New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Gas giant

A gas giant is a large planet that is not primarily composed of rock or other solid matter. Gas giants may have a rocky or metallic core—in fact, such a core is thought to be required for a gas giant to form—but the majority of its mass is in the form of the gases hydrogen and helium, with traces of water, methane, ammonia, and other hydrogen compounds. Unlike rocky planets, which have a clearly defined difference between atmosphere and surface, gas giants do not have a well-defined surface; their atmospheres simply become gradually denser toward the core, perhaps with liquid or liquid-like states in between. One cannot "land on" such planets in the traditional sense. There are four gas giants in our solar system: Jupiter, Saturn, Uranus, and Neptune.

Related Stories
 


Space & Time News

May 19, 2026

NASA’s Nancy Grace Roman Space Telescope is now aiming for an earlier launch in September 2026. Designed to explore dark matter, dark energy, and distant exoplanets, the telescope will capture massive, ultra-detailed surveys of the cosmos using ...
NASA is testing a next-generation space computer chip that could give spacecraft the ability to operate far more independently in deep space. The radiation-hardened processor is showing performance levels hundreds of times beyond current spaceflight ...
NASA’s Roman Space Telescope could expose a vast hidden population of neutron stars lurking unseen across the Milky Way. By detecting subtle shifts in starlight caused by gravity, the mission may ...
Astronomers using NASA’s James Webb Space Telescope have created the clearest map yet of the universe’s “cosmic web” — the enormous hidden structure that connects galaxies across space. By ...
NASA’s Psyche spacecraft is about to pull off a dramatic close flyby of Mars, skimming just 2,800 miles above the planet to get a powerful gravitational boost on its journey to the mysterious metal-rich asteroid Psyche. The maneuver will save ...
NASA’s Curiosity rover had an unexpectedly stubborn Mars souvenir after drilling into a rock nicknamed “Atacama” — the entire chunk ripped loose from the ground and stayed stuck to the rover’s drill. Engineers watched as Curiosity shook, ...
A bold step toward returning humans to the Moon is underway with Blue Origin’s uncrewed MK1 “Endurance” lander, designed to test the technologies that future astronauts will rely on. Built in ...
A powerful new electromagnetic thruster has taken a major step forward after a successful high-energy test at NASA’s Jet Propulsion Laboratory. Fueled by lithium vapor and driven by intense magnetic forces, the experimental engine reached ...
Artemis II proved NASA’s deep space systems are ready for the next leap. Orion survived its high-speed return with improved heat shield performance and pinpoint landing accuracy, while the SLS rocket nailed its trajectory. Even the launch pad ...
Voyager 1 just powered down a nearly 50-year-old instrument to stay alive in deep space. The spacecraft is running critically low on energy, forcing NASA to make careful sacrifices to keep its mission going. Despite the shutdown, it continues to ...
Astronomers have unleashed a powerful new AI tool called RAVEN to comb through data from NASA’s TESS mission—and it’s paying off in a big way. By analyzing millions of stars, the system has ...
A group of undergraduate students pulled off something remarkable: they built their own dark matter detector and used it to probe one of physics’ biggest mysteries. Working with limited resources but plenty of creativity, they designed a ...

Latest Headlines

updated 12:56 pm ET