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

In classic models, based on what astronomers know about Jupiter and Saturn, gas giants need to have a solid core at least ten times as massive as the Earth to gather enough gas before the disc disappears.

From Popular-Science

A conjunction is a good time to reflect on our cosmic heritage, and on the long shadows cast by the gas giants.

From Nautilus

Despite such concerns, commitments to cutting carbon emissions to net zero, largely by 2050, have in fact grown, from both countries and companies, including legacy oil and gas giants like BP and Shell.

From Fortune

WASP-189b is a hot Jupiter planet, a gas giant similar to our own Solar System’s Jupiter, but with more extreme temperatures.

From Popular-Science

Not every gas giant in the solar system is like this, but they all also come with various other problems that would make it difficult for humans to visit up close.

From MIT Technology Review

The red spot of Jupiter and the bands on that gas-giant world moved in orderly fashion about its circumference.

From Project Gutenberg

He thought of the great gas-giant world he'd seen out a port on the way here.

From Project Gutenberg

The electron telescope could detect its larger planets, especially a gas-giant fifth-orbit world of high albedo.

From Project Gutenberg

Outer, gas-giant planets floated even more deliberately in larger paths.

From Project Gutenberg

It made for a rendezvous over a pole of the gas-giant planet which was the fourth planet from Kandar's sun.

From Project Gutenberg