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| Quick Facts
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Distance to Sun : 2.793 billion miles
Period of Revolution/Length of Year : 164.79 Earth years
Period of Rotation/Lenth of Day : 16.03 Earth hours
Orbit Eccentricity : 0.009
Orbit Inclination : 1.8 degrees
Mass : 1.024 x 10^26 kg
Mass : 17.204 Earths
Diameter 48,598.97 km (30,198 miles)
Gravity : 1.19 Earths
Density : 1.76
Tilt of Axis : 29.6 degrees
Rings of Neptune
1989N3R
Distance From center of Neptune : 41,900 km (26,035.45 miles)
Width : 15 km (9.32 miles)
Thickness : Unknown
Mass : Unknown
Albedo : low
1989N2R
Distance From center of Neptune : 53,200 km (33,056.94 miles)
Width : 15 km (9.32 miles)
Thickness : Unknown
Mass : Unknown
Albedo : low
1989N4R
Distance From center of Neptune : 53,200 km (33,056.94 miles)
Width : 5,800 km (3,603.95 miles)
Thickness : Unknown
Mass : Unknown
Albedo : low
1989N1R
Distance From center of Neptune : 62,930 km (39,102.889 miles)
Width : 50 km (31.06 miles)
Thickness : Unknown
Mass : Unknown
Albedo : low
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| About Uranus
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Neptune was discovered on September 23, 1846 by Johann Gottfried Galle, of the Berlin Observatory, and Louis d'Arrest, an astronomy student, through mathematical predictions made by
Urbain Jean Joseph Le Verrier. It is the outermost planet of the gas giants. If Neptune
were hollow, it would contain almost 60 Earths. It has eight moons, six of which were
found by the Voyager space probe.
The first two thirds of Neptune is composed of a mixture of molten rock, water, liquid ammonia and methane. The outer third is a mixture of heated gases comprised of hydrogen, helium, water and methane. Methane in the outer atmosphere gives Neptune its blue cloud color. Neptune has several large, dark spots like those of Jupiter's hurricane-like storms. The largest spot, known as the Great Dark Spot, is about the size of the earth.
Long bright clouds, similar to cirrus clouds on Earth, were seen high in Neptune's atmosphere. At low northern latitudes, Voyager captured images of cloud streaks casting their shadows on cloud decks below.
Neptune has the strongest winds of any place in the entire solar system. Most of the winds there blow westward, opposite to the rotation
of the planet. Near the Great Dark Spot, winds blow up to 2,000 kilometers (1,200 miles) an hour.
Neptune has a set of four rings which are narrow and very faint. The rings are made up of dust particles thought to have been made by tiny meteorites smashing into Neptune's moons. From ground based telescopes the rings appear to be arcs but from
Voyager 2 the arcs turned out to be bright spots or clumps in the ring system. The exact cause of the bright clumps is unknown.
The magnetic field of Neptune, like that of Uranus, is highly tilted at 47 degrees from the rotation axis and offset at least 0.55 radii (about 13,500 kilometers or 8,500 miles) from the planet center. Comparing the magnetic fields of the two planets, scientists think the extreme orientation may be characteristic of flows in the interior of the planet and not the result of that planet's sideways orientation or of any possible field reversals at either planet.
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