1011

Events in 1011 1

• 1011 – 1021 Ibn al-Haytham — Book of Optics Light travels to the eye, not from it — the birth of experimental science Between 1011 and 1021, while under house arrest in Cairo, the Iraqi scholar Ibn al-Haytham (Alhazen) wrote his seven-volume Kitab al-Manazir (Book of Optics). He proved by experiment that vision occurs because light reflects from objects into the eye — overturning a thousand-year-old belief that the eye emits light. He described accurately the anatomy of the eye, explained refraction, and invented the camera obscura. His rigorous experimental method was centuries ahead of its time and directly influenced Roger Bacon, Leonardo da Vinci, and later Kepler and Descartes.