0:00:02 > 0:00:06If it hadn't been discovered when it was, in 1901,
0:00:06 > 0:00:10no-one would possibly believe that it could exist
0:00:10 > 0:00:12because it's so sophisticated.
0:00:13 > 0:00:15This mechanism would be remarkable
0:00:15 > 0:00:19even if it was a less clever thing than it is.
0:00:19 > 0:00:24This is the story of one of the most extraordinary finds in history.
0:00:24 > 0:00:26This corroded bronze object
0:00:26 > 0:00:28is a machine that can look into the future.
0:00:28 > 0:00:34It was built 2,000 years ago in ancient Greece.
0:00:36 > 0:00:38Somebody, somewhere in ancient Greece,
0:00:38 > 0:00:43built an extraordinary machine that was actually a mechanical computer.
0:00:43 > 0:00:47100 years ago, a group of divers chanced upon a wreck
0:00:47 > 0:00:52full of the largest hoard of ancient Greek treasures ever found.
0:00:55 > 0:00:58Among the priceless ancient Greek bronze sculptures
0:00:58 > 0:01:03is another bronze object, no bigger than a modern laptop.
0:01:03 > 0:01:06It's known as the Antikythera mechanism.
0:01:13 > 0:01:16As a team of scientists try to unravel the secrets
0:01:16 > 0:01:20of the Antikythera mechanism, we're taken on a journey
0:01:20 > 0:01:23that charts the fall of one great ancient empire
0:01:23 > 0:01:26and the rise of another.
0:01:29 > 0:01:34An ancient Greek scientist had done a truly remarkable thing.
0:01:34 > 0:01:38He'd found a way of using bronze gear wheels to track the complex movements
0:01:38 > 0:01:41of the moon and probably all the planets as well.
0:01:41 > 0:01:45It was a mechanism of truly staggering genius.
0:01:45 > 0:01:50This is the story of the world's first computer.
0:01:57 > 0:01:59If it hadn't been for a storm
0:01:59 > 0:02:03on the rocky Greek island of Antikythera 100 years ago,
0:02:03 > 0:02:07one of the most bewilderingly complex objects ever to emerge
0:02:07 > 0:02:10from the ancient world might never have been found.
0:02:15 > 0:02:17After they had sheltered from the storm,
0:02:17 > 0:02:22a team of sponge divers decided to try their luck underwater.
0:02:56 > 0:02:59The sponge diver hadn't discovered a graveyard,
0:02:59 > 0:03:03he'd come upon a heap of marble and bronze sculptures.
0:03:03 > 0:03:08It was part of the biggest hoard of Greek treasure ever found.
0:03:08 > 0:03:13It had come from an overloaded Roman galley sunk 2,000 years ago
0:03:13 > 0:03:18as Rome's empire began to grab Greece's overseas colonies in the Mediterranean.
0:03:23 > 0:03:26By accident, the divers had rescued
0:03:26 > 0:03:30some of ancient Greece's most beautiful artefacts.
0:03:33 > 0:03:36But among the bronze and marble statues
0:03:36 > 0:03:39was perhaps the most important object of all,
0:03:39 > 0:03:43item 15,087 in the Athens Museum.
0:03:44 > 0:03:49It had soon split into several badly corroded lumps of bronze.
0:03:49 > 0:03:54Then, remarkably, researchers noticed tiny gear wheels in the machine.
0:03:54 > 0:03:58Much later, the Antikythera Mechanism,
0:03:58 > 0:04:00to the amazement of scientists,
0:04:00 > 0:04:05would be revealed as the world's first computer,
0:04:05 > 0:04:09built 2,000 years ago by a Greek genius.
0:04:09 > 0:04:12You're just amazed by the quality of the workmanship
0:04:12 > 0:04:16and suddenly you look and you see tiny Greek characters
0:04:16 > 0:04:19engraved into the actual metal itself.
0:04:19 > 0:04:23The shock they must have had when they first saw this and saw these gear wheels.
0:04:23 > 0:04:26They knew wooden gear wheels were used in Greek mills and so on,
0:04:26 > 0:04:31but nothing was known like these precision metal engineered gears.
0:04:31 > 0:04:34It was against the background of this Greek mystery
0:04:34 > 0:04:38that in the year 2000, a team of international scientists was formed
0:04:38 > 0:04:42by astronomer Professor Mike Edmunds to investigate the puzzle.
0:04:42 > 0:04:46As a group, they were an odd mixture of astronomers,
0:04:46 > 0:04:49historians of science and mathematicians.
0:04:49 > 0:04:52The Antikythera Mechanism is an incredible puzzle.
0:04:52 > 0:04:56Probably one of the most fiendish puzzles in history.
0:04:56 > 0:05:01We had no confidence ourselves that we would be able to solve it.
0:05:03 > 0:05:05Tony Freeth, a mathematician,
0:05:05 > 0:05:09co-ordinated and led some of the team's major investigations.
0:05:11 > 0:05:16So when we started, we thought we'd try and put the basic information together.
0:05:16 > 0:05:20Maybe the objects from the wreck would help has piece together some clues.
0:05:20 > 0:05:23How old was it? Where did it come from?
0:05:23 > 0:05:25We had many, many questions.
0:05:26 > 0:05:29In 1976, another expedition to the Antikythera wreck
0:05:29 > 0:05:33by the famous French diver, Jacques Cousteau,
0:05:33 > 0:05:34had given them their first clues.
0:05:34 > 0:05:40Cousteau discovered much cargo left after the initial find in 1900.
0:05:40 > 0:05:44There was more pottery, many more amphorae,
0:05:44 > 0:05:47some of the original timbers from the ship and bronze figurines.
0:05:47 > 0:05:51Cousteau believed it was a Roman galley.
0:05:52 > 0:05:56Significantly, his divers brought up bronze and silver coins -
0:05:56 > 0:05:59an archaeologist's dream for dating a treasure site.
0:06:03 > 0:06:07These are the coins that came from the expedition of Jacques Cousteau
0:06:07 > 0:06:09- in 1976.- Yes.
0:06:09 > 0:06:11A lot of silver and bronze coins.
0:06:11 > 0:06:15- 36 silver coins plus some bronze coins.- Some bronze coins.
0:06:15 > 0:06:18So this has a basket on it.
0:06:18 > 0:06:21It has a basket introduced by the Kings of Pergamon.
0:06:21 > 0:06:25Most of the coins were struck in Pergamon, around a third of them,
0:06:25 > 0:06:28and the rest were struck in Ephesus.
0:06:28 > 0:06:31What do you think they actually tell us about where the ship came from?
0:06:31 > 0:06:35They can tell us the ship came from Asia Minor.
0:06:35 > 0:06:37What date would this be?
0:06:37 > 0:06:42These are dated in the decade of 70BC to 60BC.
0:06:42 > 0:06:45These coins from the cargo had given us our first clues
0:06:45 > 0:06:49to the likely date and route of the ship's last voyage.
0:06:49 > 0:06:53So what were these Greek treasures and the strange Antikythera Mechanism
0:06:53 > 0:06:57doing on a Roman ship 2,000 years ago?
0:06:58 > 0:07:02Since the time of Homer, the Greeks had been great sailors,
0:07:02 > 0:07:04forging settlements and remote colonies
0:07:04 > 0:07:07in places such as Pergamon in Asia Minor
0:07:07 > 0:07:09and further north in the Black Sea.
0:07:09 > 0:07:11And everywhere the Greeks went,
0:07:11 > 0:07:14they left giant temples to the gods that protected them.
0:07:14 > 0:07:18But by the time the galley sank in the middle of the first century BC,
0:07:18 > 0:07:22these far-flung Greek settlements had become vulnerable
0:07:22 > 0:07:26to a hostile new power in the Mediterranean - Rome.
0:07:26 > 0:07:30But as we looked closer at the Antikythera cargo, we began to realise this wasn't
0:07:30 > 0:07:34a marauding Roman warship plundering Greek colonies
0:07:34 > 0:07:35but something more unusual.
0:07:36 > 0:07:38It was quite a big ship,
0:07:38 > 0:07:43probably huge for this period, for these Roman times.
0:07:43 > 0:07:46One of the, probably, biggest trade ships.
