Related topics: planets · solar system · jupiter

Small stars may host bigger planets than previously thought

Stars with less than half the mass of our sun are able to host giant Jupiter-style planets, in conflict with the most widely accepted theory of how such planets form, according to a new study led by UCL (University College ...

NASA's Ingenuity helicopter sees a beautiful sunset on Mars

Sunsets provide some of the most beautiful natural imagery anywhere on Earth. People flock from all over to see sunsets at specific places at specific times, such as when they perfectly align down a street in Manhattan. But ...

Two new gas giant exoplanets discovered with TESS

Astronomers report the detection of two new gas giant exoplanets using NASA's Transiting Exoplanet Survey Satellite (TESS). The newfound alien worlds, designated TOI-3984A b and TOI-5293A b, have very short orbital periods. ...

Tumultuous migration on the edge of the hot Neptune desert

All kinds of exoplanets orbit very close to their star. Some look like the Earth, others like Jupiter. Very few, however, are similar to Neptune. Why this anomaly in the distribution of exoplanets? Researchers from the University ...

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Gas giant

A gas giant (sometimes also known as a Jovian planet after the planet Jupiter, or giant planet) is a large planet that is not primarily composed of rock or other solid matter. There are four gas giants in our Solar System: Jupiter, Saturn, Uranus, and Neptune. Many extrasolar gas giants have been identified orbiting other stars.

Gas giants can be subdivided into different types. The "traditional" gas giants, Jupiter and Saturn, are composed primarily of hydrogen and helium. Uranus and Neptune are sometimes considered a separate subclass called ice giants, as they are mostly composed of water, ammonia, and methane; the hydrogen and helium in Uranus and Neptune is mostly in the outermost region. Among extrasolar planets, Hot Jupiters are gas giants that orbit very close to their stars and thus have a very high surface temperature; perhaps due to the relative ease of detecting them, Hot Jupiters are currently the most common form of extrasolar planet known.

Gas giants are commonly described as lacking a solid surface, although a more accurate description is to say that they lack a clearly-defined surface. Although they have rocky or metallic cores - in fact, such a core is thought to be required for a gas giant to form - the majority of the mass of Jupiter and Saturn is hydrogen and helium. In the planet's upper layers, these elements are gaseous, as they are on Earth, but further down in the planet's interior, they become compressed into liquids or solids, which become denser toward the core. Similarly, although the majority of Uranus and Neptune is icy, the extreme heat and pressure of these planets' interiors put the ices into less familiar physical states. Therefore, one cannot "land on" gas giants in a traditional sense. Terms such as diameter, surface area, volume, surface temperature, and surface density may refer only to the outermost layer visible from space.

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