0:00:10 > 0:00:14The sun, the moon, the planets and stars
0:00:14 > 0:00:19have always fired our imaginations and fuelled our mythologies.
0:00:19 > 0:00:25And studying the heavens - astronomy - is surely the oldest scientific discipline there is.
0:00:29 > 0:00:31What's really unexpected, I guess,
0:00:31 > 0:00:35is that astronomy has repaid our interest in it over the centuries.
0:00:35 > 0:00:40Time after time it's been the place where new ideas have emerged,
0:00:40 > 0:00:42and it's often led the rest of sciences.
0:00:47 > 0:00:51I'm a Professor of Physics at the University of Surrey,
0:00:51 > 0:00:54and the ideas and theories of the great European scientists
0:00:54 > 0:01:01like Galileo, Newton and Einstein lie at the heart of my work.
0:01:01 > 0:01:02But there's another side to me.
0:01:02 > 0:01:09I'm half-Iraqi, and I'm keen to investigate stories I'd heard as a schoolboy in Baghdad
0:01:09 > 0:01:12of great astronomers from the medieval Islamic world
0:01:12 > 0:01:17whose work shaped the discoveries of these later, Western scientists.
0:01:19 > 0:01:25So, I'm going on a journey through Syria and Egypt, to the remote mountains in northern Iran,
0:01:25 > 0:01:32to discover how the work of these Islamic astronomers had dramatic and far-reaching consequences.
0:01:34 > 0:01:40There, I'll discover how they were the first to attack seemingly unshakeable Greek ideas
0:01:40 > 0:01:44about how the heavenly bodies move around the earth.
0:01:44 > 0:01:47It was Islam that paved the way
0:01:47 > 0:01:52for one of the greatest upheavals in the history of science.
0:02:20 > 0:02:23This is the University of Padua in northern Italy.
0:02:26 > 0:02:28I'm here to see incontrovertible evidence
0:02:28 > 0:02:32that one of the greatest breakthroughs in European science
0:02:32 > 0:02:36links back to the earlier work by Islamic scholars.
0:02:41 > 0:02:43Astronomer Dr Luisa Pigotti and I
0:02:43 > 0:02:47are climbing up to the 18th century observatory.
0:02:49 > 0:02:54At the top she promises to show me one of the most important books in scientific history.
0:02:56 > 0:02:59So, what do we have here?
0:02:59 > 0:03:00OK...
0:03:00 > 0:03:04This is the second edition of De Revolutionibus.
0:03:04 > 0:03:07Ah, Copernicus. Yes.
0:03:07 > 0:03:11This is De Revolutionibus Orbium Celestium,
0:03:11 > 0:03:17which was published in 1543 by the Polish astronomer Nicolaus Copernicus.
0:03:17 > 0:03:22The significance of this book is enormous.
0:03:22 > 0:03:26In it, Copernicus argues for the first time since Greek antiquity
0:03:26 > 0:03:30that all the planets, including the Earth, go around the sun.
0:03:34 > 0:03:39For thousands of years, everyone had believed a very different view -
0:03:39 > 0:03:44that the earth is static and everything - including the stars,
0:03:44 > 0:03:46sun and planets - move around it.
0:03:46 > 0:03:51And here there are...all his system, OK...?
0:03:51 > 0:03:53Oh, here we go.
0:03:53 > 0:03:57Sol. The sun in the middle.
0:03:57 > 0:04:00Yes.
0:04:00 > 0:04:01Oh, yes, there's Terra...
0:04:01 > 0:04:05With the moon. With the moon going around it. Yes.
0:04:05 > 0:04:07This is an astonishing book.
0:04:07 > 0:04:14And many historians credit it with starting the European scientific revolution.
0:04:14 > 0:04:19The first, crucial step in a journey that led to modern physics.
0:04:21 > 0:04:23Well, I agree.
0:04:23 > 0:04:25But it does seem a bit odd that one doesn't hear much
0:04:25 > 0:04:29about where Copernicus got his ideas and information.
0:04:29 > 0:04:32The impression is that they came out of nowhere.
0:04:34 > 0:04:38The beginning... The beginning is all in Arabic.
0:04:38 > 0:04:41It certainly is a real revelation to me
0:04:41 > 0:04:45that he explicitly mentions a 9th century Muslim
0:04:45 > 0:04:49for providing him with a great deal of observational data -
0:04:49 > 0:04:52an astronomer who lived in Damascus, called Al-Battani.
0:04:54 > 0:04:57Like all the great scientists of the Islamic Empire,
0:04:57 > 0:05:01Al-Battani lived in a culture without portraiture.
0:05:01 > 0:05:05All we have are later impressions of what he might have looked like.
0:05:05 > 0:05:10And here he mentions Hipparchus,
0:05:10 > 0:05:13Ptolemy and so on.
0:05:13 > 0:05:19And he started to mention what he called Machometi Aracenfis,
0:05:19 > 0:05:21he means Al-Battani.
0:05:21 > 0:05:25OK. And then this second book here... This second book is...
0:05:25 > 0:05:29We can look at the beginning in Latin... I see...
0:05:29 > 0:05:33Copernicus, in fact, made extensive use of Al-Battani's observations
0:05:33 > 0:05:37of the positions of planets, the sun, the moon and stars.
0:05:37 > 0:05:43He worked with Latin translations, similar to this one, of the Syrian astronomer's data.
0:05:43 > 0:05:45Kitab Al-Zij Al-Battani.
0:05:45 > 0:05:52So this is Al-Battani's zij, his book of star charts.
0:05:52 > 0:05:55So it has the Arabic on one side and...
0:05:55 > 0:05:58Yes. And then the Latin version.
0:05:58 > 0:06:00That's convenient.
0:06:02 > 0:06:07But certainly he had the data, the observational data, by Al-Battani.
0:06:10 > 0:06:12And Copernicus' book is full of clues
0:06:12 > 0:06:14that hints at other past sources.
0:06:17 > 0:06:22And though Al-Battani is the only Islamic astronomer Copernicus actually names,
0:06:22 > 0:06:28recent detective work has uncovered clues that Copernicus based many of his ideas
0:06:28 > 0:06:31on the work of other Islamic scholars.
0:06:31 > 0:06:36The clearest example is Copernicus's use of a mathematical idea
0:06:36 > 0:06:42devised by the 13th century Islamic astronomer Al-Tusi, called the Tusi Couple.
0:06:46 > 0:06:52Back in England, I compared a copy of Al-Tusi's Tadhkirah Al-Hay Fi'ilm Sl-hay'ah
0:06:52 > 0:06:57with another edition of Copernicus' Revolutionibus.
0:06:57 > 0:06:59In it there's a diagram of the Tusi Couple -
0:06:59 > 0:07:05and there's an almost identical diagram in Copernicus's book.
0:07:05 > 0:07:09Even down to the letters that mark the points on the circles.
0:07:09 > 0:07:13So, in Al-Tusi there is the Arabic Alif, which is A.
0:07:13 > 0:07:17There's the Baa, which is B. Gheem, over here, is the G.
