Chapter Introduction

191

Saturn, Four of Its Moons, and Its Rings This Cassini image gives you a feel for how thin the rings of Saturn are.

The Outer Planets and Their Moons

WHAT DO YOU THINK?

  • Is Jupiter a “failed star”? Why or why not?

  • What is Jupiter’s Great Red Spot?

  • Does Jupiter have continents and oceans?

  • Is Saturn the only planet with rings?

  • Are the rings of Saturn solid ribbons?

Answers to these questions appear in the text beside the corresponding numbers in the margins and at the end of the chapter.

192

The four giant worlds lack solid surfaces and are so much larger, rotate so much faster, and have such different chemical compositions from our planet that upon seeing them one knows, to paraphrase Dorothy, “You’re not on Earth anymore.” There is nothing on Earth remotely similar to the swirling red and brown clouds of Jupiter, the ever-changing ring system of Saturn, or the blue-green clouds of Uranus and Neptune. The outer four worlds collectively have at least 170 moons, which have an amazing range of shapes, sizes, and surfaces. Some of these moons have water interiors; some have volcanoes; some have surface ice; one, Titan, has a thick atmosphere; and one, ice-covered Hyperion, is arguably the most bizarre-looking object in the solar system. We begin our exploration of the outer planets, and their moons and rings, with magnificent Jupiter.

In this chapter you will discover

193