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
ASTRONOMY UNDERSTANDING CELESTIAL BODIES the advent of spectroscopes radio telescopes and observatories in Earth orbit and many other technological advances It takes a quick tour of the universe starting with our Earth's solar system then moving out into Earth's galaxy the Milky Way where other worlds orbit other stars and finally into intergalactic space and the billions of galaxies stretching to the unimag inably distant edge The book explains some of the strangest denizens of the celestial zoo from black holes so massive that nothing can escape their grav itational pull not even light to quasars that can shine more brightly than entire galaxies full of stars to the mysterious dark matter that affects the structure of the universe and yet remains an almost complete unknown The book concludes with the quest to answer some of the most fundamental questions science has ever faced how the universe was born how it has evolved and what its ultimate fate will be and how that quest has led to one of science's most famous theories even lending its name to a popular television show the big bang theory Scientists know far more about the uni verse and Earth's place within it than the 10
INTRODUCTION ancient people gazing up at the star spangled sky could have hoped to understand Ancient peoples made up stories based on the con stellations they saw in the night sky Today there exist actual photographs of space taken from a satellite Modern astronomy is said to have begun in the early sixteenth century Since then scientists have discovered so much about the universe Yet there is still so much more to learn Astronomy's most excit ing discoveries may well remain to be made 11
