Al-Khwarizmi’s contribution to astronomy and geography


Noor Israr examines the unique contribution of an Islamic polyglot

High intellect

The current emphasis on astronomical research is well-served by vast improvements in tools such as exceptional telescopes and other related techniques but it must be remembered that the modern advancements have been based on the efforts of exceptional intellects that laid the basis of the curiosity surrounding our universe. Al-Khwarizmi was such a towering intellect that provided plenty of foundation for further research and development in related scientific fields.

Hailing from the city of Kath in Khwarizm, parts of whom now come in the territories of Uzbekistan and Tajikistan, he served three Muslim Caliphs: al-Ma′mun (813-833), al-Mu′tasim (833-842) and al-Wathiq (842-847). He was an important part of Caliph Haroon Rashid’s House of Wisdom based in Baghdad and was generally instrumental there. His intellectual contributions were greatly valued during his times and he was well-revered by his contemporaries.

His major astronomical work known as Zij al-Sind-Hind was based primarily on Persian and Hindu astronomical sources and to some extent on Greek texts. It is known that the original tables in his Zij employed the Persian solar year and date of origin corresponding to the era of Yazdegerd III 632 CE. The Indian text on which al-Khwarizmi had based his treatise was one that had been given to the court in Baghdad around 770 CE as a gift from an Indian political mission. The Arabic connection with the subcontinent has already been restored and exchange of ideas had begun to take place.

The original Arabic version of Zij al-Sind-Hind was lost but a Latin translation that has survived in its entirety indicates that the original text consisted of 37 chapters and 116 tables containing astronomical and astrological calculations as well as detailed data on the sun and the moon and other celestial bodies. It also encompassed tables of solar and lunar eclipse and parallax as well as tables for trigonometric functions such as sines, cosine and tangents. Al-Khwarizmi’s astronomical work marked the turning point in the Islamic astronomy. Hitherto, Muslim astronomers had been translating works of others and learning already discovered knowledge but Al-Khwarizmi not only expounded extensively the works of ancient astronomers but also undertook his own research.

The map

As a signal service to Muslim contribution to science and technology and to earn immortality for himself, he developed a method to calculate the time of visibility of the new moon, indicating the beginning of the month of Ramadan. Geographical Works from among al-Khwarizmi’s geographical works two are in particular worth mentioning, one is “The Image of the Earth” and the other “The World Map of al-Ma′mun”. “The Image of the Earth” was re-discovered in 1875 by a German specialist whose cover attributed the work to al-Khwarizmi.

The Italian scholar Carlo Alfonso Nallino was the first to recognize in it al-Khwarizmi’s work on geography commissioned by Caliph al-Ma′mun. As it turned out “The Image of the Earth”, a major work in the field of geography in its own right was based on Geographike Hyphegesis put forward by Ptolemy somewhere around 150 CE. The first extensive use of Ptolemy’s work is known to be undertaken by al-Khwarizmi in his work, Kitab Surat al-Arḍ. In this work, al-Khwarizmi produces an elaboration of Ptolemy’s material made with liberties taken to make it more acceptable to Muslim thought.

Al-Khwarizmi, however, not only revised Ptolemy’s views, but also made some considerable alterations in his Geography in that he improved or corrected Ptolemy’s data with more accurate values for sites in Africa, Asia and the Middle East. Based on his own findings, al-Khwarizmi provided better values for the length of the Mediterranean Sea than Ptolemy. Al-Khwarizmi’s “The Image of the Earth,” which was finished in 833 CE, provided the latitudes and longitudes of more than 2,400 sites in the known world, including oceans, seas, rivers, mountains, islands and cities as well as other geographical features, in particular in the Islamic world. This is easily comprehensible when one takes into consideration that availability of more knowledge to al-Khwarizmi therefore his work was considerably more accurate than that of Ptolemy.

An interesting aspect of “The Image of the Earth” was the classification of weather zones. Al-Khwarizmi had ordered the inhabited quarters of the world in different climates. His contribution in the field of geography is not a servile imitation of the Greek model but an elaboration of Ptolemaic material made with more independence and ability than is displayed by any European writer of that period. Caliph al-Mamun wanted his geographers to create a world map that accurately depicted the shape of the world which would enable him to recognize countries and regions conquered by the Muslims. Al-Khwarizmi cooperated with a team of geographers to create a map of the known world to be called “The World Map of al-Ma′mun”.

Noor Israr has a discerning taste in music and he is a trained singer


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