Copernicus's theory (1543)

Nicolas Copernicus (1473-1543) was a Polish astronomer and canon of the church who became interested in the advantages of the heliocentric theory: the idea that the earth revolves around the sun, rather than the other way around. While the theory was not new, having been suggested at least as early as the third century BCE by the Greek astronomer Aristarchus, the "geocentric concept"—a stationary earth circled by all heavenly bodies traveling in perfect circles—had been held since the time of Aristotle. Copernicus argued for the heliocentric approach—largely on the grounds of simplicity—in his great book, On the Revolutions of the Celestial Spheres, published in 1543. Galileo and Kepler later ironed out some unsolved problems in his theory, thus paving the way for Newton's Principia (1687).

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