Composition

    Uranus has a core made of rocks, metals, and ices.  The core is about 4,500 miles (7,200 km) in radius, or 28 percent of the planet's total radius.  The temperature at the core is 12,000¡F (6650¡C).

    Surrounding the core is a hot, slushy mantle.  The slush is made of water, liquid ammonia, and liquid methane.  This mantle is about 6,700 miles (10,800 km) deep, or 42 percent of the total radius.

    Above the mantle is a deep atmosphere.  The atmosphere is mostly hydrogen, helium, and methane.  Uranus's atmosphere rises about 4,800 miles (7,700 km) above the mantle.  The atmosphere is 30 percent of its total radius.