Ibn al-Haytham (Alhazen)

Arab polymath from Basra whose 'Book of Optics' (Kitab al-Manazir, c.1011–1021) overturned centuries of Greek emission theory, proving that vision occurs by light entering the eye rather than rays emanating from it. He conducted systematic experiments with the camera obscura, analysed refraction and reflection, and established a scientific method of hypothesis, experiment, and conclusion that prefigures modern science by six centuries.

• Lived: 965 CE – 1040 CE
• Nationality: arab
• Roles: physicist, mathematician, astronomer