As the 8th planet in the solar system, Neptune is also the smallest and the coldest of the four giant outer planets, and as well the most far away from the Sun. Just one spacecraft, Voyager 2, has been to investigate this world.
When the probe flew by in 1989, it provided the first close-up view of Neptune, revealing it to be a blue globe with frozen methane clouds in the atmosphere and a ring system. The planet has only 13 moons,compared to Jupiter, named after minor water deities of the Greek mythology. Neptune is also named after the roman god of water.
Neptune takes 169.37 Earth years to orbit the Sun, so it has completed only one circuit since its discovery in 1846. Structurally, Neptune is similar to Uranus, with a core of rock and metal surrounded by a liquid layer of water, ammonia, and methane. Above this is Hydrogen-dominated atmosphere affected by wind with speeds up to 2 000 km/h (1 240 miles/h) — the strongest winds in the solar system!0
The atmosphere temperatures can reach -210 C (-353 F).
Neptune’s ring system expands up to 41 000 to 64 000 km (25 500 to 40 000 miles) from the planet.
Neptune cannot be observed with the naked eye, but with a pair of binoculars or telescope you can observe the planet 4 350 000 000 km away from our home as a tiny blue disk…
Source: Smithsonian nature guide STARS AND PLANETS