Learning Objectives

Each statement represents the primary learning objective for the corresponding major heading within the chapter. After you complete the chapter, you should be able to:

15.1 Explain the geocentric view of the solar system and describe how it differs from the heliocentric view.

15.2 List and describe the contributions to modern astronomy of Nicolaus Copernicus, Tycho Brahe, Johannes Kepler, Galileo Galilei, and Isaac Newton.

15.3 Describe the formation of the solar system according to the nebular theory. Compare and contrast the terrestrial and Jovian planets.

15.4 List and describe the major features of Earth’s Moon and explain how maria basins were formed.

15.5 Outline the principal characteristics of Mercury, Venus, and Mars. Describe their similarities to and differences from Earth.

15.6 Summarize and compare the features of Jupiter, Saturn, Uranus, and Neptune, including their ring systems.

15.7 List and describe the principal characteristics of the solar system’s small bodies.

Concept Checks

 15.1 Why did the ancients believe that celestial objects had some influence over their lives? What is the modern explanation of the “guest stars” that suddenly appear in the night sky? Explain the geocentric view of the universe.

15.2 What major change did Copernicus make to the Ptolemaic system? Why was this change philosophically different? What data did Tycho Brahe collect that was useful to Johannes Kepler in his quest to describe planetary motion? Who discovered that planetary orbits are ellipses rather than circles? Explain how Galileo’s discovery of the phases of Venus supported the Copernican view of a Sun-centered universe. In your own words, describe the law of universal gravitation.

15.3 Briefly outline the steps in the formation of our solar system, according to the nebular theory. By what criteria are planets considered either terrestrial or Jovian? What accounts for the large density differences between the terrestrial and Jovian planets?

15.4 Briefly describe the origin of the Moon. Compare and contrast the Moon’s maria and highlands. How is crater density used in the relative dating of the Moon’s surface features?

15.5 What body in our solar system is most like Mercury? Venus was once referred to as “Earth’s twin.” How are these two planets similar? How do they differ from one another? What surface features do Mars and Earth have in common?

15.6 What is the nature of Jupiter’s Great Red Spot? What is distinctive about Jupiter’s satellite Io? What two roles do ring moons play in the nature of planetary ring systems?

15.7 Compare and contrast asteroids and comets. Where are most asteroids found? Where are most comets thought to reside? What eventually becomes of comets that orbit close to the Sun? What characteristic does a celestial body possess to be classified as a dwarf planet?

Exploring Our Solar System

The links below are to satellites and ROVs used to explore our solar system. Each have photos and videos that you may find interesting.

The Mars Phoenix Lander

Kepler Satellite

Cassini Mission (Saturn)

Voyager 1 and 2