0:07:46 > 0:07:50Only a few harbours can receive these kind of ships
0:07:50 > 0:07:53and that is probably Telos,
0:07:53 > 0:07:56Pergamon and Ephesus - that region,
0:07:56 > 0:07:57Rhodes.
0:07:57 > 0:08:00Tell me about where these amphorae come from.
0:08:00 > 0:08:05Look, these amphoras, these five amphoras come from Rhodes,
0:08:05 > 0:08:07from the island of Rhodes.
0:08:07 > 0:08:10Two of them are coming from the island of Kos.
0:08:10 > 0:08:13They were containing wine.
0:08:13 > 0:08:18Tell me what you can say about the date of these amphorae and the date of the shipwreck.
0:08:18 > 0:08:23These are amphoras are between 65BC and 50BC.
0:08:24 > 0:08:26These dates were almost identical
0:08:26 > 0:08:30to those we'd found on the coins from the wreck.
0:08:36 > 0:08:39So we believe that the galley started its journey
0:08:39 > 0:08:42somewhere in the Greek colonies in Asia Minor,
0:08:42 > 0:08:46possibly Pergamon, possibly Ephesus, but somewhere along this coast.
0:08:46 > 0:08:51The ship would have sailed down, probably calling in at Kos,
0:08:51 > 0:08:54then on to Rhodes where it loaded more amphorae.
0:08:54 > 0:08:59And then set out, heavily overloaded, on the trade route back to Rome
0:08:59 > 0:09:04where it met its fate in a storm at the island of Antikythera.
0:09:12 > 0:09:16Some of the ship's cargo had been dated very accurately
0:09:16 > 0:09:18to between 70BC and 50BC.
0:09:18 > 0:09:23Perhaps this was now close to the vessel's last voyage.
0:09:23 > 0:09:26But the group couldn't be entirely sure the bronze mechanism
0:09:26 > 0:09:28really was 2,000-years-old.
0:09:28 > 0:09:31Perhaps it was a modern machine
0:09:31 > 0:09:33that had been dropped from a passing ship,
0:09:33 > 0:09:37by chance coming to rest on the wreck the sponge divers had found.
0:09:37 > 0:09:42So the team decided to scrutinise previous work done on the machine.
0:09:43 > 0:09:47The team were drawn to the work of Derek de Solla Price.
0:09:47 > 0:09:49He was an English-born physicist.
0:09:49 > 0:09:53He started work in the 1950s, first in Cambridge and later in Yale.
0:09:53 > 0:09:57He was the first to really examine the pieces in very great detail.
0:09:57 > 0:10:01He started doing radiographs and being able to see the insides of the mechanism.
0:10:01 > 0:10:03Suddenly, out of those radiographs,
0:10:03 > 0:10:06they realised there were 27 gears inside this thing.
0:10:06 > 0:10:08It was seriously complicated.
0:10:14 > 0:10:17Price was the first person to count the gear teeth,
0:10:17 > 0:10:19with Karakalos and his wife as well.
0:10:19 > 0:10:23And they did it by drawing around the gears and literally just counting
0:10:23 > 0:10:27so it wasn't surprising they didn't get it entirely accurate all the time.
0:10:27 > 0:10:31But all the two dimensional X-rays of the gears were overlapping,
0:10:31 > 0:10:33making this task formidable.
0:10:33 > 0:10:37Price realised if he could find the exact tooth count on a gear wheel,
0:10:37 > 0:10:40it might begin to unlock the mechanism.
0:10:40 > 0:10:47Price had identified a 127-tooth gear in the X-rays of the mechanism.
0:10:47 > 0:10:49He also had the number 235
0:10:49 > 0:10:53and these two numbers are very important in ancient Greek astronomy.
0:10:53 > 0:10:56Price wondered whether an ancient astronomer
0:10:56 > 0:11:01might be using the 127-gear wheel to follow the movement of the Moon.
0:11:01 > 0:11:03This was a revolutionary idea.
0:11:04 > 0:11:06Price was beginning to have sleepless nights,
0:11:06 > 0:11:09worrying about the authenticity of the mechanism.
0:11:09 > 0:11:12If the ancient Greek scientists
0:11:12 > 0:11:15could produce these gear systems 2,000 years ago,
0:11:15 > 0:11:18the whole history of Western technology would have to be rewritten.
0:11:23 > 0:11:27The team believe such sophistication was surely beyond
0:11:27 > 0:11:32the great achievements the ancient Greeks had made more than two millennia earlier.
0:11:32 > 0:11:35They are regarded as some of the most creative people
0:11:35 > 0:11:37the world has ever known.
0:11:37 > 0:11:412,500 years ago, they began a revolution in thinking
0:11:41 > 0:11:46followed by technical advances comparable to those of the industrial revolution.
0:11:46 > 0:11:49This peaked in the 5th century BC when Athens,
0:11:49 > 0:11:52the largest city state, produced magnificent art
0:11:52 > 0:11:55and architecture that is still revered today.
0:11:58 > 0:12:01In nine years, they built the huge temple of the Parthenon
0:12:01 > 0:12:04to their Goddess Athena on the sacred Acropolis rock
0:12:04 > 0:12:06that dominates Athens.
0:12:13 > 0:12:15Public discussion of ideas
0:12:15 > 0:12:19and oratory led to larger public events like theatre.
0:12:19 > 0:12:23This huge theatre at Epidavros could hold 14,000 spectators
0:12:23 > 0:12:26and it had superb acoustics.
0:12:26 > 0:12:30Drop a coin on the stage and it could be heard in the back row.
0:12:34 > 0:12:37The Ancient Greeks developed astronomy
0:12:37 > 0:12:40which they treated as a branch of mathematics.
0:12:40 > 0:12:43They were able to plot how heavenly bodies moved in space
0:12:43 > 0:12:48and calculate their distances and know the geometry of their orbits.
0:12:48 > 0:12:51Now, with the mysterious gear wheels, the team suspected
0:12:51 > 0:12:56ancient astronomers would try to mechanise the movements of the Sun,
0:12:56 > 0:12:57Moon and planets.
0:12:57 > 0:13:01Could they put astronomy and complex mathematics into a device
0:13:01 > 0:13:05and programme it to follow the motion of their closest neighbour,
0:13:05 > 0:13:06the Moon?
0:13:08 > 0:13:11The phases of the Moon were a fact of central importance
0:13:11 > 0:13:14for the Ancient Greeks to plan ceremonies
0:13:14 > 0:13:18such as the ones that were held in the Parthenon on the rock above me.
0:13:18 > 0:13:23The number 235 that Price had found was the mechanism's key
0:13:23 > 0:13:25to computing the cycles of the Moon.
0:13:25 > 0:13:29The Greeks knew that from one new moon to the next was a time
0:13:29 > 0:13:31averaging about 29 and a half days,
0:13:31 > 0:13:35but that made a problem for their calendar if they were going to have
0:13:35 > 0:13:3912 months in every year because 12 times 29 and a half
0:13:39 > 0:13:44makes only 354 days, 11 days short of the solar year, the natural year.
0:13:44 > 0:13:47So, the natural year with its seasons,
0:13:47 > 0:13:50and the calendar year, would quickly go out of sync.
0:13:50 > 0:13:53But the Greeks also knew that 19 solar years
0:13:53 > 0:13:57almost exactly equals 235 lunar months.
0:13:59 > 0:14:02That means that if you have a cycle of 19 calendar years,
0:14:02 > 0:14:05then your calendar, in the long term, is going to stay
0:14:05 > 0:14:07perfectly in line with the seasons.
0:14:07 > 0:14:09Through Price,
0:14:09 > 0:14:12the mechanism was beginning to yield one of its secrets.
0:14:14 > 0:14:18On the back of the mechanism was the remains of an upper dial
0:14:18 > 0:14:22with Price's 235 divisions representing the 19 year cycle.
0:14:26 > 0:14:29The Greeks called it the Metonic calendar.
0:14:29 > 0:14:31Why had these ancient astronomical numbers
0:14:31 > 0:14:33and a dial been built into the machine?
0:14:36 > 0:14:41The phases of the Moon were immensely useful to the Ancients.
0:14:41 > 0:14:44These told them when to plant crops, when to fight battles,
0:14:44 > 0:14:46the timing of their religious festivals
0:14:46 > 0:14:48and whether to travel at night.
