Beginning in the latter half of the 15th cent., a humanist faith in classical scholarship led to the search for ancient texts that would increase current scientific knowledge. Among the works rediscovered were Galen's physiological and anatomical studies and Ptolemy's Geography. Botany, zoology, magic, alchemy, and astrology were developed during the Renaissance as a result of the study of ancient texts. Scientific thinkers such as Leonardo da Vinci, Nicolaus Copernicus, Galileo, Tycho Brahe, and Johannes Kepler attempted to refine earlier thought on astronomy. Among Leonardo's discoveries were the revelation that thrown or shot projectiles move in one curved trajectory rather than two; metallurgical techniques that allowed him to make great sculptures; and anatomical observations that increased the accuracy of his drawings.
In 1543 Copernicus wrote De revolutionibus, a work that placed the sun at the center of the universe and the planets in semicorrect orbital order around it; his work was an attempt to revise the earlier writings of Ptolemy. Galileo's most famous invention was an accurate telescope through which he observed the heavens; he recorded his findings in Siderius nuncius [starry messenger] (1610). Galileo's Dialogo … sopra i due massimi sistemi del mondo [dialogue concerning the two chief world systems] (1632), for which he was denounced by the current pope (because of Galileo's approval of Copernicus), resulted in his living under house arrest for the rest of his life. Tycho Brahe gave an accurate estimate of planetary positions and refuted the Aristotelian theory that placed the planets within crystal spheres. Kepler was the first astronomer to suggest that planetary orbits were elliptical.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.