A large planet composed primarily of hydrogen and helium with a relatively small rocky core, characterized by thick atmospheres and low overall density. Jupiter and Saturn are the gas giants in our solar system.
The term emerged in the mid-20th century as astronomers distinguished between rocky terrestrial planets and the large, low-density outer planets. 'Gas' refers to their dominant atmospheric composition, while 'giant' describes their enormous size compared to terrestrial planets.
Try Another Word