0:07:17 > 0:07:21And the Dal at the centre, D.
0:07:21 > 0:07:24It's a remarkable similarity.
0:07:24 > 0:07:29Now this might just be coincidence, but it's pretty compelling evidence.
0:07:29 > 0:07:33In fact, I truly believe that Copernicus
0:07:33 > 0:07:38must have been aware of Al-Tusi's work and other Islamic astronomers.
0:07:42 > 0:07:48Further detective work also shows that Copernicus used mathematical ideas for planetary motion
0:07:48 > 0:07:53that are remarkably similar to ones developed by another Islamic astronomer,
0:07:53 > 0:07:57a 14th century Syrian called Ibn Al-Shatir.
0:07:57 > 0:08:01For some historians this cannot be coincidence.
0:08:01 > 0:08:06Copernicus, to me, I have no proof, I don't have a smoking gun.
0:08:06 > 0:08:11But to me it looked like, and by analysing his own words,
0:08:11 > 0:08:14it looks like he was working from diagrams.
0:08:14 > 0:08:21Somebody gave him a geometric diagram of what was done by Ibn Shatir to solve the problem of the moon,
0:08:21 > 0:08:25for example, to solve the problem of the upper planets,
0:08:25 > 0:08:29to solve the problem of the movement of Mercury, he had diagrams, and he was genius enough
0:08:29 > 0:08:35to be able to figure out from the diagrams what was the underlying theory behind those diagrams.
0:08:39 > 0:08:42So, far from emerging from nowhere,
0:08:42 > 0:08:46it seems Copernicus' work would be better described as
0:08:46 > 0:08:51the culmination of the preceding 500 years of Islamic astronomy.
0:08:51 > 0:08:54I wanted to investigate this story,
0:08:54 > 0:08:57find out more about those astronomers and their ideas.
0:08:59 > 0:09:03But before that, I wanted to investigate an even deeper question.
0:09:03 > 0:09:09What actually motivated medieval Islamic scholars' interest in astronomy?
0:09:23 > 0:09:25This is the Umayyad Mosque
0:09:25 > 0:09:28in the heart of the Syrian capital, Damascus,
0:09:28 > 0:09:30and is one of the oldest in the world.
0:09:35 > 0:09:38And I'm here on a kind of treasure hunt.
0:09:38 > 0:09:40Well, it says says in the books
0:09:40 > 0:09:44that there is a sundial on the top of the Arus Minaret,
0:09:44 > 0:09:46the bright minaret over there.
0:09:46 > 0:09:48So we'll see whether it is there or not...
0:09:50 > 0:09:52This is Dr Rim Turkmani,
0:09:52 > 0:09:55an astrophysicist and medieval astronomy expert
0:09:55 > 0:09:57from Imperial College London.
0:09:57 > 0:10:02And we're looking for one of the most accurate sundials made in the medieval world.
0:10:02 > 0:10:04And equally exciting for me
0:10:04 > 0:10:08is the fact that it was made by one of the Islamic astronomers
0:10:08 > 0:10:12who had so heavily influenced Copernicus, Ibn Shatir.
0:10:14 > 0:10:16Let's see...
0:10:19 > 0:10:25Officials in the mosque claim that the sundial was removed in the 19th century,
0:10:25 > 0:10:30but Rim's research suggests that an exact replica might still exist,
0:10:30 > 0:10:33high in one of the minarets, hidden from view.
0:10:33 > 0:10:36It's not quite the lost of arc of the covenant,
0:10:36 > 0:10:40but the idea of discovering a 150-year-old artefact is still quite something.
0:10:42 > 0:10:46Would you recognise anything if you...? Yeah, I need to look out of the other window, I'm sorry.
0:10:49 > 0:10:51Nope. No, it is further up...
0:10:51 > 0:10:53Yeah.
0:10:53 > 0:10:57Marking time accurately is essential to Islam.
0:10:59 > 0:11:04The Qur'an requires the faithful to pray five times a day,
0:11:04 > 0:11:06at five very precise times.
0:11:10 > 0:11:14At the exact moment of dawn, when the sun is overhead,
0:11:14 > 0:11:17in the afternoon, at sunset,
0:11:17 > 0:11:21and then again at the moment of nightfall.
0:11:21 > 0:11:28So for early Islam, an accurate sundial was an extremely important fixture in many mosques.
0:11:34 > 0:11:38That's it. That's it, I've found it! I've found it!
0:11:38 > 0:11:41Here it is, that's it, look!
0:11:41 > 0:11:46Just as described in the book. Wow! It's hidden by the pillar.
0:11:46 > 0:11:48Yeah. No wonder they didn't know that it exists here.
0:11:48 > 0:11:52It's all covered with the pigeons' filth.
0:11:52 > 0:11:56Pigeon crap. Yeah. Try that. Oh, great, thank you.
0:12:01 > 0:12:05Now, this consists of three sundials.
0:12:05 > 0:12:06The main, big one.
0:12:06 > 0:12:10And there's the northern one and the southern one.
0:12:10 > 0:12:12There is a line here for Dhuhr,
0:12:12 > 0:12:15the midday prayer, and there is one for the afternoon prayer.
0:12:17 > 0:12:21Ibn Al-Shatir had calculated the arrangement of these lines
0:12:21 > 0:12:26so that the sun dial remains accurate all through the year,
0:12:26 > 0:12:28even though length of the days change.
0:12:28 > 0:12:31They will have a timekeeper.
0:12:31 > 0:12:33You know, it's a very important job.
0:12:33 > 0:12:36Yeah. So he would sit here watching the shadow... Exactly.
0:12:36 > 0:12:42And the precise moment for prayer, he'd signal to the muezzin to start the call for prayer. Exactly.
0:12:55 > 0:12:59Ibn Al-Shatir's sundial, accurate to within minutes,
0:12:59 > 0:13:02really showed me how Islam required its scholars
0:13:02 > 0:13:06to make meticulously accurate observations of heavenly bodies.
0:13:17 > 0:13:23And I began to understand why Copernicus was so impressed by the work of his Islamic predecessors.
0:13:24 > 0:13:30They really brought standards of accuracy and precision to astronomy that were unheard of before.
0:13:32 > 0:13:36They had calculated the size of the Earth to within 1 per cent.
0:13:36 > 0:13:41And created trigonometric tables accurate to three decimal places.
0:13:44 > 0:13:49And when I met up with Rim Turkmani again on Mount Qassioun outside Damascus,
0:13:49 > 0:13:55I was to hear about the Islamic astronomer who personified accurate observation,
0:13:55 > 0:13:58the man whose astronomical tables and measurements
0:13:58 > 0:14:02Copernicus explicitly makes reference to - Al-Battani.
0:14:03 > 0:14:06Born in 858 in southern Turkey,
0:14:06 > 0:14:12Al-Battani made accurate astronomical measurement a personal obsession.
0:14:12 > 0:14:20And the story goes that Al-Battani used to observe on this mountain here in this observatory...
0:14:20 > 0:14:26Over 40 years from 877 - both here and in the town of Raqqah -
0:14:26 > 0:14:29Al-Battani's great project was to work to out,
0:14:29 > 0:14:33as accurately as possible, the length of the year.