0:14:50 > 0:14:53The 127 tooth gear had given Price
0:14:53 > 0:14:55a clue to another one of its functions.
0:14:55 > 0:14:58The ancient Greek astronomers realised that,
0:14:58 > 0:15:02whilst it takes 29.5 days for the Moon to catch up with the Sun,
0:15:02 > 0:15:06it takes only 27 and a third days for it to get back
0:15:06 > 0:15:08to the same star in the sky.
0:15:08 > 0:15:13So that's the length of time it takes for the Moon to go once round the Earth.
0:15:13 > 0:15:17If you do the arithmetic, you find that in that 19 year cycle,
0:15:17 > 0:15:22this means there are 254 orbits of the Moon around the Earth.
0:15:22 > 0:15:25But that's a lot of teeth to put on a small gear.
0:15:25 > 0:15:29What the designer did instead was to take half of that number -
0:15:29 > 0:15:31half of 254 is 127,
0:15:31 > 0:15:35and then use other gears to multiply its effect up to 254.
0:15:37 > 0:15:42Price had discovered the 127 tooth gear, one of the other main functions
0:15:42 > 0:15:47of the mechanism - a display of the Moon's revolutions around the Earth.
0:15:47 > 0:15:53We now had two prime numbers - 19 and 127,
0:15:53 > 0:15:57which both had crucial functions. Were there more?
0:15:59 > 0:16:01After 20 years of intense research,
0:16:01 > 0:16:06Derek Price thought he'd solved the puzzle of the mechanism.
0:16:06 > 0:16:08But he hadn't used up all the gears, particularly a large gear
0:16:08 > 0:16:15at the back which he thought had 222 or 223 teeth, so we became sure
0:16:15 > 0:16:18that Derek Price hadn't solved the puzzle of the mechanism.
0:16:20 > 0:16:23We were desperate to see inside the Antikythera mechanism.
0:16:23 > 0:16:25One day I was looking at a science journal
0:16:25 > 0:16:28and I saw this exquisite X-ray picture of a goldfish.
0:16:30 > 0:16:33Another picture I saw was of a locust
0:16:33 > 0:16:36with all this fine detail of the internal structure.
0:16:38 > 0:16:41Could we use these techniques
0:16:41 > 0:16:45to look inside the fragments in three dimensions?
0:16:45 > 0:16:47Tony Freeth took a chance.
0:16:47 > 0:16:52He phoned a UK company who are world experts in X-ray technology.
0:16:52 > 0:16:55Could he convince them of the importance of the mechanism?
0:16:55 > 0:16:57To begin with, I wasn't interested.
0:16:57 > 0:17:02My colleagues told me it was some ancient bronze calcified lump.
0:17:02 > 0:17:04I determined to ring up Dr Freeth
0:17:04 > 0:17:07and say, "I'm really sorry, but we are unable to do this because
0:17:07 > 0:17:12"we haven't got a system powerful enough to penetrate the sample."
0:17:12 > 0:17:16After an hour's conversation, I was pretty much convinced that this
0:17:16 > 0:17:19was something we had to do.
0:17:19 > 0:17:23Roger decided to build a special prototype machine for us
0:17:23 > 0:17:25to X-ray the Antikythera mechanism.
0:17:25 > 0:17:27It was an extraordinary decision.
0:17:27 > 0:17:30The financial director was absolutely furious.
0:17:30 > 0:17:32He stormed out of our meeting,
0:17:32 > 0:17:35declaring I was going to bankrupt the company.
0:17:35 > 0:17:39The Antikythera mechanism is extremely fragile.
0:17:39 > 0:17:44So, Roger agreed to take this eight tonne machine to Athens
0:17:44 > 0:17:46to study the fragments.
0:17:57 > 0:18:00When they got to Athens, the police cleared the streets
0:18:00 > 0:18:02so that we could get the lorry through.
0:18:04 > 0:18:08It was an X-ray machine the size of a small van, basically,
0:18:08 > 0:18:09but weighing eight tonnes.
0:18:09 > 0:18:14With the help of three forklift trucks, we managed to shoehorn
0:18:14 > 0:18:16the X-ray machine through the entrance
0:18:16 > 0:18:18into the basement of the museum.
0:18:18 > 0:18:22You could describe it as a very high-tech machine to crack
0:18:22 > 0:18:26one of the deepest and most extraordinary conundrums that
0:18:26 > 0:18:28have come from the ancient world.
0:18:28 > 0:18:31This thing is remarkable beyond belief.
0:18:31 > 0:18:36The Antikythera mechanism itself is extremely fragile
0:18:36 > 0:18:38and, since it was brought here more than 100 years ago,
0:18:38 > 0:18:41it's never moved from this museum.
0:18:44 > 0:18:48So, we had to bring the technology to the mechanism rather than take
0:18:48 > 0:18:50the mechanism to the technology.
0:19:03 > 0:19:06We'd made this huge team effort.
0:19:06 > 0:19:10We arrived there with the machine without any confidence
0:19:10 > 0:19:12that we would find out anything new.
0:19:14 > 0:19:18And the way that the technique works is that you put
0:19:18 > 0:19:21a fragment on a turntable and you rotate the fragment in front
0:19:21 > 0:19:26of the detector and take maybe 3,000 different x-ray projections.
0:19:26 > 0:19:30The computer then puts this all together, so you've got 3D X-rays.
0:19:32 > 0:19:36And when we saw the first image of fragment A,
0:19:36 > 0:19:39it was absolutely amazing.
0:19:42 > 0:19:44It was like a new world, really.
0:19:53 > 0:19:56It's almost like going to an unknown, underwater world.
0:20:10 > 0:20:14Now we actually had the data to enable us to really tackle
0:20:14 > 0:20:17this problem of how it worked for the first time.
0:20:19 > 0:20:23I decided to make a digital model of the mechanism in order to try
0:20:23 > 0:20:26and understand better how it worked.
0:20:28 > 0:20:32What's remarkable is how much is crammed into such a small space
0:20:32 > 0:20:34in the main fragment.
0:20:34 > 0:20:36All the gears are packed together in layers,
0:20:36 > 0:20:38almost touching each other.
0:20:38 > 0:20:41We found 27 gears.
0:20:41 > 0:20:45Probably, in the complete mechanism, there were 50 or 60 gears.
0:20:47 > 0:20:52It upsets all our ideas about what the Ancient Greeks were capable of.
0:20:52 > 0:20:56It rewrites the history of technology.
0:20:56 > 0:21:01It tells us that things were going on in 2nd century BC Greece
0:21:01 > 0:21:03which we have no idea about.
0:21:05 > 0:21:08Would our new data from the X-rays solve the puzzle
0:21:08 > 0:21:09of the largest gear wheel?
0:21:09 > 0:21:15It was broken and had either 222 or 223 teeth.
0:21:16 > 0:21:19223 was another prime number.
0:21:19 > 0:21:23The two prime numbers we already knew about were 19
0:21:23 > 0:21:26and 127 in the gear that Price had found.
0:21:28 > 0:21:32Our plan was to follow this trail of prime numbers to see
0:21:32 > 0:21:36if they would unlock the astronomical secrets of the mechanism.
0:21:47 > 0:21:52But all this time, the international research team had a rival.
0:21:53 > 0:21:59Michael Wright had been working in London on the riddle of the mechanism for 25 years.
0:21:59 > 0:22:03Slowly, you get the metal to work around the instruments
0:22:03 > 0:22:06so it gets nearly symmetrical, then you can put it on there.
0:22:06 > 0:22:09Where it's tight...
0:22:09 > 0:22:12Michael Wright makes things - from musical instruments
0:22:12 > 0:22:15to a working model of the Antikythera mechanism.
0:22:15 > 0:22:17He was formerly an expert on engineering
0:22:17 > 0:22:19at the Science Museum in London.
0:22:22 > 0:22:26Previous research showed the bronze fragments with their gear wheels
0:22:26 > 0:22:30had once been fitted into a wooden box that hadn't survived.
0:22:30 > 0:22:34So, Wright had built his multi-geared machine into a box
0:22:34 > 0:22:37powered by a handle on the side.
0:22:42 > 0:22:46Michael Wright's own model included a radical addition
0:22:46 > 0:22:48to that of the international team's.
0:22:48 > 0:22:52Using earlier ideas by Price, he built a very complex
0:22:52 > 0:22:55and highly ingenious planetarium on the front of his mechanism.
