The distance from Jupiter to Saturn is about 65 meters in our model, or nearly three-fourths the length of a football field; notice how much longer this walk takes than the few steps between the planets of the inner solar system. Saturn is only slightly smaller than Jupiter in size but is considerably less massive (about one-third Jupiter’s mass) because it is less dense. Like Jupiter, Saturn is made mostly of hydrogen and helium and has no solid surface.

Saturn is famous for its spectacular rings. Although all four of the giant outer planets have rings, only Saturn’s can be seen easily through a small telescope on Earth. The rings may look solid from a distance, but this appearance is deceiving. If you could wander into the rings, you’d find yourself surrounded by countless individual particles of rock and ice, ranging in size from dust grains to city blocks. Each particle orbits Saturn like a tiny moon.

More than one hundred moons orbit Saturn. Most are far too small to be visible in our model solar system (though they are still considerably larger than the ring particles). But Saturn’s largest moon, Titan, is bigger than the planet Mercury and is blanketed by a thick atmosphere. On Titan’s surface, you’d find an atmospheric pressure slightly greater than that on Earth, and you would inhale air with roughly the same nitrogen content as air on Earth. However, you’d need to bring your own oxygen, and you’d certainly want a warm spacesuit to protect yourself against frigid outside temperatures. In 2005, NASA’s Cassin spacecraft released the European Space Agency’s Huygens probe, which successfully landed on Titan — making Titan by far the most distant world on which a human-built spacecraft has landed.