Astronomy Astronomy SENIOR CONTRIBUTING AUTHORS ANDREW FRAKNOI, FOOTHILL COLLEGE DAVID MORRISON, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SIDNEY C WOLFF, NATIONAL OPTICAL ASTRONOMY OBSERVATORY (E.
Astronomy SENIOR CONTRIBUTING AUTHORS ANDREW FRAKNOI, FOOTHILL COLLEGE DAVID MORRISON, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SIDNEY C WOLFF, NATIONAL OPTICAL ASTRONOMY OBSERVATORY (EMERITUS) OpenStax Rice University 6100 Main Street MS-375 Houston, Texas 77005 To learn more about OpenStax, visit https://openstax.org Individual print copies and bulk orders can be purchased through our website ©2017 Rice University Textbook content produced by OpenStax is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0) Under this license, any user of this textbook or the textbook contents herein must provide proper attribution as follows: - - - - If you redistribute this textbook in a digital format (including but not limited to PDF and HTML), then you must retain on every page the following attribution: “Download for free at https://openstax.org/details/books/astronomy.” If you redistribute this textbook in a print format, then you must include on every 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and Co-chair William H Gates Sr., under the direction of Bill and Melinda Gates and Warren Buffett The Maxfield Foundation supports projects with potential for high impact in science, education, sustainability, and other areas of social importance Our mission at The Michelson 20MM Foundation is to grow access and success by eliminating unnecessary hurdles to affordability We support the creation, sharing, and proliferation of more effective, more affordable educational content by leveraging disruptive technologies, open educational resources, and new models for collaboration between for-profit, nonprofit, and public entities The Bill and Stephanie Sick Fund supports innovative projects in the areas of Education, Art, Science and Engineering I WOULDN’T THIS PENS I LOOK BETTER TUDENT E ON A BRAND MEET SC E NEW IPAD QUIREMENT I MINI? URSES THESE AR EER-REVIEWED TEXTS WR ROFESSIONAL CONTENT EVELOPERS ADOPT A BO ODAY FOR A TURNKEY LASSROOM SOLUTION OR TO SUIT YOUR TEACHING PPROACH FREE ONLINE Knowing where our textbooks are used can help us provide better services to students and receive more grant support for future projects If you’re using an OpenStax textbook, either as required for your course or just as an extra resource, send your course syllabus to contests@openstax.org and you’ll be entered to win an iPad Mini If you don’t win, don’t worry – we’ll be holding a new contest each semester TABLE OF CONTENTS Preface 1 Science and the Universe: A Brief Tour 11 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 Observing the Sky: The Birth of Astronomy 31 2.1 2.2 2.3 2.4 54 The Laws of Planetary Motion 70 Newton’s Great Synthesis 76 Newton’s Universal Law of Gravitation 81 Orbits in the Solar System 85 Motions of Satellites and Spacecraft 88 Gravity with More Than Two Bodies 91 Earth, Moon, and Sky 103 4.1 4.2 4.3 4.4 4.5 4.6 4.7 The Sky Above 32 Ancient Astronomy 42 Astrology and Astronomy 49 The Birth of Modern Astronomy Orbits and Gravity 69 3.1 3.2 3.3 3.4 3.5 3.6 The Nature of Astronomy 13 The Nature of Science 13 The Laws of Nature 15 Numbers in Astronomy 15 Consequences of Light Travel Time 17 A Tour of the Universe 18 The Universe on the Large Scale 23 The Universe of the Very Small 27 A Conclusion and a Beginning 28 Earth and Sky 104 The Seasons 107 Keeping Time 114 The Calendar 117 Phases and Motions of the Moon 120 Ocean Tides and the Moon 125 Eclipses of the Sun and Moon 129 Radiation and Spectra 145 5.1 The Behavior of Light 146 5.2 The Electromagnetic Spectrum 153 5.3 5.4 5.5 5.6 Astronomical Instruments 189 6.1 6.2 6.3 6.4 6.5 6.6 The Global Perspective 