0:14:33 > 0:14:37This is a copy of the original manuscript.
0:14:37 > 0:14:42OK. I'll show you the chapter at which he explains the length of the year, OK?
0:14:42 > 0:14:45Mm-hmm. The Chapter 27.
0:14:45 > 0:14:51So he first started by citing the ancient values of the Egyptians and the Babylonians.
0:14:51 > 0:14:52And he gives their length of the year.
0:14:55 > 0:14:57Their estimate of the year
0:14:57 > 0:15:03was 365 days, 6 hours and just over 10 minutes.
0:15:03 > 0:15:09To improve on this, Al-Battani used his ingenuity and a device like this, an armillary sphere.
0:15:09 > 0:15:14He used it to measure how the length of shadows varied over the course of the year.
0:15:14 > 0:15:17With this information he worked out the precise day
0:15:17 > 0:15:21on which it's both light and dark for exactly the same time -
0:15:21 > 0:15:23the so-called equinox.
0:15:23 > 0:15:27And he repeated his measurements over the course of 40 years.
0:15:27 > 0:15:29Now here's the clever bit.
0:15:29 > 0:15:33He then examined a Greek text that was written 700 years earlier,
0:15:33 > 0:15:38and discovered the precise day on which its author had also measured the equinox.
0:15:38 > 0:15:40He now had two vital pieces of data -
0:15:40 > 0:15:45the number of days between the two observations, and the number of years.
0:15:45 > 0:15:53He divided the first number by the second to arrive at an astonishing result -
0:15:53 > 0:15:59a year is 365 days, five hours, 46 minutes and 24 seconds.
0:15:59 > 0:16:04He gets the new number, which was only two minutes off the modern observations.
0:16:04 > 0:16:08The length of the year to an accuracy of just two minutes.
0:16:08 > 0:16:09Exactly, the one he calculated.
0:16:15 > 0:16:20What's astonishing about the accuracy of Al-Battani's measurements
0:16:20 > 0:16:21is that he had no telescope.
0:16:24 > 0:16:29He used an armillary arm, his naked eye, and devices like this - an astrolabe.
0:16:29 > 0:16:34So you move the pointer, and you move this disc with it, to point towards the North Star.
0:16:34 > 0:16:37And then these small pointers here,
0:16:37 > 0:16:41they will give you the location of the rest of the stars and the planets.
0:16:43 > 0:16:46Despite this, among his many other observations
0:16:46 > 0:16:51is an incredibly accurate figure for the Earth's tilt,
0:16:51 > 0:16:57of just under 24 degrees - about a half a degree from the figure we now know it to be.
0:16:59 > 0:17:01And he didn't stop there.
0:17:01 > 0:17:06He measured variations in the sun's diameter with such accuracy
0:17:06 > 0:17:10that it lead him to astonishing conclusion.
0:17:10 > 0:17:15This distance, the furthest point the sun reaches from the Earth during the year,
0:17:15 > 0:17:19known as its apogee, actually changes from one year to another.
0:17:22 > 0:17:26Also, his tables showing the position of the sun and moon,
0:17:26 > 0:17:31which is what Copernicus refers to some 600 years later,
0:17:31 > 0:17:34set a new standard in precision and accuracy.
0:17:37 > 0:17:42So, Al-Battani and his fellow Islamic astronomers were clearly good observers.
0:17:44 > 0:17:47But so what, you might ask.
0:17:47 > 0:17:51Well, the answer is that their observations began to suggest to them
0:17:51 > 0:17:56that the prevailing Greek theory that described how everything
0:17:56 > 0:18:00in the heavens revolved around the Earth had some serious flaws.
0:18:03 > 0:18:09This Greek tradition, which had been unquestioned for over 700 years,
0:18:09 > 0:18:15was based primarily on the work of one of the greatest astronomers of the ancient world.
0:18:19 > 0:18:22Claudius Ptolemaeus, or Ptolemy,
0:18:22 > 0:18:27was a Greek astronomer based in Alexandria in the 2nd century AD.
0:18:27 > 0:18:31He wrote one of the greatest texts in astronomy, the Alamgest,
0:18:31 > 0:18:37which was basically a distillation of all the Greek knowledge on the celestial world.
0:18:37 > 0:18:42Ptolemy believed that the sun, the moon, the planets and the stars
0:18:42 > 0:18:46all sat on crystal spheres that rotated around the Earth.
0:18:46 > 0:18:49So, the moon sits on the innermost sphere,
0:18:49 > 0:18:52followed by the sun and the planets,
0:18:52 > 0:18:56and finally, a patchwork of stars on the outermost sphere.
0:18:56 > 0:19:00So, we human beings sit at the very centre of the universe,
0:19:00 > 0:19:03with the rest of the universe rotating around us.
0:19:03 > 0:19:06But, as Ptolemy himself realised,
0:19:06 > 0:19:09there's a problem with trying to describe the heavens
0:19:09 > 0:19:14as a place of mathematically-idealised perfect spheres.
0:19:15 > 0:19:19And that is that the planets don't really play ball.
0:19:19 > 0:19:23As they move across the night sky, they change speed,
0:19:23 > 0:19:28appear to get bigger and smaller and even go back on themselves.
0:19:28 > 0:19:35Ptolemy tried to explain this away by arguing that the planets sat on small spheres called epicycles,
0:19:35 > 0:19:39which rotated around a bigger sphere called a deferent.
0:19:42 > 0:19:45This explained why they might look as though they were changing size
0:19:45 > 0:19:47and why they sometimes even changed direction.
0:19:49 > 0:19:53Unfortunately, that still didn't fit all the facts.
0:19:53 > 0:19:58It didn't easily explain why the planets appear to speed up and slow down.
0:19:58 > 0:20:03So rather desperately, Ptolemy fudged his model further
0:20:03 > 0:20:08by moving the Earth away from the centre of the deferent,
0:20:08 > 0:20:14and having the deferent rotate around an arbitrary point in space - the equant.
0:20:14 > 0:20:18But now the works of astronomers like Al-Battani
0:20:18 > 0:20:22started to strain Ptolemy's ideas to breaking point.
0:20:22 > 0:20:30Their careful observations began to suggest that even with Ptolemy's unwieldy equants and deferents,
0:20:30 > 0:20:34the actual behaviour of the heavens didn't fit the data.
0:20:34 > 0:20:38So, what do you do if you were an astronomer living in Baghdad
0:20:38 > 0:20:41and you have all these results on your table?
0:20:41 > 0:20:44The very first requirement is to say,
0:20:44 > 0:20:51this Greek tradition is not as trustworthy as it is advertised to be.
0:20:51 > 0:20:53And now of course they begin to say,
0:20:53 > 0:20:59"If the fundamental values of the astronomical measurements of the Greeks,
0:20:59 > 0:21:04"which we could double-check and we found them to be in error, what else is in error?"
0:21:04 > 0:21:10They began to question now the more basic foundational
0:21:10 > 0:21:16astronomical, cosmological foundations of the Greek tradition.
