21^st Century Astronomy, Second Edition

Chapter 20: Our Expanding Universe

Study Plan

Just as stars make up the structure of our own galaxy, so too do galaxies make up the structure of the universe itself. Observations of the motions of galaxies led to one of the most remarkable discoveries in the history of our species: The universe is expanding! As we investigate this discovery we will learn

• About the discovery of Hubble's Law relating the redshift of a galaxy to its distance.
• That galaxies are not flying apart through space, but rather "ride along" as space itself expands in accordance with the general theory of relativity.
• How Hubble's Law is used to map the universe in space and look back in time.
• That spacetime itself was born approximately 13.7 billion years ago in an event called the Big Bang.
• That each of the major predictions of Big Bang theory, from the glow of the cosmic background radiation to the types of atoms that fill the universe, is confirmed by observation.
• How the history, shape, and fate of the universe are determined by the amount of mass it contains and by a poorly understood cosmological constant.
• What observations of the cosmic background tell us about the properties of the young universe.

Organize

1. Read Chapter 20 in your textbook or ebook.
2. Take the Diagnostic Quiz to assess your understanding of the basic concepts and identify gaps in your understanding of the assigned reading.

Learn

1. Access the Animations given for this chapter. These brief lessons enhance your understanding of core concepts.
   Hubble's Law
   Section: 20.2, 20.3, 20.4
2. Use the FlashCards to test your memory for new terms.
3. Review Foundations Box 20.1 on When Redshift Exceeds 1.
4. Work the "Thinking about the Concepts" and "Applying the Concepts" questions in the end of chapter review materials.
5. If your instructor has assigned SmartWork online homework, login from the right navigation pane for additional practice and review.

Connect

1. Periodic Connections boxes and the Seeing the Forest through the Trees section at the chapter's end draw your attention to recurring themes and help prepare you for concepts explored more fully in subsequent chapters.
2. Visit Astronomy in the News for breaking news of new discoveries and the opportunity to apply what you've learned in this chapter to real-world (and real Universe) events.

Instructors now have an easy way to collect students’ online quizzes with the Norton Gradebook without flooding their inboxes with e-mails.

Students can track their online quiz scores by setting up their own Student Gradebook.