Neptune

Neptune is the eighth and farthest major planet from the Sun. Its blue appearance and distant position make it one of the defining worlds of the outer Solar System.

Although Neptune marks the end of the major planets, the Solar System continues far beyond it through regions containing dwarf planets, smaller bodies, and deep-space spacecraft.

Neptune takes about 165 Earth years to complete one orbit around the Sun.

Its enormous orbital period provides one of the clearest demonstrations of how distance from the Sun changes the scale and timing of planetary motion.

Neptune's atmosphere contains hydrogen, helium, and methane and supports some of the fastest measured winds in the Solar System.

Its active weather demonstrates that worlds far from the Sun can still have powerful and dynamic atmospheric systems.

Voyager 2 flew past Neptune in 1989 after traveling through the outer Solar System.

Its encounter revealed details about Neptune, its rings, magnetic environment, and moons, including Triton.

A map that includes Mercury and Neptune makes the enormous range of planetary distances much easier to understand.

Neptune also creates a natural transition from major planets into dwarf planets, the Kuiper Belt, New Horizons, Voyager, and the future deep-space side of the TransitSatellite Library.

These linked mission pages explain how spacecraft have studied neptune: their objectives, paths, instruments, and results. Each page carries its own mission record rather than repeating the planet description.