Outer planets concepts: Outer planets The outer planets are those planets in the Solar System beyond the asteroid belt, and hence refers to the gas giants and ice giants, which are in order of their distance from the Sun: The outer planets all have ring systems, although all but Saturn's are faint when viewed from Earth. Another aspect common to the gas giants is their many natural satellites (moons), two of which are larger than the planet Mercury (Jupiter's Ganymede and Saturn's Titan). That pair and Io, Callisto, Europa, and Triton, are larger than Pluto and Eris. This region of space is
Moons of Uranus less than half that of Triton (the seventh-largest moon in the Solar System) alone. The largest of the satellites, Titania, has a radius of 788.9 km, or less than half that of the Moon, but slightly more than that of Rhea, the second-largest moon of Saturn, making Titania the eighth-largest moon in the Solar System. Uranus is about 10,000 times more massive than its moons. As of 2016, Uranus is known to have 13 inner moons. Their orbits lie inside that of Miranda. All inner moons are intimately connected to the rings of Uranus, which probably resulted from the fragmentation