Who proposed heliocentric theory?
A) Copernicus
B) Ptolemy
C) Newton
D) Tycho Brahe

Hint:Nicolaus Copernicus started the scientific revolution which was known to have started after the proposal of the heliocentric theory.

Complete step by step solution:
The heliocentric theory was proposed by Nicolaus Copernicus sometime between 1508 and 1514. He was a polish mathematician and astronomer. He proposed that the sun was at the center of the solar system and the earth and other planets revolved around it in circular orbits. Earlier, the idea of a geocentric universe was prevalent. It was believed that the earth was at the center of the universe and the sun and other planets revolved around it.

He was disturbed by the failure of Ptolemy’s geocentric model of the universe and believed that all problems could be solved by considering the heliocentric model of the universe. He was widely opposed and invited a lot of controversy because of this theory but it was the start of the scientific revolution.

Tycho Brahe was born a few years after Copernicus’s death. He was a Danish nobleman, astronomer and writer who was known for his highly accurate and comprehensive astronomical observations. He is best known for developing astronomical instruments and measuring and fixing the position of stars. Newton was born a century after Copernicus’s death. He was a mathematician, physicist, theologian and author and is most well-known for his laws of motion, the discovery of gravitation and the invention of calculus.

Note:Ptolemy was an ancient Greek mathematician and astronomer who held the view that the earth was at the center of the universe. Nicolaus Copernicus found that his theory was incorrect and proposed the heliocentric theory which later influenced Johannes Kepler.