Abu Raihan al-Biruni: Béda antarrépisi

{{quote|"Rotation of the earth would in no way invalidate astronomical calculations, for all the astronomical data are as explicable in terms of the one theory as of the other. The problem is thus difficult of solution."}}

 

{{quote|"He wrote treatises on the astrolabe, the planisphere, the armillary sphere; and formulated astronomical tables for Sultan Masud. He took it for granted that the earth is round, noted “the attraction of all things towards the center of the earth,” and remarked that astronomic data can be explained as well by supposing that the earth turns daily on its axis and annually around the sun, as by the reverse hypothesis."<ref>[[Will Durant]] (1950). ''[[The Story of Civilization]] IV: The Age of Faith'', p. 239-45.</ref>}}