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
Bodhisattvas of the Earth more references to the Lotus Sutra in his commentaries than any other sutras. His commentaries focused primarily on the 15th (Emerging from the Earth) and 16th (Life Span) Chapters of the Lotus Sutra. Dōgen made numerous speculations about the significance of the bodhisattvas who emerged from the underground. As conceived by Dōgen, the stories of the underground bodhisattvas and the Buddha's inconceivable life-span serve as a fundamental shift in the development of East Asian Mahayana understanding of Buddhahood, an immediate attainment based on fundamental awakening rather than an achievement based on lifetimes of arduous practice. This can be conceived as