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.
Nicolaus Copernicus (1473-1543) developed a heliocentric model of the universe and in the process initiated the Scientific Revolution. In his model, Copernicus maintained that Earth was not the center of the universe. Instead, Copernicus believed that Earth and the other planets revolved around the Sun.