Johannes Kepler(1571-1630) established three laws of planetary motion after observing the elliptical orbit of Mars. He first published his theories on two laws in 'Astronomia nova' (1609) after spending nearly ten years as Tycho Brahe's assistant in Prague; and concluded with a third in 'Harmonice mundi' (1619).

Recognising something close to the theory of gravity, Kepler proposed that the sun controlled the planets by magnetic force, and published his "Rudolphine Tables" of planetary motion in 1627, which remained in use into the eighteenth century.