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Saturn: Interior and Physical Structure
Quick Facts
| Mean Temperature | - 176oC |
| Diameter | 120,000 km |
| Mass | 5.68 x 1026 kg |
| Density | 687 kg/m3 |
| Surface Gravity | 8.96 m/s2 |
| Surface Pressure | >100 Bars |
| Dipole Magnetic Field Strength | 0.210 Guass-Rs3 |
Though Saturn is only second to Jupiter in size, it is the least dense of the planets, with a comparative density of 0.7 (compared to 1.0 for water). Constituted similarly to Jupiter, 75% of Saturn is composed of hydrogen and 25% of helium. It still retains trace amounts of the water, methane, ammonia, and rock from its birth in the pre-solar system nebula.
The center of Saturn is a rocky core. Surrounding it is a liquid metallic hydrogen layer, surrounded in turn by a molecular hydrogen layer. The core is a sizzling 1.20 x 105 degrees Celsius: Saturn radiates more energy than it receives from the Sun. Like Jupiter, much of this heat is due to the Kelvin-Helmholtz mechanism: the slow, self-regulated coupling of cooling and gaseous contracting, where the gasses of a solar body becomes more “condensed” as they bleed heat into the atmosphere. Saturn still radiates more heat than the Kelvin-Helmholtz principle can explain. Consequently, atronomers believe that there is another mechanism at work leaking the ancient heat of Saturn’s core out into space.