Jupiter I. Bulk properties: density = 1.31 gm/cm2; radius = 71,400 km; moment of inertia not measured but presumed consistent with planet of primarily solar abundances with density governed by compression and possibly some gravitative differentiation (heavier elements sinking to center, i.e., increased He content in center).

II. Rotation and figure: 9.8hours, with differential rotation observed between equatorial and polar regions; J2/q2 = 0.173 (difference from Maclaurin spheroid due to effects of compression of hydrogen).

III. Composition and interior structure: starting models assume condensation from solar abundances, giving a planet composed primarily of hydrogen and helium. There are notable departures from solar abundances of heavier elements, which may be due to accumulation of additional mass by impacts of smaller bodies after initial condensation. Important structural divisions are hydrogen, metallic hydrogen, and He enriched center.

IV. Thermal structure: intrinsic luminosity is 30 times that of Earth, implying a strong internal heat source. The only plausible source seems to be cooling from initial formation, which is used to infer a central temperature of 3000 deg K.
Atmosphere is vigorously convecting, evidenced from cyclonic storms and rapidly changing surface features.

V. Magnetic field: dipole strength observed at its surface is more than 20 times larger than Earth's dipole field observed at its surface; quadrapole and octopole components of the field are much stronger than Earth's, suggesting that its active convective dyanamo is relatively closer to its surface compared to the relative location of outer core convection in the earth and the earth's surface.

Click here to view images of Jupiter and results from the Galileo probe of Jupiter's atmosphere. Some surprises from the Galileo probe include observation of a "drier" atmosphere than that predicted from results of earlier missions that observed Jupiter's atmosphere externally.