A reference to being focused on the sun.

A rule for designating each point in space by a set of numbers that are relative to how far something is to the sun as a center.

The principle that the earth and other planets revolve around the sun: following the work of Copernicus in the 16th century.

This replaced the earlier geocentric (earth-centered) system described by Ptolemy (c. A.D. 100-170).

Ptolemy was a Greek philosopher who presented a widely accepted model of the solar system known as the "Ptolemaic system". He also made important contributions to geography and cartography.

The "Ptolemaic system" was a theory developed by Ptolemy, about A.D. 150, maintaining a motionless earth is the center of the universe with sun, moon, and planets revolving, around it; while the fixed stars are attached to an outer sphere concentric with the earth. This model was generally accepted in the West until the establishment of the "Copernican theory" about 1500 years later.

Nicolaus Copernicus (1473-1543), is the Latinized version of the name Mikolaj Kopernik, the Polish astronomer who established the heliocentric model of the solar system; that is, the principle that the sun (not the earth) is the central point to which the motions of the planets are to be referred.

Copernicus was recognized as the first person in history to create a complete general arrangement of the solar system (Copernican system); combining mathematics, physics, and cosmology.