0:22:59 > 0:23:02It's very obvious there is a lot of mechanism lost
0:23:02 > 0:23:05from the front of this, which is the big fragment.
0:23:05 > 0:23:08There was a pattern of pillars on this wheel, it had structure,
0:23:08 > 0:23:12some sort of structure that revolved like a merry-go-round.
0:23:12 > 0:23:18And what I ended up with was models of the planets.
0:23:18 > 0:23:22This is a model of the Greek cosmos, geocentric -
0:23:22 > 0:23:24you can think of this cover plate in the middle as representing
0:23:24 > 0:23:27the Earth and everything goes round it.
0:23:27 > 0:23:29The easy one to spot is the Moon because that's
0:23:29 > 0:23:33the fastest-moving thing on the dial, and it's the front pointer.
0:23:33 > 0:23:36The night sky was the ancient Greeks' television.
0:23:36 > 0:23:38What else were you going to look at at night?
0:23:38 > 0:23:40People were much more aware of the sky.
0:23:40 > 0:23:43The calendar was organised according to the Moon.
0:23:43 > 0:23:47Official positions changed, debts became payable on the new moon.
0:23:47 > 0:23:51You had to have a calendar that in some way reconciled the year,
0:23:51 > 0:23:54controlled by the Sun, with the month, controlled by the Moon.
0:23:54 > 0:23:58They are tricky numbers, and they're built into the model.
0:23:58 > 0:24:02These numbers had to be translated into gearwheels with awkward
0:24:02 > 0:24:05teeth counts, like 53 and 127.
0:24:05 > 0:24:08How did the ancient engineers do this?
0:24:08 > 0:24:11Michael Wright had the simple answer.
0:24:11 > 0:24:16There's nothing difficult about any number. 53's no harder than 54.
0:24:16 > 0:24:19We think that the Greek mechanics started with
0:24:19 > 0:24:21a prepared sheet of metal.
0:24:21 > 0:24:24He didn't have a hacksaw so he had to cut it out with a hammer and chisel.
0:24:31 > 0:24:35What I usually do for almost any number is to divide
0:24:35 > 0:24:40the wheel into six to begin with, by stepping the radius round.
0:24:45 > 0:24:47Now, I ought to be fitting
0:24:47 > 0:24:51eight and a large fraction into each of those six divisions.
0:24:53 > 0:24:56So now, I'm going to attack it with a file and make teeth.
0:25:06 > 0:25:12That's 53 teeth. That's ready to go into my Antikythera mechanism.
0:25:12 > 0:25:14I suppose my Hellenistic workman friend
0:25:14 > 0:25:18would've taken about half-an-hour to make that.
0:25:21 > 0:25:24Meanwhile, as Tony Freeth created his own digital model,
0:25:24 > 0:25:26he was suspicious of Wright's use of gearwheels
0:25:26 > 0:25:29with odd numbers, like 53 teeth.
0:25:30 > 0:25:3653 teeth? Why 53 teeth? It seemed to have no function.
0:25:36 > 0:25:39Odd prime number, no function.
0:25:39 > 0:25:43And I thought 54 was a much more likely number.
0:25:43 > 0:25:46You know, divisible by two, divisible by three several times.
0:25:46 > 0:25:51So in my model, I changed Wright's 53 to 54.
0:25:51 > 0:25:55And it proved to be a huge mistake.
0:25:55 > 0:26:00This tiny change would escalate into a major problem in the future.
0:26:06 > 0:26:08But there was a more pressing problem.
0:26:08 > 0:26:11None of the investigators working on the machine had ever
0:26:11 > 0:26:13been able to explain the function of the large wheel,
0:26:13 > 0:26:20the one with either 222 or 223 teeth, at the back of the mechanism.
0:26:20 > 0:26:23We were desperate for more data.
0:26:23 > 0:26:26We knew that the surfaces of many of the fragments were
0:26:26 > 0:26:29covered in inscriptions which were incredibly hard to read.
0:26:29 > 0:26:32Then I read about this technique invented by a guy
0:26:32 > 0:26:34called Tom Malzbender at Hewlett-Packard.
0:26:34 > 0:26:38It was a brilliant technique for enhancing the surfaces,
0:26:38 > 0:26:39surface details.
0:26:39 > 0:26:42One of the ways this technique had been used
0:26:42 > 0:26:46is on paintings, for example, at the National Gallery in London,
0:26:46 > 0:26:48to look at the surfaces of paintings,
0:26:48 > 0:26:49and looking at brush strokes,
0:26:49 > 0:26:53the fingerprints, the essential form.
0:26:53 > 0:26:57This can reveal things that are under the surface.
0:26:57 > 0:27:00Here, for example, is a painting by Frans Hals, and if I move
0:27:00 > 0:27:04the virtual light, I can see the brush strokes on the painting,
0:27:04 > 0:27:07I can see how the painter's applied all the brush strokes.
0:27:07 > 0:27:10We thought this would be an absolutely brilliant
0:27:10 > 0:27:13technique to use on the Antikythera inscriptions.
0:27:13 > 0:27:17I got on very well with Tom and I then set about persuading him
0:27:17 > 0:27:20to come to Athens to use his technique
0:27:20 > 0:27:23on the Antikythera mechanism.
0:27:23 > 0:27:26Tom had a brilliant insight, which is you can
0:27:26 > 0:27:31look at a surface by taking a series of still photographs,
0:27:31 > 0:27:362-D still photographs, with lighting from 50 different angles.
0:27:36 > 0:27:38Flashlights, arranged in a dome, flash
0:27:38 > 0:27:42and a picture's taken with the light at all these different angles.
0:27:42 > 0:27:45This means that a computer can put all this information together
0:27:45 > 0:27:49and it can take away all the confusions
0:27:49 > 0:27:52of the surface colouration and the surface texturing
0:27:52 > 0:27:57and show you the essential form of the surface.
0:28:05 > 0:28:07- Marvellous.- This is beautiful.
0:28:07 > 0:28:10THEY COMMENT IN GREEK
0:28:12 > 0:28:14APPLAUSE
0:28:18 > 0:28:22You can actually look in detail at an inscription, say,
0:28:22 > 0:28:25and the clarity of the image leaps out at you.
0:28:25 > 0:28:29THEY LAUGH AND SPEAK GREEK
0:28:36 > 0:28:38Both this technique
0:28:38 > 0:28:41and the X-rays proved invaluable in reading the inscriptions.
0:28:41 > 0:28:44These inscriptions were very tiny.
0:28:44 > 0:28:46Maximum, a couple of millimetres high.
0:28:46 > 0:28:49I was working overnight in front of my computer,
0:28:49 > 0:28:52trying to transcribe what I was seeing.
0:28:52 > 0:28:56The letters appeared like ghosts within the fragments.
0:28:58 > 0:29:00Lambda...
0:29:02 > 0:29:04Epsilon...
0:29:04 > 0:29:05HE SPEAKS GREEK
0:29:08 > 0:29:15Spiral sections - 235.
0:29:16 > 0:29:20Should be the 19-year calendar.
0:29:20 > 0:29:25One particular night, I discovered a completely unknown layer of text.
0:29:25 > 0:29:28I tilted the angle a little bit
0:29:28 > 0:29:30and a whole new layer of inscription appeared.
0:29:30 > 0:29:32My heart was beating.
0:29:32 > 0:29:37And suddenly, I started reading mechanical words about gears.
0:29:37 > 0:29:39The word "gear" appeared for the first time,
0:29:39 > 0:29:43like a kind of user manual. This was totally unexpected.
0:29:44 > 0:29:47And new data from the inscriptions was producing another
0:29:47 > 0:29:48significant breakthrough.
0:29:48 > 0:29:52Sigma-Kappa-Gamma...
0:29:52 > 0:29:54What is that? How much is there?
0:29:54 > 0:29:58- 223.- 223 is there?- Yes.
0:29:58 > 0:30:00The line below.
0:30:00 > 0:30:03- Definitely 223?- Yes, 223.
0:30:03 > 0:30:07Did this mean the large gearwheel at the back of the mechanism
0:30:07 > 0:30:09actually had 223 teeth?
0:30:10 > 0:30:12If so, what was its function?