266 Earth’s Crust 270 Earth’s Atmosphere 278 Life, Chemical Evolution, and Climate Change 283 Cosmic Influences on the Evolution of Earth 288 Cratered Worlds 303 9.1 9.2 9.3 9.4 9.5 10 Overview of Our Planetary System 234 Composition and Structure of Planets 246 Dating Planetary Surfaces 251 Origin of the Solar System 254 Earth as a Planet 265 8.1 8.2 8.3 8.4 8.5 Telescopes 190 Telescopes Today 196 Visible-Light Detectors and Instruments 206 Radio Telescopes 210 Observations outside Earth’s Atmosphere 217 The Future of Large Telescopes 222 Other Worlds: An Introduction to the Solar System 233 7.1 7.2 7.3 7.4 Spectroscopy in Astronomy 161 The Structure of the Atom 166 Formation of Spectral Lines 172 The Doppler Effect 176 General Properties of the Moon The Lunar Surface 310 Impact Craters 315 The Origin of the Moon 320 Mercury 321 303 Earthlike Planets: Venus and Mars 335 10.1 10.2 10.3 10.4 10.5 10.6 The Nearest Planets: An Overview 335 The Geology of Venus 342 The Massive Atmosphere of Venus 347 The Geology of Mars 350 Water and Life on Mars 359 Divergent Planetary Evolution 371 This OpenStax book is available for free at https://cnx.org/content/col11992/1.13 11 The Giant Planets 379 11.1 Exploring the Outer Planets 379 11.2 The Giant Planets 385 11.3 Atmospheres of the Giant Planets 12 Rings, Moons, and Pluto 407 12.1 12.2 12.3 12.4 12.5 13 473 Meteors 490 Meteorites: Stones from Heaven 495 Formation of the Solar System 500 Comparison with Other Planetary Systems Planetary Evolution 511 506 The Structure and Composition of the Sun 524 The Solar Cycle 535 Solar Activity above the Photosphere 540 Space Weather 544 The Sun: A Nuclear Powerhouse 559 16.1 16.2 16.3 16.4 17 Asteroids 450 Asteroids and Planetary Defense 460 The “Long-Haired” Comets 463 The Origin and Fate of Comets and Related Objects The Sun: A Garden-Variety Star 523 15.1 15.2 15.3 15.4 16 408 Cosmic Samples and the Origin of the Solar System 489 14.1 14.2 14.3 14.4 14.5 15 Ring and Moon Systems Introduced The Galilean Moons of Jupiter 409 Titan and Triton 418 Pluto and Charon 423 Planetary Rings 430 Comets and Asteroids: Debris of the Solar System 449 13.1 13.2 13.3 13.4 14 391 Sources of Sunshine: Thermal and Gravitational Energy Mass, Energy, and the Theory of Relativity 562 The Solar Interior: Theory 572 The Solar Interior: Observations 578 Analyzing Starlight 591 559 17.1 17.2 17.3 17.4 18 Fundamental Units of Distance 655 Surveying the Stars 659 Variable Stars: One Key to Cosmic Distances 668 The H–R Diagram and Cosmic Distances 675 The Interstellar Medium 688 Interstellar Gas 692 Cosmic Dust 700 Cosmic Rays 707 The Life Cycle of Cosmic Material 710 Interstellar Matter around the Sun 712 The Birth of Stars and the Discovery of Planets outside the Solar System 21.1 21.2 21.3 21.4 21.5 21.6 22 625 Between the Stars: Gas and Dust in Space 687 20.1 20.2 20.3 20.4 20.5 20.6 21 A Stellar Census 621 Measuring Stellar Masses Diameters of Stars 632 The H–R Diagram 637 Celestial Distances 655 19.1 19.2 19.3 19.4 20 605 The Stars: A Celestial Census 621 18.1 18.2 18.3 18.4 19 The Brightness of Stars 591 Colors of Stars 595 The Spectra of Stars (and Brown Dwarfs) 598 Using Spectra to Measure Stellar Radius, Composition, and Motion Star Formation 724 The H–R Diagram and the Study of Stellar Evolution 733 Evidence That Planets Form around Other Stars 736 Planets beyond the Solar System: Search and Discovery 740 Exoplanets Everywhere: What We Are Learning 748 New Perspectives on Planet Formation 754 Stars from Adolescence to Old Age 765 22.1 22.2 22.3 22.4 22.5 Evolution from the Main Sequence to Red Giants Star Clusters 772 Checking Out the Theory 776 Further Evolution of Stars 783 The Evolution of More Massive Stars 792 This OpenStax book is available for free at https://cnx.org/content/col11992/1.13 766 723