Related topics: planets · solar system · jupiter

Hubble watches how a giant planet grows

Ever made a complete mess in your kitchen while baking? At moments it may look like flour is floating in the air, but once you've added plenty of water and formed your dough, the bread becomes more like a ball. A similar ...

Hubble sees changing seasons on Saturn

NASA's Hubble Space Telescope is giving astronomers a view of changes in Saturn's vast and turbulent atmosphere as the planet's northern hemisphere summer transitions to fall as shown in this series of images taken in 2018, ...

A 'super-puff' planet like no other

The core mass of the giant exoplanet WASP-107b is much lower than what was thought necessary to build up the immense gas envelope surrounding giant planets like Jupiter and Saturn, astronomers at Université de Montréal ...

High pressure causes hydrogen variants to collapse

Hydrogen exists as a gaseous compound of two hydrogen atoms (H2). Under normal laboratory conditions, H2 occurs in the variants "ortho hydrogen" and "para hydrogen." Until now, it has been unclear how these variants behave ...

The cosmic commute towards star and planet formation

The molecular gas in galaxies is organized into a hierarchy of structures. The molecular material in giant molecular gas clouds travels along intricate networks of filamentary gas lanes towards the congested centers of gas ...

How NASA's Webb Telescope will continue Spitzer's legacy

As one window to the universe closes, another will open with an even better view. Some of the same planets, stars and galaxies we first saw through the first window will appear in even sharper detail in the one that will ...

Why some planets eat their own skies

For many years, for all we knew, our solar system was alone in the universe. Then better telescopes began to reveal a treasure trove of planets circling distant stars.

Gas giant composition not determined by host star

A surprising analysis of the composition of gas giant exoplanets and their host stars shows that there isn't a strong correlation between their compositions when it comes to elements heavier than hydrogen and helium, according ...

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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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