WORLD HISTORY

Detailed explanation-1: -Ptolemaic system, also called geocentric system or geocentric model, mathematical model of the universe formulated by the Alexandrian astronomer and mathematician Ptolemy about 150 CE and recorded by him in his Almagest and Planetary Hypotheses.

Detailed explanation-2: -The idea was simple. Earth was stationary at the center and the Sun, Moon, and other planets all moved around Earth. Each object was fixed to a spinning crystalline sphere. The stars were all fixed to an outermost sphere and were also carried around the Earth in circular orbits.

Detailed explanation-3: -The ancient Greeks were the first to suggest (opens in new tab) a geocentric view of the universe. According to NASA (opens in new tab), Eudoxus was the first to create a model of the geocentric universe around 380 BCE.

Detailed explanation-4: -Ptolemy placed the Earth at the centre of his geocentric model. Using the data he had, Ptolemy thought that the universe was a set of nested spheres surrounding the Earth. He believed that the Moon was orbiting on a sphere closest to the Earth, followed by Mercury, then Venus and then the Sun.