Ibn Al-Haytham is one of the most famous physicists who discovered many laws and theories in physics; especially in optics. His one of the most notable work proves that the human eyes see because of light falling on the eyes. The previous concept was that eyes emit certain radiations which when hit an object, the eye can see it. Due to many contributions to optics, he is recognized as the father of modern optics.
Ibn Al-Haytham, also called Alhazen, belongs to an Arabic family that started to live in Basra (now in Iraq). He was born in the year 965 during the Golden Era of Muslims (or the Dark Age of Europe). He got his education from the teacher of Basra on mathematics, physics, astronomy, and Islamic religion. At an early age, he became very famous due to his expertise in applied mathematics.
After some time, Ibn Al-Haytham claimed that he can regulate the water flow of the River Nile and was invited by the Caliph (head of the Muslim state) to do this job. When he analyzed several designs for water regulation, he found that it is not practical to regulate the Nile. So, he had to flee from the caliph due to strong aggression from him. Ibn Al-Haytham had to hide from the caliph until the caliph died, but during that time he also continued his research work.
Ibn Al-Haytham spent last years of his life in Cairo, Egypt, where he also wrote a famous book on optics, called Kitab-al-Manazir – means the Book of Optics. He also wrote many other books and died at the age of 75 in 1040.
Discoveries and Contributions
Ibn Al-Haytham wrote many books on astronomy, physics, and mathematics. Among these books, the most famous book is the Book of Optics. Some of his contributions are:
- Optics – The Book of Optics that he wrote to discuss the principles and working of light had seven volumes. He researched working of light and wrote about it in the book for ten years. The book was translated into many languages and got huge In his book, he described how our eye sees and disproved many old concepts of Ptolemy and Euclid. Also, he proved that light travel in straight lines. He described every principle in his book on the basis of experimental observations.
- Camera Obscura (Pinhole Camera)
Ibn Al-Haytham invented a working model of camera obscura that worked on the principles of light. This camera constructed the projection of objects when light from objects entered in the hole of the camera. The entered light then projected the inverted image of the actual object inside the camera. Ibn Al-Haytham was also successful in projecting the solar eclipse in his camera.
- Mathematics – Ibn Al-Haytham was also a famous mathematician who provided a link between geometry and algebra. He also developed a mathematical formula for finding the sum of the first 100 number of Natural Set.
- Ibn Al-Haytham suggested that the atmosphere of the Earth is not infinite in space but it is only around 40 kilometers high. Today, we know that around 90% of the atmosphere is below the altitude of 10 kilometers; this layer is called troposphere. He found this fact by studying the light and motion of the sun.
- Ibn Al-Haytham wrote around 96 books in various field, out of which only 55 have survived to this date.