0:21:16 > 0:21:18And question they did.
0:21:23 > 0:21:30What's absolutely striking about the writings of Islamic scholars by the 9th century
0:21:30 > 0:21:36is the increasing use of the word "shukuk", which in English means "doubts".
0:21:36 > 0:21:42They showed it's sometimes necessary to doubt an idea that everyone around you believes unquestioningly.
0:21:42 > 0:21:44Islamic doubting of Greek astronomy
0:21:44 > 0:21:47began the slow process of undermining the notion
0:21:47 > 0:21:50that the Earth is at the centre of the universe.
0:21:50 > 0:21:54To doubt takes great courage and imagination,
0:21:54 > 0:22:00but if the great dialogue between Islamic and European astronomers shows anything,
0:22:00 > 0:22:04it's that doubt, or shukuk, is the engine that drives science forward.
0:22:11 > 0:22:17One of the first great shukuk scientists was called Ibn Al-Haytham.
0:22:17 > 0:22:23He was born in the Iraqi city of Basra in 965AD.
0:22:23 > 0:22:27And was among the first to argue passionately
0:22:27 > 0:22:29that scientific ideas are only valid
0:22:29 > 0:22:34if they're mathematically consistent and reflect reality.
0:22:34 > 0:22:39And when he applied his fierce, rigorous intelligence to Greek astronomy,
0:22:39 > 0:22:45he immediately spotted that there was a fundamental contradiction at its heart.
0:22:45 > 0:22:52On the one hand, Greek cosmology argued that everything in the heavens revolves around the Earth.
0:22:52 > 0:22:55On the other hand, Ptolemy, in his Almagest,
0:22:55 > 0:23:01argued that if you want to mathematically predict how the sun and planets move,
0:23:01 > 0:23:06you have to pretend that they go around an arbitrary point in space - the so-called equant.
0:23:08 > 0:23:10This is clearly a contradiction -
0:23:10 > 0:23:16the heavens can't both go around the Earth and not go around it at the same time.
0:23:16 > 0:23:20Ibn Al-Haytham hated this nonsensical contradiction.
0:23:22 > 0:23:29In the early 11th century, he wrote a paper, Al-Shukuk Ala-Batlamyus, or Doubts On Ptolemy.
0:23:29 > 0:23:33In it, he writes with barely contained frustration,
0:23:33 > 0:23:37"Ptolemy assumes an arrangement that cannot exist."
0:23:37 > 0:23:42Ibn Al-Haytham says, "That is a total absurdity. We cannot accept that."
0:23:42 > 0:23:46And furthermore he says, "It's not a slip of the tongue.
0:23:46 > 0:23:48"Ptolemy knew that it was absurd."
0:23:48 > 0:23:52And he shows us where Ptolemy himself was embarrassed by having to introduce it.
0:23:52 > 0:23:56So, he says there is a fundamental reasoning problem,
0:23:56 > 0:24:02meaning that the Greeks knew, that Ptolemy knew he was making a mistake,
0:24:02 > 0:24:04but he couldn't do any better,
0:24:04 > 0:24:09and hints, now the challenge is to do much better and hints to be able to fix this...
0:24:09 > 0:24:12That, in my explanation,
0:24:12 > 0:24:16begins to be the programme of research for all astronomers to come.
0:24:16 > 0:24:22In order to achieve that project, you had to be convinced -
0:24:22 > 0:24:24you had to be convinced -
0:24:24 > 0:24:30that it was possible to make high-precision mathematical models
0:24:30 > 0:24:34of the way in which planets and stars move,
0:24:34 > 0:24:39that would really capture how they are in the heavens.
0:24:47 > 0:24:48Ibn Al-Haytham, in effect,
0:24:48 > 0:24:52laid down the challenge for all astronomers who followed,
0:24:52 > 0:24:57which was to come up with an explanation for how the heavens move
0:24:57 > 0:25:01that is both mathematically consistent, and agrees with what we observe.
0:25:05 > 0:25:10The final answer to this would come from far-away Europe, with Copernicus and others.
0:25:10 > 0:25:14But the next and crucial breakthrough came somewhat closer.
0:25:33 > 0:25:36The top of this mountain in northern Iran
0:25:36 > 0:25:43was the adopted home of the man who was the next of Copernicus' Islamic influences,
0:25:43 > 0:25:44Nasir Al-Din Al-Tusi.
0:25:44 > 0:25:48He would succeed in rewriting Ptolemy's theory,
0:25:48 > 0:25:55which would ultimately lead to the overthrow of the geocentric view of the universe,
0:25:55 > 0:25:58and so the birth of the modern scientific age.
0:26:02 > 0:26:07This is the remote castle of Alamut,
0:26:07 > 0:26:10Al-Tusi's adopted home.
0:26:10 > 0:26:14For many years, it was the home of a Muslim sect called the Ismailis.
0:26:17 > 0:26:19It's a lovely secluded spot,
0:26:19 > 0:26:23and it was the centre of the Ismaili movement.
0:26:23 > 0:26:27It's not surprising that Al-Tusi would find a home here.
0:26:27 > 0:26:29And it wasn't just him.
0:26:29 > 0:26:31Many other scholars were gathered here
0:26:31 > 0:26:33and there seems to have been a library -
0:26:33 > 0:26:37it was a centre for learning as well as a military stronghold.
0:26:45 > 0:26:52Here, this is the main gate, northern gate of the upper castle...
0:26:54 > 0:26:59A new archaeological dig is now revealing under the castle, hewn into the living rock,
0:26:59 > 0:27:04a warren of rooms and studies, a mosque and living quarters
0:27:04 > 0:27:09for this extraordinary community of soldiers and scientists.
0:27:09 > 0:27:12This is the court of mosque,
0:27:12 > 0:27:18or centre of headquarters of castle.
0:27:21 > 0:27:25And it was within these cramped conditions
0:27:25 > 0:27:29that Al-Tusi started his masterwork of the shukuk,
0:27:29 > 0:27:31or the doubts - the Tadhkirah.
0:27:31 > 0:27:36In it he finds an answer to Ibn Al-Haytham's first challenge -
0:27:36 > 0:27:39how to eliminate Ptolemy's equant.
0:27:42 > 0:27:47Instead of a sphere rotating around an arbitrary point in space,
0:27:47 > 0:27:50Al-Tusi devised a series of two nested circles,
0:27:50 > 0:27:56which rotate around each other in such a way that they eliminate the equant.
0:27:58 > 0:28:03The nested circles became known as a Tusi Couple.
0:28:05 > 0:28:12This is the mathematical system that finds it way into Copernicus' work some 300 years later.
0:28:17 > 0:28:20Having found a solution to the equant problem,
0:28:20 > 0:28:26Al-Tusi now wanted to complete the task Ibn Al-Haytham had started 200 years earlier -
0:28:26 > 0:28:33to find a consistent mathematical description of the movement of the celestial bodies.
0:28:33 > 0:28:36But to do that he needed better data,
0:28:36 > 0:28:40which meant bigger and better equipment than he was ever going to find here at Alamut.