0:30:12 > 0:30:15Then, with a chance discovery in the museum,
0:30:15 > 0:30:18the mystery began to unravel.
0:30:18 > 0:30:21I went to the stores of the bones collections
0:30:21 > 0:30:28and I started looking at all the places the Antikythera were.
0:30:28 > 0:30:33So I found this tray, with eight boxes.
0:30:33 > 0:30:36And then, I was looking around
0:30:36 > 0:30:40and saw some other small fragments in the boxes.
0:30:40 > 0:30:43Altogether there were 82 fragments.
0:30:43 > 0:30:46One of the new fragments in particular stood out.
0:30:46 > 0:30:48Mary had labelled it as "Fragment F",
0:30:48 > 0:30:51but it also appeared to contain part of a curved dial.
0:30:53 > 0:30:56Measuring only a few centimetres, Fragment F would turn out
0:30:56 > 0:31:00to be the key to the big wheel and the entire mechanism.
0:31:01 > 0:31:03A couple of weeks later,
0:31:03 > 0:31:07Tony Freeth started to examine the 3-D X-rays taken of Fragment F.
0:31:09 > 0:31:13I suddenly realised with mounting excitement that Fragment F
0:31:13 > 0:31:16formed a new scale on the lower back dial of the mechanism.
0:31:16 > 0:31:20In order to understand this new four-turn spiral dial,
0:31:20 > 0:31:22I wanted to count the scale divisions round the whole dial,
0:31:22 > 0:31:24make an estimate of them.
0:31:24 > 0:31:28So I started to enter the data into an advanced computer programme
0:31:28 > 0:31:32and the result seemed to come out as 220-225.
0:31:32 > 0:31:37So I became sure that it must be the magic number 223.
0:31:39 > 0:31:42We found the importance of the number 223
0:31:42 > 0:31:46at the British Museum in London.
0:31:46 > 0:31:49Three centuries before the golden age of Athens, around 700BC,
0:31:49 > 0:31:52Babylonian astronomers had made the breakthrough.
0:31:52 > 0:31:57Over hundreds of years, they'd written thousands of astronomical
0:31:57 > 0:32:02tablets, many recording the huge significance of the number 223.
0:32:02 > 0:32:05The Babylonians called it the "18-year period".
0:32:08 > 0:32:11John, tell me what all these tablets are here.
0:32:11 > 0:32:15We have maybe three or four thousand astronomical tablets, ranging from
0:32:15 > 0:32:19reports sent to the king by scholars, advising him on astronomical
0:32:19 > 0:32:22matters to how to interpret omens and what this meant for his kingship.
0:32:22 > 0:32:25Tell me about the 18-year period.
0:32:25 > 0:32:27The 18-year period describes
0:32:27 > 0:32:30a cycle of 223 months used to predict eclipses.
0:32:30 > 0:32:32This is what today we'd call the Saros Cycle.
0:32:32 > 0:32:36By looking at past observations, they saw that after 223 months,
0:32:36 > 0:32:39the 18-year cycle, eclipses of the same kind -
0:32:39 > 0:32:42say lunar eclipses - would repeat with very similar appearances.
0:32:43 > 0:32:45Tell me, John,
0:32:45 > 0:32:48how the kings of Babylon reacted to an eclipse prediction.
0:32:48 > 0:32:51A substitute, usually a criminal or someone like that, would be
0:32:51 > 0:32:54officially appointed to the throne
0:32:54 > 0:32:56and the real king would officially abdicate.
0:32:56 > 0:32:58This is an example of one of the tablets that is a letter
0:32:58 > 0:33:01describing this substitute king ritual.
0:33:01 > 0:33:04It mentions down here that the substitute king ascended
0:33:04 > 0:33:08the throne and took these bad omens, these signs, onto himself.
0:33:11 > 0:33:13Once they were deemed to have done their worst,
0:33:13 > 0:33:16the substitute king would be killed and the real king would
0:33:16 > 0:33:19come back to the throne, unharmed by what had happened.
0:33:19 > 0:33:21Since the substitute king was killed,
0:33:21 > 0:33:24the omens were clearly correct then!
0:33:24 > 0:33:25Indeed! Of course!
0:33:27 > 0:33:31This solved the mystery of the large gear at the back.
0:33:31 > 0:33:38It must have 223 teeth to turn the pointer of the 223-month Saros dial.
0:33:38 > 0:33:40The team had found something remarkable.
0:33:40 > 0:33:43They'd uncovered a machine that could look into the future.
0:33:43 > 0:33:45It could predict eclipses.
0:33:45 > 0:33:48What we realised was that the ancient Greeks
0:33:48 > 0:33:51had built a machine to predict the future.
0:33:51 > 0:33:53It was an extraordinary idea,
0:33:53 > 0:33:56that you could take scientific theories of the time
0:33:56 > 0:34:02and mechanise them to see what their outputs would be many decades hence.
0:34:02 > 0:34:06It was essentially the first time that the human race
0:34:06 > 0:34:08had created a computer.
0:34:10 > 0:34:14The gearwheels in the mechanism programmed the computer.
0:34:14 > 0:34:16But where was the output data displayed?
0:34:16 > 0:34:19The clues were in Fragment F.
0:34:21 > 0:34:24When you first look at the X-rays from Fragment F,
0:34:24 > 0:34:26there's nothing much there.
0:34:26 > 0:34:30Then these scales emerge as you go down through the layers.
0:34:30 > 0:34:34And not only scales, but you see these little scale divisions,
0:34:34 > 0:34:36blocks of characters here.
0:34:36 > 0:34:39These look to me a little bit like Egyptian hieroglyphs.
0:34:39 > 0:34:42So I called them glyphs.
0:34:45 > 0:34:50The glyphs must be the eclipse predictions.
0:34:50 > 0:34:54I soon realised that the first letter here is a sigma - sigma standing for
0:34:54 > 0:34:58the letter S, standing for Selene, the goddess of the moon.
0:34:58 > 0:35:02That must indicate a lunar eclipse.
0:35:02 > 0:35:06I next realised that the letter eta, H in the Greek alphabet,
0:35:06 > 0:35:09must stand for Helios, the sun,
0:35:09 > 0:35:12so this must indicate a SOLAR eclipse.
0:35:14 > 0:35:17What became really tough was to try and decode the next symbol,
0:35:17 > 0:35:20the anchor-like symbol, and this took me a long time.
0:35:22 > 0:35:25By chance, I found a book on Greek horoscopes.
0:35:25 > 0:35:30Amongst a whole mass of symbols, I found this symbol in the document -
0:35:30 > 0:35:35it was short for the word "hora" meaning "hour".
0:35:36 > 0:35:43What that told us was that not only did this mechanism predict eclipses,
0:35:43 > 0:35:45but it predicted the hour of the eclipse, as well.
0:35:45 > 0:35:48As the hand sweeps along the scale,
0:35:48 > 0:35:51here it's just reaching a lunar eclipse,
0:35:51 > 0:35:54and here we've got a solar eclipse in this month,
0:35:54 > 0:35:57followed by a lunar eclipse in that month.
0:35:57 > 0:36:00Our research group pooled our resources in a discussion
0:36:00 > 0:36:04on the internet, and Yanis Bitsakis in Athens
0:36:04 > 0:36:09found the phrase, "the colour is black" in the eclipse inscriptions.
0:36:09 > 0:36:12Alexander Jones in Toronto found this really exciting,
0:36:12 > 0:36:16and he then discovered the phrase, "the colour is fire red".
0:36:21 > 0:36:25We were discovering a very sophisticated machine
0:36:25 > 0:36:28that not only was predicting eclipses decades in advance
0:36:28 > 0:36:31and what time of the day or night they were happening,
0:36:31 > 0:36:33but even the direction the shadow was going to cross
0:36:33 > 0:36:36and what colour the eclipsed sun or moon was going to be.
0:36:40 > 0:36:44We're watching a total eclipse of the moon in Athens.
0:36:48 > 0:36:52For the ancient astronomers, the eclipses had a special significance,
0:36:52 > 0:36:56but for most Greeks, eclipses could have a much more dire and ominous significance.
0:36:59 > 0:37:03In 413 BC, a lunar eclipse led to a fatal maritime disaster
0:37:03 > 0:37:06for the Athenian fleet at Syracuse.
