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Jupiter: Physical Structure
Facts in Brief
| Mean Temperature | -108oC (165 K) |
| Diameter | 142,800 km |
| Mass | 1.8986 x 1027 kg |
| Density | 1,326 kg/m3 |
| Surface Gravity | 23.12 m/s2 |
| Surface Pressure | Much Greater than 100 Bars |
| Dipole Magnetic Field Strength | 4.28 Guass-Rj3 |
Jupiter’s interior composition differs greatly from the terrestrial planets encountered within the asteroid belt. It has less density, relatively speaking, and higher pressure. This pressure keeps the simple molecules of hydrogen and helium, which account for more than 99% of Jupiter, in a liquid state. Starting at the very center, the core of Jupiter is a rocky kernel 10 to 15 times the mass of the Earth. Surrounding it is the main bulk of the planet, an ocean of liquid metallic hydrogen. This rare state of hydrogen is only possible in pressure wells exceeding 4 million bars, hence (in our solar system) only in the interiors of Jupiter and Saturn. Enveloping this is the outermost layer of conventional molecular hydrogen and helium that gradually shifts from liquid to gas as it moves outward to the void. It was thought that these three layers were sharply defined by the phase-shift of hydrogen, but recent experiments have proved that only indistinct and nebulous boundaries exist.