0:28:40 > 0:28:48And then something happened which changed Al-Tusi's life forever - the Mongols.
0:28:56 > 0:29:02Streaming in from the East, an army of Mongols led by Hulagu Khan
0:29:02 > 0:29:05marched into Iran, crushing everything before them.
0:29:08 > 0:29:15By 1255, they had reached the foothills of Alamut, intent on its destruction.
0:29:18 > 0:29:20Then, in a brilliant piece of diplomacy,
0:29:20 > 0:29:24Al-Tusi managed to both save his own skin
0:29:24 > 0:29:27and satisfy his scientific ambition.
0:29:28 > 0:29:34He visited the Mongol leader, and played on his deep astrological superstition.
0:29:37 > 0:29:43Convincing him he could tell the future if only he had new equipment, Al-Tusi persuaded the Khan
0:29:43 > 0:29:48to make him his head scientist and to build him, just a few hundred miles away,
0:29:48 > 0:29:51perched on a hilltop where the air was clear,
0:29:51 > 0:29:55the largest observatory the world had ever seen.
0:30:04 > 0:30:10This is all that remains of the Maragheh Observatory.
0:30:10 > 0:30:13The main instrument is hidden is under this protective dome.
0:30:16 > 0:30:22Al-Tusi's new astronomical centre was based around a single large building.
0:30:23 > 0:30:27Inside was an enormous metal arc,
0:30:27 > 0:30:30an armillary arm, ten metres across.
0:30:32 > 0:30:37On its circumference were marked angles in degrees and minutes.
0:30:37 > 0:30:41The scientists would line up the celestial object under study
0:30:41 > 0:30:47with a central point on the arc, and then make a reading from the markings on the arc,
0:30:47 > 0:30:51giving them the definitive, accurate position of the object in the sky.
0:30:55 > 0:30:59The building was also surrounded by smaller astronomical equipment,
0:30:59 > 0:31:02libraries, offices and accommodation.
0:31:04 > 0:31:08The observatory even had its own dedicated mosque.
0:31:15 > 0:31:20I suppose it is a little disappointing that there's not much left of the place now,
0:31:20 > 0:31:24so you really have to imagine what it must have been like back in its heyday.
0:31:24 > 0:31:27After all, what Al-Tusi built here
0:31:27 > 0:31:32was nothing less than the world's greatest observatory for 300 years.
0:31:32 > 0:31:37And like any modern-day international research institute,
0:31:37 > 0:31:43he brought together the world's greatest astronomers from as far away as Morocco and even China.
0:31:43 > 0:31:48I mean, it really must have been a great buzzing atmosphere to work here.
0:31:55 > 0:31:58With his new observatory and world-class team,
0:31:58 > 0:32:02Al-Tusi was now ready to fulfil Ibn Al-Haytham's dream -
0:32:02 > 0:32:07to try to make Ptolemy's model scientifically rigorous.
0:32:07 > 0:32:11First they attacked the mathematics.
0:32:11 > 0:32:16As well as the Tusi Couple, they invented other systems of planetary movement.
0:32:16 > 0:32:19And with these new systems, they were able to calculate
0:32:19 > 0:32:24mathematically-consistent models for many of the celestial bodies.
0:32:24 > 0:32:30Mercury, Venus, Mars, Jupiter, Saturn and the sun and moon.
0:32:38 > 0:32:45Al-Tusi and the astronomers he brought together created what became known as the Maragheh revolution,
0:32:45 > 0:32:51which was a complete paradigm shift in astronomy, overthrowing the old Ptolemaic view.
0:32:51 > 0:32:56What Islamic scholars and astronomers like Al-Tusi do
0:32:56 > 0:33:02is to organise and make sense of mathematical astronomy
0:33:02 > 0:33:05at a level of unprecedented accuracy,
0:33:05 > 0:33:09using instruments more precise than had been built before,
0:33:09 > 0:33:13over longer timescales, with predictions
0:33:13 > 0:33:17of the positions of planets and stars that no-one had previously reached -
0:33:17 > 0:33:21that at Maragheh or at Alamut
0:33:21 > 0:33:28we see, I think, genuine revolutions in the level, scale and intensity of mathematical astronomy.
0:33:35 > 0:33:37But there was still a problem.
0:33:37 > 0:33:44The new models were mathematically coherent and they dispensed with Ptolemy's unwieldy equant.
0:33:44 > 0:33:49But they still firmly placed the earth at the centre of the universe,
0:33:49 > 0:33:55and that inevitably meant that their descriptions of the heavens were intricate and complicated,
0:33:55 > 0:34:01with epicycles, deferents and couples - it was like some great cosmic gearbox.
0:34:08 > 0:34:13It would require a huge leap of imagination to make the next step in our story.
0:34:13 > 0:34:18And that next step would take place 2,000 miles from where I am now.
0:34:33 > 0:34:37In my view, the last phase of the Maragheh revolution took place
0:34:37 > 0:34:43not in Iran or anywhere in the Islamic Empire, but here in Northern Italy.
0:34:43 > 0:34:46Based on the work of Muslim scholars, places like
0:34:46 > 0:34:51the University of Padua were already starting a new scientific movement -
0:34:51 > 0:34:52the Renaissance.
0:34:56 > 0:34:59Back in Padua, where I began my journey,
0:34:59 > 0:35:05I now understand why Islamic astronomers were so important to Copernicus.
0:35:05 > 0:35:07They gave him his motivation.
0:35:08 > 0:35:15He's the first European to share Ibn Al-Haytham's deep aversion to Ptolemy's cosmology.
0:35:15 > 0:35:19And that's what makes Copernicus not the first great astronomer
0:35:19 > 0:35:23of a new European tradition, but the last of the Islamic tradition.
0:35:27 > 0:35:34As we've seen, many of the complex mathematical models Copernicus uses in his new heliocentric model,
0:35:34 > 0:35:38like the Tusi Couple, are copied from Islamic astronomers.
0:35:38 > 0:35:42But more importantly, it's Copernicus's deep desire
0:35:42 > 0:35:49to bring mathematical consistency to cosmology that he really owes to his Islamic predecessors.
0:35:51 > 0:35:57Copernicus' ideas set in motion a train of scientific revelations
0:35:57 > 0:36:02that would eventually lead to Isaac Newton and the discovery of gravity.
0:36:02 > 0:36:07In Newton's hands, Ibn Al-Haytham's dream of an astronomy with rigorous
0:36:07 > 0:36:13and coherent mathematics which agrees with experimental observation finally took place.
0:36:23 > 0:36:26But this begs two crucial questions -
0:36:26 > 0:36:30why was the great astronomical project which Islamic astronomers began
0:36:30 > 0:36:35completed in Europe and not in the Middle East?
0:36:35 > 0:36:39And how did knowledge of Islamic science get to Europe in the first place?
0:36:45 > 0:36:49The answers to these questions lie in one of the most beautiful cities on earth,
0:36:49 > 0:36:53the Queen of the Adriatic - Venice.
