Introduction to Planetary Science Introduction to Planetary Science The Geological Perspective GUNTER FAURE The Ohio State University, Columbus, Ohio, USA TERESA M. MENSING The Ohio State University, Marion, Ohio, USA A C.I.P. Catalogue record for this book is available from the Library of Congress. ISBN-13 978-1-4020-5233-0 (HB) ISBN-13 978-1-4020-5544-7 (e-book) Published by Springer, P.O. Box 17, 3300 AA Dordrecht, The Netherlands. www.springer.com Cover art: The planets of the solar system. Courtesy of NASA. A Manual of Solutions for the end-of-chapter problems can be found at the book’s homepage at www.springer.com Printed on acid-free paper All Rights Reserved © 2007 Springer No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. In memory of Dr. Erich Langenberg, David H. Carr, and Dr. Robert J. Uffen who showed me the way. Gunter Faure For Professor Tom Wells and Dr. Phil Boger who taught me to reach for the stars. Teresa M. Mensing Table of Contents Preface xvii 1. The Urge to Explore 1 1.1. The Exploration of Planet Earth 2 1.2. Visionaries and Rocket Scientists 4 1.3. Principles of Rocketry and Space Navigation 7 1.4. Summary 9 1.5. Science Briefs 10 1.6. Problems 11 1.7. Further Reading 11 2. From Speculation to Understanding 13 2.1. The Geocentric Cosmology of Ancient Greece 13 2.2. The Scientific Method 14 2.3. Units of Measurement 16 2.3.1. Distance 16 2.3.2. Time 17 2.3.3. Velocity and Speed 17 2.3.4. Mass 18 2.3.5. Temperature 18 2.3.6. Pressure 19 2.4. Summary 19 2.5. Science Briefs 20 2.6. Problems 21 2.7. Further Reading 21 3. The Planets of the Solar System 23 3.1. The Sun and the Planets of the Solar System 23 3.2. The Titius-Bode Rule 25 3.3. Average Orbital Velocities 27 3.4. Surface Temperatures 28 3.5. Bulk Densities 28 3.6. Summary 32 3.7. Science Briefs 32 3.8. Problems 34 3.9. Further Reading 34 4. Life and Death of Stars 35 4.1. The Big Bang 35 4.2. Stellar Evolution 39 4.3. Nucleosynthesis 41 vii viii table of contents 4.4. The Milky Way Galaxy 44 4.5. Summary 45 4.6. Science Briefs 46 4.7. Problems 47 4.8. Further Reading 48 5. Origin of the Solar System 49 5.1. The Solar Nebula 49 5.2. Origin of the Sun and Planets 50 5.3. The Sun 53 5.3.1. Internal Structure 53 5.3.2. Energy Production 56 5.3.3. Magnetism and Sunspots 57 5.3.4. Effect on Space 59 5.3.5. Life and Death of the Sun 59 5.4. Summary 61 5.5. Science Briefs 62 5.6. Problems 62 5.7. Further Reading 63 6. Earth: Model of Planetary Evolution 65 6.1. Growth from Planetesimals 65 6.2. Internal Differentiation 67 6.3. Atmosphere 69 6.4. Interior of the Earth 72 6.4.1. Temperature 72 6.4.2. Melting of Peridotite 72 6.4.3. Mantle Plumes 73 6.4.4. Plate Tectonics 74 6.4.5. Magnetic Field 76 6.5. Interactions with the Solar Wind 79 6.6. Summary 81 6.7. Science Briefs 82 6.8. Problems 85 6.9. Further Reading 85 7. The Clockwork of the Solar System 87 7.1. The Pioneers of Astronomy 87 7.2. Elliptical Orbits of Planets 89 7.2.1. Eccentricity 89 7.2.2. Average Distance 90 7.2.3. Revolution and Rotation 90 7.2.4. Plane of the Ecliptic 91 7.2.5. Axial Obliquity 91 7.2.6. Conjunctions and Oppositions 92 7.2.7. Sidereal and Synodic Periods of Revolution 95 7.2.8. Solar and Lunar Eclipses 96 7.2.9. Orbital Velocities 96 7.2.10. Launching Satellites into Orbit 98 7.2.11. Lagrange Points 99 7.3. Celestial Mechanics of the Earth 100 7.3.1. Rising and Setting of the Sun 100 7.3.2. Change in the Period of Rotation 101 7.3.3. Seasons of the Northern Hemisphere 101 table of contents ix 7.3.4. The Earth at Summer Solstice 101 7.3.5. Autumnal and Vernal Equinoxes 102 7.3.6. Milankovitch Cycles 103 7.4. The Gregorian Calendar 104 7.5. Summary 105 7.6. Science Briefs 105 7.7. Problems 107 7.8. Further Reading 107 8. Meteorites and Impact Craters 109 8.1. Classification