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.
9,339 Contributions. Nicolas Copernicus was an astronomer who first gave the theory  (which is now proven) that all planets revolve around the sun,  which is called the heliocentric model of theâ¦ solar system. The  belief at the time was that the Earth was the center of the solar  system/universe.