0:37:08 > 0:37:13Venice was founded on a swamp off the coast of Italy,
0:37:13 > 0:37:18and felt itself separate from Europe, and not bound by its laws and traditions.
0:37:18 > 0:37:22And as Shakespeare famously pointed out, the two most important aspects
0:37:22 > 0:37:30of Venice were its merchants and its longstanding links with the Arabs, or Moors.
0:37:30 > 0:37:37It was a rich and complicated relationship, sometimes based on piracy and theft.
0:37:37 > 0:37:40The story goes that in 828,
0:37:40 > 0:37:44two Venetian merchants stole the bones of a famous Christian saint
0:37:44 > 0:37:47from Venice's rival city across the water, Alexandria.
0:37:47 > 0:37:53The bones belonged to St Mark the Evangelist, and they brought them back to here to St Mark's Square.
0:37:59 > 0:38:04But without doubt, trade with the East brought to Venice great wealth
0:38:04 > 0:38:11and an exchange of ideas, customs and people, as Venice expert Vera Costantini showed me.
0:38:11 > 0:38:14So this is called the Campo dei Mori because as you can see
0:38:14 > 0:38:21at the corners, there are statues of what were called Moors.
0:38:21 > 0:38:24There's another... Yeah, there's another one with a turban.
0:38:24 > 0:38:29The beard was recommended to many Venetian merchants even when they went to the East.
0:38:29 > 0:38:33There were manuals written for Venetian merchants.
0:38:33 > 0:38:35How to blend in?
0:38:35 > 0:38:38Yes. How to be respected in the East.
0:38:41 > 0:38:45As Venetians traded more and more with their Muslim neighbours,
0:38:45 > 0:38:49the influence of Islam was more strongly felt.
0:38:51 > 0:38:54Arabic coffee culture became hugely popular.
0:38:57 > 0:38:59As did Islamic styles of architecture,
0:38:59 > 0:39:02with their characteristic arches and decorations.
0:39:06 > 0:39:09So, the next thing I want to show you is the Palace of the Camel.
0:39:09 > 0:39:15When Venetians traded in the East, the unit of measurement,
0:39:15 > 0:39:21of a load that could be loaded on a dromedary was called a carrico.
0:39:21 > 0:39:24And it was exactly the same unit of measurement
0:39:24 > 0:39:28they had in the East. And it was called yook.
0:39:28 > 0:39:30So it's not coincidence that
0:39:30 > 0:39:33they actually imported that unit of weight.
0:39:33 > 0:39:36Yes, of measurement, of weight.
0:39:39 > 0:39:44And with the Arabic trade came the Arabic books.
0:39:44 > 0:39:50The great 9th century Arabic text on algebra appeared in Latin in the 12th century.
0:39:50 > 0:39:55The same century saw the arrival of Arabic astronomical tables,
0:39:55 > 0:40:01and in the 15th century, the famous canon of medicine was first published in the West.
0:40:10 > 0:40:15And this influx of learning seems to coincide with a great historical shift.
0:40:15 > 0:40:21The engine of science begins to move west, from the Islamic world to Europe.
0:40:21 > 0:40:26That's where the great breakthroughs from the 1500s would mainly take place.
0:40:36 > 0:40:43I encountered an astonishing and very tangible symbol of this shift, and a really surprising clue
0:40:43 > 0:40:49as to why it happened, thanks to Professor Angela Nuovo, from the University of Udine.
0:40:53 > 0:40:5720 years ago, in this library on one of the islands of Venice,
0:40:57 > 0:41:03Angela discovered the only surviving version of a 500-year-old book.
0:41:03 > 0:41:07And what did it feel like? This is a big, big discovery!
0:41:07 > 0:41:10Yes, yes. It was a great emotion.
0:41:10 > 0:41:13I remember it was July, very hot, like today - even hotter.
0:41:13 > 0:41:15And I felt cold.
0:41:15 > 0:41:17Wow!
0:41:17 > 0:41:19Yes, it was a great emotion.
0:41:22 > 0:41:29What she found was the very first printed copy of Islam's holy book, the Qur'an.
0:41:38 > 0:41:45This is the first time she has seen her Qur'an since she discovered it 20 years ago.
0:41:45 > 0:41:49But it struck me as strange that world's first printed Qur'an
0:41:49 > 0:41:53was produced in Venice, and not in the Islamic world.
0:41:53 > 0:42:00And it's obvious at first glance that it was printed by people who didn't speak Arabic very well.
0:42:00 > 0:42:04HE READS ALOUD
0:42:08 > 0:42:10What strikes me is that
0:42:10 > 0:42:17it's written in what I would regard as almost childlike handwriting.
0:42:17 > 0:42:19It's clumsy.
0:42:19 > 0:42:26Yeah. Well, it's the first attempt to reproduce the handwriting in moveable types,
0:42:26 > 0:42:31and as you know, the language has an enormous amount of different sorts.
0:42:31 > 0:42:36Every letter changes according to ligatures and the position.
0:42:36 > 0:42:38Of course, so it's difficult.
0:42:38 > 0:42:41Yeah, the word meaning "for that",
0:42:41 > 0:42:49the dash should be underneath the L, but it's above it, so it says the wrong thing.
0:42:49 > 0:42:56Probably there were not people of mother language in the press.
0:42:56 > 0:43:01So there were some errors in the text, which are of course sins.
0:43:01 > 0:43:08Yes, of course, as the Qur'an, every Muslim believes it's the word of God, you can't change it.
0:43:08 > 0:43:11So when you change it, it's a sin.
0:43:11 > 0:43:14How was it first received when it was published?
0:43:14 > 0:43:18Well, yes, the hypothesis is, and I think it's true,
0:43:18 > 0:43:23that it was an enormous failure from the business point of view.
0:43:23 > 0:43:28The Muslims didn't accept the printing press for centuries,
0:43:29 > 0:43:33and probably the whole copies of this book were destroyed.
0:43:33 > 0:43:36So we don't have any other copy.
0:43:36 > 0:43:41Probably the only one that remained in the Western world is this book.
0:43:41 > 0:43:48'I felt that the failure of this printed Qur'an to catch on in the Islamic world spoke volumes.'
0:43:53 > 0:43:58800 years earlier, one reason for Islamic science's success
0:43:58 > 0:44:03had been the precision of the Arabic language - with over 70 different ways
0:44:03 > 0:44:08of writing its letters and many extra symbols to define pronunciation and meaning,
0:44:08 > 0:44:14it allowed scholars of many different lands to communicate in a single, common language.
0:44:18 > 0:44:21Now, with the arrival of the printing press,
0:44:21 > 0:44:26scientific ideas should have been able to travel even more freely.
0:44:26 > 0:44:32In the West, books printed in Latin accelerated its scientific renaissance.
0:44:32 > 0:44:37But because of its symbols and extra letters,
0:44:37 > 0:44:40Arabic was much harder to set into type than Latin,
0:44:40 > 0:44:45and so a similar acceleration in the Islamic world failed to materialize.
0:44:46 > 0:44:52I believe this rejection of the new technology - the printing press -
0:44:52 > 0:44:57marks the moment in history when Arabic science undergoes a seismic shift.
