Galileo Galilei (1564–1642) provided the mathematical formulas for the laws of the motion of planetary and physical bodies. Building on the 16th century Copernican hypothesis that the earth and planets revolved around the sun, the observations of Tycho Brahe (1546–1601), and the calculations of Johannes Kepler (1571–1630), Galileo's formulas put to rest the earth-centric notion of the universe put forward by the second-century astronomer Ptolemy—a notion that underlay European thinking about the universe for centuries. The philosophy of Francis Bacon (1561–1626) and the physico-mathematical work of René Descartes (1596–1650) and Blaise Pascal (1623–1662) enabled Isaac Newton (1642–1727) to state in 1665–66 that gravity accounts for the motion and structure of the universe.