Scientific Revolution - Theoretical Developments

Theoretical Developments

In 1543 Copernicus' work on the heliocentric model of the solar system was published, in which he tried to demonstrate that the sun was the center of the universe. Few were bothered by this suggestion, and the pope and several archbishops were interested enough by it to want more detail. His model was later used to create the calendar of Pope Gregory XIII. For almost two millennia, the geocentric model had been accepted by all but a few astronomers. The idea that the earth moved around the sun, as advocated by Copernicus, was to most of his contemporaries doubtful. It contradicted not only empirical observation, due to the absence of an observable stellar parallax, but also Aristotelian philosophy.

The discoveries of Johannes Kepler and Galileo gave the theory credibility. Kepler was an astronomer who, using the accurate observations of Tycho Brahe, proposed that the planets move around the sun not in circular orbits, but in elliptical ones. Together with his other laws of planetary motion, this allowed him to create a model of the solar system that was an improvement over Copernicus' original system. Galileo's main contributions to the acceptance of the heliocentric system were his mechanics, the observations he made with his telescope, as well as his detailed presentation of the case for the system. Using an early theory of inertia, Galileo could explain why rocks dropped from a tower fall straight down even if the earth rotates. His observations of the moons of Jupiter, the phases of Venus, the spots on the sun, and mountains on the moon all helped to discredit the Aristotelian philosophy and the Ptolemaic theory of the solar system. Through their combined discoveries, the heliocentric system gained support, and at the end of the 17th century it was generally accepted by astronomers.

Kepler's laws of planetary motion and Galileo's mechanics culminated in the work of Isaac Newton. His laws of motion were to be the solid foundation of mechanics; his law of universal gravitation combined terrestrial and celestial mechanics into one great system that seemed to be able to describe the whole world in mathematical formulae.

Not only astronomy and mechanics were greatly changed. Optics, for instance, was revolutionized by people like Robert Hooke, Christiaan Huygens, René Descartes and, once again, Isaac Newton, who developed mathematical theories of light as either waves (Huygens) or particles (Newton). Similar developments could be seen in chemistry, biology and other sciences, although their full development into modern science was delayed for a century or more.