Beyond the Solar System: Exploring Galaxies, Black Holes, Alien Planets, and More; A History with 21 Activities
Time Line Prehistory Humans believe that a deity or deities created their flat world covered with a dome like sky They mark the passage of time with lunar phases and observe visible planets with the naked eye Ancient Chinese Babylonians Greeks and Times Egyptians record their observations of the night sky 140 BC Hipparchus creates an accurate map of the 1 000 or so brightest stars AD 100 Ptolemy publishes The Almagest 140 Ptolemy states that Earth is the center of the cosmos 964 Abd al Rahman al Sufi publishes his Book of Fixed Stars 1543 Nicolaus Copernicus states that the Sun is the center of the solar system 1572 After observing an exploding star Tycho Brahe writes that changes occur in the heavens
1608 Hans Lippershey invents the refracting telescope 1609 builds the first astronomical telescope Galileo and begins observations Galilei 1610 Galileo Galilei observes the phases of Venus confirming a sun centered cos mOS 1668 Isaac builds the first reflecting telescope Newton 1687 Isaac Newton publishes his theory of universal gravitation 1705 Edmond Halley correctly predicts the return of a comet which reappears 53 years later 1781 William Herschel discovers
doubling the size of the solar system 1790 William Herschel discovers planetary nebulas 1860 William Huggins begins the spectral analysis of stars 1905 publishes his theory of special relativ Albert ity Einstein 1912 Henrietta Leavitt discovers a method of measuring distances of galaxies using Cepheids 1913 Ejnar Hertzsprung and Henry Russell discover the relationship between stars color and brightness 1915 Albert Einstein publishes his theory of general relativity 1919 Sir Arthur Eddington confirms Ein stein's theory of general relativity by photographing a solar eclipse 1923 Edwin Hubble proves that there are other galaxies outside the Milky Way
