De revolutionibus orbium coelestium divided into six "books" (sections or parts), following closely the layout of Ptolemy's "Almagest" which it updated and replaced: Copernicus argued that the universe comprised eight spheres. The outermost consisted of motionless, fixed stars, with the Sun motionless at the center. The known planets revolved about the Sun, each in its own sphere, in the order: Mercury, Venus, Earth, Mars, Jupiter, Saturn. The Moon, however, revolved in its sphere around the Earth. What appeared to be the daily revolution of the Sun and fixed stars around the Earth was actually the Earth's daily rotation on its own axis. Copernicus adhered
The Mask of the Sun entitled "The Serpent's Star" was developed in 1983 by Ultrasoft and published by Brøderbund. The Mask of the Sun The Mask of the Sun is an graphical interactive fiction game developed by Ultrasoft and published in North America by Brøderbund and in Europe by Ariolasoft. It was released in 1982 for the Apple II, Atari 8-bit family, and Commodore 64. The hero is Mac Steele, an archaeologist who needs to find the Mask of the Sun in order to obtain an antidote to a poison that afflicts him from an artifact that he found. The game mostly takes place in