History of physics to simplify their production. In heliocentric models of the Solar system, the Earth orbits the Sun along with other bodies in Earth's galaxy, a contradiction according to the Greek-Egyptian astronomer Ptolemy (2nd century CE; see above), whose system placed the Earth at the center of the Universe and had been accepted for over 1,400 years. The Greek astronomer Aristarchus of Samos (c.310 – c.230 BCE) had suggested that the Earth revolves around the Sun, but Copernicus' reasoning led to lasting general acceptance of this "revolutionary" idea. Copernicus' book presenting the theory ("De revolutionibus orbium coelestium", "On the Revolutions of the
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