1. NEW CHAPTER Our Solar System CHAPTER the BIG idea Planets and other objects form a system around our Sun. Planets orbit the Sun at different distances. 3.1 The inner solar system has rocky planets. 3.2 The outer solar system has four giant planets. 3.3 3.4 CHAPTER OUTLINE Small objects are made of ice and rock.

2. VOCABULARY KEY CONCEPT CHAPTER HOME 3.1 SECTION OUTLINE SECTION OUTLINE astronomical unit (AU) Planets orbit the Sun at different distances. ellipse inner solar system Mercury, Venus, Earth, Mars, asteroids outer solar system Jupiter, Saturn, Uranus, Neptune, Pluto, comets The planets have different sizes and distances from the Sun.

3. VOCABULARY KEY CONCEPT CHAPTER HOME 3.1 SECTION OUTLINE SECTION OUTLINE astronomical unit (AU) Planets orbit the Sun at different distances. ellipse The planets have different sizes and distances from the Sun. The solar system formed from a disk of dust and gas. Massive objects became round.

4. VOCABULARY KEY CONCEPT CHAPTER HOME Earth’s average distance from the Sun, which is approximately 150 million kilometers (93 million mi). astronomical unit (AU) 3.1 KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY Planets orbit the Sun at different distances. astronomical unit (AU) ellipse

5. VOCABULARY KEY CONCEPT CHAPTER HOME An oval or flattened circle. ellipse 3.1 KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY Planets orbit the Sun at different distances. astronomical unit (AU) ellipse

6. VOCABULARY KEY CONCEPT CHAPTER HOME terrestrial planet The inner solar system has rocky planets. 3.2 SECTION OUTLINE SECTION OUTLINE The terrestrial planets are round and have layers. Atmospheres came from volcanoes and impacts. Four processes produce surface features. impact cratering tectonics weathering and erosion volcanism tectonics volcanism

7. VOCABULARY KEY CONCEPT CHAPTER HOME Earth or a planet similar to Earth that has a rocky surface. The four planets in the inner solar system, Mercury, Venus, Earth, and Mars, are terrestrial planets. terrestrial planet 3.2 KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY The inner solar system has rocky planets. terrestrial planet tectonics volcanism

8. VOCABULARY KEY CONCEPT CHAPTER HOME The processes in which the motion of hot material under a crust changes the crust of a space body. Earth has a specific type of tectonics called plate tectonics. tectonics 3.2 KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY The inner solar system has rocky planets. terrestrial planet tectonics volcanism

9. VOCABULARY KEY CONCEPT CHAPTER HOME The process of molten material moving from a space body’s hot interior onto its surface. volcanism 3.2 KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY The inner solar system has rocky planets. terrestrial planet tectonics volcanism

10. VOCABULARY KEY CONCEPT CHAPTER HOME 3.3 SECTION OUTLINE SECTION OUTLINE The outer solar system has four giant planets. ring gas giant The gas giants have very dense, deep atmospheres with layers of clouds. All four giant planets have ring systems. Close-up of Saturn’s rings

11. VOCABULARY KEY CONCEPT CHAPTER HOME A large planet that consists mostly of gases in a dense form. The four large planets in the outer solar system (Jupiter, Saturn, Uranus, and Neptune) are gas giants. gas giant 3.3 KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY The outer solar system has four giant planets. ring gas giant

12. VOCABULARY KEY CONCEPT CHAPTER HOME In astronomy, a wide, flat zone of small particles that orbit around a planet’s equator. ring 3.3 KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY The outer solar system has four giant planets. ring gas giant

13. VOCABULARY KEY CONCEPT CHAPTER HOME 3.4 SECTION OUTLINE SECTION OUTLINE Small objects are made of ice and rock. comet asteroid meteor The asteroid Eros Objects in the inner solar system are rocky. Pluto and most other objects in the outer solar system are made of ice and rock. Rocky asteroids and icy comets orbit the Sun and produce tiny fragments that may become meteors. meteorite

14. VOCABULARY KEY CONCEPT CHAPTER HOME A small, solid, rocky body that orbits the Sun. Most asteroids orbit in a region between Mars and Jupiter called the asteroid belt. asteroid 3.4 KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY Small objects are made of ice and rock. comet asteroid meteor meteorite

15. VOCABULARY KEY CONCEPT CHAPTER HOME A body that produces a coma of gas and dust; a small, icy body that orbits the Sun. comet 3.4 Small objects are made of ice and rock. KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY comet asteroid meteor meteorite

16. VOCABULARY KEY CONCEPT CHAPTER HOME A brief streak of light produced by a small particle entering Earth’s atmosphere at a high speed. meteor 3.4 Small objects are made of ice and rock. KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY comet asteroid meteor meteorite

17. VOCABULARY KEY CONCEPT CHAPTER HOME A small object from outer space that passes through Earth’s atmosphere and reaches the surface. meteorite 3.4 Small objects are made of ice and rock. KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY comet asteroid meteor meteorite

18. VOCABULARY KEY CONCEPT CHAPTER HOME I. Planets orbit the Sun at different distances. A. Planets have different sizes and distances. 1. Distances 3.1 KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY B. The solar system formed from a swirling cloud of gas and dust. 2. Orbits Planets orbit the Sun at different distances. astronomical unit (AU) ellipse

19. VOCABULARY KEY CONCEPT CHAPTER HOME B. Craters cover the surface of Mercury. II. The inner solar system has rocky planets. A. The terrestrial planets have rocky crusts. 3.2 KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY 1. Processes and Surface Features 2. Atmospheres The inner solar system has rocky planets. C. Volcanoes shape the surface of Venus. D. Erosion changes the appearance of Mars. 1. Surface of Mars terrestrial planet tectonics volcanism 2. Gases and Water on Mars

20. VOCABULARY KEY CONCEPT CHAPTER HOME D. Uranus and Neptune are extremely cold. III. The outer solar system has four giant planets. A. The gas giants have very deep atmospheres. 1. Uranus 2. Neptune 3.3 KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY The outer solar system has four giant planets. B. Jupiter is a world of storms and clouds. C. Saturn has large rings. ring gas giant

21. VOCABULARY KEY CONCEPT CHAPTER HOME IV. Small objects are made of ice and rock. A. Pluto and most objects in the outer solar system are made of ice and rock. B. Asteroids and comets orbit the Sun. 1. Pluto and Charon 2. Moons of Gas Giants 3.4 Small objects are made of ice and rock. 1. Asteroids 2. Comets 3. Meteors and Meteorites KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY comet asteroid meteor meteorite