0:37:06 > 0:37:10Athens was engaged in a long war with Corinth
0:37:10 > 0:37:13and its colony Syracuse in Sicily.
0:37:13 > 0:37:16More than 130 Athenian triremes
0:37:16 > 0:37:20and 130 transport ships were blockading the harbour at Syracuse.
0:37:21 > 0:37:25On the night of 27th August, 413 BC,
0:37:25 > 0:37:27there was a total lunar eclipse.
0:37:27 > 0:37:32Nicias, the superstitious Athenian admiral of the fleet,
0:37:32 > 0:37:34consulted a soothsayer on board,
0:37:34 > 0:37:36who said the red eclipse of the moon was a bad omen.
0:37:36 > 0:37:41The fleet should not put to sea for thrice times nine days.
0:37:41 > 0:37:43In the ensuing battle,
0:37:43 > 0:37:47Nicias lost half his ships from arrows fired from the shore.
0:37:53 > 0:37:56The computer predicted eclipses through the Saros dial
0:37:56 > 0:37:58on the lower back of the mechanism.
0:37:58 > 0:38:01It was dependent upon gearwheels,
0:38:01 > 0:38:04following the repeating cycles of the moon.
0:38:04 > 0:38:06But there was a new puzzle.
0:38:06 > 0:38:10The team knew that the moon moves round the Earth
0:38:10 > 0:38:11in an elliptical motion.
0:38:11 > 0:38:14That means it moves fastest when it's closest to Earth
0:38:14 > 0:38:16and slower when it's furthest away.
0:38:18 > 0:38:21How could the mechanism's designer possibly make gears
0:38:21 > 0:38:24that tracked this fluctuating path of the moon?
0:38:24 > 0:38:27Michael Wright made an absolutely brilliant
0:38:27 > 0:38:29observation from his X-rays.
0:38:31 > 0:38:35He discovered that one of the gears at the back of the mechanism
0:38:35 > 0:38:40mounted on this large 223 tooth gear had a pin on it.
0:38:40 > 0:38:45This is the pin and slot mechanism.
0:38:45 > 0:38:47There's a wheel in the back of the instrument.
0:38:47 > 0:38:49You can see with the naked eye
0:38:49 > 0:38:51that it's got some sort of a slot in it.
0:38:51 > 0:38:53The next thing you see
0:38:53 > 0:38:57is this round ghost in the slot.
0:38:57 > 0:39:00There is a pin.
0:39:00 > 0:39:03You might think, well, they'll just turn together
0:39:03 > 0:39:05and that's a completely useless device,
0:39:05 > 0:39:09but he made this very critical discovery, that the gear with the pin
0:39:09 > 0:39:14turns on a slightly different axis than the gear with the slot.
0:39:14 > 0:39:20So this mechanical device induces a variability in the motion of one of the gears.
0:39:23 > 0:39:26And amazingly, the pin and slot device,
0:39:26 > 0:39:30built into the mechanism, plotted the variable motion of the moon.
0:39:31 > 0:39:34So you have a variable motion, which I can show you best in the model.
0:39:34 > 0:39:38When the wheels are like this,
0:39:38 > 0:39:40and the pin is at the inside of the slot,
0:39:40 > 0:39:43the driven wheel on top is going fast.
0:39:43 > 0:39:45When we come round here,
0:39:45 > 0:39:49and the pin has moved to the outside of the slot,
0:39:49 > 0:39:51the driven wheel is going slow.
0:39:51 > 0:39:56And this is modelling the way that the moon's speed in the sky actually varies.
0:39:56 > 0:39:59But when Wright originally found the pin and slot device,
0:39:59 > 0:40:01he failed to understand what it was for.
0:40:03 > 0:40:07And he threw the idea away, so a tragedy for him, in a way,
0:40:07 > 0:40:13that he had the most brilliant observation in the history of the mechanism.
0:40:13 > 0:40:15I didn't know what it was doing there.
0:40:15 > 0:40:20I even came to wonder whether it was a sort of mechanical fossil.
0:40:22 > 0:40:27But there was yet another lunar complication the machine had to deal with.
0:40:27 > 0:40:31The ancient astronomers were fascinated with the motions of the moon,
0:40:31 > 0:40:34and nothing is easy about the motion of the moon.
0:40:34 > 0:40:35It's very complicated stuff.
0:40:35 > 0:40:40In modern terms, we know the moon goes round in an elliptical orbit,
0:40:40 > 0:40:43but that ellipse isn't stationary.
0:40:43 > 0:40:47It rotates very slowly in a period of about nine years.
0:40:47 > 0:40:50Based on cycles I knew were part of the mechanism,
0:40:50 > 0:40:52the Metonic and Saros cycles,
0:40:52 > 0:40:56I deduced the ancient Greeks
0:40:56 > 0:41:01had calculated this annual rate of rotation to be 0.112579655
0:41:01 > 0:41:04to nine places of decimals.
0:41:04 > 0:41:08I thought, "Surely the mechanism can't calculate to this degree of precision?
0:41:08 > 0:41:11"That would be virtually impossible."
0:41:11 > 0:41:15I puzzled over how the designer could have possibly built gears
0:41:15 > 0:41:19to track the rotation of the moon's ellipse once every nine years.
0:41:20 > 0:41:25In my model, I drew the large 223 gear that helped track the moon's movements
0:41:25 > 0:41:27with a 27-tooth gear.
0:41:27 > 0:41:31I changed Wright's 53-tooth gear to 54 teeth,
0:41:31 > 0:41:35exactly double the 27 of my input gear.
0:41:36 > 0:41:41Then I had my own Eureka moment. I was on the plane to Athens and playing around with the figures.
0:41:41 > 0:41:46I knew the input gear had 27 teeth, so I put that into my calculator
0:41:46 > 0:41:49and calculated the result.
0:41:49 > 0:41:52To my deep disappointment, it was too big.
0:41:54 > 0:41:56So I thought maybe it's only 26 teeth,
0:41:56 > 0:42:00so I put that into the calculator, and it was too small.
0:42:00 > 0:42:05I was a mathematician, and mathematicians often have slightly crazy ideas,
0:42:05 > 0:42:11so I tried putting in a gear with 26.5 teeth
0:42:11 > 0:42:14and I pressed the key on the calculator
0:42:14 > 0:42:19and the result was 0.112579655,
0:42:19 > 0:42:22exactly the right answer to nine places of decimals.
0:42:22 > 0:42:27It just hit me like a thunderbolt. Twice 26.5 is 53.
0:42:27 > 0:42:33Michael Wright had been correct about the 53-tooth gear.
0:42:33 > 0:42:36The riddle of the 53-tooth gear had been solved at last.
0:42:37 > 0:42:42It turns the large 223 gear with just the right nine-year rotation,
0:42:42 > 0:42:46so that the pin and slot exactly models the ancient Greek theory
0:42:46 > 0:42:48of the moon's variable motion.
0:42:53 > 0:42:58We'd followed the trail of clues in the prime numbers, the numbers 19,
0:42:58 > 0:43:05127, 223, and then finally 53, to understand how the mechanism worked.
0:43:05 > 0:43:09It was just an amazing moment when everything came together.
0:43:09 > 0:43:13'We knew now what all the numbers in the tooth counts were,
0:43:13 > 0:43:17'which had been a complete mystery before, and not understood.
0:43:17 > 0:43:21'It was just a quite incredible moment.'
0:43:23 > 0:43:27The team's next quest however, was just as formidable.
0:43:27 > 0:43:32Who had invented this extraordinary machine 2,000 years ago?
0:43:32 > 0:43:36This investigation would throw up many more surprises.
0:43:36 > 0:43:39We thought the answer to the question - "who made the mechanism?"
0:43:39 > 0:43:42- might lie inside the mechanism itself.
0:43:45 > 0:43:49Tony Freeth, in London, and Alexander Jones, on the other side of the Atlantic,
0:43:49 > 0:43:53were deciphering Greek month names on the Metonic upper back spiral.
0:43:53 > 0:43:55Then, the breakthrough happened.
0:43:57 > 0:44:00Every Greek state had its own distinctive calendar.
0:44:00 > 0:44:03Four of the month names stood out as being really quite rare.
0:44:03 > 0:44:07There was one called Lanotropios...
0:44:07 > 0:44:10another Dodekateus...
