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Person: Al-Biruni, Abu Arrayhan Muhammad ibn Ahmad

Al-Biruni is one of the major figures of Islamic mathematics. He contributed to astronomy, mathematics, physics, medicine and history.

Mathematical Profile (Excerpt):

• Al-Biruni was born near Kath and the town were he was born is today called Biruni after the great scholar.
• Certainly by the age of seventeen al-Biruni was engaged in serious scientific work for it was in 990 that he computed the latitude of Kath by observing the maximum altitude of the sun.
• Other work which al-Biruni undertook as a young man was more theoretical.
• As well as describing his own projection of a hemisphere onto a plane, al-Biruni showed that by the age of 22 he was already extremely well read for he had studied a wide selection of map projections invented by others and he discusses them in the treatise.
• The comparatively quiet life that al-Biruni led up to this point was to come to a sudden end.
• The end of the 10th century and beginning of the 11th century was a period of great unrest in the Islamic world and there were civil wars in the region in which al-Biruni was living.
• Another kingdom which was rapidly rising in influence was the Ghaznavids whose capital was at Ghazna in Afghanistan, a kingdom which was to play a major role in al-Biruni's life.
• Al-Biruni fled at the outbreak of the civil war but it is less clear what happened to his teacher Abu Nasr Mansur at this stage.
• Al-Khujandi discussed these observations, and his large sextant, with al-Biruni who later reported on them in his Tahdid where he claimed that the aperture of the sextant settled by about one span in the course of al-Khujandi's observations due to the weight of the instrument.
• Al-Biruni is almost certainly correct in pinpointing the cause of al-Khujandi's errors.
• Since al-Khujandi died in 1000, we can be fairly certain that al-Biruni spent part of the time between 995 and 997 at Rayy.
• We know certain dates in al-Biruni's life with certainty for he describes astronomical events in his works which allow accurate dates and places to be determined.
• The eclipse was an event that was also visible in Baghdad and al-Biruni had arranged with Abu'l-Wafa to observe it there.
• We know that al-Biruni moved around frequently during this period for by 1000 he was at Gurgan being supported by Qabus, the ruler of the Ziyarid state.
• We should record that in the Chronology al-Biruni refers to seven earlier works which he had written: one on the decimal system, one on the astrolabe, one on astronomical observations, three on astrology, and two on history.
• By 4 June 1004 al-Biruni was back in his homeland, for on that day he observed another eclipse of the moon from Jurjaniyya.
• By 1004 Abu'l Abbas Ma'mun was ruler and he provided generous support for al-Biruni's scientific work.
• Not only did al-Biruni work there but Abu Nasr Mansur, his former teacher also worked there, allowing the pair to renew their collaboration.
• With Abu'l Abbas Ma'mun's support al-Biruni built an instrument at Jurjaniyya to observe solar meridian transits and he made 15 such observations with the instrument between 7 June 1016 and 7 December 1016.
• Wars in the region were to disrupt the scientific work of al-Biruni and Abu Nasr Mansur and eventually both left Khwarazm in about 1017.
• Both al-Biruni and Abu Nasr Mansur left with the victorious Mahmud, perhaps as his prisoners.
• There follows a strange period during which there is evidence in al-Biruni's own writings that he suffered great hardships but he also seems to have been supported by Mahmud for some scientific work.
• Some reports that Mahmud was cruel to al-Biruni may have some basis despite the limited patronage al-Biruni received from the ruler.
• Some dates and places from this period can again be deduced from descriptions of astronomical events recorded by al-Biruni.
• Between 1018 and 1020, supported by Mahmud, al-Biruni made observations from Ghazna which allowed an accurate determination of its latitude.
• The relationship between Mahmud and al-Biruni is interesting.
• It is likely that al-Biruni was essentially a prisoner of Mahmud and was not free to leave.
• However Mahmud's military excursions into India meant that al-Biruni was taken to that country, and there can have been few experiences that al-Biruni would have enjoyed more.
• He may have wished for better treatment from Mahmud but al-Biruni's scientific work certainly benefited.
• Al-Biruni seems only to have been in the northern parts of India, and we are uncertain how many visits he made, but observations he made there enabled him to determine the latitudes of eleven towns around the Punjab and the borders of Kashmir.
• Al-Biruni describes the religion and philosophy of India, its caste system and marriage customs.
• Al-Biruni studied Indian literature in the original, translating several Sanskrit texts into Arabic.
• Al-Biruni was amazingly well read, having knowledge of Sanskrit literature on topics such as astrology, astronomy, chronology, geography, grammar, mathematics, medicine, philosophy, religion, and weights and measures.
• Clearly al-Biruni was unsure who would succeed for he chose not to give a dedication in his India which appeared at this time.
• If al-Biruni had been a virtual prisoner before, he now seems to have become free to travel as he pleased.
• By this time al-Biruni was an old man but he continued his enormous output of scientific works right up to the time of his death.
• The total number of works produced by al-Biruni during his lifetime is impressive.
• We have mentioned some of the works above, but the range of al-Biruni's works cover essentially the whole of science at his time.
• We have mentioned al-Biruni's astronomical observations many time above.
• Al-Biruni, on the other hand, treats errors more scientifically and when he does chose some to be more reliable than others, he also gives the discarded observations.
• One of the most important of al-Biruni's many texts is Shadows which he is thought to have written around 1021.
• Important contributions to geodesy and geography were also made by al-Biruni.
• Not all, however, were measured by al-Biruni himself, some being taken from a similar table given by al-Khwarizmi.
• Al-Biruni also wrote a treatise on time-keeping, wrote several treatises on the astrolabe and describes a mechanical calendar.
• Topics in physics that were studied by al-Biruni included hydrostatics and made very accurate measurements of specific weights.
• Many of al-Biruni's ideas were worked out in discussions and arguments with other scholars.
• Al-Biruni also corresponded with al-Sijzi.
• Al-Biruni says were due to his teacher Abu Nasr Mansur.
• In contrast with the works of many others, we find out a lot about al-Biruni from his writings.
• It appears clear that, despite his many works on astrology, al-Biruni did not believe in the 'science' but used it as a means to support his serious scientific work.
• For example the Arab conquerors of Khwarazm destroyed ancient texts - what sin could be worse than that to the scholar as dedicated to learning and history as was al-Biruni.
• An indication of the sarcasm that he employed against those he saw to be foolish we give the reply that he made to a religious man who objected to the fact that an instrument which al-Biruni was showing him to determine the time for prayers had Byzantine months engraved on it.

Born 15 September 973, Kath, Khwarazm (now Kara-Kalpakskaya, Uzbekistan). Died 13 December 1048, Ghazna (now Ghazni, Afganistan).

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Tags relevant for this person:

Ancient Arab, Astronomy, Geography, Origin Uzbekistan, Special Numbers And Numerals

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References

Adapted from other CC BY-SA 4.0 Sources:

1. O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive