Outer planets 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 also
Geologic time scale A key aspect of the work of the International Commission on Stratigraphy is to reconcile this conflicting terminology and define universal horizons that can be used around the world. Some other planets and moons in the Solar System have sufficiently rigid structures to have preserved records of their own histories, for example, Venus, Mars and the Earth's Moon. Dominantly fluid planets, such as the gas giants, do not preserve their history in a comparable manner. Apart from the Late Heavy Bombardment, events on other planets probably had little direct influence on the Earth, and events on Earth had correspondingly little