Gas giants are large planets that primarily consist of hydrogen and helium. They have thick atmospheres and lack a solid surface, making them different from terrestrial planets like Earth. The four main gas giants in our solar system are Jupiter, Saturn, Uranus, and Neptune. These planets are known for their massive sizes and strong gravitational fields. They often have complex weather systems, including storms and high-speed winds. Some gas giants also have rings and numerous moons, with Jupiter and Saturn being particularly famous for their extensive moon systems.