Scientific Discoveries By kmaslanks Jan 30, 1609 Johannes Kepler: first two laws of planetary motion Jan 30, 1610 Galileo Galilei: Sidereus Nuncius: telescopic observations Jan 30, 1665 Robert Hooke: Discovers the Cell Jan 30, 1669 Nicholas Steno: Proposes that fossils are organic remains embedded in layers of sediment, basis of stratigraphy Jan 30, 1687 Newton: Mathematical description of gravity Jan 30, 1751 Benjamin Franklin: Lightning is electrical Jan 30, 1781 William Herschel announces discovery of Uranus, expanding the known boundaries of the solar system for the first time in modern history Jan 30, 1789 Antoine Lavoisier: law of conservation of mass, basis for chemistry, and the beginning of modern chemistry Jan 30, 1859 Charles Darwin and Alfred Wallace: Theory of evolution by natural selection