very quickly mention is Hipparchus an astronomer who was working on Rhodes in the second century BC just a few decades before Posidonius because he was working on these epicyclic theories that have been mentioned he modelled he had a sort of a mathematical theory for the change in speed of the moon that we see in the Antikythera mechanism so it could have been his his astronomical theories then feeding into those mechanical designs and perhaps Posidonius and his workshop were then building on that in the first century BC.

Speaker 3 Thank you very much. Mike,

Speaker 3 what is feeding off what in this?

Speaker 3 Are the makers of this instrument or instruments, let's use the one that we're talking about, influenced by what they see?

Speaker 3 Or is it the other way around?

Speaker 3 A bit of both, I suspect. It feeds probably both ways.
I mean, I agree with what Joe was saying.

Speaker 3 A most likely thing is some sort of small workshop could have produced these, and maybe there are workshops elsewhere.

Speaker 3 You mentioned Archimedes, he wrote a book apparently about such devices, probably called Despheri.

Speaker 3 But it's been lost. You don't have a copy, do you? I'm afraid.
But if only we could find the copy of that book, we'd know how far advanced they were at Archimedes' time. But it's been lost.

Speaker 3 Perhaps it'll turn up in Panamsest or something one day.

Speaker 3 But I'm sure that there must have been a two-way trade between building these devices and developing the theories that went with them.

Speaker 3 I mean, circles, rolling on circles, classic Greek mathematics, how many circles you can fit together and so on.

Speaker 3 And I suspect, and some of the philosophers nowadays do think so too, that it was a two-way process.

Speaker 3 You look at these devices, they're built, these devices, it gives you new ideas about the planetary theory. So I suspect those things coexisted for a while in developing planetary theory.

Speaker 3 Libra, who might have commissioned this particular object?

Speaker 5 Well, I tend to agree with Mike that this is probably someone, well, certainly someone who had the money to commission it, to pay for it, and someone probably who also wanted to show off his interest in astronomy, that he was an educated person, that this was the sort of thing that he knew about.

Speaker 5 I think the person was probably Greek. I think it was probably a man.
And if he wasn't Greek, he may have been a Roman who was wishing to show off Greek knowledge.

Speaker 5 It certainly was a very impressive object. And as it's already come up, it does all sorts of different things.
And I think that's one of the most interesting questions is what was it for?

Speaker 3 And I think

Speaker 5 what it was for may have been to show off knowledge, to show off sophistication, possibly to even show off money. And Mike suggested that someone wanted to put it as a status symbol on a mantelpiece.

Speaker 5 I think it's possible that someone wanted to bring it to their dinner table, to the sort of dinner party and drinking party that we call the symposium.

Speaker 5 And we know that at symposia, men would get together and have learned conversations. They might have some body conversations as well.

Speaker 5 And there'd be all sorts of entertainment, including intellectual entertainment.

Speaker 5 We also know from writers like Vitruvius writing in the first century before our era, the same period in which the object went down into the sea.

Speaker 5 We know that there were objects that were devised purely for amusement. He describes some of these in some detail.

Speaker 5 One of the people that he mentions, an earlier person, Catsibius, who had made such some objects that were purely for amusement, some of them also had gears.

Speaker 5 So we have all kinds of examples of fancy objects, for instance, depicting birds singing that used water pressure to operate.

Speaker 5 We also have trick drinking cups that are not mechanical particularly, but amusing. We also have later authors like Hero of Alexandria describing such things.

Speaker 5 And I think it's entirely possible that this was a very elaborate, very fancy object. We don't know, you know, as Mike has said, some of the bits are missing.

Speaker 5 It may have had some decorative bits as well. So I think that one of its functions was to impress people, but also it could have been literally a conversation piece at a dinner party.

Speaker 10 So I agree that it was part of what it was about was wealth, status, wonder, entertainment.

Speaker 10 But I do think that there was a much deeper philosophical purpose here, that it was absolutely about understanding and exploring the the nature of cosmos, reality,

Speaker 10 our relationship with that universe.

Speaker 10 One of Cicero's writings, he said if somebody looked, if somebody in a barbaric land like Britain saw one of these things, they would know it was made by a rational creator.

