1. BBC - History - Alhazen (c.965 - 1039) An illfated attempt to build a dam at Aswan forced him to fake insanity fortwelve years, but eventually he was to build the first version of the pinhole http://www.bbc.co.uk/history/historic_figures/alhazen.shtml

@import url('/includes/tbenh.css') ; Home TV Radio Talk ... A-Z Index TUESDAY 30th August 2005 Text only BBC Homepage History Homepage Topics Ancient Resources Interactive Content Reading Room Timelines Historic Figures ... History for Kids Practical History Archaeology Family History History Trails Community Messageboard Newsletter About This Site About the BBC ... Help Like this page? Send it to a friend! Alhazen (c.965 - 1039) Alhazen (full name Abu Ali al-Hasan Ibn al-Haitham) was the son of a civil servant and consequently relatively well educated. In the course of his reading he became fascinated by the flooding of the River Nile. He reasoned that constructing a dam would enable water to be stored for irrigation in the dry season, and flooding could be prevented at other times. He pitched his idea to the ruler of Egypt, Caliph al-Hakim. The Caliph was intrigued, and provided financial backing and workmen. On arrival at the dam's proposed site at Aswan, Alhazen realised that he had insufficient money, materials or labour to complete the project successfully. Not wanting to waste money, but concerned at the price he might have to pay for failure, he pretended to be insane, a pretence he was required to keep up until the Caliph died twelve years later. By the time the Caliph had died, in 1021, Alhazen was teaching in Cairo, where he lived out his life. He spent much of his time conducting experiments, of which many involved a dark room with a hole in it. He hung five lanterns outside the room, adjacent to the wall with the hole, and noticed that there were five 'lights' on the wall inside his dark room. He would then place an obstruction between one of the lanterns and the hole, and observed one of the 'lights' on the wall disappear. Furthermore the lantern, the obstruction and the hole were in a straight line.

2. Alhazen, The Islamic Scholar Known in the West as alhazen, Ibn aIHautham was born in965 A. D. in Basrah, and was educated in Basrah and Baghdad. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

3. ALHAZEN Known in the West as alhazen, Ibn alHaitham was born in 965 AD in Basrah, His catoptrics contain the important problem known as alhazen s problem. http://home.att.net/~mleary/alhazen.htm

965-1040 A.D.) Abu Ali Hasan Ibn al-Haitham was one of the most eminent physicists, whose contributions to optics and the scientific methods are outstanding. Known in the West as Alhazen, Ibn al-Haitham was born in 965 A.D. in Basrah, and was educated in Basrah and Baghdad. Thereafter, he went to Egypt, where he was asked to find ways of controlling the flood of the Nile. Being unsuccessful in this, he feigned madness until the death of Caliph al-Hakim. He also travelled to Spain and, during this period, he had ample time for his scientific pursuits, which included optics, mathematics, physics, medicine and development of scientific methods on each of which he has left several outstanding books. The Latin translation of his main work, Kitabal Manadhir, exerted a great influence upon Western science e.g. on the work of Roger Bacon and Kepler. It brought about a great progress in experimental methods. His research in catoptrics centred on spherical and parabolic mirrors and spherical aberration. He made the important observation that the ratio between the angle of incidence and refraction does not remain constant and investigated the magnifying power of a lens. His catoptrics contain the important problem known as Alhazen's problem. It comprises drawing lines from two points in the plane of a circle meeting at a point on the circumference and making equal angles with the normal at that point.This leads to an equation of the fourth degree. In his book Mizan al-Hikmah Ibn al-Haitham has discussed the density of the atmosphere and developed a relation between it and the height. He also studied atmospheric refraction. He discovered that the twilight only ceases or begins when the sun is 19 deg. below the horizon and attempted to measure the height of the atmosphere on that basis. He has also discussed the theories of attraction between masses, and it seems that he was aware of the magnitude of acceleration due to gravity.

