Beyond the Solar System: Exploring Galaxies, Black Holes, Alien Planets, and More; A History with 21 Activities
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
1926 Robert Goddard launches the first liq uid fueled rocket paving the way for space exploration 1927 Robert Atkinson and Fritz Houtermans determine that stars are fueled by nuclear fusion 1929 discovers that the universe is expand Edwin ing Hubble 1931 Georges Lemaitre suggests the uni verse began in a huge explosion the Big Bang 1932 Jansky discovers cosmic Karl radiowaves 1933 Fritz Zwicky discovers evidence of dark matter 1957 World's first satellite Sputnik 1 orbits Earth 1963 Maarten Schmidt discovers quasars 1965 Arno Penzias and Robert Wilson dis cover cosmic microwave background
from the Big Bang 1967 Jocelyn Bell discovers pulsars 1969 Donald Lynden Bell discovers that there are supermassive black holes in the center of every galaxy 1986 Mar and John Huchra discover the struc garet ture in the universe Geller 1990 Hubble Space Telescope launches 1991 Compton Gamma Ray Observatory launches 1995 Michel Mayor and Didier Queloz dis cover the first exoplanet 51 Pegasi B 1998 Teams of scientists determine that the universe's expansion is accelerating possibly due to dark energy 1999 Chandra X ray Observatory launches 2003 Spitzer Space Telescope launches 2009 Planet finding space telescope Kepler launches
