This process is broken down into seven layers; Application Layer, Presentation Layer, Session Layer, Transport Layer, Network Layer, Data Link Layer, and Physical Layer. When a person communicates to another person on a network the information passes through these layers.
Ptolemy was an astronomer and mathematician. He believed that the Earth was the center of the Universe. The word for earth in Greek is geo, so we call this idea a geocentric theory.
It wasn't until he lay on his deathbed at the age of 70 that Copernicus published his book, De Revolutionibus Orbium Coelestium (On the Revolutions of the Heavenly Spheres). In it, Copernicus established that the planets orbited the sun rather than the Earth. He lay out his model of the solar system and the path of the planets. Refining the work. Although Copernicus' model changed the layout of the universe, it still had its faults.