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Roger A. Freedman • William J. Kaufmann III. Universe Eighth Edition. CHAPTER 1 Astronomy and the Universe. Homework 1 Online quiz for Chapter 1 (see syllabus for URL) DUE Friday 9/3 by 5 PM. 1-1 What distinguishes the methods of science from other human activities
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Roger A. Freedman • William J. Kaufmann III Universe Eighth Edition CHAPTER 1 Astronomy and the Universe
Homework 1 Online quiz for Chapter 1 (see syllabus for URL) DUE Friday 9/3 by 5 PM
1-1 What distinguishes the methods of science from other human activities 1-2 How exploring other planets provides insight into the origins of the solar system and the nature of our Earth 1-3 Stars have a life cycle—they form, evolve over millions or billions of years, and die 1-4 Stars are grouped into galaxies, which are found throughout the universe 1-5 How astronomers measure the positions and sizes of celestial objects 1-6 How to express very large or very small numbers in convenient notation 1-7 Why astronomers use different units to measure distances in space 1-8 What astronomy can tell us about our place in the universe By reading this chapter, you will learn
Which of the following statements is true? • A solar system may contain billions of stars. • Stars are spread out more or less uniformly throughout the Universe. • The Milky Way contains a variety of solar systems, stars, and galaxies. • A galaxy contains billions of stars. • A solar system contains billions of galaxies. Q1.13
Which of the following statements is true? • A solar system may contain billions of stars. • Stars are spread out more or less uniformly throughout the Universe. • The Milky Way contains a variety of solar systems, stars, and galaxies. • A galaxy contains billions of stars. • A solar system contains billions of galaxies. Q1.13
The separation between the two pointer stars of the Big Dipper is 5 degrees. What is this separation in arcminutes? • 50 • 60 • 300 • 500 • 18,000 Q1.4
The separation between the two pointer stars of the Big Dipper is 5 degrees. What is this separation in arcminutes? • 50 • 60 • 300 • 500 • 18,000 A1.4
What lengths are most conveniently measured in units of nanometers (10−9 m)? • Distances between the planets • Distances between cities on Earth • Dimensions of the human body • Wavelengths of visible light • Diameter of an atom Q1.6
What lengths are most conveniently measured in units of nanometers (10−9 m)? • Distances between the planets • Distances between cities on Earth • Dimensions of the human body • Wavelengths of visible light • Diameter of an atom A1.6
What lengths are most conveniently measured in astronomical units (AU)? • Distances on the Earth • Distances within the solar system • Distances between stars in our Galaxy • Distances between galaxies • Only the largest distances in the universe Q1.5
What lengths are most conveniently measured in astronomical units (AU)? • Distances on the Earth • Distances within the solar system • Distances between stars in our Galaxy • Distances between galaxies • Only the largest distances in the universe A1.5
What is the approximate diameter of our Galaxy, the Milky Way? • 50 × 106 km • 50 astronomical units • 50 light-years • 50 kiloparsecs • 10 million light-years Q1.8
What is the approximate diameter of our Galaxy, the Milky Way? • 50 × 106 km • 50 astronomical units • 50 light-years • 50 kiloparsecs • 10 million light-years Q1.8
Key Ideas • Astronomy, Science, and the Nature of the Universe: The universe is comprehensible. The scientific method is a procedure for formulating hypotheses about the universe. These are tested by observation or experimentation in order to build consistent models or theories that accurately describe phenomena in nature. • Observations of the heavens have helped scientists discover some of the fundamental laws of physics. The laws of physics are in turn used by astronomers to interpret their observations. • The Solar System: Exploration of the planets provides information about the origin and evolution of the solar system, as well as about the history and resources of Earth. • Stars and Nebulae: Studying the stars and nebulae helps us learn about the origin and history of the Sun and the solar system.
Key Ideas • Galaxies: Observations of galaxies tell us about the origin and history of the universe. • Angular Measure: Astronomers use angles to denote the positions and sizes of objects in the sky. The size of an angle is measured in degrees, arcminutes, and arcseconds. • Powers-of-Ten Notation is a convenient shorthand system for writing numbers. It allows very large and very small numbers to be expressed in a compact form. • Units of Distance: Astronomers use a variety of distance units. These include the astronomical unit (the average distance from Earth to the Sun), the light-year (the distance that light travels in one year), and the parsec.