Chemistry of Space DAVID E. NEWTON icsnfm.indd i 7/30/07 11:12:36 AM One Last Time . for John McArdle, Lee Nolet, Richard Olson, David Parr, David Rowand, Jeff Williams, and John D’Emilio Thanks for ◆the memories! Chemistry of Space Copyright © 2007 by David E. Newton All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For information contact: Facts On File, Inc. An imprint of Infobase Publishing 132 West 31st Street New York NY 10001 ISBN-10: 0-8160-5274-3 ISBN-13: 978-0-8160-5274-5 Library of Congress Cataloging-in-Publication Data Newton, David E. Chemistry of space / David E. Newton. p. cm. — (The new chemistry) Includes bibliographical references and index. ISBN: 0-8160-5274-3 (acid-free paper) 1. Cosmochemistry. 2. Interstellar matter. 3. Stars—Evolution. I. Title. QB450.N49 2007 523'02—dc22 2006037373 Facts On File books are available at special discounts when purchased in bulk quantities for businesses, associations, institutions, or sales promotions. Please call our Special Sales Department in New York at (212) 967-8800 or (800) 322-8755. You can fi nd Facts On File on the World Wide Web at http://www.factsonfi le.com Text design by James Scotto-Lavino Illustrations by DiacriTech, LLC Project editing by Dorothy Cummings Printed in the United States of America MP CGI 10 9 8 7 6 5 4 3 2 1 This book is printed on acid-free paper. icsnfm.indd ii 7/30/07 11:12:39 AM ◆ CONTENTS Preface vii Introduction ix 1 THE BIRTH OF THE UNIVERSE 1 In the Beginning 1 Georges Edouard Lemaître (1894–1966) 2 A Cooling Universe 5 Particle Decay 7 The Formation of Compound Particles 8 And Then There Were Atoms 11 Is the Theory True? 13 George Gamow (1904–1968) 16 Where to Next? 19 2 THE CHEMISTRY OF INTERSTELLAR SPACE 21 The Composition of the Interstellar Medium 22 Interstellar Clouds 29 Robert Julius Trumpler (1886–1956) 30 Chemistry of the Interstellar Medium 34 Tools for Studying the Chemical Characteristics of the ISM 39 Hendrik Christoffel van de Hulst (1918–2000) 40 3 FORMATION OF THE HEAVY ELEMENTS 47 Stellar Evolution 48 iii icsnfm.indd iii 7/30/07 11:12:39 AM Classifying Stars 49 Annie Jump Cannon (1863–1941) 50 A Star Is Born 55 Turning Hydrogen into Helium 61 Helium Burning . and Beyond 66 Bigger Stars = More Elements 69 Margaret Burbidge (1919– ) and Geoffrey Burbidge (1925– ) 74 4 THE INNER PLANETS 81 Studying the Chemical Composition of a Planet 82 Mercury 90 Venus 94 The Hubble Space Telescope 108 Mars 111 Asaph Hall (1829–1907) 122 5 THE OUTER PLANETS 126 Missions to the Outer Planets 127 Jupiter 132 S. Alan Stern (1957– ) 134 The Jovian Moons 143 Saturn 151 Uranus 156 Neptune 161 Pluto 164 James E. Webb (1906–1992) 165 Kuiper Belt Objects 167 Gerard Peter Kuiper (1905–1973) 168 6 COMETS, METEORS, ASTEROIDS, AND THE MOON 171 Comets 172 Edmund Halley (1656–1742) 176 Meteors, Meteoroids, and Meteorites 192 Asteroids 202 The Moon 216 icsnfm.indd iv 7/30/07 11:12:39 AM CONCLUSION 227 Glossary 229 Further Reading 235 Index 239 icsnfm.indd v 7/30/07 11:12:39 AM icsnfm.indd vi 7/30/07 11:12:40 AM ◆ PREFACE he subject matter covered in introductory chemistry classes at Tthe middle and high school levels tends to be fairly traditional and relatively consistent from school to school. Topics that are typically covered in such classes include atomic theory, chemical periodicity, ionic and covalent compounds, equation writing, stoi- chiometry, and solutions. While these topics are essential for stu- dents planning to continue their studies in chemistry or the other sciences and teachers are correct in emphasizing their importance, they usually provide only a limited introduction to the rich and ex- citing character of research currently being conducted in the fi eld of chemistry. Many students not planning to continue their studies in chemistry or the other sciences may benefi t from information about areas of chemistry with immediate impact on their daily lives or of general intellectual interest. Indeed, science majors themselves may also benefi t from the study of such subjects. The New Chemistry is a set of six books intended to provide an overview of some areas of research not typically included in the beginning middle or high school curriculum in chemistry. The six books in the set—Chemistry of Drugs, Chemistry of New Materials, Forensic Chemistry, Chemistry of the Environment, Food Chemistry, and Chemistry of Space—are designed to provide a broad, general introduction to some fi elds of chemistry that are less commonly mentioned in standard introductory chemistry courses. They cover topics ranging from the most fundamental