A gas giant is a large planet that primarily consists of hydrogen and helium, with a thick atmosphere and no solid surface. These planets are known for their massive sizes and strong gravitational fields. The four main gas giants in our solar system are Jupiter, Saturn, Uranus, and Neptune. Gas giants often have complex weather systems, including powerful storms and high-speed winds. They can also have numerous moons and ring systems. Unlike terrestrial planets, gas giants are not made up of rock and metal, making them unique in their composition and structure.