Speaker 10 So it was really an expression of this rational design, order, purpose in the universe. But at the same time, it's an expression of the idea,

Speaker 10 it's moving from this previous idea of the universe as this sort of chaotic, quite magical place with the celestial bodies as gods kind of warring in the heavens to

Speaker 10 a single mathematical system where everything is connected, everything

Speaker 10 has order, where everything works according to mechanical physical rules, not bronze cogs, but rules that we can investigate, understand, predict.

Speaker 10 And so the technology of the Antikyther mechanism is really important, but that idea is also so important because that, for me, is really the birth of that scientific world view of seeing reality as a mechanism that we can study and understand.

Speaker 3 Yeah, Galen, you may know as the medic, the famous medic, who's a few hundred, a couple of hundred years later, really at the time. But he knew about such devices.

Speaker 3 We've evidence from the literature that they certainly lasted until about 500 AD. They were still around by 500 AD.

Speaker 3 And Galen says, look, I'm not sure that our bodies work in quite the same way as your planetary mechanisms do. And it's discussed as to whether, you know, how mechanical the bodies are, and so on.

Speaker 5 I think it's also possible that this was a demonstration device showing different astronomical explanations and motions as well.

Speaker 5 So when I say entertainment or meant to be impressive, I think it may have had a somewhat intellectual and educational, in a broad sense, function as well.

Speaker 5 And we can even, in some ways, imagine a copy of Geminis' book being available and this object being alongside it.

Speaker 5 And maybe if you're hosting a symposium, you might want to give a little demonstration lecture about astronomy.

Speaker 3 Joe, after Derek Price, what were the main leaps in the understanding of the mechanism after him?

Speaker 10 Well, in the 1980s, there was a young curator at the Science Museum, young at the time, Michael Wright, who became interested in the antikythera mechanism.

Speaker 10 And he worked with a historian of computing who was based in Australia called Alan Bromley. They went to Athens and re-x-rayed the pieces.

Speaker 10 This time Wright built a kind of cradle, a tomography cradle for swinging the x-ray film and the object relative to the source, the x-ray source.

Speaker 10 And it allows you to just bring out into focus different planes of the picture. In a normal x-ray, it's just everything is sort of smushed into one level.

Speaker 10 So by doing tomography, they could really pick out the 3D arrangement of the gears. And Michael Wright then studied those, and he makes things.
He makes mechanisms. So he built what he saw.

Speaker 10 And he was the first person to suggest that this mechanism was modelling the planets. He saw traces of what he thought were

Speaker 10 something carried around on that big wheel, so little wheels being carried around on the big wheel, suggesting epicyclic gearing, that this is how it was modelling that looping motion of the planets.

Speaker 10 He realized that the dials on the back, everybody thought they were concentric circles, but he realized they were actually spiral dials, spiral grooves, with a little extendable pointer with a needle tracking that spiral groove just like a record player, which is one of my favourite details about the mechanism.

Speaker 10 And then around 2004, there was an international collaboration led by Mike as the academic lead and also Tony Friefer, mathematician and filmmaker from London.

Speaker 10 And they brought together expertise, academics from different countries, and state-of-the-art technology.

Speaker 10 There was very high resolution, powerful CT scanning, so producing these three-dimensional X-ray images of the insides of the fragments to very, very fine resolution, and also using some technology from Hewlett-Packard that was originally developed for computer graphics to image the inscriptions.

Speaker 10 And that really led to increasing detail and realizing the final piece of the mechanism, which was the one of the back dials was actually predicting eclipses, which hadn't been realized until that point.

Speaker 3 Mike, can I come back to you? Does this fit in with an idea of three movements of thought going on? One was Israel. The Christian movement had developed, obviously.
One God.

Speaker 3 And before that, there were many gods. And now there was mechanical.

Speaker 3 Yeah, all mixed in there. All mixed in.
I think you get the many gods first.

Speaker 3 This is coming at the time of many gods, but then towards the end of the period, I was saying about 500 AD, when these things seem to die out, that's when the Christian era is really coming in.

Speaker 3 And you do wonder whether that may be something to do with why you don't see them anymore. There may have been a progression through that.
But there are other aspects of this which I rather like.

Speaker 3 I'll just mention, for example, I think there are things within the mechanism that show a much deeper continuity of thought.

Speaker 3 Now, these are people, you know, I make myself very unpopular with my colleagues saying these things, but for example, there's a big wheel in this thing. It's the classic thing.

