Planets {Neptune, planet} can be eighth nearest to Sun and fourth-largest planet [discovered 1846].
properties
Diameter is 45,000,000 meters, four times Earth diameter. Mass is 17 times Earth mass. Density is 2.3 g/cm^3, because it is 25% hydrogen. Gravity is 1.18 of Earth gravity.
properties: rotation
Neptune rotates every 16 to 18 hours on axis tilted 29 degrees to orbit.
properties: magnetism
Neptune has magnetic field.
properties: temperature
Surface temperature is 50 K to 55 K.
Like Jupiter and Saturn, Neptune has internal heat source. Neptune radiates more than twice as much energy as it receives from Sun.
orbit
Neptune is 30 times farther from Sun than Earth, 4,500,000,000,000 meters from Sun. Circular orbit of 165 years slightly inclines to ecliptic.
layers
Neptune has rocky core, 16,000,000-meter diameter. Around core is ice 8,000,000 meters thick. Around that layer is molecular hydrogen.
atmosphere
Atmosphere is mostly hydrogen and helium with some methane. Blue color results from red-light absorption by methane. Neptune has argon clouds. Neptune has rapid winds in horizontal bands and has large storms or vortices. Winds are fastest in solar system, reaching 2000 kilometers per hour. Large dark oval revolves around Neptune every 18 hours. Second dark spot revolves around Neptune every 16 hours.
moons
Neptune has many moons. Triton is main moon and is bigger than Moon. Gravitational effect of smaller moon defines rings. Adams Ring is 63,000 km from center of Neptune. Leverrier Ring is 53,000 km. Galle Ring is 42,000 km. All rings are closer to Neptune than Moon is to Earth.
Physical Sciences>Astronomy>Solar System>Planet>Planets
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Date Modified: 2022.0224