Description
From Dana and Mike
We are excited that you are taking an astronomy course and using our book. You are going to see and learn about some amazing things, from the icy rings of Saturn to monster black holes. We are proud to be your guides as you explore.
We have developed this book to help you expand your knowledge of astronomy, from recognizing the moon and a few stars in the evening sky, to a deeper understanding of the extent, power, and diversity of the universe. You will meet worlds where it rains methane, stars so dense their atoms are crushed, colliding galaxies that are ripping each other apart, and a universe that is expanding faster and faster.
Two Goals
This book is designed to help you answer two important questions:
• What are we?
• How do we know?
By the question “What are we?” we mean: How do we fi t into the universe and its history? Th e atoms you are made of had their fi rst birthday in the big bang when the universe began, but those atoms were cooked and remade inside stars, and now they are inside you. Where will they be in a billion years? Astronomy is the only course on campus that can tell you that story, and it is a story that everyone should know. By the question “How do we know?” we mean: How does science work? What is the evidence, and how do we use it? For instance, how can anyone know there was a big bang? In today’s world, you need to think carefully about the things so-called experts say. You should demand evidence, not just explanations. Scientists have a special way of knowing based on evidence that makes scientific knowledge much more powerful than just opinion, policy, marketing, or public relations. It is the human race’s best understanding of nature. To comprehend the world around you, you need to understand how science works. Throughout this book, you will find boxes called How Do We Know? They will help you understand how scientists use the methods of science to know what the universe is like.
Expect to Be Astonished
One reason astronomy is exciting is that astronomers discover new things every day. Astronomers expect to be astonished. You can share in the excitement because we have worked hard to include new images, new discoveries, and new insights that will take you, in an introductory course, to the frontier of human knowledge. Huge telescopes on remote mountaintops and in space provide a daily dose of excitement that goes far beyond entertainment. These new discoveries in astronomy are exciting because they are about us. They tell us more and more about what we are. As you read this book, notice that it is not organized as lists of facts for you to memorize. Rather, this book is organized to show you how scientists use evidence and theory to create logical arguments that explain how nature works. Look at the list of special features that follows this note. Those features were carefully designed to help you understand astronomy as evidence and theory. Once you see science as logical arguments, you hold the key to the universe.
Don’t Be Humble
As teachers, our quest is simple. We want you to understand your place in the universe—your location not just in space but in the unfolding history of the physical universe. We want you not only to know where you are and what you are in the universe but also to understand how scientists know. By the end of this book, we want you to know that the universe is very big but that it is described and governed by a small set of rules and that we humans have found a way to figure out the rules—a method called science. To appreciate your role in this beautiful universe, you need to learn more than just the facts of astronomy. You have to understand what we are and how we know. Every page of this book reflects that ideal.