Take a closer look at the four gas giants. They're called gas giants because they're made of gas – and they're giant! Our universe - Space adventure - Gas giants Learning Points Four of the planets in our solar system are known as the gas giants. These are Jupiter, Saturn, Uranus and Neptune. They are known as the gas giants because they are mostly made of gas. A Twig Junior Film - Core science concepts explained in an easy way for the youngest students.