Gas Giant Interiors
1 2016-04-05T10:08:06+00:00 Brock Earth Sciences 443498efbb7251f48d0d638e5c57b8774f100004 14 1 *Jupiter* Jupiter's composition is mainly hydrogen and helium. In contrast to planetary bodies covered with a hard surface crust (the Earth, for example), the jovian surface is gaseous-liquid, rendering the boundary between the atmosphere and the planet itself almost indistinguishable. Below the roughly 1000-kilometer-thick atmosphere, a layer of liquid hydrogen extends to a depth of 20,000 kilometers. Even deeper, it is believed that there is a layer of liquid metallic hydrogen at a pressure of 3 million bars. The planet core is believed to comprise iron-nickel alloy, rock, etc., at a temperature estimated to exceed 20,000C. *Saturn* As with Jupiter, Saturn is mainly composed of hydrogen and helium and is observed to be of extremely low density. In fact, Saturn's mean density is only about two-thirds that of water. The Saturn atmosphere comprises, in descending order of altitude, a layer of ammonia, a layer of ammonium hydrogen sulfide, and a layer of ice. Below this, the saturnian surface is a stratum of liquid hydrogen (as in the case of Jupiter) underlain with a layer of liquid metallic hydrogen. It is believed that the liquid hydrogen layer of Saturn is thicker than that of Jupiter, while the liquid metallic hydrogen layer may be thinner. The planet's core is estimated to be composed of rock and ice. *Uranus* Uranus is gaseous in composition, mainly comprising hydrogen and helium as in the case of Jupiter and Saturn. The planet atmosphere is mostly hydrogen but also includes helium and methane. The planet core is estimated to be rock and ice encompassed by an outer layer of ice comprised of water, ammonium, and methane. *Neptune * The atmosphere of Neptune consists of mainly hydrogen, methane and helium, similar to Uranus. Below it is a liquid hydrogen layer including helium and methane. The lower layer is made up of the liquid hydrogen compounds oxygen and nitrogen. It is believed that the planet core comprises rock and ice. Neptune's average density, as well as the greatest proportion of core per planet size, is the greatest among all the gaseous planets. *Image Credit:* Lunar and Planetary Institute plain 2016-04-05T10:08:06+00:00 Internet Archive SPD-SLRSY-166 image What -- Neptune What -- Uranus What -- Saturn What -- Jupiter What -- Earth Planets Jet Propulsion Laboratory Solar System Exploration Brock Earth Sciences 443498efbb7251f48d0d638e5c57b8774f100004This page is referenced by:
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The Outer Planets
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The outer, Jovian (named after Jupiter) planets consist of Jupiter, Saturn, Uranus, Neptune.
While these planets are large in diameter, their densities are relatively low, ranging from 687 to 1638 kg/m3 or 0.687 to 1.638 g/cm3. With a density of less than 1 g/cm3, Saturn would theoretically float on water. These planets cannot be rocky bodies and they are indeed primarily composed of gases and liquids. Their surface pressures are unknown because their surfaces are deep in their atmosphere and the locations and pressures are not known.
These planets have also managed to acquire a large number of moons, but we will see later that the really interesting moons are the inner, larger ones. This image shows the major moons of the outer planets, in relation to our moon. Also added into this size comparison are Mars' moons and Pluto's moon Charon, and of course the Earth itself.
To see how these larger moons compare to all the moons within the solar system see this image. We should point out that this image is at least 7 years old and we keep discovering more moons in the outer regions of the solar system. At present, Jupiter has at least 67 moons alone.
And even though it is no longer a planet, we'll stop at Pluto next.