THE HANDYY ASTRONOMY AS O OMY ANSWERANS ER BOOKOOK Charles Liu Your Smart Reference™ About the Author Charles Liu is a professor of astrophysics at the City University of New York’s College of Staten Island, and an associate with the Hayden Plane- tarium and Department of Astrophysics at the American Museum of Natural History in New York. His research focuses on colliding galaxies, quasars, starbursts, and the star formation his- tory of the universe. He earned degrees from Harvard University and the University of Ari- zona, and did postdoctoral research at Kitt Peak National Observatory and at Columbia Universi- ty. Along with numerous academic research publications, he also writes the astronomy col- umn “Out There” for Natural History Magazine. Together with co-authors Neil Tyson and Robert Irion, he received the 2001 American Institute of Physics Science Writing Award for their book One Universe: At Home in the Cosmos. He received the 2005 Award for Popular Writing on Solar Physics from the American Astronomical Society. He lives in New Jersey with his wife, daughter, and sons. 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THE HANDY ASTRONOMY ANSWER BOOK THE HANDYH DY ASTRONOMYARO ANSWERA BOOKO Charles Liu Detroit THE Copyright © 2008 by Visible Ink Press® This publication is a creative work fully protected by all applicable copyright laws, as well as by misappropriation, trade secret, unfair competition, and other HANDY applicable laws. No part of this book may be reproduced in any form without permission in writ- ASTRONOMY ing from the publisher, except by a reviewer who wishes to quote brief passages in connection with a review written for inclusion in a magazine, newspaper, or ANSWER web site. BOOK All rights to this publication will be vigorously defended. Visible Ink Press® 43311 Joy Rd., #414 Canton, MI 48187-2075 Visible Ink Press is a registered trademark of Visible Ink Press LLC. Most Visible Ink Press books are available at special quantity discounts when purchased in bulk by corporations, organizations, or groups. Customized print- ings, special imprints, messages, and excerpts can be produced to meet your needs. For more information, contact Special Markets Director, Visible Ink Press, www.visibleink.com, or 734-667-3211. Managing Editor: Kevin S. Hile Typesetting: Marco Di Vita Indexer: Lawrence W. Baker Proofreaders: Sarah Hermsen and Amy Marcaccio Keyzer ISBN 978-1-57859-193-0 Frontcover images: Young Stars Emerge from Orion’s Head (NASA/JPL-Caltech/ Laborato- rio de Astrofísica Espacial y Física Fundamental); Saturn’s Rings in Visible Light (NASA and E. Karkoschka, University of Arizona); Extreme Ultraviolet Imaging Telescope (EIT) image of a huge, handle-shaped prominence (ESA/NASA/SOHO); and Radio Frequency Telescope (iStock) Backcover image: Three Moons Cast Shadows on Jupiter (NASA, ESA, and E. Karkoschka: University of Arizona) Library of Congress Cataloging-in-Publication Data Liu, Charles, 1968 Apr. 5- The handy astronomy answer book / Charles Liu. p. cm. Includes index. ISBN-13: 978-1-57859-193-0 ISBN-10: 1-57859-193-7 1. Astronomy--Miscellanea. I. Title. QB52.L58 2008 520--dc22 2008023254 Printed in Malaysia by Imago. 10 9 8 7 6 5 4 3 2 1 Contents I NTRODUCTION ix ACKNOWLEDGMENTS xi I NDEX 319 ASTRONOMY STARS 89 FUNDAMENTALS 1 Star Basics … Mapping the Stars … Important Disciplines in Astronomy … Describing and Measuring Stars … How History of Astronomy … Medieval and Stars Work … Sunspots, Flares, and Solar Renaissance Astronomy … Eighteenth- and Wind … Star Evolution … The Sun … Nineteenth-Century Advances … Matter and Dwarf Stars and Giant Stars … Neutron Energy … Time, Waves, and Particles … Stars and Pulsars … Radiating Stars … Quantum Mechanics Binary Star Systems … Star Clusters THE UNIVERSE 33 Characteristics of the Universe … Origin of THE SOLAR SYSTEM 125 the Universe … Evidence of the Big Bang … Planetary Systems … Planet Basics … The Evolution of the Universe … Black Holes … Inner Solar System … Gas Giants … Wormholes and Cosmic Strings … Dark Moons … The Kuiper Belt and Beyond … Matter and Dark Energy … Multi-Dimension Asteroids … Comets Theories … The End of the Universe GALAXIES 59 EARTH AND Fundamentals … The Milky Way … THE MOON 161 The Milky Way’s Neighborhood … Galaxy Earth … Orbit and Rotation … The Movement … Age of Galaxies … Galactic Atmosphere … The Magnetic Field … Van Dust and Clouds … Nebulae, Quasars, and