What defines a gas giant planet?

A gas giant planet is characterized by its large size and gaseous composition. These planets typically have a thick atmosphere made up largely of hydrogen and helium, which contributes to their substantial mass and size when compared to terrestrial planets, which are smaller and rocky.

Gas giants also lack a well-defined solid surface and can have complex weather systems, including storms and high-speed winds. Jupiter and Saturn are prime examples of gas giants, demonstrating features like ring systems and numerous moons. Understanding these characteristics helps distinguish gas giants from other types of planets, particularly terrestrial ones, which are smaller, denser, and primarily composed of rock and metal.