Johannes Kepler

Kepler, Johannes (1571–1630), German mathematician and astronomer. Kepler advanced Copernicus's heliocentric model of the solar system in showing that the planets followed elliptical paths. His 3 laws describing the revolution of the planets around the sun, presented in Astronomia nova (1609) and Harmonice mundi (1619), guided Isaac Newton to the formulation of his theory of gravitation.

See also: Copernicus, Nicolaus; Newton, Sir Isaac.