Alhazen

In the field of physical science one of the most important of the Arabian scientists was Alhazen.

That this sudden change does not occur, Alhazen explained as due to the reflection of light by the earth's atmosphere.

Like the measurements of Aristarchus and Eratosthenes, this calculation of Alhazen is simple enough in theory.

According to the calculation of Alhazen, this h, or the height of the atmosphere, represents from twenty to thirty miles.

As regards the refraction of light, the course of real inquiry was resumed in 1100 by an Arabian philosopher named Alhazen.