Orbit and rotation

Neptune's atmosphere is made up mostly of hydrogen and helium with just a little bit of methane. Neptune's neighbor Uranus is a blue-green color due to such atmospheric methane, but Neptune is a more vivid, brighter blue, so there must be an unknown component that causes the more intense color.

The main axix of Neptune's magnetic field is tipped over by about 47 degrees compared with the planet's rotation axis.

Like Uranus, whose magnetic axis is tilted about 60 degrees from the axis of rotation, Neptune's magnetosphere undergoes wild variations during each rotation because of thi...

Neptune has at least five main rings and four prominent ring arcs that we know of so far. 

Starting near the planet and moving outward, the main rings are named Galle, Leverrier, Lassell, Arago and Adams. The rings are thought to be relatively young and short-lived.

Neptune's ring sys...

Day: 16 hours

Year: 165 Earth years

Radius: 15,299.4 miles | 24,622 kilometers

Planet type: Ice giant

Temperature: -392 degrees Fahrenheit / -200 degrees Celsius 

Moons:

Neptune does not have a solid surface. Its atmosphere (made up mostly of hydrogen, helium and methane) extends to great depths, gradually merging into water and other melted ices over a heavier, solid core with about the same mass as Earth.

Neptune is one of the two ice giants in the outer solar system (the other is Uranus). Most (80 percent or more) of the planet's mass is made up of a hot dense fluid of "icy" materials—water, methane and ammonia—above a small, rocky core. Of the giant planets, Neptune is the densest.

Scienti...

Neptune's environment is not conducive to life as we know it. The temperatures, pressures and materials that characterize this planet are most likely too extreme and volatile for organisms to adapt to.

With a radius of 5,299.4 miles (24,622 kilometers), Neptune is about four times wider than Earth. If Earth were the size of a nickel, Neptune would be about as big as a baseball.

From an average distance of 2.8 billion miles (4.5 billion kilometers), Neptune is 30 astronomical units away fr...

Neptune took shape when the rest of the solar system formed about 4.5 billion years ago, when gravity pulled swirling gas and dust in to become this ice giant. Like its neighbor Uranus, Neptune likely formed closer to the Sun and moved to the outer solar system about 4 billion years ago.

Neptune has 14 known moons, neptune's largest moon Triton was discovered on October 10, 1846, by William Lassell, just 17 days after Johann Gottfried Galle discovered the planet.

Since Neptune was named for the Roman god of the sea, its moons are named for various lesser sea gods and nymphs...