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 Ibn al-Haitham 965-1040CE

Mathematician, astronomer, optician, physicist and Father of Optics 

Abu Ali al-Hasan ibn al-Haitham known to the west as Alhazen was born in 965 CE in Basra (Iraq). He is sometimes known as Al-Basri referring to his birth place.He received his education in Basra and Baghdad and later traveled to Egypt and Spain.

Ibn al-Haitham’s contributions to scientific methods were outstanding, and is known as the “Father of optics” through his extensive contributions in the field of optics. He was also one of the most eminent physicist’s who ever lived.

On one account of Ibn al-Haitham’s career, he was summoned to Egypt by thecaliph Hakim to regulate the flooding of the River Nile. After his work made him aware that the task was impractical, he feared the caliph’s anger and feigned (pretended) madness, while being kept under house arrest. During this time he wrote very many important mathematical articles.During Ibn al-Haitham’s time in Spain-where he spent most of his life- he contributed most to the field’s of mathematics, physics, medicine, scientific methods and especially optics. 

Ibn al-Haitham’s Work 

Ibn al-Haitham conducted experiments on the movement of light and colours, optical illusions and reflections. He also examined what happens when light passes through one transparent medium (air and water) into another medium (this is called refraction) and discovered the laws of refraction.    

Ibn al-Haitham also carried out the first experimentson the dispersion of light into its seven constituent colours, when the light passes through a prism. This was later discovered by Isaac Newton who normally takes all the credit for this magnificent discovery.In Ibn al-Haitham’s research in catoptrics (it is concerned with the objects to see something with e.g. magnifying glass) he focused on spherical and parabolic mirrors (a mirror looking like a rugby ball) and spherical aberration (the non convergence of rays).He made the important discovery and observation that the ratio between the angle of incidence and refraction does not remain constant. His catoptrics contains 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. He also solved the shape of an aplantic surface for reflection.                                                    

In Ibn al-Haitham’s experiments with spherical segments (glass vessels filled with water), he came very close to discovering the theory of magnifying lenses (the magnifying glass and how it works). This theory was developed in Italy three centuries later, and it took another three centuries before the law of sines was proposed by Snell and Descartes. In one of Ibn al-Haitham’s books, Kitab-al-Manazir he had written what the colours of the sunset were. He also dealt with the various physical phenomena like rainbows, eclipses, and shadows and speculated on the physical nature of light.                                                                    

All the medieval and western writers on optics like Roger Bacon and Pole Witelo (Vitellio) based their work on Ibn al-Haitham’s book the `Opticae Thesaurus`. Ibn al-Haitham’s work also influenced Leonardo da Vinci and Johann Kepler. Ibn al-Haitham was the first to describe accurately different parts of the eye and gave a scientific explanation to the process of vision. He contradicted Ptolemy’s and Euclid’s theory that the eye sends out visual rays to the object looked at while Ibn al-Haitham’s theory said that the object looked at sends light rays to your eye. He derived this from his common observations. He gave logical arguments such as;                                                                 

• The eye is dazzled or even injured if we look at a very bright light or,
• How could a ray proceeding from our eyes reach the distant stars the instant we open them.

Ibn al-Haitham developed a well argued and logical theory about the eye.Ibn al-Haitham attempted to explain binocular vision and gave a correct explanation of why the sun and moon apparently seem increased in size near the horizon although Roger Bacon gave credit of this discovery to Ptolemy.Ibn al-Haitham deduced that the homogeneous atmosphere or there is no change in atmosphere above earth for 55 miles.        

Ibn al-Haitham is known for the   earliest use of the camera obscura and through all thisextensive research and discoveries, Ibn al-Haitham is considered as the “Father of optics”Ibn al-Haitham’s contribution to mathematics and physics is also very extensive.In maths he developed analytical geometry by establishing a link between geometry and algebra.He is also credited to have invented  the pinhole camera, but the idea was later credited to Della Porta for rediscribing how the camera works.

In physics Ibn al-Haitham studied the mechanics of the motion of the body.Ibn al-Haitham was the first to propose that the body moves perpetually (continually) unless an external force stops it or changes its direction of motion. This is the first law of motion which was later discovered by Galileo.Ibn al-Haitham discussed the theory of attraction between masses which is; Mass 1 times mass 2/(forward slash represents divide) Distance between both masses squared  

It appears that Ibn al-Haitham was also aware of the magnitude of acceleration due to gravity. He also discovered that twilight stops or begins when the sun is at 19 degrees and attempted to measure the height of the atmosphere on that basis.I

bn al-Haitham’s Books 

Ibn al-Haitham wrote more than two hundred books, but sadly very few survived.His monumental treatise on optics survived through Latin translation and during the middle Ages his books on cosmology were translated into Latin, Hebrew and other European Languages.

In his book Mizan al-Hikmah (Book of the Balance of Wisdom), Ibn al-Haitham discussed the density of the atmosphere and developed a relation between it and height.   He also discussed atmospheric refraction in his book.Ibn al-Haitham also wrote commentaries on Aristotle, Galen, Euclid and Ptolemy and also wrote a book on evolution which is still useful and his ideas are still very worth reading today.

Beer and Meddler in their famous work Der Mond 1837 mention one of the surface features of the moon after Alhazen It is the name of a ring-shaped plain to the west of the hypothetical Mare Crisium in Section No. 12. Ibn al-Haitham’s extensive writings influenced many western intellectuals such as Roger Bacon, John Pecham, Witelo and Johannes Keples.       

 Works by Ibn al-Haitham on geometrical subject  were discovered in Bibliothèque nationale in Paris in 1834 by E. A. Sedillot. Other manuscripts are preserved in the Bodleian Library at Oxford and in the library of Leiden. 

Legacy 

Ibn al-Haitham left a legacy that is un-believable. In his writings you can find a clear eplaination of scientific methods developed and applied by the Muslims. His observations on physical phenomena  and their scientific theory was a major breakthrough in scientic methodology and history. His influence in physical sciences and optics in paricular is still held in high esteem and his ideas are still heralded in this new era.

Ibn al-Haitham is featured on the Iraqi 10,000  Dinars banknote issued in 2003. The asteroid 59239 Alhazen was also named in honour of Ibn al-Haitham. Also Iran’s  largest laser research facility located in the Atomic Energy Organization of Iran, its headquaters based  in Tehran is named after Ibn al-Haitham as well.

Abu Ali al-Hasan ibn al-Haitham, the father of optics, a very successful and famous mathematician, astronomer, optician and physicist died in 1040 possibly in Cairo, Egypt.