Speaker 3 You look at the pictures, and this is a big chariot wheel, it looks like, in the mechanism. And that's the main wheel that turns once a year

Speaker 3 when you're playing with the mechanism. That represents one-year turn

Speaker 3 now chariots and chariot wheels are associated with the sun and in in mythology and in artwork and so on and indeed that wheel has let me get it right 233 teeth the

Speaker 3 seros cycle of months basically so of lunar months between eclipses there are bits in this mechanism that are emblematic of the way you talk about astronomy the the way you talk about the heavens, and have always done so, going back maybe thousands of years.

Speaker 3 It's not just a sudden mechanical device. It comes very much in a tradition of thinking about the sky.

Speaker 3 Are these decisions disputed between those holding them? I think the point is, it shows that it was a great time for intellectual discussion.

Speaker 3 For example, I mean, this device is geocentric. It's based on Earth and what you see from Earth and whatever.

Speaker 3 But we know that they discussed in Greek times whether it was a heliocentric universe or not. You know, everything going around the Sun rather than around the Earth.

Speaker 10 Everyone thought that was a crazy idea.

Speaker 3 Well, not everybody. Not everybody.

Speaker 3 But, you know, what gets suppressed, what doesn't get suppressed, all these ideas are in a melting pot. And of course, it's a time of great political change as well.
So

Speaker 3 it's the sort of atmosphere in which you would get the sort of discussions about what is the nature of the universe and so on. Liba, who would have been writing about this at the time?

Speaker 5 Well, as I mentioned, Geminus himself talks about astronomical instruments, and this includes teaching devices. He mentions a sighting instrument known as the dioptera.

Speaker 5 He describes armillary spheres, which are composed of rings and which would normally show, for instance, the ecliptic, the path of the sun, and the zodiac. He also describes celestial solid globes.

Speaker 5 I've mentioned Vitruvius as well, and he described different sorts of instruments and objects, including some with teeth.

Speaker 5 He mentions Casebius, who he says wrote about such objects, but we don't have his writings, sadly.

Speaker 5 We do have later writings, and as Mike and Joe have both mentioned, we have different writers, including Cicero, who's not particularly a scientific author, talking about different models of the heavens.

Speaker 5 So and Galen also, as Mike mentioned, and Ptolemy, much, you know, later, who was a contemporary with Galen, but in the period that we're speaking about, the first century before our era, I think that Vitruvius is particularly interesting, and Geminus as well.

Speaker 5 And they clearly had some knowledge of objects that were in some ways related, possibly simpler versions of the mechanism, but no one describes anything, even Cicero, I don't think, that truly fits the description of the mechanism with all of its different capabilities and, of course, with its gear work.

Speaker 3 Indeed, I think that's what we wish we had more literature on some drawings from this era. We don't.
We have to rely on what we've got.

Speaker 3 And I think it's true if we didn't have the anti-kytheroic mechanism, we'd never have perhaps imagined that it could have been as complicated as we find it.

Speaker 3 And what would have been the consequence of that?

Speaker 3 That we lost something in our admiration for the Greeks, I guess.

Speaker 3 I mean, it's true that if you look at the jewellery of the time, there's no difficulty in imagining the Greeks could make the hand, you know, the actual metal work can be done.

Speaker 3 They're really good at doing jewellery and so on. They can do the metal work of this.

Speaker 3 But what I don't think we had any idea of, unless until you've got the Antikythera mechanism in your hand, is realizing that they can do sophisticated engineering design.

Speaker 3 Okay, they've done some of these things Lieber was talking about, particularly in theatres,

Speaker 3 birds,

Speaker 3 opening doors that open automatically, and so on. But the idea of a precision gearing and thinking that out is something we would have no idea about.

Speaker 3 And I think it's interesting in the 1960s and 70s, when de Solar Price was writing, to some extent, people just ignored the Solar Price because they thought, this can't be right.

Speaker 3 The Greeks couldn't have been that clever.

