Biruni (973–1048)

Abu ‘l-Rayhan Muhammad ibn Ahmad al-Biruni, one of the greatest Muslim astronomers, geographers, and scientists, was an advocate of empirical science and a practitioner of the experimental and comparative methods.

One of the most original and prolific medieval scientific writers in the natural sciences, al-Biruni was born in the city of Kat (now Biruni, in Uzbekistan), the ancient capital of Khorezm, south of the Aral Sea. Political history played an important role in his life and career. Biruni was a native speaker of the Khorezmian language (related to Persian), but the body of his work is in Arabic, including poetry; he also knew some Greek, Sogdian, Hebrew, and Syriac and learned Hindi and Sanskrit while residing in India. His early education was supervised by the learned emir of Khorezm, Abu Nasr Mansur ibn ‘Iraq al-Ja'di, an astronomer and mathematician. The young Biruni constructed astronomical instruments and globes, conducted astronomical observations to determine the ecliptic angles and coordinates of various towns in Khorezm, and described a solar eclipse. In the early 990s, war forced Biruni to flee to Rayy (near Tehran); in about 998, he moved to Gurgan (Jurjan), on the Caspian Sea, where his mentor was the Christian astronomer and physician Abu Sahl ‘Isa al-Masihi. In 997, he recorded in Kat an observation of a lunar eclipse for purposes of determination of the longitude. From Gurgan, Biruni engaged in correspondence with Abu ‘Ali Ibn Sina (Avicenna). During his stay in Gurgan, Biruni authored Kitab al-athar al-baqiya (The Chronology of Ancient Nations), the astronomical treatise Spherics, two books about the religious movement of the Qarmatians, and several works (now lost) on natural history, astronomy, and astrology. Altogether, Biruni is known to have authored, or have ascribed to him, about 150 works.

Image of Biruni from a 1973 stamp issued by Afghanistan

Source: Public domain.

In 1004, Biruni returned to Khorezm, dividing his time between politics and science cultivated within the circle of scholars of “Al-Ma'mun's Academy” at Urgench; this group included Avicenna and was named after the Khorezm-shah Abu ‘Ali Ma'mun (992–999). Astronomical observations conducted during this period formed the basis of Biruni's theory of the solar motion; he also wrote a history of Khorezm. In the 1017 [Page 283]attack on Khorezm by the army of Sultan Mahmud of Ghazna, Biruni and his teacher Ibn ‘Iraq were taken captive and taken to Ghazna, where he remained until his death in 1048. Biruni's appointment in Ghazna was as court astrologer; in Ghazna, Biruni composed some of his most significant works. In 1025, he completed The Geodesy, an astronomical-geodetic treatise Kitab tahdid nihayat al-amakin li-tashih masafat al-masakin, or The Determination of the Coordinates of Positions for Corrections of Distances Between Cities. In 1029, he finished Kitab al-tafhim li-awa'il sina'at al-tanjim, or The Book of Instruction in the Elements of the Art of Astrology, which contains 530 questions and answers related to astronomy, geography, chronology, and the theory of the astrolabe and goes considerably beyond the information required for astrological predictions.

From Ghazna, Biruni traveled to India, and in about 1030 he completed a monumental treatise, Kitab Tahrir ma li'l-Hind min maqula maqbula fi'l-'aql aw mardhula, sometimes called Ta'rikh al-Hind (Alberuni's India) or simply India. It contains vast and detailed historical, ethnographical, scientific, and cultural data and is distinguished by a remarkable lack of religious bias. In India, Biruni was able to measure degrees of latitude as well as determine the coordinates of many of the cities he visited. He learned about Indian astronomy and mathematics, translated several Sanskrit works into Arabic, and, in turn, translated into Sanskrit Euclid's Elements, Ptolemy's Almagest, and his own treatise on the astrolabe. Between 1035 and 1037, Biruni completed his major work, al-Qanun al-Mas'udi fi hay'at wa-l-nujum, or Encyclopedia of Astronomical Sciences, dedicated to his patron Mas'ud ibn Mahmud (1030–1040). This encyclopedic work contains the traditional (but expanded) astronomical tables compiled by his predecessors and a thorough discussion of theoretical questions of chronology, trigonometry, astronomy, and geography, with experimental arguments and mathematical proofs. Late in life, Biruni completed his Kitab al-jamahir fi ma'rifat al-jawahir (The Book of Most Comprehensive Knowledge on Precious Stones) and Kitab al-saydana fi-l-tibb (Book of Pharmacology in Medical Science).

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