10 Astronomers By nbortne1 137 Ptolemy creates a star catalog. Period: 1505 to 1514 Nicolaus Copernicus discovers the "Heliocentric Theory." 1543 Nicolaus Copernicus discovers the Earth's rotation around the Sun. Jan 7, 1610 Galileo Galilei discoveres Europa. Jan 7, 1610 Galileo Galilei discovers Ganymede. Jul 30, 1610 Galileo Discovers the rings of Saturn. 1611 Johannes Kepler upgrades the telescope. 1616 Johannes Kepler discovers the "Three Laws of Planetary Motion." 1666 Isaac Newton discovers gravity. 1666 Isaac Newton invents the first reflection telescope. Jun 14, 1770 Charles Messier discovers Lexell's Comet. Feb 13, 1781 William Herschel discovers Uranus. Jan 11, 1782 William Herschel discovers Titania. Apr 12, 1784 William Herschel discovers the dwarf elliptical galaxy known as NGC 4489. 1788 Charles Messier discovers C/1788 W1. Dec 21, 1788 Caroline Herschel discovers comet 35p/Herschel-Rigollet. Apr 17, 1790 Caroline Herschel discovers Comet C/1790 H1. 1901 Annie Jump Cannon develops a system that allows for the classification of stars. 1908 Albert Einstein creates the "Theory of Relativity." 1916 Albert Einstein predicts gravitational lensing.
