Neptune

IntroductionThe Latest: NASA's Hubble Space Telescope confirmed the presence of a dark vortex in the atmosphere of Neptune. Though similar features were seen during the Voyager 2 flyby of Neptune in 1989 and by the Hubble Space Telescope in 1994, this vortex is the first one observed on Neptune in the 21st century.

Neptune's dark vortices are high-pressure systems and are usually accompanied by bright "companion clouds," which are also now visible on the distant planet. The bright clouds form when the flow of ambient air is perturbed and diverted upward over the dark vortex, causing gases to likely freeze into methane ice crystals.

Dark, cold and whipped by supersonic winds, ice giant Neptune is the eighth and most distant planet in our solar system. More than 30 times as far from the Sun as Earth, Neptune is the only planet in our solar system not visible to the naked eye. In 2011 Neptune completed its first 165-year orbit since its discovery in 1846. Explore Neptune ›

Ten Things to Know About Neptune

Giant

Neptune is about four times wider than Earth. If Earth were a large apple, Neptune would be the size of a basketball.

Eighth Wanderer

Neptune orbits our Sun, a star, and is the eighth planet from the Sun at a distance of about 2.8 billion miles (4.5 billion kilometers).

Short Day, Long Year

Neptune takes about 16 hours to rotate once (a Neptunian day), and about 165 Earth years to orbit the sun (a Neptunian year).

Global Color Mosaic of Triton

Ice Giant

Neptune is an ice giant. Most of its mass is a hot, dense fluid of "icy" materials – water, methane and ammonia – above a small rocky core.

Gassy

Neptune's atmosphere is made up mostly of molecular hydrogen, atomic helium and methane.

Many Moons

Neptune has 13 moons (and one more awaiting confirmation of discovery), which are named after sea gods and nymphs in Greek mythology.

Faint Rings

Neptune has six known rings.

One Voyage There

Voyager 2 is the only spacecraft to have visited Neptune. No spacecraft has orbited this distant planet to study it at length and up close.

Lifeless

Neptune cannot support life as we know it.

One Cool Fact

Because of dwarf planet Pluto’s elliptical orbit, Pluto is sometimes closer to the Sun (and us) than Neptune is.

Triton South Polar Terrain

Did You Know?

Neptune is our solar system's windiest world. Winds whip clouds of frozen methane across the planet at speeds of more than 2,000 km/h (1,200 mph)—close to the top speed of a U.S. Navy F/A-18 Hornet fighter jet. Earth's most powerful winds hit only about 400 km/h (250 mph).

F/A-18 Chase Aircraft — NASA Dryden F/A-18 #852 mission support aircraft in flight. Image Credit: NASA Photo / Lori Losey

Pop Culture

Even though Neptune is the farthest planet from our Sun, it's a frequent stop in pop culture and fiction. The planet served as the backdrop for the 1997 science fiction horror film Event Horizon, while in the cartoon series Futurama, the character Robot Santa Claus has his home base on Neptune's north pole. Dr. Who fans will remember that an episode entitled "Sleep No More" is set on a space station orbiting Neptune. And in the Star Trek: Enterprise pilot episode, "Broken Bow," viewers learn that at warp 4.5 speed, it is possible to fly to Neptune and back to Earth in six minutes

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