Planetary system BC by Aristarchus of Samos, but received no support from most other ancient astronomers. "De revolutionibus orbium coelestium" by Nicolaus Copernicus, published in 1543, was the first mathematically predictive heliocentric model of a planetary system. 17th-century successors Galileo Galilei, Johannes Kepler, and Isaac Newton developed an understanding of physics which led to the gradual acceptance of the idea that the Earth moves round the Sun and that the planets are governed by the same physical laws that governed the Earth. In the 16th century the Italian philosopher Giordano Bruno, an early supporter of the Copernican theory that the Earth and
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