gas giant

[ gas jahy-uhnt ]

noun

, Astronomy.

1. a giant planet composed mostly of hydrogen and helium: the two gas giants in our solar system, Jupiter and Saturn, are sometimes called failed stars because their composition is similar to that of stars, but this is largely considered misleading, as gas giants, unlike brown dwarfs, do not form as stars do. Compare ice giant ( def ).

gas giant

noun

1. one of the four planets in our solar system that are composed chiefly of hydrogen and helium, namely Jupiter, Saturn, Uranus, and Neptune

gas giant

1. A large, massive, low-density planet composed primarily of hydrogen, helium, methane, and ammonia in either gaseous or liquid state. Gas giants have swirling atmospheres primarily of hydrogen and helium, with no well-defined planetary surface; they are assumed to have rocky cores. They are also characterized by ring systems, although only Saturn's is readily visible from Earth. Our solar system contains four gas giants: Jupiter, Saturn, Uranus, and Neptune. The majority of extrasolar planets discovered so far are the size of the solar system's gas giants, although they orbit their stars much more closely and may differ in composition from ours.
2. Also called Jovian planet
3. Compare terrestrial planet

Word History and Origins

Origin of gas giant¹

First recorded in 1950–55

Word History and Origins

Origin of gas giant¹

C20: coined by James Blish (1921–75), US science fiction writer

Example Sentences

It will get a gravity assist by sling-shotting around Mars early next year, then boomerang back around Earth in late 2026 before zooming toward the gas giant and its icy, dynamic moon.

From Los Angeles Times

Oil and gas giants BP and Equinor will be among the firms providing private sector funding for the projects, she said, adding that other countries "would love to get this sort of investment".

From BBC

Its red hue, which is due to atmospheric chemical reactions, stands in stark contrast with the gas giant's other pale clouds.

From Science Daily

Siegelman first made the connection between our planet and the gas giant in 2018 when she noticed a striking similarity between images of Jupiter's huge cyclones and the ocean turbulence she was studying.

From Science Daily

Consequently, observations indicate that rocky planets with sizes similar to Earth form more efficiently than Jupiter-like gas giants in the disks around very low-mass stars, the most common stars in the Universe.

From Science Daily