fi elds of chemistry, such as the origins of matter and of the universe, to those with impor- tant applications to everyday life, such as the composition of foods vii icsnfm.indd vii 7/30/07 11:12:40 AM viii CHEMISTRY OF SPACE and drugs. The set title The New Chemistry has been selected to emphasize the extensive review of recent research and advances in each of the fi elds of chemistry covered in the set. The books in The New Chemistry set are written for middle school and high school readers. They assume some basic understanding of the principles of chemistry that are generally gained in an introductory middle or high school course in the subject. Every book contains a large amount of material that should be accessible to the interested reader with no more than an introductory understanding of chemistry and a smaller amount of material that may require a more advanced understanding of the subject. The six books that make up the set are independent of each other. That is, readers may approach all of the books in any sequence what- soever. To assist the reader in extending his or her understanding of each subject, each book in the set includes a glossary and a list of additional reading sources from both print and Internet sources. Short bibliographic sketches of important fi gures from each of the six fi elds are also included in the books. icsnfm.indd viii 7/30/07 11:12:40 AM ◆ INTRODUCTION pace and astronomy is the oldest of all sciences. Long before hu- Smans understood the composition of rocks and minerals, knew how chemical reactions take place, or even discovered how their own bodies were constructed and operated, they knew of the exis- tence of bodies beyond the Earth’s atmosphere: other planets, stars, and a variety of strange objects for which they had only simple ex- planations. The knowledge that early astronomers had of the skies was quite remarkable. They were able to predict the motion of stars, the arrival of seasons, the appearance of eclipses, and other astro- nomical phenomena with an accuracy that is quite astonishing to modern scientists. Although it qualifi es as the oldest of all sciences, space and as- tronomy has often been called the most diffi cult. Geologists can pick up and analyze the rocks they would like to study. Chemists can create the conditions under which almost any chemical reaction can be studied. Biologists are able to dissect living organisms and fi nd out how they are composed and how they function, but astronomers have only tiny bits of light with which to study the objects of their fi eld. They must devise ingenious methods for capturing that light and analyzing it in as many ways as possible. The information gained by astronomers using these limited resources is truly amazing. The challenge faced by astrochemists—scientists who study the chemical composition of astronomical bodies and the chemical changes that take place within them—is at least as daunting as it is to researchers in other fi elds of astronomy. They must fi nd ways to interpret the information a beam of light gives about the elements ix icsnfm.indd ix 7/30/07 11:12:40 AM x CHEMISTRY OF SPACE and compounds present in its source—a star or a dust cloud, for ex- ample—where those elements and compounds may have come from originally, and what kinds of chemical changes they are undergoing. Yet astrochemists have managed to deduce an impressive amount of information about our universe, the events through which it was created, the changes that have taken place during its evolution, and its present composition. Some of that information relates to the most basic questions in all of chemistry; for instance, where did funda- mental particles, such as protons and neutrons, come from, and how were the elements created. Although many important facts are still missing, astrochemists are able to respond to these questions and to explain much about how the world we live in has come to be as it is. Astrochemists can also tell us a great deal about the nature of solar bodies that fascinate and intrigue all of us. What is Venus like? Where did the Moon come from? What is the composition of giant planets like Jupiter and Saturn? Can Mars support life? Questions like these that people with little or no background in astronomy are likely to ask can now be answered, to at least some extent. The purpose of Chemistry of Space is to provide an overview of the latest information about the solar system, the planets, comets, and meteors, and other features of our universe that has become available as a result of research in astrochemistry.