The ‘mad’ Egyptian scholar who proved Aristotle wrong

6 January 2011 | Source: Physics World


Credit: Sun and Moon Studios
Sun and Moon Studios



Ouellette brings detail to the skeletal plot of al-Haytham’s life, from the awe and intimidation felt when he was summoned by the Caliph to use his engineering prowess to overcome the annual flooding of the Nile, to his fear of punishment when he realised he had failed in his task.

Al-Haytham was only able to escape a death sentence from the notoriously brutal Caliph by pretending he had gone mad. The Caliph instead incarcerated al-Haytham, imprisoning him under house arrest to a cell. Confined and alone, it was here that al-Haytham carried out the work that was to make him famous.

In 11th-century Egypt, Aristotle’s ancient thought that visible objects and our own eyes emit rays of light to enable our vision still held.

Ouellette imagines al-Haytham lying alone in his darkened room questioning why the objects in the room are not emitting light and asking ‘Is it possible that the ancients were mistaken?’

The question providing the crux, al-Haytham was spurred into experimental action with the candles and copper in his bare room to conclude that there is no mysterious “form” that all objects emit; rather there are sources of primary light that are reflected by other objects.  



Also in the January edition:

  • Condensed-matter analogues of black holes and other cosmic phenomena may allow physicists to test ideas about quantum gravity and the early universe, as Ralf Schützhold, theoretical physicist at the University of Duisburg-Essen, and Bill Unruh, theoretical physicist at the University of British Columbia, explain.
  • Classical physics is usually enough to be able to understand the behaviour of biological molecules. But as Seth Lloyd, from the Department of Quantum Mechanical Engineering at the Massachusetts Institute of Technology, describes, some photosynthetic bacteria exploit weird quantum-mechanical effects to convert harvested light into chemical energy.

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