71 Black Holes The Strangest of All Planets orbiting Other Stars Between the Stars 72 74 78 81 CHAPTER 4 THE GALAXIES Our Home Galaxy The Milky Way Energetic Galaxies Radio Galaxies and Quasars The Quasar Galaxy Connection Dark Matter The Expanding Universe 84 85 85 91 91 97 98 CHAPTER 5 THE UNIVERSE The Nature of the Universe Looking Deep The Hubble Space Telescope How the Big Bang Theory Was Developed Hubble Proves the Island Universe Theory Hubble's Law First Hints of the Big Bang The Steady State Challenge Cosmic Microwave Background Proves the Theory 99 1OO 103 106 110 117 GLOSSARY FOR MORE INFORMATION FOR FURTHER READING 120 124 INDEX 125
INTRODUCTION The Eagle Nebula as seen by the Infrared Space Observatory ESA ISO CAM The ISOGAL Team
INTRODUCTION stronomy began with ancient peo ples probably even before they were fully human looking up at the night sky and wondering at the points of light glittering across it As human civilizations advanced they peopled the heavens with gods and mythological creatures imagine ing them looking down on the Earth below and taking a keen interest in human affairs Those ancient stargazers looked to the skies for some hint of what the gods had planned for Earth and its people for signs of divine pleasure or wrath One could say then that the study of the heavens has always been focused on the big gest questions of human existence How did humans come to be here What will happen to humans in the future Does life exist else where in the universe Those are still questions that astronomy attempts to answer though scientists today are no longer trying to figure out the will of the gods by watching the movement of the stars and planets Instead they are trying to understand the birth and evolution of the universe This book examines the history of astron omy from before the invention of the telescope through the heady advances made possible by
