The Solar System

x CONTENTS

Part 5: Life

Chapter 26 |Astrobiology: Life on Other
Worlds 581
26-1 THE NATURE OF LIFE 582
26-2 LIFE IN THE UNIVERSE 586
26-3 INTELLIGENT LIFE IN THE UNIVERSE 595

How Do We Know?

26-1The Nature of Scientifi c Explanation 583

26-2UFOs and Space Aliens 596

Concept Art Portfolio

DNA: The Code of Life 584–

AFTERWORD 602

APPENDIX A UNITS AND ASTRONOMICAL DATA 604

APPENDIX B OBSERVING THE SKY 612

GLOSSARY 625

ANSWERS TO EVEN-NUMBERED PROBLEMS 633

INDEX 635