Resolution of the Theoretical Objections to the Heliocentric Theory

When Copernicus’s Six Books on the Revolutions of the Heavenly Spheres was published in 1543, he faced a number of theoretical objections to his theory. The hypotheses of rotation of the Earth and the Earth’s revolution around the Sun are central to the heliocentric theory but they are counter-intuitive. If the Earth is rotating eastward, then any object in the sky, such as flying birds and clouds, would be expected to drift in the opposite direction according to our common sense. In the sixteenth century, the understanding of the motion of objects was based on Aristotle’s distinction between “natural” and “violent” motions. If the rotation of the Earth is a natural motion (as it was interpreted by Copernicus) then a falling object would be left behind by the turning Earth. The fact that this is not observed was used as a strong argument against the rotation of the Earth.