0:44:57 > 0:45:02Europe has embraced Greek and Arabic knowledge and the new technology.
0:45:02 > 0:45:07And Galileo and his ilk are poised at the cusp of the Renaissance.
0:45:07 > 0:45:11It has been a turning point both in the history
0:45:11 > 0:45:15of the Venetian printing press, who used to be extremely powerful.
0:45:15 > 0:45:18It's the limit of expansion, let's say.
0:45:18 > 0:45:24And in the history of the general and cultural relationship between the East and the West.
0:45:24 > 0:45:28As acceptation of printing would have meant
0:45:28 > 0:45:31the acceptation of the first important technology,
0:45:31 > 0:45:37so the two histories started to differ very much.
0:45:41 > 0:45:45This initial rejection of printing was one of the many reasons
0:45:45 > 0:45:50that caused science in the Islamic world to fall behind the West.
0:45:50 > 0:45:58It coincided with a host of global changes, all of which affected the way science developed.
0:46:06 > 0:46:09The first and most obvious reason for the slowdown in Islamic science
0:46:09 > 0:46:13is that the Islamic empire itself
0:46:13 > 0:46:17falls into decline from the mid-1200s.
0:46:17 > 0:46:21One reason for this is that it's under attack from all sides.
0:46:21 > 0:46:23From the east are the Mongols.
0:46:28 > 0:46:32In 1258, they invaded the capital, Baghdad, and it's said that
0:46:32 > 0:46:35the waters of the Tigris and Euphrates rivers
0:46:35 > 0:46:40ran black for days with the ink of the books they'd destroyed.
0:46:40 > 0:46:44But trouble was also brewing in the far west of the empire.
0:46:48 > 0:46:55Islamic Spain, already fragmented into separate city states, now faced a new threat -
0:46:55 > 0:47:00a united and determined onslaught from the Christian north.
0:47:03 > 0:47:07The re-conquest, as it was called, raged for hundreds of years,
0:47:07 > 0:47:12but culminated in the 15th century, when Ferdinand II and Isabella
0:47:12 > 0:47:19led an army which forced the last of the Muslims in Grenada to surrender in 1492.
0:47:19 > 0:47:21The Christians were intent
0:47:21 > 0:47:26on removing every last vestige of Islamic civilization and culture from Spain.
0:47:26 > 0:47:31In 1499, they ordered the burning in this square in Granada
0:47:31 > 0:47:34of all Arabic texts from Granada's libraries...
0:47:34 > 0:47:38except for a small number of medical texts.
0:47:38 > 0:47:42Within about 100 years, every Muslim in Spain
0:47:42 > 0:47:46had either been put to the sword, burnt at the stake or banished.
0:47:49 > 0:47:56And Christians from the east of Europe were intent on reclaiming the Holy Land -
0:47:56 > 0:47:57the Crusades.
0:47:59 > 0:48:03Bent on carving out a wholly Christian Levant
0:48:03 > 0:48:05and claiming the holy city of Jerusalem,
0:48:05 > 0:48:09the Crusaders launched a massive attack on Northern Syria.
0:48:09 > 0:48:14They quickly captured this castle and turned it into one of their strongholds.
0:48:14 > 0:48:19Then, with ruthless and missionary zeal, they marched on Jerusalem.
0:48:19 > 0:48:26And as the empire fought with its neighbours, it collapsed into warring fiefdoms.
0:48:26 > 0:48:30The Mamluks, slaves who originally belonged to the state of Egypt,
0:48:30 > 0:48:32became its leaders.
0:48:32 > 0:48:38The Bourbon Almohads ruled Morocco and Spain in the 13th century.
0:48:38 > 0:48:43And the north of Syria and Iraq splintered into a series of city states.
0:48:46 > 0:48:50But for many historians of science, the biggest single reason
0:48:50 > 0:48:56for the decline in Islamic science was a rather famous event that took place in 1492.
0:48:56 > 0:49:01That year, the entire political geography of the world
0:49:01 > 0:49:08changed dramatically when a certain Christopher Columbus arrived in the Americas.
0:49:08 > 0:49:11I explain it with the phenomena of
0:49:11 > 0:49:14the discovery of the New World in 1492.
0:49:14 > 0:49:18The immediate result is that you got immense amounts of gold and silver
0:49:18 > 0:49:23coming to the royal houses of Europe at the time and all the adventurers,
0:49:23 > 0:49:27empires and royal houses of the time were setting colonies all over the world.
0:49:27 > 0:49:31And science always follows the money.
0:49:31 > 0:49:36As the 16th and 17th centuries came and went, that money,
0:49:36 > 0:49:42power and hence scientific will, moved through Italy, Spain and onto Britain.
0:49:42 > 0:49:45By the 17th century, England, sitting at the centre
0:49:45 > 0:49:50of the lucrative Atlantic trade route, could afford big science.
0:49:50 > 0:49:54And that ultimately explains why the greatest book in world science,
0:49:54 > 0:49:57Sir Isaac Newton's Principia Mathematica,
0:49:57 > 0:50:01the book that ultimately explains the motion of the sun, moon and planets,
0:50:01 > 0:50:06was not published in Baghdad, but in London.
0:50:06 > 0:50:11It was necessary for him to have data of astonishing accuracy
0:50:11 > 0:50:15gathered from across the world.
0:50:15 > 0:50:22Global inventories of numbers, observations, positions.
0:50:22 > 0:50:28The heights of tides, the positions of comets and planets, the rate at which pendulums beat...
0:50:28 > 0:50:32It's a global project, it's big science.
0:50:32 > 0:50:37And many of those observations, many of those mathematical models
0:50:37 > 0:50:40were of course models initially developed
0:50:40 > 0:50:47by Islamic astronomers in Egypt and the Near East and Central Asia.
0:50:50 > 0:50:54But there's a final twist in the tale.
0:50:56 > 0:51:00As the wealth of the Islamic nations subsided through war,
0:51:00 > 0:51:04political and religious entrenchment and the loss of its lucrative trade,
0:51:04 > 0:51:08so its science declined.
0:51:08 > 0:51:13But what this doesn't explain is why their scientific achievements have been so forgotten.
0:51:15 > 0:51:21And that's partly because as Europeans colonised great swathes of the Middle East and Asia,
0:51:21 > 0:51:23they actively encouraged the idea
0:51:23 > 0:51:28that the civilizations they encountered were moribund and in decline.
0:51:28 > 0:51:35It seems the English and the French were uncomfortable with subjugating people
0:51:35 > 0:51:39whose knowledge and science might be as sophisticated as their own.
0:51:39 > 0:51:42So it became important to portray the Islamic world
0:51:42 > 0:51:45in a very specific way,
0:51:45 > 0:51:50namely that yes, they once were very sophisticated and had great scientists and philosophers,
0:51:50 > 0:51:52but of course now, they've fallen into decay.
0:51:52 > 0:51:59Somehow this point of view made the whole colonial enterprise seem much more palatable.
