Giordano Bruno motion of the stars to be an illusion caused by the rotation of the Earth on its axis; he also preserved the notion of an immobile center, but it was the Sun rather than the Earth. Copernicus also argued the Earth was a planet orbiting the Sun once every year. However he maintained the Ptolemaic hypothesis that the orbits of the planets were composed of perfect circles—deferents and epicycles—and that the stars were fixed on a stationary outer sphere. Despite the widespread publication of Copernicus' work "De revolutionibus orbium coelestium", during Bruno's time most educated Catholics subscribed to the Aristotelian
The Book of the Short Sun least "Locus: The Magazine of the Science Fiction & Fantasy Field" considered the three "Short Sun" volumes separately for annual "Best Novel" awards. The "Short Sun" of the title is an ordinary star, in contrast to the "Long Sun" of the Whorl where the narrator grew up. Most of the story takes place in a star system with two habitable planets, Blue and Green, which lend their names to the first two volumes. The Whorl of volume three's title is the generation ship setting of "Long Sun". The Tor hardcover editions (see table) were almost 1200 pages long in sum.