sentences:  Aristarchus of Samos, in the 3rd century BCE, proposed what was, so far as is known, the first serious model of a heliocentric Solar System, having developed some Heraclides Ponticus' theories (speaking of a "revolution of the Earth on its axis" every 24 hours).Though his original text has been lost, a reference in Archimedes' book "The Sand Reckoner" ("Archimedis Syracusani Arenarius & Dimensio Circuli") describes a work in which Aristarchus advanced the heliocentric model.Archimedes wrote