The four terrestrial planets are known as Mercury, Venus, Earth and Mars, they are all rocky planets composed primarily of silicate rocks and/or metals. They are all the planets closest to the sun in our Solar System. The Gas Giant's or Jovian Planets and <span>are composed mainly of a combination of gases/elements: </span>hydrogen<span>, </span>helium<span>, and </span>water<span> that exist in various </span><span>physical states. These are Jupiter, Saturn, Uranus and Neptune. Behind them is the dwarf planet Pluto (which has recently been re-instated officially as a planet), this is located in the Kuiper Belt.</span>
