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.
Copernicus proposed a heliocentric model of the solar system â a model where everything orbited around the Sun. Today, with advancements in science and technology, the geocentric model seems preposterous.Simple tools, such as the telescope â which helped convince Galileo that the Earth was not the center of the universe â can prove that ancient theory incorrect.opernicus proposed a heliocentric model of the solar system â a model where everything orbited around the Sun. Today, with advancements in science and technology, the geocentric model seems preposterous.