0:44:10 > 0:44:14a third called Psydreus...
0:44:14 > 0:44:21and a fourth one called Phoinikaios, which was the first month of the calendar.
0:44:21 > 0:44:25I realised that these four months belonged to
0:44:25 > 0:44:28the calendar of ancient Corinth, and so they had to be
0:44:28 > 0:44:33coming from either Corinth itself or from one of the colonies that
0:44:33 > 0:44:37Corinth had founded, for example, Syracuse over the sea in Sicily.
0:44:38 > 0:44:41There were more tiny clues which might point towards
0:44:41 > 0:44:44a Corinthian designer of the mechanism.
0:44:44 > 0:44:48I was looking in the X-rays at this little subsidiary dial
0:44:48 > 0:44:51that's divided into four sectors, and I noticed this word "Nemea",
0:44:51 > 0:44:54and I had no idea what it meant.
0:44:55 > 0:45:01Almost immediately, Alexander Jones in Toronto e-mailed me with the answer.
0:45:01 > 0:45:05"Now you have a clear reading, Nemea, which I'm darned sure
0:45:05 > 0:45:07"is indicating a year when the Nemean games were held.
0:45:07 > 0:45:11"This was one of the four Pan-Hellenic games".
0:45:12 > 0:45:16The Nemean games, I discovered, took place every two years
0:45:16 > 0:45:19and were originally based on warlike events.
0:45:19 > 0:45:22Only warriors and their sons could take part.
0:45:24 > 0:45:27We were curious as to why one of ancient Greece's Pan-Hellenic games
0:45:27 > 0:45:30should appear on the mechanism,
0:45:30 > 0:45:33and how would this lead us to the designer?
0:45:35 > 0:45:38These are the starting blocks where the athletes began their races,
0:45:38 > 0:45:40going down the track.
0:45:40 > 0:45:44They would put their feet - their BARE feet -
0:45:44 > 0:45:47in the grooves, one foot in the rear groove, one foot in front groove.
0:45:47 > 0:45:50They would try to get their weight to move out just as the race began.
0:45:52 > 0:45:57They were the standard running events, one stadion in length was the premier event,
0:45:57 > 0:45:59roughly our 200-metre race.
0:45:59 > 0:46:03There was a race in armour where the athletes
0:46:03 > 0:46:08wore helmets and shields. There was the pancration,
0:46:08 > 0:46:11where people broke arms and strangled one another, a really lovely event(!)
0:46:11 > 0:46:15The Nemean games were on a par with the games at Olympia, Delphi and Isthmia -
0:46:15 > 0:46:18those four sites were the Crown sites.
0:46:18 > 0:46:22On this small dial, we found four sectors.
0:46:22 > 0:46:25The Nemean games, the Pythian games at Delphi,
0:46:25 > 0:46:27the Isthmian games at Corinth,
0:46:27 > 0:46:30and finally, the most prestigious games of them all,
0:46:30 > 0:46:33the games at Olympia, that happened every four years.
0:46:35 > 0:46:40The Olympic Games were believed to have been founded as early as 776 BC.
0:46:40 > 0:46:43This stadium held 45,000 people.
0:46:47 > 0:46:53We began to wonder why there had to be a dial on the mechanism
0:46:53 > 0:46:57showing the dates of these Panhellenic games, like the Olympics.
0:46:57 > 0:47:00Events that took place at such regular and simple intervals,
0:47:00 > 0:47:02every two and every four years,
0:47:02 > 0:47:04numbers they could count to easily on their fingers.
0:47:04 > 0:47:07The games could therefore have offered a fixed reference
0:47:07 > 0:47:09for the 19-year dial on the mechanism,
0:47:09 > 0:47:13a fixed date transcending the rise and fall of Greek states
0:47:13 > 0:47:16and their magistrates and the deaths of their kings.
0:47:19 > 0:47:21The surprising thing about this dial
0:47:21 > 0:47:24was the size of the lettering for the Isthmian games at Corinth.
0:47:24 > 0:47:28Far bigger than the prestigious games at Olympia,
0:47:28 > 0:47:31as if the Corinthian games were much more important.
0:47:31 > 0:47:33All the evidence now suggested
0:47:33 > 0:47:36that the mechanism's designer came from Corinth.
0:47:36 > 0:47:39But the team believe that it might have originated
0:47:39 > 0:47:43from Corinth's rich colony of Syracuse in Sicily.
0:47:47 > 0:47:49In the 3rd and 4th century BC,
0:47:49 > 0:47:54Syracuse was the second largest city state in the entire Greek world.
0:47:54 > 0:47:57Founded centuries before by poor Corinthian immigrants
0:47:57 > 0:48:01from the Greek mainland, it had prospered remarkably.
0:48:04 > 0:48:07Significantly, Syracuse was the home
0:48:07 > 0:48:10of the most brilliant of all the Greek mathematicians and engineers.
0:48:10 > 0:48:12Archimedes.
0:48:14 > 0:48:18As an astronomer, Archimedes determined the distance to the moon.
0:48:18 > 0:48:21As a mathematician, he showed how to calculate the volume of a sphere
0:48:21 > 0:48:25and how to calculate that fundamental number, pi.
0:48:28 > 0:48:32We believe that only a mathematician of Archimedes' status
0:48:32 > 0:48:35could have designed the Antikythera mechanism.
0:48:35 > 0:48:40As a brilliant inventor, he designed screw devices to lift water
0:48:40 > 0:48:43and he designed machines with grappling hooks
0:48:43 > 0:48:46that could grab enemy ships out of the water.
0:48:49 > 0:48:53Archimedes lived in Syracuse in the 3rd century BC.
0:48:53 > 0:48:57At that time, Rome was challenging the power of Greek cities in southern Italy.
0:48:57 > 0:49:00If rich Syracuse could be taken,
0:49:00 > 0:49:03all of Sicily would come under Roman control.
0:49:05 > 0:49:09Led by the Roman general Marcus Claudius Marcellus,
0:49:09 > 0:49:14Roman legions laid siege to Syracuse in 214 BC.
0:49:15 > 0:49:18Archimedes is believed to have designed cranes
0:49:18 > 0:49:21to pull Roman ships out of the water.
0:49:21 > 0:49:24Then, after two years of siege, by trickery,
0:49:24 > 0:49:27Roman soldiers got inside the city.
0:49:27 > 0:49:30General Marcellus gave orders that the city should be sacked
0:49:30 > 0:49:34but Archimedes' life be spared.
0:49:34 > 0:49:37But according to the historian Plutarch,
0:49:37 > 0:49:41a Roman soldier came upon an old man drawing circles in the dust.
0:49:41 > 0:49:44When he refused to obey an order,
0:49:44 > 0:49:48the legionnaire ran Archimedes through with his sword.
0:49:52 > 0:49:57Syracuse was stripped and its treasures were taken to Rome.
0:49:57 > 0:50:01Just two valuable objects were personally taken by General Marcellus.
0:50:01 > 0:50:06He states they were machines belonging to Archimedes.
0:50:06 > 0:50:11These, the team believe, might be early versions of the Antikythera mechanism.
0:50:13 > 0:50:15150 years later in Rome,
0:50:15 > 0:50:19the formidable orator and consul Cicero writes of a sighting of
0:50:19 > 0:50:23one of Archimedes' machines in the house of Marcus Marcellus,
0:50:23 > 0:50:28grandson of the victorious General Marcellus. Cicero writes...
0:50:28 > 0:50:32"Archimedes had thought up a way to represent accurately,
0:50:32 > 0:50:36"by a single device, those various and divergent movements
0:50:36 > 0:50:40"of the five planets with their different rates of speed,
0:50:40 > 0:50:43"as the same eclipse of the sun would happen on the globe
0:50:43 > 0:50:45"as it would actually happen."
0:50:46 > 0:50:49Were the rotating planets Cicero wrote about 2,000 years ago
0:50:49 > 0:50:53the final clues to the construction of the mechanism?
0:50:53 > 0:50:56Could Michael Wright's complex planetarium
0:50:56 > 0:50:58on the front of the mechanism
0:50:58 > 0:51:02be simplified to match the design genius of the original?
0:51:04 > 0:51:08I'm going to start off just by passing around some pretty pictures
0:51:08 > 0:51:10and then I'll explain why I'm passing them.
