The German astronomer Johannes Kepler (1571-1630) was one of the chief founders of modern astronomy because of his discovery of three basic laws underlying the motion of planets.

Johannes Kepler was born on Dec. 27, 1571, in the Swabian town of Weil. His father, Heinrich Kepler, was a mercenary; although a Protestant, he enlisted in the troops of the Duke of Alba fighting the Reformed insurgents in the Low Countries. Kepler's grandmother brought him up; for years he was a sickly child. At 13 he was accepted at a theological seminary at Adelberg.

Kepler wanted to become a theologian, and following his graduation from the University of Tübingen, as bachelor of arts in 1591, he enrolled in its theological faculty. But he was also interested in French literature and astronomy. His poor health and proclivity to morbidness singled him out no less than did his precocious advocacy of the doctrine...