Beruniy’s Theory of Shadows

Beruniy’s Theory of Shadows Preface The great encyclopedic of the Middle Ages Abu Raihon Muhammad ibn Ahmad al-Beruniy was born on the 3rd of Zulhijja month in 362 hijra year (September 4, in 973) in the capital of South Khorezm - the Kat (close to Beruniy). He had a great capability to science from his very early years. He was taught by the outstanding scholar Abu Nasr Mansur ibn Irok, who had been famous with the pseudonym “Ptolemy” at that time. Abu Nasr ibn Irok devoted 12 of his works in the field of astrology, geometry and mathematics to Abu Rayhon Beruniy which meant respect and admitted his disciples erudition. In 995 the Amir of Gurganj Mamun the 1st ibn Muhammad Siavushiy occupied the Kat, which was the last fortress of Afrighians’ dynasty, and declared

himself the king of United Khorezm. Due to restless situation in Khorezm Beruniy had to leave home land at the age of 22. He lived in towns like Gurgan and Rai in Iran, where he became acquainted with the famous scientist Abu Mahmud Khujandiy, as well as he established relations with Ibn Sino through correspondence and exchanged opinions with him regarding some scientific problems. In 998 after the death of Mamun the 1st Ali Mamun ascended the throne and the political situation became more stable in Khorezm. Ali ibn Mamun was a man of science, culture and education. He charged the supervisor of Beruniy Abu Nasr ibn Irok to gather the scholars in the palace and to create conditions for scientific discussions. Approximately at the end of 1003 and at the beginning of 1004 according

to ibn Irok’s invitation Beruniy returned to Gurganj and his prosperious scientific period began. He managed the Mamun Academy, prepared disciples and wrote research works in various domains of science. Abu Raihon Beruniy authored about 152 scientific works, but only 30 of them have been passed to present generation. Beruniy’s scientific activity was polyhedral with mathematics, physics, mineralogy, ethnography and history remained his main focus. His works consisting of 11 books “The Konuniy Masudiy”, “Geodesy”, “Mineralogy”, “The Monuments left by the Ancient People” (devoted to ethnography) and “Hindiston” have been used as a manual for many centuries and even presently scientists are using them in their investigations. This brochure is a pearl of

Beruniy’s activity, which concerns geometry. In this booklette together with introducing some of the Beruniy’s mathematical investigations, discussions, some commentaries are also given. Unlike his forerunners Beruniy had a capability of thinking logically, reflecting the importance of chosen problem correctly and finding out a simple form of expression for his ideas. Beruniy’s above-mentioned essential qualities are seen vividly in his works which are remained in the history as determining of the distance from the Earth to the Moon and the Sun, where he showed the attempts, vagueness and confusions of his forerunners, discussions about the unit of measurement, gave vivid explanations to them and demonstrated the character of a leader in the field of natural sciences.

Beruniy lived in a socio-politically complicated period, which is related to the occupation of the town Kat, where Beruniy was born and lived, the removal of the capital to Gurganj, roving, destabilization, arrogance and corruption in the society. These feelings can be seen in the following Beruniy’s sentences and aphorisms: Though some men being in a very lower level in the science, behave themselves arrogance, even they dare to insult somebody. Somehow there is richness which turns the poorness into disgrace only” (Al-Beruniy Osan al-Bokiya). Richness can be lost but education will remain with you forever. Who hurts harmless scholar and enjoy it, he will be punished by the Allah. If the branches of evil are many, its source is bribery and ignorance. Our great ancestor