The Outer Planets

Jupiter

Although it takes 12 years to revolve around the Sun, Jupiter rotates faster than any other planet. Jupiter and all the other planets have a ring system.

Uranus

Beneath Uranus's atmosphere is a slushy layer of water, ammonia, and other materials. Uranus might have a rocky core.

Jupiter

Jupiter is the largest planet in the solar system. Jupiter's atmosphere contains helium but is mostly made up of hydrogen. Jupiter's entire structure is made up of about 80 percent hydrogen, about 20 percent helium, and small amounts of other materials. Jupiter has a solid core that is surrounded by liquid hydrogen. The four largest moons of Jupiter are called Galilean moons. These are Io, Europa, Ganymede, and Callisto.

Jupiter

Jupiter's rotation stretches its clouds into colorful bands. The Great Red Spot on Jupiter is a storm that has lasted more than 300 years.

Saturn

Like Jupiter, Saturn rotates rapidly and has clouds in bands. Saturn is mostly made of hydrogen and helium. Saturn has the largest ring system in the solar system. Most of Saturn's moons are small, but one of them, Titan, is larger than the planet Mercury.

Saturn

Saturn has seven bands of rings, each of which contains thousands of narrower ringlets. The rings are made mainly of ice particles.

Neptune

The atmosphere and interior of Neptune are similar to Uranus. Neptune has at least 13 moons and a faint ring system.

The Outer Planets

The outer planets are made of elements that are usually gases on Earth. Gravitational forces produced by the large sizes of these planets change gases into liquids.

Uranus

Uranus's atmosphere contains mostly hydrogen and helium, with small amounts of methane. The rotational axis of Uranus is tilted more than that of other planets. Uranus has at least 27 moons and a small ring system.