Spherical Earth

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The concept of a spherical Earth dates back to around the 6th century BCE in ancient Greek philosophy. It remained a matter of philosophical speculation until the 3rd century BCE when Hellenistic astronomy established the spherical shape of the earth as a physical given.The concept of a spherical Earth displaced earlier beliefs in a flat Earth: In early Mesopotamian thought, the world was portrayed as a flat disk floating in the ocean, and this forms the premise for early Greek maps like those of Anaximander and Hecataeus of Miletus. Other speculations on the shape of Earth include a seven-layered ziggurat or cosmic mountain, alluded to in the Avesta and ancient Persian writings (see seven climes).