Which theory places the Sun at the center of the universe?

• A. Geocentric Theory
• B. Copernican Model
• C. Ptolemaic Model
• D. Heliocentric Theory

Answer: (D)

The main concept being tested is where the center of the cosmos is placed in a model of the solar system. A sun-centered view places the Sun at the center, and this idea is called heliocentric theory. In this framework, the planets—including Earth—orbit the Sun, which was a shift from earlier geocentric ideas that put Earth at the center. The Copernican Model is an early example of a sun-centered description, while the Ptolemaic and other geocentric models explain planetary motions with Earth at the center, often using epicycles. So the correct term for a Sun-centered model is heliocentric theory.