Neptune's atmosphere is mostly hydrogen and helium. Methane gas in the upper part of the planet's atmosphere gives Neptune a beautiful blue color. High-altitude streaks of bright white clouds cross the blue atmosphere.

Several large storm systems have been spotted on Neptune. One notable storm, called the Great Dark Spot, vanished from the southern hemisphere at about the same time that a similar storm appeared in the north.

Neptune's thick atmosphere may conceal a rocky core far below the visible clouds.

Voyager 2, an American space probe, confirmed the presence of several thin rings around Neptune when it flew past the planet in 1989.

There is little or no breathable oxygen in Neptune's atmosphere, but there is a great deal of methane, which is poisonous to humans. Winds rip through the atmosphere at hundreds of miles per hour.

You could not see the Sun, stars, or any of Neptune's moons through the thick cloud cover.

Since they have no internal heat source to warm them, Neptune's moons are even colder than the planet itself. Triton's surface is colder than any other planet or moon in the solar system. Through Triton's thin atmosphere, the Sun would look more like a bright star than the disk we see from Earth.