Speaker 3 And it was just a sort of being a bit, I don't know, a bit arrogant, I suppose, for the for our scientific era if you go back to 1800 and look at uh encyclopedias that were written and there's an edinburgh encyclopedia was written in 1800 talks about the possibility of various planet planetary mechanisms and uh orrearies and so on and there

Speaker 3 talks about that the Greeks had them and that comes from the literature references not because they had the anti-Kytheromechism because they didn't have it then they had descriptions in the in the Greek literature implying such a mechanism and they had no trouble at all with that because it was the era of the great classical education no doubt and they were used to the Greeks and Romans being as clever as we are but I think we forgot that during the 1960s and 70s to some extent and this has in a way brought us back to realize that you know they're just as intelligent as us and a fascinating civilization.

Speaker 10 Well if we didn't have the Antikythera mechanism I think we wouldn't we wouldn't realize that some of the technology that has absolutely shaped the modern world.

Speaker 10 So mechanical gearing has been so important in the development of clocks and timekeeping, which was very important then economically as well, but also the automated machinery that drove the Industrial Revolution is all reliant on these sophisticated gearing techniques, wheels riding around on other wheels.

Speaker 10 And this is showing us that those technologies, which have often been credited to the Europeans, we tend to credit everything to ourselves, that the beginnings of that technology actually go all the way back to ancient Greece.

Speaker 10 And when you know what clues to look for, you can actually see hints of it in the Byzantine Empire and in the Islamic world we know of a sundial from the 6th century Byzantine Empire so inscriptions in Greek but it's got a little geared calendar eight gear wheels showing the movements of the Sun and the moon and then from the Islamic world there's a manuscript in Arabic a 12th century copy of a 10th century manuscript which has exactly the same, a drawing of the sundial with the eight gear calendar and then an actual astrolabe from 13th century from Isfahan, Iran, again with this eight gear wheel calendar.

Speaker 10 So when you know what to look for, this is much simpler than the Antikythera mechanism, but you can see that that tradition of modelling the heavens with gear wheels survived through the Byzantine Empire, the Islamic world, and then came back to Europe, possibly through Spain in the 12th and 13th century, and then helped to trigger the invention of modern clocks.

Speaker 10 Because clocks, the beginning of clocks is very strange, because all of a sudden, they don't start simple and slow and get more complicated.

Speaker 10 All of a sudden at the very end of the 13th century, beginning of the 14th, you see an explosion of sophisticated, complicated astronomical clocks all over Europe and they are showing the sun, moon, planets, they're predicting eclipses.

Speaker 10 So it seems as if that technology was sort of waiting in the wings for somebody to invent the escapement, that sort of ticking bit that regulates

Speaker 10 the weights into an even progression. And then that got added to these geared mechanisms and suddenly you've got these complicated astronomical clocks almost coming as if out of nowhere.

Speaker 10 And I don't think we would have necessarily realised that progression without knowing that the antikythera mechanism stands at the beginning of all of it.

Speaker 3 The problem is, and I think it still remains a big intellectual problem, as to whether that's a continuous process.

Speaker 3 In other words, the knowledge to have how to really do it survived into the beginning of the era of the clocks, or whether it was independently rediscovered, the possibilities of gearing at that time.

Speaker 3 What is interesting though is that certainly later astronomers, for example, Kepler, knew that the Greeks had made these sort of model mechanisms.

Speaker 3 In his letters he talks about doing his own mechanism to show planets and things and refers to the fact that the Greeks had done it before.

Speaker 3 But as you say, tremendously important in later times, times and would prompt, I'm sure, you to think, well, what if the Romans had developed this in more detail? Why didn't they?

Speaker 3 Why didn't they develop this geared technology? They were wonderful at building aqueducts, civil engineering, and so on. Why didn't they seize on this?

Speaker 3 Think of the things they could have built with it.

Speaker 10 I suppose they saw it as a philosophical device more than a sort of practical working thing. I mean, I was just speculating, but I think maybe it sort of shows us the sort of

Speaker 10 the category of device that it was perhaps in that the Romans.

Speaker 3 And obvious ones you might try and do, say, well, let's make a simple calculator, you know, just to do tens and, you you know, add up the number of wheat sheaves in the field or whatever, or do the land calculations.

Speaker 3 But they had slaves to do that, and use abacuses and things, and they didn't need it. So maybe it was only later that the need for such technology to be developed, developed.

Speaker 3 Liba, I'm coming to the end now.

Speaker 3 What are the unanswered questions about this?

Speaker 5 Well, Melvin, I think that many of the questions that you've already posed to us are questions that we still need answers for, that we still are looking for answers.

