Science and Islam. 3. The power of doubt.

Jim Al-Khalili investigates how astronomy has been in the forefront of scientific discovery. Al-Khlalili visits Padua in Italy where Dr Luisa Pigatto shows him a book by Copernicus in which he credited the observations of a 9th Century Arabic scholar, al-Battani (Abū Abd Allāh Muḥammad ibn Jābir ibn Sinān al-Raqqī al-Ḥarrānī aṣ-Ṣābiʼ al-Battānī). It seems that Copernicus was familiar with other scholars such as Nasir Al-Din al-Tusi (Muhammad ibn Muhammad ibn al-Hassan al-Tūsī from which we get the Tusi's couple) and he was familiar with the work of a 14th Century Arabic scholar according to George Saliba. In Damascus Al-Khalili visits one of the oldest mosques which had a sundial rumoured to have been removed. Together with a researcher, Dr Rim Turkmani, they discover the sundial on the roof hidden from view; the importance of measuring time accurately for the call to prayer is important in Islamic worship. Turkmani is an astrophysicist and specialist in Medieval astronomy. Al-Battani probably used an armillary and referring to a Greek book written hundreds of years before, he accurately measured the length of the Earth year by comparing data he observed with that written before. He also measured the Earth's tilt and published his observations; this led al-Battani and other astronomers to critique the work of Ptolemy, a Greek astronomer based in Alexandria who idealised the movements of the planets mathematically. When the work of the Greeks was called into doubt, ibn al-Haytham born 965 AD, revisited Ptolemy's theory and disproved it. Thereafter, astronomers were more cautious in their conclusions drawn from mathematics and observations. In Alamut Castle (the centre of the Ismai'lis movement), Al-Khalili investigates a new archaeological excavation, where al-Tusi worked and disproved Ptolemy's work. However, Mongol armies invaded and at 1255 they reached Alamut, al-Tusi negotiated with the invading army and asked them to build him an observatory at Rasad Khaneh. They built him a giant metal quadrant from which more measurements could be made. Back in Padua, where Copernicus was one of many scientists who began the Renaissance. Al-Khalili travels to Venice where the city had a complex relationship with trade in goods, people and ideas and the Arab world. Arabic coffee culture entered the West. Books such as that on algebra, astronomical observations and books on medicine travelled to the West. Dr Angela Nuovo discovered the oldest printed copy of the Qu'ran; there are many errors as Arabic was too difficult to reproduce in moveable type. The printing press was not adopted by the Arab World; therefore there was not the acceleration in knowledge seen in the Western World. The decline of the Islamic Empire came on several fronts; from the Mongols and the Christians. Many books were destroyed, with the exception of some books on medicine. In 1492, when Christopher Columbus discovered America, this was the watershed moment which diverted wealth away from the Islamic World. Al-Khalili suggests that Western Colonialism was the reason why Arabic scholars were considered to be inferior. In contemporary Tehran, groundbreaking stem cell research is happening which disproves that science is non-existent in the Arab World. Simon Schaffer is one of the researchers who contributes.