Whenever you think of “planets,” odds are a saturnian shape is the first that comes up. After all, what better way to signify some exotic alien world than distinguishing it with an intricate ring system? The sixth planet from the Sun, Saturn’s about 9.5 times as big across as Earth, spanning some 75,000 miles (121,000 kilometers); this means more than 700 Earths could fit inside. It’s so far from the Sun, about 891 million miles (1.43 billion kilometers), that the Sun appears only about 1 percent as bright as it does from Earth. And because Saturn’s density is only about 12.5 percent of Earth’s, which is less than water, the planet is buoyant! If you could find a body of water big enough, it’d float.Learn more about the king of the planets by registering with Astronomy.com and gaining access to the video, "Tour the solar system: Saturn."