Neptune is the eighth planet in this solar system. It's closest distance (Perihelion) to the "Sun" would be 2.75 billion miles. Neptune exhibits a mass 17 times larger than Planet Earth, and has a volume 57 times as large as our Planet.
Considering all that mass and volume, Neptune's gravitational pull is only 10% stronger than that of earth. Neptune was the last planet visited by Voyager II during it's twelve year journey from Earth. The average estimated diameter of Neptune is 30,533 miles. Neptune completes it's rotational day in approximately 16.1 hours. It takes this planet 164 years to complete a nearly circular orbit around the Sun.
Voyager II passed within 3000 miles of Neptune's north pole and found a magnetic field which was similar to that found on "Uranus". Neptune's atmosphere appears to be quite blue, with changing white clouds suspended above an apparent surface. T
The atmospheric composition of Neptune is estimated to be 80% hydrogen, 19% helium and 1.5% methane. In the noticeable cloud formations, were some apparent features reminiscent of the "Great Red Spot" found on "Jupiter", even to the counterclockwise rotation associated with a low pressure system in the southern hemisphere.
However in this case the atmospheric storm is known as the "Great Dark Spot".
Although lightning and auroras have been found on other giant planets, only the
aurora phenomenon has been seen on Neptune.
Neptune has eight satellites. Five of these will orbit Neptune in a half day or less. The Moons of Neptune are Triton, Nereid, Naiad, Thalassa, Despina, Galatea, Larissa and Proteus. Triton, the largest moon of Neptune is in a retrograde orbit suggesting that it was captured rather than being coeval with the Planet itself.
Triton is large enough to raise
tides and effect the weather on Neptune. One day, perhaps a million years from
now, Triton will come close enough to Neptune
to be torn apart by the gravitational pull of the planet. Triton has a thin atmosphere of nitrogen and evidence of active geysers on it's surface, at minus
460 0 F Triton is one of the coldest places in our solar system observed by Voyager II. Voyager II confirmed the existence of three rings around Neptune
composed of very fine particles. Voyager II also confirmed that Neptune is giving off 2.7 times as much heat energy as it receives from the "Sun".
This is indicative that Neptune is producing heat from internal sources. For a closer look at "Scooter" Click Here >