Astronomy Practice Exam

Who proposed the geocentric system of astronomy that remained undisputed for a long period?

1. Nicholas Copernicus

2. Tycho Brahe

3. Ptolemy

4. Johannes Kepler

The correct answer is: Ptolemy

The geocentric system, which posited that the Earth is at the center of the universe and that all celestial bodies revolve around it, was most prominently articulated by Ptolemy. His model, detailed in the work "Almagest," proposed a sophisticated system of deferents and epicycles to explain the observed motions of the planets. This model effectively accounted for the apparent movements of celestial bodies from the perspective of an observer on Earth and remained the dominant astronomical framework for over a millennium. Ptolemy's geocentric theory provided a comprehensive explanation for many astronomical phenomena and was widely accepted by scholars, intertwined with the prevailing philosophical and religious views of the time. It wasn't until the heliocentric model proposed by Copernicus, and subsequent improvements by later astronomers, that the geocentric view began to lose its standing. Understanding Ptolemy's contributions is essential as it highlights the historical context of astronomy, showcasing how perceptions of the universe evolved over time and leading to more accurate models of celestial mechanics.