2 (b.a.) Geocentric
Most early Greek astronomers believed the universe to be perfect, with Earth at the center. The Greeks thought that Earth is inside a rotating dome they called the celestial sphere. Since geo is the Greek word for “Earth,” an Earth-centered model is known as a geocentric (jee oh sen trik) system. In a geocentric system, Earth is at the center of the revolving planets and stars.
About a.d. 140, the Greek astronomer Ptolemy (tahl uh mee) further developed the geocentric model. Like the earlier Greeks, Ptolemy thought that Earth is at the center of a system of planets and stars.
Even though Ptolemy’s geocentric model was incorrect, it explained the motions observed in the sky fairly accurately. As a result, the geocentric model of the universe was widely accepted for nearly 1,500 years after Ptolemy.
What is a geocentric system?
About a.d. 140, the Greek astronomer Ptolemy (tahl uh mee) further developed the geocentric model. Like the earlier Greeks, Ptolemy thought that Earth is at the center of a system of planets and stars.
Even though Ptolemy’s geocentric model was incorrect, it explained the motions observed in the sky fairly accurately. As a result, the geocentric model of the universe was widely accepted for nearly 1,500 years after Ptolemy.
What is a geocentric system?