Planet Neptune: Facts and Features

• Neptune is a dark, cold, and very windy planet, and it's the last one in our solar system.
• It is more than 30 times as far from the sun as Earth.
• It is similar to Uranus
• Neptune is composed of a thick fog of water, ammonia, and methane over an Earth-sized solid center.
• It was named after the Roman god of the sea.
• Sunlight takes 4 hours to travel from the Sun to Neptune.
• The atmosphere is made up of hydrogen, helium, and methane.
• Methane is what gives Neptune the same blue color as Uranus.
• Neptune has a thick atmosphere, making it the windiest world in our solar system.
• Winds can be three times stronger than Jupiter's and nine times stronger than Earth's, despite the planet's distance and low energy input from the Sun.
• In 1989, the "Great Dark Spot," a large, oval-shaped storm in Neptune's southern hemisphere, was large enough to contain the entire Earth, but it has since disappeared.
• At least six rings and four more ring arcs exist around Neptune, but they are hard to see.
• A day on Neptune is 16 hours long, while it takes 165 Earth years for it to orbit the sun once.
• Neptune was discovered in 1846, and in 2011, it completed its first 165-year orbit since its discovery.
• Neptune has 14 moons including Triton, its largest, discovered in 1846, 17 days after Neptune.
• Triton is the only large moon in the solar system to orbit backward, suggesting it may have been captured.
• Triton has surface temperatures around minus 235 degrees Celsius making it extremely cold.
• Voyager 2 discovered geysers on Triton spewing icy material upward more than 8 kilometers.
• Triton's thin atmosphere, discovered by Voyager, has been detected from Earth several times and is growing warmer.

Neptune's Exploration

• Voyager 2 is the only spacecraft to have visited Neptune
• After traveling for nine years and 3 billion kilometers, Voyager 2 gathered information about Uranus, including its rings and moons, in only six hours.
• Observations from the Hubble Space Telescope and powerful ground-based telescopes contribute to knowledge of Uranus.
• Voyager 2 discovered 10 new moons, two new rings, and a stronger magnetic field than Saturn.
• On March 18, 2011, New Horizons passed the orbit of Uranus on its way to Pluto.
• This made it the first spacecraft to travel beyond Uranus' orbit since Voyager 2.
• Uranus was not near the crossing point.
• The spacecraft is dormant during the majority of its eight-year interplanetary journey from Jupiter to Pluto.
• To perform necessary checkups, mission controllers wake up New Horizons for 50 days each year.