Home
Neptune Main
Location and Orbit
The Atmosphere and
Magnetosphere
The Surface
Interior and Physical Structure
Moons and Rings
Missions to Neptune
History and Timeline
References & Links
Quiz
Neptune: Interior and Physical Structure
Facts in Brief
| Mean Temperature | - 215oC (58 K) |
| Diameter | 49,523 km |
| Mass | 1.0247 x 1026 kg |
| Density | 1,638 kg/m3 |
| Surface Gravity | 11 m/s2 |
| Surface Pressure | >100 Bars |
| Dipole Magnetic Field Strength | 0.142 Guass-Rh3 |
At its very center, Neptune has an Earth-sized core of rock accumulated from the planet’s formulation. Unlike Jupiter or Saturn, Neptune does not have any internal layering, but seems to have a uniform composition. In a planet so far away from the sun, it should come as no surprise that most of a planet’s energy comes from other sources. In fact, Neptune radiates twice as much heat as it absorbs from the Sun. Yet it seems at first that a liquid, frozen planet would be incapable of a “core,” as found in the terrestrial planets of Earth and Venus. The answer is hypothetical and technical. In its simplest form, it suggests that the primordial heat, created by the nebula, gradually escapes through the hot, liquid hydrogen that surrounds the planet’s “core," causing it to convect a few centimeters per second.