0:51:13 > 0:51:17These are mediaeval pictures, showing the cosmos,
0:51:17 > 0:51:21but the way that it's shown is an ancient Greek way.
0:51:21 > 0:51:23What you have is the Earth at the centre,
0:51:23 > 0:51:26and you've a set of rings, which are supposed to be spherical shells
0:51:26 > 0:51:30in which each of the planets, going from the moon up to Saturn are.
0:51:30 > 0:51:32The front display must have been a picture
0:51:32 > 0:51:36like these mediaeval ones, that show the cosmos in cross-section.
0:51:36 > 0:51:41This is a picture that I did from the tomography.
0:51:41 > 0:51:44It's a composite from several different layers
0:51:44 > 0:51:49so that we get a big chunk of the back cover inscription, all together.
0:51:49 > 0:51:52The part that I'm passing around is describing the planets.
0:51:52 > 0:51:55Venus' name is there. But probably all five are there.
0:51:55 > 0:51:59They're in the order that these pictures show,
0:51:59 > 0:52:02going from the moon and then Mercury, Venus,
0:52:02 > 0:52:04in the order going away from the Earth to the stars.
0:52:04 > 0:52:07Then, right after that, you get a line that says,
0:52:07 > 0:52:11"And beside the cosmos is..." And the text cuts off.
0:52:11 > 0:52:15Now, my idea about this is that the front display must have been
0:52:15 > 0:52:20a picture like these mediaeval ones, that show the cosmos in cross-section.
0:52:20 > 0:52:22I began to think, "How can you mechanise
0:52:22 > 0:52:26"these planets so it exactly predicts their positions
0:52:26 > 0:52:33"in a way that's simple and not over complex?"
0:52:33 > 0:52:36Mars is what I started with.
0:52:36 > 0:52:39You'll notice it's got four gears, it's got a pin in the slot,
0:52:39 > 0:52:44and it looks, in principle, almost identical to the moon mechanism.
0:52:44 > 0:52:46That's Mars. This is Jupiter.
0:52:46 > 0:52:50Very similar - four gears, pin in the slot,
0:52:50 > 0:52:52exactly the same sort of thing.
0:52:52 > 0:52:56And this is Saturn, which, at a quick glance,
0:52:56 > 0:52:58you might think IS the moon mechanism.
0:52:58 > 0:53:00It looks identical.
0:53:00 > 0:53:02The moon goes round once a month,
0:53:02 > 0:53:03Saturn goes round once every 30 years.
0:53:03 > 0:53:07And you finally end up with all the planetary mechanisms in here.
0:53:07 > 0:53:09I was just amazed.
0:53:09 > 0:53:14They all fit to create the cosmos on the Antikythera mechanism.
0:53:14 > 0:53:17Just like on Michael Wright's planetarium model,
0:53:17 > 0:53:19but much, much, simpler.
0:53:19 > 0:53:23That coincides exactly with Alex's picture of the cosmos.
0:53:23 > 0:53:25I'd love to take credit for discovering these things
0:53:25 > 0:53:29but I think I was rediscovering what the ancient Greeks did.
0:53:34 > 0:53:36But all this leaves a major unanswered question.
0:53:36 > 0:53:41What happened to the brilliant Greek technology that produced the world's first computer?
0:53:41 > 0:53:43Why was it never developed?
0:53:43 > 0:53:46Why was it lost from the Western world?
0:53:48 > 0:53:50As first the Greek world declined,
0:53:50 > 0:53:53followed by the collapse of the Roman Empire,
0:53:53 > 0:53:57historians believe Greek scientific texts were passed East.
0:53:57 > 0:54:01By the 4th century AD, information on the mechanism perhaps went first
0:54:01 > 0:54:05to the Byzantine world and then to Arab scholars.
0:54:05 > 0:54:11Michael Wright has a clue suggesting some of the mechanism's Greek technology
0:54:11 > 0:54:14would later become available to Islamic science.
0:54:14 > 0:54:16In 1983 a man came into the museum.
0:54:16 > 0:54:19He was a collector of astrolabes.
0:54:19 > 0:54:22He bought this from a dealer we think in the Lebanon.
0:54:22 > 0:54:26We believe we can date this instrument to about 520 AD.
0:54:26 > 0:54:30That makes it the second oldest geared instrument that we know of
0:54:30 > 0:54:32after the Antikythera mechanism.
0:54:32 > 0:54:36The gears in the back
0:54:36 > 0:54:40connect to this wheel which shows the phase of the moon.
0:54:40 > 0:54:43That's new Moon,
0:54:43 > 0:54:46waxing crescent...
0:54:47 > 0:54:50So it's likely that the ancient Greek knowledge of gearing
0:54:50 > 0:54:54was kept alive in the Byzantine world and then by the Arabs.
0:54:54 > 0:54:57It was reintroduced into Europe in the 13th century
0:54:57 > 0:55:02when the Arab Moors came up through Spain.
0:55:02 > 0:55:04Then, during the Renaissance, in the 14th century,
0:55:04 > 0:55:08highly sophisticated gear trains suddenly appeared in clocks
0:55:08 > 0:55:13all over central Europe. They all used the complex gears
0:55:13 > 0:55:16found in the Antikythera mechanism.
0:55:16 > 0:55:19The original mechanisms coming from Archimedes' workshop
0:55:19 > 0:55:21are likely to have been much larger.
0:55:21 > 0:55:24But as the Greek engineers grew more confident,
0:55:24 > 0:55:28over several generations they were able to minimise their technology.
0:55:28 > 0:55:30And bring it down to the size of a box.
0:55:30 > 0:55:34And that box was almost certainly the most prized object
0:55:34 > 0:55:37on the Antikythera treasure ship.
0:55:37 > 0:55:41The Antikythera mechanism was small, light and portable.
0:55:41 > 0:55:45They'd managed to cram nearly all their knowledge of astronomy
0:55:45 > 0:55:47into this small geared device.
0:55:47 > 0:55:51It was the theory of almost everything in a box.
0:55:51 > 0:55:55Very similar to today's modern laptop computer.
0:55:55 > 0:56:00Here, we believe is the complete and intricate machine.
0:56:00 > 0:56:02On its rear face,
0:56:02 > 0:56:08Greek scientists of 2,000 years ago fashioned a computer mechanism
0:56:08 > 0:56:11that displayed a calendar that followed the moon,
0:56:11 > 0:56:14that predicted eclipses, while on the front,
0:56:14 > 0:56:18they reproduced the universe as they understood it,
0:56:18 > 0:56:21with the five planets, the sun and the moon
0:56:21 > 0:56:25performing the complicated steps of their dance through the heavens.
0:56:27 > 0:56:29Here was Greek genius at its height.
0:56:29 > 0:56:33The great and divine cosmos
0:56:33 > 0:56:37represented through mechanism by scientists who wished to show that
0:56:37 > 0:56:42there was no mathematical challenge beyond their abilities.
0:56:42 > 0:56:45We know that this society was the birthplace of the art,
0:56:45 > 0:56:50architecture and culture that is the foundation of our modern world.
0:56:50 > 0:56:54Now, we also know that it was the cradle of advanced technology.
0:56:56 > 0:57:00Derek de Solla Price, who pioneered the early research
0:57:00 > 0:57:03on the mechanism, said this...
0:57:03 > 0:57:07"It's a bit frightening to know that just before
0:57:07 > 0:57:10"the fall of their great civilisation,
0:57:10 > 0:57:13"the ancient Greeks had come so close to our own age,
0:57:13 > 0:57:18"not only in their thought but also in their scientific technology."
0:57:21 > 0:57:25But, if it hadn't been for two storms in the Mediterranean,
0:57:25 > 0:57:28we might never have known about this mechanical wonder.
0:57:29 > 0:57:33The first storm, around 70 BC,
0:57:33 > 0:57:36sunk an overloaded Roman trading ship
0:57:36 > 0:57:39carrying the precious mechanism.
0:57:43 > 0:57:48Then, in 1900, another storm drove a team of sponge divers
0:57:48 > 0:57:52to shelter off the island of Antikythera.
0:57:52 > 0:57:56Without these two events, the most important scientific discovery
0:57:56 > 0:58:02to emerge from ancient Greece might have been lost for ever.
0:58:34 > 0:58:37Subtitles by Red Bee Media Ltd