Discovery and exploration of the Solar System that moved through the sky. Although the Greek philosopher Aristarchus of Samos had speculated on a heliocentric reordering of the cosmos, Nicolaus Copernicus in the 16th century developed a mathematically predictive heliocentric system. His 17th-century successors, Galileo Galilei, Johannes Kepler, and Isaac Newton, developed a modern understanding of physics that led to the gradual acceptance of the idea that Earth moves around the Sun and that the planets are governed by the same physical laws that govern Earth. In more recent times, this led to the investigation of geological phenomena such as mountains and craters and seasonal meteorological phenomena such
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