4. Alhazen, The Islamic Scholar 21 alhazen named those lights which start out from self luminous bodies to be Primary lights. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

5. Alhazen - Wikipedia, The Free Encyclopedia alhazen Abu Ali alHasan Ibn Al-Haitham (also Ibn al Haythen), (965-1040), Works by alhazen on geometrical subjects were found in the Bibliothèque http://en.wikipedia.org/wiki/Alhazen

Wikimedia needs your help in its 21-day fund drive. See our fundraising page Over US$ 125,000 has been donated since the drive began on 19 August. Thank you for your generosity! Alhazen From Wikipedia, the free encyclopedia. Alhazen Abu Ali al-Hasan Ibn Al-Haitham (also: Ibn al Haythen ), was an Iranian Arab mathematician ; he is sometimes called al-Basri , after his birthplace. He was born at Basra , then part of Buwayhid Persia , now part of Iraq (See ), and probably died in Cairo Egypt . There is another Alhazen who translated Ptolemy 's Almagest in the 10th century. One version of his career has him summoned to Egypt by the mercurial caliph Hakim to regulate the flooding of the Nile . After his field work made him aware of the impracticability of his scheme, and fearing the caliph's anger, he feigned madness . He was kept under house arrest until Hakim's death in . During this time he wrote scores of important mathematical treatises. Alhazen was a pioneer in optics engineering and astronomy . According to Giambattista della Porta , he first explained the apparent increase in the size of the moon and sun near the horizon, although Roger Bacon gives the credit of this discovery to Ptolemy . He taught that vision does not result from the emission of rays from the eye, and wrote on the

6. ALHAZEN Known in the West as alhazen, Ibn alHaitham was born in 965 A.D. in Basrah, and was educated in Basrah and Baghdad. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

7. Molecular Expressions: Science, Optics And You - Timeline - Alhazen Born in Iraq as Abu Ali Hasan Ibn alHaitham, the great Arab physicist is moreoften known by the Latinized version of his first name, alhazen. http://www.microscopy.fsu.edu/optics/timeline/people/alhazen.html

Visit the Molecular Expressions Website Galleria Photo Gallery ... Home Alhazen Born in Iraq as Abu Ali Hasan Ibn al-Haitham, the great Arab physicist is more often known by the Latinized version of his first name, Alhazen. Although he was to eventually become a profound intellectual specializing in mathematics and optics, Alhazen's early education was geared towards religion and prepared him for a career as a minister. However, apparently unhappy in his religious pursuits, Alhazen later decided to devote himself to the study of science and became particularly intrigued by Aristotle. Many details of Alhazen's life have been lost over time and the stories that remain are often contradictory depending on the historian relating them. Nevertheless, it is generally held that Alhazen went to Egypt at some point in his life with a scheme to control the waters of the Nile. Invited to engineer the plan by al-Hakim, who was to become known as the Mad Caliph, Alhazen realized the impossibility of the feat. However, although he failed, al-Hakim rewarded him with an official government post, a gift that was not to be envied. As al-Hakim's behavior became increasingly erratic, Alhazen is believed to have feared for his life, feigning madness in order to be relieved of his position. Consequently, he was largely confined to his house until al-Hakim's death in 1021. Such a situation provided him with large amounts of free time with which he could conduct experiments and write, but he may have also been busy copying manuscripts in order to support himself.

8. Alhazen Alhazan alhazen 965 1039 BCE In Umberto Eco's The Name of the Rose , alhazen is mentioned briefly on pages 172 and 315. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

9. Al-Haytham He is often known as alhazen which is the Latinised version of his firstname alHasan . alhazen s problem, quoted near the beginning of this article, http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Al-Haytham.html

Abu Ali al-Hasan ibn al-Haytham Born: 965 in (possibly) Basra, Persia (now Iraq) Died: 1040 in (possibly) Cairo, Egypt Click the picture above to see two larger pictures Previous (Chronologically) Next Biographies Index Previous (Alphabetically) Next Main index Version for printing Ibn al-Haytham is sometimes called al-Basri, meaning from the city of Basra in Iraq, and sometimes called al-Misri, meaning that he came from Egypt. He is often known as Alhazen which is the Latinised version of his first name "al-Hasan". In particular this name occurs in the naming of the problem for which he is best remembered, namely Alhazen's problem: Given a light source and a spherical mirror, find the point on the mirror were the light will be reflected to the eye of an observer. We shall discuss this problem, and ibn al-Haytham's other work, after giving some biographical details. In contrast to our lack of knowledge of the lives of many of the Arabic mathematicians, we have quite a number of details of ibn al-Haytham's life. However, although these details are in broad agreement with each other, they do contradict each other in several ways. We must therefore try to determine which are more likely to be accurate. It is worth commenting that an autobiography written by ibn al-Haytham in 1027 survives, but it says nothing of the events his life and concentrates on his intellectual development. Since the main events that we know of in ibn al-Haytham's life involve his time in Egypt, we should set the scene regarding that country. The Fatimid political and religious dynasty took its name from Fatimah, the daughter of the Prophet Muhammad. The Fatimids headed a religious movement dedicated to taking over the whole of the political and religious world of Islam. As a consequence they refused to recognise the 'Abbasid caliphs. The Fatimid caliphs ruled North Africa and Sicily during the first half of the 10

