Definition

Noun: A gas giant is a very large planet that is composed primarily of hydrogen and helium, with no well-defined solid surface. These planets are characterized by their massive size, deep atmospheres, and often have systems of rings and many moons.

Examples

• Jupiter and Saturn are the two largest gas giants in our solar system.
• Astronomers have discovered many gas giants orbiting distant stars.
• Unlike rocky planets, a spacecraft cannot land on a gas giant.

Advanced Usage

• "Hot Jupiter": A class of exoplanets that are gas giants but orbit extremely close to their parent stars.
  • The first exoplanet discovered around a sun-like star was a hot Jupiter.
• "Ice Giant": Sometimes distinguished from gas giants, ice giants like Uranus and Neptune have a higher proportion of "ices" (water, ammonia, methane) in their composition alongside hydrogen and helium.
  • While often grouped with gas giants, Uranus and Neptune are more accurately classified as ice giants.

Variants and Related Words

• Jovian Planet (n): A synonym for gas giant, derived from Jupiter (Jove).
  • The four Jovian planets are Jupiter, Saturn, Uranus, and Neptune.
• Exoplanet (n): A planet that orbits a star outside our solar system. Many discovered exoplanets are gas giants.
  • The Kepler telescope was designed to search for exoplanets.

Synonyms

• Jovian planet
• Giant planet

Related Phrases

• Gas giant planet: A slightly more descriptive but redundant phrase.
  • The gas giant planet Saturn is famous for its spectacular ring system.

Noun

1. any of the four outermost planets in the solar system; much larger than Earth and gaseous in nature (like Jupiter)