and Mineralogy of Meteorites 110 8.2. Carbonaceous Chondrites 112 8.3. Tektites 114 8.4. Meteorite Parent Bodies 115 8.5. Celestial Mechanics 116 8.6. Falls and Finds 118 8.7. Age Determinations 120 8.8. Meteorite Impacts 122 8.8.1. Formation of Craters 122 8.8.2. Classification of Craters 123 8.8.3. Modification of Craters 124 8.8.4. Frequency of Impacts 125 8.8.5. Environmental Consequences (Tunguska, 1908) 126 8.9. Meteor Crater: Memorial to E.M. Shoemaker 127 8.10. Summary 131 8.11. Science Briefs 131 8.12. Problems 135 8.13. Further Reading 135 9. The Earth-Moon System 139 9.1. Landforms of the Lunar Surface 141 9.1.1. Highlands 141 9.1.2. Maria 142 9.1.3. Impact Craters 143 9.1.4. Regolith 143 9.1.5. Water 143 9.2. Isotopic Dating 145 9.3. Geology of the Near Side 145 9.4. Lunar Meteorites 149 9.5. Internal Structure 150 9.6. Origin of the Moon 152 9.7. Celestial Mechanics 154 9.7.1. Spin-Orbit Coupling 154 9.7.2. Lunar Orbit 155 9.8. Tides 156 9.8.1. Ocean Tides 156 9.8.2. Body Tides 157 9.9. Research Stations on the Moon 158 9.9.1. Weighing the Risks and Benefits 158 9.9.2. Utilization of Lunar Resources 159 9.10. Space Law 160 9.10.1. United Nations: Laws for States 160 x table of contents 9.10.2. NASA: Code of Conduct for Astronauts 161 9.11. Summary 162 9.12. Science Briefs 163 9.13. Problems 166 9.14. Further Reading 166 10. Mercury: Too Hot for Comfort 167 10.1. Surface Features 167 10.1.1. Impact Craters and Cliffs 167 10.1.2. Regolith 169 10.1.3. Atmosphere 169 10.1.4. Water 170 10.1.5. Surface Temperatures 170 10.2. Internal Structure 171 10.2.1. Iron Core 171 10.2.2. Magnetic Field 172 10.2.3. Geological Activity 173 10.3. Origin of Mercury 174 10.4. Celestial Mechanics 175 10.4.1. Spin-Orbit Coupling 176 10.4.2. The Solar Transit 177 10.4.3. Rotation of the Long Axis of the Orbit 177 10.5. Summary 178 10.6. Science Briefs 178 10.7. Problems 179 10.8. Further Reading 181 11. Venus; Planetary Evolution Gone Bad 183 11.1. Surface Features 184 11.2. Geological Processes 187 11.2.1. Volcanic Activity 187 11.2.2. Tectonic Activity 192 11.2.3. Impact Craters 194 11.3. Atmosphere and Climate 195 11.3.1. Chemical Composition and Structure 195 11.3.2. Circulation 197 11.3.3. Greenhouse Warming 197 11.3.4. Evolution of the Surface Environment 198 11.3.5. Carbon Cycles of Venus and the Earth 199 11.4. Internal Structure 201 11.4.1. The Core and Magnetism 201 11.4.2. Episodic Resurfacing 202 11.5. Celestial Mechanics 203 11.5.1. Retrograde Rotation 203 11.5.2. Phases, Conjunctions, and Transits 204 11.6. Summary 205 11.7. Science Briefs 206 11.8. Problems 209 11.9. Further Reading 209 12. Mars: The Little Planet that Could 211 12.1. Origin and Properties 213 12.1.1. Origin by Accretion of Planetesimals 213 table of contents xi 12.1.2. Physical and Chemical Properties 214 12.1.3. Evolution of the Atmosphere 215 12.1.4. Orbit of Mars 215 12.2. Surface Features: Northern Hemisphere 216 12.2.1. Tharsis Plateau 216 12.2.2. Olympus Mons 218 12.2.3. Young Lava Flows 219 12.2.4. Valles Marineris 220 12.2.5. Utopia Planitia 220 12.2.6. Soil of Utopia and Chryse 222 12.3. Surface Features: Southern Hemisphere 223 12.3.1. Hellas Impact Basin 224 12.3.2. Argyre Impact Basin 225 12.3.3. Isidis Impact Basin 225 12.3.4. Timescale for Mars 225 12.4. Volcanoes of the Southern Hemisphere 227 12.4.1. Syrtis Major Volcano 227 12.4.2. Hespera Planum 227 12.4.3. Hadriaca Patera 228 12.5. Stream Valleys 228 12.5.1. Nanedi Vallis 228 12.5.2. Nirgal Vallis 230 12.5.3. Vedra Valles 231 12.6. Impact Craters 231 12.7. Martian Meteorites 234 12.8. Water on Mars 235 12.8.1. Hydrologic Cycle 236 12.8.2. Phase Diagrams of Water and Carbon Dioxide 238 12.8.3. Polar Ice Caps 239 12.8.4. Mountain Glaciers and Continental Ice Sheets 241 12.9. Life on Mars 241 12.9.1.