Cosmology in medieval Islam empirical testing. His work thus marked a turning point in astronomy, which may be considered a "Scientific Revolution before the Renaissance". His rectified model was later adapted into a heliocentric model by Copernicus, which was mathematically achieved by reversing the direction of the last vector connecting the Earth to the Sun. In the published version of his masterwork, "De revolutionibus orbium coelestium", Copernicus also cites the theories of al-Battani and Averroes as influences. An area of active discussion in the Maragheh school, and later the Samarkand and Istanbul observatories, was the possibility of the Earth's rotation. Supporters of this theory
The Continent Makers and Other Tales of the Viagens mid-21st-century to the mid-twenty-second. Individual stories are set on spaceships traveling between planets and individual planets such as Earth, Krishna, Ganesha and Osiris (it being assumed that Terrans will have carried their penchant for naming planets after gods to other star systems). Features of the postulated future include an Earth governed by a World Federation in which Brazil has become the paramount great power, with Terran space travel monopolized by a Brazilian-dominated agency called the "Viagens Interplanetarias" ("Interplanetary Tours" in Portuguese). Interstellar travel is limited to sub-light speeds, as the author eschews such common science fiction gimmicks as hyperdrives. The