10. Adventures In CyberSound Alhazen alhazen, Arabic (Abu Ali Hasan Ibn alHaitham) (b. c.965, Basra, Iraq d. 1039, Cairo), mathematician and physicist who made the first significant http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

11. Telegraph Article It acquired the name alhazen s problem after an Arab author, Ibn Alhaytham, It is sometimes known as alhazen s Billiards problem because it may be http://www-groups.dcs.st-and.ac.uk/~history/Obits2/Al-Haytham_Telegraph.html

Alhazen's Problem Don solves the last puzzle left by ancient Greeks An Oxford don has solved a classical mathematical riddle, one that first mystified the Greeks more than 1,800 years ago. The work by Dr Peter Neumann marks the solution of the last great problem of classical geometry. The solution by the Queen's College fellow to why the Greeks were unable to tackle the apparently simple geometrical problem using the methods available to them at the time has been submitted to the American Mathematical Monthly for publication. The problem was first formulated by Ptolemy in AD 150, the celebrated Alexandrian astronomer and mathematician, and asks for a method to find the point on a spherical mirror where a ray of light is reflected from a source to an observer. "It's just one of those quirky problems that had been left over," Dr Neumann told the Oxford University Gazette. "I cannot claim too much but I am pleased to have solved it." Dr Neumann has wrestled with it for almost a year, first encountering the problem when his mathematician wife, Sylvia, heard it described by Anne Watson at an Open University summer school. "At the time I thought I could solve it," Dr Neumann said. He was discouraged by his first attempt at solving the problem, although he became interested again after he was told its "long and rather rich history" by Dr John Smith, the head of mathematics at Winchester College. It acquired the name Alhazen's problem after an Arab author, Ibn Al-haytham, who treated it extensively in a fundamental work on optics written 1,000 years ago.

12. BBC - History - Alhazen (c.965 - 1039) alhazen (c.965 1039) http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

13. Malaspina Great Books - Alhazen (Ibn Al-Haytham) (965) He is to be distinguished from another alhazen who translated Ptolemy s Almagestin the alhazen was, nevertheless, a diligent and successful student, http://www.malaspina.com/site/person_69.asp

Biography and Research Links: Please wait for Page to Load or Alhazen (965-1040)

14. Al-Haitham (Alhazen), 965-1040 C.E. ABU ALI HASAN IBN ALHAITHAM (alhazen) (965 - 1040 C.E.) by Dr. A. Zahoor Click here to proceed http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

15. Alhazen (ca. 965-1039) -- From Eric Weisstein's World Of Scientific Biography Unlike Aristotle, alhazen held the correct view that objects were seen by reflectedlight, and not by light emanating from the eye. http://scienceworld.wolfram.com/biography/Alhazen.html

Branch of Science Physicists Nationality Arab Alhazen (ca. 965-1039) Arabic name: Abu-'Ali Al-Hasan Ibn Al-Haytham. Arab physicist who did extensive work on optics, studying lenses reflection and refraction Unlike Aristotle , Alhazen held the correct view that objects were seen by reflected light, and not by light emanating from the eye. Additional biographies: Bonn

16. ALHAZEN (965-1040 AD) ABU ALI HASAN IBN ALHAITHAM (alhazen) (965 - 1040 AD) by Dr. A. Zahoor (source http//home.att.net/~mleary/alhazen.htm. .. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

17. Al-Haitham (Alhazen), 965-1040 C.E. Father of modern Optics. First to describe accurately various parts of the eyeand the process of vision. Contradicted Ptolemy s and Euclid s theory of http://www.cyberistan.org/islamic/haitham.html

ABU ALI HASAN IBN AL-HAITHAM (ALHAZEN) (965 - 1040 C.E.) by Dr. A. Zahoor Biography Available in the E-Book

18. Alhazen - Wikipedia, The Free Encyclopedia alhazen Abu Ali alHasan Ibn Al-Haitham, (965-1040) was a Arab Muslim mathematician; he is sometimes called al-Basri, after his birthplace. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

19. Adventures In CyberSound Alhazen An online, academic work that will research the history of radio and the relatedmedia services of telegraphy, telephony, facsimile, television, http://www.acmi.net.au/AIC/ALHAZEN_BIO.html

20. Al-Haytham Lunar features Crater alhazen Obituaries, etc. The Telegraph (The solution of alhazen's problem) Other Web sites http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

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