Gas giant
hideA 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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News tagged with giant planets
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Sep 18, 2009 |
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(PhysOrg.com) -- Studies of features in Jupiter’s spectacular and rapidly changing aurorae have given new insights into the complex electromagnetic interactions between the giant planet and two of its innermost ...
Saturn to Pull Celestial Houdini on August 11
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Aug 10, 2009 |
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(PhysOrg.com) -- In 1918, magician extraordinaire Harry Houdini created a sensation when he made a 10,000 pound elephant disappear before a mystified audience of over 5,200 at New York's famed Hippodrome theatre. ...
What Hit Jupiter?
Space & Earth / Space Exploration
Aug 03, 2009 |
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(PhysOrg.com) -- It began with a furrowed brow, a moment of puzzlement, quickly dismissed.
Wind estimate 'shortens Saturn's day by five minutes'
Jul 29, 2009 |
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(PhysOrg.com) -- A new way of detecting how fast large gaseous planets are rotating suggests Saturn’s day lasts 10 hours, 34 minutes and 13 seconds - over five minutes shorter than previous estimates that ...
World's largest laser opens (w/Video)
May 29, 2009 |
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Scientists for decades have been hunting for ways to harness the enormous force of the sun and stars to supply energy here on Earth. The National Ignition Facility at the Lawrence Livermore Laboratory may spark the light ...
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Mar 12, 2009 |
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An international team of scientists have discovered a transparent form of the element sodium (Na). The team, led by Artem Oganov, Professor of Theoretical Crystallography at Stony Brook University, and Yanming ...
Scientists Find Asteroids Are Missing, and Possibly Why
Space & Earth / Space Exploration
Feb 25, 2009 |
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(PhysOrg.com) -- The patterns of missing asteroids are like the footprints of wandering giant planets preserved in the asteroid belt.
Team finds smallest transiting extrasolar planet ever
Feb 03, 2009 |
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The CoRoT satellite has discovered a planet only twice as large as the Earth orbiting a star slightly smaller than the Sun. It is the smallest extrasolar planet (planet outside our solar system) whose radius ...
Helium rains inside Jovian planets
Jan 26, 2009 |
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(PhysOrg.com) -- Models of how Saturn and Jupiter formed may soon take on a different look.
Moist Convection Can Drive Jet Streams on All Four Giant Planets
Space & Earth / Space Exploration
Oct 13, 2008 |
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(PhysOrg.com) -- Turbulence generated by thunderstorms can drive the multiple east-west jet streams on the giant planets – Jupiter, Saturn, Uranus, and Neptune – and explain a long-standing conundrum concerning ...