Speaker 5 And I think one of the things that's very interesting is that we, due to modern technology and things that have happened over the last 50 years, we know quite a bit about the object itself, how it worked, the different parts of it, etc.

Speaker 5 But we don't really know that much about the human side of it.

Speaker 5 So we can speculate, as we've done today, about who made it, we can speculate about who commissioned it and why, but we don't really have those answers.

Speaker 5 And as I think we've all said, we're missing things that existed in the past.

Speaker 5 There are certain writings, there are certain objects that we have descriptions of, but we don't have the actual things anymore. We don't have these books, we don't have the objects.

Speaker 5 So I think that probably the three of us are hoping that some more things are going to be discovered and that more work will be able to be done to give us more information

Speaker 5 about who made it, who commissioned it, and why.

Speaker 3 At which Mike Edmonds put two thumbs in the air. What I hope for is maybe something like Herculaneum, Pompeii.
Perhaps they'll find a rich merchant's house and excavate and find one.

Speaker 3 And that would be very exciting. Well, thank you very much.
Thanks to Libra Tob, Joe Marchant, and Mike Edmonds.

Speaker 3 Next week, the 20th century Italian author of Invisible Cities and If on a Winter's Night a Traveller, that's Italo Calvino. Thank you for listening.

Speaker 15 And the In Our Time podcast gets some extra time now with a few minutes of bonus material from Melvin and his guests.

Speaker 5 Well, one of the things that I would have liked to have said, jumped in when the point was made about technology.

Speaker 5 And I think one of, and it was Mike who said that when Derek Price did his work, people really weren't that focused on it.

Speaker 5 And Gears from the Greek was the title, and it just seemed people didn't really know what to make of it.

Speaker 5 And I think part of it is that there's been a long-running idea that the Greeks weren't very interested in practical things, that they did some very high-faluting mathematics, they did some very high-faluting astronomy, but it was the Romans who were interested, for instance, in engineering, and that's a word that Mike used.

Speaker 5 And I think one of the things that is very interesting about the mechanism is it does show that some very, very sophisticated engineering was being done by Greeks.

Speaker 5 So it really gives us a different view of the culture, and it would be wonderful to have more examples of this.

Speaker 3 Mike, what would you like to have said that there wasn't time to say?

Speaker 3 Only, I still enjoy the fact that

Speaker 3 there are clues in this mechanism to an older tradition in astronomy, in my view. I mentioned this chariot wheel on the front, which is associated with the sort of sun moving across the sky.

Speaker 3 Greeks had that view of of a chariot carrying the sun across the sky, but it's much older. It goes back, there are sun chariots from Scandinavia, at least a thousand years before.

Speaker 3 It may even go back to Mycenaean Greece. The cast sign of linear B, which may well be a pictorial for a sun, is the same shape as the main wheel in the Antikythera mechanism.

Speaker 3 And I think it just shows that this isn't the... It's not...

Speaker 3 I don't know if you'd call that, you know, sort of a religious thing. It's not a religious thing at all.

Speaker 3 It's just how you design something, what you're comfortable with, what the tradition is when you're building an instrument or talking about astronomy or something.

Speaker 3 I think there are clues in the mechanism for that. I just find that very comforting and rather nice, rather than just all the abstract mathematics as well.
It's a human thing that

Speaker 3 you're telling the story of the universe, but the clues you've been using before and the ideas you've been using before are there as well.

Speaker 10 I would like to have a go at explaining one of my favourite features inside the mechanism, just to give a sense of the sophistication and how it was actually working inside the box.

Speaker 10 And this is the part of the mechanism that models the very slight variation in speed of the moon in the sky. So the moon's orbit is elliptical, not circular.

Speaker 10 So as we look at it, it's speeding up and slowing down. The Greeks didn't know about the elliptical orbit, but they knew about the variation in speed.

Speaker 10 And what happens inside the mechanism is you've got four little wheels, two pairs, two above the other, and one of the bottom ones has a little pin sticking up and it drives the one above it.

Speaker 10 The pin goes into a little slot and because the centres of the wheels are very slightly offset, the pin moves backwards and forwards in the slot and that introduces this little wobble in the speed of the one above and that's where the wobble comes from.

Speaker 10 But it's not just that.

