Rocky Planets

The rocky planets are mostly made up of rock and metal. These planets are very heavy and move slowly. They also do not have rings and very few moons.

ROCKY PLANETS (Mercury - Venus - Earth - Mars )


http://planets.sciencedaily.com/d/c/Rocky

Gas Planets

Gas Planets

  

Gas planets are a category of planets without any solid metals or rock. Gas planets are also referred to as gas giants, giant planets, and Jovian planets. Since gas planets do not have a solid surface, you would not be able to walk on them. Gas planets are said to have a rocky center; however, that term is somewhat misleading. Scientists believe that due to the high temperatures and extreme pressures in the center of gas planets their rocky centers are actually liquid metal or rock. Thus, the density of the gas planets simply increases as you go deeper to the center.

There are four gas planets in our Solar System: Jupiter, Saturn, Uranus, and Neptune. The other four planets are known as terrestrial planets. The gas giants in our Solar System are also called the outer planets because they are the four planets in the Solar System furthest from the Sun

http://en.wikipedia.org/wiki/Gas_giant