Allen Belts … Neutrinos … Cosmic Rays … Blazars … Black Holes in Galaxies … Meteors and Meteorites … The Moon … Active Galaxies … More Active Galaxies Tides … Clocks and Calendars … The and Quasars Seasons … Eclipses vii SPACE PROGRAMS 193 EXPLORING THE Rocket History … Satellites and Spacecraft SOLAR SYSTEM 263 … The Sputnik Era … Communications Exploration Basics … Exploring the Sun … Satellites … First Humans in Space … Exploring Mercury and Venus … Exploring Early Soviet Programs … Early American Mars … Failed Mars Missions … Mars Programs … The Apollo Missions … Early Missions in the Twenty-First Century … Space Stations … The Space Shuttle Exploring the Outer Planets … Exploring Asteroids and Comets ASTRONOMY TODAY 225 Measuring Units … Telescope Basics … LIFE IN Photography and Photometry … THE UNIVERSE 297 Spectroscopy … Interferometry … Radio Living in Space … Life on Earth and on the Telescopes … Microwave Telescopes … Moon … Life in Our Solar System … Solar Telescopes … Special Telescopes … Searching for Intelligent Life … Exoplanets Terrestrial Observatories … Airborne and … Life on Exoplanets Infrared Observatories … Space Telescopes … Infrared Space Telescopes … X-Ray Space Telescopes … Ultraviolet Space Telescopes … Gamma-Ray Space Telescopes viii Introduction Why do the stars shine? What happens when you fall into a black hole? What’s the Moon made of? Is Pluto a planet or not? Does extraterrestrial life exist? How old is Earth? Can humans live in outer space? What is a quasar? How did the universe begin? How will it end? When it comes to the cosmos, it seems like everyone has a thousand questions. Well, you’re in luck—this book has a thousand answers. Actually, it contains more than a thousand answers to more than a thousand questions about the universe and how it works. These pages contain far more, though, than a mere compilation of facts and figures. Together, these questions and answers tell the story of astronomy—of the cosmos and its contents, and of human- ity’s efforts throughout history to unlock its secrets and solve its mysteries. Since the dawn of civilization, people have tried to understand the objects in the heavens—what they are, how they move, and why. At first, it was a total mys- tery; our ancient ancestors created myths and stories, and ascribed supernatural qualities to the stars and planets. Slowly, they learned that the heavens and its con- tents were natural, not supernatural, and that everyone, not just a privileged few, could understand them. Slowly, the science of astronomy was born. What is science? It sure isn’t a bunch of facts in a big thick book that old folks in lab coats think you should memorize, regurgitate, and forget. Science is a process of asking questions and seeking answers by weighing the facts, making edu- cated guesses, and then testing those guesses with predictions, experiments, and observations. That’s what this book is all about: the unquenchable impulse to ask questions and seek answers. You’ll read about the questions that were asked, the people who asked them, how they tried to find the answers, and what they discov- ered in the process. We owe what we know about the universe to the tireless work of those questioners—those men and women who laid the foundation of astrono- my, who searched at the frontiers of knowledge. And that search goes on. In modern times, our species has seen to the edge of the observable universe with ground-based and space-borne telescopes. We have explored distant worlds with robotic spacecraft. We have even started to take our ix first baby steps into space ourselves. And yet, the more we learn and experience, the more we realize how much we still don’t know. This book contains a thousand answers, and that’s just a start. May those answers lead you to a thousand more questions; and like those scientific explorers who came before us, may you also experience the joy of discovery as you seek—and find—the answers! x Acknowledgments Thank you, Kevin Hile, for being a great editor, and thank you, Roger Jänecke, for being a great publisher. The two of you, more than anyone else, have shepherded this book to its happy completion. To you and those who work with you, I am grateful! Thank you to Phillis Engelbert and Diane Dupuis, and to everyone who helped them create The Handy Space Answer Book back in the late-20th century. Their efforts planted the seed that eventually sprouted this book.