Speaker 10 Those four wheels are in turn mounted on another bigger wheel that is going around once every nine years because that wobble in the moon's motion in the sky is actually moving around the sky once every nine years.

Speaker 10 So that whole mechanism is sitting on this bigger wheel once every nine years to model that very subtle motion. And not even just that, because that

Speaker 10 wheel that it's riding around on is actually the wheel that's driving the eclipse dial that has to move at a different speed.

Speaker 10 So there's a couple of extra wheels that slow it down so it's just right for the moon pointer and then speed it up again later so that you can then drive the eclipse dial.

Speaker 10 So it's they're being very economical. They're reusing wheels inside the mechanism.
So I just think that that's absolutely breathtakingly clever and sophisticated.

Speaker 10 And just to give an idea of how all of this was working inside.

Speaker 3 And this is what we're saying about design ability, engineering design ability. They had no idea that the Greeks could do that.
That's the surprising thing.

Speaker 10 And it shows us that this can't have been the only one, because you couldn't make this as your first mechanism. It was too sophisticated, too confident, too small.

Speaker 10 It had to have been the product of generations of work of building on this idea to get to something like the Antikythera mechanism.

Speaker 3 And my guess would be that these date from probably, I don't know, certainly 200 BC, maybe a bit earlier, right up to 500 AD. It can be traced back

Speaker 3 to some design elements. I'll just call them design elements.
For example, I say this chariot wheel is something that I think has an image of the sun.

Speaker 3 And if you're doing something concerned with the sun, it's the sort of trademark, if you like, of the sun that you would use. And I think that's what's in the mechanism itself.

Speaker 3 But there are other things.

Speaker 3 the form of these calendrical dials of spirals makes me wonder. And I wish maybe we just don't know enough about this.
I suspect a spiral was a way, typical way of representing a calendar.

Speaker 3 Maybe it's a bit fanciful, but the Newgrange site, which is a sort of megalithic site in Ireland, solstitially aligned, and that has spirals on.

Speaker 3 It's a very common device on megalithic or megalithic-type observatory or pseudo-observatory constructions.

Speaker 3 And I just wonder if the idea for a spiral was such that that's what you might, if you were doing a design of a calendar, you would put it on as a spiral just because that's what you thought was the right sort of shape for it to be.

Speaker 3 And I wonder if there are other things in the device, if we look carefully, that they do just fall in this idea that there's a continuity there that we're perhaps missing.

Speaker 3 Because unfortunately, it'd be nice if this thing had beautiful design on it and lovely

Speaker 3 gemstones and everything. It doesn't, but

Speaker 3 there are design elements there that I think do date from before this time.

Speaker 10 Well one thing we should really have mentioned is the influence of the Babylonians.

Speaker 10 So the Greek astronomy generally was very influenced by Babylonian astronomy and Hipparchus who we think sort of may well have played a role in leading up to the Antikythera mechanism he was very interested in Babylonian astronomy.

Speaker 10 It's been suggested that he travelled to to Babylon and was getting information from the astronomers' tablets there because the Babylonians over centuries were making very careful observations of the sky because they believed that they could see omens in the sky that were important for foretelling the future.

Speaker 10 And they were very accurate and they came up with very sophisticated arithmetic algorithms for predicting motions in the sky.

Speaker 10 The Greeks, by contrast, had this very geometric sort of three-dimensional view.

Speaker 10 Hipparchus was really the one who brought those two traditions together, who said, we can't just talk about all these circles in the sky. We need to know the numbers.
We need to be measuring.

Speaker 10 We need to be observing what's actually happening.

Speaker 10 And we do see Babylonian influences in the Antikythera mechanism, in the eclipse prediction dial, for example, the timings of the cycles used for the eclipses.

Speaker 10 So, it's important to think about this not just as a purely Greek thing, but you can absolutely see those influences coming from other cultures as well.

Speaker 3 Yeah, the cycles are Babylonian, basically, taken over into the Greek world. Well, thank you very much indeed.
Thank you. I think a lot of people are going to enjoy that enormously.

Speaker 3 So, thank you very much. Thank you.
Hold on. Simon's coming in with his

Speaker 3 news.

Speaker 3 News.

Speaker 3 Another cup of tea.

Speaker 3 Two teas, Melvin. Another cup of tea.
Thank you. Three teas.
Thank you very much.

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