0:51:59 > 0:52:03One of the most fascinating developments, I think,
0:52:03 > 0:52:09in the history of the encounter between western Europeans and other cultures
0:52:09 > 0:52:17is a kind of shift which has got fundamental and terrible consequences
0:52:17 > 0:52:19amongst western Europeans,
0:52:19 > 0:52:25when they start to reflect on why they are superior.
0:52:25 > 0:52:31It doesn't often cross western Europeans' minds that they might not be superior to everybody else.
0:52:31 > 0:52:36For a very long time after all, western Europeans in general,
0:52:36 > 0:52:40the British, for example, supposed that their superiority lay in their religion.
0:52:40 > 0:52:46But then I think around the 1700s, we begin to see a shift.
0:52:46 > 0:52:52And the shift is from claiming that the reason for European superiority is its religion
0:52:52 > 0:52:57to the reason for European superiority is its science and technology.
0:52:59 > 0:53:04Eventually it ends up with the famous phrase, "We have the Gatling gun, and they do not."
0:53:04 > 0:53:12Europeans in that period were quite prepared to acknowledge that in ancient times,
0:53:12 > 0:53:17Islam for example had achieved great things in the sciences.
0:53:17 > 0:53:21But they weren't doing so now.
0:53:21 > 0:53:26So even recent Islamic and Sanskrit astronomy
0:53:26 > 0:53:28was imagined to be very old,
0:53:28 > 0:53:34because if it was very old, it meant that the culture the British were conquering was declining.
0:53:34 > 0:53:37And for the British, that was clearly good news.
0:53:40 > 0:53:45And some experts believe that the effect of this on Islamic scientific history
0:53:45 > 0:53:50is still felt in the Islamic world today.
0:53:50 > 0:53:54The Islamic part and the Arab part have not yet discovered their history
0:53:54 > 0:53:58because their history was obliterated intentionally
0:53:58 > 0:54:03by the colonisation period. And unfortunately when they rediscover it now,
0:54:03 > 0:54:05they are rediscovering it in bits and pieces.
0:54:09 > 0:54:14So today, for many different reasons, the great observatories
0:54:14 > 0:54:19of the medieval Islamic world are ruined husks.
0:54:19 > 0:54:23And it's true to say that most of the great scientific breakthroughs
0:54:23 > 0:54:28of the last four centuries have taken place in the West.
0:54:28 > 0:54:34But that's not to say that science has completely ground to a halt in the Islamic world.
0:54:34 > 0:54:36Now, in the 21st century,
0:54:36 > 0:54:40there are many examples of cutting-edge research being carried out.
0:54:40 > 0:54:43I've arrived at the Royan Institute here in Tehran,
0:54:43 > 0:54:46where they carry out stem cell research,
0:54:46 > 0:54:49infertility treatment and cloning research.
0:54:53 > 0:54:57I was surprised to learn that here in Iran, an Islamic state,
0:54:57 > 0:55:01potentially controversial science like genetic modification
0:55:01 > 0:55:07and cloning is condoned, even funded by a theocratic government.
0:55:07 > 0:55:10One of the uses is when a small part of the heart stops working,
0:55:10 > 0:55:13which is finally going to lead to heart failure...
0:55:13 > 0:55:19Right. So the cells from that part of the heart are actually replaced with the cells that have been cloned.
0:55:19 > 0:55:23Another use of cloning in therapeutics
0:55:23 > 0:55:29is actually creating an animal which has the medicine in their milk, for example.
0:55:29 > 0:55:35So when we drink the milk, we actually receive the medicine we need.
0:55:35 > 0:55:40Considering genetic research has many vociferous opponents in Christian communities,
0:55:40 > 0:55:43I was intrigued to see that here in Tehran,
0:55:43 > 0:55:48they have their own in-house imam to offer support and advice
0:55:48 > 0:55:51on this sometimes quite controversial research.
0:55:55 > 0:56:01TRANSLATION: We have got this medical ethic committee here in Royan Institute,
0:56:01 > 0:56:07and every project which is proposed is investigated
0:56:07 > 0:56:11in this committee, and we see different aspects of it,
0:56:11 > 0:56:15and they have got to justify the project for us.
0:56:15 > 0:56:20I'm not enough of an expert in genetics to truly assess the quality of the work here.
0:56:20 > 0:56:24But one thing I can say is how at home I felt.
0:56:24 > 0:56:28Whatever cultural and political differences we have with the Iranian state,
0:56:28 > 0:56:31inside the walls of the lab,
0:56:31 > 0:56:36it was remarkably easy to find common ground with fellow scientists.
0:56:38 > 0:56:42Nature's rules are refreshingly free of human prejudice.
0:56:42 > 0:56:48That's something the scientists of the medieval Islamic world understood and articulated so well.
0:56:51 > 0:56:56In the 9th century, Al-Khwarizmi synthesised Greek and Indian ideas
0:56:56 > 0:57:01to create a new kind of mathematics, algebra.
0:57:02 > 0:57:06The polymath Ibn Sina brought together the world's traditions
0:57:06 > 0:57:12of healthcare into one book, contributing to the creation of the subject of medicine.
0:57:12 > 0:57:15In remote Iranian mountains,
0:57:15 > 0:57:22astronomers like Al-Tusi paved the way for scientists working hundreds of years later in Western Europe.
0:57:22 > 0:57:27These scientists' quest for truth, wherever it came from,
0:57:27 > 0:57:31were summed up by the 9th century philosopher Al-Kindi, who said,
0:57:31 > 0:57:35"It is fitting for us not to be ashamed of acknowledging truth,
0:57:35 > 0:57:39"and to assimilate it from whatever source it comes to us.
0:57:39 > 0:57:42"There is nothing of higher value than truth itself.
0:57:42 > 0:57:47"It never cheapens or abases he who seeks."
0:57:52 > 0:57:56One moral emerges from this epic tale of the rise and fall
0:57:56 > 0:58:01of science in the Islamic world between the 9th and 15th centuries.
0:58:01 > 0:58:06And that is that science is the universal language of the human race.
0:58:06 > 0:58:10Decimal numbers are just as useful in India as they are in Spain.
0:58:10 > 0:58:15Star charts drawn up in Iran speak volumes to astronomers in northern Europe.
0:58:15 > 0:58:21And Newton's Principia is as true in Arabic as it is in Latin or English.
0:58:21 > 0:58:25What medieval Islamic scientists realised and articulated
0:58:25 > 0:58:31so brilliantly is that science is the common language of the human race.
0:58:31 > 0:58:34Man-made laws may vary from place to place,
0:58:34 > 0:58:38but nature's laws are true for all of us.
0:58:51 > 0:58:54Subtitles by Red Bee Media Ltd
0:58:54 > 0:58:56Email subtitling@bbc.co.uk
0:59:17 > 0:59:20When I think of the world we inhabit, everyone will think,
0:59:20 > 0:59:21"Oh, this was done digitally."
0:59:21 > 0:59:23Yeah. And it wasn't, it was done by hand
0:59:23 > 0:59:26over days and weeks and months and years.
0:59:27 > 0:59:31It was always a very, very deep love affair