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.
Astronomer Nicolaus Copernicus was instrumental in establishing the concept of a heliocentric solar system, in which the sun, rather than the earth, is the center of the solar system. People Nostalgia